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Comment by Dr. Krishna Kumari Challa 8 hours ago

HIV enters the brain and doesn't leave, drugs intended to reduce brain inflammation increase virus levels
HIV persists in the brain, where standard antiviral drugs have limited efficacy due to poor penetration of the central nervous system. Attempts to reduce brain inflammation by blocking integrins, specifically alpha-4, inadvertently increased viral loads by reducing killer T cell migration while allowing helper T cells to continue introducing HIV. Precision-targeted immune therapies may be necessary to control HIV-associated neurodegeneration without exacerbating viral persistence.

original article.

Comment by Dr. Krishna Kumari Challa 8 hours ago

Hay fever, antihistamines and the evidence on dementia risk

For millions of people around the world, pollen season means weeks of sneezing, itchy eyes, and a blocked or runny nose. The timing varies depending on where you live and which plants are in flower, but grass pollen is one of the most common triggers.
Hay fever, also known as seasonal allergic rhinitis, is an allergic reaction to airborne pollen. Many people manage their symptoms with antihistamines bought from a pharmacy. But recent headlines have raised a worrying question: could some of the medicines used to relieve hay fever symptoms increase the risk of dementia?

Antihistamines block histamine, a chemical released by the immune system during an allergic reaction. Histamine causes symptoms such as itching, sneezing, and a runny nose.

Older, first-generation antihistamines, such as diphenhydramine and chlorphenamine, are more likely to cause drowsiness. Newer, second-generation antihistamines, such as cetirizine, loratadine, and fexofenadine, are generally less sedating.

Some older antihistamines also reduce the activity of acetylcholine, a chemical messenger involved in attention, learning, and memory. Medicines that block the action of acetylcholine are described as having anticholinergic effects.
These older medicines should be used cautiously, particularly in later life. They can cause drowsiness and concentration problems, increasing the risk of falls. People should also take care when driving if a hay-fever medicine makes them sleepy, as highlighted in recent reports.
Some studies have found an association between prolonged use of medicines with strong anticholinergic effects and a higher risk of dementia. These include some treatments for depression, Parkinson's disease, and bladder problems, as well as certain older antihistamines.

There is a plausible reason for concern: acetylcholine plays an important role in memory and thinking. Some medicines used to treat symptoms of Alzheimer's disease work by increasing the amount of acetylcholine available in the brain. Anticholinergic medicines reduce its activity.
One large observational study found that people with the highest exposure to strong anticholinergic medicines had a greater risk of dementia. But observational studies can identify patterns without proving that one factor causes another. People who take these medicines may differ from those who do not in other ways that affect their dementia risk. Some may have underlying health conditions, while others may have been prescribed medication for symptoms linked to the early stages of dementia.

A 2024 study of people with allergic rhinitis also found that dementia risk appeared to increase with higher cumulative doses of antihistamines, meaning the total amount taken over time. The association was stronger for first-generation medicines but was also seen, to a lesser extent, with newer second-generation antihistamines.

That finding was puzzling since second-generation antihistamines are less likely to cross the blood-brain barrier, the protective boundary separating the bloodstream from the brain. They also tend to have fewer anticholinergic effects.
Prolonged use of first-generation antihistamines with strong anticholinergic effects is associated with an increased risk of dementia, while evidence does not support a similar risk for second-generation antihistamines. Confounding factors, such as allergy severity and inflammation, complicate interpretation of these associations. Newer antihistamines are generally preferred due to fewer side effects and lower dementia risk.

original article.

Comment by Dr. Krishna Kumari Challa 10 hours ago

Excessive bite force does not cause alveolar bone loss but significantly worsens it when combined with periodontitis, report researchers in a new study. While traumatic occlusion has long been suspected to exacerbate periodontitis, the molecular mechanisms behind this link were poorly understood. Now, using mouse models of both conditions separately and combined, the researchers conducted comprehensive gene expression analysis across multiple periodontal tissues, identifying key inflammatory pathways upregulated in bone when both conditions were present.
Periodontitis, or inflammation of the tooth-supporting tissues, is one of the most common chronic diseases worldwide and a leading cause of tooth loss in adults. It develops when bacterial buildup around the teeth triggers persistent inflammation, gradually destroying their supporting bone and tissue structures. While bacterial infection is the primary driver of periodontitis, other factors also influence how severely and quickly the condition progresses. These include lifestyle habits such as alcohol consumption and smoking, autoimmune disorders, and—as researchers have long suspected—the way teeth come together when biting or grinding.

When teeth are repeatedly subjected to abnormal or excessive bite forces, known as "traumatic occlusion," supporting structures come under intense mechanical stress. For decades, dentists and scientists have hypothesized that this overload can worsen periodontitis excessively, so that occlusal adjustment (reshaping of the biting surfaces) is already used in clinical practice as a part of gum disease treatment.
Using advanced imaging techniques, including micro-computed tomography, the team measured bone loss around the teeth. They also performed transcriptome analysis to examine the activity of thousands of genes in gum tissue, bone, and the periodontal ligament shortly after disease induction. This enabled them to capture early changes in gene expression associated with each condition. Additionally, they investigated the effects of long-term traumatic occlusion alone over a period of eight weeks.

