| aflatoxin B1 hydroxylase | <enzyme> Hydroxylases may be replaced by mixed function oxidases as appropriate Registry number: EC 1.14.- Synonym: aflatoxin b1 4-hydroxylase (26 Jun 1999) |
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| aflatoxin B1 reductase | <enzyme> Reduces the cyclopentenone ring of aflatoxin b1 to aflatoxicol; requires NADPH as cofactor Registry number: EC 1.1.1.- (26 Jun 1999) |
| aflatoxin G2a reductase | <enzyme> Has broad substrate specificity in cell-free extracts from aspergillus parasiticus; versicolorin a hemiacetal is reduced to versicolorin c; 17-hydroxy-16,17-dihydrosterigmatocystin is reduced to a 14,17-hydrated derivative; aflatoxin g2a is converted to a 13,16-hydrated derivative of afg2 Registry number: EC 1.1.1.- (26 Jun 1999) |
| aflatoxin m1 | <chemical> Highly toxic 4-hydroxylated metabolite of aflatoxin b1 found in the milk of cows fed toxic meal. It has mutagenic, carcinogenic, and teratogenic activity. It is formed by the enzymatic hydroxylation of aflatoxin b1 by aflatoxin b1 4-hydroxylase, a cytochrome p-450-dependent enzyme. Pharmacological action: carcinogens, mutagens, teratogens. Chemical name: Cyclopenta(c)furo(3',2':4,5)furo(2,3-h)(1)benzopyran-1,11-dione, 2,3,6a,9a-tetrahydro-9a-hydroxy-4-methoxy-, (6aR-cis)- (27 Jun 1999) |
| AFLP | <technique> Invented by KeyGene, a Dutch biotech company based in Wageningen, Holland. The technique is now merchandised under licence agreement by Perkin Elmer. Selected markers are amplified in a PCR, which makes amplified fragment length polymorphism an easy and fast tool for strain identification in agriculture, botany, microbiology and animal breeding. Acronym: AFLP (05 Feb 1998) |
| AFO | A brace (usually plastic) worn on the lower leg and foot to support the ankle, hold the foot and ankle in the correct position, and correct foot drop. (12 Dec 1998) |
| AFORMED phenomenon | As induced pulsus alternans progresses, a state in which alternating heart depolarisations fail to eject any blood, thus allowing longer diastolic filling; the subsequent beat is then able to produce a significant ejection; at high rates the cardiac minute volume and blood pressure may appear normal. Origin: Alternating, failure of response, mechanical, to electrical depolarisation (05 Mar 2000) |
| AFP | <protein, tumour marker> A protein substance that is normally produced by the liver cells. It is one of the first alpha-globulins to appear in mammalian sera during development of the embryo and the dominant serum proteins in early embryonic life. They reappear in the adult serum during certain pathologic states. Measurement of the alpha-fetoprotein level in the bloodstream has been used as a early detection test for some forms of cancer (hepatocellular carcinoma). Alpha-fetoprotein can also be an important marker in the fluid obtained by amniocentesis for the prenatal diagnosis of anencephaly and other open neural tube defects such as spina bifida. Elevated in: wrong dates for a pregnancy, multiple gestation, midline closure (neural-tube) defects, encephalocele, anencephaly, liver tumours, hepatoblastoma, haemangioendothelioma (occasionally, mild), hepatocellular carcinoma (HCC, hepatoma). The level produced by liver tumours (hepatomas), germ cell tumours (teratocarcinoma and embryonal cell carcinomas) permits the monitoring of response to treatment of these tumours. Decreased in: wrong dates for a pregnancy, chromosome abnormality (including Down syndrome) Acronym: AFP (27 Jun 1999) |
| africa south of the sahara | All of africa except northern africa (africa, northern). (12 Dec 1998) |
| africa, eastern | The geographical area of africa comprising burundi, djibouti, ethiopia, kenya, rwanda, somalia, sudan, tanzania, and uganda. (12 Dec 1998) |
| africa, northern | The geographical area of africa comprising algeria, egypt, libya, morocco, and tunisia. It includes also the vast deserts and oases of the sahara. It is often referred to as north africa, french-speaking africa, or the magreb. (12 Dec 1998) |
| africa, southern | The geographical area of africa comprising angola, botswana, lesotho, malawi, mozambique, namibia, south africa, swaziland, zambia, and zimbabwe. It includes what was formerly called south-west africa or german southwest africa but it was terminated in 1966 by a united nations resolution. (12 Dec 1998) |
| africa, western | The geographical area of africa comprising benin, burkina faso, cote d'ivoire, gambia, ghana, guinea, guinea-bissau, liberia, mali, mauritania, niger, nigeria, senegal, sierra leone, and togo. (12 Dec 1998) |
| african | Of or pertaining to Africa. African hemp, a fibre prerared from the leaves of the Sanseviera Guineensis, a plant found in Africa and India. African marigold, a tropical American plant (Tagetes erecta). African oak or African teak, a timber furnished by Oldfieldia Africana, used in ship building. Origin: L. Africus, Africanus, fr. Afer African. Source: Websters Dictionary (01 Mar 1998) |
| African endomyocardial fibrosis | Fibrosis of the inner layers of the myocardium, often including the endocardium, causing diastolic restriction of the heart; indigenous to East Africa. (05 Mar 2000) |