Table of Contents
JUDGING AND ORGANIZING COMMITTEE
SESSION 1: LIGHTNING ORAL PRESENTATION
D. Sesath Hewapathirane
SESSION 2: POSTER DISCUSSION
Jessica Harris McCallum
Joanna Slusar SESSION 3: POSTER DISCUSSION
Monica Faria Crowder
SESSION 4: LIGHTNING ORAL PRESENTATION
Jay Ching-Chieh Wang
PARTICIPANT CONTACT INFORMATION
to the 5th Canadian National Medical Student Research
Symposium! The opportunity to indulge your curiosity, make a discovery and thereby make a change in the world is an incredible privilege that few have. Researchers are one group that is very fortunate to do so. At the same time, there is no doubt that learning how to conduct and interpret research, how to develop it into a substantial portion of your career, and how to maintain a successful program is hard work that is fraught with uncertainly, insecurity and the occasional burst of excitement. Over the next several days you have the opportunity to share your experiences, your emerging research projects and your own experimental findings with others. This is an excellent way of helping you determine if research truly is a passion for you. For those individuals who can combine the superb breadth of biological understanding that a medical degree provides with the ability to ask well focused, targeted questions that develops in a graduate degree program, there are a great many professional opportunities. Future options range from leading large multicentre research groups, to running your own laboratory, to being a key collaborator with a sophisticated understanding of the benefits (and limitations) of biomedical research. The trainees this year represent medical schools, and research disciplines, from across Canada. About one third of our 65 attendees are in their first year of hands-on research, one third have intermediate experience and another third are engaged in joint MD PhD programs. As the abstracts demonstrate, your work ranges from studies of individual gene polymorphisms or molecules through to population and health systems research. Because so much ground breaking research is highly multidisciplinary, we have designed the program to increase academic and social interactions between trainees such as yourselves with those enrolled in non-clinical graduate training programs. Make the most of the opportunity! I want to personally thank the individuals and organizations that have enabled us to offer you this special opportunity. Money is never is excess supply and they have gone to great effort to support this initiative. Contributors are listed at the back of the Symposium program. We welcome you and hope you enjoy the novel science, the professional development activities and the pleasures of meeting others with similar interests during your three days here.
Kent T. HayGlass PhD Canada Research Chair in Immune Regulation Director, Advanced Degrees in Medicine University of Manitoba
Judging and Organizing Committees
Poster Judging Teams Team A
Alexandra Kuzyk University of Manitoba
Nathan Bracey University of Calgary
Adam Dmytriw Dalhousie University
D. Sesath Hewapathirane University of British Columbia
Edward Liu McMaster University
Alfred Basilious University of Toronto
JUDGES: ORAL PRESENTATIONS Dr. Christine Zhang, University of Manitoba Samantha Pauls, University of Manitoba
Invited Chairs: Oral Presentations David Lesniak, University of Alberta Stephen Lee, University of Saskatchewan Jennifer LeMessurier, Memorial University of Newfoundland Joanna Slusar, Dalhousie University
ORGANIZING COMMITTEE Dr. Kent HayGlass – Director, Advanced Degrees in Medicine, CNMSRS Coordinator Kimberley Ormiston – Undergraduate and Graduate Research Programs Coordinator Dmitri Krassioukov – Committee Member and MD/PhD student Alexandra Kuzyk – Committee Member and MD/PhD student Cameron Kaye – Committee Member and MD/PhD student
Canadian National Medical Student Research Symposium University of Manitoba Scientific Program Canadian National Medical Student Research Symposium DAY 1: Tuesday, June 4th, 2013 1200 - 2300 Students check-in at the Canad Inns HSC throughout the day. 1400 - 1730 Trainees should mount their posters at this time and prior to 17:30. Posters to be mounted in the allotted 4x4 ft. space. Poster boards are located on the Mezzanine of Brodie Centre. 1600 – 1730 Registration desk opens in Brodie Centre. Note that there are two registration desks for two events. Please ensure you register at the CNMSRS desk which is located beside the CSHRF registration desk. 1750 One bus to St. Charles Country Club (Dress code -business casual). Bus pickup in front of Brodie Centre. Bus leaves at 1750 sharp. 1830 Opening Reception – Mixer 1850 Welcome by Dr. Kent HayGlass , Advanced Degrees in Medicine, CNMSRS Coordinator 1900 Dinner 2015 Clinical Investigator Trainee Association of Canada (CITAC) information overview. Ms. Alexandra Kuzyk, CITAC Executive Committee 2025 ‘Burgeoning Career Opportunities for Clinician Scientists’ Keynote Speaker Dr. Brian Postl, Dean of Medicine, University of Manitoba 2130 Bus returns to Canad Inns HSC
DAY 2: Wednesday, June 5th, 2013 **Students will have 30 minutes to change into casual evening wear/foot wear before leaving from the Brodie Centre entrance for the evening social event. 0745 – 0945 Registration Desk 2nd floor Atrium Apotex Centre – Pharmacy Building (for late arrivals) 0745 – 0825 Continental Breakfast Apotex Centre 2nd floor Atrium 0825 Welcome by Dr. Kent HayGlass – Director Advanced Degrees in Medicine, CNMSRS Coordinator. Procurity Lecture Theatre, main floor Apotex Centre
0830 – 1000 Session I – Lightning Oral Presentations (6 minute presentation, 4 minutes for questions, 10 minutes total presentation time): 8 presentations in this session. Procurity Lecture Theatre – Main Floor – Apotex Centre Chairs; David Lesniak and Stephen Lee Judges: Dr. Christine Zhang and Samantha Pauls Student
University of Toronto
Intrauterine growth restriction (IUGR) and stem cell integration: a novel cerebral palsy rodent model
University of Calgary
Inflammasome-Independent Nlrp3 Regulates Cardiac Myofibroblast Differentiation and Fibrosis
The Impact of Experience on the Implicit Visuomotor Response
Cholesterol Efflux Capacity is Inversely Associated with Severity of Carotid
Hewapathirane, D. Sesath
University of British Columbia
Early-life seizures persistently alter visual brain circuit development via neural activity-dependent synaptotropic mechanisms
The Neuroprotective Compound P7C3 Enhances Functional Recovery Following Neonatal Nerve Injury in a DoseDependent Manner
The developmentally conserved Bmi1-FoxG1-p21 axis regulates tumor heterogeneity and self-renewal in medulloblastoma brain tumour-initiating cells
University of Toronto Slit2/Robo-1 signaling in monocyte recruitment and adhesion
Oral Presenters Poster Display Positions – No CNMSRS Poster Judging Poster #
Intrauterine growth restriction (IUGR) and stem University of cell integration: a novel cerebral palsy rodent Toronto model
University of Calgary
Time (estimat N/A
Inflammasome-Independent Nlrp3 Regulates Cardiac Myofibroblast Differentiation and Fibrosis
The Impact of Experience on the Implicit Visuomotor
Cholesterol Efflux Capacity is Inversely Associated with Severity of Carotid
University Hewapathirane, of British D. Sesath Columbia
Early-life seizures persistently alter visual brain circuit development via neural activitydependent synaptotropic mechanisms
The Neuroprotective Compound P7C3 Enhances Functional Recovery Following Neonatal Nerve Injury in a Dose-Dependent Manner
The developmentally conserved Bmi1-FoxG1-p21 axis regulates tumor heterogeneity and selfrenewal in medulloblastoma brain tumourinitiating cells
University of Toronto
Slit2/Robo-1 signaling in monocyte recruitment and adhesion
University of British Columbia
Clonal tracking studies reveal heterogeneity in mammary stem cell potential â€“ implications for breast cancer treatment
Development of a Targeted Microbubble Contrast Agent for the Molecular Imaging of Endothelial Progenitor Cell Engraftment
University of Toronto
Targeting fatty acid metabolism: a novel chemosensitizing approach for castrationresistant prostate cancer
University of Epidemiology of spinal infections: a chart review Saskatchewan of osteomyelitis, discitis, & epidural abscesses
Wang, Yifan 512
Wang, Jay Ching-Chieh
University of British Columbia
Bridging the gap between open and minimally invasive pancreaticoduodenectomy: the hybrid approach
Effects of AMD-associated factors: CFH Y402H polymorephism, age and drusen, on ocular vitreoretinal environment
University of Manitoba
University of Manitoba
Novel Biomarkers in Pediatric Neuroblastoma
A longitudinal study on the value of the methacholine challenge test as a diagnostic aid for asthma in high-risk adolescents
1000 â€“ 1130 Session 2 Poster Discussion â€“ Brodie Centre, Mezzanine (Coffee available) Poster presentation 3 minutes, discussion 3 minutes (6 minutes total).
Judging Team A Asterisk indicates Trainee is in first 12 months of research training Judging Team Alexandra Kuzyk and Nathan Bracey
Harris McCallum, Jessica
University of British Columbia
Resuscitation of shock using early standardized echocardiography is associated with improved survival
University of Toronto
Using Lung Progenitor Cells to Recellularize Lung Scaffolds
ECM Proteins Induce Favourable Morphology and University of Migration of Schwann Cells in Scaffolds for Nerve Saskatchewan Repair
Effect of combined sitagliptin and oligofructose therapy on glucagon-like peptide-1 secretion and gut microbiota in pre-pregnant diet-induced obese rats
University of Calgary
University of Tracheal Palpation to Guide Endotracheal Tube Saskatchewan Depth in Pediatrics
Community Assessment of Risk and Education for Atrial Fibrillation (CAR-AF)
Judging Team B Asterisk indicates Trainee is in first 12 months of research training
Poster judges: D. Sesath Hewapathirane and Adam Dmytriw
The impact of warfarin on the rate of progression of aortic stiffness in haemodialysis patients
University of Manitoba
Exploration of Contrast Agents for Functional Imaging Using Microwave Tomography
University of Western Ontario
Detection of galectin-3 and localization of advanced glycation end products (AGE) in human chronic skin wounds
University of Alberta
Resistance to HER-2 targeted therapies following spontaneous epithelial-mesenchymal transition in HER-2 positive luminal breast cancer cells
University of Alberta
Morphological and Behavioral Responses to a Western-Style Differ Between Wild-Type and IL10-/- Mice
University of Manitoba
Functional characterization of novel biomarkers in selecting for medulloblastoma phenotypes
Judging Team C Asterisk indicates Trainee is in first 12 months of research training Poster Judges: Alfred Basilious and Edward Liu
Krassioukov , Dmitri
University of Manitoba
Neuroglial proliferative and migratory suppression following paraventricular hemorrhage in the neonate rat - role of transcription factors
Levels of Evidence in Pediatrics: A Comparison of Top Medical Journals and General Pediatric Journals
Medical students’ attitudes and knowledge about harm reduction and access to health care for people who misuse substances
University of Ottawa
Evaluating the Use and Diagnostic Yield of CT Pulmonary Angiography to Exclude Acute
Hepatocellular carcinoma and treatment with sorafenib: A retrospective study of patients referred to a provincial cancer centre from 20032012
Evaluation of a novel strategy of Consultation in the Hematology Ambulatory Setting
1130 – 1215
Luncheon – Joe Doupe Concourse
1215 - 1310
‘AIDS and the Nervous system: From Desperation to Indifference’ Keynote Speaker Dr. Chris Power, CRC in Neurological Infection and Immunity, University of Alberta Gaspard Theatre (Theatre A)
1315 - 1415
Professional Development Workshop: ‘Career Options Utilizing my Research Skills– What if I don’t wish to be a Professor?’ Moderator Dr Kent HayGlass, Panelists: Dr. Michael Williams (Patent Agent, Ade and Co, Manitoba); Dr. Laura Wilson (Director of Grants, Barts and the London Charity, United Kingdom) ; Dr. Peter Nickerson (Flynn Family Chair in Renal Transplantation, Associate Dean (Research), University of Manitoba) Gaspard Theatre (Theatre A)
1415 - 1525
Poster Discussion Session 3 – Brodie Centre Mezzanine Poster presentation 3 minutes, 3 minutes discussion (6 minutes in total).
Judging Team A Asterisk indicates Trainee is in first 12 months of research training Judging Team Alexandra Kuzyk and Nathan Bracey
Hospitalization with Delirium in Older Adults from Standard Dose Histamine2-Receptor Antagonists: A Population-Based Study
University of Manitoba
Trends in Revision Rates and Reasons For Revision – Information from a Regional Health Authority Joint Replacement Registry
Intramedullary spinal cord cavernomas: a systematic review
Efficacy and safety of different bridging regimens of parenteral anticoagulation after mechanical valve replacement
University of Saskatchewan
COPD Care in the Acute Care Setting Clinician's and Patient's Perspectives
Judging Team B Asterisk indicates Trainee is in first 12 months of research training Poster judges: D. Sesath Hewapathirane and Adam Dmytriw
How do we treat acute immune thrombocytopoenia (ITP) in the Maritime provinces?
University of Calgary
Distinct Cell Signaling Mechanisms Drive TNFÎą and IFNÎł-Induced Transcriptional Downregulation of Aquaporin 3 RNA Expression
University of Alberta
Uncovering the Role of Topoisomerase IIBeta Binding Protein 1 in DNA Replication Stress Response
Faria Crowder, Monica
University of Calgary
Development of a Microbiome Approach to Sepsis and Application of Novel Methods to Whole Blood
University of Ottawa
A novel combined approach using genetics and clinical variables to predict high onclopidogrel platelet reactivity
Judging Team C Asterisk indicates Trainee is in first 12 months of research training Poster Judges: Alfred Basilious and Edward Liu
University of Smith, Paxton British Columbia
Quantitative Evaluation of Two Leading Open-Source Image Registration Tools for Automatic Volumetry of the Corpus Callosum
A Longitudinal Study of the Relationship of Hopelessness to Excessive Drinking Among University Students
Risk factors for falls and fragility fractures in community-dwelling seniors
University of Saskatchewan
Direct Admissions to the Orthopaedic Ward from the Emergency Department: A Canadian Survey of Attitudes and Trends
University of Toronto
Factors Affecting Cancer Patient Willingness to Provide Biological Samples for Pharmacogenomic and Genetic Testing
ATP-Binding Cassette Transporter A1 (ABCA1) Associated with Markers of Instability in Human Atherosclerotic Carotid Plaque
1530 – 1700 Session 4 – Lightning Oral Presentations Procurity Lecture Theatre, Apotex Centre, Main Floor; 6 minute oral presentation, 4 minute questions, 8 in total. Chairs: Joanna Slusar and Jennifer LeMessier Judges: Dr. Christine Zhang and Samantha Pauls Student
University of British Columbia
Clonal tracking studies reveal heterogeneity in mammary stem cell potential – implications for breast cancer treatment
Development of a Targeted Microbubble Contrast Agent for the Molecular Imaging of Endothelial Progenitor Cell Engraftment
University of Toronto
Targeting fatty acid metabolism: a novel chemosensitizing approach for castration-resistant prostate cancer
University of Saskatchewan
Epidemiology of spinal infections: a chart review of osteomyelitis, discitis, & epidural abscesses
Bridging the gap between open and minimally invasive pancreaticoduodenectomy: the hybrid approach
Wang, Jay Ching-Chieh
University of BC
Effects of AMD-associated factors: CFH Y402H polymorephism, age and drusen, on ocular
vitreoretinal environment Kuzyk, Alexandra
University of Manitoba
Novel Biomarkers in Pediatric Neuroblastoma
University of Manitoba
A longitudinal study on the value of the methacholine challenge test as a diagnostic aid for asthma in high-risk adolescents
Preparation for departure from Brodie Centre to social event at Lower Fort Garry. Dress for outdoors.
1730 - 1750
One bus departs from the front of Brodie Centre for social evening, CSHRF and CNMSRS dinner and mixer. Bus departs promptly by 17:50.
2230 - 2330
Participants return via bus directly to the Canad Inns HSC. Busses leave at 2230 and 2330.
