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Archive - Jan 2014

January 8th

Scientists Identify Possible Key to Drug Resistance in Crohn’s Disease

Two-thirds to three-quarters of the estimated 700,000 Americans living with Crohn’s disease, an autoimmune condition that can disrupt the entire gastrointestinal tract, will require surgery at some point during their lives. Patients and physicians often turn to this surgical intervention after a patient develops resistance to current treatments, such as steroids. Now scientists from the Florida campus of The Scripps Research Institute (TSRI) have identified a normally small subset of immune cells that may play a major role in the development of Crohn’s disease generally and in disease-associated steroid resistance specifically. The study, published online January 6, 2014 in the Journal of Experimental Medicine, focused on Th17 cells, part of a family of white blood cells that have been implicated in numerous autoimmune diseases, including Crohn’s disease. In the new study, the researchers found that a subset of TH17 cells in humans expresses the multidrug transporter MDR1 and that these cells are linked to inflammation in Crohn’s patients. MDR1—a protein famous for promoting drug-resistance in tumors—may also act as a survival and steroid resistance factor in T cells, particularly in harsh environments such as the inflamed gut mucosa of Crohn’s disease patients. “Our study is the first to identify and characterize this uniquely pro-inflammatory T-cell subset,” said biologist Dr. Mark Sundrud, a TSRI assistant professor who led the study. “We were able to sort these cells directly out of damaged tissue resected from Crohn’s patients and found that these pro-inflammatory cells are over-expressing genes that contribute to disease.” Within healthy individuals, only approximately 5 to 10 percent of CD4+ T cells are MDR1-expressing TH17 cells.

Zone in with Zon—Nucleic Acid Chemist Tackles Direct-to-Consumer Genetic Testing

Dr. Gerald Zon’s latest blog post, dated January 6, 2014, and published by TriLink BioTechnologies of San Diego, focuses on the controversial subject of direct-to-consumer (DTC) genetic testing. Dr. Zon shares some personal history, beginning in 2009, of dealing with Navigenics, the first provider of direct-to-consumer (DTC) SNP-based genetic testing and medical counseling. He then discusses 23andMe, a company that has been a lightning rod of controversy in the area of DTC genetic testing and received a “bombshell” November 2013 letter from the FDA calling on the company to stop marketing its testing kit until it received proper authorization. D. Zon also noted the FDA’s November issuance of marketing authorization for the first high-throughput (next-generation) genomic sequencer (Illumina’s MiSeqDx), which will allow development and use of innumerable new genome-based tests, as described in a December 19, 2013 New England Journal of Medicine Perspective piece by Francis Collins, M.D., Ph.D., and Margaret Hamburg, M.D. Dr. Zon further mentioned the “upbeat “Consumer Genetics Conference,” held in September 2013 to emphasize the swirl of developments and debate in this key arena. According to Dr. Zon, Navigenics began selling its genetic testing services in 2008 based on SNP analysis to assess risk for a variety of common health conditions. In July 2008, California health regulators sent cease-and-desist letters to Navigenics and 12 other genetic testing firms, including 23andMe. The state regulators asked the companies to prove a physician was involved in the ordering of each test and that state clinical laboratory licensing requirements were being fulfilled. Two months later, Navigenics and 23andMe received state licenses allowing the companies to continue to do business in California. Dr.

January 7th

Sage Grouse Threatened by Pole-Perching Ravens

A new study by the Wildlife Conservation Society (WCS), Idaho State University, and the U.S. Geological Survey suggests that habitat fragmentation and the addition of makeshift perches such as transmission polls in sagebrush ecosystems are creating preferred habitat for common ravens that threaten sensitive native bird species, including greater sage grouse (image). The study appears in the January issue of the journal The Condor: Ornithological Applications. Authors include Dr. Kristy Howe of the Wildlife Conservation Society and Idaho State University, Dr. Peter Coates of the U.S. Geological Survey, and Dr. David Delehanty of Idaho State University. The authors looked at 82 raven nests on the U.S. Department of Energy's Idaho National Laboratory land in southeastern Idaho, a sagebrush steppe ecosystem where ravens increased in numbers eleven-fold between 1985 and 2009. The study area has been subject to various alterations such as the addition of transmission lines, roads, and other human construction. Results showed that 58 percent of raven nests were located on transmission poles, 19 percent were in trees, and 14 percent were on other human-made towers. A 31 percent decrease in the likelihood of nesting by ravens was observed for every one kilometer increase in distance away from a transmission line when compared to unaltered areas. The authors noted that the transmission poles are taller than any other object in the study area and that nesting in or near them may afford the raven myriad advantages including a wider range of vision, greater attack speed, and easier take-off. Nesting on the poles may also gain them greater security from predators, range fires, and heat stress.

