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Comment by Dr. Krishna Kumari Challa on Tuesday

Heat-trapping gas once frozen in Arctic ground is slowly leaking and warming the planet
Arctic permafrost thaw releases methane and carbon dioxide from decomposing organic matter, amplifying global warming. These emissions are projected to add about 0.25°C of warming by 2100, beyond fossil-fuel-driven warming. Thaw also destabilizes ground, threatening buildings, roads and pipelines.

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How can the same El Niño cause drought in one part of the world and floods in another?

El Niño weakens trade winds, shifting warm water and rainfall eastward and favouring wetter conditions in the eastern Pacific and drought in the western Pacific. Changes in atmospheric heating, winds and other oceans extend these effects globally. El Niño shifts weather probabilities, but local systems can still produce opposing extremes.

original article.

Comment by Dr. Krishna Kumari Challa on Tuesday

High blood pressure can accelerate osteoarthritis joint damage via a newly identified hormone pathway
For millions of people, osteoarthritis slowly breaks down the joints, bringing pain, swelling and stiffness that make free movement harder with time. It is largely a condition of age, with 73% of those living with it older than 55. For years, the wear and tear that comes with aging and physical trauma was considered a major driver of the disease. A recent study published in Science, however, points to a metabolic disease that is also highly common among this demographic as a contributing factor in osteoarthritis progression.
A look at national health data from 36,820 Korean adults ages 45 and older revealed that high blood pressure was linked to osteoarthritis, with stronger associations in more severely damaged knees.

In mouse models, the researchers saw that hypertension actively drives joint breakdown in aging or injured joints. The damaging mechanism was coordinated by a brain hormone and a hormone receptor found in joints. These two components created conditions that ramped up destructive enzymes that break down cartilage. At the same time, they suppressed the production of cartilage components, such as collagen and aggrecan, that joints need to repair themselves.
To test cause and effect in living organisms, the team performed surgery on male mice to simulate mechanical joint wear and tear. They cut microscopic knee sections and stained them with a dye to measure changes in knee and bone structures.
Gene profiling experiments showed that high blood pressure increases blood levels of a brain hormone called arginine vasopressin (AVP), which travels through the bloodstream and leaks into the joint fluid. Healthy joint cartilage has little to no place for this hormone to bind, but mechanical injury or aging changes that.

Damaged cartilage starts producing a receptor called AVPR1A, which binds the hormone AVP and switches on a gene regulator called NR4A3. This sets off a damaging chain reaction. Cells begin producing excessive amounts of enzymes that break down cartilage while simultaneously reducing the proteins needed to build and maintain it.

The researchers also compared damaged and healthy knee cartilage and joint fluid collected during human total knee replacement surgeries. The damaged human cartilage had higher levels of AVPR1A receptors and a biomarker of the hormone vasopressin, which is responsible for increased blood pressure.
They also found that removing the AVPR1A gene or injecting a vasopressin receptor antagonist called relcovaptan directly into the knee joint prevented high blood pressure from accelerating cartilage loss. However, treating mice with standard blood pressure medication did not improve the condition of the cartilage.

This study uncovers the biological mechanisms linking hypertension to accelerated osteoarthritis progression.

Su-Jin Kim et al, Hypertension fuels osteoarthritis through neuroendocrine signaling, Science (2026). DOI: 10.1126/science.aed8207

Chunyi Wen et al, Osteoarthritis as a vascular disease, Science (2026). DOI: 10.1126/science.ael3784

Comment by Dr. Krishna Kumari Challa on Tuesday

When unsure of the rule, people remembered the 'irrelevant' feature better. The value of the ignored feature pushed choices in a consistent direction.

Cheng Xue et al, Feature interference underlies a neuronal basis for the behavioral cost of task uncertainty, Nature Neuroscience (2026). DOI: 10.1038/s41593-026-02430-w.

