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Biomedical subjects

S Tamura

Publications and source records attributed to S Tamura.

At least 721 records · Page 40Linked to original sources
PubMed1984

[Shift of placental alkaline phosphatase isoenzymes in the course of pregnancy].

It is generally accepted that every placental protein shows its characteristics vicissitude pattern during pregnancy and that alkaline phosphatases (ALP) are subdivided into three kinds of isoenzymes, i.e.: tissue-unspecific, intestinal and termplacental ALPs. In this study, the changes in ALP isoenzyme profile throughout the course of pregnancy was studied by biochemistry, enzyme- and immuno-histochemistry, and the following results were obtained. In early pregnancy, ALP activity was composed mostly of tissue-unspecific ALP isoenzyme, and its activity revealed a peak value around 10 weeks of pregnancy as in the case of the hCG serum concentration. At the end of the second trimester of pregnancy, instead of tissue-unspecific isoenzyme, ALP activity was mainly composed of term placental ALP isoenzyme, but a very small amount of the isoenzyme was proved to exist in the villi at the 6th week of gestation. The above results were confirmed by morphological studies such as enzyme-cytochemistry and immuno-cytochemistry. It was therefore concluded that at least two genes of ALP isoenzymes existed in the villi and that the regulation of gene activity changed during the course of pregnancy. Furthermore, since tissue-unspecific ALP isoenzyme showed a pattern of change similar to that of serum hCG, the existence of a developmental phase-specific gene set was postulated.

Alkaline Phosphatase↗
PubMed1984

[Re-evaluation of the carrageenin-induced abscess model as a screening method for anti-inflammatory agents].

For the simple assay of anti-inflammatory agents and the analysis of their mode of action, the early inflammatory reactions of the carrageenin abscess model in rats were studied by determining abscess (exudate) weight, vascular permeability measured by extravascular dye leakage, protein, prostaglandins (PGs), and DNA (an index of leucocyte infiltration). Subcutaneous injection of 0.5 ml of 2% carrageenin in the dorsal sacral region of rats induced an edema with an initial weak phase (3 hr) followed by a second pronounced phase, reaching a maximum (2.3 g) at 15 hr and declining steadily thereafter. During the first 15 hr, there was a good correlation between the edema formation and changes in the increased vascular permeability, and also the PGE contents in the exudate paralleled the permeability, but thereafter, these components did not follow the same time course. The marked increase in DNA content in the exudate started after a lag time of a few hr in correspondence with the second accelerated edema formation. The edema formation was effectively inhibited by indomethacin and dexamethasone given simultaneously with the irritant injection; maximum inhibition with indomethacin (2 mg/kg, p.o.) was 36% at 15 hr and 48% with dexamethasone (0.1 mg/kg, p.o.) at 9 hr. Indomethacin very significantly affected exudate PGE levels and vascular permeability, rather than suppressing the edema formation. When the treatment was initiated at 9 hr after injury, it was not effective in reducing the weight of the 24-hr abscess, whereas it had significant effect on the PGE concentration. Dexamethasone did not exert significant effect on the PGE levels despite its potent and steady anti-edematous activities.(ABSTRACT TRUNCATED AT 250 WORDS)

Abscess↗
PubMed1983

Insulin-like effect of trypsin on the phosphorylation of rat adipocyte insulin receptor.

Trypsin treatment of a partially purified insulin receptor preparation from rat adipocytes stimulated the phosphorylation of 90,000- and 72,000-Da polypeptides immunoprecipitated by anti-insulin receptor antibody. The phosphorylation of tyrosine residues alone was observed in both polypeptides. Trypsin concentrations which stimulated insulin receptor phosphorylation were the same as those previously shown to activate rat adipocyte glycogen synthase. Trypsin treatment of the insulin receptor fraction also stimulated the phosphorylation of an exogenous substrate of tyrosine kinase similarly to insulin treatment. Trypsin treatment of a highly purified insulin receptor from human placenta also activated the phosphorylation of the receptor-derived peptides. These results suggest that the insulin-stimulated protein kinase, a component of the insulin receptor, was activated by tryptic digestion to phosphorylate polypeptides derived from the insulin receptor itself. Thus, it is suggested that stimulation by trypsin of phosphorylation of the insulin receptor may be related to the insulin-like metabolic actions of trypsin observed in rat adipocytes.

