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Comment by Dr. Krishna Kumari Challa on Tuesday

Scratching that bug bite might feel good at first but science explains why it's a bad idea
Scratching itch-inducing skin lesions amplifies inflammation by mechanically triggering pain fibers that release substance P, which activates mast cells via a non-allergen pathway, increasing swelling and itch. Mouse “cone” experiments show preventing scratching markedly reduces inflammatory cells and edema. Although scratching can modestly reduce skin bacteria, the net effect is detrimental, and topical anti-itch therapies are recommended to break the itch-scratch cycle.

A lot of things can cause itchiness, sometimes serious diseases. Whatever the cause, doctors have long warned that scratching too much can damage the skin. Now researchers better understand why even a mildly annoying itch could put you on an itch-and-scratch cycle if you give in.
They also gained insight into why a good scratch at least at first brings a sigh of relief. After all, not just people and other mammals scratch, even fish do. The commonality suggests there must be some evolutionary reason and the mouse experiment hints at a little germ protection—but still not a reason to scratch.

Evidence matches people's everyday experiences that scratching really can make things worse.

Ignore a mosquito bite and the itch is "gone in five or 10 minutes for most people. But if you start scratching it, it's your friend for a week, getting itchier and more inflamed.
To understand what was happening in the skin, researchers took a deeper look at mast cells, among the immune system's first responders. When called into action, they release compounds that can help fight germs or toxins—or, through a compound called histamine, trigger itchy allergic reactions.

Scientists have long known that allergens can activate mast cells. But other signals can summon mast cells, too, including pain. And when we scratch, we tend to scratch until it starts to hurt.
Pain-sensing nerve cells release a chemical messenger called substance P. In findings published last year, the same team reported that substance P can activate mast cells through a different molecular pathway than allergens do—a double whammy that explains why scratching further inflames itchy rashes or bites.
If we experience pain like touching a hot stove, we'll learn not to do that again. Yet relief from a good scratch, in evolutionary terms, is positive feedback. Why?

One long-held theory is that it may help creatures slough off parasites like fleas or mites.

"Ultimately, scratching is deleterious," the researchers stressed. "You should avoid scratching, although it's "easier said than done."
Part 1

Comment by Dr. Krishna Kumari Challa on Tuesday

Scientists uncover how ovarian cancer resists chemotherapy—and how to reverse it
Ovarian cancer cells acquire cisplatin and carboplatin resistance by stabilizing microtubules via elevated TPPP3, altering the tubulin “code” beyond DNA repair mechanisms. High TPPP3 correlates with poorer survival, while TPPP3 loss restores cisplatin sensitivity in models, suggesting TPPP3 as a therapeutic target and potential biomarker for platinum resistance and treatment optimization.

Sachi Horibata et al, Cisplatin resistance in an ovarian cancer model is mediated by microtubule dynamics regulator TPPP3 in synergy with tubulin code rewiring, Cell Reports (2026). DOI: 10.1016/j.celrep.2026.117414

Comment by Dr. Krishna Kumari Challa on Tuesday

Childbirth is not uniquely difficult to humans

The tight fit of a baby's head through a mother's birth canal, which causes great difficulty in childbirth, is not unique to humans, as previously understood. Instead, some small-bodied primate babies have heads almost twice as large as their mothers' pelvic space, a new study led by UCL researchers has found.

Birth canal–neonate head mismatch occurs widely among small-bodied primates, not only humans, challenging the notion of a uniquely human obstetrical dilemma. Expanded 3D comparative analysis across 29 species shows especially tight fits in American monkeys, with some neonate heads nearly twice maternal pelvic space. Several taxa exhibit pelvic adaptations, such as delayed or absent pelvic bone fusion, that facilitate parturition.

