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Biomedical subjects

A Bhattacharya

Publications and source records attributed to A Bhattacharya.

At least 217 records · Page 12Linked to original sources
PubMed1986

Analysis of the organization and nucleotide sequence of the chromosomal gene for the beta-subunit of rat thyrotropin.

The gene for the beta-subunit of rat thyrotropin has been isolated from a library of rat DNA fragments cloned in bacteriophage lambda. The complete nucleotide sequence of the gene has been determined including a portion of 5'- and 3'-flanking regions. The rat TSH-beta gene contains approximately 4879 nucleotides which ultimately lead to the production of a mRNA of about 554 nucleotides, exclusive of the 3' poly(A) tract. The first exon which represents only 5' untranslated sequences of the mRNA, is separated from the second exon by a very large, 3.9-kbp intervening sequence. The second and third exons are separated by a small, 377-bp intervening sequence. Southern blot analysis of total genomic DNA demonstrated that the rat genome contains sequences similar to the cloned gene, suggesting that no rearrangements occurred during the cloning process.

Animals↗
PubMed1986

Antibody-based enzyme-linked immunosorbent assay for determination of immune complexes in clinical tuberculosis.

Immune complexes were isolated from sera of tuberculosis patients by precipitation with 2.5% polyethylene glycol. The precipitates were characterized by quantitative determination of different immunoglobulin classes by single radioimmunodiffusion, sodium dodecyl sulfate polyacrylamide gel electrophoresis for presence of serum components, Ouchterlony's double diffusion method for detection of complement components C3 and C4, and immuno-dot assay for detection of Mycobacterium tuberculosis antigens. The results showed that polyethylene glycol precipitates of patients' sera were indeed immune complexes, as they contained immunoglobulins, albumin, complement components, and mycobacterial antigens, whereas precipitates from control sera contained mainly albumin. The antibodies present in immune complexes were specific to M. tuberculosis antigen and showed no binding to Escherichia coli antigens. Immune complex levels, as determined by the ability to bind M. tuberculosis antigens in an enzyme-linked immunosorbent assay, were significantly higher in tuberculosis patients (n = 22) than in healthy control subjects (n = 18). Thus, immune complex level could be a useful parameter in the diagnosis of active tuberculosis.

Antibodies↗
PubMed1986

Mechanism of phagocytosis of mycobacteria by Schwann cells and their comparison with macrophages.

Factors influencing the phagocytosis of mycobacteria by 33B rat Schwannoma cells and rat peritoneal macrophages were studied. Uptake of 14C-acetate-labeled Mycobacterium w by these cells was used to set up a radiometric phagocytosis assay. Incubation at 4 degrees C and treatment with sodium azide (0.2% to 1%), colchicine (10(-7) to 10(-3) M), cytochalasin B (0.2 micrograms/ml to 25 micrograms/ml), and dibutyryl cyclic AMP (10(-7) to 10(-3) M) inhibited the phagocytosis by both cell types in a similar manner. These experiments demonstrate similarities in the mechanism of phagocytosis of mycobacteria by Schwann cells and macrophages.

Animals↗
PubMed1986

Lack of Mycobacterium leprae-specific uptake in Schwann cells.

Among mycobacteria, Mycobacterium leprae have a unique property to infect peripheral nerves, which is the cause of a variety of debilities seen in leprosy. The possibility of selective uptake of M. leprae by Schwann cells was studied using a rat Schwannoma cell line 33B and rat sciatic nerve-derived Schwann cells. M. leprae were phagocytosed by 33B cells but so also were seven other mycobacteria ("Mycobacterium w," BCG, M. tuberculosis H37Rv, M. nonchromogenicum, M. vaccae, ICRC bacillus, and M. smegmatis) which do not involve peripheral nerves. All three mycobacteria tested (M. leprae, M. tuberculosis and "Mycobacterium w") were phagocytosed by sciatic nerve-derived Schwann cells. Both Schwannoma and Schwann cells phagocytosed even inert latex particles. These results fail to demonstrate any M. leprae-specific uptake system in Schwann cells.

Adhesiveness↗
PubMed1986

Humoral immune response in tuberculosis: initial characterization by immunoprecipitation of 125iodine labelled antigens and sodium dodecyl sulfate polyacrylamide gel electrophoresis.

125Iodine-labelled Mycobacterium tuberculosis antigens were immunoprecipitated with tuberculosis patients' sera and analysed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. A group of four polypeptide antigens of 55, 38, 28 and 18 kD were thus identified. The 38 and 28 kD polypeptides were the major antigens. Antibody response differed from one patient to another, both with respect to the number and quantity of antigens precipitated. Untreated patients and those undergoing treatment with antimycobacterial drugs also showed marked differences in their antibody response. Generally, immunoprecipitates from treated patients showed a larger number of antigen bands and the relative intensities of the bands was also greater. No correlation was observed between the immunoprecipitation profile and antibody titres determined by enzyme linked immunosorbent assay.

Antibodies, Bacterial↗
PubMed1986

Shock.

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Child↗
PubMed1985

Novel application of quantitative immunoassays for screening seed globulins of cowpea varieties.

Using antibodies raised in rabbits, radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) are standardized for cowpea (var. Pusa Barsati) seed globulins. The RIA, when used to screen three stages of seed development, reveals that maximum globulins are detected at 28 days after flowering. When three different varieties of cowpea are assayed for their globulin content by RIA and ELISA, it is observed that the Bold Grain cowpea has the highest amount of related globulin as compared to two other varieties, namely Pusa Phalgun and Asparagus Bean.

