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Biomedical subjects

Y Ishida

Publications and source records attributed to Y Ishida.

At least 667 records · Page 37Linked to original sources
PubMed1983

Mechanism of inhibition of contraction by cadmium in guinea-pig taenia coli.

Further evidence about the mechanism of the inhibition of contractions caused by cadmium ions (Cd2+) in guinea-pig taenia coli has been sought. Cd2+ at a concentration of 0.5 mM completely inhibited the high-K (40 mM)-induced contraction within 3-5 min. Cd2+ did not shift the Ca2+-induced concentration-response curve to the right in Ca2+-free K+ depolarized muscle, although it reduced the Ca2+ response size. The K+-induced increase in tissue calcium content and 45Ca uptake determined by the lanthanum method was significantly reduced in the presence of Cd2+ (0.5 mM) and the contractions of the glycerolated taenia coli were inhibited with increasing Cd2+ (0.001-0.5 mM). Muscle strips, incubated in a medium containing 0.5 mM Cd2+, accumulated greater amounts of cadmium than within the extracellular space. It is suggested that the inhibitory action on tension produced by Cd2+ in taenia coli may result from the interference of calcium permeability at the cell membrane. There is the possibility that Cd2+ acts on the contractile system of the muscle.

Animals↗
PubMed1983

Activation of tubuloglomerular feedback in rat nephrons by sera from rabbits with fulminant hepatic failure.

Experiments were designed to determine whether substance(s) other than electrolytes might activate tubuloglomerular feedback in experimental fulminant hepatic failure. Severe hepatic damage and renal dysfunction were induced by intravenous administration of D-galactosamine. Sera from normal or D-galactosamine-treated rabbits were dialyzed against glucose solution to reduce electrolyte concentrations. Tubuloglomerular feedback response was evaluated in rat nephrons by measuring the early proximal flow rate (EPFR) during orthograde perfusion of the loop of Henle. EPFR was reduced by 28 and 48% with Ringer's solution and sera from D-galactosamine-treated rabbits, respectively, but was not altered by normal sera. Substance(s) other than electrolytes in the sera from D-galactosamine-treated rabbits might activate the tubuloglomerular feedback to reduce glomerular filtration.

Animals↗
PubMed1983

Alpha-adrenolytic and anti-serotonin activities of apogalanthamine analogs on the rat aortic strips.

Most of apogalanthamine analogs were more specific in alpha-adrenolytic activity than in anti-serotonin activity. In this report, 1,2,11-trimethoxy-N-methyl-5,6,7,8-tetrahydrodibenz[c,e]azocine(abbreviated as K-35) was found to be stronger in activity against serotonin (pA2 = 7.11 +/- 0.08) than against adrenaline (pA2 = 6.24 +/- 0.06). Apogalanthamine analogs have a tetrahydrodibenz[c,e]azocine structure, in which one benzene can be regarded as a part of benzylamine and other as a part of phenethylamine. From the pharmacological point of view, various azocine compounds were tested, the phenethylamine in the azocine structure is demonstrated to contribute toward the alpha-adrenolytic activity and the benzylamine having two methoxy groups contributes toward the anti-serotonin activity.

Adrenergic alpha-Antagonists↗
PubMed1983

[Atypical meningioma with xanthogranulomatous stromal reaction].

A case of atypical meningioma with xanthogranulomatous stromal reaction was described in a 37 year-old man. At the age of 18, the patient started to have seizures. He became aware of disturbances in gait since 27 years of age. At the age of 37 he came to the hospital for detailed examinations and adequate treatment. EEG showed focal spikes at right temporal area and the CT scan disclosed abnormalities indicating the presence of a right posterior temporal mass. At craniotomy, a tumor was found located over the surface of right temporal lobe. It was well-circumscribed, firm in consistency and was attached to the dura, measuring 3cm in its greatest diameter. Gross total removal was accomplished. On cut section, the tumor was greyish in color mottled variously with yellow or rustbrown tint. It contained a cyst. Microscopically, the tumor was made up of compact masses of spindle-shaped or polygonal cells. The cells were arranged in areas in interlacing fascicles or forming whorles. In many places the tumor showed pleomorphic cytology. Mitotic figures were found few in number. The cytoplasm of the neoplastic cells appeared groundglass-like. Some of them contained hyaline globules. The globules were found to react positive with P.A.S. technique, and this procedure was resistant against diastase digestion. They were also stained positive with P.T.A.H. stain. In some areas foamy xanthomatous cells were found in groups. A large number of lymphocytes, plasma cells, eosinophiles and macrophages ingesting brownish pigments were found infiltrating around vascular vessels.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Anoxia-induced contraction of guinea-pig taenia coli in a glucose-free medium.

