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Biomedical subjects

S Kimata

Publications and source records attributed to S Kimata.

At least 37 records · Page 2Linked to original sources
PubMed1991

Acute aortic dissection. A comparison between the results of medical and surgical treatments.

Over the last ten years 96 patients with aortic dissection were encountered in our Institute, of whom 51 had type A dissection, and 45 had type B dissection. In the patients with type A dissection the long-term survival rate was poor if they were not operated upon without delay, and the cause of death was usually rupture of the aneurysms. In the patients with acute type B dissection the surgical indication was limited and, generally speaking the long-term survival rate of the medically treated patients was more favorable.

Acute Disease↗
PubMed1991

Induction of diabetes by PolyI:C and anti-RT6.1 antibody treatment in DR-BB rats.

To determine whether environmental factors could affect the incidence of diabetes in RT6.1+ lymphocytes-depleted diabetes resistant (DR) BB rats, we tested polyinosinic-polycytidylic acid (Poly I:C), as an immune activator, in conjunction with anti-RT6.1 antibody in DR-BB rats which were bred in a specific pathogen free (SPF) condition. Diabetes was induced by the combined administration of poly I:C and anti-RT6.1 antibody. The use of poly I:C or anti-RT6.1 antibody alone did not cause diabetes. These results suggest that RT6.1+ T lymphocytes regulate autoimmune diabetes and that non-specific immune activation caused by environmental factors plays a key role in inducing diabetes in DR-BB rats.

Animals↗
PubMed1990

Long-term follow-up of medically treated patients with coronary artery disease--I. Incidence of major cardiac events and its risk factors in Japanese with coronary artery disease.

In the cooperative, multi-center trial, 491 medically treated patients with coronary artery disease were thoroughly assessed and followed for an average of 49 months. The rate of cardiac death and/or non-fatal myocardial infarction was 9.8%; 64% of cardiac events were fatal. Three factors, such as number of diseased coronary arteries, other diseased organs and the cardiothoracic ratio, contributed significantly to the evolution of cardiac events. The outcome of cardiac events in Japan in the period from 1973 to 1985 in patients with coronary artery disease was more favorable than those reported recently in the United States. The results of this study will serve as a control data base for further studies in Japan.

Adult↗
PubMed1990

Long-term follow-up of medically treated patients with coronary artery disease--II. Unstable angina pectoris, asymptomatic periods, and sudden unexpected cardiac events.

In order to clarify the incidence of unstable angina (UA), the rate of mutual transition to other forms of ischemic heart disease, and the short term prognosis of asymptomatic patients, we followed prospectively 421 medically treated patients after through assessment of coronary artery disease for an average of 43 months. Three hundred and two episodes of UA had occurred in 139 patients. Of these 14 patients experienced major cardiac events. Sixteen patients had sudden cardiac events with no prior UA. Two hundred and sixty-six patients had no episodes of UA nor cardiac events; of these, 97 patients were followed for more than 49 months. Those with both effort and rest UA had a much more higher incidence of unstable episodes and a higher average age than those with effort UA alone and those with rest UA alone. The average transition rate to the cardiac events by month of patients with UA, by markovian analysis, was higher than those of the asymptomatic or stable angina patient groups. When background factors are taken account, these transition rates might help the physicians in determining the treatment of patients with ischemic heart disease at a specific stage of state.

Adult↗
PubMed1990

Intravenous recombinant tissue-type plasminogen activator in patients with acute myocardial infarction--a report from the multicenter thrombolysis trial.

The efficacy and safety of intravenous infusion of human tissue-type plasminogen activator (rt-PA), developed in Japan (TD-2061), were investigated in 205 patients (154 men and 51 women) with evolving myocardial infarction (EMI). TD-2061 was given at a rate of 3.2 to 50 mg over 1 h after angiographic documentation of complete or subtotal (99%) occlusion. Nineteen patients were excluded as they did not meet the inclusion criteria. A total of 186 patients were divided into 6 groups according to the total dose given: Group I, 3.2 mg, 10 patients (pts); Group II, 6.4 mg, 15 pts; Group III, 12.8 mg, 15 pts; Group IV, 25.6 mg, 38 pts; Group V, 33.3 mg, 70 pts; Group VI, 50.0 mg, 38 pts. Ages ranged from 30 to 70 years (mean 60 +/- 1). Coronary angiography was done at 30 min and 1 h. In patients with TIMI grades 0 and 1, reperfusion was accomplished after 1 h in 22% of Group I, 50% of Group II, 64% of Group III, 70% of Group IV, 67% of Group V, and 74% of Group VI patients. Complications were hypotension, nausea and vomiting, bradycardia and bleeding at the puncture site. These findings suggest that clot-selective coronary thrombolysis can be induced in patients with EMI by means of human tissue-type plasminogen activator without concomitant induction of a severe systemic lytic state. The optimal dose for Japanese patients is considered to be 33.3-50.0 mg from the standpoint of reperfusion.

