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Biomedical subjects

H Kanemitsu

Publications and source records attributed to H Kanemitsu.

52 records · Page 3Linked to original sources
PubMed1989

Cerebral uric acid, xanthine, and hypoxanthine after ischemia: the effect of allopurinol.

The existence of uric acid in mammalian brain was recently reported, but it has not yet become a consensus. The mammalian brain has been thought to lack xanthine oxidase, which catalyzes hypoxanthine to xanthine and xanthine to uric acid as the last steps of ATP degradation in other tissue. Using high-performance liquid chromatography, we performed assays for hypoxanthine, xanthine, and uric acid in rat brain after cerebral ischemia. It was confirmed that all three substances showed significant augmentation in the removed brains and that the chronological order of those increases corresponded to the order in the metabolic pathway. Allopurinol, a specific inhibitor of xanthine oxidase, significantly suppressed the increases in uric acid and xanthine, and a compensatory accumulation of hypoxanthine was observed. From these results, it was concluded that uric acid does exist in the brain, increases after ischemia, and is possibly the end product of purine degradation in the brain. Furthermore, it is suggested that xanthine oxidase exists in the brain and catalyzes the reaction from hypoxanthine to xanthine and then to uric acid. These reactions catalyzed by xanthine oxidase are considered to be a source of free radicals and may play important roles in the pathogenesis of cerebral ischemic injury.

Allopurinol↗
PubMed1989

[Changes in xanthine and uric acid in rat brain after middle cerebral artery occlusion].

Xanthine and uric acid, products of purine metabolism, were measured by reversed-phase high-performance liquid chromatography (HPLC) with electrochemical detection in rat forebrain following focal cerebral ischemia. Focal cerebral ischemia was induced in the rat by permanent occlusion of the left middle cerebral artery (MCA). Sprague-Dawley rats were anesthetized with halothane inhalation and left MCA was occluded via trans-retro-orbital approach. Normal and sham-operated rats were used as control animals. The animals were decapitated 2 (MCA = 5, Sham = 5), 4 (MCA = 7, Sham = 6), 8 (MCA = 5, Sham = 5), and 16 (MCA = 6, Sham = 6) hours or 1 (MCA = 5, Sham = 5), 2 (MCA = 6, Sham = 6), 7 (MCA = 7, Sham = 6), 14 (MCA = 6, Sham = 5), and 28 (MCA = 7, Sham = 5) days after the operation. The brains were removed and divided into right and left hemisphere. Each hemisphere was homogenized and centrifuged. The supernates were filtered with membrane filter. An aliquot of the filtrate was used for measurement of xanthine and uric acid in both of the ischemic and contralateral hemisphere by a HPLC system. In the normal group, xanthine and uric acid in the brain was 12.4 +/- 0.4 and 2.2 +/- 0.1 nmol/g tissue (mean +/- SEM), respectively. In the ischemic hemisphere, xanthine increased up to 57.7 +/- 5.2 nmol/g tissue 2 hours after MCA occlusion and reached a maximum value of 59.42 +/- 4.91 nmol/g tissue 4 hours following the induction of ischemia. Xanthine level was still high 8 hours after ischemia and then rapidly decreased to the normal value at day 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Xanthine and uric acid levels in rat brain following focal ischemia.

Changes of the xanthine and uric acid (UA) levels in rat forebrain following focal cerebral ischemia were studied by reversed-phase HPLC with electrochemical detection. Focal ischemia was induced by occluding the left middle cerebral artery in the rat. The xanthine level in the normal group was 11.50 nmol/g tissue. In the ischemic group, the xanthine concentration in the ischemic hemisphere progressively increased after occlusion and reached a maximum value of 59.42 nmol/g tissue 4 h after operation. The UA level in the normal group was 2.20 nmol/g tissue, whereas in the ischemic group the UA concentration in the ischemic hemisphere gradually increased after occlusion, reaching a value of 38.53 nmol/g tissue 24 h after ischemia. The concentration of UA remained elevated in the ischemic hemisphere until 48 h after occlusion, and reached a maximum value of 38.98 nmol/g tissue. The xanthine and UA levels in the contralateral hemisphere remained unchanged. The xanthine and UA concentrations in the sham-operated group did not show a significant increase after operation. The time course of xanthine and UA levels suggests that in ischemic forebrain UA is formed from xanthine as a product of purine metabolism.

Animals↗
PubMed1986

Changes of uric acid level in rat brain after focal ischemia.

