Comment

Comment by Dr. Krishna Kumari Challa on October 31, 2023 at 12:59pm

Asteroid dust caused 15-year winter that killed dinosaurs: Study

Around 66 million years ago, an asteroid bigger than Mount Everest smashed into Earth, killing off three quarters of all life on the planet—including the dinosaurs.

But exactly how the impact of the asteroid Chicxulub caused all those animals to go extinct has remained a matter of debate till now.

The leading theory recently has been that sulfur from the asteroid's impact—or soot from global wildfires it sparked—blocked out the sky and plunged the world into a long, dark winter, killing all but the lucky few.

However research published recently based on particles found at a key fossil site reasserted an earlier hypothesis: that the impact winter was caused by dust kicked up by the asteroid.

Fine silicate dust from pulverized rock would have stayed in the atmosphere for 15 years, dropping global temperatures by up to 15 degrees Celsius, researchers said in a study in the journal Nature Geoscience.

 Cem Berk Senel et al, Chicxulub impact winter sustained by fine silicate dust, Nature Geoscience (2023). DOI: 10.1038/s41561-023-01290-4

Comment by Dr. Krishna Kumari Challa on October 31, 2023 at 12:30pm

Scientists isolate 'pre-emerging' bat coronavirus but also identify existing medication that potently neutralizes it

Repeated outbreaks of bat-derived coronaviruses among humans and other mammals have heightened the need for a broad range of therapeutics—monoclonal antibodies and antivirals—treatments that can come immediately "off-the-shelf" to address newly-emerging zoonotic threats.

A groundbreaking series of experiments by scientists at collaborating research centers has not only identified a "pre-emerging bat coronavirus," but investigators have additionally demonstrated that an off-the-shelf monoclonal antibody neutralized it potently. Additionally, in vitro tests of widely-used antivirals were also effective against the virus, researchers found.

The bat-derived coronavirus is more specifically known as BtCoV-422. And a neutralizing monoclocal antibody developed to treat Middle East respiratory syndrome coronavirus—MERS-CoV—has been available for years and is known as mAb JC57-11. MERS-CoV is a bat-derived zoonotic virus that infects dromedary camels, the animals that transmit the virus to people. BtCoV-422 is genetically similar to MERS-CoV.

Writing in Science Translational Medicine, investigators  who underscored a deceptively simple principle: the types of countermeasures that have worked against other coronaviruses, such as MERS-CoV and SARS-CoV-2, should impact BtCoV-422. But while investigators found that most MERS-CoV–neutralizing monoclonal antibodies had very limited activity against the virus, mAb JC57-11 delivered a powerful one-two punch.

Longping V. Tse et al, A MERS-CoV antibody neutralizes a pre-emerging group 2c bat coronavirus, Science Translational Medicine (2023). DOI: 10.1126/scitranslmed.adg5567

Comment by Dr. Krishna Kumari Challa on October 30, 2023 at 10:00am

Volcanic eruptions found to dampen Indian Ocean El Niño events 

Volcanic eruptions occurring in tropical regions (23°N/S of the equator) have been linked to abrupt disruption of global-scale climate cycles in the Indian Ocean over the last 1 million years in new research published in Geophysical Research Letters. El Niño Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) are ocean-atmosphere climate interactions that were found to be disrupted for almost a decade before returning to pre-eruption baseline levels, and the effect increases with greater eruption intensity.

Benjamin H. Tiger et al, Tropical Volcanic Eruptions and Low Frequency Indo‐Pacific Variability Drive Extreme Indian Ocean Dipole Events, Geophysical Research Letters (2023). DOI: 10.1029/2023GL103991

Comment by Dr. Krishna Kumari Challa on October 30, 2023 at 9:52am

In previous work by scientists, these mutations have been shown to have an impact on diseases such as inflamatoy bowl disease. In this new study, researchers explored if the same was true for psoriasis.

