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Comment by Dr. Krishna Kumari Challa on February 8, 2025 at 10:26am

Common bacterial infection may trigger lung transplant rejection

A large team of surgeons and organ transplant researchers affiliated with multiple institutions  has found an association between lung transplant patients who become infected with the bacteria Pseudomonas aeruginosa and rejection of the transplanted lung.

In their study published in the journal Science Translational Medicine, the group analyzed lung transplant case histories looking for patients with P. aeruginosa and lung rejection.  Other researchers have published a Focus piece in the same journal issue outlining the work.

The relief that patients with sick lungs experience after a lung transplant is often quickly displaced by fear of their body rejecting the new lungs despite immunosuppressive drugs. Lung transplantation has one of the lowest rates of success of all organ transplants. One of the team members noticed that many patients who experienced lung rejection also had a P. aeruginosa infection.

The team wondered if such infections played a role in transplant rejections. To find out, they analyzed patient case histories and found the rate to be higher than expected. This prompted them to conduct experiments with lab mice.

In their lab experiments, otherwise healthy lab mice were infected with P. aeruginosa and were then given new lungs from another mouse. As the team monitored their progress, they found that the test mice infected with P. aeruginosa experienced bacterial spread to lymphoid tissue, where the infection killed CD4+ cells. That led to growth in the number of B cells expressing a protein called CXCR3, which were sensitive to antigens in the donated lungs. As a result, the B cells produced donor-specific antibodies, which led to rejection of the lungs.

The team also found that giving the test mice drugs that blocked the expression of CXCR3 by the B cells inhibited the mechanism that led to rejection, allowing the mice to keep their new lungs. Thus, the team not only found a possible association between P. aeruginosa infections and rejection of transplanted lungs, but a possible solution for the problem.

Fuyi Liao et al, Pseudomonas aeruginosa infection induces intragraft lymphocytotoxicity that triggers lung transplant antibody-mediated rejection, Science Translational Medicine (2025). DOI: 10.1126/scitranslmed.adp1349

Idaira M. Guerrero-Fonseca et al, No tolerance for Pseudomonas in lung transplants, Science Translational Medicine (2025). DOI: 10.1126/scitranslmed.adu6563

Comment by Dr. Krishna Kumari Challa on February 7, 2025 at 1:47pm

Exactly what may be in the air depends on the fuels that fed the fire. Smoke from burning vegetation is full of fine particles and chemicals, including ozone, sulfur dioxide, polycyclic aromatic hydrocarbons and other volatile compounds that can be hazardous to health.

Increasingly, urban areas are burning too, especially as development snuggles up next to wildlands. So heavy metals are another health worry.

Urban wildfires represent a unique challenge because of the types of pollutants that are generated.
When buildings and automobiles burn, heavy metals, such as lead and copper, get dispersed. Older homes may release asbestos fibers. Plastics and electronics give off noxious chemicals and metals. All of that can contaminate air, soil and water.
Some worry that the chemicals used to fight the fire pose a risk, too. Among the many iconic images of the LA fires were low-flying planes dumping fire retardants that painted neighborhoods red.
But the main component of fire retardant “is ammonium phosphate, which is basically just fertilizer,” say the experts. “The red color comes from iron oxide, which is more or less rust.” Gum or other thickeners may be added. Those are “not so harmful,” they say.

Source: https://www.sciencenews.org/article/toxic-danger-lurk-burn-los-ange...

Part 2

Comment by Dr. Krishna Kumari Challa on February 7, 2025 at 1:44pm

Toxic dangers lurk in LA, even in homes that didn’t burn

Houses still standing after the LA fires may release dangerous chemicals indoors for months.

Even as firefighters douse the deadly LA wildfires, a more insidious danger remains. Chemicals from the ashy residue of thousands of burned homes and cars, scorched plastic pipes and even lifesaving fire retardants have blanketed parts of the region.

And that may jeopardize the immediate health of people living near burn zones for months to come. Long-term health consequences are also possible.

