bluuebunny/crossref_metadata_2025 huggingface dataset:
Cerebral blood flow studies using N-isopropyl I-123 p-iodoamphetamine.
Authors: Kobayashi H , Hayashi M , Kawano H , Handa Y , Nozaki J , Yamamoto S , Matsuda H
Published: June 2011

Twenty patients with stroke were studied for cerebral blood perfusion abnormalities using N-isopropyl I-123 p-iodoamphetamine (IMP) and rotating dual gamma camera emission computed tomography (ECT). After a single scan, multiple transverse, coronal and sagittal section images were reconstructed with a minicomputer. In eighteen patients, we determined the values of regional cerebral blood flow (rCBF) in the region of interest using an image. Transmission computed tomography (CT) studies were also performed on the same day. ECT showed cerebral perfusion abnormalities in all cases, while CT showed abnormalities in only 10 cases. This technique seems to be useful for evaluating the rCBF in the deep brain.
Effect of common carotid occlusion on beta-adrenergic receptor function in cerebral microvessels.
Authors: Magnoni M S , Kobayashi H , Frattola L , Spano P F , Trabucchi M
Published: June 2011

beta-adrenergic receptors were measured in cerebral microvessels of gerbils and rats after ligature of the right or left common carotid artery. The results indicate a decrease in the number of beta-adrenergic receptors in brain microvessels of both ipsilateral and contralateral hemispheres. This event may reflect altered patterns of the neuronal regulation of brain microvasculature and may be related to cerebrovascular alterations which are concomitant with ischemia. Furthermore, the results show that the decrease in beta-receptor density is more pronounced in the left hemisphere, independently on the side of carotid occlusion. This finding suggests that microvessel function in the left side of the brain is more vulnerable to hypoxia effects.
Hemodynamics in hemorrhagic infarction--an experimental study.
Authors: Seki H , Yoshimoto T , Ogawa A , Suzuki J
Published: June 2011

Using the canine thalamic infarction model, hemodynamics, CO2 responses and thalamic EEG changes were studied in 7 dogs. Of the 7 animals, 4 showed hemorrhagic infarction and 3 did not, following recirculation after 6 hours of vascular occlusion. 1) The rCBF threshold for producing hemorrhagic infarction when recirculation following 6 hours of vascular occlusion was approximately 50% of the pre-occlusion level. 2) rCBF of the animals showing hemorrhagic infarction included hyperperfusion due to recirculation, and then fell to a level below the pre-occlusion level in a relatively short period. The CO2 response became disturbed both during occlusion and after release of occlusion. Thalamic EEG was nearly flat during vascular occlusion and recovery was not seen following recirculation. 3) rCBF of the animals not showing hemorrhagic infarction recovered rapidly to the pre-occlusion level due to recirculation. The CO2 response was somewhat disturbed during occlusion, but recovered following recirculation. Thalamic EEG was well preserved both during occlusion and after release.
Dye injection method for the demonstration of territories supplied by individual perforating arteries of the posterior communicating artery in the dog.
Authors: Inoue T , Kobayashi S , Sugita K
Published: June 2011

Various reported methods to demonstrate the territory supplied by an intracranial artery are designed to deal with major cerebral arteries or a group of perforating arteries. We have devised a technique to demonstrate the area supplied by individual small perforating arteries using different dyes with gelatin. A temporal craniectomy was made in the dog and the posterior circle of Willis was exposed via a subtemporal route under the operating microscope. After a portion of the posterior communicating artery including one perforating artery was trapped with clips, dye was injected through the cannule. The animals were immediately sacrificed and studied. The area supplied by an individual perforating artery occupied a relatively large and distinct area, and when two dyes for two different perforators were used, no significant overlapping of the stained territories was seen. This method is useful for the study of focal cerebral ischemia caused by occlusion of a fine perforating artery and in particular it will serve to clarify the importance of preserving each perforating artery in surgery in the region of the base of the brain such as that for basilar artery aneurysm.
Adenylate cyclase and histopathological changes in the gerbil brain following prolonged unilateral ischemia and recirculation.
Authors: Christie-Pope B C , Palmer G C , Chronister R B , Callahan A S
Published: June 2011