Adult↗
PubMed1989

Severity of cardiac failure from the standpoint of pulmonary circulation: studies centered on distribution of pulmonary perfusion.

In a normal man sitting upright, pulmonary perfusion is several times greater in the lower lung zone than in the upper zone. This pattern may sometimes be reversed in patients with cardiac disease. Tc99m-macro-aggregated albumin pulmonary perfusion images were computerized to isocounts area images (digital perfusion images; DPI). DPI were applied to various types of cardiac disease and patterns of DPI were divided into 4 classes according to amount of nonperfused pulmonary vascular bed. C-0; normal perfusion. C-1; decrease of nonperfused pulmonary vascular bed. C-2; disappearance of nonperfused pulmonary vascular bed. C-3; decrease of pulmonary vascular bed. In 71 patients with mitral stenosis relationships between pulmonary hemodynamics during exercise and distribution of pulmonary perfusion were studied, i.e. at rest (n = 71, mean pulmonary arterial pressure; 23 mmHg-cardiac index; 2.4 L/m) and during exercise C-0 (n = 13, 41 mmHg-5.4 L/m), C-1 (n = 17, 52 mmHg-5.2 L/m), C-2 (n = 27, 52 mmHg-4.5 L/m) and C-3 (n = 14, 65 mmHg-3.6 L/m) respectively. In patients with congestive heart failure cardiac status was classified to 4 classes according to ejection fraction and DPI. Patients with EF less than 30% and DPI more than C-2 showed high morbidity and mortality (two years mortality 47%; 27/40). Pulmonary venous pressure increases to maintain the cardiac index (Starling's law) in cases of decline in cardiac function or mitral stenosis. It was shown that increases in pulmonary venous pressure cause changes in distribution of pulmonary perfusion, which in turn works to depress the cardiac index. A decline in cardiac function and changes in the distribution of pulmonary perfusion coexist, mediated by pulmonary venous pressure and cardiac index. The distribution of pulmonary perfusion reflects the severity of cardiac failure itself, so by using DPI the severity of cardiac failure can be easily evaluated.

Blood Pressure↗
PubMed1988

Atrial natriuretic peptide distribution in fetal and failed adult human hearts.

The distributions of atrial natriuretic peptide (ANP) in human hearts during the developmental stage and in adult pathological states was examined with an antibody specific to human alpha-ANP. With immunoblotting and immunofluorescence methods, we found that a 17-kDa protein, which is a pro ANP, was expressed in human fetal ventricles, in which the numbers of myofibers containing ANP granules were more abundant in the subendocardial region than the subepicardial region. As determined by radioimmunoassay, the content of immunoreactive ANP (per milligram protein) in the developing heart was greatest in the left atrium and occurred decreasingly in the right atrium, right ventricle, and left ventricle, respectively. Because ANP content in the left ventricle declined during the progress of gestation in developing hearts and because it was very low, if ever detectable, in normal adult hearts, ventricular ANP expression appears to be developmentally regulated from the early gestational stage. However, it was reexpressed in the ventricles of patients who had suffered from severe congestive heart failure. In this situation, we found that the ventricular ANP expression was more marked in patients with dilated cardiomyopathy than in patients with severe valvular disease. Interestingly, in the ventricles of patients with dilated cardiomyopathy, ANP contents were higher in the left ventricular free wall than in the right ventricular free wall, although the left ventricular subendocardium contained more ANP than the subepicardium, showing a transmural gradient similar to that expressed in fetal ventricles. Thus, the expression of ANP in human ventricles is developmentally regulated from the early gestational stage, and even adult ventricular myofibers can synthesize ANP during severe congestive heart failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Surgical and medical treatments of true and dissecting aortic aneurysm in cases over 65 years old.

Ninety-one patients with true and dissecting aortic aneurysm were reviewed. They ranged in age from 65 to 87 years (mean 71 years). Forty-eight patients were diagnosed with abdominal aortic aneurysm, 21 patients with thoracic aortic aneurysm and 22 patients with dissecting aortic aneurysm. They were divided into 2 categories, surgical group and non-surgical, and the prognoses of the 2 groups were compared. The average age of surgically treated cases was significantly younger than that of non-surgical cases. This study suggests that elective operation should be considered for abdominal aortic aneurysms because of the high risk of late rupture. In older patients with thoracic aortic aneurysm, the prognosis was better in surgically treated patients than in those not treated. However, the surgical mortality rate of elective operation was high. The surgical mortality rate of older patients with dissecting aortic aneurysm was not satisfactory, and medical treatment which decreases blood pressure should be considered first. All patients classified as Stanford type A should be operated on if possible.

