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Comment by Dr. Krishna Kumari Challa on April 8, 2025 at 8:56am

Obesity severity tied to increased risk across 16 common conditions

New research has found that obesity, particularly severe obesity, is strongly associated with the incidence of 16 common health outcomes. Associations remained consistent across sex and racial groups. Strong associations were observed for obstructive sleep apnea, type 2 diabetes, and metabolic dysfunction-associated steatotic liver disease.

Obesity is a risk factor for adverse health outcomes involving multiple organ systems. Prior studies have analyzed conditions individually, limiting understanding of obesity's total health burden. External validity has also been limited by underrepresentation of individuals with class III obesity and of diverse demographic groups.

In the study, "Associations between Class I, II, or III Obesity and Health Outcomes," published in NEJM Evidence, researchers conducted a longitudinal cohort study to understand how different levels of obesity relate to a wide array of health conditions across a diverse U.S. population.

Participants contributed electronic health records, physical measurements, and survey data. Body mass index (BMI) was calculated at enrollment and used to classify individuals as normal weight, overweight, or obese, with further stratification into obesity classes I, II, and III.

Sixteen pre-identified health conditions were evaluated: hypertension, type 2 diabetes, hyperlipidemia or dyslipidemia, heart failure, atrial fibrillation, atherosclerotic cardiovascular disease, chronic kidney disease, pulmonary embolism, deep vein thrombosis, gout, liver disease linked to metabolic dysfunction, biliary calculus, obstructive sleep apnea, asthma, gastroesophageal reflux disease, and osteoarthritis.

Part 1

Comment by Dr. Krishna Kumari Challa on April 7, 2025 at 10:15am

Urban birds host drug-resistant bacteria

Indian cormorants (Phalacocorax fuscicollis) can spread antimicrobial-resistant bacteria in their droppings. Intrigued by the smell of cormorant droppings, veterinary microbiologist Siddhartha Narayan Joardar and his team analysed some of the bird poo and found a strain of E. coli that produced enzymes that helped it resist certain antibiotics. The birds probably pick up the bacterium by eating fish from ponds contaminated by human wastewater, the team suggests. “Growing evidence shows the presence of antimicrobial-resistant bacteria in common urban birds,” says Joardar, which poses a public health threat if it spills over into humans.

https://www.nature.com/articles/d44151-025-00042-0?utm_source=Live+...

https://www.ijah.in/upload/snippet/707_84.pdf

Comment by Dr. Krishna Kumari Challa on April 7, 2025 at 8:47am

When looking at specific dementia subtypes, all unmarried participants also showed reduced risk for Alzheimer's disease and Lewy body dementia. In contrast, no consistent associations were observed for vascular dementia or frontotemporal lobar degeneration in fully adjusted models. Divorced and never-married groups were also less likely to progress from mild cognitive impairment to dementia.

Risk patterns appeared slightly stronger among men, younger individuals, and participants referred to clinics by health professionals. Yet stratified analyses showed minimal variation, suggesting that the associations held across a wide range of demographic and clinical subgroups.

Researchers concluded that unmarried individuals, particularly those who were divorced or never married, had a lower risk of developing dementia than those who remained married. These associations persisted even after adjusting for physical and mental health, lifestyle factors, genetics, and differences in clinical referral and evaluation.
Alzheimer's disease and Lewy body dementia were higher in married participants. Risk of progression from mild cognitive impairment to dementia was also higher.
The findings contrast with prior studies linking unmarried status to increased dementia risk and offer new evidence on how relationship status may relate to cognitive outcomes when diagnosis is measured under standardized conditions.

Selin Karakose et al, Marital status and risk of dementia over 18 years: Surprising findings from the National Alzheimer's Coordinating Center, Alzheimer's & Dementia (2025). DOI: 10.1002/alz.70072

Part 2

Comment by Dr. Krishna Kumari Challa on April 7, 2025 at 8:45am

Marriage linked to higher dementia risk in older adults, 18-year study finds

This one is going to surprise you.

Researchers found that older adults who were divorced or never married had a lower risk of developing dementia over an 18-year period compared to their married peers. Findings suggest that being unmarried may not increase vulnerability to cognitive decline, contrary to long-held beliefs in public health and aging research.

Marriage is often linked to better health outcomes and longer life, but evidence connecting marital status to dementia risk remains inconsistent. 

Prior research has not consistently addressed how marital status relates to specific causes of dementia or how factors such as sex, depression, or genetic predisposition may influence these associations.

In the study, "Marital status and risk of dementia over 18 years: Surprising findings from the National Alzheimer's Coordinating Center," published in Alzheimer's & Dementia, researchers conducted an 18-year cohort study to understand whether marital status was associated with dementia risk in older adults.

More than 24,000 participants without dementia at baseline were enrolled from over 42 Alzheimer's Disease Research Centers across the United States through the National Alzheimer's Coordinating Center. Annual clinical evaluations were conducted by trained clinicians using standardized protocols to assess cognitive function and determine diagnoses of dementia or mild cognitive impairment.

To assess long-term risk, researchers followed participants for up to 18.44 years, yielding over 122,000 person-years of data. Marital status at baseline was categorized as married, widowed, divorced, or never married.

Dementia risk was analyzed using Cox proportional hazards regression, with married participants serving as the reference group. The models incorporated demographic characteristics, mental and physical health, behavioral history, genetic risk factors, and diagnostic as well as enrollment variables.

Compared to married participants, divorced or never married showed a consistently lower risk of developing dementia over the study period. Dementia diagnoses occurred in 20.1% of the overall sample. Among married participants, 21.9% developed dementia during the study period. Incidence was identical among widowed participants at 21.9% but notably lower for divorced (12.8%) and never-married participants (12.4%).

Hazard ratios showed a reduced risk for all three unmarried groups. In initial models adjusting only for age and sex, divorced individuals had a 34% lower risk of developing dementia (HR = 0.66, 95% CI = 0.59–0.73), never-married individuals had a 40% lower risk (HR = 0.60, 95% CI = 0.52–0.71), and widowed individuals had a 27% lower risk (HR = 0.73, 95% CI = 0.67–0.79).

These associations remained significant for the divorced and never-married groups after accounting for health, behavioral, genetic, and referral-related factors. The association for widowed participants weakened and was no longer statistically significant in the fully adjusted model.
Part 1

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.

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