This study was designed to correlate histopathological changes in gerbil brain following unilateral primary and secondary ischemia to enzymatic-adenylate cyclase damage. At three hrs permanent occlusion of the right common carotid artery only minimal histological changes were evident in cerebrum, hippocampus, striatum and olfactory tubercle while the enzyme responses were unremarkable. Severe histological and enzymatic alterations were present at one hour of recirculation subsequent to 3 hrs of unilateral occlusion. Similar damage was evident at 6 and 24 hrs permanent occlusion. Principal enzyme damage was directed toward basal activity, as well as stimulation of the catalytic (forskolin-sensitive) sites on the enzyme complex. For the most part the transducer (GTP-sensitive) site was unaffected by ischemia until 24 hr ligation. These changes were observed in only those gerbils developing severe symptoms of stroke.
Asymptomatic carotid artery bruits in a population of elderly adults with isolated systolic hypertension.
Authors: Sutton K C , Dai W S , Kuller L H
Published: June 2011

A sample of 99 elderly (over age sixty) adults with isolated systolic hypertension were examined for cervical arterial bruits and systolic blood pressure measurements were taken in upper and lower extremities. The ratio of ankle to arm blood pressure (ankle/arm index) was used as a measure of the degree of obstruction in peripheral arterial circulation. The prevalence of bruit (asymptomatic in all cases) was high, with 24 bruits detected in 19 (19%) participants. This high prevelance of bruits is thought to be due to the blood pressure characteristics of this population. Those with bruit were found to have a 3.9 times greater chance of having an abnormal ankle/arm index. The relationship remained statistically significant even after controlling for the effects of age and smoking. These findings add further evidence to the hypothesis that asymptomatic cervical bruits are an indication of systemic vascular disease.
Lobar intracerebral hemorrhage: etiology and a long-term follow-up study of 32 patients.
Authors: Tanaka Y , Furuse M , Iwasa H , Masuzawa T , Saito K , Sato F , Mizuno Y
Published: June 2011

Thirty-two patients with lobar hematoma were encountered during a period of six and a half years. Of these patients, 13 had arterial hypertension, 7 had other etiologies, and the remaining 12 were without apparent etiology. In 5 of these patients, cryptic angiomas were suspected from angiograms and CT scans. In one young patient, there was a later recurrence of hemorrhage that resulted in death. Our experience in this series and a review of the literature have led us to conclude that, in young normotensive patients with lobar hematoma, surgical intervention may be a reasonable consideration so that evacuation of the hematoma may be accomplished and a detailed search for small angiomatous malformations may be carried out with a view to preventing recurrences.
Subarachnoid haemorrhage in the rat: effect on the development of cerebral vasospasm of lesions in the central serotoninergic and dopaminergic systems.
Authors: Svendgaard N A , Brismar J , Delgado T J , Rosengren E , Stenevi U
Published: June 2011

In the rat an intracisternal injection of blood induces an angiographically demonstrable biphasic cerebral arterial vasospasm. Chemical destruction of the central serotoninergic and dopaminergic pathways prior to the cisternal blood injection does not affect the spasm pattern after the subarachnoid haemorrhage. It is suggested that neither system plays a role in the development of spasm.
The effect of nicardipine on neuronal function following ischemia.
Authors: Grotta J , Spydell J , Pettigrew C , Ostrow P , Hunter D
Published: June 2011

In cerebral ischemia, it has been proposed that calcium influx into neurons results in irreversible cellular injury during reperfusion. We administered nicardipine, a dihydropyridine calcium entry blocker, by continuous subcutaneous infusion to twenty five rats beginning before (PR) or following (PO) ischemia, and compared somatosensory evoked potentials (SEPs) to twenty eight ischemic control animals. Comparable ischemic cellular changes were seen in the hippocampi of all animals. SEP amplitude was higher in both the PR (p less than .005) and PO (p less than .0005) groups compared to controls. This effect was found in all three components (P1, N1, P2) of the evoked response. Plasma nicardipine levels of 6-10 ng/ml were associated with mild hypotension. We conclude that nicardipine improved neuronal function as measured by SEPs when administered before or after ischemia, most likely by interrupting the cytotoxic events occurring in cortical neurons during reperfusion.
The effects of nifedipine and felodipine on cerebral blood flow during anoxic episodes.
Authors: Phillis J W , DeLong R E , Towner J K
Published: June 2011

