Comment

Comment by Dr. Krishna Kumari Challa on November 18, 2015 at 9:48am

Scientists at the Children’s Medical Center Research Institute at UT Southwestern (CRI) have determined how the body responds during times of emergency when it needs more blood cells. In a study published in Nature, researchers report that when tissue damage occurs, in times of excessive bleeding, or during pregnancy, a secondary, emergency blood-formation system is activated in the spleen.

“Hematopoietic, or blood-forming, stem cells reside mainly in the bone marrow, and most newblood cell formation occurs within the bone marrow under normal circumstances. But when there is hematopoietic stress, blood cell formation expands to thespleen,” said Dr. Sean Morrison, CRI Director and Mary McDermott Cook Chair in Pediatric Genetics at UT Southwestern Medical Center. “Blood-forming stem cells migrate from the bone marrow to the spleen, which becomes a hematopoietic organ where blood formation then occurs.”

Normally, there are very few blood-forming stem cells in the spleen. But the cells that create the supporting environment for these stem cells are present in the spleen, ready to respond during times of hematopoietic stress and to receive an influx of blood-forming stem cells from the bone marrow.

In characterizing the microenvironment, or niche, which supports blood formation in the spleen, the CRI research team used mouse models to examine the expression patterns of two known niche cell factors, stem cell factor (SCF) and CXCL12. The researchers found that the blood-forming microenvironment in the spleen is found near sinusoidal blood vessels and is created by endothelialcells and perivascular stromal cells – just like the microenvironment in the bone marrow.

“Under emergency conditions, the endothelial cells and perivascular stromal cells that reside in the spleen are induced to proliferate, so they can sustain all the new blood-forming stem cells that migrate into the spleen,” said Dr. Morrison, who is also a CPRIT Scholar in Cancer Research and a Howard Hughes Medical Institute Investigator. “We determined that this process in the spleen is physiologically important for responding to hematopoietic stress; without it, the mice we studied could not maintain normal blood cell counts during pregnancy or quickly regenerate blood cell counts after bleeding or chemotherapy.”

Based on this new information about the spleen’s emergency backup role for blood cell formation, therapeutic interventions could be developed in the future to enhance blood formation following chemotherapy or bone marrow transplantation and thus accelerate the recovery of blood cell counts.

Comment by Dr. Krishna Kumari Challa on November 17, 2015 at 11:41am

Special eye drops raise the hopes for nearsightedness cure
In a five-year clinical trial conducted in Singapore, drops of a drug called atropine seemed to slow the progression of nearsightedness in children. Intriguingly, researchers found that a lower dose of the drug was more effective than higher dosages, in addition to risking fewer side effects. The research was presented Nov. 16, 2015 at the annual meeting of the American Academy of Ophthalmology in Las Vegas and will appear in the February 2016 edition of the journal Ophthalmology.
In high myopia — where the eyeball stretches and becomes too long — isn’t just an inconvenience: It raises the raises the risk of other, more serious eye conditions, such as retinal detachment, macular degeneration, premature cataracts and glaucoma. So the scientists have been trying to find out if there’s any way to reduce the progression of myopia.
tropine drops are approved for use in the United States at a higher concentration than that used in the study. The drops (which are currently used to treat lazy eye in children) can cause light sensitivity and blurry vision up close at higher doses, so researchers set out to determine whether a smaller dose could still be effective without producing side effects. And it did!

Comment by Dr. Krishna Kumari Challa on November 17, 2015 at 6:07am

For the first time scientists correctly predicted the trajectory of space junk
WT1190F, which burned up in Earth's atmosphere Friday, November 13 off the coast of Sri Lanka, as imaged by scientists measuring the re-entry from an airplane. Measuring 3 to 6 feet, the junk was believed to be man-made spacecraft that could have gone off course and turned into space junk orbiting the earth before it entered the atmosphere. In 2013, WT1190F was initially observed by the University of Arizona's Catalina Sky Survey. This event is also an ideal opportunity to test the readiness of space agencies for a possible atmospheric entry and even strong impacts in the future that involve the asteroids and comets which is the highly similar to this WT1190F event. This is the first time that experts have calculated the exact time and location a piece of space junk will collide with Earth. The object's mass was not substantial enough to present a risk to the area, especially given its trajectory into the Indian Ocean. "A piece of a solar panel, for instance, would behave differently than a booster tank", Lowell Observatory planetary astronomer Nick Moskovitz said in a statement before the object's re-entry. The scientists who orchestrated a rapid response to the recently discovered object declared their effort to be a smashing success. NASA scientists were able to forecast the accurate date and time for the re-entry of the space debris. A team from the worldwide Astronomy Center and the UAE Space Agency may be the only people to have seen its final moments in real time. Astronomers had speculated it could be a spent Apollo rocket stage from 1960's or part of a more recent lunar mission. According to EarthSky.org, it was the "first-ever precisely predicted fall of space debris".