Interestingly, mice exposed only to traumatic occlusion did not show significant bone loss, even after prolonged exposure. However, when traumatic occlusion was combined with periodontitis, bone loss became significantly more severe.
This confirms that excessive bite force does not directly cause damage but instead amplifies the destructive effects of existing dysregulation caused by periodontitis.

Yosuke Tsuchiya et al, Traumatic Occlusion Exacerbates Bone Resorption by Modifying Gene Expression in the Bone Tissue of Ligature‐Induced Periodontitis in Mice, Journal of Clinical Periodontology (2026). DOI: 10.1111/jcpe.70112

Part 2

Comment by Dr. Krishna Kumari Challa 10 hours ago

How mechanical stress can accelerate bone destruction in periodontitis
Mechanical stress from excessive bite force alone does not cause alveolar bone loss but significantly accelerates bone destruction when combined with periodontitis. Gene expression analysis in mouse models showed that key inflammatory and bone metabolism pathways are upregulated only when both conditions coexist, indicating that mechanical overload amplifies periodontitis-induced bone loss through enhanced inflammatory signalling.

Part 1

Comment by Dr. Krishna Kumari Challa 10 hours ago

How often do people pass gas?

Flatulence, or farting, is something people often joke about or find embarrassing when it happens unexpectedly. It is, however, an essential bodily function that allows the digestive system to keep pressure within the intestinal tract low and prevents painful stretching of the stomach and intestines. Even though it is normal to fart, it remains unclear what counts as a healthy number.

A study by researchers from the Commonwealth Scientific and Industrial Research Organisation wanted to measure how many times people pass gas in a day. So they designed a mobile phone application, Chart Your Fart, that allowed more than 6,400 Australians to log their farting patterns in real time.

They found that most people, on average, passed gas five times a day, with men doing it more often than women. Flatulence patterns were not the same throughout the day.

They observed a gradual increase that typically peaked between 6 p.m. and 10 p.m., coinciding with the time when people generally consume the most calories and fiber.

When we fart, our body releases a mixture of gases accumulated from two very different origins. The first is the air that sneaks in when you are eating or drinking, and the second is the gases churned out by the billions of bacteria living in the gut during digestion.

The swallowed air is harmless and odorless, but the byproduct of the bacterial breakdown of food contains sulfurous compounds that are responsible for the notorious smell associated with flatulence.

Some food groups, such as fiber, can often lead to more frequent passing of gas, and so can gastrointestinal problems such as irritable bowel syndrome, or IBS. While too much can be an issue, too little is actually the bigger concern. A sudden inability to pass gas, especially alongside stomach pain or bloating, can signal a blockage or other serious gut problem that needs medical attention.

Researchers have not yet been able to clearly define what counts as excessive, too little or normal passing of gas. Without solid data on how often healthy people actually pass gas in daily life, it is difficult to know what is healthy and what is a potential digestive problem. Past studies usually looked at small groups of people or focused only on those with stomach problems.

In the study nearly 80% of participants fell within a range of two to seven times daily. The youngest group, ages 14 to 25, reported passing gas less often than all other age groups, while men averaged 5.2 times per day compared with 4.8 times for women. The number of recordings remained low during midday and began to rise after 6 p.m., when people are more likely to start eating their highest-calorie meals.

The researchers highlight that this study might be one of the first to describe real-time flatulence habits in a large, general population. Establishing what is normal for flatulence can not only provide a helpful starting point for discussions about symptoms at both ends of the spectrum, but also help monitor gut health and change social attitudes toward flatulence.

Emily Brindal et al, Regular Flatulence Patterns Among Community-Dwelling Individuals in Australia, JAMA Network Open (2026). DOI: 10.1001/jamanetworkopen.2026.15637

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Comment by Dr. Krishna Kumari Challa 10 hours ago

Why does the Y chromosome retain UTY?

The human Y chromosome has lost many of its ancestral genes over millions of years of evolution. Yet a small number of genes, including UTY, have been evolutionarily retained despite their weak expression and reduced enzymatic activity. Why these genes persist has remained a longstanding question in chromosome biology.

A study, published in the journal Development, is the first to precisely map endogenous UTY occupancy across the human genome and demonstrate that UTY remains functionally involved in transcriptional regulation during early human development.
UTY is retained on the Y chromosome because it continues to contribute to transcriptional regulation during early human development, co-occupying active cis-regulatory elements with its X homolog UTX and supporting pluripotency-associated transcription factor localization. Despite weaker expression and occupancy than UTX, UTY maintains residual, largely noncatalytic regulatory functions, suggesting it is in an evolutionary transition phase rather than being fully redundant or lost.

