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Biomedical subjects

J Masuda

Publications and source records attributed to J Masuda.

At least 109 records · Page 6Linked to original sources
PubMed1989

[Partitioning and measurement of respiratory impedance into central and peripheral airways with catheter tip type transducer].

In this study, we have examined the availability of catheter tip type transducer for the partitioning of respiratory impedance. Total respiratory resistance and reactance from 1 to 20 Hz determined by forced oscillation method with random noise input in anesthetized dogs were partitioned by catheter tip type transducer into central airway resistance (Rc) and reactance (Xc) as well as peripheral resistance (Rp) and reactance (Xp). Intratracheal acetylcholine (0.1g) increased Rp at the wide frequency range (from about 1 to 20 Hz), although Rc did not change with it. The decreases of Rc at higher frequencies (over 12Hz) were produced by intratracheal salbutamol (10mg), whereas Rp did not change significantly. These results suggest that the predominant site of action of intratracheal acetylcholine and salbutamol is peripheral airway and central airway respectively. We have concluded that the respiratory impedance can be partitioned noninvasively with catheter tip type transducer without pneumothorax and hemorrhage caused with the retrograde catheter. This method can be applied clinically during general anesthesia or in intensive care.

Acetylcholine↗
PubMed1988

A nation-wide study of atherosclerosis in infants, children and young adults in Japan.

This paper reports the results of a nation-wide cooperative study of atherosclerosis in young, first generation Japanese with ages ranging from 1 month to 39 years, who were autopsied between 1978 and 1982 in hospitals distributed over the entire archipelago of Japan. Atherosclerotic lesions in 2320 aortas, 1620 coronary arteries and 344 cerebral arteries were classified into fatty streaks, fibrous plaques and complicated lesions and were then quantificated with the point-counting method. Atherosclerosis of aortas, coronary arteries and cerebral arteries, determined by surface involvement (SI) of atherosclerotic lesions and atherosclerotic index (AI), increased with age; the severest were seen in aortas, and then, with decreasing severity, in the coronary and cerebral arteries. Fatty streaks preceded the other lesions and accounted for the largest portion of the lesions in aortas and coronary arteries. Fibrous plaques and complicated lesions developed in the later decades of life. The patients with collagen diseases had a greater severity of aortic atherosclerosis in the 2nd and 3rd decades of life, than those without such disorders. Correlation of antemortem clinical data with SI and AI of each artery were analyzed, using simple correlation analysis and multiple regression analysis. Age, serum cholesterol and blood pressure were significantly and positively correlated with SI and AI of aortas and coronary arteries. Serum cholesterol was more strongly correlated with the extent of fatty streaks than was mean blood pressure and vice versa with that of fibrous plaques. Atherosclerosis of cerebral arteries, however, showed a significant correlation only with the factor of mean blood pressure. Therefore the susceptibility to risk factors varies with the artery in cases of early lesions of atherosclerosis in young Japanese.

Adolescent↗
PubMed1988

Autopsy study of incidence and distribution of cerebral amyloid angiopathy in Hisayama, Japan.

The incidence of cerebral amyloid angiopathy in a general population was evaluated in brains of 400 consecutive autopsies of residents of Hisayama, Japan (November 1971-October 1983). Six samples taken from frontal lobe, parietal lobe, temporal lobe, occipital lobe, hippocampus, and basal ganglia of the same side of each brain were stained with both hematoxylin and eosin and Congo red. The specimens were surveyed microscopically with polarized light for deposition of amyloid in the vascular wall. In 26 cases with brain hemorrhage, the region surrounding the hemorrhagic sites was further examined to study the probable causal relation between cerebral amyloid angiopathy and brain hemorrhage. Cerebral amyloid angiopathy was found in 40 of 218 men (18.3%) and 51 of 182 women (28.0%). The incidence increased with age in both sexes. The frontal lobe was most frequently affected (66 cases), followed by parietal lobe (65), occipital lobe (49), temporal lobe (44), and hippocampus (32); the putamen was never affected. The incidence of cerebral amyloid angiopathy did not correlate with blood pressure or with the severity of cerebral atherosclerosis. Among the 26 cases in which there was brain hemorrhage, only one cerebellar hemorrhage, in an 85-year-old man, was attributed to cerebral amyloid angiopathy. This case showed four microaneurysms in vessels, with cerebral amyloid angiopathy surrounding the hemorrhagic site. Thirty similar lesions were observed in eight cases without brain hemorrhage. Cerebral amyloid angiopathy may play an etiologic role in the development of brain hemorrhage through formation of angionecrosis and microaneurysm.

Adult↗
PubMed1987

[Pathogenesis of dilated cardiomyopathy: a study based on comparison of the clinical features with other related conditions].

