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Comment by Dr. Krishna Kumari Challa on November 9, 2023 at 8:10am

Researchers identify brain network that is uniquely activated through injection vs. oral drug use

Understanding the brain mechanisms that underlie addiction is crucial for informing prevention interventions, developing new therapies for substance use disorders, and addressing the overdose crisis.

Results from a new clinical trial suggest that a group of brain regions known as the "salience network" is activated after a drug is taken intravenously, but not when that same drug is taken orally.

When drugs enter the brain quickly, such as through injection or smoking, they are more addictive than when they enter the brain more slowly, such as when they are taken orally. However, the brain circuits underlying these differences are not well understood. This study offers new information that helps explain what may be causing this difference.

People who smoke or inject drugs—two methods that deliver drugs to the brain quickly—often report doing so to get faster relief from withdrawal or to experience euphoria more quickly. However, drug smoking and injection are associated with developing a substance use disorder more quickly than taking drugs orally or by insufflation (e.g., snorting).

In addition, injecting drugs is also associated with higher rates of infectious diseases and overdose. To better understand how route of drug administration impacts the brain's response to the drug, researchers conducted a double-blind, randomized, counterbalanced clinical trial using simultaneous PET/fMRI imaging.

Part 1

Comment by Dr. Krishna Kumari Challa on November 8, 2023 at 10:08am

Contraceptive Pills Have a strange Effect on The Fear-Promoting Area of The Brain

Scientists have found a possible link between using oral contraceptives and changes in parts of the brain that process fear. The findings may help explain fear-related mechanisms that disproportionately affect women. Hormonal changes during a menstrual cycle are currently understood to affect the fear circuitry in the brain. So researchers looked into the effects of combined oral contraceptive (COC) use to learn more about the relationship between sex hormones our bodies make naturally and synthetic versions of those hormones. This effect appeared to be reversible. A comparison with those who stopped using contraceptives or those who had never used contraceptives indicated this physiological change didn't seem to be lasting. To be clear, these are just associations, and there are no known negative effects linked to the change in size of certain brain regions. But the authors think it could be worth exploring further. This part of the prefrontal cortex is thought to sustain emotion regulation, such as decreasing fear signals in the context of a safe situation. The result may represent a mechanism by which combined OCs could impair emotion regulation in women. Researchers found levels of both natural and synthetic sex hormones were linked to changes in the size and thickness of the vmPFC compared to the same anatomy in men. However, only women who were currently using oral contraceptives had a thinner vmPFC than that in men. The researchers also found the structure in a fear-promoting brain region – the dorsal anterior cingulate cortex (dACC) – varied between men and women. This was noticeable regardless of COC use, emphasizing one way naturally-produced sex hormones can influence brain structure. Given the results that men have smaller dACC volume than women and thicker vmPFC than COC users, these findings may represent structural vulnerabilities to psychopathologies that predominantly affect women.

https://www.frontiersin.org/articles/10.3389/fendo.2023.1228504/full

Comment by Dr. Krishna Kumari Challa on November 8, 2023 at 8:54am

The cell's 'read–write' mechanism: Researchers uncover how instructions for gene expression are relayed

The "read–write" mechanism by which cells replicate and use chemical instructions for expressing genes has been uncovered by  researchers. The quality and quantity of gene expression correlates not only with instructions by transcription factors but also with chemical modifications to the various histone proteins, which provide a scaffold for DNA in the chromosomes.

Scientists have long argued whether these modifications to histones are the epigenetic cause for activating gene expression. And, if that is the case, how they activate gene expression and are maintained during the process of mitosis, in which a cell divides into two daughter cells.

Researchers now have developed an experimental technology that allowed them to generate histones with acetylations at defined sites. They then monitored how p300/CBP interacts with and acetylates a nucleosome containing these selectively acetylated human histones.

The researchers found that p300/CBP recognizes and binds to specific acetylation marks on the H3–H4 complex. The enzyme then replicates acetylation marks to unacetylated sites of H3–H4, while also transcribing them from H3–H4 to H2B–H2A within the same nucleosome. Since this newly acetylated H2B–H2A complex is more likely to be stripped from the nucleosome, a model emerges in which it finally instructs which genes to be transcribed by the cellular transcription machinery. These results provide an unprecedented glimpse into how p300/CBP inherits acetylation marks to newly divided cells and utilizes those marks epigenetically for gene expression.

