Biomedical subjects
S K Chatterjee
Publications and source records attributed to S K Chatterjee.
Molecular cloning of human beta 1,4-galactosyltransferase and expression of catalytic activity of the fusion protein in Escherichia coli.
1. Three groups of cDNA clones (total of six) for human UDP-galactose: beta N-acetylglucosamine galactosyltransferase (4 beta GT) were obtained by screening of a fetal liver library in lambda gt11 with an affinity purified anti4 beta GT antibody. 2. One group of clones (three clones) reacted with two distinct anti4 beta GT murine monoclonal antibodies. 3. Nucleotide sequence of this group of clones were similar to published sequence for human 4 beta GTcDNA, except the 74 nucleotides at the 5'-end. 4. Partially purified fusion protein encoded by this group of clones showed all the catalytic properties of 4 beta GT, although the cDNA was partial and the protein was probably unglycosylated.
Hypoglycemic effect of swerchirin from the hexane fraction of Swertia chirayita.
A xanthone was isolated from the hexane fraction of the Swertia chirayita plant and identified as 1,8-dihydroxy-3,5-dimethoxyxanthone (swerchirin). It has a very significant blood sugar lowering effect in fasted, fed, glucose loaded, and tolbutamide pretreated albino rat models. The ED50 for 40% blood sugar lowering in CF male albino rats (body weight 140-165 g) is 23.1 mg/kg/oral. The possibility of its application in clinical therapy for diabetes mellitus needs exploration.
Role of a large plasmid of Salmonella typhi encoding multiple drug resistance.
Twenty isolates of Salmonella typhi from cases of typhoid during the 1989-1990 epidemic in Calcutta were examined. Most isolates (84% of all isolates in the epidemic) were resistant to chloramphenicol, ampicillin, tetracycline and streptomycin but were sensitive to nalidixic acid and ciprofloxacin. Plasmids of 120 kb and 14 kb were identified amongst the multi-drug resistant isolates of S. typhi. However, there was no plasmid in the antibiotic-sensitive isolates. The 120-kb plasmid was transferable and transconjugants were resistant to chloramphenicol, ampicillin, tetracycline and streptomycin. Restriction endonuclease analysis patterns after EcoRI digestion of the 120-kb antibiotic-resistance plasmids from the S. typhi isolates and transconjugants were similar.
Genetics of epidermal ridges: a study in subjects with refractive errors.
The dermatoglyphic characteristics of subjects with refractive errors when compared with control group revealed significant differences in both qualitative and quantitative parameters. The loops were increased in male myopics; the whorls were increased in male hypermetropics and astigmatics and the arches were decreased in all types of refractive errors in males. However, the whorls were decreased in female hypermetropics only. The mean total ridge count was significantly higher in male astigmatics only. As regards pattern intensity (fingers) no significant difference in the mean value was observed in either sex with any type of refractive errors when compared with those of controls.
Epidemic multiresistant enteric fever in eastern India.
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Surgeons in general and surgery in rural area.
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Effect of hyperthermia on activity of three glycosyltransferases in Chinese hamster ovary cells.
We measured activities of three glycosyltransferases at various times during heat-induced thermotolerance development. Glycosyltransferases are normally located in the Golgi apparatus and catalyze cellular glycosylation reactions. UDP-Gal:N-acetylglucosamine beta 1,4-galactosyltransferase (beta 1,4-GalT) is known to participate in the formation of N-linked glycoproteins; when compared to cell survival, beta 1,4-GalT activity was significantly more heat resistant (50% loss of activity: 80 min, 45 degrees C) and showed little elevation at a time when thermotolerance was fully expressed. However, beta 1,4-GalT activity increased twofold by 24-h postheating when thermotolerance had begun to decay. Activity of beta 1,4-GalT was compared with glycosyltransferase activities that are considered to be specific for O-linked glycoproteins: UDP-Gal:N-acetylgalactosamine-beta 1,3-galactosyltransferase (beta 1,3-GalT), and UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase (Gal-NAcT). Heat-inactivation experiments with heating times up to 60 min at 45 degrees C failed to reduce either activity below that of unheated control cells. Instead both beta 1,3-GalT and GalNAcT activity increased approximately twofold immediately after 10 min at 45 degrees C. Activity of beta 1,3-GalT rapidly decreased with time after heating and returned to control levels by 6-h postheating. In contrast, GalNAcT activity continued to increase with time after 10 min at 45 degrees C, and was 4.5-fold above unheated controls by 6-h postheating. GalNAcT activity returned to control levels 24- to 48-h postheating. A comparison with the cellular survival response showed that GalNAcT activity preceded thermotolerance expression by 2-4 h and also decayed more rapidly than heat resistance in thermotolerant cells. These data, together with other published results, suggest that expression of thermotolerance may be associated with enhanced glycosylation of intracellular proteins.
