Your health this month.

Your health this month.

Your health this month.

Health and medicine explained.
July 1 2005 3:39 PM

Your Health This Month

Mercury in vaccines and dental fillings, avian flu, episiotomies, and more.

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Diabetes: Saving the cells that make insulin.

State of the Science: More than 14 million patients in the United States have diabetes, which requires lifelong insulin injections and attention to diet and medical care and if untreated results in these complications. Diabetes is caused by malfunctions in the production of insulin (Type 1) or its utilization (Type 2). Insulin is a hormone that controls the entry of sugar into many kinds of body cells. When things are going right, it is manufactured by "beta cells" in the pancreas. But in Type 1 diabetes—5 to 10 percent of cases, most of them children or young adults—the body fails to produce insulin because of a perversion of the immune system. With this autoimmune disease, T lymphocyte cells—which normally identify and destroy abnormal cells—are misdirected and attack the pancreatic beta cells. The cause is unclear; many doctors suspect a combination of genetic susceptibility and perhaps a virus infection as the trigger.

Prognosis: Immune-suppressant drugs can stop the destruction of beta cells, but at great cost: They need to be administered forever, and they block the body's ability to fend off viral and bacterial infections and to eliminate malignant cells that develop into cancer. A recent little-noticed study by Bart Keymeulen of Brussels Free University offers hope of a better alternative. Keymeulen and his colleagues selected diabetics early in the development of their disease—before all their beta cells had been destroyed—and injected a highly purified antibody that attaches only to T lymphocyte cells. Without treatment, these patients would have gone on to lose all their insulin-producing cells and become severely diabetic. But after less than a week of the treatment, the haywire T cells seemed to lose interest in attacking the insulin-producers, and the destruction somehow abated. The effects remained powerful 18 months later.

If Keymeulen's experimental treatment can be developed for safe clinical use, expect a definitive treatment for Type 1 diabetes that halts the destruction of insulin-producing cells when begun early enough. In that event, the disease would be far milder, though treatment would still be required. Ultimately, embryonic stem-cell research may succeed in fully correcting Type 1 diabetes by replacing the killed-off beta cells with new ones. That advance could make the lives of diabetics completely normal.

Caveat: This promising new treatment, which needs much more refinement and testing before it is ready for general use, will surely be costly. The technology is expensive to develop, and there will be an added surcharge to reflect what the market will bear. But (as the makers know) at any reasonable price the treatment will be perceived as a bargain compared with the estimated $1,000 per patient per year that diabetes presently costs to manage.

Bird flu: This is what you should worry about.

State of the Science: If you ask infectious-disease experts to identify the two biggest challenges immediately facing medicine, most would name a coming influenza pandemic and the loss of effective antibiotics because of increasing resistance. In a way, we may be approaching a confluence of those two concerns.

Presently, the H5N1 strain of type A flu is decimating chicken flocks throughout Asia. This strain has so far rarely crossed over to infect humans and probably has genes that don't efficiently promote human infection. But there is great concern that one day it will co-infect a human patient carrying a human flu infection and that a resulting combination will produce a highly infectious and lethal new human flu. A recombination between human flu and flu from some mammal, most likely a pig, probably resulted in the devastating Spanish Influenza pandemic that killed between 50 million and 100 million people in 1918.

Prognosis: If H5N1 does develop a human strain, we are in big trouble. The virus is almost 100 percent lethal when it sweeps through flocks of chickens and has killed about half of the 50 or so people who have so far been infected. We will never be able to make, distribute, and administer enough vaccine fast enough to make a significant dent in a worldwide epidemic. The best hope is to widely distribute an inexpensive, safe, and effective chemoprophylaxis drug, which cuts down the risk of serious influenza by interfering with the virus particle's ability to attach to a host cell or to multiply in it. The least-expensive and most-available of these drugs is perhaps amantadine (which, by the way, probably has the most beautiful chemical structure of any medication).

Caveat: The trouble is that Chinese farmers are sprinkling amantadine into the drinking water of their chicken flocks, probably with local government complicity. This thoughtless, nonsensical, and dangerous practice has been shown to have the predicted effect: H5N1 influenza virus in China and Vietnam has become resistant to amantadine. If H5N1 emerges from Asia as an efficient and virulent human pathogen, we will have lost the best tool we had to limit the devastation. And that would be the confluence of the two big fears of infectious disease experts—a new flu pandemic and widespread resistance to treatment because of thoughtless use of a prophylactic drug.

Episiotomy: Think twice.