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Biomedical subjects

R Mathur

Publications and source records attributed to R Mathur.

At least 55 records · Page 3Linked to original sources
PubMed1993

Is the sleep apnoea/hypopnoea syndrome inherited?

BACKGROUND--The aetiology of the sleep apnoea/hypopnoea syndrome (SAHS) is unclear in many patients. Snoring, a prerequisite for SAHS, runs in families. A study was carried out to determine whether there is an increased frequency of irregular breathing during sleep in relatives of patients with SAHS. METHODS--A prospective study was performed of first degree relatives of 20 consecutive non-obese (BMI < 30 kg/m2) patients with SAHS. Questionnaires on SAHS symptoms were sent to all first order relatives and those living within 150 miles of Edinburgh were invited for overnight monitoring of their breathing, sleep, and oxygenation patterns in the sleep laboratory. RESULTS--Ten of the 40 relatives had more than 15 apnoeas + hypopnoeas/hour of sleep, and eight had more than five 4% desaturations/hour. These frequencies of irregular breathing and desaturation are significantly higher than in the British population. Cephalometric studies showed no skeletal abnormality but an increased uvular width was found in the affected relatives. CONCLUSIONS--There is an increased frequency of abnormal breathing during sleep in relatives of non-obese patients with SAHS.

Adult↗
PubMed1993

Mobilization and distribution of beryllium over the course of chelation therapy with some polyaminocarboxylic acids in the rat.

The efficacy of three common polyaminocarboxylic acids in the treatment of experimental beryllium intoxication was investigated in male rats. N-(2-hydroxyethyl) ethylene diamine triacetic acid (HEDTA) was more effective than calcium disodium ethylenediamine tetraacetic acid (CaNa2EDTA) in reducing the beryllium concentration of the blood, kidneys and spleen and reducing beryllium-induced inhibition of hepatic alkaline phosphatase activity. HEDTA was also most effective in reducing histopathological lesions in the liver and spleen. Compared to these two chelators, the third amino chelator, calcium trisodium diethylene triaminepenta acetic acid (CaNa3DTPA) produced severe deleterious effects in the liver and systemic toxicity. The results suggest that HEDTA is a promising chelator for beryllium toxicity while DTPA enhances the toxic manifestation of beryllium.

Animals↗
PubMed1993

Nephrolithiasis in children.

A study of 100 cases of nephrolithiasis between 3 to 15 years of age is reported. Seventy four cases were more than 10 years old. The common presenting symptoms included abdominal pain (69%), burning micturition (23%), gross hematuria (4%) and unexplained pyrexia (6%). Associated urinary tract malformations were found in 16 cases. Twenty four had struvite calculi. Urinary infection with Proteus mirabilis was found in 23 children and idiopathic hypercalciuria in 31 cases. Following surgical removal, either percutaneously or by open surgery, 8 patients had residual calculi and in 6 cases recurrence occurred.

Adolescent↗
PubMed1993

GABA B mediated analgesia in tonic pain in monkeys.

The present study was designed to characterise the analgesia produced by the GABA B agonist baclofen in tonic pain in monkeys. The effect of various doses of baclofen was studied on formalin induced pain. Baclofen was injected intraperitoneally 30 min prior to formalin injection in five doses of 2, 4, 6, 8, and 10 mg/kg and the pain was quantified for a period of one hour. Baclofen produced dose related analgesia, 6 mg/kg having maximal effect. The antinociceptive effect of baclofen could be attributed to the effect of baclofen on GABA B receptors producing presynaptic inhibition of primary nociceptive afferents in the dorsal horn of the spinal cord.

Analgesics↗
PubMed1992

Do patients with the sleep apnea/hypopnea syndrome drink more alcohol?

As alcohol ingestion may worsen the sleep apnea/hypopnea syndrome, we have investigated the alcohol consumption of patients with the sleep apnea/hypopnea syndrome in comparison to control subjects to determine whether patients with the sleep apnea/hypopnea syndrome drink excessively. A lifetime alcohol history was taken from each. There was no significant difference between the 50 patients with the sleep apnea/hypopnea syndrome and 95 age-matched controls in either the lifetime (patients 27, SEM 5 x 10(3); controls 26, SEM 4 x 10(3) units) or current (12, SEM 2; 12, SEM 2 units per week) alcohol consumption. There was no evidence that alcohol consumption was related to the development of arterial carbon dioxide retention or peripheral edema in such individuals.

