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Biomedical subjects

R Srivastava

Publications and source records attributed to R Srivastava.

At least 109 records · Page 6Linked to original sources
PubMed1990

Salmonella typhimurium-associated severe protracted diarrhea in infants and young children.

Eleven (13.8%) children (4-14 months; mean of 7.8 +/- 3.6 months) presenting with protracted diarrhea (duration greater than 21 days) and weight loss had associated infection with Salmonella typhimurium. All had documented weight loss of 16-25% and progressive clinical deterioration. On admission, they had high purging rates (greater than 4 ml/kg/h), hyponatremia (5/11), mucosal injury, and malabsorption as measured by 1 h blood D-xylose, fecal alpha 1-antitrypsin, and oral fat tolerance test. Diarrhea was secretory in 8 of 11 and fecal sodium was high (54-142 mEq/L; mean of 102 +/- 27 mEq/L). The organism showed multiple drug resistance. All patients received antibiotics (amikacin and nalidixic acid/norfloxacin) for 10-14 days, which was followed by rapid improvement in clinical status and absorption studies. The two youngest patients died. Due to ethical reasons, an untreated control group was not included. Use of appropriate antibiotics may benefit children with S. typhimurium-associated severe protracted diarrhea and rapid progressive weight loss.

Amikacin↗
PubMed1990

Transcription analysis, physical mapping, and molecular characterization of a nonclassical human leukocyte antigen class I gene.

The human major histocompatibility complex contains approximately 20 class I genes, pseudogenes, and gene fragments. These include the genes for the three major transplantation antigens, HLA-A, HLA-B, and HLA-C, as well as a number of other genes or pseudogenes of unknown biological significance. Most of the latter have C + G-rich sequences in their 5' ends that are unmethylated in the B-lymphoblastoid cell line 3.1.0. We investigated one of these genes, HLA-H, in more detail. The gene is, overall, strongly homologous in sequence to HLA-A but differs in several potentially significant ways, including changes in conserved promoter sequences, a single-base deletion producing a translation termination codon in exon 4, and a region of sequence divergence downstream of the transcribed portion of the gene. Nevertheless, mouse L cells transfected with the gene accumulated small amounts of apparently full-length polyadenylated RNA. A portion of this RNA begins at the transcription site predicted by analogy to certain class I cDNA clones, while another portion appears to begin shortly upstream. L cells transfected with a hybrid gene containing the first three exons of HLA-H and the last five exons of HLA-B27 accumulated full-length HLA transcripts at the same level as cells transfected with an HLA-B27 gene; both levels are at least 15- to 20-fold higher than that directed by HLA-H alone. In addition, we isolated a cDNA clone for HLA-H that contains a portion of intron 3 attached to a normally spliced sequence comprising exons 4 through 8. These results suggest that low levels of translatable mRNA for the truncated class I heavy chain encoded by HLA-H are produced under physiologic circumstances and that sequences 3' of intron 3 decrease the levels of stable transcripts.

Amino Acid Sequence↗
PubMed1990

Nephronophthisis with bronchiectasis.

A boy with nephronophthisis and bronchiectasis, a previously unrecognised association is described. Electron-microscopic examination of a renal biopsy from an asymptomatic sibling revealed marked thickening and lamination of the tubular basement membranes.

Biopsy↗
PubMed1990

Circadian variation of serum urea concentration in north Indian subjects.

Circadian rhythm of serum urea concentration was studied in 25 clinically healthy, diurnally active, nocturnally resting young male Indians. The mean urea concentration was observed to be 22.32 mg/dl at 0800 h which increased gradually reaching maximum at 0000 h with a mean of 31.00 mg/dl. A marked circadian variation in serum urea was recorded with a statistically significant amplitude and acrophase at 2232 h (Cosinor analysis). The observation that serum urea concentration oscillates physiologically in the peripheral blood according to a circadian rhythm may prove to be of importance in the clinical interpretation of values at different times along the 24 h light-dark period.

Adolescent↗
PubMed1990

Interaction of ethanol, cholesterol and vitamin A on phospholipid methylation in hepatic microsomes of rats.

