Heating pads may lower blood pressure in people with high blood pressure when lying down

In people with supine hypertension due to autonomic failure, a condition that increases blood pressure when lying down, overnight heat therapy significantly decreased systolic blood pressure compared to a placebo. Heat therapy may be an innovative, non-pharmacologic approach to treat the overnight high blood pressure in these patients. Source

Deducing the scale of tsunamis from the ’roundness’ of deposited gravel

Scientists have found a link between the ’roundness’ distribution of tsunami deposits and how far tsunamis reach inland. They sampled the ’roundness’ of gravel from different tsunamis in Koyadori, Japan, and found a common, abrupt change in composition approximately 40% of the ‘inundation distance’ from the shoreline, regardless of tsunami magnitude. Estimates of ancient tsunami size from geological deposits may help inform effective disaster mitigation. Source

Bioprinting complex living tissue in just a few seconds

Tissue engineers create artificial organs and tissues that can be used to develop and test new drugs, repair damaged tissue and even replace entire organs in the human body. However, current fabrication methods limit their ability to produce free-form shapes and achieve high cell viability.

Researchers at the Laboratory of Applied Photonics Devices (LAPD), in EPFL’s School of Engineering, working with colleagues from Utrecht University, have come up with an optical technique that takes just a few seconds to sculpt complex tissue shapes in a biocompatible hydrogel containing stem cells. The resulting tissue can then be vascularized by adding endothelial cells.

The team describes this high-resolution printing method in an article appearing in Advanced Materials. The technique will change the way cellular engineering specialists work, allowing them to create a new breed of personalized, functional bioprinted organs.

Printing a femur or a meniscus

The technique is called volumetric bioprinting. To create tissue, the researchers project a laser down a spinning tube filled with a stem-cell-laden hydrogel. They shape the tissue by focusing the energy from the light at specific locations, which then solidify. After just a few seconds, a complex 3D shape appears, suspended in the gel. The stem cells in the hydrogel are largely unaffected by this process. The researchers then introduce endothelial cells to vascularize the tissue.

The researchers have shown that it’s possible to create a tissue construct measuring several centimeters, which is a clinically useful size. Examples of their work include a valve similar to a heart valve, a meniscus and a complex-shaped part of the femur. They were also able to build interlocking structures.

“Unlike conventional bioprinting — a slow, layer-by-layer process — our technique is fast and offers greater design freedom without jeopardizing the cells’ viability,” says Damien Loterie, an LAPD researcher and one of the study’s coauthors.

Replicating the human body

The researchers’ work is a real game changer. “The characteristics of human tissue depend to a large extent on a highly sophisticated extracellular structure, and the ability to replicate this complexity could lead to a number of real clinical applications,” says Paul Delrot, another coauthor. Using this technique, labs could mass-produce artificial tissues or organs at unprecedented speed. This sort of replicability is essential when it comes to testing new drugs in vitro, and it could help obviate the need for animal testing — a clear ethical advantage as well as a way of reducing costs.

“This is just the beginning. We believe that our method is inherently scalable towards mass fabrication and could be used to produce a wide range of cellular tissue models, not to mention medical devices and personalized implants,” says Christophe Moser, the head of the LAPD.

The researchers plan to market their groundbreaking technique through a spin-off.

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Materials provided by Ecole Polytechnique Fédérale de Lausanne. Original written by Laure-Anne Pessina. Note: Content may be edited for style and length.

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Vehicle exhaust pollutants linked to near doubling in risk of common eye condition

Long term exposure to pollutants from vehicle exhaust is linked to a heightened risk of the common eye condition age-related macular degeneration, or AMD for short, suggests research published online in the Journal of Investigative Medicine.

Exposure to the highest levels of air pollutants was associated with an almost doubling in risk among those aged 50 and older, the findings show.

AMD is a neurodegenerative condition that affects the middle part of the retina, known as the macula. It is one of the most common causes of poor vision in older people, and is most likely caused by an interplay between genetic and environmental risk factors.

Long term exposure to air pollution has been linked to a heightened risk of several conditions, including respiratory and cardiovascular diseases. But less is known about its potential effects on eye health.

To explore this further, the Taiwanese researchers analysed national health insurance and air quality data from 1998 to 2010 to see if there might be a link between long term exposure to the pollutants nitrogen dioxide (NO?) and carbon monoxide (CO) and a heightened risk of AMD.

As the condition is more common among older age groups, the researchers focused only on 39,819 people aged 50 and above, most of whom lived in either highly (30%) or moderately (32.5%) urbanised areas.

Because there are seasonal variations in air pollutant levels, the researchers calculated an average annual exposure, which was categorised into four different levels.

During the monitoring period, 1442 people developed AMD.

After taking account of potentially influential factors, such as age, sex, household income, and underlying illnesses, those with the highest level of exposure to NO? (more than 9825.5 ppb) were nearly twice (91%) as likely to develop AMD as those exposed to the lowest level (less than 6563.2 ppb).

And people who were exposed to the highest level of CO (more than 297.1 ppm) were 84% more likely to develop AMD than those exposed to the lowest level (less than 195.7 ppm).

The highest rate (5.8%) of newly diagnosed AMD was among people living in the area with the highest level of CO exposure.

This is an observational study, and as such, can’t establish cause. And the authors emphasise that the data didn’t include information on other risk factors, such as smoking, genetics, and inflammation.

This is the first study of its kind to “demonstrate a significant association between AMD and high levels of ambient NO? and CO,” they write.

