Comment

Comment by Dr. Krishna Kumari Challa on October 13, 2023 at 10:51am

By the numbers

• 97: Percentage of patients who develop anemia after eight days in the ICU
• 50: Percentage of transfusions given in the ICU in the absence of active bleeding
• 41: Amount of blood (in ml) taken per ICU patient per day for routine blood tests (equivalent of one full blood donation every eight days)
• 75: Percentage of patients who receive at least one blood transfusion within seven days of ICU admission (40% of all ICU patients)
• $450: Cost per unit of blood in Canada (not including indirect costs associated with testing, preparation, storage, administration, reactions)
• 90: Percentage of blood that is wasted in routine lab tests
• 10: Units of blood that could be saved per 100 patients with ICU stays of more than 48 hours if the results of this study were implemented

 Small-Volume Blood Collection Tubes to Reduce Transfusions in Intensive Care, JAMA (2023). DOI: 10.1001/jama.2023.20820. jamanetwork.com/journals/jama/ … 1001/jama.2023.20820

Part 2

Comment by Dr. Krishna Kumari Challa on October 13, 2023 at 10:50am

Large trial shows taking less blood for lab testing reduces transfusions in intensive care

A world-first clinical trial published in JAMA could provide an easy way to save tens of thousands of units of blood every year worldwide.

The trial, which involved more than 27,000 patients in 25 adult intensive care units (ICUs) across Canada, showed that taking less blood for lab tests using "small-volume" tubes reduced the need for almost one blood transfusion for every 10 patients. Most hospitals use standard tubes that automatically draw four to six milliliters (ml) of blood, but a typical laboratory test requires less than 0.5 ml of blood, meaning the rest (more than 90%) is wasted. Commercially available small-volume tubes have a weaker vacuum inside that automatically draws up to half as much blood. "While the amount of blood drawn per tube is relatively small, ICU patients typically require multiple blood samples taken multiple times every day. This can add up to significant blood loss that contributes to anemia, or low red blood cells. ICU patients are unable to produce more red blood cells to correct for this blood loss and often require treatment with a blood transfusion.

This trial showed that we can save one blood transfusion for every 10 ICU patients by simply switching to small-volume tubes for blood collection.

At a time when everyone is trying to find ways to make health care more sustainable, and preserve our supply of blood products, this study provides a simple solution that can be implemented without additional cost or negative effects. The study also has important implications for patients, as low red blood cells (anemia) can leave patients feeling tired and weak and is associated with can lead to other complications and longer hospital stays. While blood transfusions can usually correct anemia, there can be rare side effects, such as difficulty breathing, allergic reactions and infections.
Part 1

Comment by Dr. Krishna Kumari Challa on October 13, 2023 at 10:38am

Restoring nerve-muscle connections boosts strength of aging mice, study finds

A small molecule previously shown to enhance strength in injured or old laboratory mice does so by restoring lost connections between nerves and muscle fibers,  researchers have found.

The molecule, called PGE2, blocks the activity of an aging-associated enzyme, or gerozyme, called 15-PGDH that naturally increases in muscles as they age. The study showed that levels of the gerozyme increase in muscles after nerve damage and that it is prevalent in muscle fibers of people with neuromuscular diseases. The research is the first to show that damaged motor neurons—nerves connecting the spinal cord to muscles—can be induced to regenerate in response to a drug treatment and that lost strength and muscle mass can be at least partially regained. It suggests that, if similar results are seen in humans, the drug may one day be used to prevent muscle loss of muscle strength due to aging or disease or to hasten recovery from injury.

 Mohsen A. Bakooshli et al, Regeneration of neuromuscular synapses after acute and chronic denervation by inhibiting the gerozyme 15-prostaglandin dehydrogenase, Science Translational Medicine (2023). DOI: 10.1126/scitranslmed.adg1485

Comment by Dr. Krishna Kumari Challa on October 13, 2023 at 10:22am

To explore this avenue, the researchers recruited 22 people without sleep disorders and 27 patients with narcolepsy—that is, people who experience uncontrollable episodes of daytime sleepiness. People with narcolepsy have the particularity of having many lucid dreams,  in which they are aware of being asleep; some can sometimes even shape their dream scenario as they wish.