Part 2

Comment by Dr. Krishna Kumari Challa on Tuesday

Irrelevant visual details interfere with decisions under uncertainty, brain research shows

Cognitive flexibility, the ability to adjust one's way of thinking or behavior as a situation changes, is known to gradually decline with age or due to some conditions, including Alzheimer's disease, Parkinson's disease, schizophrenia and substance use disorders. One aspect of cognitive flexibility is being able to switch between different tasks without becoming distracted and losing focus.
Researchers recently carried out a study involving both people and monkeys to understand how suddenly changing the rules of a task influences how the brain processes available information. Their findings, presented in a paper published in Nature Neuroscience, suggest that uncertainty increases the likelihood that irrelevant visual features will interfere with decision-making.

Even healthy young people feel stretched when they juggle several tasks, and psychology research shows that we become slower and more error-prone right after a switch.
So researchers wanted to find a possible neuronal explanation for why switching between different tasks can reduce performance. Specifically, they wished to understand what brain changes are associated with mistakes during basic perceptual judgments when people and nonhuman primates are unsure about what task they should be performing.
To shed light on these neural changes, the researchers conducted experiments involving humans and monkeys. Both species were shown images as they performed one of two visual tasks.
The tasks required participants to focus on one feature of an image while ignoring another. The rule governing which visual feature mattered changed during the experiment, requiring participants to determine what task to perform at different times.

Their performance on the task they chose to do indeed became worse.
To find out why the brain makes such mistakes, they first taught a model to err in the same way. Instead of training an artificial neural network to perform the task well, they trained it to reproduce the animals' actual choices, mistakes included. The network then became a specimen they could take apart to generate precise hypotheses.
After training a machine learning model to reproduce the choices made by monkeys during the experiment, the researchers trained a second model to make correct choices on the same tasks. This allowed them to compare the performance of the two.

Analyzing the model showed that mistakes during task switching are likely driven by the interference of the task-irrelevant information with task-relevant information.
Then they tested the model's predictions with new behavioral experiments in humans, analyses of the neuronal recordings while the animals performed the task, and small artificial perturbations of the neuronal activities in the animals' visual cortex.

The team's findings suggest that the additional mistakes made by both humans and monkeys under uncertainty are not random. Instead, the mistakes appeared to follow a specific pattern, which the team dubbed "feature interference".
When we are unsure which rule applies, the brain holds on to information it should be ignoring.
The brain's representations of different features are not perfectly separate; they sit at an angle to one another. The lingering irrelevant information therefore leaks into the relevant information and biases decisions in a predictable direction.
The results gathered indicate that, under uncertainty, mistakes may not come from a shortage of mental resources. Instead, mistakes could arise, at least in part, when mental representations of different visual features interfere with one another.

Part 1

Comment by Dr. Krishna Kumari Challa on Tuesday

The 2026 Nobel Prize in Physiology or Medicine was awarded to scientists Karl Deisseroth, Georg Nagel and Peter Hegemann for their discoveries underpinning the field of optogenetics, the ability to control genetically modified cells with light.
Optogenetics makes it possible to switch on, or off, the activity of individual nerve cells in a living brain. This method is now being used in laboratories around the world to reveal the brain’s mysteries.

This shows that extraordinary creativity and ability to bridge disciplines have given scientists powerful new tools to unravel the complexities of the human brain, bringing answers to questions once beyond reach and hope to patients and families worldwide.

The hope that the knowledge generated by using optogenetics will lead to new medical treatments has begun to come to fruition. The method has provided greater understanding of the distinguishing features of psychiatric and neurological disorders such as depression, anxiety, schizophrenia, Alzheimer’s disease and Parkinson’s disease.

Researchers have also taken the first steps towards using optogenetics as a medical treatment. In ongoing clinical trials they attempt to restore vision in people who have become blind due to retinitis pigmentosa, a disease that destroys the eye’s rods and cones. When they inserted a channelrhodopsin-like protein in the retina of a blind person, the person regained some vision. Using special glasses emitting light, the person was able to discern and grasp objects on a table.

There are also hopes that optogenetics could improve cochlea implants. Currently, these implants stimulate the auditory nerve using electricity. If it were instead possible to use optogenetics, the implant may be able to activate the auditory nerve with greater precision.

https://www.nobelprize.org/prizes/medicine/2026/popular-information/

Comment by Dr. Krishna Kumari Challa on October 4, 2026 at 11:56am

Nine Patients Received a Personalized Kidney Cancer Vaccine. None Had a Recurrence.
How do you teach the immune system to recognize a cancer cell?

