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Biomedical subjects

R Kikawada

Publications and source records attributed to R Kikawada.

At least 55 records · Page 3Linked to original sources
PubMed1988

Detection of leukotriene B4 in cardiac tissue and its role in infarct extension through leucocyte migration.

The main left coronary artery of rats was ligated near its origin under light ether anaesthesia and the infarction observed for 48 h. The ischaemic area was determined after an intravenous injection of pontamine sky blue dye 1 h before induction of cardiac arrest with potassium chloride. The unstained area (true ischaemic area) decreased with time to 27.1% of the left ventricle at 48 h, whereas the intensely stained area between the normal and the true ischaemic areas increased with time, suggesting that blood was flowing to the border from the normal surrounding tissue. The infarcted area, identified by its lack of triphenyltetrazolium chloride staining, became evident after 3 h and stabilised at 12 h (42% of left ventricle). The polymorphonuclear leucocyte counts in the hearts, differentiated by staining of their chloroacetate esterase, increased gradually up to 5500 cells per section at 24 h. The leukotriene B4 concentration, determined by radioimmunoassay after freezing of the beating heart in liquid nitrogen, increased to eight times that of the sham operated hearts and peaked at 8 h (9.4(0.6) ng per heart, mean(SEM) n = 5) before the leucocyte counts reached their maximum. A single oral dose of a selective 5-lipoxygenase inhibitor (AA-861, 80 mg.kg-1, 1 h before ligation) lowered the leukotriene B4 concentration to that of the sham operated hearts and decreased the leucocyte count by 49.4% and 41.2% at 12 and 24 h respectively. The inhibitor also reduced the infarct size at 48 h by 34.4%. It was concluded that leukotriene B4, generated in ischaemic cardiac tissue, may increase infarct size through migration of polymorphonuclear leucocytes.

Animals↗
PubMed1988

Orthostatic hypertension due to coexistence of renal fibromuscular dysplasia and nephroptosis.

A 42-year-old woman presented with orthostatic hypertension. Increased plasma renin activity was noted and blood pressure rose gradually with standing. Selective renal arteriography indicated narrowing of the distal portion of the right renal artery and poststenotic dilatation and signs of arterial stenosis due to fibromuscular dysplasia. Greater arterial narrowing resulted from tortion due to nephroptosis brought about by excessive renin secretion. Thus, both renal arterial stenosis and nephroptosis were considered responsible for the present orthostatic hypertension. Percutaneous transluminal renal angioplasty was found very effective for normalizing standing blood pressure and renal blood flow.

Adult↗
PubMed1988

Antihypertensive efficacy and safety of urapidil, alone or in combination with beta-blockers, in patients with phaeochromocytoma.

The clinical efficacy and safety of urapidil, used alone or in conjunction with beta-blockers, were evaluated in 14 patients with phaeochromocytoma. Following a 1-week placebo run-in period, the patients were treated with sustained-release capsules of urapidil, initially 30 mg twice a day, followed by dose adjustment within 30-270 mg (mean +/- s.d. 144 +/- 73) per day for 7-29 days (21 +/- 8 days). In six patients, beta-blockers were added to control associated tachycardia. Blood pressure and pulse rate were successfully controlled in 11/14 patients (78.6%) during the therapy. Both the frequency and the severity of hypertensive paroxysms were clearly reduced in 7/8 patients, who showed frequent paroxysms of hypertension during placebo treatment. A variety of subjective symptoms observed in 13 patients during placebo treatment improved during drug therapy in nine patients (69.2%). Side effects occurred in five patients but were minor and well tolerated except in one patient, who was withdrawn from urapidil monotherapy due to facial oedema and finger stiffness which persisted even after reducing the daily dose from 306 to 270 mg. Overall, in terms of antihypertensive effectiveness, improvement in subjective symptoms and the safety profile, urapidil was considered very useful in four patients (28.6%), useful in six (42.9%), slightly useful in three and useless in one. Urapidil therefore appears to be a worthwhile agent in the treatment of patients with phaeochromocytoma.

Adrenal Gland Neoplasms↗
PubMed1988

[Pulmonary to systemic flow ratios in patients with ventricular septal defect: estimation by transmitral flow velocity].

Using pulsed Doppler echocardiography, left ventricular inflow flow volume (LVIV) and outflow flow volume (LVOV) were noninvasively determined, and the ratio of pulmonary to systemic flow (Qp/Qs) was evaluated as the ratio of LVIV to LVOV (LVIV/LVOV). Thirty patients with ventricular septal defect (VSD) were studied, and 47 cardiac patients without aortic or mitral valve disease or intracardiac shunt served as controls. LVOV was derived from the left ventricular ejection flow velocity and the outflow tract diameter immediately proximal to the aortic valve ring. LVIV was derived from the transmitral flow velocity and the M-mode tracing of mitral valve motion. Doppler-determined cardiac outputs (COin and COout) were calculated as the products of LVIV or LVOV as and heart rates. Cardiac outputs were also determined by the dye dilution method (COdye) references for comparison with Doppler-determined cardiac outputs. There were good correlations between COdye and COin (y = 1.18x-243, r = 0.85, p less than 0.005, SEE = 1026 ml/min) and between COdye and COout (y = 1.16x-323, r = 0.90, p less than 0.005, SEE = 639 ml/min). LVIV and LVOV correlated well in the controls (y = 0.95x + 5.3, r = 0.94, p less than 0.005, SEE = 6.6 ml). LVIV/LVOV was 0.97 +/- 0.1 (mean +/- SD) in the controls; whereas LVIV/LVOV (1.86 +/- 0.90) was significantly higher in patients with VSD (p less than 0.01) and this ratio correlated well with Qp/Qs by an oximetry (r = 0.98, SEE = 0.20, n = 14), including patients associated with pulmonary regurgitation. These findings indicate that our method permits determination of LVIV with a high degree of accuracy and that the Doppler-determined LVIV/LVOV is clinically useful to evaluate accurately the magnitude of shunt flows in patients with VSD.

