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Biomedical subjects

D Sen

Publications and source records attributed to D Sen.

At least 91 records · Page 5Linked to original sources
PubMed1991

Epidemiology of campylobacteriosis in a cohort of rural population near Calcutta.

Over a 2-year period, 25 families comprising of 181 individuals of all ages were longitudinally observed for the excretion of Campylobacter species. Faecal samples were taken from all persons with diarrhoea. Specimens were also taken from apparently healthy individuals and from domestic animals living within the confines of the study families at monthly intervals. The overall diarrhoea attack rate was 19 episodes per 100 person-years with peak incidence in the 1- to 4-year-old age group (76/100 person-years). Eight (11.5%) of the total episodes were campylobacter-associated and the overall rate of campylobacter positive diarrhoeal episodes were 2.2 per 100 person-years. Of the 1002 stool samples from healthy individuals 32 (3.2/100 samples) were positive for campylobacter. The organism was most frequently isolated from children under 1 year of age both during diarrhoeal episodes (11.5 per 100 person-years) and non-diarrhoeal (11.1 per 100 samples). Multiple infections in a family were rare. In 19.4% of the occasions one or more animals were campylobacter positive. However, only in 7.7% of these occasions was a human infection recorded within 1 month after the animal was found to be positive. The study showed that the epidemiology of campylobacteriosis in this community was distinct compared to that observed in developed countries.

Adolescent↗
PubMed1991

Serovars of multi-antibiotic resistant Escherichia coli from the freshwater environs of Calcutta, India.

For a period of one year (March 1987 to February 1988), the incidence of Escherichia coli was determined in water, sediment and plankton collected from two sampling sites in a freshwater lake extensively used by humans and animals. Densities of E. coli associated with plankton was the lowest while sediments, especially at site 2, harbored high densities of the organism. Correlation coefficients revealed that the density of E. coli in water samples was linearly correlated to temperature, pH of water, sediment and humidity. Stepwise multiple regression analysis, however, showed that sediment temperature was the dominant variable which could explain 27% of the observed variation in the numbers of E. coli in the overlying waters (p = less than 0.001). Of the 150 environmental E. coli strains which were characterized, 31 (20.7%) were found to belong to the classic enteropathogenic E. coli (EPEC) serogroups. Seven of the serogroups among the environmental EPEC strains were also encountered from EPEC strains isolated from human cases during a concurrent clinical study. None of the 150 environmental strains were enterotoxigenic or enteroinvasive but 4 strains possessed HEp-2 cell adhesive factor. With the exception of one, all the EPEC strains isolated were multi-drug resistant. From this study, it was evident that the lake is an important source of infection of EPEC and other related diarrheagenic E. coli.

Diarrhea, Infantile↗
PubMed1991

Prospective hospital based study on persistent diarrhoea.

A total of 383 children aged less than 5 years suffering from acute watery diarrhoea or dysentery were studied in hospital to determine the rate of persistent diarrhoea. Altogether 335 (87.5%) recovered within 13 days. Only in 48 (12.5%) did the diarrhoea continue for 14 days or more, and they were considered as having persistent diarrhoea. Children aged between 7 and 18 months had a significantly increased incidence of persistent diarrhoea. Children suffering from grade II-IV malnutrition constituted the majority (70.8%) of those with persistent diarrhoea. Higher rates of isolation of Shigella flexneri, Shigella dysenteriae 1, and Salmonella typhimurium were observed among patients with persistent diarrhoea than in those with diarrhoea of shorter duration. No positive correlations were observed between the clinical severity of disease at hospital admission and measles. Breast fed babies were not prone to persistent diarrhoea.

Acute Disease↗
PubMed1991

Randomized clinical trial of norfloxacin for shigellosis.

