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Biomedical subjects

H Singh

Publications and source records attributed to H Singh.

At least 253 records · Page 14Linked to original sources
PubMed1993

Potassium therapy of hypertension.

Hypertension is an important contributor to cerebrovascular and cardiovascular morbidity and mortality. Nonpharmacological treatment has been an important first-line therapy for mild hypertension. In the last decade, there is increasing evidence from epidemiological, interventional, and animal studies for the role of potassium supplementation in the management of hypertension. The antihypertensive effect of potassium is mediated predominantly via natriuresis. Hence, it is especially effective in the management of salt-sensitive essential hypertensive patients. In this review, we will summarize the available data and discuss the role of potassium supplementation in the management of essential hypertension.

Animals↗
PubMed1993

Effect of some pesticides/weedicides on cathepsin B activity and lysosomal membrane.

The in vitro inhibitory effects of various weedicides and pesticides on goat brain cathepsin B and their labilizing potency on the lysosomal membrane were quantitated. Endosulfan an organochlorine insecticide inhibited the enzymic activity to approximately 50% at 7 mM concentration followed by methyl parathion, aldrin, melathion and benzene hexachloride (BHC) in that order. Among the weedicides, butachlor was found to be most inhibitory (approximately 50% activity was lost at 6 mM) followed by isoproturone (28%) and anilophos (19%). When the labilizing/stabilizing potency of all these drugs was observed on lysosomal membrane it was found that none of these was capable of stabilizing the membrane. At 40 degrees C and 1 mM drug concentration, aldrin, endosulfan, melathion and anilophos were found to be strong labilizers of the lysosomal membrane. Others like isoproturone, BHC and methyl parathion had moderate labilizing effect. The labilization potency of the drugs was temperature dependent and was less pronounced at 25 degrees C as compared to 40 degrees C.

Animals↗
PubMed1993

Exclusive localization in peroxisomes of dihydroxyacetone phosphate acyltransferase and alkyl-dihydroxyacetone phosphate synthase in rat liver.

Dihydroxyacetone phosphate acyl transferase (DHAP-AT), alkyl dihydroxyacetone phosphate synthase (alkyl-DHAP-synthase), and glycerol-3-phosphate acyltransferase (GPAT) activities were investigated under optimal assay conditions using highly purified organelle preparations. The data presented clearly indicate that GPAT activity was mainly localized in mitochondria and microsomes, whereas DHAP-AT and alkyl-DHAP-synthase activities were exclusively localized in peroxisomes. A small fraction of the total DHAP-AT and alkyl-DHAP-synthase activities observed in purified mitochondrial preparations was due to the presence of intact peroxisomes. DHAP-AT and alkyl-DHAP-synthase activities were very low in purified microsomes (< 1% compared to peroxisomes) and these activities are thought to be due to sedimentation of peroxisomal fragments (generated during homogenization of liver and processing of liver homogenate) with microsomes. The results indicate that the dihydroxyacetone phosphate pathway does not contribute to the synthesis of glycerolipids other than ether lipids in rat liver. The ether bond formation occurs exclusively in peroxisomes, and all the biosynthetic reactions for plasmalogen synthesis may also be operating within peroxisomes in rat liver.

Acyltransferases↗
PubMed1993

Prevalence of copper resistant salmonellae in India.

Sixty eight of 330 strains of Salmonella belonging to three different serotypes, S. typhi, S. typhimurium and S. bareilly, referred to at the National Salmonella and Escherichia Centre, Central Research Institute, Kasauli, between 1989-1991 were found to be copper resistant. Maximum number of strains (39.1%) were resistant in S. bareilly serotype, followed by S. typhimurium (21.7%) and least in S. typhi (17.4%). Of the 15 States/Union Territories (UTs) from where Salmonella strains were received, copper resistance was observed in strains from 10 States/UTs. This resistance was maximum among the strains from Goa (85.7%).

Copper↗
PubMed1992

Very long-chain fatty acids in peroxisomal disease.

