PubMed Health⌕ Search

Biomedical subjects

R Kikawada

Publications and source records attributed to R Kikawada.

At least 19 recordsLinked to original sources
PubMed1998

Doppler echocardiographic method to determine early and late diastolic filling volume separately. Validation and relationship between filling velocity and volume.

We devised a pulsed Doppler echocardiographic method of separately calculating early diastolic filling volume (EDFV) and late diastolic filling volume during atrial contraction (LDFV) and observed a relationship between diastolic filling volume and velocity in thirty patients with coronary artery disease. By analysing the transmitral flow velocity curve and mitral valve motion, EDFV and LDFV were measured on the basis of the equality of left ventricular inflow and outflow volumes. The Doppler-determined EDFV and LDFV correlated well with those obtained from the left ventricular filling curve produced by left ventriculography. Angiographic EDFV and LDFV were measured from the time (t)-volume (V) curve, using the t-dV/dt curve to define early and late diastolic phases. A good correlation was found between Doppler and angiographic EDFV (y = -3.0 + 1.0 x, r = 0.98, p = 0.0001, n = 20), Doppler and angiographic LDFV (y = 1.6 + 1.0 x, r = 0.86, p = 0.0001), and also between Doppler and angiographic EDFV/LDFV (y = 0.05 + 0.9 x, r = 0.93, p = 0.0001). EDFV and the peak early diastolic filling velocity were significantly correlated (E velocity; y = 25 + 0.51 x, r = 0.48, p = 0.0068), while LDFV and the peak late diastolic filling velocity during atrial contraction (A velocity) were not. Our results validate the method of calculating EDFV and LDFV separately and suggest that early diastole in the left ventricle has flow volume dependency, but that the late diastole filling velocity during atrial contraction may be regulated by other factors such as increased left atrial contraction.

Adult↗
PubMed1996

Effect of L-arginine on myoglobin-induced acute renal failure in the rabbit.

Because myoglobin is a potent inhibitor of nitric oxide (NO), we tested whether myoglobin infusion results in renal vasoconstriction and dysfunction, on which L-arginine, a source of NO, has a protective effect in sedated, nondehydrated, and nonacidotic rabbits. The infusion of myoglobin (375 mg/kg) resulted in a decrease in renal blood flow, an increase in renal vascular resistance, and a decrease in creatine clearance associated with a decrease in urinary excretory rate of nitrite/nitrate and guanosine 3',5'-cyclic monophosphate (cGMP). These values 1-2 h after the infusion were significantly different from baseline levels. Co-administration of L-arginine (150 mg/kg bolus followed by 150 mg.kg(-1).min(-1) reversed these changes significantly with attenuation of urinary excretory rate of nitrite/nitrate and cGMP. This study suggests that the myoglobin-induced renal vasoconstriction and dysfunction and protective effect of L-arginine on these outcomes could be mediated through the NO system.

Acute Kidney Injury↗
PubMed1996

Angiographic and coronary risk factor analyses of Japanese patients with ischemic heart disease before age 40--a multicenter cooperative study.

Coronary angiographic and risk factor (RF) characteristics were analyzed in 133 Japanese patients with ischemic heart disease (IHD) who were less than 40 years old and who had undergone coronary angiography (CAG) during the past 10 years at six university hospitals in the Tokyo area. We compared the coronary angiographic characteristics of the subject group with those of 216 controls with coronary sclerosis detected by CAG who were more than 40 years old (older control group) and the RF characteristics with those of 133 sex- and age-matched volunteers (younger control group). Sixty seven percent of the subjects (89 cases) were diagnosed as having myocardial infarction (MI) and 33% (44 cases) had angina pectoris (AP). Coronary artery disorders in this group consisted of 103 (77%) cases of coronary sclerosis, 20 (15%) cases of coronary spasm and 10 (8%) cases of miscellaneous diseases, eg, possible vasculitis with connective tissue disease, congenital anomalies, etc. The incidences of significant (> or = 75%) sclerotic narrowing in 0 vessels (31%) and 1 vessel (49%) in the subject group were significantly (p < 0.01) higher than those in the older control group, while the incidence of multivessel disease was significantly (p < 0.05) less in the subject group than in the older control group. The incidences of the following coronary risk factors were significantly (p < 0.05) higher in the subjects than in the younger controls: smoking (83% vs 35%), hypercholesteremia (44% vs 10%), obesity (31% vs 9%), hypertension (29% vs 3%), familial IHD (28% vs 7%) and diabetes mellitus (19% vs 2%). Thus, zero- or single-vessel disease predominated in the younger subject group and the prevalence of coronary risk factors was significantly higher in the subject.

