Comment

Comment by Dr. Krishna Kumari Challa on December 5, 2023 at 6:55am

Toxic chemicals in  whales and dolphins are exceeding safe limits

Almost half of marine mammals around the UK are being poisoned by banned chemicals.

The compounds, once used in pesticides, flame retardants and coolants, are having significant impacts on the health and reproduction of the animals.

The UK's whales and dolphins are full of toxins—and it might only get worse.

Despite many being banned almost 20 years ago, levels of persistent organic pollutants (POPs) remain high in the oceans. In fact, these chemicals may breach safe limits in as many as half of all marine mammals living around the UK, based on a new study of stranded animals.

While the researchers found that levels of six key POPs are declining, they're concerned that the chemicals currently contained in coastal landfill sites could increasingly leak out as flooding, extreme weather and coastal erosion are enhanced by climate change.

What is alarming is this can happen anywhere in the world.

Rosie S. Williams et al, Spatiotemporal Trends Spanning Three Decades Show Toxic Levels of Chemical Contaminants in Marine Mammals, Environmental Science & Technology (2023). DOI: 10.1021/acs.est.3c01881

Comment by Dr. Krishna Kumari Challa on December 5, 2023 at 6:47am

Brain implants revive cognitive abilities long after traumatic brain injury in clinical trial

A lady in her final semester of college, planning to apply to law school, when she suffered a traumatic brain injury in a car accident. The injury so compromised her ability to focus she struggled in a job sorting mail.

She couldn't remember anything . Her left foot dropped, so she'd trip over things all the time. She was always in car accidents. And she had no filter—she'd get pissed off really easily.

Her parents learned about research being conducted at Stanford Medicine and reached out; she was accepted as a participant. In 2018, physicians surgically implanted a device deep inside her brain, then carefully calibrated the device's electrical activity to stimulate the networks the injury had subdued. The results of the clinical trial were published Dec. 4 in Nature Medicine. She noticed the difference immediately. When she was asked to list items in the produce aisle of a grocery store, she could rattle off fruits and vegetables. Then a researcher turned the device off, and she couldn't name any. Since the implant she hadn't  had any speeding tickets she said. She doesn't trip anymore. She can remember how much money is in her bank account. She  wasn't able to read earlier, but after the implant she bought a book, 'Where the Crawdads Sing,' and loved it and remembered it. And she doesn't have that quick temper." For her and four others, the experimental deep-brain-stimulation device restored, to different degrees, the cognitive abilities they had lost to brain injuries years before. The new technique, developed by Stanford Medicine researchers and collaborators from other institutions, is the first to show promise against the long-lasting impairments from moderate to severe traumatic brain injuries.

Nicholas Schiff, Thalamic deep brain stimulation in traumatic brain injury: a phase 1, randomized feasibility study, Nature Medicine (2023). DOI: 10.1038/s41591-023-02638-4. www.nature.com/articles/s41591-023-02638-4

Comment by Dr. Krishna Kumari Challa on December 4, 2023 at 7:05am

The brain sizes of our ancestors, the Australopiths, were similar to those of chimpanzees (Pan troglodytes) and bonobos (Pan paniscus). The human lineage's brain expansion accelerated with Homo's emergence and continued through Homo sapiens and Homo neanderthalensis.

How did our ancestors, with brains about the size of chimpanzees, manage to harness the power of external fermentation?

Researchers suggest that hominids with lower cognitive abilities and smaller brains may have adapted to fermentation much earlier than proposed alternative alternative explanations for this gut-to-brain energy redirection, like animal hunting and fire-based cooking.
Fermentation has many advantages associated with cooked foods, such as softer textures, increased caloric content, improved nutrient absorption, and defense against harmful microorganisms.
The researchers emphasize the need for empirical research to support or refute their hypothesis, such as microbiological studies, comparative analyses, and genetic and genomic investigations.

https://www.nature.com/articles/s42003-023-05517-3

Part 2

**

Comment by Dr. Krishna Kumari Challa on December 4, 2023 at 7:02am

Food Preserving Technique May Have Sparked Human Brain Growth: Researchers

Researchers propose that a taste for fermented morsels may have triggered a surprising jump in the growth rate of our ancestors' brains.

In fact, a shift from a raw diet to one that included food items already partially broken down by microbes may have been a crucial event in our brain's evolution, according to a perspective study by evolutionary neuroscientists.

Human brains have tripled in size over the last two million years of evolution, while human colons have shrunk by an estimated 74 percent, suggesting a reduced need to break down plant-derived food internally.
We know the timeline and extent of human brain expansion, but the mechanisms allowing energy to be directed to this expansion are more complex and somewhat debated.

