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Biomedical subjects

Y Ishida

Publications and source records attributed to Y Ishida.

At least 649 records · Page 36Linked to original sources
PubMed1984

[The analysis of left ventricular filling dynamics by radionuclide ventriculography using ECG's R wave and the second heart sound gating techniques].

To assess the impairment of early diastolic left ventricular (LV) filling and the effect of atrial contraction on total LV filling in patients (pts) with coronary artery disease (CAD), LV volume (LVV) changes during rapid filling (RF) and atrial contraction (AC) phases were studied by equilibrium radionuclide ventriculography in 10 normals (N) and 17 pts with CAD including eight without (CAD-1) and nine with (CAD-2) previous myocardial infarction (MI). The data were acquired in a list-mode fashion as a series of X, Y coordinates, time markers and an ECG's R wave (R) plus the second heart sound (S2) markers. LVV curves were obtained from three types of multi-gated images by (1) R-synchronized forward reformatting for the analysis of systolic phase (ejection fraction; EF and peak ejection rate; PER), (2) S2-synchronized forward reformatting for the analysis of RF phase (peak filling rate; PFR-RF and filling fraction; FF) and (3) R-synchronized backward reformatting for the analysis of AC phase (peak filling rate; PFR-AC and LVV increment with atrial contraction/stroke volume; AC/SV). EF and PER were significantly lower (p less than 0.001) in CAD-2 (36.0 +/- 8.1% and -1.5 +/- 0.4 EDV/sec) than in N (58.2 +/- 5.8% and -2.4 +/- 0.4 EDV/sec), but those in CAD-1 (52.7 +/- 6.4% and -2.2 +/- 0.3 EDV/sec) were almost the same as N. However PFR-RF and FF were reduced both in CAD-1 (1.5 +/- 0.4 EDV/sec and 23.0 +/- 7.0%) and CAD-2 (1.3 +/- 0.4 EDV/sec and 19.0 +/- 8.0%) compared with N (2.3 +/- 0.4 EDV/sec and 37.0 +/- 8.3%). PFR-AC and AC/SV were significantly greater (p less than 0.01) in CAD-1 (1.3 +/- 0.3 EDV/sec and 0.30 +/- 0.06) than N (0.8 +/- 0.3 EDV/sec and 0.13 +/- 0.07), but those in CAD-2 (0.6 +/- 0.4 EDV/sec and 0.18 +/- 0.09) showed no increase like in CAD-1. These results indicate that 1) the impairment of early diastolic filling precedes the evidence of systolic dysfunction in pts with CAD and 2) AC could compensate the impaired early filling in pts without prior MI, whereas in pts with prior MI this compensatory mechanism is absent presumably because of elevated LV filling pressure.

Adult↗
PubMed1984

Effects of 3,4-dihydro-6-[4-(3,4-dimethoxybenzoyl)-1-piperazinyl] -2(1H)-quinolinone (OPC-8212), a new inotropic agent, on cardiotonic activity and coronary hemodynamics.

Cardiotonic activity and chronotropic effect of a new positive inotropic agent, 3,4-dihydro-6-[4-(3,4- dimethoxybenzoyl )-1-piperazinyl]-2(1H)- qu inolinone ( OPC -8212), were studied in isolated canine hearts eliminating the secondary effect due to neurohumoral alterations. Positive inotropic action of OPC -8212 was dose-dependent and its potency was equivalent to about 1/10(5) of isoprenaline (isoproterenol). However, the duration of action was two to three times longer than that of isoprenaline, and arrhythmogenic activity was not observed at any dose studied. An index of inotropic state, Emax, was increased by this agent even under the blockade of beta-adrenoceptors, indicating that the positive inotropic effect of this agent is not due to a stimulation of beta-adrenoceptors. the ventricular relaxation rate was enhanced dose-dependently in similar extent to the equivalent dose of isoprenaline. Effects of this agent on coronary blood flow (CBF) and myocardial oxygen consumption (MVO2) were also assessed in open chest dogs, eliminating secondary increases in these parameters due to an increase in mechanical load or heart rate. OPC -8212 increased MVO2 significantly even without significant alterations in heart rate and LV pressure. These increases both in CBF and MVO2 were similar to those of isoprenaline while arterio-venous difference in oxygen content was not affected by OPC -8212. Thus, we conclude that the efficiency of myocardial oxygenation of OPC -8212 is similar to that of isoprenaline and a direct coronary vasodilatory effect of this agent is minimal.

Animals↗
PubMed1984

[A clinical study on cefoperazone in serious infections associated with hematological malignancy].

Clinical and bacteriological efficiencies of cefoperazone (CPZ) in 19 serious infections associated with hematological malignancy were studied. CPZ was clinically effective in 13 cases (68.4%). Excellent effects were obtained in 3 cases (15.8%), good effects in 7 cases (36.8%) and fairly good effects in 3 cases (15.8%). The rate of clinical effectiveness by CPZ was not dependent on neutrophils number in peripheral blood. Bacteriological effectiveness to isolated organisms in 15 cases was obtained in 9 cases (60%). Clinically significant serum concentrations of CPZ persisted over 6 hours after injection (1 g/l hour, d.i.v.). In comparative study of MIC against clinically isolated P. aeruginosa, CPZ was superior to other cephalosporins. Adverse reactions were not significant except for 3 cases with abnormalities of hepatic function.