Wildfires’ aftermath may expose people to toxic chemicals and harmful particles in the air and water both outside and inside their homes, experts warn.

Ash, soot and other pollutants that settle out of smoke may get stirred up and resuspended by wind and as people move about. These emissions are not necessarily captured by the regional air quality monitoring.

So even if your city’s air “looks good or healthy or green, that doesn’t necessarily indicate that the air quality is good around your home.” That’s especially a problem for those living close to burned areas but may be an issue kilometers away, too.

Part 1

Comment by Dr. Krishna Kumari Challa on February 7, 2025 at 12:43pm

Why some heavy drinkers develop advanced liver disease, while others do not

Why do some people who consume a few glasses of alcohol a day develop advanced liver disease while others who drink the same amount don't? The answer may lie in three common underlying medical conditions, according to a new study published in Clinical Gastroenterology and Hepatology from Keck Medicine of USC. The research found that heavy drinkers with either diabetes, high blood pressure or a high waist circumference are as much as 2.4 times more likely to develop advanced liver disease.

The results identify a very high-risk segment of the population prone to liver disease and suggest that preexisting health issues may have a large impact on how alcohol affects the liver.

Diabetes, high blood pressure and a high waist circumference (35 inches for women; 40 inches for men), which is associated with obesity, belong to a cluster of five health conditions that influence an individual's risk for heart attack and stroke known as cardiometabolic risk factors.

Cardiometabolic risk factors have been linked to the buildup of fat in the liver (also known as metabolic dysfunction-associated steatotic liver disease), which can lead to fibrosis, or scarring of the liver.

Alcohol also causes fat buildup in the liver.

Researchers discovered that heavy drinkers with either diabetes or a high waist circumference were 2.4 times more likely to develop advanced liver disease and those with high blood pressure 1.8 times more likely.

They found that the other two cardiometabolic risk factors—high triglycerides (elevated levels of a type of fat in the blood) and low HDL (high-density lipoprotein or "good" cholesterol) had less significant correlations to liver disease.

 Brian P. Lee et al, Association of Alcohol and Incremental Cardiometabolic Risk Factors with Liver Disease: A National Cross-Sectional Study, Clinical Gastroenterology and Hepatology (2025). DOI: 10.1016/j.cgh.2025.01.003

Comment by Dr. Krishna Kumari Challa on February 7, 2025 at 12:02pm

While the cerebral cortex has long been considered the brain's primary center for learning, memory and behavioral flexibility, we found the subcortical vLGN and not the visual cortex actually stores these crucial memories. This neural pathway can provide a link between cognitive neocortical processes and 'hard-wired' brainstem-mediated behaviors, enabling animals to adapt instinctive behaviors.
The researchers also uncovered the cellular and molecular mechanisms behind this process. Learning occurs through increased neural activity in specific vLGN neurons, triggered by the release of endocannabinoids—brain-internal messenger molecules known to regulate mood and memory.

This release decreases inhibitory input to vLGN neurons, resulting in heightened activity in this brain area when the visual threat stimulus is encountered, which suppresses fear responses.
The implications of this discovery extend beyond the laboratory.
These findings could also help advance our understanding of what is going wrong in the brain when fear response regulation is impaired in conditions such as phobias, anxiety and PTSD. While instinctive fear reactions to predators may be less relevant for modern humans, the brain pathway we discovered exists in humans too.

This could open new avenues for treating fear disorders by targeting vLGN circuits or localized endocannabinoid systems.

Sara Mederos et al, Overwriting an instinct: Visual cortex instructs learning to suppress fear responses, Science (2025). DOI: 10.1126/science.adr2247. www.science.org/doi/10.1126/science.adr2247

Part 2

Comment by Dr. Krishna Kumari Challa on February 7, 2025 at 12:00pm

Scientists discover brain mechanism that helps overcome fear

Researchers have unveiled the precise brain mechanisms that enable animals to overcome instinctive fears. Published in Science, the study in mice could have implications for developing therapeutics for fear-related disorders such as phobias, anxiety and post-traumatic stress disorder (PTSD).

