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Biomedical subjects

Y Takabatake

Publications and source records attributed to Y Takabatake.

At least 55 records · Page 3Linked to original sources
PubMed1991

Antihypertensive effects of cicletanine and renal protection in Dahl salt-sensitive rats.

We designed experiments to reveal the antihypertensive properties of cicletanine, a novel antihypertensive drug, in Dahl salt-sensitive (Dahl-S) rats. Cicletanine (39 mg/kg body weight per day for 6 weeks) ameliorated the development of hypertension in Dahl-S rats fed a high-salt (4% NaCl) diet. This blood pressure reduction was associated with a decrease in heart weight and vascular wall thickness. Moreover, urinary prostacyclin (PGl2) excretion was increased with cicletanine treatment, being inversely related to systolic blood pressure. Proteinuria and urinary excretion of n-acetyl-beta-D-glucosaminidase were decreased and glomerular filtration rate was increased with this treatment. Morphological investigation revealed an improvement in glomerulosclerosis, renal tubular damage and intrarenal arterial injury in the salt-induced hypertensive rats. In contrast, trichloromethiazide, which decreased blood pressure to the same extent as cicletanine, lowered urinary PGl2 excretion and generally did not ameliorate the deteriorated renal functions and morphological abnormalities. Thus, these data indicate that cicletanine ameliorates the development of hypertension in Dahl-S rats and protects the cardiovascular and renal systems against the injuries seen in the hypertension. The enhanced vasodepressor PGl2 synthesis probably participates, to some extent, in these beneficial properties of long-term cicletanine treatment.

Animals↗
PubMed1991

Evidence for medial-mass regression in the vascular wall of Dahl hypertensive rats by cicletanine treatment.

We designed experiments to investigate the effects of cicletanine, a novel antihypertensive drug, on medial hypertrophy in Dahl rats susceptible to salt-induced hypertension (Dahl S rats). Cicletanine treatment (500 mg of cicletanine/kg of chow) for 6 weeks lowered blood pressure by 19% in Dahl S rats challenged with a high-salt (4%) diet. The blood pressure reduction was associated with a significant decrease in weight of the aortic vessels. Morphological examination revealed that this treatment decreased medial hypertrophy and expansion of intimal tissue, in concert with resolution of the periarteritis in the intrarenal arteries. In fact, the content of actin in the aortic wall, analyzed by SDS-PAGE, was decreased significantly with this treatment and myosin content was reduced to the same extent as well. Moreover, cicletanine per se lowered protein synthesis in randomly cycling cultured vascular smooth muscle cells (VSMCs) from Sprague-Dawley rats. Actin formation by VSMCs was decreased with cicletanine. Thus, these data indicate that chronic cicletanine treatment produces regression of the medial hypertrophy in Dahl S rats. Direct inhibitory effects on cytoskeleton protein synthesis, as well as its antihypertensive action, are partly responsible for this regression in vivo.

Animals↗
PubMed1991

Lower pacemaker in high degree atrioventricular block is modulated electrotonically by atrial excitations.

To see if the lower pacemaker in patients with atrioventricular (AV) block was modulated electrotonically by atrial excitation, we studied R-R intervals in two groups of AV block patients using a phase response curve (PRC). Group I consisted of 20 patients with high degree AV block, including seven patients in whom complete AV block was transiently observed in the course of acute inferior myocardial infarction. Group II consisted of 19 patients with complete AV block. In every patient, PRC was obtained from the continuous electrocardiogram by plotting each R1-R2 interval (response) on the ordinate as a function of the R1-Px interval (phase, x = 1, 2 ...) on the abscissa. In Group I, the R-R interval was prolonged when the P wave fell in the initial half of the R-R interval, and was abbreviated when the P wave fell in the later half of the cycle. In Group II, the fluctuation of the R-R interval was minimum. In ten group I patients, with the improvement of the AV block, PRC became sharper and transition from prolongation to shortening occurred at shorter R-P intervals. We conclude that, in Group I, lower pacemaker was modulated electrotonically by atrial excitations through decreased electrical coupling along the AV node.

