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Biomedical subjects

S K Nath

Publications and source records attributed to S K Nath.

46 records · Page 3Linked to original sources
PubMed1989

Cereal based oral rehydration solutions.

A total of 257 boys (age range 4-55 months), who had acute diarrhoea with moderate to severe dehydration, were randomly assigned to treatment with either the World Health Organisation/United Nations Childrens Fund (WHO/Unicef) recommended oral rehydration solution or cereal based oral rehydration solution made either of maize, millet, sorghum, or rice. After the initial rehydration was achieved patients were offered traditional weaning foods. Treatment with oral rehydration solution continued until diarrhoea stopped. Accurate intake and output was maintained throughout the study period. Efficacy of the treatment was compared between the different treatment groups in terms of intake of the solution, stool output, duration of diarrhoea after admission, and weight gain after 24, 48, and 72 hours, and after resolution of diarrhoea. Results suggest that all the cereal based solutions were as effective as glucose based standard oral rehydration solution in the treatment of diarrhoea.

Dehydration↗
PubMed1989

Invasion of HeLa cells by beta-hemolytic group G streptococci.

The invasion of HeLa cells by beta-hemolytic Lancefield group G streptococci was studied by measuring the number of bacterial cells that survive exposure to gentamicin. Approximately 50% of bacteria introduced to the HeLa cell monolayer survived gentamicin treatment, suggesting that they were intracellular. Electron microscopy of these preparations showed intracellular bacteria in the cytoplasm, not surrounded by host cell membranes. Trypsinized bacteria incubated with HeLa cells were all killed by gentamicin. It appears that the beta-hemolytic group G streptococci have mechanisms for entry into human epithelial cells which may have importance in the virulence of the organisms.

Cytoplasm↗
PubMed1989

Emergence of Na+-glucose cotransport in an epithelial secretory cell line sensitive to cholera toxin.

Epithelial properties and effects of cholera toxin (CT) and glucose were investigated in human rectal tumor cell line HRT-18. Addition of 10(-3) M dibutyryl adenosine 3',5'-cyclic monophosphate (DbcAMP), 10(-8) M vasoactive intestinal peptide, 10(-5) M epinephrine, and 10(-5) M forskolin to the serosal side and of 3.5 micrograms/ml CT to the mucosal side and of 2 micrograms/ml A23187 to both the serosal and mucosal sides raised short-circuit current (Isc). This rise was reversed by serosal addition of 5 x 10(-5) M bumetanide or 10(-4) M ouabain. In filters treated with CT, Isc and net chloride flux (JClnet) increased after 60 min from 0.05 +/- 0.008 and -0.04 in the Ringer to 0.32 +/- 0.05 and -0.33 mueq.h-1.cm-2, respectively. Addition of 10(-2) M glucose further raised Isc by stimulating net sodium flux (JNanet) (0.70 +/- 0.08 and + 0.58 mueq.h-1.cm-2, respectively). This additional augmentation of Isc was reversed by 0.5 mM phlorizin and was mimicked by 3-O-methyl-D-glucose. When the filters were stimulated by cAMP for 15 min, Isc was also enhanced by addition of glucose. In untreated filters, Isc, JNanet, and JClnet did not differ significantly before and after addition of glucose. It is concluded that HRT-18 cells in basal state do not display absorptive properties but secretory properties stimulated by CT. However they exhibit Na+-glucose cotransport once stimulated by either CT or cAMP.

Adenocarcinoma↗
PubMed1989

[Glucose stimulates the absorption of sorbitol through the human jejunal mucosa].

Digestive tolerance of sorbitol in man varies according to whether it is taken in an empty stomach or during the meal. This suggests a regulatory step in the absorption of sorbitol in the small intestine. The mechanism of intestinal transport of sorbitol was studied in vitro in jejunal fragments obtained by endoscopy or by surgery. The intracellular concentration (C) of sorbitol was measured at stationary state in the presence of 10 mmol sorbitol in the incubation medium (M). The ratio C/M was less than 1 (0.66 +/- 0.04, mean +/- SEM) and was not modified by phloridzin (0.63 +/- 0.06) or metabolic inhibitors (0.59 +/- 0.03) but was diminished by ouabain (0.5 +/- 0.05, p less than 0.05). The influx of sorbitol across the luminal membrane increased linearly with increasing concentration of sorbitol in the medium and was more pronounced in the presence of glucose (p less than 0.01). Unlike glucose, addition of sorbitol to the mucosal side did not enhance the absorption of sodium as monitored by the increase in short circuit current in Ussing chambers. A net absorption of sorbitol stimulated by glucose was observed. The absorption of sorbitol can be explained by a simple diffusional component dependent on the concentration gradient of sorbitol and by another yet unidentified mechanism stimulated by glucose.

Biological Transport↗
PubMed1988

Randomized treatment of patients with typhoid fever by using ceftriaxone or chloramphenicol.

