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Biomedical subjects

N Singh

Publications and source records attributed to N Singh.

At least 469 records · Page 26Linked to original sources
PubMed1992

Is a full team required for emergency management of pediatric trauma?

Pediatric trauma centers often do not meet the guidelines requiring a trauma team as recommended by the American Academy of Pediatrics (AAP). We reviewed our experience with a team consisting of a pediatric emergency physician, resident, nurse, and respiratory therapist. The surgical and pediatric critical care residents and staff were available within 5 minutes. We conducted a retrospective chart review of 146 patients (aged 8.1 +/- 4.8 years) between 1987 and 1989, with Injury Severity Scores (ISS) greater than or equal to 16 or admitted to the pediatric critical care unit. The time of presentation, surgical services consulted, and the nature of the injury were obtained from chart review. The Pediatric Trauma Score (PTS), the Revised Trauma Score (RTS), the Injury Severity Score (ISS), Glasgow Coma Scale (GCS) score, and Pediatric Risk of Mortality (PRISM) were used to determine the severity of insult and physiologic derangement on admission. The Modified Injury Severity Score (MISS) was determined and the Delta score for Disability Assessment was assigned at discharge. The Delta score was also determined at 3-month intervals up to one year. The probability of survival (Ps) was calculated, using the ISS and RTS. The Z statistic for this group of patients was then determined, using the Major Trauma Outcome Study (MTOS) methodology. The percentages of patients who were normal, disabled, and dead were 61%, 31.5%, and 7.5%, respectively, at 6 months follow-up. Eleven deaths were expected based on PRISM and TRISS analysis. Our mortality and morbidity figures were comparable with those of centers with teams based on AAP guidelines.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Phosphoenolpyruvate carboxylase activity and concentration in the endosperm of developing and germinating castor oil seeds.

Monospecific polyclonal antibodies against maize leaf phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) were utilized to examine the subunit composition and developmental profile of endosperm PEPC in developing and germinating castor oil seeds (Ricinus communis L. cv Baker 296). PEPC from developing endosperm consists of a single type of 100-kilodalton subunit, whereas the enzyme from 2- to 5-day germinated endosperm appears to contain equal proportions of immunologically related 103- and 108-kilodalton subunits. The maximal activity of PEPC in developing endosperms (2.67 micromoles oxaloacetate produced per minute per gram fresh weight) is approximately 20-fold and threefold greater than that of fully mature (dry seed) and germinating endosperms, respectively. The most significant increase in the activity and concentration of endosperm PEPC occurs during the middle cotyledon to full cotyledon stage of seed development; this period coincides with the most active phase of storage oil accumulation by ripening castor oil seeds. The data are compatible with the recent proposal (RG Smith, DA Gauthier, DT Dennis, DH Turpin [1992] Plant Physiol 1233-1238) that PEPC plays a fundamental role in vivo in the cytosolic production of an important substrate (malate) for fatty acid biosynthesis by developing castor oil seed leucoplasts. Immediately following seed imbibition, PEPC activity and concentration increase in parallel, with the greatest levels attained by the third day of germination. It is suggested that during this early phase of seed germination PEPC has a critical function to build up cellular dicarboxylic acid pools required to initiate significant activities of both the tricarboxylic acid and glyoxylate cycles.

Journal Article↗
PubMed1992

Responses of limbic and extrapyramidal neurotensin systems to stimulants of abuse. Involvement of dopaminergic mechanisms.

In summary, we have observed that drugs of abuse, which can cause schizophrenia-like paranoia, alter striatal and accumbens NT systems in a similar, dramatic fashion. The NT responses to these drugs, in particular METH, are mediated by activation of DA D1 receptors. We have observed that NMDA-type glutamate receptors are essential for the D1-NT interaction. NMDA receptors are selective, since they do not contribute to the antagonistic effects of DA D2 receptors on NT activity. This observation suggests that NT responses to D1 and D2 regulation are mediated through separate and distinct mechanisms. Finally, we found that the presence of METH dramatically reduces striatal NT release, which most likely leads to NT accumulation in nerve terminals and the observed increase in NT tissue level. The blockade of NT release by a psychotogenic drug, such as METH, is consistent with the hypothesis that NT has antipsychotic activity and a decrease in its release may contribute to some forms of schizophrenia similar to that caused by intense use of the stimulants of abuse.

Animals↗
PubMed1992

Histoenzymological demonstration of glycerol-3-phosphate dehydrogenase and succinate dehydrogenase in the telencephalic nuclei and fibre tracts of hillstream cyprinoid, Barilius bendelisis (Hamilton).