The findings, published in Nature Ecology & Evolution, challenge the theory of an exclusively human "obstetrical dilemma"—the idea that our large heads and narrow pelvises, adapted for upright walking, have made childbirth uniquely difficult for our species.
Researchers have revisited the evidence and found that although constricted birth is not experienced by other apes, it is common among many small-bodied primates, particularly American monkeys like bushbabies and squirrel monkeys. For example, the heads of newborn squirrel monkeys can be almost twice the size of the mother's pelvic space.
Much of the data that informed earlier studies was flawed. It had been collected in a human-centric way that failed to consider the anatomy of other species.
In the past, the measurement for the newborns' heads was from the forehead to the back of the skull. This assumed that all babies are born crown-first, as most humans are. But species like the gelada monkey, with their pronounced snouts, are often birthed face-first.
Using advanced 3D modeling techniques and greatly expanding the number of species studied—from eight to 29—the research team found that tight fits at birth were especially common among proportionally smaller species.
The researchers found that some of the small-bodied primates that experience a constrained fit during childbirth have developed clever adaptations to make the process less difficult. The pelvic bones of female rhesus macaques fuse together later than in males, during their reproductive years, and in bushbabies they never fuse, allowing the pelvis to expand during birth to accommodate the neonatal head.

Nicole Torres-Tamayo, Comparative primate analysis shows that humans are not unique in having a tight cephalopelvic fit at birth, Nature Ecology & Evolution (2026). DOI: 10.1038/s41559-026-03102-5. www.nature.com/articles/s41559-026-03102-5

Comment by Dr. Krishna Kumari Challa on Tuesday

Decline in plankton across Northeast Atlantic sends stark warning for ocean health
Long-term analyses of 23 data sets across the Northeast Atlantic show widespread declines and community changes in phytoplankton and zooplankton, with no pelagic region achieving Good Environmental Status. Shelf habitats exhibit the poorest condition. Changes correlate with warming, nutrient shifts, acidification, and altered mixing, indicating impaired food webs and carbon cycling and underscoring the need for emission cuts, nutrient control, and sustained plankton monitoring.

Abigail McQuatters-Gollop et al, Integrating plankton indicators to assess the state of pelagic habitats in the Northeast Atlantic, Ecological Indicators (2026). DOI: 10.1016/j.ecolind.2026.115005

Comment by Dr. Krishna Kumari Challa on Tuesday

Coastal and estuarine carbon removal technique may backfire when pushed too far

The ocean already absorbs around a quarter of human-generated carbon dioxide emissions, making it one of Earth's most important natural carbon sinks. Ocean alkalinity enhancement seeks to increase this capacity by raising the alkalinity of seawater, allowing it to take up additional carbon dioxide from the atmosphere.

Scientists investigating a proposed way to remove carbon dioxide from the atmosphere using seawater have found that adding too much alkalinity to neutralize acids can trigger chemical reactions that undermine the process.
The study, published in Frontiers in Marine Science, examined a form of marine carbon dioxide removal known as ocean alkalinity enhancement. The approach aims to increase the ocean's capacity to absorb carbon dioxide by adding alkaline substances that shift seawater chemistry and encourage more carbon dioxide to move from the atmosphere into the ocean.

Using dissolved calcium carbonate (the main mineral found in limestone and seashells), the researchers found that there are clear limits to how much alkalinity can be added before the chemistry becomes unstable. At high doses, calcium carbonate rapidly forms solid mineral particles, effectively undoing some of the intended carbon storage benefits. The findings help define practical boundaries for the technique and highlight the importance of tailoring it to local conditions.
However, there is a catch. If conditions become too favorable for minerals to form, dissolved calcium carbonate can begin to crystallize and precipitate back out of the water. This removes some of the added alkalinity before it has had time to draw down atmospheric carbon dioxide and, in extreme cases, could even release carbon dioxide back into the atmosphere.

To investigate where these limits lie, the researchers tested three different alkalinity additions under a range of temperatures and carbon dioxide conditions. They also explored how mixing treated seawater with natural river water affected stability.

The lowest dose remained stable for more than a month, while the highest dose consistently caused calcium carbonate precipitation within a day. An intermediate level showed mixed behavior, with the timing of precipitation strongly influenced by temperature and the precise chemical conditions of the water.

The results revealed a threshold effect: Below certain levels, the enhanced seawater remained chemically stable, but above them the risk of precipitation increased sharply. Although the highest additions led to rapid mineral formation, the researchers did not observe a worst-case "runaway" scenario in which more alkalinity was lost than had originally been added.