Effect of ethanol, cholesterol and vitamin A either alone or in combination has been studied on cyt P450 and phospholipid methylation in hepatic microsomes of rats. Ethanol increased cyt P450 activity and decreased phospholipid methylation. Cholesterol effects were opposite to ethanol. Combination of cholesterol and ethanol decreased cyt P450 activity and increased phospholipid methylation. Vitamin A, which alone did not affect cyt P450 activity and phospholipid methylation behaved like cholesterol when given along with ethanol.

Animals↗
PubMed1989

Isolation and characterization of ribosomal DNA variants from Sciara coprophila.

The ribosomal RNA multigene family in the fungus fly Sciara coprophila contains a total of only 65 to 70 repeat units. We explored the types and frequencies of variant repeats in this small multigene family by characterizing different cloned rDNA variants from Sciara. Although we did not observe any intergenic spacer length variants in Sciara, we found a variant due to the insertion of a putative mobile element (lambda Bc11), and variants containing ribosomal insertion elements. By DNA sequence analysis of rDNA/non-rDNA junctions, there are three distinct types of ribosomal insertion elements found in Sciara rDNA: two correspond to the R1 and R2 insertion elements found in other dipterans (clones lambda Bc5 and pBc1L1, respectively), and one is a novel class of ribosomal insertion elements (R3, exemplified by clone pBc6D6) which so far is unique to Sciara. Together, the several different rDNA variants make up from 12 to 20% of the rDNA in Sciara. These results are discussed in the context of evolution of the ribosomal RNA multigene family.

Animals↗
PubMed1989

Role of free radicals in pulmonary thromboembolism in mice.

Involvement of free radicals and their scavenging enzymes in mice pulmonary thromboembolism, induced by intravenous infusion of collagen and adrenaline, has been studied. Malonaldehyde (MDA) and activities of xanthine oxidase (XO), catalase (CAT) and superoxide dismutase (SOD) were estimated in platelets, heart and lung homogenates. MDA increased in all the tissues sharply, while animals showed 70-80% thrombocytopenia. Xanthine oxidase activity in these animals increase significantly in heart. However, increased SOD activity and decreased catalase activity was observed in platelets. Intravenous administration of superoxide dismutase (5 mg/kg), catalase (5 mg/kg) and mannitol (200 mg/kg) protected the mice against pulmonary thromboembolism. The importance of free radicals in mice pulmonary thromboembolism has been demonstrated.

Animals↗
PubMed1989

Antithrombotic effect of thiopurinol.

Antithrombotic activity of ten pyrazolo pyrimidine derivatives was tested in mouse pulmonary thromboembolism model. Out of these compounds, Thiopurinol (C5H4N4S) showed dose-dependent protection in mice from death/paralysis induced by collagen + adrenaline. It also caused dose-dependent inhibition of thrombus formation in the cat. Thiopurinol inhibited aggregation of platelets induced by ADP and arachidonic acid but did not inhibit superoxide generation. It had no antiinflammatory activity nor any effect on cardiovascular system. The results indicate that the antithrombotic activity of the compound is mediated via inhibition of platelet aggregation.

Allopurinol↗
PubMed1989

Chromosomal transfer and in vivo cloning of genes in Vibrio cholerae using RP4::mini-Mu.

The RP4::mini-Mu replicon has been used to transfer chromosomal genes by conjugation and to clone in vivo metabolic, toxin and flagellar genes of Vibrio cholerae. RP4::mini-Mu was introduced into several strains of V. cholerae and these strains were mated with V. cholerae or Escherichia coli K-12 recipients. R'-episomes carrying the respective genes were maintained in recA recipients and were detected by complementation of auxotrophic, nontoxinogenic and aflagellate mutations in V. cholerae.

Cloning, Molecular↗
PubMed1989

Inhibition of neutrophil response by curcumin.

Blood neutrophils, when exposed to appropriate stimuli, aggregate, degranulate and generate superoxide anion. Curcumin, a non-steroidal antiinflammatory agent, modulated these functions, depending upon the kind of stimulus used. It inhibited monkey neutrophil aggregation induced by chemotactic peptide fmlp and zymosan activated plasma (ZAP) but did not affect that induced by serum treated zymosan (STZ) and arachidonic acid (AA). Generation of O2- radical was inhibited by curcumin, when cells were stimulated by AA, STZ and fmlp. Curcumin inhibited the release of myeloperoxidase, an azurophilic granule marker enzyme. Release of lysozyme was less susceptible to inhibition by curcumin. The results suggest that curcumin interferes with neutrophil responses to various physiological stimuli and a part of its antiinflammatory action is mediated via inhibition of neutrophil function. Inhibition of neutrophil function by curcumin appears to be mediated via calcium dependent mechanisms.

