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Comment by Dr. Krishna Kumari Challa on January 31, 2022 at 6:42am

Pulse oximeter measurements of blood oxygen levels are unreliable in assessing severity of Covid-19 pneumonia

The severity of Covid-19 pneumonia can be difficult to assess in people from different ethnic groups, due to inaccurate readings from a device that measures the level of oxygen in the blood of patients.

The findings of the research, published in the European Respiratory Journal, show that pulse oximeters gave false readings of nearly 7% higher in a group of patients of Mixed ethnicity with Covid-19, compared to White patients at just over 3%. There were also falsely high readings in patients with both Black and Asian ethnicity, which could delay patients receiving the best and most timely treatment for the virus.

Pulse oximetry is a non-invasive test that measures the oxygen saturation level of the blood. It can rapidly detect even small changes in oxygen levels. These levels show how efficiently blood is carrying oxygen to the extremities furthest from the heart, including the arms and legs. Medical professionals routinely use them in primary care and critical care settings like emergency rooms or hospitals to monitor the clinical status of their patients.

The light wave transmission that this technology uses is modified by skin pigmentation and may vary by skin colour. A recent study reported different outputs in patients with Black skin compared to patients with White skin, which has the potential to adversely affect patient care. This led to the Food and Drink Administration in the USA releasing an expression of concern about the accuracy of pulse oximeters in 2021, which led to the current study.

Researchers  made use of the electronic datasets that are collected for clinical use in real time, but archived and available to answer important clinical questions and improve both patient care and patient safety in the future. The NUH Covid-19 Patient Safety Database is anonymised to allow lessons to be learned without compromising individual patient confidentiality. The team included clinicians, managers, statisticians, computer analysts, software coders and data warehouse archivists.

The team of experts from Nottingham used data from patients with Covid-19 infection to look at the difference in blood oxygen levels as measured by pulse oximetry and arterial blood gas tests, spilt into different ethnic groups over a wide range of oxygen saturations. Arterial blood gas tests measure the levels of oxygen in the blood from an artery, and represent the gold standard measurement for oxygen levels.

Part1

Comment by Dr. Krishna Kumari Challa on January 28, 2022 at 12:47pm

How do algae survive excess oxygen?

Comment by Dr. Krishna Kumari Challa on January 28, 2022 at 12:30pm

What wintering squirrels can teach astronauts

When bears and ground squirrels hibernate in winter, they stop eating, lasting until spring simply on the fat reserves they've stored up in their bodies. Usually, this sort of prolonged fasting and inactivity would significantly reduce the mass and function of muscle, but hibernators don't suffer this fate. How they avoid it, however, has been a mystery.

Now, in research published in Science,  biologists have figured out why, and their findings could have implications for, of all things, the future of space travel . By studying a variety called the 13-lined ground squirrel that is common in North America, researchers have confirmed a theory known as "urea nitrogen salvage" dating back to the 1980s.

The theory posits that hibernators harness a metabolic trick of their gut microbes to recycle the nitrogen present in urea, a waste compound that is usually excreted as urine, and use it to build new tissue proteins.

How could this discovery be of use in space? Theoretically by helping astronauts minimize their own muscle-loss problems caused by microgravity-induced suppression of protein synthesis and which they now try to reduce by intensively exercising.

If a way could be found to augment the astronauts' muscle protein synthesis processes using urea nitrogen salvage, they could be able to achieve better muscle health during long voyages into deep space in spacecraft too small for the usual exercise equipment, the argument goes.

Matthew D. Regan et al, Urea nitrogen recycling via gut symbionts increases in hibernating ground squirrels over the winter, Science (2022). DOI: 10.1126/science.abh2950. www.science.org/doi/10.1126/science.abh2950

https://phys.org/news/2022-01-wintering-squirrels-astronauts.html?u...

Comment by Dr. Krishna Kumari Challa on January 27, 2022 at 9:35am

Bacteria build communities using chemical signals comparable to radio waves

UCLA-led study could have implications for medical and sustainability research

The thought of bacteria joining together to form a socially organized community capable of cooperation, competition and sophisticated communication might at first seem like the stuff of science fiction — or just plain gross.

But biofilm communities have important implications for human health, from causing illness to aiding digestion. And they play a role in a range of emerging technologies meant to protect the environment and generate clean energy.

New UCLA-led research could give scientists insights that will help them cultivate useful microbes or clear dangerous ones from surfaces where biofilms have formed — including on tissues and organs in the human body. The study, published in the Proceedings of the National Academies of Science, describes how, when biofilms form, bacteria communicate with their descendants using a chemical signal analogous to radio transmissions.