Recent research has implicated NO? in cardiovascular and neurological ill health, and as the retina is part of the central nervous system, there is a plausible biological explanation for its vulnerability to this pollutant, they add.

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Materials provided by BMJ. Note: Content may be edited for style and length.

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Shedding light on how the human eye perceives brightness

Japanese scientists are shedding new light on the importance of light-sensing cells in the retina that process visual information. The researchers isolated the functions of melanopsin cells and demonstrated their crucial role in the perception of visual environment. This ushers in a new understanding of the biology of the eye and how visual information is processed.

The findings could contribute to more effective therapies for complications that relate to the eye. They can also serve as the basis for developing lighting and display systems.

The research was published in Scientific Reports on May 20th, 2019.

The back of the human eye is lined with the retina, a layer of various types of cells, called photoreceptors, that respond to different amounts of light. The cells that process a lot of light are called cones and those that process lower levels of light are named rods.

Up until recently, researchers have thought that when light struck the retina, rods and cones were the only two kinds of cells that react. Recent discoveries have revealed an entirely new type of cells, called intrinsically photosensitive retinal ganglion cells (ipRGCs). Unlike rods and cones, ipRGCs contain melanopsin, a photopigment that is sensitive to light. While it has been established that ipRGCs are involved in keeping the brain’s internal clock in sync with changes in daylight, their importance in the detection of the amount of light had not yet been well understood.

“Until now, the role of retinal melanopsin cells and how they contribute to the perception of the brightness of light have been unclear,” said Katsunori Okajima, a professor at the Faculty of Environment and Information Sciences, Yokohama National University and one of the authors of the study.

“We’ve found that melanopsin plays a crucial role on the human ability to see how well-lit the environment is. These findings are redefining the conventional system of light detection that so far has only taken into consideration two variables, namely brightness and the amount of incoming light. Our results suggest that brightness perception should rely on a third variable — the intensity of a stimulus that targets melanopsin.”

In the study, the authors showed how cones and melanopsin combine to allow the perception of brightness. In order to better assess the contribution of melanopsin to the detection of light, the melanopsin’s signals were isolated from cones and rods. This separation allowed for more accurate observation of the melanopsin signal alone. Visual stimuli were carefully designed and positioned in order to specifically stimulate the light-sensitive chemical. Also, the researchers used tracking software to measure study participants’ pupil diameters under each visual stimulus. This served as a way to determine the relationship between brightness perception and the actual visual stimulus intensity on the retina.

The researchers were able to show that the varying brightness levels of an image that was perceived is a sum of the melanopsin response and the response that is generated by the cones. The former is a linear readout and the latter is not. The results also show that melanopsin is not a minor contributor in brightness perception. Rather, it is a crucial player in brightness perception.

This work was supported by the Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research (Grant Numbers 15H05926 and 18H04111).

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Materials provided by Yokohama National University. Note: Content may be edited for style and length.

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‘Silent’ strokes common after surgery, linked to cognitive decline

Canadian researchers have discovered that covert — or ‘silent’ — strokes are common in seniors after they have elective, non-cardiac surgery and double their risk of cognitive decline one year later.

While an overt stroke causes obvious symptoms, such as weakness in one arm or speech problems that last more than a day, a covert stroke is not obvious except on brain scans, such as MRI. Each year, approximately 0.5 per cent of the 50 million people age 65 years or greater worldwide who have major, non-cardiac surgery will suffer an overt stroke, but until now little was known about the incidence or impacts of silent stroke after surgery.

The results of the NeuroVISION study were published today in The Lancet.

“We’ve found that ‘silent’ covert strokes are actually more common than overt strokes in people aged 65 or older who have surgery,” said Dr. PJ Devereaux, co-principal investigator of the NeuroVISION study. Dr. Devereaux is a cardiologist at Hamilton Health Sciences (HHS), professor in the departments of health research methods, evidence, and impact, and medicine at McMaster University, and a senior scientist at the Population Health Research Institute of McMaster University and HHS.

Dr. Devereaux and his team found that one in 14 people over age 65 who had elective, non-cardiac surgery had a silent stroke, suggesting that as many as three million people in this age category globally suffer a covert stroke after surgery each year.

NeuroVISION involved 1,114 patients aged 65 years and older from 12 centres in North and South America, Asia, New Zealand, and Europe. All patients received an MRI within nine days of their surgery to look for imaging evidence of silent stroke. The research team followed patients for one year after their surgery to assess their cognitive capabilities. They found that people who had a silent stroke after surgery were more likely to experience cognitive decline, perioperative delirium, overt stroke or transient ischaemic attack within one year, compared to patients who did not have a silent stroke.

“Over the last century, surgery has greatly improved the health and the quality of life of patients around the world,” said Dr. Marko Mrkobrada, an associate professor of medicine at University of Western Ontario and co-principal investigator for the NeuroVISION study. “Surgeons are now able to operate on older and sicker patients thanks to improvements in surgical and anesthetic techniques. Despite the benefits of surgery, we also need to understand the risks.”

“Vascular brain injuries, both overt and covert, are more frequently being detected, recognized and prevented through research funded by our Institute and CIHR,” says Dr. Brian Rowe, scientific director of the Institute of Circulatory and Respiratory Health, Canadian Institutes of Health Research (CIHR). “The NeuroVISION Study provides important insights into the development of vascular brain injury after surgery, and adds to the mounting evidence of the importance of vascular health on cognitive decline. The results of NeuroVISION are important and represent a meaningful discovery that will facilitate tackling the issue of cognitive decline after surgery.”

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Materials provided by McMaster University. Note: Content may be edited for style and length.

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