The authors studied the regional localization of two dehydrogenases--glycerol-3-phosphate dehydrogenase and succinate dehydrogenase--in the telencephalic nuclei and fibre tracts of Barilius bendelisis by histoenzymological methods. The activity of these dehydrogenases varied from moderately positive to strongly positive in the nuclear areas and from intensely to strongly positive in the fibre tracts, except those related to the olfactory tubercle. G3PD appears to play an important role in the biosyntheses of phospholipids and to form a link between glycolysis and the pathway of the hexose-monophosphate shunt, in addition to its usual role in the degradation of glucose, along with other dehydrogenases, including succinate dehydrogenase.

Animals↗
PubMed1992

Studies of the histoenzymological mapping of acid and alkaline phosphatases in the hindbrain of Barilius bendelisis (Hamilton).

The regional localization of acid and alkaline phosphatase (EC 3.1.3.2. and 3.1.3.1. respectively), determined histoenzymologically, is described in the cerebellum and medulla oblongata of Barilius bendelisis (Hamilton). Acid phosphatase activity in nuclear areas was observed to be moderately positive, whereas alkaline phosphatase activity varied from weak to strongly positive. The localization pattern of these enzymes in the fibre tracts differed. One interesting finding in this study was that the Purkinje cells in the cerebellum and the Mauthner cells in the medulla oblongata contained these enzymes in a high concentration. The contrasting cytological distribution patterns of the two enzymes indicate that their roles in the neurons and fibre tracts are probably different.

Acid Phosphatase↗
PubMed1992

Correlation of plasma color index with serum bilirubin in neonatal hyperbilirubinemia.

In this study, a simple method was evaluated for serum bilirubin estimation in neonates. The color of plasma was compared with various dilutions of potassium dichromate. Readings were then compared with serum bilirubin levels obtained by diazo reaction. The coefficient of correlation (r = 0.7947) between the two was statistically significant. It is concluded that the color index provides reliable estimates of serum bilirubin levels.

Bilirubin↗
PubMed1992

Cimetidine therapy and duodenal candidiasis: role in healing process.

Patients with Candida colonization and invasion were studied in 20 duodenal ulcer (DU) patients, 10 non-ulcer dyspepsia (NUD) cases and 10 controls with non-gastroenterological disorders. Of 20 DU patients, Candida albicans was cultured from duodenal aspirates of 6 (30%) DU patients and pseudohyphae, indicating invasive form, were present in two (10%) prior to treatment. NUD patients and controls had positive Candida culture in 3 (30%) and 1 (10%) cases respectively; pseudohyphae were found in none. Six DU patients (30%) failed to heal with 4 weeks of cimetidine therapy; all six showed invasion of duodenal ulcer mucosa with Candida on histology. The pseudohyphae form of Candida was always found to be associated with non-healing of DU. Candidal invasion is associated with failure to respond to, H2-receptor antagonist therapy.

Candidiasis↗
PubMed1992

Erythrocytic glucose-6-phosphate dehydrogenase deficiency in the Bania community of Punjab.

Five hundred members belonging to the Bania community of Punjab were screened for erythrocytic glucose-6-phosphate dehydrogenase (G-6-PD) deficiency. The incidence of enzyme deficiency in males was 2.84 per cent and in females 2.75 per cent, with an overall incidence of 2.80 per cent. No correlation between age and G-6-PD deficiency was found. The mean values for haemoglobin and haematocrit did not differ significantly in the normal and deficient subjects. Study of the deficiency pattern amongst family members of the enzyme deficient subjects confirmed the X-linked inheritance of G-6-PD deficiency.

Age Factors↗
PubMed1991

Transduction of enzyme-ligand binding energy into catalytic driving force.

We propose a testable general mechanism by which ligand binding energy can be used to drive a catalytic step in an enzyme catalyzed reaction or to do other forms of work involving protein molecules. This energy transduction theory is based on our finding of the widespread occurrence of ligand binding-induced protein macrostate interconversions each having a large invariant delta H0 accompanied by a small but highly variable delta G0. This phenomenon, which can be recognized by the large delta Cp0's it generates, can provide the necessary energy input step but is not in itself sufficient to constitute a workable transduction mechanism. A viable mechanism requires the additional presence of an 'energy transmission step' which is terminated to trigger the 'power' stroke at a precise location on the reaction coordinate, followed by an energetically inexpensive 'return' step to restore the machine to its initial conditions. In the model we propose here, these additional steps are provided by the existence of ligand inducible 2-state transitions in the free enzyme and in each of the enzyme complexes that occur along the reaction coordinate, and by the selective blocking of certain of these interconversions by high energetic barriers. We provide direct experimental evidence supporting the facts that these additional mechanistic components do exist and that the liver glutamate dehydrogenase reaction is indeed driven by just such machinery. We describe some aspects of the chemical nature of these transitions, and evidence for their occurrence in other systems.