The investigators showed that concentration levels of a messenger molecule called cyclic diguanylate, or c-di-GMP, can increase and decrease in well-defined patterns over time, and across generations of bacteria. Bacteria cells employ those chemical signal waves, the study found, to encode information for their descendants that helps coordinate colony formation.

In that phenomenon, whether a given cell attaches to a surface is influenced by the specific shape of those oscillations — much like the way information is stored in AM and FM radio waves.

https://www.pnas.org/content/119/4/e2112226119

Comment by Dr. Krishna Kumari Challa on January 27, 2022 at 9:24am

New hair dyes avoid allergic reactions

A bad dye job is bad enough on its own, but an itchy and irritating allergic reaction to it is even worse. And people who become allergic to hair dye can develop reactions to many other common substances, transforming a simple cosmetic treatment into a big problem. Now, researchers reporting in ACS Sustainable Chemistry & Engineering have developed a range of permanent hair dyes that avoid the allergenic properties of traditional formulations.

When applied as hair color, paraphenylenediamine (PPD)—a common ingredient in permanent dyes—undergoes a chemical reaction that turns the hair a dark color that won't wash out over time. This reaction, however, can also produce compounds that bind proteins in the user's skin, causing allergic responses, such as eczema and facial swelling. PPD can also sensitize users to other substances, including a compound commonly found in sunscreens and cosmetics, as well as common pigment and ink compounds. Alternatives have been proposed, but they generally are not water-soluble, and the safety of some of the compounds are not well understood. Researchers wanted to create new alternatives that would avoid the problems of PPD while still providing permanent hair coloring.

The team prepared seven dyes based on PPD with modifications to the aromatic amine core. The modifications were chosen to potentially make the compounds less reactive toward proteins and less able to be absorbed into skin. All seven compounds permanently colored hair samples, producing a range of hues from rosy pinks to deep blacks that did not fade, even after three weeks of daily washing. The team then examined the dyes in a test commonly used in the cosmetics industry to determine if a product is a skin sensitizer. Five of the modified dyes were "weak" sensitizers, whereas PPD was "moderate." Another test showed that the new compounds generated a reduced inflammatory response in cells compared to PPD. These results suggest that the new dyes can effectively color hair while also avoiding the potential allergenic and sensitization risks of more traditional ones.

opalakrishnan Venkatesan et al, Synthesis and Assessment of Non-allergenic Aromatic Amine Hair Dyes as Efficient Alternatives to Paraphenylenediamine, ACS Sustainable Chemistry & Engineering (2022). DOI: 10.1021/acssuschemeng.1c06313

https://phys.org/news/2022-01-hair-dyes-allergic-reactions.html?utm...

Comment by Dr. Krishna Kumari Challa on January 27, 2022 at 9:19am

Are There Oceans on Other Worlds?

Comment by Dr. Krishna Kumari Challa on January 27, 2022 at 8:57am

Animals naturally capable of regeneration live mostly in an aquatic environment. The first stage of growth after loss of a limb is the formation of a mass of stem cells at the end of the stump called a blastema, which is used to gradually reconstruct the lost body part. The wound is rapidly covered by skin cells within the first 24 hours after the injury, protecting the reconstructing tissue underneath.

"Mammals and other regenerating animals will usually have their injuries exposed to air or making contact with the ground, and they can take days to weeks to close up with scar tissue.

Using the BioDome cap in the first 24 hours helps mimic an amniotic-like environment which, along with the right drugs, allows the rebuilding process to proceed without the interference of scar tissue."

Nirosha J. Murugan et al, Acute multidrug delivery via a wearable bioreactor facilitates long-term limb regeneration and functional recovery in adult Xenopus laevis, Science Advances (2022). DOI: 10.1126/sciadv.abj2164. www.science.org/doi/10.1126/sciadv.abj2164

https://medicalxpress.com/news/2022-01-regrow-frog-lost-leg.html?ut...

Comment by Dr. Krishna Kumari Challa on January 27, 2022 at 8:56am

Researchers regrow frog's lost leg

For millions of patients who have lost limbs for reasons ranging from diabetes to trauma, the possibility of regaining function through natural regeneration remains out of reach. Regrowth of legs and arms remains the province of salamanders and superheroes.

But in a study published in the journal Science Advances, scientists at Tufts University and Harvard University's Wyss Institute have brought us a step closer to the goal of regenerative medicine.

On adult frogs, which are naturally unable to regenerate limbs, the researchers were able to trigger regrowth of a lost leg using a five-drug cocktail applied in a silicone wearable bioreactor dome that seals in the elixir over the stump for just 24 hours. That brief treatment sets in motion an 18-month period of regrowth that restores a functional leg.

