It is our privilege to present to you the first edition of the B-Word for this academic year. This winter we’ve had wonderfully varied articles covering topics from the neuroscience of death, to the vital roles played by predators, from domesticating horses to cardiovascular disease and much more! We would like to thank our writers for their hard work in taking the time to contribute these brilliant pieces - we know this has been a very busy term!
Enjoy reading and have a wonderful Christmas!
The B-Word Editorial Team
Avnika, Elizabeth and Lucia
The Triggers of Neurodegenerative Diseases
By Olivia Haselden
What Are Neurodegenerative Diseases?
The term “neurodegenerative disease” encompasses a variety of conditions that arise from damage or loss of neurones in the brain (especially the cortex) This can lead to negative e ects on motor and cognitive skills such as movement, memory and language, which can take away from a person’s independence
As the medical industry is advancing, the older population is beginning to increase, therefore the prevalence of these types of diseases is significantly growing which means the search for a cure is becoming more urgent. Finding a cure is immensely challenging for scientists due to the diverse pathology of the many conditions included in the umbrella term “neurodegenerative diseases” along with the general insu cient understanding of the brain. However, the only way to discover a cure for these devastating brain degenerative diseases is to completely and deeply understand how they come to be in the first place
As we have just established, there are many categories of neurodegenerative diseases, but in this explanation, we will focus in on three of the most common types of neurodegenerative disorders for each section: the causes of dementia- type diseases, the symptoms of Parkinson's-type diseases and the e ects motor neurone diseases
Investigating the pathophysiology of Alzheimer’s
Although the causes of most neurodegenerative diseases are unknown, there are a few theories on the medical cause of Alzheimer’s disease which is a dementia-type disease This may be since Alzheimer’s is the most common neurodegenerative disease, with “nearly 7 million Americans living with
Alzheimer's1 ” and “By 2050, this number is projected to rise to nearly 13 million2 . ” Also, according to the Alzheimer's association, “Alzheimer’s disease was the fifth-leading cause of death among people aged 65 and older in 20213 ” Alzheimer’s disease is a type of dementia and therefore is categorised as a neurodegenerative disease. Due to ongoing investigations on Alzheimer’s disease, two major brain changes that trigger Alzheimer’s have been discovered: plaques and tangles
Firstly, plaques are essentially clumps of molecules that can cause significant complications in the brain such as obstructing signals between neurones. However, there is much more fascinating detail to be shared about the formation and e ects of plaques
In cell membranes, there is a molecule called Amyloid precursor protein (APP) which is thought to aid in the repair and growth of damaged neurones.
Part of this molecule is found inside the cell and the remainder is found outside. Similar to other proteins, APP is used, broken down and then recycled.
In normal circumstances, alpha and gamma secretase are the only secretase enzymes that hydrolyse APP, which means the section outside of the cell is soluble However, in some cases, beta secretase becomes involved in the hydrolysis reaction which causes the section left outside the cell to be an insoluble monomer of amyloid beta4 .
4 The Science of Parkinson’s – Neurofibrillary tangles, [online], available: https://scienceofparkinsons.com/wp-content/uploads/2016/ 05/amyloid-plaque formation-big jpg
These monomers can clump together just outside of the neurone as they are chemically sticky which forms Amyloid Beta Plaques. These plaques disrupt neurone signals as they are found between neurones leading to impaired brain function5 .
The Amyloid Beta Plaques are also thought to trigger an immune response which causes damage to the brain due to the inflammation of surrounding neurones
An alternative idea is that amyloid plaque is deposited around blood vessels in the brain, which is called amyloid angiopathy. This increases the chances of haemorrhage due to the walls of the blood vessels becoming weak.
Another brain change in Alzheimer’s patients are tangles.
These occur inside the cell when the Amyloid beta plaque build-up forms pathways inside the cell. This activates the release of kinase which binds phosphate groups to the Tau protein (Tau protein is essentially the enzyme that maintains the cytoskeleton of neurones )
The binding of phosphate groups to the Tau proteins leads to a change in shape causing the protein to stop supporting the microtubules in the neuron’s cytoskeleton and instead clump with other Tau proteins.
‘Neurofibrillary Tangles’ is the name given to the clumps of Tau proteins. They lead to the dysfunction of neurones due to non-functioning microtubules as they cannot signal as well as neurones with normal functioning microtubules6 .
Sometimes neurofibrillary tangles can lead to apoptosis (programmed cell death). The brain
5 The Science of Parkinson’s – Neurofibrillary tangles, [online], available: https://scienceofparkinsons com/wp-content/uploads/2016/ 05/amyloid-plaque formation-big jpg
undergoes atrophy because of apoptosis meaning that it shrinks As a result, the gyri (characteristic folds of the brain) become narrower along with the sulci (grooves between the gyri) becoming wider as well as the ventricles (fluid-filled parts of the brain) becoming larger.
Triggers of brain changes
Now you are aware of the pathophysiology of Alzheimer’s disease, what are the causes of these changes in the brain?
The causes of Alzheimer’s disease can be categorised in two ways: sporadic and familial
Sporadic causes account for most Alzheimer’s cases and refer to the late onset of Alzheimer’s disease The exact cause may be unclear; however, it is most likely due to a combination of genetic and environmental factors.
For example, age is a major risk factor in the sporadic category with “1% of people aged 60-65 being a ected, but 50% of people aged 85 being a ected7 ”
An example of a genetic factor is when a person possesses the allele e4 Apolipoprotein This is because Apolipoprotein is responsible for the breakdown of beta amyloid, but the e4 variant causes this allele to be less e ective which leads to build up of amyloid beta and consequently an increased risk of amyloid beta plaques
Alternatively, familial factors are a less common cause of Alzheimer’s accounting for only around “5-10% of cases8 . ” These causes refer to the early onset of Alzheimer’s disease initiated by possessing a
dominant gene which speeds up the progression of Alzheimer’s
Symptoms of neurodegenerative diseases
Whilst the understanding of the sporadic and genetic causes of neurodegenerative diseases are important from a medical point of view, it is equally important to educate the public on the signs and symptoms that can indicate the beginning of these devastating diseases. Subsequent knowledge of symptoms may allow for the early diagnosis of such diseases This would be majorly beneficial for patients, along with their families, to come to terms, plan and prepare for the future of the patient
As mentioned earlier, there is a diverse variety in the pathology of neurodegenerative diseases which is due to three di erent reasons:
· Everybody’s brain is unique and individual
The symptoms depend on which part of the brain in a ected
Di erent causes lead to di erent symptoms
General symptoms of neurodegenerative disorders include confusion, memory loss, trouble thinking or concentrating as well as behavioural changes These are all commonly recognised to be obvious symptoms of many types of neurodegenerative diseases however people can easily become ignorant of these ‘red flag’ symptoms.
The above symptoms are quite stereotypical of neurodegenerative disorders and can also be presented due to other ordinary factors such as old age, but it is also essential to be aware of the less-known symptoms of these types of diseases
Whilst Parkinson’s disease is something that many people are aware of, it is not commonly associated by people with neurodegenerative diseases as the stereotypical symptoms are memory loss and confusion Parkinson’s on the other hand, a ects
coordination and muscle movement as opposed to cognitive skills which means that the symptoms are slightly di erent.
Initially, the person will experience mild tremors and di culty walking. At this stage the tremors typically only a ect one side of the body In phase two, the tremors worsen and begin to a ect both sides of the body. Next, the patient’s balance and coordination begin to deteriorate, and falls become a major concern. This leads to the final stage where tasks are incredibly challenging9
Some other symptoms include slow movements, shu ing steps and hunched posture which all contribute to the challenging nature of daily life.
Consequences of neurodegenerative diseases
All neurodegenerative diseases have life-changing, detrimental e ects on people’s ability to perform simple tasks that many of us take for granted. One type of neurodegenerative disease that can lead to major loss of independence is ALS which is the most common motor-neurone disease. The progression of this disease causes complete loss of muscle control which eventually leads to paralysis.
In the initial phases of the disease, people become clumsier and can have di culty with certain muscle movements for example chewing and swallowing This can cause concern to relatives and medical professionals who may encourage a carer to help the person with eating and other daily tasks to prevent injury to the person with ALS.
In the later stages of ALS, the loss of control over muscles may require assistive technology. For example, almost all patients with ALS will no longer be able to walk at some point in their journey with ALS When this happens, a power wheelchair can be used to help the person get around When the disease a ects the respiratory muscles causing breathing
9 Newsweek – Parkinson’s disease risk, [online], Available: Appendix Removal Linked to 20% Drop in Parkinson's Disease Risk - Newsweek
di culties, respiratory aids such as breathing pacemakers may also become necessary10
Despite the significant e ects of this disease patients still have the opportunity for a long-fulfilled life due to these types of technological aids. Take Steven Hawking for example, he received his ALS diagnosis at the age of 21 and was able to live up until the age of 76 and he was a famous leading physicist.
Getting Involved
To conclude, at this moment in time, all neurodegenerative diseases are incurable as their destruction of neurones is impossible to reverse. Nevertheless, scientists are beginning to develop many ways of treating the symptoms of these types of diseases with therapeutic and supportive options This can help to improve the lives of people living with neurodegenerative diseases.
Furthermore, intensive research continues to identify and develop new drug treatments. Progressing these promising preclinical results into successful interventions proves to be quite challenging in the complex field of neurodegenerative disease however, there are many ways in which you can get involved in the search for cures Fundraising and donating are great ways in which you can help charities such as Dementia UK, Alzheimer’s Society and Bart’s Charity, to name a few. All donations are utilised by researchers to continue their significant trials as well as patients being able to better manage their symptoms
10 Swiss Medica - The Stages of ALS: Understanding the Progression of the Disease, [online], Available: The Stages of ALS: Understanding the Progression of the Disease | Swiss Medica
The Neuroscience of Death
By Lydia Bews
When do we die?
Death is defined as irreversible cessation of circulatory and respiratory function11 , or no palpable pulse for greater than one minute12 . However, recent research has suggested that the termination of cardiac activity does not equate with the termination of brain activity. Upon this discovery, the question of what truly defines death begins to circulate.
Brain Activity After Death
Research on posthumous brain activity suggests that the human brain remains active from seconds to hours after the heart stops beating13 , which has been proven by gamma, delta, theta, alpha and beta oscillations remaining after death14 . These oscillations are commonly known as ‘brain waves’ and were originally thought to only be present in living brains. 15 However, when undergoing a brain
11(2017) National Library of Medicine, ‘Chapter 2-What and When is Death?’Remembering and Disremembering the Dead: Posthumous Punishment, Harm and Redemption over Time, available at: https://www ncbi nlm nih gov/books/NBK464649/#: :text = an%20individual%20who%20has%20sustained,brain%2 0stem%2C%20is%20dead %20 (Accessed 03/11/24)
12 (2017) How to Certify Death, Teach me Surgery, available at: https://teachmesurgery com/examinations/misc/confirma tion-of-death/ (Accessed 03/11/24)
13 Sara Reardon (2023), ‘Burst of brain activity during spying could explain life passing before our eyes,’ Science, available at:
15 First-ever recording of a dying human brain shows waves similar to memory flashbacks, The School of Medicine, available at: https://louisville edu/medicine/news/first-ever-recording -of-a-dying-human-brain-shows-waves-similar-to-me mory-flashbacks (Accessed 15/11/24)
scan after a fall, an 87-year-old male su ered a heart-attack resulting in sudden death. 16 Upon analysis of this post-humous activity, some broad conclusions regarding the final moments of one’s life can be made 17 As previously mentioned, brain waves can remain for up to thirty seconds after death18 , though arguably more interestingly is what these brain waves are associated with
A Replay of Life
Memory recall, dreaming and meditation can all linked to the brain activity that occurs immediately after death 19 Researchers invited a group of individuals who had undergone near death experiences and investigated the specific oscillations each had present during their experiences and interviewed them on their own cognitive and personal experience 20 From this, a general idea of what happens in the brain in the
16 Holly Honderich (2022) Life may actually flash before your eyes on death- new study, BBC News, Washington, available at: https://www.bbc.co.uk/news/world-us-canada-60495730# :~:text=A%20team%20of%20scientists%20set,recording%2 0of%20a%20dying%20brain (Accessed 15/11/23)
17 Shawn Radcli e (2022), Researchers Scan Brain of Dying Patient: Here’s What they Found, Healthline, available at: https://www healthline com/health-news/researchers-sca n-brain-of-dying-patient-heres-what-they-found#:~:tex t=A%20recording%20of%20a%20man's,and%20other%20t ypes%20of%20brainwaves (Accessed 15/11/24)
18 (2023), Death and the Brain, Medical Discovery News, Bridging the World of Medical Discovery and You, available at: https://www utmb edu/mdnews/podcast/episode/death-a nd-the-brain (Accessed 15/11/24)
19 Maryam Clark (2022) A Replay of Life: What happens in our brain when we die?’ Frontiers- Science news, available at: https://www frontiersin org/news/2022/02/22/what-happe ns-in-our-brain-when-we-die/ (Accessed 15/11/24)
20 Nathan A Shlobin, Jaan Aru, Raul Vicente, Ajmal Zemmar (2023) National Library of Medicine, PubMed Central, Frontiers in Aging Neuroscience, ‘What happens in the brain when we die? Deciphering the neurophysiology of the final moments in life,’ available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC10203241/ (Accessed 15/11/24)
process of dying can be curated, in both a biological and psychological sense
Further Research in Rats
Though brain scans have allowed us to get a valuable insight into what happens in the brain as we die, the research we have is still very limited. Therefore, to provide more thorough and intensive research, studies on rats have been conducted, specifically by Jimo Borjigin, a professor of neurology at the University of Michigan.21 When investigating the brain activity of rats when dying, she found that rats not only experience brain waves in a similar nature to humans, but also she also discovered that rats undergo a spike in the neurotransmitters dopamine and serotonin.22 This further research on rats allows us to get an accurate and more definite insight into what truly happens as one dies, as there is a flaw in the scans of the 87-year-old male previously mentioned, as the brain was swollen making observations unclear.23 Therefore, research on animals continues
21 Alex Basdel (2024) New research into the dying brain suggests the line between life and death may be less distinct than previously thought- ‘The new science of death: ‘There’s something happening in the brain that makes no sense,’ The Guardian, available at: https://www.theguardian.com/society/2024/apr/02/new-s cience-of-death-brain-activity-consciousness-near-deat h-experience#: :text=In%20her%20own%20laboratory%2 C%20she,and%20their%20brains%20lose%20oxygen (Accessed 19/11/24)
22 Alex Basdel (2024) New research into the dying brain suggests the line between life and death may be less distinct than previously thought- ‘The new science of death: ‘There’s something happening in the brain that makes no sense,’ The Guardian, available at: https://www theguardian com/society/2024/apr/02/new-s cience-of-death-brain-activity-consciousness-near-deat h-experience#:~:text=In%20her%20own%20laboratory%2 C%20she,and%20their%20brains%20lose%20oxygen (Accessed 19/11/24)
23 First-ever recording of a dying human brain shows waves similar to memory flashbacks, U of L, School of Medicine, available at: https://louisville edu/medicine/news/first-ever-recording -of-a-dying-human-brain-shows-waves-similar-to-me mory-flashbacks#: :text=What%20happens%20in%20our %20brain%20as%20we%20die%3F&text Imagine%20relivi ng%20your%20entire%20life,have%20a%20near%2Ddeath %20experience (Accessed 19/11/24)
to be conducted in order to achieve a better look at the post-humours brain
Limitations Of Brain Scan Evidence
In addition to the previously stated limitation of the scan, the research done on humans is only derived from very few studies meaning that it would be largely unwise to generalise these experiences for all humans and to make claims based on them.24 To extend on this, any other information gathered has been from individuals who have only experienced near-death experiences, not death itself, so to use information sourced from these individuals to explain and unpick the neuroscience of death would also be inaccurate
Revived brains
Though the newly grasped information of brain activity during the process is ground-breaking, the progression does not end there Recently, scientists have been able to revive activity in the brains of pigs from up to an hour after they were pronounced dead and circulation ceased 25 The process that made this possible was done at Yale University26 and entailed using a device by the name of BrainEx, to pump synthetic blood (containing oxygen and drugs) into the brain in
24 First-ever recording of a dying human brain shows waves similar to memory flashbacks, U of L, School of Medicine, available at: https://louisville edu/medicine/news/first-ever-recording -of-a-dying-human-brain-shows-waves-similar-to-me mory-flashbacks#:~:text What%20happens%20in%20our %20brain%20as%20we%20die%3F&text=Imagine%20relivi ng%20your%20entire%20life,have%20a%20near%2Ddeath %20experience (Accessed 19/11/24)
25 Michelle Starr (2024) ‘Scientists Revived a Pig’s Brain Nearly a Whole Hour After It Died’- Science Alert, available at: https://www sciencealert com/scientists-revived-a-pigsbrain-nearly-a-whole-hour-after-it-died#
26 James Gallagher (2019) ‘Pig brains partially revived four hours after death’ BBC- Health, available at: https://www.bbc.co.uk/news/health-47960874 (Accessed 19/11/24)
order to slow the death of brain cells. 27 Though this research is very promising, further research has found that there were not any indicators of brain wide electrical activity in an electroencephalogram, meaning that there is no evidence of cognitive function or awareness. 28 However, the brains did show signs of activity through showing normal and expected responses to medication that would be present in healthy and living subjects. 29
What this research tells us
Before this research was conducted, it was thought that brain-based cellular death was an irreversible process 30 However, this research directly contradicts this initial idea, leading to the discovery that neural cell integrity can be preserved after death and that it is possible to restore cell functionality 31 This astounding research has created territory for new discoveries in neuroscience to be explored and conducted, and to further investigate other processes that we believe to be impossible
How this research impacts medicine
These discoveries are not only beneficial to the world of science, but also to the medical field and treatments. Patients su ering from cardiac arrest
27 James Gallagher (2019) ‘Pig brains partially revived four hours after death’ BBC- Health, available at: https://www bbc co uk/news/health-47960874 (Accessed 19/11/24)
28 James Gallagher (2019) ‘Pig brains partially revived four hours after death’ BBC- Health, available at: https://www bbc co uk/news/health-47960874 (Accessed 19/11/24)
29 James Gallagher (2019) ‘Pig brains partially revived four hours after death’ BBC- Health, available at: https://www bbc co uk/news/health-47960874 (Accessed 19/11/24)
30 Bill Hathaway (2019) ‘Scientists restore some functions in a pig’s brain hours after death,’ Yale News, available at: https://news yale edu/2019/04/17/scientists-restore-some -functions-pigs-brain-hours-after-death (Accessed 19/11/24)
31 Bill Hathaway (2019) ‘Scientists restore some functions in a pig’s brain hours after death,’ Yale News, available at: https://news yale edu/2019/04/17/scientists-restore-some -functions-pigs-brain-hours-after-death (Accessed 19/11/24)
now have a much larger chance of survival due to the new-found ability to revive the brain following the arrest.32 As stated before, the process requires pumping blood into the brain, however this time uses the patient’s liver (to purify the blood) and a life support machine. 33 Therefore, research into the brain during and after death has proved to be enormously beneficial, ground-breaking and rewarding
32 Michelle Starr (2024) ‘Scientists Revived a Pig’s Brain Nearly a Whole Hour After It Died,’ Science Alert, available at: https://www sciencealert com/scientists-revived-a-pigsbrain-nearly-a-whole-hour-after-it-died# (Accessed 19/11/24)
33 Michelle Starr (2024) ‘Scientists Revived a Pig’s Brain Nearly a Whole Hour After It Died,’ Science Alert, available at: https://www sciencealert com/scientists-revived-a-pigsbrain-nearly-a-whole-hour-after-it-died# (Accessed 19/11/24)
An overview of the applications of psychedelic substances in the treatment of mental health conditions
By Lucia Amaral
Psychedelics are a class of psychoactive substances. Psychedelics are often thought of as causing hallucinations; however, they may also cause changes in an individual’s perception, cognitive processes, and mood 34 Recently, the interest in the applications of certain psychedelics as treatment for illnesses, specifically mental health disorders, has been growing within the medical and pharmaceutical community Many psychedelic compounds have been found to have anxiolytic e ects (can be used to alleviate anxiety), applications in treating addiction, uses as antidepressants and as a potential treatment for some chronic illness conditions Some psychoactive substances with possible therapeutic e ects include psilocybin (found in what are commonly known as ‘magic mushrooms’), Lysergic acid diethylamide (LSD) and dimethyltryptamine (DMT).