Psoriasis is a chronic inflammatory immune-mediated disease that causes patches of skin to become flaky or sore. The current cause of the condition is unknown and it is estimated that 125 million people worldwide—2% to 3% of the total population—have psoriasis.

This team took skin samples from the forearms of 111 people with psoriasis, taking samples from psoriasis patches and healthy skin. They used laser capture microdissection to isolate 1,182 samples, which were then analyzed by whole genome or exome sequencing.

They found minimal differences in the types of mutations seen in healthy skin versus psoriasis patches and only a slight increase in the number of mutations. In addition to this, no functional differences were seen between psoriasis and non-psoriasis tissue, suggesting that the condition is not linked to a specific somatic mutation in the skin.

The team identified four new driver mutations that gave skin cells an advantage over their neighbors, all found in both psoriasis patches and other skin tissue. They also found a mutational signature linked with the use of psoralens, a compound sometimes used as part of a treatment for psoriasis flare-ups. However, these mutations were found in patients who had been prescribed psoralens along with those who hadn't, suggesting that it could have come from environmental exposure.

 Sigurgeir Olafsson et al, Effects of psoriasis and psoralen exposure on the somatic mutation landscape of the skin, Nature Genetics (2023). DOI: 10.1038/s41588-023-01545-1

Part 2

Comment by Dr. Krishna Kumari Challa on October 30, 2023 at 9:50am

Psoriasis not caused by spontaneous mutations : Study

Psoriasis—a chronic skin condition—is not caused or spread by spontaneous genetic mutations in the skin, new research suggests.

Researchers sequenced skin samples from 111 people with psoriasis. They didn't find any mutated genes in the psoriatic patches that weren't also mutated in the individual's unaffected skin tissue. The study, published in Nature Genetics, suggests that unlike other inflammatory diseases, such as inflammatory bowel disease or chronic liver disease, somatic mutations were not responsible for the start or spread of psoriasis.  

Confirming that psoriasis is not caused by any somatic mutations enables researchers to continue to explore other avenues.

Over time, all cells in our bodies will accumulate mutations, known as somatic mutations. These can arise from replication errors, chemicals, or environmental factors. While some of these mutations can lead to cancer, many are harmless. When a mutation gives the cell an advantage over its neighbors, it is known as a driver mutation, and this allows the mutated cells to grow and spread.

Recently, research has begun to explore the possibility of driver mutations causing non-cancerous diseases by impacting the function of the tissue or influencing the spread of disease through the body.

Part 1

Comment by Dr. Krishna Kumari Challa on October 30, 2023 at 9:41am

Nanoparticles found to be effective for the treatment of rheumatoid arthritis

A team of scientists has developed a new solution for the treatment of rheumatoid arthritis (RA).

RA is a chronic disease that, unfortunately, has no cure. The disease triggers a mix of troublesome symptoms like inflamed joints, harmful cytokines, and immune system imbalances, which work together to create a relentless cycle of worsening symptoms. While targeting some of these factors can provide short-term relief, others remain unresolved, leading to a frustrating cycle of remission and flare-ups.

One of the major hurdles in RA treatment is the inability to restore the immune system to its healthy state. This leaves the body unable to control the continuous production of harmful substances like reactive oxygen species (ROS) and inflammatory cytokines, leading to persistent inflammation and discomfort. In essence, the ideal treatment for RA should not only provide immediate relief from inflammation and symptoms but also address the root cause by restoring the immune system to its normal, balanced state.

The new work involves immobilizing ceria nanoparticles (Ce NPs) onto mesenchymal stem cell-derived nanovesicles (MSCNVs). Both of these components can hinder different pathogenic factors, allowing them to work both individually and cooperatively to achieve a comprehensive treatment.

Ce NPs can scavenge the overproduced ROS in RA-inflicted knee joints. They also induce polarization of M1 macrophages into M2, achieving immediate relief of inflammation and symptoms. MSCNVs deliver immunomodulatory cytokines, which turn dendritic cells (DC) into tolerogenic dendritic cells (tDCs). This consequently generates regulatory T cells for long-term immune tolerance. In short, this approach aims to bridge both innate and adaptive immunity to achieve both short-term pain relief, as well as convert the tissue environment into an immune-tolerant state to prevent the recurrence of symptoms.

