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Biomedical subjects

S Sengupta

Publications and source records attributed to S Sengupta.

At least 235 records · Page 13Linked to original sources
PubMed1981

Detection of human, rat and mouse adenosine deaminase by immunochemical and immunomorphologic methods using antiserum to calf enzyme.

A commercial preparation of calf adenosine deaminase (calf ADA) was further purified by affinity chromatography and used for immunization of rabbits. The resulting anti-calf-ADA sera reacted by immunodiffusion with both calf and human ADA, and precipitated about 90% of radiolabeled enzyme isolated from human thymus tissue. Moreover, ADA activity was detected in the pellets formed by immunoprecipitation of unlabeled human enzyme by anti-calf-ADA sera. These antisera were successfully used for the immunomorphologic localization of ADA in human thymus tissue and in lymphoid cell preparations. The anti-calf ADA sera could also be used for the immunofluorescent detection of enzyme in rat and mouse thymocytes. The utilization of anti-calf-ADA serum for immunochemical and immunomorphologic detection of enzyme provides a valuable and sensitive reagent for the identification of ADA-positive cells in humans and several other species.

Adenosine Deaminase↗
PubMed1981

Modulation of human T-cell differentiation markers by 12-O-tetradecanoylphorbol-13-acetate.

The analysis of seven differentiation markers following incubation with the tumor promotor 12-O-tetradecanoylphorbol-13-acetate (TPA) was examined in the human leukemic T-cell line MOLT-3. Significant changes were observed in the activity of the markers terminal deoxynucleotidyl transferase (TdT). spontaneous proliferation and the ability of these cells to bind sheep erythrocytes. Levels of human thymus-leukemia-associated antigen (HThy-L) recently identified as a low molecular weight form of adenosine deaminase (ADA), were reduced by about 50%. No significant changes were observed in ecto-5'-nucleotidase [5'-NT) activities, in the proliferative response to PHA, or in the expression of IA-like antigens. These data and the time kinetics of the changes suggest that following incubation of these T-lymphoblasts with TPA there is a sequential loss of TdT, loss of the capacity for spontaneous proliferation, and the appearance of receptors for sheep erythrocytes. Subsequently there is a decrease in the level of HThy-L/ADA. This sequence appears to follow that proposed for prethymic precursor T-cell differentiation following activation with thymic epithelium.

5'-Nucleotidase↗
PubMed1980

Purification and properties of xylan hydrolase from mushroom Termitomyces clypeatus.

The endoxylanase (1,4-beta-D-xylan xylanohydrolase, EC 3.2.1.8) from the culture filtrate of a mushroom, Termitomyces clypeatus, has been purified 93-fold by ammonium sulphate precipitation, ion-exchange chromatography (DEAE-Sephadex) and gel permeation chromatography (Bio-Gel P-200). The enzyme preparation gave a single protein band on disc gel electrophoresis at pH 9.5, and has a molecular weight of approx. 90 000. It also acts on amylopectin, arabinoxyland and arabinogalactan. The enzyme shows maximum activity on xylan (1,4-beta-linked D-xylopyranose units) at pH 55.5 and at 55 degrees C and is fairly stable between pH 3 and 10 and temperatures up to 60 degrees C. The Km is 4 mg of xylan/ml. Hg2+ is the most potent inhibitor, whereas Fe2+, Ag+, iodoacetate and phosphate moderately inhibit the enzyme activity.

Basidiomycota↗
PubMed1979

Pseudotypes of vesicular stomatitis virus and Pichinde virus.

Super-infection of Pichinde virus-infected cells with vesicular stomatitis virus (VSV) resulted in the production of pseudotype virus which was not neutralized by antiserum to VSV but which was neutralized by antiserum to Pichinde virus. Analysis of pseudotype virus production in relation to the kinetics of replication of Pichinde virus demonstrated that pseudotype virus production occurred when super-infection with VSV was initiated 8 h or more after infecting the cells with Pichinde virus. The quantities of pseudotype virus produced correlated with the quantities of Pichinde virus antigen detected on the surface of the cells both during acute infection and in cells chronically infected with Pichinde virus. The observations indicate that pseudotype of VSV and Pichinde virus are readily formed and that the formation of pseudotype virus may be used to examine the Pichinde virus antigens expressed on the surface of infected cells.

Antigens, Viral↗
PubMed1979

Effect of vitamin C on the mitotic activity and follicular growth of the thyroid gland of juvenile pigeon.

The present investigation aims to ascertain the role of vitamin C upon thyroidal activity in immature pigeons. Thyroid follicular function was assessed by karyodynamic and histometric studies. Administration of vitamin C increased mitotic figures as well as epithelial thickeness in the follicles in both sexes of the birds. It is suggested that vitamin C has a mitosis inducing action upon the thyroid gland in juvenile pigeons.

Animals↗
PubMed1978

Photostimulated thermoluminescence of Al2O3 (Si, Ti) and its application to ultraviolet radiation dosimetry.

Intrinsic photostimulated thermoluminescence (PSTL) in the range 200-320 nm and radiation sensitized PSTL for 200-425 nm have been studied in Al2O3 (Si, Ti) phosphor. Causes of the effects found, partly attributed to phototransfer of electrons are described. Linearity in the intrinsic and radiation sensitized response of the 280 degree C TL peal for both pellet and powder forms has been studied with regard to ultraviolet dosimetry over the range 10(-2) to 5 x 10(4) mJ cm-2. Details of the use of powder and pellet forms for dosimetry are given.

Aluminum↗
PubMed1978

Muscle spindles in the inferior constrictor pharyngis muscle of the crab-eating monkey (Macaca irus).

Pharyngeal muscles were considered to be lacking in spindles. A search was made for the same in the inferior constrictor pharyngis muscle of the crab-eating monkey (Macaca irus). Muscle spindles were found for the first time in this muscle. Transverse serial sections and teased preparations were obtained from this muscle belonging to six such animals, and these tissues were stained by Masson's trichrome and Ranvier's gold method, respectively. Both the methods were successful in revealing these receptors. The potential significance of this finding was discussed in relation to the activities of the pharyngeal muscles and a suggestion for a thorough re-investigation of the so-called spindleless muscles was made.

Animals↗
PubMed1978

Immunological studies in psoriasis.

The mean values of serum immunoglobulins A, G, M and D levels in 42 psoriasis patients showed no significant difference from those of control subjects. Analysis of the same sera for the presence of antiglobulin antibodies also yielded negative results. Antinuclear factor could be demonstrated in only 4.8% of the cases. The possibility that serum antiglobulins get drained into the lesions making their detection in the serum difficult, is supported by our preliminary findings of focal deposition in the stratum corneum of immune complexes of IgG, IgM and complement in tissue sections of psoriatic lesions from these patients.

Adolescent↗