Changes of uric acid level in rat cerebral hemisphere after left middle cerebral artery (MCA) occlusion were studied by reversed-phase HPLC with electrochemical detection. Uric acid level in the normal group was 2.98 nmol/g tissue. Uric acid concentration of the left hemisphere in the left MCA-occluded group progressively increased after occlusion, and reached a maximum value of 67.26 nmol/g tissue 24 h after ischemia. Uric acid levels in the right hemisphere remained unchanged. Uric acid concentration of the left hemisphere in sham-operated group was 9.29 nmol/g tissue 24 h after the operation.

Animals↗
PubMed1984

[Non-invasive estimates of hemodynamics in normal pregnancy].

Pregnancy provides excellent opportunities for observing the hemodynamic alterations in cardiac function occurring during the physiologic stress imposed on the normal myocardium. Hemodynamically, the most important change in the maternal circulation during pregnancy is an increase in the circulating blood volume and cardiac output. In the average woman, the cardiac output at rest rises 30-50% above the normal non-gestational resting value. Echocardiography was performed for 25 normal pregnant women, ranging in age from 21 to 36 years (mean age of 28.7 years). Echocardiography was performed periodically through out pregnancy, at the gestational ages of the 10th, 24th, 32nd, 36th, and the 3rd postpartal weeks. Tracings were obtained in the left lateral and supine positions. All pregnancies were uncomplicated, and there was no twin pregnancy. The heart rate increased throughout gestation. However, the systolic and diastolic blood pressures did not change significantly throughout pregnancy. End-diastolic left ventricular dimension (LVDd) increased throughout gestation, with the peak at the 36th week of gestation. Left atrial dimension (LAD) and mVCF increased at the 36th week of gestation. Throughout gestation, the ejection fraction (EF) showed no significant change. There were no measurable differences in the cardiac size and function in the left lateral and supine positions. Increased LVDd and LAD throughout gestation were thought the reflexion of the increased blood volume and venous return which had its peak in the 36th week of gestation. The slightly larger cardiac size and end-diastolic volume seemed to induce the increased myocardial fiber stretch and, in turn, the increased mVCF. Our results indicated that chronic volume overload with increased circulating blood volume occurs in normal pregnancy, resulting in the large cardiac size and increased contractility of myocardial fiber.

Adult↗
PubMed1981

Echocardiographic study of the Duchenne type of progressive muscular dystrophy.

The present study was undertaken in an attempt to clarify whether or not any relationship exists between the echocardiographic indices of cardiac function and the severity of progressive muscular dystrophy of the Duchenne type (PMD). A total of 75 patients with PMD was used for analysis. Among the echocardiographic parameters measured in the study, the maximal diastolic endocardial velocity (DEVM) and ejection fraction (EF) revealed a gradual decreasing tendency with increasing severity of the disorder. It can be concluded therefore that DEVM and EF may represent useful indices in the assessment of cardiac function in PMD.

Adolescent↗
PubMed1981

Primary hemangiopericytoma of the heart. A case report.

Hemangiopericytoma (HP) represents a rare cellular vascular tumor. The present report of primary HP of the heart in a 53-year-old Japanese male is the first of its kind. Most of the tumor masses were removed, but masses tightly adhering to both the pericardium and the epicardium were not excised because of profuse bleeding. The patient has remained free of complaints for 10 months post-operatively. Non-invasive methods including a chest X-ray, echocardiogram, and thallium-201 myocardial imaging were found to be useful adjuncts of the diagnosis of cardiac tumor.

Heart Neoplasms↗
PubMed1981

[Detection of aortic valve prolapse by cross-sectional echocardiography (author's transl)].

Echocardiography has been widely used for a detection of mitral and tricuspid valve prolapse. However, no extensive study has been made for a recognition of aortic valve prolapse. In this study, an echocardiographic search for aortic valve prolapse was attempted on 1700 consecutive cases at our laboratory including 70 cases with aortic regurgitation and 30 with mitral valve prolapse. Criteria of aortic valve prolapse by cross-sectional echocardiography were as follows: (1) eccentric coaptation point of aortic valve cusps, (2) asymmetric enlargement of the aortic valve cusp, and (3) downward displacement of the cusps. Using the above-mentioned criteria, five cases were recognized as having aortic valve prolapse, and it was divided into the following three morphological patterns: (1) prolapse of the right coronary cusp (1 case), (2) prolapse of the left coronary cusp (1) case, and (3) prolapse of the noncoronary cusp (3 cases). All 5 cases showed apparent aortic regurgitation, while none of these cases had any evidence of mitral valve prolapse. From the present observations, it might be suggestive that aortic valve prolapse is one of the common causes of aortic regurgitation. Elucidation of a spectrum of aortic valve prolapse should wait for a further extensive study.

