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Biomedical subjects

C Kawai

Publications and source records attributed to C Kawai.

At least 343 records · Page 19Linked to original sources
PubMed1986

Familial hypertrophic cardiomyopathy mimicing typical dilated cardiomyopathy.

An autopsied patient who showed typical dilated cardiomyopathy (DCM)-like features and was pathologically diagnosed with hypertrophic cardiomyopathy (HCM) is presented. The patient, a 60-year-old male at the time of death, died of intractable congestive heart failure. At autopsy the heart weighed 570g and showed marked left ventricular (LV) dilatation with a thin wall (ventricular septum/free wall of the LV = 7 mm/8 mm). There was no evidence of significant stenosis in the extramural coronary arteries. Massive fibrosis was found in the middle and outer thirds of the ventricular septum and anterior wall of the LV (48% in the ventricular septum and 9% in the free wall of the LV). As myocytes were not present in the area with massive fibrosis, percent area of disarray was calculated excluding the area of massive fibrosis and found to be 30% in the ventricular septum. Based on the marked increase in the percent area of disarray, this case was diagnosed as HCM. The patient's 37-year-old son showed asymmetric septal hypertrophy on echocardiography (ventricular septum/posterior wall of the LV = 15 mm/11 mm), marked LV hypertrophy on electrocardiography, and diffuse and marked disarray by endomyocardial biopsy. There were also LV dilatation (LV diastolic dimension = 51 mm) and hypokinesis of the LV; as a result, a diagnosis of HCM with features of DCM was made.

Adult↗
PubMed1986

Effects of hypertrophy and allylamine-induced fibrosis on mechanical properties of isolated rat heart muscles with references to the pumping function of the intact heart in the same models.

To examine the effects of hypertrophy and fibrosis on myocardial mechanics, we studied isolated left ventricular papillary muscles from 6-month-old male SHR and allylamine-fed rats. In SHR, the peak developed tension (DT) and the maximum rate of tension development (dT/dt) were higher compared to control male Wistar-Kyoto rats (WKY). With 15 min of hypoxia, the DT and the dT/dt declined similarly in both groups and the ratios of DT and dT/dt to their prehypoxic values after 15 min of hypoxia were not different in the two groups. From allylamine-fed rats, only 4 papillary muscles had more than 25% interstitial fibrosis by point-counting (AL-B group), but 9 muscles had no fibrotic involvement and their left ventricular hydroxyproline concentration was normal (AL-A group). The myocardial diameters, the passive stiffness constant and the duration of isometric contractions at Lmax were increased in AL-B group, but the resting tension, the DT at Lmax and the force-velocity relations did not differ from controls. The mechanical properties of the AL-A group muscles were not different from controls. However, when pumping function was examined in the intact heart from the AL-A group, the LVEDP was increased and the peak cardiac output normalized by body weight was decreased. Thus, hypertrophied muscle from SHR shows hyperfunction without an increase in susceptibility to hypoxic stress. Even if fibrosis progresses, hypertrophy can compensate for the reduction in contractile component up to a certain degree.(ABSTRACT TRUNCATED AT 250 WORDS)

Allylamine↗
PubMed1986

[Immunological background of patients with dilated cardiomyopathy and myocarditis: clinical and experimental studies].

Immunogenetic mechanism may be involved in the pathogenesis of idiopathic cardiomyopathy. Viral myocarditis is considered a cause of dilated cardiomyopathy. In this study, we examined the major histocompatibility complexes (human leukocyte antigens: HLA) by microdroplet cytotoxicity test, lymphocyte subsets by laser flow cytometry, and the activity of lymphocyte blastoformation induced by phytohemagglutinin (PHA) and concanavalin A (Con A) in patients with cardiomyopathies (DCM) and myocarditis (MC). We also examined the incidence and histopathology of encephalomyocarditis (EMC) virus myocarditis in inbred strains of mice, and serial changes of T- and B-lymphocytes in the peripheral blood of DBA/2 mice inoculated with EMC virus by immunofluorescence techniques. The results were as follows: Major histocompatibility complex (HLA and H-2); HLA-B12 in patients with DCM and HLA-DR8 in patients with MC were more frequent than in controls. In EMC virus infection, differences were found in the frequency of occurrence of MC in inbred strains of A/J (H-2a), C57BL/6 (H-2b), BALB/c (H-2d), DBA/2 (H-2d) and C3H/He (H-2k) mice. Genetic mechanism may play a role heart similar to lesions in patients with DCM were seen in DBA/2 mice in the chronic stage of MC. in susceptibility to virus infection. Lymphocyte population study; OKT 8 (suppressor T-cell) was significantly lower in patients with DCM and hypertrophic cardiomyopathy (HCM) than in controls. There were no significant changes of lymphocyte subsets in patients with MC as compared with the controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

[201Tl myocardial scintigraphy and 13N-NH3 positron computed tomography in evaluating myocardial blood flow].