TGen and Collaborators Receive $4 Million Grant to Focus on RNA Biomarkers of Brain Injuries

In an effort to lower medical costs, identify patients at risk for injury, and speed patient recovery, scientists will attempt to identify a molecular signal that indicates severity of brain injury during a $4 million, five-year federal grant to Barrow Neurological Institute at St. Joseph's Hospital and Medical Center, Phoenix Children's Hospital, and the Translational Genomics Research Institute (TGen) (image). TGen made this announcement in a press release dated December 4, 2013. Additional partners in the study include the University of California, San Francisco and Stanford University. The molecular profile - comprised of extracellular RNAs- could help identify which patients are most at risk for vasospasm after hemorrhagic stroke. Hemorrhagic stroke can occur as: subarachnoid hemorrhage, or the bleeding into the area between the brain and a thin membrane that covers it; ruptured brain aneurysm, which is an abnormal bulge or ballooning in the wall of an artery within the brain. By identifying RNA molecular markers, a new standard of individualized care could be established, enabling medical teams to respond more rapidly to quickly changing health conditions, and allowing earlier intervention to prevent a secondary injury from occurring. "We hope this study will lead to less injury, less testing and cost, and shorter stays in the hospital," said Dr. Yashar Kalani, M.D., Ph.D., a resident physician in Neurological Surgery and assistant professor at the Barrow Neurological Institute and one of the study's principal investigators. Additional investigators at Barrow include Drs. Robert Spetzler, Peter Nakaji, Felipe Albuquerque, and Cameron McDougall. Vasospasms are characterized by bleeding in the brain that causes irritation and nearby blood vessels to spasm and narrow.

January 6th

Mystery m6A Modification of mRNA Governs Half-Life of Molecule

Researchers had known for several decades that a certain chemical modification exists on messenger ribonucleic acid (mRNA), which is essential to the flow of genetic information. But only recently did experiments at the University of Chicago show that one major function of this modification governs the longevity and decay of RNA, a process critical to the development of healthy cells. The chemical modification on mRNA in question is called N6-methyladenosine (m6A). A recent study by U. Chicago scientists and collaborators reveals how the m6A modification on mRNA could affect the half-life of mRNA that in turn regulates cellular protein quantities. That discovery could provide fundamental insights into healthy functioning and disorders such as obesity, diabetes, and infertility. The m6A modification "affects a huge number of messenger RNAs in human cells, and yet we did not know its exact function," said Dr. Chuan He, professor in chemistry at U. Chicago and a recently selected investigator of the Howard Hughes Medical Institute. He, Xiao Wang and 11 co-authors from U. Chicago, University of California, San Diego, and Peking University reported their findings on m6A in the January 2, 2014 issue of Nature. RNA in human cells becomes constantly depleted as it produces proteins, an instability that is essential to biology. "Whenever a cells starts to differentiate, transform into a different type of cell, it needs to express a different set of proteins using a different set of messenger RNA," Dr. He said. "It can't be the original set." The disposal of old RNA allows for the addition of new RNA and the production of different proteins. The Nature study documents that this process is regulated by the insertion or removal of a methyl group, a chemical group commonly found in organic compounds.

10-Year Study Shows Keys to Successful Long-Term Weight Loss Maintenance

Researchers from The Miriam Hospital in Providence, Rhode Island, together with collaborators, have published one of the first studies of its kind to follow weight loss maintenance for individuals over a 10-year period. The results show that long-term weight loss maintenance is possible if individuals adhere to key health behaviors. The study is published in the January 2014 issue of the American Journal of Preventive Medicine. J. Graham Thomas, Ph.D., is the lead author on a 10-year observational study of self-reported weight loss and behavior change in nearly 3,000 participants. The participants had lost at least 30 pounds and had kept if off for at least one year when they were enrolled in the National Weight Control Registry (NWCR).vThe participants were then followed for 10 years. Dr. Thomas explains that the goal of the study was to determine how well they kept the weight off and to identify predictors of successful weight loss maintenance. Dr. Thomas says, "On average, participants maintained the majority of their weight loss over this extended follow-up period, and better success was related to continued performance of physical activity, self-weighing, low-fat diets, and avoiding overeating." Other findings from the study show that more than 87 percent of the participants were estimated to be still maintaining at least a 10 percent weight loss at years five and 10. The researchers found that a larger initial weight loss and longer duration of maintenance were associated with better long-term outcomes. Conversely, they found that decreases in physical activity, dietary restraint and self-weighing along with increases in fat intake were associated with greater weight regain. Dr. Thomas concludes, "This is one of the only studies to follow weight loss maintenance over such a long term.

January 3rd

Mating Observed for First Time in Sleeping Sickness Parasites

Caught in the act! Researchers from the University of Bristol in the UK have observed mating for the first time in the microbes responsible for African sleeping sickness. This tropical disease is caused by trypanosomes, single-celled parasites that are found in the blood of those afflicted. The Bristol team was able to see what the trypanosomes were doing inside the tsetse flies that carry the disease by using fluorescent markers. The microscopic parasites were seen twirling and gyrating together before joining up into one hybrid cell. To tell which was which, individual trypanosomes were tagged with different colors, with the result that the hybrid cells had both colours. Professor Wendy Gibson, who led the research, commented: “It’s not only bigger animals that have intricate courtship – but you need a powerful microscope to see this!” Sex matters for microbes because it enables genes to be swapped between different strains, leading to new combinations of genes. In the case of disease-causing microbes like the trypanosome, sex can potentially lead to a lot of harmful genes being combined in one strain. These new results suggest that sex is not an optional or rare part of this microbe’s life cycle, but probably happens every time two different trypanosomes find themselves together in the same tsetse fly. Trypanosomes (see image) belong to a strange group of protozoa that includes several other medically important parasites such as Leishmania, Trichomonas, and Giardia. In the past, all these microbes were thought to reproduce just by splitting in half, but now results show that they also use sex to swap genes between strains.

