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Biomedical subjects

M K Das

Publications and source records attributed to M K Das.

At least 73 records · Page 4Linked to original sources
PubMed1992

Relationship of hypolipidemic and antineoplastic activities of tricyclohexyl- and triphenylphosphine boranes, carboxyboranes, cyanoboranes, and related derivatives.

A series of tricyclohexyl- and triphenylphosphine boranes, carboxyboranes and cyanoboranes were synthesized. These compounds have potent hypolipidemic effects, antineoplastic and antiinflammatory activities in rodents. Furthermore, they demonstrated potent cyctotoxicity against standard human tissue culture lines. The compounds which afforded the best hypolipidemic activity, i.e. greater than 40% reduction of serum cholesterol and triglyceride levels, were diphenyl-(4-methylphenyl)-phosphine borane and triphenylphosphine carboxyborane. Other derivatives demonstrated more potent antineoplastic activity against the Ehrlich ascites carcinoma growth including triphenylphosphine cyanoborane, 2-amino-4-methyl-pyridine cyanoborane and 2-amino-pyridine cyanoborane. Most of the derivatives showed good activity against murine L1210 lymphoid leukemia, Tmolt3 human leukemia, uterine HeLaS cells, and human glioma cell growth. Select compounds were active against colon adenocarcinoma, KB nasopharynx, lung bronchogenic and osteosarcoma cell growth. Tricyclohexyl- and triphenylphosphine boranes and the carboxy derivatives of the latter borane demonstrated good antiinflammatory activity.

Animals↗
PubMed1992

Immunoglobulin E and G4 antibodies to infective larvae in a Wuchereria bancrofti endemic population.

IgE and IgG4 antibodies to infective larval antigen of W. bancrofti were measured by ELISA in filarial sera. IgE level was quite high in both infected and non-infected people living in filariae-endemic regions compared to people from non-endemic yet tropical regions. It was also demonstrated that IgE levels in amicrofilaraemic, normal children were lower compared to those of adults. Similarly IgG4 response in children was found to be reduced. The distribution of skin test (immediate hypersensitivity) reaction to larval antigen was not very extensive in people from endemic regions. Higher proportions of the normal population (39%) exhibited skin test reaction than either asymptomatic microfilaraemics or chronic patients (13% each). Specific IgG4 antibody was highly elevated in the sera of people with asymptomatic microfilaraemia. The rate of IgG4 seropositivity was 83% in microfilaraemic individuals compared to 20% in the normal population.

Adult↗
PubMed1992

Investigations on the variability of blood group polymorphisms among sixteen tribal populations from Orissa, Madhya Pradesh and Maharashtra, India.

Sixteen tribal populations from Orissa, Madhya Pradesh and Maharashtra have been typed for the polymorphic blood group systems A1A2B0, MNSs, Rhesus, Kell, Duffy and Diego. The heterogeneity in the distribution of haplotype and allele frequencies, respectively, is partly considerable. It is supposed that this is due to the operation of several microevolutionary factors, such as genetic drift, social and geographic isolation and gene flow. This is discussed in detail.

Alleles↗
PubMed1992

Genetic study of five populations of Bihar, India.

Four-hundred fifty-nine people, including 106 Santals, 43 Bhuiyas, 107 Sakaldipi Brahmins, 108 Chamars, and 95 Ansari Muslims, of the Giridhi district of Bihar have been tested for transferrin, group-specific component, phosphoglucomutase subtypes, and glyoxalase-I, 6-phosphogluconate dehydrogenase, and adenylate kinase types. Genetic distance estimates by both dendrogram and principal component methods for these 5 populations and the Oraons on the basis of 19 alleles at 6 polymorphic loci indicate 2 major clusters: Brahmins and Muslims, the latter of which is composed of two subclusters (Santals and Bhuiyas, and Oraons and Chamars). The Santal and Bhuiya tribes both speak Mundari, whereas the Oraons speak a Dravidian language. The Chamars, although low-caste Hindus, seem to have a non-Europoid origin, as do the Oraons.

Adenylate Kinase↗
PubMed1991

Epitope mapping of antibodies to acetylcholine receptor alpha subunits using peptides synthesized on polypropylene pegs.