Aged↗
PubMed1991

Nitroglycerin-induced transient coronary artery occlusion.

Nitroglycerin induced a paradoxical disappearance of a stenosed coronary artery in a 57-year-old man with non-Q wave myocardial infarction. On the coronary angiogram, the left anterior descending coronary artery (with a 95% stenosis) became completely invisible 2 min after 0.3 mg sublingual nitroglycerin. Three minutes later, the artery was opacified again. This transient occlusion may have resulted from a passive collapse of the distal portion of the artery, due to insufficient access of nitroglycerin across the stenotic region.

Animals↗
PubMed1991

Aortic dissection associated with aortitis syndrome.

A 50-year-old woman with aortitis syndrome complicated by aortic dissection, is reported. The dissection was observed at the level of the descending thoracic aorta by aortography and at the intimal side of the dilated aorta on CT. An aneurysm of the right subclavian artery and a diffusely thick wall of the abdominal aorta were also observed. This case suggests that the uneven wall of the aorta in aortitis syndrome might be dissected at the intimal side by dilatation.

Aneurysm↗
PubMed1991

Global and regional abnormalities of left ventricular diastolic filling in hypertrophic cardiomyopathy.

Left ventricular diastolic filling was studied by left ventriculography in 17 patients with hypertrophic cardiomyopathy (HCM). In 8 patients this manifested as a spadelike shape (HCM-S type) on the left ventriculogram, and in 9 patients as a banana shape (HCM-B type). Seven patients were studied as controls. Left ventricular end-diastolic pressure was higher in HCM than in controls. In HCM, peak filling rate was decreased from 1.57 +/- 0.28 of the control to 1.28 +/- 0.20 (p less than 0.05), and the time to peak filling rate was prolonged from 27 +/- 6%DT of the control to 37 +/- 7%DT (p less than 0.01). Serial volume analysis in diastole showed filling fraction was also significantly decreased to 8.2 +/- 4.1 (p less than 0.001) at the 25% diastole time and 29.6 +/- 7.2 (p less than 0.01) at half time, compared with 19.8 +/- 6.3 and 32.8 +/- 5.8 for controls, respectively. In HCM-S type, the rate of distention of left ventricular radial axes at the apical area was lower at early and mid-diastole. In HCM-B type, the rate at the basal area was lower at early and mid-diastole. Results suggest that the left ventricular diastolic filling in HCM was impaired not uniformly but regionally in the hypertrophic area at early and mid-diastole.

Adult↗
PubMed1990

Carbamazepine-induced bradycardia-tachycardia syndrome with pharmacological analysis and concurrent ECG monitoring.

The authors present a patient with carbamazepine-induced bradycardia-tachycardia syndrome, a rare type of drug-induced sinus node dysfunction. In this case, they established a clear-cut relationship between plasma carbamazepine concentration and the frequency of sinus arrests, following episodes of supraventricular tachycardia. As the pharmacological analysis of drug-induced sinus node dysfunction by concurrent ECG monitoring is very limited, the findings give an insight into the mechanism of this disorder.

Aged↗
PubMed1990

Right-to-left shunting through a patent foramen ovale caused by pulmonary hypertension associated with rheumatoid arthritis and Sjögren's syndrome: a case report.

This case report presents a fifty-four-year-old woman with right-to-left shunt in the atrium. It seemed clinically at first that the shunt was due to atrial septal defect. However, she also had pulmonary disease associated with rheumatoid arthritis and Sjögren's syndrome. At autopsy atrial septal defect was not evident, but a patent foramen ovale and pulmonary artery disease were observed. This case suggests that pulmonary hypertension secondary to rheumatoid arthritis and Sjögren's syndrome could lead to right-to-left shunting through a patent foramen ovale.

Arthritis, Rheumatoid↗
PubMed1990

Headache angina with fatal outcome.

