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Biomedical subjects

M Kimoto

Publications and source records attributed to M Kimoto.

At least 217 records · Page 12Linked to original sources
PubMed1977

Regulation of antibody response in different immunoglobulin classes. II. Induction of in vitro IgE antibody response in murine spleen cells and demonstration of a possible involvement of distinct T-helper cells in IgE and IgG antibody responses.

In vitro induction of anti-DNP IgE as well as IgG1, IgG2a antibody responses was shown in murine spleen cell culture. Spleen cells primed three times with 1 mug of DNP-OA or DNP-Asc produced significant amounts of anti-DNP IgE as well as IgG antibodies by the in vitro stimulation with DNP-OA or DNP-Asc, respectively. Collaboration between DNP-primed B cells and carrier-primed T cells was required for the induction of both IgE and IgG antibodies with DNP-coupled T-dependent antigen. Carrier-specific T cells induced with a low dose of Asc (0.01 mug) showed helper function only on IgE antibody response, whereas T cells primed with a higher dose of Asc (10 mug) cooperated only with IgG-B cells. T cells primed with Asc in CFA showed helper function mainly on IgG antibody response but not on IgE antibody response. The result indicated the presence of a distinct population of T helper cells for IgE and IgG antibody responses. T-independent antigen (DNP-Ficoll) induced both anti-DNP IgE and IgG antibody responses in DNP-primed spleen cell population without the requirement of the collaboration of helper T cells.

Animals↗
PubMed1976

Antivitamin B-6 effect of 1-aminoproline on rats.

By intraperitoneal injection of 1-aminoproline, death after severe convulsion was observed in rats (LD50 of 1-amino-L-proline, 26 mg per kg of body weight for young male rats fed a normal diet). The vitamin B-6-deficient rats were more sensitive to this hydrazino acid than the normal rats. The toxic effect was completely prevented by the administration of pyridoxine. 1-Amino-D-proline was less toxic than the L-isomer. By the 1-aminoproline treatment, the most remarkable changes in the free amino acid levels were the striking increases in the concentrations of alpha-aminoadipic acid, citrulline and cystathionine in all the tissues tested, except in brain. Some unidentified ninhydrin-positive substances appeared. These results indicate that 1-aminoproline greatly disturbed the amino acid pattern, i.e. the amino acid metabolism in rats.

Amino Acids↗
PubMedDate not supplied

Gravity stress elevates the nociceptive threshold level with immunohistochemical changes in the rat brain.

Young Wistar male rats were exposed to 2G hypergravity by continuous centrifugation for 15 minutes. The nociceptive threshold was measured by using the von Frey type filament on the rat skin surfaces after hypergravity exposure. Following the hypergravity exposure, rats were sacrificed with anesthesia, then perfused and fixed for immunohistochemical examination. The 2G hypergravity elevated the nociceptive threshold up to 2-fold and induced analgesic effects on rats that remained for 2 hours after termination of centrifugation. Expression of Fos-immunoreactive proteins was prominently induced by 2G hypergravity in the arcuate nucleus and the paraventricular nucleus of the hypothalamus. The 15-minute flash exposure to 2G hypergravity induced pain suppression in rats, which might be attributed to change of neuronal activity in rat hypothalamus.

Animals↗
PubMedDate not supplied

Functional expression of a microinjected Ed alpha gene in C57BL/6 transgenic mice.

The class II major histocompatibility antigens, I-A and I-E, have been detected on the surface of certain immunocompetent cells, including B lymphocytes and monocytes. These molecules are involved in cell-cell interactions in the immune responses. Each class II antigen consists of two subunits, alpha and beta chains, and the genes encoding these subunits have been well characterized at the molecular level. To analyse the regulatory mechanism of E alpha gene expression and the role of the I-E antigen in the regulation of the immune responses, we have produced transgenic mice by microinjecting cloned Ed alpha genes into fertilized eggs of C57BL/6 mice of b haplotype. This strain of mouse carries a deletion in the upstream (5') region of the E alpha gene covering the transcriptional promoter and, therefore, does not express this gene. Interestingly, this genetic defect of the E alpha gene is accompanied by the inability of the host mouse to respond to a certain set of antigens, phenomena generally termed Ir gene control. We report here that the Ed alpha genes are expressed in these transgenic mice to form the I-Ed alpha Eb beta antigen on the surface of B lymphocytes and monocytes and that these I-E antigens are functional in terms of the induction of a mixed lymphocyte reaction and the restoration of immune responsiveness to poly(L-glutamic acid-L-lysine-L-phenylalanine) (GL-Phe).

Animals↗
PubMedDate not supplied

Forskolin-stimulated adenylylcyclase activity: a marker to assess islet cell viability following cold storage in different solutions and to predict islet cell function following transplantation.

For clinical islet cell transplantation, short-term storage of islet cells is likely to be necessary, and it is imperative that the islet cells be kept as viable as possible during the period. However, there are little data on which preservative solutions are most suitable for the storage of islet cells after isolations or before transplantation. To estimate islet cell viability and transplantation success rate in the present study, adenylylcyclase activity was measured with a rapid new fluorometric assay in rat islet cells prior to transplantation, because cAMP plays an essential role in determining islet beta-cell viability and responsiveness to various hormonal stimuli. Adenylylcyclase activity was measured in islet cells stored for different periods of time 0, 3, 16, 24, 48, 96 h) and in different preservative solutions. Approximately 1,000 islet cells from each preservation group using University of Wisconsin (UW) solution were transplanted to streptozotocin-induced diabetes mellitus (DM) rats. Transplant success was evaluated by measuring blood glucose levels. Preoperative adenylylcyclase activity was compared with posttransplant islet cell function. The adenylylcyclase activity of UW solution was significantly higher than that of Euro-Collins solution and lactate-Ringer's solution through the different preservation time periods. Preoperative adenylylcyclase activity correlated well with posttransplant islet cell function in a rat model of DM. We conclude that adenylylcyclase activity can be used as a marker to assess islet cell viability as well as differences in preservation media and may predict islet cell transplant success.

Adenylyl Cyclases↗