| neural tube defect | <neurology, paediatrics> Abnormal development during embryonic life of the neural tube producing congenital malformations of the nervous system due to closure failure of the neural tube. The structure gives rise to the central nervous system (the brain and spinal cord), and failure to close results in anencephaly (absence of the cranial vault and absence of most or all of the cerebral hemispheres of the brain) and spina bifida or meningomyelocele (open spina with exposure and protusion of the spinal cord). The risk of neuroal tube defects can be decreased by the mother taking folic acid during pregnancy. (04 Jul 1999) |
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| defect | 1. Want or absence of something necessary for completeness or perfection; deficiency; opposed to superfluity. "Errors have been corrected, and defects supplied." (Davies) 2. Failing; fault; imperfection, whether physical or moral; blemish; as, a defect in the ear or eye; a defect in timber or iron; a defect of memory or judgment. "Trust not yourself; but, your defects to know, Make use of every friend any every foe." (Pope) "Among boys little tenderness is shown to personal defects." (Macaulay) Synonym: Deficiency, imperfection, blemish. See Fault. Origin: L. Defectus, fr. Deficere, defectum, to desert, fail, be wanting; de- + facere = to make, do. See Fact, Feat, and cf. Deficit. Source: Websters Dictionary (01 Mar 1998) |
| defect, atrial septal | A hole in the septum, the wall, between the atria, the upper chambers of the heart. Commonly called an ASD. ASDs are a major class of congenital cardiac malformation. (12 Dec 1998) |
| defect, enzyme | An abnormality in the protein (enzyme) important in catalyzing a normal biochemical reaction in the body. Disorders result from a deficiency (or functional abnormality) of an enzyme. Archibald Garrod in 1902 was the first to attribute a disease to an enzyme defect: an inborn error of metabolism. Today, newborns are routinely screened for certain enzyme defects such as phenylketonuria (PKU) and galactosaemia, an error in the handling (metabolism) of the sugar galactose. (12 Dec 1998) |
| defect, ventricular septal | Hole in the interventricular septum, the wall between the ventricles (lower chambers of the heart). Commonly called a VSD. VSDs are a common class of heart deformity present at birth (congenital cardiac malformation). (17 Dec 1998) |
| iodide transport defect | See: familial goiter. (05 Mar 2000) |
| iodotyrosine deiodinase defect | See: familial goiter. (05 Mar 2000) |
| oesophageal filling defect | <radiology> Tumour, carcinoma (oesophagus, stomach extending proximally), leiomyoma / leiomyosarcoma, polyp: fibrovascular, inflammatory, adenomatous, papilloma, carcinosarcoma, lymphoma, metastasis, oesophageal varix, extrinsic lesion (vascular impression, adenopathy, cyst), foreign body (12 Dec 1998) |
| osteoporotic marrow defect | Focal osteoporotic bone marrow defect of the jaw; a focal radiolucent defect composed of normal marrow. (05 Mar 2000) |
| Eisenmenger's defect | The combination of ventricular septal defect with pulmonary hypertension and consequent right-to-left shunt through the defect, with or without an associated overriding aorta. Synonym: Eisenmenger's defect, Eisenmenger's disease, Eisenmenger's tetralogy. (05 Mar 2000) |
| 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) |
| 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) |