Yo Takeya

Increase in extracranial atherosclerotic carotid lesions in patients with brain ischemia in Japan. An angiographic study.

Background and Purpose Atherosclerotic lesions in the cerebral arteries are distributed heterogeneously among different races. Intracranial carotid lesions are reported to be more common than extracranial carotid lesions among Japanese people, which is in sharp contrast to the pattern of cerebral atherosclerosis in whites. However, several Japanese clinicians have the impression, which has yet to be clinically proven, that extracranial carotid diseases are recently increasing in number. Methods One hundred twenty‐one patients who developed ischemic stroke and underwent angiography were examined in the study. Seventy were admitted to our clinic from 1963 to 1965 (early group); the remaining 51 patients were seen from 1989 to 1993 (recent group). Angiographic findings and vascular risk factors were compared between the two groups. Results Severe atherosclerotic lesions of the extracranial internal carotid arteries increased significantly during the ensuing 24 years between the end of the first period until the beginning of the second period (from 1965 to 1989), whereas lesions in the intracranial carotid system were similar between the two groups. Severe atherosclerosis in the extracranial internal carotid artery was more frequent in patients with diabetes mellitus, which proved to be the only risk factor that showed a temporal increase. Conclusions The proportion of severe atherosclerosis in Japanese patients with brain ischemia has been increasing in the extracranial internal carotid artery, while that in the intracranial carotid system remains unchanged. Such a temporal change may be the result, at least in part, of an increase in the prevalence of diabetes mellitus. (Stroke. 1994;25:766‐770.)

Effect of carotid artery ligation on regional cerebral blood flow in normotensive and spontaneously hypertensive rats.

Regional cerebral blood flow (rCBF) was measured in normotensive rats (NTR) and spontaneously hypertensive rats (SHR), in a lightly anesthetized state and with control of Pacos by artificial ventilation. Without carotid artery ligation, NTR and SHR showed almost identical rCBF values and distribution, despite s gnificantly elevated levels of blood pressure in SHR. Bilateral carotid artery ligation, however, caused much more pronounced decreases of rCBF (ischemia) in SHR than NTR, in regions supplied by the carotid artery. The reduction of rCBF in SHR was rather homogenous and symmetrical. Mechanisms causing the differences between NTR and SHR are discussed.

Prognosis of occlusive cerbrovascular diseases in normotensive and hypertensive subjects.

Comparison of the clinical features, especially prognosis, in cerebral infarction was made between nine normotensive subjects and 16 hypertensive patients with an 80% stenosis or occlusion of the intracranial or extracranial arteries. Our own criteria for evaluating hypertension were employed on the basis of the following items: a past history of hypertension, blood pressure levels on admission and during hospitalization, degree of retinopathy, and ECG changes. In 17 of 25 cases, brain circulation was measured by the intravenous RISA technique. Abnormalities of the EEG and reduction of cranial blood flow were greater, and an early prognosis for neurological deficits in the first two months after the onset of stroke was poorer in the hypertensive group than inthe normotensive group. These results are contradictory to the observations of others.

Bilateral Reduction of Hemispheric Blood Flow in Patients With Unilateral Cerebral Infarction

Bilateral hemispheric blood flow was determined by the intravenous RISA technique in patients with unilateral cerebral infarction. Of all 29 patients, bilateral reduction of cerebral blood flow (CBF) was demonstrated in 13, of whom hemispheric vascular resistance was significantly increased and arm-to-brain circulation time prolonged. In these cases with bilateral subnormal CBF, blood flow on the noninfarcted side tended to increase if the patients were conscious at the time of onset, whereas it remained unchanged even 77 days following stroke if their consciousness was impaired. The already lowered blood flow on the infarcted hemisphere, however, did not increase for a relatively long period of time after the onset. It appears that bilateral reduction of CBF in patients with unilateral infarction is primarily caused by diffuse cerebral vascular changes and some additional systemic circulatory disorder. The possibility of other factors participating is also discussed.

Elevated plasma catecholamines without alteration in cardiovascular responsiveness in young men with borderline hypertension

Plasma catecholamines and cardiovascular responses to upright posture, exogenous noradrenaline (NA), and isoproterenol (IP) were examined in 20 young men with borderline hypertension and in 10 age-matched normotensive volunteers. Resting plasma NA and adrenaline (Ad) levels were higher in the borderline hypertensive patients. Significant correlations were found among plasma NA and mean blood pressure (MBP) or heart rate (HR), and between plasma Ad and HR in all individuals in the supine position. The increases in plasma NA were similar between groups for orthostatic positions. Pressor response to exogenous NA and chronotropic response to exogenous IP were not augmented in borderline hypertensives. A negative correlation was found between plasma NA before infusion and the increases of MBP produced by NA or the increases of HR produced by IP in all the individuals. Our observations suggest that there is hyperactivity of the sympathoadrenal system without enhancement in cardiovascular reactivity to catecholamines in young men with borderline hypertension.

Catecholamines, Angiotensin II and Sodium Concentrations in Cerebrospinal Fluid in Young Men with Borderline Hypertension

To evaluate the role of central nervous mechanisms and their relationships to the peripheral sympathetic nervous system in borderline hypertension, we measured catecholamines, angiotensin II (AII) and sodium (Na) concentrations in cerebrospinal fluid (CSF) with plasma catecholamines concomitantly in 12 young men with borderline hypertension and 7 age-matched healthy normotensive men on ordinary salt intake. Plasma norepinephrine (NE) and epinephrine (E) were higher in the borderline hypertensives than in the normotensives (NE: 239 +/- 15 vs 190 +/- 11 pg/ml, p less than 0.05, E: 83 +/- 9 vs 43 +/- 6 pg/ml, p less than 0.01). NE levels in CSF were also higher in the borderline hypertensives than in the normotensives (200 +/- 15 vs 150 +/- 18 pg/ml, p less than 0.05). In most of the subjects, CSF E and plasma and CSF dopamine levels were below the sensitivity of the assay. CSF NE correlated positively with both plasma NE (p less than 0.01) and mean blood pressure (p less than 0.05) in all subjects. Immunoreactive AII and Na concentrations in CSF did not differ between the borderline hypertensives and normotensives. These results suggest that peripheral sympathoadrenal overactivity in young subjects with borderline hypertension may be related to an altered function of central noradrenergic neurons. AII and Na in the central nervous system do not appear to have an important role in borderline hypertension.

Clinical features of cerebral infarction in the Japanese.

Abstract Recent vital statistics, autopsy records, and results obtained by population surveys show an increasing trend in frequency of cerebral infarction in Japan [1]. In view of these circumtances, it may be worth describing clinical features in occlusive cerebrovascular disease occurring in Japanese patients. The report is mainly concerned with the natural history of this disease as manifested by various clinical findings such as cardiovascular status, cerebral angiographic and neurophysiologic data, blood lipids profiles and blood coagulability.