Sixty-three patients with Salmonella typhi infections were randomly assigned to receive either ceftriaxone iv in single daily doses of 75 mg/kg for children and 3-4 g for adults for seven days or to receive 60 mg of chloramphenicol/kg a day orally or iv in four divided doses until defervescence and then 40 mg/kg a day to complete 14 d. In the ceftriaxone group, one death occurred, and two of seven patients still febrile 11 d after starting treatment were given chloramphenicol. In the chloramphenicol group, one death and one gastrointestinal perforation occurred. The probability of remaining febrile was similar for both groups during the first seven days but was significantly greater for patients receiving ceftriaxone during the 14-d period. Patients in the chloramphenicol group were more likely to be bacteremic on day 3. These results suggest that a seven-day course of once-daily ceftriaxone shows promise as an alternative to 14 d of chloramphenicol for treating typhoid fever.

Adolescent↗
PubMed1988

Attenuation of transcription of biotin genes in Escherichia coli.

The nature of RNA synthesis from the divergent bioA:BFCD operon has been studied in vivo in Escherichia coli minicells. Minicells containing bio-recombinant plasmids produce 96 nucleotide long RNA. This small RNA was characterized by blotting on diazobenzyloxymethyl cellulose paper and hybridization with the appropriate bio-probe DNA. Determination of beta-galactosidase, using biotin requiring mutant cells of E. coli JM101 infected with a bio-M13 recombinant phage containing the functional bioB region of the operon, demonstrated the presence of a transcription termination site in the bioBFCD segment. There was a three- to five-fold reduction in beta-galactosidase activity in this system at an appropriate d-biotin concentration which indicated that the early termination of transcription is biotin dependent. From the nucleotide sequence of the promoter proximal region of the bioB gene, a 13-oligonucleotide sequence believed to be the early transcription termination site has been located. A model of regulation at termination has been proposed on the basis of the not-too-stable RNA secondary structure at the site of early termination of transcription.

Amino Acid Sequence↗
PubMed1985

Shigella septicemia: prevalence, presentation, risk factors, and outcome.

The prevalence, presentation, and outcome of bacteremia due to Shigella and other gram-negative bacteria were determined by review of records of 2,018 inpatients with shigellosis who had their blood cultured in a Bangladeshi hospital in 1976-1983. Shigella bacteremia occurred in 82 (4.1%) patients; other bacteremia occurred in 102 (5.1%) patients. Patients with shigella sepsis more frequently (P less than .02) manifested severe dehydration, abdominal tenderness or ileus, agitation or lethargy, and leukocytosis than did nonbacteremic controls; they developed more frequently (P less than .05) renal failure (26%), leukemoid reaction (22%), thrombocytopenia (20%), and hemolytic-uremic syndrome (6%). The prevalence of all bacteremia was highest in the first year of life. Protein-energy malnutrition was a strong risk factor for shigella sepsis (P less than .01). The fatality rate in shigella bacteremia (21%) was higher (P less than .005) than in nonbacteremic shigellosis (10%) but lower (P less than .001) than in other bacteremia (51%). At highest risk of death from shigella bacteremia (P less than .01) were patients less than one year old, non-breast-fed, malnourished, and afebrile.

Adolescent↗
PubMed1982

Abortive termination of bioBFCD RNA synthesized in vitro from the bioABFCD operon of Escherichia coli K-12.

The nature of divergent transcription from the bioABFCD gene cluster of Escherichia coli K-12 has been studied in vitro by using DNA restriction fragments as templates. The in vitro RNA transcript initiated at the promoter pa was found to be similar to the in vivo bioA transcript, whereas the transcription initiated at pB produced a small piece of RNA less than 200 nucleotides long. Substituting ITP for GTP or using an S100 cell-free extract as a source of antiterminator permitted transcription of the bioBFCD gene cluster initiating at the promoter pB to be read through. The possible site for in vitro transcription termination in the bioB region is discussed.

Biotin↗
PubMedDate not supplied

Typhoid fever complicated by intestinal perforation: a persisting fatal disease requiring surgical management.

In Bangladesh, clinical records of 323 patients with typhoid fever were reviewed to study the incidence, fatality, and optimal therapy of the complication of intestinal perforation. Fifteen patients (4.6%) developed intestinal perforation. Case-fatality rates were six of nine patients treated medically and one of four patients treated surgically for whom the postoperative courses were known. A literature review of 57,864 cases of typhoid fever in developing countries in the antibiotic era revealed that perforation developed in 2.5% of patients, a percentage that was similar to the incidence of 2.8% reported in the preantibiotic era. The median of case-fatality rates in these reports was 43% and the proportion of all reported typhoid deaths attributable to perforation was 25%. The case-fatality rates for patients with perforation were 70% for 410 patients managed medically and 26% for 1,835 patients managed surgically. Although some reports were biased toward placing patients at lower risk into surgical treatment, the large number of patients treated successfully by surgery suggests real improvement in surgical techniques in countries with endemic typhoid fever. These results indicate that intestinal perforation persists as a major cause of death in cases of typhoid fever in developing countries in the antibiotic era and that surgical treatment with use of antibiotic therapy is optimal for this complication.

Adolescent↗