Adolescent↗
PubMed1987

[Differences in hemodynamic responses to dynamic exercise between borderline and sustained hypertension].

To observe the effects of anatomical distribution of left ventricular hypertrophy (LVH) and the differences in blood pressure on cardiac function, borderline hypertensives (group A) and mild or moderate sustained hypertensives (group B) were studied at rest and during dynamic exercise and their results were compared with those of normal controls (group C). LVH was estimated by M-mode echocardiography, and cardiac function was assessed by radionuclide (RI) first pass and multigate methods. In each subjects, 0.5 watt/kg and 1.0 watt/kg loads of ergometer exercise were administered for 16 min in the supine position. The main results were as follows: 1. In borderline hypertension, there was significant hypertrophy of the interventricular septum, and the left ventricular mass index was greater than that in normal controls. 2. The cardiac index in borderline hypertension did not differ from that of normal controls, but that of sustained hypertension was significantly reduced. 3. Significant positive correlations were observed between blood pressure and the left ventricular mass index at rest and during exercise. 4. No difference in left ventricular ejection fraction (LVEF) at rest was observed among the three groups, but that in sustained hypertension during exercise was markedly less than that of the other groups. LVEF at 1.0 watt/kg load and delta LVEF correlated inversely with the left ventricular mass index. 5. Left ventricular end-systolic volume determined by an RI count method decreased significantly during exercise in normals and borderline hypertension, while that in sustained hypertension was not reduced during exercise. Accordingly, cardiac function in the latter group was judged to be impaired. 6. In borderline hypertension, regional LVEF in the septal portion was slightly reduced at rest and during exercise. This reduction might have been caused by an imbalance of hypertrophy between the septal and free wall portions. In sustained hypertension, regional septal LVEF was maintained at rest, but was markedly less during exercise as compared with the other groups. Regional LVEF in the free wall portion was similar in degree to that of LVEF at rest and during exercise in the three groups. 7. Though the peak filling rate (PFR) in borderline hypertension did not differ from that in controls, that of sustained hypertension was significantly reduced at rest and during exercise. Significant positive correlations were obtained between PFR and LVEF at rest and during exercise. In summary, elevated blood pressure at rest and during exercise was thought to be the most important causative factor of LVH in hypertension.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1987

[Effects of parathyroid hormone on the cardiovascular system].

It has been well accepted that the bone and kidney are the principal organs of parathyroid hormone (PTH) actions, but there has been little work on the cardiovascular system. We evaluated the effect of PTH on the cardiovascular system of rats. In thiobutabarbital anesthetized rats, synthetic bovine parathyroid hormone, containing the amino acid (b-PTH 1-34) in dose of 0.1-10 micrograms/kg iv, caused dose related decrease in mean arterial blood pressure (MAP). On the other hand, there were significantly increase in heart rate (HR) and left ventricular contractile force. With the doses of 10 micrograms/kg, PTH decreased the MAP from 104.3 to 55.5 mmHg, left ventricular pressure (LVP) 122.1 to 96.4 mmHg, left ventricular end diastolic pressure (LVEDP) from 6.70 to 6.37 mmHg and LV dp/dt max 5,684 to 4,736 mmHg/sec. The HR, LV dp/dt/p and Vmax increase from 399.7 to 410.0 bpm, 95.5 to 108.4/sec, 98.2 to 107.4/sec, respectively. The propranolol, phentolamine, atropine and promethazine did not affect these actions of PTH. On the basis of these findings, we conclude that PTH has the directory vasodepressive action and the effect of augmentation of the left ventricular contractile force.

Animals↗
PubMed1986

Two cases of saline-responsive metabolic alkalosis associated with high urinary chloride concentrations.

Two particular cases of saline-responsive metabolic alkalosis associated with high urinary chloride concentrations were documented. In the first case, pseudoaldosteronism with long term glycylrrhetinic acid ingestion, and in the second case, probably salt losing nephropathy with extracellular fluid volume contraction were the putative causes of metabolic alkalosis, respectively. Sodium chloride loading with saline (0.9% NaCl) infusion to these patients corrected the accompanying hypopotassemic metabolic alkalosis. Recent trends in the pathophysiology of both saline-responsive and saline-resistant metabolic alkalosis were discussed.

Aged↗