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Biomedical subjects

S Sadoshima

Publications and source records attributed to S Sadoshima.

At least 145 records · Page 8Linked to original sources

Autoregulation of cerebral blood flow in young and aged spontaneously hypertensive rats (SHR).

Autoregulation of cerebral blood flow (CBF) to the controlled hemorrhagic hypotension was studied in young adult spontaneously hypertensive rats (SHR, 3.4 months of age) and aged SHR (20.3 months). There were no differences in average values for mean arterial pressure and baseline CBF between two groups of rats. During hypotension, however, CBF was more reduced in aged SHR than in young SHR, indicating that the lower limit of cerebral autoregulation is shifted to a higher level in aged SHR. Such upward shift of the autoregulation is likely due to a long-lasting hypertension which may lead to the diminished vasodilatory response of the brain to hypotension.

Aging↗

Pulmonary hemorrhage in experimental cerebral ischemia in mongolian gerbils. Brain metabolism and lung pathology.

Pulmonary changes in acute cerebral ischemia were studied in anesthetized Mongolian gerbils, in which both carotid arteries were occluded simultaneously. Lactate, pyruvate and adenosine triphosphate (ATP) in the brain were measured as indicators of the severity of cerebral ischemia. Microscopic changes in the lung were arbitrarily scored from 0 (normal) to 3 points (severely affected) by the grade and the extent of lesions. Mean arterial pressure (MAP) was also measured through the cannulated femoral artery before and after carotid artery occlusion in a separate group of animals. Cerebral lactate was increased while ATP decreased in ischemic animals in which pulmonary changes such as intra-alveolar hemorrhages were prominent and frequent. The lung pathology score averaged 1.3 in animals with severe ischemia (lactate greater than or equal to 10 mM/Kg), 0.7 in moderate ischemia (5-10 mM/Kg) and 0.3 in mild or no ischemia (less than 5 mM/Kg), respectively, suggesting that severe brain ischemia may cause fulminant pulmonary changes. The mechanism of pulmonary lesions in acute cerebral ischemia is discussed.

Adenosine Triphosphate↗

[Central pontine and extrapontine myelinolysis following rapid correction of hyponatremia--report of an autopsy case].

A case of central pontine myelinolysis (CPM) following rapid correction of hyponatremia was reported and literatures were reviewed. The case was 61-year-old nonalcoholic female who had taken an operation of craniopharyngioma 23 years ago. Fifteen years later, she received re-operation for the recurrent tumor, followed by replacement therapy of corticosteroid and clofibrate. She was otherwise well until two weeks before entry, when she noticed abrupt onset of high grade fever, nausea, vomiting and general malaise. She was admitted to an emergency hospital because of weakness, disorientation and a slight impairment of consciousness, but she was able to speak and to take some food per os. Laboratory studies disclosed urinary tract infection and showed a serum sodium level of 117 mEq/l, potassium 2.9 mEq/l, a serum osmolarity 232 mO sm/l and urine osmolarity 141 mEq/l. She was diagnosed to have an exacerbation of adrenal insufficiency with hyponatremia and hypotonic dehydration triggered by urinary tract infection. Intravenous administration of vitamin B complex, electrolytes including KCL, 5% glucose solution and physiological saline with a large amount of corticosteroid was performed aggressively. Serum sodium concentration was raised to 161 mEq/l in two days, and the increased level had been maintained more than five days, resulting in coma and flaccid quadriplegia. During this period, there was no episode of hypotension, hypoglycemia, hypoxia nor hepatic failure which could have caused brain damage.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Insufficiency↗

Freeze substitution as a means of preserving meningeal vessel morphology.

This study compares freeze substitution with formaldehyde fixation as a means of preserving meningeal vessel morphometry. The diameters of vessels fixed by freeze substitution correlated very well with the in vivo diameters of the same vessels (correlation coefficient 0.9766). On the other hand, diameters of vessels perfusion fixed with 10% buffered formalin displayed poor correlation with in vivo diameters of the same vessels (correlation coefficient 0.1594).

Animals↗

Mechanisms of protection against stroke in stroke-prone spontaneously hypertensive rats.

