You Might Hear A Cricket Chirp
Ormia ochracea is a tiny, parasitical fly and the bane of crickets. The fly listens for cricket chirps, homes in and deposits larvae on the back of the cricket’s back. The larvae then proceed to burrow into the cricket and eat it alive.
While this scenario is nothing for crickets to sing about, it’s absolute inspiration for researchers trying to develop the next generation of directional hearing aids, who describe a new, fly-inspired prototype in the journal Applied Physics Letters.
What’s particularly notable about the fly’s hearing abilities is that they derive from ears that are, well, extremely small. Human ability to detect the source and direction of sounds derives significantly from our large heads and widely separated ears. The latter receive the same sound at slightly different times. Our brains analyze that time difference and use it to locate the sound source.
The heads of flies, though, are just a millimeter or so wide, about the thickness of an average fingernail. (Incidentally, the fly above is resting on a fingernail so you can get a good sense of scale.) Flies overcome their size limitations by creatively tweaking the internal hearing structure. Between the two ears of a fly is a sort of see-saw that moves up and down, amplifying the incredibly small time differences of incoming sounds. It allows the fly to find chirping crickets quite well.
Researchers at the University of Texas have used the fly’s ear structure as a model to create minute pressure-sensitive devices out of silicon that they hope can eventually be used in new directional hearing aids that are smaller, more comfortable and longer-lasting.
Liver Scarring Mechanism Identified In Mice
The human liver may be our most undervalued organ.
Not only does it have lizard-like regenerative powers, its eight connected lobes work round the clock to detoxify us of our vices – be they a slab of fatty steak or a flagon of beer.
When we aren’t being bad, and even when we are, the liver also helps us digest our food, store energy and vitamins (it can hold several years’ worth of B-12), and clear our blood of residues from taking medications. It even plays a role in maintaining our hormonal balance and keeping our bones strong.
It does all of this if that meaty three-pound organ under the right side of our ribcage is working properly. If the liver becomes diseased, many vital bodily processes can go awry.
Regardless of the type of assault or insult, the liver almost always shows signs of abuse by forming fibrous scar tissue, which can further impair the liver’s ability to function, with profound health consequences.
Reporting in the current issue of Proceedings of the National Academy of Sciences, researchers at the University of California, San Diego School of Medicine have described a fundamental mechanism underlying the progression of cholestatic liver fibrosis, which is caused by the impairment of bile formation or bile flow not by lifestyle choices, like heavy drinking.
“Our study puts into perspective many previously contradictory studies, and provides a general approach to understanding the distinct mechanisms which lead to liver scaring and fibrosis,” said senior author Tatiana Kisseleva, MD, PhD and an assistant professor in the Department of Surgery. Fibrosis refers to progressive liver scarring, occurring in most types of chronic liver disease.
In the study, researchers identified a type of cell in the livers of mice (portal fibroblasts) that respond to bile-related liver injuries. When these cells become activated and proliferate, they secrete fibrous scar tissue.
Though the study was conducted in mice, preventing the activation of these cells in human livers could help prevent liver scarring in people with cholestatic liver disease.
Toward this effort, the scientists have now identified novel markers of activated portal fibroblasts that could be used to evaluate the source of liver injury in patients.
Steffanie Strathdee became involved in HIV/AIDS research at the University of Toronto after one of her professors failed to show up for class. “He had died of AIDS,” Strathdee said. “Later I lost my PhD supervisor and my best friend to the disease as well, so for me, coming to work in the HIV/AIDS field was a calling, something I had to do.”
The journal Lancet offers a nice profile of Strathdee’s work in its current online edition. Strathdee is associate dean of Global Health Sciences and chief of the Division of Global Public Health in the Department of Medicine at UC San Diego. An infectious disease epidemiologist, she has focused her research over the past two decades on HIV prevention in underserved, marginalized populations in developed and developing countries, including injection drug users, men having sex with men and sex workers.
The U.S.-Mexico border is a particular focus. Strathdee is one of the leaders of the Health Frontiers in Tijuana project, in which a student-run free clinic provides health services to marginalized populations, in collaboration with the UC San Diego School of Medicine and Tijuana’s Autonomous University of Baja California School of Medicine.
Not coincidentally, Strathdee was also recently featured as one of 40 women offering thoughts and wisdom in a San Diego exhibition called Notes to Our Sons & Daughters.
Photograph courtesy of Pablo Mason/Notes to Our Sons & Daughters project. 2014. Alexis Dixon.
