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Biomedical subjects

A Pal

Publications and source records attributed to A Pal.

At least 91 records · Page 5Linked to original sources
PubMed1992

Reassessment of the prevalence of heat-stable enterotoxin (NAG-ST) among environmental Vibrio cholerae non-O1 strains isolated from Calcutta, India, by using a NAG-ST DNA probe.

A collection of 521 environmental isolates of Vibrio cholerae which were previously examined by the suckling mouse assay and found to be negative for the heat-stable enterotoxin NAG-ST were reassessed by a recently developed DNA probe for NAG-ST. A total of 12 (2.3%) of the isolates hybridized with the NAG-ST probe. By using a cholera toxin (CT) DNA probe, the CT gene was detected in six of the strains in the collection, although none of the isolates of V. cholerae non-O1 hybridized with both of the toxin probes. All of the NAG-ST and CT probe-positive strains were hemolysin positive. Thirty-fold-concentrated supernatants of the three representative NAG-ST DNA probe-positive V. cholerae non-O1 strains gave positive fluid accumulation ratios in the suckling mouse assay even after heating (100 degrees C for 5 min) and also inhibited the binding of a NAG-ST monoclonal antibody to the bound NAG-ST in a competitive enzyme-linked immunosorbent assay (ELISA). Likewise, all six CT probe-positive V. cholerae non-O1 strains produced in vitro CT when examined by the CT bead ELISA. HindIII digest patterns of chromosomal DNA from the representative NAG-ST gene-positive strains were visually indistinguishable. Between the groups of NAG-ST probe-positive strains examined, there was a variation in the hybridizable fragments, with one group of strains exhibiting a hybridizable fragment similar to that of the NRT 36 reference strain; a smaller HindIII fragment hybridized with the NAG-ST probe in the other group of strains.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Taxonomical implications of the emergence of high frequency of occurrence of 2,4-diamino-6,7-diisopropylpteridine-resistant strains of Vibrio cholerae from clinical cases of cholera in Calcutta, India.

Of the 110 consecutive isolates of Vibrio cholerae recovered from cholera patients admitted to the Infectious Diseases Hospital, Calcutta, India, between July 1989 and October 1990, 90 and 82.7% were resistant to 10 and 150 micrograms of 2,4-diamino-6,7-diisopropylpteridine (O/129), respectively. Additionally, all O/129-resistant strains of V. cholerae were multiply resistant to antimicrobial agents. Except in the cases of four strains, resistance to O/129 was invariably linked with resistance to co-trimoxazole. Although O/129 susceptibility is still a useful test for Vibrio identification, resistance of V. cholerae to this compound in local areas might occasionally pose a problem.

Cholera↗
PubMed1992

Acute secretory travellers' diarrhoea caused by Vibrio cholerae non-01 which does not produce cholera-like or heat-stable enterotoxins.

An Australian tourist suffering from severe acute watery diarrhoea and dehydration due to Vibrio cholerae non-01 was studied. The V. cholerae strain isolated from the patient belonged to serovar 05. The organism did not produce any of the conventional enterotoxins including cholera-toxin (CT) or heat-stable toxins (NAG-ST) that are known to be associated with intestinal secretion. This report suggests that toxin(s) other than CT-like or NAG-ST may be involved in the pathogenesis of diarrhoea by some V. cholerae non-01 strains.

Acute Disease↗
PubMed1992

Serovar, biotype, phage type, toxigenicity & antibiotic susceptibility patterns of Vibrio cholerae isolated during two consecutive cholera seasons (1989-90) in Calcutta.

Characteristics of V. cholerae isolated from patients of acute secretory diarrhoea admitted to the Infectious Diseases Hospital, Calcutta during two consecutive cholera seasons (1989 and 1990), with special emphasis on biotyping and toxigenicity, were investigated. The isolation rates of V. cholerae during 1989 and 1990 were 78 and 85.1 per cent respectively, with Inaba serotype dominating in 1989 and Ogawa in 1990. All the V. cholerae 01 strains isolated in this study belonged to biotype Eltor with phage type 4 dominating (48.8%). Most of the strains of V. cholerae were resistant to 10 and 150 micrograms/ml of 0/129 vibriostatic agent. Similarly, majority of the V. cholerae strains were resistant to furazolidone (95.7%), cotrimoxazole (83%) and tetracycline (63.1%) and several resistance patterns were encountered. All the V. cholerae 01 strains examined produced cholera toxin (CT) in amounts ranging between greater than 70 pg/ml and greater than 2.5 ng/ml. In contrast, all but one of the non-01 strains isolated in this study did not produce CT. Further studies are required to elucidate the mechanism involved in the pathogenesis of non-01 V. cholerae mediated diarrhoea.