Lightning Oral SESSION 1 Procurity Lecture Theatre, Apotex Building Main Floor, Room 164 8:25 â€“ 10:00 a.m. Wednesday, June 5th, 2013
Intrauterine growth restriction (IUGR) and stem cell integration: a novel cerebral palsy rodent model. Alfred Basiliousa, Shanojan Thiyagalingama, Stuart Faulknera, Crystal Ruffa, Michael G. Fehlingsa-c aDivision of Genetics and Development, Toronto Western Research Institute, b Krembil Neuroscience Centre, University Health Network, c Division of Neurosurgery, University of Toronto Rationale: Cerebral palsy (CP) is the most common pediatric neurodevelopmental physical disability, with estimated lifetime costs/child at $1.5 million. Perinatal hypoxia ischemia, and inflammation are major causes of CP. However, premature infants constitute the largest etiologic subgroup of children wionstrating periventricular leukomalacia and subsequent diplegia. Preferential damage to susceptible oligodendrocyte progenitor cells that produce myelin are a key target for cellular therapy. Objectives: Development of a relevant animal model of IUGR related CP and a study of outcomes of stem cell integration in this model. Methods: Bilateral uterine artery ligation of pregnant female rats (E20) induced IUGR. Neural precursor cells (NPC) (n=6) or media (n=6) were injected into the corpus callosum at P21. Behavioural deficits were evaluated using cylinder testing, catwalk, and ladder walk weekly and gross anatomical deficits were assessed every 3 weeks using MRI. Immunohistochemistry, involving H&E (gross histology), LFB (myelination), GFAP (astrocytic activation), Olig2/MAG/MPB (oligodendrocyte differentiation), and NF200 (neurogenesis) were used to examine extent of cellular damage and repair. Results: IUGR animals did not show clear gross forelimb deficits on cylinder test or gross hindlimb deficits on ladder walk. On catwalk, IUGR animals demonstrated shorter hindlimb stride length (p<0.001) at 2 and 8 weeks. At 6 weeks, IUGR animals demonstrated longer maximum contact (p<0.05) and shorter base of support (p<0.02) compared to sham. MRI demonstrated qualitative thinning of the white matter tracts in the corpus callosum of experimental animals. HistologicallyOn histology, the corpus callosum occupies significantly less brain area in IUGR+Media (p < 0.017) and IUGR+NPC (p < 0.025) compared to SHAM. In both IUGR groups, weight was significantly correlated with the percent of brain area occupied by corpus callosum (p < 0.045). Conclusions: IUGR behavioural and MRI findings mirror subtle deficits found in spastic diplegia. Histology has revealed that indeed IUGR results in decreased white matter within the corpus callosum as seen in CP patients. Thus, IUGR represents a promising representation of clinical CP.
Funding: CIHR, CREMS email@example.com 17
Inflammasome-Independent Nlrp3 Regulates Cardiac Myofibroblast Differentiation and Fibrosis Nathan A Bracey1, H Christopher Meijndert1, Paul W Fedak1, James R Wright, Jr3, Paul L Beck2, Daniel A Muruve2, Henry J Duff1 1Libin Cardiovascular Institute, 2Department of Medicine, 3Department of Pathology Rationale- Nlrp3 is a cytoplasmic pattern recognition receptor that signals for activation of the inflammasome, a multi-protein complex triggering Caspase-1 dependent cytokine release and inflammation. While much is known regarding the role of Nlrp3 in innate immune cells, little is known about its function in the heart. Objective- We sought to determine the expression, localization and function of Nlrp3 in cardiac fibroblasts (CFs) to identify its potential role in cardiovascular disease. Methods- In vitro, primary CFs isolated from human or murine cardiac tissue were stimulated with TGF-β or angiotensin II (angII) and assessed for differentiation to wound healing myofibroblasts. As an in vivo model, WT and Nlrp3-/- mice were administered angII (1.5mg/kg/day) for 28 days to induce hypertensive cardiac fibrosis. Results- Nlrp3 was expressed in left ventricular tissue from patients with end stage heart disease and localized to mitochondria in human CFs. Nlrp3 was required for activation of CFs in response to both TGF-β and angII in vitro. Nlrp3-/- CFs showed a reduced response to angII and TGF-β and did not form α-smooth muscle actin (α-SMA) stress fibers. Interestingly, Caspase-1 was dispensable as Caspase-1-/- CFs responded similar to WT, supporting an inflammasome-independent mechanism. Despite preserved Erk1/2 and AKT signaling, Nlrp3-/CFs revealed significantly impaired receptor-associated Smad (r-Smad) activation, suggesting an alternative role for Nlrp3 in regulating fibrotic signal transduction. Only the central Nlrp3NACHT domain was required for r-Smad signaling in a Smad-dependent luciferase assay, as expression of the Nlrp3-PYD or LRR domains alone failed to augment r-Smad transcriptional activity. In vivo, Nlrp3-/- mice were protected against angII induced hypertensive cardiac fibrosis. Nlrp3-/- hearts displayed significantly reduced α-SMA and collagen-1 compared to WT following 28 days of angII, with fewer fibrotic regions containing myofibroblasts despite a similar degree of hypertension. Conclusions- Our results identify Nlrp3 as a critical regulator of cardiac fibrosis through noncanonical regulation of r-Smad-dependent myofibroblast differentiation.
Funding- AIHS MD/PhD Studentship firstname.lastname@example.org 18
The Impact of Experience on the Implicit Visuomotor Response Adam Dmytriw1, Cameron Hassall2, Suzan Nouwens3, Todd C. Handy3, Olav E. Krigolson2 1. Faculty of Medicine, Dalhousie University 2. Department of Psychology and Neuroscience, Dalhousie University 3. Department of Psychology, University of British Columbia Rationale: Viewing novel objects that afford action typically results in neural activation in premotor and parietal cortex. These cortical regions are associated with object grasping and manipulation. Previous research found that premotor and parietal cortex were activated when an individual passively viewed rock climbing holds with which they had no experience. In comparison, when expert rock climbers viewed the same climbing holds, no activation was observed in either the premotor or parietal cortices. Here, we sought to demonstrate that these marked differences are specifically due to a lack of motor experience with rock climbing holds for novice climbers, and that training would result in a decrease in activation in the premotor and parietal cortices. Methods: Ten participants passively viewed rock climbing holds and matched control objects (â€œblocksâ€?) which had similar visual characteristics but were not graspable. Participants underwent functional magnetic resonance imaging (fMRI) during object viewing. Following this, participants underwent four weeks of training with the climbing holds they had viewed. Subsequently, the participants again passively viewed the climbing holds while undergoing fMRI. Results: Behavioral analysis of the training data revealed motor learning. Specifically, participantsâ€™ ability to navigate a climbing wall with the viewed holds significantly improved in terms of falls, grasping errors, and climbing time with practice. Analysis of the fMRI data revealed activation in premotor, right parietal, and bilateral occipital cortices for climbing holds and blocks in the pre-training scan. Activation in the premotor and right parietal cortices for climbing holds decreased with training and was not present in the post-training scan. Conclusions: When an individual views graspable objects not previously seen, cortex associated with object manipulation tends to activate. We propose this reflects a speculative process of motor interaction with the object. We demonstrate the presence of this activation within the premotor and right parietal cortices, and more importantly that this activation decreases with motor experience. In sum, we believe that object viewing results in an implicit analysis of motor interaction as a precursor to actual object manipulation.
Funding: Dalhousie Medical Research Foundation, National Sciences and Engineering Research Council of Canada Adam.email@example.com 19
Cholesterol Efflux Capacity is Inversely Associated with Severity of Carotid Atherosclerosis and Increases with Time Since Cerebrovascular Event RJ Doonan, A Hafiane, J Gorgui, J Genest, SS Daskalopoulou Introduction: HDL is thought to exert its atheroprotective role by promoting cholesterol efflux from lipid-laden macrophages. Cholesterol efflux capacity (CEC) has been shown to be inversely associated with carotid intima-media thickness and presence of coronary artery disease. We assessed the hypothesis that CEC is associated with severity of carotid atherosclerosis and with cerebrovascular symptomatology. Methods: Symptomatic (n=114) and asymptomatic (n=41) patients with carotid stenosis were recruited from Vascular Surgery at the Royal Victoria and Jewish General hospitals, Montreal, Canada. Carotid Doppler ultrasound was performed and stenosis (50-79%, 80-99%) was graded according to velocities. Detailed information on symptomatology obtained. A blood sample was collected on the day of the ultrasound; HDL was obtained by polyethylene glycol precipitation after depletion of apoB-containing lipoproteins. CEC was determined by incubating HDL in cAMP-stimulated J774 mouse peritoneal macrophages for 6 hours. Specific cholesterol efflux was obtained by subtracting total efflux from efflux in non-cAMP stimulated cells. Differences in CEC were assessed using linear regression according to 1) stenosis, 2) symptomatology and, 3) timing of symptomatology. Results: Compared to patients with 50-79% stenosis (n=31), patients with 80-99% stenosis (n=124) had significantly decreased CEC (beta=-2.23, P=0.04) after adjustment for age, sex, apoAI, and systolic BP. CEC was not significantly different between symptomatic or asymptomatic patients. However, in symptomatic patients CEC increased with increasing time since cerebrovascular event. Specifically, compared to 0-30 days (n=72), CEC was nonsignificantly increased 31-90 days since event (n=31, beta=1.64, P=NS), while increased significantly â‰Ľ 90 days since event (n=11, beta=4.48, P=0.01), after adjustment as described above. Conclusion: These results suggest that CEC is inversely associated with severity of carotid stenosis and that CEC increases with increasing time since symptomatic event. This may be related to remodeling of HDL during the acute phase reaction after a recent ischemic event.
Early-life seizures persistently alter visual brain circuit development via neural activitydependent synaptotropic mechanisms. D Sesath Hewapathirane, Xuefeng Liu, Simon Chen, Wesley Yen, Parisa Karimi Tari, Shay Neufeld and Kurt Haas. Brain Research Centre and the Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, Canada. Rationale: Early-life seizures are highly prevalent, occurring mainly during the first years of life. Unfortunately, this is a critical period of brain maturation where precisely patterned neural activity directs the formation and refinement of complex circuits. This work examined whether abnormal and excessive neuronal activity associated with seizures interferes with normal neural circuit development. Methods: For these experiments we developed and characterized a unique model of developmental seizures based on the albino Xenopus laevis tadpole. Due to this organism’s transparency, when combined with two-photon in vivo time-lapse fluorescence microscopy, this system confers the unprecedented ability to examine the effects of seizures on neuronal growth and circuit function—during a seizure event—within the intact unanaesthetized developing brain. Single-cell electroporation was employed to fluorescently label and functionally manipulate individual optic tectal neurons within the otherwise unaltered brain. Results: We find that developmental seizures persistently alter retino-tectal circuitry complexity, producing a lasting inhibition of dendritic arborization and reduction in excitatory synaptogenesis. These effects are downstream of excessive excitatory glutamatergic input, since individual neurons with reduced AMPA receptor-mediated neurotransmission are protected from seizure-induced inhibition of arbor growth. Examination of dynamic dendritic growth reveals two distinct yet opposing effects of seizures, the rapid destabilization and retraction of dendritic elements generated prior to seizure onset, and the hyperstabilization of dendritic elements generated during seizure episodes—suggesting that seizures destabilize pre-existing endogenous circuitry and promote the formation of aberrant circuitry. Strikingly, we find that seizure-induced hyperstabilization of dendritic elements could be blocked by reducing the expression of the protein kinase PKMzeta, a kinase implicated in late-phase glutamatergic synapse long-term potentiation and synaptotropic dendritogenesis. Conclusions: These experiments are the first to examine seizure-induced effects on neural network maturation within the intact awake developing brain. Our findings identify morphological substrates potentially underlying neurological dysfunction associated with early-life seizures and, importantly, identify a molecular pathway which can be targeted to protect the brain from the observed deleterious changes. Ongoing experiments are investigating circuit function by recording neural calcium responses from the intact optic tectum in response to visual stimulation, and using visual-cue based avoidance learning assays in freely-swimming tadpoles.
Funding: CIHR, Savoy, BCIC, SRCF, UBC. Presenter can be contacted at firstname.lastname@example.org 21
The Neuroprotective Compound P7C3 Enhances Functional Recovery Following Neonatal Nerve Injury in a Dose-Dependent Manner Edward H. Liu1, Stephen W.P. Kemp1, Andrew A. Pieper2, Matthew D. Wood1, Mark Szynkaruk1, Krisanne N. Stanoulis1, Tessa Gordon1, & Gregory H. Borschel1 1 Division of Plastic Surgery, The Hospital for Sick Children and the University of Toronto, Toronto, Ontario, Canada 2Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, USA Rationale: Sciatic nerve injury in neonatal rats results in a significant loss of both motor and sensory neurons, leading to impaired function and locomotor ability in adulthood. The majority of these neurons die rapidly following nerve injury through a glutamate induced, excitotoxic apoptotic mechanism. The neuroprotective compound P7C3 has been previously shown to display proneurogenic, neuroprotective properties following injury to the central nervous system. P7C3 exerts its proneurogenic activity by protecting newborn neurons from apoptosis. However, this central neuroprotective agent has not yet been tested in a model of neonatal peripheral nerve injury. Objectives: We sought to assess the possible neuroprotective effects of daily administration of P7C3 for a two-week period, and examined both axonal and Schwann cell (SC) regenerative properties following unilateral sciatic nerve crush at postnatal day 3 (P3) in neonatal rats. Methods: Animals were randomly assigned to one of seven experimental groups: 1 mg/kg P7C3 (Group 1); 5 mg/kg P7C3 (Group 2); 10 mg/kg P7C3 (Group 3); 20 mg/kg P7C3 (Group 4); vehicle controls (Group 5); normal controls (Group 6); inactive analogue (Group 7). In the first set of experiments, both the spinal cord and dorsal root ganglion (DRG) cells were characterized following retrograde labeling of the sciatic nerve with FluorGold (FG) at 1 month following initial injury. The second set of experiments analyzed behavioral recovery of both overground and skilled locomotion (ladder rung task, walking track), following P7C3 administration. Endpoint functional analysis consisted of electrophysiological and myological assessments, including both mean twitch and tetanic forces, wet muscle weights (gastrocnemius, tibialis anterior, soleus, extensor digitorum longus, plantaris), and motor unit number estimation (MUNE). Results: Animals directly administered P7C3 over a two week period followed a dose dependent regenerative response, with an optimal threshold effect occurring at a dose of 20 mg/kg. At this dose, improved motor and sensory regenerative properties were increased to approximately 80% of normal. Results of the behavioural recovery and functional analysis also indicate significant differences between treatment groups. Conclusion: This study demonstrates the neuroprotective properties of P7C3 following sciatic nerve injury in a neonatal model.
Funding: CIHR Email: Edward.Liu@medportal.ca
The developmentally conserved Bmi1-FoxG1-p21 axis regulates tumor heterogeneity and self-renewal in medulloblastoma brain tumour-initiating cells. Branavan Manoranjana,b,c, Robin M. Hallettb,d, Chitra Venugopalc, Nicole McFarlanec, John A. Hassellb,d, Sheila K. Singhb,c,e aMichael G. DeGroote School of Medicine, bDepartment of Biochemistry & Biomedical Sciences, cMcMaster Stem Cell & Cancer Research Institute, d McMaster Centre for Functional Genomics, eDepartment of Surgery, McMaster University, Hamilton, Ontario, Canada Rationale: Brain tumors represent the leading cause of childhood cancer mortality, of which medulloblastoma (MB) is the most frequent malignant pediatric brain tumor. Brain tumourinitiating cells (BTICs) characterize a small fraction of tumour cells that have the ability to initiate and maintain tumour growth, unlike all other cells of the bulk tumour mass. The rarity of BTICs may explain why current gene expression platforms have not detected stem cell genes in aggressive MBs, as current arrays profile the bulk tumour mass without considering the heterogenous cellular and genomic landscape of a tumour. Methods: We investigated the differential stem cell gene expression profile in 325 primary human MBs. Using a subsequent series of step-wise knockdown, overexpression, in vitro, in vivo, and chromatin immunoprecipitation (ChIP) analyses we then assessed the functional relevance of two genes, Bmi1 and FoxG1, which were preferentially expressed in poor-outcome MBs. Results: We show Bmi1 and FoxG1 to co-operatively regulate in vitro and in vivo self-renewal, a critical property through which stem cells give rise to an identical daughter cell. Our ChIP data demonstrates that a differential transcriptional regulatory mechanism exists within distinct cell populations of the bulk tumour, as Bmi1 and FoxG1 show reciprocal promoter binding only in CD15+ MB BTICs. Our data further suggests this difference to repress the cell cycle inhibitor, p21, in CD15+ MB BTICs, permitting extensive self-renewal and proliferation in this cell fraction, while CD15- cells are maintained through p21 signaling. Conclusion: The aberrant activation of the Bmi1-FoxG1-p21 axis in MB may be considered as development gone awry since this pathway is also active during neurogenesis. Aside from implicating developmental pathways in oncogenesis, we have also demonstrated the importance of studying cancer at a cellular level as distinct differences in subsets of tumour cells may not otherwise be appreciated in todayâ€™s era of bulk tumour genomic profiles.