Comment by Dr. Krishna Kumari Challa on November 16, 2015 at 8:21am

--

Comment by Dr. Krishna Kumari Challa on November 14, 2015 at 9:28am

The human brain facts:
The human brain has 86 billion neurons in all: 69 billion in the cerebellum, a dense lump at the back of the brain that helps orchestrate basic bodily functions and movement; 16 billion in the cerebral cortex, the brain’s thick corona and the seat of our most sophisticated mental talents, such as self-awareness, language, problem solving and abstract thought; and 1 billion in the brain stem and its extensions into the core of the brain.
The human brain is also unique in its unsurpassed gluttony. Although it makes up only 2 percent of body weight, the human brain consumes a whopping 20 percent of the body’s total energy at rest.

Human brain evolution likely required a metabolic trade-off. In order for the brain to grow, other organs, namely the gut, had to shrink, and energy that would typically have gone to the latter was redirected to the former. For evidence, they pointed to data showing that primates with larger brains have smaller intestines. The invention of cooking was crucial to human brain evolution. Soft, cooked foods are much easier to digest than tough raw ones, yielding more calories for less gastrointestinal work. Perhaps, then, learning to cook permitted a bloating of the human brain at the expense of the gut. Other researchers have proposed that similar trade-offs might have occurred between brain and muscle, given how much stronger chimps are than humans.

Again and again, researchers have cited the evolutionary surge in human brain size as the key reason for our exceptionally high degree of intelligence compared to other animals. Yes, a large brain packed with neurons is essential to what we consider high intelligence.

Comment by Dr. Krishna Kumari Challa on November 13, 2015 at 9:28am

Truth here and now...1

Q: What Really Causes Autism?

A: Not vaccines! No. A range of mutations—common, rare, inherited and spontaneous—in more than 70 different genes are now linked to the disorder.

Here are the latest findings and ideas from scientists about what might really cause this mysterious condition.

Genetics

There is strong evidence that changes in our genes contribute to autism.

For one thing, the disorder is highly heritable. Families that have one child with autism have a 1 in 20 chance of having a second child with autism.

Research has also shown that the genetic changes that contribute to autism don't have to be inherited — they may also arise spontaneously.

In total, scientists have identified about 20 genes that may be involved in autism. Children with a genetic mutation on chromosome 17 were 14 times more likely to develop autism than those without the mutation.

Pesticides

Exposure to pesticides has also been linked to autism. Some studies have found that pesticides may interfere with genes involved in the central nervous system. Scientists think that chemicals in pesticides may adversely affect those who are genetically predisposed to autism.

Pharmaceuticals

Babies that have been exposed to certain pharmaceuticals in the womb, including valproic acid and thalidomide, have been found to have a higher risk of autism.

Thalidomide is a drug that was first used in the 1950s to treat morning sickness, anxiety and insomnia. The drug was withdrawn from the market after it was linked with birth defects, but is currently prescribed for a severe skin disorder and as a treatment for cancer. Valproic acid is a medication prescribed for seizures, mood disorders and bipolar disorder. 

Parental age

As parents grow older, they have a higher risk of having children with autism, according to some studies. A study published last February found that women who are 40 years old have a 50 percent greater risk of having a child with autism than women who are between 20 and 29 years old.

Researchers aren't sure why parental age may influence autism risk, but it might be related to genetic mutations that occur in the sperm or the egg as parents grow older.

The development of the brain

Particular areas of the brain, including the cerebral cortex and the cerebellum, have been implicated in autism. These brain areas are thought to be responsible for concentration, movement and mood regulation.

Irregularities in the levels of neurotransmitters, such as dopamine and serotonin, have also been tied to autism. Problems regulating dopamine can lead to problems with concentration and movement disabilities, while troubles controlling serotonin levels can result in mood problems.

Comment by Dr. Krishna Kumari Challa on November 13, 2015 at 9:13am

Turning the tide ... using the worst thing happened to your work to do your best... How scientists use out of control satellites to test a theory...

Two satellites that were accidentally launched into the wrong orbit will be repurposed to make the most stringent test to date of a prediction made by Albert Einstein’s general theory of relativity—that clocks run more slowly the closer they are to heavy objects.

The satellites, operated by the European Space Agency (ESA), were mislaunched last year by a Russian Soyuz rocket that put them into elliptical, rather than circular, orbits. This left them unfit for their intended use as part of a European global-navigation system called Galileo.

