Comment

Comment by Dr. Krishna Kumari Challa on January 17, 2024 at 6:57am

Energy-starved breast cancer cells consume their surroundings for fuel, research suggests

Breast cancer cells ingest and consume the matrix surrounding them to overcome starvation, according to a new study published January 16 in the open access journal PLOS Biology. The finding elucidates a previously unknown mechanism of cancer cell survival, and may offer a new target for therapy development.

Cells in the breast, including tumor cells, are embedded in a meshwork called the extracellular matrix (ECM). Nutrients are scarce in the ECM, due to limited blood flow, and become even scarcer as tumor cells grow. And yet they continue to grow, leading the authors to investigate how tumor cells supply themselves with the raw materials to support that growth. To do so, they seeded breast adenocarcinoma cells into either collagen (a major component of the ECM) or a commercial matrix preparation, or onto plastic, with or without certain critical amino acids. Without those amino acids, cells on plastic fared poorly compared to those in one or the other matrix. Similar results were seen with other matrix models—the tumor cells were able to overcome the reduction of amino acids when surrounded by matrix. Next, by fluorescently labeling the collagen and watching its journey through the cell, the authors showed that the cells took up ECM and broke it down in digestive compartments called lysosomes; when the ECM was chemically treated to cross-link its components, the cells were unable to ingest it. Further investigation indicated that uptake was through an ingestion process called macropinocytosis, in which the cell engulfs large quantities of extracellular material. What were the tumor cells after? Analysis of their metabolome indicated that procurement and breakdown of two amino acids, tyrosine and phenylalanine, dominated the metabolic changes in response to starvation. The authors noted that these two can serve as the raw material for energy production through the mitochondrial tricarboxylic acid (Krebs) cycle. When they knocked down HPDL, a central enzyme in the pathway from phenylalanine to the TCA, cell growth was significantly impaired. Blocking or reducing expression of HPDL, or the macropinocytosis promoter PAK1, reduced the ability of tumor cells to migrate and to invade surrounding tissue. These results indicate that breast cancer cells take advantage of nutrients in the extracellular matrix in times of nutrient starvation, and that this process depends on both macropinocytosis and metabolic conversion of key amino acids to energy-releasing substrates.

Nazemi M, Yanes B, Martinez ML, Walker HJ, Pham K, Collins MO, et al. (2024) The extracellular matrix supports breast cancer cell growth under amino acid starvation by promoting tyrosine catabolism. PLoS Biology (2024). DOI: 10.1371/journal.pbio.3002406

Comment by Dr. Krishna Kumari Challa on January 17, 2024 at 6:52am

Amnesia caused by head injury reversed in early mouse study

A mouse study designed to shed light on memory loss in people who experience repeated head impacts, such as athletes, suggests the condition could potentially be reversed. The research in mice finds that amnesia and poor memory following head injury are due to inadequate reactivation of neurons involved in forming memories.

The study, conducted by researchers is reported January 16, 2024, in The Journal of Neuroscience.

Importantly for diagnostic and treatment purposes, the researchers found that the memory loss attributed to head injury was not a permanent pathological event driven by a neurodegenerative disease. Indeed, the researchers could reverse the amnesia to allow the mice to recall the lost memory, potentially allowing cognitive impairment caused by head impact to be clinically reversed.
The  investigators had previously found that the brain adapts to repeated head impacts by changing the way the synapses in the brain operate. This can cause trouble in forming new memories and remembering existing memories. In their new study, investigators were able to trigger mice to remember memories that had been forgotten due to head impacts.

 Amnesia after repeated head impact is caused by impaired synaptic plasticity in the memory engram, The Journal of Neuroscience (2024).

Comment by Dr. Krishna Kumari Challa on January 17, 2024 at 6:42am

UK-wide study reveals harm done by people not getting COVID jabs

More than 7,000 people were hospitalized or died from COVID-19 in the UK during the summer of 2022 because they had not received the recommended number of vaccine doses, according to a study released Tuesday that was the first to cover Britain's entire population.