Many creatures have the capability of full regeneration of at least some limbs, including salamanders, starfish, crabs, and lizards. Flatworms can even be cut up into pieces, with each piece reconstructing an entire organism. Humans are capable of closing wounds with new tissue growth, and our livers have a remarkable, almost flatworm-like capability of regenerating to full size after a 50% loss.

But loss of a large and structurally complex limb—an arm or leg—cannot be restored by any natural process of regeneration in humans or mammals. In fact, we tend to cover major injuries with an amorphous mass of scar tissue, protecting it from further blood loss and infection and preventing further growth.

researchers triggered the regenerative process in African clawed frogs by enclosing the wound in a silicone cap, which they call a BioDome, containing a silk protein gel loaded with the five-drug cocktail.

Each drug fulfilled a different purpose, including tamping down inflammation, inhibiting the production of collagen which would lead to scarring, and encouraging the new growth of nerve fibers, blood vessels, and muscle. The combination and the bioreactor provided a local environment and signals that tipped the scales away from the natural tendency to close off the stump, and toward the regenerative process.

The researchers observed dramatic growth of tissue in many of the treated frogs, re-creating an almost fully functional leg. The new limbs had bone structure extended with features similar to a natural limb's bone structure, a richer complement of internal tissues (including neurons), and several "toes" grew from the end of the limb, although without the support of underlying bone.

The regrown limb moved and responded to stimuli such as a touch from a stiff fiber, and the frogs were able to make use of it for swimming through water, moving much like a normal frog would.

Part 1

Comment by Dr. Krishna Kumari Challa on January 26, 2022 at 1:35pm

Researchers recruited a total of 104 people, all OHSU employees who were vaccinated by the Pfizer vaccine, and then carefully divided them into three groups: 42 who were vaccinated with no infection, 31 who were vaccinated after an infection, and 31 who had breakthrough infections following vaccination. Controlling for age, sex and time from vaccination and infection, the researchers drew blood samples from each participant and exposed the samples to three variants of the live SARS-CoV-2 virus in a Biosafety Level 3 lab . 

They found both of the groups with "hybrid immunity" generated greater levels of immunity compared with the group that was vaccinated with no infection.

1. Timothy A. Bates, Savannah K. McBride, Hans C. Leier, Gaelen Guzman, Zoe L. Lyski, Devin Schoen, Bradie Winders, Joon-Yong Lee, David Xthona Lee, William B. Messer, Marcel E. Curlin, Fikadu G. Tafesse. Vaccination before or after SARS-CoV-2 infection leads to robust humoral response and antibodies that effectively neutralize variants. Science Immunology, 2022; DOI: 10.1126/sciimmunol.abn8014
2. Timothy A. Bates, Savannah K. McBride, Bradie Winders, Devin Schoen, Lydie Trautmann, Marcel E. Curlin, Fikadu G. Tafesse. Antibody Response and Variant Cross-Neutralization After SARS-CoV-2 Breakthrough Infection. JAMA, 2022; 327 (2): 179 DOI: 10.1001/jama.2021.22898

https://researchnews.cc/news/11272/New-study-suggests-two-paths-tow...

Part 2

Comment by Dr. Krishna Kumari Challa on January 26, 2022 at 1:33pm

New study suggests two paths toward 'super immunity' to COVID-19

New laboratory research from Oregon Health & Science University reveals more than one path toward robust immunity from COVID-19.

A new study finds that two forms of immunity—breakthrough infections following vaccination or natural infection followed by vaccination—provide roughly equal levels of enhanced immune protection.

The new study was published in the journal Science Immunology.

It makes no difference whether you get infected-and-then-vaccinated, or if you get vaccinated-and-then-a-breakthrough infection. In either case, you will get a really, really robust immune response—amazingly high.

The research follows an OHSU study published in December that described extremely high levels of immune response following breakthrough infections—so-called "super immunity." That study was the first to use multiple live SARS-CoV-2 variants to measure cross-neutralization of blood serum from breakthrough cases.

The new study found that it doesn't matter whether someone gets a breakthrough infection or gets vaccinated after a natural infection. In both cases, the immune response measured in blood serum revealed antibodies that were equally more abundant and more potent—at least 10 times more potent—than immunity generated by vaccination alone.

The study was done before the emergence of the omicron variant, but researchers expect the hybrid immune responses would be similar with the new highly transmissible variant.

The likelihood of getting breakthrough infections is high because there is so much virus around us right now. But we position ourselves better by getting vaccinated. And if the virus comes, we'll get a milder case and end up with this super immunity.

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