35 The specific influence psychedelic use has on a person is influenced by two factors i e their set, which is their internal state of mind and may be a ected by previous experiences using psychoactive substances, and their setting - their external surroundings. 1 When using psychedelics in a clinical setting, the individuals ‘set’ and ‘setting’ are controlled, and they are supervised by a medical professional. This results in minimal chances of a negative reaction to the substance For these reasons, it should be noted that although some psychedelic substances may have therapeutic e ects, they should not be taken outside of clinical settings as they may have harmful e ects on the individual. When taking Psychedelics some may
34 Alcohol and Drug Foundation (2021). PsychedelicsAlcohol and Drug Foundation [online] Alcohol and Drug Foundation Available at: https://adf org au/drug-facts/psychedelics/ [Accessed: 22 October 2024]
35 Meade, E , Hehir, S , Rowan, N and Garvey, M (2022) Mycotherapy: Potential of Fungal Bioactives for the Treatment of Mental Health Disorders and Morbidities of Chronic Pain Journal of Fungi, 8(3), p 290 doi: https://doi.org/10.3390/jof8030290. [Accessed: 22 October 2024]
experience what is known as a ‘bad trip’ which can cause the individual to feel extreme emotional distress or fear and may result in the person being in physical or emotional danger when not in a supervised, clinical setting 36
Magic Mushrooms and Psilocybin
The psychedelic compound found within magic mushrooms is psilocybin, which is produced by over 200 species of basidiomycetes fungi The psychedelic e ects of magic mushrooms are not in fact caused by psilocybin itself, but the digestive product of psilocybin- psilocin Psilocin stimulates serotonin 2A receptors on cortical pyramidal cells in the brain.37 These are neurons which are highly polarised and are the main excitatory neuron38 Activation of these receptors results in changes to metabolic activity in the brain and influences neural connections, thereby a ecting the person’s perception and neural functioning. Psilocybin has been found to alleviate symptoms of OCD, various addictions, and Alzheimer’s disease It also has a potential use as a long-lasting treatment for depression, as it has been found to last from 4 weeks to 6-12 months by various studies 4 Studies on the dosage and e ectiveness of the drug have proved it can be a successful treatment. When administered as a 25mg oral dose of pure
36 The Recovery Village Drug and Alcohol Rehab (n.d.). What Is a Bad Trip? | e Recovery Village. [online] Available at: https://www.therecoveryvillage.com/teen-addiction/what -is-a-bad-trip/ [Accessed: 30 October 2024]
37 Barron, M (2023) Psilocybin and Mental Health: e Magic in the Mushrooms [online] ASM org Available at: https://asm org/Articles/2023/February/Psilocybin-and-M ental-Health-The-Magic-in-the-Mush [Accessed: 25 October 2024]
38 www.sciencedirect.com. (n.d.). Pyramidal Cell - an overview | ScienceDirect Topics [online] Available at: https://www.sciencedirect.com/topics/neuroscience/pyra midal-cell [Accessed: 30 October 2024]
psilocybin with integrative psychotherapy it has been shown to alleviate depressive symptoms 39
Meade, E , Hehir, S , Rowan, N and Garvey, M (2022) Mycotherapy: Potential of Fungal Bioactives for the Treatment of Mental Health Disorders and Morbidities of Chronic Pain Journal of Fungi, 8(3), p 290 doi:https://doi org/10 3390/jof8030290
However, for those su ering with conditions such as schizophrenia and bipolar disorder, which are often co-morbid with depression, psilocybin ingestion could exacerbate psychosis 4 Physical health conditions such as heart and liver disease may also increase the risk of negative sidee ects 40 These may include intense confusion or fear, hallucinations, headache, high blood pressure, nausea, and paranoia 6
Ayahuasca
Ayahuasca (pronounced ah-yuh-wah-skuh ) is a brew that originates from the Amazonian basin and has been used for over 1,000 of years in spiritual ceremonies and for medicinal purposes Its name translates to “vine of the soul” in the Quechuan language Today ayahuasca is popular within ‘drug tourism’ and many travel to the Amazon to engage in ayahuasca ceremonies. The brew combines a
39 PSILOCYBIN: Overview, Uses, Side E ects, Precautions, Interactions, Dosing and Reviews (no date) www webmd com Available at: https://www webmd com/vitamins/ai/ingredientmono-16 54/psilocybin [Accessed: 22 October 2024]
40 Alcohol and Drug Foundation (2023) Magic mushrooms as medicine - Alcohol and Drug Foundation, adf.org.au. Available at: https://adf.org.au/insights/magic-mushrooms-medicine/. [Accessed: 22 October 2024]
strong source of the psychoactive ingredient dimethyltryptamine (DMT), contained in the Psychotria viridis shrub, with a plant containing monoamine oxidase inhibitors, called Banisteriopsis caapi, which prevents the stomach from breaking down DMT, facilitating the delivery its delivery to the brain. MAOIs block the active site of the enzyme that catalyses the breaking down of DMT (so act as a competitive inhibitor) preventing DMT binding
Similarly to psilocybin, DMT stimulates serotonin receptors in the brain, causing feelings of enhanced emotion and altered perception Brain imaging results have suggested ayahuasca reduces activity in the default mode network area of the brain, allowing the individual to observe their own thoughts without the judgement they usually place upon them, resulting in an emotionally healing experience It has also been suggested that MDT prompt growth and repair of neural cells, promoting neuroplasticity.
41
As with all psychedelics, ayahuasca comes with its own set of dangers. Interaction of ayahuasca with other medication including antidepressants, drugs for psychiatric conditions and weight loss drugs may pose dangers. The increase in heart rate and blood pressure caused by the brew may also be a health hazard for those with pre-existing heart conditions.42
For both psilocybin and ayahuasca many of the health benefits involve improving depressive symptoms. However, one apparent issue limiting their usefulness is that they may both pose risks to depression su erers with co-morbidities involving psychosis. A considerable proportion of schizophrenia patients also su er with depression (50%), therefore for these individuals’ psilocybin use would be harmful as it enhances psychosis in those predisposed to it Ayahuasca’s interaction with antidepressants means it is unusable for those
41 Sreenivas, S (2022) What Is Ayahuasca?, WebMD Available at: https://www webmd com/mental-health/addiction/what-i s-ayahuasca [Accessed: 30 October 2024]
42 Kubala, J. (2019) What Is Ayahuasca? Experience, Benefits, and Side E ects, Healthline Healthline Media Available at: https://www.healthline.com/nutrition/ayahuasca#takeaw ay [Accessed: 30 October 2024]
depression su erers who use antidepressants or would require them to halt their use Therefore, further research is needed to determine if there are alternative ways in which these substances can be used to aid these individuals
Treatment Resistance
Treatment resistance occurs when an adequate course of treatment does not elicit any response from the illness 43 Major treatments for depression and other neuropsychiatric diseases are based on prescription of antidepressants, some of the most common being SSRIs (selective serotonin reuptake inhibitors). These inhibit the reabsorption of serotonin by nerve endings, allowing the serotonin neurotransmitters to continue to stimulate the post-synaptic membrane, increasing the number of chemical messages sent down nerve cells However, for many mental- illness su erers these drugs may be ine ective, resulting in treatment resistance which a ects 30% of those diagnosed with depression 2
Through encouraging neuroplasticity by growth and repair of neural connections, psilocybin and MDMA (the synthetic drug 3,4-methylenedioxymethamphetamine, also known as ‘ecstasy’44) have both been useful in treatment of treatment-resistant depression. Psychedelic drugs do this by binding to the 5-hydroxytryptamine 2A receptors on neurons 45 During trials carried out over 3 weeks with patients su ering treatment resistant depression, a 25mg dose of Psilocybin was found to reduce depression scores significantly more than a 1mg dose. However, a 10mg dose was
43 Howes, O D , Thase, M E and Pillinger, T (2021) Treatment resistance in psychiatry: state of the art and new directions Molecular Psychiatry, [online] 27(1) doi: https://doi.org/10.1038/s41380-021-01200-3. [Accessed: 22 October 2024]
44 Abuse, N.I. on D. (2024). MDMA (Ecstasy/Molly) | National Institute on Drug Abuse (NIDA) [online] nida nih gov Available at: https://nida nih gov/research-topics/mdma-ecstasy-moll y [Accessed: 27 October 2024]
45 Reynolds, S (2023) How psychedelic drugs may help with depression [online] National Institutes of Health (NIH) Available at: https://www nih gov/news-events/nih-research-matters/ how-psychedelic-drugs-may-help-depression. [Accessed: 27 October 2024]
found to have little e ect. Although, the drug did result in negative side e ects 46
Overall, psychedelics may have strong implications in the future treatment of mental disorders, specifically anxiety disorders and depression However, these substances must be approached with caution as they can have disastrous e ects on the wellbeing of individuals when taken outside of clinical settings. They may also cause further harmful side e ects, such as exacerbation of pre-existing conditions, including psychosis It is important that the scientific community can explore the therapeutic e ects of psychedelics, removed from biases that have previously withheld research in this field. By o ering psychedelics as well researched, precisely formulated treatments, the prevalence of individuals choosing to use psychedelics unsafely themselves will likely decrease Uncontrolled substance use, often by treatment-resistant individuals who feel they have no other option to turn to, ultimately causes more harm than good
46 Goodwin, G M , Aaronson, S T , Alvarez, O , Arden, P C , Baker, A , Bennett, J C , Bird, C , Blom, R E , Brennan, C , Brusch, D , Burke, L , Campbell-Coker, K , Carhart-Harris, R , Cattell, J , Daniel, A , DeBattista, C , Dunlop, B W , Eisen, K , Feifel, D and Forbes, M (2022) Single-Dose Psilocybin for a Treatment-Resistant Episode of Major Depression. New England Journal of Medicine, [online] 387(18), pp 1637–1648 doi: https://doi.or1g/10.1056/nejmoa2206443. [Accessed: 31 October 2024]
Viewing Obesity as an Addiction
By Avnika Mittal
The Obesity Pandemic
In 2001, the WHO coined the term “globesity47” to refer to the global obesity epidemic - one of the most visible, yet most neglected, public health concerns in modern society. Obesity is the second-most prevalent cause of preventable illness across the globe today, closely following smoking48
Type II Diabetes, a range of cardiovascular diseases and cancers49 as well as multiple mental health disorders, can all be linked to obesity50 51 Additionally, treatment of this vast array of ailments is time-consuming and expensive to healthcare providers and governments; as of 2021, the estimated annual costs of obesity to the NHS was £19bil., with a further £16bil to wider society as a result of lower productivity52 . Given this, perhaps it is time for a new approach towards obesity prevention and management
47 Aetna International, ‘ The rise of globesity: a short introduction to a big problem,’ Aetna International [website], 2024, available at: https://www aetnainternational com/en/about-us/explore/h ealth-care/prevent-manage-conditions/the-rise-of-globesi ty html#:~:text=Tackling%20the%20problem,term%20“glob esity”%20in%202001. (accessed 09 June 2024).
48 Health Matters: Obesity and the Food Environment, GOV UK [website] , 2024, available at: https://www gov uk/government/publications/health-matter s-obesity-and-the-food-environment/health-matters-obesi ty-and-the-food-environment--2 (accessed 26 February 2024)