Adult↗
PubMed1991

Ontogeny of phenylalanine (endogenous cholecystokinin) induced modulation of food intake in normal and undernourished rats.

1. The development of endogenous cholecystokinin (CCK) effects on food intake was studied in normal and undernourished growing rats of postnatal day 1-22. 2. Food intake was estimated by recording the gain in body weight before weaning. 3. l-phenylalanine, a potent stimulant of endogenous CCK release, suppressed 30 min food intake in normally nourished pups of day 7-15 or more but not of day 1-6 rats. 4. However, l-phenylalanine did not affect 24 hr gain in body weight day 1-6 or more, rat pups. 5. l-phenylalanine neither suppressed 30 min food intake nor affected 24 hr body weight in day 16-19 or 20-22 undernourished rat pups. 6. The study suggests that the endogenous CCK satiety effects appear early in the second week of postnatal life in normally nourished rats, whereas in undernourished rat pups it does not appear till day 20-22.

Animals↗
PubMed1991

Postcoital contraceptive action in rats of a hexane extract of the aerial parts of Ferula jaeschkeana.

The hexane extract of Ferula jaeschkeana aerial parts was studied at an oral dose of 25 mg/kg per day for its postcoital effects in pregnant rats. Ovaries of treated rats remained in a cyclic state rather than undergoing pregnancy as demonstrated by constant ovulation accompanied by newly formed corpora lutea. Follicles were present in different stages of development. Uterine histoarchitecture of treated rats appeared non-receptive for implantation. No decidcoma were observed on day 5 of pregnancy and the luminal epithelium remained unresponsive. Uterus was non-oedematous and lumen was considerably wider. Administration of the extract caused increases in the protein and glycogen content of ovary and uterus, while the activity of acid phosphatase remained essentially unchanged and the activity of alkaline phosphatase was increased. The volume of uterine fluid in the treated rats was increased considerably on day 5 post coitum. It appears that the histological and biochemical modifications in the ovary and uterus of treated pregnant rats do not support the preparation of uterus for implantation.

Alkaline Phosphatase↗
PubMed1991

Effect of inhaled prostaglandin E2 on bronchial reactivity to sodium metabisulphite and methacholine in patients with asthma.

Inhaled frusemide protects against the bronchoconstrictor response to a wide range of stimuli that cause bronchoconstriction by indirect mechanisms. One possible explanation for this protection relates to the known ability of frusemide to enhance synthesis of prostaglandin E2 (PGE2). Studies in vitro suggest that PGE2 might protect against indirectly acting bronchoconstrictor challenges rather than those that act directly on airway smooth muscle, though little is known about the effects of PGE2 in vivo. The effect of inhaled PGE2 on the bronchoconstrictor response to inhaled sodium metabisulphite (a stimulus with an indirect action) and methacholine (which acts directly on airway smooth muscle) was studied in nine patients with asthma. Subjects were studied on four days, inhaling PGE2 (100 micrograms) or placebo in a double blind fashion followed immediately by a cumulative dose challenge with sodium metabisulphite or methacholine. The response to the constrictor stimuli was measured as the provocative dose causing a 20% fall in FEV1 (PD20). There was no significant change in FEV1 after inhaled PGE2 compared with placebo, nor any significant change in the response to methacholine; the geometric mean methacholine PD20 was 0.9 mumol after PGE2 and 0.56 mumol after placebo (mean difference 0.7 (95% confidence limits--0.1, 1.5) doubling doses). PGE2, however, protected against sodium metabisulphite, the geometric mean sodium metabisulphite PD20 being 11.8 mumol after PGE2 and 1.8 mumol after placebo (mean difference 2.5 (95% CL 1.9, 3.1) doubling doses). PGE2 conferred significantly greater protection against sodium metabisulphite than methacholine (mean difference 1.8 (95% CL 0.8, 2.8) doubling doses). This suggests that PGE2, like frusemide, has an inhibitory effect on pathways relevant to the bronchoconstriction induced by sodium metabisulphite, with little or no effect on those relevant to methacholine.

Adolescent↗
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↗