Electrophoresis, Polyacrylamide Gel↗
PubMed1985

Traumatogenic factors affecting the knees of carpet installers.

An ergonomics analysis of carpet installation tasks was performed. The purpose was to identify and quality potential sources of biomechanical trauma that may be responsible for the high rates of knee morbidity found by previous researchers among carpet layers. Nine carpet layers were studied either at an apartment building worksite or at a training school. Results from a job analysis indicated that workers spent approximately 75% of their time in the kneeling position using a tool called a knee-kicker to stretch and install carpet. Awkward body postures were identified from films of workers installing carpets. At the moment of impact the knee is severely flexed, subtended angles were less than 60 degrees. To obtain measures of impact force on the knee, the kicker-tool was instrumented with a load cell. Workers who executed the hardest kicks with the tool produced impact peak forces that averaged 3019 newtons (N), which is equivalent to about four times body weight. Measures from an accelerometer attached to the worker's knee showed values in excess of 120 m/s(2), which are comparable to those found during vigorous running and jumping exercises. The results imply that repetitive impact of the knee joint from the use of the knee-kicker combined with knee flexion, kneeling and squatting may be responsible for the high level of occupational knee-morbidity found among carpet layers.

Journal Article↗
PubMed1985

Isolation, characterization, and regulation of the prolactin receptor.

The prolactin, or lactogenic hormone, receptor has been purified (approximately 80%) from lactating mouse liver and human term placenta by the nondenaturing zwitterionic detergent 3-[(3-cholamidopropyl)-dimethylammonio]-1-propane sulfonate and a prolactin affinity column. The isolated "core-binding unit" has a molecular weight of 37,000 +/- 2,000 daltons. It retains the specificity for lactogenic hormones and binds prolactin with an affinity (Ka = 2 to 6 X 10(9) M-1) similar to that of the receptor as it occurs in its membranous environment (Ka = 3 to 5 X 10(9) M-1). Whether this "core-binding unit" exists on the cell surface in a cryptic or active form is influenced greatly by its association with other membrane proteins and the concentration of phosphatidylcholine within its local membranous environment.

Animals↗
PubMed1984

Effects of exercise using industrial respirators.

Respirators (respiratory personal protective devices), used for protection against occupational toxic exposures, may impose flow resistance and dead space respiratory loading. Effects of exercise level, a 300 mL deadspace and single respirator cartridge inspiratory load were determined in ten healthy volunteers. Subjects tended to limit peak work rate (pressure generated and pressure X flow) and to prolong the inspiratory portion of the respiratory cycle due to respirator use. O2 consumption and heart rate were not significantly affected. The qualitative response was not affected by exercise level. During submaximal exercise, normal subjects did not reach their compensation limits for the variables studied.

Heart Rate↗
PubMed1982

Determination of critical anthropometric parameters for design of respirators.

The objectives of this study were 1) to collect useful anthropometric data from 243 workers fit-tested in a continuing respirator fit-test program; and 2) to determine correlation between anthropometric data and Protection Factor obtained from quantitative fit-testing for half-mask respirators. Anthropometric data were collected from two direct facial measurements [nasal root breadth (NRB), and face-length (FL)] and five indirect facial measurements [nose length, nose protrusion, chin length, mouth width (MW), and face width (FW)] from front- and side-view slides of test subjects. For quantitative analysis, the anthropometric data collected in this study were normalized with relevant respirator dimensions (for four different brands and ten sizes). Results of linear regression analysis indicated that correlation coefficients between Protection Factor and anthropometric data (FL, MW, FW and NRB) were respectively - 0.04, 0.22, 0.30 and 0.04. These correlation coefficients are for white males without facial hair. The "critical" anthropometric parameters as apparent from the analysis were MW and FW. However, a person with certain combination(s) of multiple anthropometric parameters may provide a better correlation with Protection Factor.

Anthropometry↗
PubMed1982

Monoclonal antibodies specific for rat IgG1, IgG2a, and IgG2b subclasses, and kappa chain monotypic and allotypic determinants: reagents for use with rat monoclonal antibodies.

Mouse monoclonal antibodies to rat IgG were obtained by fusion of immune SJL mouse spleen cells to NSI myeloma cells. Seven monoclonal antibodies have been labeled with 125I and studied as to specificity and avidity by using a panel of rat monoclonal antibodies both as inhibitors and target antigens in soft well plate and indirect cell binding assays. All MAb were selected for high avidity of 4 X 10(7) to greater than or equal to 2 X 10(9) M-1. Four MAb were subclass-specific. RG11/39, RG7/1, and RG7/11 were absolutely specific for the Fc' region of IgG1, IgG2a, and IgG2b, respectively. RG9/6 showed specificity for the Fab' region of IgG2a but crossreacted with lower avidity with IgG2c. Three MAb reacted with rat kappa chains. RG7/9 defined a monotypic (common) kappa chain determinant. RG11/15 and RG7/7 were specific for allelic kappa 1a and kappa 1b determinants, respectively. The monotypic and kappa 1a allotypic determinants are topographically separated. The antibodies can be used as screening reagents in indirect cell binding assays. They have sensitivity similar to affinity-purified rabbit anti-rat IgG and more defined specificity. They do not crossreact with mouse or human IgG, making them particularly suitable companion reagents for rat anti-mouse or anti-human MAb. One Mab, RG7/7, strongly crossreacts with Syrian hamster IgG.

Animals↗