49 Controlling the global obesity epidemic (who.int) WHO not-for-profit, information cited and factual
50 Obesity, NHS [website], available at: https://www nhs uk/conditions/obesity/ (accessed 26 February 2024).
51 N M Petry , et al , (2008) Overweight and Obesity Are Associated With Psychiatric Disorders: Results from the National Epidemiologic Survey on Alcohol and Related Conditions Psychosomatic Medicine, 70(3), 288–297;
52 M Bell, et al , ‘The rising cost of Obesity in the UK,’ Frontier Economics [website], 21 November 2023, available at: https://www.frontier-economics.com/uk/en/news-and-insi ghts/news/news-article-i20358-the-rising-cost-of-obesityin-the-uk/#: :text=We%20estimated%20the%20total%20an nual,billion%20(see%20Figure%201) (accessed 09 June 2024)
In this article I will evaluate the extent to which it could be beneficial to view obesity in a similar manner to addiction
Obesity as a Disease
Although in theory obesity was first recognised as a disease by the WHO in 194853 , lack of consensus on diagnostic criteria and inconsistent methods of measurement meant that it is only recently being regarded as such, with the World Obesity Federation publishing their position statement in which they consider it a disease, in 2013. Also, whilst obesity is a risk factor for developing numerous condition from Type II diabetes to coronary heart disease, living with obesity does not guarantee the individual will su er other poor health outcomes, and equally not all who su er these poor health outcomes may be obese; one of the criticisms of terming obesity a disease is that rather than being a disease itself, without comorbidities it si not necessarily harmful of itself Reluctance to term it as such also stems from the possibility that, rather than decreasing weight stigma, doing so may increase weight discrimination and associated healthcare inequalities, or concerns that this may lead the public to feel less inclined to heed preventative lifestyle guidelines, instead relying on medical intervention World Obesity responds to these concerns by arguing,
‘that defining obesity as a disease does not lessen but rather increases society’s responsibility to prevent excess weight gain through a range of population-wide interventions to promote optimum health Such population-wide measures are not only preventive but are also integral to the treatment process, reducing the risk of weight
53W P James, ‘WHO recognition of the global obesity epidemic,’ Int J Obes (Lond). December 2008;32 Suppl 7:S120-6 doi: 10 1038/ijo 2008 247 PMID: 19136980
regain for people who have successfully lost weight54 ’
In response to concerns of this definition increasing weight stigma, World Obesity have said,
‘a medical diagnosis can help to reduce a person’s internalised stigma or belief that their excess weight is entirely self-inflicted and shameful. It may change the public discourse about blame for the condition [and] alter perceptions in the healthcare services, encouraging greater empathy with patients55 . ’
In their response, the World Obesity Federation gave the example that society is unlikely to blame an individual with heart disease or cancer for their condition, however one may find this is not necessarily always true We may, perhaps unjustly, blame a smoker with either or both of these for their ailment, though one could argue that we may be less inclined to blame this smoker for their substance addiction, for addiction is recognised to be the result of a disorder, entirely out of the su erer’s control, and is a disease frequently exploited for a profit by various industries This is part of the reason it has been argue that it could be beneficial to view obesity in a similar manner to addiction, not least because there is mounting evidence of overlapping neural pathways between the two56 57 To evaluate this however, we must first understand addiction
54 ‘Obesity as a disease,’ World Obesity Federation [website], available from: https://www.worldobesity.org/what-we-do/our-policy-prio rities/obesity-as-a-disease (accessed 27 November 2024)Published in a reputable journal, no known conflicts of interest
55 ‘Obesity as a disease,’ World Obesity Federation [website], available from: https://www.worldobesity.org/what-we-do/our-policy-prio rities/obesity-as-a-disease (accessed 27 November 2024)
56 A Michaud, ‘Overlapping Neural Endophenotypes in Addiction and Obesity,’ Frontiers Endocrinology, 14 June 2017, Vol 8 - 2017 https://doi org/10 3389/fendo 2017 00127
57 V. H. Taylor, C. M Curtis, & C. Davis, (2010), ‘The obesity epidemic: the role of addiction,’ CMAJ : Canadian Medical Association journal journal de l'Association medicale canadienne, 182(4), 327–328 https://doi org/10 1503/cmaj 091142
Obesity as a Disorder of Addiction
Although sedentary lifestyles have often been suggested to be the driving cause for globally rising rates of obesity, it is now generally agreed that increased physical activity does little to increase caloric expenditure58 59 , rather is beneficial because we burn a largely preset amount of calories daily so exercise uses calories that might otherwise be involved in stress and inflammatory response60 61 In recent years it has begun to be agreed that obesity is largely the result of overconsumption, that is increased caloric intake rather than a reduction in expenditure. Often the foods most commonly associated with driving this overconsumption are ultra-processed foods (UPF). These are thought to drive over consumption for three primary reasons:
- UPF is soft, dry and energy dense62
As a result we consume UPF products much faster than we would whole foods; when we eat UPF, we obtain far more calories from it in a much shorter space of time than we would from whole food UPF interferes with homeostatic mechanisms to regulate energy intake and expenditure so UPF consumption leaves us feeling hungry and dissatisfied, associated with overconsumption
- Additives drive excess consumption. Additives commonly used to increase palatability of UPF mimic beneficial molecules without providing their benefits It has been suggested that the disconnect caused by these prevalent additives and artificial flavourings - provoking a sensation associated with a given beneficial molecule which is
58H Pontzer, et al , “Energy expenditure and activity among Hadza hunter-gatherers.” American journal of human biology : the o cial journal of the Human Biology Council vol 27,5 (2015): 628-37. doi:10.1002/ajhb.22711
59 H Pontzer, et al , ‘Hunter-gatherer energetics and human obesity ’ PloS one vol 7,7 (2012): e40503 doi:10 1371/journal pone 0040503
60 A Sharma, V Madaan & F D Petty ‘Exercise for mental health,’ Primary care companion to the Journal of clinical psychiatry, (2006), 8(2), 106
61K. Mikkelsen, et al., ‘Exercise and mental health.’ Maturitas, 01 December 2017;106: 48-56
62C. A. Monteiro, E. Martinez-Steele, G. Cannon, ‘Reasons to avoid ultra-processed foods,’ BMJ 2024;384:q439
not, in fact, present - is a large factor in driving excess consumption, ultimately leading to obesity63 It has been suggested that perhaps the reason low-carb diets appear e ective is that often, high-sugar foods are UPF so following a low-carb diet may indirectly result in reduced UPF in one’s diet64
- UPF is designed to be addictive65 . Created as a means of adding marketing value to agricultural and other industrial waste, UPF is not designed with potential benefits to public health in mind66 . It is designed to drive overconsumption to increase manufacturers’ profits, and this overconsumption is driven by the foods which we most frequently have access to impairing neuroendocrine systems which ought otherwise to regulate our energy intake and expenditure67 It has been suggested that, in a similar manner to addictive substances interfering with systems of reward in the brain, UPF too interferes with serotonergic and dopaminergic responses68 suggesting obesity could be viewed as a substance, rather than exclusively behavioral addiction.
Considering obesity in a similar manner to addiction, one may argue, could provide a stronger counter-argument to the criticisms of its
63 ‘The Harsh Reality of Ultra Processed Food,’ e Royal Institution [podcast], presentation by Chris Van Tulleken, December 2023, https://www youtube com/watch?v=5QOTBreQaIk (accessed 26 February 2024)
64 C. V. Tulleken, Ultra Processed People (Penguin 2023)
65 N D Volkow, et al , ‘Overlapping neuronal circuits in human obesity and addiction,’ Philosophical Transactions of the Royal Society B, 2008;363:3191-200
66 K Chang, et al , ‘Association between childhood consumption of ultra processed food and adiposity trajectories in the Avon Longitudinal Study of Parents and Children birth cohort JAMA Paediatrics 2021; 175; e211573
67 H. Kober, & R. Boswell, ‘Potential psychological & neural mechanisms in binge eating disorder: Implications for treatment,’ Clinical Psychology Review, 2018;60: 32–44
68 O Contreras-Rodriguez, M Solanas, & R M Escorihuela, (2022). ‘Dissecting ultra-processed foods and drinks: Do they have a potential to impact the brain?’ Reviews in endocrine & metabolic disorders, 23(4), 697–717. https://doi org/10 1007/s11154-022-09711-2
classification as a disease, for the most e ective means of addiction management are through guidance to aid prevention, and through lifestyle interventions rather than immediate medical treatment. Further, with addiction being a disorder entirely out of the individual’s control, it may be easier to hold accountable those who propagate weight discrimination as well as preventing such discrimination from increasing health inequalities69 Working to eradicate health inequalities is of particular importance in the case of overweight and obesity particularly since these are conditions which increasingly most disproportionately a ect the most disadvantaged of society
69 R. Friedman, & R. Puhl, (2012), ‘Rudd report: weight bias as a social justice issue,’ available at: http://www uconnruddcenter org/files/Pdfs/Rudd Policy Brief W eight Bias pdf
Stem Cell Treatments in Paediatric Cancers
By Olivia Barrow
Stem Cell Treatment Overview
Stem cells are undi erentiated cells which can undergo di erentiation to form a cell that is designed to perform a specific function Stem cells can be found in adult bone marrow and in embryos
The most common stem cell treatment is a stem cell transplant. Stem cell transplants involve destroying any blood cells that are either damaged or unhealthy by replacing them with blood cells from the bone marrow or that have been removed from the blood. The three types of blood cell are: red blood cells (which are responsible for the transportation of oxygen in the bloodstream), white blood cells (which are part of the immune system and are responsible for fighting disease), and platelets (which are needed for the blood to clot to stop excessive bleeding) 70
How Stem Cell Transplants Work
There are two types of stem cell transplants: autologous transplants and allogeneic transplants.71
Autologous stem cell transplants use the child’s own healthy stem cells to treat cancers that would require high doses of chemotherapy such as Ewing’s Sarcoma, neuroblastoma, Hodgkin’s Lymphoma, and medulloblastoma 72 The stem cells
70 ‘Stem Cell and bone marrow transplants’ NHS [website] available at: https://www.nhs.uk/conditions/stem-cell-transplant/ (accessed 3 November 2024)
71 ‘Stem Cell Transplantation – Cancer Treatment’ Children with Cancer UK [website] available at: https://www childrenwithcancer org uk/childhood-cancer -info/understanding-cancer/treatments/stem-cell-trans plant/ (accessed 30 October 2024)
72 P Tewari, M D ‘Pediatric stem cell transplants: What to know’ e University of Texas, MD Anderson Cancer Center [website] available at: https://www mdanderson org/cancerwise/pediatric-stem -cell-transplants--what-to-know.h00-159382734.html (accessed 30 October 2024)
are harvested from the bloodstream of the patient (these stem cells are known as peripheral blood stem cells).73
Allogeneic stem cell transplants use stem cells from a donor. The transplant also requires a course of high-dose chemotherapy prior to the transplant The donor stem cells can di erentiate into new immune cells that work with the body to treat the foreign cancer cells 74 Prior to the transplant, the patient will endure a conditioning treatment that consists of chemotherapy and/or radiation to destroy any remaining cancer cells and to also weaken the patient’s immune system, so the donor cells are less likely to be rejected.75
Risks and Side e ects of Stem Cell Treatments
The side e ects in stem cell treatments are often typically caused by the chemotherapy or the use of any additional targeted drugs that are taken alongside the treatment If a patient undergoes an allogenic transplant, the patient has a risk of developing a disease known as ‘graft versus host’ disease (GvHD). This is because the transplanted cells contain immune cells from the donor which can attack the patient’s healthy body cells.
Due to the weakened immune system of a patient because of the conditioning treatment, there is
73 M Markman, M D ‘Autologous stem cell transplant’ City of Hope [website] available at: https://www cancercenter com/treatment-options/hemat ologic-oncology/autologus-stem-cell-transplant (accessed 30 October 2024)
74 ‘Stem cell transplants’ Lymphoma Action [website] available at: https://lymphoma-action org uk/about-lymphoma-treat ment-lymphoma/stem-cell-transplants (accessed 30 October 2024)
75 ‘Allogeneic Stem Cell Transplantation’ Leukaemia and Lymphoma Society [website] available at: https://www lls org/treatment/types-treatment/stem-cell -transplantation/allogeneic-stem-cell-transplantation (accessed 3 November 2024)
always a high risk of infection. This can be reduced using antibiotics, antifungal medicines, and mouthwashes.
A patient may need to follow a specific diet due to the risk of infection in food Precautions may need to be taken such as washing all fruit and vegetables and avoiding lightly cooked eggs and soft cheeses
After stem transplants, it is common to lose immunity to diseases that are often vaccinated against as a child Therefore, it is important for patients to contact their doctor to understand what diseases they must be re-vaccinated against
There is also an increased risk of anaemia due to a low red blood cell count There may also be an increased risk of bleeding.
A longer-term risk of stem cell treatment is infertility This can be caused by the high doses of chemotherapy a patient is required to endure as part of their treatment, or because of radiation treatment which can cause total body irradiation.76
Specific Study: Paediatric Leukaemia
Leukaemia is a form of cancer that begins in cells that would typically develop into blood cells Leukaemia commonly develops in white blood cells, but it can develop in other blood cell types too 77
Leukaemia is the most common cancer in children under the age of 15 In the UK, each year, over 650 children and adolescents are diagnosed with a
form of leukaemia. The most common type of leukaemia is acute lymphoblastic leukaemia (ALL) 78
Patient X was first diagnosed with leukaemia at two years old. He underwent treatment and his cancer was brought into remission Patient X’s mother fell pregnant and being aware of the risk of a relapse in Patient X’s health, she decided to bank the baby’s cord blood. When Patient X was five and a half years old, he relapsed with leukaemia This brought his chance of survival to 50%. The new treatment plan for Patient X’s leukaemia was a transplant Thankfully, due to the storage of Patient X’s sibling’s cord blood, the stem cells were readily available for use in treatment Once again, Patient X went into remission and has been cancer-free ever since
In siblings, bone marrow stem cells have a 25% chance of being a match whereas cord blood stem cells have a 50% chance of being a match. For patients who use cord blood stem cells from a sibling, their one-year survival rate was approximately 63%. However, for patients who use donor cord blood stem cells, their one-year survival rate is 29%.79
Specific Study: Pediatric Neuroblastoma
Neuroblastoma is a form of cancer that e ects the specialist nerve cells (known as neural crest cells). These nerve cells are pivotal in the development of the sympathetic nervous system and other tissues. Neuroblastoma commonly occurs in the abdomen, close to the kidneys, in one of the adrenal glands. However, it can also occur in nervous tissue along the spinal cord in the neck, chest, abdomen, or
76 ‘Side e ects of a stem cell or bone marrow transplant’ Cancer Research UK [website] available at: https://www cancerresearchuk org/about-cancer/treatme nt/bone-marrow-stem-cell-transplants/side-e ects (accessed 3 November 2024)
77 ‘What is Childhood Leukaemia?’ American Cancer Society [website] available at: https://www cancer org/cancer/types/leukemia-in-childr en/about/what-is-childhood-leukemia.html (accessed 3 November 2024)
78 ‘Childhood Leukaemia’ Blood Cancer UK [website] available at: https://bloodcancer org uk/understanding-blood-cancer/l eukaemia/childhood-leukaemia/ (accessed 3 November 2024)
79 ‘Cord Blood Stem Cells Treat Brother’s Leukaemia’ Cells4Life [website] available at: https://cells4life.com/project/cord-blood-stem-cells-trea t-brothers-leukaemia/ (accessed 3 November 2024)
pelvis as it spreads through the blood and lymphatic system 80
Neuroblastoma is one of the most common forms of an embryonal tumour. An embryonal tumour is one which is categorised by the proliferation (rapid increase) of tissue which is typically found in developing embryos Therefore, neuroblastoma is commonly diagnosed in children under five, and it is very rare in children over ten 81
Patient Y was born in 2002 when the concept of cord blood banking was new and inventive. Despite this, Patient Y’s family decided to bank their cord blood. Four years later, Patient Y was diagnosed with Stage 4 Neuroblastoma and was advised to pursue palliative care and return home due to how advanced their cancer was However, Patient Y opted against this and chose to endure treatment. Patient Y underwent six cycles of radiotherapy and chemotherapy as well as an eight-hour surgery to remove the tumour which had been caused by the Neuroblastoma Following this, Patient Y received a bone marrow transplant to help replace their damaged stem cells and then they received their cord blood to help strengthen their immune system by reintroducing their own stem cells into their body. Patient Y went into remission in 2008.82
Paediatric Oncology: Alternative Treatment Developments
Severe brain cancer in children is often fatal, with most surviving up to a year after diagnosis. Members of the ‘Cancer Research UK Children’s Brain Tumour Centre of Excellence’ in Cambridge
80 ‘What is Neuroblastoma?’ Cancer Research UK [website] available at:
https://www cancerresearchuk org/about-cancer/childre ns-cancer/neuroblastoma/about (accessed 12 November 2024)
81 ‘Neuroblastoma’ Children with Cancer UK [website] available at:
https://www childrenwithcancer org uk/childhood-cancer -info/cancer-types/neuroblastoma/#what-is-neuroblasto ma (accessed 3 November 2024)
82 ‘Cord Blood Stem Cells Treat Neuroblastoma’ Cells4Life [website] available at: https://cells4life.com/project/cord-blood-stem-cells-trea t-neuroblastoma/ (accessed 12 November 2024)
are currently experimenting the use of artificial intelligence (AI) in the treatment of brain cancer By creating digital models of complex and severe brain tumours, the team are aiming to find treatments which are safer and gentler for use in children.83
Additionally, the University of Manchester and the Christie cancer hospital have designed a project to assess the e ectiveness of radiotherapy on digital patients. The virtual patients have been created using AI, which was based on real-life data The aims of the University of Manchester are to investigate patient genetics and tumours. Also, they are aiming to compare proton beam therapy with the standard, traditional radiotherapy in the treatment of lung cancer 84
83 ‘Could AI help treat brain tumours in children’ BBC News [website] available at: https://www bbc co uk/news/articles/cp3w35jd1gqo (accessed 12 November 2024)
84 ‘Scientists use AI to mimic cancer patient trials’ BBC News [website] available at: https://www bbc co uk/news/articles/cew200d79nlo (accessed 12 November 2024)
How Stem Cells Could Change the Face of Medicine
By Elizabeth Lyon
What are stem cells85?
Stem cells are a special, very important type of cell for two primary reasons: they have not di erentiated yet and they can replicate themselves very quickly. The most common type of stem cell is embryonic, those of foetuses, whilst adult stem cells are found in the bone marrow. Embryonic stem cells are the most versatile as they can develop into any type of cell but there is an ethical issue. This stems from the fact that these foetuses that are used have the capacity to become human life. Some people would argue that because the majority of the embryonic stem cells come from IVF facilities the cell should be used to treat people because if not they would be thrown away But the embryos have to be destroyed in order for the research to take place, which makes some people believe we are harming human life
Stem cell transplants86 87
Stem cell transplants are not done often, usually when all other options have not helped the patient A stem cell transplant can involve taking a healthy stem cell from the blood or bone marrow of one person, ideally a close family member, and transferring them to another person This is called allogenic transplant It is also possible to remove stem cells from your own body and transplant them later after any damaged or diseased cells have been removed, thus it is called autologous transplant. A stem cell transplant has 5 main stages: test and examinations to assess your general level of health; harvesting; conditioning treatment using chemotherapy or radiotherapy; and
85Y Brazier, (2018) Stem cells: Sources, types, and Uses [online] Medical News Today Available at: https://www medicalnewstoday com/articles/323343
86NHS (2019) Overview - Stem cell and bone marrow transplants [online] NHS Available at: https://www nhs uk/conditions/stem-cell-transplant/
87Mayo Clinic Sta (2024). Stem cells: What they are and what they do [online] Mayo Clinic Available at: https://www.mayoclinic.org/tests-procedures/bone-marro w-transplant/in-depth/stem-cells/art-20048117
transplanting the cells into the patients Stem cell transplants are most used to treat severe aplastic anaemia (bone marrow failure), leukaemia, lymphoma, multiple myeloma, immune system disorders and metabolic disorders Although they could be used in multiple other areas of medicine including organ transplants, people who are paralysed and cancer treatments While stem cell use may sound amazing in theory, there are some risks as it is an extremely complicated procedure Potential problems are graft versus host disease which happens in allogeneic transplants when the stem cells start to attack other cells It can also reduce the number of blood cells which may lead to an iron deficiency, excessive bleeding or bruising, and an increased risk of infection. You may also experience side e ects common to people having chemotherapy.
