Search PubMed⌕ Search

Biomedical subjects

S Sharma

Publications and source records attributed to S Sharma.

At least 613 records · Page 34Linked to original sources
PubMed1998

Early diagnosis of mycotic keratitis: predictive value of potassium hydroxide preparation.

Potassium hydroxide (KOH) preparation is an underutilized modality in the diagnosis of mycotic keratitis. We have earlier shown its utility in the diagnosis of Nocardia and Acanthamoeba keratitis. The aim of this study was (i) to evaluate the sensitivity, specificity and predictive value of KOH preparation, and (ii) to compare its efficacy with other methods of corneal scraping examination, for the diagnosis of mycotic keratitis. The study was conducted in two phases. In phase I, randomized corneal scrapings were examined by KOH, Gram's stain, and lactophenol cotton blue (LPCB) in 91 infectious keratitis subjects. In phase II, 53 corneal scrapings were stained with KOH and calcofluor white (CFW), and viewed with bright field (KOH) and fluorescence (CFW) microscopy. The KOH and CFW readings were recorded by an observer masked to the clinical findings and culture results. Nineteen scrapings were examined by two masked observers. In 22 culture positive fungal keratitis patients in phase I, the sensitivity of KOH, Gram's stain, and LPCB methods was 100%, 86.4%, and 77.3%, respectively. In phase II, the specificities of KOH and CFW were identical (83.8%), while the sensitivities were 81.2% and 93.7%, respectively (p = 0.59), in 16 culture positive mycotic keratitis patients. There was no significant difference between the negative and positive predictive values of KOH and CFW. Furthermore, no significant interobserver variability was found in the specificity and sensitivity. The KOH method compares well with other microscopy methods in the diagnosis of keratomycosis and has a definite place in the armamentarium of diagnostic techniques.

Benzenesulfonates↗
PubMed1998

Haematological parameters and HbA2 levels in beta-thalassaemia trait with coincident iron deficiency.

Iron status was estimated in 463 heterozygous beta-thalassaemics to delineate the effect of iron deficiency (ID) on the haematological parameters and expression of HbA2 in these patients. One hundred and twenty six (27.2%) traits had coincident ID. These iron deficient traits had a significantly (p < 0.0002), higher prevalence of anaemia (90.5%) as compared to iron replete traits (71.5%). Mean haemoglobin concentration was significantly lower (p < 0.0001) in beta-thalassaemics with ID (10.7 +/- 1.5) g/al as compared to those without ID (11.6 +/- 1.6 g/dl). Mean MCV and MCH were significantly lowered (p < 0.0001) in patients of beta-thalassaemia trait (BTT) with ID than in these without ID. Mean HbA2 was not significantly different in the two groups of traits and was elevated (> or = 3.5%) in all except one patient. However, mean HbA2/cell was significantly (p < 0.05) lower in traits with ID. The effect of ID in BTT was apparent with significant lowering of haemoglobin concentration and increased prevalence of anaemia. Iron therapy is warranted in iron deficient traits and would help in significantly raising their haemoglobin concentration. Elevation in HbA2 values was striking and could be used with reliability for diagnosis of BTT even in the presence of ID.

Anemia, Iron-Deficiency↗
PubMed1998

Effects of spinal anaesthesia on metabolic processes.

A study conducted at P.G.I., Chandigarh to find out the effect of spinal anaesthesia on arterial blood gases, blood glucose, and pyruvate-lactate during spinal anaesthesia. All patients received night sedation of oral diazepam in dose of 0.2 mg/kg body weight. No narcotic/antisialogogue premedication was given to any patient. All patients received spinal anaesthesia with 5% lignocaine (hyperbaric), in lateral position. All patients received normal saline intravenously as a maintenance fluid. Blood samples for the measurement of blood pyruvate, lactate levels and arterial blood gas analysis were collected preoperatively, 10 minutes after the administration of spinal anaesthesia after fixation of drug, and half hour after the end of operative procedure. Even though there was continued rise in blood sugar levels intraoperatively, which persisted in postoperative period, the values were within normal clinical range. Blood lactate levels and blood pyruvate levels remained unchanged. Hypocapnoea observed intra-operatively in our report is attributed to hyperventilation. There was 12.44% fall in bicarbonate level. (P > .001) which even though statistically significant did not alter the pH. We conclude that spinal anaesthesia up to T8 level does not affect the metabolic processes.

Acid-Base Equilibrium↗
PubMed1997

The N-methyl-D-aspartate (NMDA) receptor is postsynaptic to substance P-containing axon terminals in the rat superficial dorsal horn.

The N-methyl-D-aspartate (NMDA) receptor is thought to mediate the postsynaptic effects of excitatory amino acids released from primary afferent terminals in the superficial layers of the dorsal horn of the spinal cord where synergistic associations with substance P (SP) have been implicated in the production of hyperalgesia. We examined the electron microscopic dual immunocytochemical localization of SP and the R1 subunit of the NMDA receptor (NMDAR1) in this region to determine the cellular basis for interactions between SP and NMDA receptor ligands. Of 971 profiles immunolabeled for NMDAR1, 40% were dendrites and the remainder were primarily unmyelinated axons and astrocytic processes. In dendrites, NMDAR1-like immunoreactivity (NMDAR1-LI) was associated with synaptic and non-synaptic portions of the plasma membrane, as well as intracellular membranes including smooth endoplasmic reticulum. These NMDAR1-labeled dendrites received synaptic input from unlabeled terminals and from terminals containing SP and/or NMDAR1-LI and they occasionally (25/389) also contained SP. In contrast, of 540 SP-immunoreactive profiles, 60% were axon terminals and the majority (252/324) of these SP-labeled terminals were presynaptic to NMDAR1-containing dendrites. These results provide anatomical evidence that the synergistic nociceptive effects of SP and NMDA ligands are attributed mainly to dual modulation of the activity of single dendritic targets in the dorsal horn of the spinal cord. They also suggest that activation of NMDA receptors may also play a role in the modulation of SP neurons, presynaptic release of SP or other neurotransmitters, and in glial function in the dorsal horn.