To investigate the pathogenesis and pathophysiology of dilated cardiomyopathy (DCM), we studied 28 patients with DCM by echocardiography and endomyocardial biopsy, and compared their findings with those of 34 patients including eight with myocarditis, seven with alcoholics, 12 with hypertensives and seven patients with hypertrophic cardiomyopathy. All 12 patients in the hypertensive group had congestive heart failure without accompanying high blood pressure, and prominent dilatation and uniform wall motion abnormality of the left ventricle observed echocardiographically on admission. After medical management, both heart failure and the echocardiographic abnormalities gradually resolved. Those in the alcoholic group had larger left ventricles and uniform wall motion abnormality compared to those in the other groups. The myocarditis and hypertrophic cardiomyopathy groups had smaller left ventricles, non-uniform wall motion and larger % myocardial fibrosis. Both ventricles in the hypertrophic cardiomyopathy group were thicker than those of the other three groups. Each patient with DCM had individual echocardiographic abnormalities, which could be categorized as two subsets depending on the degree of left ventricular dilatation and uniformity of the wall motion. The one was characterized by a prominently dilated left ventricle and uniform wall motion abnormality similar to the alcoholic group, and the other had less marked left ventricular dilatation and heterogeneous wall motion abnormality similar to the myocarditis group. From these findings, it was suggested that there are common factors to specific myocardial disease in the pathogenesis and pathophysiology of DCM, and thus, DCM might include many subsets of different etiologies.

Adult↗
PubMed1987

[Pulsed Doppler echocardiographic findings in 117 professional cyclists].

To investigate the effect of long-term athletic training on the heart, pulsed Doppler echocardiography was performed in 117 male professional cyclists (Group C: 20-59 years of age), and 40 age- and sex-matched untrained normal controls (Group N). According to age, the subjects in each group were categorized in two subgroups: 74 cyclists (Group CI), 20-39 years of age and 43 cyclists (Group CII), 40-59 years of age; 24 control subjects (Group NI), 20-39 years of age and 16 control subjects (Group NII), 40-59 years of age. The average durations as professional cyclists were eight years in Group CI and 29 years in Group CII. The ratios of pre-ejection period to ejection time (LV-PEP/ET, RV-PEP/ET) as obtained from Doppler flow velocity patterns of the left and right ventricles (LV, RV) were used as parameters of systolic function. The peak flow velocities during rapid filling (LV-R, RV-R) and atrial systole (LV-A, RV-A), and the ratio of A to R (LV-A/R, RV-A/R) were used as parameters of diastolic filling dynamics. The parameters of systolic function of both ventricles and those of diastolic filling dynamics of the RV did not differ between Group C and Group N, Group CI and Group NI, and Group CII and Group NII. Study of the diastolic filling dynamics of the LV disclosed that Group C had a significantly higher LV-A/R (p less than 0.05) than did Group N; therefore, no significant differences between Group CI and Group NI, and Group CII had a significantly lower LV-R (p less than 0.005) and a higher LV-A/R (p less than 0.005) than did Group NII. Twenty-four hour ambulatory ECG monitoring was performed for 49 cyclists. Thirty cyclists aged 20-39 years were categorized in two groups according to their LV-A/R values: eight cyclists (Group A) with the LV-A/R greater than the mean + SD value (0.69) in Group NI and 22 cyclists (Group B) with the LV-A/R lower than or equal to 0.69. Nineteen cyclists aged 40-59 years were separated into two groups according to the LV-A/R value: 11 cyclists (Group A) with the LV-A/R values greater than the mean + SD value (0.89) in Group NII, and eight cyclists (Group B) with the LV-A/R equal to or less than 0.89.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1987

[A trial diagnosis of latent dilated cardiomyopathy].

To diagnose latent dilated cardiomyopathy (latent DCM), we performed loading echocardiography with Angiotensin II and ergometer exercise in 41 patients. Twenty-one patients were suspected of having latent DCM because of histories, of heart failure of myocarditis; 10 patients had DCM; and 10 normal persons served as controls. On angiotensin II loading, cardiac function deteriorated in the DCM group, but it was maintained in the normal controls. Nine patients in the latent DCM group showed the same pattern as normals (L1-group), and 12 did as the DCM group (L2-group). Although % fractional shortening, end-diastolic and end-systolic dimensions of the left ventricle did not differ between the L1 and L2-groups, the A/R, the ratio of the pulsed Doppler echocardiogram at the left ventricular inflow tract, was larger and the exercise change of the % fractional shortening and exercise tolerance were less in the L2-group than in the L1-group. Furthermore, the biopsy findings of the L2-group were similar to those of the DCM group in terms of myocardial degeneration, myocardial hypertrophy and interstitial fibrosis. Thus, patients in the L2-group were thought to have a risk for DCM, and were cases of latent DCM. Angiotensin II loading is thought to be useful for diagnosing such cases.

Angiotensin II↗
PubMed1986

[Malignant familial cardiomyopathy with sudden death, typical asymmetric septal hypertrophy and dilated cardiomyopathy-like features].