The researchers said the "landmark" population-wide study showed how important it is for people to keep getting booster jabs as COVID continues to pose a major health threat. More than 90 percent of the UK's adult population were vaccinated during the earlier stages of the pandemic. However, between June to September 2022, after the pandemic's emergency phase was declared over and attention turned elsewhere, around 44 percent of Britons were under-vaccinated, the researchers said. Using individual health data from the National Health Service (NHS) as well as modeling, the researchers estimated that there would have been 7,180 fewer hospitalizations or deaths if everyone had been up to date with their shots. That means that nearly 20 percent of the 40,000 COVID hospitalizations or deaths over the summer could have been avoided if Britons were fully vaccinated.

Undervaccination and severe COVID-19 outcomes: meta-analysis of national cohort studies in England, Northern Ireland, Scotland, and Wales, The Lancet (2024). DOI: 10.1016/S0140-6736(23)02467-4 , www.thelancet.com/journals/lan … (23)02467-4/fulltext

Comment by Dr. Krishna Kumari Challa on January 16, 2024 at 3:42pm

"We have finally unveiled the intricate story of when, where, and how plants respond to airborne 'warning messages' from their threatened neighbors," says Masatsugu Toyota, a molecular biologist at Saitama University in Japan and senior author of the study.

"This ethereal communication network, hidden from our view, plays a pivotal role in safeguarding neighboring plants from imminent threats in a timely manner."

The study has been published in Nature Communications.

https://www.sciencealert.com/scientists-film-plant-talking-to-its-n...

Part 4

**

Comment by Dr. Krishna Kumari Challa on January 16, 2024 at 3:41pm

It wasn't a natural set-up; the compounds were concentrated in a plastic bottle and pumped onto the recipient plant at a constant rate, but this allowed the researchers to analyze what compounds were in the pungent mix.

As you can see in the video above, the undamaged plants received the messages of their injured neighbors loud and clear, responding with bursts of calcium signaling that rippled across their outstretched leaves.

Analyzing the airborne compounds, the researchers found that two compounds called Z-3-HAL and E-2-HAL induced calcium signals in Arabidopsis.

They also identified which cells are the first to respond to the danger cues by engineering Arabidopsis plants with fluorescent sensors exclusively in guard, mesophyll, or epidermal cells.

Guard cells are bean-shaped cells on plant surfaces that form stomata, small pores that open up to the atmosphere when plants 'breathe' in CO2. Mesophyll cells are the inner tissue of leaves, and epidermal cells are the outermost layer or skin of plant leaves.

When Arabidopsis plants were exposed to Z-3-HAL, guard cells generated calcium signals within a minute or so, after which mesophyll cells picked up the message.

What's more, pre-treating plants with a phytohormone that shuts stomata significantly reduced calcium signaling, suggesting stomata act as the 'nostrils' of the plant.
part 3

Comment by Dr. Krishna Kumari Challa on January 16, 2024 at 3:40pm

Caterpillars (Spodoptera litura) were set upon leaves cut from tomato plants and Arabidopsis thaliana, a common weed in the mustard family, and the researchers imaged the responses of a second, intact, insect-free Arabidopsis plant to those danger cues.

These plants weren't any ordinary weeds: they had been genetically altered so their cells contained a biosensor that fluoresced green when an influx of calcium ions was detected. Calcium signaling is something human cells use to communicate too.

The team used a similar technique to measure calcium signals in a study last year of fluorescent Mimosa pudica plants, which quickly move their leaves in response to touch, to avoid predators.

This time, the team visualized how plants responded to being bathed in volatile compounds, which plants release within seconds of wounding.

Part 2

Comment by Dr. Krishna Kumari Challa on January 16, 2024 at 3:39pm

Scientists Film Plant 'Talking' to Its Neighbour

Imperceptible to us, plants are surrounded by a fine mist of airborne compounds that they use to communicate and protect themselves. Kind of like smells, these compounds repel hungry herbivores and warn neighboring plants of incoming assailants.

Scientists have known about these plant defenses since the 1980s, detecting them in over 80 plant species since then. Now, a team of Japanese researchers has deployed real-time imaging techniques to reveal how plants receive and respond to these aerial alarms.

This was a big gap in our understanding of plant chatter: we knew how plants send messages, but not how they receive them.

In this study, Yuri Aratani and Takuya Uemura, molecular biologists at Saitama University in Japan, and colleagues rigged up a pump to transfer compounds emitted by injured and insect-riddled plants onto their undamaged neighbors, and a fluorescence microscope to watch what happened.

