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Comment by Dr. Krishna Kumari Challa on July 2, 2015 at 11:58am

Sex divide seen in mechanism that produces persistent pain

Research showing that male and female mice regulate pain sensitivity differently raises questions about gender balance in experimental design.

http://www.nature.com/news/sex-divide-seen-in-mechanism-that-produc...

Comment by Dr. Krishna Kumari Challa on July 2, 2015 at 11:54am

The children of genetically-unrelated parents are more likely than those with similar genes to be taller and more intelligent according to the biggest study yet of human genetic diversity in an age when more people than ever are marrying people from different parts of the world.

Scientists found that height and general intelligence were two traits that appear to be increasing as a result of the mixing of DNA between genetically-diverse parents who on average share fewer genes than more closely related individuals.

However, the researchers also found that the increasing genetic diversity of the human population appeared to have little or no effect on a range of other medical traits, such as blood pressure, which could affect peoples’ health over their lifetimes.

Ever since Charles Darwin, scientists have argued over the effects of “inbreeding” between close relatives such as first cousins, but there have been few studies to look into the positive benefits of “outbreeding” between more distantly-related parents with widely different genetic backgrounds.

The latest research, published in the journal Nature, analysed more than 100 separate studies carried out around the world involving some 350,000 people living in both rural and urban environments.

Comment by Dr. Krishna Kumari Challa on June 9, 2015 at 8:30am

Polygenic risk scores for schizophrenia and bipolar disorder predict creativity

http://www.nature.com/neuro/journal/vaop/ncurrent/full/nn.4040.html

Results imply creative people are 25% more likely to carry genes that raise risk of bipolar disorder and schizophrenia.

In a large study published on Monday, scientists in Iceland report that genetic factors that raise the risk of bipolar disorder and schizophrenia are found more often in people in creative professions. Painters, musicians, writers and dancers were, on average, 25% more likely to carry the gene variants than professions the scientists judged to be less creative, among which were farmers, manual labourers and salespeople.

“To be creative, you have to think differently. And when we are different, we have a tendency to be labelled strange, crazy and even insane.”

The scientists drew on genetic and medical information from 86,000 Icelanders to find genetic variants that doubled the average risk of schizophrenia, and raised the risk of bipolar disorder by more than a third. When they looked at how common these variants were in members of national arts societies, they found a 17% increase compared with non-members. For 1% of the population, genetic factors, life experiences and other influences can culminate in problems, and a diagnosis of mental illness.

This study found only a weak link between the genetic variants for mental illness and creativity.

( Some scientists argue that this evidence is flimsy. Remember we cautioned you!)

 Albert Rothenberg, professor of psychiatry at Harvard University is not convinced. He believes that there is no good evidence for a link between mental illness and creativity. “It’s the romantic notion of the 19th century, that the artist is the struggler, aberrant from society, and wrestling with inner demons,” he said. “But take Van Gogh. He just happened to be mentally ill as well as creative. For me, the reverse is more interesting: creative people are generally not mentally ill, but they use thought processes that are of course creative and different.”

In 2014, Rothernberg published a book, “Flight of Wonder: an investigation of scientific creativity”, in which he interviewed 45 science Nobel laureates about their creative strategies. He found no evidence of mental illness in any of them. He suspects that studies which find links between creativity and mental illness might be picking up on something rather different.

“The problem is that the criteria for being creative is never anything very creative. Belonging to an artistic society, or working in art or literature, does not prove a person is creative. But the fact is that many people who have mental illness do try to work in jobs that have to do with art and literature, not because they are good at it, but because they’re attracted to it. And that can skew the data,” he said. “Nearly all mental hospitals use art therapy, and so when patients come out, many are attracted to artistic positions and artistic pursuits.”

Comment by Dr. Krishna Kumari Challa on June 9, 2015 at 7:59am

Comment by Dr. Krishna Kumari Challa on June 6, 2015 at 7:40am

Comment by Dr. Krishna Kumari Challa on June 6, 2015 at 7:32am

There's a lesser-known biometric,that might be a bit harder to counterfeit: brainwaves. "In the biometric textbook table of contents, often the brain biometrics were listed as ‘Esoteric Biometrics.
Each person has slightly different so-called "brainprints." Different enough that computers were able to uniquely identify the study volunteers by their brainwaves 94 percent of the time. That effect held up when the subjects were retested six months later. The results are in the journal Neurocomputing. [Blair C. Armstrong et al, Brainprint: Assessing the uniqueness, collectability, and permanence of a novel method for ERP biometrics]
Brainprint: Assessing the uniqueness, collectability, and permanence of a novel method for ERP biometrics
http://www.sciencedirect.com/science/article/pii/S0925231215004725

Comment by Dr. Krishna Kumari Challa on June 6, 2015 at 7:25am

Delirium is a type of sudden-onset brain dysfunction characterised by cognitive problems such as inattention and fluctuation in symptoms.
Reasons for development of delirium in the ICU patients include medications such as benzodiazepine and other sedatives. These are commonly given to patients to help them stay calm and sleep but can paradoxically cause disorientation and confusion in some patients.
the goal should be reduction or elimination of such medications, especially in more vulnerable patients such as the elderly and dementia patients, and to establish better night-time routines in hospitals such that patients are allowed to sleep with minimal interruptions. However, there are other causes of delirium, which might be more difficult to reduce. Illnesses such as severe pneumonia can cause secondary inflammation in the brain. It has also been suggested that changes in blood flow to the brain can result in delirium. The current study indicated that long-term risk of cognitive decline is increased by 20-30% in the patients who experience delirium in the ICU.
Development of delirium approximately doubles the risk of death in critically ill patients in hospital intensive care units, according to the results of a new study in the British Medical Journal (BMJ). The systematic review and meta-analysis study was carried out by a team of researchers based in Brazil and the United States, led by Johns Hopkins Medicine researchers.
Outcome of delirium in critically ill patients: systematic review and meta-analysis
http://www.bmj.com/content/350/bmj.h2538

Comment by Dr. Krishna Kumari Challa on June 6, 2015 at 7:19am

In a new study from researchers in the University of Tel Aviv, a strategy is described for using phages to deliver a nuclease that targets antibiotic resistance genes in bacteria. Phages, which are viruses that infect bacteria, are the natural enemies of bacteria. This strategy renders these resistant bacteria susceptible to antibiotics and also prevents transfer of resistance from one strain to another. The study was led by Prof Udi Qimron and is published in the journal PNAS.