Funding: CIHR, OICR email@example.com 23
Slit2/Robo-1 signaling in monocyte recruitment and adhesion. Ilya Mukovozova,b, YW. Huanga, GY. Liua, S. Patela , Y. Sokolskya and L.A. Robinsona,b a
Cell Biology Program, The Hospital for Sick Children Research Institute, Toronto, ON
Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, ON
BACKGROUND: A hallmark of atherosclerosis is vascular inflammation characterized by recruitment of circulating lymphocytes and monocytes. Inhibiting monocyte recruitment partially prevents atherosclerosis and its clinical manifestations. However, the redundancy in chemoattractant pathways means that interruption of a particular pathway may result in another pathway assuming its function. Localized general chemoattractant blockade could be a useful strategy. The Slit family of secreted proteins, together with their transmembrane receptor Roundabout, repel migrating neurons during central nervous system development. Recently, Slit2 was shown to inhibit chemotaxis of diverse cell types, including vascular smooth muscle cells and circulating neutrophils, towards diverse chemoattractants. PURPOSE: The effects of Slit2 on monocyte recruitment and adhesion to activated endothelial cells under shear flow, and the corresponding intracellular signaling pathways, were investigated. METHODS: Monocyte chemotaxis in vitro was tested using transwell migration assays, while in vivo recruitment was investigated using a murine model of irritant-induced peritonitis. Adhesion assays under shear flow were utilized to investigate the effect of Slit2 on monocyte capture, rolling and arrest. Monocyte adhesion to both activated endothelial monolayers and immobilized endothelial adhesion molecules, including ICAM-1 and VCAM-1, was investigated. Rac1Q61LGFP (Constitutively active) transfected U937 cells were utilized to investigate the role of Rac1 in monocyte adhesion stabilization. LDV-FITC binding assays were performed to investigate possible slit2-induced changes in α4β1 integrin affinity. Pulldown assays were performed to investigate the effects of Slit2 on SDF-1α-mediated Rac1 and Cdc42 activation. RESULTS: Slit2 decreased monocyte chemotaxis (p<0.01) and monocyte recruitment to the peritoneal cavity (p<0.001). Slit2 also inhibited monocyte adhesion to stimulated endothelium and immobilized endothelial adhesion molecules under static conditions (p<0.01). Although monocyte rolling and capture was not affected under shear flow, Slit2 inhibited the stabilization of firm monocyte adhesion (p<0.01). The inhibition of firm adhesion stabilization was rescued by transfection with Rac1Q61L-GFP. Finally, Slit2 inhibited SDF-1α-mediated α4β1 integrin affinity up-regulation and SDF-1α-induced activation of Rho GTPases Cdc42 and Rac1. CONCLUSIONS: These experiments demonstrate that Slit2 inhibits monocyte recruitment and adhesion. This may allow the use of Slit2 as a novel anti-inflammatory therapy to locally target the leukocyte adhesion cascade and prevent chronic monocytes infiltration in atherosclerotic lesions.
SESSION 2 Poster Discussion Brodie Centre Mezzanine 10:00 â€“ 11:30 a.m. Wednesday, June 5th, 2013
Resuscitation of shock using early standardized echocardiography is associated with improved survival Hussein D. Kanjib, Jessica McCallumc, Demetrios Sirounisab, Ruth MacRedmondab, Robert Mossc; John H Boydab aCritical Care Research Laboratories, Heart + Lung Institute at St. Paul's Hospital University of British Columbia, Vancouver, BC, Canada, bDepartment of Critical Care Medicine, University of British Columbia, Vancouver, British Columbia, Canada cHeart Centre, St. Paulâ€™s Hospital, Vancouver, BC, Canada Rationale: There is currently no standardized method to resuscitate patients presenting with shock. We compared a strategy of Early Standardized Echocardiography (ESE) versus conventional management in patients presenting with undifferentiated shock. Objectives: To assess the impact of an early-standardized echocardiography (ESE) hemodynamic assessment in patients with vasopressor-dependent shock. Methods: This study took place in single center quaternary-level hospital in Vancouver, Canada. ESE-guided resuscitation began January 4th, 2012. ESE was performed by one of three Intensivists with advanced training in echocardiography. Recommendations for fluid and inotropic management were based upon the results of the ESE. 74 consecutive patients were referred to the critical care service with shock and had treatment guided by an ESE performed using a hand-held device (V-Scan, GE Healthcare). 104 Patients resuscitated for shock prior to January 2012 constituted our standard management group. The primary outcomes were survival, fluid prescription during the first four days of admission, and days alive and free of mechanical ventilation, renal support and vasopressors during 28 days. Results: A recommendation to restrict fluid administration was made in 51 (69%) patients and addition of inotropic support was suggested in 12 (16%) patients. Significant valvular pathology was identified in 14 (19%) patients and 29 (40%) patients were deemed to have moderate to severe cardiac dysfunction. Patients receiving ESE had improved 28-day survival (73% vs 58%, p=0.003), more days alive and free of vasopressors [23 (6.0-25) vs 19 (0-24), p = 0.04] and mechanical ventilation [22 (7.0-26) vs 16 (0-22), p<0.001] compared to standard management. Four day fluid balance was significantly higher in the standard management cohort [4.0(1.7-7.9) Liters vs 12 (6.2-18) Liters, p< 0.001]. Conclusions: ESE-guided resuscitation improves survival in shock. A prospective randomized control trial is required to verify these results.
Funding: CIHR, National Sanitorium Association, Michael Smith Foundation for Health Research firstname.lastname@example.org 26
Using Lung Progenitor Cells to Recellularize Lung Scaffolds Mostafa Fatehia, Lily Guoab, Thomas K. Waddella,b aDivision of Thoracic Surgery, Latner Thoracic Surgery Research Laboratories and bMcEwen Centre for Regenerative Medicine, University of Toronto, Toronto General Hospital Introduction: Transplantation remains the only truly curative intervention in the end-stage of many lung diseases. However, like all other transplanted organs, there is a serious and chronic shortage in donated lungs. It is therefore imperative to develop novel therapies for acute injury or chronic degenerative conditions. Of particular interest is research in the application of stem cells or progenitor cells in lung regenerative medicine. To advance such therapies, however, we require a detailed understanding of cell proliferation and differentiation within various environments. Objectives: We assessed the capacity of progenitor cells to proliferate and differentiate in decellularized murine lung scaffolds. Moreover, the differentiation of cells within the scaffold was compared to the differentiation of similar cells cultured on other substrates such as Matrigel. Methods: Murine lungs were decellularized using detergents and NaCl. Decellularized matrices were compared with normal lungs using histological staining and DAPI staining. The levels of various ECM constituents were also quantified and compared between the lungs and scaffolds. Cell proliferation was assessed by Ki-67 staining and by real time PCR. Finally, the expression of various cell surface and cytoplasmic proteins was assessed using immunofluorescence. Results: These comparisons confirmed the absence of cells in the decellularized scaffolds but also the partial loss of collagen, elastin and proteoglycans. The lung scaffolds supported cell growth when cells were reintroduced into the lungs through the trachea. Discussion: In addition to improving our understanding of the interactions between cells and their surrounding matrix, findings from this study may ultimately improve the prospect of cell-based therapies in the lung.
ECM Proteins Induce Favourable Morphology and Migration of Schwann Cells in Scaffolds for Nerve Repair Adam McInnes1, Ajay Rajaram2, Daniel Chen2,3, David J. Schreyer2,4 1 College of Medicine, University of Saskatchewan; 2 Division of Biomedical Engineering, University of Saskatchewan; 3 Dept. of Mechanical Engineering, University of Saskatchewan; 4 Dept. of Anatomy and Cell Biology, University of Saskatchewan Rationale The orientation and morphology of Schwann cell in the bands of B체ngner are crucial for guiding regenerating axons in damaged peripheral nerves. Alginate scaffolds have been used as conduits for the repair of injured peripheral nerves. Although Schwann cells can survive and multiply within this hydrogel, they do not have favourable morphology. Most extracellular matrix (ECM) components and growth factors can be contained within alginate scaffolds. This study investigates the inclusion of these ECM proteins in alginate and analyzes the morphology and migration of Schwann cells within the alginate scaffolds. Methods A suspension of rat Schwann cell-line cells (RSC96) was mixed with alginate (2% w/v). Laminin and/or fibronectin was added to the alginate at a final concentration of 0.0125 mg/ml. The alginate-cell suspensions were dispensed as square contour patterns into a crosslinking solution containing calcium chloride. The scaffolds were rinsed with 25 mM HEPES buffer and cultured in DMEM + 10% FBS solution for a period of 15 days at 37째 C and 5% CO2. At the end of the study the scaffold patterns were stained using fluorescent dyes. Results It was observed that the Schwann cells migrated and replicated over time. In alginate scaffolds without ECM proteins, Schwann cells adhered to each other and formed clumps. The addition of fibronectin influenced the morphology and migration of Schwann cells within alginate, inducing their typical long fusiform bipolar morphology and organized patterns of growth. The cellular morphology in the scaffolds containing laminin was less organized than the cells in fibronectin scaffolds. In the laminin+fibronectin containing scaffolds, the Schwann cells migrated to form linear 'bands', but were not as well organized or consistent. Conclusion These preliminary results substantiate the importance of ECM proteins in scaffolds for tissue repair. The morphology and migration of Schwann cells in 3D hydrogel cultures are more favourable in the presence of ECM proteins. Further work will include the fabrication of scaffold patterns with concentration gradients of Schwann cells and ECM components. As alginate hydrogels are not entirely favourable for 3D-cell cultures, the addition of hyaluronic acid and/or collagen could be more favorable.
Funding: SHRF, UofS CoM email@example.com 28
Effect of combined sitagliptin and oligofructose therapy on glucagon-like peptide-1 secretion and gut microbiota in pre-pregnant diet-induced obese rats Amanda J. Eslinger and Raylene A. Reimer. Faculty of Medicine; Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB T2N 1N4
Maternal obesity can predispose offspring to increased adiposity and impaired glucose tolerance later in life. Consequently the period prior to conception offers a unique opportunity for the preemptive treatment of obesity with a goal of reducing programmed risk of obesity and type 2 diabetes in offspring. The gut hormone glucagon-like peptide-1 (GLP-1) acts in vivo to increase insulin secretion, slow gastric emptying and enhance satiety. Compounds that enhance GLP-1, like the prebiotic fiber oligofructose (OFS), or prolong the action of endogenous GLP-1, such as the DPP-IV inhibitor Sitagliptin, are potentially useful treatments for prepregnancy obesity. The purpose of this study was to: 1) examine the effects of combined dietary/pharmacological therapy aimed at maximizing active GLP-1 in a pre-pregnant obese model; and 2) examine potential protective effects in offspring of these dams. This abstract provides details on the first objective. Female diet-induced obese Sprague-Dawley rats (n=52) were randomized to 1 of 4 treatments for 8wk: 1) AIN-93M; 2) OFS; 3) AIN-93M+Sitagliptin; 4) OFS+ Sitagliptin. Three reference groups were included: high fat, sucrose (HFS, obese control), lean control, and caloric restriction (CR, matched weight loss to group 4). The primary outcomes were body weight, blood glucose and gut microbiota measured in fecal matter. Rats fed HFS gained the most weight (p<0.05). Obese females treated with CR and OFS+Sitagliptin achieved a post-treatment body weight similar to lean controls but AIN-93M and Sitagliptin did not (p<0.05). OFS and OFS+Sitagliptin increased bififobacteria (p<0.001) and decreased the %Firmicutes (p=0.03) compared to all other groups. C. leptum was increased in HFS rats (p=0.016) compared to OFS and OFS+Sitagliptin. Total bacteria were decreased in HFS compared to all other groups (p=0.04). The combination therapy attenuated weight gain to the greatest extent. Use of OFS as an adjunct to Sitagliptin appears valuable given that the Sitagliptin group gained significantly more weight than OFS+Sitagliptin. Both OFS and OFS+Sitagliptin exhibited microbial profiles associated with a lean phenotype. It is anticipated that the benefits of these strategic prepregnancy treatments will provide protection and reduce detrimental programming in offspring.
Supported by ACHRI Child and Maternal Health CIHR Training Program firstname.lastname@example.org 29
TRACHEAL PALPATION TO GUIDE ENDOTRACHEAL TUBE DEPTH IN PEDIATRICS Dr. Jonathan Gamble, Dr. William McKay, Jennifer O’Brien, Andrew Wang, Kinsha Yip, Dr. Mateen Raazi, Dr. Chris Plewes Rationale: Endotracheal intubation is a common life-saving procedure. Proper ETT position is achieved when the distal tip is mid-trachea. Pediatric Advanced Life Support (PALS) teaches ETT insertion depth be guided by a measurement of the length of the tube at the teeth, which is not always reliable. X-ray imaging is often used to confirm ETT placement; however, X-ray is time consuming, expensive, and exposes to radiation. Objectives: We proposed a study to evaluate the utility of palpitation of the ETT tip moving down the trachea to guide appropriate final ETT position. Methods: A convenience sample of 50 pediatric patients 2 or more years of age undergoing elective surgeries requiring intubation were recruited in this interventional cohort study. During intubation an investigator palpated the trachea with three finger tips side by side extending upward from the suprasternal notch, and the anesthesiologist was instructed to advance the inserted ETT slowly until palpated at the sternal notch. The palpator stated the certainty of palpating the ETT as “strongly felt”, “weakly felt”, or “not felt”. The final ETT position was determined by bronchoscopy and categorized as “ETT too shallow” (tip in proximal ¼ of trachea); “ETT too deep” (tip distal ¼ of trachea); and “ETT placement satisfactory” (between those extremes). Results: 30 boys and 20 girls with a mean age 4.08 years (SD 1.77 range 2-10) were recruited. In all patients the ETT was palpable at the sternal notch with 46/50 strongly palpable and 4/50 weakly palpable. The experimental methods lead to satisfactory ETT placement in 49/50 patients, too shallow in 0/50 patients and too deep in 1/50 patients. These results were compared to the PALS method where satisfactory placement would have been 42/50 patients (p=0.003). Number Needed To Treat (NNT) was six to achieve an improvement over the PALS method. Conclusions: Our results demonstrate that tracheal palpation, a technique that requires no equipment and takes only a few seconds to perform, has excellent clinical performance to determine appropriate ETT depth in children. This technique better predicts appropriate ETT depth than the common used PALS formula.
Funding: University of Saskatchewan College of Medicine email@example.com 30
Community Assessment of Risk and Education for Atrial Fibrillation (CARE-AF) Aniket Hooda1, Nicholas Giacomantonio 2 and the HeartLand Tour1 Faculty of Medicine, Dalhousie University, Halifax, NS 2Community Cardiovascular Hearts in Motion, Division of Cardiology, Capital Health, Halifax NS
Introduction: Atrial Fibrillation (AF) is the most common chronic cardiac arrhythmia and major risk for thromboembolic events, heart failure and poor quality of life. Previous evidence suggests increasing AF incidence not just because of age but also because of rising modifiable risk factors. There is little prospective data on the future risk of developing AF. Methods: We compared future AF risk between individuals participating in the 2012 Heartland Tour (HLT group â€“ www.HeartLandTour.ca ) with the general population. We utilized a recently developed Framingham Model for short term -10 year- AF risk (FAF risk score) Results: In 139 eligible participants of the HLT, the average FAF risk score was 2.63% compared to 6.83% in 169 members of the general population (p<0.001). Activity levels of the two groups were standardized using Godin-Shephard Leisure Time Exercise Score (GS score). Average HLT cohort score was 51.6 versus 30.0 for the general population (p<0.04). A GS score of â‰Ľ24 is associated with tangible health benefits. This was found in 193 study participants, and they had an accompanying FAF score of 3.73%. Those with a GS score of less than 24 had an average FAF score of 7.58%. After standardizing for cardiac risk factors including age the difference in these FAF scores remained significant (p=0.0146).
Conclusions: To the best of our knowledge, this is the first study to quantitatively show that moderate physical activity may reduce the future risk of developing AF by as much as 50% and is the first study to prospectively utilize this FAF risk model in a population health community setting. Organized heath events as the HLT have the opportunity to reduce future AF risk and should be promoted and supported for this activity. However, we cannot exclude the possibility that such organized events have a selection bias towards more active and subsequently lower risk populations, which is defeatist of their stated objectives in motivating and changing behaviors of those at most risk. Further study is required to expand this assessment in other health-oriented events that promote physical activity and to prospectively evaluate the role of physical activity and programs such as Cardiac Rehabilitation towards AF prevention in at risk populations.
