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V Shenoy

Publications and source records attributed to V Shenoy.

At least 19 recordsLinked to original sources
PubMed2001

Pattern Formation in a Thin Solid Film with Interactions.

We investigate a new type of surface instability of a thin elastic film subjected to surface interactions such as van der Waals and electrostatic forces from another solid surface in its vicinity. It is found that a sufficiently soft (shear modulus <10 MPa) and nearly incompressible film deforms to form an undulating pattern without any mass transport. A novel feature is that the characteristic length scale of the pattern is nearly independent of the nature and magnitude of the external force, but varies linearly with the film thickness. These results explain some recent experiments and are applicable to problems such as adhesion and friction at soft solid interfaces, peeling of adhesives, patterning of solid surfaces, etc.

Journal Article↗
PubMed2000

Meniscus instability in a thin elastic film

A new kind of meniscus instability leading to the formation of stationary fingers with a well-defined spacing has been observed in experiments with elastomeric films confined between a plane rigid glass and a thin curved glass plate. The wavelength of the instability increases linearly with the thickness of the confined film, but it is remarkably insensitive to the compliance and the energetics of the system. However, lateral amplitude (length) of the fingers depends on the compliance of the system and on the radius of curvature of the glass plate. A simple linear stability analysis is used to explain the underlying physics and the key observed features of the instability.

Journal Article↗
PubMed1997

Endoscopic ultrasound miniprobe-guided steroid injection for treatment of refractory esophageal strictures.

Local injection of corticosteroids into refractory esophageal strictures to decrease the restenosis rate has been reported. Here we report our efforts in three patients to render the delivery of steroids more precise, by injecting them in the thickest segment of the stricture with the guidance of a high frequency ultrasound miniprobe passed through a regular upper endoscope. Steroid injection under ultrasound miniprobe guidance may be indicated for patients who do not respond to a "blind" steroid injection without miniprobe guidance.

Aged↗
PubMed1997

Absence of bradycardic response to apnea and hypoxia in heart transplant recipients with obstructive sleep apnea.

In patients with obstructive sleep apnea, the vagal stimulation caused by inspiration against the upper airway obstruction results in sinus bradycardia during the apnea followed by a reflex tachycardia at apnea termination. We report on five heart transplant recipients with obstructive sleep apnea who demonstrated no change in baseline heart rate in spite of marked hemoglobin oxygen desaturation, presumably on account of parasympathetic denervation of the allograft. Heart transplant recipients with obstructive sleep apnea may be at an increased risk of development of potentially fatal ventricular arrhythmias if the allograft is unable to respond appropriately to hypoxia. Should cardiac parasympathetic reinnervation occur, prospective polysomnography may be a marker for this process in these patients.

Bradycardia↗
PubMed1996

Characterization of glutaminase in the developing rat small intestine.

As a primary substrate in the small intestine, glutamine is a very important source of energy. Glutaminase (GA) is the enzyme involved in the deamination of glutamine to glutamate, which is utilized for energy production via the TCA cycle. Although the enzymatic activity of GA in the small intestine is known to undergo maturational changes, the tissue localization of the protein and its mRNA, the intracellular processing of this enzyme and levels of its mRNA in the small intestine at different maturational stages have not yet been described. In this study, using immuno-histochemical staining, we confirm previous studies using other techniques that suggested GA is localized in the epithelial layer of the rat small intestine. Some GA is also found in cells of the lamina propria and crypt epithelium. Using in situ hybridization studies, we have corroborated the presence of the protein in the epithelial cells of the villi by localizing the mRNA of this protein to the same layer and its precursor layer in the crypt region. An ontogenic analysis of GA mRNA and protein from rat small intestines, using RNA dot blots, gel blots and protein immunoblotting revealed differences in immunoreactive GA protein and mRNA during maturation. Immunoreactive GA and steady-state levels of GA mRNA increased around the 3rd wk of life, coincident with weaning and the endogenous glucocorticoid surge. Whether these findings have nutritional or pathophysiological implications remains speculative.

Age Factors↗
PubMed1996

Glutamine nutrition and metabolism: where do we go from here ?