Animals↗
PubMed1991

Enhanced poly ADP-ribosylation in human leukemia lymphocytes and ovarian cancers.

Freshly isolated human peripheral blood lymphocytes from leukemia (AML, ALL, CML) subjects, showed a 2.5-3.5-fold increase in the poly ADPR transferase (poly ADPRT) activity whereas ovarian cancers showed a 2-fold increase. This was accompanied by a drop in NAD levels of 45%-63% in leukemia cells and 40% in ovarian cancers. Tumour promoters phorbol-12-myristate-13-acetate (PMA) and mezerein produced an increase in poly ADPRT activity in both normal and CML lymphocytes, but the increase was more marked in the case of normals. This was accompanied by a drop in NAD levels. The results presented show a marked increase in poly ADP-ribosylation in malignant cells but normal lymphocytes showed a greater response to tumour promoters as compared to CML lymphocytes.

Adolescent↗
PubMed1991

Effect of automobile exhaust on the distribution of trace elements and its modulation following Fe, Cu, and Zn supplementation.

The effect of automobile exhaust on the distribution of trace elements with special reference to Pb and its modulation following Cu, Zn, and Fe supplementation, in mouse organs, has been studied using Energy Dispersive X-ray Fluorescence technique. Seven elements, namely K, Fe, Cu, Zn, Br, Rb, and Pb, were detected in all the organs. The maximum concentration of Pb was found in lungs followed by that in liver and kidney. The effect of automobile exhaust was found to be significant on the concentrations of Fe and Pb; their concentrations were found to increase in all the organs. However, the concentrations of Cu and Zn were found to be decreased significantly in the liver. In the animals given Fe, Cu, or Zn supplementation along with motor exhaust, the percentage change in the concentration of Pb in lungs was decreased, and that of Fe was increased significantly. In kidney, no significant change was observed for the animals given Cu and Zn, whereas for animals given Fe, the level of Pb decreased significantly. In liver, the reduction in the level of Zn in the exhaust-exposed animals was made up and the level of Pb was reduced following Zn supplementation. These results clearly indicate that Fe and Zn play an important role in Pb metabolism and tend to lower the absorption of Pb. The effect of Fe is more pronounced than that of Zn, whereas the effect of Cu seems to be insignificant.

Administration, Inhalation↗
PubMed1991

An experimental evaluation of possible teratogenic potential in Boerhaavia diffusa in Albino rats.

The present study was undertaken to evaluate any possibility of teratogenic effects in Boerhaavia diffusa (Punarnava), a widely used herbal medicine for renal and urinary tract diseases by Ayurvedic physicians in India. The ethanolic extract of Boerhaavia diffusa (BDE) was administered daily in a dose of 250 mg/kg, body weight p.o., to pregnant albino female rats during the entire period of gestation. BDE was found to be devoid of any teratogenic effect as litter size and survival rate of foetuses were the same as for the normal control group and no foetal anomaly could be detected.

Animals↗
PubMed1991

Invasive aspergillosis in AIDS.

Invasive pulmonary aspergillosis was diagnosed in two patients with HIV infection, one with prolonged neutropenia and another receiving corticosteroid therapy. We found 17 additional cases in the literature. A known predisposing risk factor for invasive aspergillosis, eg, neutropenia, corticosteroid use, or intravenous drug abuse, was present in 79% of the cases. That the known immunologic defect of AIDS is not a major host defense against Aspergillus is supported by the empiric observation of the relative rarity of aspergillosis in patients with AIDS. The lung was the most common site of Aspergillus infection (75%), and transbronchial biopsy is diagnostically useful. Central nervous system involvement was seen in 55% and appears to be more frequent in HIV-infected patients than in other immunosuppressed patients with invasive aspergillosis. Prognosis is grim. Despite early institution of amphotericin B therapy in a few cases, the disease was uniformly fatal. Efficacy of therapy with amphotericin B plus rifampin or itraconazole remains to be evaluated. We conclude that aspergillosis is not an AIDS-related opportunistic infection.

Acquired Immunodeficiency Syndrome↗