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Biomedical subjects

M Kubo

Publications and source records attributed to M Kubo.

At least 631 records · Page 35Linked to original sources
PubMed1981

Developmental changes in humoral suppressor activity released from concanavalin A-stimulated human lymphocytes on B cell differentiation.

Cell-free culture supernatants (Con A-activated supernatants) were obtained by incubating peripheral blood lymphocytes (PBL) from cord blood, healthy children of various ages, and healthy adults with mitogenic doses of concanavalin A (Con A) for 48 hr. It is well known that human T lymphocytes are activated by Con A to manifest suppressor function in vitro. One mechanism whereby these suppressor cells act has been shown to be by the secretion of a soluble suppressor factor. The present study has investigated the Con A-inducible suppressor cell function in cord blood, children of various ages, and adults by comparing the ability of each Con A-activated supernatant to inhibit the generation of immunoglobulin-producing cells (Ig-PC) in pokeweed mitogen- (PWM) stimulated cultures of adult PBL. Con A-activated supernatants from adults could markedly suppress the generation of Ig-PC by allogeneic as well as autologous PBL in response to PWM. Such suppression appeared to be equally effective on the generation of IG-PC of 3 major classes, IgG, IgM, and IgA. On the contrary, Con A-activated supernatants from cord blood and newborn infants showed only a negligible suppression on PWM-induced adult B cell differentiation. But the suppressor activity found in Con A-activated supernatants gradually increased with advancing age, and reached approximately to the adult level at 4 yr of age or later. The results suggest that human T lymphocytes may be relatively deficient in their Con A-induced suppressor cell function in the early period of life.

Adult↗
PubMed1981

Morphology of sulfur granules produced by Pseudomonas aeruginosa in cows.

A sulfur granule produced by Pseudomonas aeruginosa in three cows was studied light- and electron-microscopically. It consisted of clumps of basophilic bacteria and eosinophilic clubs. The clubs radiated from the periphery outward. The bacteria were stained dark red by both PAS and MacCallum-Goodpasture staining. Electron-microscopically, the sulfur granule consisted of electron-dense amorphous material and bacteria. The intact bacterium was about 0.45 micrometers in diameter and had an electron-dense cell wall 15 nm in width. Beneath the cell wall, moderately electron-dense fine granular material was present. The center of the bacterium was electron lucent. The club was electron-dense amorphous material. Degenerative bacteria and pilus-like structures were often seen in it. In one case, clusters of bacteriophages were present in and near the degenerative bacteria. Their head was hexagonal and 40 nm in diameter.

Animals↗
PubMed1981

Electron microscopy of cells cultured in serum-free medium after inoculation of swine vesicular disease virus.

Morphological alterations of IB-RS-2 cells cultured in serum-free maintenance medium after inoculation of swine vesicular disease virus (SVDV) were studied electron-microscopically. Cells harvested 0 to 3 hours after inoculation showed no alterations. Cellular alterations were observed from 4 to 7 hours after inoculation. Many vacuoles appeared just beneath the cytoplasmic membrane and were separated by thin cytoplasm. Narrow pathways were sometimes seen in the degenerative cells. They occasionally ran from the vacuole just beneath the cytoplasmic membrane to the nuclear cistern. Ribosome-like granules were seen along the narrow pathway or diffusely in the cytoplasm, or accumulated to form an islet. Membrane-bound bodies were frequently noticed in the central region of the cell. Cytoplasmic blebs were sometimes seen projecting from the cell surface. Vacuoles, narrow pathways and cytoplasmic blebs were absent in cells cultured in the medium with serum. So serum might exert some effects on the cytoplasmic membrane or cytoskeletal framework. Crystalline arrays of SVDV were found in the cytoplasm of degenerative cells harvested from 4 to 7 hours after inoculation. They were near the ribosome-like granules and membrane-bound bodies, but had no relationship with vacuoles just beneath the cytoplasmic membrane and narrow pathway. Their size and morphology were the same as those seen in the cells cultured in the medium with serum.

Animals↗
PubMed1980

Specific modification of hepatic triglyceride lipase activity by ultracentrifugally separated serum lipoprotein fractions.

Hepatic triglyceride lipase (H-TGL) obtained from postheparin plasma is first stimulated and than progressively inhibited by addition of an increasing amount of serum. To solve the mechanism of this modification, serum fractions isolated by ultracentrifugation were added to the assay mixture and their effects on H-TGL activity were determined. We demonstrated that the addition of the d=1.21 bottom fraction together with HDL almost fully reproduces the effect of the whole serum.

Heparin↗
PubMed1980

Crystal formation of swine vesicular disease virus in porcine kidney cells (IB-RS-2 cells).

Crystal formation of swine vesicular disease virus (SVDV) in IB-RS-2 cells was studied by electron microscopy. Cells were harvested 0, 3, 3.5, 4, 4.5, 5, 6 and 7 hours after inoculation. Crystalline arrays of SVDV was first observed in the cytoplasm of a few cells 4.5 hours after inoculation. In the cytoplasm of many cells harvested at 5 hours, 1 to 3 crystalline arrays of SVDV were observed. After that, a small number of cells had crystalline arrays in the cytoplasm. The cells with crystalline arrays were rich in ribosome and polysome with dilated mitochondria and many tiny vesicles. An individual virus particle was ca. 18 nm in diameter, and the center-to-center space ca. 22 nm. Crystalline arrays varied in size depending on the plane of section.

Animals↗
PubMed1980

Suppression of pokeweed mitogen-induced differentiation of human B cells by in vitro levamisole-treated T lymphocytes.

The generation of immunoglobulin-producing cells from human peripheral blood lymphocytes in pokeweed mitogen-simulated cultures was significantly suppressed by levamisole. Greatest suppression was observed when cells were incubated with levamisole at a concentration of 10(-6) M for 20 min or more prior to culture. Such suppression occurred when untreated as well as levamisole-treated B cells were co-cultured only with levamisole-treated T cells. Adding of levamisole-treated T cells to a combination of untreated autologous B and T cells resulted in the suppression of B cell differentiation. The results suggest that levamisole treatment of lymphocytes exerts suppression on pokeweed mitogen-induced B cell differentiation through its effect on T cell regulatory properties.

Adult↗