But the two crafts still have atomic clocks on board. According to general relativity, the clocks' 'ticking' should slow down as the satellites move closer to Earth in their wonky orbits, because the heavy planet’s gravity bends the fabric of space-time. The clocks should then speed up as the crafts recede.

On November 9, ESA announced that teams at Germany's Center of Applied Space Technology and Microgravity (ZARM) in Bremen and the department of Time–Space Reference Systems at the Paris Observatory will now track this rise and fall. By comparing the speed of the clocks’ ticking with the crafts’ known altitudes—pinpointed within a few centimetres by monitoring stations on the ground, which bounce lasers off the satellites—the teams can test the accuracy of Einstein's theory.

http://www.nature.com/news/wayward-satellites-repurposed-to-test-ge...

Comment by Dr. Krishna Kumari Challa on November 13, 2015 at 9:05am

Comment by Dr. Krishna Kumari Challa on November 12, 2015 at 11:58am

Scientists breach brain barrier to treat sick patient
For the first time, doctors have breached the human brain's protective layer to deliver cancer-fighting drugs.

The Canadian team used tiny gas-filled bubbles, injected into the bloodstream of a patient, to punch temporary holes in the blood-brain barrier.

A beam of focused ultrasound waves applied to the skull made the bubbles vibrate and push their way through, along with chemotherapy drugs.

Six to 10 more patients will undergo the same procedure as part of a trial.

Experts said the experimental technique used at Sunnybrook Health Sciences Centre was exciting because it meant doctors might be able to give cancer patients potent drugs that otherwise would not work.
The same non-invasive method could also be used for other brain diseases, such as dementia and Parkinson's.
Blood-brain barrier

The blood-brain barrier keeps pathogens and toxins away from the central nervous system. But this tightly packed layer of cells, which separates the brain from its blood vessels, can be a hindrance if you want to deliver drugs into the brain.

The Sunnybrook team temporarily ripped holes in the barrier to allow chemotherapy a safe passage through.
The patient was given an intravenous infusion of chemotherapy followed by a small dose of the micro-bubbles that would punch a way through once they reached the target area of the brain and the ultrasound beam was switched on.

Brain scans suggest the treatment went to plan, and the researchers will soon examine a small part Ms Hall's tumour (removed surgically the day after the therapy) to confirm how much of the chemotherapy penetrated.
"Opening the blood-brain barrier using focused ultrasound beams has been a goal of researchers for about a decade, with the Toronto group being at its forefront, and it is exciting to see this reaching the clinic at last.

"The use of ultrasound for enhancing the local delivery of drugs to a number of different targets in the body is being investigated by a number of centres around the world, including the UK, and shows particular promise in the field of cancer chemotherapy."

Comment by Dr. Krishna Kumari Challa on November 12, 2015 at 11:33am

Brain Too Can Get Fossilised

Scientists have long maintained that brains do not fossilise but new research has provided the strongest evidence yet that it is possible. In fact, the brains of a set of 520-million-year-old arthropods did just that.

The species, Fuxianhuia protensa, is an extinct arthropod that roamed the seafloor about 520 million years ago. It would have looked something like a very simple shrimp.

“Each of the fossils found at Chengjiang Shales fossil-rich sites in southwest China revealed F protensa’s ancient brain looked a lot like a modern crustacean’s,” said Nicholas Strausfeld, a Regents’ professor in the department of neuroscience at the University of Arizona.

He and his team found that the brains were preserved as flattened carbon films.

This led the research team to a convincing explanation as to how and why neural tissue fossilises.

The only way for an object to be fossilised is for it to be rapidly buried.

Hungry scavengers cannot eat a carcass if the brain is buried faster and as long as the water lacks in oxygen so a buried creature’s tissues escapes being consumed by bacteria as well.

Strausfeld and his collaborators suspect F. protensa was buried by rapid, underwater mudslides a scenario they experimentally recreated by burying sandworms and cockroaches in mud.

According to Strausfeld, the brain withstood the pressure from being rapidly buried under thick mud because the nervous system must have been remarkably dense.

In fact, tissues of nervous systems, including brains, are densest in living arthropods.

In the paper, Strausfeld and Xiaoya Ma from China’s Yunnan University and Gregory Edgecombe from the Natural History Museum in London analysed seven newly discovered fossils of the same species to find, in each, traces of what was undoubtedly a brain.

Strausfeld is now working to elucidate the origin and evolution of brains over half a billion years in the past.

“People, especially scientists, make assumptions. The fun thing about science, actually, is to demolish them,” Strausfeld noted in the paper published in the journal Current Biology.

• ‹ Previous
• 1
• …
• 670
• 671
• 672
• 673
• 674
• …
• 855
• Next ›
• Page