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Biomedical subjects

T Chard

Publications and source records attributed to T Chard.

At least 289 records · Page 16Linked to original sources
PubMed1982

Identification of somatostatin in the human placenta.

High pressure liquid chromatography (HPLC), gel chromatography and radioimmunoassay (RIA) were applied to the identification of cyclic somatostatin in human placental tissue. Methanol extracts of the placenta were treated with acetic acid and chloroform, purified on an octadecylsilane column, fractionated on HPLC and gel filtration, and assessed by RIA. It is concluded that human placental somatostatin is similar or identical to cyclic somatostatin on other tissue.

Chromatography, Gel↗
PubMed1981

Sequential fluoroimmunoassay for measurement of pregnancy specific beta 1 glycoprotein using antibody coupled to magnetisable particles.

A direct, sequential fluoroimmunoassay has been developed for the determination of serum levels of pregnancy specific beta 1 glycoprotein (SP1). The method employs rabbit anti-SP1 serum coupled to magnetisable cellulose-iron oxide particles and fluorescein-labelled SP1. Serum samples or standards are incubated with magnetisable solid phase anti-SP1 for 30 min. After magnetic sedimentation of the particles, the supernate, which includes endogenous fluorophores and other interfering factors, is discarded. Fluorescein-labelled SP1 is then added and incubated for a further 45 min; the particles are again sedimented and the fluorescence of the labelled SP1 remaining in the supernate is estimated. This reading related directly to the SP1 content of the original sample. The entire procedure, including fluorometry, is performed within a single disposable polystyrene test tube and is sufficiently simple and reliable for routine application. The sensitivity, specificity and precision is very similar to that of radioimmunoassay, and the results correlate with those of the radioimmunoassay (r = 0.9887).

Female↗
PubMed1981

Circulating concentrations of specific placental proteins (human chorionic gonadotropin, pregnancy-specific beta-1 glycoprotein, and placental protein 5) in untreated gestational trophoblastic tumors.

Serum levels of human chorionic gonadotropin (hCG), pregnancy-specific beta-1-glycoprotein (SP1), and placental protein 5 (PP5) were measured prior to treatment in 14 patient with hydatidiform mole and in nine patients with choriocarcinoma. Measurement of circulating levels of SP1 and PP5, but not hCG, provides a distinction between benign and malignant gestational trophoblastic tumors.

Adult↗
PubMed1981

The pars intermedia and the fetal pituitary-adrenal axis.

The increased production of cortisol by the fetal adrenal gland at term acts as the trigger for parturition in some species. The fetal pituitary controls fetal adrenal function. However, ACTH is only one of a family of closely related peptides which derive from a common precursor and we have shown that although ACTH is the dominant form in the adult pituitary, the expression of the "family trees' is altered in the fetus. In the sheep, it is large-molecular-weight precursors and, in the primate, the smaller peptides such as alpha-MSH, CLIP, beta-MSH and beta-endorphin that predominate in fetal life and which may be responsible for fetal adrenal function. It is still unclear what causes the developmental change in the ACTH "family tree'. Since it may result from a change in pituitary function - from the peptides of the pars intermedia, in the fetus, to those of pars anterior, in the adult - we have studied these two lobes separately in pituitaries taken from adult and fetal sheep and monkeys. Our preliminary results suggest that the change may occur in the neurointermediate lobe in the primate, but that in the sheep the developmental changes occur in the anterior lobe.

Adrenal Glands↗
PubMed1981

Placental protein 5 (PP5) in severe pre-eclampsia and eclampsia.

Circulating methods of placental protein 5 (PP5) were studied in patients with severe preeclampsia and eclampsia. Elevated PP5 levels were frequently observed in the eclampsia group. This elevation may be due to disturbance in endogenous coagulation mechanisms at the placental site.

Eclampsia↗
PubMed1981

Placental protein 5: circulating levels in twin pregnancy and some observations on the analysis of biochemical data from multiple pregnancy.