Adipose Tissue↗
PubMed1983

Effects of pertussis toxin on delayed-type hypersensitivity responses and on the activity of suppressor T cells on the responses.

Experiments were performed on mice to investigate the effects of pertussis toxin (PT) on delayed-type hypersensitivity (DTH) to ovalbumin (OA) and on the activity of suppressor T cells on the DTH (DTH-Ts). Mice immunized with alum-precipitated ovalbumin showed a transient DTH, which was determined as footpad swelling which disappeared 2 weeks after immunization. Maximal footpad swelling was observed 24 hr after DTH elicitation. On the other hand, when mice received PT (2 micrograms/mouse) at the time of immunization, the transient DTH became an enhanced and persistent DTH, which persisted for at least 4 weeks. In addition, the time of maximum footpad swelling was delayed from 24 to 48 hr after DTH elicitation. The immune spleen T cells from PT-treated mice showed a persistently high ability to transfer DTH into syngenic naive mice. DTH-Ts was induced in spleens of mice injected iv with OA-coupled syngeneic spleen cells. However, when these mice received PT at the time of suppressor induction, their spleen cells revealed considerably reduced suppressor activity. The activity of DTH-Ts was also reduced when DTH-Ts were either treated in vitro with PT or transferred into PT-injected recipient mice. From these results, interference with the suppressor function of DTH-Ts from PT was considered to be, at least in part, as an enhancing mechanism of DTH.

Animals↗
PubMed1983

Insulin-like effect of vanadate on adipocyte glycogen synthase and on phosphorylation of 95,000 dalton subunit of insulin receptor.

Vanadate enhanced the state of activation of rat adipocyte glycogen synthase in a manner similar to that of insulin. No additional effect was observed when insulin and vanadate were added together. The effect of vanadate, like insulin, was reversed by incubation with epinephrine. Vanadate also enhanced the degree of phosphorylation of the 95,000 dalton subunit of insulin receptor, selectively on tyrosine residues, in the solubilized rat adipocyte insulin receptor system. This demonstrates that insulin and vanadate have similar initial actions on receptor phosphorylation and also act similarly on an intracellular event, namely the activation of glycogen synthase.

Adipose Tissue↗
PubMed1983

Hypertriacylglycerolemia and adipose tissue lipoprotein lipase activity in the Nagase analbuminemic rat.

In Nagase analbuminemic rats, serum triacylglycerol levels were significantly elevated. This abnormality was accompanied by decreased adipose tissue fat stores, and both were more marked in female than in male rats. Parametrial adipose tissue lipoprotein lipase activity was determined in normally fed female rats. When expressed per mg protein, the activity in analbuminemic rats was only 35% of that in control rats. The activity in analbuminemic rats, however, could be increased as in control rats by refeeding starved animals with a fat-free and carbohydrate-rich diet, and the peak values recorded were the same with the two groups. Treatment of animals with streptozotocin lowered adipose tissue lipoprotein lipase activity in both groups to similar levels. These results suggest that hypertriacylglycerolemia associated with analbuminemia may be caused, at least in part, by altered hormonal control of adipose tissue lipoprotein lipase activity.

Adipose Tissue↗
PubMed1983

Stimulation of maximal intracellular insulin action on glycogen synthase by preincubation of adipocytes with adenosine 5'-triphosphate.

Preincubation of rat adipocytes with ATP further stimulated maximal insulin action on glycogen synthase. Half-maximum concentration of ATP was 5 X 10(-5) M. ATP, ADP, adenosine, inosine, and GTP were effective, while beta-gamma-methylene ATP was without effect. ADP and GTP were less potent than ATP, adenosine, or inosine. Inosine was active without insulin but was without effect in the presence of insulin. The mechanism of action of adenosine was clearly different from ATP. While ATP required both Mg2+ and Ca2+ for effectiveness, adenosine required only Ca2+. The effect of ATP, but not of adenosine, was preserved after cells were washed. The adenosine effect was completely blocked by theophylline, but the ATP effect was inhibited only 40%. The ATP effect was thus not due to adenosine generated by ATP breakdown.

Adenosine↗
PubMed1983

Management of massive hemobilia with angiographic embolization.

Two cases of angiographic embolization for the management of massive hemobilia due to hepatico-jejunostomy and percutaneous transhepatic biliary drainage are presented. The clinical features are described together with a short review of the literature. In addition to defining the bleeding source, angiography provides an effective and safe alternative to surgery for the control of hemobilia.

Aged↗