Tuesday, December 19, 2017
Researchers find target to protect hearing during chemotherapy treatment.
Scientists have found a new way to explain the hearing loss caused by cisplatin, a powerful drug used to treat many forms of cancer. Using a highly sensitive technique to measure and map cisplatin in mouse and human inner ear tissues, researchers found that forms of cisplatin build up in the inner ear. They also found a region in the inner ear that could be targeted for efforts to prevent hearing loss from cisplatin. The study is published in Nature Communications, and was supported by the National Institute on Deafness and other Communications Disorders (NIDCD), part of the National Institutes of Health.
Cisplatin and similar platinum-based drugs are prescribed for an estimated 10 to 20 percent of all cancer patients. The NIH’s National Cancer Institute supported research that led to the 1965 discovery of cisplatin and continued development leading to its success as an essential weapon in the battle against cancer. The drugs cause permanent hearing loss in 40 to 80 percent of adult patients and at least half of children who receive the drug. The new findings help explain why cisplatin is so toxic to the inner ear, and why hearing loss gets worse after each treatment, can occur long after treatment, and is more severe in children than adults.
Cisplatin (appearing in green) in the stria vascularis of a mouse inner ear.
Thursday, December 14, 2017
Scientists have identified differences in a group of genes they say might help explain why some people need a lot more sleep — and others less — than most. The study, conducted using fruit fly populations bred to model natural variations in human sleep patterns, provides new clues to how genes for sleep duration are linked to a wide variety of biological processes.
Researchers say a better understanding of these processes could lead to new ways to treat sleep disorders such as insomnia and narcolepsy. Led by scientists with the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of Health, the study will be published on Dec. 14 in PLOS Genetics.
“This study is an important step toward solving one of the biggest mysteries in biology: the need to sleep,” says study leader Susan Harbison, Ph.D., an investigator in the Laboratory of Systems Genetics at NHLBI. “The involvement of highly diverse biological processes in sleep duration may help explain why the purpose of sleep has been so elusive.”
Graph showing sleep duration (in minutes) of wild fruit flies—long sleepers, normal sleepers, and short sleepers—artificially bred across 13 generations.
Monday, December 4, 2017
Vaccine developed by NIH scientists shows promise in Phase 1 testing.
Results from two Phase 1 clinical trials show an experimental Zika vaccine developed by government scientists at the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, is safe and induces an immune response in healthy adults. The findings will be published on Dec. 4 in The Lancet. NIAID is currently leading an international effort to evaluate the investigational vaccine in a Phase 2/2b safety and efficacy trial.
“Following early reports that Zika infection during pregnancy can lead to birth defects, NIAID scientists rapidly created one of the first investigational Zika vaccines using a DNA-based platform and began initial studies in healthy adults less than one year later,” said NIAID Director Anthony S. Fauci, M.D. “NIAID has begun Phase 2 testing of this candidate to determine if it can prevent Zika virus infection, and the promising Phase 1 data published today support its continued development.”
Investigators from NIAID’s Vaccine Research Center (VRC) and Laboratory of Viral Diseases, part of the Division of Intramural Research, developed the investigational vaccine, which includes a small, circular piece of DNA called a plasmid. Scientists inserted genes into the plasmid that encode two proteins found on the surface of the Zika virus. After the vaccine is injected into muscle, the body produces proteins that assemble into particles that mimic the Zika virus and trigger the body to mount an immune response.
Thursday, November 30, 2017
Allergens are widespread, but highly variable in U.S. homes, according to the nation’s largest indoor allergen study to date. Researchers from the National Institutes of Health report that over 90 percent of homes had three or more detectable allergens, and 73 percent of homes had at least one allergen at elevated levels. The findings were published November 30 in the Journal of Allergy and Clinical Immunology.
“Elevated allergen levels can exacerbate symptoms in people who suffer from asthma and allergies, so it is crucial to understand the factors that contribute,” said Darryl Zeldin, M.D., senior author and scientific director at the National Institute of Environmental Health Sciences (NIEHS), which is part of NIH.