Masaki Kikuchi et al, Epigenetic mechanisms to propagate histone acetylation by p300/CBP, Nature Communications (2023). DOI: 10.1038/s41467-023-39735-4

Comment by Dr. Krishna Kumari Challa on November 8, 2023 at 8:32am

How global warming shakes the Earth: Seismic data show ocean waves gaining strength as the planet warms

As oceans waves rise and fall, they apply forces to the sea floor below and generate seismic waves. These seismic waves are so powerful and widespread that they show up as a steady thrum on seismographs, the same instruments used to monitor and study earthquakes.

That wave signal has been getting more intense in recent decades, reflecting increasingly stormy seas and higher ocean swell. In a new study in the journal Nature Communications, researchers tracked that increase around the world over the past four decades. These global data, along with other ocean, satellite and regional seismic studies, show a decadeslong increase in wave energy that coincides with increasing storminess attributed to rising global temperatures.

 Richard C. Aster et al, Increasing ocean wave energy observed in Earth's seismic wavefield since the late 20th century, Nature Communications (2023). DOI: 10.1038/s41467-023-42673-w

Comment by Dr. Krishna Kumari Challa on November 8, 2023 at 8:21am

The story of a teenage boy who swallowed 21 disc magnets

Doctors at Guthrie Healthcare System, in Sayre, Pennsylvania, have documented a case of a teenage boy who swallowed 21 disc magnets. In their paper published in BMJ Case Reports, the medical team describes how they found the magnets, removed them, and cared for the boy afterward.

Prior research and anecdotal evidence by doctors and other medical personnel has shown that swallowing magnets can be harmful. Their magnetic field and caustic properties can lead to damage in the digestive tract.

In this new study, the researchers report that a teenage boy was transferred to their facility from another hospital with metal objects of some kind in his stomach. When asked, the boy told the medical staff at both hospitals that he did not know how the objects could have wound up in this stomach. X-rays and a CT scan showed the presence of multiple metallic items. An initial procedure involved removing three small discs that had become embedded in the stomach wall using forceps and a surgical net. After removal, the doctors determined that the metal objects were small disc magnets. Three more of the magnets had become embedded in the walls of the large intestine—notably, there were also signs that the wound caused by the discs had led to decay of intestinal tissue. Further investigation showed that there were another 15 magnets embedded in various parts of both the large and small intestine, most of which required surgery for removal.

The surgeon noted that some of the magnets had begun to create holes in the intestinal walls. The case study team notes that the dangers of ingesting magnets are well known. Instead of passing harmlessly through the digestive tract, they become embedded in the walls of organs, causing tissue decay.

They also note that that the boy in their case study was lucky in the sense that pain caused by the magnets had brought him to the hospital before any of the magnets had time to burrow all the way through organ walls. Leakage of material from the stomach or intestines into other parts of the body can be deadly due to infection.

Simona Maksimyan et al, Clinical course and management of an unknown multiple-magnet ingestion in a teenage male, BMJ Case Reports (2023). DOI: 10.1136/bcr-2023-256418

Comment by Dr. Krishna Kumari Challa on November 8, 2023 at 8:05am

An implantable wireless cardiac pacemaker

Cardiac pacemakers are battery-dependent, where the pacing leads are prone to introduce valve damage and infection. In addition, complete pacemaker retrieval is necessary for battery replacement. Despite the presence of a wireless bioelectronics device to pace the epicardium, surgeons still need to implant the device via thoracotomy, an invasive surgical procedure in health care that necessitates wound healing.

A research team of scientists in bioengineering, microbiology, and cardiology devised a biocompatible wireless microelectronics device to form a microtubular pacemaker for intravascular implantation and pacing. 

The pacemaker provided effective pacing to restore cardiac contraction from a non-beating heart in a porcine animal model. The microtubular pacemaker paves the way for the minimally-invasive implantation of leadless and battery-free microelectronics for health care and cardiac pace restoration.

Shaolei Wang et al, A self-assembled implantable microtubular pacemaker for wireless cardiac electrotherapy, Science Advances (2023). DOI: 10.1126/sciadv.adj0540

Comment by Dr. Krishna Kumari Challa on November 7, 2023 at 11:41am

Dose response: The basics

Comment by Dr. Krishna Kumari Challa on November 7, 2023 at 11:04am

No appetite for vegetarian diet to help the planet, finds study

Social media users believe reducing and eliminating meat intake is ineffective in addressing climate change and reported low willingness to engage in either action, according to a new study.

