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Biomedical subjects

M Fujishima

Publications and source records attributed to M Fujishima.

At least 937 records · Page 52Linked to original sources
PubMedDate not supplied

Renal blood flow in acute cerebral ischemia in spontaneously hypertensive rats: effects of alpha- and beta-adrenergic blockade.

The influences of acute cerebral ischemia on renal hemodynamics were examined in spontaneously hypertensive rats in which cerebral ischemia was induced by bilateral carotid artery occlusion. Renal and cerebral blood flow were measured with a hydrogen clearance technique. Either phenoxybenzamine (0.5 mg/kg body wt) or propranolol (2 mg/kg) was given i.v. immediately after ischemia was induced to examine the drugs' effects on cerebral and renal hemodynamics. One hour after ischemia, cerebral blood flow was markedly reduced to 5, 3, and almost 0% of the preischemic value in the untreated, phenoxybenzamine-treated, and propranolol-treated rats, respectively. In contrast, renal blood flow at that time was decreased to 65, 88, and 67%, respectively. The calculated renal vascular resistance was similarly increased to 151% in the untreated and 136% in the propranolol-treated rats, but decreased to 82% in the phenoxybenzamine-treated rats. The present results indicate that in acute cerebral ischemia renal blood flow was considerably decreased with concomitant increased renal vascular resistance, and that such reduction in renal blood flow was minimized by alpha-adrenergic blockade but not by beta-blockade. It is concluded that activation of the alpha-adrenergic system in acute cerebral ischemia causes renal vasoconstriction.

Acid-Base Equilibrium↗
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Transient cerebral ischemic attacks in a Japanese community, Hisayama, Japan.

During a 20-year follow-up of 1,621 men and women aged 40 and over in Hisayama, Japan, 18 were found to have suffered transient cerebral ischemic attacks (TIAs) determined by clinical symptoms based on criteria proposed by the US Joint Committee for Stroke Facilities. The average annual incidence rate for the first TIA was 0.56 per 1,000 residents. Age and high blood pressure were strong determinants of TIAs for men. Nine of the 18 cases with TIAs (50%) subsequently developed cerebral infarction, an incidence significantly higher than that in the 1,603 subjects without TIAs (10.9%). Lacunar infarcts were most commonly found on pathologic examination of patients with TIAs who had had a subsequent stroke.

Age Factors↗
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Cerebrospinal fluid and arterial lactate, pyruvate and acid-base balance in patients with intracranial hemorrhages.

Lactate and pyruvate concentrations and acid-base balance in cerebrospinal fluid (CSF) and arterial blood were determined in patients with intracranial hemorrhages (28 subarachnoid hemorrhages and 15 intracerebral hemorrhages). A greater increase in CSF lactate and lactate-pyruvate ratio (L/P ratio) was observed in patients with impairment of consciousness, focal neurological deficits, poor prognosis, or CSF pressures higher than 300 mm H2O. A combination of CSF lactate greater than 2.5 mM per liter, L/P ration above 20, bicarbonate less than 20.4 mEq per liter, pH below 7.276, or arterial PCO2 below 31.5 mm Hg seems to indicate poor prognosis from intracranial hemorrhage. The mechanism of hyperventilation in acute cerebrovascular diseases and of CSF pH regulation in acid-base disturbances was also discussed.

Acid-Base Imbalance↗
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Lactate and pyruvate concentrations, and acid-base balance of cerebrospinal fluid in experimentally induced intracerebral and subarachnoid hemorrhage in dogs.

The effect of blood injected into either subarachnoid space or subcortical brain tissue upon lactate and pyruvate concentrations as well as acid-base balance of cerebrospinal fluid (CSF) was studied in the anesthetized dog. CSF lactate and lactate/pyruvate ratio (L/P ratio) increased progressively following the intracranial injection of blood and reached the maximum level at six hours after injection. These changes were significantly greater in animals with intracerebral hematoma than in those with subarachnoid hemorrhage (SAH). An increase in CSF lactate and L/P ratio in hemorrhagic CSF seems to be caused by two different factors. Shed blood cells per se produce lactate and pyruvate, and blood in the subarachnoid space and intracerebral hematomas cause secondary changes in brain tissue metabolism by a probable reduction of cerebral blood flow. Therefore, an increase in CSF lactate with a concomitant rise in CSF L/P ratio is a useful indicator for brain tissue hypoxia, even when CSF is hemorrhagic. The association of an increase in CSF lactate to a disproportionate decrease in CSF HCO-3 was also observed in these animals.

