Search PubMed⌕ Search

Biomedical subjects

P S Benny

Publications and source records attributed to P S Benny.

14 recordsLinked to original sources
PubMed2003

Evidence that oxytocin is a physiological component of LH regulation in non-pregnant women.

BACKGROUND: Regulation of the LH surge is central to the functioning of the female ovulatory cycle. In animal models, oxytocin has been shown to alter LH activity. Oxytocin advanced the LH surge and, conversely, oxytocin receptor antagonists inhibited full production of the LH surge in rats. Few data exist on the possibility that oxytocin modulates LH in women. METHODS: Ten non-pregnant women participated in this study over two menstrual cycles. One cycle was a control cycle, and the other a trial cycle; the two were separated by at least one cycle. When the diameter of an ovarian follicle was >15 mm, a subject was allocated at random into either a control or treatment group. In a control cycle, volunteers received normal saline; in a treatment cycle, volunteers received an oxytocin antagonist (atosiban). RESULTS: For treatment cycles, the maximum LH concentration was significantly less than that in control cycles (42.1 +/- 6.2 versus 60.3 +/- 8.3 IU/l respectively; P < 0.05). Maximum FSH and estradiol concentrations were not significantly different between the two groups. CONCLUSIONS: The results indicated that inhibition of endogenous oxytocin affects the endocrinology of the ovulatory cycle in women, and strongly suggest that oxytocin has a role in the physiological processes of LH regulation.

Adult↗
PubMed2001

The utility of plasma CRH as a predictor of preterm delivery.

It has been suggested that CRH is a placental clock that controls the duration of pregnancy and that the timing of the rise in CRH may permit prediction of the onset of labor. We have performed a prospective longitudinal study, in 297 women, to examine the utility of a single second-trimester plasma CRH measurement to predict preterm delivery. Venous blood samples were taken at 4-weekly intervals, beginning at 16-20 wk gestation, until delivery for CRH and its binding protein. A time point at which a single plasma CRH test might give optimal data to predict preterm delivery was determined. Thirty-one subjects delivered prematurely (10.4%). Sampling for plasma CRH at 26 wk gestation seemed the optimal time point to maximize sensitivity and specificity of the test. The mean (+/- SD) plasma CRH in women at this gestation who eventually delivered after spontaneous labor within 1 wk of their due date (39-41 wk, n = 127) was 34.7 +/- 27.0 pM. A plasma CRH of more than 90 pM at 26 wk gestation had a sensitivity of 45% and a specificity of 94% for prediction of preterm delivery. The positive predictive value was 46.7%. Calculation of free CRH did not improve these figures. In conclusion, a single measurement of plasma CRH, toward the end of the second trimester, may identify a group at risk for preterm delivery, but over 50% of such deliveries will be unpredicted. These data do not support the routine clinical use of plasma CRH as a predictor of preterm labor.

Corticotropin-Releasing Hormone↗
PubMed1999

Association of a novel human mtDNA ATPase6 mutation with immature sperm cells.

This study reports the first clearly defined heteroplasmic mutation in immature human sperm cells. The human sperm mitochondrial genome from residue 8186-9341 was analysed with the aim of identifying point mutations which may be associated with human male infertility. The semen samples analysed were obtained from 88 fertile men, 19 with oligozoospermia, and 12 with severe oligozoospermia. Using single strand conformation polymorphism analysis a heteroplasmic T to C transition was detected in the ATPase6 gene, at nucleotide position 8821, in semen samples from one out of 12 (8%) severely oligozoospermic men, but not in oligozoospermic men or normospermic men. This mutation changed the amino acid serine to proline at residue 99 of the mitochondrial ATPase6 in a region which is highly conserved in other vertebrates including rat, bovine, chicken, salmonids and Xenopus. The mutation was detected in semen samples collected from the same man 9 months apart and in peripheral blood lymphocytes. Single sperm cell analyses did not find this mutation in the mature sperm, but the mutation was detected in 7% of immature spermatids. Our finding suggests that immature spermatids with this mutation fail to develop fully.

Adenosine Triphosphatases↗
PubMed1998

The effect of recombinant follicle stimulating hormone (Gonal-F) on endogenous luteinizing hormone secretion in women.

Parenteral administration of follicle stimulating hormone (FSH) has been shown to lower luteinizing hormone (LH) concentrations in women undergoing ovulation induction. This study was designed to explore the physiological mechanism of this effect. Seven healthy women were recruited into a double-blind placebo-controlled study. LH secretion, after the administration of variable i.v. boluses (37.5, 75 and 150 IU) of recombinant FSH (Gonal-F), was evaluated. LH was measured at 10 min intervals for 2 h before and 4 h after the FSH/placebo infusion. LH pulse frequency and amplitude were evaluated and there was no significant difference between control and trial cycles for each subject. A linear regression analysis revealed that in the group receiving 150 IU FSH, the mean plasma LH concentration decreased significantly due to a reduction tonic LH secretion. This could be a result of the suppression of secretion or an alteration of clearance. This decrease was not seen in the other dosage groups, revealing that above a dosage threshold, FSH reduced non-pulsatile LH secretion. Therefore the effect of FSH in this study exposed the likely presence of two components of LH concentration: an FSH-sensitive, non-pulsatile tonic secretion and a gonadotrophin-releasing hormone-stimulated, pulsatile release that is unaffected by FSH. Although an indirect effect involving ovarian regulation is not excluded, the rapidity of the effect suggests that FSH acts directly on the pituitary gland.

