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Biomedical subjects

P Sharma

Publications and source records attributed to P Sharma.

At least 361 records · Page 20Linked to original sources
PubMed1991

Correlation of zymodeme patterns, virulence & drug sensitivity of Trichomonas vaginalis isolates from women.

Characterization of T. vaginalis strains isolated from symptomatic and asymptomatic subjects was done by isoenzyme analysis. The pathogenicity of these isolates was checked in mouse model and in vivo drug susceptibility was determined. The isolates from symptomatic and asymptomatic individuals could not be grouped on the basis of isoenzyme analysis alone. All the strains except one, were pathogenic for mice, and metronidazole (50 mg/kg body weight) was effective in protecting the mice from T. vaginalis infection.

Adult↗
PubMed1990

TPA and resiniferatoxin-mediated activation of NADPH-oxidase. A possible role for Rx-kinase augmentation of PKC.

The non-tumour promoting irritant, resiniferatoxin, was capable of activating the NADPH-oxidase respiratory burst of starch-elicited, but not resident mouse peritoneal macrophages in vitro. Unlike TPA, the response was synergised by incubation with zymosan. The Rx-stimulated NADPH-oxidase activity in a cell-free assay was selectively enhanced in the presence of exogenous Rx-kinase rather than PKC and in the absence of Ca2+. Since resiniferatoxin is a poor activator of PKC, it is probable that the Ca2(+)-independent Rx-kinase plays a role in activation of the macrophage respiratory burst following stimulation by zymosan.

Animals↗
PubMed1990

Ring chromosomes in hypodiploid and hypotetraploid clones from an elderly patient with plasma cell leukemia.

We describe a 77-year-old woman who had with what appears to be the first case of plasma cell leukemia (PCL) with a ring chromosome of variable size. Of the three clones evident, two of them were abnormal: a 41,X,-X hypodiploid clone with rings of two different sizes, and a 81-82,XX hypotetraploid clone with a double-sized dicentric ring or variable double rings. Additional structural and numerical abnormalities included a 14q+ marker, deletions of two chromosomes 1 and monosomies 8 and 13, all previously reported in PCLs. Ring chromosomes have been associated with a poor prognosis, especially in elderly patients. The patient declined active treatment and died within 4 weeks of diagnosis.

Aged↗
PubMed1990

Effects of ethanol in acute carbon monoxide poisoning.

The combined effects of ethyl alcohol (ETOH) intoxication and carbon monoxide (CO) poisoning were studied in the Levine-prepared rat. Infusion or injection of ETOH before and during 90 min of CO exposure to blood levels 2-4 times those considered legally drunk in humans, increased survival at 2400 ppm, and extended the tolerance time at 2400 ppm and 3000 ppm. CO exposure produced the usual hypothermia, hypotension and hemoconcentration; these responses were not altered by concurrent ETOH treatment. Blood ETOH concentration was increased in the presence of CO, and this was related to CO concentration. Although ETOH did not alter the average degree of hypoglycemia seen during the later stages of CO exposure, rats with the highest ETOH concentration tended to have the lowest blood glucose. ETOH increased the magnitude of the hyperglycemic rebound during recovery from exposure to both CO concentrations. Moreover, the magnitude of the recovery hyperglycemic rebound was directly related to the magnitude of the previous hypoglycemia, at both CO concentrations, with or without ETOH. Rats dying during exposure to both CO concentrations were severely hypoglycemic, whereas survivors maintained more or less normal blood glucose concentrations. The results suggest that the presence of ETOH during CO poisoning increases blood ETOH to higher than expected levels and provides a significant degree of survival protection.

Alcoholic Intoxication↗
PubMed1990

A spectrophotometric method for the estimation of polymer-supported sulfhydryl groups.

