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D Sen

Publications and source records attributed to D Sen.

At least 127 records · Page 7Linked to original sources

Kanagawa phenomenon and serotypic pattern of Vibrio parahaemolyticus strains isolated from various sources in Calcutta.

A total of 135 strains of Vibrio parahaemolyticus isolated during the period 1976-77 from human gastroenteritis cases and various categories of environmental sources, e.g., crustaceans, fish and different water samples (pond, stored, open well and tap water) were tested for their Kanagawa phenomenon and serotypic pattern. Amongst the 80 human isolates tested, 69 strains (86.3%) were Kanagawa phenomenon positive, and 60 strains (75.0%) were serologically typable--the dominant serotype being 05:K15. Of the 25 isolates from various water sources 10(40.0%) were Kanagawa phenomenon positive, and 17(68.0%) were serologically typable and 4 (23.5%) of them belonged to serotype 05:K15. All the 30 strains isolated from crustaceans and fish were Kanagawa phenomenon negative and 22 (73.3%) of them were serologically typable, belonging to heterogeneous serotypes. The results of this study also indicate the possible role of water in the transmission of V. parahaemolyticus infection in Calcutta slums.

Food Microbiology↗

An epidemic of rotavirus diarrhoea in Manipur, India.

Recurrent epidemics of acute diarrhoeal disease in young children have occurred during the winter months in Manipur (India) for many years. During November 1979, children admitted to hospital for acute diarrhoea were investigated and, in addition to pathogenic Escherichia coli and Shigella rotovirus was detected by ELISA in a number of stool samples, especially of those less than one year old. The importance of this finding and the need for further study are discussed.

Diarrhea, Infantile↗

A controlled field trial of an aluminum phosphate-adsorbed cholera vaccine in Calcutta.

A controlled field trial to determine the efficacy of a single dose of an aluminium phosphate-adsorbed cholera vaccine was conducted in Calcutta during 1975-77. An aluminium phosphate-adsorbed tetanus toxoid was used as the placebo. Follow-up of the immunized volunteers for a period of two years showed that the adsorbed cholera vaccine provided 100% protection to children under five years of age for 6 months, 88.9% for 12 months, and 91.7% for 18 months (P<0.05). The overall protection for all age groups was 58.5% for 18 months. There were no serious side effects following the anti-cholera inoculations.

Adjuvants, Immunologic↗

Effect of doxycycline on transmission of Vibrio cholerae infection among family contacts of cholera patients in Calcutta.

Doxycycline was used among the family contacts of hospitalized cholera patients in Calcutta to determine its effectiveness in controlling transmission of V. cholerae infection. A total of 137 such contacts were given a single oral dose of doxycycline in graded doses according to age. A similar group of 139 contacts received a single dose of multivitamins as placebo. All 276 contacts were examined bacteriologically daily for 10 days for the presence of V. cholerae in their stools. The results showed that doxycycline was effective in significantly reducing the load of V. cholerae infection for up to 5 days following treatment.

Adolescent↗

Immunization of guinea pigs with Neisseria gonorrhoeae: strain specificity and mechanisms of immunity.

Infection of subcutaneusly implanted chambers in guinea pigs conferred immunity against homologous infection of other chambers in the same animals. However, attempts to immunize guinea pigs by subcutaneous injection of filtered fluid from infected chambers, or with small doses of formalin-killed, chamber gonococci were not successful. Thus, neither organisms grown in vivo nor their extracellular products appeared to be exceptionally immunogenic. In immunizing tests with different isolates of gonococci adapted to growth in guinea-pig chambers, cross-immunity to chamber infection with low challenge doses was detected only between two of six isolates. The killing of gonococci in chambers of immunized animals, which occurred only after homologous challenge or with the heterologous strain showing cross-immunity, was not due primarily to humoral factors in the chamber fluid but probably to an enhanced effectiveness of phagocytosis. The serum of immunized animals was bactericidal for homologous strains and for the strain showing cross-immunity but not for strains showing no cross-immunity. Hence, serum bactericidal activity might be a useful indicator for investigating the specificity of immunity produced by different gonococcal strains.

Animals↗

Resistance of Neisseria gonorrhoeae grown in vivo to ingestion and digestion by phagocytes of human blood.

Attempts to study quantitatively the phagocytosis of gonococci from urethral pus failed because of the small numbers of organisms and technical difficulties. However, gonococci from chambers implanted subcutaneously in guinea pigs, which were similar to gonococci from urethral pus in their resistance to killing by human serum, were obtained in sufficient quantities for comparison in phagocytosis tests with the in vitro grown strains from which they were derived. Microscopic and viable counts of gonococci in phagocytes showed that in vivo grown organisms (strain BSV) were readily phagocytosed by human polymorphonuclear phagocytes. There was little difference betweee to ingestion. There was, however, a marked difference in the intracellular survival of strains BSV and BS during the first hour of phagocytosis. Whereas BSV organisms survived well, many BS organisms were killed. Subsequently, strain BSV and the survivors of the strain BS inoculum responded similarly to the intracellular bactericidins. These results were supported by electron microscopy of infected phagocytes. Resistance of gonococci in vivo to ingestion and digestion by human phagocytes seem to be important facets of the pathogenesis of gonorrhoea.

Humans↗