Using data from the 2005-2006 National Health and Nutrition Examination Survey (NHANES), the researchers studied levels of eight common allergens – cat, dog, cockroach, mouse, rat, mold, and two types of dust mite allergens – in the bedrooms of nearly 7,000 U.S. homes.
Factors contributing to elevated bedroom allergen levels include presence of pets and pests, type of housing, and living in rural areas. Individual allergens vary by geographic area.
Wednesday, November 29, 2017
NIH-supported study provides evidence for implementing approach broadly.
A study published today in the New England Journal of Medicine provides real-world evidence that implementing a combination of proven HIV prevention measures across communities can substantially reduce new HIV infections in a population.
Investigators found that HIV incidence dropped by 42 percent among nearly 18,000 people in Rakai District, Uganda, during a seven-year period in which the rates of HIV treatment and voluntary medical male circumcision increased significantly.
The HIV prevention strategy whose impact was observed in the study is based on earlier findings by the National Institutes of Health and others demonstrating the protective effect of voluntary medical male circumcisionfor HIV-uninfected men and of HIV-suppressing antiretroviral therapy (ART) for halting sexual transmission of the virus to uninfected partners. The strategy is also based on studies showing that changes in sexual behavior, such as having only one sexual partner, can help prevent HIV infection.
A research assistant draws blood for HIV testing from a participant in the Rakai Community Cohort Study. Credit: Rakai Health Sciences Program
Wednesday, November 29, 2017
Population study finds higher risk of psychiatric hospitalization among daughters of female evacuees.
Mental illness associated with early childhood adversity may be passed from generation to generation, according to a study of adults whose parents evacuated Finland as children during World War II. The study was conducted by researchers at the National Institutes of Health, Uppsala University in Sweden, and Helsinki University in Finland. It appears in JAMA Psychiatry.
The research team found that daughters of female evacuees had the same high risk for mental health disorders as their mothers, even though they did not experience the same adversity. The study could not determine why the higher risk for mental illness persisted across generations. Possible explanations include changes in the evacuees’ parenting behavior stemming from their childhood experience or epigenetic changes — chemical alterations in gene expression, without any changes to underlying DNA.
“Many studies have shown that traumatic exposures during pregnancy can have negative effects on offspring,” said study author Stephen Gilman, Sc.D., of the Division of Intramural Population Health Research at the Eunice Kennedy Shriver National Institute of Child Health and Human Development. “Here, we found evidence that a mother’s childhood traumatic exposure — in this case separation from family members during war — may have long-lasting health consequences for her daughters.”
Tuesday, November 28, 2017
Tick bites likely lead to the unusual, misdiagnosed allergy.
While rare, some people experience recurrent episodes of anaphylaxis — a life-threatening allergic reaction that causes symptoms such as the constriction of airways and a dangerous drop in blood pressure — for which the triggers are never identified. Recently, researchers at the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, found that some patients’ seemingly inexplicable anaphylaxis was actually caused by an uncommon allergy to a molecule found naturally in red meat. They note that the allergy, which is linked to a history of a specific type of tick bite, may be difficult for patients and health care teams to identify.
As the researchers describe in their article published in Allergy, six of the 70 study participants evaluated for unexplained frequent anaphylaxis tested positive for an allergy to galactose-α-1,3-galactose, or alpha-gal, a sugar molecule found in beef, pork, lamb and other red meats. The six adult male participants all had IgE antibodies — immune proteins associated with allergy — to alpha-gal in their blood. After implementing diets free of red meat, none of them experienced anaphylaxis in the 18 months to 3 years during which they were followed.
An adult female Lone Star tick climbs on a plant. Bites from the juvenile form of this species, sometimes called seed ticks, are linked to the development of red meat allergy.
Wednesday, November 22, 2017
The brain of one patient who died from sporadic Creutzfeldt-Jacob disease (sCJD) appears nearly identical to the brain of a mouse inoculated with infectious prions taken from the skin of patients who died from sCJD.