Concurrent synthesis of overlapping octameric peptides corresponding to the sequence of the Torpedo acetylcholine receptor (AChR) alpha subunit has been carried out on polypropylene supports functionalized with primary amino groups according to a method developed by M. Geysen [(1987) J. Immunol. Methods 102, 259-274]. The peptides on the solid supports have been used in an enzyme-linked immunosorbent assay. Interactions of the synthetic peptides with antibodies are then detected without removing them from the solid support. By this procedure, epitopes of both antisera and monoclonal antibodies to the Torpedo acetylcholine receptor, its subunits, and synthetic peptide fragments have been mapped. Both rat and rabbit antisera to the alpha subunit show major epitopes spanning the residues 150-165, 338-345, and 355-366 on the Torpedo AChR alpha subunit. Epitopes of monoclonal antibodies to these major epitopes and to others have been rather precisely mapped by using this technique with peptides of varying lengths. The specificity of several of these mAbs are of interest because they have been used in mapping the transmembrane orientation of the AChR alpha-subunit polypeptide chain.

Amino Acid Sequence↗
PubMed1991

Attachment of A172 human glioblastoma cells affects calcium signalling: a comparison of image cytometry, flow cytometry, and spectrofluorometry.

The intracellular free calcium concentration ([Ca2+]i) of indo-1 loaded A172 human glioblastoma cells stimulated by platelet-derived growth factor (PDGF) was studied in cell suspensions by flow cytometry and spectrofluorometry and in confluent monolayers by laser image cytometry and spectrofluorometry. With all three techniques, the percentage of responsive cells, peak [Ca2+]i, and the duration of response were directly related, and the delay time was inversely related to PDGF dose. The maximum response occurred at a PDGF concentration of about 20 ng/ml. Basal and peak [Ca2+]i did not differ significantly from method to method even though different calibration procedures were used. Cells in suspension monitored by both spectrofluorometry and flow cytometry displayed significantly shorter calcium responses than attached cells. This did not appear to be a direct effect of trypsinization. Spectral analysis of indo-1 in cytoplasm, 40% glycerol, and aqueous solutions showed significant differences in the isosbestic point and quantum efficiency. Calibration of [Ca2+]i with spectrofluorometry is more accurate using the ratio of fluorescence intensities than the fluorescence intensities measured at either 405 or 485 nm.

Calcium↗
PubMed1991

Production of antibodies to dextran using liposome as adjuvant.

The kinetics and nature of the immune response to dextran-BSA entrapped into liposomes was studied in rabbit. The antibody titer in the secondary immunization was found to be higher as compared to that in the primary response. In the primary response antibodies were of both IgG and IgM type but following secondary immunization the IgG level was increased. The conjugate entrapped into liposomes could establish an immunological memory for dextran. In order to eliminate the carrier effect of BSA, dextran was either entrapped or coupled to liposome and the immune response was studied in mice. The results revealed that dextran entrapped into liposomes or coupled to liposome surface induced IgM type immune response and antibody titer did not increase on secondary immunization.

Adjuvants, Immunologic↗
PubMed1991

Evaluation of mosquito fish Gambusia affinis in the control of mosquito breeding in rice fields.

The mosquito control potential of Gambusia affinis, a mosquito fish, was evaluated in rice fields in the Shahjahanpur district of Uttar Pradesh. This fish, at a stocking rate of 5 fishes/sq m, significantly reduced the larval and pupal densities in experimental fields as compared to control fields during the entire observation period of 42 days. Control of mosquito breeding in rice fields through this fish seems to be promising.

Animals↗
PubMed1991

Dextran sulfate induced suppression of Plasmodium berghei parasitaemia.

Effect of dextran sulfate (DS, Mr 500,000) on parasitaemia in mice (Balb/c) infected with erythrocytic stage of P. berghei was investigated. Intraperitoneal injection of DS caused marked suppression of patent parasitaemia and also enhanced the survival time of the infected animals.

Animals↗
PubMed1991

Human natural antibodies to Culex quinquefasciatus: age-dependent occurrence.

The titer of anti-Culex quinquefasciatus antibodies which were mostly of IgG and IgE isotypes was determined in humans living in Wuchereria bancrofti endemic regions. A progressive increase in the titer of antibodies was observed with age. In contrast, sera from people living in regions where the Cx. quinquefasciatus is of low prevalence were found to have markedly reduced IgG and almost zero IgE levels.

Adolescent↗
PubMed1990

The distribution of some serum protein and red cell enzyme polymorphisms in the Koch ethnic group of West Bengal, India.

Three populations (Poliya, Deshi, and Tiyor) of the Koch ethnic group have been studied for the distribution of three serum protein and four red cell enzyme polymorphisms. There was no significant difference in the allelic frequencies of these systems in the three populations of the Koch ethnic group. The overall gene frequencies were as follows: Hp1, 0.21; Gc1F, 0.34; Gc1S, 0.36; Gc2, 0.30; TfC1, 0.66; TfC2, 0.26; TfC3, 0.001; TfD, 0.06; GLO1, 0.21; PGI2, 0.04; AK2, 0.01; PGM1+, 0.80; PGM1-, 0.06; PGM2+, 0.11 and PGM2-, 0.02. The phenotypic distribution at all the loci was at Hardy-Weinberg equilibrium.