Researchers confirmed the efficacy of this approach using a collagen-induced arthritis mouse model. The Ce-MSCNV system was able to comprehensively treat and prevent RA by simultaneously relieving the immediate and restoring T cell immunity. Supporting data suggest that improvement in conditions can be achieved after only a single-dose treatment.

The mice treated with the Ce-MSCNV combination fared far better compared to the ones only treated using the Ce NP or MSCNV group. This clearly demonstrates the synergy between anti-inflammation and immunomodulation and underlines the importance of the combined therapy for effective RA treatment. In addition, Ce-MSCNV administration prior to booster injection markedly reduced the incidence and severity of symptoms, supporting the prophylactic potential of these nanoparticles.

Koo Sagang et al, Ceria-vesicle nanohybrid therapeutic for modulation of innate and adaptive immunity in a collagen-induced arthritis model, Nature Nanotechnology (2023). DOI: 10.1038/s41565-023-01523-y

Comment by Dr. Krishna Kumari Challa on October 29, 2023 at 12:32pm

For instance, between 2003 and 2016, females represented less than 10% of participants in lung and pancreatic cancer trials, despite accounting for more than 40% of the diagnoses. In 2018, women made up only 38% of the 5,157 people who participated in oncology trials that led to the approval of new drugs.

,The insufficient recruitment of female participants has historically been due to concerns that regular monthly hormonal fluctuations might affect the findings and that the intervention being tested could lead to fetal abnormalities in those capable of pregnancy.

Some gender-related misconceptions have also played a part. Research suggests some trial sponsors and clinicians believe that women bring complexity to clinical trials and that their 'increased emotions and sensitivity' may affect how they report their symptoms. However, these excuses are no longer considered valid.

For things to improve, it is crucial for scientists to develop a deeper understanding of the specific influences of sex differences in different cancer types.

 Why outcomes are worse in females. Is it just due to diagnosis occurring at a later stage, when treatment is less likely to be effective, or are there other factors at play?

Scientists should focus on immunology, as male and female hormones have quite different immunological effects.

Sex-specific immunological changes are important to investigate because they dictate how the genomics of tumors evolve and how cancer learns to escape the immune response.

Paul Toren et al, The sex gap in bladder cancer survival—a missing link in bladder cancer care?, Nature Reviews Urology (2023). DOI: 10.1038/s41585-023-00806-2

Part 2

**

Comment by Dr. Krishna Kumari Challa on October 29, 2023 at 12:29pm

We can't defeat cancer without acknowledging the differences between men and women, say scientists
For generations, the medical community has used the "standard human"—a 70-kilogram male—to guide education, research and practice. This means that for many conditions, although the recommended type, dosage and duration of treatment may be effective for the group of males who happen to weigh close to 70 kg, they might be far from optimal for most of the population, including all females.

In cancer, multiple bodily factors contribute to how the disease develops, progresses and responds to treatment, and many of these factors relate to sex.

Sex differences in cancer are not technically a new insight, but they have historically been somewhat overlooked. However, researchers have recently started to uncover some of the mechanisms behind how a person's sex affects their experience of cancer. The realization that such knowledge may one day make it possible to improve outcomes for all patients has given more scientists the impulse to delve deeper into this area of research.
The anatomical differences between males and females are well known. Males typically have higher muscle and bone mass, a lower fat mass and a visibly different skeletal shape. Males also have a higher body water content, which, alongside differences in metabolism and fat mass, can affect how the body responds to and breaks down cancer-killing drugs.

Some of these differences are due to males having one Y chromosome and one X chromosome, rather than the two X chromosomes in the female body. In fact, research suggests that genetics plays a very significant part, indicating that up to one third of the genome might be expressed differently by males and females.

