A protein that is produced in the liver and gastrointestinal tract of the fetus and by some abnormal tissues in adults.
Alpha-fetoprotein (AFP) can be measured in the maternal blood from the latter part of the 1st trimester of pregnancy, and its concentration rises between the 15th and 20th weeks.
Raised levels of are associated with fetal neural tube defects, such as spina bifida or anencephaly, and certain kidney abnormalities. High levels of also occur in multiple pregnancies (see pregnancy, multiple) and threatened or actual miscarriage. levels may be unusually low if the fetus has Down’s syndrome. For this reason, measurement of blood is included in blood tests, which are used to screen pregnant women for an increased risk of Down’s syndrome.
levels are commonly raised in adults with hepatoma (see liver cancer), cancerous teratoma of the testes or ovaries, or cancer of the pancreas, stomach, or lung.
For this reason, is known as a tumour marker.
(AFP) levels can be used to monitor the results of treatment of certain cancers; increasing levels after surgery or chemotherapy may indicate tumour recurrence.
However, levels are also raised in some noncancerous conditions, including viral and alcoholic hepatitis and cirrhosis.
(AFP) n. a protein that is formed in the liver and yolk sac of the fetus and is present in the fetal serum and secondarily in maternal blood. Maternal AFP is used as a marker in *prenatal screening tests, which can be performed between the 15th and 20th weeks of pregnancy. Levels are elevated in open *neural tube defects (e.g. spina bifida), open abdominal wall defects (e.g. *gastroschisis), fetal death, and multiple pregnancy. Levels of AFP are decreased in *Down’s syndrome. However, AFP levels are affected by the length of gestation and the mother’s weight, and these factors must be considered when interpreting the results. When levels are unexpectedly high or low, further investigations (for example detailed *ultrasonography) are indicated.
Alpha-fetoprotein is also produced by certain tumours, including malignant *teratomas and primary liver tumours (*hepatomas). See tumour marker.
Also called adrenoceptor-blocking agents or alpha blockers, these drugs stop the stimulation of alpha-adrenergic receptors at the nerve endings of the SYMPATHETIC NERVOUS SYSTEM by HORMONES with ADRENALINE-like characteristics. The drugs dilate the arteries, causing a fall in blood pressure, so they are used to treat HYPERTENSION and also benign enlargement of the PROSTATE GLAND. Examples of this group of drugs are doxazosin, indoramin, phentolamine and prazosin. The drugs should be used with caution as some may cause a severe drop in blood pressure when ?rst taken.... alpha adrenergic blockers
A protein produced in the gut and liver of the FETUS. Abnormality in the fetus, such as neural tube defect, may result in raised levels of alphafeto protein in the maternal blood. In DOWN’S (DOWN) SYNDROME, levels may be abnormally low. In either case, screening of the pregnancy should be carried out, including AMNIOCENTESIS to check the amount of alpha-feto protein in the amniotic ?uid. The protein may also be produced in some abnormal tissues in the adult – in patients with liver cancer, for example.... alpha-feto protein
A group of drugs used to treat hypertension (high blood pressure) and urinary symptoms due to enlargement of the prostate gland. Alpha-blockers are also used to treat urinary retention caused by an enlarged prostate gland (see prostate, enlarged). Side effects of the drugs may include dizziness and fatigue due to a sudden drop in blood pressure, nausea, dry mouth, and drowsiness.... alpha-blocker drugs
(alpha-adrenergic blocker) a drug that prevents the stimulation of alpha *adrenoceptors at the nerve endings of the sympathetic nervous system by noradrenaline and adrenaline: it therefore causes relaxation of smooth muscle, including widening of arteries (vasodilatation) and a drop in blood pressure. Alpha blockers include *doxazosin, *phentolamine, *phenoxybenzamine, *indoramin, *prazosin, *alfuzosin, and *tamsulosin.... alpha blocker
any member of a group of *oral hypoglycaemic drugs, including acarbose (Glucobay), used for treating type 2 *diabetes mellitus. They reduce the breakdown and absorption of carbohydrates in the intestine by blocking the action of an important enzyme (?-glucosidase) in this process. Side-effects include flatulence and diarrhoea.... alpha-glucosidase inhibitor
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