Idiotype vaccines against human T cell leukemia. II. Generation and characterization of a monoclonal idiotype cascade (Ab1, Ab2, and Ab3).
Previously, we had generated anti-Id mAb (Ab2) binding to a hybridoma SN2 (Ab1), which recognizes a glycoprotein, gp37, expressed by human leukemic T cells. To characterize these anti-idiotopes further, they were used to immunize mice and rabbits. Several murine anti-anti-Idiotype mAb (Ab3), mostly of IgM-k isotype, were obtained. mAb3 and sera from rabbits immunized with Ab2 contained antibodies that bind to gp37 Ag and leukemic MOLT-4 and JM cells. Also, mAb3 and immune sera from rabbits competed with Ab1 for binding to MOLT-4 cells. They inhibited the binding of iodinated Ab1 to Ab2 indicating that Ab3 in mice and rabbits shares idiotopes with Ab1 (SN2). Furthermore, both the murine mAb3 and rabbit polyclonal Ab3 immunoprecipitated the same gp37 Ag as SN2 (Ab1). The production of Ag-specific Ab3 (Ab1') in mice and rabbits in absence of any exposure to gp37 indicates that these Ab2 may indeed carry the internal image of the gp37 Ag. Such anti-idiotopes (Ab2 beta) may be useful as Ag substitute for the induction of therapeutic immunity in T cell leukemia patients.
Staging the separation of ischiopagus twins.
A pair of ischiopagus tetrapus twins were successfully separated in Calcutta in 1986. The separation was staged. The gastrointestinal tracts were separated at a preliminary operation, and definitive separation carried out 3 months later. Staging permitted us to perform the final separation on healthier babies with the exclusion of the intestinal contents from the wounds and with reduced operating time.
An unusual presentation of pneumatocele.
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Lower limb gangrene and paralysis following umbilical cord injection.
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Characterization of the antigen recognized by monoclonal antibody 1D3.
Human ovarian mucinous cystadenocarcinoma-associated antigen recognized by murine monoclonal antibody 1D3 (Bhattacharya et al., 1982) was characterized. Gel filtration and sodium dodecylsulfate polyacrylamide gel electrophoresis, followed by Western-blot analysis showed that 1D3 is a high molecular weight glycoprotein. Isoelectric focusing of 1D3 antigen showed 2 overlapping antigenic components with PI 2.5 and 2.6. 1D3 antigen was extremely stable (10 min at 100 degrees C) to heating. The antigenic activity was slightly stimulated by treatment with galactosidases, but neuraminidase treatment enhanced the antigenic activity about 3-fold. Antigen activity was completely stable to periodate oxidation. Pronase and trypsin treatment completely destroyed the antigenic activity. Properties of 1D3 antigen suggest that this is a high molecular weight (approximately 5-20 x 10(6) Dalton), sialomucin. Monoclonal antibody 1D3 recognizes only the protein part of this molecule.
Can demand for illicit drugs be reduced?
Given the technological advances in communications and logistics systems, as well as the enormous profits derived from illicit drug trafficking, it is most probable that traffickers will in the future attempt to increase both the illicit supply of and demand for drugs. It is also expected that traffickers will manage to produce new addiction-producing substances for the illicit market. In these circumstances, and given the fact that addicts have formed deeply rooted drug-using habits, it appears that the reduction of the illicit demand for drugs can only be achieved by concurrent implementation of both stringent drug law enforcement measures and effective programmes for the prevention of drug abuse and for the treatment, rehabilitation and social reintegration of drug-addicted persons.
Characterization of products synthesized by galactosyltransferase purified from the ascites of ovarian cancer patients.