The impact of warfarin on the rate of progression of aortic stiffness in haemodialysis patients Aurélie Poulin, Fabrice Mac-Way MD, Mihai Silviu Utescu MD MSc, Karine Marquis PhD, Simon Desmeules MD, Marcel Lebel MD, Mohsen Agharazii MD Rationale: Cardiovascular disease is the leading cause of death in patients with chronic kidney disease (CKD). Aortic stiffness and calcification are now known non-traditional cardiovascular risk factors in CKD. Studies have shown an association between vascular calcification and warfarin therapy, which inhibits Matrix Gla protein (an anti-calcifying protein) carboxylation. However, the association between warfarin and arterial stiffness is still unclear. In this context, we hypothesized that warfarin therapy results in enhanced progression of aortic stiffness in hemodialysis patients. Methods: This is a case-control study with a longitudinal follow-up of haemodialysis patients. 18 patients treated with warfarin were matched (according to age and cardiovascular disease) with 54 patients without warfarin. Aortic and brachial stiffness were determined by measurements of carotid-femoral and carotid-radial pulse wave velocities (PWV), respectively, at baseline and after a mean follow-up of 1.2 years. Protein Induced by Vitamin K Antagonist-II (PIVKA-II) levels were determined in both groups. Results: Carotid-femoral PWV of both groups were the same at baseline (12.8±2.6 m/s and 12.8±3.1 m/s, p=0.795). After a mean follow-up of 1.2 years, carotid-femoral PWV (adjusted for BP) increased by 2339±597 mm/s in the warfarin group, while it only increased by 781 ± 206 mm/s in the control group (p=0.013). The median level (interquartile range) of PIVKA-II was 1000 (520-1004) ng/ml in the warfarin group and 3 (2–4.5) ng/ml in the control group (p<0.001). In a multivariate analysis, with adjustment for the duration of follow-up and changes in BP, warfarin was associated with enhanced progression of aortic stiffness (adjusted R2=0.429, p=0.006). In a similar analysis, levels of PIVKA-II were also associated with aortic stiffness progression (adjusted R2=0.429, p=0.015). The use of warfarin did not have any effect on brachial stiffness progression. Conclusions: This study shows that the use of warfarin in haemodialysis patients is associated with an accelerated progression of aortic stiffness, and at least, some of the effects of warfarin are mediated through interference with vitamin K metabolism. Considering that this group of patients is at high risk of bleeding and vascular calcification, the overall benefits and risks of warfarin therapy in this population should urgently be examined.
Exploration of Contrast Agents for Functional Imaging Using Microwave Tomography Cameron Kayea, Joe LoVetria, Amer Zakariaa and Anastasia Barana a Department of Electrical and Computer Engineering, University of Manitoba, Winnipeg, MB, Canada Rationale: Microwave tomography (MWT) or microwave imaging spectroscopy (MIS) has been studied as a promising low-cost portable alternative or complementary biomedical diagnostic technique for conventional soft-tissue imaging modalities for several years. The ability to quantitatively reconstruct unique, diagnostically useful properties of the tissue of interest (i.e. the permittivity and effective conductivity) at safe, non-ionizing frequency ranges without the need of a contrast agent has been among MWT's frequently quoted advantages, especially in the context of its most developed application in breast imaging. However, recent large-scale studies characterizing the ultra-wideband dielectric properties of freshly excised breast tissues have shown that the contrast between malignant breast carcinoma and normal fibroconnective/glandular tissue is inherently low, making it clear that this emerging technology could benefit from the use of exogenous contrast agents that selectively accumulate in cancerous tissues. This concession has spurred interest in the study of conventional and novel contrast agents in the field of microwave imaging. Methods: A broad study of contrast agents, including compounds traditionally employed in nuclear medicine procedures and other conventional anatomical imaging modalities, is conducted to assess their feasibility for microwave imaging. The search is expanded to explore not only tumour markers, but any organic or non-organic chemical compounds whose distribution within live tissues could yield useful functional, physiological information. Examples include potassium analogues (rubidium, cesium), tissue oxygenation markers (nitroxide radicals), and functionalized magnetic nanoparticles. Such chemical species with favourable complex permittivity over a frequency range of interest are preliminarily evaluated through 2D numerical imaging simulations. Results: A finite element contrast source inversion algorithm was used to invert synthetic contrast-enhanced breast and forearm data containing inclusions representing tumours. Prior information about the anatomy and the electrical properties of the breast (or forearm) model was incorporated through the use of a blind inversion before adding the contrast agent, which was simulated by increasing or decreasing the permittivity and conductivity of the tumours appropriately. Conclusions: Initial findings from this ongoing study show that detection of pathological inclusions in an anatomical region with a large amount of inhomogeneity is possible by simulating the use of a contrast agent.
Funding: CIHR, NSERC. firstname.lastname@example.org 33
Detection of galectin-3 and localization of advanced glycation end products (AGE) in human chronic skin wounds Daniel Pepe1, Christopher G Elliott1, Thomas Forbes2 and Douglas W. Hamilton1, 3* 1
Department of Anatomy and Cell Biology, 3Division of Oral Biology Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario 2 Division of Vascular Surgery, London Health Sciences Center, Victoria Hospital, London Ontario
Rationale: The matricellular protein galectin-3 (Gal-3) is upregulated in excisional skin repair in rats where it has been shown to modulate the inflammatory phase of repair. Recent research into kidney pathology has implicated Gal-3 as a receptor for advanced glycation end products (AGE), resulting in the binding and clearance of these molecules. AGEs are thought to contribute to defective skin repair in diabetic patients as well as a result of the normal aging process. Objectives: Assess the distribution and localization of Gal-3 and AGEs in human chronic skin wound tissue. Methods: Using immunohistochemistry, the localization of Gal-3 and AGEs in tissue isolated from chronic wounds and non-involved skin from the same patient was investigated. Results: Of the 16 patients from which tissue was isolated, 13 had type II diabetes, one had type I diabetes and 2 patients without diabetes were also examined. In non-involved dermis, Gal-3 was detected strongly in the epidermis and in the vasculature. However, at the wound edge and in the wound bed, the level of Gal-3 labelling was greatly reduced in both the epidermis and vasculature. Labelling of serial sections for Gal-3 and AGE demonstrated that where Gal-3 immunoreactivity is reduced in the epidermis and vasculature, there is a concomitant increase in the level of AGE staining. Interestingly, similar labelling patterns were evident in diabetic and non-diabetic patients. Conclusions: The results from our study demonstrate an inverse correlation between Gal-3 and AGEs localization, suggesting that Gal-3 may protect against accumulation of AGEs in wound healing.
Funding: CIHR, SRTP email@example.com 34
Resistance to HER-2 targeted therapies following spontaneous epithelial-mesenchymal transition in HER-2 positive luminal breast cancer cells David Lesniaka, Bassam Abdulkarimb aDepartment of Oncology, University of Alberta, Edmonton, Canada bDepartment of Radiation Oncology, McGill University, Montreal, Canada Resistance to trastuzumab, a rationally designed HER-2-targeting antibody, remains a major hurdle in the management of HER-2-positive breast cancer. Preclinical studies suggest the mechanisms of trastuzumab resistance are numerous. Unfortunately, the majority of these studies are based around HER-2-positive (HER-2+) luminal cell lines. The role of epithelial to mesenchymal transition (EMT), a genetic program that confers a basal phenotype, may represent a novel mechanism of escape for HER-2+ luminal cells from trastuzumab treatment. Here we investigated this possibility using a model of clonal selection in HER-2+ luminal breast cancer cells. Following a random isolation and expansion of subclones from SKBR-3 cell lines, several clones underwent a spontaneous EMT in-vitro. In addition to expression of conventional EMT markers, all SKBR-3/ EMT-clones displayed a predominant CD44+/ CD24- phenotype with decreased HER-2 expression and elevated levels of a β1-integrin isoform with a high degree of N-glycosylation. Treatment with a β1-integrin function blocking antibody, AIIB2, preferentially decreased the N-glycosylated form of β1-integrin, impaired mammosphere formation and restored epithelial phenotype in SKBR-3/ EMT-clones. Using this model we provide the first clear evidence that resistance to trastuzumab (and lapatinib) can occur spontaneously as HER2+ cells shift from a luminal to a basal phenotype following EMT. While the major determinant of trastuzumab resistance in EMT-clones is likely the down regulation of the HER-2 protein, our evidence suggests that multiple factors may contribute, including expression of N-glycosylated β1-integrin.
MORPHOLOGICAL AND BEHAVIOURAL RESPONSES TO A WESTERN-STYLE DIET DIFFER BETWEEN WILD-TYPE AND IL-10-/- MICE Evelina Pankiv, Christina Ohland, Karen Madsen Faculty of Medicine, University of Alberta. Edmonton, Alberta. Rationale: Interactions between gut microbiota and the host can influence both local and systemic immune and metabolic function. Specific microbial strains have key roles in modulating gut homeostasis, nutrient digestion and absorption, fat and energy metabolism, enteric nerve activity, and brain function. A western-style diet high in fat and refined carbohydrates is known to alter the gut microbiota, but the effects of this style of diet on behaviour are less well understood. In addition, whether a western-style diet has similar effects in the presence of underlying chronic inflammation is unknown. Objective: The aim of this study was to examine the effects of a high-fat/refined carbohydrate diet (HFD) on memory and anxiety in wild-type as well as IL-10-/- mice (mouse model of colitis). Methods: Mice were fed either standard mouse chow or a high-fat diet (HFD) for 21 days, and subjected to behavioural tests for memory and anxiety during the last week. Following sacrifice, intestinal morphology and corticosterone (a stress hormone) levels in the feces and serum were measured. Results: A HFD significantly decreased the cecum weight as well as fecal corticosterone levels in wild-type (WT), but not IL-10-/- mice. Further, WT mice on a HFD had a shorter time in the Latency to Step Down Test, which together with the fecal corticosterone levels suggest they have decreased anxiety levels. Interestingly, this finding was not mirrored in the IL-10-/- mice. Lastly, WT mice on a HFD were the only group to exhibit fewer errors in retrieval tasks following training in the Barnes Maze, indicating improved memory. The IL-10-/mice on the HFD again showed no evidence of this change. Conclusion: A diet high in fat and refined carbohydrates can significantly alter intestinal morphology and behaviour in normal healthy mice. However, mice exhibiting chronic colitis respond differently to the diet, suggesting disruptions between the gut and brain under conditions of chronic inflammation.
Funding: AIHS Author Contact: firstname.lastname@example.org 36
Functional characterization of novel biomarkers in selecting for medulloblastoma phenotypes. ac
Christopher Aiken, abcTamra Werbowetski-Ogilvie aDepartment of Physiology, bDepartment of Biochemistry and Medical Genetics, cRegenerative Medicine Program, University of Manitoba Rationale: Medulloblastoma (MB) is the most common primary pediatric brain cancer in North America. A rare subpopulation of cells within the tumor known as cancer stem cells (CSC) is thought to be responsible for tumor propagation and recurrence following treatment. To fully understand, isolate and target these cells, surface markers and their associated pathways need to be elucidated and their functional role in tumorigenesis understood. Recently, our laboratory has identified CD271/p75 neurotrophin receptor as a selective marker for higher self-renewing MB cells in vitro. Objectives: 1. To determine the tumorigenic potential of high vs low self-renewing MB subclones as well as CD271+ cells in vivo, 2. To screen MB subclones using high throughput flow cytometry screening technology for discovery of novel cell surface markers that can be used to identify both self-renewing and the most highly migratory MB cells. Methods: Limiting dilutions of high vs low self-renewing MB sub-clones were xenografted into the right cerebral cortex of NOD SCID mice to characterize morphological, phenotypic and survival differences between samples. Similar experiments will be conducted with CD271+ and CD271- cells. MB tumorspheres will be subjected to fluorescent activated cell sorting (FACS), and both CD271+ and CD271- cells will be transplanted into NOD SCID mice. In addition, we are screening high self-renewing vs low self-renewing MB subclones as well as stationary vs migrating cells using a 242 cell surface marker screening panel. Cell surface markers exhibiting differential expression between paired samples will then be further validated and functionally characterized. Results: We have observed differences in survival, clinical presentation and phenotype between high vs low self-renewing MB cells in vivo. Specifically, lower self-renewing MB cells are exhibiting decreased survival, suggesting a negative correlation between stem cell properties in vitro and tumorigenic capacity in vivo. Initial high throughput flow cytometry analysis has revealed interesting novel cell surface marker targets for further study. Conclusions: Our results will enable us to delineate a cell surface fingerprint for MB cells that exhibit stem cell properties and are highly migratory. Identification of these cells will provide the necessary foundation for future drug discovery platforms that will enable selective targeting of both tumor propagating and highly migratory cells with the ultimate goal of improving long-term outcome.
Funding: Canada Research Chairs Program, MHRC. email@example.com 37
Neuroglial proliferative and migratory suppression following paraventricular hemorrhage in the neonate rat - role of transcription factors. Authors: Dmitri KrassioukovAC, Xiaoyan MaoB, Dr. Marc R. Del BigioABC ADepartment of Human Anatomy and Cell Sciences, BDepartment of Pathology, CFaculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada. Rationale: Hemorrhage is a common clinical occurrence in premature infants due to vascular immaturity in periventricular germinal zones. Blood suppresses proliferation and migration of neuroglial precursors in the ventricular/subventricular zone (VZ/SVZ) within 12 hours of hemorrhage. This brief time suggests involvement of a rapid regulatory element like transcription factors (TF). Microarrays allow simultaneous analysis of TF interaction with hundreds of specific DNA-binding elements in the promoter regions of genes. We hypothesize that TF regulatory changes are the cellular mechanisms directly responsible for the rapid cell cycle suppression leading to proliferative and migratory arrest. Methods: Paraventricular hemorrhage was induced in 18 Sprague-Dawley rat pups (<24hr age) via stereotactic bolus of 0.5cc autologous tail vein blood; additionally 9 controls and 9 shams. Injections targeted the VZ/SVZ. Hematomas were confirmed with HASTE and RARE sequences in a Bruker Biospec 7TMRIspectrometer. Animals were humanely sacrificed at 3, 6 and 12 hours post hemorrhage (with time matched controls and shams). Affected hemisphere was dissected and the nuclear protein fraction was isolated. This fraction was incubated with labeled DNA binding oligonucleotides that recognize the formed protein/nuclear DNA complexes. The complexes were separated from the free probes, extracted, and hybridized to the Protein/DNA Microarray. A Bio-Rad GS-700 Imaging Densitometer was used to analyze the microarray spot density. Intact and sham control values were compared to blood injected tissue at the three time points. Results: TF binding changed in four distinct temporal patterns (highest change TFs shown). 1) Progressive increase: WTI(1), E12/E47, PPUR1, PYR, WTI(2), PAX1, HFH-1(1). 2) Progressive decrease: NF1(1), EGR1, GATA-3, c-Rel, E47, Antioxident RE, AP-3 3) Transitory increase: MTF, HFH-8, PU.1, TFE-3L, NCAM BP, NF-4FA, Thy-1BP, LSF, PAX-4, HNF-1A. 4) Transitory decrease: Ahr/Amt, ISRE1, MSP-1, HNF-4/COUP-TF, Surf-2(2) Conclusions: Transcription factor regulation offers one novel explanation for the rapid suppression of neuronal precursor proliferation and migration as a result of hemorrhage in the ventricular/subventricular zones of the developing cerebral cortex, the end result of which may be responsible for numerous developmental and cognitive disorders observed in children and adults.
Contact: firstname.lastname@example.org 38
Levels of Evidence in Pediatrics: A Comparison of Top Medical Journals and General Pediatric Journals Dustin Jacobsona, Kunal Bhanota, Blake Yarascavitchb, Jennifer Chubackb, Ehud Rosenbloomc and Mohit Bhandarid aMichael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada, bDepartment of Surgery, McMaster University, Hamilton, Ontario, Canada, cDepartment of Pediatrics, McMaster University, Hamilton, Ontario, Canada and dDepartment of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada. Rationale: Evidence-based medicine and levels of evidence (LOE) have become important pillars for all facets of medicine. Ideally, clinicians should focus on the resources that provide the highest LOE given the large number of publications in the field. Objective: To understand the current state of evidence within the field of pediatrics, a clear characterization of level of evidence from major sources of pediatric literature is needed. Methods: Clinical pediatric literature, published in the HICJ (NEJM, JAMA, & The Lancet) and the highest impact GPJ (Pediatrics, Journal of Pediatrics, & Archives of Pediatrics & Adolescent Medicine), between April 2011 and March 2012 inclusive, was assessed by two independent reviewers. Excluded articles included basic science or cadaver studies, case reports, review articles and expert opinions. Articles were evaluated based on journal, date of publication, subspecialty within pediatrics, number of authors, geographic region of corresponding author, number of centers, number of subjects/trials, minimum age of entry of subjects, average age of entry of subjects, study subtype and LOE. In addition, eligible level I RCTs were appraised using the CONSORT guidelines. Results: Six thousand five hundred and eleven articles were screened, of which eight hundred and four papers met inclusion criteria. On average, LOE of papers within The Lancet were significantly higher than all GPJ (p<0.05). The Lancet had significantly higher proportions of level I evidence, and significantly lower proportions of level IV evidence compared to all GPJ (p<0.05). NEJM had significantly higher LOE compared to Journal of Pediatrics and Pediatrics (p<0.05). The Lancet showed higher proportions of high LOE (level I & II) studies compared to all other journals (p<0.05). Additionally, average CONSORT scores were significantly higher in the grouped HICJ compared to the GPJ (15.2 vs. 13.6, respectively, p<0.001). Reliability in assessing LOE and CONSORT was excellent between reviewers with kappa scores of 0.877 and 0.894 respectively. Conclusions: LOE and quality of RCTs within the pediatric field is greatest within the HICJ, with The Lancet publishing higher LOE than all GPJ. Therefore, in addition to the GPJ, medical professionals should readily incorporate HICJ into regular readings.