Harvesting of stem cells for transplants88
89 90
Firstly, the person who is donating the stem cells are tested to ensure that they are healthy enough to be used in the procedure. A common test health care professionals use is an electrocardiogram to look at their heart and electrical activity They also use echocardiograms to look at blood vessels, X-rays, and blood tests After that the cells are harvested There are three main ways that stem cells can be harvested. The first is from blood from bone marrow, usually taken from the hip bone, and from cord blood, this is where blood is donated from the placenta and
88NHS (2019) What happens - Stem cell and bone marrow transplants [online] NHS Available at: https://www nhs uk/conditions/stem-cell-transplant/whathappens/
89NHS Choices (2019) Risks - Stem Cell and Bone Marrow Transplants [online] NHS Available at: https://www.nhs.uk/conditions/stem-cell-transplant/risks/.
90Y Brazier, (2018) Stem cells: Sources, types, and Uses [online] Medical News Today. Available at: https://www medicalnewstoday com/articles/323343
umbilical cord of a new-born baby. Then they will move on to conditioning treatment with high doses of chemotherapy and sometimes radiotherapy. This is to destroy existing bone marrow cells, destroy any cancer cells and to stop your immune system from working. This reduces the risk of the transplant being rejected Finally, the transplant will usually be carried out a day or two after conditioning has finished and the stem cells will be passed slowly into your body through the central line. This process usually takes a couple of hours Once the transplant has finished it is mandatory that you stay in hospital for a few weeks while you wait for the stem cells to settle into your bone marrow and start producing new cells. During recovery the patient may feel weakness, vomiting and loss of appetite Number of red blood cells and platelets may decrease, and the patient will have to stay in a germ free room due to low white blood cells
Uses of stem cells for organ transplants91 92
The reason so many scientists are so interested in stem cells is because they could regenerate the organ it came from entirely Some scientists have suggested injecting stem cells into organs that are failing, for example liver cells, and the stem cells will turn into liver cells and fix what is going wrong. Other medical professionals have said that you could take some of the stem cells from the patient and grow the failing organ from them. This would be ground-breaking as it would stop the risk of rejection all together as it would be your own cells. It would also decrease the transplant waiting list as patients would not have to wait as long for the organ they need. The only problem is that the organs would have to be made in animal host This has been tested using cattle and pigs. Despite the potential of using embryonic stem cells, you cannot make mistakes and making the
91L Amjal, et al , (2023) Organ Regeneration Through Stem Cells and Tissue Engineering Cureus, [online] 15(1) doi: https://doi.org/10.7759/cureus.34336.
92 Cleveland Clinic (2023) Stem Cells: Medicine’s New Horizon [online] Cleveland Clinic. Available at: https://my clevelandclinic org/health/body/24892-stem-cells
organs can be slow. This is also a very controversial topic as some people would argue that this is animal cruelty as the animals have to host the new organ and taking the organ out of the body could have many complications for the animal. On the other hand, some would argue that it is necessary to do this in order to save a large population of humans from risking rejections and spending years on the transplant list
Are stem cells worth it?
The decrease of risk in transplant surgeries due to stem cell use is why they have the ability to change the face of medicine They can be used in multiple fields, such as cancer treatment, peripheral neuropathy and transplants. There are ethical issues that object to this, but with more funding scientists would be able to come up with a solution to the problem As stem cells become more widely used in the medical field these cells can save the lives of millions of people and drastically improve their quality of life
Innovative Organoids
By Alfie Lumb
Introduction
There’s an underappreciated innovation currently occurring in medical science that’s flying under everyone’s radar. They’re called organoids.
Harvard’s stem cell institute described organoids as ‘a new window into disease, development and discovery.’93
Simply put, organoids are small parts of organs or cell tissues manufactured in a lab from stem cells. They can be used in cancer research and to replace dysfunctional tissues via surgery
But what are they, and how are they made?
In tumour research, tumour cells are used to derive organoids Therefore, to say all organoids are derived from stem cells is technically wrong. However, most organoids used in research applications are derived from stem cells
These stem cells come in two forms: ASC - Adult derived stem cell or iPSC - Induced pluripotent stem cell derived organoids (which are adult cells reprogrammed to be like embryonic cells)
They are made by firstly deriving organoids from (stem) cells which are then placed in a specific, manufactured environment to stimulate the growth of a desired cell(s) used to replicate parts of an organ. One way to stimulate di erentiation is by using nanotopography (really small bumps of certain materials). The arrangement and frequency of materials contributes to di erentiation but it is much more complex than that.
“Nanotopography, What’s that?”
Nanotopography is a multi step process to promote di erentiation of stem cells The five steps that commonly occur are:
1 Cell extraction, where stem cells are extracted from a relevant tissue (likely adult bone marrow or embryos)
2. Nanotopography, where growth factors and ‘small molecules’ are added to a dimpled plate along with the extracted cells
3. Immature, di erentiated cells are then placed in ExtraCellular Matrix (ECM) which provides ‘biochemical cues and structural support’94 and increases variability of stem cells
4 Physical cues are provided which ‘mimic the nutrient and waste di usion of the basement membrane’95 The basement membrane connects the cells to the ECM and provides mechanical support for di erentiation.
5. Addition of engineered organ substructures (OOC - Organ On a Chip) which mimic the physiology of the cell being studied and interconnect multiple cells to mimic larger organ structures.
What are they used for?
Organoids have many uses, such as: to treat diseases like epilepsy and to study the growth and development of tumours to further research of cancers. Furthermore, as organoids can be made to replicate organs, they may also be able to be used in
93Organoids: A new window into disease, development and Discovery (2017) Harvard Stem Cell Institute (HSCI).
Available at: https://hsci harvard edu/organoids (Accessed: 19 November 2024)
94Corning® Matrigel® Matrix for organoids | disease modelling and drug discovery | corning Available at: https://www corning com/worldwide/en/products/life-scien ces/products/surfaces/matrigel-matrix-for-organoids.html (Accessed: 11 November 2024)
95 Zhao, Z. et al. (2022) ‘Organoids’, Nature Reviews Methods Primers, 2(1) doi:10 1038/s43586-022-00174-y
surgeries to replace dysfunctional tissues, as well as being used to study the e ects and e cacy of drugs
As you can see, organoids have a multitude of uses This vast applicability enables such a small thing to be used in massive, world-changing ways.
However, there are some problems plaguing organoid research When studying cerebral organoids, huge ethical concerns are raised about consciousness
Using iPSCs scientists created a cerebral organoid that developed optic cups (the early formations of a retina) after 50 days. When exposed to light, the organoid showed responsive electrical activity in its neurons.
This response provides many questions into whether these structures can be classed as having a conscience. Furthermore, when terminated, can they feel pain and experience su ering?
Another issue with organoid research is whether the findings can be directly applied to human’s vastly more complex body systems. In the future, this may lead to the demand for the development of more complex organoids to create more direct correlations between the e cacy of medicines on organoids to humans.
In summary, Organoids have many, incredible uses that can undoubtedly further many fields of medicine, yet they are held back by ethical concerns No doubt, as medical science and research continues to progress, the demand for more complex structures will increase and bring with it greater ethical concerns which will require significant attention and restrictions
Digital Dentistry and Tele-dentistry: Revolutionising Oral Healthcare
By Thomas Leonard
The dental field is undergoing a remarkable transformation, fuelled by advancements in digital dentistry and tele-dentistry These innovative technologies are reshaping the way oral healthcare is delivered, enhancing accessibility, precision, and e ciency. This article explores the scope, benefits, challenges, and future potential of these developments, supported by real-world examples and research
Understanding Digital Dentistry
Digital dentistry refers to the integration of advanced digital tools and technologies into dental practices. It encompasses innovations such as Computer-Aided Design and Manufacturing (CAD/CAM), which are used to create highly precise dental restorations like crowns and bridges Similarly, 3D printing is revolutionising prosthodontics and orthodontics, enabling the production of customised aligners, dentures, and surgical guides.
Another significant development in digital dentistry is the use of advanced imaging tools such as cone-beam computed tomography (CBCT) and intraoral scanners. These technologies provide detailed visualisations of the oral cavity, improving diagnostics and treatment planning. Artificial intelligence (AI) is also making its mark by detecting dental pathologies, predicting treatment outcomes, and personalising care Augmented and virtual reality (AR/VR) enhance training for dental professionals and o er immersive educational experiences for patients.
These advancements collectively improve accuracy, streamline procedures, reduce treatment times, and boost patient satisfaction, setting new standards in oral healthcare.
Applications of Digital Dentistry
Digital dentistry has revolutionised diagnostics by providing highly detailed, three-dimensional views of oral structures This allows for the early
detection of conditions such as cavities, periodontal disease, and oral cancer For instance, CBCT scans are invaluable for precise implant placements and the management of complex cases.
Restorative procedures have also become more e cient. CAD/CAM systems drop the need for traditional impressions, which are often uncomfortable for patients, allowing dentists to design and fabricate restorations during a single visit Additionally, orthodontics has been transformed through innovations like clear aligners Companies such as Invisalign employ 3D scanning and printing to create custom aligners, providing patients with a comfortable and e ective way to straighten their teeth.
The Emergence of Tele-dentistry
Tele-dentistry, which involves using telecommunications technology to deliver dental care remotely, has gained significant traction, particularly during the COVID-19 pandemic It includes live video consultations, mobile health applications that provide oral health education and self-management tools, and the exchange of diagnostic data between patients and dentists.
While tele-dentistry cannot entirely replace in-person care, it complements traditional methods by making dental services more accessible and enabling early intervention Patients in remote or underserved areas can consult with dentists and access treatment recommendations without the need for travel, significantly improving their oral healthcare experience.96
Advantages of Digital Dentistry and Tele-dentistry
The adoption of digital dentistry and tele-dentistry o ers many benefits Tele-dentistry removes
96 Dawood, A., Marti Marti, B., Sauret-Jackson, V., & Darwood, A (2015) 3D Printing in Dentistry British Dental Journal, 219(11), 521-529
geographical barriers, allowing patients in rural or remote regions to access care that would otherwise be unavailable Meanwhile, digital tools improve patient comfort by replacing traditional methods, such as messy impressions, with modern, streamlined alternatives. These innovations also save patients time and money by reducing the need for travel and enabling faster, more e cient treatments 97
Advanced imaging and AI-powered diagnostics further enhance care by detecting dental issues early, which prevents complications and reduces the need for extensive interventions In practice, digital and tele-dentistry have been successfully applied in outreach programs in countries like the United States and India. For example, mobile units equipped with digital tools bring diagnostic services to underserved populations, while remote consultations with specialists are conducted to guide treatment Companies such as SmileDirectClub and Candid have also used tele-dentistry and 3D printing to make orthodontic care more a ordable and accessible.98
Challenges and Limitations
Despite their promise, digital dentistry and tele-dentistry face several challenges. High first costs for equipment, software, and training can be prohibitive for smaller practices Additionally, there is a technological learning curve for dental professionals, requiring considerable time and e ort to master new systems.
Access to technology also poses a barrier Not all patients or providers have access to the necessary devices or reliable internet connectivity, limiting the reach of these innovations. Furthermore, remote consultations may lack the nuance of in-person care, and some conditions still require physical examinations to ensure accurate diagnosis and treatment
The Future of Oral Healthcare
Digital dentistry and tele-dentistry are revolutionising oral healthcare, and their potential is only beginning to be realised Although challenges such as costs and accessibility remain, continued advancements in technology and greater adoption are likely to overcome these barriers. By embracing these innovations, dental professionals can improve care quality, enhance patient outcomes, and extend services to underserved populations
The integration of digital tools with remote care platforms heralds a more connected, patient-centred approach to oral health As these technologies evolve, they promise to create a future where dental care is more precise, e cient, and accessible than ever before.99
97 Estai, M , & Kruger, E (2018) Teledentistry as a Model for the Provision of Oral Health Care to Rural and Remote Populations: A Systematic Review. Journal of Evidence-Based Dental Practice, 18(4), 304-312
98 Schwendicke, F , Samek, W , & Krois, J (2020) Artificial Intelligence in Dentistry: Chances and Challenges Journal of Dental Research, 99(7), 769-774
99 Joda, T , Waltimo, T , Pauli-Magnus, C , & Probst-Hensch, N (2020) Advances in Digital Dentistry
The Human Genome Project
By Chloe McCreedy
1100
Overview
The Human Genome Project (THGP) was an extensive study beginning October 1990 and concluding April 2003. THGP is considered one of the greatest achievements in science, led by international researchers. This feat’s goal was to create the first ever sequence of the human genome.101 A genome is the entire set of DNA instructions found in a cell The genome is located in the nucleus of cells and, in the case of humans, it consists of 23 pairs of chromosomes102 (22 pairs of autosomes and 1 pair of sex chromosomes) 103
Methodology and Timeline
The original goal in 1988 was to map out the entire human genome as well as other non-human organisms’ By the end of the project, genomes had
100 Wikipedia Contributors (2019). Human Genome Project. [online] Wikipedia Available at: https://en.wikipedia.org/wiki/Human Genome Project [Accessed: 12 November 2024]
101 National Human Genome Research Institute (2020). e Human Genome Project [online] National Human Genome Research Institute. Available at: https://www genome gov/human-genome-project [Accessed: 12 November 2024]
102 Green, E (2019) Genome [online] Genome gov Available at: https://www genome gov/genetics-glossary/Genome [Accessed: 17 November 2024]
103 Sarah A. Bates (2019). Chromosome. [online] Genome gov Available at: https://www.genome.gov/genetics-glossary/Chromosome [Accessed: 18 November 2024]
been sequenced for E. coli, baker’s yeast, fruit fly, nematode and mouse THGP clearly exceeded its original goals and in fact was completed 2 years earlier than predicted
The sample from which the human genome was mapped came from 20 people, but their identities are unknown to ensure their privacy and protection. The majority of the mapped sequence originated from just one person of blended ancestry and the rest from 19 people of European ancestry The volunteers were recruited via advertisements (like the one below) and blood samples were collected
DNA sequencing, specifically Sanger DNA sequencing, was the primary tool for mapping the human genome This process involves establishing the precise order of DNA bases (i.e. A, C, G and T) 104 These DNA nucleotide bases (adenine, cytosine, guanine, thymine), if complementary, form base pairs These pairs are the structure for the double-helix shape found in DNA and connect the 2 separate strands via hydrogen bonds to embody a twisted ladder. Adenine and thymine pair together and cytosine pairs with guanine The human genome is composed of 3 billion base pairs,
104 National Human Genome Research Institute (2022) Human Genome Project [online] National Human Genome Research Institute. Available at: https://www genome gov/about-genomics/educational-re sources/fact-sheets/human-genome-project [Accessed: 20 November 2024]
Figure
Figure 25
spread across 23 chromosomes of varying sizes: 50 million to 300 million 105
Sanger DNA sequencing was developed by Frederick Sanger (a two-time Nobel Laureate) and his colleagues in 1977 It is otherwise known as the “chain termination method” and determines the nucleotide sequence of DNA Sanger DNA sequencing follows 3 stages:
1. DNA Sequence for Chain Termination PCR
The chosen section of DNA is amplified and denatured using standard PCR, but chain termination di ers in the extension phase. Modified nucleotides called dideoxyribonucleotides (ddNTPs), which are chain-terminating, are mixed with normal deoxynucleotide triphosphates (dNTPs).
There are 4 types of dNTPs (unmodified) and ddNTPs (modified): dATP/ddATP – adenosine, dTTP/ddTTP – thymine, dGTP/ddGTP – guanine, and dCTP/ddCTP – cytosine
The 3’-OH group (pentose sugar – deoxyribose in DNA) of a nucleotide is necessary for the formation of phosphodiester bonds. However, ddNTPs lack this group meaning extension stops when they are integrated. This results in billions of copies of the specific DNA sequence stopped at random lengths
In automated Sanger sequencing, all 4 of the ddNTPs are mixed together in the same single reaction with each 4 of the dNTPs having a distinctive fluorescent marker.
2. Size Separation by Gel Electrophoresis
In this phase, the shortened nucleotides are distinguished according to size by the use of gel electrophoresis. Gel electrophoresis involves transferring the chain-terminated DNA sample
105 Bates, S. (2019). Base Pair. [online] Genome.gov. Available at: https://www.genome.gov/genetics-glossary/Base-Pair [Accessed: 20 November 2024]
into wells at one end of the gel matrix. Applying an electric current causes the negatively charged DNA to be pulled towards the positive electrode on the other side The smaller the fragment of DNA, the further it will travel in the gel due to minimal friction.
