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Biomedical subjects

R Okada

Publications and source records attributed to R Okada.

At least 127 records · Page 7Linked to original sources
PubMed1990

Interstitial cell infiltrate and myocardial fibrosis in dilated cardiomyopathy: a special type of cardiomegaly corresponding to sequelae of myocarditis.

We examined the relationship between interstitial cell infiltration and myocardial fibrosis in patients with clinically diagnosed dilated cardiomyopathy (DCM). Forty-two cases of DCM were divided into two groups, according to the mean number of the interstitial round cells per 10.2 x 10(4) square microns (Nic): the inflammatory group (Nic greater than or equal to 5) and noninflammatory group (Nic less than 5). The 12 cases in the inflammatory group were clinically similar to the 30 cases in the non-inflammatory group, but the inflammatory group exhibited a significantly (P less than 0.001) larger area of myocardial fibrosis (34.8% +/- 12.8% vs 17.5% +/- 8.2%), a significantly (P less than 0.01) higher frequency of diffuse perimyocytic-type fibrosis (83% vs 23%), fewer myocardial cells in the left ventricular wall (170 +/- 70 fibers vs 216 +/- 81 fibers), and significantly (P less than 0.01) greater hypertrophy of the myocytes (18.3 +/- 3.4 vs 15.3 +/- 2.7 microns). In addition, cases exhibiting marked fibrosis (fibrosis area greater than or equal to 25% of the myocardium) had a significantly higher Nic score (8.3 +/- 6.8) compared to cases with the less fibrotic type of DCM (4.0 +/- 5.7). We speculate that persistent or preceding inflammatory cell infiltration induces the myocardial fibrosis, especially the diffuse perimyocytic type, in the fibrosis-predominant type of DCM. Therefore, most of these cases may be a sequela of myocarditis, and more correctly termed post-myocarditic cardiomegaly.

Cardiomyopathy, Dilated↗
PubMed1990

An autopsy case of cardiomyopathy with restrictive physiology in a child.

An autopsy case of cardiomyopathy with restrictive physiology associated with subendocardial myocardial necrosis and fibrosis in a seven-year-old child is described. Cardiac catheterization showed high left ventricular end-diastolic pressure with a dip-and-plateau pattern. Macroscopically, marked dilatation with fibroelastosis in both atria and mild dilatation in both ventricles were observed. Histologic examination revealed extensive subendocardial necrosis with marked disorganization of myocardial cells and moderate arteriolosclerosis. We speculate that these extensive myocardial lesions, which contributed to the restrictive hemodynamic changes, could have been induced by anoxia or a Ca2+ transport abnormality of unknown cause.

Cardiomyopathy, Restrictive↗
PubMed1990

[Two autopsied cases of arrhythmogenic right ventricular dysplasia].

Autopsy studies of arrhythmogenic right ventricular dysplasia (ARVD) have rarely been reported, and its etiology remains unknown. The present report describes a detailed histopathological study of two autopsied cases of ARVD. Case 1: This 21-year-old man experienced palpitation accompanied by syncope. He died after ventricular tachycardia of right ventricular origin. The heart weighed 365 g and the right ventricular cavity was markedly dilated. The distribution of fatty tissue was roughly limited to the middle layer of the free wall, replacing the myocardium with fatty degeneration. Medial hyperplasia of the small arteries within the fatty tissue was also observed. Fibroelastosis was observed in the left ventricular endocardium. In the conduction system, fatty tissue was found in the sinus node. In addition, medial hypoplasia was observed in the pulmonary arteries. Case 2: This 32-year-old man who had had an arrhythmia for 10 years died of ventricular tachycardia of right ventricular origin. His older brother also died of heart disease. His heart weighed 515 g and both the right and left ventricles were dilated. Fatty tissue, unlike that in Case 1, was shown to markedly infiltrate from the epicardium into both the right and left ventricular walls. In the right ventricular wall, muscle layers disappeared in some portions. In the conduction system, fatty tissue was observed in the sinus node. Although ARVD may be considered a syndromic entity, individual cases are different in terms of pathological morphology, with possible variations in the etiology and pathogenesis.

Adipose Tissue↗
PubMed1989

Autopsy statistics on the relative frequency of acute myocardial infarction in the Japanese mental workers and the unemployed during the two oil-crises periods.