The study authors lay out their "external fermentation hypothesis" which shows our ancestors' metabolic circumstances for selective brain expansion may have been set in motion by moving intestinal fermentation to an external process, perhaps even experimenting with preserved foods not unlike the wine, kimchi, yoghurt, sauerkraut, and other pickles we still eat today.
The human gut microbiome acts like a machine for internal fermentation, which boosts nutrient absorption during digestion. Organic compounds are fermented into alcohol and acids by enzymes, usually produced by the bacteria and yeasts that live in parts of our digestive system such as our colon.
Fermentation is an anaerobic process, meaning it doesn't require oxygen, so similar to the process in our guts, it can occur in a sealed container. The process produces energy in the form of adenosine triphosphate (ATP), which is an essential source of chemical energy that powers our metabolism.

The researchers argue it's possible that culturally passed-down ways of handling or storing food encouraged this function to be externalized.

Externally fermented foods are easier to digest and contain more available nutrients than their raw equivalents. And since there's less for the colon to do if the food is already fermented, the organ's size could reduce over time while still potentially leaving energy available for brain growth.
Part 1

Comment by Dr. Krishna Kumari Challa on December 3, 2023 at 2:34pm

Dolphins can detect electrical fields

Two captive bottlenose dolphins (Tursiops truncatus) have now proved to researchers at the University of Rostock and Nuremberg Zoo in Germany that they can reliably sense weak electric fields in the water with their long snouts.

The discovery hints at the possibility that some marine mammals really can sniff out the electric currents of small prey buried in the sand. They might even use the skill to sense Earth's magnetic field.

To date, only one other 'true' placental mammal on Earth has been found to possess electroreceptors. Little more than a decade ago, scientists demonstrated that the common Guiana dolphin (Sotalia guianensis) evolved its own unique system of electroreception – one that is inherently different to fish, amphibians, and monotremes, like platypuses and echidnas.

Experiments now suggest that adult bottlenose dolphins and Guiana dolphins can both do something oddly similar with a line of sensitive pores on their snouts, called vibrissal crypts. These little holes used to hold juvenile whiskers, and they are extremely sensitive.

In experiments, bottlenose dolphins were able to use these ex-whisker pits to sense very weak electric fields as low as 2.4 and 5.5 microvolts per centimeter – a detection threshold that the researchers say is "in the same order of magnitude as those in the platypus" and also similar to Guiana dolphins.

https://journals.biologists.com/jeb/article/226/22/jeb245845/334721...

Comment by Dr. Krishna Kumari Challa on December 3, 2023 at 2:29pm

New discovery: Stunning River of Stars Flowing Through Space

A stunning river of stars has been spotted flowing through the intergalactic space in a cluster of galaxies about 300 million light years away.

Such bridges are known as stellar streams; and, at a length of 1.7 million light-years, the newly named Giant Coma Stream is the longest we've ever seen. And that's not all: the faint river is the first of its kind ever seen outside of a galaxy.

https://www.aanda.org/articles/aa/full_html/2023/11/aa46780-23/aa46...

Comment by Dr. Krishna Kumari Challa on December 2, 2023 at 10:24am

By comparing "normal" placentas with placentas from pregnancies where patients suffered from preeclampsia, investigators demonstrated that preeclampsia was associated with higher levels of cellular stresses in the STB layer on the placenta. Additionally, the researchers found a hyperactive level of activity of the Gαq protein known to play a role in transmitting signals related to the levels of several hormones present in excessive amounts during preeclampsia.

So, can preeclampsia be prevented? While today the answer is no, MCW scientists now are one step closer with these experimental results. And they are continuing to work as a team to achieve this goal through additional studies.

Megan Opichka et al, Mitochondrial-Targeted Antioxidant Attenuates Preeclampsia-Like Phenotypes Induced by Syncytiotrophoblast-Specific Gαq Signaling, Science Advances (2023). DOI: 10.1126/sciadv.adg8118. www.science.org/doi/10.1126/sciadv.adg8118

Part 2

Comment by Dr. Krishna Kumari Challa on December 2, 2023 at 10:23am

New research suggests cellular stress in the placenta may be possible cause of preeclampsia

Preeclampsia is a mysterious condition that occurs in about one of 10 pregnancies without any early warning signs. After 20 weeks or more of normal blood pressure during the pregnancy, patients with preeclampsia will begin to experience elevated blood pressure and may also have increased levels of protein in their urine due to hypertension reducing the filtering power of the kidneys. Prolonged hypertension due to preeclampsia can lead to organ damage and life-threatening complications for mothers and fetuses.