Animals↗
PubMed1989

Enteroaggregative Escherichia coli associated with persistent diarrhea in a cohort of rural children in India.

A cohort of 452 rural children was followed longitudinally for 13 mo to ascertain the role of HEp-2 cell adherent Escherichia coli and other pathogens in causing acute (less than or equal to 14 d) and persistent (greater than 14 d) diarrhea. Aeromonas, Campylobacter jejuni, E. coli manifesting localized adherence to HEp-2 cells and enterotoxigenic E. coli were significantly associated with acute diarrhea. E. coli strains that exhibit aggregative adherence, so-called enteroaggregative E. coli, a newly-described category of diarrheagenic E. coli distinct from enterotoxigenic, enteroinvasive, enterohemorrhagic, and enteropathogenic E. coli, were found significantly more often in patients with persistent diarrhea (29.5%) than with acute diarrhea (12.8%) (P = .0052) or controls (9.9%) (P = .0006).

Acute Disease↗
PubMed1989

Enteroaggregative Escherichia coli and Salmonella associated with nondysenteric persistent diarrhea.

A hospital-based case-control study including 92 children with diarrhea for longer than 14 days and 92 controls without gastrointestinal symptoms was performed to describe the association between the excretion of enteric pathogens and persistent diarrhea. In patients the most frequently isolated stool pathogens were enteroaggregative Escherichia coli (19.6%), nontyphoidal Salmonella spp. (17.4%), E. coli with diffuse adherence pattern (7.6%), G. lamblia (7.6%) and enterotoxigenic E. coli (5.4%). The excretion rates in patients were significantly greater than in controls only for nontyphoidal Salmonella spp. (P = 0.0006) and enteroaggregative E. coli (P = 0.016).

Diarrhea, Infantile↗
PubMed1989

Role of carboxylesterase in protection against soman toxicity.

Rats were injected intraperitoneally with phenobarbital (PB) and 3-methylcholanthrene (MC) which are microsomal enzyme inducers, and methyl iodide (MeI), cobalt chloride (CoCl2) and tri-o-cresyl phosphate (TOCP) which are inhibitors of the enzymes glutathione transferase, cytochrome (cyt) P-450 and carboxylesterase, respectively, and then challenged with soman (i.p.) to know its LD50. Pretreatment with PB and MC increased and TOCP decreased, whereas MeI as well as CoCl2 did not alter the LD50 value of soman in rats. The 1/2 LD50 dose of soman did not affect the liver microsomal cyt P-450 level, but significantly lowered carboxylesterase (CaE) and cholinesterase (ChE) activities in liver microsomes and in blood plasma. Induction of plasma CaE was more important than microsomal CaE in PB-mediated protection against soman toxicity. Gel filtration of plasma into four protein fractions for their relative soman binding capacity showed that a high-molecular-weight protein fraction (180,000 daltons on SDS-PAGE) which had no CaE activity could bind soman 6 times more than the low-molecular-weight CaE-containing protein fraction (60,000 daltons on SDS-PAGE).

Animals↗
PubMed1989

Methemoglobin toxicity and hematological studies on malaria anti-relapse compound CDRI 80/53 in dogs.

Methemoglobin toxicities of primaquine and compound N1-(3-acetyl-4-5-dihydro-2-furanyl)-N4-(6-methoxy-8-quinolinyl) 1,4-pentanediamine, CDRI Code 80/53, have been compared in beagles. Primaquine administration at 3 mg/kg for 7 days produced significantly high (P less than 0.001) methemoglobinemia and the levels increased 10.55-fold. Compound 80/53 at 3.75 mg/kg x 7 days produced a marginal increase in methemoglobinemia (3.24-fold; P less than 0.02). The methemoglobin formed by primaquine administration was 3.65-fold (P less than 0.001) higher than that formed after administration of compound 80/53. There was no significant change in other hematological parameters and liver function tests.

Aminoquinolines↗