The early distribution of thallium-201 (Tl-201) is related to blood flow within the limits of the physiological range. We examined the ratio of myocardial uptake of Tl-201 to the total dose administered at rest and during exercise, in order to assess myocardial blood flow. The usual dose of Tl-201 (2-3 mCi) was diluted to 20 ml of normal saline and 15 ml were injected intravenously as a bolus. Subsequently the remaining 5 ml were injected in the same manner. Myocardial Tl-201 uptakes after the first dose were comparable to those of the second dose at rest when myocardial uptake immediately before the second injection was subtracted and multiplied by 3 (r = 0.98). This technique was applied during exercise to evaluate coronary reserve. Symptom-limited exercise was performed using a sitting ergometer and the first dose of Tl-201 was administered. After the routine scintigraphy with multiple views was completed, a second dose was given at rest. Myocardial uptake was greater during exercise than at rest by 32.6 +/- 15.1% (mean +/- SD) in 18 normal subjects. This was significantly greater than that of 20 patients with coronary artery disease (5.8 +/- 15.3%; p less than 0.005). Tl-201 scintigraphy has inherent limitations as to its quantitation, while positron scintigraphy using 13N-NH3 has some advantages for calculations. Percent myocardial uptake of 13N during exercise was practically equal to that at rest in six normal subjects (97.1 +/- 25.0%), but it was slightly reduced in patients with coronary artery disease (90.1 +/- 18.2%).(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Circulation↗
PubMed1986

[Asynchronous wall motion in patients with ischemic heart disease assessed by higher-order harmonics of the Fourier series].

To assess regional cardiac function in patients with ischemic heart disease (IHD), multigated blood-pool studies using higher-order harmonics of the Fourier series were performed for 14 normal persons and 37 patients with IHD. IHD was further divided into IHD (I) (EF greater than or equal to 50%) and IHD (II) (EF less than 50%). A pixel-by-pixel volume curve was simulated using second order harmonics of the Fourier series to create functional images of the following parameters: time to endosystole (TES), peak ejection rate (PER), time to PER (TPE), peak filling rate (PFR), and time to PFR (TPF). TES (SD), TPE (SD), and TPF (SD) were calculated as the standard deviations of left ventricular (LV) histograms of each phase, representing indexes of asynchronous wall motion. An LV volume curve was simulated using third order harmonics to calculate PFR, PFR/PER, and TPF/TPE, representing indexes of diastolic function. TES (SD) was abnormal in 10 cases (50%), and TPE (SD) was abnormal in seven cases (35%) of IHD (II). On the contrary, TPF (SD) was abnormal in three cases (18%) of IHD (I) and 15 cases (75%) of IHD (II), indicating that diastolic asynchronous indexes are more sensitive than systolic asynchronous indexes in detecting IHD. IHD (I) and IHD (II) showed lower PFR (2.32 +/- 0.55, 1.64 +/- 0.46 EDV/sec) and lower PFR/PER (0.84 +/- 0.15, 0.68 +/- 0.26) than those in normals (3.25 +/- 0.98 EDV/sec, 0.99 +/- 0.19), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Volume↗
PubMed1986

[Numbers and sizes of myocytes, amount of interstitial space, fibrosis and disarray in dilated cardiomyopathy].

The features characteristic of dilated cardiomyopathy (DCM) are dilatation of the left ventricular cavity without thickening of the wall, and decreased contractility of the left ventricle. The myocardial wall thickness depends on three variables: the number of muscle layers, the mean size of myocytes and the percent area of interstitial space. To clarify the histological pathogenesis of the special features of DCM, these three variables including wall thickness, fibrosis and disarray in the left ventricular wall of autopsied hearts were quantitatively measured in 10 patients with DCM, 10 patients with hypertrophic cardiomyopathy (HCM) and 20 patients with normal hearts (N). The heart weight was 651 +/- 128 g in the DCM group, 614 +/- 216 g in the HCM group, and 280 +/- 40 g in N group. The S (ventricular septum)/F (left ventricular free wall) of the wall thickness was 9 +/- 1/9 +/- 1 (mm) in DCM, 25 +/- 5/16 +/- 2 (mm) in HCM, and 13 +/- 1/13 +/- 1 (mm) in the N group. The S/F of % fibrosis was 9 +/- 5/11 +/- 4 in DCM, 14 +/- 4/8 +/- 5 in HCM, and 1 +/- 1/1 +/- 1 in N. S/F of the size (mu) of myocytes was 18 +/- 2/21 +/- 3 in DCM, 19 +/- 3/21 +/- 2 in HCM, and 13 +/- 1/14 +/- 1 in N. S/F of the numbers of muscle layers was 310 +/- 60/260 +/- 40 in DCM, 630 +/- 80/360 +/- 70 in HCM.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Detection of intracardiac shunt flow in atrial septal defect using a real-time two-dimensional color-coded Doppler flow imaging system and comparison with contrast two-dimensional echocardiography.