In order to investigate whether job induced emotional stress, arising from socioenvironmental disasters would act as a trigger for the onset of AMI, the author reviewed all pathological autopsies throughout Japan 15 years old and over. Data was obtained from publications of the "Annual of the Pathological Autopsy Cases in Japan" for the years 1966-1968 (a period of high economic growth), 1973-1975 (1974, the year of the first oil crisis), and 1978-1980 (1979, the year of the second oil crisis). Relative frequencies of AMI were significantly higher during the years of both oil crises than in both the preceding and following years (2.6% in 1973, 3.7% in 1974, 3.0% in 1975; 2.8% in 1978, 3.2% in 1979, and 2.0% in 1980), and in each of three years of the high economic growth period (1.9-2.2% in 1966-1968). The proportions of managers and officials among AMI victims were significantly higher in the years of both oil crises than in both the preceding and following years (13.4% in 1973, 17.5% in 1974, 12.5% in 1975; 11.6% in 1978, 15.8% in 1979, and 11.1% in 1980). Moreover, there was a significantly higher value in the year of first oil crisis than in each of three years of the high economic growth period (11.7-13.1% in 1966-1968). The proportions of "out of job" persons were also significantly higher in the years of both oil crises than in the preceding years (24.0% in 1973, 29.3% in 1974, 27.8% in 1975; 24.1% in 1978, 29.1% in 1979, and 27.4% in 1980). For 11,199 randomly selected autopsies, the proportions of AMI in the above two occupational groups were significantly higher in the years of both oil crises than in the preceding years. Moreover, the proportion of "out of job" persons was significantly higher in the year of first oil crisis than in each of three years of the high economic growth period. A similar trend was noted among professional and technical workers, with more AMI occurring in this group during the years of both oil crises than in both the preceding and following years but without statistically significant difference.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1989

Relation between coronary stenosis and myocardial lesions determined by a semiquantitative approach to myocardial fibrosis and hypertrophy due to ischemia.

To clarify the cause of myocardial hypertrophy in ischemic heart disease, the relation between the extent of fibrosis and myocyte diameter was examined in patients with cardiac hypertrophy of unknown etiology except for coronary sclerosis. In 79 unselected cases, the heart weight tended to be higher in patients with severe coronary stenosis and fibrosis. In a morphometric study of 33 additional hearts of patients without a clinical history of hypertension, valvular disease or diabetes mellitus, 15 of which had anterior infarction, a positive correlation (r = 0.63) was observed between myocyte diameter and the percent area of fibrosis in the anterior wall of the left ventricle. In the heart of patients with severe coronary stenosis (more than 75% luminal narrowing), the regression coefficient was 0.83. The hearts of 8 patients with nontransmural infarction showed a strong correlation between myocyte diameter and fibrosis, compared with the hearts of 7 patients with transmural infarction. In most cases, the main mechanism of hypertrophy in ischemic heart disease was considered to be compensatory hypertrophy for existence of myocardial fibrosis.

Adult↗
PubMed1989

The role of the nigrotegmental GABAergic pathway in the propagation of pentylenetetrazol-induced seizures.

Recent evidence suggests that the substantia nigra (SN) may be involved in the modification of various experimental epilepsy models. We determined the role of gamma-aminobutyric acid (GABA)ergic activity of the SN and the target sites of SN efferents, the pedunculopontine nucleus (PPN) and superior colliculus (SC), in pentylenetetrazol-induced seizures in rats. Bilateral administration of a GABA agonist (muscimol) into the SN significantly reduced seizure severity; its administration into the PPN significantly augmented seizure severity; administration into the SC did not alter the seizure severity. On the other hand, infusion of a GABA antagonist (bicuculline) into the PPN revealed a protective effect against seizures. Our findings indicate that the nigral GABAergic projections to the PPN play an important role in seizure propagation. Thus, PPN neurons may be a possible target site of nigral output modulating seizure propagation.

Animals↗
PubMed1989

Nonspecific myocarditis: a statistical and clinicopathological study of autopsy cases.