Cerebral blood flow (CBF) in the rat was monitored by a venous outflow technique with an extracorporeal circulation, which allows for the continuous recording of flow over periods of several hours. Brief periods of anoxia increase the rate of flow. The dihydropyridine calcium antagonists did not affect basal flow rate and depressed the increase in CBF elicited by anoxia. These findings may have significant implications for the therapeutic use of dihydropyridine calcium antagonists in brain ischaemia.
Screening for depression in stroke patients: the reliability and validity of the Center for Epidemiologic Studies Depression Scale.
Authors: Shinar D , Gross C R , Price T R , Banko M , Bolduc P L , Robinson R G
Published: June 2011

This study examined the inter-observer reliability and validity of the Center for Epidemiologic Studies Depression Scale (CES-D) as a measure of depressive symptomatology in stroke patients, and its utility as a screening tool for depression in this population. The CES-D Scale is a brief questionnaire originally designed for use in community surveys. Twenty-seven non-aphasic patients enrolled in the Stroke Data Bank at the University of Maryland were interviewed by a research nurse using the CES-D. On the same day, each patient was independently evaluated by a research assistant using a psychiatric battery for depression and measures of cognitive, physical, and social functioning. Forty-one percent (11/27) of the patients were depressed according to clinical criteria for major or minor depression. With a cutpoint corresponding to the upper (most severe) 20% in community surveys, the CES-D Scale picked up 73% (8/11) of the depressed patients. In this sample no nondepressed patient scored over 16 on the CES-D (no false positives). The CES-D Scale scores correlated significantly with the other depression measures (r = .57 to r = .82, p less than .002) and did not correlate with the measures of cognitive, physical, or social functioning. Based on 24 patients who received a CES-D Scale score from both the nurse and the research assistant, inter-rater reliability was high (r = .76, p less than .001). Thus, the CES-D was found to be reliable and valid as a screening tool for assessing depression in stroke patients.
Laser endarterectomy: a comparison of thrombotic potential following CO2 laser vs surgical endarterectomy.
Authors: McVicker J H , Day A L , Savage D F , Abela G S , Roberts A J , Watson R L , Mehta J L
Published: June 2011

Although laser endarterectomy has recently been suggested as useful in the treatment of arteriosclerotic obstructions, the "in vivo" clotting effects have not been well delineated. In this study, the common carotid and femoral arteries of ten mongrel dogs were exposed, and alternating 1 cm segments of each artery were treated with surgical endarterectomy and low-powered CO2 laser endarterectomy. Segments were then harvested, and subjected to histologic examination and vascular prostacyclin synthesis determinations, as measured by 6-keto PFG1a radioimmunoassay. Gross examination and light and scanning electron microscopy showed increased platelet aggregation and more extensive damaging of the underlying media of the laser compared to the surgical segments. Six-keto PFG1a levels were significantly lower (p = 0.001) in the laser compared to surgical sites (mean 232 +/- 72 pg/mg vs 515 +/- 144 pg/mg), or controls (895 +/- 337 pg/mg). These findings suggest that laser endothelial evaporation leads to increased thrombotic potential in the early post-operative period in comparison to surgical endarterectomy.
Clinical identification of TIAs due to carotid stenosis.
Authors: Harrison M J , Iansek R , Marshall J
Published: June 2011

A retrospective case note survey of 139 cases of carotid territory TIAs was carried out. Angiographic evidence of carotid stenosis was more frequently encountered when the patient's attacks consisted of symptoms suggestive of ischemia of small cortical territories with involvement restricted to the arm or leg or to dysphasia. Attacks of hemiparesis affecting face, arm and leg, or arm and leg were less often associated with carotid stenosis. If patients described any attacks of a restricted nature the chance of finding carotid stenosis was 47%, if not 16%. It is argued that these findings are a reflection of the varied pathogenesis of TIAs, and the relevance of this heterogeneity to the interpretation of clinical trials is briefly mentioned.
A new combination therapy for selective and prolonged antiplatelet effect: results in the dog.
Authors: Kaplan S , Sauvage L R , Marcoe K F , Zammit M , Wu H D , Mathisen S R , Walker M
Published: June 2011