Adult↗
PubMed1995

A case of right atrial myxoma--effect of large myxoma in the right atrium studied by M-mode and Doppler echocardiography.

Doppler profiles are rarely used to assess cardiac function that has been partially impaired by a sizeable myxoma in the right atrium or to evaluate the improvement caused by extirpation of the tumor. In a 54-year-old man with a large right atrial myxoma (6.5 x 5.5 x 4.0 cm) along with first-degree atrioventricular (AV) block, M-mode and pulsed Doppler echocardiography were used to evaluate the left ventricular systolic and diastolic function before and 1 month after surgical removal of the myxoma. End-diastolic left ventricular (LV) and left atrial diameters increased postsurgically from 47 to 51 mm and from 38 to 41 mm, respectively, while end-systolic LV remained unchanged. In the LV inflow pattern, peak early filling velocity (E) increased substantially (preoperative 31, postoperative 58 cm/sec), with no change in peak late filling velocity (A) (53 cm/sec), which gave a favorable E/A ratio (from 0.58 to 1.09). First-degree AV block resolved after tumor resection (PR interval: 0.23 vs 0.20 sec). Improved LV diastolic function associated with natural recovery from the myxoma was ascribed to the restoration of preload and recovery of systolic function. The results of this study show that removal of a large myxoma in the right atrium is important not only for preventing possible obstruction of the tricuspid orifice, eliminating pulmonary emboli, and maintaining systolic function, but also for restoring LV diastolic function.

Diastole↗
PubMed1995

Development of the conduction system in the rat heart as determined by Leu-7 (HNK-1) immunohistochemistry and computer graphics reconstruction.

BACKGROUND: The development of the heart conduction system is controversial. Our previous study demonstrated anti-Leu-7 antibody to cross-react with the cells of the conduction system in the embryonic rat heart. Thus, detailed analysis of the development of the conduction system was performed by immunohistochemical reaction with the use of the antibody. DESIGN: Horizontal serial sections of hearts obtained from embryonic and neonatal rats were treated for immunohistochemical reaction with anti-Leu-7 antibody, and three-dimensional images were reconstructed by computer graphics. Images were analyzed by superimposing the results on scanning electron micrographs. RESULTS: The development of the rat heart conduction system starts at 10 days and is completed by 18 days of gestation. The presence of three internodal tracts (INT1, -2, and -3) and two primordia of the atrioventricular node were confirmed in this process. INT1 and -3 pass through the septum spurium. INT2 follows the same route as the posterior internodal tract of James, but the other two INTs showed no correlation to previously described tracts. The sinuatrial node and INTs were found to be derivatives of the so-called S-A ring, and the bundle of His and bundle branches were found to be derived from the B-V ring. In this study, no immunoreactivity was observed in cells of the truncobulbar portion. CONCLUSIONS: Three internodal tracts and two atrioventricular node primordia were observed in the developing heart. The paths of the three internodal tracts showed intimate relationships with the internal structures of the heart. The developmental significance of the septum spurium, sinus septum, and venous valve was discussed.

Animals↗
PubMed1994

Rapid fall in blood myoglobin in massive rhabdomyolysis and acute renal failure.

OBJECTIVE: Myoglobin kinetics of removal from the circulation were studied in patients following massive rhabdomyolysis, to see if myoglobin remains for long in the circulation in the anuric state and if myoglobin elimination was affected by therapeutic manipulation such as haemofiltration or haemodialysis. DESIGN: Randomised and controlled study. SETTING: Intensive care unit of a tertiary care teaching hospital. PATIENTS: 26 patients of rhabdomyolysis whose serum myoglobin exceeded more than 500 nmol/l. Thirteen patients developed acute renal failure and underwent treatment with blood purification (Group HD). The remaining 13 patients did not require treatment with blood purification (control subjects, Group non-HD). INTERVENTIONS: In patients of group HD, twelve were treated with haemofiltration and/or haemodialysis. One was treated with peritoneal dialysis. The patient of group non-HD were treated with fluid infusion alone. MEASUREMENTS AND RESULTS: The serum concentrations of myoglobin were serially determined. The highest levels of myoglobin was 1641 +/- 484 nmol/l (mean +/- SEM) in the group non-HD and were 8957 +/- 2300 in the group HD. In the group non-HD, the blood myoglobin fell exponentially once myoglobin release into the circulation ceased. This was also noted in the group HD. The exponential decrease was observed even on the days when the patient passed little urine or treatment with blood purification was not performed. CONCLUSION: In patients with massive myoglobinaemia, the blood myoglobin rapidly fell independent of renal function or any therapeutic manipulation. The results indicate that extrarenal factors played a major role in disposing circulating myoglobin in such patients.

