Graphite - Group

graphite

(graf′īt″) [grapho- + -ite] One of the allotropes of carbon. It has been used as a dry lubricant and as an erasable lead in pencils. SEE: carbon.

grapho-, graph-

[Gr. graphos, something written] Prefix meaning writing.

graphology

(graf-ol′ŏ-jē) [grapho- + -logy] The examination of handwriting, used to diagnose or analyze personality.

-graphy

[Gr. -graphia fr. graphein, to write] Suffix meaning process or form of writing or recording.

GRAS

generally recognized as safe.

grasp

(grasp) Holding or clasping objects with the fingers, the palm, or both.

grasper

(grăsp′ĕr) A device used to grab and hold tissue, e.g., during laparoscopic surgery.

grating

(grāt′ing) In spectrophotometry, the element used in a monochromator that disperses white light into the visible spectrum. It is composed of finely etched lines in the reflecting material.

grave

[L. gravis, heavy] Serious; dangerous; severe.

gravel

(grăv′ĭl) [Fr. gravelle, coarse sand] Crystalline dust or concretions of crystals from the kidneys; generally made up of phosphates, calcium, oxalate, and uric acid.

Graves, Robert James

(grāvz) Robert James Graves, Irish physician, 1796–1853.

 G. disease Hyperthyroidism caused by an autoimmune destruction of the thyroid gland.

 INCIDENCE: Four or five people out of 10,000 develop Graves disease, making it the most common cause of hyperthyroidism. The disease is 10 times more common in women than in men. Most patients are under the age of 40.

 CAUSES: The hyperthyroidism of Graves disease is caused by stimulation of thyroid cells by an autoantibody that binds to and activates the thyroid-stimulating hormone (TSH) receptor. Receptor binding causes cells in the thyroid to produce excessive amounts of thyroid hormone. There is a genetic predisposition to the disease, an increase in likelihood of Graves disease during pregnancy, and an increased risk in smokers.

 SYMPTOMS AND SIGNS: The disease typically increases thyroxine (T₄) production, produces enlargement of the thyroid gland, and also may cause ocular findings (proptosis, lid lag, and stare). Other findings include palpitations, nervousness, intolerance of heat, sweating, frequent defecation, insomnia, menstrual irregularities, tremor, and weight loss despite increased appetite.

 DIAGNOSIS: The clinical finding of goiter, proptosis, and elevated levels of thyroxine with suppressed TSH are diagnostic of Graves disease because no other cause of hyperthyroidism affects the periocular tissues. When exophthalmos or other ocular findings are not present, the disease can be diagnosed with ...