Blood was collected from 344 subjects with singleton pregnancy between 28 and 40 wk gestation, together with 70 samples from 24 subjects with twin pregnancy of comparable gestation. Circulating placental protein 5 (PP5) in singleton pregnancy rose from a median of 26 microgram/l at 28 wk to reach a plateau with a median of 38 microgram/l at 36 wk. The median PP5 levels in twin pregnancy were 50 microgram/l at 28 wk rising to 65 microgram/l at 38 wk. The ratio of the medians of PP5 levels in twin and singleton pregnancies fell from 1.94 at 28 wk to 1.62 at 38 wk. An "action line' for low levels of PP5 in twin pregnancy was defined by applying a multiple of the median for twin pregnancy.

Analysis of Variance↗
PubMed1981

Chorionic gonadotropin concentration in early human pregnancy: comparison of specific and nonspecific assays.

Daily blood samples were collected during 10 menstrual cycles in which conception had occurred, and changes in circulating concentrations of human chorionic gonadotropin (hCG) were measured simultaneously in specific and nonspecific radioimmunoassays. The hCG concentration profiles were not identical, and the fundamental differences could not be related to differences in technique. Both specific and nonspecific parameters of hCG concentration rose exponentially for the first 2 to 3 weeks following first detection and were thus amenable to linear regression analysis. Doubling times were significantly different at 2.3 and 1.8 days, respectively. Extrapolation of the regression data gave a (theoretical) plasma concentration of 3 IU/liter at 9.5 days after the luteinizing hormone peak using the specific assay but at only 5.5 days using the nonspecific assay. This difference is sufficiently large to suggest the presence of other forms of hCG or its subunits about the time of implantation and during early pregnancy.

Chorionic Gonadotropin↗
PubMed1981

Improved diagnosis of pregnancy-related gynaecological emergencies by rapid human chorionic gonadotrophin beta-subunit assay.

A pregnancy-related disorder was identified by a rapid radioimmunoassay of serum chorionic gonadotrophin (hCG-RIA) in 122 out of 470 women (26 per cent) with lower abdominal pain or bleeding, while a routine pregnancy test in urine was positive in only 7 per cent of these cases. In 49 patients with ectopic pregnancy the rapid hCG-RIA was positive in 90 per cent as compared with 13 per cent for the routine pregnancy test. In patients with evidence of intrauterine pregnancy (66 cases) the rapid hCG-RIA was positive in 98 per cent and the routine pregnancy test in 38 per cent. The clinical sensitivity of the hCG-RIA was 95 per cent, specificity 96 per cent and predictive value 89 per cent. The test can improve the efficiency of the routine diagnosis of early intra- and extrauterine pregnancy-related disorders.

Chorionic Gonadotropin↗
PubMed1981

The effect of protamine on serum levels of placental protein 5 (PP5) in normal and abnormal pregnancy: a possible relation to coagulation abnormalities.

The levels of placental protein 5 (PP5) in pregnancy serum show an apparent increase after the addition of protamine sulphate. The difference of the apparent concentrations of serum PP5 in the presence and absence of protamine (delta PP5) was determined in 345 normal and abnormal pregnancies. A positive delta PP5 was less frequent in diabetic pregnancy (45 per cent) and pre-eclampsia (57 per cent) than in normal pregnancy (80 per cent). These findings provide further evidence that PP5 may be involved in the coagulation system, and in particular may relate to abnormal coagulation processes at the placental site.

Blood Coagulation↗
PubMed1981

Measurement of placental protein 5, placental lactogen and pregnancy-specific beta 1 glycoprotein in mid-trimester as a predictor of outcome of pregnancy.

The circulating levels of placental protein 5 (PP5), placental lactogen (hPL) and pregnancy-specific beta 1-glycoprotein (SP1) were measured in 254 women at the 16th week of pregnancy and the levels were correlated to fetal outcome in late pregnancy. A significant association was shown between high PP5 levels and premature delivery, and low SP1 levels and intrauterine growth retardation. Measurement of placental proteins in the first half of pregnancy may be a valuable clinical index of fetal outcome in late pregnancy.

Adult↗
PubMed1981

Placental protein 5 (PP5) in placental abruption.

The circulating levels of serum placental protein 5 (PP5) were measured in serial samples from 10 subjects who later had placental abruption. PP5 levels were elevated in five immediately prior to the clinical diagnosis of abruption.

Abruptio Placentae↗