Age Factors↗
PubMed1988

[Utility of digital perfusion images of the lung in mitral stenosis: the pathophysiological significance of the distribution of pulmonary perfusion].

The relationship between pulmonary hemodynamics (cardiac index; CI and the mean pulmonary artery wedge pressure; mPw) and the redistribution of pulmonary perfusion were studied in 300 patients with mitral stenosis using computerized Tc99m-MAA perfusion images (digital perfusion images: DPI), which consisted of isocount areas. Various types of DPI were obtained and were classified in six grades according to patterns of 100-70% of the isocount area in the right anterior DPI, i.e. grade-0 (normal), grade-1 (increased perfusion in the upper zone), grade-2 (uniform distribution), grade-3 (disappearance of the basal hyperperfusion area), grade-4 (apical hyperperfusion area) and grade-5 (decrease of perfusion at the lower zone). The mPw was thought to be one of the factors determining distribution. Thus, it was not adequate to estimate the mPw from DPI. In patients with the mPw less than 20 mmHg, an increase in perfusion at the upper zone and disappearance of the basal hyperperfusion might be noted, however, the mPw more than 20 mmHg was necessary to cause an apical hyperperfusion area. The predictive values of grades 0 and 1 for the mPw less than 20 mmHg were 70% (54/77) and those of grades 4 and 5 for the mPw less than 20 mmHg and the mPw less than 25 mmHg were 86% (110/128) and 56% (71/128), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1988

Abnormal breathing patterns in patients with mitral stenosis: a possible compensatory role.

The breathing patterns of 37 patients with mitral stenosis were investigated in standing position by Konno-Mead analysis. Hemodynamic parameters were measured by cardiac catheterization, pulmonary function variables by pulmonary function testings and distribution of pulmonary perfusion by Tc-99m-MAA scintigraphy. Seventeen patients displayed rib cage dominant breathing patterns, and 6 patients displayed paradoxical breathing patterns, whereas 14 patients displayed normal breathing patterns. None of these patients exhibited an abdomen dominant breathing pattern. The patients with abnormal breathing patterns (rib cage dominant or paradoxical) displayed significantly higher values of pulmonary arterial pressure (p less than 0.01), capillary wedge pressure (p less than 0.01), total pulmonary vascular resistance (p less than 0.01) and mitral valve gradient (p less than 0.05) as well as smaller mitral valve area (p less than 0.05) and lower values of both in PaO2 (p less than 0.05) and diffusing capacity (p less than 0.05) than patients with normal breathing patterns. Abnormal distribution of pulmonary perfusion with hyperperfusion in the upper zone of the lung were found to be associated with the abnormal breathing patterns. Since rib cage dominant and paradoxical breathing patterns are known to increase ventilation in the upper zone of the lung, these abnormal breathing patterns may represent a compensatory mechanism serving to match ventilation and perfusion.

Adult↗
PubMed1987

The feasibility of beat-to-beat detection of His-Purkinje activity by finite element method.

A noninvasive method has been applied on human and canine subjects to observe beat-to-beat activity of the His-Purkinje system without using signal averaging. Recordings were performed with multiple Ag/AgCl electrodes, very low noise, high gain amplifiers and by analog filtering. The subjects were in a supine position during the recording. In order to reduce random noise inherent in the high-gain body surface recording, a finite element method (FEM) was applied to calculate His-Purkinje activity. The dimensional relationship between electrode sites, necessary for the calculation, was pre-estimated by x-ray computed tomographs of the subject. A prominent waveform was observed between the atrial and ventricular complexes and corresponded to His bundle activity which was simultaneously recorded by an intracardiac electrode (on every beat). It was, however, difficult to recognize the His-Purkinje activity during inhalation due to the thoracic electromyogram on some human subjects. This interference could theoretically be reduced by increasing the number of body surface electrodes used for this technique.

Animals↗
PubMed1987

Distribution of cardiac myosin isozymes in cardiomyopathy: immunohistochemical and gene analysis.

We characterized cardiac myosin isoforms by immunohistochemical approaches using monoclonal antibodies and demonstrated the existence of a distinctive type of cardiac myosin heavy chain which predominates in the fetal stage but is depressed during postnatal development. Furthermore, we showed that this type of cardiac myosin heavy chain was markedly expressed in patients with dilated cardiomyopathy. The results suggested that the pathologic process involved in dilated cardiomyopathy affects myocardial differentiation by the inhibition of the myosin gene switching that normally occurs during muscle maturation. However, we could not find any polymorphism in myosin gene in our population sample of dilated cardiomyopathy. The pathophysiological role of fetal type cardiac myosin expression in dilated cardiomyopathy will be clarified by the characterization of the myosin near future.

Adult↗