In addition, they easily and quickly enter REM sleep (the stage where lucid dreaming occurs) during the day, making them good candidates for studying consciousness during sleep under experimental conditions.

Participants in the study were asked to take a nap. The researchers gave them a "lexical decision" test, in which a human voice pronounced a series of real and made-up words. Participants had to react by smiling or frowning to categorize them into one or the other of these categories. Throughout the experiment, they were monitored by polysomnography—a comprehensive recording of their brain and heart activity, eye movements, and muscle tone.

Upon waking up, participants had to report whether they had or had not had a lucid dream during their nap and whether they remembered interacting with someone.

Most of the participants, whether narcoleptic or not, responded correctly to verbal stimuli while remaining asleep. These events were certainly more frequent during lucid dreaming episodes, characterized by a high level of awareness. 

By cross-referencing these physiological and behavioral data and the participants' subjective reports, the researchers also showed that it is possible to predict the opening of these windows of connection with the environment, i.e., the moments when sleepers were able to respond to stimuli. They were announced by an acceleration in brain activity and by physiological indicators usually associated with rich cognitive activity.

Türker B. et al. Behavioral and brain responses to verbal stimuli reveal transient periods of cognitive integration of the external world during sleep. Nature Neuroscience (2023). DOI: 10.1038/s41593-023-01449-7. www.nature.com/articles/s41593-023-01449-7

Part 3

Comment by Dr. Krishna Kumari Challa on October 13, 2023 at 10:20am

Even if it seems familiar because we indulge in it every night, sleep is a highly complex phenomenon. Our research has taught us that wakefulness and sleep are not stable states: on the contrary, we can describe them as a mosaic of conscious and seemingly unconscious moments. It is essential to decipher the brain mechanisms underlying these intermediate states between wakefulness and sleep. "When they are dysregulated, they can be associated with disorders such as sleepwalking, sleep paralysis, hallucinations, the feeling of not sleeping all night, or on the contrary of being asleep with your eyes open.

To distinguish between wakefulness and the different stages of sleep, researchers usually use physiological indicators such as specific brain waves made visible through electroencephalography. Unfortunately, these indicators do not provide a detailed picture of what is happening in the minds of sleepers; sometimes, they even contradict their testimonies.

Part 2

Comment by Dr. Krishna Kumari Challa on October 13, 2023 at 10:18am

Study finds we can respond to verbal stimuli while sleeping

Sleep is not a state in which we are completely isolated from our environment: while we sleep, we are capable of hearing and understanding words. These observations, the result of close collaboration between various research teams call into question the very definition of sleep and the clinical criteria that make it possible to distinguish between its different stages.

Sleep is generally defined as a period during which the body and mind are at rest—as if disconnected from the world. However, a new study shows that the frontier between wakefulness and sleep  is much more porous than it seems.

The researchers have shown that ordinary sleepers can pick up verbal information transmitted by a human voice and respond to it by contracting their facial muscles. This astonishing ability occurs intermittently during almost all stages of sleep—like windows of connection with the outside world were temporarily opened on this occasion. These new findings suggest that it may be possible to develop standardized communication protocols with sleeping individuals to understand better how mental activity changes during sleep. On the horizon: a new tool to access the cognitive processes that underlie both normal and pathological sleep.

Part 1

Comment by Dr. Krishna Kumari Challa on October 13, 2023 at 10:10am

Simulations of 'backwards time travel' can improve scientific experiments

Physicists have shown that simulating models of hypothetical time travel can solve experimental problems that appear impossible to solve using standard physics.

If gamblers, investors and quantum experimentalists could bend the arrow of time, their advantage would be significantly higher, leading to significantly better outcomes. Researchers at the University of Cambridge have shown that by manipulating entanglement—a feature of quantum theory that causes particles to be intrinsically linked—they can simulate what could happen if one could travel backwards in time. So that gamblers, investors and quantum experimentalists could, in some cases, retroactively change their past actions and improve their outcomes in the present. Whether particles can travel backwards in time is a controversial topic among physicists, even though scientists have previously simulated models of how such spacetime loops could behave if they did exist. By connecting their new theory to quantum metrology, which uses quantum theory to make highly sensitive measurements, the Cambridge team has shown that entanglement can solve problems that otherwise seem impossible.