Adult↗
PubMed1983

Palytoxin isolated from marine coelenterates. The inhibitory action on (Na,K)-ATPase.

Palytoxin (PTX), C129H223N3O54, a highly toxic substance isolated from zoanthids of Palythoa tuberculosa, inhibited (Na,K)-ATPase (ATP phosphohydrolase, EC 3.6.1.3) prepared from guinea pig heart and hog cerebral cortex in a dose-dependent manner at concentrations greater than 10(-8) M. In the presence of Na (100 mM) and K (20 mM), PTX showed potency nearly equal to that of ouabain. When the ATPase was activated by the various Na concentrations at a constant K concentration, both PTX and ouabain inhibited the ATPase activity noncompetitively. On the other hand, when K concentration was changed at a constant Na concentration, PTX caused a competitive inhibition in all ranges of K concentrations employed, whereas ouabain caused a competitive inhibition at low concentrations and a noncompetitive inhibition at high concentrations.

Acrylamides↗
PubMed1983

Enhancing effect of H-2-linked NZW gene(s) on the autoimmune traits of (NZB X NZW)F1 mice.

To investigate the possible enhancing effect of the H-2z haplotype of the New Zealand White (NZW) strain on the production of autoantibodies and renal disease observed in B/W F1 mice, we developed the ZWD/8 strain, a NZW congenic line carrying the H-2d haplotype, produced (NZB X ZWD/8)F1 (B/WD8 F1) mice, and examined the difference in several immunological abnormalities between the B/W F1 (H-2d/H-2z) and the B/WD8 F1 (H-2d/H-2d) mice. In comparison with B/W F1 mice, the B/WD8 F1 mice showed markedly lower serum levels of the anti-DNA antibodies and the gp70 ICs, and a later onset and a lower incidence of proteinuria with a lower mortality. In contrast, there was no significant difference in the incidences and the amounts of both natural thymocytotoxic autoantibody and anti-erythrocyte autoantibody between these two hybrid strains. Further, the serum levels of IgG and IgM in B/WD8 F1 mice were as high as those in B/W F1 mice. These findings indicate that the gene(s) that is within or closely linked to the H-2 complex of NZW strain specifically acts to intensify the levels of anti-DNA antibodies and gp70 ICs, and to promote the severity of renal disease in B/W F1 mice. This gene may play a role in the class conversion of anti-dsDNA antibodies from IgM to IgG.

Animals↗
PubMed1983

Cardiac inhibitory action of constituents of the marine green alga Ulva pertusa.

As part of a search for substances from marine organisms, which exhibit inotropic effects, the chemical constituents of the marine green alga, Ulva pertusa were investigated. The fractionated extract was tested for inotropic effects on the isolated guinea pig atria. The aqueous layer obtained from the acetone extract of fresh algae was concentrated, and the residue was extracted with methanol. The methanolic extract was fractionated by chromatography using mixtures of aqueous methanol. Elution with 50% aqueous methanol afforded material that had a significant negative inotropic effect. Further purification of this material by high-performance liquid chromatography (HPLC) using methanol-water (2:5) afforded crystalline adenosine, which was shown to be the active substance of U. pertusa, causing a negative inotropic action.

Adenosine↗
PubMed1983

Lamellar bodies in heterotopic neurons of the cerebellum.

Small eosinophilic inclusion bodies were observed in the cytoplasm and processes of heterotopic neurons of the cerebellum in a case of Werdnig-Hoffmann disease. They were oval, triangular, or rod-shaped and measured 2-10 microns. Histochemically, these bodies contained a considerable amount of protein, lipid, and some polysaccharide, but no nucleic acid. The inclusion bodies were ultrastructurally identified with giant lamellar bodies. It was suggested that this body was a pathologic intraneuronal structure which is possibly related to the degenerating process of neurons.

Cerebellum↗
PubMed1983

Immunochemical evidence for multiple beta units of the class II molecule in the rat.

The RT1-B/D region-associated antigens which were serologically defined in the previous study (Ohhashi et al., 1981), were partially purified from membranes of a rat B cell leukaemia, KNL-14. Sequential immunoprecipitation test, with the partially purified 125I-B/Dak preparation using four different rat alloantisera, including a monoclonal antibody, disclosed three distinctive populations of beta units of the class II molecules. Highly purified beta units of three discriminable class II molecules were shown to have different structural properties in terms of molecular weights and of electrophoretic profiles on the isoelectric focusing. The beta units shifted to a position of higher molecular weight on SDS-PAGE under reducing condition, thus suggesting to carry intradisulfide bonds. Furthermore, the highly purified beta units cross-reacted with murine anti-Ia sera. The rebinding test revealed that at least two discriminable species of beta units cross-react with anti-I-Ak monoclonal antibody, whereas beta units purified by binding with the 1E4 monoclonal antibody cross-reacted with anti-I-Ab and/or anti-I-Ad antiserum. On the basis of structural and antigenic properties, we have postulated that the rat class II region can be divided into at least three subregions, each containing a locus which encodes a distinctive beta unit of the class II molecule.

Animals↗