6 wednesday, february 1, 2012
Nanoparticles deliver triple blow to tumors New chemo delivery system allows for more effective cancer treatment
By HUDSON LOFCHIE Aggie Science Writer
The fight against cancer has been long and arduous. Researchers have made the occasional advance in treatment, but as of yet, cancer is still at large. However, a group of researchers based at UC Davis has made a major advance in cancer treatment that will dramatically augment our ability to fight cancerous tumors. This advance is not a new drug or medication, but instead a new delivery method. Researchers created a nanoparticle, called a micelle, that holds cancer medications inside and will only release the drug once it is inside a tumor. Since the medications are only released within the tumor, doctors can administer far higher dosages of cancer drugs without having to worry about toxicity to the rest of the body. “We [could] only give 15mg [of chemo] per kilogram of weight, otherwise the subject dies because too much [medication] goes into their system and is toxic,” said Kit Lam, professor and chair of the department of biochemistry and molecular medicine at UC Davis. The micelles are con-
glomerations of smaller molecules that each have a hydrophobic (wateravoiding) and hydrophilic (water-attracted) end. The molecules are specifically designed by the researchers to have these properties and are constructed through a basic peptide chemistry process. When these small molecules are dispersed into a water-based solution, they automatically assemble into micelles. Depending on how the molecules are constructed, they can be “tuned” to respond to changes in pH (acidity). “The micelles ... are stable during blood circulation and release the [medication] quickly when triggered by the acidic microenvironment of a tumor,” said Yaunpei Li, a post-
doctoral fellow in Lam’a lab, and first author of the study. “Our micelle could prevent premature drug release [into the body].” While chemotherapy remains a very effective treatment for cancer, it is limited by its toxicity to the rest of the body. In high concentrations, it will not only kill cancer cells, but all of your healthy cells as well once it disperses throughout the body. Since these new micelles are tuned to the specific pH of a tumor, they ensure that nearly 100 percent of the drugs go directly to the tumor and not to the rest of the body. “With this micelle, we can deliver up to three times the dosage because all of it goes directly to the tumor,” Lam said.
Micelles have been used in the past as a drug delivery system, but until now, they were relatively unstable and bore the risk of prematurely releasing the medications. “We used cross-linking to improve over past micelles,” said Juntau Lau, an assistant professor of pharmacology at State University of New York (SUNY) Upstate Medical University and one of the authors of the study. “The new micelles better maintain their chemical structure to prevent disassociation (breaking apart).” As of now, the micelles are only effective against solid tumors, and not against blood cancers like leukemia or lymphoma. However, the researchers were confident that with a little more work, they can make micelles that will be effective against not only blood cancers, but against many other diseases and even inflammation. Perhaps the most important part of this advance is that since the micelles deliver most of the medication to the tumor, there is very little dispersed within your system to cause negative side effects such as nausea and hair loss. HUDSON LOFCHIE can be reached at email@example.com.
Teaching compassionate medicine via a web-tool Medical students learn to deal with end of life situations
By ERIC C. LIPSKY Aggie Science Writer
Society continues to consume an increasing amount of its media in more interactive ways, in terms of music, videos and games. The medical community is also taking steps to provide its students with the tools to make learning more engaging and convenient. More specifically, medical students are gaining a new way to learn how to deal with end of life situations as a result of the eDoctoring program created by top medical professionals throughout California. The program aims to better prepare medical students for real end of life situations and increase learning by making the process more intuitive. “Doctors in California were doing poorly in issues pertaining to dying and end of life,” said Michael Wilkes, director of global health at the UC Davis School of Medicine. “The state advised med-
ical schools around the state to improve these things.” Wilkes, who is the program’s leading expert, said that the program approaches education in a different manner. “Education has always been here and now; at the end of your time, you’re done. This tool makes you take and apply the learning that you’ve gone through,” Wilkes said. The eDoctoring program features interactive videos and scenarios that help medical students get acclimated with situations they will face with patients approaching the ends of their lives. Along with presenting medical students with several aspects of problems a patient might be experiencing, it provides students with feedback on the exercises they partake in. “The program gives hyperlinks and ways to go back and see what you’ve done, and areas where you can improve,” Wilkes said. Wilkes said that the program instructs students in
three critical areas: knowledge, attitude and skills. “We know what patients die of, but what happens in the last few hours of their life? What do they want and feel?” Wilkes said. Wilkes said that students learn to develop an attitude that even though a patient is dying, there are many things that happen before dying; before just giving up on the patient. “In terms of skills, it’s knowing how to apply what has
been learned and the attitudes you’ve developed,” Wilkes said. Mark A. Robinson, master social worker and campus planner at the UC Davis Academic Geriatric Resource Center — a center that advocates training aimed at improving the care provided for aging adults — used his 20 plus years of experience to tune and polish the program.