Acute Kidney Injury↗
PubMed1994

Clinico-pathological study of the role of infarct expansion in patients with cardiac rupture following acute myocardial infarction.

The purpose of this study was to clarify whether the infarct expansion with cardiac rupture following acute myocardial infarction pathomorphologically differed from expansion without rupture. Eighteen autopsied patients with rupture were classified into acute phase (time between the onset of myocardial infarction and death < or = 36 h) and subacute phase (> 36 h). These patients were compared with 25 patients with no rupture using new parameters of expansion: radius index, cavity index, expansion area index and thinning-dilatation index of the left ventricle. In the acute phase, each parameter was significantly higher in the ruptured group than in the non-ruptured group (radius index: 0.49 +/- 0.28 vs 0.14 +/- 0.16, p < 0.005, cavity index: 0.21 +/- 0.09 vs 0.08 +/- 0.06, p < 0.005, expansion area index: 0.75 +/- 0.25 vs 0.34 +/- 0.23, p < 0.001, thinning-dilatation index: 2.89 +/- 1.31 vs 1.53 +/- 0.52, p < 0.001). However, in the subacute phase there were no differences in these parameters between the two groups. These data suggest that in the acute phase, but not the subacute phase, the degree of expansion and the proportion of expansion to infarcted area are associated with rupture.

Aged↗
PubMed1994

Haemo-dialysis/-filtration using sodium bicarbonate depresses cardiac function in critically ill patients with acute renal failure.

The effect of sodium bicarbonate haemodialysis or haemofiltration on cardiac function was prospectively studied in 8 patients with acute renal failure. All of the patients exhibited consciousness disturbance and seven patients were on mechanical ventilation. All but one of the patients demonstrated moderate hyperlactataemia and seven patients were receiving vasoactive amine support. Arterial and mixed venous gas analysis and haemodynamic measurements were performed before and after haemodialysis/-filtration treatment. The buffer was changed in a randomised order between bicarbonate and acetate and 11 crossover studies were completed. After treatment with bicarbonate, the cardiac index and stroke index decreased significantly (4.0 +/- 0.3 to 3.4 +/- 0.4 L/ min/m2, p < 0.05 and 39.6 +/- 2.5 to 32.9 +/- 1.8 L/m2, p < 0.05), whereas no significant changes were observed in cardiac index or stroke index after treatment with acetate. Therefore, the post-dialytic percent changes of cardiac index, stroke index and left ventricular stroke work index were significantly decreased after bicarbonate sessions, as compared to after acetate sessions. Haemo-dialysis/-filtration using sodium bicarbonate can depress cardiac function in critically ill patients on mechanical ventilation with disturbed consciousness, and in those who are receiving vasoactive amine support due to uncompromised haemodynamics associated with hyperlactataemia.

Acetates↗
PubMed1994

Massive rhabdomyolysis associated with influenza A infection.

A 20-year-old male with massive rhabdomyolysis associated with a high fever and acute renal failure is reported. Influenza A infection was confirmed serologically. Myoglobin kinetics was studied in this case. Blood myoglobin fell exponentially independent of renal function or therapeutic modality such as hemodialysis/filtration, once myoglobin release into the circulation ceased. The finding suggested that catabolic steps of myoglobin take place extrarenally in patients with massive rhabdomyolysis and acute renal failure.

Acute Kidney Injury↗
PubMed1994

[Clinical characteristics of hemolytic uremic syndrome/thrombotic thrombocytopenic purpura (HUS/TTP) in adult].