Medical studentsâ€™ attitudes and knowledge about harm reduction and access to health care for people who misuse substances Emily Kendell (BSc, MPH) Memorial University of Newfoundland, 3rd year medical student Rationale: Individuals who misuse substances are at increased risk of poor health outcomes and face barriers when accessing the health care system. Harm reduction strategies are one tool to help improve health outcomes and access to health care for this population. As front line service providers for individuals who misuse substances, physicians should be knowledgeable about harm reduction strategies in order to provide the best possible care. Medical school curriculum plays an integral part in gaining this knowledge and forming attitudes on harm reduction and access to health care for people who misuse substances. Objective: This study aimed to investigate the knowledge and attitudes of first and second year medical students at Memorial University about harm reduction and access to health care for people who misuse substances. Methods: A cross-sectional survey of pre-clerkship medical students (n=129) was conducted at Memorial University. Students completed a 23-item online questionnaire about their attitudes on access to health care for people who misuse substances, knowledge about locally available harm reduction services, and attitudes about the use of harm reduction strategies. Results: There were a total of 83 respondents for a response rate of 64%. Most students knew about locally available harm reduction services and think harm reduction strategies are beneficial. Almost all (95%) agreed that people who misuse substances experience discrimination in the health care system but were divided (43% agreeing) when asked if this population had equitable access to health care. Overall, few students (26%) had previous experience with harm reduction services, and the majority (82%) would like to see more preclerkship teaching about harm reduction in the curriculum. Conclusion: Pre-clerkship medical students at Memorial University have a general knowledge about local harm reduction services; they have a positive attitude towards harm reduction strategies but they are not certain about their attitudes on barriers to health for people who misuse substances. This study suggests that students want more classroom teaching and exposure to harm reduction strategies. This may help promote positive attitudes toward harm reduction services and help students understand the barriers to accessing health care for individuals who misuse substances
Funding: Summer Undergraduate Research Award, Faculty of Medicine, Memorial University. email@example.com 40
Evaluating the Use and Diagnostic Yield of CT Pulmonary Angiography to Exclude Acute Pulmonary Embolism Hamed Basseri a, Andreu F Costa ab, Adnan M Sheikh ab, Ian Stiell acd and Carole J Dennie ab a Faculty of Medicine, University of Ottawa, Ottawa, ON. b Department of Medical Imaging, The Ottawa Hospital, Ottawa, ON. c Department of Emergency Medicine, The Ottawa Hospital, Ottawa, ON. d The Ottawa Hospital Research Institute, Ottawa, ON. Rationale: In most clinical scenarios, Computed Tomography Pulmonary Angiography (CTPA) is the first-line imaging test to exclude pulmonary embolism (PE). However, recent studies have shown increased CTPA ordering rates with a concomitant decrease in number of positive tests, raising concerns about inappropriate CTPA use to exclude PE. Objectives: We aimed to evaluate the yield of CTPA at our tertiary care, academic hospital over a two-year period and assess for any differences in positivity among the following subgroups: 1) emergency patients (ED), inpatients (INPT) and intensive care unit inpatients (ICU); 2) daytime and on-call studies; 3) one year before and after institution of an Emergency Radiology division; 4) interpreting thoracic and non-thoracic radiologists; and 5) individual emergency physicians. Methods: We retrospectively reviewed all CTPA studies performed between April 2008 and March 2010 at our tertiary care hospital. Patients with a history of PE and indeterminate studies were excluded. The diagnosis of PE was based on the radiology report. D-dimer values obtained within 24 hours prior to CTPA were recorded. Results Of 4757 CTPA studies reviewed, 3571 satisfied the inclusion criteria. The fraction of positive studies was 252/1677 (15.0%) ED, 255/1548 (16.5%) INPT, and 62/346 (17.9%) ICU. There was no statistically significant difference in positivity rates between patient groups, daytime vs. on-call studies, before vs. after the institution of an Emergency Radiology division, and thoracic vs. non-thoracic interpreting radiologists (p > 0.05). For ED patients who underwent both CTPA and D-dimer testing, the Ddimer sensitivity was 97.9% (95% CI, 94.0 – 99.6) and the negative and positive predictive values (NPV and PPV) were 98.4% (95% CI, 95.3 – 99.7) and 19.0% (95% CI, 16.2 – 22.1) respectively. The mean emergency physician positivity rate was 15.4% (σ = 8.5%, range, 0 – 38.5%). Conclusions: In contrast to recent studies, our CTPA yield among ED patients was quite high, but varied considerably among individual emergency physicians. While the reasons for such differences require further investigation, our results reinforce the importance of strong clinical assessment in the work-up of suspected PE.
Funding: University of Ottawa - Faculty of Medicine Summer Studentship Program Corresponding Author: Hamed Basseri, firstname.lastname@example.org 41
Hepatocellular carcinoma and treatment with sorafenib: A retrospective study of patients referred to a provincial cancer centre from 2003-2012. Jennifer L LeMessuriera, Melanie D Seala aDivision of Oncology, Faculty of Medicine, Memorial University of Newfoundland, St. John’s, Newfoundland and Labrador, Canada Rationale: Hepatocellular carcinoma (HCC) carries a poor prognosis and historically systemic treatment options have been limited in its advanced stages. Certain patients have been eligible for systemic therapy with the oral multikinase inhibitor sorafenib since its approval in Canada. Objective: To describe the characteristics and survival outcomes of patients presenting to a provincial cancer centre with a diagnosis of HCC and the cohort of those treated with sorafenib. Methods: We conducted a retrospective chart review of adult patients assessed by medical oncology at our cancer centre with a diagnosis of HCC between 2003-2012. We collected information concerning demographics, risk factors, clinical profile, staging, treatment, and outcomes. Descriptive and frequency statistics were used to describe the data. Survival was determined by Kaplan-Meier analysis. Institutional ethics approval was obtained prior to commencing the study. Results: A total of 82 patients met our inclusion criteria. A cohort of 30 patients (36.6%) received sorafenib. The median survival time from first assessment by medical oncology was 3.5 months (95% C.I. 1.7 – 5.4) in all patients and 7.0 months (95% C.I. 3.8 – 10.3) in the sorafenib cohort. Most patients were diagnosed by radiological method (53.7%) with a clinical stage ≥ III (73.3%) and Eastern Cooperative Oncology Group (ECOG) score ≤ 2 (65.0%). In the sorafenib cohort, most patients were diagnosed by pathological method (53.3%) with a clinical stage ≥ III (75.0%) and ECOG ≤ 2 (100.0%). Overall, patients had Child-Pugh Class A (47.5%), B (35.0%), or C (17.5%) liver disease. In the sorafenib cohort, patients had Child-Pugh Class A (80.0%) or B (20.0%) liver disease. Cirrhosis was documented in 59.8% of all patients and 70.0% of the sorafenib cohort. Treatment regimens involved localized therapy (11.0%), systemic therapy (37.8%) or both (7.3%) in all patients and systemic therapy (83.3%) or both (16.7%) in the sorafenib cohort. Conclusion: Most patients presenting to our centre with HCC had advanced disease and a poor prognosis. Many also had impaired hepatic reserve and did not receive active treatment. The cohort of patients treated with sorafenib had better performance scores, hepatic reserve, and overall survival than the entire population diagnosed with HCC.
Funding: Mach-Gaensslen Foundation of Canada email@example.com 42
Evaluation of a novel strategy of Consultation in the Hematology Ambulatory Setting Joanna Slusar1, Stephen Couban1, Sudeep Shivakumar1 1Department of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada. Rationale: In 2010, 444 letters were written by a hematologist at Capital District Health Authority in Halifax, NS. These letters, written in response to referrals from physicians, suggested possible causes of patient’s referring issue and provided a recommended course of action for follow-up. These patients were then managed by their referring practitioner based on the recommendations in the letter instead of being assessed by the specialist at the hospital outpatient clinic. The objectives of this study were to 1) characterize the cohort of patients for whom written recommendations were written and 2) assess whether the written recommendations were a helpful and satisfactory alternative for the referring practitioner. Methods: All patients who received written recommendations in 2010 as a substitution for outpatient assessment were included in the study with no exclusion criteria applied. The followup time period was 1 year after the date of written recommendations. All physicians who were the recipient of recommendation letters were sent a satisfaction survey comprised of 7 “yes or no” questions. Results: The most common reasons for referral were mild leucopenia (17%), thrombocytopenia (21%), mild anemia (22%), elevated ferritin (12%) and suspected hemochromatosis (7%). 22% of all patients for whom written recommendations were written did not require follow-up and 10% of all patient’s abnormalities had completely resolved at the time of assessment by the hematologist. After 1 year follow-up it was found that 13% of patient's abnormality had resolved and 45% of patient's abnormalities remained the stable. There was a single hematologicalrelated death within the one year follow-up in which the patient refused further medical investigations and intervention. 1% of patients had their hematological abnormality worsen. Of the 203 referring practitioners that responded to the satisfaction survey, 95% were pleased to receive the recommendations and 90% would be satisfied with written recommendations in the future. Conclusion: These results suggest that written recommendations may be a safe and satisfactory alternative to outpatient assessment.
Funding: Cancer Care Nova Scotia firstname.lastname@example.org 43
SESSION 3 Poster Discussion Brodie Centre Mezzanine 14:15 â€“ 15:25 p.m. Wednesday, June 5th, 2013
Hospitalization with Delirium in Older Adults from Standard Dose Histamine2-Receptor Antagonists: A Population-Based Study Davy Tawadrous BHSc1,2, Stephanie Dixon PhD1,2,3,4, Salimah Z. Shariff PhD1,4, Jamie Fleet BHSc2, Sonja Gandhi BSc1,2,3, Arsh K. Jain MD, MSc1,2,3, Matthew A. Weir MD, MSc1,2,3, Tara Gomes MHSc4,5,6, Amit X. Garg MD, PhD1,2,3,4 1 2 3 4 5 6
Schulich School of Medicine, Western University, London, Canada Division of Nephrology, Western University, London, Ontario, Canada Department of Epidemiology and Biostatistics, Western University, London, Ontario, Canada Institute for Clinical Evaluative Sciences, Ontario, Canada Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada Keenan Research Centre, Li Ka Shing Knowledge Institute, Toronto, Ontario, Canada
Acknowledgements: We thank Brogan Inc, Ottawa, for use of its Drug Product and Therapeutic Class Database, Gamma Dynacare for use of the outpatient laboratory database and the team at London Health Sciences Centre, St. Josephâ€™s Health Care, and the Thames Valley Hospitals for providing access to the Cerner laboratory database. Support: Mr. Tawadrous was supported by a Medical Student Schulich Research Training Program award from the Schulich School of Medicine and Dentistry. Dr. Garg was supported by a Clinician Scientist Award from the Canadian Institutes of Health Research. Financial Disclosure: The authors declare that they have no relevant financial interests. The Institute for Clinical Evaluative Sciences (ICES) is a non-profit research corporation funded by an annual grant from the Ontario Ministry of Health and Long-Term Care (MOHLTC). The research was conducted at the ICES@Western facility, which receives financial support from the Academic Medical Organization of Southwestern Ontario, the Schulich School of Medicine and Dentistry at Western University and the Lawson Health Research Institute. The opinions, results and conclusions are those of the authors and are independent from the funding sources. No endorsement by ICES or the Ontario MOHLTC is intended or should be inferred. ABSTRACT Importance: Standard doses of histamine2-receptor antagonists (H2RAs) may induce delirium in older adults, especially in those with reduced elimination caused by chronic kidney disease (CKD). Objectives: To characterize 30-day risk of delirium and mortality in older adults initiated on an oral H2RA either at a standard dose (ranitidine [Zantac] 300 mg/day or famotidine [Pepcid] 40 mg/day) or low dose in routine outpatient care, and determine if risk is modified by the presence of CKD. Design: Population-based cohort study using seven linked healthcare databases. Setting: Ontario, Canada. Participants: Older adults starting a new H2RA either at a standard dose or low dose between 2002 and 2011. Outcomes: Primary outcome was 30-day evidence of hospitalization with an urgent head computed tomography (CT) scan (proxy for acute delirium). Secondary outcome was 30-day all-cause mortality Results: Ninety percent (90%) of older adults received a standard H2RA dose. No significant difference in the 23 baseline patient characteristics measured in each of standard and low H2RA dose groups. Standard vs. low H2RA dose was associated with a higher risk of hospitalization with head CT scan (1,895/193,135 [0.98%] vs.141/19,115 [0.74%], absolute risk difference 0.24% [95% CI 0.11% to 0.36%], number needed to harm 417, relative risk 1.33 [95% CI 1.12 to 1.58]). Risk was not modified by the presence of CKD (interaction P value = 0.71) and remained evident in patients with preserved kidney function. Standard vs. low H2RA dose was associated with a higher risk of mortality (1.07% vs.0.74%; absolute risk difference 0.34% [95% CI 0.20% to 0.46%], number needed to harm 295, relative risk 1.46 [95% CI 1.23 to 1.73]). Conclusions: Compared to a lower dose, initiation of a standard H2RA dose in older adults is associated with a small absolute 30-day increase in likelihood of delirium and death even in the absence of CKD. email@example.com
Trends in Revision Rates and Reasons For Revision â€“ Information from a Regional Health Authority Joint Replacement Registry Jas Singh, David Hedden, Lynda Loucks, Eric Bohm Department of Surgery, Section of Orthopaedic Surgery, University of Manitoba, Winnipeg, Manitoba. Rationale: Joint replacement registries are playing an increasingly important role worldwide in improving health care delivery. In 2004, we implemented a regional hip and knee replacement registry that incorporated direct feedback to surgeons and sites on the quality of care that they provided. The purpose of this study was to examine trends in three important quality measures: revision workload, early revision rates and the reasons for revision. Methods: Examination of the rates of early revision (within two years), revision workload as a percentage of overall volume, and frequencies of reasons for revision over the period from 2004 to 2009 was carried out. Reasons for revision were coded using the Canadian Joint Replacement Registry classification. Results: From 2004-2009, hip revisions accounted for 17.0% of total hip arthroplasty volume; this started at 24% in 2004 and decreased to 15% in 2009. Knee revisions accounted for 9.6% of total knee arthroplasty volume; this started at 14.5% in 2004 and decreased to 10.5% in 2009. Two-year revision rates for primary hip replacements were, 3.8% (2004), 2.6% (2005), 2.2% (2006), 2.2% (2007), 2.0% (2008) and 1.8% (2009). Two-year revision rates for primary knee replacements were, 1.7% (2004), 2.5% (2005), 2.3% (2006), 1.9% (2007), 1.8% (2008) and 1.9% (2009). The top four reasons for early hip revision were: (1) Infection (33%), (2) Aseptic Loosening (25%), (3) Instability (24%) and (4) Periprosthetic Fracture (15%). The top four reasons for early knee revision were: (1) Infection (40%), (2) Instability (28%), (3) Stiffness (12%), and (4) Aseptic Loosening (6%). Conclusions: Although the absolute number of revision procedures performed per year has remained relatively stable, the fraction of the entire arthroplasty caseload that comprise revision procedures has seen a noteworthy reduction. Two-year revision rates for both hips and knees have seen a statistically significant reduction, lending considerable weight to the assertion that joint replacement registries are providing surgeons with the feedback they need to optimize patient outcomes. Finally, infection remains the number one reason for revision and further efforts to reduce revision workload and rates should be directed at addressing preoperative antibiotic prophylaxis and compliance with infection control protocols.
Intramedullary spinal cord cavernomas: a systematic review. Jetan Badhiwalaa, Saleh A. Almenawerb, Naresh Murtyb, and Kesava Reddyb aMichael G. DeGroote School of Medicine, bDivision of Neurosurgery/Department of Surgery, McMaster University. Hamilton, Canada. Rationale: Intramedullary spinal cord cavernomas (ISCCs) have traditionally been the subject of exceedingly rare case reports. Only in recent decades have sizeable series been published, likely owing to the advent/widespread availability of MRI. Hence, there is currently limited evidence regarding ISCCs. Objectives: To consolidate contemporary clinical data regarding ISCCs, and moreover, to elucidate relevant prognostic factors. Methods: We searched MEDLINE, EMBASE, CINAHL, Google Scholar, and The Cochrane Library for series reporting ≥3 patients with ISCCs. Pooled data from eligible reports were used to establish the epidemiology, clinical features, natural history, and treatment outcomes of ISCCs. For the subcohort with individual patient data, we performed logistic regression analyses to identify predictors of favorable outcome (event=’improved neurological function’). Age (≤50/>50 yrs.), gender (male/female), spinal level (cervical/thoracic/lumbar), size (≤10/>10 mm), clinical course (acute/progressive), symptoms (motor/sensory/pain/bladder-bowel), intracerebral cavernomas (yes/no), family history (positive/negative), management (resection/observation), pre-surgery symptom duration (≤3/>3 mos.), and extent of resection (gross-total/subtotal) were expressed categorically and evaluated as predictors. Results: Thirty-nine series reporting 608 patients met eligibility criteria. Mean age was 39.1 years (2–80 yrs.) and male/female ratio 315:293. Spinal level of cavernoma was cervical (N=230/37.8%); cervicothoracic (N=14/2.3%); thoracic (N=336/55.3%); thoracolumbar (N=4/0.7%); lumbar (N=13/2.1%); or conus medullaris (N=11/1.8%). Average cavernoma size was 9.0 mm. In 274 cases (55.0%), clinical course was progressive; 224 (45.0%) presented acutely. Symptoms were motor (N=330/61.7%); sensory (N=309/57.8%); pain (N=177/33.1%); bladder-bowel (N=128/23.9%); respiratory distress (N=3/0.6%); and asymptomatic (N=5/0.9%). Intracerebral cavernomas occurred in 14.2% of patients and positive family history in 7.2%. The overall annual hemorrhage rate was 2.1%. Most patients (N=556/91.6%) underwent resection; 51.4% experienced subsequent clinical improvement. Of 51 conservatively-treated patients, 35.0% improved. Age, gender, spinal level, size, symptoms, intracerebral cavernomas, and family history were not important prognostic factors. Acute clinical course correlated with favorable prognosis (OR=1.70, 95%CI 1.07–2.71, p=0.03). Resection resulted in better outcomes than conservative treatment (OR=2.12, 95%CI 1.03–4.37, p=0.04). Also, earlier operation (≤3 mos.) (OR=2.11, 95%CI 1.31–3.41, p=0.002) and gross-total resection (OR=3.31, 95%CI 1.12–9.79, p=0.03) were associated with higher rates of neurological improvement postoperatively. Conclusions: Our findings support early resection, with the goal of complete removal, for symptomatic ISCCs.