Study gives promise to new treatment for appendix cancer
Appendix cancer is rare, with approximately 600 to 1,000 new patients diagnosed each year and an estimated 10,000 currently living with the disease. Because it is rare, few studies have been devoted to this cancer and standard treatment for appendix cancers relies upon the same chemotherapy drugs used for colorectal cancer. A new study by researchers at the University of California, San Diego School of Medicine has found that genetic mutations in appendix and colon cancers are, in fact, quite different, suggesting that new and different approaches to appendix cancer treatment should be explored.
The study was published in a recent issue of Genome Medicine.
Cancers are characterized by different gene mutations. Historically, genetic mutations in appendix cancer have been poorly characterized due to its low incidence. The cancer often remains undiagnosed until it is discovered during or after abdominal surgery or when an abnormal mass is detected during a CT scan for an unrelated condition.
The primary treatment of localized appendix cancer is surgical but treatment for patients with inoperable appendix cancer has been limited to therapies developed for colorectal cancer. Although the chemotherapy drugs used for colorectal cancer dramatically improve patient outcomes, they have not proven to be as successful in patients with appendix cancer.
“We have been treating appendix cancer like colorectal cancer because it was thought to be the most similar tumor type, but this study identifies the signature differences between these two cancers,” said Andrew Lowy, MD, FACS, a senior author of the study and professor of Surgery at UC San Diego School of Medicine. “These findings suggest opportunities to develop novel therapies that specifically target appendix cancer.”
The study initially evaluated 10 cases, nine with low-grade appendix cancers and one with high-grade cancer. The results from this group were then validated with 19 additional cases.
The results also identified a gene mutation in appendix cancer that is commonly found in a form of pancreatic cancer, which typically spreads rapidly and is seldom detected in its early stages.
“The study’s results are promising for patients. We now have a more in-depth knowledge of the biological make up of appendix cancers, which allow for a more customized approach,” said Lowy, who also serves as chief of the Division of Surgical Oncology at UC San Diego Health System. “The goal is to now conduct more studies that will test specific treatments targeted to these unique genetic mutations.”
To learn more about cancer treatments at UC San Diego Health System, visit cancer.ucsd.edu
Image: A histopathological photomicrograph depicting cancerous cells in the appendix.
A Moveable Yeast: modeling shows proteins never sit still
Our body’s proteins – encoded by DNA to do the hard work of building and operating our bodies – are forever on the move. Literally, according to new findings reported by Trey Ideker, PhD, chief of the Division of Genetics in the UC San Diego School of Medicine, and colleagues in a recent issue of the Proceedings of the National Academy of Sciences.
Hemoglobin protein molecules, for example, continuously transit through our blood vessels while other proteins you’ve never heard of bustle about inside cells as they grow, develop, respond to stimuli and succumb to disease.
To better understand the role of proteins in biological systems, Ideker and colleagues developed a computer model that can predict a protein’s intracellular wanderings in response to a variety of stress conditions.
To date, the model has been used to predict the effects of 18 different DNA-damaging stress conditions on the sub-cellular locations and molecular functions of more than 5,800 proteins produced by yeasts. They found, for example, that yeast proteins could move from mitochondria to the cell nucleus and from the endoplasmic reticulum to Golgi apparatus.
Though the model debut involved yeasts, researchers said the coding can be adapted to study changes in protein locations for any biological system in which gene expression sequences have been identified, including stem cell differentiation and drug response in humans.
Image courtesy of Material Mavens
Food for thought
Admittedly there’s no known scientific or therapeutic value to the brain image above. It’s not likely to satisfy our hunger for knowledge in, say, the way a tractograph or fMRI might. Instead, it’s just likely to make you hungry – for more.
Feast your eyes on Sara Asnaghi’s similar cerebral takes of the edible brain here.
UC San Diego Health System Among “Most Wired Advanced” in Nation -
Only 20 institutions garner top designation on Hospitals & Health Networks’ annual survey
UC San Diego Health System is among the nation’s “Most Wired Advanced” hospitals, according to new findings released by Hospitals & Health Networks (H&HN), a publication of the American Hospital Association. The designation – given to just 20 of 375 hospitals cited – highlights institutions that have most effectively leveraged information technologies to improve performance and patient care.
The 16th Annual Health Care’s Most Wired Survey covers 1,900 hospitals, roughly one-third of the nation’s total. It evaluates how hospitals use information technologies in five areas: business processes, customer service, safety and quality, workforce and public health, and safety. It identified 375 hospitals and health systems, ranging in size from 25 beds to more than 10,000, as “most wired.” Seventeen are based in California.
