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Comment by Dr. Krishna Kumari Challa on March 12, 2015 at 8:44am

Comment by Dr. Krishna Kumari Challa on March 11, 2015 at 9:55am

Irisin – a myth rather than an exercise-inducible myokine

The myth of Irisin - the exercise hormone:

The discovery of the "exercise hormone" irisin three years ago and more than 170 related papers about it since have been called into question by recent research showing they were based on flawed testing kits.

Previous studies suggested that the hormone irisin -- named for the Greek messenger goddess Iris -- travels from muscle to fat tissue after exercise to tell fat cells to start burning energy instead of storing it. The finding ignited hope and press coverage that irisin could hold the key to fighting diabetes and obesity, perhaps one day taking the form of a pill that could melt away the pounds without the hassle of a workout.

But new research from an international team of scientists has found that the antibodies used to measure levels of irisin in blood were poorly vetted and nonspecific. These researchers argue that the irisin levels reported by commercial kits were actually due to unknown blood proteins, misconstruing the role of the hormone in human metabolism.

The study, appearing March 9 in the journal Scientific Reports, directly tested the antibodies used in previous analyses and showed that they cross-reacted with proteins other than irisin, yielding a false positive result. Furthermore, none of the proteins detected by these test kits in any human or animal blood samples were the correct size to be irisin.

http://www.nature.com/srep/2015/150309/srep08889/full/srep08889.html

"From the start, the study of irisin has been complicated by unvalidated reagents and contradictory data that have raised flags about the existence of irisin and its role in humans and other species," said Harold P. Erickson, Ph.D., an author of the study and professor of cell biology and biochemistry at Duke University School of Medicine. "We provide compelling evidence that the signals reported by previous studies were due to non-specific blood proteins, not irisin. Hopefully, our findings will finally convince other researchers to stop chasing a myth."

Comment by Dr. Krishna Kumari Challa on March 11, 2015 at 9:44am

Blood group O protects against malaria- here is how:

It has long been known that people with blood type O are protected from dying of severe malaria. In a study published in Nature Medicine, a team of Scandinavian scientists explains the mechanisms behind the protection that blood type O provides, and suggest that the selective pressure imposed by malaria may contribute to the variable global distribution of ABO blood groups in the human population.

It has long been known that people with blood type O are protected against severe malaria, while those with other types, such as A, often fall into a coma and die. Unpacking the mechanisms behind this has been one of the main goals of malaria research.

A team of scientists led from Karolinska Institutet in Sweden have now identified a new and important piece of the puzzle by describing the key part played by the RIFIN protein. Using data from different kinds of experiment on cell cultures and animals, they show how the Plasmodium falciparum parasite secretes RIFIN, and how the protein makes its way to the surface of the blood cell, where it acts like glue. The team also demonstrates how it bonds strongly with the surface of type A blood cells, but only weakly to type O.

Principal investigator Mats Wahlgren, a Professor at Karolinska Institutet’s Department of Microbiology, Tumour and Cell Biology, describes the finding as “conceptually simple”. However, since RIFIN is found in many different variants, it has taken the research team a lot of time to isolate exactly which variant is responsible for this mechanism.

The mechanism behind the protection that blood group O provides against severe malaria, which can, in turn, explain why the blood type is so common in the areas where malaria is common. In Nigeria, for instance, more than half of the population belongs to blood group O, which protects against malaria.”

Evolution - on the move!

RIFINs are adhesins implicated in severe Plasmodium falciparum malaria

http://www.nature.com/nm/journal/vaop/ncurrent/full/nm.3812.html

My mother had severe cases of Malaria - not once but 5 times in 2 years some 15 years back! She had a temperature of 104 -107 degrees. We were very worried. And the malaria she got was caused by drug resistant Plasmodium falciparum.

But luckily she survived, now I know the reason. She is O+ve!

Comment by Dr. Krishna Kumari Challa on March 11, 2015 at 9:29am

Comment by Dr. Krishna Kumari Challa on March 11, 2015 at 9:27am

Comment by Dr. Krishna Kumari Challa on March 10, 2015 at 7:34am

Comment by Dr. Krishna Kumari Challa on March 7, 2015 at 6:11am

Comment by Dr. Krishna Kumari Challa on March 7, 2015 at 6:07am

Comment by Dr. Krishna Kumari Challa on March 7, 2015 at 6:01am

Human chimerism occurs when two eggs are released by the mother and are fertilised by two sperm from the father. Normally, this would result in fraternal, non-identical twins, but on rare occasions, these eggs can overlap and fuse to develop into one person who contains two different sets of DNA.

This can cause a person to have two different blood types simultaneously, or to develop both male and female genitals. A DNA sample taken from a chimeric person’s kidney could be completely different from a sample taken from her cervical tissue - an issue that has caused much grief in women trying to prove that they are in fact their children’s biological mothers.

According to researchers at Stanford University in the US, in some cases, chimeric people will have skin made up of two different types of skin cells, encoded by two different sets of DNA. This DNA is responsible for skin tone, which is how patterns can occur. "Often the skin colour of the two types is indistinguishable, or subtle enough that it can only show up under black light”. "Sometimes, however, the two different sets of DNA code for skin types that are dramatically different, which leaves people with literal stripes on their skin in the pattern of Blaschko's lines."

Comment by Dr. Krishna Kumari Challa on March 6, 2015 at 7:00am

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