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Biomedical subjects

C Kawai

Publications and source records attributed to C Kawai.

At least 253 records · Page 14Linked to original sources
PubMed1988

Regulation of renin-like enzyme in cultured human vascular smooth muscle cells.

Cultured human arterial smooth muscle cells produced an immunologically specific renin-like enzyme. The renin-like enzyme in the culture medium was mostly an inactive form; the proportion of the active form in the cell was 30 to 75%. Phorbol 12-myristate 13-acetate, N'-O'-dibutylyladenosine 3', 5'-monophosphate and isoproterenol with theophylline increased the renin-like enzyme in the medium and in the cell, dose dependently. Endothelial cell growth supplement also increased the renin-like enzyme produced by cultured vascular smooth muscle cells, and heparin promoted the effects of endothelial cell growth supplement. The existence of the regulation of the renin-like enzyme produced by cultured vascular smooth muscle cells strongly suggests the existence of a local renin angiotensin system in human vascular walls.

Cells, Cultured↗
PubMed1988

Platelet aggregation and thromboxane B2 release in patients with acute myocardial infarction--their relation to coronary patency.

Platelet function in the aortic blood in 39 patients who underwent intracoronary thrombolysis with urokinase was evaluated in the acute stage of myocardial infarction and after 4 weeks. The patients were classified into 2 groups according to the patency of the infarct vessel shown by coronary arteriography before urokinase administration. In the acute stage, 26 patients with completely occluded infarct vessel (group 1) showed a decreased level of platelet aggregation induced by adenosine diphosphate or arachidonic acid as compared with 13 patients with patent infarct vessel (group 2). The platelet aggregation in group 1 increased 4 weeks later and both groups showed similarly enhanced platelet aggregation levels as compared with normal controls. Like platelet aggregation, serum thromboxane B2 production in group 1 was lower than that in group 2 in the acute stage. Plasma thromboxane B2 levels in the aorta in both groups were significantly elevated in the acute stage, and were normalized after 4 weeks. This elevation of thromboxane B2 seems to be due to its washout from the infarct vessel, because plasma thromboxane B2 levels were significantly higher in the great cardiac vein than those in the aorta after successful reperfusion in group 1 or group 2. In conclusion, despite a significant elevation in plasma thromboxane B2 levels, platelet aggregation and serum thromboxane B2 production relatively decrease in patients with totally occluded infarct vessel. The patency of the infarct vessels should be taken into account when evaluating platelet function in acute myocardial infarction.

Adult↗
PubMed1988

Enhancement of coronary thrombolysis with plasminogen pro-activator by pretreatment with heparin.

The effect of pretreatment with heparin on coronary thrombolysis by plasminogen pro-activator was studied in 20 dogs with a 1-h old clot in the left anterior descending coronary artery. The clot was induced by placement of a copper coil and thrombolysis was confirmed angiographically. Intravenous administration of plasminogen pro-activator at a rate of 5 micrograms/kg/min (group 1; n = 5) and 20 micrograms/kg/min (group 2; n = 5) after pretreatment with heparin (300 IU/kg) induced thrombolysis in 31 +/- 4 min and 14 +/- 2 min, respectively. When plasminogen pro-activator was administrated intravenously at a rate of 20 micrograms/kg/min without heparin pretreatment (group 3; n = 5), the infusion interval for successful thrombolysis was prolonged to 45 +/- 6 min, which was significantly longer than that in groups 1 and 2 (p less than 0.001). In these three treatment groups, thrombolysis was not associated with severe alteration in plasma hemostatic factors (fibrinogen and alpha 2-antiplasmin). An evaluation of plasma urokinase activities using a chromogenic substrate S-2444 did not show that heparin increased the plasma urokinase activities. By increasing the dose of plasminogen pro-activities. By increasing the dose of plasminogen pro-activator to 80 micrograms/kg/min, successful reperfusion was rapidly obtained in 25 +/- 5 min without heparin pretreatment (group 4; n = 5); this was significantly faster than the results seen in group 3 (p less than 0.001). An analysis of urokinase activities showed that plasminogen pro-activator was fully converted to urokinase, which induced complete depletion of fibrinogen and alpha 2-antiplasmin.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

A case of myocarditis with immunological identification of myocardial and peripheral lymphocyte subsets.

Immunological identification of lymphocyte subsets in a patient with myocarditis revealed an increase in myocardial OKT 11 (pan T), OKT 4 (inducer/helper T) and OKT 8 (suppressor/cytotoxic T) subsets associated with a transient decrease in the percentage of circulating OKT 3 (pan T) and OKT 4 (inducer/helper T) subsets. This decrease may be explained by the accumulation of these subsets in the diseased myocardium. Specific antigenic markers on lymphocytes at the site of myocardial inflammation in the acute stage of myocarditis differ from those on corresponding peripheral lymphocytes. This observation may highlight the immuno-pathogenetic mechanisms involved in the development of myocarditis.

