Tag: 8/2/23

Categories : COVID HospitalsTags :

Ceiling Vents Above COVID Patient Beds Provide Optimal Protection for HCWs

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Source: Martha Dominguez de Gouveia on Unsplash

Researchers have modelled the transmission of SARS-CoV-2-containing aerosol particles within an isolation room, and found the optimal layout to reduce the exposure risk for health care workers. In Physics of Fluids, Wu et al. share their findings and guidance for isolation rooms. Their work focuses on the location of the room’s air extractor (air outlet) and filtration rates, the location of the patient’s bed, and the health and safety of the health care workers (HCWs) within the area.

The researchers modelled an isolation room at the Royal Brompton Hospital in London, with the aim of finding out the optimal room layout to reduce the risk of infection for health care staff.

“We modelled the virus transport and spreading processes and considered the effect of the temperature and humidity on the virus decay,” said Fangxin Fang, of Imperial College London. “We also modelled fluid and turbulence dynamics in our study, and explored the spatial distribution of virus, velocity field, and humidity under different air exchange rates and extractor locations.”

They discovered that the area of highest risk of infection is above a patient’s bed at a height of 0.7 to 2 metres, where the highest concentration of SARS-CoV-2 virus is found. After the virus is expelled from a patient’s mouth, it gets driven vertically by buoyancy and wind forces within the room.

Based on the group’s findings, the optimal layout for an isolation room to minimise infection risk is to use a ceiling extractor with an air exchange rate of 10 air changes per hour. The study focused on an isolation room within a hospital and its numerical results are limited due to the omission of droplet evaporation and particle matters, the researchers point out.

Now, the group plans to include evaporation and particle processes in models of a standard hospital patient room, intensive care unit, and waiting room.

“Further work will also focus on artificial intelligence-based surrogate modelling for rapid simulations, uncertainty analysis, and optimal control of ventilation systems as well as efficient energy use,” said Fang.

Source: American Institute of Physics

Categories : Diet and Nutrition GastrointestinalTags :

A High-fat Diet Might be Useful in Expelling Intestinal Worms

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Photo by Jonathan Borba on Unsplash

Scientists have discovered that a high-fat diet might actually have a benefit in some cases: it allows the immune system to eliminate a parasitic worm which is a major cause of death and illness in the developing world. Their findings appear in the journal Mucosal Immunology.

Parasitic worms affect up to a billion people, particularly in developing nations with poor sanitation. One of these parasites known as “whipworm” can cause long lasting infections in the large intestine.

Lead author Dr Evelyn Funjika, formerly at Manchester and now at the University of Zambia, said: “Just like the UK, the cheapest diets are often high in fat and at-risk communities to whipworm are increasingly utilising these cheap diets. Therefore, how worm infection and western diets interact is a key unknown for developing nations.

“In order to be able to study how nutrition affects parasite worm infection, we have been using a mouse model, Trichuris muris, closely related to the human whipworm Trichuris trichiura and seeing how a high-fat diet impacts immunity.”

It has been previously shown that immune responses which expel the parasite rely on white blood cells called T-helper 2 cells, specialised for eliminating gastrointestinal parasites.

The findings demonstrate how a high-fat diet, rather than obesity itself, increases a molecule on T-helper cells called ST2 and this allows an increased T-helper 2 response which expels the parasite from the large intestinal lining.

Dr John Worthington from the Department of Biomedical and Life Science at Lancaster University co-led the research.

“We were quite surprised by what we found during this study. High-fat diets are mostly associated with increased pathology during disease. However, in the case of whipworm infection this high fat diet licenses the T-helper cells to make the correct immune response to expel the worm.”

Co-lead Professor Richard Grencis from the University of Manchester said: “Our studies in mice on a standard diet demonstrate that ST2 is not normally triggered when expelling the parasite, but the high-fat diet boosts the levels of ST2 and hence allows expulsion via an alternative pathway.”

Co-lead Professor David Thornton from the University of Manchester added: “It was really fascinating that simply altering the diet completely switched the immune response in the gut from one that fails to expel the parasite, to one that brings about all the correct mechanisms to eliminate it.”

However, Dr Worthington added caution to the findings.

“Before you order that extra take-away, we have previously published that weight loss can aid the expulsion of a different gut parasite worm. So these results may be context specific, but what is really exciting is the demonstration of how diet can profoundly alter the capacity to generate protective immunity and this may give us new clues for treatments for the millions who suffer from intestinal parasitic infections worldwide.”

Source: Lancaster University

Categories : AgeingTags :

Can Revitalising Old Blood Stem Cells Slow Ageing?

