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Comment by Dr. Krishna Kumari Challa on Friday

Scientists solve 66 million-year-old mystery of how Earth's greenhouse age ended

A 66 million-year-old mystery behind how our planet transformed from a tropical greenhouse to the ice-capped world of today has been unraveled by scientists. Their new study has revealed that Earth's massive drop in temperature after the dinosaurs went extinct could have been caused by a large decrease in calcium levels in the ocean.

An international team of experts  discovered that concentrations of calcium in the sea dropped by more than half across the last 66 million years.

The study, published in Proceedings of the National Academy of Sciences, showed that the dramatic calcium shift may have sucked carbon dioxide—a major greenhouse gas—out of the atmosphere, driving global cooling.

Large changes in the composition of seawater chemistry may have been a key driver for climate change.

Their results show that dissolved calcium levels were twice as high at the start of the Cenozoic Era, shortly after dinosaurs roamed the planet, compared to today.

When these levels were high, the oceans worked differently, acting to store less carbon in seawater and releasing carbon dioxide into the air.

As those levels decreased, CO₂ was sucked out of the atmosphere, and Earth's temperature followed, dropping our climate by as much as 15 to 20 degrees Celsius.

They used fossilized remains of tiny sea creatures dug up from sediments at the seafloor to construct the most detailed record of ocean chemistry to date. The chemical composition of the fossils, called foraminifera, showed a close link between the amount of calcium in seawater and the level of carbon dioxide in the air.

Using computer-made models, the team showed that high levels of calcium change how much carbon is "fixed" by marine life, such as corals and plankton.

Part1

Comment by Dr. Krishna Kumari Challa on Friday

Scientists may have discovered a new extinct form of life

Prototaxites are something of a prehistoric mystery. They were the first giant organisms on land, towering over ancient landscapes at heights of up to 8 meters. They had smooth trunk-like pillars and no branches, leaves or flowers. And unlike trees, they had no true root system. Instead, they may have been anchored to the ground by a simple bulbous base.

Since their first fossils were discovered in the mid-19th century, scientists have argued over their place in the tree of life. Are they giant fungi, massive algae or some kind of plant? But new evidence has emerged that may help settle the matter.

According to a new study published in the journal Science Advances, Prototaxites belonged to a previously unknown, now-extinct branch of life.

The researchers studied a specimen of Prototaxites taiti recovered from the Rhynie Chert in northeastern Scotland. This paleontological site is well-known for its exceptionally well-preserved plant, fungal and animal material.

The team used lasers and 3D imaging to look inside the fossils and compared their chemical compositions with those of other fossils found in the same rock. They discovered two significant differences.

While fungi have simple networks of long, tubular structures called hyphae, the Prototaxite specimen had a much more complex internal structure. It comprised three different types of tubes and dense hubs where they branch and connect.

To study its chemical fingerprint (the chemical signature organisms leave behind based on the cells they are made of), the team used artificial intelligence. The protein chitin is often detected in fossilized fungi and insects, but it was completely missing from the Prototaxites sample. They also used artificial intelligence to see if its chemistry matched that of any living organism. It didn't.

The researchers ruled out the giant fossils being fungi or plants, and instead, they conclude that Prototaxites were members of an extinct lineage of eukaryotes (complex-celled organisms).

The findings may have finally solved the long-standing mystery about the true nature of Prototaxites. However, further analysis and fossil discoveries may well be needed before the results are considered conclusive.

Corentin Loron et al, Prototaxites fossils are structurally and chemically distinct from extinct and extant Fungi, Science Advances (2026). DOI: 10.1126/sciadv.aec6277. www.science.org/doi/10.1126/sciadv.aec6277

Comment by Dr. Krishna Kumari Challa on Thursday

What should you do with unused or expired prescription medications?

Unused or expired prescription medications should be disposed of promptly to prevent accidental ingestion, especially by children. Preferred disposal methods include take-back programs at pharmacies, police stations, or DEA events. If these are unavailable, mix medications with unpalatable substances before discarding in the trash. Some drugs, mainly opioids, may be flushed per FDA guidance. Sharps require separate disposal.

If you have unused or expired medication, the best thing is to dispose of it. Many people hang on to them, and this just creates opportunity for things to go wrong.

https://medicalxpress.com/news/2026-01-unused-expired-prescription-...