Hemolytic uremic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP) were originally described as separate disease entities. Recently, HUS and TTP have been considered a single disease, because of the identical microangiopathic lesion. In the present study, we investigated the clinical and histological characteristics of HUS/TTP. Eleven patients with a definite diagnosis of HUS/TTP were found from a cohort of adult patients who were admitted to Kitasato University Hospital in the past two decades. Their clinical and histological characteristics were retrospectively analyzed. All of the 11 patients with HUS/TTP were sporadic and non-diarrheal cases with a mean age of 49 years +/- 10. Preceding episodes of flu-like syndrome and the administration of mitomycin C were observed in 3 and 5 patients, respectively. On admission, two of 10 patients with renal dysfunction required dialysis treatment, while none developed nephrotic syndrome. Six patients showed CNS manifestation, such as consciousness disturbance and convulsion. Three patients with severe hypertension did not show consciousness disturbance. As for the final outcome, 6 patients recovered and the remaining 5 died. Two died after 60 hospital days. In the histopathological investigation, renal biopsy specimen showed narrowing of the capillary loops in the glomeruli due to swelling of the endothelial cells, double contour of the glomerular basement membrane, or mesangial cell necrosis and sclerosis. In the autopsy specimen, internal organ infarction with fibrin thrombi in small arteries was observed in multiple organs, such as brain, kidneys, hearts, lungs, jejunum, liver, pancreas, adrenal glands and pituitary gland. A circumferential myocardial infarction with hyaline thrombi in the medial layer of myocardium was characteristic of HUS/TTP. In conclusion, microangiopathic lesions with infarction spread widely throughout various organs in HUS/TTP. Involvement of internal organs, not to mention kidneys and brain, is lethal and their prognosis remains poor.

Adult↗
PubMed1993

Immunohistochemical study on the development of the rat heart conduction system using anti-Leu-7 antibody.

Morphological aspects of the heart conduction system have been studied by various histochemical markers. However, the actual presence of markers in the conduction system and its developmental mode remain controversial. We have shown the anti-Leu-7 antibody to cross-react with cells of the rat embryonic heart conduction system by an immuno-electron microscopic study. A comparison was thus made between the results of Leu-7 immunohistochemistry and those by other markers previously used for studying the development of the conduction system. As a result, Leu-7 immunoreactivity proved the most reliable marker for studying the conduction system of the developing rat heart. Examination of the developmental mode of a rat conduction system was facilitated with the use of this marker. The immunoreactivity for Leu-7 initially appeared in the anterior wall of the bulboventricular region at 10 days of development. The development of three internodal tracts and two atrioventricular nodes was demonstrated in the following stage. These primordial atrioventricular nodes, one of which connects to a bundle of His, fused to form a single distinctive node followed by completion of the conduction system in the 18 day fetus.

Acetylcholinesterase↗
PubMed1993

[Clinico-pathological study of the mechanism of initiation and progression of right ventricular infarction].

To clarify the mechanism of initiation and progression of right ventricular myocardial infarction, 35 cases were examined among 236 cases of consecutively autopsied hearts. Twenty-six (52%) of 50 cases with posterior left ventricular infarction showed right ventricular infarction, and no statistical differences were observed in the age, gender, and number of impaired vessels among patients with and without right ventricular infarction. However, more proximal occlusion or more extensive thrombi in the right coronary artery did play a very important role in the genesis of the infarction and its progression. Right ventricular dilatation was frequently associated, probably resulted from the functional disorder of contraction and relaxation of the myocardium. Unusual asynchronous ischemia was observed in the right ventricle concomitantly with posterior left ventricular infarction, suggesting the presence of a protective mechanism against ischemia by the abundant collateral circulation of the right ventricle. In conclusion, right ventricular infarction occurs only with the cease of collateral circulation due to proximal occlusion and the presence of long thrombi in the right coronary artery.

Adult↗
PubMed1993

[A case of right atrial myxoma: M-mode and pulsed-Doppler echocardiographic findings before and after operation].

