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Biomedical subjects

D Basu

Publications and source records attributed to D Basu.

At least 19 recordsLinked to original sources
PubMed1992

A logistic model for thyroid lesions.

A stepwise logistic regression analysis was performed in 27 cases of papillary carcinoma thyroid (PC), 20 follicular neoplasms (FN), 30 cases of Grave's disease (GD), and 40 cases of colloid adenomatous goitre (CAG). The three most important variables in predicting PC were papillary clusters, dense cytoplasm, and intranuclear cytoplasmic inclusions, whereas the predictors of FN were high cellularity combined with a prominent acinar pattern. A few cases of GD and CAG showed a cytologic overlap with PC and FN, respectively. Regression analysis established high cellularity, fire flare appearance, and epitheloid granulomas as reliable predictors of GD, whereas abundant colloid with or without foam cells and follicles associated with colloid (FAC) were important variables in CAG.

Adenocarcinoma↗
PubMed1992

Leaching of concanavalin A during affinity chromatographic isolation of cell surface glycoproteins from human fetal neurons and glial cells.

Preparation of surface glycoproteins from human fetal brain cells by affinity chromatography on Con A-Sepharose 4B was a problematic endeavor due to leaching of Con A from the matrix. Dissociation of Con A from the matrix took place irrespective of the presence of lipid and/or detergent and the buffer composition during chromatography and was apparently related to the nature of the protein under study. Pretreatment of Con A-Sepharose with 6 M guanidine or 8 M urea reduced Con A leaching. The Con A eluate also contained noncovalently associated glycolipid. Elution at 25 degrees C rendered fractions containing a higher degree of Con A and glycolipid contamination compared to the negligible contamination by these two components when elution was carried out at 4 degrees C. This phenomenon was attributed to the formation of heterogeneous mixed micelles of glycoprotein.

Brain↗
PubMed1992

Rapid and sensitive detection of Leishmania kinetoplast DNA from spleen and blood samples of kala-azar patients.

Following sequence analysis of a Leishmania donovani kinetoplast DNA (kDNA) minicircle, we have developed synthetic oligonucleotides for use in the polymerase chain reaction (PCR). With these primers, we have amplified L. donovani kDNA from splenic aspirates and blood samples taken from kala-azar patients. Treatment of the samples for PCR requires only limited DNA purification by lysis in SDS, digestion with proteinase K, phenol extraction and ethanol precipitation of the resulting nucleic acid. We have obtained amplified product routinely with DNA prepared from the equivalent of 2.5-25 microliters of splenic aspirate or of 50-500 microliters of blood from infected patients. In dilution experiments a visible product has been obtained on amplification of DNA from the equivalent of 2.5 x 10(-7) microliters of splenic material. We therefore propose the amplification of L. donovani kDNA by PCR as a rapid and highly sensitive method for the diagnosis of kala-azar.

Animals↗
PubMed1992

Human brain creatine kinase binding to immobilized cibacron blue F3GA: characterization and use in purification of the enzyme.

Creatine kinase (ATP: creatine N-phosphotransferase, EC 2.7.3.2) from adult human brain grey matter was purified by cibacron blue F3GA-Sepharose affinity chromatography. By gel electrophoresis of the purified enzyme under non-denaturing conditions a single protein band was observed. The dye-bound enzyme was eluted using its substrate, ATP. Reversibility of the binding of purified creatine kinase to blue Sepharose by ATP in a concentration-dependent manner indicated that the cibacron blue molecule which structurally mimics nucleotides occupied the substrate binding site of the enzyme. Also the marked dependence of enzyme binding to blue Sepharose on Mg2+ concentration suggested that Mg2+ ion is capable of combining with the dye moiety to form a site-specific binding complex that is similar to the physiological substrate of creatine kinase, namely Mg(2+)-ATP or Mg(2+)-ADP.

Animals↗
PubMed1992

Characterization of concanavalin A-binding neuronal and glial surface glycoproteins from human foetal brain.

Neuronal and glial surface glycoproteins have been isolated from human foetal brains by affinity chromatography on 8 M urea or 6 M guanidine-treated Con A-Sepharose 4B at 4 degrees C and three groups of glycoproteins of molecular mass 65-73 kDa, 52-63 kDa and 43-48 kDa have been identified on SDS/PAGE. These glycoproteins exhibited anomalous behaviour on SDS/PAGE, indicating the existence of a gradation of mutually interconvertible protein-SDS aggregates in dynamic equilibrium with one another. Deglycosylation and deacylation did not alter the SDS/PAGE multiple band pattern. Purified glycoproteins contained 160 +/- 90 micrograms carbohydrate/mg protein, and a sialic acid content of 25 +/- 5 nmole/mg protein. The N-terminals were blocked. The glycoproteins moved preferentially on acid/urea/PAGE. Sepharose 6B gel filtration in the absence of lipid and detergents resolved the glycoproteins into an excluded peak I and a low molecular mass peak II. Peaks I and II were non-interconvertible on Sepharose 6B gel filtration or on reversed phase HPLC in an isopropanol/water/TFA gradient system. Both peaks rendered a single fast moving band of identical mobility on acid/urea/PAGE, suggesting that peak I was possibly a micellar aggregate of the monomeric peak II. The glycoproteins were refractory to digestion by trypsin or pronase and reacted identically towards various lectins.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
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↗
PubMed1991

Isolation and cloning of Bacillus thuringiensis var Kurstaki HD73 toxin gene and construction of a chimaeric gene for expression in plants.