This study characterizes the effect of dazmegrel, a thromboxane synthetase inhibitor, on platelet function in the dog and introduces its potential use in combination with aspirin therapy. Ex vivo testing of dazmegrel alone was performed with three dosages and three administration regimens. Platelet aggregation response, malondialdehyde formation and prostaglandin metabolites generation were evaluated. To maintain complete thromboxane A2 inhibition, dazmegrel had to be given 3 times per day at dosages of not less than 6 mg/kg. The same result was achieved with a single daily administration of combined dazmegrel and aspirin in equal dosages of 3 mg/kg. Dazmegrel, both alone and with aspirin, increased and sustained heightened levels of prostacyclin, unlike the simultaneous inhibition of both prostaglandin metabolites seen with aspirin therapy alone. Because the combination of dazmegrel and aspirin effectively blocks thromboxane A2 formation and also enhances prostacyclin formation, the synergistic action of these agents increases their combined antiplatelet effect to a level not attainable by either agent alone. The significance of this combined therapy warrants further experimental study and may soon merit clinical trial for the prevention of stroke and other major thrombotic complications.
Echocardiographic evaluation of young adults with nonhemorrhagic cerebral infarction.
Authors: Biller J , Johnson M R , Adams H P , Kerber R E , Toffol G J , Butler M J
Published: June 2011

We reviewed echocardiographic findings in patients aged 15 to 45 years with acute nonhemorrhagic cerebral infarction (NHCI). Among 132 patients with NHCI, 96 (72.7%) had M-mode and two-dimensional echocardiography, including contrast echocardiography with intravenous saline injection when clinically indicated. Echocardiograms were abnormal in 33 patients. Of these, 7 had other conditions that could cause NHCI. Echocardiography corroborated the clinical diagnosis of a cardiogenic source for cerebral infarction in 17 others. The other 9 had no other clues for cardiovascular disease. Potential etiologies of NHCI diagnosed by echocardiography in these 9 cases included: paradoxical embolism, 5 patients; right atrial myxoma, 1; rheumatic mitral valve vegetation, 1; myxomatous mitral valve (marantic endocarditis at postmortem), 1; and left atrial enlargement associated with decreased left ventricular function, 1. Routine echocardiography frequently conveys useful information in patients under age 45 with NHCI. In young patients with cerebral embolism of unknown etiology if routine M-mode and two dimensional echocardiographic studies are normal, contrast echocardiographic studies should be performed to rule out intracardiac shunts and the possibility of paradoxical cerebral embolism.
Ejection fraction response of the left ventricle of the heart to acute cerebrovascular accident in patients with coronary artery disease.
Authors: Front D , Frankel A , Israel O , Aharon Y , Satinger A , Linn S
Published: June 2011

The ejection fraction (EF) of the left ventricle was measured by radionuclide ventriculography in 64 patients during an acute cerebrovascular accident. Sixteen patients (12 with coronary artery disease) died within two weeks of the onset of symptoms and had only one EF measurement. In the remaining 48 patients, the EF was also measured two weeks and three months after the acute event. The ejection fraction of the patient who died soon after the acute stroke (52 +/- 18) was significantly lower than that of the patients who survived (64 +/- 10) (p less than 0.01). Of the patients who survived, 28 without history of coronary disease had an EF of 67 +/- 10 during the acute event. It was significantly higher than that measured after two weeks (60 +/- 10) p less than 0.01). In 10 patients with history of chronic stable angina pectoris, the EF (59 +/- 10) was significantly lower in the first study compared to that measured in the second (69 +/- 10) (p less than 0.02). Ten patients with no evidence of ischemia but with a history of myocardial infarction had a higher EF (61 +/- 11) during the first study as compared to the second (51 +/- 11) (p less than 0.05). In all patients there was no significant difference in the EF measurements between the second and the third study. It is suggested that the EF response of the left ventricle of the heart to the acute cerebrovascular accident is similar to that observed in a stress test.(ABSTRACT TRUNCATED AT 250 WORDS)
Cerebrovascular disease morbidity in the United States, 1970-1983. Age, sex, region, and vascular surgery.
Authors: Gillum R F
Published: June 2011

