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Comment by Dr. Krishna Kumari Challa on November 28, 2023 at 10:38am

How climate change impacts health

Extreme heat, air pollution and the increasing spread of deadly infectious diseases are just some of the reasons why the World Health Organization has called climate change the single biggest health threat facing humanity.

Global warming must be limited to the Paris Agreement target of 1.5 degrees Celsius "to avert catastrophic health impacts and prevent millions of climate change-related deaths", according to the WHO.

However, under current national carbon-cutting plans, the world is on track to warm up to 2.9°C this century, the UN said this week.

While no one will be completely safe from the effects of climate change, experts expect that most at risk will be children, women, the elderly, migrants and people in less developed countries which have emitted the least planet-warming greenhouse gases.

This year is widely expected to be the hottest on record. And as the world continues to warm, even more frequent and intense heat waves are expected to follow.

Part 1

Comment by Dr. Krishna Kumari Challa on November 28, 2023 at 10:26am

Not just meteorite: New clues about the demise of dinosaurs

What wiped out the dinosaurs? A meteorite plummeting to Earth is only part of the story, a new study suggests. Climate change triggered by massive volcanic eruptions may have ultimately set the stage for the dinosaur extinction, challenging the traditional narrative that a meteorite alone delivered the final blow to the ancient giants.

Researchers delved into volcanic eruptions of the Deccan Traps—a vast and rugged plateau in Western India formed by molten lava. Erupting a staggering 1 million cubic kilometers of rock, it may have played a key role in cooling the global climate around 65 million years ago. The work took researchers around the world, from hammering out rocks in the Deccan Traps to analyzing the samples in England and Sweden. 

In the lab, the scientists estimated how much sulfur and fluorine was injected into the atmosphere by massive volcanic eruptions in the 200,000 years before the dinosaur extinction.

Remarkably, they found the sulfur release could have triggered a global drop in temperature around the world—a phenomenon known as a volcanic winter.

The research demonstrates that climatic conditions were almost certainly unstable, with repeated volcanic winters that could have lasted decades, prior to the extinction of the dinosaurs. This instability would have made life difficult for all plants and animals and set the stage for the dinosaur extinction event. 

Sara Callegaro et al, Recurring volcanic winters during the latest Cretaceous: Sulfur and fluorine budgets of Deccan Traps lavas, Science Advances (2023). DOI: 10.1126/sciadv.adg8284

Comment by Dr. Krishna Kumari Challa on November 28, 2023 at 10:01am

Study unveils the engagement of different cortical networks while humans are unconscious

States of unconsciousness, such as those that occur during sleep or while under the effect of anesthesia, have been the focus of countless past neuroscience studies. While these works have identified some brain regions that are active and inactive when humans are unconscious, the precise contribution of each of these regions to consciousness remains largely unclear.

Researchers recently carried out a study aimed at better understanding the activity of different regions of the cortex, the outer layer of the mammalian brain, during different states of unconsciousness, namely sleep and general anesthesia. Their paper, published in Neuron, identifies distinct cortical networks that are engaged during different states of unconsciousness.

What happens in the human brain when we are unconscious? And, what happens when we cannot be awakened?

This recent study on the states of unconsciousness focuses on sleep versus general anesthesia induced by the drug propofol.

The researchers carried out their study on patients diagnosed with epilepsy who had electrodes implanted in their brains as part of their medical treatment. By recording brain activity inside the brain, these electrodes help doctors monitor and treat epileptic seizures. 

They found that, compared to when they were awake, during sleep the brain was uniformly affected across patients, presenting simpler and reduced brain connections, as well as larger variability in the recorded activity.

All measures were more pronounced during propofol-induced anesthesia, but the brain involvement was not uniform; the changes in prefrontal regions were particularly prominent.

This indicates that during different forms of unconsciousness distinct parts of the brain are involved in different ways. These new findings in turn imply that going from unconscious to conscious may use different mechanisms depending on the nature of the unconscious state.

 Rina Zelmann et al, Differential cortical network engagement during states of un/consciousness in humans, Neuron (2023). DOI: 10.1016/j.neuron.2023.08.007

Comment by Dr. Krishna Kumari Challa on November 27, 2023 at 1:18pm

Bacteria store 'memories' and pass them on for generations, study finds

Scientists have discovered that bacteria can create something like memories about when to form strategies that can cause dangerous infections in people, such as resistance to antibiotics and bacterial swarms when millions of bacteria come together on a single surface. The discovery—which has potential applications for preventing and combatting bacterial infections and addressing antibiotic-resistant bacteria—relates to a common chemical element bacterial cells can use to form and pass along these memories to their progeny over later generations.