Read more here
Parents Rank Their Obese Children as “Very Healthy” -
A University of California, San Diego School of Medicine-led study suggests that parents of obese children often do not recognize the potentially serious health consequences of childhood weight gain or the importance of daily physical activity in helping their child reach a healthy weight.
The study is published online in the Journal of the Academy of Nutrition and Dietetics.
“Parents have a hard time changing their child’s dietary and physical activity behaviors,” said lead author Kyung Rhee, MD, and an assistant adjunct professor in the Department of Pediatrics. “Our study tells us what factors may be associated with a parent’s motivation to help their child become more healthy.”
The study is based on a survey of 202 parents whose children were enrolled in an obesity clinic at the Hasbro Children’s Hospital in Providence, Rhode Island in 2008 and 2009. The survey probed parents’ readiness to take actionable steps to improve their child’s eating habits and physical activity levels. The children ranged in age from 5 to 20 years old, with an average age of 13.8 years. More than two-thirds were female, and almost all (94 percent) were clinically classified as obese.
Although most of the children had been referred to the obesity clinic by a primary care provider and had metabolic markers of obesity, 31.4 percent of parents perceived their child’s health as excellent or very good and 28 percent did not perceive their child’s weight as a health concern.
Parents indicated a greater interest in helping their child eat a healthy diet than encouraging the pediatrician-recommended hour of daily physical activity.
Specifically, 61.4 percent of parents reported that they were improving their child’s eating habits (less junk food, more fruits and vegetables) while only 41.1 percent said they were increasing their child’s involvement in active play, sports, dancing or even walking. Both diet and exercise are considered keys to good health, and a growing body of evidence suggests that these health habits are formed early in life.
Parents who had talked with their primary care physician about healthy eating strategies were more likely to be in the “action stage of change” with their child’s diet. By contrast, parents who viewed their own battle with weight as a health concern were less likely to be addressing their child’s eating habits.
The researchers said education, income and race/ethnicity had no statistically significant bearing on a parent’s likelihood of making dietary changes for their child.
In terms of physical activity, researchers do not know why parents appear to under-emphasize its role in good health, but the finding is consistent with other recent studies that suggest America’s youth are largely out-of-shape and sedentary, replacing playtime with “screen time.”
Experts say one strategy to counteract the trend may be to intervene early. Parents with children 14 or older were much less likely to be successful in helping their child develop a physical dimension to their life than parents of younger children.
Poverty may also play a role in how much children move on a daily basis, as parents with annual incomes of less than $40,000 were also less likely to be actively engaged in ensuring their child got regular exercise.
Fighting dead zones of cancer
Almost all high-risk, poor-prognosis cancers have very low levels of oxygen in the primary tumor’s interior. A marker for this oxygen-depleted state is the presence of a protein known as H1FI alpha.
In healthy cells, HIF1 alpha is degraded into harmless nothingness in the cytoplasm. In low-oxygen cancer cells however, the normal breakdown goes awry and HiFl alpha is able to enter the nucleus, where it may activate genes that further promote aberrant cell growth.
A new study conducted by researchers at the University of California, San Diego School of Medicine shows that an emerging class of anticancer treatments known as PI-3K inhibitors help to degrade the HIF1 alpha protein and thus may offer a potential therapy for treating deadly hypoxic tumors. The study was published in a recent issue of the Journal of Biological Chemistry.
“Our main finding is that, in the absence of PI-3K signaling, MDM2 proteins cannot go inside the nucleus,” said lead author Shweta Joshi, PhD, postdoctoral researcher. “In the cytoplasm, the MDM2 proteins degrade HIF1 alpha. This is good news because it means that some new cancer therapies may help patients in more ways that was initially realized.”
"These HIF1 proteins are major players in driving the cancer state," said co-author Donald Durden, MD, PhD, professor and vice chair for Research in the Department of Pediatrics and research director, Division of Hematology/Oncology at the UC San Diego Moores Cancer Center. “They control degradation of surrounding tissues, induce a change in metabolism and induce the formation of blood vessels. That is why our observation is so important, because it reveals an entirely new way of HIF1 regulation.”
Pictured: A false-color, scanning electron micrograph of two cultured HeLa cancer cells, courtesy of Thomas Deerinck, National Center for Microscopy and Imaging Research at San Diego.