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Biomedical subjects

K Buckshee

Publications and source records attributed to K Buckshee.

At least 91 records · Page 5Linked to original sources
PubMed1978

Interaction of progestins with steroid receptors in human uterus.

Norethindrone (17beta-hydroxy-19-nor-17alpha-pregn-4-en-20-yn-3-one) and norethindrone acetate (17beta-acetoxy-19-nor-17alpha-pregn-4-en-20-yn-3-one) interfered to a varying degree, by competitive inhibition, with the binding of progesterone and oestradiol to respective cytoplasmic receptors in the human uterus. Progesterone binding to 4S macromolecule was saturable and co-specific for progestins. Competitors like norgestrel (17beta-hydroxy-18-methyl-19-nor-17alpha-pregn-4-en-20-yn-3-one), 19-norprogesterone, medroxyprogesterone acetate (17alpha-acetoxy-6alpha-methylpregn-4-ene-3,20-dione) and compound R(5020) (17,21-dimethyl-19-norpregna-4,9-diene-3,20-dione) possessed higher binding affinities for the progestin receptor. The dissociation constant (K(d)) for the progesterone-receptor interaction was 0.6-1.6nm and the receptor concentration ranged between 6600 and 8200 sites/cell. Norethindrone and norethindrone acetate competed for the progesterone receptor with inhibition constants (K(i)) of 6.8 and 72nm respectively. Gradient displacement and competitive-receptor assays indicated that norethindrone acetate-binding affinity for progestin receptor was approximately one-tenth that of norethindrone and progesterone. The progestins also inhibited oestradiol binding to 4.6S oestrogenic receptor by 8-12%, involving interaction at the oestradiol-binding site with a calculated K(i) value of 0.5-0.8mum. The competitive interaction of progestins with steroid receptors may be of putative importance in explaining the progestin action at the target site.

Acetates↗
PubMed1976

Disappearance of (14,15-3H)d,1-norgestrel from plasma and its distribution in the reproductive tract of women.

After an iv injection of [14,15-3H]d,1-norgestrel into 7 women, its disappearance from the plasma and its distribution in the reproductive organs has been investigated. It was found that initially norgestrel disappeared rapidly from the plasma with a half-life of 38.8 min followed by a slower disappearance with a half-life of 45.18 h. The disappearance curve has been analysed on the basis of a biexponential curve representing a two compartmental model. The low metabolic clearance rate of 458.5 1/24 h indicated a more prolonged persistance of norgestrel in the body. Uptake of norgestrel and its metabolites was very high in the endometrium, myometrium, cervix. Fallopian tube, ovary and body fat. Compared to the myometrium, more norgestrel as such was concentrated in the endometrium at 30 min and 12 h after injection of [14,15-3H]d,1-norgestrel. The myometrium on the other hand contained higher amounts of norgestrel at 5 min. The significance and the possible role of localization of norgestrel at multiple sites in the reproductive tract and its contraceptive action are discussed.

Adipose Tissue↗
PubMedDate not supplied

Ultrasonographic fetal nomograms of anterior ventricular hemisphere ratio (AVHR) and posterior ventricular hemisphere ratio (PVHR) for early prenatal diagnosis of hydrocephalus.

Serial ultrasound scans were done in 150 fetuses between 14th to 22nd week of gestation to establish the nomograms of anterior ventricular hemisphere ratio (AVHR) and posterior ventricular hemisphere ratio (PVHR). Of 150 fetuses, 100 were in the high risk group for neural tube defect and 50 were in the control group. The study indicates that the value of AVHR decreases from 0.62 to 0.50 and PVHR from 0.60 to 0.50 between 14th to 22nd week of gestation. No statistical difference was observed in the values of AVHR and PVHR in high risk and low risk (control) cases (p > .001). The value of AVHR or PVHR greater than 0.5 after 18 weeks of gestation or more was considered pathological for hydrocephalus. In 2, out of 3 cases of hydrocephalus detected in our series, the value of AVHR and PVHR was 0.7 at 20 weeks and in the third case it was 0.6 at 18 weeks. All of these values were 3 SD above the normal for the period of gestation.

Cephalometry↗