Adult↗
PubMed1995

Pre-ovulatory oxytocin administration promotes the onset of the luteinizing hormone surge in human females.

Luteinizing hormone (LH) secretion during the ovulatory cycle is believed to be predominantly regulated by gonadotrophin-releasing hormone. Investigations in animals have strongly suggested that oxytocin also participates in LH control and the physiological events controlling LH surge initiation. In the human female, however, there has been no evidence supporting oxytocin's involvement in the processes leading to ovulation. In this study the effect of a preovulatory infusion of oxytocin on the onset of the LH surge was investigated in women aged 20-35 years who had natural ovulatory menstrual cycles of lengths between 25-35 days. Vaginal ultrasound scanning monitored follicular growth during the late follicular phase. When a follicle > 14 mm in diameter was observed each woman was randomized into one of two groups. One group (n = 8) received an oxytocin infusion of 256 mIU/min for 2 h, the other group (n = 8) received normal saline. The women who were administered oxytocin at this late follicular stage had an earlier onset of the LH surge than those who had received saline (P < 0.01). The results indicate that oxytocin promotes the onset of the LH surge in humans.

Adult↗
PubMed1991

Nutrition in pregnancy in the Wellington region.

The diets of 115 pregnant women in the Wellington region were assessed for nutrient intake using 24 h dietary recall. Assessment was performed in both the second and third trimester. Women came from three ethnic groups, European (61), Maori (29) and Pacific Islanders (25). Comparisons of nutrient intake were made between these groups. The overall energy intake was similar between the groups (range 4.8-19.7 MJ/d) but Maori (p less than 0.05) and Pacific Islanders (p less than 0.02) had a significant decrease in energy intake from second to third trimester. Pacific Islanders consumed significantly more starch (121 g/d, p less than 0.05) whereas Maori women consumed significantly more sucrose (86 g/d, p = 0.0002). The mean intake in Pacific Islanders contained significantly less calcium (882 mg/d, p = 0.0002) and zinc (9.0 mg/d, p = 0.014). Forty-four percent Europeans, 28% Maori and 51% Pacific Islanders had an estimated iron intake below the minimum safe intake for pregnancy. However dietary iron intake did not relate to the presence of anaemia nor whether iron supplements were given.

Adult↗
PubMed1987

Meconium aspiration--role of obstetric factors and suction.

Meconium aspiration occurred in 66 of 120 infants with meconium-stained liquor admitted to a Neonatal Unit. Four of the 66 infants died, whilst 17 other required ventilatory support. Meconium aspiration syndrome, especially when severe, was more likely if the mother was a smoker, hypertensive, anaemic, Maori or the pregnancy was greater than 42 weeks' gestation. Meconium aspiration was also associated with thick meconium, prolonged labour, late fetal heart decelerations and inadequate suctioning of the airway at birth. Although meconium-stained liquor is a common occurrence in labour, a bad neonatal outcome will only be obviated by vigilant intrapartum care and active suctioning of the infant's airway at birth. Once aspiration has occurred, intensive treatment is often required and sometimes fails.

Ethnicity↗
PubMed1984

Septic abortion in Wellington 1960-1979.

A retrospective analysis was made of 283 cases of septic abortion admitted to Wellington Hospital from 1960-1979. There was a substantial reduction in the annual numbers of admissions occurring at the end of the study period compared with the beginning. Morbidity as measured by hospital stay, haemorrhage and septicaemia also fell. Possible causes for the reduction are discussed.

Abortion, Septic↗
PubMed1978

The biochemical effects of a maternal hyperalimentation during pregnancy.

Six patients each with a very low 24-hour urine oestriol excretion were infused with hypertonic dextrose and amino acids for 48 hours prior to delivery. Amniotic fluid samples were studied before and after infusion. Lecithin sphingomyelin ratios and insulin levels were increased following infusions in all patients. There was usually a fall in amniotic fluid glucose and an increase in ammonia, amino acid nitrogen and osmolality following infusions. Maternal plasma oestriol, human placental lactogen, cystyl aminopeptidase and urine oestriol excretion were unchanged during the infusions.

Amino Acids↗
PubMedDate not supplied

Amniotic fluid endocrine changes during maternal hyperalimentation.

Ten women with low estriol excretion received hyperalimentation prior to induction of labor. Six received an amino acid mixture (5% Aminofusin) and 25% dextrose, two received the amino acid mixture, and two received 25% dextrose. Amniotic fluid obtained before and after hyperalimentation was assayed for fetal surfactant production, thyroid, pituitary, and carbohydrate regulating hormones. In the combined amino acid/dextrose infusion group the amniotic fluid palmitic acid levels increased significantly post infusion; rT3 also increased significantly but T3 and T4 showed no significant change. The pituitary hormones growth hormone, prolactin, and ACTH showed no significant change, but beta-endorphin-like activity was significantly elevated. No thyroid-stimulating hormone was detected in any of the samples. All the carbohydrate regulating hormones, insulin, cortisol, and cAMP, showed significant increases but cGMP showed a significant decrease. The amino acid and dextrose only groups gave similar results. Seven of the infants showed some degree of intrauterine growth retardation but no neonatal complications attributable to the hyperalimentation.

Amino Acids↗