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Biomedical subjects

S Otani

Publications and source records attributed to S Otani.

At least 361 records · Page 20Linked to original sources
PubMed1979

Thymus-independent anti-DNP antibody responses to DNP-casein and DNP-gelatin.

Although studies on the molecular nature of thymus-independent antigens suggested that the polymeric structure with repeated antigenic determinants and slow metabolism are responsible for thymus-independence, we found that anti-DNP antibody responses to DNP-casein and DNP-gelatin were thymus-independent as well as macrophage-independent. These antibody responses were not affected by in vivo treatment with carrageenan or anti-thymocyte serum. In addition, responses of athymic nude mice to both antigens did not show any significant differences when compared with heterologous nu/+ mice. The findings were confirmed by in vitro experiments; non-adherent spleen cells or T cell-depleted spleen cells responded well to both antigens to the same extent as normal spleen cells. Since both casein and gelatin are polyclonal B cell activators and are not presumed to be high polymer or slow-metabolizing substances, we suggest that thymus-independence in many kinds of antibody response should be reconsidered.

Animals↗
PubMed1979

Anti-DNP antibody responses to DNP-histone H1 in mice.

Anti-DNP antibody responses to DNP-histone H1 in C3H/HeN mice were not suppressed by in vivo treatment with carrageenan in which many phagocytic macrophages were presumed to be impaired. Rather higher antibody responses to this antigen were observed in athymic nude mice than in heterozygous nude mice. Further, non-adherent spleen-cell and T-cell depleted spleen cells induced in vitro anti-DNP antibody responses to DNP-histone H1 to the same extent as normal spleen cells. These results suggest that anti-DNP antibody responses to DNP-histone H1 are macrophage- and thymus-independent. It was also observed that IgG-type anti-DNP antibodies to DNP-histone H1 were produced although most thymus-independent antigens were shown to induce predominantly IgM type antibodies but little, if any, IgG type antibodies. Furthermore, histone H1 did not show any polyclonal B-cell activator activities in contrast to many other thymus-independent antigens which act as polyclonal B-cell activators.

Animals↗
PubMed1978

Effect of urethan on the induction of ornithine decarboxylase in regenerating rat liver.

The effect of urethan on the induction of ornithine decarboxylase in the early stage of the regeneration of rat liver was studied. The induced activity of ornithine decarboxylase was suppressed by administration of urethan immediately after partial hepatectomy. Although ornithine decarboxylase was induced biphasically by partial hepatectomy, a single intraperitoneal injection of urethan resulted in the reduction of both phases. However, the ornithine decarboxylase activity induced by glucocorticoids and growth hormone was not suppressed by urethan. The increased level of 3',5'-cyclic adenosine monophosphate induced by partial hepatectomy was also reduced by urethan and this suppression was proportional to the suppression of ornithine decarboxylase activity. Reversal of the urethan-induced suppression of ornithine decarboxylase by administration of dibutyryl 3',5'-cyclic adenosine monophosphate was also observed.

Animals↗
PubMed1977

Suppression of phytohemagglutinin-induction of thymidine uptake in guinea pig lymphocytes by methylglyoxal bis(guanylhydrazone) treatment.

Treatment with methylglyoxal bis(guanylhydrazone), a specific inhibitor of S-adenosylmethionine decarboxylase (EC 4.1.1.50), suppressed the phytohemagglutinin-induction of [3H]thymidine uptake by guinea pig lymphocytes. The kinetics of [3H]thymidine uptake revealed that the Km value for thymidine was not changed, but the V value was markedly lowered by the methylglyoxal bis(guanylhydrazone) treatment. The induction of ATP: thymidine 5'-phosphotransferase (EC 2.7.1.75) (thymidine kinase) activity by phytohemagglutinin was suppressed to about the same extent as the induction of thymidine uptake. These suppressions were dependent on the methylglyoxal bis(guanylhydrazone) doses and on duration of the methylglyoxal bis(guanylhydrazone) treatment. Analysis of [3H]thymidine labelled compounds of the acid-soluble fraction showed that conversion of thymidine to thymidine 5'-triphosphate was inhibited by the methylglyoxal bis(guanylhydrazone) treatment. DNA polymerase activity was less inhibited by the methylglyoxal bis(guanylhydrazone) treatment in comparison with the methylglyoxal bis(guanylhydrazone) inhibition of thymidine uptake by whole cells. These results strongly suggested that blocking of polyamine accumulation by the methylglyoxal bis(guanylhydrazone) treatment influenced phytohemagglutinin induction of thymidine phosphorylation, resulting in a decrease of thymidine incorporation into DNA.

