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Biomedical subjects

R Mathur

Publications and source records attributed to R Mathur.

At least 73 records · Page 4Linked to original sources
PubMed1991

Testosterone increases thromboxane A2 receptors in cultured rat aortic smooth muscle cells.

Previous studies have demonstrated increased contractile responses to thromboxane A2 (TXA2) mimetics in aortas obtained from male rats compared with those obtained from females. This study was designed to determine the effects of testosterone and 17 beta-estradiol treatment on TXA2 receptors in cultured rat aortic smooth muscle cells (RASMCs). TXA2 receptor affinity and density were determined through equilibrium binding experiments using the TXA2/prostaglandin H2 mimetic [1S-(1 alpha,2 beta(5Z),3 alpha(1E,3R*),4 alpha)]-7-[3-(3- hydroxy-4-(4'-125iodophenoxy)-1-butenyl)-7-oxabicyclo[2.2.1]hep tan-2-yl]- 5-heptenoic acid (125I-BOP). Incubation with testosterone (100 nM) for 24 or 48 hours resulted in a significant (p less than 0.05) 31% and 48% increase in TXA2 receptor density without any change in affinity. 17 beta-Estradiol (100 nM) had no significant effect on either the density or affinity of TXA2 receptors. Coincubation with the testosterone receptor antagonist hydroxyflutamide (1 microM) blocked the testosterone-induced increase in TXA2 receptor density. The maximum increase in intracellular free calcium induced by I-BOP was significantly (p less than 0.05) greater in testosterone-treated RASMCs than controls. Similarly, increases in inositol trisphosphate induced by the TXA2/prostaglandin H2 mimetic U46619 were significantly (p less than 0.05) greater in testosterone-treated RASMCs compared with controls. The results demonstrate that testosterone increases vascular TXA2 receptor density and support the notion that sex steroid hormones modulate the expression of this receptor.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1990

Concentrations of Na+ and K+ in serum and uterine flushings of ovariectomized, pregnant and cyclic rats when treated with extracts of Hibiscus rosa sinensis flowers.

The effect of 50% ethanol and benzene extracts of Hibiscus rosa sinensis flowers was studied on the concentration of Na+ and K+ in the serum and uterine flushings of ovariectomized, mated and cyclic rats. In ovariectomized rats, both extracts given alone did not alter the K+ content of the uterine flushings but when administered with estradiol dipropionate (EDP), a partial antagonism was observed when compared to EDP given alone. Conjoint treatment of extracts with EDP plus progesterone did not induce any significant change. In mated rats, both extracts did not alter the concentration of Na+ on the day of implantation but decreased significantly the concentration of K+ in uterine fluid. In cyclic rats, the administration of the extracts for 6 and 12 days did not cause any significant change in the concentration of K+ of uterine flushings but their administration for 18 days caused a significant decrease. In all three experiments, the concentration of Na+ in uterine flushings and of Na+ and K+ of serum did not show any significant changes.

Animals↗
PubMed1990

Effect of chronic treatment of Ro 15-1788 and its withdrawal on cortical and hippocampal EEG activity in rats.

Effect of chronic treatment with Ro 15-1788, a benzodiazepine (BZ) receptor antagonist, and its withdrawal, on the cortical and hippocampal electroencephalogram (EEG) was investigated in rats. Chronic treatment with Ro 15-1788 and its withdrawal (24 and 48 hr) were found to reduce the EEG amplitude in both cortical and hippocampal regions. This reduction in cortical and hippocampal EEG amplitude produced by chronic treatment with Ro 15-1788 and its withdrawal was reversed by gamma aminobutyric acid (GABA), pentobarbitone and picrotoxin, agents known to modulate the GABA/BZ synaptic events by acting at different sites on the complex. Baclofen a GABAB agonist and FG7142, a BZ inverse agonist were found to further reduce the EEG amplitude in the cortical and hippocampal regions of these rats, chronically treated with Ro 15-1788. Diazepam, a BZ agonist was found to have no significant effect on the alteration produced in the cortical and hippocampal EEG amplitude by chronic treatment with Ro 15-1788 or its withdrawal. It is suggested that the conformational changes produced on the GABA/BZ receptor complex by BZ receptor occupation, has a facilitatory effect on the actions of those drugs which act on the GABA/BZ receptor complex and the direction of this enhancement depended on the nature of the drug.

Animals↗
PubMed1989

Histoarchitecture of the genital tract of ovariectomized rats treated with an aqueous extract of Moringa oleifera roots.

The effect of an aqueous extract of Moringa oleifera roots was studied histologically on the genital tract of ovariectomized rats in the presence and absence of estradiol dipropionate and progesterone. Administration of the extract itself stimulated the uterine histoarchitecture as revealed by increases in the height of luminal epithelium, well developed glands, loose stroma and rich vascularity. The cervix showed metaplastic changes in the epithelium with marked keratinization. In the vagina, cornification was very prominent, rugae increased and stroma was loose. Conjoint administration of the extract with estradiol showed a synergistic action, and an inhibition was observed when administered conjointly with progesterone.

