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Biomedical subjects

B N Roy

Publications and source records attributed to B N Roy.

At least 19 recordsLinked to original sources
PubMed2000

Plant regeneration from leaf explants of mulberry: influence of sugar, genotype and 6-benzyladenine.

A protocol for plant regeneration from leaf explants was developed for tropical mulberry varieties. Effect of sugars, 6-benzyladenine and genotype on shoot regeneration was studied. Highest percentage of shoot regeneration (80 +/- 6) was obtained with genotype S799 on medium containing glucose and 8.9 microM 6-benzyladenine. Genotypes Mandalaya and MIHP, having thicker leaves with waxy cuticle, showed poorer regeneration ability than S799 and Sujanpur-5, which have thinner leaves and cuticle. Histological studies revealed that shoots regenerated from sub-epidermal cells.

Adenine↗
PubMed1999

The effects of estrogen and progesterone on corticotropin-releasing hormone and arginine vasopressin messenger ribonucleic acid levels in the paraventricular nucleus and supraoptic nucleus of the rhesus monkey.

Ovarian steroids increase hypothalamic-pituitary-adrenal (HPA) axis activity and sensitize the hypothalamic-pituitary-ovarian (HPO) axis to stress-induced inhibition. The present study investigated the effect of ovarian steroids on CRH and arginine vasopressin (AVP) messenger RNA (mRNA) levels in the rhesus monkey hypothalamus, as both neuropeptides have been shown to stimulate the HPA axis and inhibit the HPO axis in this species. This was accomplished by measuring CRH and AVP mRNA in the paraventricular nucleus (PVN) and supraoptic nucleus (SON) by in situ hybridization histochemistry. Menstrual cycles were simulated in ovariectomized (OVX) rhesus monkeys by sequential addition and removal of SILASTIC brand (Dow Corning Corp.) tubing containing either 17beta-estradiol (E2) or progesterone (P4). On the morning of day 11 of the simulated follicular phase (E2 alone) or day 21 of the luteal phase (E2 + P4), animals were anesthetized, and the brains were perfused with paraformaldehyde via the carotid artery. Coronal sections (30 microm) were cut, and mRNA for CRH and AVP in the paraventricular nucleus (PVN) and supraoptic nucleus (SON) were semiquantified by in situ hybridization. CRH mRNA in the PVN of E2-replaced OVX animals (n = 7) was 2-fold greater than that in untreated OVX controls (n = 4), whereas CRH mRNA after E2 + P4 (n = 4) was no different from that in controls (optical density + SEM, 0.38 +/- 0.06, 0.13 +/- 0.08, and 0.14 +/- 0.09 for OVX + E2, OVX + E2 + P4, and OVX, respectively; P = 0.02). CRH in the SON was undetectable. In contrast to CRH, AVP mRNA in the PVN and the SON was similar in the three treatment groups. We conclude that E2 and E2 + P4 replacement to OVX monkeys exert different effects on CRH and AVP gene expression, as estrogen stimulation of CRH mRNA in the PVN was abrogated by progesterone, whereas no effect of ovarian steroids on AVP mRNA in either the PVN or SON was observed. We postulate that ovarian steroid regulation of CRH synthesis and release may in part explain the central nervous system mechanisms by which ovarian steroids affect the HPA and HPO axes during basal and stress conditions.

Animals↗
PubMed1997

Effect of continuous and multiple doses of 5-aminolevulinic acid on protoporphyrin IX concentrations in the rat uterus.

The objective of the present study was to determine if the concentration of protoporphyrin IX (PpIX) in the rat endometrium could be increased by administering 5-aminolevulinic acid (ALA) in multiple doses or by continuous infusion. The effect of pH, temperature and time in solution on the stability of ALA were also investigated. Estrogen-filled silastic capsules were implanted subcutaneously into ovary intact female rats (200-225 g) (n = 66). On the third day of hormonal priming, ALA (10 mg or 25 mg) dissolved in saline and adjusted to a pH of 5-5.5 was administered intrauterine either as a single bolus or as two injections 3 hours apart (n = 10). A fifth group of rats was infused with 25 mg ALA over a 12 hour period using an osmotic minipump (n = 6). In a second experiment, ALA (25 mg) was injected immediately after being dissolved in saline (pH 2) (n = 16) or after incubation at 37 degrees C for 12 hour (pH 2) (n = 7). PpIX was then extracted from the endometrium and myometrium using a 1:1 methanol/perchloric acid solution and quantified spectrofluorometrically. A dose-response relationship was observed between 10 and 25 mg of ALA and endometrial PpIX concentrations. However, no differences in endometrial PpIX concentrations were detected between rats administered ALA either as a single bolus or as two doses. Continuous infusion of 25 mg of ALA resulted in statistically lower endometrial PpIX concentrations compared to 25 mg ALA injected either as a single bolus or as two injections. Neither pH, temperature, nor time in solution affected ALA-induced PpIX accumulation. We conclude that the simplest way of achieving the highest PpIX concentration in the rat endometrium in vivo is to administer a bolus injection of 25 mg of ALA.

Aminolevulinic Acid↗
PubMed1995

Progesterone, estradiol, and prolactin involvement in lactation, including lactation following a postpartum mating, in the Djungarian hamster (Phodopus campbelli).

The endocrinology of lactation in the Djungarian hamster was investigated through once-daily sampling of females on Days 0, 3, 6, 9, 12, 15, and 18 postpartum. Serum prolactin (PRL) was elevated during early lactation but declined with time. Serum progesterone (P4) levels were uniformly low, and serum estradiol (E2) levels increased after Day 9. New CL were formed after the postpartum ovulation and persisted throughout lactation. During the first 9 days, the CL had the high P4 content typical of pregnancy. After Day 9, each individual CL decreased in P4 content and increased in E2 content. As evidenced by the reappearance of large antral follicles, lactating females probably returned to ovulatory cycles at about that time. The Djungarian hamster has a postpartum estrus and is capable of delivering a second litter without a diapause (18 days), although the majority of second litters are delayed. Mating during the postpartum estrus had no detected effect on growth or survival of the first litter. Second pregnancies were developmentally delayed by 3 to 7 days. P4 was effectively absent from serum for the first 12 days after mating. Although CL contained high levels of P4, the CL remained small and poorly vascularized. Mated females did not have higher serum P4 levels than nonpregnant, lactating females until Day 18. In response to the competing demands of lactation and concurrent gestation, the endocrine conditions associated with pregnancy were the most affected.

Animals↗
PubMed1977

Performance evaluation of BK amputees through graded load carrying tests.

The ergonomic approach to performance evaluation in orthopaedic rehabilitation presents problems because of the cumbersome and time-consuming measurement and test procedures involved. This paper describes a method of performance evaluation through graded load carrying tests which makes it possible to set up regression equations which can be used in routine clinical practice for prediction of the performance of below-knee amputees.

Adult↗