There are some reports concerning operations of right atrial myxoma. But precise effect on systemic hemodynamics before and after operation of right atrial myxoma has not been reported. We studied hemodynamics of a 54 year-old male with right atrial myxoma before and after removal of myxoma by M-mode and two-dimensional echocardiography. He was admitted to our hospital because of dyspnea on effort and orthostatic dizziness. On two-dimensional echocardiography the apical four chamber view showed an abnormal huge mass echo with cystic change (6.9 x 4.4 cm) moving between the right atrium and the orifice of tricuspid valve. From this finding emergent operation was undertaken with the possible diagnosis of right atrial myxoma, and the mass was found to be a benign myxoma histopathologically originating from the right side of atrial septum. Left ventricular dimensions (Dd, Ds) and the dimension of left atrial chamber were enlarged after the operation by M-mode echocardiography. Among the left ventricular inflow parameters, rapid filling peak velocity (E) increased with no change in presystolic peak velocity (A) and A/E improved from 1.63 to 0.95. This improvement of left ventricular diastolic function was supposed to be induced through the increased preload. After the operation his manifestations of dyspnea and dizziness have disappeared. It should be emphasized that an increase in preload after the removal of right atrial myxoma is very important to keep left ventricular diastolic and systolic function.

Echocardiography↗
PubMed1992

Exercise performance in essential hypertension with special reference to blood pressure response and left ventricular hypertrophy.

Exercise performance in essential hypertension (EH) and its relations to blood pressure (BP) response and left ventricular hypertrophy (LVH) were studied. Twenty-three patients with mild to moderate EH and 12 controls underwent symptom-limited (except BP elevation more than 250 mm Hg) ergometer exercise. Exercise performance was evaluated by the oxygen uptake (VO2/kg) at anaerobic threshold (AT) and at peak exercise (Peak). Left ventricular geometry and function, and left ventricular mass index (LVMI) were measured using echocardiography. The endpoints of 12 patients (group A) and controls were fatigue. The endpoints of 11 patients (group B) were BP elevation. Though both group A and group B had concentric hypertrophy, group B showed severe LVH compared to group A and controls. The VO2/kg at AT or at Peak was not different among the three groups. Neither BP response or LVMI correlated with exercise performance in EH. We conclude that exercise performance is not disturbed in EH; that BP response to exercise is not related to exercise performance in EH; and that concentric LVH may be a compensatory mechanism to maintain exercise capacity against exaggerated BP elevation in EH.

Adult↗
PubMed1992

[Comparison of treadmill exercise, handgrip, and cold-pressor tests: with particular reference to the effects on hemodynamics, respiratory gas exchange, and sympathetic nervous activity].

The treadmill test (TM), handgrip test (HG) and cold-pressor test (CP) are now frequently used clinically for multiple purposes. However, gas exchange analysis has not been a common procedure during HG. In particular, during CP, it has not been previously reported. Relationships between these 3 tests and blood pressure, heart rate (HR), respiratory gas exchange and the sympathetic nervous activity of normal subjects have not been reported, either. This study was undertaken to clarify these points. Symptom-limited TM was performed in 11 normal male subjects with a mean age of 45 +/- 8 yrs according to the Bruce protocol, with the HG using the weight-sustaining method (equal weight of 50% maximal voluntary contraction) for 3 min, and CP for 2 min. Systolic and diastolic blood pressures (Ps, Pd) were recorded; HR was measured every 30 sec, and gas exchange variables, such as oxygen uptake (VO2) and carbon dioxide production, were documented every 10 sec using an aereomonitor AE-280 (Minato Medical Science Co). In 10 of 11 subjects, concentrations of plasma noradrenaline (PNA) and plasma adrenaline (PAD) were measured at rest and at the times of peak values of the 3 tests. The peak values of Ps and HR were much higher during TM than during HG and CP (p < 0.01), while the peak values of Pd during HG and CP were higher than during TM (p < 0.01). The VO2 increased significantly for all of the 3 tests (TM: +781%, HG: +65%, CP: +20%), with the increment being the greatest during TM. Both PNA and PAD increased significantly for the 3 tests, with the increments of PNA and PAD being the greatest during TM. The percent change in PAD was more prominent during HG and CP than during TM. This tendency was not as clear for PNA as for PAD. There was no correlation of delta Ps and delta Pd between the 3 tests, but values of delta HR correlated partially. No significant correlations of peak VO2 were observed between the 3 tests. The peak PNA correlated between HG and CP (r = 0.77, p < 0.01), and the peak PAD correlated between TM and CP (r = 0.67, p < 0.05). In summary, numerous differences in hemodynamic and respiratory responses and in sympathetic nervous activation were observed in the 3 tests. When the 3 tests are undertaken, careful attention should be paid for their characteristics, discrepancies and limitations.

Adult↗