Females and males also have different sex hormones, and these influence the blood vessels, immune cells, signaling molecules and other features that surround tumors, known as the tumor microenvironment. For types of cancer that are dependent on or sensitive to hormones, these chemicals can promote the growth and spread of the disease.

Researchers have also uncovered differences between male and female immune responses. They believe that these are typically stronger in females, who tend to clear disease-causing organisms such as bacteria more quickly from the body and be better protected by vaccinations. Conversely, females are often more susceptible to inflammatory and autoimmune conditions, some of which are associated with an increased risk of cancer.

All of these differences mean that, although males are more likely than females to get cancer and to have a poor outcome, females are 34 percent more likely to experience side effects from cancer treatments, including chemotherapy, targeted therapy and immunotherapy.
A big part of the problem is that treatment recommendations are based on the findings of clinical trials, which are only generalizable if the trial participants are representative of the relevant patient population. This is an issue because females are generally under-represented in clinical trials.
Part 1

Comment by Dr. Krishna Kumari Challa on October 29, 2023 at 12:09pm

However, nature is chaotic, and not all physical systems are bound by these symmetries. So-called non-reciprocal interactions show up in unruly systems made up of flocking birds, particles in fluid – and swimming sperm.

These motile agents move in ways that display asymmetric interactions with the animals behind them or the fluids that surround them, forming a loophole for equal and opposite forces to skirt Newton's third law.
Because birds and cells generate their own energy, which gets added to the system with each flap of their wings or whip of their tails, the system is thrust far from equilibrium, and the same rules don't apply.
---
Scientists analyzed experimental data on human sperm and also modeled the motion of green algae, Chlamydomonas. Both swim using thin, bendy flagella that protrude from the cell body and change shape, or deform, to drive the cells forward.

Highly viscous fluids would typically dissipate a flagellum's energy, preventing a sperm or single-celled algae from moving much at all. And yet somehow, the elastic flagella can propel these cells along without provoking a response from their surroundings.

The researchers found that sperm tails and algal flagella have an 'odd elasticity', which allows these flexible appendages to whip about without losing much energy to the surrounding fluid.
But this property of odd elasticity didn't fully explain the propulsion from the flagella's wave-like motion. So from their modeling studies, the researchers also derived a new term, an odd elastic modulus, to describe the internal mechanics of flagella.
The findings could help in the design of small, self-assembling robots that mimic living materials, while the modeling methods could be used to better understand the underlying principles of collective behaviour.

https://journals.aps.org/prxlife/abstract/10.1103/PRXLife.1.023002

Part 2

Comment by Dr. Krishna Kumari Challa on October 29, 2023 at 12:06pm

Scientists Caught Sperm Defying One of The Major Laws of Physics

With their whip-like tails, human sperm propel themselves through viscous fluids, seemingly in defiance of Newton's third law of motion, according to a new study that characterizes the motion of these sex cells and single-celled algae.

Scientists investigated these non-reciprocal interactions in sperm and other microscopic biological swimmers, to figure out how they slither through substances that should, in theory, resist their movement.

When Newton conceived his now-famed laws of motion in 1686, he sought to explain the relationship between a physical object and the forces acting upon it with a few neat principles that, it turns out, don't necessarily apply to microscopic cells wriggling through sticky fluids.

Newton's third law can be summed up as "for every action, there is an equal and opposite reaction". It signifies a particular symmetry in nature where opposing forces act against each other. In the simplest example, two equal-sized marbles colliding as they roll along the ground will transfer their force and rebound based on this law.

However, nature is chaotic, and not all physical systems are bound by these symmetries. So-called non-reciprocal interactions show up in unruly systems made up of flocking birds, particles in fluid – and swimming sperm.

These motile agents move in ways that display asymmetric interactions with the animals behind them or the fluids that surround them, forming a loophole for equal and opposite forces to skirt Newton's third law.
----
Part 1

• ‹ Previous
• 1
• …
• 247
• 248
• 249
• 250
• 251
• …
• 1006
• Next ›
• Page