Insight into jumping genes
Duke University scientists in the U.S. have identified a mechanism in the molecular machinery of the cell that could help explain how neurons begin to falter in the initial stages of Alzheimer’s, even before amyloid clumps appear.
This rethinking of the Alzheimer’s process centres on human genes critical for the healthy functioning of mitochondria, the energy factories of the cell, which are riddled with mobile chunks of DNA called Alu elements.
If these “jumping genes” lose their normal controls as a person ages, they could start to wreak havoc on the machinery that supplies energy to brain cells, leading to a loss of neurons and ultimately dementia, the researchers say.
And if this “Alu neurodegeneration hypothesis” holds up, it could help identify people at risk sooner before they develop symptoms or point to new ways to delay onset or slow progression of the disease, says study co-author Peter Larsen, senior research scientist in biology professor Anne Yoder’s lab at Duke.
Boosting deep sleep
Gentle sound stimulation, such as the rush of a waterfall, synchronised to the rhythm of brain waves significantly enhances deep sleep in older adults and improves their ability to recall words, reports a new Northwestern Medicine study. Deep sleep is critical for memory consolidation. But when middle age starts, deep sleep decreases substantially, which scientists believe contributes to memory loss in aging.
The sound stimulation significantly enhanced deep sleep in participants and their scores on a memory test.
“This is an innovative, simple and safe non-medication approach that may help improve brain health,” says senior author Dr. Phyllis Zee, professor of neurology at Chicago’s Northwestern University Feinberg School of Medicine and a Northwestern Medicine sleep specialist. “This is a potential tool for enhancing memory in older populations and attenuating normal age-related memory decline.” The study was published on March 8 in Frontiers in Human Neuroscience.
In the study, 13 participants 60 and older received one night of acoustic stimulation and one night of sham stimulation. The sham stimulation procedure was identical to the acoustic one, but participants did not hear any noise during sleep. For both the sham and acoustic stimulation sessions, the individuals took a memory test at night and again the next morning. ‘Recall ability’ after the sham stimulation generally improved in the morning test by a few percent.
A new find, in amber
A research team led by researchers from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS) has found a new morphologically specialised beetle from mid-Cretaceous Burmese amber, some 99 million years ago, shedding new light on the predator-prey associations in the late Mesozoic terrestrial ecosystem. The findings have been published in the British nature research journal, Scientific Reports.
Insects exhibit various morphological specialisations specific to particular behaviours, and these permit the reconstruction of palaeobiological traits. Dr. Cai Chenyang at NIGPAS and Dr. Yin Ziwei at the Shanghai Normal University discovered three exceptionally well-preserved fossils of the highly specialised ant-like stone beetles (Staphylinidae, Scydmaeninae).
These fossils have been named Cascomastigus monstrabilis YIN and CAI, 2017. These early beetles display morphological modifications on the antennae unknown among living ant-like stone beetles and associated with predation on springtails (Collembola), a widespread and abundant group of significantly greater geological age. Cascomastigus has an extremely large body size, elongate clubbed maxillary palpi, toothed mandibles, and, more importantly, slender and highly modified antennae that functioned as an antennal setal trap. Such an antennal modification is analogous to that of the modern ground beetle genus Loricera (Carabidae, Loricerinae), a group possessing a specialised antennal setal trap exclusively for the capture of springtails. The beetles are the world’s earliest known insects to eat springtails, an insect-like food resource for litter-dwelling beetles.
Productivity catches a cold
Depressed patients with chronic rhinosinusitis (CRS) are more likely to miss days of work or school than those without depression symptoms, according to the results of a new study led by the Sinus Center at Massachusetts Eye and Ear, a teaching hospital of Harvard Medical School and home to the world’s largest vision and hearing research centres. The findings, published online in Annals of Allergy, Asthma and Immunology, identify depression symptoms as the primary driver of lost days of productivity in patients with CRS, paving the way for more individualised therapy to improve overall quality of life in these patients.
“In this study, we found that of all symptoms related to CRS — sinus, nasal or otherwise — the severity of depressed mood and depression symptomatology was the predominant factor associated with how often our CRS patients missed work or school due to their CRS,” says senior author Ahmad R. Sedaghat, M.D., PhD., a sinus surgeon at Mass. Eye and Ear and assistant professor of otolaryngology at Harvard Medical School. “The severity of even symptoms most typically related to CRS, such as nasal congestion, was not associated with how often our patients missed work or school due to their CRS.”
One of the more prevalent chronic illnesses in the United States, CRS has been known to cause significant quality of life detriments to affected patients, who often cannot breathe or sleep easily due to obstructed nasal and sinus passages.
The researchers previously identified four categories of symptoms that dominate CRS — disturbances of sleep, nasal obstruction, ear and facial pain and emotional function. In subsequent studies, they showed that disturbed sleep and ear/facial pain are most associated with overall poorer quality of life.
A sudden death gene
Researchers from Canada, South Africa and Italy have identified a new gene that can lead to sudden death among young people and athletes. Called CDH2, it causes arrhythmogenic right ventricle cardiomyopathy (ARVC), which is a genetic disorder that predisposes patients to cardiac arrest and is a major cause of unexpected death in seemingly healthy young people.
Inherited forms of cardiomyopathy often cause sudden cardiac arrest death in young people under the age of 35. In ARVC, the heart tissue is replaced by fatty and fibrous tissue. This process encourages the development of cardiac arrhythmias such as tachycardia and ventricular fibrillation, which cause loss of consciousness and cardiac arrest. In the case of ventricular fibrillation, without a ready electrical defibrillation, it causes sudden death in a few minutes.
The discovery, published in Circulation: Cardiovascular Genetics, is the result of international collaboration that began 15 years ago.