NIH Scientists Combine Technologies to View the Retina in Unprecedented Detail
By combining two imaging modalities—adaptive optics and angiography—investigators at the National Eye Institute can see live neurons, epithelial cells and blood vessels deep in the eye’s light-sensing retina. Resolving these tissues and cells in the outermost region of the retina in such unprecedented detail promises to transform the detection and treatment of diseases such as age-related macular degeneration, a leading cause of blindness among the elderly. The paper was published online in Communications Biology.
“For studying diseases, there’s no substitute for watching live cells interact,” said Dr. Johnny Tam, Stadtman investigator in NEI’s clinical and translational imaging unit and lead author of the paper. “However, conventional technologies are limited in their ability to show such detail.”
Biopsied and postmortem tissues are commonly used to study disease at the cellular level, but they are less than ideal for watching subtle changes that occur as a disease progresses over time. Technologies for noninvasively imaging retinal tissues are hampered by distortions to light as it passes through the cornea, lens and the gel-like vitreous in the center of the eye.
Tam and his team turned to adaptive optics to address this distortion problem. The technique improves the resolution of optical systems by using deformable mirrors and computer-driven algorithms to compensate for light distortions. Widely utilized in large ground-based space telescopes to correct distortions to light traveling through the atmosphere, adaptive optics began being used in ophthalmology in the mid-1990s.
The NEI researchers combined adaptive optics with indocyanine green angiography, an imaging technique commonly used in eye clinics that uses an injectable dye and cameras to show vessel structures and the movement of fluid within those structures.NIH Scientists Illuminate Causes of Hepatitis B Virus-Associated Acute Liver Failure
NIH scientists and their collaborators found that hepatitis B virus (HBV)- associated acute liver failure (ALF)—a rare condition that can turn fatal within days without liver transplantation—results from an uncommon encounter between a highly mutated HBV variant and an unusual immune response in the patient’s liver that is mainly sustained by antibody-producing B cells.
By applying state-of-the-art technologies, the researchers discovered important new mechanisms about the disease by examining liver samples taken from four patients who developed HBV-ALF. HBV-ALF is one of the most dramatic clinical syndromes in medicine, according to the research team, but so rare that samples of this type are seldom available for study.
Scientists from NIAID led the project with colleagues from two Italian universities. Their study is published in Proceedings of the National Academy of Sciences.
The investigators used advanced gene sequencing and tissue and cell analysis technologies to determine specific molecular events occurring at the site where HBV replicates and damages liver tissue. They identified processes that are distinct to HBV-ALF cases compared with cases of classic acute HBV infection. Some of these unique events involve a highly mutated virus antigen, the HBV core antigen. The scientists believe that this antigen plays a key role in disease development because it interacts with specific antibodies that are—unusually, they say—already present in these patients.
Due to ethical reasons in obtaining liver tissues from patients with classic acute HBV, for their comparison study the scientists used archived liver specimens from two chimpanzees with acute HBV that had been studied many years earlier. They found the mechanism of acute HBV disease to be completely different from that of ALF.More Adults, Children Use Yoga, Meditation
Over the past 5 years, more Americans of all ages are rolling out their yoga mats and meditating. A large nationally representative survey shows that the number of American adults and children using yoga and meditation has significantly increased over previous years and that use of chiropractic care has increased modestly for adults and held steady for children.
The complementary health questionnaire was developed by the National Center for Complementary and Integrative Health and by the Centers for Disease Control and Prevention’s National Center for Health Statistics. The complementary health questionnaire is administered every 5 years as part of the National Health Interview Survey (NHIS), an annual study in which thousands of Americans are interviewed about their health- and illness-related experiences. To identify trends in Americans’ use of specific practices, 2017 survey data were compared with a version of the survey fielded in 2012.
“The 2017 NHIS survey is the most current and reliable source of information on the use of specific complementary health approaches by U.S. adults and children,” said Dr. David Shurtleff, acting director of NCCIH. “The survey data suggest that more people are turning to mind and body approaches than ever before, and the research we support at NCCIH is helping to determine the impact of those approaches on health.”
Survey highlights for adults: