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Comment by Dr. Krishna Kumari Challa on October 24, 2024 at 11:57am

The Human Mind Isn't Meant to Be Awake After Midnight, Scientists Warn

In the middle of the night, the world can sometimes feel like a dark place. Under the cover of darkness, negative thoughts have a way of drifting through your mind, and as you lie awake, staring at the ceiling, you might start craving guilty pleasures

Plenty of evidence suggests the human mind functions differently if it is awake at nighttime. Past midnight, negative emotions tend to draw our attention more than positive ones, dangerous ideas grow in appeal and inhibitions fall away. Some researchers think the human circadian rhythm is heavily involved in these critical changes in function, as they outline in a 2022 paper(1) summarizing the evidence of how brain systems function differently after dark.

Their hypothesis, called 'Mind After Midnight', suggests the human body and the human mind follow a natural 24-hour cycle of activity that influences our emotions and behavior.

In short, at certain hours, our species is inclined to feel and act in certain ways. In the daytime, for instance, molecular levels and brain activity are tuned to wakefulness. But at night, our usual behavior is to sleep.

From an evolutionary standpoint this, of course, makes sense. Humans are much more effective at hunting and gathering in the daylight, and while nighttime is great for rest, humans were once at greater risk of becoming the hunted.

According to the researchers, to cope with this increased risk our attention to negative stimuli is unusually heightened at night. Where it might once have helped us jump at invisible threats, this hyper-focus on the negative can then feed into an altered reward/motivation system, making a person particularly prone to risky behaviours.

Add sleep loss to the equation, and this state of consciousness only becomes more problematic.

The authors of the hypothesis use two examples to illustrate their point. The first example is of a heroin user who successfully manages their cravings in the day but succumbs to their desires at night.

Part 1

Comment by Dr. Krishna Kumari Challa on October 24, 2024 at 11:48am

The team also experimented with different delays, connecting brains to the liver-assisted system at intervals of 30 minutes, 50 minutes, 60 minutes, and 240 minutes. The longest interval that showed the most promise was 50 minutes after being deprived of blood: the brain restarted electrical activity, and was maintained in that state for six hours until the experiment was shut off.
Remarkably, in brains that had been starved of oxygen for 60 minutes, activity only returned for three hours before fading, suggesting a critical interval in which resuscitation can be successful with the addition of a functioning liver.

These results, the researchers say, suggest the liver plays an important role in the development of brain injury following cardiac arrest. The findings suggest new avenues for research into brain injury, and may, hopefully, improve survival rates and recovery outcomes for human patients in the future.

https://www.embopress.org/doi/full/10.1038/s44321-024-00140-z

Part 3

Comment by Dr. Krishna Kumari Challa on October 24, 2024 at 11:46am

When the pigs were euthanized and their brains examined, the control group obviously had the least brain damage; but the group that had not been subjected to liver ischemia showed significantly less brain damage than the group that had.

The next stage of the research involved attempting to incorporate an undamaged liver into the life support system reviving a brain that had been removed from a euthanized pig entirely. This is unlikely to be a scenario used to treat humans, but it helps scientists understand the windows in which resuscitation may be viable.

The basic life support system involved an artificial heart and lungs to help pump fluid through the brain. For one group, a pig's liver was integrated into the system, known as liver-assisted brain normothermic machine perfusion.

First, brains were connected to the life support systems 10 minutes after commencement of the life support procedure. For the system without a liver, electrical activity in the brain emerged within half an hour before declining over time.
Part 2

Comment by Dr. Krishna Kumari Challa on October 24, 2024 at 11:45am

Scientists Revived a Pig's Brain Nearly a Whole Hour After It Died

Scientists have revived activity in the brains of pigs up to nearly an hour after circulation had ceased. In some cases, functionality was sustained for hours through a surprising discovery by researchers.

 This achievement represents a huge step forward in working out how to restore brain function after a patient has suffered a sudden cardiac arrest. It suggests that doctors may be able to widen the brief window for successful resuscitation of patients following cardiac arrest.

The trick? Incorporating the patient's unharmed liver – the organ the body uses to purify its blood – into the life support system used to revive the brain after the time had elapsed.

Sudden cardiac arrest causes a lot of problems in the body due to the rapid cessation of blood flow. The subsequent drop in circulation to parts of the body is called ischemia, and when it occurs in the brain, it can cause serious, irreparable damage within minutes. This is why the resuscitation window for cardiac arrest is so short.

It's known that multi-organ ischemia plays a role in the brain's ability to recover after a cardiac arrest, but the individual organs have not been fully investigated.

In recent years, scientists have been using pig models to test methods for limiting brain injury. Supervised by physician Xiaoshun He of Sun Yat-Sen University in China, a team of scientists has turned to the animal to try and understand the role of the liver in brain recovery after ischemia due to cardiac arrest.