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Photo by Charlie-Helen Robinson on Pexels

Studies over the past several years have shown that infusions of young blood seem to produce a rejuvenating effect when infused into older bodies. Ageing hearts beat stronger, muscles become stronger, and thinking becomes sharper.

While some scientists have considered trying to replicate this effect with a pill, others have focused on rejuvenating the haematopoietic stem cells that actually make the blood – something which may be possible, based on recent findings from a study published in Nature Cell Biology.

“An ageing blood system, because it’s a vector for a lot of proteins, cytokines, and cells, has a lot of bad consequences for the organism,” says Emmanuelle Passegué, PhD, director of the Columbia Stem Cell Initiative, who’s been studying how blood changes with age. “A 70-year-old with a 40-year-old blood system could have a longer healthspan, if not a longer lifespan.”

Passegué, with her graduate student Carl Mitchell, found that an anti-inflammatory drug, already approved for use in rheumatoid arthritis, can turn back time in mice and reverse some of the effects of age on the hematopoietic system.

“These results indicate that such strategies hold promise for maintaining healthier blood production in the elderly,” Mitchell says.

Returning blood stem cells to a younger state

The researchers only identified the drug after a investigation of stem cells for blood and the niches where they reside in the centre of the bones.

All blood cells in the body are created by a small number of stem cells that reside in bone marrow. Over time, these haematopoietic stem cells start to change, producing fewer red blood cells (leading to anaemia) and fewer immune cells (which raises the risk of infection and impedes vaccination efforts), and they have trouble maintaining the integrity of their genomes (which can lead to blood cancers).

In a 2021 Journal of Experimental Medicine paper, Passegué and her team first tried to rejuvenate old haematopoietic stem cells in mice, with exercise or a calorie-restricted diet, both generally thought to slow the ageing process. Both failed, as did transplanting old stem cells into young bone marrow. Even young blood had no effect on rejuvenating old blood stem cells.

Mitchell and Passegué then took a closer look at the stem cells’ environment, the bone marrow. “Blood stem cells live in a niche; we thought what happens in this specialised local environment could be a big part of the problem,” Mitchell says.

With techniques developed in the Passegué lab that enable detailed investigation of the bone marrow milieu, the researchers found that the ageing niche is deteriorating and overwhelmed with inflammation, leading to dysfunction in the blood stem cells.

One inflammatory signal released from the damaged bone marrow niche, IL-1B, was critical in driving these ageing features, and blocking it with the drug, anakinra, remarkably returned the blood stem cells to a younger, healthier state.

Even more youthful effects on both the niche and the blood system occurred when IL-1B was prevented from exerting its inflammatory effects throughout the animal’s life.

The researchers are now trying to learn if the same processes are active in humans and if rejuvenating the stem cell niche earlier in life, in middle age, would be a more effective strategy.

Meanwhile, “treating elderly patients with anti-inflammatory drugs blocking IL-1B function should help with maintaining healthier blood production,” Passegué says, and she hopes the finding will lead to clinical testing.

“We know that bone tissue begins to degrade when people are in their 50s. What happens in middle age? Why does the niche fail first?” Passegué says. “Only by having a deep molecular understanding will it be possible to identify approaches that can truly delay ageing.”

Many societies have added more than 30 years to life expectancy in the past century. “Now it is imperative to conduct the science to determine how to create health and well-being across the full length of those lives,” says Linda Fried, MD, MPH, dean of the Mailman School of Public Health at Columbia University and director of the Butler Columbia Aging Center. “This must include research to understand the mechanisms of normal aging and how to fully develop the huge opportunities to create healthy longevity for all.”

Source: Columbia University Irving Medical Center

Categories : Ageing GenderTags :

Sex and Age Influence the Circadian Rhythm

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In a new study published in the journal Science, researchers exploring circadian molecular rhythms were able to uncover the organisation of gene expression rhythms in particular human tissues, and found that sex and age are involved, with females having a more regular pattern of rhythms.

In model organisms, analysing molecular rhythms is usually done using time-stamped measurements, but such data are not readily available in humans. To work around this, the researchers used existing measurements from a large cohort of post-mortem donors, combined with a novel computer algorithm that was designed to assign internal clock times to nearly one thousand donors.

“Interestingly, the data-science algorithm we developed turned out to resemble models from magnetic systems, which are well studied in statistical physics,” says study leader Felix Naef at Ecole Polytechnique Fédérale de Lausanne. Using this innovative approach, the researchers obtained the first comprehensive and accurate whole-organism view of 24-hour gene expression rhythms in 46 human tissues.

