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Biomedical subjects

B B Saxena

Publications and source records attributed to B B Saxena.

At least 55 records · Page 3Linked to original sources
PubMed1980

Delayed puberty in males with chronic renal failure.

The effects of chronic renal failure on the pituitary-testicular axis of 31 males, aged 11.7 to 20.0 yr (mean, 16.0 yr) were studied. Nine patients not on hemodialysis (group I) had serum creatinines between 2.5 and 8.0 mg/dl, 10 patients were on hemodialysis (group II) and 12 patients had received a renal transplant (group III). The Tanner stage of pubertal development was delayed relative to chronologic age. Testosterone (T), delta 4-androstenedione (delta 4), and urinary 17-keto steroids were normal when related to pubertal stage in groups I and II; and dehydroepiandrosterone (DHEA) and DHEA sulfate (DS) were in the low normal range. In group III, adrenal androgens (delta 4, DHEA, DS) were decreased as a consequence of prednisone therapy whereas T was normal. Luteinizing hormone levels were normal in all. Follicle-stimulating hormone levels were normal in all. Follicle-stimulating hormone (FSH) was significantly increased in groups I and II. In group III, FSH was normal in 6 of 9 patients with serum creatinine concentrations < 2 mg/dl. FSH levels were uniformly elevated in Tanner I-V patients with creatinines > 2 mg/dl. The data shows that FSH is elevated in patients with chronic renal failure even in prepuberty and early adolescence. This may reflect damage to germinal epithelium prior to the advent of spermatogenesis, whereas Leydig cell function appears to remain intact.

Adolescent↗
PubMed1980

A rapid, centrifugation-free radioimmunoassay specific for human chorionic gonadotropin using glass beads as solid phase.

A simple, specific, rapid, centrifugation-free solid phase RIA for hCG has been developed. Purified gamma-globulin isolated from antisera produced against hCG-beta in rabbits is covalently linked to glutaraldehyde-activated aminopropyl glass beads. The entire assay can be completed within 3 h at room temperature. The sensitivity (1 ng/ml), precision (intra- and interassay variabilities, less than 10% and less than 15%, respectively), and specificity (0.4% cross-reactivity with LH) are comparable to other methods. The hCG levels determined by the present method show good correlation with those obtained by another RIA and by radioreceptorassay. The present method also provides the basis for the development of similar rapid and sensitive assays of other hormones.

Chorionic Gonadotropin↗
PubMed1979

Studies on modification of tryptophan, methionine, tyrosine and arginine residues of human follicle-stimulating hormone and its subunits.

Based on the regeneration of the hormonal activity following recombination, the alpha and beta subunits of human follicle-stimulating hormone have been designated as 'functional' or 'nonfunctional'. Chemical modifications of the tryptophan, methionine, tyrosine and arginine residues of human follicle-stimulating hormone, luteinizing hormone, and the 'functional' human follicle-stimulating hormone alpha and beta subunits have indicated that the tryptophan in human follicle-stimulating hormone-beta and human luteinizing hormone-beta is essential for the biological activity. The iodination of human follicle-stimulating hormone-alpha did not interfere with the hormonal activity. The modification of arginine abolishes the biological activity of the hormones. The accessibility of tyrosine and methionine in human follicle-stimulating hormone-alpha, of arginine in both native hormones and subunits, and the non-availability of the tryptophan residues to 2-hydroxy 5-nitrobenzyl bromide suggest that the alpha subunit lies on the surface of the native molecule.

Amino Acid Sequence↗
PubMed1979

Gonadotropin-like substance in the preimplanted rabbit blastocyst.

The presence of a gonadotropin-like substance in preimplanted rabbit blastocyst fluid was determined bu radioreceptorassay of human chorionic gonadotropin (hCG)/luteinizing hormone (LH), using receptors prepared from bovine corpus luteum, rat testis, and rat ovaries. An average of 16.6 microliter of fluid containing 0.83 ng of luteotropic material was recovered from each blastocyst. An intense fluorescence was exhibited by the trophoblastic cells of the blastocysts treated with fluorescein-conjugated gamma-globulin isolated from antiserum raised against human chorionic gonadotropin. Serum concentrations of LH as well as estradiol, progesterone, and 17 alpha-hydroxyprogesterone up to day 6 after mating were determined in pregnant rabbits and compared with those in pseudopregnant and normal rabbits. In pregnant rabbits after mating, a surge of 62 +/- 15 ng of luteinizing hormone and 73 +/- 22 ng of progesterone/ml of serum occurred which returned to basal levels at 6 hours and on day 1, respectively. Secondary increases in serum luteinizing hormone of 26 +/- 12 to 36 +/- 16 ng/ml on days 3 and 5 and in serum progesterone of 16 +/- 4 and 14 +/- 5 ng/ml on days 5 and 6, respectively, were observed in pregnant rabbits.

Animals↗
PubMed1978

Isolation and amino acid sequence of the alpha-subunit of follicle-stimulating hormone from equine pituitary glands.

Six hundred milligrams of follicle-stimulating hormone (FSH), containing 110 NIH-FSH-S1 units/mg, was isolated from 9 kg of equine pituitary glands. The equine FSH was dissociated into alpha- and beta-subunits. A tentative amino acid sequence of the alpha-subunit was determined. The alpha-subunit contained 82 amino acids. The equine FSH-alpha is shorter by 10 to 14 amino acids at the NH2 terminus and has several substitutions at several positions as compared with human FSH-alpha and bovine thyroid-stimulating hormone-alpha. At the intraspecies level, the alpha-subunits of human FSH, human luteinizing hormone, and human chorionic gonadotropin are similar, whereas at the interspecies level there are differences among the alpha-subunits of FSH, luteinizing hormone, and thyroid-stimulating hormone.