Researchers found that E. coli bacteria use iron levels as a way to store information about different behaviours that can then be activated in response to certain stimuli.

Scientists had previously observed that bacteria that had a prior experience of swarming (moving on a surface as a collective using flagella) improve subsequent swarming performance.

Bacteria don't have neurons, synapses or nervous systems, so any memories are not like the ones we have. They are more like information stored on a computer.

Bacteria don't have brains, but they can gather information from their environment, and if they have encountered that environment frequently, they can store that information and quickly access it later for their benefit.

It all comes back to iron, one of the most abundant elements on Earth. Singular and free-floating bacteria have varying levels of iron. Scientists observed that bacterial cells with lower levels of iron were better swarmers. In contrast, bacteria that formed biofilms, dense, sticky mats of bacteria on solid surfaces, had high levels of iron in their cells. Bacteria with antibiotic tolerance also had balanced levels of iron. These iron memories persist for at least four generations and disappear by the seventh generation.

Before there was oxygen in the Earth's atmosphere, early cellular life was utilizing iron for a lot of cellular processes. Iron is not only critical in the origin of life on Earth, but also in the evolution of life. It makes sense that cells would utilize it in this way.

Souvik Bhattacharyya et al, A heritable iron memory enables decision-making in Escherichia coli, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2309082120

Comment by Dr. Krishna Kumari Challa on November 27, 2023 at 1:05pm

The bilingual brain may be better at ignoring irrelevant information

People who speak two languages may be better at shifting their attention from one thing to another compared to those who speak one, according to a study published this month in the journal Bilingualism: Language and Cognition.

The study examined differences between bilingual and monolingual individuals when it comes to attentional control and ignoring information that isn't important at the time. 

Our results showed that bilinguals seem to be more efficient at ignoring information that's irrelevant, rather than suppressing—or inhibiting information. One explanation for this is that bilinguals are constantly switching between two languages and need to shift their attention away from the language not in use.

For example, if an English- and Spanish-speaking person is having a conversation in Spanish, both languages are active, but English is put on hold but always ready to be deployed as needed. Numerous studies have examined the distinctions between the two groups in broad cognitive mechanisms, which are mental processes that our brains use, like memory, attention, problem-solving, and decision-making.

The effects of speaking two languages on a person's cognitive control is often debated. Some of the literature says these differences aren't so pronounced, but that could be because of the tasks linguists use to research differences between bilinguals and monolinguals.

Now what about people who can speak several languages?

Grace deMeurisse et al, Bilingual attentional control: Evidence from the Partial Repetition Cost paradigm, Bilingualism: Language and Cognition (2023). DOI: 10.1017/S1366728923000731

Comment by Dr. Krishna Kumari Challa on November 26, 2023 at 12:21pm

Scientists finally work out what causes itching

Comment by Dr. Krishna Kumari Challa on November 26, 2023 at 11:59am

Scientists Find 'Kill Switch' That Activates Cancer Cell Death in The Lab

Scientists have figured out a way to detonate the 'doors' that lead to the heart of cancerous tumors, blowing them wide open for drug treatments.

The strategy works by triggering a 'timer bomb' on the cells that line a tumor's associated blood vessels.

These vessels control access to the tumor tissue, and until they are opened, engineered immune cells can't easily gain entry to the cancer to fight it off. The timer bomb on these cells is actually a 'death' receptor, called Fas (or CD95). When activated by the right antibody, it triggers the programmed death of that cell.

In recent experiments using mouse models and human cell lines, scientists have at last identified specific antibodies that, when attached to Fas receptors, effectively trigger self-implosion. now that we've identified this epitope, there could be a therapeutic path forward to target Fas in tumors. The antibody that binds to this epitope (a specific part of the death receptor), essentially represents the kill switch for the cell. Once this immune checkpoint is blown open, other cancer therapies, like CAR-T therapy, can gain access to more of their targets, which are often clumped together and hidden within the tumor. CAR-T therapy works by programming a person's own white blood cells, called T-cells, to bind to and attack specific types of cancerous cells. These tailored immune cells, however, cannot usually get past the 'bystander' cells that lack the recognisable antigens usually used to target tumor cells. As a result, CAR-T therapy has only been approved to treat blood cancers or leukemia. It fails to provide consistent success against solid tumors till now. In recent experiments , scientists developed two engineered antibodies that were "supremely effective" at attaching to Fas receptors and causing bystander cells to self-implode. This was true in ovarian cancer models and many other tumor cell lines tested in the lab. The Fas ligand developed by researchers was able to engage two critical parts of the Fas receptor, which researchers say should be investigated further. These parts hold potential as future drug targets.

https://www.nature.com/articles/s41418-023-01229-7

Comment by Dr. Krishna Kumari Challa on November 26, 2023 at 11:52am

Death by Stem Cell: Developing New Cancer Therapies

Engineering stem cells to deliver cancer therapeutics directly to tumors, thereby increasing their efficacy.

