摘要:

Cerebral metabolic rate for glucose (CMRG) was measured using the 14C-deoxyglucose technique in a stroke model of the gerbil produced by bilateral common carotid artery occlusion. During 30 minutes of ischemia, 14C-deoxyglucose uptake in the brain was increased along the border zone between the ischemic and nonischemic area and decreased in the ischemic areas. During the early stage of reperfusion (2 or 3 to 30 minutes), CMRG increased 50 to 150% in the cerebral cortex, caudoputamen and thalamus and 270 to 320% in the hippocampus, globus pallidus and amygdala. During the late stage of reperfusion (15 to 45 minutes), heterogeneity of CMRG appeared in the cerebral cortex, caudoputamen and thalamus. CMRG decreased to less than 50% of the control value in the cerebral cortex but remained at 200 to 300% of control in the hippocampus, globus pallidus and amygdala. The latter structures exhibited a larger and more protracted increase in glucose metabolism than the other structures most probably due to the histological vulnerability to ischemia of these structures. The relationship between the transient increase of the glucose metabolism and cell function is discussed.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

This study was performed to determine whether, in hypertensive and normotensive rats, chronic sympathetic denervation impairs cerebral vasodilator responses during hypotension, and to determine whether there are regional differences in the autoregulatory response of brain vessels during hypotension. The superior cervical ganglion was removed on one side in stroke-prone spontaneously hypertensive rats (SHRSP) and normotensive (WKY) rats. Cerebral blood flow (CBF) was measured with microspheres when the rats were 5–6 months old. Chronic sympathetic denervation had little or no effect on cerebral vasodilator responses during acute hypotension in SHRSP and WKY. We suggest that the increase in incidence of ischemic infarction that we have observed previously after chronic sympathetic denervation in SHRSP probably is not the result of ischemia during episodes of hypotension. We also observed major regional differences in the response of cerebral vessels during acute hypotension in SHRSP: blood flow to brainstem was preserved better than flow to cerebrum and cerebellum. Thus the “lower limit” of the autoregulatory plateau differs in various regions of the brain in SHRSP.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