The purpose of this study was to examine mechanisms by which sympathetic nerves protect against cerebral hemorrhage and ischemic infarction (i.e., "stroke") in stroke-prone spontaneously hypertensive rats (SHRSP). When unilateral superior cervical ganglionectomy was performed in SHRSP at 1 mo of age, development of cerebral vascular hypertrophy was inhibited and stroke developed only in the denervated hemisphere in 79% of the rats (P less than 0.05). Because "trophic" effects of sympathetic nerves on vascular growth may be less in older animals, unilateral sympathetic denervation was performed in SHRSP at 3 mo of age. The incidence of stroke was similar in the innervated and denervated hemispheres. In another group of rats that had unilateral ganglionectomy at 1 mo, we examined regulation of cerebral blood flow (CBF) when the rats were 4-5 mo of age, before neurologic signs of stroke. CBF, measured with microspheres, was similar in the innervated and denervated hemispheres during control conditions and during maximal vasodilatation produced by bicuculline. In contrast, when mean arterial pressure was raised acutely, CBF increased more in the denervated hemisphere than in the innervated hemisphere. We conclude that 1) in contrast to effects of denervation at 1 mo, sympathetic denervation at 3 mo of age (when trophic effects are less) does not lead to stroke, and 2) chronic denervation impairs the cerebral vasoconstrictor response to acute increases in arterial pressure.

Animals↗

Cerebral haemorrhage in Moyamoya disease at autopsy.

Nineteen fatal cases of occlusion of the circle of Willis, so-called Moyamoya disease, were examined clinicopathologically. Fresh and massive cerebral haemorrhage was confirmed in 14 and cerebral infarcts of 4 of 19 patients. Among these 14 patients, massive haemorrhage was found in the basal ganglia, thalamus and hypothalamus of 9, and in the thalamus, cerebral peduncle and midbrain of 5. Pathologically, fibrosing stenoses or occlusions involved the circle of Willis and its major branches in all cases. In 13 of 17 patients numerous collateral channels, muscular in type, paralleled the circle, bypassing the occluded natural passages, Rupture of dilated small muscular collateral arteries was demonstrated in fresh and old haemorrhagic lesions in 3 of the 14 patients. Saccular aneurysm of cerebral arteries in the subarachnoid spaces was present in two of the 19. No rupture involved the perforating arteries in the subarachnoid space. These findings strongly suggest that in patients with Moyamoya disease rupture of overgrown perforating arteries as collaterals in brain may be main cause of single or repeated cerebral haemorrhage. Stenoses or occlusions of these perforators are presumably an important factor in the occurrence of cerebral infarcts.

Adolescent↗

Cerebral blood flow during elevation of intracranial pressure: role of sympathetic nerves.

This study was performed to examine effects of increased intracranial pressure on cerebral blood flow (CBF) and to determine if sympathetic nerves modulate this response. Intracranial pressure was raised by infusion of artificial cerebrospinal fluid into a lateral ventricle of rabbits. Increases in intracranial pressure were similar in the lateral ventricles and cisterna magna. Graded increases in intracranial pressure from base line of 7 to 96 mmHg produced graded reductions in CBF (measured with microspheres). Reductions in blood flow were heterogeneous: elevation of intracranial pressure from 7 +/- 1 to 46 +/- 3 (SE) mmHg reduced blood flow to the cerebrum by 33 +/- 5% and blood flow to the medulla by only 5 +/- 2% (P less than 0.05). Reduction of intracranial pressure to normal levels produced marked reactive hyperemia in all areas of the brain. Although sympathetic nerve traffic increased fivefold during intracranial hypertension, superior cervical ganglionectomy did not affect CBF. In other experiments, electrical stimulation of sympathetic nerves at 4 Hz reduced blood flow to skeletal muscle by 80% but did not affect CBF; stimulation at 15 Hz produced a modest reduction in CBF. We conclude that 1) during increases in intracranial pressure, blood flow is better preserved to the medulla than to the cerebrum despite similar intracranial pressure in the two areas and 2) intense reflex activation of sympathetic nerves during intracranial hypertension does not affect CBF.

Animals↗

Response of cortical and pial arteries to changes of arterial CO2 tension in rats--a morphometric study.

Changes of the internal (d) and external diameter (D) of cerebral arteries in response to the various levels of arterial pCO2 were studied in anesthetized rats, of which brains were frozen in situ with isopentane cooled in liquid nitrogen. The parietal cortex was fixed with osmium tetroxide and stained with toluidine blue for morphometry of the cerebral arteries. In comparison with control animals (pCO2 = 41.2 mm Hg), the d/D ratio in animals with hypercapnia (pCO2 = 69.9 mm Hg) was increased by 11.7% in the pial arteries and 7.9% in the cortical arteries, indicating vasodilatation. In contrast, the d/D ratio in those with hypocapnia (pCO2 = 27.7 mm Hg) was decreased by 6.2% and 13.0%, respectively, indicating vasoconstriction. There was a significant linear correlation existing between the d/D ratio of either pial or cortical arteries and pCO2. It is concluded that the cortical arteries respond to changes of arterial pCO2 in a similar manner to the pial arteries.

