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R Chhabra

Publications and source records attributed to R Chhabra.

30 records · Page 2Linked to original sources
PubMed1992

Respiratory burst in peritoneal exudate cells in response to a modified tuftsin.

Intraperitoneal administration of tuftsin-M [Thr-Lys-Pro-Arg-NH-(CH2)2-NH-CO-C15H31] to Balb/C mice has been shown to induce a respiratory burst in the peritoneal exudate cells. The macrophages exhibited enhanced levels of O2-, H2O2, NADPH oxidase and myeloperoxidase, but the activities of superoxide dismutase, catalase and glutathione peroxidase remained virtually unchanged. The magnitude of the oxidative burst depended directly on the dose of tuftsin-M; higher activity was observed at higher doses of the peptide. Tuftsin-M enhanced the generation of both O2- and H2O2 under in vitro conditions, as did phorbol myristate acetate. These results suggest that tuftsin-M could enhance non-specific defence against infections by activating the macrophages.

Analysis of Variance↗
PubMed1992

Duodenal atresia presenting as hematemesis in a premature infant with Down syndrome. Case report and review of the literature.

Congenital duodenal obstruction, a common complication of Down syndrome, most often presents as neonatal bilious vomiting. We report the first premature infant with Down syndrome whose duodenal atresia presented with a massive hematemesis secondary to duodenitis. Since a plain radiograph of the abdomen is diagnostic in the case of duodenal obstruction, it should be included in the diagnostic workup of hematemesis in newborn infants.

Down Syndrome↗
PubMed1987

Nonenzymatic synthesis of delta-aminolevulinate (ALA) by cobalt (Co++).

Cobalt, a metal known to modulate the heme biosynthetic enzymes, is shown to be capable of catalysing the formation of ALA through a transamination reaction. The transamination reaction follows a double-displacement reaction kinetics. Further, it has also been shown that the product of the reaction catalysed by cobalt can be used by the enzyme ALA dehydratase as the substrate in the formation of porphobilinogen. The formation of ALA by cobalt can be inhibited by the intermediates of the heme biosynthetic pathway, mainly protoporphyrin. Heme, on the other hand, does not have any effect on the reaction at all concentrations tested.

Alanine↗
PubMed1986

Induction of L-alanine:4,5-dioxovalerate transaminase by phenylhydrazine is associated with depletion of heme level.

The hemin regulation of L-alanine:4,5-dioxovalerate transaminase, the enzyme proposed for an alternate route of delta-aminolevulinic acid (ALA) biosynthesis in mammalian system was studied in different conditions: phenylhydrazine induced anemia, polycythemia by erythropoietin to anemic rats, treatment with cobalt chloride, a porphyrogenic drug. The activity of L- alanine:4,5-dioxovalerate transaminase in liver and kidney is stimulated in phenylhydrazine, whereas, erythropoietin injection to anemic rats prevents such stimulation. Further treatment with cobalt chloride to erythropoietin treated anemic rats stimulates the enzyme activity. Actinomycin D, however, inhibits the stimulation of L-alanine:4,5-dioxovalerate transaminase by phenylhydrazine suggesting that induction is at the level of transcription. Induced level of this enzyme in anemic condition was estimated quantitatively by radial immunodiffusion using antibody raised against L-alanine:4,5-dioxovalerate transaminase. Moreover, our studies reveal that stimulation of L-alanine:4,5-dioxovalerate transaminase in anemic condition is dependent on depletion of heme level. The regulatory role of intracellular heme pool on the induction of this enzyme suggests its physiological importance in heme biosynthesis.

Anemia↗
PubMedDate not supplied

Characterization of specific insulin binding sites in rat testis following induced diabetes and experimental starvation.

The presence of insulin-saturable binding sites in the rat testis have been demonstrated. Employing radioreceptor assay (RRA), the characteristics of insulin binding in both liver and testis of the normal (control) rats have been studied. Crude receptor binding at 37 degrees C after 18-20 hrs of incubation in Tris-HCl buffer at pH-7.5. The binding of 125I-insulin to liver and testis of the experimental rats, rendered diabetic for two months with single parenteral streptozotocin (STZ) administration (65 mg/Kg, BW, ip) was also studied. In the diabetic rats, the insulin binding in liver as compared to the control increased by over 92% (P 0.001); the increase in the binding of 125I-insulin to the testis of the diabetic rats however was not statistically significant. Similarly, insulin binding to the testis did not vary much after 3 days of starvation as against 84% (P 0.001) increase in the insulin binding to the liver of the fasted rats. These results suggest that testicular insulin receptors are similar to those of liver but may have a different physiological control.

Animals↗
PubMedDate not supplied

Use of midline catheters in low birth weight infants.

Prolonged intravenous access is an important consideration in the treatment of premature neonates. Because peripheral intravenous catheters have short dwell times, centrally positioned percutaneous catheters have been used increasingly in neonatal intensive care. Midline catheters are peripherally inserted long catheters advanced only to the proximal portion of a limb or to the neck, with the tip remaining outside the thoracic and abdominal cavities. Midline catheters were placed with use of an innovative technique via a 24-gauge Angiocath catheter (Becton Dickinson, Sandy, Utah). This study compared dwell time and reason for removal of midline catheters with respective data for peripheral intravenous catheters. Dwell time was found to be 9.0 +/- 1.4 days for the midline catheters versus 3.1 +/- 0.5 days for peripheral intravenous catheters placed in the same patients (p < 0.05). No significant complications occurred with the use of midline catheters. These data suggest that midline catheters may be useful in neonates who require a limited duration of intravenous therapy.

Catheterization, Peripheral↗