Glutamine, a "nonessential" amino acid, is attracting widespread attention because of its relevance to numerous metabolic processes and its potential role in the treatment and prevention of critical illness. In this paper we review some key concepts of glutamine biochemistry, metabolism, and nutrition. We then discuss several studies in the area of glutamine metabolism and nutrition that are primed for further investigation.

Animals↗
PubMed1996

Double-lumen esophagus: formation of a new lumen or septation of the existing one?

Presented here are two cases in which two esophageal lumens were identified at endoscopy. One patient had a history of antireflux surgery and both patients had received esophageal dilations. Both patients have done poorly with standard esophageal dilation and are not considered likely to gain from surgery. The mechanism of formation of the second lumen is not certain in Case 1, but in Case 2 a self-contained perforation appears to be the likely mechanism. There is no clear definition of "double-lumen esophagus" in the literature. The term is used at times interchangeably with esophagogastric fistula. We propose that the phrase "double-lumen esophagus" is a morphologic description and should be used only when the two lumens are of nearly equal diameter. The term "fistula" should be used whenever that is the likely mechanism. Hence, Case 1 of our report is the true double-lumen esophagus, while Case 2 is an esophagogastric fistula. Since patients do poorly with standard dilation, newer endoscopic modalities may have a role in the management of these rare but difficult cases.

Aged↗
PubMed1996

Ontogeny of glutamine synthetase in rat small intestine.

Glutamine synthetase (GS) is a key enzyme involved in the endogenous biosynthesis of glutamine, an amino acid known to be essential for small intestinal metabolism and function. This study describes the ontogeny of rat small intestinal GS from fetal life through adulthood with enzyme activities, protein immunoblotting, and steady state levels of GS mRNA by RNA gel blots and dot blots. Enzyme activities progressively increased from 21 d of fetal life to 32 d postnatally, then decreased in adulthood. The amount of GS immunoreactive protein in the small intestine increased from fetal life to 10-day-old infants and persisted into adulthood. GS mRNA, as quantified by dot blots was highest at 19 d postnatally. The ontogenic changes in rat small intestinal GS appear to correspond temporally with rapid growth and weaning. The steady increase in GS enzyme activity up to 32 d of age with a subsequent drop in adulthood is not paralleled by an increase in GS mRNA or protein. These findings suggest an apparent complex regulation of the enzyme activity at a transcriptional or translational levels.

Aging↗
PubMed1995

Pediatric AIDS.

Explore the source record for details and available documents.

Child↗
PubMed1993

Ontogeny of small intestinal glutaminase and glutamine synthetase in the rat: response to dexamethasone.

The ontogeny of small intestinal glutaminase (GA) and glutamine synthetase (GS) was studied with relation to the maternal administration of dexamethasone (DEX). Pregnant Sprague-Dawley rats were administered 0.2 mg/kg of DEX or saline twice daily on days 19 and 20 of gestation. Activity of GA did not increase from the fetus to the 10-day-old rat; however, GS activity increased 7-fold. DEX induced doubling of GA activity and mRNA, but only a slight increase is GS activity and mRNA was observed in the fetus. GA and GS activities appear to be regulated by different mechanisms.

Animals↗
PubMed1993

Acinetobacter sepsis in neonates.

Twenty-six neonates were diagnosed to have acinetobacter sepsis during 1986-90, representing 6.5% of all cases of bacteriologically proven sepsis. Of these 19 neonates were low birth weight (LBW) 12 were small for gestational age (SGA). Nineteen neonates had early-onset sepsis. The male to female ratio was 9:17. The hematological profile was suggestive of sepsis in 17 cases. All infants had clinical evidence of multi system infection. Eleven babies died; the cases-fatality rate was 42.3%. Only 15/25 culture isolates were sensitive to gentamicin and resistance to other antibiotics was even more frequent. Acinetobacter was cultured from other sites: eye swabs, skin pustules and umbilical catheter tips. Environmental nursery surveillance cultures done during the study period yielded Acinetobacter once from a crib, but no cases of sepsis occurred around that time. The epidemiological features of this organism illustrate the value of vigilance and precautionary measures.

Acinetobacter↗