Animals↗

Cerebral and aortic atherosclerosis in Hisayama, Japan.

This study of autopsy cases in the general population of the town, Hisayama, describes the incidence and severity of aortic and cerebral atherosclerosis in Japan. Atherosclerosis was more severe in the aorta than in the cerebral arteries of all age groups and its disparity became more conspicuous with age. In hypertensive cases, atherosclerosis was more severe in both the aorta and the cerebral arteries from and beyond the 6th decade of age. The severity of atherosclerosis in the aorta in those with systolic hypertension was lower under the age of 79 and higher after the age of 80 than in diastolic hypertension; the cerebral arteries were afflicted similarly by the two forms of hypertension. The serum cholesterol level correlated better with the severity of aortic than cerebral atherosclerosis.

Adult↗

Fibrinogen and low density lipoprotein in the development of cerebral atherosclerosis.

Cerebral arteries from 65 human subjects were examined by immunofluorescence, using antisera against human fibrinogen and low density lipoprotein (LDL). Deposition of fibrinogen and LDL was most frequent at the bifurcation of the middle cerebral arteries and least in the basilar arteries in all age groups. In general, deposition of LDL was associated with deposition of fibrinogen, and lone deposition of LDL in the absence of fibrinogen was only rarely seen. Fibrinogen was scattered in the intercellular spaces, and located in the inner layer or edges of the thickened intima of the bifurcation with increasing plaque formation. Fibrinogen was observed even in the subendothelial region of the uninvolved intima at the bifurcations. LDL was present in the cytoplasm of the endothelial cells in the earliest stage, and it increased in the extracellular stroma with increase in intimal thickening, corresponding closely to the distribution of perifibous oil-red-O-stained lipids. No LDL was detected in the uninvolved intima. The observations suggest that deposition of fibrinogen in the intima might precede LDL deposition and possibly play a more important role than LDL in the development of atherosclerotic lesions in the cerebral arteries, especially in their early stage. Severe atherosclerosis at the bifurcations may be in part due to increased permeation of these plasma proteins, possibly as a result of hemodynamic stress.

Adolescent↗

[Intracranial hemorrhage in autopsy cases with occlusion of the circle of Willis (author's transl)].

Seventeen autopsy cases with occlusion of the circle of Willis were examined clinicopathologically. These patients ranged in age from 8 years to 64 years and consisted of 6 males and 11 females. The following results were obtained. 1. Fresh and massive intracerebral hemorrhage was confirmed in 13 of 17 patients and cerebral infarct in 4 of 17 patients. 2. Among these 13 patients, massive hemorrhage was found in basal ganglia, thalamus and hypothalamus of 9 patients, and in thalamus, cerebral peduncle and midbrain of 4 patients. 3. Rupture of the dilated muscular-type arteries was noted in the thalamus and basal ganglia in 2 of 13 patients. Ruptured arteries with organization of the lumen were found in the old hemorrhagic foci in one of them. 4. Overgrown and dilated arteries, branching off from the circle of Willis, were confirmed in 11 patients. These arteries consisted of "perforating" arteries well developed as collateral circulation. 5. No ruture in these arteries of the subarachnoidal spaces was found in 11 patients. In one of them, a small saccular aneurysm was found. These findings strongly suggest that in patients with occlusion of the circle of Willis intracerebral rupture of overgrown "perforating" arteries as collateral circulation may be the main cause of intracranial hemorrhage and intracerebral hemorrhage due to rupture of the arteries may be repeated.

Adolescent↗

Primary ileal plasmacytoma arising in mixed low- and high-grade B-cell lymphoma of mucosa-associated lymphoid tissue type.

We report an extremely rare case of primary ileal plasmacytoma accompanied by mixed low- and high-grade B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) type. The radiographic and macroscopic features of the tumor were characterized by two constricting lesions in the ileum. Histologic examination of the resected specimen showed that one constrictive lesion was plasmacytoma and the other MALT lymphoma was low and high grade. The plasmacytoma seemed to have differentiated from the MALT lymphoma.

Adult↗