While the core clock machinery properties are conserved across the body and do not change significantly with sex and age, their analysis also revealed extensive programs of gene expression rhythms across major compartments of metabolism, stress response pathways and immune function, and these programs peaked twice a day.

In fact, the emerging whole-body organisation of circadian timing shows that rhythmic gene expression occurs as morning and evening waves, with the timing in the adrenal gland peaking first, while brain regions displayed much lower rhythmicity compared to metabolic tissues.

Dividing the donors by sex and age revealed a previously unknown richness of sex- and age- specific gene expression rhythms spread across biological functions. Strikingly, gene expression rhythms were sex-dimorphic (different in males and females) and more sustained in females, while rhythmic programs were generally reduced with age across the body.

Sex-dimorphic rhythms were particularly noticeable in the liver’s “xenobiotic detoxification,” the process by which liver breaks down harmful substances. Additionally, the study found that with age, the rhythm of gene expression decreases in the heart’s arteries, which may explain why older people are more susceptible to heart disease. This information could be useful in the field of “chronopharmacology,” which is the study of how a person’s internal clock affects the effectiveness and side effects of medication.

This study provides new insights into the complex interplay between our body clock, sex, and age. By understanding these rhythms, we might find new ways of diagnosing and treating pathologies such as sleep disorders and metabolic diseases.

Source: Ecole Polytechnique Fédérale de Lausanne

Categories : Environmental EffectsTags :

Traffic Noise may Increase the Risk of Tinnitus

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Photo by Dylan Hendricks on Unsplash

There is a correlation between traffic noise and risk of developing tinnitus, researchers have found. They point to a vicious cycle involving stress reactions and sleep disturbance as a potential cause. Living near a busy road, it may increase stress levels and affect sleep – and during times of stress and poor sleep, people may be at a higher risk of developing tinnitus.

Published in Environmental Health Perspectives, a new study with data from 3.5 million Danes has revealed that the more traffic noise Danish residents are exposed to in their homes, the more they are at risk of developing tinnitus.

Tinnitus is most clearly manifested by annoying whistling tones in the ears, which are disturbing for many.

Risk increases with noise levels

It is the first time that researchers have found a link between residential traffic noise exposure and hearing-related outcomes.

“In our data, we have found more than 40 000 cases of tinnitus and can see that for every ten decibels more noise in people’s home, the risk of developing tinnitus increases by six percent,” says Manuella Lech Cantuaria, PhD, Assistant Professor at the Mærsk Mc-Kinney-Møller Institute.

She and her colleague Jesper Hvass Schmidt, Associate Professor at the Department of Clinical Research and Chief Physician at Odense University Hospital (OUH) are concerned about the many health problems that traffic noise seems to cause. In 2021, they found a correlation between traffic noise and dementia.

“There is a need for more focus on the importance of traffic noise for health. It is alarming that noise seems to increase the risk of tinnitus, cardiovascular diseases and dementia, among other diseases,” says Jesper Hvass Schmidt.

Tip of the iceberg

Only the worst cases of tinnitus are referred from their own doctor or an otorhinolaryngologist. The high number of reported cases of tinnitus are probably only the tip of the iceberg, he believes.

“In general, about ten percent of the population experience tinnitus from time to time. It is associated with stress and poor sleep, which can be worsened by traffic noise, and here we have a potential cycle.”

More studies are needed so that researchers can be sure that traffic noise causes tinnitus, and how this happens.

“But we know that traffic noise can make us stressed and affect our sleep. And that tinnitus can get worse when we live under stressful situations and we do not sleep well,” Jesper Hvass Schmidt says.

Nighttime noise is worse

The researchers believe that noise at nighttime can be even worse for health. It affects our sleep, which is so important for restoring both our physical and mental health. “Therefore, it is worth considering whether you can do something to improve your sleep if you live next to a busy road,” Manuella Lech Cantuaria says.

What to do

In the study, higher associations were found when noise was measured at the quiet side of their houses, that is, the side facing away from the road. This is where most people would place their bedroom whenever possible, therefore researchers believe this is a better indicator of noise during sleep.

“There are different things one can do to reduce noise in their homes, for example by sleeping in a room that does not face the road or by installing soundproof windows,” says Manuella Lech Cantuaria.

But not everyone has those options, so she says that traffic noise should be considered a health risk to be taken into account in urban planning and political decision-making.

Electric cars will not make cities quieter

The Danish guidance level for harmful traffic noise is 58 decibels. It is a myth that replacing fuel cars by electric cars can significantly reduce traffic noise exposure at people’s houses. The noise comes mainly from the contact between the tires and the road.

Source: University of Southern Denmark Faculty of Health Sciences