Search PubMed⌕ Search

Biomedical subjects

T Yoshimura

Publications and source records attributed to T Yoshimura.

At least 613 records · Page 34Linked to original sources
PubMed1988

Postnatal changes in plasma burst-promoting activity (BPA) levels in preterm infants.

Two-stage cell culture assays were used to determine burst-promoting activity (BPA) levels in the plasma of untransfused premature infants during the early anaemic period. The plasma BPA levels decreased during the early phase of the postnatal fall in haemoglobin and the mean plasma BPA levels at 2 and 4 weeks of age were significantly lower (24 +/- 9% and 20 +/- 14%) than those of normal adults (53 +/- 17%). After 8 weeks of age, plasma BPA levels increased markedly in correlation with the recovery of erythropoiesis. Inhibitors of erythroid colony growth were not significantly elevated in the plasma of premature infants. These results suggest that BPA may act as a regulator of erythropoiesis in preterm infants along with erythropoietin.

Adult↗
PubMed1988

Characteristics of contractile response of isolated portal veins from chronic portal hypertensive rats under altered levels of external K+, Ca2+, and norepinephrine concentrations: a comparison with normal Wistar rats.

We studied contractile properties of portal veins isolated from chronic portal hypertensive rats (PHR) resulting from liver cirrhosis, a model obtained by repeated subcutaneous injections of CCl4 (2 mg/kg) twice weekly for over 45 weeks. Portal venous pressure in vivo was significantly higher in PHR (167.0 +/- 38.7 mmH2O) than in the control normal Wistar rats (NWR) (102.0 +/- 25.5 mmH2O). A pair of portal veins from PHR and NWR were mounted longitudinally in an organ bath and perfused with Tyrode's solution with different K+, Ca2+, and norepinephrine concentrations. The isometric tension was measured by a strain-gauge. Under control conditions, spontaneous phasic contractile force, corrected by cross-sectional area, was greater, and the frequency was lower in PHR than in NWR preparations. The averaged peak contractile force measured at different [K]o (5.4-86.4 mM) was also greater in PHR than in NWR. Force of the tonic contraction measured at different [Ca]o (0.45-5.4 mM), under conditions of 86.4 mM [K]o was significantly larger in PHR than in NWR preparations. However, the Ca2+ sensitivity of both preparations was the same. D-600 (greater than or equal to 0.1 microM) inhibited the tonic contraction in both preparations with an identical sensitivity to the drug. In the presence of norepinephrine (10 microM), the Ca2+ sensitivity of the tonic contraction increased both in PHR and NWR preparations. The increase was more pronounced in PHR and was completely reversed in the presence of the alpha 1-adrenoceptor blocker, prazosin (0.1 microM). The alpha 1-adrenoceptor sensitivity to norepinephrine was not altered in PHR preparations. The rate of Ca2+ release and uptake of intracellular Ca2+ seemed identical in both preparations. Thus, in the absence of norepinephrine, the phasic and tonic contractile forces of portal veins from PHR are larger than that of NWR, probably due to increased membrane Ca2+ permeability. The PHR preparations have a higher affinity for external Ca2+ in the presence of norepinephrine, an additional factor contributing to elevation of portal blood pressure in the presence of chronic liver cirrhosis.

Animals↗
PubMed1988

Protein C in human plasma determined by homogeneous enzyme immunoassay with use of a centrifugal analyzer.

We describe the simple and rapid enzyme immunoassay of protein C in human plasma with use of a Cobas Fara centrifugal analyzer. The antibody, labeled with horseradish peroxidase, is reacted with antigen (protein C) for 15 min. The peroxidase activity of the resulting antigen-antibody conjugate is measured at 500 nm for 5 min in the presence of excess H2O2, phenol, and 4-aminoantipyrine, as compared with that of free conjugates. Results are calculated from a stored standard curve and expressed as a percentage of the value determined for a pooled specimen of normal adult plasma. The standard curve is linear from 0% to 200%. The CV is generally less than 4% for different concentrations of protein C. In liver cirrhosis, hepatocellular carcinoma, therapy with warfarin, thrombosis, and disseminated intravascular coagulation, protein C concentrations are about 40-70% of normal. Results obtained with the present homogeneous enzyme immunoassay correlated well with those by enzyme-labeled immunosorbent assay (r = 0.97).

Adult↗
PubMed1988

[Morphological characteristics of the left ventricle with volume-and pressure-overload in valvular heart diseases].

There are some cases in which pump function of the left ventricle (LV) is not sufficiently improved despite of successful operation, especially in advanced hypertrophy. The impaired pump function is believed to result from irreversible myocardial damage. Thus, the present study is designed to make clear the histopathological changes of the LV muscle in hypertrophied hearts. Fifty-six patients with volume-overloaded hearts (27 with AR, 24 with MR, and 4 with AR and MR) and 10 patients with AS were examined. Cardiac muscle specimens for histological examination were obtained from the LV anterior wall. In volume-overloaded hearts, the muscle cell diameters were correlated with both LV dimension (LVDd and LVDs) and LV volume index (LVEDVI and LVESVI). The progress of interstitial fibrosis was correlated with LV volume index. Five of the 9 patients with massive myocardial hypertrophy (in all cases, muscle cell diameter was greater than 30 microns) did not show any improvement in histological figure after operation and displayed persistent postoperative LV dilatation. Patients with either LVDd greater than 75mm and LVDs greater than 55mm or LVEDVI greater than 200ml/m2 and LVESVI greater than 100ml/m2, whose hearts showed massive myocardial hypertrophy and severe fibrosis, tended to have postoperative cardiac dysfunction. In pressure-overloaded hearts, the muscle cell diameters were correlated with LVPWTh and LVESVI. Noteworthily, fibrosis and degeneration of muscle fibers were slight as compared with advanced myocardial hypertrophy.

Cardiomyopathy, Hypertrophic↗
PubMed1988

Molecular weight of tumor necrosis factor determined by gel permeation chromatography alone or in combination with low-angle laser light scattering.

The molecular weight of human recombinant tumor necrosis factor was determined at neutral pH by gel permeation chromatography alone or in combination with low-angle laser light scattering. Mean values of 39,200 +/- 800 and 48,800 +/- 900, respectively, were obtained by the two analyses. The results resolve the apparent discrepancy in the reported values of the molecular weight of this cytokine, confirming that it exists as a trimer in neutral solution with a molecular weight of about 50,000.

Chromatography, Gel↗