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Biomedical subjects

S Gupta

Publications and source records attributed to S Gupta.

At least 991 records · Page 55Linked to original sources
PubMed1994

Perforated typhoid enteritis in children.

A prospective study of 65 patients with perforated typhoid enteritis managed operatively over a 3 year period at a university hospital is presented. There were 45 males and 20 females with ages ranging from 5 to 15 years. Presenting symptoms were fever, abdominal pain, vomiting and either diarrhoea or constipation. All the patients were subjected to surgery and 56 (86%) underwent two-layer bowel closure after freshening of ulcer margins. The overall mortality rate in this study was 20% and was adversely influenced by the increasing duration of perforation, presence of shock and faecal peritonitis. Early surgery after prompt and adequate resuscitation is life saving. However, prevention of typhoid fever by providing safe drinking water and better sanitary conditions appears to offer the best chance of decreasing the high rates of mortality and morbidity of this deadly disease.

Adolescent↗
PubMed1994

Leiomyosarcoma in leiomyomatosis of the small intestine.

Multiple leiomyomata of the small intestine are rare. We report one such case where a leiomyosarcoma had arisen from a leiomyoma in the small intestine 8 years after presentation. The possible origin of the leiomyomata is discussed and it is concluded that small intestinal leiomyomatosis should be regarded as a premalignant condition.

Adult↗
PubMed1994

Role of endothelium-derived nitric oxide in stimulation of Na(+)-K(+)-ATPase activity by endothelin in rabbit aorta.

An endothelium-derived factor with the properties of nitric oxide (NO) has recently been implicated in the regulation of basal Na(+)-K(+)-adenosinetriphosphatase (ATPase) activity in vascular smooth muscle. To determine whether this factor also plays a role in the stimulation of ouabain-sensitive (OS) 86Rb uptake by specific agonists, studies were carried out using rabbit aortic rings. In endothelium-intact rings incubated for 3 h with Krebs-Henseleit solution containing 5.5 mM glucose, endothelin (ET) caused a concentration-dependent increase in OS 86Rb uptake (maximal increase = 205%, with 100 nM ET). Incubation with phenylephrine (Phe; 0.1 and 1 microM) or phorbol 12,13-dibutyrate (PDBu; 0.1 microM), under the same conditions, increased OS 86Rb uptake by 128, 144, and 140%, respectively. Removal of endothelium before incubation decreased the ability of ET to stimulate OS 86Rb uptake by 38-45%, but it did not diminish the stimulation of OS 86Rb uptake by Phe or PDBu. An increase in the concentration of glucose from 5.5 to 44 mM diminished ET-stimulated OS 86Rb uptake by 50% in endothelium-intact rings but had no effect on Phe- or PDBu-induced increases in OS 86Rb uptake. Addition of the NO synthase inhibitor NG-monomethyl-L-arginine (L-NMMA; 0.3 mM) to the medium decreased ET-stimulated OS 86Rb uptake by 40%. Guanosine 3',5'-cyclic monophophate (cGMP) formation in endothelium-intact rings was also increased (65%) by ET but not by Phe or PDBu. The increase in cGMP by ET was totally inhibited by L-NMMA or endothelium denudation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Stimulation of vascular Na(+)-K(+)-ATPase activity by nitric oxide: a cGMP-independent effect.

