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Biomedical subjects

K Shrimanker

Publications and source records attributed to K Shrimanker.

17 recordsLinked to original sources
PubMed1994

Serum PAPP-A and free beta-hCG are first-trimester screening markers for Down syndrome.

Serum measurements of pregnancy-associated plasma protein A (PAPP-A) and the free beta-human chorionic gonadotrophin (hCG) subunit were made in 13 women with Down syndrome (DS) pregnancies and six other women with fetal aneuploidy ascertained at chorionic villus sampling (CVS), as well as 89 women with contemporaneous normal control pregnancies. Median serum PAPP-A measurements (0.31 MOM, 95 per cent confidence interval (CI) 0.22-0.65 vs. normal 1.06, 95 per cent CI 0.89-1.20) were lower and free beta-hCG subunit measurements (1.13 MOM, 95 per cent CI 0.93-2.63 vs. normal 0.91, 95 per cent CI 0.79-1.03) were higher at statistically significant levels. Receiver operator characteristics (ROC) curves showed that the highest sensitivity for detection, 71.2 per cent (95 per cent CI 54.7-87.6 per cent), was for depressed PAPP-A levels; the combination of low serum PAPP-A levels, maternal age, and elevated free beta-hCG levels yielded a detection rate of 78.9 per cent (95 per cent CI 64.9-92.8 per cent) of the affected pregnancies at 8-12 weeks' gestation.

Adult↗
PubMed1985

Binding of steroid hormones and anabolic agents to bovine sex-hormone binding globulin.

Binding of some selected steroids and anabolic agents to bovine sex-hormone binding globulin (SHBG) was investigated. SHBG binding affinities, relative to the reference hormone 5 alpha-dihydrotestosterone, were estimated for the compounds. The results demonstrate that binding of steroid hormones to SHBG is facilitated by the 17 beta-hydroxyl group, possibly involving hydrogen binding, and by the methyl group at C-19 of the steroid moiety. Structural modifications at C-17 of a steroid molecule involving esterification, epimerization or reduction of the 17 beta-hydroxyl group, or introduction of a bulky 17 alpha group have the effect of decreasing the SHBG binding affinity of the steroid molecule.

Androstenedione↗
PubMed1982

Transfer of contraceptive steroids in milk of women using long-acting gestagens.

Levels of norethisterone and medroxyprogesterone acetate were measured in serum and milk of women receiving the injectable contraceptive formulations Norigest and DepoProvera, respectively, throughout complete injection intervals. In 5 of 10 women receiving Norigest, serum norethisterone levels were undetectable by 8 weeks after injection and only 2 women had detectable levels of norethisterone in milk at this time. In contrast, 8 of 10 women receiving DepoProvera had detectable levels of medroxyprogesterone acetate in both serum and milk 12 weeks after injection. The ratio of the milk:serum concentrations of norethisterone varied from 0.12 to 0.92 (mean 0.34) and for medroxyprogesterone acetate from 0.12 to 2.60 (mean 0.88). It is unlikely that these differences between the two formulations are due entirely to differences between the binding of norethisterone and medroxyprogesterone acetate to serum proteins. The area under the curve of serum steroid concentrations plotted against time was only 50% higher for women injected with DepoPovera than for those injected with Norigest but the area under the curve for milk values was 400 times higher. Assuming the infant ingests 600 ml daily, the daily intake of steroids in the first week after injection would be 0.5 to 2.4 micrograms for norethisterone and 1 to 13 micrograms for medroxyprogesterone acetate. By 8 weeks after injection, the amount of norethisterone ingested would be small but that of medroxyprogesterone acetate would still be significant.

Adult↗
PubMed1980

Bioavailability of Lynestrenol.

The bioavailability of lynestrenol and ethynyloestradiol from a capsule formulation was superior to a normal tablet formulation. Bioavailability, as measured by the area under the plasma concentration curves, showed, particularly in the case of the capsule formulation, that all of the administered lynestrenol was converted to norethisterone.

Adult↗
PubMed1979

Blood levels of medroxyprogesterone acetate after multiple injections of depoprovera or cycloprovera.

Mean levels of MPA in blood taken 90 days after injection were not significantly different between women who had received a single injection of DepoPrevera and those who had received eight injections at 90-day intervals. There was a wide variation in plasma MPA concentration in the two groups of women. In women who had received 31 to 45 injections of CycloProvera, plasma levels of MPA 28 days after injection were significantly higher than those of women who had received a single injection. The levels were also higher than those found in women 90 days after injection of DepoProvera. The results suggest that the dose of MPA in CycloProvera could be reduced.

Female↗
PubMed1979

Rate of metabolism of norethisterone in women from different populations.

The rate of metabolism of orally administered norethisterone was compared in fourteen centres by measuring plasma levels of the steroid by radioimmunoassay at varying times after oral administration of a 1 mg dose. The inter-centre differences were of the same order as the intra-centre differences. Variations in metabolism appeared not to be due to variations in body size.

Adult↗
PubMed1978

Occurrence of ovulation in women receiving the injectable contraceptive norethisterone oenanthate.

Ovarian function was studied in ten women receiving a single intramuscular injection of 200 mg norethisterone oenanthate. Two of the ten women appeared to ovulate within 60 days of injection and a further four within 90 days. Follicular activity probably not followed by ovulation occurred in five subjects within 60 days of the injection and in a further subject within 90 days. Only one subject showed no evidence of follicular or luteal activity during the course of this study. There was wide variation in the rate at which the administered gestagen was metabolised and no correlation between the rate of metabolism of norethisterone and the return of ovarian function or the ponderal index, height or weight of the subjects.

Adult↗