Amino Acid Sequence↗
PubMed1978

Amino acid sequence of the beta-subunit of the follicle-stimulating hormone from equine pituitary glands.

A tentative amino acid sequence of the beta-subunit of equine follicle-stimulating hormone (FSH) was derived from the sequences of tryptic, thermolytic as well as peptic, subtilisin, and chymotryptic peptides. Equine FSH-beta is analogous to human FSH-beta except six amino acid substitutions at positions 12, 16, 21, 62, 108, and 114. The amino acid sequence suggests that the hormone-specific beta-subunits of FSH are similar at the interspecies level, whereas the amino acid sequences of the hormone nonspecific alpha-subunits show variations.

Amino Acid Sequence↗
PubMed1978

Hormonal profile as a prognostic index of early threatened abortion.

Twelve pregnancies, in which the initial serum hCG titer as measured by RRA was subnormal, were studied to determine if a hormonal profile would serve as a prognostic index of spontaneous abortion. Three of the 12 patients delivered term babies. The hCG titers remained subnormal throughout the pregnancy, however, the serum E2, P, 17alpha-OHP, and PRL remained normal. One of the 12 patients aborted in week 25 of gestation. The serum hCG and PRL were subnormal; however, the serum E2, P, and 17alpha-OHP were normal. Eight of the 12 patients aborted prior to 100 days' gestation. The serum hCG, E2, and PRL were subnormal whereas the P and 17alpha-OHP were normal. Therefore, in patients who have subnormal serum hCG titers, serum E2 and PRL may provide a prognostic index of spontaneous abortion.

Abortion, Threatened↗
PubMed1978

A receptor-immunoassay for the determination of the specificity of anti-HCG-beta sera.

In the receptor-immunoassay, the binding of anti-HCG-beta sera to 125I-HCG and 125I-HLH is measured in the presence of bovine corpus luteum "receptor". Anti-sera specific for HCG show little binding with 125I-HLH. The receptor-immunoassay permits an evaluation of specificity, affinity and the ability of anti-HCG-beta sera to compete with the "receptor" for binding to 125I-HCG.

Binding Sites, Antibody↗
PubMed1978

A stimulatory effect of the fluid from preimplantation rabbit blastocysts upon luteinization of monkey granulosa cell cultures.

Blastocyst fluid was aspirated from Day 6 1/2--7 rabbit blastocysts and was added to cultures of granulosa cells obtained from preovulatory follicles of untreated rhesus monkeys or from follicles of monkeys or from follicles of monkeys treated with PMSG. The stimulation of progesterone secretion was measured and equated with that produced by hCG. The hCG-like activity was also measured in a radioreceptor assay using 125I-labelled hCG and porcine granulosa cells. In 8 out of 10 experiments with cultured cells from untreated monkeys, addition of 20% blastocyst fluid from Days 6--9 of culture stimulated progesterone secretion by 2- to 6-fold. Similar findings were obtained in 5 experiments with cultures from PMSG-treated monkeys except that the blastocyst fluid was added from Days 0 to 6 of culture. The granulosa cells in such cultures underwent morphological luteinization. Compared to a standard of purified hCG the blastocyst fluid contained about 0.76--2.5 ng hCG-like activity/ml which was non-dialysable. The radioreceptor assay indicated the presence of 0.5--2.5 ng hCG-like material/ml.

Animals↗
PubMed1978

Circulating pituitary-gonadal hormones in clomiphene-induced cycles.

Plasma follicle stimulating hormone (FSH) and luteinizing hormone (LH), prolactin (PRL), estradiol (E2), progesterone (P), testosterone (T), and dihydrotestosterone (DHT) were measured by radioimmunoassay in 7 patients who had ovulation induction with clomiphene citrate and human chorionic gonadotropin. Six of the 7 patients ovulated. There was higher increase in FSH than LH in 3 patients who also showed a midcycle FSH and LH peak. Plasma PRL was initially elevated in 2 patients, remained normal (less than 25 ng/ml) throughout the cycle in one patient, and showed an increase in the late luteal phase in 3 patients. Plasma E2 showed a good response at the end of clomiphene intake, with a subsequent preovulatory surge. Plasma P increased to more than 25 ng/ml in patients who ovulated and reached higher levels than in normal ovulatory cycles. Plasma T increased and decreased in a similar pattern to plasma E2 and was higher with clomiphene therapy than in the normal menstrual cycle. Plasma DHT remained similar to concentrations found in normal menstrual cycles. The findings are discussed in relation to the effect of clomiphene and these hormones on the pituitary-ovarian axis, ovulation rate, and conception rate.

Chorionic Gonadotropin↗
PubMed1977

Screening for twin pregnancy.

A group of 590 women who, 4 to 5 weeks after their last menstrual period, were confirmed to be pregnant, as measured by the human chorionic gonadotropin (hCG) by radioreceptor assay. Nine of these women had serum hCG levels approximately twofold higher than the others and were suspected of having twin pregnancy. When these women were tested at 12 weeks of gestation, pelvic sonography confirmed twin pregnancies in all the nine cases. Serum hCG levels thus provide a simple, rapid, and easy method to detect twin pregnancy.

Chorionic Gonadotropin↗