Twenty-one members of a family were traced for three generations including the propositus, who had typical dilated cardiomyopathy (DCM)-like features. Clinical, radiological, electrocardiographic and echocardiographic examinations were performed for 13 of 16 still living. Five of 21 members died including three of sudden death. Among living 16 members, five had congestive heart failure, greater than grade III of the NYHA, and cardiomegaly on chest radiography in five. Left ventricular hypertrophy, abnormal Q waves, and ST-T changes were observed on electrocardiography in two, five and eight members, respectively. Echocardiography revealed asymmetric septal hypertrophy (ASH) in four, two of whom had systolic anterior motion (SAM) of the mitral valve. Two had features simulating DCM, and five had mitral valve prolapse. Among six patients with ASH or features simulating DCM, four had cardiac catheterization, coronary angiography and endomyocardial biopsy. None had significant coronary stenosis, but all had high left ventricular end-diastolic pressure (LVEDP) (23 +/- 7 mmHg). Endomyocardial biopsy showed moderate myocardial cellular hypertrophy, interstitial myocardial fibrosis, nuclear changes and myocardial disarrangement, with features characteristic of HCM. In this family with malignant HCM, patients had various clinical features including typical HCM, simulated DCM, DCM coexisted with mitral valve prolapse, and sudden death occurred frequently.

Adolescent↗
PubMed1985

Cardiac disorders predisposing to development of cerebrovascular diseases in the Japanese. Data obtained at autopsy.

For a clear definition of the influence of cardiac disorders on the development of cerebrovascular diseases in the Japanese, we reviewed 1,162 consecutive autopsy records aged 20 years and over in the Department of Pathology, Kyushu University, Japan. All autopsies had been done between Nov. 1971 and Oct. 1981. Cerebral infarction was found in 101 out of 196 with any type of cardiac disorder. Frequencies of cerebral infarction in those with myocardial infarction, rheumatic heart disease, non-bacterial thromboendocarditis, and atrial fibrillation were higher than in those with no heart disease. These differences can be ascribed to the higher incidence of large and medium-sized cerebral infarction, including many cases of cerebral embolism originating from the heart. Only 3.4% of those with small cerebral infarction were assessed to be cases of embolism. Non-embolic cerebral infarction was more frequently noted in those with myocardial infarction and atrial fibrillation than in those with no heart disease. These differences were probably linked to concomitant progression of arteriosclerosis of the cerebral and coronary arteries. In this consecutive autopsy study, cerebral embolism was found in 35 cases, 10.9% of the total number of those with cerebral infarction.

Adult↗
PubMed1984

Poorly differentiated adenocarcinoma of the rectum in a nephrotic patient with focal segmental glomerulosclerosis.

We report herein a case of poorly differentiated adenocarcinoma of the rectum occurring in a nephrotic patient with focal segmental glomerulosclerosis. The neoplasm which first appeared to be a submucosal tumor occurred in a 29-year old Japanese man with a nephrotic syndrome for 2 years and 6 months. Autopsy disclosed a large tumor located between the rectum and urinary bladder. Renal specimens showed changes consistent with focal segmental glomerulosclerosis.

Adenocarcinoma↗
PubMed1984

A new model of cerebral arteriosclerosis induced by intimal injury using a silicone rubber cylinder in rabbits.

We designed a new model for studies on atherogenesis in cerebrovascular systems. Myointimal thickening in the rabbit cerebral arteries was induced following intimal injury produced by a silicone rubber cylinder with nylon thread and which was injected from the bifurcation of the right external and internal carotid arteries to embolize either the intracranial internal carotid or middle cerebral artery. Fifteen minutes after the cylinder had been removed, there was a denudation of the endothelium, and platelets adhered to the exposed subendothelium at the site of embolization of the cylinder. Within 3 days, this denuded surface was completely covered by regenerated endothelial cells, and intimal thickening was not observed. After 7 and 28 days, there was a striking myointimal thickening composed of smooth muscle cells in the fibroelastic stroma in the injured region. Permeability of the regenerated endothelium to horseradish peroxidase continued to be enhanced through the intercellular junctions and by increase of vesicular transport after the regenerated endothelial cells had completely covered the denuded area. These findings suggest that enhancement of permeability of plasma constituents of the regenerated endothelium plays an important role in the atherogenesis of cerebral arteries.

Animals↗
PubMed1983

Wernicke's encephalopathy in early pregnancy complicated by disseminated intravascular coagulation.

A 29 year-old Japanese woman with hyperemesis gravidarum became comatose and died. The autopsy revealed a typical case of Wernicke's encephalopathy complicated by disseminated intravascular coagulation (DIC). Repeated vomiting and parenteral nutrition without vitamins led to Wernicke's encephalopathy and a spontaneous abortion 24 h before death triggered the induction of DIC.

Abortion, Spontaneous↗