DEAR DR. DONOHUE: I have had Type-2 diabetes for many years. I take oral medicine for it. I took the A1C blood test, and my score was 5.8. The nurse told me it “was down the middle.” What does this mean? – J.A.

ANSWER: A1C is hemoglobin, and the test is often called hemoglobin A1C. Hemoglobin is a giant protein within every red blood cell that grabs onto oxygen as blood passes through the lungs. When blood gets to areas of the body in need of oxygen, hemoglobin releases its grip on it.

Blood sugar also sticks to hemoglobin. The higher the blood sugar and the longer it remains high, the higher the A1C readings. The A1C is a good measure of blood-sugar control over the past two to three months.

One official group accepts as normal an A1C level of 7 percent. Another group prefers it to be 6.5. And the strictest group wants it 6 or lower.

No matter what group you judge your reading by, your value is fine.

I don’t know what the nurse meant by “down the middle.” I do know you have nothing to worry about. How about asking her what this means and letting me know? Curiosity consumes me.

DEAR DR. DONOHUE: I am a 61-year-old male who has had Type-2 diabetes for seven years. Since the beginning, I have been on oral medication, but my doctor would like me to start insulin now. I am overweight – 300 pounds, 6 feet tall.

What will the real difference be for me if I start insulin shots instead of continuing with oral medication? I am a wimp when it comes to needles and syringes. Will my “interior” deteriorate faster if I do not go on insulin, and will insulin give me a “new” life, as somebody claims? – P.R.

ANSWER: Oral medicine must not be keeping your blood sugar in control. Good control of blood sugar can prevent many of the terrible complications of diabetes – premature heart disease; nerve damage; poor circulation to the legs and feet, sometimes necessitating amputation; and possible blindness.

Insulin will give you a new lease on life.

You must deal with your weight. Fat blunts the action of insulin. If you lose a considerable amount of weight, you might not have to continue with insulin. You need the help of a nutritionist, and you need a serious exercise program to achieve that goal.

DEAR DR. DONOHUE: In March of this year, I was diagnosed with myasthenia gravis. My age is 87. My medications are pyridostigmine during the day and Mestinon at bedtime. This medicine gives me severe diarrhea. I lost 10 pounds in three months. Is there anything I can do? – N.D.

ANSWER: Myasthenia can begin at any age, but it is not common for it to happen to someone at age 87.

The problem in myasthenia is the inability of nerve signals to cause muscle action. Nerves release a chemical called acetylcholine. When the chemical swims across a small gap between the nerve and muscle and lands on the muscle, it causes a muscle contraction. With myasthenia, there is too little acetylcholine landing on muscle to cause a strong muscle contraction. The result is muscle weakness that shows up in a number of ways – droopy eyelids, difficulty chewing and swallowing, and weakness of the leg and arm muscles.

You are taking standard myasthenia medicines. Pyridostigmine increases the amount of acetylcholine that gets to muscle. Mestinon (a brand name for pyridostigmine) is an extended-release form of the drug that helps you get through the night.

Does your doctor know you are suffering from such severe diarrhea and have lost so much weight? The dose of medicine might need to be adjusted. Or perhaps a substitute medicine could be used for a short time. Prednisone works, but it has its own list of side effects. Other medicines include azathioprine and cyclosporine.

DEAR DR. DONOHUE: In your article on polycythemia, you failed to mention hydroxyurea. I cannot have blood drawn, and this medicine has controlled my illness for five years. – L.A.

ANSWER: Polycythemia is too many blood cells, especially red blood cells. Removing blood from time to time is a safe treatment for it, but hydroxyurea works for those who cannot have blood removed.

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.