Adolescent↗
PubMed1988

The concentration of serum lipids in Zen monks and control males in Japan.

The concentrations of total, low density lipoprotein (LDL), and high density lipoprotein (HDL) cholesterol, triglyceride and apoprotein B have been examined in Zen monks whose intake of animal products was almost negligible for 2 to 8 years, and in age-matched (24 to 35 years) control Japanese males who eat Western style food. The mean levels of total, LDL- and HDL-cholesterol, and apoprotein B were 135.1 +/- 16.7, 73.0 +/- 11.6, 50.4 +/- 9.6, and 70.6 +/- 15.6 mg/dl, respectively in Zen monks. These levels were 28.5, 32.8, 18.8, and 23.9% lower in Zen monks than in control Japanese males. These values are statistically significant compared to those of the controls (p less than 0.01). There were no significant changes in the level of triglyceride in both groups.

Adult↗
PubMed1988

[Dual energy emission computed tomography with 99mTc pyrophosphate and 201T1 in evaluating coronary reperfusion therapy in patients with acute myocardial infarction].

To evaluate the clinical significance of scintigraphic overlap of thallium-201 (201T1) and technetium-99m pyrophosphate (99mTc), we observed 28 patients with acute myocardial infarction (AMI) in whom coronary reperfusion was attempted. All patients underwent dual energy emission computed tomography (D-ECT) on the third post AMI day which facilitated comparing 99mTc and 201T1 images from identical slices simultaneously. The scintigraphic results of the 28 patients were as follows: (table, see text) In conclusion, (1) significant 201T1 and 99mTc overlap on D-ECT suggest very early and successful reperfusion, and (2) none of the patients with unsuccessful reperfusion exhibits overlap.

Diphosphates↗
PubMed1988

Detection of early myocardial infarction in formalin-fixed, paraffin-embedded tissue.

Whether the early infarct area in formalin-fixed, paraffin-embedded tissue could be delineated by the immunohistochemical method using myoglobin-antibody was studied in 23 pig hearts without collateral circulation. Five hearts were examined at 20 minutes, 2 hours, 4 hours, and 6 hours after occlusion of the distal one third of the left anterior descending coronary artery, respectively. Three pigs were killed 24 hours after occlusion. Heart rate and aortic pressure before and after occlusion did not change in any groups. The subepicardial and subendocardial regional blood flows were reduced to almost zero in all hearts after occlusion (0.88 +/- 0.10 to 0.02 +/- 0.02 mL/g/min). Slight myoglobin defects in the ischemic tissue were noted in the five pigs examined 2 hours after occlusion and definite myoglobin defects were detected in all pigs examined at 4, 6, and 24 hours after occlusion. Nitrotetrazorium blue stain of myocardial tissue before formalin fixation showed slight demarcation of the ischemic area at 4 hours after occlusion and definite demarcation at 6 and 24 hours after occlusion. Slight demarcation was noted at 2 hours after occlusion in Masson trichrome stain and 4 hours after occlusion in the hematoxylin-eosin stain. However, definite demarcation of the ischemic area was seen in Masson trichrome stain only at 24 hours after occlusion and was not noted in hematoxylin-eosin stain even at 24 hours after occlusion. Our previous electron microscopic study revealed that, in the pig heart, irreversible cellular damage was transmurally seen at two hours after occlusion of the coronary artery. Therefore, a definite myoglobin defect reflects irreversible cellular damage such as infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

[Venous flow velocity patterns and cardiac function studied by Doppler echocardiography].

To study the relations of central venous flow velocity (VFV) to cardiac pump function, hepatic venous flow velocity was recorded using Doppler echocardiography in six normal subjects and 47 patients with heart disease, of whom 28 had sinus rhythm and 19, atrial fibrillation. The area under the VFV profile during systole and diastole in a cardiac cycle was computed, and termed the VIs (systolic time-velocity integral) and VId (diastolic time-velocity integral), respectively. VIs was divided by the sum of VIs and VId [VIs/(VIs + VId)], and this was termed the VI ratio. The cardiac index (CI) was estimated by Doppler echocardiography. In normal subjects, the VFV pattern in a cardiac cycle was biphasic, the systolic VFV being dominant. In patients with atrial fibrillation, the systolic VFV was attenuated or absent, the diastolic VFV being dominant. The CI correlated well with the VI ratio (r = 0.80; p less than .001) in 14 patients with atrial fibrillation except for five patients with tricuspid regurgitation. Four patients in whom atrial fibrillation converted spontaneously to sinus rhythm showed an increase in the CI and the VI ratio according to the CI-VI ratio relationship. In patients with sinus rhythm, the CI tended to decrease as the VI ratio increased. In 15 patients who had a VI ratio of over 0.75, the CI correlated inversely with the VI ratio (r = -0.70; p less than 0.01). Three of four patients who had the VI ratio of 1.0 died of congestive heart failure. Although there was positive correlation between the CI and VI ratio in patients without effective atrial contraction, there was inverse correlation in patients with effective atrial contraction. It is suggested that the VI ratio could be a good indicator of cardiac pump function.

