Low-Salt, Low-Meat Diet Shows Promise Against Kidney Stones
A diet low in salt and meat may be the best way to reduce the risk of having kidney stones, Italian researchers have found in a study that upsets the conventional wisdom that a low-calcium diet is the best preventive measure.
The Italian study found that the low-salt, low-meat diet reduced the risk of subsequent kidney stones by half in men who had had stones previously. The new diet recommendation will likely become the “gold standard” for people at risk, said William Keane, president of the National Kidney Foundation.
Doctors for years have told patients to reduce their calcium intake because most kidney stones are made of a calcium compound.
Dr. Loris Borghi and his colleagues at the University of Parma studied 120 men who had already had at least one kidney stone. Half were randomly assigned to the low-calcium diet and half to a diet that limited salt intake to 2,900 milligrams per day and meat intake to three-quarters of an ounce per day, plus an ounce of cheese or dairy products. Only men were studied because of the risk that the low-calcium diet would accelerate osteoporosis in women.
Men account for about 80% of all kidney stones, a highly painful condition that will affect about 10% of Americans at some time during their lives.
The team reported in the Jan. 10 New England Journal of Medicine that 23 men on the low-calcium diet experienced another kidney stone during the five-year study, compared to only 12 of those on the low-salt, low-protein diet. They conceded, however, that it would be difficult to get Americans to eat such low quantities of meat.
Serotonin-Enhancing Drugs Shouldn’t Be Mixed
The inadvertent use of drug combinations that increase levels of the neurotransmitter serotonin in the brain can lead to strokes due to narrowing of blood vessels in the brain, according to Boston researchers. Dr. A.B. Singhal and his colleagues at Massachusetts General Hospital report in the Jan. 8 Neurology on three patients who came to their emergency room with Call-Fleming syndrome, which is characterized by sudden-onset, severe (thunderclap) headaches, neurological problems and seizures.
The two women and a man were all taking several different serotonin-enhancing drugs at the same time, including medications for migraine, depression and colds. Among the drugs that should not be used in combination are antidepressants, anti-migraine agents, decongestants, diet pills, amphetamines, St. John’s wort, ecstasy, cocaine and methamphetamine, they said.
Study Yields Clue to Nursing Home Illness
Nursing home residents often develop gastrointestinal illnesses marked by severe diarrhea in winter, but researchers have never been sure of the precise cause of these outbreaks. A new study indicates that the most common cause may be a family of viruses called Norwalk-like viruses. The viruses may be much more common in nursing homes than previously recognized, according to researchers from the National Institute of Allergy and Infectious Diseases.
Dr. Kim Green and colleagues studied specimens obtained from 156 residents of a Maryland nursing home who became ill during the winter of 1987-88. Researchers at the time had looked for bacteria in the specimens, but found few, and the samples were frozen for storage. Using newly developed DNA techniques, the team reported in the Jan. 15 Journal of Infectious Diseases that 80% of the samples contained Norwalk-like viruses.
The Norwalk virus was first identified in 1972 in a stool sample obtained in Norwalk, Ohio. Researchers have since found a number of similar viruses that are called Norwalk-like viruses. They are responsible for many cases of gastrointestinal distress. The viruses are hard to study because they do not grow in laboratory animals or tissue cultures--only in humans. Researchers at NIAID are attempting to develop a vaccine against the virus.
HIV Linked to Risk of Cancer in Women
Women who are HIV-positive have a significantly increased risk of developing genital cancer, according to researchers from Columbia University. As many as 155,000 women in the United States are thought to be infected with the virus.
Dr. Tom Wright and his colleagues studied 925 women who had a gynecological examination twice yearly, with a follow-up exam three years later. At the initial exam, the team reported in the Jan. 12 Lancet, they found that HIV-positive women were six times more likely to have genital warts--a potential precursor of cancer--or very early stages of cancer than women who were HIV-negative. At the follow-up exam, the HIV-positive women were 16 times more likely to show the conditions. The team recommended that HIV-positive women be monitored closely by their gynecologists.
PET Scan Helps SpotEarly-Stage Alzheimer’s
UCLA researchers have found a new way to identify Alzheimer’s disease at its earliest stages, a finding that could help researchers monitor treatments. The team had previously shown that positron emission tomography (PET) scanning can identify the disease in most patients. They now report in the January American Journal of Geriatric Psychiatry that they have found a way to increase accuracy.
The key is a radioactive molecule called FDDNP. The molecule binds specifically to the plaques and tangles characteristic of Alzheimer’s, allowing researchers to visualize the markers accurately. An autopsy on one patient who died showed that FDDNP binds only to the plaques and tangles in the brain. The team is now applying to the Food and Drug Administration for permission to use the technique to check people who are at high risk of developing the disorder. The main drawback to the diagnostic test is the cost of PET scans, about $1,500, which is not normally covered by private insurance or Medicare for Alzheimer’s.
Transplant Waiting List Numbers in Thousands
The number of people needing organ transplants in the year that ended on June 30 was three times as high as the number who actually got them, according to new data from the Scientific Registry of Organ Transplants, which monitors such activity. While 23,360 people received transplants during that period, nearly 80,000 people remained on the registry waiting list as of June 30. More than 6,000 patients on the waiting list died before receiving transplants.
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Medical writer Thomas H. Maugh II can be reached at thomas.maugh@latimes.com.
