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Biomedical subjects

S Devi

Publications and source records attributed to S Devi.

At least 55 records · Page 3Linked to original sources
PubMed1993

Detection of antibodies against Salmonella typhi outer membrane protein (OMP) preparation in typhoid fever patients.

An indirect ELISA was used to detect antibodies against outer membrane protein preparations (OMPs) from Salmonella typhi. Sera from patients with a definitive diagnosis of typhoid fever (TF) gave a mean absorbance reading, at 414 nm, of 1.52 +/- 0.23 as compared to 0.30 +/- 0.11 for sera from healthy individuals. This gave a positive to negative ratio of absorbance readings of approximately 5.1. Suspected TF patients (no isolation of S. typhi), with positive and negative Widal titers had mean absorbance readings of 1.282 +/00.46 and 0.25 +/- 0.19, respectively. Sera from patients with leptospirosis, rickettsial typhus, dengue fever, and other infections gave mean absorbances of 0.20 +/- 0.08, 0.24 +/- 0.08, 0.27 +/- 0.08, and 0.31 +/- 0.16, respectively. The sensitivity, specificity, positive and negative predictive values were 100%, 94%, 80% and 100%, respectively. The antibody response detected in the definitive TF cases was predominantly IgG in nature and no cross-reactivity was seen with OMP preparations extracted from E. coli. Variable reactivity was noted with OMP preparations obtained from other Salmonella spp. Three major OMPs are presented in the antigen preparation and strong binding of positive sera was detected to all three bands.

Antibodies, Bacterial↗
PubMed1992

Development of fern sporangia: a fluorescence microscopy study.

The utility of fluorescence microscopy for studying development of fern spores is investigated. Changes in the fluorescence characteristics during the developmental stages of fern sporangia can be attributed to the changes in the chemical composition of the cell wall. Bright blue autofluorescence of the spores indicated the presence of sporopollenin. The sporangial walls and the spores autofluoresced yellow under blue light excitation. Fluorescence microscopy is a useful addition to light, scanning, and transmission electron microscopy because living specimens can be studied owing to their fluorescence properties.

Biopolymers↗
PubMed1992

Enzyme linked immunosorbent assay & indirect fluorescence assay for rapid diagnosis of Bacteroides fragilis infections.

Antibodies for B. fragilis (NCTC 9343) were detected in sera of 121 patients and 37 controls using four methods viz., enzyme linked immunosorbent assay (ELISA), indirect fluorescence test (JFA), countercurrent immunoelectrophoresis (CIE) and indirect haemagglutination test (IHA). Of 121 patients, 57 were culture positive for B. fragilis, 38 positive for anaerobes other than B. fragilis and 26 were negative for anaerobes. In the B. fragilis culture positive group, antibodies to B. fragilis were positive in 82.5, 84.2, 85.90 and 91.2 per cent patients by CIE, ELISA, IHA and IFA respectively. In B. fragilis positive patients IFA was more sensitive than IHA, which for other groups IHA was found to be more sensitive than IFA. When all groups were taken together IHA was found more sensitive than IFA. ELISA and IFA tests are recommended for rapid serological diagnosis of B. fragilis infections, where facilities for these tests are not available, CIE and IHA could be done. Cross reactivity with other Gram negative anaerobic and aerobic bacteria should be kept in mind since seropositivity varied for B. fragilis (82-91%). In infections with microbes other than B. fragilis seropositivity varied between 23.7 to 63.2 per cent and in patients having cultures sterile or positive for other organisms seropositivity was 30.8 to 42.3 per cent. This nonspecificity could be due to other antigens that cross react between B. fragilis and other anaerobes and aerobes or the use of an antigen lacking high purity.

Antibodies, Bacterial↗
PubMed1991

Ultrastructural and biochemical effects of cadmium on the aquatic fern Marsilea minuta Linn.

The uptake of cadmium by cultured vegetative clones of the aquatic fern Marsilea minuta was studied in a static experimental bioassay system as functions of dose and period of exposure. The pathomorphological manifestations of Cd toxicity, as studied by transmission electron microscope, indicated damage to chloroplasts and tonoplasts as well as electron opaque granular deposits. Preliminary evidence based on molecular sieving chromatography showed the formation of two cadmium-binding proteins of 78 and 33 kDa in the leaf tissue under cadmium stress.

Cadmium↗
PubMed1991

Heat-killed Salmonella typhi induces the release of prostaglandins and leukotrienes from mouse macrophages.

Mouse macrophages pre-labeled with [3H]arachidonic acid (20:4) were shown to release metabolites generated by the lipoxygenase and cyclo-oxygenase pathways following in vitro addition of heat-killed Salmonella typhi. These metabolites were maximally released after 60-90 min of incubation and consisted of prostaglandins (85%), leukotriene C (6%), di-HETEs, leukotrienes D and E (4%), mono-HETEs (2%) and other metabolites (3%). Of the metabolites generated by the cyclo-oxygenase pathway (prostaglandins), 6-keto PGF1 alpha and PGE2 were generated at a ratio of 1.2 to 1. The significance and importance of these results are discussed.

Animals↗
PubMed1991

Salmonella carriage rate amongst school children--a three year study.