A sensitive and simple method is described for the quantitative determination of free sulfhydryl (-SH) groups on polymer supports. The method includes the reaction of 4,4'-dimethoxytrityloxy-S-(2-thio-5-nitropyridyl)-2-mercapto ethane (DTNPME) with polymer-supported sulfhydryl groups. After removal of excess reagent through washing, a weighed quantity of the polymer support is treated with perchloric acid to release the 4,4'-dimethoxytrityl cation from the polymer support into the solution. The dimethoxytrityl cation (lambda max = 498 nm, epsilon 498 = 70,000/M) is then quantified spectrophotometrically. A comparative study of the reagent DTNPME with 2,2'-dithiobis(5-nitropyridine) is also described.

Chromatography, Affinity↗
PubMed1990

Synthetic, immunological and structural studies on repeat unit peptides of Plasmodium falciparum antigens.

Using solid phase methodology, we have synthesized five peptides (16-18 residues long) corresponding to repeat sequences of four antigens of a human malarial parasite, Plasmodium falciparum. Three of these antigens (RESA, FIRA, and ABRA) are found in the asexual blood-stages of the parasite, while the remaining one (CSP) is found in the sporozoites. The synthetic peptides, conjugated to bovine serum albumin, elicited high levels of antibodies in rabbits, and these antibodies were found to cross-react with the heterologous peptides. The degree of cross-reactivity, as estimated in an ELISA, was quite remarkable among all the peptides. The peptide corresponding to the RESA tetrapeptide repeat was found to be the most immunogenic and highly cross-reactive. For this reason this tetrapeptide repeat unit, peptide 1, may be a suitable candidate for inclusion in a multiple epitope polypeptide vaccine design. Conformational studies using circular dichroism spectroscopy show that these peptides have similar conformational characteristics with a common feature of approximately 30% and approximately 50% helical content water and TFE respectively. Theoretical predictions regarding conformation using the Chou-Fasman method have also been presented.

Amino Acid Sequence↗
PubMed1990

Use of a modified cupric acetate method for the detection and quantitation of xylanolytic activities: a comparative study with the congo red method.

A modified cupric acetate method for the screening and quantitation of xylanolytic activities was comparable with the more widely used congo red method with respect to sensitivity and ease of use and was shown to have points of merit over the latter. The use of a non-linear correction, in comparison to the conventional linear one, for the effect of dilution on the quantitative plate assay was evaluated.

Bacillus↗
PubMed1990

Scleral dellen in strabismus surgery.

This communication highlights scleral dellen as an unusual complication of strabismus surgery in a 55-year-old hypertensive male. The clinical significance, differential diagnosis and management of this condition has been discussed.

Humans↗
PubMed1990

Mechanism of protection provided by active immunization with porins in mice challenged with Salmonella typhi.

Oxygen free radical (OFR) generation capacity of peritoneal macrophages was studied by chemiluminescent technique. Chemiluminescent (CL) response of macrophages from control, infected and immunized-infected mice was observed using non specific (Latex) and specific (S. typhi, cells and porins) stimulants at different time intervals. CL response was found to be significantly higher in immunized-infected group throughout the study period using all the three stimulants as compared to that in the infected as well as uninfected control mice. The mode of action of porin vaccine in increasing capacity of generating OFR is probably through increased expression of porin (protein) as well as carbohydrate receptors on the macrophage surface which leads to the stimulation of the whole caseade of respiratory burst or through the increase in the respiratory burst enzyme activities linked with each receptor or both.

Animals↗
PubMed1990

Pattern of relapses in sporozoite induced Plasmodium cynomolgi B infection in rhesus monkeys.

The pattern of sequential relapses in 10 rhesus monkeys following inoculation of sporozoites of Plasmodium cynomolgi B has been studied after administering curative dose of chloroquine (5 mg/kg base X 7 days) to eliminate blood parasitaemia after each relapse. Observation for periods ranging from 109 to 245 days showed that the interval between first six relapses was 19.3 +/- 6.77 days (1st relapse), 20.9 +/- 8.43 days (2nd relapse), 22.8 +/- 8.55 days (3rd relapse), 27.8 +/- 10.0 days (4th relapse), 31.67 +/- 11.50 days (5th relapse) and 32.5 +/- 16.26 days (6th relapse). The results of this study indicate a gradual extension of the relapse interval in successive relapses.