Efficacy and safety of different bridging regimens of parenteral anticoagulation after mechanical valve replacement. Joseph G. Mathewab, Arif Yusufb, Jessica Vincentb, John Eikelboomb, Olga Shestakovskab, Alex Spyropolousc, Alex Pateld, Sam Schulmand, Menaka Paid, Richard Whitlockb aMichael G. DeGroote School of Medicine, McMaster University, Hamilton, Canada bPopulation Health Research Institute, McMaster University, Hamilton, Canada cUniversity of Rochester Medical Center, Rochester, United States of America dMcMaster University, Hamilton Health Sciences, Hamilton, Canada Rationale: Limited evidence exists to guide the use of parenteral anticoagulation in the early postoperative period following mechanical valve replacement (MVR). The purpose of this study was to determine the practice patterns of anticoagulant management in patients undergoing MVR and to compare the 30 day rates of thrombotic and bleeding complications for patients receiving therapeutic vs. non-therapeutic bridging regimens. Methods: We conducted a retrospective chart review of all patients undergoing MVR at five Canadian cardiac surgery centers between January 1, 2003 and December 31, 2010. The primary efficacy outcome was thromboembolism (stroke, transient ischemic attack, systemic embolism or valve thrombosis). The primary safety outcome was major bleeding. Secondary outcomes included venous thromboembolism and death. Treatment effects were assessed using a matched propensity score analysis. Results: We included 1777 patients (mean age 58 years, 40% female) of whom 939 (56%) underwent isolated aortic valve replacement, 578 (34%) isolated mitral valve replacement, and 171 (9%) combined aortic and mitral valve replacement. 944 patients (53%) received therapeutic bridging and 749 patients (42%) received non-therapeutic bridging. Twenty-three patients (2.4%) who received therapeutic bridging versus thirteen patients (1.7%) who received non-therapeutic bridging experienced the primary efficacy outcome of arterial thromboembolism (odds ratio [OR] 1.53; 95% confidence interval [CI], 0.65 to 3.59, P=0.33). Fifty-two patients (5.5%) in the therapeutic dosing group vs. twelve patients (1.6%) in the non-therapeutic dosing group experienced the primary safety outcome of major bleeding (OR 4.61; 95% CI, 2.15 to 9.87; P <0.0001). Conclusion: In the early postoperative period following MVR, therapeutic bridging anticoagulation was associated with a similar risk of thromboembolic complications and a significantly increased risk of major bleeding compared to non-therapeutic bridging anticoagulation. These results suggest that therapeutic anticoagulation should not be routinely used in patients following mechanical heart valve replacement.
Funding: McMaster Surgical Associates AFP Grant firstname.lastname@example.org 48
COPD Care in the Acute Care Setting - Clinician's and Patient's Perspectives Mariam Rassem, Darcy Marciniuk, MD, FRCPC, FCCP, Mark Fenton, MD, FRCPC, FCCP Respirology, Chronic Disease Management, Inter-Disciplinary Clinical Care. University of Saskatchewan. Saskatoon, Canada. Rationale: Our Project aims to assess the appropriateness of care COPD patients receive in the Saskatoon Health Region (SHR) by comparing the care they receive at two various sites (Sites A and B) with that outlined in evidence-based clinical practice guidelines. COPD exacerbations are the most common reason for patients to be admitted to hospital for a chronic medical condition. Moreover, the incidence of COPD is projected to further increase for the next 35-40 years. The Object of this Project is to identify differences in care between the two Sites A and B, not necessarily to identify the reasons for any discrepancy. Methods: The research carried out in this project was two-fold: chart reviews of patients with a primary diagnosis of COPD from Sites A and B as well as interviews with patients discharged from hospital. Patients consented to being interviewed to assess their contentment with the care they received and to garner insight into potential opportunities for enhanced care. Results: In comparing the two sites, some variables were found to be similar, while others were significantly different. For instance, the patient average length of stay at Site A was found to be 9 days, while Site Bâ€™s was 15 days. The interviews with patients revealed that most patients participating in the COPD program are pleased with it and enjoy the supportive, social atmosphere it offers. Many report noticing an improvement in their quality of life and energy levels. Non-program patients report they are unable to participate in the program because of other health concerns, a busy schedule, or because they already participate in similar programs. Other findings will be presented. Conclusion: Gaps/barriers have been identified in the care of COPD patients in the SHR. If others are discovered, these could be remedied to improve outcomes, reduce hospitalization, and prevent readmissions with the goal of enhancing the patientâ€™s health status and disease management by the inter-professional healthcare team.
Funding: SHR, RQHR, University of Saskatchewan email@example.com 49
How do we treat acute immune thrombocytopoenia (ITP) in the Maritime provinces? Jennie Lee1, Bruce Crooks1,2 1 Dalhousie University, Halifax, NS, 2IWK Health Center, Halifax, NS Background Immune thrombocytopoenia (ITP) is the commonest bleeding disorder of childhood and is characterized by an isolated low platelet count. ITP is usually self-limiting (80% spontaneously resolve within a year). Many patients are treated to avoid clinically significant, yet rare, bleeding. Published guidelines have differed in recommendations. This study aimed to explore approaches in managing acute ITP at the IWK Health Centre and across the Maritimes. Methods A literature review, retrospective chart review of ITP patients followed at the IWK since 1 January 1990, and an online survey of paediatriciansâ€™ practices were conducted. Results Published guidelines are converging and encourage paediatricians to treat based on symptoms not absolute platelet counts. Chart review showed that 99/144 patients received at least one course of treatment â€“ 60/99 with IVIg and 37/99 with corticosteroids The decision to treat 66/99 was on platelet count alone. Bone marrow examinations, recommended in an atypical presentation or prolonged course of disease, were performed in 54 patients. IWK paediatricians relied on clinical experience in 135 cases and consultation with colleagues in 36 cases. 24 Maritime paediatricians who responded to our online questionnaire manage ITP. 17completed the survey.19/24 were uncertain of recommended diagnostic platelet counts for ITP. 2/24 reported using published resources to complete the survey. 13/21 paediatricians reported they would use published guidelines to guide management in provided case scenarios and 17/21 would consult colleagues. Conclusion Actual management of acute ITP differs from published guidelines: patients are treated more for platelet counts and may be over-investigated and over-treated. Lack of adequate documentation may bias results. Maritime paediatricians prefer managing patients collaboratively, but further education is needed. A prospective survey would explore this further.
Distinct Cell Signaling Mechanisms Drive TNFα and IFNγ-Induced Transcriptional Downregulation of Aquaporin 3 RNA Expression Michael A. Peplowski, Andrew J. Vegso, Wallace K. MacNaughton Inflammation Research Network, Department of Physiology & Pharmacology, Faculty of Medicine, University of Calgary, Calgary, AB. Aims: Altered absorption and secretion of water, resulting in diarrhea, is a key characteristic of inflammatory bowel diseases (IBD). Although aquaporins (AQP) are known to be involved in water movement, the role of AQP3 in the barrier dysfunction that characterizes IBD remains unknown. We hypothesized that AQP3 transcription was inhibited in intestinal inflammation by the cytokines tumour necrosis factor (TNF) α and interferon (IFN) γ. Methods: 1. C57Bl/6 mice were administered 2.5% dextran sodium sulfate (DSS) in drinking water for up to 7 days to induce colonic inflammation. AQP3 protein expression was assessed using western blot of mucosal scrapings and immunofluorescence of fixed tissue. 2. The human adenocarcinoma cell line HT29 was used for in vitro treatments with either human recombinant TNFα (25 ng/mL) or human recombinant IFNγ (500 U/mL). AQP3 pre-mRNA and mRNA expression was assessed by real-time RT-PCR. Inhibitor studies to abrogate the cytokineinduced decrease in AQP3 mRNA expression were performed using a 1hr pre-treatment with inhibitors prior to the addition of cytokine. Results: 1. AQP3 protein expression was downregulated early in colonic inflammation at 3 days post-commencement of DSS. 2. Similarly, HT29 cells treated with TNFα or IFNγ resulted in an early decrease in AQP3 pre-mRNA expression at 2 hr, which was followed by decreased mRNA expression at 6-12 hr. The IFNγ-induced decrease in AQP3 mRNA expression at 12 hr was reversed using a broad-spectrum JAK inhibitor (JAK Inhibitor I, 10 µM), but not a JAK2 specific inhibitor (JAK2 Inhibitor II, 10 µM). In contrast, the TNFα-induced decrease in AQP3 mRNA expression at 12 hr was not reversed by inhibitors of the PI3K, AKT, NF-κB, ERK/MAPK and p38 MAPK pathways (LY294002, 10 µM; Triciribine, 1 µM; BAY11-7082, 30 µM; U0126, 10 µM and SB203580, 10 µM respectively), even though all of the above pathways were activated by TNFα and significantly inhibited by their respective inhibitors. Conclusions: The data suggest that alterations in AQP3 expression represent early events that occur in colonic inflammation. In vitro, both TNFα and IFNγ are independently capable of decreasing AQP3 mRNA transcription through distinct mechanisms.
Funding: AIHS, CIHR, CCFC. firstname.lastname@example.org
Uncovering the Role of Topoisomerase II-Beta Binding Protein 1 in DNA Replication Stress Response Mark Assmus, Charles Leung, Inbal Mermershtain and Mark Glover Department of Biochemistry, University of Alberta. Edmonton, Alberta, Canada. Rationale: Every day our DNA encounters unavoidable genotoxic attacks which can progress to single and double-strand breaks in DNA. These DNA lesions cause the replication fork to stall, leading to genomic instability, one of the primary hallmarks in the development and progression of cancer. Since the importance of maintaining genomic stability has been shown in hereditary cancers it is key to understand these repair mechanisms for the advancement of future cancer treatments. TopBP1 represents one of the critical mediator proteins in the DNA damage response to replication stress in mammalian cells. Objectives: Investigate how TopBP1 BRCT domains facilitate two protein-protein interactions with the Rad9-Hus1-Rad1(911) complex and mediator of DNA damage checkpoint protein 1(MDC1). Methods: We used standard cloning and sequencing procedures as well as a general protein purification pipeline to produce numerous protein constructs of TopBP1 and binding targets. These purified proteins were used in structural and biochemical experiments involving x-ray crystallography, fluorescence polarization(FP), GST pull downs and western blotting to examine the mechanisms of the TopBP1 interactions. Results: I over-expressed and purified the 911 complex, TopBP1 290, GST-TopBP1 290, GST protein, GST fusion proteins of TopBP1 BRCT 4/5 and TopBP1 BRCT 5, as well as TopBP1 BRCT 5 alone. The GST pull downs show the 911 complex is efficiently co-precipitated with GST-TopBP1 290 when it was pre-phosphorylated in vitro by CK2Îą. The results of the FP assays indicate that it is the BRCT 5 binding pocket that is responsible for interacting with MDC1 and that dimerization induced by GST allows for tighter binding. Additionally, decreases in binding affinity were associated with mutation of key conserved residues in the binding pocket. FP confirmed that the phosphorylation of MDC1 is essential for TopBP1 BRCT 4/5 recognition. Conclusions: The GST pull down results will allow us to move towards large-scale purification of the 911-TopBP1 290 complex for SAXS and x-ray crystallography. Taken together, the FP results further support the unique dimerization-based binding mechanism suggested by the crystal structure of MDC1/TopBP1 BRCT 4/5 binding. These investigations contribute significantly to understanding the role of TopBP1 in regulating the replication stress response.
Funding: AIHS. email@example.com 52
Development of a Microbiome Approach to Sepsis and Application of Novel Methods to Whole Blood Authors Monica M. P. Faria2,4, John M. Conly1-4, and Michael G. Surette2,4,5 Affiliations Departments of Medicine1, Microbiology, Immunology & Infectious Diseases2, Pathology & Laboratory Medicine3, Snyder Institute for Chronic Diseases4, Faculty of Medicine, University of Calgary, Calgary, Canada; Farncombe Family Digestive Health Research Institute, Departments of Medicine and Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada5. Background The application of molecular profiling methods to a wide variety of infections suggests that polymicrobial infections are much more common than suggested by standard clinical culture. Our goal was to develop methods, using a microbiome approach, to improve culture and molecular diagnostics for bacterial sepsis. Materials and Methods Culture and DNA extraction protocols were evaluated using synthetic bacterial communities inoculated into whole blood. Disruption of blood cells with a blood cell lysing detergent, with or without hypotonic osmotic shock, was carried out and evaluated for the ability to recover the community. Viable bacterial cells were recovered on solid media. Total DNA was examined by terminal-restriction fragment length polymorphism (TRFLP) profiling. Efficiencies of recovery and limits of detection were determined. The optimized methodology was applied to clinical samples collected from consented patients in both the ICU and ED from 2 Calgary hospitals. Cultured organisms were identified by 16S rRNA gene sequencing. Molecular profiling was carried out using TRFLP and paired-end Illumina sequencing. Results Treatment of synthetic community organisms with a 5% wt/vol detergent added at a 1:1 or 1:5 ratios did not significantly impact their viability. TRFLP analysis indicated that the DNA from these communities could be recovered from whole blood following lysis and removal of host cells. Whole blood samples were analysed from septic patients. In three case studies we identified 2-16 bacterial species in the primary infection samples using direct culture and molecular methods. Conventional diagnostics only reported one organism. Molecular profiling of blood samples from these patients also identified correlating polymicrobial communities. Blood cultures for these samples were either negative (2 of 3 cases) or monomicrobial (1 of 3 cases) thereby underestimating the diversity seen with the TRFLP and Illumina sequencing analysis. These methods have been applied to 88 adult ICU blood samples, 20 primary infection samples, 36 adults ED samples, and 7 pediatric ED samples with analysis ongoing. Conclusions We have successfully developed a novel method to analyse whole blood in order to characterize the microbiome of sepsis infections. Preliminary results indicate that sepsis infections are polymicrobial in nature. Acknowledgments All samples are collected through the Critical Care Epidemiologic and Biologic Tissue Resource.
A novel combined approach using genetics and clinical variables to predict high onclopidogrel platelet reactivity. Nitan Gargab, Jason D. Robertsb, George A. Wellsb, Marino Labinazb, Michel R. Le Mayb, Christopher Gloverb, Michael Froeschlb, Alexander Dickb, Jean-Francois Marquisb, Ruth McPhersonb, Benjamin Hibbertb, Jordan Bernickb, Derek Y. Sob aFaculty of Medicine, University of Ottawa, Ottawa, ON bUniversity of Ottawa Heart Institute, Ottawa, ON Rationale: Inadequate inhibition of platelets in response to clopidogrel—high on-clopidogrel platelet reactivity (HPR) —is associated with major adverse cardiovascular events in patients following percutaneous coronary intervention (PCI). Several clinical variables and genetic polymorphisms influencing clopidogrel biotransformation have been linked to HPR. We aimed to determine the relative association of these variables to HPR and to derive and evaluate a novel combined genetic/demographic approach to identify patients at increased risk for HPR after PCI. Methods: 185 patients who received a 600 mg clopidogrel loading dose and underwent PCI for stable coronary artery disease or non-ST-elevation acute coronary syndrome (ACS) (derivation cohort) were genotyped for genetic variants influencing HPR: CYP2C19*2, CYP2C19*3, CYP2C19*17, and ABCB1 3435 C>T. A multivariate analysis of genetic and clinical variables was used to develop a weighted risk score for predicting HPR, based on the derivation cohort. The risk score was then applied to a validation cohort to evaluate its ability to predict HPR in patients who underwent PCI for ST-elevation ACS. Results: Baseline demographics among patients in the derivation cohort include: mean age 60.1 ± 9.0, mean BMI 28.6 ± 5.6, 94.6% Caucasian, 22.7% with diabetes mellitus (DM), 37.8% with ACS, and 31.4% current smokers. Baseline demographics among 72 patients in the validation cohort include: mean age 57.0 ± 9.2, mean BMI 28.7 ± 5.2, 91.7% Caucasian, 15.3% with DM, and 56.9% current smokers. CYP2C19*2 prevalence was 24.3% and 26.4% in the derivation and validation cohorts, respectively. CYP2C19*2 (p=0.002), DM (p<0.001), age>60 (p=0.015), and BMI>28.1 (p=0.032) were independently associated with HPR and included in the prediction model for the risk score. Use of the risk score provided incremental predictive value for HPR compared to genetics alone. Sensitivity and specificity of the risk score in the validation cohort were 80% and 61.3%, respectively. Conclusions: CYP2C19*2, DM, elderly age, and elevated BMI were independent predictors of HPR. A combined genetics and demographics approach using these variables provides incremental value in predicting platelet response to clopidogrel compared to genetics alone. Validation of this model in larger cohorts may lead to development of future strategies for personalized antiplatelet therapy.
