Shozo Ogawa

Association of a Deletion Polymorphism of the Angiotensin-Converting Enzyme Gene with Left-Ventricular Hypertrophy in Japanese Women with Essential Hypertension; Multicenter Study of 1,919 Subjects

The relationship of an insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene to left-ventricular hypertrophy in individuals with essential hypertension (EH) was investigated in a large population of Japanese men and women. The ACE genotype of 762 subjects with EH (425 men and 337 women) and 1,157 healthy controls (604 men and 553 women) was determined by polymerase chain reaction analysis. The distribution of ACE genotypes did not differ significantly between patients with EH and control in both men and women. For women with EH, the DD genotype was positively associated with the thickness of the interventricular septum and inversely associated with the left ventricular end-diastolic dimension, both determined by echocardiography. In contrast, the DD genotype was not associated with any echocardiographic parameter in men with EH. These results indicate that the DD genotype is a risk factor for left-ventricular hypertrophy in Japanese women with EH, but not for Japanese men.

Complete evaluation of the cardiovascular lesions in 24 patients with Takayasu's aortitis using four-image, intravenous digital subtraction angiography

We studied the entire distribution of cardiovascular lesions with the use of intravenous digital subtraction angiography (DSA) in 24 patients having Takayasus aortitis. The aorta, its branches, pulmonary vessels, and left ventricle were assessed by neck (anteroposterior), abdominal (anteroposterior), and chest (right and left anterior oblique) images. DSA showed multiple arterial lesions (n = 24) including proximal renal artery stenoses (n = 4), pulmonary arterial stenoses (n = 4), inferior-superior mesenteric arterial anastomoses (n = 3), brachiocephalic arterial aneurysms (n = 2), aortic root aneurysm (n = 1), diffuse left ventricular hypokinesis (n = 1), subclavian steal phenomenon (n = 1), and right aortic arch (n = 1). The incidence of total occlusion was highest in the right subclavian artery (n = 12). Average percent luminal stenosis (mean +/- S.D.) over the aorta and its branches tended to be smaller in patients with prior corticosteroid therapy (17.3 +/- 14.6%) than in those without (22.0 +/- 9.8%), but the difference was not significant. DSA (four-series) was useful in assessing the whole disease spectrum and often revealed subclinical lesions in this disease.

The changes in regional myocardial surface area during coronary occlusion and reperfusion

SummaryFor the analysis of regional myocardial function, the measurement of regional myocardial surface area (RMA) was performed on the epicardial surface of myocardial segment lengths in a direction parallel to the superficial myocardial fibers (SLa) and at right angles to the first (SLb). In eight anesthetized dogs with opened-chests, measurements were done during a 60 s left anterior descending coronary artery occlusion and reperfusion. In the ischemic region, coronary occlusion resulted in dyskinesis in RMA, and the reduction of it during the ejection phase (ERA) decreased significantly at 10 s (p<0.05) and thereafter (p<0.01). Regional myocardial work (EWA) from the pressure-area loops during the ejection phase also decreased significantly at 10 s (p<0.05) and thereafter (p<0.01). The end-diastolic RMA (EDRMA) increased significantly at 30 s (p<0.01) and thereafter (p<0.01). In the non-ischemic region, compensatory changes were shown, namely ERA, EWA and EDRMA, increased significantly during occlusion. After reperfusion, recovery to the control level was prompt, and only EDRMA remained the increased value after 30 s (p<0.01). Between SLa and SLb, characteristics differed from each other, which suggested that the directional differences of SLs should be considered when regional myocardial function is assessed from unidirectional SL. The changes in RMA reflect both changes of SLa and SLb during coronary occlusion and reperfusion, and were more marked than each SL. Thus, the usefulness of RMA to assess regional myocardial function was demonstrated during coronary occlusion and reperfusion.

Effects of Vasodilators on Venous Tone in Vivo in Dogs

The authors investigated, in vivo, the effects of four vasodilators on venous tone in dogs. Baseline venous tone was determined from the pressure: diameter relationships in the inferior vena cava (VSIVC) and femoral vein (VSFV) as measured during several seconds of occlusion of the proximal inferior vena cava. All of the slopes were nearly linear. All vasodilators were adminstered in dosages sufficient to lower blood pressure by approximately 20%; these dosages also decreased systemic vascular resistance by 15% to 30%. Isosorbide dinitrate reduced VSIVC from 7.17 ± 0.81 to 5.81 ± 0.73 mmHg/mm and VSIVC from 59.4 ± 13.5 to 37.2 ± 6.6 mmHg/mm. Neither nifedipine nor nisoldipine altered VSIVC or VSFV. However, prazosin decreased VSIVC from 13.2 ± 3.3 to 10.7 ± 2.7 mmHg/mm and VSFV from 43.5 ± 11.3 to 29.9 ± 8.8 mmHg/mm. These results suggest that isosorbide dinitrate and prazosin decrease venous tone in vivo, whereas nifedipine and nisoldipine do not.