| enzyme defect | A disorder resulting from a deficiency (or functional abnormality) of an enzyme. In 1902 Archibald Garrod first attributed a disease to an enzyme defect: an inborn error of metabolism. Today, newborns are routinely screened for certain enzyme defects such as PKU (phenylketonuria) and galactosaemia, an error in the handling (metabolism) of the sugar galactose. (12 Dec 1998) |
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| fibrous cortical defect | A common 1 to 3 cm defect in the cortex of a bone, most commonly the lower femoral shaft of a child, filled with fibrous tissue. Nonosteogenic or nonossifying fibroma by convention refers to lesions greater than 3 cm in diameter. See: nonossifying fibroma. Synonym: nonosteogenic fibroma. (05 Mar 2000) |
| uterine filling defect | <radiology> Technical, bubble, blood clot, mucoid material, congenital fold, pseudoadhesions / ridging -- folds long axis, neoplasm, submucosal leiomyoma, adenoma, endometrial carcinoma, pregnancy-related, pregnancy, molar pregnancy, retained conceptus, polyp, septated uterus, synechiae, IUD, iatrogenic (post-op) (12 Dec 1998) |
| filling defect | Displacement of contrast medium by a space-occupying lesion in a radiographic study of a contrast-filled hollow viscus, such as a polyp on a barium enema; also applied to defects in the otherwise uniform distribution of radionuclide in an organ, such as a metastasis in the liver on a 99mTc-sulfur colloid scan. (05 Mar 2000) |
| filling defect in renal collecting system | <radiology> Common causes: transitional cell carcinoma, blood clot, lucent calculus (urate) less common causes: fungus ball, sloughed papilla, fibroepithelial polyp, invasion by hypernephroma, malakoplakia, vessel impression, metastases (12 Dec 1998) |
| lambdoid suture defect | <radiology> Well-defined lucent lesion, classically unilateral, associated with neurofibromatosis (12 Dec 1998) |
| luteal phase defect | Inadequate function of the corpus luteum that may prevent a fertilized egg from implanting in the uterus or may lead to early pregnancy loss. (09 Oct 1997) |
| adrenal mass | <radiology> Metastasis, most common (especially lung, melanoma), primary adenocarcinoma, large at diagnosis (greater than 5 cm), usually functional (increased corticosteroids most likely to be Cushing's), rapid growth, benign adrenal adenoma, with or without functional, nonfunctional occurs in 2-8% of population, diff from metastasis: MRI (metastasis bright on T2), biopsy, follow, pheochromocytoma, neuroblastoma, myelolipoma, cyst / pseudocyst see also: adrenal calcification, haemorrhage (12 Dec 1998) |
| apperceptive mass | The already existing knowledge base in a similar or related area with which the new perceptual material is articulated. (05 Mar 2000) |
| atomic mass | <chemistry, physics> The mass of an atom relative to other atoms. The present-day basis of the scale of atomic weights is carbon, the most common isotope of this element has arbitrarily been assigned an atomic weight of 12. The unit of the scale is 1/12 the weight of the carbon atom or roughly the mass of one proton or one neutron. The atomic weight of any element is approximately equal to the total number of protons and neutrons in is nucleus (16 Dec 1997) |
| atomic mass unit | <chemistry> One-twelfth the mass of a neutral atom of the most abundant isotope of carbon. (16 Dec 1997) |
| bilateral adrenal mass | <radiology> Acute granulomatous disease (e.g., TB), metastases (bilateral in 15%), pheochromocytoma (bilateral in 10%), adrenal hyperplasia (adenoma), spontaneous adrenal haemorrhage (12 Dec 1998) |
| body mass index | One of the anthropometric measures of body mass; it has the highest correlation with skinfold thickness or body density. (12 Dec 1998) |
| breast mass | <oncology, surgery> A breast lump may be benign or cancerous. Examples of breast lumps include: breast abscess, fat necrosis, fibroadenoma, fibrocystic breast disease and breast cancer. A breast biopsy is the best way to determine the aetiology of a breast lump. Remember, 80 to 85% of all biopsies are benign. (27 Sep 1997) |
| para-sellar mass | <radiology> Mnemonic: SATCHMO, S sphenoid sinus tumour, A aneurysm / adenoma of pituitary, T teratoid lesion, C craniopharyngioma, H hypothalamic glioma / histiocytoma, M meningioma / metastasis, O optic glioma less common lesions: germinoma, epidermoid, hamartoma, chordoma, arachnoid cyst (12 Dec 1998) |