The researchers mapped out how the brain learns to suppress responses to perceived threats that prove harmless over time.

Humans are born with instinctive fear reactions, such as responses to loud noises or fast-approaching objects. However, we can override these instinctive responses through experience—like children learning to enjoy fireworks rather than fear their loud bangs. Scientists are trying  to understand the brain mechanisms that underlie such forms of learning.

Using an innovative experimental approach, the research team studied mice presented with an overhead expanding shadow that mimicked an approaching aerial predator. Initially, the mice sought shelter when encountering this visual threat.

However, with repeated exposure and no actual danger, the mice learned to remain calm instead of escaping, providing researchers with a model to study the suppression of fear responses.

Based on previous work , the team knew that an area of the brain called the ventrolateral geniculate nucleus (vLGN) could suppress fear reactions when active and was able to track knowledge of previous experience of threat. The vLGN also receives strong input from visual areas in the cerebral cortex, and so the researchers explored whether this neural pathway had a role in learning not to fear a visual threat.

The study revealed two key components in this learning process: 1) specific regions of the visual cortex proved essential for the learning process, and 2) a brain structure called the ventrolateral geniculate nucleus (vLGN) stores these learning-induced memories.

found that animals failed to learn to suppress their fear responses when specific cortical visual areas were inactivated. However, once the animals had already learned to stop escaping, the cerebral cortex was no longer necessary.

The new results challenge traditional views about learning and memory.

Part 1

Comment by Dr. Krishna Kumari Challa on February 7, 2025 at 11:50am

Mercury content in tuna can be reduced with new packaging solution

According to the World Health Organization (WHO), mercury is one of the ten most harmful chemicals for humans. Exposure can damage the central nervous system, with fetuses and young children being particularly sensitive to the effects. That is why dietary recommendations for pregnant women advise caution with tuna consumption.

Fish is a high-quality source of protein, containing omega-3 fatty acids and many other beneficial nutrients. However, the accumulation of toxic mercury also makes fish consumption a concern, of which tuna is particularly susceptible.

Researchers have come up with a novel approach to packaging canned tuna infused in a water-based solution of amino acid cysteine. It was shown to remove up to 35% of the accumulated mercury in canned tuna, significantly reducing human exposure to mercury via food. The research is published in the journal Global Challenges.

The concept of so-called active packaging is to develop materials, like a liquid inside a can, that interacts with food during storage to increase the shelf life.

This study shows that there are alternative approaches to addressing mercury contamination in tuna, rather than just limiting consumption. 

In the study, the researchers discovered that the greater the surface area of fish flesh in contact with the cysteine solution, the higher the mercury uptake. The highest value of mercury reduction, 35%, was reached when testing canned minced tuna, from regular grocery stores. They also discovered a maximum threshold of two weeks, after which no further changes occurred.

In the current study, however, the researchers did not observe any noticeable changes in appearance or smell of the tested fish samples. Cell-based assays have also proven the safety of the developed technology.

Przemysław Strachowski et al, New Insight into Mercury Removal from Fish Meat Using a Single‐Component Solution Containing cysteine, Global Challenges (2024). DOI: 10.1002/gch2.202400161

Comment by Dr. Krishna Kumari Challa on February 7, 2025 at 10:01am

Air pollution clouds the mind and makes everyday tasks challenging, researchers discover

People's ability to interpret emotions or focus on performing a task is reduced by short-term exposure to particulate matter (PM) air pollution, potentially making everyday activities, such as the weekly supermarket shop, more challenging, a new study reveals.

Scientists discovered that even brief exposure to high concentrations of PM may impair a person's ability to focus on tasks, avoid distractions, and behave in a socially acceptable manner.

Researchers exposed study participants to either high levels of air pollution—using candle smoke—or clean air, testing cognitive abilities before and four hours after exposure. The tests measured working memory, selective attention, emotion recognition, psychomotor speed, and sustained attention.