Galactosyltransferase purified from the ascites of ovarian cancer patients can use to an equal extent N-glycosidic glycoproteins, such as asialoagalactofetuin, and O-glycosidic mucin, such as asialo bovine submaxillary mucin (BSM), as acceptors. Thermal treatment and substrate competition experiments demonstrated that the same enzyme catalyzed the transfer of galactose to both types of acceptors. Alkaline borohydride treatment showed that, while the product with asialoagalactofetuin was totally resistant, about 90% of the product with asialo BSM was hydrolyzed by this treatment. Gel filtration of the released oligosaccharides on a calibrated Biogel P-2 column showed three peaks. One major oligosaccharide (O-2) of size 5.7 glucose U and two minor peaks (O-1 and O-3) of sizes 8.7 and 3.7 glucose U, respectively, were obtained. The oligosaccharides were doubly labeled, first by incubation with uridine-diphosphate [14C]galactose, followed by alkali treatment in the presence of [3H]borohydride. The doubly labeled oligosaccharides were separately purified by gel filtration and ion-exchange chromatography and digested with various exoglycosidases. The digested products were characterized by gel filtration and paper chromatography in three different systems. From these results, the structures of these oligosaccharides were computed as follows: O-1 = beta-galactosyl-beta-N-acetylglucosamine-galactosaminitol (sialic acid); O-2 = beta-galactose-beta-N-acetylglucosamine-galactosaminitol; O-3 = beta-galactose-galactosaminitol. These results suggest that the galactosyltransferase from the ascites of ovarian cancer patients catalyzes the transfer of galactose to N-acetylglucosamine, irrespective of whether it is a part of an N-glycan or an O-glycan.
Silicosis in slate pencil workers: I. An environmental and medical study.
An environmental and medical survey was undertaken in the slate-pencil industry in the central part of India. The industrial hygiene survey revealed that concentrations of free silica dust were very high. The medical survey, involving 593 workers, revealed that the prevalence of silicosis in this industry was 54.6%. Of these, 17.7% of workers had conglomerate silicosis (progressive massive fibrosis, PMF). The radiologic appearance of simple and conglomerate silicosis resembled closely the simple pneumoconiosis and progressive massive fibrosis (PMF) among other occupational groups exposed to free silica and also found in coal workers. The pulmonary lesions were detectable after a relatively short duration of exposure. The short latent period of development and the high prevalence of silicosis observed among these workers are related to exposure to high concentrations of siliceous dust in the work environment.
Production of murine monoclonal antibodies against cell-surface antigens of human ovarian carcinoma.
Splenic lymphocytes of BALB/c mice immunized with human ovarian carcinoma cells were fused with the mouse myeloma cell line, NS-1 in the presence of polyethylene glycol, MW 1500. The hybrid cultures were screened by a viable cell-binding radioimmunoassay (RIA) for the production of relevant antibodies. Hybrids that produced antibodies that bound to the surface of the immunizing cell line and other ovarian carcinoma cell lines, but not to human fibroblast cell lines or erythrocytes and leucocytes isolated from peripheral blood, were cloned twice by the limiting dilution method. Two such clones designated 8C3, of the IgG2a isotype, and 10D6, of the IgG1 isotype, were checked for specificity by a solid-phase membrane RIA. The monoclonal antibodies (MoAbs) recognized an antigenic determinant present on different human adenocarcinomas such as ovary, breast, endometrium, colon, and stomach. The normal counterpart tissues of these histiotypes showed negligible binding to the MoAbs. The relative specificity of these MoAbs encourage further studies towards their characterization and evaluation as possible diagnostic and therapeutic agents in human cancer.
Production and characterization of monoclonal antibody to a 60-kD glycoprotein in ovarian carcinoma.
Monoclonal IgG1 antibodies 2C8 and 2F7, derived by immunization of mice with a glycoprotein-enriched fraction of human ovarian adenocarcinoma, recognized a 60 kD glycoprotein in the ovarian tumor but not in normal ovary. Survey of other normal adult tissues by an indirect solid-phase radioimmunoassay (RIA) revealed the presence of the antigen in trace amounts in various normal organs such as small intestine, liver colon and urinary bladder, except in lung where its concentration was as high as in tumors. Among fetal tissues tested, intestine and placenta had the highest activities. By RIA, about 50% of ovarian and colonic tumors had elevated levels of the antigen. All ovarian cyst fluids, both benign as well as malignant, also contained a high level of the antigen. Immunodepletion studies indicated that the antigen was distinct from carcinoembryonic antigen and the ovarian cancer antigens described in our laboratory with other monoclonal antibodies. The antigen bound to Con A-Sepharose and was eluted with 2% alpha-D-mannoside, was soluble in 0.6 M perchloric acid and stable at 100 degrees C for 30 min. The antigenic activity in isolated plasma membrane enriched fractions of ovarian adenocarcinomas was sensitive to trypsin, chymotrypsin or protease treatment but unaffected by neuraminidase, beta-galactosidase, periodate or methanol treatment. By immunoperoxidase staining, the antigen was localized in a variety of human tumors showing widespread distribution.