We report 2 fatal cases of angina pectoris in patients who complained primarily of headache during the ischemic attack. The first patient, who was hospitalized because of headache and chest pain, demonstrated repeated ST-segment elevation and fatal ventricular fibrillation on ambulatory ECG monitoring. The second patient had post-infarction angina preceded by headache and by ST-segment elevation in the precordial leads. She eventually died of reinfarction. The mechanism of the headache in relation to the angina pectoris is discussed.

Aged↗
PubMed1990

Coronary artery disease associated with aortitis syndrome in older patients.

Coronary artery disease associated with aortitis syndrome was studied in relation to the coronary artery lesions and age. Four (21%) of 19 patients with aortitis syndrome had coronary artery disease and the mean age of the 4 patients was 53 +/- 14 years. The coronary artery lesions included ostial stenosis in 2 patients and main branch stenosis in 2, but both types of lesion were isolated. The latter patients were older and had coronary lesions like arteriosclerosis on angiogram. Myocardial infarction and congestive heart failure were not present, but a severe coarctation of the aorta was observed in the latter. It was suggested that coronary artery disease might not be rare past middle age, and might include coronary ostial stenosis caused by aortitis and coronary main branch stenosis probably based on secondary arteriosclerosis whose onset was past middle age.

Adult↗
PubMed1990

[Pre-ejection flow in the left ventricular outflow tract: a pulsed Doppler echocardiographic study].

Pre-ejection flow (PEF) has been recognized as the flow of short duration toward the cardiac base in the left ventricular outflow tract. In the present study, PEF was analyzed by pulsed Doppler echocardiography to determine the contribution of left ventricular contraction to the genesis of PEF. The study subjects consisted of 20 patients with lone atrial fibrillation (Af) and 30 patients with premature ventricular contractions (PVC) without other cardiovascular diseases. Phonocardiogram and electrocardiogram were simultaneously recorded with Doppler signal of PEF. PEF was clearly detected in only 18 patients with PVC; in the remaining 12, it was not recorded or could not be differentiated from the signals of the preceding left ventricular diastolic filling. Results were as follows: 1. PEF in the cases with sinus rhythm appeared before the Q wave; whereas, it appeared after the Q wave in the cases with Af or PVC, and the peak of PEF coincided with the first heart sound on the phonocardiogram. 2. The duration of PEF was 93.6 +/- 15.4 msec in sinus rhythm, 60.6 +/- 14.2 msec in Af, and 87.5 +/- 19.4 msec in PVC. 3. Peak velocities of PEF in Af and PVC were significantly less than peak velocity of PEF in sinus rhythm. 4. Peak velocity of PEF in PVC with left bundle branch block tended to be less than that in PVC with right bundle branch block.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Fibrillation↗
PubMed1990

[Comparison of two-dimensional echocardiography and Tl-201 SPECT in the evaluation of ischemic heart disease].

To ascertain the influence of severity of coronary stenosis and the presence or absence of collateral circulations on echocardiographic (2DE) asynergy or abnormal myocardial perfusion by exercise Tl-201 SPECT, we performed a correlative study of 40 patients undergoing coronary angiography, including 27 with myocardial infarction and 13 with angina pectoris, whose mean age was 55 years. Each view of the left ventricle (LV) obtained by both methods was assigned to five segments; i.e., anterior, septal, inferior, lateral and apical. The correlation of abnormal segments was investigated using both methods. The segments showing a severe perfusion defect coincided those with severe asynergy. Among 116 segments with normal perfusion, 99 (85%) revealed normal wall motion, but the remaining 15% showed asynergy. Among 84 segments with abnormal myocardial perfusion, 26 (31%) had normal wall motion, and most of these were non-infarcted regions. Concerning the severity of coronary artery stenosis, greater than 99% coronary arterial stenoses existed in most of the segments showing a complete defect or incomplete redistribution on Tl-201 SPECT and akinesis or hypokinesis on 2DE. Collaterals were observed in 22% of the segments with a complete defect and 66% of segments with incomplete redistribution; whereas, there was no significant correlation between the severity of LV wall motion abnormality and the presence or absence of collaterals. The severity of asynergy is possibly related to the severity of abnormal myocardial perfusion, however, asynergy could occur at the site of ischemic regions where Tl-201 SPECT can not detect the abnormalities. In patients with myocardial infarction who show incomplete redistribution by exercise Tl-201 SPECT, temporal ischemia of collaterals might cause such a perfusion abnormality.