The spread of antibiotic resistance among pathogens is a worldwide public health crisis, prompting the World Health Organisation, at its annual assembly in Geneva last week, to approve an ambitious plan to slow it down. The research described in the PNAS paper is a promising step in the right direction. According to the study’s authors, applying their phage-based system to hospital surfaces and to the hands of medical personnel could help us to fight back against untreatable, often lethal bacterial infections. Prof Qimron explained: "Since there are only a few pathogens in hospitals that cause most of the antibiotic-resistance infections, we wish to specifically design appropriate sensitization treatments for each one of them. We will have to choose suitable combinations of DNA-delivering phages that would deliver the DNA into pathogens, and the suitable combination of 'killing' phages that could select the re-sensitized pathogens."

In this system, phages were programmed to deliver a programmable DNA nuclease, which is called clustered regularly interspaced short palindromic repeats (CRISPR)–CRISPR-associated (Cas), into the genome of antibiotic-resistant bacteria. This shot to the heart of the resistant bacteria resulted in reversal of the antibiotic resistance, rendering them sensitive to antibiotics, while protecting the bacteria that were already sensitive to antibiotics.

In essence this system is therefore selective for antibiotic-sensitive bacteria, thus applying the opposite selective pressure to antibiotics themselves. Prof Qimron explained: "Antibiotic-resistant pathogens constitute an increasing threat because antibiotics are designed to select resistant pathogens over sensitive ones. The injected DNA does two things: It eliminates the genes that cause resistance to antibiotics, and it confers protection against lethal phages. We managed to devise a way to restore antibiotic sensitivity to drug-resistant bacteria, and also prevent the transfer of genes that create that resistance among bacteria.” The CRISPR-Cas system also destroyed the lytic phages themselves. Prof Qimron said: "We believe that this strategy, in addition to disinfection, could significantly render infections once again treatable by antibiotics."
http://www.pnas.org/content/early/2015/05/14/1500107112

Comment by Dr. Krishna Kumari Challa on June 6, 2015 at 7:18am

When nose acts like brain...

Hormone ‘Erases’ Male Smell for Female Mice

In a new study, scientists at The Scripps Research Institute (TSRI) have found that state-specific odor “blindness” exists in female mice. Their research shows that female mice cannot sense the odor of male mice when they are in diestrus, the period of sexual inactivity during the reproductive cycle.

The researchers discovered that during this period, receptors in the female mouse’s nose actually block the signals from male odor molecules from ever reaching the brain. This lack of sensation directly affects mouse behavior.

“The nose was making decisions and acting like an extension of the brain.”

These findings, which point to new avenues for studying senses and behavior, were published June 4, 2015, in the journal Cell.

The new study started with an observation well-known in the field: While female mice are attracted to male mice during estrus—when they are receptive to breeding—female mice are indifferent to, and even aggressive toward, male mice during diestrus.

Researchers have long suspected that this change in behavior is related to hormonal changes in the brain during the reproductive cycle. Hormones produced in the ovaries during estrus and diestrus are known to activate specific neurons in the female brain. Stowers and her team aimed to study those neurons further. Before they investigated the brain, however, the researchers first wanted to rule out any activity in the nose that might be affecting the odor cues.

The researchers investigated a subset of neurons in a special organ in the nose called the vomeronasal organ (VNO), which detects male odors.

Using a technique called calcium imaging, the researchers discovered that these neurons don’t always detect male odors. The neurons have a “gating” mechanism and fail to activate in the presence of a hormone called progesterone, which is produced in the ovaries during diestrus. They found that progesterone acts through receptors on the surface of these sensory neurons, stopping them from transmitting the male odor smell to the brain.

Without these neurons activating, the female mouse can’t perceive male odors that promote behavior. This means ­the choice to perform behavior is being regulated in the nose itself, without thought from the brain.

What made the findings even stranger was the fact that no progesterone receptors had ever been detected in VNO neurons before. This prompted the researchers to dig further to figure out what was going on.

First, the researchers wanted to see if progesterone was disabling VNO function altogether.

To test this, the researchers checked the VNO response to predator cues—in this case, the scent of cat urine, which mice instinctually avoid. The researchers found that the subset of VNO neurons that usually respond to cat urine continued to respond normally, even in the presence of progesterone.

This showed that the ability female mice to smell in general was indeed still active during periods of diestrus.

Next, the researchers took a closer look at the signaling process. They discovered that when progesterone is detected by VNO neurons, it changes a signaling molecule that would normally relay the odor to the brain. Because only male odor-specific VNO neurons are susceptible to this change, they are the only ones that switch off in the presence of progesterone.

The reason for this male odor “blindness” is still unclear. Stowers said there is no evidence for the notion that male odors distract females from finding food or shelter. After all, female mice can smell male mice during estrus, and they still survive.

http://www.cell.com/cell/abstract/S0092-8674%2815%2900555-3

Comment by Dr. Krishna Kumari Challa on June 6, 2015 at 6:37am

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