Adenylate Kinase↗
PubMed1990

Antibodies to microfilarial sheath in bancroftian filariasis--prevalence and characterization.

Antibodies directed towards the sheaths of microfilariae have been implicated in the elimination of circulating microfilariae, both in experimental and human filariasis. In the present study antisheath antibodies have been detected in human sera by indirect immunoperoxidase assay (IPA) using fixed Wuchereria bancrofti microfilariae as antigen. One hundred and eighteen sera collected from an area endemic for Bancroftian filariasis were tested. While 80% of sera from microfilariae carriers had no demonstrable antisheath antibodies, more than 80% of amicrofilaraemic samples (chronic filariasis cases and endemic normals) had antisheath antibodies. The antibody activity was found in IgG, IgM and also IgE isotypes. IgG subclass typing with monospecific antisera revealed significantly higher antisheath activity in IgG2 in comparison with other IgG subclasses. The determinants on sheathed microfilariae reacting with antisheath antibodies were found to be thermostable (100 degrees C for 30 minutes), resistant to protease treatment and significantly sensitive to sodium periodate treatment, indicating the possible role of carbohydrate moieties in eliciting protective antisheath antibodies in Bancroftian filariasis.

Animals↗
PubMed1990

An experience with diagnostic paracentesis in 100 cases of acute abdomen.

Prognosis of acute surgical conditions of abdomen of both traumatic and non-traumatic origin depends on accurate diagnosis and early surgical intervention. However, the diagnosis in acute abdomen is quite difficult. The problem becomes more complex when 24 hours services of radiology and laboratories are not available. Abdominal tap gives a valuable clue to diagnosis. A 10 ml syringe fitted with a 20 gauge intravenous needle was used for the purpose. Both the flanks and the four quadrants of the abdomen were selected for site of the tap according to the suspected pathology. Results were indicated as positive when abnormal fluid (clear, turbid, purulent, bloody, serosanguinous, bile stained and urine, etc) were aspirated. Accurate diagnosis were made in 84.3% in blunt abdominal trauma and 76.47% in non-traumatic acute abdomen. High incidence of accurate results were obtained in gastroduodenal perforations (92%), ruptured ectopic gestation (100%) and burst amoebic liver abscess (100%). The procedure is very simple which could be done at bed side without much disturbance to the severely ill patients. It is safe and free from any complications even if the bowel is also punctured during the tap.

Abdomen, Acute↗
PubMed1989

The main immunogenic region of the nicotinic acetylcholine receptor: interaction of monoclonal antibodies with synthetic peptides.

Monoclonal antibodies to the main immunogenic region of the nicotinic acetylcholine receptor have been studied with regard to their binding to synthetic peptides. It was found that monoclonal antibody 210 to the main immunogenic region binds to the synthetic fragment spanning residues 66 to 76 of the alpha subunits of the acetylcholine receptor from human muscle, but not to the homologous sequence from Xenopus. This parallels the reactivities of antibodies to the main immunogenic region with intact receptors from two species, and confirms the biological significance of the weak interactions observed between antibodies to this region and synthetic peptides. It also suggests that N alpha 68 and D alpha 71 are critical contact residues.

Animals↗
PubMed1988

Naturally-occurring anti-alpha-galactosyl antibodies in human Plasmodium falciparum infections--a possible role for autoantibodies in malaria.

Naturally-occurring antibodies with a distinct alpha-galactosyl specificity (anti-gal) have been earlier implicated in opsonization and elimination of human senescent erythrocytes from circulation. In the present study a cell-ELISA was developed for quantification of anti-gal antibodies in human sera. Using the test, titres of anti-gal were found to be significantly elevated in many of the sera collected from subjects living in malaria endemic areas or patients with acute Plasmodium falciparum malaria, in comparison to the titres in subjects living in areas where the incidence of P. falciparum malaria was scarce. IgG subclass typing by cell-ELISA revealed IgG3 to be the predominant type with anti-gal activity in P. falciparum infected patients' serum while IgG2 was found to be dominant in the non-endemic control serum. These findings appear to have implications in P. falciparum malaria, since putative antigens with alpha-galactosyl determinants have been identified in the erythrocytic stage parasites of P. falciparum.

Animals↗