To evaluate the noninvasive detection of shunt flow using a newly developed real-time 2-dimensional color-coded Doppler flow imaging system (D-2DE), 20 patients were examined, including 10 with secundum atrial septal defect (ASD) and 10 control subjects. These results were compared with contrast 2-dimensional echocardiography (C-2DE). Doppler 2DE displayed the blood flow toward the transducer as red and the blood flow away from the transducer as blue in 8 shades, each shade adding green according to the degree of variance in Doppler frequency. In the patients with ASD, D-2DE clearly visualized left-to-right shunt flow in 7 of 10 patients. In 5 of these 7 patients, C-2DE showed a negative contrast effect in the same area of the right atrium. Thus, D-2DE increased the sensitivity over C-2DE for detecting left-to-right shunt flow (from 50% to 70%). However, the specificity was slightly less in D-2DE (90%) than C-2DE (100%). Doppler 2DE could not visualize right-to-left shunt flow in all patients with ASD, though C-2DE showed a positive contrast effect in the left-sided heart in 9 of 10 patients with ASD. Thus, D-2DE is clinically useful for detecting left-to-right shunt flow in patients with ASD.

Adolescent↗
PubMed1985

Septal Q wave in exercise testing: evaluation by single-photon emission computed tomography.

Changes of septal Q waves in lead V5 by exercise were evaluated with single-photon emission computed tomography. Coronary artery disease was present in 66 patients, 48 of whom had left anterior descending coronary artery (LAD) involvement. Forty-one subjects had normal coronary arteries. All patients under investigation were classified into 3 groups: group A (18 patients)--regression of Q amplitude during exercise; group B (48 patients)--progression or no change of Q wave or a new Q wave during exercise; and group C (41 patients)--no Q waves at rest and during exercise. Perfusion defects of the septum were calculated 3-dimensionally and expressed as a percent of the total septum. Seventeen patients (94%) in group A showed septal perfusion defects by exercise and all of them had LAD stenosis. Forty-three patients (90%) in group B showed no septal perfusion defects, but the others with perfusion defects had LAD stenosis. In group C, 23 of 41 patients (56%) had an LAD lesion, of whom 91% showed septal perfusion defects; none of the remaining 18 patients without LAD stenosis showed perfusion defects. The area of septal perfusion defects during exercise was larger in group A (62 +/- 19%) and in group C (52 +/- 19%) than in group B (23 +/- 9%) (groups A vs B, p less than 0.001; groups C vs B, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Circulation↗
PubMed1985

Coronary thrombolysis with urokinase infusion in acute myocardial infarction: multicenter study in Japan.

The efficacy of intracoronary administration of urokinase was evaluated in 514 patients with acute myocardial infarction (anterior, 296 patients; inferior, 195; lateral or posterior, 18; and anterior and inferior, five). The time between onset of chest pain and coronary arteriography was 0.5 to 81.0 hr with an average of 5.0 hr. Initial administration of nitrates resulted in recanalization of the coronaries in 9.3%. Subsequently, urokinase was infused into the coronary arteries, and coronary thrombolysis was successfully achieved in 66.8%. The success rate was low in a group with average infusion speed of more than 30,000 units/min or with a total dose of urokinase of 480,000 units or less. Complications, mainly arrhythmias, were present in 111 patients (33.2%) of the 334 who had successful thrombolysis and in 18 patients (10.8%) of the 166 with unsuccessful thrombolysis, but serious hemorrhage was rare and no fatal case was reported. Patients who had successful thrombolysis had less in-hospital mortality than those who did not (6.3 vs 13.3%). Thus, coronary thrombolysis can be achieved effectively and relatively safely with a sufficient amount of intracoronary urokinase administration in acute myocardial infarction.

Adult↗
PubMed1985

Myocardial positron computed tomography with 13N-ammonia at rest and during exercise.

To assess the value of myocardial-perfusion positron computed tomography (PCT) for the evaluation of coronary artery disease (CAD), 13N-ammonia PCT using a whole-body multislice PCT device was performed at rest and during exercise in 6 normal subjects and 19 patients with angiographically documented CAD. The 13N-ammonia distribution in the myocardium was assessed both qualitatively and quantitatively. At rest and during exercise, the tracer distribution was homogeneous in the 6 normal cases. In the 19 patients with CAD, regional hypoperfusion was observed in 14 cases (74%) at rest and in 18 cases (95%) during exercise. Additional perfusion abnormalities were detecting during exercise in 12 cases. Segmental analysis of the myocardial perfusion identified 30 out of 34 stenosed vessels (88%) during exercise, with only one false-positive finding of diseased vessels (specificity, 98%). For the quantitative analysis of myocardial perfusion by PCT, the percentage of change in the tracer concentration in the same region between the rest and stress images was calculated. The concentration was slightly increased in normal myocardial segments (14.4% +/- 5.8%; P less than 0.001), whereas in CAD, it was significantly decreased in segments with stenosed vessels (-18.0% +/- 18.3%; P less than 0.02). We conclude that 13N-ammonia PCT at rest and during exercise provides high-quality images, and is a sensitive and effective technique for detecting CAD and identifying individual stenosed vessels. Furthermore, this technique makes possible quantitative assessment of the coronary reserve function.

Adult↗