This is despite recent global reports revealing the strong links between the animal agricultural industry and greenhouse gas emissions, as well as the idea that what people put on their plate is an important piece in confronting the climate crisis. The study, published in Sustainability, asked more than 700 Facebook account users, between the ages of 18 to 84, about their beliefs on climate change, the impact of meat consumption on the environment and meat intake.

Although past research has shown that animal agriculture contributes significantly to greenhouse gas emissions, the participants believed reducing and eliminating meat intake to be some of the least effective actions against climate change.

This study highlighted an increased awareness that meat-eating has environmental impacts, yet its impact was rated significantly less than other pro-environmental behaviors, such as using public transport, recycling, and renewable energy.

The findings of this study can help shed light on the disconnect between research and public knowledge and subsequently, how to bridge this gap. Sci-com? Yes!

 Ashley Rattenbury et al, Perceptions of the Benefits and Barriers to Vegetarian Diets and the Environmental Impact of Meat-Eating, Sustainability (2023). DOI: 10.3390/su152115522

Comment by Dr. Krishna Kumari Challa on November 7, 2023 at 10:56am

 Animal-to-human diseases could kill 12 times as much by 2050: Study

Certain diseases transmitted from animals to humans could kill 12 times as many people in 2050 than they did in 2020, researchers have claimed.

Epidemics caused by zoonotic diseases—also known as spillovers—could be more frequent in the future due to climate change and deforestation, experts warned.

The team's analysis looked at historic trends for four particular viral pathogens.

These were filoviruses, which include Ebola virus and Marburg virus, SARS Coronavirus 1, Nipah virus, and Machupo virus, which causes Bolivian hemorrhagic fever.

The study did not include COVID-19, which caused the global pandemic in 2020 and is likely to have originated in bats.

It looked at more than 3,150 outbreaks between 1963 and 2019, identifying 75 spillover events in 24 countries.

The database covered epidemics reported by the World Health Organization, outbreaks occurring since 1963 that killed 50 or more people, and historically significant events including the flu pandemics of 1918 and 1957.

The events caused 17,232 deaths, with 15,771 caused by filoviruses and occurring mostly in Africa.

Researchers said epidemics have been increasing by almost 5% every year between 1963 and 2019, with deaths up by 9%.

"If these annual rates of increase continue, we would expect the analyzed pathogens to cause four times the number of spillover events and 12 times the number of deaths in 2050 than in 2020," they added.

Researchers also suggested the figures are likely to be an underestimate due to the strict inclusion criteria for the pathogens in the analysis and the exclusion of COVID-19. They said the evaluation of evidence suggests recent epidemics sparked by zoonotic spillovers "are not an aberration or random cluster" but follow "a multi-decade trend in which spillover-driven epidemics have become both larger and more frequent." The team added that "urgent action is needed to address a large and growing risk to global health" based on historical trends.

Amanda Jean Meadows et al, Historical trends demonstrate a pattern of increasingly frequent and severe spillover events of high-consequence zoonotic viruses, BMJ Global Health (2023). DOI: 10.1136/bmjgh-2023-012026

Comment by Dr. Krishna Kumari Challa on November 7, 2023 at 10:44am

Plastic waste in rivers may carry dangerous microbes

Plastic litter in rivers might be allowing dangerous pathogens to hitch-hike downstream, a new study published recently found.

The research, which focused on one river, found that dumped plastic, wooden sticks and the water itself were a breeding ground  for communities of microorganisms, potentially providing a reservoir for bacteria and viruses known to cause human diseases and antibiotic resistance.

These findings indicate that plastic  in freshwater bodies may contribute to the transport of potential pathogens and antibiotic resistance genes.

This could have indirect but significant implications for human health.

Rivers are the main way plastic enters the world's oceans, channeling anywhere between 3.5 thousand metric tons to 2.41 million metric tons of the manmade material to the sea annually.

When plastic ends up in water its surface is overrun within minutes by nearby microbes. The researchers submerged samples for a week in the River Sowe in Warwickshire and West Midlands England, downstream from a wastewater treatment plant. They found significant differences in the microbe communities depending on the material sampled.

Vinko Zadjelovic, Microbial hitchhikers harbouring antimicrobial‑resistance genes in the riverine plastisphere, Microbiome (2023). DOI: 10.1186/s40168-023-01662-3. www.biomedcentral.com/articles … 6/s40168-023-01662-3

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