Search PubMed⌕ Search

Biomedical subjects

Y Tsuda

Publications and source records attributed to Y Tsuda.

At least 235 records · Page 13Linked to original sources
PubMed1987

Aplastic anemia associated with type A viral hepatitis--possible role of T-lymphocytes.

Posthepatitic aplastic anemia (PHAA) is rather uncommon. Most reported cases have developed after non-A, non-B or B type hepatitis. The only case of PHAA occurring after hepatitis A reported so far, was described by Smith et al., who diagnosed it by the long-term elevation of IgG-class antibody in response to hepatitis A virus. Recently, the detection of IgM-class antibody specific against hepatitis A virus (IgM anti-HAV) has been commonly employed for precise diagnosis of hepatitis A. The case reported here is the first case of PHAA occurring after hepatitis A to be diagnosed by radioimmunoassay of IgM anti-HAV. Furthermore, evidence is presented suggesting that the PHAA may have been an immune-related response. Addition of the patient's peripheral T-lymphocytes to cultures of her own bone marrow cells resulted in a reduction in the number of colony-forming units in culture (CFU-C).

Adult↗
PubMed1987

[Infarct size determined by emission computed tomography using 99mTc-PYP: effect of coronary thrombolysis].

Emission computed tomography with 99mTc-PYP was used to estimate infarct size in 38 patients with documented acute myocardial infarction. In the present study, the effect of thrombolysis with Urokinase on infarct size and on left ventricular function was assessed. Fourteen patients with acute myocardial infarction who underwent intracoronary thrombolysis within six hours after the onset of symptoms, and 24 patients who underwent conventional therapy were the subjects of this study. Infarct size was measured by drawing a region of interest around the myocardial pyrophosphate uptake for each tomographic slice. The boundary was then defined as 65% of the maximal count within the region of interest as determined by phantom volume studies. The total number of voxels was obtained by adding those in all slices and multiplying the sum by the voxel volume (0.205 ml per one voxel) to determine the infarct volume. Measurement of the 99mTc-PYP uptake on the tomographic image revealed an average infarct size of 100.1 +/- 36.0 ml (ranged 45 to 198). The calculated infarct volume correlated significantly with sigma CPK (p less than 0.01) and with left ventricular ejection fraction (p less than 0.01), but not with the peak CPK. In patients with acute inferior myocardial infarction, the mean infarct volume was 78.4 +/- 29.1 ml in the coronary thrombolysis group, and 105.1 +/- 33.7 ml in the conventional bypass graft treatment group (p less than 0.05). We concluded that successful intracoronary thrombolysis may reduce infarct size. ECT imaging with 99mTc-PYP to determine infarct size may be clinically applicable in patients with acute myocardial infarction.

Adult↗
PubMed1986

Influence of granulocyte elastase-like proteinase (ELP) on platelet functions.

The influence of granulocyte elastase-like proteinase (ELP) on platelet functions was investigated. ELP inhibited the platelet aggregations induced by a wide variety of agonists. The inhibition was marked in the case of receptor-mediated agonists such as thrombin, ristocetin, etc. It was moderate with the pervading agonist, arachidonic acid, and mild with the bypassing agonist, Ca2+ ionophore A23187. ELP inhibited the release of thromboxane A2 from platelets in the case of the platelet aggregation induced by thrombin. On the other hand, ELP did not inhibit the release of thromboxane A2 from platelets in the platelet aggregation induced by arachidonic acid or Ca2+ ionophore A23187. ELP suppressed the release of serotonin from platelets induced by thrombin, while it did not markedly suppress the release of serotonin induced by Ca2+ ionophore A23187. Treatment of platelets with ELP resulted in a slight increase of intraplatelet cAMP levels. These results suggest that ELP acts on receptors and inhibits platelet functions. As a results, ELP markedly inhibits the platelet functions such as aggregation or release of serotonin or thromboxane A2 stimulated by receptor-mediated agonists. ELP slightly elevates the cAMP level in the platelets, resulting in the mild inhibition of the platelet functions stimulated by the pervading agonist, arachidonic acid, or the bypassing agonist, Ca2+ ionophore A23187.

Adenosine Diphosphate↗
PubMed1986

Synthesis of plasmin substrates and relationship between their structure and plasmin activity.