Aged↗
PubMed1981

[Heart sounds and heart murmurs in progressive muscular dystrophy of Duchenne type (author's transl)].

Phonocardiographic and echocardiographic investigation was performed in patients with progressive muscular dystrophy of Duchenne type (PMD). The clinical materials consisted of 90 patients with PMD (aged 8 to 21 yrs, a mean of 14.5), and 90 normal subjects (aged 6 to 19 yrs, a mean of 11.7). The patients with PMD were classified into 8 stages from the mildest, S(1), to the severest, S(8), according to Swinyard-Deaver' criteria. In the 90 normal subjects the diminished first heart sound was noted in 12 cases (13.3%), presystolic murmurs in 4 cases (4.4%), and diastolic rumbles in 9 cases (10%), whereas, in the patients with PMD the diminished first heart sound was noted in 47 cases (52.2%), presystolic murmurs in 41 cases (45.6%), and diastolic rumbles in 44 cases (48.9%). There was a significant difference in the incidence of the above-mentioned three phonocardiographic findings between the PMD patients and the normal subjects. But there was no significant difference in the incidence of a systolic click between these two groups. The incidence of the diminished first heart sound increased with the progress of Swinyard-Deaver' classification. A presystolic murmur was observed with the highest incidence in the stage of S(8). The incidence of a rumble was also augmented with increasing severity of the disorder from the stages of S(1) to S(7), but decreased in S(8). Another attenpt was made to relate the phonocardiographic findings to those of the echocardiogram. In the cases with anterior mitral leaflet fluttering, there were diastolic rumble in 69% whereas 16.7% of the patients without anterior mitral leaflet fluttering had diastolic rumbles. In two-dimensional echocardiography, the anterior and posterior mitral leaflets looked like pennants fluttering in the wind. All these observations positively indicate that anterior mitral leaflet fluttering was closely associated with the genesis of rumbles. Consequently, it can be concluded that the diminished first heart sound, presystolic murmurs and diastolic rumbles might be useful clinical signs in the assessment of the myocardial involvement in PMD.

Adolescent↗
PubMed1981

[Detection of left ventricular thrombi by echotomography and computed tomography (author's transl)].

Left ventricular (LV) thrombi are rarely recognized during life, though they are not infrequent at the post-mortem examination of patients succumbed to valvular disease, acute myocardial infarction, and cardiomyopathy. We presented five cases in which LV thrombi were detected by cross-sectional echocardiography (CSE) and confirmed by computed tomography. The main purpose of this study was to compare the echocardiographic findings of the LV thrombi with the manifestations of the LV thrombi on the computed tomograms, with a hope to augment the clinical utility of CSE in the detection of LV thrombi. CSE was recorded from the apical and four-chamber views in addition to the conventional approach. A computed tomographic whole-body scanner which utilized a continuously rotating gantry and pulsed anode with X-ray radiation collimated to form a thin fan-shaped beam was used. A complete section scan was performed in 3 seconds. Sustained enhancement was obtained with a rapid intravenous infusion of 30% meglumine iothalanate. Most of the LV thrombi showed an abnormal echo with irregular borders and/or a mobile mass echo at the apex by CSE. Computed tomographic findings suggestive of LV thrombi appeared as a defect, which was apparently different in quality from the surrounding myocardium or valvular apparatus. These findings were quite consistent with those of CSE with respect to the number and the location of the LV thrombi. Consequently, it may be concluded that CSE is a useful adjunct in the detection of LV thrombi and an additional use of computed tomograph will certainly open up a promising way to make the secure diagnosis of LV thrombi.

Aged↗
PubMedDate not supplied

Massive pulmonary hemorrhage in polyarteritis nodosa (PN); report of a case.

We report a case of massive pulmonary hemorrhage which emerged in the course of polyarteritis nodosa (PN). Pulmonary hemorrhage was the major manifestation which determined the mortality of this patient, though severe renal failure concurrently developed. The diagnosis of PN should be considered in all cases of pulmonary hemorrhage coexisting with renal failure. As pulmonary hemorrhage can be life-threatening, early diagnosis is essential for the prompt start of adequate therapy.

Acute Kidney Injury↗