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Biomedical subjects

P Datta

Publications and source records attributed to P Datta.

At least 91 records · Page 5Linked to original sources
PubMed1986

Rectal histology in acute bacillary dysentery.

A recent epidemic of acute Shigella dysentery in West Bengal (India) provided us with an opportunity to examine the rectal mucosal abnormalities seen in this condition. One hundred two patients were investigated using sigmoidoscopy, rectal biopsy, and rectal swab for culture. Pure culture of Shigella was obtained in 37 cases, and the rectal biopsy specimens from these patients were assessed in detail. The mean (+/- SD) duration of illness was 47.8 +/- 27.4 h (range 8-120 h), and most patients (31 of 37, 84%) had diarrhea with blood and mucus in the stools. Significant findings at histology were as follows. (a) Cellular infiltrate was predominantly round cell or mixed round cell and neutrophilic in the majority of patients (27, 73%). (b) Disorganization of crypts was seen in as many as 31 patients (84%); in most subjects the distorted architecture was mild, but in a few the defect was severe with crypt branching and dilatation. (c) In the majority of patients the inflammatory process extended to the muscularis mucosae and submucosa; edema with or without increased cellular infiltrate was seen in the muscularis mucosae in 92% and in the submucosa in 80%. (d) There was no difference in the rectal histology of patients with a short history of disease (less than 48 h) compared with those with a longer history, except for goblet cell depletion which was more in those with diarrhea for more than 48 h. (e) The mucosal abnormalities in patients with watery diarrhea were, in general, milder than in those with dysentery, although the difference was statistically not significant; 2 of 6 patients with watery diarrhea had severe colitis. (f) The mucosal abnormalities were more severe in patients with Shigella dysenteriae infection compared with Shigella flexneri.

Adolescent↗
PubMed1986

Interference by IgG paraproteins in the Jaffe method for creatinine determination.

A large (60-100%) negative interference in serum creatinine value of some (3 of 18 myeloma patients, all with monoclonal gammopathy of IgG type, was observed on several instruments that determine creatinine by the Jaffe reaction. No interference was observed in an enzymatic method. Serum electrophoresis showed a monoclonal band in all three samples. The interferent could be removed by acid precipitation or dithiothreitol preincubation, and partially isolated in the high molecular weight dialyzate from the serum. It was demonstrated that the interferent is not albumin or normal gammaglobulin. Kinetic analysis of the Jaffe reaction showed large initial decreases in absorbance, in agreement with the corresponding creatinine results. It is suggested that some monoclonal IgGs may react with the Jaffe picrate reagent, resulting in a false lowering of serum creatinine values.

Blood Protein Electrophoresis↗
PubMed1986

Quality control for a 14- to 18-megohm-cm deionized water supply.

We studied the quality control for a 14- to 18-megohm-cm deionized water system with multiple outlets. The quality of water was determined by measuring specific resistance, performing a total colony count, trace metal analysis, and high-performance liquid chromatographic analysis. The specific resistivity of water was at the level of 17 to 18 megohms-cm at the recirculation loop and greater than 10 megohms-cm at the individual faucets. The microbial content was consistently less than 100 colony-forming units/mL. Periodic trace-metal analysis indicated less than 1 microgram/L of copper, bismuth, zinc, cadmium, mercury, thallium, and lead. High-performance liquid chromatographic analysis, as determined by the absorbance of the highest peak by ultraviolet and fluorescence spectroscopy, indicated less than or equal to 0.001 absorbance unit. Our experience suggests that maintaining laboratory water at 14 to 18 megohms using a plastic system with plastic faucets eliminates the likelihood of bacterial organic and trace-metal contamination of the water.

Chromatography, High Pressure Liquid↗
PubMed1985

Molecular cloning and expression of the biodegradative threonine dehydratase gene (tdc) of Escherichia coli K12.

The biodegradative threonine dehydratase gene (tdc) of Escherichia coli was cloned by isolating a dehydratase negative mutant after Tn5 mutagenesis, cloning the tdc::Tn5 DNA into pBR322 and then replacing the Tn5 element on the plasmid in vivo. Subcloning and nucleotide sequence data revealed two distinct procaryotic promoter-like elements each containing a potential CAP-binding site and AT-rich regions, and a Shine-Dalgarno sequence. One of these putative promoters, P2, was located immediately upstream from the tdc coding region, and a second, P1, was approximately 1 kilobase upstream from P2. Deletion of the potential CAP-binding site from P1 prevented tdc gene expression. However, removal of P2 and a large segment of the upstream DNA had no discernible effect on dehydratase synthesis. A 936-base pair open reading frame was found between P1 and the tdc coding region, which produced a polypeptide of about 32 kilodaltons. The data suggest that P1, and not P2, is necessary for tdc gene expression, and that the DNA sequences coding for the 32 KD polypeptide and threonine dehydratase are part of a single transcriptional unit.

Amino Acid Sequence↗
PubMed1984

Role of rotavirus as the cause of acute paediatric diarrhoea in Calcutta.

Of the 245 acute paediatric diarrhoea cases admitted to the Infectious Diseases Hospital, Calcutta between July, 1979 and June, 1981, rotavirus was detected in the faeces of 55 (22.4%) patients either as the sole aetiological agent or in association with other enteropathogens. Children aged six months to two years were most commonly infected. The virus was detected throughout the year with higher incidence during the winter months of both years. The frequency of detection of major enteropathogens other than rotavirus was Vibrio cholerae biotype El Tor (31.0%), enteropathogenic Escherichia coli (8.2%) and enterotoxigenic E. coli (6.5%).

Child↗
PubMed1984

Studies on Escherichia coli as a cause of acute diarrhoea in Calcutta.

The prevalence of different types of diarrhoea-producing Escherichia coli among 240 patients with acute diarrhoea in hospital was investigated. The 25 patients (10.4% of the total) from whose faeces we isolated enteropathogenic E. coli (EPEC) were all less than 5 years old but the 29 (12.1%) from whom we isolated enterotoxigenic E. coli (ETEC) were of various ages, most of them greater than 12 years old. No enteroinvasive E. coli (EIEC) strains were isolated. ETEC strains that produced heat-labile toxin (LT) were encountered more often than those that produced either heat-stable toxin (ST) alone or both LT and ST. The ETEC isolates were distributed among eight different serotypes, the commonest being O148:H28 (38%). Correlations between enterotoxin production, serotype pattern and possession of colonisation factor antigens I and II were observed.

Acute Disease↗
PubMed1984

Escherichia coli K-12 mutation that inactivates biodegradative threonine dehydratase by transposon Tn5 insertion.

From a collection of kanamycin-resistant mutants of Escherichia coli K-12 isolated by transposon Tn5 mutagenesis, we have identified a mutant that lacks functional biodegradative threonine dehydratase (EC 4.2.1.16) by direct enzyme assay and by the loss of cross-reacting material with affinity-purified antibodies against the purified enzyme. Aerobic and anaerobic growth of this strain on various carbon sources failed to reveal a phenotype. Evidence for the insertional inactivation of threonine dehydratase by Tn5 was obtained by cloning the DNA segments flanking the Tn5 insertion site into pBR322 and hybridizing the cloned DNA to a synthetic oligodeoxynucleotide probe complementary to the DNA segment coding for a unique hexapeptide at the amino terminus end of the enzyme; the region of homology to the synthetic cDNA sequence appears to be located within about 500 nucleotides from one end of Tn5. Genetic analysis with the transposon element that caused insertional inactivation located the tdc gene at min 67 on the E. coli chromosome.

Base Composition↗