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Comment by Dr. Krishna Kumari Challa on July 8, 2015 at 7:25am

Bivalent separation into univalents precedes age-related meiosis I errors in oocytes

Defective chromosome separation in the egg cells of older women can cause miscarriage and congenital diseases according to scientists
researchers at the RIKEN Center for Developmental Biology in Japan have used a novel imaging technique to pinpoint a significant event that leads to these types of age-related chromosomal errors. Published in Nature Communications, the study shows that as egg cells mature in older women, paired copies of matching chromosomes often separate from each other at the wrong time, leading to early division of chromosomes and their incorrect segregation into mature egg cells. Most cells have two copies of each chromosome—one from each parent. Immature egg cells also begin this way, but are transformed through a process called meiosis into mature egg cells that only have one copy of each chromosome. At the beginning of meiosis each chromosome copies itself and joins with its matching pair to form a group of four chromosomes that swap genetic material. These groups of four chromosomes—called bivalents—then split apart into single pairs, and the cell divides. One part continues as the egg cell and the other part degrades. In the second stage of meiosis, the single pairs of chromosomes—two sister chromatids joined in the middle—separate and the egg cell divides again in the same way, leaving a single mature egg cell with one copy of each chromosome.
They found that chromosomes were always distributed correctly in young egg cells, but that a little less than 10 percent of older cells suffered from segregation errors. Closer examination of the chromosome-tracking data showed that the dominant type of error was predivision of sister chromatids, and not movement of intact chromosome pairs to only one of the new cells. The tracking data also allowed researchers to go back in time and look at what was happening to chromosomes that eventually segregated incorrectly. They found that a large majority of them had been part of bivalents whose connection between paired chromosome copies had become hyperstretched and then snapped earlier in meiosis, leaving single pairs. The researchers then confirmed that the number of singly paired chromosomes—also called univalents—was higher in older mouse and even human egg cells, indicating that age-related segregation errors could be tracked back to increased numbers of prematurely separated chromosome pairs.
http://www.nature.com/ncomms/2015/150701/ncomms8550/full/ncomms8550...

Comment by Dr. Krishna Kumari Challa on July 5, 2015 at 6:50am

Researchers have developed a machine to simulate the effects of Earth’s gravity in space to alleviate the problems of space travel.

Astronauts who spend a long time in the micro-gravity environment of space can experience muscle deteoriation, bone loss and other harmful effects on their body.

But using a special type of centrifuge, researchers say these problems could be minimised - ensuring astronauts on a future mission to Mars, for example, arrive fit and healthy.

The technology was developed by scientists at the Massachusetts Institute of Technology (MIT).

It works around the concept of a centrifuge - a spinning contraption that exerts a force on a human occupant through its rotation.

Rotating at a specific speed will ‘push’ the astronaut back, in effect mimicking the force they would feel from Earth’s gravity.

The research was published in the journal Acta Astronautica.

http://www.sciencedirect.com/science/article/pii/S0094576515001344

Humans experience physiological deconditioning during space missions, primarily attributable to weightlessness. Some of these adverse consequences include bone loss, muscle atrophy, sensory-motor deconditioning, and cardiovascular alteration, which may lead to orthostatic intolerance when astronauts return to Earth. Artificial gravity could provide a comprehensive countermeasure capable of challenging all the physiological systems at once, particularly if combined with exercise, thereby maintaining overall health during extended exposure to weightlessness. A new Compact Radius Centrifuge (CRC) platform was designed and built on the existing Short Radius Centrifuge (SRC) at the Massachusetts Institute of Technology (MIT). The centrifuge has been constrained to a radius of 1.4 m, the upper radial limit for a centrifuge to fit within an International Space Station (ISS) module without extensive structural alterations. In addition, a cycle ergometer has been added for exercise during centrifugation. The CRC now includes sensors of foot forces, cardiovascular parameters, and leg muscle electromyography. An initial human experiment was conducted on 12 subjects to analyze the effects of different artificial gravity levels (0 g, 1 g, and 1.4 g, measured at the feet) and ergometer exercise intensities (25 W warm-up, 50 W moderate and 100 W vigorous) on the musculoskeletal function as well as motion sickness and comfort. Foot forces were measured during the centrifuge runs, and subjective comfort and motion sickness data were gathered after each session. Preliminary results indicate that ergometer exercise on a centrifuge may be effective in improving musculoskeletal function. The combination is well tolerated and motion sickness is minimal. The MIT CRC is a novel platform for future studies of exercise combined with artificial gravity. This combination may be effective as a countermeasure to space physiological deconditioning.

Comment by Dr. Krishna Kumari Challa on July 3, 2015 at 1:40pm

POPs and Gut Microbiota: Dietary Exposure Alters Ratio of Bacterial Species
Persistent organic pollutants (POPs) have been implicated in myriad human health problems, including cancer, neurologic, immunologic, and reproductive defects, among many other adverse health effects. New lines of research suggest that chronic dietary exposure to POPs may also contribute to obesity and type 2 diabetes. In this issue of EHP, researchers examine how one POP in particular—2,3,7,8 tetrachlorodibenzofuran (TCDF)—affects the composition of the mouse gut microbiome. They report that TCDF exposure alters the gut microbiome in ways that may prove to contribute to obesity and other metabolic diseases.

TCDF binds the aryl hydrocarbon receptor (AHR), which activates a variety of biological responses. Recent studies indicate that keeping the gut in good working order is one of these functions.
http://ehp.niehs.nih.gov/123-a187/

Comment by Dr. Krishna Kumari Challa on July 3, 2015 at 1:27pm

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

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