| endocardial cushion defect | <radiology> Persistence of primitive atrioventricular canal and anomalies of AV valves associated with: Down syndrome: in 25% of Trisomy 21 an ECD is present; in 45% of ECD Trisomy 21 is present, asplenia/polysplenia types: complete (AV canal), partial findings: gooseneck deformity on angiogram, increased pulmonary vascularity, enlarged pulmonary artery, enlarged RV, LV, RA; normal LA (secondary to atrial septal defect) (12 Dec 1998) |
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| 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) |
| 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) |
| genetic | <biology> Pertaining to reproduction or to birth or origin. (07 May 1998) |
| genetic amplification | A process for producing an increase in pertinent genetic material, particularly for increasing the proportion of plasmid DNA to that of bacterial DNA. Includes the production of extrachromosomal copies of the genes for RNA. (05 Mar 2000) |
| genetic assimilation | <genetics> A situation in which a characteristic that is normally expressed only in certain environmental situations becomes fixed in a population so that it no longer requires environmental factors to be expressed. (07 May 1998) |
| genetic association | The occurrence together in a population, more often than can be readily explained by chance, of two or more traits of which at least one is known to be genetic. (05 Mar 2000) |
| genetic block | <biochemistry, molecular biology> An obstruction in a biochemical pathway caused by a mutation that has crippled production of an enzyme critical to the pathway. (07 May 1998) |
| genetic burden | The genetic debt due to harmful mutation but as yet undischarged. (In a large population of fixed size every mutation with diminished genetic fitness will eventually become extinct and depending on the details of inheritance and phenotype must be paid for by a fixed number of genetic deaths per mutation, the genetic debt.) (05 Mar 2000) |
| genetic carrier | An unaffected heterozygote bearing a usually harmful recessive gene, a cancer that bears a dominant but latent age-dependent trait to have offspring with unbalanced karyotypes. (05 Mar 2000) |