Comment by Dr. Krishna Kumari Challa on Thursday

Small number of 'highly plastic' cancer cells drive disease progression and treatment resistance
A small subset of highly plastic cancer cells, capable of shifting identity and behavior, drives tumor progression and treatment resistance. These cells, which increase in prevalence as tumors advance, exploit injury-repair programs and can survive therapies by adapting rapidly. Targeting them, for example via uPAR-directed CAR T cells, significantly impairs tumor growth and may enhance treatment efficacy.

In healthy tissues, stem cells make new cells to replace those that are lost or damaged through normal wear and tear.

Most organs maintain themselves with resident stem cells tailored to that type of tissue—alveoli or bronchial cells in the lung, skin cells, intestinal cells, and so on.

But when an injury occurs, special injury repair programs get triggered that put stem cells in an even more flexible state—"like a super stem cell." This allows the cell to expand its capabilities and produce a much wider variety of new cells.

The problem is when cancer cells borrow these programs that are normally only available to stem cells.

Indeed, it's these highly flexible—highly plastic—cell states related to injury repair that cancer hijacks. Highly plastic cells become more abundant as these tumors grow,  researchers found. 

These highly plastic cells aren't necessary to initiate a tumor. But they're critical to cancer's progression, the team found—including its ability to give rise to fast-growing cells, to evolve resistance to treatment, and to potentially help the cancer spread to other parts of the body.

If we kill off these plastic cells very early in the initiation of a tumor, you can basically prevent mutated cells from ever becoming cancers, say teh researchers.

Tuomas Tammela, Critical role for a high-plasticity cell state in lung cancer, Nature (2026). DOI: 10.1038/s41586-025-09985-x. www.nature.com/articles/s41586-025-09985-x

Comment by Dr. Krishna Kumari Challa on Thursday

Strikingly, these same genetic variants that influence the risk of pregnancy loss are also associated with recombination, the genetic shuffling process that generates diversity when eggs and sperm are made, they found.

Female meiosis, or the cell division necessary for reproduction, begins during fetal development, when chromosomes pair and recombine. The process then pauses for decades, until ovulation and fertilization. During this long pause, problems in the machinery that keeps chromosomes together can cause them to separate too soon, leading to an abnormal chromosome count when meiosis resumes.
The results demonstrate that inherited differences in these meiotic processes contribute to natural variation in risk of aneuploidy and pregnancy loss between individuals.

Rajiv McCoy, Common variation in meiosis genes shapes human recombination and aneuploidy, Nature (2026). DOI: 10.1038/s41586-025-09964-2. www.nature.com/articles/s41586-025-09964-2

Part 2

Comment by Dr. Krishna Kumari Challa on Thursday

Maternal genetic factors may reveal why pregnancy loss is so common

Pregnancy loss in humans is common, with about 15% of recognized pregnancies resulting in miscarriage and many more conceptions being lost at early stages without people realizing it.
Analysis of genetic data from nearly 140,000 IVF embryos demonstrates that common maternal genetic variants, particularly in genes involved in chromosome cohesion and recombination, contribute to individual differences in the risk of pregnancy loss due to chromosomal errors. These findings clarify molecular pathways underlying aneuploidy and suggest potential targets for future therapies.

By studying genetic data from nearly 140,000 IVF embryos, scientists have with unprecedented detail revealed why fewer than half of human conceptions survive to birth. The research uncovered the strongest evidence yet for how common genetic differences leave some individuals more vulnerable to pregnancy loss.

The vast dataset allowed the  team to demonstrate robust connections between specific variations in a mother's DNA and their risk of miscarriage.

The findings shed new light on human reproduction and suggest pathways for developing treatments to lower the risk of pregnancy loss.

Most chromosome errors originate in the egg and increase in frequency with a mother's age. More mysterious is how factors beyond age, such as genetic differences, may predispose a person to produce eggs with abnormal numbers of chromosomes in the first place.

Figuring that out requires analyzing genetic data from large numbers of embryos before pregnancy loss, as well as their biological parents.

The strongest associations appear in genes that govern how chromosomes pair, recombine, and are held together during egg formation, including a gene (SMC1B) that encodes part of the ring-shaped structure that encircles and binds chromosomes, the team found. These rings are essential for accurate chromosome segregation and tend to break down as women age.

