Glossary of Terms - d

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Terms

Deionized Water

Water that has had the ions removed. Used in laboratories for making reagents.

Deoxyribonucleic acid (DNA)

The carrier of genetic information, it is found on chromosomes in the cell nucleus. It is a complex protein composed of different subunits that contain nitrogen, a complex sugar, phosphoric acid, and other constituents arranged in specific sequences. Genes consist of DNA.

Dexamethasone suppression test (DTST)

A procedure to evaluate the neuroregulatory mechanism of cortisol secretion into blood plasma. following the administration of dexamethasone (a synthetic steroid which normally causes decreased secretion). Cortisol levels may be determined by various immunoassay methods. DTST is often done to help identify a depression disease, as patients may not suppress cortisol secretion after dexamethasone administration.

Diabetes Control and Complications Trial

This study of 1,441 type 1 patients with diabetes over a period of nine years was completed and reported in September 1993. It conclusively demonstrated that glycemic control is a major deterrent to the development and progression of diabetic microvascular and neuropathic disease.

Diabetes Mellitus

A chronic syndrome of impaired carbohydrate, protein, and fat metabolism owing to insufficient secretion of insulin or to target tissue insulin resistance, characterized by polydipsia, polyuria and polyphagia.

Digital rectal examination

A common screening procedure for prostate cancer, whereby a physician inserts a gloved, lubricated finger into the rectum, in order to feel the size and shape of the prostate through the rectal wall.

Digoxin

A drug commonly used to treat congestive heart failure and certain heartbeat irregularities that is obtained from leaves of the Foxglove (digitalis) plant. Digoxin overdose can be toxic. The level of the drug can be obtained from blood testing, which can aid in setting appropriate dose amounts.

Dilutions

To mix sample with water, saline, or buffer to decrease the concentration.

Direct fluorescent antibody test (DFA)

A test that uses a fluorescent antibody to directly detect an antigen.