Animals↗
PubMed1997

Cocaine inhibits human endothelial cell IL-8 production: the role of transforming growth factor-beta.

Cocaine use is associated with modulation of a broad range of biological functions including the capacity to influence cytokine production in murine and human immunoeffector cells. Little is known, however, regarding the effects of cocaine on endothelial cell cytokine production. Because the vascular endothelium actively participates in acute and chronic inflammatory responses and interleukin-8 (IL-8) is one of the key cytokines involved in the inflammatory process, modification of the production of IL-8 by vascular endothelial cells may interfere with the host response to infection or tissue injury. We investigated the effect of cocaine on endothelial cell IL-8 production. Conditioned supernatant from EA.hy 926 cells were evaluated by ELISA following in vitro cocaine exposure. Cocaine decreased IL-8 production in a dose-responsive manner, and this reduction correlated with down-regulation of IL-8 mRNA expression. Cocaine also increased the production of TGF-beta by EA.hy 926 cells and anti-TGF-beta abrogated the cocaine-mediated decrement of IL-8 production, indicating that cocaine down-regulates endothelial IL-8 production by increasing TGF-beta. Our findings suggest that the immunomodulatory effects of cocaine may be mediated, in part, by modification of endothelial-derived cytokine production.

Cell Line↗
PubMed1997

The swiss cheese mutant causes glial hyperwrapping and brain degeneration in Drosophila.

Swiss cheese (sws) mutant flies develop normally during larval life but show age-dependent neurodegeneration in the pupa and adult and have reduced life span. In late pupae, glial processes form abnormal, multilayered wrappings around neurons and axons. Degeneration first becomes evident in young flies as apoptosis in single scattered cells in the CNS, but later it becomes severe and widespread. In the adult, the number of glial wrappings increases with age. The sws gene is expressed in neurons in the brain cortex. The conceptual 1425 amino acid protein shows two domains with homology to the regulatory subunits of protein kinase A and to conceptual proteins of yet unknown function in yeast, worm, and human. Sequencing of two sws alleles shows amino acid substitutions in these two conserved domains. It is suggested that the novel SWS protein plays a role in a signaling mechanism between neurons and glia that regulates glial wrapping during development of the adult brain.

Amino Acid Sequence↗
PubMed1997

Noninfectious virus-like particles produced by Moloney murine leukemia virus-based retrovirus packaging cells deficient in viral envelope become infectious in the presence of lipofection reagents.

Retrovirus packaging cell lines expressing the Moloney murine leukemia virus gag and pol genes but lacking virus envelope genes produce virus-like particles constitutively, whether or not they express a transcript from an integrated retroviral provirus. In the absence of a proviral transcript, the assembled particles contain processed gag and reverse transcriptase, and particles made by cells expressing an integrated lacZ provirus also contain viral RNA. The virus-like particles from both cell types are enveloped and are secreted/budded into the extracellular space but are noninfectious. Their physicochemical properties are similar to those of mature retroviral particles. The noninfectious gag pol RNA particles can readily be made infectious by the addition of lipofection reagents to produce preparations with titers of up to 10(5) colony-forming units per ml.

Cell Line↗
PubMed1997

Maternal care, hippocampal glucocorticoid receptors, and hypothalamic-pituitary-adrenal responses to stress.

Variations in maternal care affect the development of individual differences in neuroendocrine responses to stress in rats. As adults, the offspring of mothers that exhibited more licking and grooming of pups during the first 10 days of life showed reduced plasma adrenocorticotropic hormone and corticosterone responses to acute stress, increased hippocampal glucocorticoid receptor messenger RNA expression, enhanced glucocorticoid feedback sensitivity, and decreased levels of hypothalamic corticotropin-releasing hormone messenger RNA. Each measure was significantly correlated with the frequency of maternal licking and grooming (all r's > -0.6). These findings suggest that maternal behavior serves to "program" hypothalamic-pituitary-adrenal responses to stress in the offspring.

Adrenocorticotropic Hormone↗
PubMed1997

Expression of individual members of a tRNA(Gly)1 multigene family in vivo follows the same pattern as in vitro.

Individual members of a tRNA(Gly)1 multigene family from Bombyx mori are transcribed to different levels in vitro in homologous nuclear extracts but their transcription status in vivo is not known. Two sets of tRNA(Gly)1 belonging to the extreme groups of highly transcribed and barely transcribed copies have been examined for their expression patterns in vivo in B. mori-derived cell lines following transfection. We have developed a sensitive and reliable method for directly quantifying the transcription levels of transfecting tRNA genes without relying on the biological activity of the transcript. The strategy involved the insertion of synthetic oligodeoxyribonucleotide sequences into the coding region of the transfecting gene and monitoring the transcripts in an RNase protection assay using an antisense probe that clearly distinguished them from the endogenous tRNAs. The oligonucleotide insertion did not significantly affect the transcriptional status of the genes, even though the distance between the A and B boxes was enhanced by 10-15 nt. In vivo also the transcription of tRNA(Gly)1 reached very high levels, whereas the transcripts arising from tRNA(Gly)1-6:7 accounted for only 2-5% of the former, closely resembling the transcription patterns in vitro. These individual gene copies having identical coding sequences and consequently the same internal conserved regions, differed only in their flanking sequences which modulate their transcription levels.

Animals↗