Comment by Dr. Krishna Kumari Challa on January 16, 2024 at 2:44pm

Joining the ranks of existing polydrugs
Kush is another example of polydrug mixtures of which forensic scientists are becoming increasingly aware. Another tobacco and cannabis-based drug, nyaope, otherwise known as whoonga, is found in South Africa.

This time the tobacco and cannabis are mixed with heroin and antiretroviral drugs used to treat Aids, some of which are hallucinogenic.

A further polydrug, "white pipe", a mixture of methaqualone (Mandrax), cannabis and tobacco, is smoked in southern Africa.

These drugs are inexpensive and provide an escape from unemployment, the drudgery of poverty, sexual and physical abuse, and the effect, in some cases, especially in west Africa, from having been a child soldier.
So what can be done about these drugs? The effectiveness of legislation alone is questionable, and many of those who attend the very limited rehabilitation centres return to drug use.

Perhaps what is required is an integrated forensic healthcare system where legislative control is backed up by properly resourced rehabilitation centres coupled with a public health and employment programme. What changes are made in response to this epidemic remains to be seen.

Michael Cole, Professor of Forensic Science, Anglia Ruskin University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Part 3

**

Comment by Dr. Krishna Kumari Challa on January 16, 2024 at 2:43pm

Where is the drug found?
The drug is reported in both Guinea and Liberia, which share porous land borders with Sierra Leone, making drug trafficking easy.

Kush costs around five leones (20 UK pence) per joint, which may be used by two or three people, with up to 40 joints being consumed in a day.

This represents a massive spend on drugs and illustrates the addictive nature of the mixture, in a country where the annual income per capita is around £500.

The effects of the drug vary and depend on the user and the drug content. Cannabis causes a wide variety of effects, which include euphoria, relaxation and an altered state of consciousness.
Fentanyl, an extremely potent opioid, produces euphoria and confusion and causes sleepiness among a wide range of other side-effects.

Similarly, tramadol, which is also an opioid but less potent than fentanyl (100mg tramadol has the same effect as 10mg morphine) results in users becoming sleepy and "spaced out" – disconnected from things happening around them.

The danger of the drug is twofold: the risk of self-injury to the drug taker and the highly addictive nature of the drug itself. A further problem is the need to finance the next dose, often achieved through prostitution or criminal activity
Part 2

Comment by Dr. Krishna Kumari Challa on January 16, 2024 at 2:42pm

Deadly 'Zombie Drug' Believed to Contain Human Bones Wreaks Havoc in West Africa

A new drug called kush is wreaking havoc in west Africa, particularly in Sierra Leone where it is estimated to kill around a dozen people each week and hospitalise thousands.
The drug, taken mostly by men aged 18 to 25, causes people to fall asleep while walking, to fall over, to bang their heads against hard surfaces and to walk into moving traffic.
Kush should not be confused with the drug of the same name found in the US, which is a mixture of "an ever-changing host of chemicals" sprayed on plant matter and smoked.

Kush in Sierra Leone is quite different; it is a mixture of cannabis, fentanyl, tramadol, formaldehyde and – according to some – ground down human bones.

It is mixed by local criminal gangs, but the constituent drugs have international sources, facilitated no doubt by the internet and digital communications.

While cannabis is widely grown in Sierra Leone, the fentanyl is thought to originate in clandestine laboratories in China where the drug is manufactured illegally and shipped to west Africa.

Tramadol has a similar source, namely illegal laboratories across Asia. Formaldehyde, which can cause hallucinations, is also reported in this mixture.

As for ground human bones, there is no definitive answer about whether or not they occur in the drug, where such bones would come from, or why they might be incorporated into the drug.

Some people say that grave robbers provide the bones, but there is no direct evidence of this.
But why would bones be incorporated into the drug? Some suggest that the sulphur content of the bones causes a high. Another reason might be the drug content of the bones themselves, if the deceased was a fentanyl or tramadol user.

However, both are unlikely. Sulphur levels in bones are not high. Smoking sulphur would result in highly toxic sulphur dioxide being produced and inhaled. Any drug content in bones is orders of magnitude less than that required to cause a physiological effect.
Part 1

• ‹ Previous
• 1
• …
• 207
• 208
• 209
• 210
• 211
• …
• 1003
• Next ›
• Page