Researchers are taking clues from the tumor itself, selecting unusual protein fragments and putting them into a vaccine. The aim is to help the body recognize that particular patient's cancer.

In a small kidney cancer trial, this approach produced encouraging results. Nine people received an experimental vaccine tailored to their own tumors.

None experienced a recurrence during a median follow-up of roughly three years and four months after surgery.

All nine developed immune responses to the vaccine. In seven, vaccine-reactive T cells could also recognize the patient's own tumour. T cells are immune cells that help identify threats and coordinate or carry out an attack.
But these findings do not yet prove that vaccination prevented the cancer from returning.

With the limited number of patients, we must be cautious with further interpretation.

https://www.nature.com/articles/s41586-024-08507-5

Comment by Dr. Krishna Kumari Challa on October 4, 2026 at 11:13am

Virus nabbed gene from ancient people
The poxvirus molluscum contagiosum virus (MCV) contains two copies of an ancient human gene, which could be helping it to infect people. The gene, BC200, was originally a ‘jumping gene’ — a sequence that could move around in the genome — but has since lost its ability to relocate. Researchers found that the virus acquired BC200 around 150,000 years ago, which suggests that the gene was still mobile relatively recently in human evolutionary history. MCV might use BC200 to keep a host cell’s protein factories active so it can replicate, the team says.

https://www.science.org/doi/10.1126/science.aeh3441

Comment by Dr. Krishna Kumari Challa on October 3, 2026 at 8:48am

No single approach works for everyone, but several options have evidence behind them.

During perimenopause and after menopause, the National Institute for Health and Care Excellence (NICE) recommends considering vaginal estrogen for recurrent UTIs. NICE produces health and care guidance for England and recommends this approach when behavioral and personal hygiene measures have not been effective or are unsuitable. It has some of the strongest evidence among nonantibiotic approaches.
Drinking more water can help people who do not normally drink much. In a trial of 140 premenopausal women who drank less than 1.5 liters (51 fluid ounces) of fluid a day, those asked to add another 1.5 liters (51 fluid ounces) of water averaged 1.7 bladder infections over a year, compared with 3.2 among those who continued their usual intake.

Cranberry products may reduce recurrence for some women, although the evidence varies between studies and formulations. Current guidance from the European Association of Urology advises patients that the evidence remains contradictory and generally low quality.

D-mannose, a type of sugar sold as a dietary supplement, is thought to help prevent UTIs by making it harder for some E. coli bacteria to stick to the bladder lining. It looked promising in smaller studies but failed to prevent infections in a much larger U.K. randomized trial involving 598 women.

For people with recurrent infections, NICE says doctors can consider preventive treatment after any current infection has been treated. Options can include methenamine hippurate, a nonantibiotic urinary antiseptic, or preventive antibiotics. The choice depends on factors including how frequent and severe the infections are, previous urine test results, previous antibiotic use and whether measures such as vaginal estrogen or a single antibiotic dose after an identifiable trigger have helped.

Long-term antibiotic use also needs to be weighed against side effects and antimicrobial resistance, which the World Health Organization describes as a growing threat to global health.

The mini-bladder findings recast a UTI as a disease shaped by interactions between bacteria, bladder tissue, the immune system and the chemical and physical conditions inside the bladder.

Bladder-model study also investigated whether bacteria-killing viruses called bacteriophages, or phages, could help target bacteria persisting in bladder tissue. Phages reduced clusters of bacteria inside bladder cells, but adding them to nitrofurantoin did not consistently clear more bacteria from the bladder tissue than the antibiotic alone.

For someone whose infection keeps coming back, one possible explanation is that a small population of bacteria survived the original treatment and was able to start growing again.

original article.

Part 2

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Comment by Dr. Krishna Kumari Challa on October 3, 2026 at 8:46am

Lab‑grown 'mini‑bladder' helps explain why urinary tract infections keep coming back

UTIs affect more than 400 million people worldwide each year, according to a global analysis of UTI incidence. More than half of adult women will have at least one in their lifetime, and studies suggest around a quarter experience another within six months.

