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Comment by Dr. Krishna Kumari Challa on April 7, 2025 at 8:34am

Scientists discover how nanoparticles of toxic metal used in MRI scans infiltrate human tissue

 Researchers studying the health risks posed by gadolinium, a toxic rare earth metal used in MRI scans, have found that oxalic acid, a molecule found in many foods, can generate nanoparticles of the metal in human tissues.

In a new paper published in the journal Magnetic Resonance Imaging, a research team  sought to explain the formation of the nanoparticles, which have been associated with serious health problems in the kidneys and other organs.

The worst disease caused by MRI contrast agents is nephrogenic systemic fibrosis. People have succumbed after just a single dose. The condition can cause a thickening and hardening of the skin, heart and lungs and cause painful contracture of the joints.

Gadolinium-based contrast agents are injected prior to MRI scans to help create sharper images.

The metal is usually tightly bound to other molecules and is excreted from the body, and most people experience no adverse effects. However, previous research has shown that even in those with no symptoms, gadolinium particles have been found in the kidney and the brain and can be detected in the blood and urine years after exposure.

Scientists are left with intertwined puzzles: Why do some people get sick, when most don't, and how do gadolinium particles become pried loose from the other molecules in the contrast agent?

Almost 50% of the patients had been exposed only a single time, which means that there's something that is amplifying the disease signal.

In their study, the research team focused on oxalic acid, which is found in many plant-based foods, including spinach, rhubarb, most nuts and berries and chocolate, because it binds with metal ions. The process helps lead to the formation of kidney stones, which result when oxalate binds with calcium. Meanwhile, oxalic acid also forms in the body when people eat foods or supplements containing vitamin C.

In test tube experiments the researchers found that oxalic acid caused minute amounts of gadolinium to precipitate out of the contrast agent and form nanoparticles, which then infiltrated the cells of various organs.

Some people might form these things, while others do not, and it may be their metabolic milieu. It might be if they were in a high oxalic state or a state where molecules are more prone to linking to the gadolinium, leading to the formation of the nanoparticles. That might be why some individuals have such awful symptoms and this massive disease response, whereas other people are fine.

The finding points to a possible way to mitigate some of the risks associated with MRI scan.

The scientists are getting closer to some recommendations for helping these individuals who are susceptible.

Ian M. Henderson et al, Precipitation of gadolinium from magnetic resonance imaging contrast agents may be the Brass tacks of toxicity, Magnetic Resonance Imaging (2025). DOI: 10.1016/j.mri.2025.110383

Comment by Dr. Krishna Kumari Challa on April 6, 2025 at 11:18am

Researchers identified curious DNA "dots" within infected cells under a light microscope. Professor Elizabeth Villa's laboratory then used high-end imaging technologies to discover that these dots were tiny vesicles containing viral DNA and molecular machineries outside these vesicles.
They found that these vesicles were actually metabolically active, confirming the purpose of the molecular machines hanging outside the vesicles.
Not only did the researchers show that these vesicles are making RNA, but also they are getting ready to establish infection by synthesizing genes important for nucleus formation.

Emily G. Armbruster et al, Sequential membrane- and protein-bound organelles compartmentalize genomes during phage infection, Cell Host & Microbe (2025). DOI: 10.1016/j.chom.2025.03.005

Part 2

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

Jumbo phages infect cells with a protective cloaking mechanism, researchers discover

In a growing global trend, bacteria are evolving new ways to maneuver around medical treatments for a variety of infections. The rising antibiotic resistance crisis poses a significant public health threat in hospitals and other settings, with infections resulting in millions of deaths in recent years.

Scientists are now looking to bacteriophages—viruses that infect bacteria—and their potential to treat drug-resistant infections. They have begun to look deeper into an intriguing class of large bacteriophage known as "jumbo phages" that exhibit extraordinary features as possible new agents for bacterial infection treatments.

A study by  researchers has shed new light on the unusual ways that phages have evolved to infect bacteria. Over millions of years, viruses and bacteria have engaged in a back-and-forth arms race. Viruses develop new ways to infect bacteria, while bacteria counter by evolving a resistance mechanism.

In order to fully realize the potential of jumbo phages and their promise as new therapeutics, researchers must decipher the mechanisms they employ to infect bacteria and evade the host's defenses.

A new study published in the journal Cell Host & Microbe describes the first-of-its-kind discovery of a type of membrane-bound sac, or vesicle, used by jumbo phages of the Chimalliviridae family.

The researchers  found that immediately after jumbo phages infect a bacterial cell, they form a structure that shields and hides valuable DNA material. Phages use this genetic material to develop a nucleus inside their bacterial hosts.

The newly discovered compartment, which they named the EPI, or early phage infection vesicle, serves as a type of cloaking device that prevents triggering the bacteria's immune system.

When phages infect a bacterial cell, the EPI vesicle protects the genome of the virus during early stages of infection when it's very vulnerable. Bacteria and viruses are often dismissed as simple organisms but they're actually capable of very sophisticated intracellular warfare and this study is a new example of that.