Acid-Base Imbalance↗
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Cerebral infarction following bilateral carotid artery ligation in normotensive and spontaneously hypertensive rats: a pathological study.

A pathological examination was performed on normotensive rats (NTR) and spontaneously hypertensive rats (SHR) following bilateral common carotid artery ligation. After ligation, diffuse and extensive cerebral infarcts in the carotid artery territory occurred frequently in SHR, while NTR occasionally had well-circumscribed small infarcts. The posterior communicating arteries, which are the major anastomotic channels connecting the carotid and vertebrobasilar systems, did not show any anomalies and were well developed in SHR and NTR. Vascular changes secondary to hypertension, such as fibrinoid necrosis or thickening of the wall, were not observed in SHR. Because of the paucity of structural difference of the blood vessels, the more diffuse and extensive cerebral infarcts in SHR after carotid occlusion were attributed to the hemodynamic difference rather than the morphological difference between the two groups. The results of the present experiment suggest that hypertension per se, i.e., hemodynamic factors, may be operative for the development of cerebral infarction.

Animals↗
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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.

Adult↗
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Long-term prognosis for cerebral infarction in relation to brain circulation--a 7-year follow up study.

Seventy-seven patients with cerebral infarction have been re-examined every year and followed for 7 years. Thirty-one patients had normal cranial blood flow (BF) and the remaining 46 had subnormal cranial BF, determined by the intravenous RISA method at the time of the original attack. During a 7-year follow up, 7 patients (22.6%) of the normal cranial BF group died; 3 of stroke and the remaining 4 from other causes, while 24 patients (52.2%) of the subnormal cranial BF group died; 13 of stroke and the remaining 11 of various diseases. The cumulative survival rate was consistently lower in the subnormal cranial BF group than the normal one. This difference reached statistical significance at 5 and 7 years of follow up. However, stroke recurrence did not differ significantly between the 2 groups. This suggests that a decreased cranial BF is an indicator of a poor long-term prognosis.

Cerebrovascular Circulation↗
PubMedDate not supplied

Effects of acute hypertension on brain metabolism in normotensive, renovascular hypertensive and spontaneously hypertensive rats.

Effects of angiotensin-induced acute hypertension on cerebral metabolism were studied in normotensive (NTR), spontaneously hypertensive (SHR) and experimental renovascular hypertensive rats (RHR). Lactate, pyruvate and adenosine triphosphate (ATP) concentrations in the brain frozen in situ at 18--20 min after angiotensin infusion, which raised mean arterial pressure (MAP) by 28--62% of control, were determined by enzymatic methods. Supratentorial lactate was significantly increased to 135% of control in RHR, its increase being correlated with the degree of hypertension, wherease it remained unchanged in NTR or SHR. Furthermore, RHR showed a tendency toward increase in lactate/pyruvate ratio with a decrease in ATP despite no change of arterial acid-base balance measured simultaneously before and after acute induced hypertension. From the present study, it is postulated that some renal factor seems to contribute ischemic metabolic changes in RHR following acute hypertension. The possible effect of renin on the vascular permeability is discussed as the pathogenesis of hypertensive encephalopathy.

Acute Disease↗
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Spontaneous fall in blood pressure and reactivity of sympathetic nervous system in hospitalized patients with essential hypertension.

We evaluated whether reduction in sympathetic reactivity plays a major role in the spontaneous falls in blood pressure (BP) experienced during hospitalization by patients with essential hypertension. In the present case BP fell on the 2nd day of hospitalization. The responses of plasma catecholamines (CA) and BP to both handgrip and tilting were not altered during either the first 24 hours or the entire 7 days of hospitalization. The effect of phentolamine on BP was similar on the 1st, 2nd and 7th days. However, the resting levels of plasma norepinephrine before handgrip, tilting and phentolamine were significantly diminished on the 7th day, but not on the 2nd day. In conclusion, the diminution of sympathetic activity may be partly responsible for the hospitalization-induced fall in BP in the late stages.

Adult↗
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Prevalence of dementia in a Japanese community (Hisayama): morphological reappraisal of the type of dementia.

