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Biomedical subjects

M Taguchi

Publications and source records attributed to M Taguchi.

At least 145 records · Page 8Linked to original sources
PubMed1987

Preparation and characterization of monoclonal antibodies against phosphoenolpyruvate carboxylase of Escherichia coli.

Twelve hybridoma clones which secrete monoclonal antibodies (mAb) against purified phosphoenolpyruvate carboxylase [EC 4.1.1.31] from Escherichia coli K-12 were obtained. These 12 mAb were prepared from the ascites fluids of mice. Six among the 12 mAb formed precipitin lines with the enzyme on immunodiffusion. Four mAb inhibited the activity of the enzyme and 2 mAb enhanced it. Four mAb altered the sensitivity of the enzyme to allosteric effectors. Competitive enzyme-binding experiments among the 12 different mAb were also performed. The results showed that the 12 mAb can be classified into at least 8 groups.

Allosteric Regulation↗
PubMed1986

Intracellular localization of human monocyte associated interleukin 1 (IL 1) activity and release of biologically active IL 1 from monocytes by trypsin and plasmin.

The production of interleukin (IL 1) by normal human peripheral blood monocytes purified by Ficoll-Hypaque density sedimentation, Percoll-gradient sedimentation, and plastic adherence can be detected as early as 30 min intracellularly, and extracellularly within 1 hr after stimulation with lipopolysaccharide (LPS). Production of mRNA coding for the isoelectric point 7.0 species of IL 1 was also detected as early as 1 hr after LPS stimulation and reached a maximum level at 6 hr. Cell-associated IL 1 activity could be extracted with CHAPS detergent from every cell fraction (i.e., membranes, cytosol, and particulates), but was present mainly (greater than 95%) in the cytosol of LPS-activated monocytes and the myelomonocytic cell line, THP-1. The apparent m.w. of IL 1 activity on high pressure liquid chromatography gel filtration in every cell fraction was approximately 23,000 daltons, with a minor peak at 31,000 daltons, whereas the IL 1 activity in the culture supernatants was 17,000 daltons. Western blotting analysis of LPS-stimulated monocyte extracts showed two forms of IL 1 corresponding to 31,000 daltons and 25,000 daltons. Exposure of viable cells to trypsin and plasmin released biologically active 23,000 dalton IL 1 only from IL 1-producing cells such as activated monocytes and IL 1-producing Ebstein-Barr virus B lymphocyte cell lines. Consequently, biologically active IL 1 is presumably exposed on the outer surface of cell membranes. Furthermore, IL 1 release by human monocytes in plasminogen-depleted fetal calf serum was considerably decreased. Conversely, supplementation of plasminogen-depleted serum with purified plasminogen restored the IL 1 production, suggesting that plasmin or plasmin-like factors may be involved in the regulation of the release of IL 1 from IL 1-producing cells. In conclusion, the results suggest that IL 1 is rapidly produced, is pooled in the cytosol, and in part is processed by enzymes, is transferred to the plasma membranes, and is then released from the cells. Tissue plasminogen activator and serum enzymes such as plasmin may therefore be involved in the release of IL 1 from IL 1-producing cells.

Body Fluids↗
PubMed1986

Direct phosphorylation of the IL-2 receptor Tac antigen epitope by protein kinase C.

Phorbol esters induce a rapid phosphorylation of the antigenic epitope of the human IL-2 receptor identified by anti-Tac monoclonal antibody. The physiological activator of protein kinase C, diacylglycerol also stimulated the phosphorylation of the Tac epitope in intact activated human T lymphocytes. Stable derivatives of cyclic nucleotides had no effect on the stimulation of Tac phosphorylation with cultured lymphocytes. Immunoprecipitated Tac derived from particulate membranes could serve as a direct substrate for purified protein kinase C in vitro. The Ca2+/phospholipid dependency of the in vitro phosphorylation reaction substantiated that the phosphorylation of Tac observed in intact cells stimulated by phorbol ester or diacylglycerol was the result of the physiological activation of protein kinase C.

Antigens, Surface↗
PubMed1985

[Mammography in diagnosis of breast cancer].

Radiographic features of 50 breast cancers were evaluated in comparison with 83 benign lesions and the diagnostic accuracy is discussed. Most of the usual primary and secondary findings of cancer such as spicula formation, microcalcifications, skin, thickening and nipple retraction were present in these 50 cancer lesions and all of them were recognized in the benign lesions as well, although less frequently. Because breast parenchyma was dense in 81% of the cases evaluated, and mostly due to moderate to severe dysplasia, the diagnosis of the breast lesions was difficult. Therefore, we must be cautious in calling a lesion benign. The radiographic detectability of cancer was 94%, and the diagnostic accuracy was 72%, which are comparable to the results reported from other places.

Adult↗
PubMed1985

The analgesic activity of D-Arg2-dermorphin and its N-terminal tetrapeptide analogs after subcutaneous administration in mice.

D-Arg2-dermorphin and its nineteen N-terminal tetrapeptide analogs were prepared, and their analgesic activities after subcutaneous administration in mice and the stability of a D-Arg2-dermorphin tetrapeptide to enzymatic degradation were examined. The analgesic effect was assessed by the tail pressure test. D-Arg2-dermorphin was found to have analgesic potency equal to or slightly greater than that of dermorphin. In a series of tetrapeptide analogs, a very pronounced activity greater than that of morphine was observed for analogs of the following structure, H-Tyr-D-Arg-Phe-X-OH (X = Gly, sarcosine and D-Ala) or its esters. Replacement of D-Arg2 by D-Arg(NO2), D-homoarginine or D-Lys resulted in a decrease in potency, suggesting that the guanidino group and side chain length of D-Arg2 are of great importance for a higher activity. D-Arg2-tetrapeptide (H-Tyr-D-Arg-Phe-Gly-OH) was found to be more stable than the parent tetrapeptide (H-Tyr-D-Ala-Phe-Gly-OH) to cleavage both by aminopeptidase M and by carboxypeptidase Y.

Analgesics, Opioid↗
PubMed1985

Immunoregulatory role in gamma interferon production by a T cell growth factor-dependent experimental malignant glioma-specific cytotoxic T lymphocyte clone.

The authors have established a murine malignant glioma-specific cytotoxic T lymphocyte clone (G-CTLL 1) by T cell growth factor (TCGF) using 203-glioma (a methylcholanthrene-induced ependymoblastoma of C57BL/6 mouse origin). The cloned cells were found to release a large amount of gamma interferon (IFN) in response to glioma-associated antigen-specific stimulation. The authors have investigated whether the IFN produced can contribute to killing the target cells. Adding anti-mouse gamma IFN antibody to the mixed clone-target cell culture inhibited IFN production by the cloned cells but the toxicity of the cells was minimally diminished. Therefore, it is suggested that the endogenous gamma IFN produced by the TCGF-dependent cloned cytotoxic T lymphocyte line does not have direct cytotoxic action on the target cells. Furthermore, IFN production as well as cytotoxicity was blocked by anti-Lyt-2 monoclonal antibody in the absence of complement. This suggests that IFN plays a role in the process of antigen recognition of target cells because the Lyt-2 molecule is involved in an antigen-specific function on the cytotoxic T lymphocyte receptor. The role of TCGF in gamma IFN production was also investigated. The spontaneous production of gamma IFN by the cloned cells paralleled the amounts of exogenous TCGF added to the cultures, but TCGF had no synergistic effect on IFN production in the presence of mitogen or tumor antigen. Accordingly, it is possible that TCGF stimulates the cloned cells to proliferate, causing IFN release.

Animals↗