Loss of Function of Singe Gene Causes Type 2 Diabetes in Mice

Researchers from the University of Illinois at Chicago (UIC) College of Medicine have found that dysfunction in a single gene in mice causes fasting hyperglycemia, one of the major symptoms of type 2 diabetes. Their findings were reported online on December 30, 2013 in the journal Diabetes. If a gene called MADD (which codes for MAP kinase-activating death domain protein) is not functioning properly, insulin is not released into the bloodstream to regulate blood sugar levels, says Dr. Bellur S. Prabhakar, professor and head of microbiology and immunology at UIC and lead author of the paper. Type 2 diabetes affects roughly 8 percent of Americans and more than 366 million people worldwide. It can cause serious complications, including cardiovascular disease, kidney failure, loss of limbs and blindness. In a healthy person, beta cells in the pancreas secrete the hormone insulin in response to increases in blood glucose after eating. Insulin allows glucose to enter cells where it can be used as energy, keeping glucose levels in the blood within a narrow range. People with type 2 diabetes don’t produce enough insulin or are resistant to its effects. They must closely monitor their blood glucose throughout the day and, when medication fails, inject insulin. In previous work, Dr. Prabhakar isolated several genes from human beta cells, including MADD, which is also involved in certain cancers. Small genetic variations found among thousands of human subjects revealed that a mutation in MADD was strongly associated with type 2 diabetes in Europeans and Han Chinese. People with this mutation had high blood glucose and problems of insulin secretion – the “hallmarks of type 2 diabetes,” Dr. Prabhakar said.

January 3rd

Cleveland Clinic Researchers Create Online Colorectal Cancer Risk Calculator

Researchers at Cleveland Clinic have developed a new tool called CRC-PRO that allows physicians to quickly and accurately predict an individual's risk of colorectal cancer, as published in an open-access article in the January-February 2014 issue of the Journal of the American Board of Family Medicine. CRC-PRO, or Colorectal Cancer Predicted Risk Online, is designed to help both patients and physicians determine when screening for colorectal cancer is appropriate. Current guidelines recommend patients are screened at the age of 50. However, with this new tool, physicians will be better able to identify who is truly at risk and when screenings for patients are necessary. To develop the calculator, the researchers – led by Brian Wells, M.D., Ph.D., of the Department of Quantitative Health Sciences in Cleveland Clinic's Lerner Research Institute – analyzed data on over 180,000 patients from a longitudinal study conducted at the University of Hawaii. Patients were followed for up to 11.5 years to determine which factors were highly associated with the development of colorectal cancer. "Creating a risk calculator that includes multiple risk factors offers clinicians a means to more accurately predict risk than the simple age-based cutoffs currently used in clinical practice," said Dr. Wells. "Clinicians could decide to screen high-risk patients earlier than age 50, while delaying or foregoing screening in low-risk individuals." Dr. Wells and his colleagues hope that their new, user-friendly calculator will help improve the efficiency of colorectal cancer screenings. They also believe prediction tools like this can help lower healthcare costs by cutting down on unnecessary testing. The Multiethnic Cohort Study comprised a diverse ethnic population.

Deletion Increases Milk Production, Decreases Fertility in Dairy Cattle

Scientists have found a genomic deletion that affects fertility and milk yield in dairy cattle at the same time. The discovery can help explain a dilemma in dairy cattle breeding: the negative correlation between fertility and milk production. The work was published online on January 2, 2014 in the open-access journal PLOS GENETICS. For the past many years, milk yield in Scandinavian dairy cattle has gone in one clear direction: up. This has been due to targeted breeding programs and modern breeding methods. Despite putting large weight on the breeding goal in Nordic countries, almost no improvement is achieved for fertility. It now seems that this unfavourable correlation between milk yield and fertility is partially affected by a deletion of a simple gene sequence. The presence and effects of this mutation have recently been discovered by scientists from Aarhus University, the University of Liège, and MTT Agrifood Research Finland, in collaboration with the Danish Agricultural Advisory Service and the Nordic Cattle Genetic Evaluation. Scientists, farmers, and advisors have generally assumed that the reduction in fertility is primarily due to the negative energy balance of high-producing cows at the peak of their lactation, but now the scientists have also found a genetic explanation. “We have discovered a deletion encompassing four genes as the causative variant and shown that the deletion is a recessive embryonically lethal mutation,” explains Dr. Goutam Sahana. This means that the calves die while they are still embryos and are aborted or reported as insemination failure. The fact that the mutation is recessive means that both parents must carry it and pass the genes on to their calf for the calf to be affected.