Search PubMed⌕ Search

Biomedical subjects

K Kikuchi

Publications and source records attributed to K Kikuchi.

At least 1,387 records · Page 77Linked to original sources
PubMed1977

Effects of a 2-substituted adenosine derivative, 2-(p-methoxyphenyl)-adenosine (CV-1674) on coronary and cardiohemodynamics, and myocardial energetics.

In dogs, intracoronary doses of CV-1674, adenosine ( ADS) and 2-Cl-ADS for doubling coronary flow were estimated as 5.0, 2.0 and 0.4 microgram/dog, and i.v. doses 31, 71 and 2.5 microgram/kg, respectively. ADS and 2-Cl-ADS decreased, while CV-1674 increased LV dp/dt. Intravenous infusion (30 min) of CV-1674 (10 microgram/kg per min) and ADS (700 microgram/kg per min) decreased coronary resistance to approximately the same extent. Decreases in blood pressure, total peripheral resistance and myocardial O2 concumption with ADS were more prominent than those with CV-1674. ADS produced a marked bradycardia that was not evident with CV-1674. Neither agent had a significant influence on myocardial efficiency. In guinea pig atria, ADS and 2-Cl-ADS exerted negative effects while those with CV-1674 were positive inotropic and chronotropic. In cats, intraduodenal ADS (10 mg/kg) produced no effects on cardiohemodynamic parameters. CV-1674 (250 and 500 microgram/kg) increased myocardial tissue blood flow (MBF) with a slight hypotension in a dose-dependent manner, whereas 2-Cl-ADS (100, 250 and 500 microgram/kg) increased MBF only with the highest dose concomitantly with marked hypotension and bradycardia. These results suggest that CV-1674 induces selective coronary vasodilation with less depression on cardiohemodynamics, and is relatively well absorbed from the intestinal tract. The pharmacological profile of the compound, therefore, differs from that of ADS and 2-Cl-ADS.

Adenosine↗
PubMed1977

A simple method of cell-mediated cytotoxic assay by postlabeling of tritiated thymidine.

The cytotoxic reaction of effector cells on target cells was performed on cover slips which were set in a petri dish so as to be interposed from the dish surface through the bases of the slide glasses. After incubation, the target cells remaining on the cover slips were pulse-labeled with 3H-TdR for 45 min. Subsequently, the cover slips were removed from the bases, and dipped in cold 5% TCA to be freed from non-incorporated isotopes. The residual target cells adhering on the cover slips were counted without being removed. By this assay system, the specific or non-specific cytotoxicity of lymphocytes or macrophages was easily demonstrated with reliability.

Animals↗
PubMed1977

Inhibition of cellular DNA synthesis by rat peritoneal macrophages.

The DNA synthesis in syngeneic, allogeneic and xenogeneic cells was inhibited by peritoneal macrophages of normal WKA rats. This inhibitory effect of macrophages was found to be mediated by a soluble factor (MfID) released into a culture medium from macrophages which was heat-stable and non-dialyzable. The MfID was also responsible for the inhibtion of lymphocyte DNA synthesis by MLC reaction. The action of MfID was indicated to suppress rather than to kill cell growth. It was interpreted that the inhibitory effect of macrophages on cellular DNA synthesis is their inherent property and macrophages may play the role of regulating the proliferation of lymphocytes and other cells.

Animals↗
PubMed1977

Identification of human peripheral T cell antigens.

A new type of differentiation antigens on human T cells was demonstrated by using a heterologous anti-human T cell serum (ATS). This type of antigen, referred to as human peripheral T cell antigen (HPTA), was found on peripheral T cells and medullary thymocytes, but not on cortical thymocytes and B cells. The percentage of ATS-reactive lymphocytes in human peripheral lymphoid organs was correlated with that of cells rosetting with sheep erythrocytes, but contrasted with the number of B cells defined by the presence of a complement (C) receptor or by rabbit anti-human B cell serum (ABS). ATS also reacted with T cells purified by nylon fiber column filtration but ABS did not. Chronic lymphocytic leukemia cells rosetted with either sheep erythrocytes or erythrocyte-antibody-complement complexes were lysed by ATS and ABS, respectively. Mitogenic responses of blood lymphocytes to phytohemagglutinin (PHA) and concanavalin-A (Con A) were abrogated by treating them with ATS and C, whereas ABS suppressed only their response to Con A. Although numerous thymus cells rosetted with SRBC, only 14% were reactive with ATS. Quantitative absorption studies demonstrated that HPTA content of the thymus cells was much lower than that of lymph node cells. Anatomical localization of ATS-reactive lymphocytes in human lymphoid organs studied by immunofluorescence indicated that they were present in the thymus-dependent paracortical areas of lymph node and in the medullary region of thymus. ABS, on the other hand, did not stain thymocytes but reacted selectively with the cells located in the lymphoid follicles of lymph node. These data, together with that from cell suspension studies, confirmed that HPTA were shared between medullary thymocytes and peripheral T cells.

Antigens↗