 David R. M. Arvidsson-Shukur et al, Nonclassical Advantage in Metrology Established via Quantum Simulations of Hypothetical Closed Timelike Curves, Physical Review Letters (2023). DOI: 10.1103/PhysRevLett.131.150202

Comment by Dr. Krishna Kumari Challa on October 12, 2023 at 10:35am

Gene editing makes chickens flu-resistant

The same lab that cloned Dolly the sheep has used gene editing to create chickens resistant to avian flu

The proof of concept still needs to be refined to achieve full protection and address the challenges of practical application

Bird-flu-resistant chickens have been created using CRISPR gene editing. When exposed to the flu virus, nine out of ten of the animals remained uninfected and didn’t pass the virus to other birds. Researchers modified a gene encoding a chicken protein that the virus needs to replicate. But this prompted the virus to start replicating using other proteins in the same family, which the researchers think could be addressed with more edits. “We must be careful not to facilitate adaptations of the virus that make it more dangerous than it [already] is,” says virologist and study co-author Wendy Barclay.

https://english.elpais.com/science-tech/2023-10-10/the-same-lab-tha...

https://www.nature.com/articles/s41467-023-41476-3.epdf?sharing_tok...

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Comment by Dr. Krishna Kumari Challa on October 12, 2023 at 9:55am

Why this type of dispersal not seen among other insects? 

The eggs of most insect species are typically fertilized just before being laid, relying on sperm stored within the female insects after copulation. However, in some stick insect species, females are parthenogenic, that is, they can produce viable eggs without fertilization. It is only because of this quirk in their nature that viable stick insect babies can hatch from the eggs.

Suetsugu Kenji et al, Phylogeographical evidence for historical long-distance dispersal in the flightless stick insect Ramulus mikado, Proceedings of the Royal Society B: Biological Sciences (2023). DOI: 10.1098/rspb.2023.1708. royalsocietypublishing.org/doi … .1098/rspb.2023.1708

Part 2

Comment by Dr. Krishna Kumari Challa on October 12, 2023 at 9:54am

Birds disperse eaten insects' eggs

Relationship patterns among flightless stick insects suggest that birds disperse the eggs after eating gravid females. Now this is shown to be true in a new study.

 Most species of stick insects are flightless, yet they are distributed over wide distances and across geographical features that would impede the expansion of flightless animals. This has caused researchers to think that their eggs might be dispersed by birds feeding on gravid females, much in the same way as many plant species rely on birds eating their seeds together with fruits and dispersing them while the seeds pass through the digestive tracts of the birds unharmed.

Experimental studies with Ramulus mikado, a common stick insect in Japan, had suggested that this is possible, but since direct observation of such an event in nature is highly unlikely, it has been unclear whether this mechanism actually contributes to the distribution of the insect.

So researchers turned to the analysis of the relationship patterns of Ramulus mikado populations. They made use of the idea of genetic isolation by geographic distance. 

According to this idea, when individual dispersal distances are smaller, such as in flightless insects, the accumulation of genetic mutations eventually leads to a positive correlation between genetic differentiation among locations and the geographic distance that separates them. Thus, the genetic variation between different populations can be a proxy for the species' rate of dispersal.

The results, published in the journal Proceedings of the Royal Society B, paint a vivid picture. Among many genes where the differences correlated with the geographic distance, the team found a few examples of genes that were clearly closely related even though they were geographically separated by up to hundreds of kilometers and across geographic features that these animals usually cannot overcome.

Astonishingly, amidst a sea of limited active dispersal, they discovered identical genotypes jumping across vast distances, strongly indicating the past occurrence of passive long distance genetic dispersal.

In other words, a few of the flightless insects must have flown from place to place, and the only plausible way in which this could happen is that the eggs of the insects survive the passage through the digestive tract of birds that eat them.

And the insect eggs were seen in bird faeces. 

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