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Biomedical subjects

K Kikuchi

Publications and source records attributed to K Kikuchi.

At least 1,405 records · Page 78Linked to original sources
PubMed1976

Effect of the methyl methacrylate-tributylborane sealant in preventing occlusal caries.

A newly developed pit and fissure sealant, named Enamite, was studied technologically and clinically. Major ingredients of the sealant are a solution of 3% 2-hydroxy-3-beta-naphthoxypropyl methacrylate in methyl methacrylate and poly (methyl methacrylate) powder, using tributylborane as an initiator. In comparison with other commercially available sealants, Enamite showed much greater adhesiveness to enamel, which was confirmed by scanning electron micrographic observations. The sealant was applied to 161 first molars in 99 children, aged 6-8 years, to determine the caries preventive as well as the caries retardation effect. Among the treated teeth, 98 were intact and the remaining had incipient caries. The right side teeth of each subject was assigned to the test side and the other side served as a control. Each child was evaluated every 6 months by clinical exploration and bite-wing X-ray survey. At the final examination, the electric conductivity test was also used for the caries detection. After 2 years the sealant was effective in preventing 57.1% of the occlusal caries on treated compared with control teeth. When evaluation was made by including the caries retardation effect--teeth initially carious but remaining sealed after 2 years were counted as effective--, the sealant was effective in preventing or retarding 96.3% of the occlusal caries.

Adhesiveness↗
PubMed1976

Rat T lymphocyte-specific antigens and their cross-reactivity with mouse T cells.

Anti-rat T lymphocyte serum (ATLS)2 was prepared by immunizing rabbits with purified T cells from rat mesenteric nodes and absorbed with rat red cells and syngeneic sarcoma cells. The specificity of ATLS for rat T cells was confirmed by the following reasons: a) ATLS was not toxic for bone marrow cells but lysed most of the thymocytes and a number of spleen and lymph node cells, which were inversely correlated to the percentage of cells with B cell characteristics in respective organs; b) anatomical localization of ATLS-reactive cells in lymphoid organs coincided to the thymus-dependent areas, i.e. the paracortex of lymph node and the periarteriolar region of spleen; c) spleen cells treated with ATLS and complement failed to respond to phytohemagglutinin but normally responded to bacterial lipopolysaccharide; d) those cells treated with ATLS and complement could not induce a graft-vs-host reaction in F1 hosts, whereas the same treatment did not affect direct plaque-forming cells. All of these data confirm the specificity of ATLS and indicate that ATLS recognizes rat T lymphocyte-specific antigens (RTLA). Absorption studies showed that RTLA were present in higher concentration on medullary thymocytes and peripheral T cells than on cortical thymocytes, but absent from bone marrow, liver, and brain tissues. When the cross-reactivity of RTLA with mouse T cells was studied by C-dependent cytotoxicity and immunofluorescence, it was found that mouse T cells shared at least one determinant of RTLA with rat T cells, and that distribution pattern of the cross-reacting antigens in mouse lymphoid tissues was essentially the same as that of RTLA in rat lymphoid organs.

Absorption↗
PubMed1976

Inhibition of tumor growth in vivo and in vitro by macrophages from rats treated with a streptococcal preparation, OK-432.

The role of macrophages from rats treated with a streptococcal preparation (OK-432) for inhibition of syngeneic tumor growth was examined both in vivo and in vitro. Treatment of rats with OK-432 intraperitoneally resulted in a transient inhibition of ascites tumor growth and concomitant increase in survival time. Peritoneal exudate cells from these rats completely suppressed tumor growth when admixed with tumor cells and transferred subcutaneously to syngeneic recipient rats. No such effect was observed with tumor cells from saline-treated control rats. The macrophages were responsible for the neutralization of tumor growth, since the removal of adherent cells from peritoneal exudate cells of rats treated with OK-432 resulted in the abrogation of their antitumor activity. To further investigate the antitumor activity of macrophages, an in vitro cytotoxicity assay was carried out on several tumor cell lines. A complete target cell destruction was brought about by macrophages from the rats treated with OK-432 but not from the control animals. The tumor cytotoxicity mediated by macrophages activated with OK-432 was regarded as non-specific because they could damage all the target cell lines tested.

Animals↗
PubMed1975

Studies on etiology of essential hypertension. Hemodynamics, water-sodium balance and response to pressor substances during long-term sodium restriction and after spontaneous blood pressure fall--.

CI, TPRI, PV, ECFV, Nae, PRA and a pressor response to NA and AT was measured before and after 1) sodium restriction and 2) spontaneous blood pressure fall (spontaneous fall) in the patients with essential hypertension and the following results were obtained. 1) CI did not change during sodium restriction and increased after spontaneous fall. TPRI was reduced and the degree of this reduction was positively correlated with that of blood pressure reduction under these two conditions. 2) Sodium restriction caused the decrease of PV, ECFV and Nae and the increase of PRA. The degree of the reduction of PV and Nae was positively correlated with that of blood pressure fall. After spontaneous fall, PV, ECFV and NAe was increased and PRA did not change significantly. 3) A pressor response to NA and AT was depressed after one week of sodium restriction, and after 4 weeks the former returned to the basal response, while the latter was still reduced. NA response was correlated positively with basal Nae, ECFV and interstitielle fluid volume and negatively with basal PRA. AT response was negatively correlated with PRA before and during sodium restriction. No correlation was observed, however, between the degree of reduction of blood pressure and that of the change in pressor response to NA or AT. After spontaneous fall, the response to NA was not reduced but increased. These results suggested that, although the fall in blood pressure under these experimental conditions was mediated by the reduction of TPRI, the changes in pressor response to NA and AT did not affect primarily the reduction of blood pressure.

Angiotensin II↗
PubMed1975

Surface antigenic specificities of human thymus-derived lymphocytes.

Surface antigenic specificities of human thymus-derived (T) lymphocytes were studied by cytotoxicity tests using a heterologous rabbit anti-human thymus serum. This serum showed higher cytotoxic titres on thymocytes by comparison with peripheral lymphocytes. After proper absorption the antiserum was non-toxic for chronic lymphatic leukaemia cells, but lysed the majority of thymocytes. It also lysed some of peripheral lymphocytes, corresponding to those lymphocytes which bound sheep erythrocytes (E) but not erythrocyte-antibody-complement complexes (EAC). Pretreatment of lymphocytes with the absorbed antiserum and complement completely abrogated rosette formation with E but spared EAC-binding lymphocytes. It also eliminated their reactivity to phytohaemagglutinin and concanavalin A. These findings indicate that the absorbed serum causes selective lysis of T cells. The results obtained from quantitative absorption studies suggest that a certain loss of T-cell antigens is brought about during the differentiation of thymocytes into peripheral T cells.

Animals↗