Dear Dr. Roach: What, if any, is the difference between a “TIA” and a “ministroke”? I have since pressed my neurologist on the issue, and he said, “A TIA is an event you are aware that you are having; ministrokes are events you are not aware of at the time; they are only identified by an MRI.” This made some sense to me, but I have never seen the distinction elsewhere. All the websites I read called the two terms synonymous.
Do you agree with my neurologist?
Dear Anon.: The term “ministroke” is misleading, and I don’t use it.
The difference between a stroke and a transient ischemic attack is that in a TIA, the brain tissue recovers, usually within 24 hours, while a stroke is a permanent loss of brain tissue. The brain has the ability to recover function in some cases, as different parts of the brain can take over the function of the part of the brain that was damaged.
A stroke can be “silent,” with no perceptible loss of function to the person experiencing it, or it can cause any level of disability from mild to catastrophic. Your neurologist is referring to clinically silent strokes when he talks about ministrokes.
Both TIA and strokes call for an urgent assessment of how to reduce risk of a further, potentially devastating event. This includes lifestyle changes (smoking, alcohol, exercise, diet, stress), control of any predisposing conditions (such as high blood pressure and diabetes, if present), and sometimes medication, such as aspirin or clopidogrel (Plavix).
Dear Dr. Roach: I had two teeth implanted using human cadaver bone, due to bone loss. Did I get a transfer of that person’s DNA in the process, and if so, how would it affect my genetics?
Dear P.G.: Yes, the bone cells that came along with the teeth have the donor’s DNA. However, bone cells generally are stable, from a genetic standpoint, so the DNA is likely to sit there and not change the DNA of any of your cells.
That said, people who get different types of transplants can get donor DNA that may spread to other cells in the recipient’s body.
For example, a 2007 study of people who received a kidney transplant found that some of the donor DNA could be detected in blood cells even two years later.
It’s very much the same process as genetic transfer between mother and child: Most of us have a small amount of our mother’s DNA in some of our cells, and mothers may have some of their children’s DNA in their own bodies.
However, the germ cells (that’s oocytes, or eggs, in women; and spermatozoa of men) are relatively protected from foreign DNA.
It is very unlikely that you could pass on the DNA from your donor, your mother or your child.
Email questions to ToYourGoodHealth@ med.cornell.edu.