Because most phages simply inject their DNA directly into the host, effectively announcing their arrival within the cell, the results of Chimalliviridae phage's stealth approach came as a revelation to researchers.  The bacteria don't realize that there's a virus in there, producing things that will eventually take over.

Part 1

Comment by Dr. Krishna Kumari Challa on April 6, 2025 at 11:06am

Antibiotic resistance among key bacterial species plateaus over time, study shows

Antibiotic resistance tends to stabilize over time, according to a study published in the open-access journal PLOS Pathogens.

In this study, researchers analyzed drug resistance in more than 3 million bacterial samples collected across 30 countries in Europe from 1998 to 2019. Samples encompassed eight bacteria species important to public health, including Streptococcus pneumoniae, Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae.

They found that while antibiotic resistance initially rises in response to antibiotic use, it does not rise indefinitely. Instead, resistance rates reached an equilibrium over the 20-year period in most species.

Antibiotic use contributed to how quickly resistance levels stabilized as well as variability in resistance rates across different countries. But the association between changes in drug resistance and antibiotic use was weak, suggesting that additional, yet unknown, factors are at play.

The study highlights that a continued increase in antibiotic resistance is not inevitable and provides new insights to help researchers monitor drug resistance.

When researchers looked into the dynamics of antibiotic resistance in many important bacterial pathogens all over Europe and in the last few decades, they often found that resistance frequency initially increases and then stabilizes to an intermediate level. The consumption of the antibiotic in the country explained both the speed of initial increase and the level of stabilization.

PLOS Pathogens (2025). DOI: 10.1371/journal.ppat.1012945

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Comment by Dr. Krishna Kumari Challa on April 6, 2025 at 10:55am

This approach, however, requires making predictions about which lineages were aerobic in the deep past. The team used probabilistic methods to infer which genes ancient genomes contained, and then machine-learning to predict whether they used oxygen.

To best utilize the fossil record, they leveraged fossils of eukaryotes, whose mitochondria evolved from Alphaproteobacteria, and chloroplasts evolved from cyanobacteria to better estimate how and when aerobic bacteria evolved.

Their results indicate that at least three lineages had aerobic lifestyles before the GOE—the earliest nearly 900 million years before—suggesting that a capacity for using oxygen evolved well before its widespread accumulation in the atmosphere.

Intriguingly, these findings point to the possibility that aerobic metabolism may have occurred long before the evolution of oxygenic photosynthesis.
Evidence suggests that the earliest aerobic transition occurred in an ancestor of photosynthetic cyanobacteria, indicating that the ability to utilize trace amounts of oxygen may have allowed the development of genes central to oxygenic photosynthesis.

The study estimates that the last common ancestor of all modern bacteria lived sometime between 4.4 and 3.9 billion years ago, in the Hadean or earliest Archean era. The ancestors of major bacterial phyla are placed in the Archean and Proterozoic eras (2.5–1.8 billion years ago), while many families date back to 0.6–0.75 billion years ago, overlapping with the era when land plants and animal phyla originated.

Notably, once atmospheric oxygen levels rose during the GOE, aerobic lineages diversified more rapidly than their anaerobic counterparts, indicating that oxygen availability played a substantial role in shaping bacterial evolution.
This combined approach of using genomic data, fossils, and Earth's geochemical history brings new clarity to evolutionary timelines, especially for microbial groups that don't have a fossil record.

A geological timescale for bacterial evolution and oxygen adaption, Science (2025). DOI: 10.1126/science.ADP1853

Part 2

Comment by Dr. Krishna Kumari Challa on April 6, 2025 at 10:53am

Molecular clock analysis shows bacteria used oxygen long before widespread photosynthesis

Microbial organisms dominate life on Earth, but tracing their early history and evolution is difficult because they rarely fossilize. Determining when exactly a particular group of microbes first appeared is especially hard. However, ancient sediments and rocks hold chemical clues of available nutrients that could support the growth of bacteria.

A key turning point was when oxygen accumulated in the atmosphere around 2.3 billion years ago. Scientists have used this oxygen surge and how microbes adapted to it to map out bacterial evolution.

In a study published in Science, researchers have constructed a detailed timeline for bacterial evolution and oxygen adaptation.

Their findings suggest some bacteria could use trace oxygen long before evolving the ability to produce it through photosynthesis.

The researchers focused on how microorganisms responded to the Great Oxygenation Event (GOE) some 2.3 billion years ago. This event, triggered in large part by the development of oxygenic (oxygen-generating) photosynthesis in cyanobacteria and carbon deposition, fundamentally changed Earth's atmosphere from one mostly devoid of oxygen to one where oxygen became relatively abundant, as it is today.

Until now, establishing accurate timescales for how bacteria evolved before, during, and after this pivotal transition has been difficult due to incomplete fossil evidence and the challenge of determining the maximum possible ages for microbial groups—given that the only reliable maximum limit for the vast majority of lineages is the moon-forming impact 4.5 billion years ago, which likely sterilized the planet.

