Thursday, October 25, 2012
Mitochondrial defects affect an estimated 1 in 4,000 children, and can cause rare and often fatal diseases such as carnitine deficiency, which prevents the body from using fats for energy.
They are also implicated in a wide range of more common diseases affecting children and adults, such as multiple sclerosis and Parkinson’s disease. Mitochondria have their own DNA and are inherited only from the mother, so replacing defective mitochondria in eggs from mothers who have a high risk of passing on such diseases could spare the children.
Three years ago, a team led by Shoukhrat Mitalipov, a reproductive biologist at Oregon Health and Science University in Beaverton, created1 eggs with donor mitochondria that developed into healthy rhesus monkeys (Macaca mulatta). Today, the same team reports2 the creation of human embryos in which all of the mitochondria come from a donor. The method needs to be tweaked to increase efficiency and gain regulatory clearance, but it is ready for the clinic, says Mitalipov. “You can expect the first healthy child to be born [using this method] within three years.”More in Nature
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Tuesday, October 23, 2012
Friday, October 19, 2012
Tuesday, October 16, 2012
Adam Frank in the NYTimes this past weekend on the new Nobel Prize in physics and quantum computing:
What does this all mean in practice? Take one area where quantum information theory holds promise, that of quantum computing.
Classical computers use “bits” of information that can be either 0 or 1. But quantum-information technologies let scientists consider “qubits,” quantum bits of information that are both 0 and 1 at the same time. Logic circuits, made of qubits directly harnessing the weirdness of superpositions, allow a quantum computer to calculate vastly faster than anything existing today. A quantum machine using no more than 300 qubits would be a million, trillion, trillion, trillion times faster than the most modern supercomputer.
Going even further is the seemingly science-fiction possibility of “quantum teleportation.” Based on experiments going on today with simple quantum systems, it is at least a theoretical possibility that one day objects could be reconstituted — beamed — across a space without ever crossing the distance.
When a revolution in science yields powerful new technologies, its effect on human culture is multiplied exponentially. Think of the relation between thermodynamics, steam engines and the onset of the industrial era. Quantum information could well be the thermodynamics of the next technological revolution.
at 4:09 PM
Saturday, October 6, 2012
Friday, October 5, 2012
Psychological anthropologist Tanya Marie Luhrmann, author of When God Talks Back: Understanding the American Evangelical Relationship with God (reviewed here) writes in the Wilson Quarterly about the social aspects of schizophrenia, highlighting some anthropological research done on schizophrenia within migrant populations:
The most remarkable recent epidemiologic finding relates to migrants: Some fall ill with schizophrenia not only at higher rates than the compatriots they leave behind, but at higher rates than the natives of the countries to which they have come. Dark-skinned migrants to Europe, mostly from the Caribbean or sub-Saharan Africa, are at risk of developing schizophrenia at rates as much as 10 times higher than those of white Europeans. This is a dramatic increase, and it has been shown by so many studies conducted with such methodological care that it cannot be dismissed as diagnostic racism, as if white clinicians confronted with angry black men simply called them “schizophrenic” (even though this sometimes happens). Nor does it seem that biology alone can explain the increased risk, although serious research is now being done to test the hypothesis that vitamin D deficiency plays a role.
Some observers think that the epidemiologic finding is a stark story about the way racism gets under the skin and drives people mad. It is probably more complicated than that. Another young anthropologist, Johanne Eliacin, spent two years doing fieldwork among African-Caribbean migrants living in London. Eliacin saw racism, and she felt viscerally her subjects’ stinging sense of being unwanted and out of place. But she also saw a social world shot through with hostility and anger, in which people were isolated and often intensely lonely. The African-Caribbean people in Tottenham spoke of there being no community in the community. They held up schizophrenia as the symbol of what had gone wrong. Yes, racism lay at the root of the problem, but the tangible distress was the sense of being hopelessly trapped.
Epidemiologists have now homed in on a series of factors that increase the risk of developing schizophrenia, including being migrant, being male, living in an urban environment, and being born poor. One of the more disconcerting findings is that if you have dark skin, your risk of falling victim to schizophrenia increases as your neighborhood whitens. Your level of risk also rises if you were beaten, taunted, bullied, sexually abused, or neglected when you were a child. In fact, how badly a child is treated may predict how severe the case of an adult person with schizophrenia becomes—and particularly, whether the adult hears harsh, hallucinatory voices that comment or command. The psychiatrist Jean-Paul Selten was the first to call this collection of risk factors an experience of “social defeat,” a term commonly used to describe the actual physical besting of one animal by another. Selten argued that the chronic sense of feeling beaten down by other people could activate someone’s underlying genetic vulnerability to schizophrenia.
at 1:46 PM