Publishing their findings on 6 Feb in Nature Communications, researchers  reveal that selective attention and emotion recognition were negatively affected by air pollution—regardless of whether subjects breathed normally or only through their mouths.

The experts suggest that inflammation caused by pollution may be responsible for these deficits, noting that while selective attention and emotion recognition were affected, working memory was not. This indicates that some brain functions are more resilient to short-term pollution exposure.

 Acute particulate matter exposure diminishes executive cognitive functioning after four hours regardless of inhalation pathway, Nature Communications (2025).

Comment by Dr. Krishna Kumari Challa on February 6, 2025 at 11:23am

Antibiotic resistance can spread unpredictably into the environment, living on mineral surfaces

Imagine one of world's many picturesque beaches, the waves lapping against the shore, the golden sand and the smooth pebbles. That sounds like a beautiful moment in time. But under the surface, there is more to the story.

A new study, published in Science of The Total Environment,  shows that the sand on that beach may contain antibiotic resistant DNA. Flow and currents in rivers, lakes, streams and the sea, suspend and move mineral particles making it possible for suspended DNA to attach and travel long distances.

The DNA that codes for antibiotic resistance may have been carried into the environment by wastewater from hospitals or farming. If left alone in the water column, the DNA will degrade fast, but if it binds to bypassing mineral surfaces the DNA can be stabilized and survive. Deposited minerals can thus act as a sort of gene library carrying genes from one environment to another, and this may cause antibiotic resistance to spread.

Even though the DNA is bound to the particles, local bacteria can incorporate the DNA and become resistant. Once incorporated, the resistance can spread rapidly to neighboring bacteria and to offspring. In this way, antibiotic resistance can spread unpredictably to new environments—even though these bacteria have never seen a high-resistance environment.

According to the new study, the type of mineral plays a large role for how fast bacteria can incorporate mineral-bound DNA and how fast the obtained trait is disseminated throughout a community. In addition, some mineral grains can both up-concentrate and preserve DNA, while others can only carry a few molecules.

The researchers hope to be able to find an antidote of sorts, a mineral compound that can prevent bacteria from incorporating the DNA or the DNA from spreading in biofilm.

Saghar Hendiani et al, Reconciling the role of mineral surfaces for bacterial evolution: Importance of minerals in the dissemination of antibiotic resistance, Science of The Total Environment (2025). DOI: 10.1016/j.scitotenv.2024.178301

Comment by Dr. Krishna Kumari Challa on February 6, 2025 at 11:16am

Active agent against cancer metastasis discovered: Adhibin prevents migration and attachment to other cells

Every cell in the body normally has its fixed place as part of a tissue structure. Except for a few cell types, such as blood or immune cells. But cancer cells also cross established boundaries, grow into the surrounding tissue and multiply. And they can detach from the cell structure and spread via the blood or lymphatic vessels to other areas of the body, where they attach to new cells and form metastases.

The changes that cancer cells undergo to metastasize are not yet fully understood. Rho (Ras-homologous) GTPases apparently play an important role. These proteins process signals within cells and regulate, among other things, growth, differentiation into the genetically predetermined cell type and cell migration.

Rho GTPases are molecular switches that switch between an active and an inactive state by binding to the phosphate compounds GTP and GDP. GTP corresponds to the 'on' position of the switch and starts the molecular biological processes, while GDP corresponds to the 'off' position and stops them.

A balancing act for the cell: if these Rho proteins are too numerous or too active due to genetic changes, they can cause serious damage to cellular growth and differentiation processes and trigger cancer, for example.

A research team has now found a substance that intervenes in a specific step of the complex Rho signaling pathways and not only prevents tumor cells from forming solid cell clusters but also from actively migrating.

This intervention can be used to prevent the formation of metastases. The results of the research have been published in Nature Communications.

Despoina Kyriazi et al, An allosteric inhibitor of RhoGAP class-IX myosins suppresses the metastatic features of cancer cells, Nature Communications (2024). DOI: 10.1038/s41467-024-54181-6

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