An endothelium-derived factor with the properties of nitric oxide (NO) has been implicated in the regulation of Na(+)-K(+)-adenosinetriphosphatase (ATPase) activity in vascular smooth muscle. To examine this phenomenon further and to explore its modulation by guanosine 3',5'-cyclic monophosphate (cGMP), studies were carried out in the isolated rabbit aorta. Incubation of endothelium-denuded rings with NO (1 microM) or sodium nitroprusside (SNP, 10 microM) caused a time-dependent increase in ouabain-sensitive (OS) 86Rb uptake with the maximal stimulation (approximately 170%) seen after 20 min. In contrast, increases in cGMP concentration caused by NO and SNP (40- and 20-fold increases, respectively) were transient, with peak values observed after 2 min and significantly lower values by 10 min. The ability of NO or SNP to increase OS Rb uptake in endothelium-denuded rings was not mimicked by incubation with 8-bromo- or dibutyryl-cGMP or increases in cGMP caused by treatment with the phosphodiesterase inhibitor isobutylmethylxanthine. Depletion of intracellular cGMP levels by the guanylate cyclase inhibitor LY83583 also did not alter OS Rb uptake. SNP-stimulated OS Rb uptake was not inhibited by LY83583 in endothelium-denuded rings; however, it was completely prevented by the Na(+)-H+ exchange inhibitors amiloride and ethylisopropylamiloride. The results suggest that NO stimulates Na(+)-K(+)-ATPase activity in rabbit aorta by a mechanism independent of its ability to increase the intracellular cGMP concentration. They also suggest that NO may stimulate Na(+)-K(+)-ATPase activity secondary to increases in Na(+)-H+ exchange.

Amiloride↗
PubMed1994

Occurrence of necrotizing enterocolitis may be dependent on patterns of bacterial adherence and intestinal colonization: studies in Caco-2 tissue culture and weanling rabbit models.

Necrotizing enterocolitis (NEC) is one of the leading causes of death in neonatal intensive care units. The underlying pathophysiology of NEC is poorly defined, although there is a suggestion that bacterial agents play an important role in the process. In this study, we evaluated bacterial isolates from 17 NEC cases and matched asymptomatic control infants. Isolates from NEC patients were no more likely than control isolates to be adherent to enterocytes, as assessed by a Caco-2 cell tissue culture model. Adherent Escherichia coli isolates, from both NEC cases and controls, were able to cause pathologic changes typical of NEC in a weanling rabbit ileal loop model. Adherence of E. coli strains to Caco-2 cells, and subsequent production of disease in weanling rabbits, could be blocked by coinfection with Gram-positive isolates from control children. In contrast, in three of four instances, adherent E. coli from NEC cases retained their adherence and caused illness in rabbits when coinfected with Gram-positive isolates from the homologous child. Our data suggest that patterns of intestinal adherence, as influenced by the underlying intestinal microbial ecology, play a role in the pathophysiology of NEC.

Animals↗
PubMed1994

Butyrate synchronization of hepatocytes: modulation of cycling and cell cycle regulated gene expression.

To develop a model for studies of liver growth control, we characterized cell cycle synchronization of liver-derived cells with sodium butyrate. Exposure of cultured HTC (rat hepatoma) cells to 5 mM butyrate arrested cell growth in a reversible manner. Flow cytometric analysis revealed that butyrate-treated HTC cells were restricted in G0/G1, as well as S/G2M phases. After release from butyrate arrest, HTC cells underwent synchronous cycles of DNA synthesis and transited through S phase. Inhibition of cell growth by butyrate was associated with a complex pattern of cell cycle regulated gene expression, including a decoupling of c-fos and c-jun gene expression. Transcription of c-fos, as well as c-jun increased with butyrate arrest, whereas steady rate mRNA levels of c-jun only were increased, suggesting additional regulation of c-fos. In addition, butyrate-arrested cells exhibited a transcriptionally determined accumulation of H3 histone, C-Ha-ras and ornithine decarboxylase mRNAs, suggesting that cell cycle-related check points following the onset of S phase were modulated. An increase in c-myc mRNA levels in butyrate-arrested cells was post-transcriptionally regulated. After release from butyrate-arrest, the abundance of immediate early, as well as S phase regulated, gene expression changed coordinately with S phase cell transitions. Thus, exposure of HTC cells to butyrate modulates cell cycle regulated gene expression, inhibits cycling, and results in accumulation of cells in specific compartments. Synchronization of liver cells with butyrate should, therefore, provide a useful model for defining cell cycle-related events in response to various mitogenic stimuli.