Tomohiko Akiyama et al, Functional redundancy between UTY and UTX in regulating the localization of transcription factors involved in pluripotency, Development (2026). DOI: 10.1242/dev.205328

Comment by Dr. Krishna Kumari Challa 11 hours ago

Scientists map more than 200 years of nature's progress
Comparisons of current mammal communities along the Lewis and Clark Trail with historical records reveal significant changes in species composition and ecosystem function, largely due to land use, development, and species loss over two centuries. Dominant species such as bison and wolves are now absent or greatly reduced, indicating altered ecological roles and community dynamics.

For scientists, the project's goal goes beyond documenting which species remain. By pairing modern data with Lewis and Clark's observations, they are examining how centuries of land use, development, and species loss have reshaped entire ecosystems.

https://showme.missouri.edu/2026/mizzou-helps-smithsonian-map-more-...

Comment by Dr. Krishna Kumari Challa 11 hours ago

Corals have a hormonal clock and it looks surprisingly like ours

A three-year study has cracked open the hidden biology behind coral reproduction, revealing hormone cycles that echo those of humans and other animals, and a new way to detect reef distress before it's too late.
Corals exhibit annual reproductive hormone cycles, with estrogen peaking months before spawning and progesterone surging after, paralleling patterns seen in other animals. Sunlight, rather than temperature, primarily regulates these hormone levels. These findings provide a baseline for detecting reproductive stress in corals, aiding early intervention in reef conservation.

Once a year, on cue, corals across a reef release their eggs and sperm into the sea simultaneously. Coral reproduction is one of nature's most spectacular events. For reefs increasingly threatened by warming, pollution and overfishing, getting that timing right is a matter of survival.
A team of researchers has uncovered evidence that corals may rely on hormone cycles like those used by many animals, including humans, to prepare for reproduction.
Their findings reveal a hidden biological rhythm that may help explain how corals coordinate reproduction and how scientists might detect reproductive stress before spawning failures become visible.
Scientists had previously suspected that estrogen-like hormones would peak just before corals spawned. Instead, the researchers found that estrogen levels reached their highest point months earlier, during the earliest stages of egg development, before steadily declining as eggs matured.

Meanwhile, progesterone remained relatively stable throughout the reproductive season but surged several months after spawning, suggesting it may help initiate the next reproductive cycle.

Equally surprising: Sunlight, not heat, emerged as the dominant driver of these hormone levels.
So there's a whole process beforehand, driven by these familiar reproductive hormones, which are remarkable to find in corals, animals so evolutionarily distant from us.
The team discovered another surprise inside individual coral colonies. Hormone levels were distributed fairly evenly throughout the colony, yet the central portions of corals were far more likely to contain developing eggs than the growing outer edges. The finding suggests that local conditions within a colony, such as age, energy reserves or developmental stage, may determine which polyps respond to reproductive signals.

Beyond advancing basic science, the findings could have practical implications for conservation.

Chen Azulay et al, Steroid hormones dynamics during coral reproduction: Multi-year patterns in Acropora eurystoma from the Red Sea, iScience (2026). DOI: 10.1016/j.isci.2026.116205

Comment by Dr. Krishna Kumari Challa 12 hours ago

Bacteria can learn and form memories without a brain

Researchers have shown that bacteria can learn from past experiences, store memories across generations and adapt their behaviour to changing environments, all without a brain or nervous system. The research could shape how scientists think about bacterial infections and antibiotic treatment.
E. coli bacteria can encode and transmit memories of past environmental conditions, enabling adaptive responses to fluctuating nutrient availability. These memory effects persist across generations via inherited molecular components, influencing behaviour even in descendants. The findings indicate bacterial responses depend on both current and historical environments, with implications for understanding infection dynamics and antibiotic resistance.
In a study published in PRX Life, researchers tracked individual E. coli cells as nutrient conditions shifted between rich and poor environments. Instead of responding the same way every time, the bacteria adjusted their growth based on patterns they had experienced before. Cells exposed to rapidly changing conditions were able to adapt better than cells raised in more stable environments.

The findings suggest bacteria do more than just react to their surroundings. They appear to encode memories of past environments and use those memories to guide future behaviour.

Josiah C. Kratz et al, Multi-Timescale Adaptation and Emergent Learning in Single Bacterial Cells, PRX Life (2026). DOI: 10.1103/5zbg-8vll

Comment by Dr. Krishna Kumari Challa yesterday

CAR-T enables kidney transplants

A single dose of engineered immune cells has helped three people with ‘highly sensitized’ immune systems to receive life-saving kidney transplants. People in this group are often ineligible for transplants because their bodies usually reject the donated organ. Researchers engineered the recipient’s own immune cells into chimeric antigen receptor (CAR) T cells that ultimately reduce the trouble-making antibodies that push their immune systems into overdrive. More than a year after receiving the cells, the three people are now living with new kidneys and without notable side effects.

https://www.nejm.org/doi/10.1056/NEJMoa2513428

https://www.nejm.org/doi/10.1056/NEJMc2517277

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