The plasmin substrates, D-Ile-Phe-Lys-pNA (I), 3-MV-Phe-Lys-pNA (II), Ile-Phe-Lys-pNA (III), D-Pro-Phe-Lys-pNA (IV), CP-Phe-Lys-pNA (V) and Pro-Phe-Lys-pNA (VI), were synthesized by the conventional solution method and the kinetic parameters of their amidolysis by plasmin were determined. It was found that the free amino group of the D-amino acid in substrates (I) and (IV) made a contribution to an increment in affinity between the substrate and plasmin.

Chemical Phenomena↗
PubMed1986

Recurrent transient ischemic episodes after anticoagulation or bypass operation. Hemodynamic or embolic mechanism.

Three patients who suffered delayed transient ischemic episodes despite adequate anticoagulation or successful extracranial-intracranial (EC-IC) bypass anastomosis were studied. A hemodynamic mechanism was prominent in 1 patient with moderate orthostatic hypotension. After adequate anticoagulation he had further episodes of transient ischemia, which were finally controlled by an EC-IC bypass. Cerebral blood flow studies revealed flow changes with progression of the arterial lesion from stenosis to occlusion. The bypass was patent postoperatively, which suggested that the ischemia in this patient had been hemodynamic in origin. In the other patient the cerebral ischemic symptoms showed a remarkable improvement after the bypass operation. However, ischemia recurred after the operation until anticoagulants were started. Postoperative cerebral ischemia suggested microemboli, whereas preoperatively, it was presumably a hemodynamic phenomenon. In another patient where microembolism was more apparent, anticoagulation controlled the recurrent ischemia after a bypass operation. A hemodynamic as well as embolic mechanism needs to be considered in a cerebral ischemia which recurs after treatment.

Adult↗
PubMed1986

Effect of flunarizine on regional cerebral blood flow in common and complicated migraine. Pilot study.

Alterations of regional cerebral blood flow (rCBF) are at least epiphenomena of common and complicated migraine, but may lead to serious clinical complications. Since flunarizine seems to be effective in migraine prevention it may exert a beneficial influence on rCBF in migraine as well. rCBF was assessed using the 133Xe inhalation method in 5 patients with common and 8 patients with complicated migraine. Measurements were done interictally prior and after therapy with 15 mg flunarizine p.o. daily over a period of 4 weeks. Major abnormalities of grey matter flow were observed even interictally. Significant improvement of rCBF in initially hypoemic regions may be attributed to flunarizine therapy. These preliminary data suggest that calcium entry blockers may prevent the ischemic complications of migraine.

Brain↗
PubMed1986

Assessment of regional cerebral blood flow with 123I amphetamine single photon emission computed tomography in cerebrovascular disease. Semiquantitative analysis comparing IMP SPECT with the 133Xe inhalation method.

To compare the capacity of three-dimensional IMP single photon emission computed tomography (SPECT) with that of the two-dimensional 133Xe method in detecting focal perfusion abnormalities in cerebrovascular disease, flow measurements were performed with both methods in twenty patients. In order to enable correlation with 133Xe regional cerebral blood flow (rCBF) IMP SPECT images were subdivided into areas extending from the outer to the inner part corresponding to 32 regions of the 133Xe Cerebrograph. Between IMP counts/pixel and 133Xe rCBF, inter-hemispheric ratios correlated better in severe ischemia. Absolute mean values correlated in the affected hemisphere but not in the unaffected hemisphere. Regional evaluations revealed tendencies of IMP SPECT to be sensitive for low flow areas but to underestimate high flow areas, i. e. the 'luxury perfusion syndrome', as compared with the 133Xe method.

Amphetamine↗
PubMed1986

Hyperfrontal distribution of regional cerebral blood flow and vascular CO2 reactivity in normal subjects and disturbances in ischemic cerebrovascular disorders.

The distributions of regional cerebral blood flow (rCBF) and CO2 reactivity were estimated in normal subjects and in patients with ischemic cerebrovascular disorders, using the 133Xe inhalation method. In the normals, hyperfrontal and hyper-fronto-parietal distributions of rCBF and CO2 reactivity were observed. In the patients, the differences in mean rCBF values between anterior and posterior regions decreased in the affected hemisphere. Comparison between the hemispheres revealed that the anterior regions had a decreased mean rCBF value in the affected hemisphere. The CO2 reactivity in the patients was generally decreased in both hemispheres, but not significantly. The originally existing, different distributions of rCBF and CO2 reactivity in normals must be considered in the evaluation of disturbances of vascular reactivity in patients with cerebral disorders.

Adult↗