Q. The drug minoxidil seems to be a promising cure for baldness. It's currently in its testing stage and not available for this use in the United States. Is it possible to obtain minoxidil as a treatment for baldness in Mexico or Canada? Also, when will it become available on the U.S. market?

A. With or without minoxidel, there's still no cure for baldness.

Soon after doctors started using minoxidil (Loniten) -- a strong medicine used to treat tough cases of high blood pressure -- they noticed that some of their patients had increased hair growth. Experiments with a lotion made from the drug proved that it could stimulate hair growth in bald or balding areas.

The drug will probably be ready for prescription use about 1986 or 1987.

Although this lotion doesn't have Food and Drug Administration approval, you don't need to cross the border to get it. A few doctors are already having pharmacists make up the lotion using high blood pressure tablets.

Its chief drawbacks are that: It doesn't cure baldness; it only stimulates hair growth if it's applied every day. The cost of one month's supply of the tailor-made lotion could run as much as $100 to $300. Taken by mouth, minoxidil has had serious side effects, particularly heart damage in laboratory animals. It's too soon to know the long-term effects of topical minoxidil. It doesn't work for everyone. About one third of people develop near-natural hair growth, one third develop thin, sparse hair growth, and one third get no benefit.

Q. Recently I discovered a lump on my wrist. My doctor told me I had a ganglion and not to worry about it unless it bothered me. Please explain what a ganglion is, how one can prevent these from developing, and what can be done about the ones already formed.

A. A ganglion -- from a Greek word meaning swelling or knot -- is a harmless lump that sometimes develops on a hand, wrist or foot. Although lumps can be a warning sign of cancer, ganglia are not malignant and never turn into a cancer.

The lump is actually a swelling of either the synovium, the tough tissue lining the small joints in the wrists and feet, or the covering sheaths of tendons, the tough fibers that connect muscles to bones. A ganglion is filled with the thick, jelly-like fluid that lubricates joints.

Ganglia generally develop for no apparent reason, so there's nothing you can do to prevent them. But prevention isn't usually necessary, because once you have one, you're not likely to get another.

If the ganglion is small and its appearance doesn't bother you, you don't need to have anything done about it. If it's large or bothersome, your doctor may insert a needle to draw off the fluid and make the swelling go down. This may work, but in many cases, the ganglion returns.

An orthopedic or general surgeon can cut out the ganglion under local anesthesia, but even with surgery, the ganglion can sometimes come back.

Q. For the past few years, I've occasionally woken up at night in a cold sweat. This happens year round, but particularly in winter. I don't perspire during the day, and don't have any fevers. I'm worried because I've heard that people with TB sweat at night. What could the problem be?

A. It's true that night sweats are a telltale sign of tuberculosis, but it's very unlikely that you have it. If you did, or if you had another serious disease, more symptoms would almost certainly have shown up by now.

Among the more worrisome causes of night sweats are infections like tuberculosis, lymphoma (lymph gland cancer) and heart failure. TB and lymphoma generally produce fever, weight loss and tiredness, and heart failure makes you short of breath.

Other causes of night sweats are: a warm room or too many covers on the bed; dreams or nightmares; anxiety and nervousness; hyperthyroidism (overactive thyroid gland); side effects of certain medications, such as Urocholine; alcohol withdrawal symptoms.

If none of the above apply to you, and you've had occasional night sweats for years without anything turning up on a doctor's exam, I think it's unlikely that you have anything serious.