Fatty acids with from 24 to 28 carbon atoms (very long-chain fatty acids, VLCFA) are present in small amounts in all mammalian tissues. Even longer chain fatty acids with from 30 to 38 carbon atoms (ultra-long-chain fatty acids, ULCFA) are found in certain specialized tissues including retina, brain, and spermatozoa. In patients with inherited defects in peroxisomal structure and/or function, there is an accumulation of VLCFA in most tissues, while VLCFA and ULCFA levels are increased in brain. The most pronounced changes occur in those patients who have defects in peroxisomal assembly (Zellweger syndrome, infantile Refsum's disease, and neonatal adrenoleukodystrophy). In the brain of these individuals, ULCFA are distributed largely in molecular species of phosphatidylcholine with penta-, hexa-, and heptaenoic acids. In contrast, patients with X-linked adrenoleukodystrophy have increased levels of phosphatidylcholine with monoenoic rather than polyenoic ULCFA. A defect in a peroxisomal VLCFA CoA synthetase or ligase has been reported for these patients, but assembly of their peroxisomes is apparently normal. We speculate that ULCFA are normal products of carbon chain elongation. We have confirmed this by demonstrating the elongation of [1-14C]hexacosatetraenoic acid (26:4n-6) by rat brain in vivo to a series of longer chain tetraenoic acids with carbon chain lengths up to 34. Elongation to ULCFA can occur as well in non-neural tissues as shown by detection of labeled saturated and monoenoic fatty acids with up to 32 carbon atoms after incubation of normal and Zellweger syndrome fibroblasts with [2-14C] acetate. Increased labeling of VLCFA and ULCFA is observed in cells from patients with peroxisomal disorders. Our data suggest that ULCFA with up to at least 32 carbon atoms are formed normally, as a part of the elongation process in most mammalian tissues, and that control of carbon chain elongation is a major function of peroxisomes. Impairment of this function as occurs in peroxisomal disease results in the accumulation of VLCFA and ULCFA. The relative enrichment in normal tissues of ULCFA such as 32:6n-3 in ram and bull spermatozoa and 36:4n-6 in human and rat brain suggests a probable physiological role for this class of fatty acids in these tissues.

Adolescent↗
PubMed1992

Spinal anaesthesia with lidocaine 2% for caesarean section.

Spinal anaesthesia with 2, 2.5 or 3 ml of glucose-free lidocaine 2% was studied in 50 patients undergoing Caesarean section. Onset time, cephalad spread of analgesia, quality of analgesia, muscle relaxation, the cardiovascular effects and duration of analgesia and motor block were assessed. Reliable anaesthesia was provided with 2.5 and 3 ml while 2 ml of 2% lidocaine was insufficient. Onset time varied between 5.5 to 6 min and maximum cephalad spread was achieved in 10-15 min. The mean maximum extent of sensory analgesia was higher after 2.5 ml (T4.1) and 3 ml (T3.6) than after 2 ml (T7) (P < 0.001). Complete motor block was achieved in all the patients. The mean duration of sensory block was 123 +/- 6.23 min (2 ml) to 126 +/- 7.53 min (2.5 and 3 ml). The mean duration of motor block in 2.5 and 3 ml groups was higher (P < 0.001) than in the 2 ml group and was correlated with the dose of lidocaine (P < 0.05). Hypotension (SBP < 100 mmHg) was noted in 10% (n = 5) of patients in whom the cephalad spread of analgesia was also higher. All the neonates had an apgar score of 7 or more at 1 min. These results suggest that 2.5 to 3 ml of 2% lidocaine provides satisfactory anaesthesia for Caesarean section.

Adult↗
PubMed1992

Hepatotoxicity of high dose salicylate therapy in acute rheumatic fever.

Liver function tests, including serum alanine aminotransferase (ALT) activity, serum bilirubin, alkaline phosphatase, serum proteins, blood ammonia levels and intravenous glucose utilization, were monitored in 50 children with acute rheumatic fever receiving anti-rheumatic doses of aspirin. There was a significant increase in blood ammonia levels and serum ALT after aspirin therapy. A significant fall in glucose utilization coefficient was also recorded. Serum alkaline phosphatase, bilirubin and total proteins did not change significantly. Twenty-two of the 50 children recorded a rise in serum ALT; in 12, the rise was five- to tenfold. These 12 children developed adverse symptoms to aspirin. Also, all had a marked rise in blood ammonia levels. The children improved clinically and biochemically on withdrawal of aspirin. There was no constant relationship between hepatocellular function and serum salicylate levels.

Acute Disease↗
PubMed1992

Management of accidental kerosene ingestion.