Adolescent↗
PubMed1988

Value and limitation of stress thallium-201 single photon emission computed tomography: comparison with nitrogen-13 ammonia positron tomography.

The diagnostic value of exercise 201Tl single photon emission computed tomography (SPECT) for assessing coronary artery disease (CAD) was comparatively evaluated with exercise [13N] ammonia positron emission tomography (PET). Fifty-one patients underwent both stress-delayed SPECT imaging using a rotational gamma camera and stress-rest PET imaging using a high resolution PET camera. Of 48 CAD patients, SPECT showed abnormal perfusion in 46 patients (96%), while PET detected perfusion abnormalities in 47 (98%). The sensitivity for detecting disease in individual coronary arteries (greater than 50% stenosis) was also similar for SPECT (81%) and PET (88%). When their interpretations were classified as normal, transient defect, and fixed defect in 765 myocardial segments, SPECT and PET findings were concordant in 606 segments (79%). However, 66 segments showed a fixed defect by SPECT but a transient defect by PET, whereas there were only nine segments showing a transient defect by SPECT and a fixed defect by PET. PET identified transient defects in 34% of the myocardial segments showing a fixed defect by SPECT. We conclude that both stress SPECT and PET showed high and similar sensitivities for detecting CAD and individual stenosed vessels. Since stress-delayed SPECT with single tracer injection detected fewer transient defects, it may underestimate the presence of myocardial ischemia, compared with high resolution PET imaging with two tracer injections.

Adult↗
PubMed1988

[Myocardial blood flow and glucose metabolism in patients with myocardial infarction evaluated by positron emission tomography: comparison with left ventriculography].

Myocardial positron emission tomography (PET) using N-13-ammonia (NH3) and F-18-fluorodeoxyglucose (FDG) was performed in 16 patients with myocardial infarction to assess myocardial blood flow and glucose utilization. These PET data were also compared by left ventriculography. N-13-ammonia PET study was performed at rest and after supine ergometer exercise as a measure of myocardial blood flow, and the F-18-FDG PET study was performed at rest after more than five hours' fasting as a measure of glucose utilization. The N-13-ammonia PET study revealed hypoperfused regions in 15 of 16 patients (94%) corresponding to the infarct regions identified by electrocardiography and by cardiac catheterization. In 12 of 16 patients (75%) these hypoperfused regions expanded with exercise. FDG uptake was observed in the hypoperfused regions, especially in stress-induced ischemic ones. Increased uptake of FDG was more often observed in patients with mildly hypokinetic wall motion on left ventriculography. However, FDG PET studies demonstrated diffuse uptake of FDG in some of the akinetic and dyskinetic segments.

Adult↗
PubMed1988

[Left ventricular wall thickness in hypertrophic cardiomyopathy: comparisons of measurements by magnetic resonance imaging, cineangiography, and echocardiography].

To evaluate the usefulness of magnetic resonance imaging (MRI) in measuring regional wall thickness of the left ventricle, 11 patients with hypertrophic cardiomyopathy (HCM) were imaged. The measurements were compared with those obtained by two-dimensional echocardiography (2D-echo) and cineangiography. Regional wall thickness was ascertained at six locations including the base, middle, and apex of the interventricular septum (IVS) and left ventricular posterior wall (LVPW) from the two selected transverse sections. All of these six locations were also measured for the IVS by biventriculography and for the LVPW by left ventriculography with the left anterior oblique view. Only the base was measured for both the IVS and LVPW using 2D-echo because of the difficulty in obtaining good images for the middle and apex of the left ventricle. The measurements by MRI correlated well with those obtained by 2D-echo and cineangiography in the majority of locations. At the base, where the wall thickness was measured by the three methods, the measurements of the IVS correlated well each other (r = 0.63 to 0.81). However, a good correlation was obtained only between 2D-echo and MRI for the LVPW r = 0.75. The correlation between MRI and cineangiography was generally good for the IVS at any levels (r = 0.76 to 0.87), but not for the LVPW. This was partially due to the narrow range of data for the LVPW as well as to the difficulty in determining the epicardial border in left ventriculograms. In conclusion, regional wall thickness can be correctly measured by MRI in any locations of the left ventricle even at the apex, where measurement is difficult by other methods.

Adolescent↗