Using 17 lab-raised Tibetan minipigs, the team compared the inclusion of a liver in a loss of circulation. In one set of experiments, two groups of pigs were subjected to brain ischemia for 30 minutes; one of the groups was also subjected to liver ischemia, and the other was not. Meanwhile a control group underwent no ischemia.

Part 1

Comment by Dr. Krishna Kumari Challa on October 24, 2024 at 11:07am

Experiments find people assume unidentified bystanders in a war zone are combatants, acceptable collateral damage

People's bias toward sacrificing unknown bystanders appears to stem from assuming the unidentified person is an enemy, according to a study published October 23, 2024, in the open-access journal PLOS ONE.

About as many civilians as soldiers die in war each year, some during strikes targeted at enemy combatants. There have been many reported cases of mistaking innocent civilians for enemy combatants, with the possibility of many more being unreported.

Researchers conducted five experiments to test when people assume unknown bystanders in a combat zone are enemies rather than civilians, reducing their concerns about collateral damage. A total of 2,204 participants were presented with a realistic moral dilemma: A military pilot must decide whether to bomb a dangerous enemy target, also killing a bystander. 

In the study, few people endorsed bombing when the bystander was known to be an innocent civilian. However, when the bystander's identity was unknown, more than twice as many people endorsed the bombing despite no evidence they were enemies.

Bombing endorsement was predicted by attitudes toward total war: the theory that there should be no distinction between military and civilian targets in wartime conflict. 

According to the authors, these findings have implications for military strategists who must decide whether to attack areas with enemy militants and unidentified bystanders. The results support a common tendency in people to assume the bystanders are enemies, with important consequences if they turn out to be innocent civilians.

The real-world cases of civilians struck by bombs could result from the same error in judgment reported in this study.

What I don't know can hurt you: Collateral combat damage seems more acceptable when bystander victims are unidentified, PLoS ONE (2024). DOI: 10.1371/journal.pone.0298842

Comment by Dr. Krishna Kumari Challa on October 24, 2024 at 10:52am

'Inflexible thinking style' behind why some people won't accept vaccines, says new research

An "inflexible thinking style" could explain why some people are hesitant about taking a vaccine, new research  has revealed. It is a finding that could have implications for public health policy, especially during pandemics.

Researchers  conducted the first study evaluating the relationship between COVID-19 "vaccine hesitancy and cognitive flexibility."

Cognitive flexibility is how good people are at responding to changing situations and changing feedback, and especially when rules change. Inflexibility is generally described as the incapacity to adjust one's behavior in response to changing circumstances, update one's knowledge, and maintain optimum decision-making.

This explorative study found that those with greater vaccine hesitancy persisted with the same erroneous responses during a computerized test of flexible thinking, even when they received direct feedback telling them that their responses were no longer correct. This response pattern is the hallmark of a cognitively inflexible thinking style.

Vaccine hesitancy is quite common, occurring in approximately 12% of the population and may occur for multiple underlying reasons. In this study, researchers found the relationship between it and cognitive inflexibility can be predicted through an online test. This may be of value for public health policy in identifying this specific group.

The research, conducted between June 2021 and July 2022 after lockdown from COVID-19 was eased, has just been published in the Journal of Psychiatric Research.

L. Pellegrini et al, The inflexible mind: A critical factor in understanding and addressing COVID-19 vaccine hesitancy, Journal of Psychiatric Research (2024). DOI: 10.1016/j.jpsychires.2024.09.028

Comment by Dr. Krishna Kumari Challa on October 24, 2024 at 10:33am

Scientists glue two proteins together, driving cancer cells to self-destruct

Our bodies divest themselves of 60 billion cells every day through a natural process of cell culling and turnover called apoptosis. These cells—mainly blood and gut cells—are all replaced with new ones, but the way our bodies rid themselves of material could have profound implications for cancer therapies in a new approach developed by  researchers.

They aim to use this natural method of cell death to trick cancer cells into disposing of themselves. Their method accomplishes this by artificially bringing together two proteins in such a way that the new compound switches on a set of cell death genes, ultimately driving tumor cells to turn on themselves.

The researchers describe their latest such compound in a paper published Oct. 4 in Science.

Apoptosis turns out to be critical for many biological processes, including proper development of all organs and the fine-tuning of our immune systems. That system retains pathogen-recognizing cells but kills off self-recognizing ones, thus preventing autoimmune disease.

Traditional treatments for cancer—namely chemotherapy and radiation—often kill large numbers of healthy cells alongside the cancerous ones. To harness cells' natural and highly specific self-destruction abilities, researchers developed a kind of molecular glue that sticks together two proteins that normally would have nothing to do with one another.

One of these proteins, BCL6, when mutated, drives the blood cancer known as diffuse large cell B-cell lymphoma. This kind of cancer-driving protein is also referred to as an oncogene. In lymphoma, the mutated BCL6 sits on DNA near apoptosis-promoting genes and keeps them switched off, helping the cancer cells retain their signature immortality.