Cells, Cultured↗
PubMed1977

Elevated coronary venous oxygen content during oxygen breathing in the ischemic myocardium under pacing-induced stress in dogs.

The purpose of the present study was to investigate the effect of oxygen inhalation on the stressed (pacing-induced) ischemic myocardium. In 13 open-chest dogs, the left anterior descending coronary artery was partially occluded, the coronary vein accompanying the artery was cannulated for coronary venous blood sampling and a myocardial strain gauge arch was sutured on the myocardium perfused with the partially occluded coronary artery in order to measure the myocardial contractile force. The heart rate was increased by left atrial pacing to increase myocardial oxygen consumption. Respiration was instituted either with oxygen or with room air. Increase of the heart rate caused an increase of blood flow through the partially occluded coronary artery, an increase of the local myocardial oxygen consumption and no consistent change of the local myocardial contractile force both during air breathing and oxygen breathing, provided that the heart rate was less than 200. These values decreased if the heart rate was increased more than 200 both during air and oxygen breathings. Coronary venous oxygen content from the local coronary vein accompanying the partially occluded coronary artery was 2.7 ml per 100 ml on the average during air breathing, while it was elevated to 3.8 ml per 100 ml during oxygen breathing. Although, pacing caused a similar change on coronary blood flow or myocardial contractile force both during air and oxygen breathings, elevated coronary venous oxygen content during oxygen breathing might indicate that ischemic myocardium becomes more aerobic during oxygen breathing. This may be one of the reasons why patient with coronary artery disease can perform more work without complaining chest pain during oxygen breathing.

Animals↗
PubMed1977

Effects of carrageenan on immune responses. Studies on the macrophage dependency of various antigens after treatment with carrageenan.

Carrageenan, a sulfated polygalactose having macrophage toxic properties, elicited a marked suppression of IgM response to T cell-dependent antigens such as sheep red blood cells (SRBC), dinitrophenylated bovine serum gamma-globulin (DNP-BGG), and trinitrophenylated concanavalin A (TNP-Con A). In contrast, carrageenan did not inhibit antibody responses to such T cell-independent antigens as trinitrophenylated DEAE-dextran (TNP-DEAE-dextran), trinitrophenylated polyvinyl pyrrolidone(TNP-PVP), and trinitrophenylated Ficoll (TNP-Ficoll). Compared to total spleen cells, spleen cells from which macrophages had been removed by adhesion to plastic Petri dishes had less effect on the production of antibody against T cell-dependent antigens, but no change or a rather stimulated effect was observed in in vitro antibiody synthesis against T cell-independent antigens. These results strongly suggest that macrophages are involved in antibody responses to T cell-dependent antigens but not in those to T cell-independent antigens. However, the antibody response to trinitrophenylated lipopolysaccharide (TNP-LPS), a T cell-independent antigen, was inhibited by carrageenan treatment, suggesting that the response is macrophage dependent. Moreover, antibody response to higher doses of dinitrophenylated phytohemagglutinin (DNP-PHA), a T cell-dependent antigen, was shown to be macrophage independent by carrageenan treatment, although the antibody response to low doses of the antigen was macrophage dependent. Considering all these results, carrageenan treatment seems to be a very useful method to determine whether immune response to various antigens are macrophage dependent or not.

Animals↗