Adult↗
PubMed1988

Coronary artery aneurysms and congestive heart failure--possible long-term course of Kawasaki disease in an adult--a case report.

Multiple coronary artery aneurysms, rarely seen in patients with atherosclerotic heart disease, can be frequently observed in children with Kawasaki disease. However, their long-term clinical courses still remain obscure. A thirty-nine-year-old male came to our clinic because of congestive heart failure. A left ventriculogram revealed highly reduced wall motion. A coronary angiogram showed left main trunk aneurysm with complete occlusion of the left anterior descending artery and ramification of the right coronary artery close to the ostium. Six months after discharge, he died suddenly. On autopsy, aneurysms were observed in the left main trunk and right coronary artery, together with an old anteroseptal myocardial infarction. Although he did not have a clear history of febrile disease in childhood, he was highly suspected to be a long-term survivor of Kawasaki disease because of the unique form and distribution of the coronary artery aneurysms.

Adult↗
PubMed1985

The size of kidney with renovascular hypertension in patients with aortitis syndrome.

Renal atrophy due to the renal artery stenosis associated with aortitis syndrome was studied in seven patients. Severe hypertension, high plasma renin activity and normal overall renal functions were present in all. The luminal diameter of the stenosed renal artery seen on the angiogram was less than 1.5 mm at the maximum area of stenosis in all patients. The size of the kidney with renal artery stenosis was diminished, ranging from 8.0 to 14.0 cm in longitudinal diameter on the nephrogram. Histological findings of the small kidney revealed ischemic atrophy. Although the rate of progression of the arterial stenosis was uncertain, the collateral circulation was found to be rich. Renal atrophy was not frequent and not marked even in the presence of high grade renal stenosis or obstruction in case of renovascular hypertension secondary to the arteritis.

Adolescent↗
PubMed1984

Rapid progression of an aortic lesion in a patient with aortitis syndrome.

In a 28-year-old woman with aortitis syndrome, repeated aortography revealed the development of a coarctation of the abdominal aorta occurring over a period of 1 year. Clinical and surgical examinations showed evidence of inflammation and ruled out other diseases during that time. This suggests that in cases of aortitis syndrome arterial lesions may show rapid progression over short time periods and in the absence of untoward events.

Adult↗
PubMed1981

Long-term clinical effect of calcium inhibitors in hypertrophic cardiomyopathy compared to the effect of beta-blocking agents. A preliminary report with special reference to the beneficial effect of nifedipine on angina pectoris.

Long-term clinical effects of beta-blockers (propranolol in most cases) and calcium inhibitors (nifedipine in most cases) were studied in 16 patients with hypertrophic cardiomyopathy. On overall subjective symptoms, beta-blockers were effective in 50% of symptomatic patients, while calcium inhibitors were effective in only 33%. On angina pectoris, however, calcium inhibitors were superior to beta-blockers in our patients. Blood pressure decreased with each drug, and the decrease was significant with nifedipine. Otherwise there was no change in physical findings with either drug. Long-term (more than 6 months) use of beta-blockers resulted in an increase in cardiothoracic ratio on chest X-ray, a decrease in left ventricular ejection fraction on echocardiogram and more pronounced ST-T change on electrocardiogram. Prolonged use of nifedipine resulted in a slight decrease in cardiothoracic ratio, but no systematic change on echocardiogram and on electrocardiogram.

Adrenergic beta-Antagonists↗