The team also found that mixing treated seawater with natural estuarine water improved stability

Amanda B. Melendez-Perez et al, Stability assessment of calcium carbonate dissolution as a marine carbon dioxide removal mechanism, Frontiers in Marine Science (2026). DOI: 10.3389/fmars.2026.1796693

Comment by Dr. Krishna Kumari Challa on Tuesday

Giant exoplanet may hold a magnetic grip on its host star

Within their planetary systems, stars are continuously shaping their orbiting planets through gravity, radiation and magnetic forces. So far, this relationship has appeared to be a one-way street.
But through new research published in Science, an international research team has found compelling evidence that the dynamic can run in reverse: A giant exoplanet orbiting very close to its star appears to be leaving a measurable magnetic imprint on the star itself.
The ways in which stars influence their planets are varied and powerful. Gravitationally, a star can distort a planet's orbit over time, stretching it or locking its rotation into step with its orbit. Radiatively, the intense light and high-energy particles streaming from a star can erode a planet's atmosphere, gradually stripping away lighter gases.

Magnetically, the star's field pervades the surrounding space, interacting with any magnetic field the planet itself possesses. In most cases, the star so thoroughly dominates these interactions that any influence the planet might exert in return is negligible.

For their study, the team focused on a red dwarf star called GJ 436, located about 30 light-years from Earth and roughly half the mass of our sun. It is orbited by a single known planet: a world around the size of Neptune and four times the mass of Earth. The exoplanet also completes a full orbit every 2.6 days, placing it extraordinarily close to its host star.

The researchers analyzed 18 years of high-resolution spectroscopic observations of the star, tracking specific emission signatures from hydrogen and calcium in its outer atmospheric layer. Since these signatures are sensitive to the star's magnetic environment, they are an especially useful indicator of activity.
Remarkably, the team found periodic fluctuations in these signals that matched the planet's orbital period—suggesting the planet was somehow triggering a rhythmic response in the star. This signal wasn't always present, however. During periods of high stellar activity, it was drowned out, and during very quiet periods, there was too little background activity for the planet's influence to enhance. But at intermediate activity levels, a clear periodic pattern emerged.

To explain this unusual pattern, the team modeled a physical connection between the magnetic field lines of the planet and star, which funnel energy into the star's outer atmosphere. Accounting for the star's rotation and the planet's tilted, eccentric orbit, this model was able to reproduce the observations and placed the planet's magnetic field strength as comparable to Jupiter's.
The findings present the possibility of an entirely new type of relationship between exoplanets and their host stars.

D. Revilla et al, Constraining an exoplanet's magnetic field using star-planet interactions, Science (2026). DOI: 10.1126/science.adv3075

Comment by Dr. Krishna Kumari Challa on Tuesday

Large MRI analysis uncovers brain-region thinning tied to depression

Major depressive disorder (MDD) is a psychiatric condition characterized by persistent feelings of sadness, a loss of interest in everyday activities, altered sleeping and/or eating patterns, low energy, and difficulty concentrating on tasks. While it is one of the most widespread mental health disorders worldwide, its unique neural and brain-related signatures have not yet been fully uncovered.

Recent studies have been trying to uncover differences in the structure of the brain associated with specific mental health disorders. This has mainly been done by analyzing brain scans collected from psychiatric patients using magnetic resonance imaging (MRI), a medical imaging technique that collects detailed images of specific organs using strong magnetic fields and radio waves.

Researchers recently performed a large-scale analysis of MRI scans collected from individuals diagnosed with depression and from people with no known mental health disorders. The results of their analysis, published in Nature Mental Health, unveiled differences in the structure of specific brain regions associated with depression, which appear to vary based on age, treatment stage, and medication use.

The researchers analyzed MRI brain scans collected from 5,736 patients with MDD and 6,538 individuals with no known psychiatric conditions. These scans were collected by 64 independent research groups worldwide as part of two international research projects.

The analyses show significantly lower cortical thickness in patients with MDD in multiple brain regions, including the inferior parietal, lateral occipital, superior parietal, medial and lateral orbitofrontal, anterior and posterior cingulate, and precentral gyri, with cortical surface area showing no significant differences.

The team found that people with depression exhibited thinner cortical layers across various brain regions, but no significant differences in these regions' surface area. These observed differences appeared to be more pronounced in adult patients who were having an acute depressive episode. In contrast, adolescents with depression did not present any significant differences in brain structure compared with adolescents with no mental health disorders.