We studied the mechanical properties of canine basilar arteries subjected to experimental subarachnoid hemorrhage (SAH). Smooth muscle contractility was determined from pressure-diameter curves obtained after subjecting the basilar arteries to three different conditions: Krebs-Ringer solution (KRS), Krebs-Ringer solution containing serotonin (5HT), and saline solution. Pressure-diameter curves obtained in KRS and 5HT are biphasic and have sharp flexions that yield flexion points. The pressure level at the flexion point increases as vasospasm increases. Strong constriction is retained up to that pressure above which the constriction is released abruptly. These data suggest that increasing the intraluminal pressure dilates the spastic artery nonlinearly and that induced hypertension could relieve the cerebral ischemia caused by vasospasm if blood pressure were maintained above the flexion point. The contractile response of spastic arterial wall to serotonin remains unchanged after SAH although the spastic constriction increases progressively and becomes maximal seven days after SAH. The lesser the arterial wall stiffness, the more efficiently it constricts. This means that the diminution of arterial stiffness observed after SAH might be one of the factors promoting the development of vasospasm.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Weanling male and female, stroke-prone, spontaneously hypertensive rats (SHR/SP) were fed: 1) regular commercial rat chow, 2) low protein fish diet, 3) low protein fish diet + 1% saline, 4) low protein animal diet, and 5) low protein animal diet + 1% saline. The blood pressure of all of the SHR/SP rose rapidly reaching 240 mmHg at 90 days of age; blood pressure of low protein fish diet + 1% saline-fed SHR/SP rose most rapidly, reaching levels ranging from 258 to 300 mmHg. All of these animals developed acute strokes by 90 days of age; none of the other diet-fed SHR/SP manifested cerebral damage. The protein poor diets prevented normal growth, caused hypogonadism, and severely reduced pituitary and adrenal gland weights. The low protein diets were stressful causing significantly increased secretion of adrenocorticotrophic hormone and marked increases in triglyceride, free fatty acid, cholesterol, glucose, and B.U.N. levels. The mixed hemorrhagic-thrombogenic cerebral lesions occurred ipsilaterally in the parietal lobe, involved basal ganglia, and appeared in areas of brain tissue nourished by the middle cerebral artery. It is concluded that the inclusion of 1% saline drinking water with a low protein diet of fish tissue origin specifically, was synergistic in enhancing the propensity of SHR/SP rats to develop their genetically-programmed hypertension and stroke.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Permeability of brain capillaries of stroke-prone spontaneously hypertensive rats (SHRSP) was studied using labelling (horseradish peroxidase) and cytochemical techniques at the cellular level. In the cerebral capillary endothelium the tracer molecules were quickly transported by abundant transendothelial channels which directly connected the capillary lumen to the subendothelial space. Transendothelial channels are abundant and should be postulated as structural formations engaged in the increased transport of proteins across the capillary endothelium. Ultracytochemical studies revealed that the channels, bounded by indistinct delimiting membranes, initially had no acid phosphatase activity. With the passage of time, however, the channels showed acid phosphatase activity and were lined with distinct membranes. These observations suggested that the lysosomes might fuse with the transendothelial channels and might play an important part in the transport of macromolecules.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Cerebral microembolism was performed in rats by injecting radioactive calibrated 50 mu microspheres into the left internal carotid artery. The use of radioactive microspheres as embolic agents enabled the number of microspheres to be determined in each cerebral hemisphere. Edema was assessed 24 h after embolization by measuring brain water, sodium, and potassium content. Equiosmolal doses (40 mmol/kg) of glycerol or urea were injected i.p. at various times before sacrifice. Both treatments caused similar changes in water and electrolyte content, brain dehydration being maximal 30 min after urea and 2 h after glycerol injection. Cerebral energy metabolism and regional blood flow were evaluated at the times of maximal brain dehydration. Urea treatment resulted in an improvement of the cerebral circulation whereas glycerol treatment led to a deterioration of cerebral blood flow which cannot be explained by failure to reduce edema and the consequent microcirculatory impairment. Urea treatment had no marked effect on cerebral energy metabolism whereas glycerol injection resulted in an important increase in brain lactate level which may be relevant to the impairment of cerebral reperfusion. These results point out that administration of a metabolized solute like glycerol may exert deleterious effects on the ischemic brain.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Evidence was found for different outcomes to middle cerebral artery occlusion in the young genetically hypertensive stroke-prone rat (SHRSP) compared to sham operated controls and the Wistar Kyoto rat (WKY). Qualitatively and quantitatively different gross lesions marked by Evans blue-albumin, cortical atrophy, large areas of strikingly altered cortical histology, postoperative survival and motor behavioral deficits differentiate young SHRSP from sham operated controls and the normotensive WKY. We conclude that the limited focal lesion observed in normotensive and sham operated rats is primarily due to surgical trauma of exposing the vessel and passing the ligature deep to it. The grossly larger and qualitatively different lesion in the SHRSP is the result of an inadequate circulation provided by the dorsal cerebral arterial collaterals. Since the 5–6 week old SHRSP were only mildly hypertensive (systolic blood pressure 140 mm Hg), the inadequate collateral circulation appears to be related to either a genetic or acquired problem rather than being secondary to a vascular lesion of chronic hypertension.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Spinal cord arteries and arterioles of adult female rats were examined histochemically to determine their metabolic profiles. The metabolic pathways evaluated included those related to aerobic (oxidative phosphorylation, Kreb's cycle and respiratory chain) and anaerobic (glycolysis) capacity, hexosemonophosphate-shunt activity, beta-oxidation of fat and adenosine triphosphate utilization. The amounts of deoxyribonucleic and ribonucleic acids were determined as an indication of protein synthesis. The present findings indicate that arteries of the rat spinal cord are metabolically active with high capacities for both aerobic and anaerobic metabolism, and possess a significant potential for nucleic acid and protein synthesis. Lipid catabolism, via beta-oxidation of fat, may serve as one source of energy. The arteries also demonstrate a high capacity for utilization of adenosine triphosphate. In contrast, the spinal cord arterioles show a lower capacity for aerobic metabolism and lipid utilization, while anaerobic glycolysis may be a main source of energy. The arterioles also demonstrate a significant potential for nucleic acid and protein synthesis, in addition to a high capacity for adenosine triphosphate utilization.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

A patient developed a cerebellar infarction five weeks after a car accident. The pathophysiology and the medico-legal implications are discussed.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

We describe 3 cases of cerebral fat embolism associated with cardiac surgery. The autopsy findings suggested that in 2 cases, the embolic fat globules entered the systemic circulation directly as a result of protrusion of epicardial fat into the left atrial chamber along the suture line in one case, and through an atrial septal defect in the other. The characteristic latent interval between surgical trauma and onset of neurologic manifestations was lacking in both cases. The evolution of neurologic manifestations and the pathologic findings in the third case were similar to those usually seen in posttraumatic fat embolism. This study suggests that the pathogenetic mechanisms of cerebral fat embolism following cardiac surgery may vary in different cases. Also, it emphasizes the importance of autopsy in the investigation of this serious but preventable complication.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID