 Why Homosexuality May Be in One's Genes
Milk for SARS, tea for Alzheimer, stem cells for anemia
"MIRACLE CURE" FOR ANEMIA?
PARIS
A small British biotech firm is battling mainstream scientific opinion after claiming to have made an accidental discovery into stem cells that could revolutionize medicine.
The company, TriStem, contends that, with its first tests on humans, it has been able to rescue patients suffering from a vicious form of anemia who were on the brink of death. "If they are valid, the firm's scientists could have made a breakthrough comparable to Alexander Fleming's discovery of penicillin," New Scientist reported of the discovery in October.
The work focuses on stem cells, the "blank slates" which later differentiate into the specialist cells that make up the body's tissues. The great hope of scientists working in this area is that stem cells can be harvested and then coaxed into growing into specific tissue, thus providing a treatment for degenerative diseases such as Alzheimer or Parkinson, reversing liver damage or fixing damaged hearts. But progress has been slow, hampered by lack of knowledge as to how the cells differentiate and ethical rows over embryonic stem cells, the most versatile material of all.
TriStem's approach is radically different from that followed by mainstream researchers, many of whom are suspicious or outright dismissive of the firm's claims, New Scientist said. The apparent breakthrough was discovered by accident in 1990, when leukemia researcher Ilham Abduljadayel was experimenting with a commercially made antibody called CR3/43 and immune-system molecules that destroy cells that are bound to antibodies.
In one experiment, she accidentally forgot to add the immune molecules--and discovered that the dark leukemia cells, after being immersed in the antibody solution became transparent and flourished. The antibodies had somehow reversed the cells' differentiation, turning them into bone-marrow stem cells, a phenomenon that amounted to biological heresy, according to Abduljadayel. "At first, I thought I was going nuts. I repeated it again and again," she said.
Although they found no support for their research and even less a journal in which to publish their findings, Abduljadayel and her husband took out patents on the discovery in 1994 and founded TriStem to commercialize it.
Further work, according to TriStem, has enabled the "retro-differentiation" to go back even further, turning back the clock so that bone-marrow stem cells become as versatile as embryonic stem cells. And by exposing these cells to growth factors already widely used in conventional stem-cell research, Abduljadayel says she could produce in the lab almost any kind of tissue.
In their first experiment on humans, TriStem gained permission from the Indian authorities to try the technique on four patients in Mumbai with severe aplastic anemia, a condition where the bone marrow stops making enough red blood cells, immune cells, and platelets. All four, who needed frequent blood transfusions just to stay alive, had "spectacular recoveries" within three weeks of having their immune cells treated with the antibody, New Scientist said.
But mainstream researchers remain skeptical. Major doubts remain over the core of the claim about the conversion to the state of stem cells, and critics insist that major, controlled trials are needed to prove that the technique is not only effective but safe, the report said.
MATERNAL GENES LINKED TO HOMOSEXUALITY
PARIS
Genes handed down by one's mother and having a large number of older brothers may determine whether someone is a homosexual, according to a study. Put together, these two factors may account for perhaps 20 percent of the prevalence of homosexuality, although social and cultural influences probably make up most of the rest, it suggests.
Psychologists at the University of Padova asked 98 homosexual men and 100 heterosexual men in northern Italy to fill out a confidential questionnaire detailing their sexual orientation and that of their siblings, first cousins, parents, aunts, uncles, and grandparents.
AmonfÖ4he homosexuals, 22 out of the 396 male relatives on the maternal line of their family were gay, as were 12 out of 593 on the paternal side. Among the heterosexuals, none of the 370 male relatives on the maternal line was gay; on the paternal line, the number was eight out of 604.
Just as striking was the relationship between birth order and sexual orientation.
In large families, homosexuals were likelier to have been born second, third, fourth, or later, and were far likelier to have older male siblings rather than older sisters.
The study, led by Francesca Corna, says this adds statistical support to hypotheses about possible genetic causes for homosexuality, although it did not investigate homosexuality in women.
Previous research, carried out among gay brothers, suggests a link between homosexuality and a genetic sequence called Xq28 on one of the arms of the X chromosome, one of the chromosomes that determines sex.
Research published in the mid-1990s bred the theory, strongly contested by some, that the male fetus presents an antigen, a molecule that triggers a response from the woman's immune system.
With each successive male birth, the mother is successively immunized against this antigen and the subsequent chemical change in the uterus has an effect on the sexual differentiation of the fetus.
An architect of this hypothesis, Canadian scientist Ray Blanchard, has calculated that each additional older brother increases the odds of homosexuality in the next male by 33 percent.
Corna's team stresses that cultural and social factors, in addition to genes, also powerfully shape sexual orientation.
"Over 79 percent of the variance in male sexual orientation, in our sample, remains unaccounted for by the factors of excess of maternal homosexual kin and number of older brothers," they note.
They wonder if child-raising traditions in northern Italy could help mold sexual orientation and behavior. Aunts, mothers and grandparents spend lots of time with the child in his young formative years.
"Our findings, if confirmed by further research, are only one piece in a much larger puzzle on the nature of human sexuality."
While acknowledging that the Nature-versus-Nurture debate about homosexuality will continue to rage, the authors believe they may have resolved one of the enigmas about homosexuality. This is the so-called Darwinian paradox: if homosexuality is conferred in part by genes, why haven't these genes been progressively eliminated over the millenniums by natural selection--the process that prefers genes which are useful for reproduction and survival?
The answer could lie in Xq28, for the mothers of homosexuals could be exceptionally fertile. In other words, this particular genetic variation is a Darwinian tradeoff--there is low or zero fecundity among men because they are homosexuals, but high fecundity among women.
The study appears in Proceedings of The Royal Society B, a journal published by the Royal Society, Britain's leading scientific association.
MILK MIGHT BE KEY TO SARS VACCINE
SINGAPORE
Singapore scientists working to develop an edible vaccine for viruses such as the severe acute respiratory syndrome (SARS) have found a breakthrough in milk. Researchers have successfully immunized mice from a virus similar to SARS by feeding them with genetically modified lactic-acid bacteria, which is found in cultured milk drinks, the Straits Times reported.
This could mean that in a few years, doctors will be able to dispense a SARS vaccine that could simply be eaten or drunk, the principal investigator of the study, associate professor Lee Yuan Kun, said.
"This will bypass people's fear of needles and the need for trained staff to do injections, and is a cheap and effective way to do mass immunization," the Straits Times quoted him as saying. "The idea is that if you can drink it or eat it, it will reach a wider audience, particularly in developing countries which need them the most."
The scientists first cloned a surface protein of a virus belonging to the coronavirus family that includes SARS, into lactobacillus casei bacteria.
Mice that were fed the concoction were seen to develop antibodies that protected them from subsequent infections.
The research team, which has been working on the project for three years, has already performed a similar cloning of the SARS virus into bacteria and yeast cells. Testing on animals will be done soon, with clinical testing to follow in a few years, Lee said.
The United States and China are also developing "traditional" injection-delivered vaccines, with China already testing the results on volunteers.
AN AFTERNOON TEA TO REMEMBER
LONDON
A steaming cup of tea could help ward off the effects of Alzheimer disease (AD). Laboratory tests found that taking regular cups of green and black tea inhibits the activity of certain enzymes in the brain that bring on AD.
The research by the Medicinal Plant Research Center at Newcastle University, northeast England, is published in the academic journal Phytotherapy Research.
Scientists tested coffee as well as green and black tea, the latter of which--the variety enjoyed by most Britons--is derived from the same plant as the green variety but has a different taste and appearance as it is fermented. The results found that while coffee had no significant effect, both green and black tea inhibited the activity of acetylcholinesterase (AChE), which breaks down the chemical messenger, or neurotransmitter, acetylcholine. AD is characterized by a drop in acetylcholine.
Green tea and black tea also hinder the activity of the enzyme butyrylcholinesterase (BuChE), seen in protein deposits found on the brains of patients with AD. However, green tea alone had a further effect, obstructing the activity of beta-secretase, which has a role in the production of protein deposits in the brain associated with AD. The effects of green tea also last for a week, scientists found, as against only a day for black tea.
"Although there is no cure for Alzheimer, tea could potentially be another weapon in the armory which is used to treat this disease and slow down its development," said head researcher Dr. Ed Okello. "Our findings are particularly exciting as tea is already a very popular drink, it is inexpensive, and there do not seem to be any adverse side effects when it is consumed. Still, we expect it will be several years until we are able to produce anything marketable."
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