National Institutes of Health scientists and collaborators at Case Western Reserve University School of Medicine, Cleveland, have detected abnormal prion protein in the skin of nearly two dozen people who died from Creutzfeldt-Jakob disease (CJD). The scientists also exposed a dozen healthy mice to skin extracts from two of the CJD patients, and all developed prion disease. The study results, published in Science Translational Medicine, raise questions about the possible transmissibility of prion diseases via medical procedures involving skin, and whether skin samples might be used to detect prion disease. Researchers from NIH’s National Institute of Allergy and Infectious Diseases (NIAID) were co-leaders of the study, which included multiple collaborating groups. They stress that the prion-seeding potential found in skin tissue is significantly less than what they have found in studies using brain tissue.
CJD is an incurable — and ultimately fatal — transmissible, neurodegenerative disorder in the family of prion diseases. Prion diseases originate when normally harmless prion protein molecules become abnormal and gather in clusters and filaments in the human body and brain. The reasons for this process are not fully understood. The accumulation of these clusters has been associated with tissue damage that leaves sponge-like holes in the brain. Human prion diseases include fatal insomnia; kuru; Gerstmann-Straussler-Scheinker syndrome; and variant, familial and sporadic CJD. Sporadic CJD is the most common human prion disease, affecting about one in one million people annually worldwide. Other prion diseases include scrapie in sheep; chronic wasting disease in deer, elk and moose; and bovine spongiform encephalopathy, or mad cow disease, in cattle.
Friday, November 17, 2017
Multi-step screening process leads to molecule that may protect brain cells.
In the fight against brain damage caused by stroke, researchers have turned to an unlikely source of inspiration: hibernating ground squirrels.
While the animals’ brains experience dramatically reduced blood flow during hibernation, just like human patients after a certain type of stroke, the squirrels emerge from their extended naps suffering no ill effects. Now, a team of NIH-funded scientists has identified a potential drug that could grant the same resilience to the brains of ischemic stroke patients by mimicking the cellular changes that protect the brains of those animals.
An ischemic stroke occurs when a clot cuts off blood flow to part of the brain, depriving those cells of oxygen and nutrients like the blood sugar glucose that they need to survive. Nearly 800,000 Americans experience a stroke every year and 87 percent of those are ischemic strokes.
Currently, the only way to minimize stroke-induced cell death is to remove the clot as soon as possible. A treatment to help brain cells survive a stroke-induced lack of oxygen and glucose could dramatically improve patient outcomes, but no such neuroprotective agents for stroke patients exist.
Recently, researchers led by John Hallenbeck, M.D., an NINDS senior investigator and co-senior author of the study, found that a cellular process called SUMOylation goes into overdrive in a certain species of ground squirrel during hibernation. Dr. Hallenbeck suspected this was how the animals’ brains survived the reduced blood flow caused by hibernation, and subsequent experiments in cells and mice confirmed his suspicions.
Thursday, November 16, 2017
Ozone is a highly reactive form of oxygen that is a primary constituent of urban smog.
Exposure to common air pollutants, such as ozone and fine particles, may increase the risk of early pregnancy loss, according to a study conducted by the National Institutes of Health and led by Pauline Mendola, Ph.D., an investigator at NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). The study appears in the journal Fertility and Sterility.
Ozone is a highly reactive form of oxygen that is a primary constituent of urban smog. Researchers followed 501 couples attempting to conceive between 2005 and 2009 in Michigan and Texas. The investigators estimated the couples’ exposures to ozone based on pollution levels in their residential communities. Of the 343 couples who achieved pregnancy, 97 (28 percent) experienced an early pregnancy loss — all before 18 weeks. Couples with higher exposure to ozone were 12 percent more likely to experience an early pregnancy loss, whereas couples exposed to particulate matter(link is external) (small particles and droplets in the air) were 13 percent more likely to experience a loss.