37
3. Gel Analysis & Determination of DNA Sequence
Using a laser, a computer reads the individual fluorescent label of each ddNTP within the gel from smallest to largest This creates a chromatogram of how far each nucleotide travelled, in turn generating and determining the original 5’ to 3’ DNA sequence.106
Applications and Potential Benefits
The Human Genome Project has had countless positive knock-on e ects for numerous industry sectors including:
Molecular Medicine
The use of intricate genome maps has helped biomedical scientists identify genes correlated with many conditions such as Alzheimer’s disease and familial breast cancer. These have allowed for early detection of genetic predispositions to diseases. The benefits have not just been for diagnosing diseases but also treatment New and more e ective drugs can be developed and
106 Sigma Aldrich (n d ) Sanger Sequencing Steps & Method [online] Merck Available at: https://www.sigmaaldrich.com/GB/en/technical-docume nts/protocol/genomics/sequencing/sanger-sequencing?sr sltid=AfmBOortCN197uTKCJIlc8UtikiBnfafrMiK33W3BmDJ n4uzap7IgB9h [Accessed: 9 December 2024]
Figure
potentially in the future gene therapy could be a useful tool in replacing faulty genes
Agriculture and Environmental Applications
Microbial gene sequencing has introduced a new wave of research into biofuels and biotechnologies Environmental monitoring techniques can be cultivated for detecting pollutants and predicting environmental change Understanding not only our own genes but the genes of microorganisms is vital for delving into the makeup of our planet and way in which we can ultimately amend it. Understanding the genetics of animals and plants as well can provide us with the blueprints to generate stronger and more resistant crops and livestock. This will increase food yield and its nutritional value whilst also reducing the cost for farmers
DNA Forensics
DNA is amazingly complex and thus solely unique to each individual. This can prove fundamental in identification The use of gene identification can be used to: Identify potential suspects whose DNA may match evidence left at crime scenes, exonerate persons wrongly accused of crimes, identify crime and catastrophe victims and establish paternity and other familial relationships 107
Ethical, Legal, and Social Issues
Alongside all the advantages of the Human Genome Project and similar research, there are some downsides to consider Issues include:
▪ Availability fairness – which sectors or organisations should be allowed access to genetic information?
▪ Privacy and confidentiality – who owns and controls genetic information?
▪ Psychological impact and stigmatisation –how will society perceive individuals based o their genetic information?
▪ Health and environmental issues – are genetically modified crops safe for consumption?
▪ Philosophical implications - where is the line between medical treatment and enhancement and how will free will be a ected?
▪ Uncertainties – how reliable are genetic tests?
▪ Reproductive issues – could your right to reproduce be controlled based o your genes?
▪ Clinical issues – how will society be prepared to make informed decisions, and will medical professionals have to be trained?108
107 U S Department of Energy Genomic Science program (n.d.). Potential Benefits of HGP Research. [online] Human Genome Project Available at: https://doe-humangenomeproject.ornl.gov/potential-ben efits-of-hgp-research/ [Accessed: 12 December 2024]
108 U S Department of Energy Genomic Science program (n d ) Ethical, Legal, and Social Issues [online] Human Genome Project Available at: https://doe-humangenomeproject ornl gov/ethical-legaland-social-issues/ [Accessed: 12 December 2024]
109 Ovation Data (n.d.). The Human Genome Project. [online] Available at: https://www.ovationdata.com/success-stories/the-human -genome-project/ [Accessed: 12 December 2024]
Figure 47
Figure 5109
Role of Reverse Transcriptase in Viral Diseases
By Conner Jay Evans
Reverse transcriptase is a polymerase RNase combination that greatly increases survivability and reproduction of many types of viral diseases.
Reverse transcriptase is the enzyme coded for by many RNA viruses, such as Human Immunodeficiency Virus (HIV). Viruses are dependent on other cells for survival, so reverse transcriptase for the integration of viral DNA into the host cell;s genome, as it catalyses the formation of DNA double helices from mRNA molecules. Once integrated, the host cell transcribes and translates viral DNA base sequences into viral proteins
This article will cover types of viruses that use reverse transcriptase, the structure of the enzyme, and its function in viral replication.
Which viruses use reverse transcriptase?
Reverse transcriptase has a large role in the replication of Metaviridae, Pseudoviridae, Hepadnaviridae, Caulimoviridae, and Retroviridae (such as HIV)110 Other retroviruses include HTLV (Human T-Lymphotropic Virus) types I and II, which can cause some forms of lymphoma and leukemia111 . Metaviridae are retrotransposons; genes that can move and spread via RNA intermediates being reverse transcribed112 , whilst Pseudoviridae are a reverse transcribing virus
110Menéndez-Arias, L., Sebastián-Martín, A. and Álvarez, M (2017) Viral reverse transcriptases Virus Research, 234, pp.153–176. https://www sciencedirect com/science/article/abs/pii/S0 168170216306827 [Online, Last Accessed 08/07/2024]
111Jonathan E Kaplan (2023) What Is an Example of a Retrovirus? Available at: https://www webmd com/hiv-aids/what-is-an-example-o f-a-retrovirus [Online, Last Accessed 08/07/2024]
112 Encyclopedia of Biological Chemistry (2021) Retrotransposon - an overview | ScienceDirect Topics Available at: https://www sciencedirect com/topics/biochemistry-gene tics-and-molecular-biology/retrotransposon#: :text=Ret rotransposons%20are%20mobile%20genetic%20elements %20that%20spread%20via [Online, Last Accessed 08/07/2024]
family with long terminal repeats (LTRs) Primarily observed in eukaryota, LTRs are DNA double helix strands with a complementary sequence on both strands. Hepadnaviridae are small viruses with a partially double stranded viral genome, in which Hepatitis B belongs to its family113 . Hepatitis B is an infection of the liver that is usually spread through bodily fluids such as blood, vaginal fluid, or semen114 Although there are vaccines against the virus, infection may result in liver cirrhosis (scarring) or even prove fatal if left untreated. Caulimoviridae are plant viruses without an envelope that can reverse transcribe115 .
Reverse transcriptase is present in both types of HIV, converting the HIV molecules’ RNA genome into cDNA (short for complementary DNA or copy DNA) that gets inserted into CD4 Th cell’s DNA after slicing of the genome116 The primary receptors of CD4, along with a cellular coreceptor, bind to the HIV protein envelope. This forces a fusion of host cell membranes with viral cell membranes, initiating infection117 , and allowing HIV to deactivate CD4 Th cells on invasion of the genome This alters the proteome, so the cell is damaged and unprepared to start the cell-mediated immune response. Without the immune response, the virus cannot be killed, so it replicates and deactivates
113Li, H , et al (2019) Hepatitis B Virus Infection: Overview Advances in Experimental Medicine and Biology, 1179, pp 1–16 https://pubmed ncbi nlm nih gov/31741331/ [Online, Last Accessed 08/07/2024]
114NHS (2019) Overview - Hepatitis B Available at: https://www nhs uk/conditions/hepatitis-b/ [Online, Last Accessed 08/07/2024]
115Teycheney, P , et al (2020) ICTV Virus Taxonomy Profile: Caulimoviridae. e Journal of General Virology, pp 1025–1026 https://www.microbiologyresearch.org/content/journal/jg v/10 1099/jgv 0 001497 [Online, Last Accessed 08/07/2024]
116Maga, G. (2013). Reverse Transcriptase - an overview | ScienceDirect Topics Available at: https://www sciencedirect com/topics/neuroscience/reve rse-transcriptase [Online, Last Accessed 15/08/2024]
117Wilen, C B , et al (2012) HIV: Cell Binding and Entry Cold Spring Harbor Perspectives in Medicine, (2012), https://www ncbi nlm nih gov/pmc/articles/PMC3405824/ #: :text=To%20infect%20cells%2C%20the%20HIV%20prot ein%20envelope%20%28Env%29,the%20viral%20and%20h ost%20cell%20membranes%2C%20initiating%20infection [Online, Last Accessed 08/07/2024]
more CD4 Th cells leading to a further decrease in antibody presence
There are 2 types of HIV, HIV-1 and HIV-2 Even though both make the immune system weaker, HIV-2 develops more slowly and has a lower transmission rate than HIV-1, however HIV-2 is resistant to certain HIV-1 treatments, so whilst HIV-1 is more likely to prove fatal, HIV-2 may be more di cult to traet118 The most common type of HIV is HIV-1, with cases recorded from all over the globe; he vast majority (around 95%) of people with HIV have HIV-1 Although most prevalent in West AFrica, HIV-2 is slowly starting to appear in regions such as North America, India and Europe119 . HIV causes an ine ciency of the immune system resulting in a decrease in antibody concentration of the blood, because of the deactivation of CD4 Th cells in the blood Once antibody concentration decreases to or below 200 cells/mm3 (200 CD4 cells per cubic millimetre of blood)120 , the individual has developed Acquired Immune Deficiency Syndrome (AIDS)121 . Some life-threatening and serious diseases that occur in HIV-positive individuals are called "AIDS-defining" illnesses122 , with common examples including salmonella, cervical cancer, and pneumonia123 The presence of an ‘AIDS-defining’ illness allows classification of a patient as having advanced stageHIV or ‘AIDS’.
118 Luna Burgess (2024) HIV-1 vs HIV-2: Di erences and similarities Available at: https://www medicalnewstoday com/articles/323893 [Online, Last Accessed 08/07/2024]
119 Luna Burgess (2024) HIV-1 vs HIV-2: Di erences and similarities Available at: https://www.medicalnewstoday.com/articles/323893 [Online, Last Accessed 08/07/2024]
120Cleveland Clinic. (2022). HIV & AIDS: Causes, Symptoms, Treatment & Prevention Available at: https://my.clevelandclinic.org/health/diseases/4251-hiv-ai ds?ref=fu98hcxri1wvg [Online, Last Accessed 25/07/2024]
121 NHS (2021). Overview - HIV and AIDS. Available at: https://www nhs uk/conditions/hiv-and-aids/ [Online, Last Accessed 08/07/2024]
122US Department of Veterans A airs (1993) AIDS-defining illnesses - HIV Available at: https://www hiv va gov/patient/diagnosis/OI-AIDS-defini ng-illnesses asp [Online, Last Accessed 08/07/2024]
123Cleveland Clinic. (2022). HIV & AIDS: Causes, Symptoms, Treatment & Prevention Available at: https://my.clevelandclinic.org/health/diseases/4251-hiv-ai ds?ref fu98hcxri1wvg [Online, Last Accessed 25/07/2024]
Chemical structure and function of reverse transcriptase
Reverse transcriptase, which is an RNA dependant DNA polymerase, directs the synthesis of a DNA molecule using an RNA template124; it catalyses the formation of phosphodiester bonds between adjacent DNA nucleotides forming one DNA strand. Two DNA strands combine to form the double helix. Reverse transcriptase uses complementary base pairing between RNA and DNA nucleotides, in the RNA-DNA hybrid region, to form the correct DNA sequence (also known as cDNA) coded by the mRNA cDNA is synthetic DNA that has been transcribed from a specific mRNA sequence125
Reverse transcriptase, as well as being a type of DNA polymerase, is a type of nuclease; it cleaves nucleic acids, slicing the nucleotide sequence into separate parts126 . Cleaving by reverse transcriptase allows viral genome to integrate with that of the the CD4 Th cell.
124Eun Ha, C (2023) 21 3 6 Reverse transcriptase Available at: https://www sciencedirect com/topics/biochemistry-gene tics-and-molecular-biology/reverse-transcriptase#: :tex t=Reverse%20transcriptase%20is%20an%20RNA-depende nt%20DNA%20polymerase%20that,a%20very%20useful%2 0tool%20for%20molecular%20biology%20research [Online, Last Accessed 04/07/2024]
125 Shchelochkov, O A (2023) cDNA (copy DNA) | NHGRI Available at: https://www genome gov/genetics-glossary/Copy-DNA [Online, Last Accessed 08/07/2024]
126Encyclopedia Britannica. (2024). Nuclease | biology. Available at: https://www.britannica.com/science/nuclease [Online, Last Accessed 25/07/2024]
The structure of reverse transcriptase can be seen in Figure 1127:
The structure of a nucleoside analogue (NRTI) and nucleotide can be seen in Figure 2129:
Here we can see that reverse transcriptase is made of 2 segments: p66 and p51. Both the polymerase and nuclease groups are on the p66 segment p66 has a C-terminal Ribonuclease H domain and has a polymerase domain128 .
Targeting reverse transcriptase in medicine
Reverse transcriptase can be targeted by nucleoside analogues in HIV therapy These are called reverse transcriptase inhibitors (NRTIs). NRTIs work to treat HIV by deactivating the reverse transcriptase enzyme
Here we can see that the only di erence, between the 2 molecules, is that the nucleoside does not have a phosphate group (PO4 3-), and the nucleotide does130 This means that the phosphate-sugar backbone of the usual DNA helix cannot form so less structural support is provided131 . NRTIs work to deactivate reverse transcriptase either by termination of DNA chains or by competitive inhibition of the polymerase domain of the p66 subunit in the enzyme132 In this case, the nucleotide would be the substrate to the polymerase enzyme, and the nucleoside would be the competitive inhibitor The polymerases’ active site binds to the NRTI (nucleoside analogue), preventing nucleotides from doing so, such that new sequences cannot form and viral replication ceases.
127 Source: Biology LibreTexts (2017) 8 8: Reverse Transcription Available at: https://bio libretexts org/Bookshelves/Biochemistry/Book %3A Biochemistry Free For All (Ahern Rajagopal and Tan)/08%3A Basic Techniques/8 08%3A Reverse Trans cription [Online, Last Accessed 29/08/2024]
128Swati Agrawal and David Marcey (2022) HIV-1 Reverse Transcriptase. Available at: https://earth callutheran edu/Academic Programs/Depar tments/BioDev/omm/jsmolnew/hivrt/hivrt.html [Online, Last Accessed 28/08/2024]
129 Ghosh, A (2022) Di erence Between Nucleotides and Nucleosides | ProtonsTalk. Available at: https://protonstalk com/genetics/di erences-between-nu cleotides-and-nucleosides/#google vignette [Online, Last Accessed 29/08/2024]
130 Ghosh, A. (2022). Di erence Between Nucleotides and Nucleosides | ProtonsTalk Available at: https://protonstalk.com/genetics/di erences-between-nu cleotides-and-nucleosides/#google vignette [Online, Last Accessed 29/08/2024]
131 National Human Genome Institute (2024) Phosphate Backbone Available at: https://www genome gov/genetics-glossary/Phosphate-Ba ckbone [Online, Last Accessed 29/08/2024]
132National Library of Medicine (2020) Nucleoside Analogues Available at: https://pubmed.ncbi.nlm.nih.gov/31644243/ [Online, Last Accessed 29/08/2024]
The Biological Aspect of Domesticating Horses
By Phoebe Holden
The domestication of horses over time
Horses have been domesticated for around 5500 years and in that time, they have arguably built our civilisations, from carrying building materials to being the most widely used animal in warfare Cars and public transport are still a relatively modern invention Previously to them, horseback was the only way to travel long distances; this is a massive attribute to their incredible biological strength
However, in the modern-day, horses have somewhat retired as working horses. Now, more breed for sport and enjoyment purposes such as: cross-country, racing, showjumping, dressage. This leads to the question: is it ethical to keep horses for our pleasure and should they not live wild?
To answer this question, we must look at 3 factors of domesticated horses’ lives:
1.) Health (rate of disease in wild vs domesticated)
2.) Quality of life (dietary and physical requirements)
3 ) Type of work (how do natural movements help or hinder)
These are the 3 main factors that equestrians like me consider when caring for our horses.
133 J Tarr, (12 March 2018) ‘The Ancient Equine and How (and Where) We Think It Grew’, Reactor, [online], available at: https://reactormag.com/the-ancient-equine-and-how-an d-where-we-think-it-grew/ (accessed 21 November 2024)
Health
Many equestrians would argue that we look after our horses 10x better than they could look after themselves in the wild In some respects, that’s true however if you look at the causes of some injuries and disease, these can be caused or made worse by ridden work e.g., kissing spine:
● Kissing Spine: This is a common disease in breeds such as warmbloods and thoroughbreds as kissing spine occurs when two or more bone projections at the top of the vertebrae, usually vertebrae T13 to T18, (T15 being the most common)134 touch or overlap in the spine. These breeds are more likely to have it as there are naturally smaller spaces in-between the vertebrae. However, despite this being a naturally occurring disease, it can be made worse by:
- Loose saddles
- Incorrect training
- Trauma and injury
All of these factors are implicated by horses being ridden by us, therefore worsening this already very painful condition However, kissing spine is not a
134 G. Higgins (15 January 2024) ‘The Truth About Kissing Spines in Horses: Symptoms, Causes, Prevention and Management Tips’, Horses Inside Out, [online], available at: https://www horsesinsideout com/post/the-truth-aboutkissing-spines-in-horses-symptoms-causes-preventionand-management-tips. (accessed 11 December 2024)
Figure 1133
fatal disease and can be treated once the symptoms have been identified by:
–
Rest and anti-inflammatory medication to reduce pain and inflammation
- Physiotherapy and massage to improve muscle tone and flexibility
- Correct saddle fit
- Appropriate training and exercise program to strengthen the core muscles
- Ulcers and Abscesses:
These are common occurring problems in stabled horses due to a lack of care from the owner.
