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Best Time to Take Cancer Drugs? When Your Body Says So, Report Shows


Cancer drugs are more effective when administered at the peak of the body's biorhythms than when infused continuously, French physicians report in the Lancet. The team studied 186 patients with colorectal cancer who were receiving oxaliplatin, fluorouracil and folinic acid. Half received constant infusion of the drugs and half received variable doses that coincided with circadian rhythms.

Those receiving the drugs in concert with their biorhythms had only one-fifth the rate of intestinal distress and half as much peripheral nerve damage as those who received it continuously. Their median time to treatment failure was 6.4 months, compared to 4.9 months for the control group.

Test Tied to Clubfoot

Chorionic villus sampling can cause clubfoot when used in the 12th week of pregnancy, Danish physicians reported in the Sept. 6 Lancet. The team prematurely stopped its study of the technique--used for detecting genetic abnormalities--because of the increased incidence of foot deformities.

The team assigned 579 pregnant women to chorionic villus sampling at 10 to 12 weeks and compared the results with 581 women given conventional amniocentesis at 11 to 13 weeks. Researchers found significantly more cases of clubfoot in the chorionic villus sampling group, apparently caused by a leakage of amniotic fluid after sampling. The technique has not been associated with an increase in abnormalities when used later in gestation.

Easier-to-Use Heparin

A new, easier-to-use form of the blood thinner heparin, called low-molecular-weight heparin, is safe and effective for people with blood clots in their lungs or recurring clots in their veins, according to two studies in the Sept. 4 New England Journal of Medicine. Low-molecular-weight heparin is fast becoming the standard treatment for preventing blood clots after surgery and for treating heart disease patients.

Ordinary heparin requires hospitalization because it is given intravenously and the dosage varies and often needs to be adjusted during treatment. Low-molecular-weight heparin is injected and can be used on an outpatient basis. Patients with a history of blood clots in their veins or in the arteries of the lungs have previously been excluded from use of the drug because of their higher risk.

Alzheimer's Genes

Researchers at Harvard Medical School have discovered the function of two genes, called presenilin 1 and 2, that cause a familial form of Alzheimer's disease. Neurobiologist Huntington Potter and his colleagues report in the Sept. 5 Cell that proteins produced from the genes play a crucial role in the segregation of chromosomes, a key step in cellular replication.

Humans have 23 pairs of chromosomes, which contain the human genetic blueprint. When cells reproduce, each chromosome is duplicated. The old and new chromosomes are then pulled apart by specialized structures to give two complete sets, one for each cell. Potter thinks defects in the presenilins create cells with abnormal numbers of chromosomes, which can then cause disease.

Fertility Research

Geneticists have found a gene for both male and female fertility that could help explain why one in six couples has difficulty conceiving children. Howard Cooke and a team at the Medical Research Council Human Genetics Unit in Edinburgh, Scotland, identified a gene in mice called DAZLA that is related to the male infertility gene, is inherited by males and females, and can affect fertility in both sexes.

Reporting in the Sept. 4 Nature, Cooke said that when they removed the DAZLA gene from the mice of both sexes, the animals were still healthy but infertile. Males could not produce sperm, and females were incapable of making eggs--indicating that the gene is seemingly essential for the reproductive development in both sexes.

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