Accidental kerosene ingestion is still a common problem in Libya. It causes considerable morbidity and occasionally mortality. The role and choice of antibacterial agents in its management remain unsettled. Pulmonary damage has been reported as resulting from aspiration. In aspiration pneumonia, anaerobic organisms may be important pathogens and metronidazole may have a place in therapy. The present randomized trial in 100 children with accidental kerosene ingestion assesses the role of ampicillin, carbenicillin and metronidazole in its management. The results are not conclusive but chemoprophylaxis appears to decrease morbidity. Of the various regimens used, the ampicillin/metronidazole combination was found to be slightly better than the others. Further study is recommended.

Accidents↗
PubMed1992

Ventilatory effects of laparoscopy under general anaesthesia.

We have studied 14 female patients undergoing elective laparoscopy under general anaesthesia with peritoneal insufflation of carbon dioxide in order to examine changes in physiological deadspace (VDphys), arterial to end-tidal carbon dioxide partial pressure difference (PaCO2-PE' CO2) and PaCO2. VCO2 increased after insufflation of carbon dioxide with a mean (SD) maximum increase of 32 (28)% compared with the preinsufflation value. PaCO2 increased also, with a mean (SD) maximum increase of 0.6 (0.58) kPa immediately before carbon dioxide deflation. VDphys and (PaCO2-PE' CO2) increased during laparoscopy, but this was not significant (P greater than 0.05).

Adult↗
PubMed1992

Choice of toothbrush: a survey of dentists' personal preferences and recommendations for patients.

Data on dentists' choice of toothbrush brand/type for personal use and their recommendations for patients were obtained by means of a questionnaire. Seventy-nine per cent of dentists surveyed received free samples, with Oral-B comprising 33 per cent of all such samples, followed by Colgate (16 per cent) and Tek (13 per cent). Fifty-three per cent of dentists surveyed indicated they used all free samples received. Sixty-two per cent of dentists do not consider that different brushes differ significantly in their plaque-removing ability. Therefore, while an effective toothbrushing technique is important, selection of the 'correct toothbrush' from the wide range available may not be critical. The results of the present investigation provide information that is relevant to dental health education and can be applied at the chairside as well as at the broader community level.

Adolescent↗
PubMed1992

BLyF, a novel cell-type- and stage-specific regulator of the B-lymphocyte gene mb-1.

The mb-1 gene encodes an integral membrane protein that appears to be required for the surface expression and signalling function(s) of the immunoglobulin receptor on B lymphocytes. The gene is expressed in a lineage-restricted manner. It is activated early in B-cell ontogeny, continues to be expressed in mature B cells, but is turned off in terminally differentiated plasma cells. We have identified the mb-1 promoter and functionally tested its activity by transient transfections. A 737-bp promoter fragment preferentially stimulates accurately initiated transcription in mb-1-expressing B cells. Deletion analysis of the promoter suggests the presence of two functional domains, proximal and distal. Both domains independently activate transcription from a heterologous promoter. The distal domain functions in a cell-type- and stage-specific manner, activating transcription in B cells but not in T cells or plasma cells. A 25-bp element within this domain is necessary and sufficient for activity. This element is recognized by a novel cell-type- and stage-specific transcription factor termed BLyF. The binding of BLyF completely correlates with the ability of the regulatory element to stimulate transcription. Thus, BLyF appears to positively regulate transcription of the mb-1 gene. Our results also suggest that the inactivity of the mb-1 locus in plasma cells is not simply due to the loss of BLyF activity.

Animals↗
PubMed1992

Timing of acute clinical response to fluphenazine.

The time course of clinical improvement was studied in 41 schizophrenic and schizoaffective acute in-patients treated for 28 days with 10, 20 or 30 mg/day of oral fluphenazine hydrochloride in a double-blind, randomised study. Significant improvement was seen in the four BPRS factors: thinking disturbance, hostile-suspiciousness, withdrawal-retardation and anxious depression. The first two of these factors were improved by day 5. Significant improvement was seen up to day 22 for three of the four factors, but without significant improvement during the last week (although scores continued to drop). The half of the sample showing greater overall improvement did not improve faster than the sample as a whole. These more improved subjects did not differ significantly from the less improved subjects in the thinking disturbance factor until day 15, suggesting that at least a two-week neuroleptic trial would be necessary to begin to differentiate more and less responsive patients. The longer-term course of improvement cannot be determined from these data. The withdrawal-retardation and anxious depression factors showed their greatest improvement later than the 'positive' symptom factors, suggesting that the former may improve as a result of change in the latter.

Acute Disease↗