Ulcers: This mainly occurs from a lack of constant hay, as the dried grass is used to soak up excess stomach acid and if this excess acid remains, it starts to cause irritation and abrasions to the stomach lining, allowing ulcers to form There are multiple signs of ulcers in equine animals such as:
● Sensitivity around the lower stomach
● Head lifting and biting when fitting the girth
● Bolting/bucking/rearing when shifting weight on their back
There is one other main cause of ulcers which is stress Due to horses being flight animals, they can easily get highly stressed in unfamiliar or uncomfortable environments As owners, we try to minimise stressful situations however sometimes they are inevitable, causing ulcers
Abscesses: These come from stones or other hard materials being stuck in the hoof which further leads to a bacterial infection causing a pressurised hole to build in the hoof wall. Domesticated horses have a lower rate of abscesses compared to those who are wild as before the horse gets ridden the hooves get checked for stones etc. and they are removed This should be done at least once a day to prevent build up.
Although abscesses are a basic problem and easily avoided, once a horse has them it can be a long process to fix. The minimum time for an abscess to fully heal is around 3 weeks though it can range depending on the horse and how early on it is
found. In rare cases, it can take months for the hoof to return to normal
Quality of life
Many argue that the quality of life for a horse decreases once they are domesticated as they live in a stable, don’t get enough exercise, and their diet changes from their natural food However, this simply not true as their supplements change to adapt to their change in work for example:
- Vitamins and mineral: supplements are given to horses for various reasons like growing animals, pregnant and lactating mares, after antibiotic treatment, during any stressful conditions, to enhance the performance, or to correct nutritional deficiencies Based on the requirement, you must select a vitamin-mineral supplement by the advice from your vet
-Turmeric: Just like humans, turmeric for horses has been proven to have many health benefits such as: a smooth and shiny coat, improved movement, aided metabolic processes in digestion and improved gut health
- Cha : This can be used as a supplement for grass in a high concentration as it is dried grass with extra nutrients as stabled horses aren’t free to roam and graze for the whole day. This allows us to work our horses and maintain their natural diet and nutrients while being ridden.
135 K Gowland (30 May 2022) ‘Hoof Abscesses are Common!’, Southwest Equine Veterinary Group, [online], available at: https://www.southwestequine.com.au/hoof-abscesses-are -common/, (accessed 11 December 2024)
Figure
Physical requirements
To counter the argument of horses ‘don’t have enough free space to run’, as a requirement of BHS (British Horse Society), owners must allow their
owners let their horses out for around 6 hours a day for stress relief and exercise
Type of work:
To further aid the comfortability of our animals we use the natural movements of the breed and/or sex of the horse For example, certain breeds of horses can perform certain school movements better than others based on their natural genetic build and make up A good real-life example of this is the Spanish Riding school in Vienna. This is the most historic riding school in the world with its original purpose being to accommodate emperor Ferdinand’s horses from Spain At this school, they only use Lipizzaner stallions This is because their natural movements of being a stallion aids the movements they do in the school called the capriole. Stallions are more capable of performing a capriole because of their natural performance of this jump in the wild for breeding purposes.
It is seen all the time in this industry that we hand select horses for a specific sub-section of the sport For example:
- Warmbloods and thoroughbreds for racing
- Irish sport horses for eventing and jumping
- Hanoverians for dressage
horses some kind of turn out in a large, open space for at least 5 hours a week at a minimum The only exception is for horses who can’t be turned out for medical reasons due to rehabilitation or injury. Although this is a minimum requirement, most
Conclusion
Overall, I hope to convince you that the biological aspect of domesticating horses is positive and helps us to build a happy industry for our horses We try to optimise the natural intelligence and strength of these animals while maintaining their physical health and dietary needs
Why predatory species have a disproportionate e ect on their habitats: the ecological importance of predators.
By Bethany Jones
In contemporary society, media and rumours play a huge role in how we form opinions, often leading to biases against certain persons or, in this case, species Predatory species are often portrayed as evil and cruel for simply doing their role of hunting prey species For hundreds of years, this bias has led to humans actively hunting and killing them to protect their livestock, the hunting is almost always unproportional to the actual threat posed and driven by fear and hatred Humans have been exceptionally e ective in eliminating various predatory species we viewed as threats; we were in fact the superior predator in all of these cases if looking at the number of losses su ered on both sides
A historic example of persecution:
This is seen with the Tasmanian Tiger that was hunted to extinction as they were seen as a threat to livestock, so people shot, trapped, and poisoned them for government bounties136 Despite the misconception that they were aggressive, they were rather timid and rarely fought against capture from humans. Furthermore, recent evidence demonstrates that they lacked the bite force to prey on sheep, let alone anything larger and they mainly preyed on frogs and small mammals Instead, the British that brought the sheep with them when they colonised Australia also brought feral dogs These dogs are what the latest evidence suggests actually killed the sheep. Humans came and brought the predators and the prey and then
136 Business Insider, ’10 animals that have been hunted to extinction’, Business Insider, 2013, https://www businessinsider com/10-animals-that-havebeen-hunted-to-extinction-2013-, (accessed 29th October 2024)
killed a completely unrelated species out of a lack of understanding.137
The loss of this keystone species led to an awful deterioration of Tasmania’s ecosystem: small rodents and larger herbivores over-gorged on vegetation without a larger carnivore to keep their populations under control, leading to soil erosion138 Soil erosion often causes a decrease in soil fertility which greatly reduces crop yields139 , thus the problem of agricultural ine ciency that caused the extinction of the Tasmanian Tiger was worsened by the loss of them This poignant and ironic story is one of many of its kind It clearly demonstrates how humans’ unfortunate ignorance to the balance present in ecosystems and lack of understanding for how important large predators are can destroy the balance that was there The issues of declining biodiversity persist in Australia to this day, with one third of mammal extinctions since the 18th century occurring there. This is due to invasive species, such as the feral dogs, rabbits, and foxes, as well as indigenous land management
137 R Rawat, ‘Remembering the Tasmanian tiger or thylacine’, Natural History Museum, https://www nhm ac uk/discover/remembering-tasmania n-tiger-thylacine.html#: :text=Research%20suggests%20 that%20the%20jaws,culprits%20of%20the%20livestock%2 0losses., (accessed 29th October)
138 The Environmental Defence Initiative, ‘The revival of the Tasmanian tigers’, Medium, 16th January 2024, https://medium com/@environmentaldefenseinitiative/th e-revival-of-the-tasmanian-tigers-1d82a1dd1d59#: :text =The%20Tasmanian%20tiger%2C%20an%20important,to %20the%20shores%20of%20Tasmania , (accessed 29th October 2024)
139 D Sulaeman and T Westho , ‘The causes and e ects of soil erosion, and how to prevent it’, Worlds resources institute, 7th February 2020, https://www.wri.org/insights/causes-and-e ects-soil-ero sion-and-how-prevent-it#:~:text Soil%20erosion%20dec reases%20soil%20fertility,more%20likely%20to%20happe n%20again , (accessed 29th October 2024)
practices such as wildfire management no longer being used 2
It is too late for us to rectify our actions regarding the Tasmanian Tiger, but there are hundreds of other keystone predators that ecosystems rely on, and we still have time to save them. If we can understand their lives, importance, and the relationships they form then, perhaps, we will be able to peacefully coexist with every other species currently fighting to survive alongside us.
What roles do predators play in ecosystems?
Keystone species are those that have an unproportional e ect on their ecosystem in comparison with their population size. The loss of them leads to a chain of events that can cause the collapse of ecosystems and, if not, the ecosystem will be remarkably di erent after they disappear 140 A considerable proportion of keystone species are predatory species, as it does not take a large population to control all other organisms in that ecosystem, particularly if they are an apex predator 141 There are other types of keystone species, such as beavers, that modify the environment142 thus have a large e ect on other organisms living there, but we will not go into those, it is just important to know that any species can be a keystone species.
Predators keep the balance of ecosystems by controlling the populations of prey species that can
140 NRDC, ‘Keystone species 101’, NRDC, 9th September 2019, https://www.nrdc.org/stories/keystone-species-101#regio n, (accessed 29th October 2024)
141 National Geographic, ‘Role of keystone species in an ecosystem’, National geographic, https://education nationalgeographic org/resource/role-k eystone-species-ecosystem/, (accessed 29th October 2024)
142 Defenders of wildlife, ‘What is a keystone species?’, Defenders of wildlife, 16th February 2023, https://defenders.org/blog/2023/02/what-keystone-specie s#:~:text Chris%20Canipe-,Ecosystem%20Engineers,suc h%20as%20flooding%20or%20drought., (accessed 29th October 2024)
over-graze and drastically change an environment. One such example being sea urchins in kelp forests, when urchins form herds they can eat 30 feet of kelp forest per month143 Similarly, to coral reefs, kelp forests o er a rich and diverse coastal habitat for many aquatic species, as well as reducing shoreline erosion rates since they decrease the size and speed of approaching waves.
8 Thus, their survival is vital to a healthy marine environment, and that is where predatory species come into the utmost importance When the population of species that predate on the sea urchins fall then the size of urchin herds swell massively. Once an area of kelp forest has been decimated by this herd, all the other species that had been living there are scared o and that section of sea floor becomes almost devoid of life.
144
When the urchin population is decreased then the kelp forest can recover, but only if enough of the herd is removed to ensure that the new growth cannot all be eaten There has been success with humans diving and removing up to 6,000 lbs of urchins in barren areas that were once kelp forests allowing the area to recover 145 These astounding numbers of sea urchins would possibly not have occurred if humans had not hunted sea otters to near extinction in the 18th and 19th centuries.146 Sea
143 Shark Allies, ‘Kelp forests, urchins and sea stars: a delicate balance’, Shark allies, https://sharkallies org/oceans-knowledge-base/kelp-fore sts-urchins-and-sea-stars-a-delicate-balance#: :text=I n%20herds%2C%20urchins%20can%20consume,nicknam e%20of%20“zombie%20urchins”., (accessed 29th October 2024)
144 D. Benningfield, ‘Sea urchins’, Science and the sea, 29th November 2008, https://www.scienceandthesea.org/program/200811/sea-u rchins#:~:text=Normally%2C%20sea%20urchins%20are% 20kept,predators%20drops%2C%20the%20urchins%20thr ive , (accessed 29th October 2024)
146 K. Garibaldi., (2018). Sea Otter. [online] Defenders of Wildlife Available at: https://defenders.org/wildlife/sea-otter. (Accessed 29th October 2024)
otters can eat an immense number of sea urchins, with adult males eating up to fifty urchins a day,147meaning it would take approximately 120 adult male sea otters to eat the 6,000 lbs of urchins that humans had to remove to allow the kelp forest to heal. If we had kept a stable and healthy population of sea otters, then we would be able to keep urchin densities low enough to stop overgrazing but ensure they can still carry out their roles of removing microalgae from corals to ensure they can grow 148
Predators face a greater risk when imbalance occurs in an ecosystem; if there are not enough prey, their predators will starve and die In addition, a lack of predators leading to too many prey animals not only results in overgrazing that a ects the food supply of other species which may use the same food source, but can also lead to an increase in diseases being spread.149 Predators often target individuals that are dying or su ering from illness as they are easier to catch, thus resulting in a sort of natural disease prevention It is even suggested that some predators such as wolves have heightened senses allowing them to pick out infected prey before symptoms even arise properly, preventing them from spreading the disease at the height of contagiousness However, it must be noted that some scientists argue that predators cause prey to bunch up, increasing the risk of disease transmission. 150
148 Bernardi, D. (2023). Sea Urchins Are Struggling to ‘Get a Grip’ as Climate Change Alters Ecosystems [online] SU News. Available at: https://news syr edu/blog/2023/08/15/sea-urchins-are-str uggling-to-get-a-grip-as-climate-change-alters-ecosyst ems/ (Accessed 29th October 2024)
149Science World (n d ) Carrying Capacity [online] Available at: https://www scienceworld ca/resource/carrying-capacity/ (Accessed 9th December 2024)
150 Animal Ecology in Focus (2022) Do predators create healthier prey populations? [online] Available at: https://animalecologyinfocus com/2022/01/25/do-predator s-create-healthier-prey-populations/ (Accessed 9 Dec. 2024)
Yet, when weighing the costs against the benefits, it could be argued that predators targeting the sickly in the herd is of greater benefit to the overall population than the possible risk of increased transmission during the hunt caused by bunching of organisms.
Some predators have a greater impact when reducing diseases in habitats compared to others. One such group being vultures, they are scavengers and eat carrion. However this is not what makes them so astounding, for many predators scavenge for the dead It is their intensely acidic stomach acid, and unique genetic code that provide an impressively strong immune system151 that makes them so important in ecosystems. The bearded vulture has a stomach acid pH of less than one and can digest bones. This allows them to return nutrients to the soil at a higher rate as well as eat carcasses infected with deadly diseases such as anthrax that would kill others living in the area 152
A hope for the future?
There is a growing consensus in the scientific community that the reintroduction of large predators that have been hunted to extinction in certain habitats should be reintroduced to restore the ecological balance Currently, the most feasible of these projects in the UK is the reintroduction of the Eurasian lynx to Scotland 153 There is a need for the return of large mammalian predators in the UK to reduce growing prey numbers, for example there is a large issue with deer overpopulation.
151 Mongabay Environmental News (2015) New study uncovers why vultures don’t get sick from eating rotten carcasses [online] Available at: https://news.mongabay.com/2015/10/new-study-uncovers -why-vultures-dont-get-sick-from-eating-rotten-carcas ses/. (Accessed 9th December 2024)
152 Barbara (2023) Earth Day 2023: How vultures contribute to a healthier planet [online] Vulture Conservation Foundation Available at: https://4vultures org/blog/vultures-contribute-to-a-healt hier-planet/ (Accessed 9th December 2024)
153 Rewilding Britain (2024) Wolf reintroduction & conservation. [online] Available at: https://www rewildingbritain org uk/why-rewild/reintrod uctions-key-species/key-species/eurasian-wolf. (Accessed 9th December 2024)
This has a ected bird populations, reduced nesting in areas with deer has significantly impacted robin and wren populations. 154
This is why wolves, bears, and of course the lynx are under consideration for return to the UK; however, there are considerable social and economic implications These include social opinion and financial compensation for loss of livestock, along with training for local farmers and people on how to deal with the new species. At present, there has been no success with getting permission to reinstate larger predators in the British Isles. Alongside the obvious socio-economic issues, there are issues with finding habitats large enough and far enough from urban settlements. 155
Conclusion
The need for predators in a healthy ecosystem has been understated and misunderstood over the years, but we as a society are finally beginning to appreciate the need for these animals. Balance is necessary in nature, and though in the past humans have dominated landscapes rather than living amongst them, the proposal of reintroductions of predators and breeding programmes to stabilise diminishing populations provides hope for a future where the predator prey cycle will be less controlled by humanity. If these relationships can be restored and maintained, biodiversity will flourish and perhaps allow the cohabitation of man and ‘beast’ once more
154 Sky News (n d ) Spiralling deer population ‘devastating’ UK nature - prompting calls to reintroduce wolves and lynx [online] Available at: https://news.sky.com/story/spiralling-deer-population-d evastating-uk-nature-prompting-calls-to-reintroduce-w olves-and-lynx-13093150 (Accessed 9th December 2024)
155 Rewilding Britain (2024) Wolf reintroduction & conservation. [online] Available at: https://www rewildingbritain org uk/why-rewild/reintrod uctions-key-species/key-species/eurasian-wolf (Accessed 9th December 2024)
Migration: A Brief Overview
By Katie Lea
ALL information in the following article has been collected from the sites below:
● RSPB – migration, Bird Migration Facts and Information, available at: https://www.rspb.org.uk/birds-and-wildlife/bir d-migration, (last accessed 20/11/2024)
● World Migratory Bird Day, World Migratory Bird Day Unveils 2025 Conservation eme: Creating Bird-Friendly Cities & Communities, available at https://www.worldmigratorybirdday.org/news/ 2024/world-migratory-bird-day-unveils-2025conservation-theme-creating-bird-friendly-cit ies, (last accessed 20/11/2024)
Migration, in simple terms, is the seasonal movement of animals from one region to another. One of the most commonly thought of examples of this is birds. Around 2,000 bird species migrate each year as well as hundreds of other species on land and in our oceans
Why birds migrate
Migration happens so that di erent species can take advantage of seasonal resources essential to their survival These resources mainly include food and breeding grounds, though there are many other factors that play their part
On migration, many birds often follow a route roughly the same each time, though some birds return by a di erent route to take advantage of changes in winds and the weather. Migration is a behaviour that has evolved over a long period of time, and it works by the use of environmental cues A bird’s body tells it when to migrate Changes in day lengths and temperature causes the release of hormones into a bird’s system which causes them to behave di erently, encouraging them to set o on their journey
Populations
Over time, many species have stopped migrating due to the changes in the world’s temperatures. An example of this is the European robin A well-known symbol of Christmas, robins used to migrate to the UK for Winter Our robins are cold-hardy birds who tend now to only migrate from the much colder countries in Europe further North
In Autumn in the UK, we see a di erence in populations of our birds Our Summer visitors depart as our Winter visitors return. Two examples of migrating bird species include:
Swallows:
Swallows migrate 6,000 miles between the UK and South Africa twice a year They nest in the UK during the Summer months and, as they feed on aerial insects, depart again in Autumn to where their food source is less scarce.
Redwing:
Redwings spend October to April in the UK, and often travel by night They are rather a rarity among birds as they rarely return to the exact same place each Winter. Redwings are the UK’s smallest species of true thrush and, like the swallows, migrate in response to food supply.