The smooth muscle of guinea-pig taenia coli contracted upon exposure to an oxygen deprived glucose-free medium aerated with 95% N2 and 5% CO2. An aeration using 95% O2 and 5% CO2 resulted in an immediate relaxation of the contraction. The anoxia-induced muscle contractions were diminished when the preparations were pretreated with the Ca antagonist D-600. However, the anoxia-induced contractions were not affected by posttreatment with D-600. The 45Ca uptake using the lanthanum method was enhanced at the onset of the anoxia-induced contractions in a glucose-free medium. However, the 45Ca uptake was comparable to control levels in the late phase of anoxia-induced muscle contractions. These results suggest that Ca permeability of cell membranes increases with the onset of an anoxia-induced muscle contraction in glucose-free media.

Animals↗
PubMed1983

[Investigation of tin and chromium grain boundary diffusion in iron by microautoradiography].

Microautoradiography using conversion electron and Auger electron of the isotopes 119mSn and 51Cr which were diffused from the surface in pure iron was investigated. The surface layers were removed successively by chemical reagents to prepare the specimen for microautoradiographs. The density of silver particles was measured in the boundary region and was normalized by comparing with the density near the triple point of the grain boundary. Differences of the diffusion coefficients in the grain boundary were investigated from the frequency diagram of the isotope concentrations near the boundary in individual specimens.

Autoradiography↗
PubMed1982

The inhibitory effect of monensin on high K-induced contraction in guinea-pig taenia coli.

This study deals with the effects of monensin, a Na ionophore, on contraction, cellular Na content, oxygen consumption and tissue ATP content of smooth muscle of the guinea-pig taenia coli depolarized by high K (62.7 mM) solution. The application of monensin (10(-8) -10(-6) M) had little effect on the phasic component of the K contraction while it decreased the tonic component. The inhibitory effect of monensin, unlike that of verapamil, was not antagonized by raising the concentration of external Ca. Under hypoxic conditions, the inhibitory action of monensin (10(-7) M) was greatly reduced. The removal of Na (choline or sucrose substitution) from the high K solution did not attenuate the inhibitory effect of hypoxia or monensin. Monensin (10(-7) M) produced only a small increase in cellular Na in the depolarized muscle. The K-induced increase in the rate of oxygen consumption was suppressed by monensin (10(-6) M). In high K solution, but not in normal solution, monensin (10(-6) M) decreased the tissue ATP content. These results suggest that the relaxing action of monensin is mainly due to the inhibition of aerobic energy metabolism of the smooth muscle of guinea-pig taenia coli.

Adenosine Triphosphate↗
PubMed1982

Imidazole-induced potentiation of the contractile response to various agonists in vascular smooth muscle.

In isolated rabbit aortae, imidazole (10(-4)M) caused a unique nonspecific potentiation of the contractile responses to prostaglandins, norepinephrine, 5-hydroxytryptamine, histamine and potassium only at low concentrations. Imidazole had no effect on the dose-response relationship for Ca2+ in the presence of potassium, 40 mM. Imidazole potentiated contractions in supersensitive strips pretreated with reserpine or with low temperature (5 degrees C) for 5 days. In the presence of theophylline (3 x 10(-4)M), imidazole failed to potentiate the responses to norepinephrine, 5-hydroxy-tryptamine, histamine and potassium, but significantly potentiated responses to prostaglandin E1, E2 and F2 alpha. Imidazole (10(-4)M) significantly decreased the 45Ca uptake of aorta in a Ca-free solution, whereas the drug did not affect 45Ca uptake in a normal solution. These results suggest that imidazole-induced potentiation is related to an increase in Ca2+ permeability and possibly to an additive effect on Ca2+ binding.

Animals↗
PubMed1982

Assay of free and glycine- and taurine-conjugated bile acids in serum by high-pressure liquid chromatography by using post-column reaction after group separation.

An accurate and sensitive method that involves the group separations of serum bile acids (i.e. free and glycine- and taurine-conjugated bile acid fractions) by ion-exchange chromatography on piperidinohydroxypropyl-Sephadex LH-20 is described. Each group was then analysed by high-pressure liquid chromatography by using the post-column reaction technique with immobilized 3 alpha-hydroxy steroid dehydrogenase. The bile acid patterns in the umbilical venous serum samples were analysed by this method. Taurochenodeoxycholate predominated in the umbilical blood.

3-Hydroxysteroid Dehydrogenases↗