Animals↗
PubMed1990

Effect of vitamin C deficiency and excess on the liver: a histopathological and biochemical study in guinea pigs fed normal or high cholesterol diet.

When guinea pigs were kept on a restricted vitamin C intake of only 0.5 mg daily, their serum ascorbic acid fell to 0.16 +/- 0.06 mg/d1 in 16 weeks as compared to 0.73 +/- 0.11 in control. This was associated with significant increase in liver cholesterol and triglycerides. When they were simultaneously challenged with a high cholesterol load, this fat accumulation was markedly exaggerated. The weight of the liver now increased by almost two-and-half times. Liver cholesterol rose to 12.90 +/- 2.63 mg/gm as compared to 3.23 +/- 0.56 mg/gm with low vitamin C alone. Histopathology showed marked distension and vacuolation of hepatocytes, focal necrosis and fibroplasia. Administration of excess vitamin C (100 mg daily) significantly countered these changes. The vitamin C-lipid relationship has important clinical bearings and liver could be an important site of vitamin C action.

Animals↗
PubMed1989

Development of a bacteria-independent model of the multiple organ failure syndrome.

Criteria that allow definition of the multiple organ failure syndrome include pulmonary, hepatic, renal, and gut barrier dysfunction along with characteristic histopathologic changes. It has been difficult to study multiple organ failure due to lack of a satisfactory experimental model that would reproduce the pathophysiologic and histopathologic characteristics, would be stable enough to allow study over several days, and would be free of exogenous primary bacterial infection. We have studied pathophysiologic and histopathologic alterations in a potential model of multiple organ failure. Wistar rats received one of the following solutions by intraperitoneal injection: 4 mL of saline, 4 mL of mineral oil, or 1 mg per gram of body weight of zymosan A in 4 mL of mineral oil. Animals that received zymosan developed hypoxia, decreased creatinine clearance, and changes in hepatic microsomal cytochrome P450 content and aniline hydroxylase activity. Bacterial translocation occurred in the zymosan group. The lungs, liver, and kidneys of the animals that received zymosan exhibited histopathologic changes. We conclude that this model fulfills our criteria for a model of multiple organ failure.

Animals↗
PubMed1989

A simple and sensitive spectrophotometric method for the quantitative determination of solid supported amino groups.

A simple and sensitive method for the quantitative determination of free amino groups on solid support is described. This approach is a modification of Ngo's [(1986) J. Biochem. Biophys. Methods 12, 349-354] method reported earlier. The method is based on the reaction of the solid support with an excess of 5'-O-(4,4'-dimethoxytrityl)-thymidine-3'-O-(2,4-dinitrophenyl) succinate (DTDS) in the presence of a catalytic amount of 4-dimethylaminopyridine. After removing the excess reagent, solid support is treated with perchloric acid to release 4,4'-dimethoxytrityl cation into the solution. The released 4,4'-dimethoxytrityl cation, which has a strong absorption at 498 nm (epsilon 498 = 70,000), is then determined spectrophotometrically. A comparative study of DTDS, N-succinimidyl-3-(2-pyridyldithio)propionate and 4,4-dimethoxytrityl chloride is also included. The method was found to be very useful to determine those amino groups which are available for functionalization of solid supports, especially, monitoring the functionalization of solid supports for affinity chromatography and synthesis of biopolymers.

Amines↗
PubMed1989

Specific immunoglobulin response in mice immunized with porins and challenged with Salmonella typhi.

Specific antiporin antibody (IgG, IgM, and IgA) response was studied in control, infected, immunized-infected, and immunized mice. The activity of specific IgG immunoglobulins was found to be the highest in immunized and immunized-infected groups in which 87.5% protection had been observed by laboratory potency test in mice; the next-highest activities were those of IgM and IgA immunoglobulins. However, in the infected group the activity of specific IgM and IgG immunoglobulins was almost similar.

Animals↗