The prevalence of dementia was studied in 887 males and females Hisayama residents aged 65 or over (screening rate, 94.6%) using clinical information, neurological examination and dementia scales. We found 59 cases with dementia, the prevalence being in 6.7% of the screened population with females predominant. Vascular dementia was more frequent, with the ratio of vascular dementia to senile dementia of Alzheimer's type being 4.5 for males and 1.2 for females. Brain-pathology in 47 cases with dementia out of 59 was examined by CT scan or at autopsy during the subsequent 20-month period. Based on the morphologic diagnoses, vascular dementia was high in frequency at 55% of the demented cases, being three times higher than senile dementia of Alzheimer's type.

Aged↗
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A case of cardiac injury and acute renal failure induced by electrical burn.

Reported is a case of electrical burn associated with cardiac injury and acute renal failure in a 21-year-old man. After coming into contact with a high-tension cable, he became drowsy and oliguria developed. Twenty-four hemodialyses were required. Although the ECG findings revealed an inferior wall myocardial infarction, neither cardiac scintigram (201TlCl) nor ultrasonic cardiography revealed any local lesions. In this case the cardiac damage following electrical burn appeared different from true myocardial infarction.

Acute Kidney Injury↗
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Renal failure due to cholesterol embolization following percutaneous transluminal renal angioplasty.

Percutaneous transluminal renal angioplasty was performed in a 63-year-old diabetic woman who had renovascular hypertension with solitary functioning kidney and diffuse atherosclerosis. Angioplasty was technically successful, while thereafter, fever and myalgia of legs occurred with gradual increases in blood urea nitrogen and creatinine. The patient became uremic over a month after angioplasty and was placed on dialysis. She died six months after angioplasty. Autopsy revealed cholesterol embolization in bilateral kidney, pancreas and spleen, causing subacute renal failure. It is suggested that careful assessment of the patient should be made when determining the need for renal angioplasty for renovascular hypertension with a solitary functioning kidney.

Aged↗
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Cerebral blood flow and metabolism in an amnestic patient with left thalamic infarction--a positron emission tomographic study.

A 30-year-old man with left thalamic infarction developed severe amnesia. The positron emission tomography showed a decrease in cerebral blood flow and oxygen metabolism in the left thalamus and the ipsilateral frontal cortex (-20% to -12% of asymmetry index) both at day 11 and at 5 months after onset, although amnestic symptoms certainly improved during that period. The selective hypometabolism of the cerebral cortex suggested the remote effects of neuronal fiber disconnection between the left thalamus and the ipsilateral frontal cortex, which did not parallel the clinical course.

Adult↗
PubMedDate not supplied

Hypertension and dementia.

Vascular dementia (VD) is more prevalent than Alzheimer's disease (AD) in Japan, while AD is more common in Western countries. In the Hisayama study, a community-based cohort study of Japan, the prevalence of VD decreased in men during the 7-years (1985-1992) follow-up period, while the prevalence of AD remained unchanged both in men and women. The incidence of dementia increases with age, particularly AD aged 85 or older. Hypertension is a major risk factor for VD. Other risk factors include age, prior stroke, diabetes, alcohol intake, heart disease, and smoking. In contrast, age, a family history of dementia, a low educational level, and low physical activity are risk factors for AD. The role of hypertension in AD remains controversial; there has been positive, negative, or no association existed between blood pressure levels and AD. A recent clinical trial has disclosed the potential preventive effect of antihypertensive treatment on the incidence of dementia, especially of AD. Although the role of vascular factors for the pathogenesis of AD is becoming recognized, the effectiveness of antihypertensive treatment on the prevention of AD should be further clarified in the future studies.

Aged↗
PubMedDate not supplied

Ruptured duodenal varices: an autopsy case report.

Bleeding from duodenal varices is a rare and life-threatening complication of cirrhosis. The diagnosis and management of this disease remains problematic. We herein report an autopsy case of a patient who suffered from recurrent bleeding from duodenal varices. A 48 year-old man with cirrhosis presented with upper gastrointestinal bleeding. He had three episodes of massive melena during the 6 months prior to admission. However, the source of bleeding was not known. Emergent endoscopy revealed jet bleeding from varices in the second to third portion of the duodenum. Endoscopic ethanol injection sclerotherapy was attempted but rebleeding occurred and the patient died.

Carcinoma, Hepatocellular↗