Threats
Many of our migrating birds are making their way onto the red list Dangers to migrating birds include:
Bad weather:
We’ve seen an increase in severity of storms recently due to global warming and climate change, including larger, more destructive hurricanes.
Habitat loss:
The loss of places to stop, rest, and eat along the way is causing more and more birds to die of starvation and exhaustion each year. Predators are also a threat as they mean migrating birds cannot rest for too long at each stop. Huge flock numbers, of species such as geese, make them an easy target as a food source.
Experience:
Young birds in particular can often go astray and struggle to find their way back. Usually around 35% of young individuals die on their first migration, leading to survival of the fittest.
Humans:
Tall, man-made objects such as reflective, glass skyscrapers or wind turbines can disorient birds
Both legal and illegal hunting of these birds also decreases their numbers as they are often trapped on route
World Migratory Bird Day
World Migratory Bird Day is dedicated to building awareness around the need to protect migrating bird species and their habitats This is held on the 10th of May 2025, and its key theme for 2025 will be promoting the creation of bird-friendly cities The campaign highlights the importance that every community can play its part in helping humans and migratory birds to co-exist
Cardiovascular Disease and Defects
By Sanya Syed
The heart. Not the biggest organ we have, yet one of the most important Some would even consider it the fundamental bridge between our life and death. But despite it being such a vital organ, unfortunately defects and diseases still present themselves and can be influenced due to several di erent reasons including genetics, unhealthy lifestyle, ethnic background and many others Cardiovascular disease is simply defined as any condition a ecting the heart or blood vessels 156 There is regrettably a long list of the various types of cardiovascular diseases, some of which will be explored in this article
Congestive Heart Failure
Congestive heart failure (CHF) is a long term heart condition157 where the performance of the heart muscle is ine cient and consequently results in a low supply of blood to the rest of the body 158 Usually, this is when either one or both lower two chambers of the heart (right and left ventricle) become weak and cannot pump blood 159 Therefore, blood returns to the heart faster than it can be pumped back out which results in blood getting “congested”.160
156 National Health Service (2022b) Cardiovascular disease [online] NHS Available at: https://www nhs uk/conditions/cardiovascular-disease/ [Accessed 15 Nov 2024]
157 Cleveland Clinic (2023). Congestive Heart Failure. [online] Cleveland Clinic Available at: https://my.clevelandclinic.org/health/diseases/17069-hear t-failure-understanding-heart-failure [Accessed 16 Nov 2024].
158 Malik, A , Brito, D , Vaqar, S and Chhabra, L (2023) Congestive Heart Failure. [online] National Library of Medicine Available at: https://www ncbi nlm nih gov/books/NBK430873/ [Accessed 16 Nov 2024]
159 Mayo Clinic (2023) Edema - Symptoms and causes [online] Mayo Clinic Available at: https://www mayoclinic org/diseases-conditions/edema/s ymptoms-causes/syc-20366493 [Accessed 16 Nov. 2024].
160 Blumenthal, R and Jones, S (2019) Congestive Heart Failure: Prevention, Treatment and Research. [online] John Hopkins medicine Available at:
Common symptoms of this heart disease include shortness of breath while performing activities, or sometimes even while laying down, fatigue and weakness, swelling in the legs ankles and feet and potentially stomach/belly area (since the heart is not pumping enough blood fluid builds up in body which can present as an edema in the legs and feet161), rapid or irregular heartbeat (which can usually be determined using an ECG or EKG162), reduced ability to exercise, coughing which brings up a pink/white mucus sometimes with blood, very rapid weight gain (due to fluid buildup), nausea/lack of appetite, di culty concentrating/decreased alertness and potentially chest pains if the heart failure initiated from a heart attack 163 CHF can present itself in three main forms: right side failure, left side failure and high-output heart failure 164 In right side failure, the heart’s right ventricle is too weak to pump enough blood to the lungs, blood therefore builds up and congests in the veins which also causes fluid to be pushed out into the tissues of the body. The most common symptoms of right-side heart failure would be shortness of breath and swelling
https://www hopkinsmedicine org/health/conditions-and -diseases/congestive-heart-failure-prevention-treatment -and-research [Accessed 16 Nov 2024]
161 Mayo Clinic (2023b) Edema - Symptoms and causes [online] Mayo Clinic. Available at: https://www mayoclinic org/diseases-conditions/edema/s ymptoms-causes/syc-20366493 [Accessed 16 Nov. 2024].
163 Mayo Clinic (2023c) Heart failure [online] Mayo Clinic Available at: https://www mayoclinic org/diseases-conditions/heart-fa ilure/symptoms-causes/syc-20373142 [Accessed 16 Nov 2024]
(of belly area and/or feet/ankles/legs).165 Whereas, left sided heart failure is when myocardial function (heart muscle) is insu cient on the left side resulting in a lack of blood being pumped around the whole body This results in organs not receiving oxygen rich blood which feeds into other complications such as right-sided heart failure or organ damage 166 Finally, the rarest type of congestive heart failure is high output. This is when the heart is pumping blood normally but is unable to keep up with the increasing demand of the body and consequently becomes weak and loses the ability to e ectively pump blood 167
Figure 1168:Image of the comparison between normal heart and a heart a ected by congestive heart failure
Heart failure can be caused by several factors, some being natural/uncontrollable factors and others being lifestyle dependent These factors include: Coronary heart disease, which can lead to heart attack (causing the heart muscle to endure
166 Cleveland Clinic (2021a). Left-sided heart failure: Symptoms, causes and treatment [online] Cleveland Clinic Available at: https://my clevelandclinic org/health/diseases/22181-left-s ided-heart-failure [Accessed 17 Nov 2024]
167 Cleveland Clinic (n d ) High-output heart failure [online] Cleveland Clinic Available at: https://my clevelandclinic org/health/diseases/24660-high -output-heart-failure [Accessed 17 Nov 2024]
168 Guysandstthomasspecialistcare (n.d.). What Is Congestive Heart failure? Available at: https://guysandstthomasspecialistcare.co.uk/news/4-stag es-of-congestive-heart-failure [Accessed 17 Nov 2024]
damage and work less e ciently169); Congenital heart disease, which presents from birth and cardiomyopathy - a disease where the heart muscle either sti ens, enlarges or weakens the heart (this type is usually hereditary) Type 2 diabetes can also present as a risk factor for congestive heart failure since high blood pressure can damage the blood vessels and the nerves controlling the heart and could contribute to coronary heart disease, for which the risk is explained above Although it may seem unrelated, kidney function can a ect the heart. A poor kidney function may lead to a higher chance of having congestive heart failure due to the increasing strain on the heart. One of the most common causes of heart failure is hypertension (high blood pressure) - this causes the heart to sti en which eventually weakens heart muscle.
Arrhythmias are when the heart has an irregular beat, this can cause it to put a strain on the heart's ability to pump blood, consequently tiring the muscles of the heart More lifestyle-based causes may include smoking (chemicals like nicotine can thicken blood and form clots which get stuck in the heart and are also a potential risk factor for coronary heart disease) Taking illegal drugs like cocaine can force the heart to work faster and harder even when it shouldn't. This can lead to conditions like arrhythmia and heart attacks 170
Diagnosing heart failure is extensively di cult, whereas there are many tests which can indicate congestive heart failure One of the initial tests a doctor may perform is an EKG (electrocardiogram). This is like a Holter monitor which supplies the same function but in a di erent way,171 it measures
169 NHS Choices (2019). Complications - Heart attack. [online] NHS Available at: https://www.nhs.uk/conditions/heart-attack/complicatio ns/ [Accessed 17 Nov 2024]
170 Guysandstthomasspecialistcare (2024) What are the 4 stages of congestive heart failure? [online] Guy’s and St Thomas’ Specialist Care Available at: https://guysandstthomasspecialistcare co uk/news/4-stag es-of-congestive-heart-failure/ [Accessed 18 Nov 2024]
171 Blumenthal, R. and Jones, S. (2019b). Congestive Heart Failure: Prevention, Treatment and Research [online] John Hopkins medicine. Available at: https://www hopkinsmedicine org/health/conditions-and
the heart's electrical activity for 24 to 48 hours prior 172 Another test may be a chest X-ray which will show the structure of the chest and heart to determine whether the size of the heart or surrounding area is a ected which can narrow down the type of disease. Ultrasounds of the heart can be done using an echocardiogram or additionally a Doppler ultrasound which will provide an image of the flow of blood to the heart and lungs This may be useful to acknowledge which side of the heart has been a ected. A more practical test is the exercise stress test. The patient is asked to perform an activity which would increase the heart rate normally such as running on a treadmill or riding a stationary bike If they are unable to take this test, an alternative is to administer a drug which would have the same e ect Ultimately, this is to test heart performance under stress (good/bad) and a reasonable evaluation can be made from this about the type of heart disease the patient may be su ering with 173 Finally, another test which can be done is the BNP blood test BNP abbreviates for B-type natriuretic peptides which is a certain hormone in blood. If levels of this hormone are too high this is a large indication of heart problems, especially heart failure.
174
Treatment for congestive heart failure is typically only to control and relieve symptoms since there is unfortunately no cure. Therefore, doctors make their best attempt to slow down the progression of
172 British Heart Foundation (2022). ECG. [online] www bhf org uk Available at: https://www.bhf.org.uk/informationsupport/tests/ecg [Accessed 18 Nov 2024] -diseases/congestive-heart-failure-prevention-treatment -and-research [Accessed 18 Nov 2024]
173 Blumenthal, R. and Jones, S. (2019c). Congestive Heart Failure: Prevention, Treatment and Research [online] John Hopkins medicine Available at: https://www hopkinsmedicine org/health/conditions-and -diseases/congestive-heart-failure-prevention-treatment -and-research [Accessed 18 Nov 2024]
174 Cleveland Clinic (2022) B-Type Natriuretic Peptide (BNP) Test: Normal Levels & Function. [online] Cleveland Clinic Available at: https://my.clevelandclinic.org/health/diagnostics/22629-b -type-natriuretic-peptide [Accessed 18 Nov 2024]
the disease.175 In earlier stages of heart failure, lifestyle changes such as exercise or daily activity of some sort while eating healthier foods and aiming for a healthy body weight (BMI) will hopefully limit the strain on the heart, which will lower the e ects of the symptoms. Other lifestyle changes such as quitting smoking, avoiding /limiting alcohol intake, managing stress and getting good quality sleep all contribute to helping the heart become slightly healthier In terms of medication, doctors may prescribe slightly alternating medication considering whether the heart failure is right or left side Typically for right side heart failure 2 main types of medications are recommended: Medicines that remove extra sodium and fluid from the body, and medicines which relax blood vessels. Diuretics (such as chlorothiazide176) have proved to be very useful to remove fluid from the body which may have been created due to the lack of blood circulation Aldosterone antagonists, such as spironolactone, lower the amount of blood the heart must pump and consequently relieve the strain on the heart For left side heart failure these same 2 types of medication are recommended, sometimes alongside other types This is primarily because the left lower chamber of the heart is the side with thicker muscle and therefore it requires more energy and more support since this is the side where blood leaves to be pumped around the rest of the body Medication which lowers heart rate, for example beta blockers, ivabradine etc. to make it easier for the heart to pump blood 177 Alternative to medication and lifestyle changes, surgery may
175 NHS (2022). Treatment - Heart Failure. [online] NHS. Available at: https://www.nhs.uk/conditions/heart-failure/treatment/ [Accessed 18 Nov 2024]
176 Mountsinai (n.d.). Heart failure - fluids and diuretics
Information | Mount Sinai - New York [online] Mount Sinai Health System Available at: https://www mountsinai org/health-library/selfcare-instr uctions/heart-failure-fluids-and-diuretics [Accessed 19 Nov 2024]
177 National Heart, Lung, and Blood Institute (2022) Heart Failure - Treatment | NHLBI, NIH. [online] www nhlbi nih gov Available at: https://www.nhlbi.nih.gov/health/heart-failure/treatment [Accessed 21 Nov 2024]
be the only option for some individuals to survive. Heart transplant surgeries are commonly seen with these types of heart diseases however, the lack of heart donors occasionally makes this more di cult due to the long wait Due to extremely poor health, some patients may not have enough time to wait for a new heart.178 Catheter ablation is a non-invasive surgery to treat arrhythmia, which could be causing congestive heart failure. Simply, in this procedure a thin tube (catheter) is inserted into the blood vessels to control areas of tissue which are causing the imbalances in electrical impulses One more treatment is an LVAD (left ventricular assist device) which is positioned on the left ventricle and has external controls which helps the heart to pump blood around the body Except for these there are many other surgical/small procedural treatments which a patient can receive specific to them and the cause of their disease 179
Survival rates for congestive heart failure can range from:
80%-90% for one year
50%-60% for five years
30% for 10 years.
These are only statistics, and everybody is di erent so life expectancy can only be estimated but not determined when it comes to this kind of fatal disease 180
Cardiac Tamponade
The heart has a small space between the heart muscle and the outer sac which covers the heart known as the pericardium of the heart. Cardiac tamponade is when blood or fluid builds up in the pericardium, causing it to create pressure on the heart which consequently limits the heart's ability to e ciently function 181
Su erers often complain of symptoms including breathing problems which can range from rapid breathing to severe chest pain which gets worse with every breath and can come with a flow of coughing Sharp chest pain may also be experienced which can a ect the neck, shoulders, back or abdomen A discomforting feeling is experienced by some, which may be relieved by sitting upright or leaning slightly forward. Some people get symptoms of shock, for example turning pale grey/blue, having palpitations, experiencing anxiety and restlessness, sometimes leading to dizziness, fainting, lightheadedness, weak pulse etc. (this is usually due to low blood pressure which may cause symptoms of shock183) Some patients may even experience symptoms like jaundice
178 Yale Medicine. (n.d.). Heart Failure Surgery. [online] Available at: https://www.yalemedicine.org/conditions/heart-failure-s urgery [Accessed 21 Nov 2024]
179 Cleveland Clinic (2019b) Heart Failure Surgery | Cleveland Clinic [online] Cleveland Clinic Available at: https://my clevelandclinic org/health/treatments/12905-h eart-failure-surgery [Accessed 21 Nov 2024]
181 Medlineplus gov (2019) Cardiac tamponade: MedlinePlus Medical Encyclopedia. [online] Available at: https://medlineplus gov/ency/article/000194 htm [Accessed 22 Nov 2024]
182 Wikipedia (n d ) Cardiac Tamponade Wikipedia Available at: https://images app goo gl/DfciFTMdsqF52H2w9 [Accessed 22 Nov 2024]
183 Cedars-Sinai. (n.d.). Articles. [online] Available at: https://www cedars-sinai org/health-library/diseases-an d-conditions/c/cardiac-tamponade.html [Accessed 22 Nov 2024]
Figure 2182:Image of the heart su ering from cardiac tamponade (pericardial tissue is filling with fluid)
(yellow discoloration of skin/eyes) or swelling and pain in the legs and abdomen
Since the fluid around the heart cannot allow the lower chambers (ventricles) to pump blood fully, oxygen rich blood and nutrients are unable to be transported around the body The most common causes of cardiac tamponade are thoracic dissecting aortic aneurysm (Which is when the walls of the aorta tear and leak blood into the layers of the walls of the artery184) Wounds or viral/bacterial infections in the heart post-surgery or penetrating trauma may cause the pericardial sac to fill, resulting in cardiac tamponade End stage lung cancer can also be a large contributing factor 185 Sometimes the radiation from chemotherapy can negatively a ect the muscle of the heart, especially the pericardial sac. Otherwise, the cancer may unfortunately travel to the heart which may also result in the patient contracting cardiac tamponade. 186 Except from these main factors, there are obviously other variables which directly or indirectly a ect the chances of a patient su ering from cardiac tamponade, however regrettably not all of these will not be covered in this article.
