DEAR READERS: In yesterday's column I said that, theoretically, embryonic stem cells could be used to replace cells that are killed by disease -- heart cells killed in a heart attack, for example, or brain cells killed by Alzheimer's disease. If you needed stem cells, what you would ideally want were your own embryonic stem cells. The dilemma: Your own stem cells existed only briefly, long ago, and you couldn't turn back the clock. That is, until a research breakthrough in 2007 showed that you could.
DEAR DOCTOR K: People have been talking about stem cells as a revolutionary technique for a long time. Has anything come of it? And why has it been so controversial?
DEAR READER: You're right; people have been excited about stem cells for nearly 25 years. Yet progress was quite slow, and some people had major ethical concerns. But in the past eight years, progress has accelerated and the ethical issues largely have been circumvented. Theoretically, stem cells could be used to replace cells that are killed by disease -- heart cells killed in a heart attack, or brain cells killed by Alzheimer's disease. But to explain the exciting potential of stem cells, I need first to define some terms and concepts.
DEAR DOCTOR K: My teenage daughter has had Type 1 diabetes since she was 8 years old. Fortunately, exercise, a good diet and insulin treatments have kept her healthy. I recently heard of a breakthrough at Harvard that might someday cure Type 1 diabetes. Can you explain?
DEAR READER: The research you're referring to was conducted in the Harvard laboratory of Dr. Douglas Melton. Like you, Dr. Melton has a child with Type 1 diabetes. When his child became sick, he redirected his laboratory to the goal of finding a cure.
DEAR DOCTOR K: I have a particular disease. A nearby medical school is recruiting people with my condition to participate in a research study. Should I volunteer?
DEAR READER There are two good reasons to consider volunteering for a study: It might help you, and it might help others. In some types of studies, there also may be risks to you. Sometimes my patients ask me: "Do we really need to do all these medical research studies?
In yesterday's column, a reader asked whether she should be tested for genes linked to Alzheimer's disease. Today, I thought I'd give you my view on the larger question: Will studies of our genes change the practice of medicine and improve our lives?
My answer: During my career, progress in human genetics has been greater than virtually anyone imagined. However, human genetics also has turned out to be much more complicated than people imagined. As a result, we have not moved as rapidly as we had hoped in changing medical practice.
DEAR DOCTOR K: In a recent column about abdominal fat, you talked about two kinds of fat -- brown fat and white fat. I'd like to hear more about them.
DEAR READER: I'm glad you asked, because the discovery of these two types of fat could prove to be very important. In the column you're referring to, I discussed how visceral, or abdominal, fat (which accumulates deep inside the abdomen) is more harmful to our health than subcutaneous fat (the fat just beneath the skin). But when it comes to fat, it's not just location that matters. Color counts, too -- and brown is better.
DEAR DOCTOR K: I have prostate disease and treatment hasn't worked. My doctor suggested I participate in a clinical trial. I'd like to know more before I give him an answer.
DEAR READER: When established treatments aren't effective, participation in a clinical trial can be a good option. Such trials give you access to promising treatments that might work better than one already on the market. On the other hand, clinical trials test treatments that are still under investigation. There may be unpleasant or serious side effects. Clinical trials are designed to minimize risks to participants, but they cannot completely eliminate them.
DEAR DOCTOR K: Is the chemical BPA just another health scare? Or is it really something I should be worried about?
DEAR READER: BPA stands for bisphenol A. It is used to make a plastic known as polycarbonate. Polycarbonate is sturdy and resists shattering, so it's a great material for water and baby bottles. BPA is also used to line the inside of cans so the metal of the can doesn't directly touch the food or beverage. It's used in some dental sealants and as an ingredient in the paper on which many receipts are printed. So there's no question that we're exposed to BPA.