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Biomedical subjects

D Sen

Publications and source records attributed to D Sen.

At least 145 records · Page 8Linked to original sources

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↗

Morphological, biological and antigenic properties of Neisseria gonorrhoeae adapted to growth in guinea-pig subcutaneous chambers.

Gonococci (strain BS3) passaged three times and harvested directly from plastic chambers implanted subcutaneously in guinea pigs were compared with the parent strain (BS) grown in vitro. The strain grown in vivo produced smaller colonies than that grown in vitro and when examined directly in chamber fluid was sometimes not pilated. It was more resistant to the bactericidal action of human serum and more infective for guinea-pig chambers. In gel diffusion, extracts of the organisms adapted in vivo and cultured once on agar appeared to contain one or two antigens that were different from those in extracts of the in vitro grown organisms; and on polyacrylamide gels, electrophoresis of similar extracts showed one or more protein components for strain BS3 which were not seen for strain BS. Gonococci grown in guinea-pig subcutaneous chambers appear to be suitable for studies on the determinants of gonoccal pathogenicity.

Animals↗

Occurrence and significance of Cryptosporidium infection in Calcutta.

During a 2-year study, Cryptosporidium oocysts were detected in 32 (5.6%) of 566 hospitalized paediatric diarrhoea cases and 2 (1.2%) of 167 non-diarrhoeic individuals. Cryptosporidium was the sole pathogen detected in 17 (3.0%) of the 32 positive cases; in the other 15 it occurred in combination with one or more other established enteropathogen(s). The frequency of detection of the parasite was highest in the 0-6 months age group; no sex-specific difference was discernible. The detection rate of the parasite was highest during the monsoon and post-monsoon months. Most of the patients had watery stools with a mild to moderate degree of dehydration, with the diarrhoea lasting for less than 7 d.

Age Factors↗

Acute diarrhoeal diseases in infants aged below six months in hospital in Calcutta, India: an aetiological study.

In a prospective 2-year study, 218 infants aged less than 6 months admitted to a children's hospital in Calcutta with acute diarrhoea and 102 infants (control group) from the out-patient department of the same hospital with similar age, sex and socio-economic composition as the diarrhoea patients, were concurrently investigated for enteropathogenic agents in the faeces. Enteropathogenic Escherichia coli, enterotoxigenic E. coli, and enteroadherent E. coli constituted the 3 types of diarrhoeagenic E. coli most frequently (57.4%) detected in the faeces of diarrhoeic infants either as a sole pathogen or in association with other microorganisms. Other enteropathogens detected were rotavirus, Campylobacter jejuni, Salmonella typhimurium and Aeromonas hydrophila. The frequency of detection of various aetiological agents was 72%; in the remaining 28% an infectious aetiology could not be determined. The study suggests that diarrhoeagenic E. coli plays a major role in the causation of acute diarrhoea in infants aged under 6 months in Calcutta.

Diarrhea, Infantile↗

Effect of protein rich diet during acute phase of dysentery.

Ninety six children upto the age of five years suffering from uncomplicated acute dysentery of less than 3 days' duration were studied to find out the impact of feeding of extra-protein rich diet during their acute phase of illness. These children were randomly allocated to either control group (receiving only hospital diet) and study group (receiving hospital diet and extra milk which constituted 30% of ideal total calorie requirement of patients. Patients in the two groups were comparable on admission. Forty percent reduced food intake was observed among the children of both the groups due to severe anorexia which was reflected by no significant differences in clinical outcome, anthropometrical measurements and haematological parameters between the two groups on day 7 of hospitalisation and on day 15 after discharge.

Acute Disease↗

Outbreak of dysentery due to nalidixic acid resistant S. dysenteriae 1 at Agartala, Tripura: a hospital based study.

During the epidemic of bacillary dysentery at Agartala, Tripura, a total of 62 hospitalized patients suffering from diarrhoeal diseases were studied during the later part (11-16 June, 1988) of the epidemic. Principal features of Shigellosis cases were discussed. Of these 62 cases investigated, 19(30.6%) cases had the mucoid diarrhoea. From them S.dysenteriae type 1 and S.flexneri had been recovered from 31.6% and 10.5% cases, respectively. All the strains of S.dysenteriae type 1 isolated during the period of investigation were resistant to nalidixic acid.

Disease Outbreaks↗

Multidrug resistant epidemic shigellosis in a village in west Bengal, 1984.

An out break of acute bacillary dysentery in a village called Dhamasin in Hooghly district of West Bengal was investigated during March 1984. Forty seven percent of families were affected. A total of 91 cases and 2 deaths occurred amongst 937 people giving an over all attack rate of 9.7% and a case fatality rate of 2.2 percent. Highest attack rate (22.7%) was observed in below one year age group. Multiple drug resistant Shigella dysentery type 1 strains were isolated for the first time from 6 out of 22 cases sampled at the domiciliary level. The organism was never isolated earlier during last ten years of surveillance in the infectious Diseases Hospital, Calcutta. Identification of nature of this outbreak and it's causative agent helped to realise the potentiality of extensive spread and paved the way for further investigations. Public health authorities were buffled as the rapid spread of the disease throughout the entire state of West Bengal could not be contained in spite of instituting all probable control measures on war footing.

Acute Disease↗