Necessity for the production of transgenic crop plants of India, capable of expression of insecticidal Bt protein in plant to combat lepidopteran pest damage has been strongly felt. Bacillus thuringiensis Kurstaki HD73 crystal protein coded by CryIA(c)73 gene has been found to be sufficiently effective against the major pests of jute and chickpea. An attempt to isolate the gene and make its use in a chimaeric gene construct for expression in plant was carried out. The plasmid CryIA(c)73 gene was cloned and tailored at the 3' end. The expression of the truncated gene was monitored in the minicell systems of E. coli. The entomocidal property was found to be fully retained by the gene product. Deletion of the nucleotides at the 5' end was carried out and chimaeric gene construct of cryIA(c)73 was made in such a way that it was fused in frame with GUS gene under the control of the caMV 35S promoter with Nos polyadenylated terminus. Such a chimaeric gene construct was used as the passenger of a Ti plasmid derived plant vector with kanamycin gene (NPTII) as the additional plant marker. Transformation through infection of tobacco and mustard plant cells in culture was carried out. Plants regenerated from the transformed cells showed the presence of GUS gene indicating the expression of the cloned fused gene. Also, Northern analysis established the presence of cryIA(c)73 gene transcripts in the transgenic plants.

Bacillus thuringiensis↗
PubMed1991

Interaction of T-DNA border sequences and Ti-plasmid vir functions of Agrobacterium results in differential single-stranded linear T-DNA molecule production and plant transformation.

The mechanism of Agrobacterium mediated genetic transformation of plants is dependent upon certain genetic function of the chromosome of the bacterium as well as on Ti-plasmid borne vir loci and the border sequences of T-DNA. The organisationally variable forms of the naturally occurring border sequences amongst Ti-plasmid types are differentially responsive to gene products of vir loci concerned with T-strand production. Additionally, the production of stable transformants is dependent upon vir gene products effective after T strands are produced. The interaction of border sequences from different strains of Agrobacterium with vir proteins encoded by various helper plasmids revealed that functional differences do exist amongst vir gene products contained in the type of helper plasmids used.

Base Sequence↗
PubMed1990

Failure of benzene and phenol to serve as substrates for the peroxidatic action of catalase.

Evidence from several reports in the literature indicates a possible role for catalase in the metabolism of benzene. To investigate possible peroxidatic activity of catalase on benzene or its major metabolite, phenol, we employed an in vitro assay system that had been used previously to study the peroxidation of ethanol by catalase. Under conditions identical to those used to demonstrate catalase-mediated ethanol peroxidation we observed no peroxidase activity of catalase toward either benzene or phenol. We conclude that catalase is not involved in benzene metabolism and make the observation that, to date, no aromatic compounds have been demonstrated to be substrates for the peroxidatic mode of action of catalase.

Animals↗
PubMed1989

Application of the least-squares method in the matrix form: simultaneous spectrophotometric determination of rifampicin and isoniazid in binary pharmaceutical formulations.

A least-squares method in the matrix form is described for the simultaneous determination of rifampicin and isoniazid in a mixture. The method allows the rapid analysis of binary pharmaceutical formulations with minimum error. The concentration of each component in the mixture has been determined spectrophotometrically by measuring the absorbance of the mixture at 5-nm intervals from 230 to 290 nm. To calculate the matrix of the proportionality constant a standard mixture was used for each component. All data analyses were performed on a personal computer.

Isoniazid↗
PubMed1989

Alpha-galactoside-binding isolectins from wild jack fruit seed (Artocarpus hirsuta): purification and properties.

Five isolectins with marked specificity for alpha-linked galactose were purified from the wild jack (Artocarpus hirsuta) seeds by affinity chromatography on cross-linked guar gum. They were composed of a glycosylated subunit A (Mr = 16 kDa) and a nonglycosylated subunit B (Mr = 11 kDa) in noncovalent association. The isolectins which eluted as a single peak of Mr 45 kDa on gel filtration in Biogel P-100 and in a TSK G-3000 SW high pressure column, were resolved into five peaks on electrophoresis at pH 4.5. Sodium dodecyl sulphate polyacrylamide gel electrophoreogram of the major isolectin band suggested that the isolectins may be the five possible tetrameric combinations of A and B subunits. The combined isolectins bound only two molecules of 4-methyl umbelliferyl alpha-D-galactoside with a binding constant of 4.75 x 10(4) M-1. The pH optimum of sugar binding was 7.0. The isolectins specifically bound to human IgG and IgA but not to IgM.

Electrophoresis↗