Anti-Bacterial Agents↗
PubMed1991

Direct enzyme-linked immunosorbent assay: a simple immunoassay using Leishmania donovani promastigote for diagnosis of kala-azar.

For immunodiagnosis of kala-azar enzyme-linked immunosorbent assay (ELISA) and immunofluorescence testing (IFAT) are commonly used. In IFAT, whole parasite antigen and in ELISA the soluble antigen have been used. Preparation of ELISA antigen has certain inherent difficulties. We have developed a simple, specific, and quantitative immunoassay, "direct ELISA" for diagnosis of kala-azar. Intact formalinized promastigote suspension has been used to combine with the antibodies of the patient sera. The colour developed in the supernatant by the enzyme conjugate combined on the parasite surface was measured with a spectrophotometer. The test was able to detect kala-azar-specific antibodies at very high serum dilution and could discriminate between kala-azar and the common diseases prevalent in Asia. The optical densities of the sera of different control groups were significantly low. The method has potential for use as a diagnostic tool in less well equipped laboratories.

Animals↗
PubMed1991

Evaluation of direct agglutination test (DAT) and ELISA for serodiagnosis of visceral leishmaniasis in India.

The direct agglutination test (DAT) and the enzyme-linked immunosorbent assay (ELISA) were used for serodiagnosis of parasitologically confirmed Indian visceral leishmaniasis (VL) cases. All the sera of VL cases were positive by both the methods. DAT titres of VL cases were greater than or equal to 1:3,200, and ELISA values were greater than or equal to 0.55 1:400 dilution. In the control group, sera of widely prevalent diseases of India, such as leprosy, tuberculosis, malaria, and liver cirrhosis, were included. Both tests could discriminate between VL and other patients of the control group. The sera of post-kala-azar dermal leishmaniasis (PKDL) patients gave OD values of greater than 0:55 and had DAT titres of 1:1,600. Both tests are sensitive and specific for the diagnosis of VL cases. DAT, being simpler and more economical, will be suitable for diagnosis and epidemiological studies for VL under rural conditions of India.

Agglutination Tests↗
PubMed1990

A novel tubulin from Mimosa pudica. Purification and characterization.

From Mimosa pudica fresh leaves and pulvinar callus cells, we have purified tubulin protein using an anion-exchange resin, DEAE-Sephadex A-50, followed by ammonium sulfate fractionation and Sephadex G-200 gel filtration. The purified protein consisted of alpha and beta subunits and trace quantities of other proteins. When analysed by sodium dodecyl sulfate/polyacrylamide gel electrophoresis at pH 8.8, both alpha and beta subunits of tubulin almost comigrated with their counterparts from goat brain. Two-dimensional electrophoresis revealed that this tubulin contains one major alpha-tubulin having a pI value of 7.1 and three beta species having pI values of 6.70, 6.46 and 6.40. Morphologically normal microtubules were observed by electron microscopy; self-polymerization in vitro, even in the cold, can also be achieved. Radioimmunoassays, and also immunoblotting with the antibodies raised against alpha- and beta-tubulins of this plant, showed that the nature of alpha-tubulin is different from that obtained from other sources. This is an example of plant tubulin where strong colchicine binding at 1 microM was observed. This protein constitutes 5-6% of the total extractable protein in the leaves. We propose that movement of the leaves of this plant may be regulated by the presence of a high amount of this protein.

Blotting, Western↗
PubMed1990

An ELISA for quantitation of tetanus toxin.

A sandwich ELISA for quantitation of tetanus toxin was devised using commercially available horse antitetanus antiserum and its HRP-conjugate. With commercial toxoid as a standard the assay had a lower sensitivity of 100 ng/ml and was linear up to 100 micrograms/ml. In terms of Lf equivalents the ELISA assay was linear from 0.02 to 20 Lf/ml. The Lf activity in 20 preparations of tetanus toxin as determined by ELISA was comparable to the activity measured by conventional flocculation tests (r = 0.987).

Enzyme-Linked Immunosorbent Assay↗
PubMed1990

Cronkhite-Canada syndrome with hypothyroidism.

An elderly man with non-familial gastrointestinal polyposis, malabsorption and progressive hypoproteinemia is reported. Associated alopecia, cutaneous hyperpigmentation and nail dystrophy with loss of nails were consistent with the diagnosis of Cronkhite-Canada syndrome. Hypothyroidism was present in this patient and the rare association of these two conditions is discussed.

Aged↗