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The california aggie
get back into the songbird. However, songbirds don’t eat snails. How do they get there? The answer is amazingAmy ly creative, though disturbStewart ing. The parasite forces its way into the snail’s eyestalks and begins pulsating. The eyestalk becomes enlarged from the parasite and makes the snail want to crawl toward sunlight. The songbird, thinking the snail’s eyestalks are a different creature it would like to eat, snatches the eyestalks. Point: leucochloridium. very now and then, Slave-Driving Ant: I like to take a break from looking at the Common names of animals are very helpful for underbeauty of nature to look at standing certain characthe weirder, more terrifying things. For all the beau- teristics of the animal. The most obvious is the slavetiful creativity that nature driving ant. The slave-drivshows in the world around ing ants, officially called us, a close look can also Anergates, invade the nests find creatures that we find of Tetramorium and steal horrifying. their pupae. When they The most likely kind of creature to inspire this feel- hatch, the slave-driving ants make the Tetramorium ing is the parasite. A parants work for them. asite is any organism that Anergates do not make lives at the expense of anworkers of other ortheir own ganism. If you were one of the unequal and cannot Within that huge conjoined twins, you were the even feed themselves definition strong one that absorbed the other without the are two slaves. categories: Unequal endoparConjoined Twin: In conasites and ectoparasites. Endoparasites are parasites trast to slave-driving ants, the official name of conthat live inside of the cells joined twins is much more of host organisms, such as viruses and some species of informative than the common name of Siamese bacteria. Ectoparasites, by twins. For reasons not comcontrast, are parasites that pletely understood, most live outside of the host orlikely incomplete splitting ganisms, such as ticks. of a fertilized egg, causes These definitions are all two individuals to share well and good, but let’s see one or more organs. They some real life examples of could be attached at the parasites. hips, head or any other vaCommon Cuckoo: At riety of locations. their worst times, perhaps An unequal conjoined after weeks of little sleep, a twin, also called a parasitparent may be forgiven for ic twin, is when one twin wanting someone else to is stronger and healthier take care of their children, than the other. The stronat least for a while. For huger twin eventually takes mans, that’s what grandparents or aunts and uncles all of the nutrition from the other twin, resulting in the are for. eventual death of the weakCuckoos, a species of er one. small bird, take this wish Why is this creepy? If quite a few steps further. you were one of the unCuckoos will take their equal conjoined twins, eggs to the nest of anothyou were the strong one er bird species, push the other bird’s eggs out of the that absorbed the othnest and replace them with er. Think of the episode of “The Simpsons” in which cuckoo eggs. When the Bart discovers that he had other bird returns to the an evil twin, only to disnest, they take care of the cover at the end of the epibaby cuckoos while some sode (spoiler alert) that he or all of their own eggs had been the evil twin all have vanished. along. Obviously, there’s There’s a connection no real good-evil binary in here to the old legends of fairies taking human babies this situation; the stronger twin isn’t trying to cause and replacing them with fairy look-alike children for harm, it’s just trying to survive. the human mother to take Why do parasites act care of. in the way that they do? Leucochloridium: Leucochloridium is a genus While it is tempting to asof flatworm that matures in sign the parasite an “evil” the intestines of songbirds. role, that’s not really telling the full story. Take the Well, that’s no fun for the cuckoo; the only reason songbird, but how is that any different from the myr- the