Among a total of 634,440 autopsy cases in "The Annuals of Pathological Autopsy Cases in Japan" from 1958 to 1984, 929 cases with nonspecific myocarditis were registered. The average incidence was 0.15%, fluctuating around 3- to 5-year intervals with a remarkable rise observed after 1974. The major complications in cases of myocarditis were pneumonitis, hepatitis or hepatic cirrhosis, pancreatitis, malignancies, lymphatic or thymic involvements. A clinicopathological study of 36 cases of myocarditis and 27 cases of postmyocarditic cardiomegaly indicated a classification of acute, subacute, healing and chronic or recurrent stages as well as dilatation-hypertrophy- and right ventricle-dominant types. Acute myocarditis was characterized by diffuse inflammatory cell infiltration and showed various types of arrhythmias and shock. Subacute myocarditis showed ventricular dilatation, edematous interstitium and severe congestive heart failure. Chronic myocarditis with dilatation and/or hypertrophy and irregular fibrosis included right ventricular involvement, endomyocardial disease, sick sinus syndrome in selected cases, congestive heart failure in most cases, and showed a male predominancy. Postmyocarditic cardiomegaly was similar to chronic myocarditis but showed more hypertrophy, preexcitation waves and prominent negative T waves in electrocardiography and sudden death.

Adolescent↗
PubMed1989

[Differences in left ventricular shape between aortic and mitral regurgitation: an echocardiographic study].

The present study was designed to determine whether the long axis of the left ventricle is elongated in patients with aortic regurgitation. Among 445 patients with valvular disease who were followed in our hospital from April 1986 to February 1987, 14 with aortic regurgitation [AR: age: 46.1 (mean) +/- 17.6 (standard deviation) years] and 17 with mitral regurgitation (MR: age: 48.8 +/- 18.0 years) were selected for analysis. They all had optimal quality images in the apical view of the two-dimensional echocardiograms adequate for the evaluation and moderate to severe regurgitation at the time of Doppler examination. The control group consisted of 15 subjects without evidence of organic heart disease (age: 44.9 +/- 17.7 years). There was no difference in the mean duration of the clinical course between AR (14.9 years) and MR (13.4 years). The following measurements were made in the apical right anterior oblique view: Lo (long-axis distance of the outflow tract); from the left ventricular apex to the center of the aortic annulus, L (long-axis distance of the left ventricle); from the apex to the junctional point between the aortic and mitral valves, Li (long-axis distance of the inflow tract); from the apex to the center of the mitral valve ring, and d1, d2 and d3 (apical, middle and basal short axes of the left ventricle); the distances perpendicular to the each long axis at the levels of 1/4, 2/4 and 3/4 of the long axis. All data were corrected by means of the calibration scale, and compared as indices divided by the body surface area.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

A morphological study of the left bundle branch in the normal human heart.

To clarify the distribution pattern of the left bundle branch (LBB) in the human heart, the AV conduction system was studied in 13 autopsied hearts obtained from subjects aged 50 to 80 years. Vertical serial sections (7 micron) of the bundle of His and LBB were prepared and every 20th section was stained alternately with hematoxylin-eosin (HE) or by the elastica van Gieson (EVG) method and examined by light microscopy. Reconstruction was performed using a two-dimensional system in order to histologically differentiate the bundle cells from Purkinje cells. The LBB bifurcated into the anterior and posterior radiations and the cells in the septal portion were almost all Purkinje cells except in two cases showing a septal branch between the two radiations. The LBB usually branched widely from the bundle of His. An extremely anterior fascicle of the LBB was found in all cases. The distribution of the LBB at the top of the ventricular septum was divided into network and continuous types. Purkinje cells were present on both the atrial and apical sides of the two main radiations. It was suggested that these findings resulted from the fact that we morphologically differentiated the bundle cells from Purkinje cells by light microscopy.

Aged↗
PubMed1988

Three autopsied cases of postmyocarditic cardiomegaly. Comparison with dilated cardiomyopathy.

Three patients with clinically proven myocarditis who later developed dilated cardiomyopathy (DCM)-like features were studied pathologically at necropsy and compared with 42 other cases with DCM. The patients were an 18 year old female, a 20 year old male and a 28 year old male. They all had an upper respiratory tract infection as a prodromal symptom and then developed dyspnea on effort, electrocardiographic changes and cardiomegaly. In case 1, the antibody titers for Coxsackie B2 virus were elevated. In cases 1 and 3, myocardial biopsies revealed a mononuclear cell infiltrate. All 3 died of congestive heart failure. Histologically, layer-unit depletion of the myocardium (the myocardial damage and its sequelae (loss or minimal fibrosis) are restricted to certain layers), infiltration of mononuclear cells and moderate fibrosis were noted. In case 3, fibrosis and layer-unit depletion of the myocardium were mild. In our 42 DCM cases, the mean area of fibrosis was 40% in the fibrosis type, 15% in the nonfibrosis type and 30% in chronic myocarditis. In postmyocarditic cardiomegaly (PMC), the areas of fibrosis were 21.6%, 21.7% and 13.1% for the 3 cases. Mean cellularity indexes were 3.9% in PMC, 5.1% in the fibrosis type of DCM, 19.4% in the chronic myocarditis cases and 27% in the nonfibrosis type of DCM. With respect to fibrosis and interstitial cellularity, PMC most resembles the nonfibrosis type of DCM.

