DEAR DR. DONOHUE: Would you explain what gastroparesis is and what treatment is available for it? – L.T.

ANSWER: When everything functions correctly, solid foods leave the stomach in three to four hours. Gastroparesis is the condition in which it takes the stomach much longer to empty. You can call it a sluggish stomach. The slow emptying gives rise to many symptoms. One is a feeling of fullness after eating only a small amount of food. Nausea and vomiting are other consequences. Reflux of food into the esophagus can be common with it. Sometimes there is stomach pain.

Diabetes is one of the biggest causes of gastroparesis. Diabetes destroys the nerves that control stomach contractions. Gastroparesis in a diabetic creates problems in blood sugar control. Carbohydrates leave the stomach so slowly that they don’t have a chance to counter the effect of blood-sugar-lowering diabetes medicines and insulin.

Stomach surgery, neurological diseases, thyroid problems, multiple sclerosis, Parkinson’s disease and scleroderma are examples of other illnesses that lead to gastroparesis. It’s not an uncommon condition.

Treatment includes small, frequent meals that are low in fat. Fat slows the passage of food through the stomach. Liquid supplements like Ensure can be used to advantage by people with this problem. The medicine Reglan can speed stomach emptying. Two other medicines prescribed are domperidone and the antibiotic erythromycin.

There is a device, much like a heart pacemaker, that delivers electric impulses to the stomach muscles to get them contracting more frequently and forcefully.

DEAR DR. DONOHUE: My mother, who lives in Singapore, has been undergoing treatment for wet macular degeneration since 2001. I am worried it is getting worse.

I understand there is a new drug, Lucentis, that the eye doctor can inject into the eye, and it is supposed to work well. Where can my mother get treatment in America? Can my insurance cover her medical costs? – S.M.

ANSWER: The Food and Drug Administration approved Lucentis (ranibizumab) in June 2006 for the treatment of wet macular degeneration. The macula is the most sensitive part of the retina, the kind needed for fine vision like reading, writing, driving and watching TV. “Wet” macular degeneration is the less-common kind of this illness. It constitutes only 10 percent of all macular degeneration. Wet degeneration comes about from the sprouting of fragile blood vessels in the macular area. Those vessels leak fluid and blood and destroy the macula’s ability to transmit clear images to the brain. This is the kind of macular degeneration that often progresses rapidly.

Lucentis stops the action of body-made substances that promote the growth of new macular blood vessels. The drug is injected into the eye. Not only can it slow the progression of wet macular degeneration, but it has actually improved vision for some patients. Promises can never be made for any treatment, but Lucentis looks like a valuable addition to the other treatments used for wet macular degeneration.

Other treatments include photodynamic therapy. A drug that sensitizes the walls of these fragile new vessels to a laser beam is injected into a vein. The abnormal macular blood vessels absorb the drug. When the doctor shines the laser beam on them, they shrivel and die.

I can’t tell you if your insurance will cover your mother. Your insurance company can answer that question for you. You live in a large city. I am sure many eye doctors in that city are capable of injecting the new drug. There’s also a large medical school there, and its department of ophthalmology will have a doctor skilled in this treatment.

DEAR DR. DONOHUE: You’re right that bottled water doesn’t cause cavities but, since it doesn’t have fluoride, it doesn’t protect teeth like fluoridated tap water does. – G.W., D.M.D.

ANSWER: Thanks so much, doctor. That’s a very important point. I hope the letter writer reads this. I should have made a comment about it.

DEAR DR. DONOHUE: I’m a 75-year-old woman who had an angioplasty about 10 years ago and then triple bypass surgery on my heart arteries later. I do not recall anything about the angioplasty. Now I’ve been told I have a plaque deposit on a leg artery, and I am scheduled for angioplasty on that artery. What are the dangers, the time for recovery and the anesthesia? – J.P.

ANSWER: The angioplasty on your leg artery will be the same as the angioplasty on your heart artery. The procedure involves inching a thin, pliable, balloon-tipped, soft tube through a groin artery into the leg artery where the obstruction is located. When the doctor reaches the point of obstruction, he or she inflates the balloon to squash the obstruction and re-establish blood flow.

It’s possible things could go wrong. The artery could be damaged. You could bleed. An infection could follow. However, most of the time, things go very smoothly, and often people are home the next day. You can be up and about then. Often, only a local anesthetic is needed, and you are lightly sedated during the procedure.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from www.rbmamall.com.