The researchers also observed slightly more prominent cortical thinning in the brains of patients who were taking antidepressant medications, such as selective serotonin reuptake inhibitors (SSRIs) and serotonin and norepinephrine reuptake inhibitors (SNRIs). Nonetheless, the effects of antidepressant use on people's brain structure appeared to be subtle and modest in size.

Chao-Gan Yan et al, Vertex-wise cortical abnormalities in major depressive disorder from 64 cohorts from the DIRECT and ENIGMA MDD consortia, Nature Mental Health (2026). DOI: 10.1038/s44220-026-00667-9.

Comment by Dr. Krishna Kumari Challa on June 27, 2026 at 12:02pm

Ovaries start second job after menopause

After the ovaries ramp down their reproductive role, releasing eggs and sex hormones, they might become more important to the immune system. Evidence from people and mice suggest that genes and proteins associated with immune activity are more active and prevalent in postreproductive ovaries — though it’s unclear whether it's a beneficial change.

Researchers found signs of reproductive function, including markers associated with egg and steroid production, diminished with age among the mice they tested. But the analyses of post-reproductive ovaries also revealed various kinds of immune cells at higher levels than what’s typical in younger mice. Older ovaries also showed greater activity of genes that encode different pro-inflammatory compounds, immune molecules that could be secreted into the bloodstream and travel to other parts of the body.

Whether older ovaries actually carry out any immune signalling or simply become an unintended reservoir for immune cells remains unclear. The new mouse study is interesting because it provides a potential idea as to what the post-reproductive ovary might be doing. The ovary might become a site where immune cells … come and get changed in some way that would potentially have systemic effects.

The finding could help explain why women tend to be less healthy than men as they age, even though they live longer.

The postreproductive ovary could secrete molecules that predispose people to chronic inflammation in their menopausal years. 

https://academic.oup.com/molehr/advance-article/doi/10.1093/molehr/...

Comment by Dr. Krishna Kumari Challa on June 27, 2026 at 11:16am

Concussion symptom history linked to increased odds of tinnitus

Greater concussion symptom history is associated with increased odds of tinnitus, and associations with cognition, depression, and anxiety are larger among those with tinnitus, according to a study published online June 19 inSports Medicine Open.

In former professional American football players, greater self-reported concussion symptom history was associated with higher odds of tinnitus (odds ratio 2.90 for highest vs lowest quintile). Tinnitus did not mediate associations between concussion history and neurobehavioral outcomes, but individuals with tinnitus showed stronger associations with perceived cognitive problems, depression, and anxiety.

Niki A. Konstantinides et al, Associations Between Football-Related Exposures, Head Injury, Tinnitus, and Neuropsychological Health Outcomes Among Professional American-Style Football Players, Sports Medicine—Open (2026). DOI: 10.1186/s40798-026-01053-6

Comment by Dr. Krishna Kumari Challa on June 27, 2026 at 10:59am

How we see colour revealed at the molecular level

To understand how we detect light and perceive colours, we need to know the exact structure of light-sensitive molecules in our eyes.

A global team now has cracked a decades-old mystery, revealing the atomic structures of the molecules in our eyes that allow us to see colours. 

Our perception of colour is mainly determined by the relative excitation of red-, green- and blue-sensitive cone photoreceptor cells found inside our retinas that contain these molecules.

There are three versions of the molecules, called cone opsins, with each converting red, green or blue light into chemical signals.

Revealing the atomic structures for each of the molecules in their light-activated state shows how they work inside cone cells to trigger signals that are ultimately sent to the brain. ?The results reveal fundamental differences between the cone opsins when they enter their active state after being hit with light.

Like how a high shutter speed lets a camera capture sharper images, having color-detecting molecules in our eyes that turn on and off quickly is thought to allow us to see sharp detail and color in motion accurately in daylight.

All three cone opsins contain the same light-sensitive vitamin A-derived molecule, with red, green and blue opsins binding to this molecule, called retinaldehyde, differently.

The red and green opsins appear to use very different placement of chemical electronic charges around the retinaldehyde. This difference explains how they shut off faster than the blue opsin, and much faster than the rod pigment.

In the long term, this development could help scientists discover better treatments for some vision disorders, such as cone dystrophies and altered colour vision.

Qi Peng et al, Cryo–electron microscopy structures of human cone visual pigments, Science (2026). DOI: 10.1126/science.adz8141

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