The researchers developed a molecule that tethers BCL6 to a protein known as CDK9, which acts as an enzyme that catalyzes gene activation, in this case, switching on the set of apoptosis genes that BCL6 normally keeps off.

When the team tested the molecule in diffuse large cell B-cell lymphoma cells in the lab, they found that it indeed killed the cancer cells with high potency. They also tested the molecule in healthy mice and found no obvious toxic side effects, even though the molecule killed off a specific category of the animals' healthy B cells, a kind of immune cell, which also depends on BCL6.

They're now testing the compound in mice with diffuse large B-cell lymphoma to gauge its ability to kill cancer in a living animal.

The research team hopes that by blasting the cells with multiple different cell death signals at once, the cancer will not be able to survive long enough to evolve resistance, although this idea remains to be tested.

Roman C. Sarott et al, Relocalizing transcriptional kinases to activate apoptosis, Science (2024). DOI: 10.1126/science.adl5361

Comment by Dr. Krishna Kumari Challa on October 24, 2024 at 9:51am

To test the obstetrical dilemma hypothesis, the research team first compared the available space in the birth canal of chimpanzees and humans, using the average distance between the fetal head and the pelvic bones while accounting for soft tissue contributions.

Using a three-dimensional virtual simulation of the birth process, they were able to show that the space in the chimpanzee pelvis is actually just as tight as it is in humans. Interestingly, after a detailed shape analysis, they also found that female chimpanzees have a more spacious pelvis than males, especially the smaller females, providing evidence of adaptations to deal with these space limitations.

The researchers also show that the great apes appear to trend towards humans in how neurologically immature, or how secondarily altricial their infants are compared to monkeys—again surprisingly similar to humans, although to a lesser magnitude.
Based on these intriguing parallels, the researchers propose a new hypothesis that the obstetrical dilemma developed gradually and became increasingly exacerbated over the course of evolution. This contradicts the previous theory that our long and difficult births emerged abruptly with the enlargement of the brain in Homo erectus.
The increase in body size in the ancestors of the great apes made their pelvis stiffer, which limited the ability of their ligaments to stretch during birth. In early hominins, the upright gait also led to a twisted bony birth canal, which required complex movements of the fetal head. This mechanism, rather than the narrowness of the birth canal, is likely the main cause of the difficult birth process in humans, the researchers argue.
The study shows that the remarkably complex human birth process is the result of gradual compromises during hominoid evolution. The difficult birth and the neurological immaturity of our newborns, with the long learning phase that follows, are a prerequisite for the evolution of our intelligence. At the same time, we humans are only at one extreme—we are not unique among primates, say the researchers.

Nicole M. Webb et al, Gradual exacerbation of obstetric constraints during hominoid evolution implied by re-evaluation of cephalopelvic fit in chimpanzees, Nature Ecology & Evolution (2024). DOI: 10.1038/s41559-024-02558-7

Part 2

Comment by Dr. Krishna Kumari Challa on October 24, 2024 at 9:48am

Study shows birth is a tight squeeze for chimpanzees, too

According to a new study, chimpanzees, like humans, must contend with a confined bony birth canal when giving birth. In humans, the problem is exacerbated by our unique form of upright walking, since this led to a twisting of the bony birth canal, while the fetal head grew larger. The obstetrical dilemma therefore evolved gradually over the course of primate evolution rather than suddenly in humans as originally argued.

The birth process in chimpanzees and other great apes is generally considered to be easy. This is usually attributed to a relatively large pelvis and the small head of their newborn. In contrast, human childbirth is both more complex and riskier when compared to other mammals.

According to the original obstetrical dilemma hypothesis, our birth difficulty stems from a conflict that arose during human evolution between adaptations in the pelvis for upright walking and an increase in our infants' brain size.

On the one hand, the pelvis shortened to improve balance while moving bipedally, while the baby's larger head still had to fit through the birth canal. As a solution to this dilemma, the shape of the pelvic bones differs between the sexes (with females having larger dimensions despite smaller body sizes), and human babies are born more neurologically immature than other primates, so that brain growth is delayed to the postnatal period.

An international team of researchers simulated birth in chimpanzees and humans and quantified the space between the bony birth canal and the fetal head. The work is published in the journal Nature Ecology & Evolution.

The study shows that narrow birth canals in relation to the infant head size are not unique to humans. Accordingly, the obstetrical dilemma hypothesis, which had previously been explained solely by the development of bipedalism and the size of the human brain, did not suddenly appear during the development of modern humans, but rather developed gradually over the course of primate evolution—and then intensified in humans, thus explaining the high rates of birth complications observed today.

Part 1

Comment by Dr. Krishna Kumari Challa on October 24, 2024 at 8:29am

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