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Biomedical subjects

T Chard

Publications and source records attributed to T Chard.

At least 343 records · Page 19Linked to original sources
PubMed1979

Development of a radioimmunoassay for adrenal specific protein: its measurement in biological fluids and tissues.

A radioimmunoassay for a new human adrenal specific protein (ASP) is described. The assay has a lower limit of detection of approximately 50 micrograms/l. The ASP extracted and purified from adrenal glands was used for standardization, radio-iodination and immunization of rabbits. Adrenal specific protein can be detected in normal human serum and plasma (240 +/- 80 and 190 +/- 60 micrograms/ml (means +/- S.D.) respectively), tissue levels were found in extracts of adrenal medulla, with appreciable amounts in the adrenal cortex, pituitary gland, seminal vesicle and testis, and low levels in all other tissues examined. The highest concentrations in biological fluids were found in seminal plasma and to a lesser extent in milk and menstrual fluid.

Adrenal Glands↗
PubMed1979

Fluoroimmunoassay for human choriomammotropin.

We describe an immunoassay for human choriomammo-tropin by use of the fluorescein-labeled hormone (of human origin). The technique is generally similar to the radioimmunoassay for this material, but has the advantage of stability of tracer and avoidance of radiation hazard. However, the procedure requires approximately 50-fold more tracer than does the radioimmunoassay, and this would be a disadvantage with materials for which supplies of purified antigen are scarce. Furthermore, both within-assay variation (3.9%) and between-assay variation (7.8--7.9%) were less satisfactory than that of radioimmunoassay (1.5% and 2.2--3%, respectively). This is almost certainly the result of imprecision of end-point detection and could probably be corrected by further attention to equipment design.

Female↗
PubMed1978

A simple and reliable method for the purification of human alphafetoprotein (AFP) from amniotic fluid and fetal livers.

Highly purified human alphafetoprotein has been isolated from amniotic fluid and fetal livers by a combination of salting-out, and gel filtration, ion exchange, and concanavalin-A affinity chromatography. They yield ranged from 25 to 37%, and purity was demonstrated by radioimmunodiffusion, crossed radioimmunoelectrophoresis, polyacrylamide gel electrophoresis, and comparison with other preparations by radioimmunoassay. Immunochemical potency by weight of alphafetoprotein purified from amniotic fluid was similar to that from fetal liver, with molecular weights of 70 000 and 68 500 respectively. The amino acid and carbohydrate composition is also reported. This physicochemical method is relatively simple and inexpensive and is well suited for large scale production.

Amniotic Fluid↗
PubMed1978

Fetal wastage as a result of an alpha-fetoprotein screening programme.

Amniocentesis was performed in 102 pregnancies in which maternal serum-alpha-fetoprotein (A.F.P.) concentrations were raised. 18 pregnancies were terminated. There were 15 neural-tube defects, 2 gastrointestinal abnormalities (1 of which could have been corrected by surgery), and 1 case of hydrocephaly. There was an association between raised maternal serum-A.F.P. and complications of late pregnancy including premature labour, perinatal death, and severe pre-eclampsia. After amniocentesis there was spontaneous abortion of 3 normal fetuses and 1 abnormal fetus.

Abortion, Spontaneous↗
PubMed1978

The significance of raised maternal plasma alpha-fetoprotein in twin pregnancy.

A hundred twin pregnancies were examined before 27 weeks gestation. The level of maternal plasma alpha-fetoprotein (AFP) was correlated with outcome of the pregnancy. Forty per cent of all women had elevated plasma AFP levels. At birth the combined infant weights were greater in the women with elevated AFP; the gestational age at delivery was unrelated to the level of AFP in early pregnancy.

Birth Weight↗
PubMed1978

Pregnancy specific beta1 glycoprotein in fetal and maternal compartments.

Pregnancy specific beta glycoprotein is produced by the syncytiotrophoblast and secreted into the maternal peripheral circulation reaching levels of approximately 200 m/liter in normal pregnancy at term. In the present study the distribution of this newly defined placental protein was examined in maternal and fetal compartments in 12 patients at delivery.

Amniotic Fluid↗
PubMed1977

Concentrations of pregnancy-specific beta 1-glycoprotein in maternal blood in normal pregnancy and in intrauterine growth retardation.

A radioimmunoassay has been developed for pregnancy-specific beta 1-glycoprotein (S.P.1), a product of the human placenta. Circulating concentrations of S.P.1 were measured in 153 women in the third trimester of normal pregnancy and in 27 women who delivered children with birth-weight below the 10th centile of the normal range--i.e., with intrauterine growth regardation (I.U.G.R.). Concentrations of S.P.1 showed a skewed distribution and rose progressively to reach a plateau in the last four weeks of pregnancy. In over 70% of women with I.U.G.R. of the fetus, concentrations of S.P.1 were low. Measurement of serum-S.P.1 may provide a new index of fetal wellbeing.

Birth Weight↗
PubMed1977

Specific and sensitive determination of pregnancy-specific beta 1-glycoprotein by radioimmunoassay. A new pregnancy test.

A specific and highly sensitive radioimmunoassay (R.I.A.) for determination of pregnancy-specific beta 1-glycoprotein (S.P.1) in human plasma, urine, amniotic fluid, and breast milk has been developed. The minimum detection limit of S.P.1 was 8 mug/1 of sample. The assay was applied to plasma and/or urine samples from 8 women in early pregnancy. S.P. 1 was detected in the plasma of all three women obtained within 14 days of ovulation, the earliest positive result being at 7 days. In another woman plasma was negative at day 18 and positive by day 22. In the three remaining women plasma S.P.1 was detected when measured within 24 to 36 days of ovulation. S.P.1 was detected in four urine samples obtained between 20 and 28 days after ovulation. S.P.1 was also measured in breast milk, amniotic fluid, cord blood, and plasma of women with ectopic gestation and trophoblastic disease. It is suggested that the assay of S.P.1 may have important advantages over existing systems for detection and monitoring of early pregnancy.

Amniotic Fluid↗
PubMed1977

Circulating levels of pregnancy-specific beta1-glycoprotein in early pregnancy.

Circulating levels of pregnancy-specific beta1-glycoprotein (SP1 or PSbetaG), luteinizing hormone (LH) and human chorionic gonadotrophin (HCG) were measured serially in 9 subjects immediately after conception. Ovulation occurred spontaneously in 3 subjects, or followed administration of clomiphene citrate (2 subjects) or bromocriptine (4 subjects). The timing of ovulation was determined by the appearance of the LH surge. Levels of HCG were detected 10 to 16 days, and SP1, 18 to 23 days after ovulation. These findings suggest that the measurement of plasma levels of SP1 may provide valuable additional biochemical evidence of pregnancy.

Chorionic Gonadotropin↗