The researchers addressed these gaps by concurrently analyzing geological and genomic records. Their key innovation was to use the GOE itself as a time boundary, assuming that most aerobic (oxygen-using) branches of bacteria are unlikely to be older than this event—unless fossil or genetic signals strongly suggest an earlier origin. Using Bayesian statistics, they created a model that can override this assumption when data supports it.

part1

Comment by Dr. Krishna Kumari Challa on April 6, 2025 at 9:22am

 The Dangers of Going to Space

Comment by Dr. Krishna Kumari Challa on April 6, 2025 at 8:43am

Female hormones can stimulate immune cells to make opioids that naturally suppress pain

Scientists have discovered a new mechanism that acts via an immune cell and points toward a different way of treating chronic pain. Female hormones can suppress pain by making immune cells near the spinal cord produce opioids, a new study by researchers  has found. This stops pain signals before they get to the brain.

The discovery could help with developing new treatments for chronic pain. It may also explain why some painkillers work better for women than men and why postmenopausal women experience more pain.

The work reveals an entirely new role for T-regulatory immune cells (T-regs), which are known for their ability to reduce inflammation.

The researchers looked at T-regs in the protective layers that encase the brain and spinal cord in mice. Until now, scientists thought these tissues, called the meninges, only served to protect the central nervous system and eliminate waste. T-regs were only discovered there in recent years.

This new research shows that the immune system actually uses the meninges to communicate with distant neurons that detect sensation on the skin.

Further experiments revealed a relationship between T-regs and female hormones that no one had seen before: Estrogen and progesterone were prompting the cells to churn out painkilling enkephalin.

This work could be particularly helpful for women who have gone through menopause and no longer produce estrogen and progesterone, many of whom experience chronic pain.

 Élora Midavaine et al, Meningeal regulatory T cells inhibit nociception in female mice, Science (2025). DOI: 10.1126/science.adq6531. www.science.org/doi/10.1126/science.adq6531

Comment by Dr. Krishna Kumari Challa on April 6, 2025 at 8:33am

Statistical modeling found a non-significant reduced risk during the first two years of treatment (HR, 0.77; 95% CI, 0.59–1.01), and a non-significant effect beyond two years (HR, 1.06; 95% CI, 0.76–1.50). Similar trends were observed in secondary outcomes.

In subgroup analyses, treatment effect varied by hypertension status, with a significant reduced risk in participants without hypertension (HR, 0.63; 95% CI, 0.44–0.92) and no significant findings among those with hypertension (HR, 1.04; 95% CI, 0.80–1.36).

Researchers concluded that cocoa extract supplementation had no significant overall effect on AMD risk over a median 3.6-year period. Although researchers did not rule out a possible early benefit trend, the findings do not support cocoa flavanol supplementation as a preventive strategy for AMD.

However, the researchers acknowledge that this 's a limited sample study. 

William G. Christen et al, Cocoa Flavanol Supplementation and Risk of Age-Related Macular Degeneration, JAMA Ophthalmology (2025). DOI: 10.1001/jamaophthalmol.2025.0353

Comment by Dr. Krishna Kumari Challa on April 6, 2025 at 8:32am

Cocoa extract fails to prevent age-related vision loss, clinical trial finds

Clinical research reports no significant long-term benefit of cocoa flavanol supplementation in preventing age-related macular degeneration (AMD). The paper is published in the journal JAMA Ophthalmology.

AMD is a progressive retinal disease and the most common cause of severe vision loss in adults over age 50. AMD damages the macula, the central part of the retina responsible for sharp, detailed vision. While peripheral sight is typically preserved, central vision loss can impair reading, driving, facial recognition, and other quality of life tasks. Abnormalities of blood flow in the eye are associated with the occurrence of AMD.

Cocoa flavanols are a group of naturally occurring plant compounds classified as flavonoids, found primarily in the cocoa bean. These bioactive compounds have been studied for their vascular effects, including improved endothelial function and enhanced nitric oxide production, which contribute to vasodilation and circulatory health. Previous trials have shown that moderate intake of cocoa flavanols may lower blood pressure, improve lipid profiles, and reduce markers of inflammation, suggesting a role in mitigating cardiovascular and related vascular conditions.

In the study titled "Cocoa Flavanol Supplementation and Risk of Age-Related Macular Degeneration: An Ancillary Study of the COSMOS Randomized Clinical Trial," researchers conducted a double-blind, placebo-controlled randomized clinical trial to examine whether daily supplementation with cocoa extract prevents the development or progression of AMD.

A cohort of 21,442 U.S. adults (12,666 women aged 65 and older, and 8,776 men aged 60 and older) were recruited, with eligibility criteria requiring discontinuation of non-trial cocoa supplements and multivitamins for the 3.6-year duration of the trial. COSMOS included its own multivitamin supplement as one arm of the trial.

Daily supplementation consisted of 500 mg cocoa flavanols containing 80 mg (−)-epicatechin. Randomization assigned participants to either the cocoa extract or a matching placebo group. AMD outcomes were identified through self-reported diagnoses, verified through medical record confirmation. Compliance biomarkers confirmed a threefold increase in flavanol metabolite levels in the cocoa group.

A total of 344 participants experienced a confirmed AMD event, including 316 incident cases and 28 cases of progression. Incidence was 1.5% in the cocoa extract group and 1.7% in the placebo group.

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