Adolescent↗
PubMed1988

[Morphological problems in cardiac hypertrophy].

Ventricular hypertrophy is categorized as (1) volume hypertrophy (eccentric hypertrophy or hypertrophy with dilatation), and (2) pressure hypertrophy (concentric hypertrophy or hypertrophy without dilatation). Hypertrophy per se is considered as a reaction to hemodynamic overload, both in occasions of excessive volume and of elevated pressure except in (idiopathic) cardiomyopathies. In patients with volume hypertrophy, some alteration of myocardial architecture is inevitable if the volume load exceeds a critical degree. Such alteration is characterized by deterioration of the median circular muscular layer of the ventricle resulting from over-stretching of the horizontally-coursing myocyte bundles. Hypertrophy of the inner oblique muscular layer of the left ventricle in cases with mitral regurgitation, and of the outer oblique muscular layer in cases with aortic regurgitation develops according to the changing configuration of the left ventricle; globular in the former, and elongated in the latter. In patients with pressure hypertrophy, there is some increase of the myocyte mass, with a disarrangement at the anterior triangle of the interventricular septum. The latter is physiologically situated at the anterior margin of the septum between the outer and median layers of both the ventricles. This seems to be a prelude to thickening of the septum and tends to hypertrophy of the free wall. A reduction in the deranged myocyte mass due to fibrosis or adiposis corresponds to arrest of the active hypertrophic process, and it may be the beginning of decompensation of cardiac function. Peculiar modes of dilatation and hypertrophy in cardiomyopathies have common denominators with those of known etiologies.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiomegaly↗
PubMed1988

[Coronary calcification in cinefluoroscopy: diagnosis of ischemic heart disease masquerading as dilated cardiomyopathy].

The feasibility of cinefluoroscopic grading of coronary calcification was tested for differential diagnosis of ischemic cardiomyopathy (IMD) and non-ischemic myocardial disease (N-IMD) simulating dilated cardiomyopathy (DCM). Twenty-seven patients with generalized hypokinesis of the left ventricle but without localized infarction or aneurysm on two-dimensional echocardiography were categorized as Group A of 17 cases examined by both cinefluoroscopy and coronary cineangiography (CAG); Group B, 10 examined only by noninvasive method because of severe congestive heart failure, old age or poor renal function. Cinefluoroscopy was recorded on 35 mm cinefilm for review using a 7 inch image intensifier, 2 to 3 mA and 90 to 100 kV, in the anteroposterior, right and left anterior oblique, and left lateral projections. We judged the degree of coronary calcification as Grade 1, calcification difficult to recognize; Grade 2, easily recognized; Grade 3, recognized in more than half of one coronary artery; and Grade 4, recognized in nearly the entire length of one coronary artery. To obtain the calcification score, the degree was multiplied by the number of calcified main coronary branches. IMD was defined as more than 75% decrease in the diameter of either the left main coronary artery or any other two major coronary vessels. I. The results obtained for group A were: 1. All six cases of IMD had coronary calcification. 2. The score of IMD was 21.2 +/- 8.1; that of N-IMD, 0.18 +/- 0.39. 3. The minimum IMD score was 10 without evidence of any calcification in the non-dominant right coronary artery. 4. Among three cases of DCM, two scored 1 and one scored 0. 5. The sensitivity and specificity of calcification for IMD were 100% and 81.8%, respectively. II. The following results were obtained in Group B, if IMD was defined as score more than 10. 1. The mean score of three IMD cases was 28 +/- 1.4, and the diagnosis was confirmed by subsequent CAG in two of them. 2. In none of the five N-IMD cases, calcification was recognized. The diagnosis of one case was confirmed by subsequent CAG. 3. The diagnosis was not confirmed in two cases who had score 3. These results indicate that calculated scores based on the severity of coronary artery calcification documented cinefluoroscopically can differentiate IMD from N-IMD both inexpensively and noninvasively.

Adult↗
PubMed1988

[Effect of hypertension on asymmetrical septal hypertrophy: an echocardiographic study].