In a randomized clinical trial, norfloxacin was compared with nalidixic acid in the treatment of acute invasive diarrhea, with particular reference to shigellosis in adults. Of 104 patients studied, 40 were positive for Shigella in stool cultures, of which 22 received norfloxacin and 18 received nalidixic acid. The patients in these two groups were comparable on admission. In the treatment of culture-positive shigellosis cases, the responses to therapy with both drugs were similar, except that the duration of fever, anorexia, and abdominal pain were less in those who received norfloxacin. Norfloxacin appeared to be superior to nalidixic acid in the treatment of shigellosis cases caused by Shigella strains resistant to nalidixic acid.

Adult↗
PubMed1991

Prevalence of Clostridium difficile in hospitalised patients with acute diarrhoea in Calcutta.

During a 12-month period, Clostridium difficile was isolated from 38 (11.1%) of 341 hospitalised patients suffering from acute diarrhoea and from five (3%) of 172 patients as control who were admitted with illnesses other than diarrhoea. It was the sole bacterial pathogen in 31 cases. 87% of the isolates obtained from patients with diarrhoea produced neutralisable cytotoxin. None of these patients had any history of previous treatment using antibiotics. No age or gender-specific high incidence was observed. Clinical presentation in these patients revealed no distinctive pattern. Both dysenteric and diarrhoeal presentations were found, the latter being more frequent. The results suggest that Clostridium difficile by itself may be a causal agent of acute diarrhoea.

Acute Disease↗
PubMed1991

Oral rehydration solution containing 90 millimol sodium is safe and useful in treating diarrhoea in severely malnourished children.

The safety and efficacy of standard oral glucose-electrolyte solution, containing 90 mmol of sodium per litre, was evaluated in the treatment of dehydrating diarrhoea among severely malnourished (marasmic) children. A total of 81 male children aged between 6 and 48 months were studied; 41 were in the malnourished group (study group: less than 60% of Harvard Standard weight-for-age) and 40 were in the well-nourished group (control group: 80% or more Harvard Standard weight-for-age). Children of both groups could be rehydrated with standard oral rehydration solution (ORS) without encountering any clinical or biochemical complications. The results of this study lend support to the World Health Organization's concept of a unified formula of ORS for the treatment of all cases of acute diarrhoea, including severely malnourished children.

Child, Preschool↗
PubMed1991

Blood group and shigellosis.

A study on the distribution of ABO blood groups was carried out on 85 patients with clinically and bacteriologically proven shigellosis. A significant association (P less than 0.01) of blood group B was observed with shigellosis cases in comparison to controls from whom no Shigella species or other enteropathogen could be isolated. Patients with isoagglutinin B or those who possess blood group B antigen may be at a relatively increased risk of shigellosis.

ABO Blood-Group System↗
PubMed1991

Murine memory B cells are multi-isotype expressors.

Flow cytometric analyses of the surface immunoglobulins of murine memory B cells revealed the existence of populations expressing multiple isotypes, including an IgM+/IgG+ population that could be stimulated in vitro with antigen to secrete both IgM and IgG. Female BALB/c mice were immunized with R-phycoerythrin (RPE), a fluorescent photosynthetic accessory protein from red algae. Pooled splenocytes from these mice at different stages of immunization were stained with RPE as well as with allophycocyanin- and fluorescein-conjugated anti-isotype antibodies and analysed on a two-laser FACS. RPE-binding cell sub-populations were defined and selectively sorted to verify their phenotype and to demonstrate that the various subpopulations (IgM+/IgG+, IgM+/IgG-, IgM-/IgG+) had different isotype-secretion patterns when challenged with RPE in vitro. These results re-affirm the notion that a transcriptional processing mechanism may be responsible for the simultaneous expression of multiple isotypes in memory cells.

Animals↗
PubMed1990

A sodium-potassium switch in the formation of four-stranded G4-DNA.

Single-stranded complex guanine-rich DNA sequences from chromosomal telomeres and elsewhere can associate to form stable parallel four-stranded structures termed G4-DNA by a process that is anomalously dependent on the particular alkali metal cation that is present. The anomaly, which is not found in the formation of G4-DNA by oligonucleotides containing short, single runs of three or more guanines, is caused by potassium cations excessively stabilizing fold-back intermediate structures, or pathway by-products.

Animals↗