Digital rectal exam: A routine exam in which a physician inserts a lubricated, gloved finger into the rectum and feels for abnormal areas to detect rectal cancer and, in a man, inflammation, enlargement, or cancer of the prostate as well as nerve problems indicated by reduction of the normal tone of the muscles of the rectal sphincter.
- Dihydroorotate dehydrogenase
Dihydroorotate dehydrogenase: An enzyme necessary to pyrimidine synthesis and therefore essential to the production of DNA and RNA. The drug leflunomide (Arava), an immunomodulatory agent, acts by specifically inhibiting dihydroorotate dehydrogenase.
Dihydrotestosterone: A byproduct of the male hormone testosterone. Dihydrotestosterone (DHT) is considered to be the essential androgenic hormone. DHT is responsible for the formation of male primary sex characteristics during embryonic life. It is responsible for the development of most secondary sex characteristics in males at puberty. And it continues to be important to male […]
Dihydroxyacetone: Also known as DHA, the active ingredient in most sunless tanning lotions. See: DHA.
Dilatation: The process of enlargement or expansion. Also known as dilation.
- Dilated cardiomyopathy
A disorder in which the chambers of the heart are dilated (enlarged) because the heart muscle is weakened and cannot pump effectively. There are many causes, the most common being myocardial ischemia (not enough oxygen supplied to the heart muscle) due to coronary artery disease.