As a part of three-years epidemiological survey of salmonellosis in South Kanara District, a southwest coastal region of India, an attempt was made to determine the human Salmonella carriage rate during the period between 1981 to 1983. One thousand and two asymptomatic school children 5 to 15 years of age, 42 restaurant employees and 17 dairy workers formed the subjects of this bacteriological study. The Salmonella carriage rate among healthy school children from a single fecal sampling was 1% and no Salmonellae were recovered from the feces of restaurant and dairy workers. Ten school children excreted Salmonellae which belonged to 6 different serotypes-Salmonella oslo, S. ohio, S. typhimurium, S. urbana, S. cerro and S. derby; S. oslo and S. ohio were the most frequent serotypes. No-S. typhi, S. paratyphi A or S. paratyphi B were recovered. All Salmonella strains recovered during this study were dual or multiple drug resistant, sulfadiazine and tetracycline resistance being commonly observed. The significance of excretion of potentially pathogenic, drug resistant Salmonellae by symptomless school children is discussed from public health point of view.

Adolescent↗
PubMed1990

Chlorotetracycline induced fluorescence of antherozoids in ferns.

A quick method based on chlorotetracycline induced fluorescence of the antherozoids is described. This method was found suitable for studying the number and duration of motility of antherozoids in toxicity studies where male fertility is a significant character.

Chlortetracycline↗
PubMed1989

Haplotypes in tribal Indians bearing the sickle gene: evidence for the unicentric origin of the beta S mutation and the unicentric origin of the tribal populations of India.

To determine the origin of sickle cell anemia (SS) in India, we analyzed haplotypes of the beta gene cluster in beta S-carrying individuals belonging to tribal populations living in the Nilgiris region of southern India and complemented the available data on tribes of east-central India. We found that in the Nilgiris tribes chromosomes bearing the beta S gene are linked in 91% of the cases to the "Asian" (Arab-Indian) haplotype (although 25% of the haplotypes had the epsilon polymorphic site negative, making the 5' portion of the haplotype identical with the African Senegal haplotype). These XmnI (+) chromosomes were associated with high G gamma expression (67.2 +/- 5.9%) and a high percentage of Hb F (15.5 +/- 7.9%; range, 6-25.3%). We have similar findings for tribal groups from west-central India (Gujarat). In east-central India we have confirmed the data of others, finding the same haplotype linked to beta S in tribes living in the east (Orissa, Andhra Pradesh). We conclude that the beta S gene in presently isolated and disperse tribal populations in India is associated with one predominant typical haplotype, suggesting a unicentric origin of the mutation in India. In addition, this finding implies a unicentric origin of the tribal populations themselves: The gene must have arisen and spread before tribal dispersion. Furthermore, we find extremely high frequencies of the (-alpha) haplotype in the Nilgiris (0.89) and in Gujarat (0.95). The beta S gene linkage to a high Hb F-expressing haplotype and the high incidence of alpha-thalassemia predict a mild phenotypical expression of sickle cell anemia in India.

Anemia, Sickle Cell↗
PubMed1988

Functional and ultrastructural changes of platelets in malarial infection.

This paper describes changes in the circulating platelets of 25 patients with acute malaria within 2 to 6 days of onset of illness. Thrombocytopenia was observed in 10 out of 15 patients with Plasmodium falciparum infection, and in 4 out of 9 patients with P. vivax infection. One patient with a mixed infection of both species had a disseminated intravascular coagulation. Platelet antibody was detected in the sera of 8 out of 11 cases by the complement lysis inhibition technique and indirect immunofluorescence. The mean platelet antibody concentrations in the sera of 11 patients and 53 control subjects were 122.70 +/- 80.25 ng/10(7) platelets and 36.69 +/- 18.72 ng/10(7) platelets, respectively. An inverse relationship between the platelet count and platelet antibody levels in serum supported the view that thrombocytopenia in malaria may be partly immune-mediated. Platelet aggregation responses to agonists such as ADP, adrenaline, collagen and ristocetin revealed hyperactivity. Ultrastructural study of unstimulated platelets from patients revealed several changes such as centralization of dense granules, glycogen depletion, and formation of pseudopods and microaggregates, indicating in vivo activation of the platelets, which may also lead to thrombocytopenia.

Adolescent↗
PubMed1988

Phycotoxicity of linear alkylbenzene sulfonate.

Dose- and time-dependent effects of linear alkylbenzene sulfonate, a major component of synthetic detergent, to the blue-green alga Nostoc muscorum, were studied under laboratory conditions. Toxicity was evident, at doses above 0.001%, from the decrease in biomass, heterocyst number, and protein content and pathomorphological alterations.

Alkanesulfonates↗
PubMed1988

T cell-mediated cytotoxicity against dengue-infected target cells.

A cytotoxic T lymphocyte (CTL) response to dengue virus-infected target cells is described. Effector cells were generated in an in vitro secondary culture and appeared to be T cells possessing both the Lyt 1.1 and Lyt 2.1 surface antigens. A stronger CTL response was noted with the H-2k haplotype compared to H-2d, and H-2 compatibility was required between CTL and target cells. CTL generated showed some cross-reactivity with target cells infected with Japanese encephalitis virus (JEV), another flavivirus, but not with target cells infected with an alphavirus, Sindbis. The significance and importance of these findings are discussed.

Animals↗