Funding: CIHR firstname.lastname@example.org
Quantitative Evaluation of Two Leading Open-Source Image Registration Tools for Automatic Volumetry of the Corpus Callosum. P Smith, MENG1, D. K. Li, MD2, A. Traboulsee, MD3, and R. Tam, PhD4 MS/MRI Research Group1, Department of Radiology2,4, Department of Neurology3, University of British Columbia Rationale: The emergence of robust neuroimage analysis software enables automatic volumetry of brain structures commonly associated with neurodegenerative disease such as multiple sclerosis (MS). However, it is unclear how much variability can be expected from the choice of tools as their application is not standardized. In our study, we demonstrate the use of two open-source, state-of-the-art image registration tools, namely SyN (Symmetric Normalization) and ART (Automatic Registration Toolbox), in the automatic measurement of the corpus callosum area (CCA) in the mid-sagittal plane (MSP). Objectives: Our goal was to find whether significant differences in volumetry exist between the tools when applied to our task, to the extent that tool selection could impact the outcome of clinical studies. Methods: We randomly selected 100 3-D, T1-weighted axially acquired MR images of patient brains from a recent MS clinical trial. Image format was 256 x 256 x 180 with 0.976 mm x 0.976 mm x 1 mm voxel size and the AC-PC line manually centered in the volume during acquisition. Extra-cranial regions were deleted from the images using BET, and the CC was manually segmented in the MSP using ITKSNAP to provide ground truth. Patient brains were affinely registered to the MNI152 reference using FLIRT followed by non-linear transformations with SyN v1.9 and ART v2.0. The JHU CC label for the MNI152 atlas was then propagated to patient space using the corresponding inverse transformations. Results: The overlap between the automatic and manual segmentations was measured with the Dice coefficient (SyN = 0.764, ART = 0.769). The Wilcoxon test (p = 0.475) showed no significant difference between SyN and ART. The correlation of CCAs between automatic and manual segmentations was measured with Spearman’s rank coefficient (SyN ρ = 0.815 p = 9.41e10-24 vs. ART ρ = 0.507 p = 1.60e10-7), showing that the SyN and manual segmentations were more strongly correlated. Conclusions: SyN and ART perform very similarly for common metrics in ours and past studies; however, there is sufficient difference in the volumetric correlation to ground truth that they cannot be considered equivalent. In order to compare results between clinical studies, standardization of the image analysis pipeline is critical.
A Longitudinal Study of the Relationship of Hopelessness to Excessive Drinking Among University Students Roderick Clarka, Sean Alexanderb, Ivy-lee Kehayesb, Sherry H Stewartab, Mackinnon Seanab a Department of Medicine and bDepartment of Psychology, Dalhouise University Rationale: Research shows that emerging adults (ages 18-25) attending university are at high risk for heavy drinking and alcohol dependence (Dawson et al., 2004). Several co-morbid conditions are thought to increase an individualâ€™s risk of alcohol problems, including depression (Grant et al., 2004), hopelessness (Woicik et al., 2009), and drinking to cope with depression (Grant et al., 2007). It was theorized that drinking to cope with depression would mediate the relationship between hopelessness and alcohol problems Methods: This study was a 3-wave, 12-month longitudinal examination of the relationship between depression, hopelessness and drinking to cope with depression among 302 university student drinkers. Results: Hopelessness indirectly predicted alcohol problems through drinking to cope with depression. These results support the self-medication hypothesis where people who endorse a high level of hopelessness are more likely to develop drinking to cope with depression drinking motives, which in turn leads to future alcohol problems. Conclusions: By understanding the relationship between hopelessness and alcohol problems, we hope to inform targeted alcohol interventions in order to maximize their effectiveness. This is important both for the treatment of individuals who are already experiencing alcohol related problems, and for the identification of individuals who are at high risk of developing these problems.
Funding: Dalhousie University Marvin Burke Studentship in Alcohol and Substance Use. Roderick.Clark@dal.ca 56
Risk factors for falls and fragility fractures in community-dwelling seniors Sacha Song,a Ruby Grewalb and Joy C. MacDermidb a Schulich School of Medicine & Dentistry – Windsor Program, University of Western Ontario, Windsor, Ontario b Division of Orthopedic Surgery, University of Western Ontario, Hand and Upper Limb Center, St Joseph’s Health Care, London, Ontario Objective: To evaluate risk factors for falls and fragility fractures in healthy seniors. Methods: Fifty ambulatory community-dwelling volunteers over age 65 were recruited and the following information was collected: demographics, BMI, bone mineral density (BMD), fracture risk (FRAX), balance, fear of falling (measured with the Modified Falls Efficacy Scale (MFES)), and activity level (RAPA). Results: There were 17 males and 33 females (mean age 72.0 ± 5.5 years), with the majority having a normal BMD and being active. The average MFES score was 9.47 ± 0.97, indicating that overall there was little to no fear of falling. Balance scores did not correlate with FRAX or fear of falling. Activity level did not correlate with FRAX scores, but the active group had less fear of falling. The majority scored below their age specific norms on balance testing. Fear of falling was not significantly different between genders (p = 0.26) but did correlate with FRAX scores (r = -0.34, p = 0.02), indicating that patients with higher risk of fracture were also more afraid of falling. Conclusions: Community-dwelling seniors who had a higher risk of future fractures determined by FRAX were also more afraid of falling. Although our study population consisted of healthy, active participants who overall had good BMD, the majority of them had poor balance compared to age matched norms. Further research is needed to determine how to best assess fall risk and improve balance to prevent fragility fractures in this cohort.
Funding: Schulich Research Opportunities Program (SROP) grant email@example.com
Direct Admissions to the Orthopaedic Ward from the Emergency Department: A Canadian Survey of Attitudes and Trends Authors: Stephen Leea, Jordan Buchkoab, June Zimmera, Kish Lystera, Rob Woodsac,Ted Tufescud, and Jeremy Reeda. aUniversity of Saskatchewan, bDepartment of OrthopaedicsUniversity of Saskatchewan, cDepartment of Emergency Medicine- University of Saskatchewan, d Department of Surgery- University of Manitoba Rationale: To determine the current attitudes and trends regarding direct admissions to orthopaedic wards from both emergency departments and outside facilities. Methods: An online survey was distributed to 872 practicing members of the Canadian Orthopaedic Association, 167 responded. Topics included participant demographics, the effects of direct admission on participants’ current practice, and participants’ perspectives on direct admissions specific to three clinical scenarios provided. Results: There is diversity in policy and practice across the country. 49% of orthopedic surgeons reported trauma patients being directly admitted to the ward under their care without having face-to-face patient contact prior to admission. 50% allowed direct admission within their own facility, whereas 43% allowed direct admission from outside facilities. The three most important factors that influence direct admissions are the presence of 24/7/365 housestaff coverage, the presence of a dedicated trauma team, and population size. There are polarizing views amongst orthopaedic surgeons regarding direct admission. 73% believe it is safe to have direct admission within their own facility, whereas only 61% feel it is safe to have direct admission from outside facilities. 28% consider direct admission unsafe. Conclusions: Both policy and opinion on direct admission are mixed. Of the physicians interviewed, practices are split with approximately half of surgeons allowing direct admissions to the ward. The opinions of orthopaedic surgeons on direct admission are quite divided, with most feeling that it is a safe practice, but 28% considering it unsafe. Surgeons feel safer with direct admission from within their own facilities as opposed to admission from external centers. The Canadian Association of Emergency Physician (CAEP) has stated clearly that it is in the best interest of patients to have the admitting physician assess the patient and write admission orders. Our survey demonstrates that despite CAEP’s suggestion, direct admission to the orthopedic ward occurs frequently, sometimes with, and sometimes without the blessing of the orthopod who has now been tasked with being the most responsible physician. It is the author’s opinion that these practice patterns warrant further interdisciplinary discussion, and possibly a position statement, similar to CAEP, from the Canadian Orthopaedic Association.
Factors Affecting Cancer Patient Willingness to Provide Biological Samples for Pharmacogenomic and Genetic Testing Tenneille T. Looa, Sinead Cuffea, Henrique Hona, Petra Martina, M. Catherine Browna, Shabbir Alibhaib, Natasha Leighla, Celine Mascauxa, Ming Sound Tsaoa, Frances A. Shepherda, Xin Qiua, Wei Xua, and Geoffrey Liua aDepartment of Medical Oncology, Princess Margaret Hospital, University Health Network, Toronto, Ontario; bInternal Medicine, Toronto General Hospital, University Health Network, Toronto, Ontario Rationale: Genetic and pharmacogenomic tests (PGT) have revolutionized medicine by providing the means to predict, diagnose, and monitor various diseases, and by offering individualized treatments to maximize drug efficacy and safety, respectively. However, the practical uptake of these tests is hindered by patient willingness to provide biological samples. By reducing toxicities and suboptimal treatments, and improving response and survival rates, the clinical utility of these tests has been most prominently demonstrated in oncology patients. Cancer patientsâ€™ perspectives on providing additional biospecimens are important in addressing potential knowledge translation barriers. Objectives: To describe the differences in factors affecting patient willingness to provide different types of biospecimens, and to identify barriers affecting the use of these established anti-cancer agents. Methods: 790 English-speaking adult clinic patients from the Princess Margaret Cancer Centre (Toronto, Canada), representing a wide distribution of adult solid and hematological disease sites, were interviewed using a standardized hypothetical questionnaire. Study endpoints included patient preferences and willingness to provide biological samples (blood or biopsy). Univariate and multivariate models were created using SAS 9.3. Results: Patients were 49% female; 77% Caucasian and 23% non-Caucasian; with a median age of 56 years; and 67% had completed high school with median household income evenly trichotomized at $50K and $100K. Despite 33% of the patients being uncomfortable with the level of their knowledge about PGT, 75% agreed that additional tests would be beneficial to their health (75%, p<0.05). Patient willingness to provide new samples was 89% for blood and 54% for biopsy. Caucasians who thought that additional tests would beneficial, that providing new blood tests were not distressing, and who understood genetic testing, were more agreeable to providing new blood samples (adjusted OR 2.60, 2.99, 2.95, and 2.47, respectively; p<0.05). Willingness to provide biopsy samples was associated with gender and age by year increments (adjusted OR 1.72 and 1.02, respectively; p<0.05). Conclusions: Caucasians significantly preferred providing a new blood sample, whereas older males preferred providing an extra biopsy. Despite the vast majority agreeing to the potential benefit of additional sampling, only half were willing to provide a new biopsy sample. Patient uptake of testing and use of targeted drugs in cancer patients are affected by socio-cultural attitudes and patient demographics. Since most tests have been developed for biopsy samples only, improved patient education and efforts to design blood-based markers may improve uptake of genetic and PGTs. Funding: Alan Brown Chair in Molecular Genomics firstname.lastname@example.org
ATP-Binding Cassette Transporter A1 (ABCA1) Associated with Markers of Instability in Human Atherosclerotic Carotid Plaque Daniel-Costin Marinescu, Robert J. Doonan, Stella Daskalopoulou Montreal General Hospital, Faculty of Medicine, McGill University, Montreal, Quebec, Canada. Rationale: A key feature of atherosclerosis is the infiltration of macrophages within the arterial wall. Once deposited, these macrophages become foam cells by engulfing cholesterol and lipid, forming the core of an atherosclerotic plaque whose composition is the principal determinant of its susceptibility to rupture, also termed its â€˜stabilityâ€™. To prevent and reverse the deposition of lipid within macrophages, these cells express ATP-binding cassette transporter A1 (ABCA1), a transmembrane protein that expels cellular cholesterol and lipid, transferring it to apoliporotein A1 in the bloodstream. Coupled to the lipoprotein, the lipid then travels to the liver for biliary excretion, completing a cycle called reverse cholesterol transport. Previous studies have shown that overall ABCA1 expression is decreased in atherosclerotic plaque as compared to healthy vessels, suggesting that this transporter plays a role in lipid accumulation within plaque. However, it has yet to be investigated how ABCA1 expression compares between plaques of varying degrees of instability. Objective: To investigate a possible relation between ABCA1 and atherosclerotic plaque stability. Methods: Samples of carotid plaque were obtained from 93 patients undergoing endarterectomy. The plaques were stained for ABCA1 as well as CD68 and von Willebrand factor (vWF), two markers associated with instability. After quantifying each of these molecular targets under the microscope, noting both expression levels and intensity of staining for ABCA1, a Chi square analysis was conducted to determine any association between ABCA1 and the two markers of plaque vulnerability. Results: A positive association was found between expression and intensity of ABCA1 and CD68+ foam cells (0.009 and 0.003, respectively) as well as ABCA1 quantity and vWF (0.049). The result suggests a relation between ABCA1 and plaque instability wherein ABCA1, although poorly expressed in plaque compared to healthy vessels, is nonetheless upregulated as atherosclerosis progresses. We propose that this is a response aiming to remove choleresterol and maintain lipid homeostasis in the face of an increasing number of foam cells and increasing plaque instability. Conclusion: ABCA1 is positively associated with plaque instability. Given the possibility of manipulating this association for therapeutic purposes, the physiological mechanism by which this correlation is mediated warrants additional investigation
Lightning Oral SESSION 4
Procurity Lecture Theatre, Apotex Building Main Floor, Room 164 15:30 â€“ 17:00 Wednesday, June 5th, 2013
Clonal tracking studies reveal heterogeneity in mammary stem cell potential – implications for breast cancer treatment Long V. Nguyen1, Maisam Makarem1, Annaick Carles2, Nagarajan Kannan1, Pawan Pandoh3, Peter Eirew1, Melanie Kardel1, Alice M.S. Cheung1, William Kennedy1, Kane Tse3, Thomas Zeng3, Yongjun Zhao3, Connie J. Eaves1, Martin Hirst2,3. 1Terry Fox Laboratory, BC Cancer Agency, 2Centre for High-Throughput Biology, Department of Microbiology & Immunology, University of British Columbia, and 3Canada’s Michael Smith Genome Sciences Centre, BC Cancer Agency. Vancouver, Canada. Rationale: Breast cancer is a major cause of death in women worldwide. Among the most aggressive and unresponsive to therapy are those classified as ER-, PR-, HER2- (triplenegative) breast tumours. However, genomic analyses have demonstrated further extensive heterogeneity between and within individual tumours of this type. A contributing source of this heterogeneity might be the mammary cells in which oncogenic mutations develop and accumulate suggesting the importance of a better understanding of the heterogeneity of differentiation and growth potential of normal mammary epithelial cells. Methods: We developed and deployed a strategy to simultaneously track the in vivo outputs of 100’s of clones of mouse and human mammary cells with high sensitivity and specificity using a library of lentiviruses containing >2x105 different 27 base pair non-coding DNA barcodes to transduce and uniquely mark a starting cell population of purified “stem-cell enriched” basal mammary cells prior to their transplantation into syngeneic and xenogeneic (immunodeficient) recipient mice, respectively. Results: We found that 2.4 x 105 mouse and 6 x 104 human basal cells generated 181 and 56 uniquely barcoded clones after 7 and 4 weeks in vivo, respectively, which ranged in size from ~100-104 cells. In both cases, luminal cells were the only lineage detectable in the majority of these clones, whereas clones identified in secondary recipients were predominantly bi-lineage (containing both basal and luminal cells). In addition, many of the clones detected in the secondary recipients, were derived from cells not detectable in the primary recipients. Conclusions: These results reveal an unexpected degree of heterogeneity in the growth and differentiation activity of mammary stem cells of both mouse and human origin, as exemplified by clones that at first appeared lineage-restricted and later demonstrated bi-lineage potential, and clones that at first remained latent but later could be activated to proliferate. These experiments set the stage for further molecular studies to investigate the instrinsic programs that regulate these various patterns of clonal growth and differentiation, which may be relevant to the perturbed regulation of these properties in the cancer stem cells of different patients’ breast tumours.