While chemotherapy, surgery, and radiation therapy are traditional cancer treatments that can be applied individually or in combination, a patient’s response to these approaches depends on cancer type, location, heterogeneity, and drug resistance.2 Consequently, researchers need to develop novel therapies and delivery methods.

Some researchers are developing cancer therapeutics that use stem cells as delivery vectors to treat primary and metastatic brain and lung cancers. In a recently published Science Translational Medicine paper, some of them  showed an allogeneic twin stem cell system carrying oncolytic viral particles and immunomodulators to treat brain metastases.  A few weeks later, they also published a Stem Cells Translational Medicine paper, where they engineered mesenchymal stem cells to secrete a bi-functional molecule targeting two receptors in lung tumors, leading to cancer cell death.

1. Siegel RL, et al. Cancer statistics, 2023. CA Cancer J Clin. 2023;73(1):17-48.
2.  Debela DT, et al. New approaches and procedures for cancer treatment: Current perspec.... SAGE Open Med. 2021;9.
3.  Kanaya N, et al. Gene-edited and -engineered stem cell platform drives immunotherapy.... Sci Transl   Med. 2023;15(698):eade8732.
4.  Moleirinho S, et al. Fate and efficacy of engineered allogeneic stem cells targeting cel.... Stem Cells Transl Med. 2023;12(7):444-458.

Comment by Dr. Krishna Kumari Challa on November 26, 2023 at 11:22am

Plastic waste in the water might be stopping, or interrupting, some shrimp-like creatures from reproducing
In a unique study, published in the journal Environmental Pollution,the ability of "shrimp-like" creatures to reproduce successfully was found to be compromised by chemicals found in everyday plastics.

Research showed that little critters, known as marine amphipod Echinogammarus marinus, changed their mating behavior when exposed to toxic plastic additives.

Until now, most research into plastic pollution has focused on visual plastics; what can get trapped in plastics and the dangers of ingesting large particles. Scientists now have taken a different approach and investigated the chemicals that are used as ingredients in plastics.
This unsuccessful mating behavior has serious repercussions, not only for the species being tested but potentially for the population as a whole. These animals form pairs to reproduce. Once they were exposed to a chemical, they would break apart from their mate and take much longer—in some cases days—to re-pair, and sometimes not at all.
These creatures make up a substantial amount of the diet of fish and birds. If they are compromised it will have an effect on the whole food chain.
There are more than 350,000 chemicals in use around the world in everyday products. Ten thousand of these are used to enhance plastics. Chemicals can be used to make plastics more flexible, add color, give sun protection or make plastic flameproof. About one-third of these chemicals are known to be toxic to human's immune, nervous or reproductive systems.
Although the animals we tested were exposed to much higher concentrations than you would normally find in the environment, the results indicate these chemicals can affect sperm count.

Bidemi Green-Ojo et al, Evaluation of precopulatory pairing behaviour and male fertility in a marine amphipod exposed to plastic additives, Environmental Pollution (2023). DOI: 10.1016/j.envpol.2023.122946

Comment by Dr. Krishna Kumari Challa on November 25, 2023 at 11:07am

Reactivating silenced fetal hemoglobin genes could counter sickle cell–related diseases

Researchers from multiple institutions  have found a way to use gene editing to reactivate dormant fetal oxygen-transporting proteins in adult blood cells to potentially reverse a wide range of blood disorders.

In a paper, "Base editing of the HBG promoter induces potent fetal hemoglobin expression with no detectable off-target mutations in human HSCs," published in Cell Stem Cell, the team compares gene editing techniques while formulating a method that could have important clinical applications.

Fetal gamma (γ) globin is normally replaced by adult (β) hemoglobin during development. In an odd quirk of evolution, only humans and a few types of monkeys are known to switch from γ to β gene expression. The genes producing the fetal hemoglobin become silenced and dormant after the genetic switch by repressors such as BCL11A and ZBTB7A, whose binding motifs have been identified as targets for reactivation. β-hemoglobinopathies, including β-thalassemia and sickle cell disease, result from mutations in the HBB gene, leading to impaired β-globin production and resulting in anemia, impaired oxygen delivery to tissues and possible multi-organ tissue damage. The researchers experimentally discovered that reactivating γ-globin expression could be developed into a universal therapeutic strategy for these conditions.

Wenyan Han et al, Base editing of the HBG promoter induces potent fetal hemoglobin expression with no detectable off-target mutations in human HSCs, Cell Stem Cell (2023). DOI: 10.1016/j.stem.2023.10.007

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