Biomedical subjects

Y Hirotsu

Publications and source records attributed to Y Hirotsu.

34 records · Page 2Linked to original sources

PubMed1983

The mediation of tissue eosinophilia in hypersensitivity reactions. III. Separation of two different delayed eosinophil chemotactic factors and transfer of these factors by serum or cells from sensitized guinea-pigs.

Two different eosinophil chemotactic factors (delayed ECF-a and ECF-b) were isolated from the delayed phase (24 hr old) of eosinophil-rich inflammatory reaction sites induced by DNP-ascaris extract, which could be separated by DEAE-Sephadex. Both the factors were thermolabile (56 degrees, 30 min) and had a mol. wt of about 70,000, whereas they were clearly different in antigenicity. Delayed tissue eosinophilia was shown to be mediated by peritoneal exudate cells (PEC) and serum from immunized donors to recipients. A chemotactic factor, closely resembling a delayed ECF-a, was isolated from the skin lesions of recipients transferred by sensitized PEC and challenged. Another factor, closely resembling a delayed ECF-b, was isolated from those of recipients transferred by immune serum and challenged. Furthermore, we have shown that delayed ECF-b, but not delayed ECF-a, shared a common antigenicity with some guinea-pig serum component. Thus we concluded that delayed tissue eosinophilia was mediated by the combined actions of two different factors, delayed ECF-a and ECF-b.

Animals↗

PubMed1983

The mediation of tissue eosinophilia in hypersensitivity reactions. IV. Production of delayed eosinophil chemotactic factor-a by peritoneal exudate cells from sensitized guinea-pigs in vitro.

An eosinophil chemotactic factor (ECF) was produced in the cell-free culture supernatants (CFS) of peritoneal exudate cells (PEC) from guinea-pigs immunized with dinitrophenyl derivatives of ascaris extract (DNP-As), when stimulated by the antigen in vitro without activation by immune complexes. A 2 or 6 hr pulse of the antigen was sufficient for ECF production, whereas long time incubation (48 hr) was required for the production of a sufficient amount of the factor. Treatment of PEC by cycloheximide resulted in the reduction of ECF production, suggesting that protein synthesis is essential. Its generation appeared carrier-specific and the source of the factor is presumed to be lymphocytes, probably T lymphocyte. The factor with a molecular weight of 70,000 shared a common antigenicity with delayed eosinophil chemotactic factor-a (delayed ECF-a), which was isolated from the skin lesions showing delayed tissue eosinophilia in vivo.

Animals↗

PubMed1983

The mediation of tissue eosinophilia in hypersensitivity reactions. V. Comparative study of tissue eosinophilia in the skin lesions of local and systemic passive cutaneous anaphylactic reactions.

Tissue eosinophilia in active cutaneous anaphylaxis reactions is biphasic: the early phase (6 hr) is induced by a low molecular (mol. wt. 300) factor (early ECF), and the delayed phase (24 hr) is mediated by synergy of two different factors (delayed ECF-a and -b). In this study, we report the mediation of tissue eosinophilia in passive cutaneous anaphylactic (PCA) reaction sites. Tissue eosinophilia in systemic PCA showed two phases with peaks at 6 hr and 24 hr, while that in local PCA was monophasic and peaked at 12 hr. A dialysable eosinophil chemotactic factor was isolated from the early stage (0-6 hr) of local PCA skin sites, and another chemotactic factor (mol. wt. 15,000), sharing a common antigenicity with guinea-pig serum C5, from 12-hr-old local PCA skin sites. On the other hand, a different chemotactic factor with a mol. wt. of about 70,000, sharing a common antigenicity with delayed ECF-b isolated from active cutaneous anaphylactic skin lesions, was isolated from 24-hr-old systemic PCA skin lesions. Although the dialysable factor was also isolated from systemic PCA skin sites, the factor from systemic PCA delayed skin sites may not contribute to delayed tissue eosinophilia, since the activity paralleled the intensity of basophil accumulation but not to that of eosinophils. It is thus suggested that tissue eosinophilia in systemic and local PCA reactions is mediated by different chemotactic factors.

Animals↗

PubMed1975

Synthesis and biological properties of the 2-L-beta-(pyrazolyl-1)alanine analogs of luteinizing hormone-releasing hormone and thyrotropin-releasing hormone.

The luteinizing hormone-releasing hormone (LH-RH) analog, less thanGlu-Pyr(1)Ala-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2, and the thyrotropin-releasing hormone (TRH) analog, less thanGlu-Pyr(1)Ala-Pro-NH2, were synthesized by azide couplings of the dipeptide hydrazide, less thanGlu-Pyr(1)Ala-NHNH2, to the C-terminal octapeptide of LH-RH and to proline amide, respectively. In an ovariectomized, steroid-blocked rat assay, the LH-RH analog was found to have only 1% of the LH-releasing activity of the natural hormone. The TRH analog was 1.5 times more effective than TRH itself in releasing TSH in vivo from the anterior pituitary of mice. This peptide is one of two synthetic peptides so far discovered which are more potent than TRH.

Alanine↗

PubMed1974