Funding: Vanier CIHR – BC Cancer Agency MD/PhD Studentship email@example.com 62
Development of a Targeted Microbubble Contrast Agent for the Molecular Imaging of Endothelial Progenitor Cell Engraftment Nathan Roth1,2, Joshua Rosenblat1,3, Christine Liao1, Dmitriy Rudenko1, Michael A. Kuliszewski1, Howard Leong-Poi1 1Keenan Research Centre in the Li Ka Shing Knowledge Institute, Division of Cardiology, St. Michael’s Hospital, University of Toronto. Toronto, Canada; 2 School of Medicine, Queen’s University. Kingston, Canada; and 3Schulich School of Medicine, Western University. London, Canada. Background: Non-invasive imaging of exogenously delivered endothelial progenitor cells (EPCs) would provide important insights into EPC engraftment, and aid in the refinement of regenerative strategies to promote revascularization within ischemic tissue. Objective: To develop and optimize a non-invasive molecular imaging strategy capable of monitoring exogenously delivered endothelial progenitor cell (EPC) engraftment using targeted microbubbles and contrast-enhanced ultrasound (CEU). Methods: Rat bone marrow-derived EPCs were isolated and transduced using an Adenovirus (Ad-eGFP-H2Kk) to express the unique cell-surface protein H-2Kk. The MOI, transfection efficiency and duration of expression were optimized and confirmed using flow cytometry and immunohistochemistry (IHC). Isotype-control microbubbles (MBC) and H-2Kk-targeted microbubbles (MBH-2Kk) were constructed and used in a flow chamber to assess the in vitro binding capacity of targeted microbubbles to H-2Kk expressing and control-EPCs at physiologic flow rates. CEU imaging of targeted and control-microbubbles was assessed in vivo by imaging H-2Kk-transduced EPCs in engrafted and non-engrafted vascular networks. Results: Transfection of H-2Kk/eGFP was highest, with negligible levels of cytotoxicity, at a MOI of 500. IHC and flow-cytometry data showed that transduction of H-2Kk/eGFP (MOI500) peaked at 72-hours with >90% of cells positive and persisted out to day 7. In flow chamber experiments (n=6), there was a significantly higher level of specific binding of MBH-2Kk to H2KK-transduced EPCs as compared to control-EPCs. Targeted CEU demonstrated marked signal enhancement from MBH-2Kk in the H-2Kk-transduced EPC-engrafted vascular networks, with only minimal signal from MBC (n=5). Conclusions: EPCs can be genetically engineered to express a unique cell-surface marker that can be targeted via specific microbubble contrast agents used in CEU—providing the basis for the development of a non-invasive molecular imaging strategy for EPC engraftment.
Funding: Canadian Institutes of Health Research (CIHR) Email address: firstname.lastname@example.org 63
Targeting fatty acid metabolism: a novel chemosensitizing approach for castrationresistant prostate cancer Lavarnan Sivanathana, Annabelle Chowb and Urban Emmeneggerbc aFaculty of Medicine, b Sunnybrook Research Institute, and cDepartment of Medicine, Sunnybrook Health Sciences Centre and University of Toronto, Toronto, Canada. Rationale: Metastatic prostate cancer, the most frequent cancer in Western males, is treated with androgen-deprivation therapy (ADT) as the standard first-line therapy. However, inevitably ADT-resistant prostate cancer (i.e, castration-resistant prostate cancer, CRPC) develops, usually within 2-3 years. CRPC accounts for most prostate cancer related deaths, and it is largely resistant to treatments such as chemotherapy. CRPC cells secure energy through glycolysis, through fatty acid metabolism that is regulated by the the peroxisome proliferatoractivated receptor alpha (PPARa) pathway, and through autophagy. Both fatty acid metabolism and autophagy are thought to contribute to the chemoresistance of CRPC. Objective: To use a novel, specific PPARa antagonist (SubstanceF) to inhibit fatty acid metabolism and thereby chemosensitizing CRPC to different anticancer therapies. Methods: By utilizing MTS proliferation assays, we assessed the response of autophagy-intact and autophagy-deficient variants of CRPC cell lines (PC-3, C4-2) to the following treatments: SubstanceF alone, SubstanceF combined with the conventional chemotherapy drugs docetaxel and doxorubicin, and SubstanceF in combination with the glycolysis inhibitor 2-Deoxy-D-glucose (2-DG). Results: SubstanceF alone was only effective in reducing the proliferation of autophagydeficient C4-2 cells. When combined with docetaxel and doxorubicin, SubstanceF unexpectedly promoted the proliferation of all CRPC cell variants tested. However, SubstanceF significantly reduced the proliferation of all cell lines tested when combined with 2-DG, even though 2-DG alone had only very weak antiproliferative properties. Conclusion: Our results suggest that pharmacological PPARa inhibition does not sensitize prostate cancer cells to conventional cytotoxic agents such as docetaxel and doxorubicin. Nonetheless, SubstanceF appears to be a promising combination partner for numerous anticancer agents in clinical testing that interfere with the glycolytic pathway such as 2-DG.
Funding: A.E. Tiffin Foundation, Prostate Cancer Canada, CREMS program at the University of L.email@example.com 64
Epidemiology of spinal infections: a chart review of osteomyelitis, discitis, & epidural abscesses. Jasmin Switzer Med II, Kotoo Meguro MD, FRCSC. Division of Neurosurgery, Department of Surgery, College of Medicine, University of Saskatchewan. Rationale: Spinal infections are one of the most difficult, complex, and multi-disciplinary health conditions faced by health professionals. The complexity and diversity of the causes, symptoms, and treatments has made spine infections a challenge for doctors in a number of fields. Although numerous literatures have been published, clear guidelines for management are lacking. Objectives: The purpose of this paper was to gather demographic information of the patients with spinal infections and to determine clinical characteristics of such patients which could influence outcomes. Methods: Charts from 96 adult patients with osteomyelitis, discitis or epidural abscesses admitted to the Royal University Hospital at the University of Saskatchewan from 2007-2011 were analyzed retrospectively. Many aspects of patient information were entered into a database from the charts, and then a data analysis of this information was performed. Results: Of the patients studied, 62% were male and 38% female, 35% of patients required surgery, 45% were IV drug users, and 15% had a poor outcome measure (based on outcomes measured using the Modified Rankin Scale). Five variables were isolated as being statistically significant in relation to poor patient outcomes. These were the presence of a neurological deficit, higher white blood cell count, positive biopsy result, shorter time before disease diagnosis, and longer hospital admission. Except for the duration of admission, these factors could be used to predict the prognosis of patients. There appears to be two general groups of patients, one being patients with slow, indolent courses of illnesses, and the other being patients with acute and rapidly deteriorating courses. The former may be more difficult to make a diagnosis because the symptoms are vague, and the latter may be more challenging in terms of the treatment. It would be important to distinguish between these two groups of patients before starting treatment. Conclusions: Spinal infections are serious conditions requiring long hospital admissions, extended treatments with antibiotics, and the involvement of numerous specialists. As such, spinal infections create a great burden to the health care system. The variables associated with poorer outcomes would alert clinicians when treating patients with spinal infection.
Funding: University of Saskatchewan, College of Medicine. Contact Information: firstname.lastname@example.org, email@example.com 65
Bridging the gap between open and minimally invasive pancreaticoduodenectomy: the hybrid approach Yifan Wang, Sabrina Piedimonte MSc, Simon Bergman, MD MSc, Tsafrir Vanounou, MD MBA Department of General Surgery, Jewish General Hospital, Montreal, QC, Canada Rationale: Minimal access pancreatic surgery has evolved rapidly, but total laparoscopic pancreaticoduodenectomy is not widely performed due to its technical complexity. Hybrid laparoscopy-assisted pancreaticoduodenectomy (HLAPD) combines the safety of open surgery with the benefits of a minimally invasive approach. The aim of this study is to evaluate the efficacy of the hybrid approach as an intermediary procedure which can be adopted by hepatobiliary surgeons without extensive laparoscopic experience. Methods: We retrospectively analyzed data of patients undergoing either hybrid or open pancreaticoduodenectomy (HLAPD, n = 11; OPD, n = 17) at our institution between September 2009 and January 2013. Demographic characteristics, surgical outcomes and oncologic markers were collected to compare outcomes between HLAPD and OPD. Results: There were no differences in patient demographics, co-morbidities or surgical indications. The HLAPD group had significantly lower intraoperative blood loss (400 vs. 1050 mL, p = 0.047) and shorter length of hospital stay (9 vs. 13.5 days, p = 0.022) compared to the OPD group. Operative time did not differ significantly between the two groups. There were no differences in post-operative analgesic requirements, Clavien grade I/II or grade III/IV complications, or 30- or 90-day mortality rates. Oncologic outcomes showed no significant differences in tumor size, R0 resection rate and lymph node harvest. Conclusions: In selected patients, HLAPD is a safe and oncologically sound procedure with comparable outcomes to conventional open surgery. Wider adoption of the hybrid approach as an intermediary procedure will facilitate the transition towards minimally invasive pancreatic surgery without incurring additional risk to patients.
Funding: Medical student research bursary, Faculty of Medicine, McGill University Yifan.firstname.lastname@example.org 66
Effects of AMD-associated factors: CFH Y402H polymorephism, age and drusen, on ocular vitreoretinal environment Jay Ching-Chieh Wang, Sijia Cao, Geoffery Law, Aikun Wang, Jing Cui, Joanne A. Matsubara Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, BC, Canada PURPOSE: Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly of developed countries. Recent studies suggest that complement activation and oxidative stress contribute to local retinal inflammation, an important feature in AMD development. Advanced age, drusen load and complement factor H (CFH) Y402H (T>C) polymorphism have been shown to be associated with AMD risk and progression. However, how these factors affect the vitreoretinal environment require further investigation. We assessed pro-inflammatory cytokines in the vitreous and retina of post-mortem donor eyes in relationship to these factors. METHODS: Twenty-two pairs of post-mortem non-diseased donor eyes, with average postmortem collection time of 14.53 hours, were used. The right eyes were paraffin-embedded to assess for drusen load and immunohistochemical staining of IL-18 and C3a. The left eyes were dissected for collection of vitreous and retina, which were used for analysis of cytokine levels using BioplexTM and CFH genotyping, respectively. Comparisons were made between these groups: CC VS TT eyes, younger (≤55 year-old) vs older (≥70 year-old) eyes and drusen vs no drusen eyes. Data were analyzed by Student’s t test. We also assessed the post-mortem, time-dependent changes in the cytokine levels in vitreous of a rodent model collected at 0, 10 and 20 hours after sacrifice with BioplexTM. RESULTS: Rat vitreous cytokine levels were higher at 0 hour but stayed unchanged between 10 and 20 hours after sacrifice, supporting the method of postmortem vitreous sampling used in this study. Eyes with at-risk variant (CC) show significantly increased basic-FGF and G-CSF level (p<0.05) compared to normal eyes (TT). Older eyes exhibited higher IP-10 than younger eyes (p<0.05). Eyes with drusen showed significantly increased IL-9 and GM-CSF (p<0.05), while IL-4, IL-7 and IL-13 showed marginally significant increase (p<0.15). Immunohistochemistry suggested increased C3a and IL-18 staining in eyes with CC variants. Conclusion: Our data suggest CFH Y402H mutations, increased drusen load, and increased chronological age are associated with increased vitreoretinal cytokine expression. The data demonstrate a relationship among the AMD risk factors and the local vitreoretinal environment. Further studies are needed to understand these vitreoretinal changes and their role in pathogenesis of AMD.
Funding: CIHR HPSRA, UBC SSRP, BCCGN Contact information: Jay Ching-Chieh Wang email@example.com 67
NOVEL BIOMARKERS IN PEDIATRIC NEUROBLASTOMA Alexandra Kuzyka, John Gartnerb and Sabine Maia aDepartment of Biochemistry and Medical Genetics, bDepartment of Pathology, University of Manitoba. Winnipeg, Canada. Rationale: Clinically poor prognostic factors of human neuroblastoma (NB) include N-Myc overexpression and gain of chromosome arm 17q; however, these are inconsistent predictors and new biomarkers are needed. Cytoband 11E2 in mouse, and its human (17q25) and rat (10q32) synteny regions, is aberrant in many aggressive tumors and has been implicated as a potential oncogenic cluster. Previously we identified that cytoband 11E2 in fast-onset mouse plasmacytoma (PCT) is duplicated, overexpressed, has a significantly different nuclear localization (P = 0.007) and has selectively longer telomeres (P = 4x10-16) than in wild-type mice. Furthermore, we have identified distinct telomere profiles for many diseases and propose that 3D telomere organization has prognostic capability. Therefore, we hypothesize that 3D telomere organization and copy number of cytoband 17q25 may be novel biomarkers to differentiate aggressive from non-aggressive pediatric NBs. Methods: Fluorescence in situ hybridizations (FISH) are conducted with cytoband 17q25 and telomere probes that label all copies of cytoband 17q25 and telomeres, respectively, in 2D metaphases and 3D nuclei from NB patient-derived cell lines and in 3D nuclei from primary NB patient tissue samples. The N-Myc levels were previously characterized in the cell lines and patient samples. Results: In aggressive neuroblastoma cell lines and patient samples, the copy number of cytoband 17q25 is increased. A high N-Myc expressing human neuroblastoma cell line (IMR-32) has five copies of cytoband 17q25 in metaphases and 3D persevered interphase nuclei whereas a low N-Myc expressing cell line (SH-EP/SF) has only three copies. Similarly, N-myc amplified neuroblastoma patient samples exhibit five and six copies of cytoband 17q25 but nonamplified tumor tissue has only three copies. Non-tumor lymph node tissue from the same patient has the normal two copies of 17q25. 100% of nuclei from both N-myc amplified and nonamplified patient tumors contain telomeric aggregates; however the N-myc amplified tumors have fewer telomeric signals and more aggregates, which are characteristics of highly aggressive tumors. Conclusions: 3D telomere organization and an increased copy number of cytoband 17q25 may be novel biomarkers for aggressive neuroblastoma. This may lead to future clinical applications through the development of screening tests that can better stratify patient populations and personalize treatments.
A longitudinal study on the value of the methacholine challenge test as a diagnostic aid for asthma in high-risk adolescents Maggie Onga, Allan Beckerb, Moira Chan-Yeungc, Edmond Chand, Clare Ramseye Faculty of Medicinea, Dept. of Pediatrics and Child Healthb, Dept. of Medicinee, University of Manitoba, Winnipeg, MB, Canada, Dept. of Pediatricsc, Dept. of Medicined, University of British Columbia, Vancouver, BC, Canada.
Rationale: Airway hyperresponsiveness (AHR), which is a cardinal feature of asthma, is commonly measured by a methacholine challenge test. The measurement derived from this test is the provocative concentration of methacholine at which the forced expiratory volume in one second falls by 20% from baseline (PC20). A PC20 <8.0 mg/mL defines AHR in adults, while a lower cut point has been demonstrated in school-aged children. There is limited data on the cut point in adolescents. Objective: To investigate the utility of the methacholine challenge test as a measure of AHR, in aiding the clinical diagnosis of asthma in adolescents. Methods: The study population comprised 330 high-risk 15-year-olds from the Canadian Asthma Primary Prevention Study (CAPPS), which is a randomized control trial of a multifaceted intervention on asthma prevention. Interventions consisting of reduced exposures to dust mite, pet, and tobacco smoke, maternal and infant dietary modifications, and daycare avoidance were applied over the first year of life. Assessments at age 7 and 15 years consisted of a physician assessment for asthma diagnosis, methacholine challenge, and skin prick testing. Atopy was defined as any positive skin prick test. Receiver operator characteristic (ROC) curves were constructed from sensitivities and specificities for PC20 cut points from 1.0 to 8.0 mg/mL, using physician diagnosis as the gold standard. The area under the curve (AUC) was calculated using the trapezoidal rule. Results: An AUC of 0.71 (95% CI 0.63-0.80) was measured for adolescents with asthma overall, which indicates that the methacholine challenge is a â€œfairâ€? test. This is an improvement from the AUC at age 7 years. When stratified by sex and atopy, the presence of atopy was associated with higher AUCs, particularly amongst females (Table 1). The PC20 cut point with the highest sensitivity and specificity for asthma was â‰¤ 5.5 mg/mL, which is an increase from the cut point at age 7 years. Conclusions: The methacholine challenge test is useful in assisting the diagnosis of asthma in adolescents overall, but not in non-atopic adolescent females where it is equivalent to a coin toss. Its utility appears to improve with age from childhood to adolescence.
Funding: CIHR, AllerGen NCE Inc. firstname.lastname@example.org
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Published on May 30, 2013
Compendium of research abstracts presented orally and via poster competition at the 2016 Canadian National Medical Student Research Symposiu...