Antibiotics aren't simply failing. New research using a lab-grown human "mini-bladder" suggests part of the answer may lie inside the bladder wall itself.

Most UTIs are caused by a type of Escherichia coli that normally lives harmlessly in the gut. Problems start when bacteria travel up the urethra into the bladder.

A repeat infection can happen in two ways. New bacteria from the gut can make the same journey again, and many recurrences are reinfections. But sometimes bacteria from the original infection appear to survive treatment and later reemerge.
In 3D human bladder models, E. coli survived fosfomycin in deeper tissue in a cell-wall-deficient form and regrew after treatment ended. Concentrated urine weakened tissue barriers, while nitrofurantoin failed to eradicate tissue-associated bacteria in a separate model. These laboratory findings support a possible mechanism of UTI recurrence but do not establish its clinical frequency.
Why women are hit hardest
Anatomy is a major reason women tend to suffer more than men from UTIs. A woman's urethra is much shorter than a man's, so bacteria have a shorter distance to travel before reaching the bladder. The urethral opening is also close to the anus, where gut bacteria live.

Sexual activity and the use of spermicides are also established risk factors for recurrent infection in premenopausal women.

Risk rises again around and after menopause. Falling estrogen changes the tissues of the vagina and urinary tract and is associated with a reduction in protective Lactobacillus bacteria, creating conditions in which UTI-causing bacteria can become more established.
Part 1

Comment by Dr. Krishna Kumari Challa on October 3, 2026 at 8:20am

Inflammation can reactivate 'sleeping' cancer cells hidden in the bone

The spread of cancer from a primary tumour to another place in the body, called metastasis, remains one of the greatest challenges in cancer treatment and is responsible for most cancer-related deaths.
Cancer cells that have moved to another part of the body can stay dormant for years after the original tumour has been treated.
It's a worrying period for people, as they don't know if these metastatic cells will reactivate, leading to a relapse.
Breast cancer cells often spread to the bone marrow, where they can lie dormant for years within the tissue that normally supports the production of new blood cells. These disseminated cancer cells enter a "sleeping" state, which helps them evade the immune system and resist chemotherapy. What causes them to "wake up" is not only a key issue in cancer biology but also a huge challenge to study.

Injuries to the bone like fractures can lead to the growth of metastatic cancer cells hosted in the bone marrow, but the team wanted to establish if more indirect insults throughout the body, such as those caused by injury or infections, could also kick-start tumour development.
So researchers induced intestinal colitis—inflammation in the gut—in the mice with the extramedullary bone hosting dormant metastatic cells. Because the replica bone responds to the immune system, gut inflammation triggered a rapid production of immune cells from the bone.
The bone marrow environment needs to remodel to boost production of new immune cells, and it turned out that this change had a profound effect on the dormant cancer cells. More cancer cells started replicating, which increased the risk of a tumour forming.
In mice with engineered bone tissue, gut inflammation increased immune cell production and HMGB2, promoting reactivation of dormant breast cancer cells. Increased HMGB2 alone stimulated reactivation; it was also present in regions containing dividing cancer cells in human breast and prostate cancer bone samples.
By analyzing which genes were being switched on in the bone cells and the cancer cells, the team showed that a molecule that stimulates cell growth, HMGB2, increased as immune cell production surged, but also promoted the awakening of dormant cancer cells.

Even without inflammation elsewhere in the body, just the increased HMGB2 in the artificial bone was enough to stimulate more cancer cells to activate.
All of these findings suggest that boosting immune cell production in the bone, as part of a normal response to inflammation, comes at the cost of disrupting tumour dormancy, tipping the balance toward reactivation and metastatic growth.
The research suggests that monitoring people in this critical period after remission for infections, inflammation or injury anywhere in the body may indicate whether dormant cells are more likely to reactivate.

Stefania Di Blasio et al, An extramedullary bone model of metastatic dormancy reveals an increased rate of metastatic reactivation upon distant insults, Cell Reports (2026). DOI: 10.1016/j.celrep.2026.118088

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