adult cuckoo knows which bird species to iniad of parasites that infect vade is because it rememanimals in a similar way? bers what species raised it The Leucochloridium as a hatchling. has to take an indirect and While these are intereststrange path to get to the ing cases, and fun to assign intestine of the songbird. them horror movie plotThe worm lays its eggs in lines, keep in mind these the intestine, which the organisms are only trying songbird then passes out to do the same thing that in its feces. A snail then we are — to survive. makes its way to the feces and eats. The worm eggs are now inside the snail; AMY STEWART can be reached at science@ theaggie.org. they hatch, and now must
Astronomers detect faint satellite galaxy UC Davis professor co-authors paper in Nature magazine By BRIAN RILEY Aggie Science Writer
Chris Fassnacht, a professor in the UC Davis Physics department, has coauthored a paper appearing in Nature, which provides evidence to corroborate a theory of how galaxies form in a process that involves dark matter by detecting a faint satellite galaxy 10 billion light years away. Fassnacht is currently visiting his alma mater, the California Institute of Technology (Caltech), while on sabbatical in Pasadena. It was Caltech astronomer Fritz Zwicky who noticed in 1933 that galaxies were “moving too fast and should have flown apart,” said Fassnacht, leading to the theory of dark matter. By using a larger, nearby galaxy as a “gravitational lens,” when a galaxy functions similar to an optical lens by bending light, Fassnacht and his co-researchers found a way to use sophisticated new
computational techniques to discover the smallest galaxy that was ever discovered at the distances they explored. “The preponderance of the evidence is consistent with General Relativity plus dark matter,” said Fassnacht, referring to Albert Einstein’s theory that space-time is curved, which altered scientists’ view of the structure of the universe. Since the 1920s, the larger Pasadena area, including the nearby Mount Wilson Observatory, has served as an important locus of activity in scientific circles. “Einstein was like a rock star when he was here,” said Loma Karklins, an archivist at Caltech whose son attends UC Davis. During one visit in the winter of 1931, Einstein met with astronomer Edwin Hubble at Mt. Wilson Observatory to reconsider his theories. Hubble had made discoveries regarding specific patterns in the way that light observed emanating from galaxies is shifted to the red side of the spectrum. Hubble “‘put ‘distance’ together with ‘recessional speed,’” said Dave Jurasevich, the superintendent of Mt. Wilson Observatory, explaining how Hubble showed that the universe has a
scale to its expansion. “From 1917 to 1948 the 100-inch [telescope on Mt. Wilson] was the biggest telescope on earth. Hubble had the big picture because he had the biggest telescope on earth,” Jurasevich said. “If your telescope is bigger,” Fassnacht said, “then you can get sharper images.” Fassnacht explained that Mt. Wilson is still an excellent place to do work in the infrared spectrum, but he and his colleagues are doing work in the visible spectrum and chose the Keck Observatory in Hawaii. The telescopes at Keck each have a special, smaller mirror which can be continually adjusted to cancel out much of the “twinkling,” or fluctuation effect, that is caused by the light traveling through the earth’s atmosphere. Computers at Keck can interpret the signal variations in a beam of laser light that is reflected off the sodium layer 90 kilometers up in the atmosphere to make the compensating adjustments, Fassnacht said. The inventor of the laser, Charles Townes, coincidentally is the Chair of the Mount Wilson Institute Board of Trustees, which oversees the operation of the Mt. Wilson Observatory. Just as Fassnacht and his colleagues
are able to make inferences about the sizes of distant galaxies by interpreting subtle geometric patterns of images in the visible spectrum, Townes and
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