The effect of hypertension on asymmetrical septal hypertrophy was studied by echocardiography to differentiate idiopathic asymmetrical septal hypertrophy (ASH) from ASH with hypertension. One hundred eight patients with ASH proven by echocardiography were categorized in two groups; 53 patients with hypertension (greater than 160 systolic, greater than 95 diastolic) (hypertensive group: HT) and 55 patients with normal blood pressure (normotensive group: NT). Septal hypertrophy was classified as mid-portion (M-type), diffuse (D-type), and basal (B-type) hypertrophy by the long-axis view, and also diffuse (I-type), anterolateral (II-type), anteroseptal (III-type), and anterior septal (IV-type) by the short-axis view, respectively. Endomyocardial biopsy and left ventriculography were performed in 50 patients (18 hypertensives and 32 normotensives). In the hypertensive group, 45%, 30%, and 25% of cases had diffuse, basal and mid-portion hypertrophy, respectively. There was no case in the basal hypertrophy whose biopsy findings were compatible with hypertrophic cardiomyopathy. In the normotensive group, 78% and 22% of patients had midportion and diffuse hypertrophy, respectively, but none of them had the basal hypertrophy. Type IV was seen in only six patients in the normotensive group.

Adult↗
PubMed1987

A morphological analysis of chronic myocarditis.

Eight patients with chronic myocarditis (CM), 2 showing postmyocarditis and 6 showing dilated heart with severe diffuse cell infiltration, were compared morphometrically with 27 patients with dilated cardiomyopathy (DCM, 8 with fibrosis type DCM and 19 with non-fibrosis type DCM) and 10 controls. Patients with CM had a mean age of 43.5 years (range, 17-75 years), a mean duration of clinical illness of 45.5 months, heart weight of 448 g, left ventricular wall thickness of 8 mm, number of myocyte layers of the stratum compactum layer of the left ventricle (Nf) of 125, myocyte size of 19.1 micron, and % area of fibrosis of 29.1%. The morphometric profile of patients with CM resembled that of patients with fibrosis type DCM; this appeared to be due primarily to a decrease in the number of myocardial cells and an increase in myocardial fibrosis.

Adolescent↗
PubMed1987

An experimental study of atherosclerosis as a sequela of coronary arteritis.

In order to examine the effect of corticosteroids on coronary atherogenesis in collagen diseases, an experimental study of serum sickness was performed. Forty-two rabbits were divided into four groups (Groups A-D). Group B, C and D rabbits received four intravenous injections of bovine serum albumin (250 mg/Kg) at 16-day intervals. Groups A, C and D rabbits were fed ad libitum cholesterol supplemented diet (1%) 16 days after the last injection. Group D rabbits received subdermal injections of prednisolone (1 mg/Kg) three times per week in the same period. After 124 days, all rabbits were sacrificed. Serum cholesterol and phospholipid increased in Group A, C and D rabbits. Group A rabbits showed intimal foam cell proliferation. Group B rabbits showed slight fibrous intimal thickening. The coronary arteries of Group C rabbits showed fatty-proliferative intimal thickening and an increase in the incidence of vascular lesions (13.9% of the coronary arteries as compared with 11.7% for Group A and 8.4% for Group B). The coronary lesions of Group D showed the same pattern as those of Group C, but the incidence of lesions was 6.0%. It was concluded that prednisolone did not augment immunologically induced atherosclerosis.

Animals↗
PubMed1987

Histopathological study of the papillary muscles and apex cordis of the hypertrophied left ventricle.

Hypertrophy of the papillary muscle and apex cordis of the left ventricle was studied histopathologically using 84 hearts obtained at autopsy. The hearts were divided into three groups: a hypertrophy group (heart weight more than 350 g); a borderline group (heart weight between 350 and 300 g) and a control group (heart weight less than 300 g). The size of the papillary muscle increased with increase in heart weight. Derangement of myocyte linings and fibrosis at the papillary muscle base became apparent with hypertrophy. In addition derangement and fibrosis extented from the internal to middle layers of the free wall with progressing hypertrophy. Derangement seemed to precede hypertrophy and fibrosis. A cluster of huge myocyte-like Purkinje's cells were associated with the center of the derangement. At the apex, criss-cross derangement developed from right and left side derangement with increasing hypertrophy. It is speculated that the focal derangement plays an important role in producing hypertrophy in response to mechanical stress with subsequent development of hypertrophy and fibrosis with some asymmetry.

Cardiomegaly↗