Doctors would usually obviously listen to the heart and check blood pressure/pulse to observe for any irregularities or defects. After this initial exam, sometimes the patient will be tested for a sign of pulsus paradoxus which is when the blood pressure drops significantly when the patient takes a breath. “Beck’s triad” is also a method used by many doctors to identify cardiac tamponade. This
184British Heart Foundation (2022) Aortic aneurysm, dissection and rupture. [online] Bhf.org.uk. Available at: https://www bhf org uk/informationsupport/conditions/a ortic-aneurysm-dissection-and-rupture [Accessed 22 Nov 2024]
185Pennmedicine org (2022) What is Cardiac Tamponade? [online] Available at: https://www pennmedicine org/for-patients-and-visitors /patient-information/conditions-treated-a-to-z/cardiactamponade [Accessed 22 Nov 2024]
186 Healthline. (2017). How Does Lung Cancer A ect the Body? [online] Available at: https://www.healthline.com/health/lung-cancer/e ects-o n-body#heart [Accessed 22 Nov 2024]
includes 3 main symptoms of: low blood pressure, bulging neck veins and heartbeats which sound distant or mu ed when heard through a stethoscope. Despite this being an e cient way to diagnose cardiac tamponade, unfortunately only 10%-40% of cardiac tamponade patients experience Beck’s triad. Other than this, the patient tends to be put through many other medical exams including chest X-ray, CT scan, EKG and sometimes even heart catheterization (thin flexible tube is inserted into blood vessel in either groin, neck or arm which is then threaded through the heart to measure blood pressure and oxygen in heart and lungs).187
Almost immediately after diagnosis of cardiac tamponade a patient will be rushed to be provided emergency treatment. Typical treatment is pericardiocentesis, in which a long thin needle is inserted into the skin at a 30–45 degree angle and the liquid from the pericardium is drained out. This procedure is not thought to be too risky considering there is only a mortality rate of approximately 5% and a complication rate of 15% on average 188 Pericardiocentesis is the preferred method of treatment for this disease, however sometimes surgery may be a safer and more practical procedure. This tends to be when a patient has a preexisting injury which caused the cardiac tamponade, the fluid cannot be removed via a needle or the pericardium needs to be removed either completely or partially (this is usually to help diagnose the cause of the disease and also sometimes prevents the fluid form building up again189) Rarely, a patient may have to
188 Clinical Director, Medicine, Frailty and Networked Service ICSU (2015) Cardiac Tamponade: Emergency Management Subject: Emergency management of cardiac tamponade Policy Number N/A Ratified By: Clinical Guidelines Committee [online] Available at: https://www.whittington.nhs.uk/document.ashx?id=6191 [Accessed 3 Dec 2024]
189 Cedars-Sinai. (n.d.). Articles. [online] Available at: https://www cedars-sinai org/health-library/diseases-an
undergo a thoracotomy. This tends to be when the heart stops beating due to cardiac tamponade, so the doctor will investigate the thoracic cavity to diagnose the problem. To actually test the cause, dependent on the specific patient, medications will be prescribed, including antibiotics or painkillers.190
In the UK around 45,000 patients recieve heart surgery for a variety of reasons, however post-surgery, cardiac tamponade is likely to occur and will be di cult to diagnose as it could be assumed to be other heart conditions. 3 in 10 deaths after cardiac surgery are a result of cardiac tamponade. After acknowledging and researching into this, Dr Fallouh invented a device, named the PerDeCT (Pericardial Device to monitor Cardiac output and diagnose Treatment). This is now the only device which can diagnose cardiac tamponade and provide cardiac monitoring at no extra cost!191
Dextrocardia
Dextrocardia is more of a birth defect instead of a disease. It involves the positioning of the heart to be more on the right side instead of where it typically would be on the left Dextrocardia on its own does not tend to cause many problems, however it can cause other conditions to arise or even a ect the severity of certain conditions leading to severe e ects on the heart, lungs and
Figure 3193 : Image of a normal heart compared to a heart a ected by isolated dextrocardia, in a baby
Dextrocardia can be present in many ways and has many types Isolated dextrocardia is when only the direction of the heart is on the opposite side (right side) - this is the only defect and there are no other abnormalities with the heart or any surrounding organs. Although this type of dextrocardia comes with the least problems, it unfortunately tends to be one of the rarest Dextrocardia situs inversus is when along with the heart, some other organs seem to be on opposite sides of the body For example, the liver might be on the left side instead of, like normally, on the right Quite similar to this is dextrocardia situs inversus totalis This is when all organs present in the chest and abdomen are on the opposite side to where they normally are Patients with this condition may have all their organs functioning perfectly fine or some might have problems with breathing or digestion etc One of the most server types of dextrocardia is heterotaxy syndrome In this type, the patient usually has organs completely misplaced around the body and if left untreated can lead to death. Sometimes, certain organs could be found only partially developed or even not present. Therefore, this condition obviously causes many health problems for the patient which tend to a ect their
d-conditions/c/cardiac-tamponade.html [Accessed 3 Dec. 2024] other vital organs.192
https://my clevelandclinic org/health/diseases/21906-card iac-tamponade [Accessed 3 Dec 2024]
191 University of Birmingham (n d ) New device from Birmingham, U K , to provide early diagnosis for cardiac tamponade. [online] Available at: https://www birmingham ac uk/news/2022/new-device-fr om-birmingham-u.k.-to-provide-early-diagnosis-for-ca rdiac-tamponade [Accessed 3 Dec 2024]
192Doshi, A N (2022) Dextrocardia [online] www hopkinsmedicine org Available at:https://www hopkinsmedicine org/health/conditions-a nd-diseases/dextrocardia [Accessed 3 Dec 2024]
193 Medlineplus (n d ) Normal Heart Vs Heart A ected By Dextrocardia https://medlineplus.gov/ency/article/007326.htm. Available at: https://medlineplus.gov/ency/images/ency/fullsize/22698.j pg [Accessed 6 Dec 2024]
day-to-day life. Dextrocardia also comes with a genetic disorder called Kartagener syndrome which causes problems with the cilia (tiny hairs) on the lungs which typically clean out air and have alternating functions on di erent parts of the body These “problems” are usually respiratory but along with these issues, about 50% of cases of this defect also present with situs inversus totalis And finally, dextrocardia can accompany other conditions like, double outlet right ventricle (the opening of the aorta connects onto the left side of the heart instead of the left.) and endocardial cushion defect (the walls of the four heart chambers are formed incorrectly or their formation is incomplete).194 This is not every type of dextrocardia as there is a long list and still unfortunately new and rare forms of this congenital defect existing.
The cause of this defect looks into genetics and hereditary science since it is congenital. More than 60 genes play a role in where the organs of the body are positioned and the cause of dextrocardia usually takes place when a change in these genes happens, typically quite early in pregnancy It has not yet been determined which specific gene a ects the positioning of vital organs and which gene is responsible for this defect, however researchers are looking into this and narrowing down all the external potential causes for dextrocardia Individuals (parents) tend to be carriers of the defected gene and may be unaware of it as it can be a recessive genetic mutation and present with no symptoms to either parent, but might code as a dominant gene in the child which can result in dextrocardia
While the mother is pregnant, a prenatal ultrasound can be performed to check for and potentially diagnose the child with dextrocardia It is hard to tell with isolated dextrocardia (only the heart has changed to opposite side), therefore if the child has this type it tends to be diagnosed years later But, for those presenting with other genetic
194 Doshi, A.N. (2022b). Dextrocardia. [online] www hopkinsmedicine org Available at: https://www.hopkinsmedicine.org/health/conditions-and -diseases/dextrocardia [Accessed 6 Dec 2024]
defects and syndromes, it becomes easier to diagnose at an earlier stage Later in life, if dextrocardia has not been diagnosed, a physical exam could be done to test for it. Using a stethoscope, if the doctor finds that the heart beat is significantly louder in the right compared to the left they might send the child for some further tests including: chest x-ray, CT scan, echocardiogram, electrocardiogram, heart MRI and sometimes the patient might even be recommended to do genetic test to rule out any other genetic conditions that may be present. Specifically looking into the ECG test (electrocardiogram) - this test shows a picture of the heart’s electrical activity in the form of a heartbeat graph Normally, three types of waves are present here: P-waves, QRS complex and T-waves. In the version of a normal left side heart, these waves would appear upwards, whereas in patients with dextrocardia the ECG readings are flipped and can show as going downwards instead of up Sometimes this can be mistaken for misplaced electrodes which is why this test is usually performed 2 or 3 times to ensure accuracy.195
Most individuals who have congenital dextrocardia may be unaware that they have it since sometimes it can cause them no harm, so symptoms are not visible Usually, this defect is detected better in those who have other conditions along with dextrocardia or have more complex type of dextrocardia which can cause them to feel a range if symptoms including: a sense of continuous and unexplained exhaustion, finding it di cult to gain weight, constantly recurring infection (sinus and lungs), struggling to breathe, having either jaundiced and yellow discolouration of the skin or a pale blue-tinted look, more vivid around the fingers and toes These specific symptoms do not show in all dextrocardia patients and might not be visible at all in some, however if they are found to be present they must be addressed immediately
195 Cleveland Clinic. (n.d.). Dextrocardia: Causes, Symptoms and Treatment [online] Available at: https://my.clevelandclinic.org/health/diseases/23125-dextr ocardia [Accessed 7 Dec 2024]
Dextrocardia usually goes untreated due to the high numbers of individuals who remain unaware that they have this condition Whereas, with those who present with symptoms and cultivate another condition with this defect tend to require surgery or alternative medicated treatment. For those with Kartagener syndrome (problems with cilia), the better treatment options would be to prescribe mucous clearing medication or antibiotics for bacterial infections etc For those patients requiring surgery, before the procedure, they may be given medication which lowers the blood pressure by increasing the force of the heartbeat 196 Some of these medications could include ACE inhibitors (lower blood pressure), inotropic agents (strengthen heart pumping action) or diuretics ("water pills“ which remove excess water from the body) This is only a sample of a few medications which could be given to a dextrocardiac child before surgery to reduce the risk of complications during the procedure The specific surgery for each patient is dependent on the type of dextrocardia they have, the symptoms they present with and also how severe their condition is.197 Despite this, patients with dextrocardia can also prove to have many complications This tends to happen when vital organs are not fully developed or functioning (dextrocardia with heterotaxy syndrome) Conditions like that can lead to dangerous complications such as congestive heart failure, intestinal blockages, lung disorders like respiratory failure or di culty, repeated and critical infections and even infertility problems with males (usually seen in patients with Kartagener syndrome) Dextrocardia is a rare disease that occurs in about 1 out of 12,000 pregnancies despite the abundance of types and mainly allows the patient to have a normal life expectancy unless there are more
severe conditions linked to the dextrocardia itself which may alter the general health of the patient 198
Atrial Septal Defect
Atrial septal defect (ASD) is a congenital defect in which the infant is born with a hole in their heart, typically found in the upper heart chambers Not all atrial septal defects are life threatening though. Very small holes in the heart could potentially not cause any harm and might be diagnosed by chance, while others may close during early childhood or even infancy However, a large and long-term atrial septal defect can massively a ect the functioning of the heart and lungs - consequently leading to severe health problems.199
Figure 4:200Image of a normal heart and a heart a ect by atrial septal defect
Specifically, the hole is usually between the atrial septum (hence the name) which is the wall between the hearts upper two atria This hole in the heart gives the blood an extra route to pass through
(professionally known as a “shunt”). This tends to be a problem because of the mixing of oxygen rich and oxygen poor blood. Oxygenated blood tends to
198 Doshi, A.N. (2022c). Dextrocardia. [online] www hopkinsmedicine org Available at: https://www.hopkinsmedicine.org/health/conditions-and -diseases/dextrocardia [Accessed 9 Dec 2024]
196 Huizen, J (2017) What to know about dextrocardia [online] Medicalnewstoday com Available at: https://www medicalnewstoday com/articles/318875#treat ment-and-outlook [Accessed 9 Dec 2024]
197 Cleveland Clinic. (n.d.). Dextrocardia: Causes, Symptoms and Treatment [online] Available at: https://my.clevelandclinic.org/health/diseases/23125-dextr ocardia [Accessed 9 Dec 2024]
199 Mayo clinic (2022) Atrial septal defect (ASD) - Symptoms and causes [online] Mayo Clinic Available at: https://www mayoclinic org/diseases-conditions/atrial-se ptal-defect/symptoms-causes/syc-20369715 [Accessed 10 Dec 2024]
200 Drugs.com (n.d.). Atrial Septal Defect - What You Need To Know Drugs com Available at: https://www.drugs.com/cg/atrial-septal-defect.html [Accessed 10 Dec 2024]
flow from the lungs into the left atrium then left ventricle to be pumped out to the rest of the body However, in patients with atrial septal defects, instead of the oxygenated blood passing from the ventricle out to the body, it flows into the right atrium/ventricle. The right side contains the deoxygenated blood which gets pumped to the lungs, but when this previously oxygenated blood joins with the oxygen poor blood and is pumped to the lungs – there seems to be an excess of blood in the lungs. 201
Figure 5:202 Image of a heart with atrial septal defect, showing the irregular flow of blood between chambers due to the defect
ASD comes in many di erent types; however, the main four types are: Secundum, primum, sinus venosus and coronary sinus Secundum is the most common type and is when the hole is present
201 Clevelandclinic (n d ) Atrial Septal Defect Clevelandclinic Available at: https://my clevelandclinic org/health/diseases/11622-atrial -septal-defect-asd [Accessed 10 Dec 2024]
202 Cleveland Clinic (2022) Atrial Septal Defect (ASD): Symptoms, Causes, Tests and Treatments. [online] Cleveland Clinic Available at: https://my.clevelandclinic.org/health/diseases/11622-atrial -septal-defect-asd [Accessed 10 Dec 2024]
within the center of the wall separating the right and left atrium, along the atrial septum Primum is the hole in the lower part of the atrial septum, quite close to the tricuspid valve (inflow valve for the right ventricle and therefore closes when blood is pumped out the lungs – to prevent backflow –and opens to allow blood into the chamber of the heart) Sinus venosus is a rarer defect which is when the hole tends to be positioned at the higher areas of the atrial septum and is normally associated with other heart conditions. Finally, another rare type of ASD is coronary sinus. With this defect the patient would find the division of the coronary sinus and left atrium to be missing. The coronary sinus is a large coronary vein which acts as part of the drainage system of the heart and obviously due to this defect severe health problems can arise Serious complications of this defect can include a condition called pulmonary hypertension which simply means a high blood pressure in the arteries of the lungs 203
Congenital defects like ASD tends to be found at birth and with small holes, are not usually diagnosed due to the massively insignificant e ect on the infant (also, small holes tend to close in childhood) However, in some cases individuals are unaware that they or their child has an atrial septal defect until they experience severe symptoms Some of these include recurring lung/respiratory infections (usually due to pulmonary hypertension), feeling breathless while active, fatigued (usually during infant feeding), feelings of skipped heart beats or palpitations, visible swelling of the legs and feet (build-up of fluid due to lack of blood) and in the worst cases, stroke. There is no definitive cause for arterial septal defect, whereas there are risk factors which potentially increase the risk of a child being born with this defect Generally, these are associated with the mother during pregnancy and include factors like the mothers’ diet, emotional and physical environment and any underlying health conditions or
203 sct suk. (2021). Atrial Septal Defect (ASD). [online] Available at: https://scts.org/patients/congenital/procedures/27/atrial septal defect asd/ [Accessed 10 Dec 2024]
medication she took during pregnancy. Aside from this, professionals also believe that changes in genetics could also be a cause for this problem, or maybe that a combination of genes/chromosomes and external environmental factors can provoke the risk of this defect.
ASD can sometimes be diagnosed even when the mother is pregnant, during the prenatal examinations. Although, during pregnancy, an ASD can only be suspected and will be confirmed by a doctor once the baby is born if there is any defect In some cases, people have reached adulthood without acknowledging that they have ASD, and this could be for a variety of reasons. Generally, to test for this condition, a murmur or abnormal sound is detected when listening to the heart through a stethoscope. This would obviously require more testing and a common procedure which is used is the echocardiogram which gives an ultrasound image of the heart, allowing the practitioner to carefully analyze the atrial septum wall to check for problems.204
Again, a small ASD will normally not be too much of a problem and tends to heal during childhood –sometimes the patient may be asked to come in for regular checkups to ensure that the defect is not causing other health problems. However, for those who have a more serious case of ASD, they may be recommended cardiac catheterization or heart surgery. With cardia catheterization, a long thin tube (catheter) is inserted into the hole of the arterial septum through a vessel in the leg which reaches directly into the heart. This closes up the hole and applies pressure to both sides of the wall, as long as this is on the heart it supports this muscle and stops the mixing of oxygenated rich/poor blood Eventually the tissue of the heart rebuilds itself and covers the catheter. After this procedure, the patient would need to take a low dose of aspirin over a period of 6 months and as this may seem like a disadvantage, this option
204 CDC (2024). About Atrial Septal Defect (ASD). [online] Congenital Heart Defects (CHDs) Available at: https://www.cdc.gov/heart-defects/about/atrial-septal-de fect html [Accessed 10 Dec 2024]
requires significantly less healing time and has a lower risk of infection etc compared to heart surgery as this is non- invasive and non-surgical With heart surgery, the child will be placed under anesthesia and the chest will be opened Usually, a man-made surgical material is sewed onto the hole and over time the heart muscle builds upon this. Otherwise, the surgeons may choose that sewing the hole together is the better option. This depends mainly on the situation and condition of the patient. Procedures like this require more healing time and will need the patient to take medication such as acetaminophen or ibuprofen to relieve pain.205
Atrial septal defects are more of a common defect than thought so Approximately 1-2 babies out of 1,00 live births contain children with arterial septal defects 1 in 1,859 babies in the U S are a ected by this defect. Altogether this adds to a shocking number of 2,118 babies unfortunately born with this condition 206
Hopefully, you found this article useful and have been made aware, in depth, of a few di erent cardiovascular diseases/defects This topic is important, not only to recognize the di culties su ered by many but also to have a deeper understanding of those problems, primarily with the aim of discovering a potential cure or more e ective technique to manage these issues than the ones we have today. The heart is a fundamental organ to our bodies and subsequently should be given importance and be taken care of reasonably –even for those who thankfully do not su er from any cardiovascular disease- this article proves to be of use to them, so they are able to accept and acknowledge which dangerous risk factors that they should avoid Thank you for reading
205 Kidshealth org (2016) Atrial Septal Defect (ASD) (for Parents) - Nemours KidsHealth [online] Available at: https://kidshealth org/en/parents/asd html [Accessed 10 Dec 2024]
206 Cleveland Clinic (2022b) Atrial Septal Defect (ASD): Symptoms, Causes, Tests and Treatments. [online] Cleveland Clinic Available at: https://my.clevelandclinic.org/health/diseases/11622-atrial -septal-defect-asd [Accessed 10 Dec 2024]