Animals↗
PubMed1994

Clozapine treatment of polydipsia.

A patient with refractory chronic schizophrenia having severe polydipsia and hyponatremia was treated with clozapine. There followed a dramatic improvement in the polydipsia and correction of the hyponatremia. This improvement has been sustained throughout a 6-month follow-up.

Adult↗
PubMed1994

Risperidone: review of its pharmacology and therapeutic use in schizophrenia.

The discovery of antipsychotic medications has revolutionized the treatment of schizophrenia and other psychotic disorders. However, side effects such as extrapyramidal symptoms (EPS) and tardive dyskinesia have been limiting factors in treatment. The introduction of atypical drugs such as clozapine and risperidone has ushered in a new era. This article provides an overview of the pharmacology, efficacy, and techniques for the clinical use of risperidone, which has recently become available.

Antipsychotic Agents↗
PubMed1994

Characterization and enrichment of fetal rat hepatoblasts by immunoadsorption ("panning") and fluorescence-activated cell sorting.

We developed methods for enriching fetal hepatoblasts by combining panning and multiparametric fluorescence-activated cell sorting. In unpurified, dissociated fetal liver cell suspensions of embryonic age day 15, 3.2% +/- 1.3% and 2.5% +/- 0.7% cells expressed albumin and alpha-fetoprotein, respectively. The remainder exhibited a hemopoietic, endothelial or stromal cell phenotype. Cells were panned first with an antibody to red blood cells to remove erythroid cells and then with monoclonal antibodies OX-43/OX-44 to remove hemopoietic and endothelial cells. This procedure eliminated 84% of fetal hepatic cells, with enrichment of the remainder for albumin or alpha-fetoprotein expression (up to sixfold increase). Flow cytometric analysis of unlabeled cells revealed two populations, which differed in granularity and autofluorescence. After panning, fluorescence-activated cell sorting for agranular cells yielded OX-43/44-positive cells that were essentially all hemopoietic precursor cells or OX-43/44-negative cells that were mostly hemopoietic precursor cells, along with 3.0% +/- 0.7% alpha-fetoprotein-positive cells. In contrast, sorting for granular, OX-43/44-negative cells enriched for predominantly alpha-fetoprotein-positive, parenchymal precursor cells (75.1% +/- 4.7%). Multiparametric flow cytometric analysis of the expression of an oval cell antigen, OC.3, which is a bile duct and putative liver stem cell marker, showed that most OC.3-positive cells coexpressed OX-43/OX-44 and morphologically were hemopoietic precursor cells. However, approximately 30% of the OX-43/44-negative, granular cells expressed OC.3. Although the physiological significance of OC.3-positive hepatoblasts remains to be determined, the ability to isolate distinct liver cell populations by means of fluorescence-activated cell sorting should facilitate further studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Albumins↗
PubMed1994

Desynchronization of circadian rhythms in a group of shift working nurses: effects of pattern of shift rotation.

Sixteen shift working nurses, (eight senior and eight junior nurses) working in a Government hospital and five diurnally active healthy human subjects participated in the present study. The subjects self-measured oral temperature, heart rate, subjective fatigue, subjective drowsiness, finger counting speed and random number addition speed 4-6 times a day for about 3 weeks. Power spectrum and cosinor techniques were employed to analyze individual and group time series. The frequencies of circadian rhythm detection, by cosinor rhythmometry as a group phenomenon, were of 100%, 38%, and 21% in control subjects, senior nurses and junior nurses, respectively. These results were also complemented by power spectrum analysis. Desynchronization of circadian rhythms in several variables was documented in shift workers. The extent of desynchronization was more prominent among junior nurses as compared with their senior counterparts. It was also noticed that in several variables frequency multiplication of circadian rhythm took place among shift workers. The differences in terms of shift-work effects ranging from rhythm desynchronization to frequency multiplication between senior and junior nurses could be ascribed to the pattern of shift rotation employed.

Adult↗