Part 1

Comment by Dr. Krishna Kumari Challa on Thursday

What the brain's shape and complexity say about a newborn's development

The neonatal period, which is defined as the first 28 days after birth, is known to be a crucial stage in the development of the human brain. During this stage, the brain is known to grow significantly in size, with billions of new connections forming between neurons and supporting basic physiological functions.

Researchers recently carried out a study aimed at further exploring how the human brain's overall shape and size as well as the dimensions of distinct regions are linked to a newborn's development and maturity. Their findings, published in Nature Neuroscience, suggest that the brain's shape is a key marker of development during the neonatal period.

They analyzed publicly available magnetic resonance imaging (MRI) data collected from almost 800 human newborns as part of the developing Human Connectome Project (dHCP). Employing a mathematical method called fractal analysis, they tried to delineate the shape of the newborns' brains.

This approach yields a geometric measure called fractal dimensionality (FD) that describes the shape of a brain region in terms of its structural complexity.

Brain shape predicted the infants' ages significantly better than brain size, say teh researchers. Moreover, brain shape captured signatures of premature birth that were not detected with brain size.

They found that the brains of infants who were related to each other, such as twins, were more similar in shape than those of unrelated infants. The shape of the brains of identical twins, who share almost 100% of genes, was found to be more similar than those of fraternal twins, who share approximately 50% of genes.

Based on this relationship, the researchers were able to predict which babies are twin siblings from their brain shapes with high accuracy (~77% overall, ~97% in identical twins), again outperforming all other studied brain measures.

These results suggest that the early-life formation of brain shape represents a fundamental maturational process in human brain development.

Stephan Krohn et al, Fractal analysis of brain shape formation predicts age and genetic similarity in human newborns, Nature Neuroscience (2025). DOI: 10.1038/s41593-025-02107-w

Comment by Dr. Krishna Kumari Challa on Wednesday

Cancer patients warned popular supplement may interfere with treatment

Biotin supplements, commonly used by cancer patients to address hair loss, lack strong evidence for promoting hair or nail regrowth and can interfere with lab tests, potentially leading to inaccurate results and delayed or altered treatment. Biotin may cause false readings in tests for prostate, thyroid, ovarian, and breast cancers. Minoxidil is a safer, effective alternative for hair loss.

Layna Mager et al, Biotin Supplements for Hair and Nail Regrowth: A Caution for Oncologists, JCO Oncology Practice (2025). DOI: 10.1200/op-25-00693

Cancer patients warned popular supplement may interfere with treatment

Comment by Dr. Krishna Kumari Challa on Wednesday

Certain antibiotics may may boost immune system
Fluoroquinolone antibiotics can directly alter macrophage metabolism by stressing their mitochondria, leading to increased production of nitric oxide and enhanced bacterial clearance. This effect is specific to certain younger macrophage subsets in the lung and gut. While these antibiotics may boost immune cell function, they also carry risks such as microbiome disruption and potential tissue damage from excessive inflammation.

Alexander W Hardgrave et al, Fluoroquinolones directly drive mitochondrial hyperpolarization and modulate iNOS expression in monocyte-derived macrophage populations, Discovery Immunology (2025). DOI: 10.1093/discim/kyaf018

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Comment by Dr. Krishna Kumari Challa on Wednesday

Chronic kidney disease poisons patients' hearts, scientists discover

Scientists have discovered an answer to the longstanding mystery of why more than half of patients with chronic kidney disease ultimately die of cardiovascular problems: Their kidneys produce a substance that poisons the heart.

Chronic kidney disease leads to the production of circulating extracellular vesicles in the kidneys, which carry toxic miRNA that harm the heart. Blocking these vesicles in animal models improved heart function. This mechanism may enable earlier identification and targeted treatment of heart failure risk in CKD patients.

The researchers say the discovery could let doctors identify people at risk and develop new treatments to help prevent and treat heart failure for these patients.

Xisheng Li et al, Circulating Extracellular Vesicles in the Pathogenesis of Heart Failure in Patients With Chronic Kidney Disease, Circulation (2026). DOI: 10.1161/circulationaha.125.075579

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