Abortifacient Agents↗
PubMed1989

Liv-52 protection against beryllium toxicity in female albino rats.

Toxic effects of beryllium salts on the reproductive organs of cyclic adult female albino rats have been studied. An attempt was made to overcome these effects using an Ayurvedic medicine Liv-52 (Himalaya Drug Co., Bombay). Liv-52-primed rats (1 mL/rat/day for 15 days) were exposed to beryllium nitrate intravenously and were sacrificed at different time intervals. At autopsy ovary, uterus, cervix, and vagina were processed for biochemical and histopathologic examination. Histoarchitecture of the ovary, uterus, cervix, and vagina revealed severe necrotic changes with beryllium nitrate treatment. Tissue glycogen content and the activity of alkaline phosphatase were inhibited significantly after beryllium treatment. Total and esterified cholesterol levels increased significantly in these organs when exposed to beryllium salts. However, a significant improvement was observed in the biochemical parameters and histoarchitecture of these organs when beryllium was injected into Liv-52-primed animals.

Acid Phosphatase↗
PubMed1989

Malignant hypertension presenting as acute pancreatitis.

We report a patient who was admitted to hospital with acute pancreatitis but who also had malignant phase hypertension. Whilst his alcohol intake was high, there was no objective evidence of alcoholic liver disease and no other underlying cause for pancreatitis was found. The pancreatitis may therefore have been due to pancreatic infarctions associated with fibrinoid necrosis. In all patients with acute pancreatitis, the diagnosis of malignant hypertension should be considered.

Acute Disease↗
PubMed1989

Immune status following measles vaccination in infants and evaluation for the need of revaccination.

In this prospective study, immune status of children vaccinated in infancy was determined at age 12-18 months. In 200 children, preimmunization protective measles hemagglutination (HI) antibody titres (greater than or equal to 1:8) were present in 38.5% of children of 6-8 months, the frequency decreased to 17.6 and 14.3% in age groups 9-11 and 12-18 months, respectively followed by an increasing incidence of 52.5% in those more than 18 months of age. Paired measles HI titre was estimated in 56 children, the post vaccination sample was taken at age 12-18 months, 3-9 months after measles vaccination. Most of the children (98.0%), with no detectable antibody titre, had a protective titre. Again a significant number (p less than 0.001) of children aged 12-18 months had protective HI titres compared to non-vaccinated. These findings suggest that when vaccinated at 9-11 months in our country, there is no need for revaccination later.

Antibodies, Viral↗
PubMed1988

Co2+-mediated time- and temperature-dependent activation of neutral alpha-D-mannosidase from monkey brain.

Neutral alpha-D-mannosidase from monkey brain was purified by Co2+-chelate affinity chromatography and immunoadsorbent affinity chromatography. The purified enzyme, with subunit Mr 45,000, was essentially homogeneous with only traces of two contaminant proteins as revealed by SDS/polyacrylamide-gel electrophoresis and AgNO3 staining. The purified enzyme, on preincubation with Co2+ at 37 degrees C or 60 degrees C followed by assay, showed a time-dependent enhancement in activity. The enhanced activity of the enzyme persisted even after removal of the Co2+. Bacitracin could partially prevent the activation. An aminopeptidase activity that was stimulated by Co2+ both at 37 degrees C and at 60 degrees C was present in the purified enzyme. After preincubation of the enzyme with Co2+ there was evidence for the release of amino acids, as revealed by t.l.c., but the Mr determined by SDS/polyacrylamide-gel electrophoresis was not appreciably altered. It is suggested that a Co2+-stimulated thermostable aminopeptidase, inseparable from the neutral mannosidase, may be involved in the stimulation of neutral mannosidase activity during its preincubation with Co2+.

Amino Acids↗
PubMed1988

Antifertility profile of the aqueous extract of Moringa oleifera roots.

An aqueous extract of Moringa oleifera roots was investigated for its estrogenic, anti-estrogenic, progestational and antiprogestational activities. Oral administration of extract progressively increased the uterine wet weight of bilaterally ovariectomized rats. This estrogenic activity was supported by stimulation of uterine histo-architecture. When the extract was given conjointly with estradiol dipropionate (EDP), there was a successive reduction in the uterine wet weight when compared to the gain with EDP alone and uterine histological structures were also inhibited. In the deciduoma test, the highest dose of 600 mg/kg interfered with the formation of deciduoma in 50% of the rats, showing some antiprogestational activity. Doses up to 600 mg/kg of the extract orally failed to induce a decidual response in the traumatized uterus of ovariectomized rats. The antifertility effect of the extract appears to be due to multiple attributes.

Animals↗
PubMed1987

Metastatic neuroblastoma after 52 years of dormancy.

A metastatic neuroblastoma arose in a posterior mediastinal tumor that had been present for at least 52 years. The diagnosis of neuroblastoma was first made when the patient was 81 years of age from biopsy of a metastatic lesion to the femur and later from biopsy of the mediastinal mass.

Aged↗