There is no cure for the underlying causes of preeclampsia, so physicians focus on managing and monitoring patients' blood pressure to allow for as close to a full-term gestation as possible. With severe disease, pre-term deliveries are necessary.

For those who get it earlier on, it can be terrifying and life-changing, potentially including a long hospital stay before delivery and significant supportive care for the infant in the NICU afterwards.

Now scientists have published results on a study of one of the emerging theories for what causes preeclampsia in Science Advances.

The experiments focus on a particular layer of cells of the placenta called the syncytiotrophoblast (STB), which is a key part of the barrier between the mother and developing fetus. This blockade helps keep a mother's fully formed immune system from reacting to the fetus and potentially responding as if the fetus was a foreign threat such as a viral or bacterial invader.

The barrier also works in reverse to keep the fetus's growing immune system from reacting to its mother's cells and tissues. The study's authors investigated the hypothesis that an abnormal amount of cellular and molecular stresses to the STB can damage the placenta and lead to preeclampsia.

Part 1

Comment by Dr. Krishna Kumari Challa on December 2, 2023 at 9:36am

As dengue expands beyond the global 'dengue belt,' scientists dispel conventional wisdom about the disease

Unknowns, dangers and surprises persist about dengue viral infection and now an assumption once accepted as conventional wisdom about immunity to the mosquito-borne disease may be incorrect.

Dengue is a devastating viral infection transmitted to humans through the bite of Aedes aegypti mosquitoes—flying hypodermic needles that descend prolifically during significant outbreaks. Many dengue epidemics tend to occur in urban settings, scientists say. Dengue viral infection can cause a severe headache, high fever, nausea, vomiting, swollen glands, and rash. Still, and perhaps most surprisingly, many people who are infected have no symptoms at all. In rare cases, however, dengue disease can be fatal.

New research involving epidemiological models and data from more than 4,400 people in Nicaragua suggests that it's time immunologists developed a new framework to understand population immunity to dengue. For decades, it was believed that once you were infected with dengue virus, the immunity lasted for life. The dogma persisted in the face of observational data, which found that people who were previously infected were more susceptible to severe dengue if infected again.

But an international collaborative group of researchers has now conclusively shown that immunity not only wanes, it tends to wax and wane—a discovery that reveals dengue infection to be far more complex than previously thought.

According to them, Infection with multiple dengue virus serotypes is thought to induce enduring protection against dengue disease. However, long-term antibody waning has been observed after repeated dengue infection. The waning of antibodies inevitably was followed by a boosting of antibodies when the next epidemic came along.

This discovery allowed the construction of a new model that best describes population vulnerability to dengue infection, especially amid the known periodicity—the cyclic nature—of dengue outbreaks.

When it comes to dengue, people are not permanently immune but susceptible to infection, then immune and ultimately susceptible again. Hence, the researchers  newly proposed a model: "susceptible-infected-recovered-susceptible."

Rosemary A. Aogo et al, Effects of boosting and waning in highly exposed populations on dengue epidemic dynamics, Science Translational Medicine (2023). DOI: 10.1126/scitranslmed.adi1734

Comment by Dr. Krishna Kumari Challa on December 1, 2023 at 12:18pm

Brain waves usually found in sleep can protect against epileptic activity

Slow waves that usually only occur in the brain during sleep are also present during wakefulness in people with epilepsy and may protect against increased brain excitability associated with the condition, finds a new study by researchers.

The researchers examined electroencephalogram (EEG) scans from electrodes in the brains of 25 patients with focal epilepsy (a type of epilepsy characterized by seizures arising from a specific part of the brain), while they carried out an associative memory task.

The electrodes had been placed in the patients' brains to localize abnormal activity and inform surgical treatment.

During the task, participants were presented with 27 pairs of images that remained on a screen for six seconds. The images were in nine groups of three—each group featuring a picture of a person, a place and an object. In each case, participants had to remember which images had been grouped together. EEG data were recorded continuously throughout the task.

After reviewing the EEG data, the team found that the brains of people with epilepsy were producing slow waves—lasting less than one second—while they were awake and taking part in the task.

The occurrence of these "wake" slow waves increased in line with increases in brain excitability and decreased the impact of epileptic spikes on brain activity.

In particular, there was a decrease in the "firing" of nerve cells, which the researchers say could protect against epileptic activity.

Wake slow waves in focal human epilepsy impact network activity and cognition, Nature Communications (2023). DOI: 10.1038/s41467-023-42971-3

• ‹ Previous
• 1
• …
• 230
• 231
• 232
• 233
• 234
• …
• 1004
• Next ›
• Page