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.
Monday, November 13, 2017
NIH scientists improve efficiency, speed, and resolution of optical microscopy.
Researchers from the National Institutes of Health and the University of Chicago improved the speed, resolution, and light efficiency of an optical microscope by switching from a conventional glass coverslip to a reflective, mirrored coverslip and applying new computer algorithms to process the resulting data.
Hari Shroff, Ph.D., chief of the National Institute of Biomedical Imaging and Bioengineering’s lab section on High Resolution Optical Imaging (HROI), and his team have spent the last few years developing optical microscopes that produce high resolution images at very high speed. After his lab develops these new microscopes, they release the plans and software for free, so any researcher can replicate the advances made at NIH.
An image of a zebrafish eye collected by a super resolution microscope that also uses adaptive optics to increase efficacy.
Monday, November 13, 2017
Obesity during pregnancy — independent of its health consequences such as diabetes — may account for the higher risk of giving birth to an atypically large infant, according to researchers at the National Institutes of Health. Their study appears in JAMA Pediatrics.
“Our results underscore the importance of attaining a healthy body weight before pregnancy,” said the study’s lead author, Cuilin Zhang, M.D., Ph.D., a researcher in the Division of Intramural Population Health Research at NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development. “They also suggest that clinicians should carefully monitor the pregnancies of all obese women, regardless of whether or not they have obesity-related health conditions.”
Wednesday, November 8, 2017
River blindness, or onchocerciasis, is a disease caused by a parasitic worm found primarily in Africa. The worm (Onchocerca volvulus) is transmitted to humans as immature larvae through bites of infected black flies. Symptoms of infection include intense itching and skin nodules. Left untreated, infections in the eye can cause vision impairment that leads to blindness. Mass distribution of ivermectin is currently used to treat onchocerciasis. However, this treatment can be fatal when a person has high blood levels of another filarial worm, Loa loa. In a paper published in the New England Journal of Medicine, scientists from the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, and other organizations describe how a cell phone-based videomicroscope can provide fast and effective testing for L. loa parasites in the blood, allowing these individuals to be protected from the adverse effects of ivermectin.