Data from the National Hospital Discharge Survey were reviewed to assess trends in hospital discharge rates for cerebrovascular disease in the United States between 1970 and 1983. Hospital discharge rates showed little consistent change during the 1970's but increased after 1979. Hospital case fatality declined during the same period. Cerebrovascular disease discharge rates were higher among older persons, men, and blacks. Hospital case fatality was higher in older persons and blacks. Rates of cerebral arteriography and endarterectomy of vessels of the head and neck increased between 1979 and 1983. Methodologic problems in monitoring cerebrovascular disease trends are reviewed and recommendations for future research presented.
Scavenger activity in monocyte-derived macrophages from atherothrombotic strokes.
Authors: Yatsu F M , Alam R , Alam S
Published: June 2011

Foam cells are lipid-laden macrophages derived primarily from circulating mononuclear cells and are a characteristic feature of atheromatous lesions. The exact role of these foam cells in the pathogenesis of atherosclerotic lesions remains uncertain, but one potential function is to take-up and process excess interstitial arterial lipoproteins, suggested by their extraordinary ability to engulf enormous quantities of modified low density lipoproteins by the so-called "scavenging pathway." To test this possibility, monocytes from 15 atherothrombotic brain infarct patients and age and sex matched controls were isolated and cultured for 7-8 days in 20% normal serum. The monocyte-derived macrophages were investigated for their ability to bind, internalize and degrade both native and modified (acetylated) LDL labelled with 125Iodine. While native LDL was metabolized similarly, stroke macrophages displayed significantly reduced ability to scavenge modified LDL. These findings suggest that insufficient processing of interstitial arterial cholesterol by monocyte-derived macrophages may contribute to the aggravation of atheroma formation. This inadequacy is likely further compromised by reduced levels of serum high density lipoprotein since the absence of a cholesterol-acceptor will promote the slow but continued accumulation of lipids and the formation of foam cells.
Spontaneous history of asymptomatic internal carotid occlusion.
Authors: Hennerici M , Hülsbömer H B , Rautenberg W , Hefter H
Published: June 2011

Forty-nine patients with ICA occlusion, who presented without any neurological signs or symptoms, were prospectively followed for an average of 31.2 months. Eight patients (16%) suffered a stroke during follow-up, of which five were within the vascular territory of the occluded artery--5 patients (10%) developed TIAs 4 of which were ipsilateral to the occluded artery. Non-invasive vascular follow-up did not reveal a progression of extracranial arterial disease in the majority of later symptomatic patients. Twenty-three patients (46.9%) died during follow-up, coexisting coronary artery disease being the major cause of death.
Pentoxifylline: cerebral blood flow and glucose utilization in conscious spontaneously hypertensive rats.
Authors: Johansson B B
Published: June 2011

Pentoxifylline, 0.30 mg/kg/min, significantly reduced cerebral blood flow by 10-44% in 19 of 23 regions studied in conscious spontaneously hypertensive rats. Bilateral ligation of the common carotid arteries reduced cerebral blood flow to 24-46% of resting values in 20 structures; a further reduction to 10-27% of resting values was seen after pentoxifylline in 10 cortical or subcortical structures. Thus, in conscious hypertensive rats, there is no evidence that pentoxifylline redistributes blood flow from normal to low flow brain regions. Pentoxifylline did not reduce the metabolic rate of glucose.
Sudden hemiparesis as the presenting sign in cryptococcal meningoencephalitis.
Authors: Saul R F , Gallagher J G , Mateer J E
Published: June 2011

A previously healthy young man presented with an acute stroke syndrome and was found to have cryptococcal organisms in the CSF. Though an initial CSF examination for an infectious etiology was negative, a second lumbar puncture was performed because of hypoglycorrhachia, which established the diagnosis. An uneventful recovery followed the administration of Amphotericin B and 5-Flucytosine. A literature search revealed only one previously reported case of cryptococcal meningoencephalitis presenting as a stroke. The need for performing a CSF examination on young patients presenting with a cerebrovascular event, and the aggressive investigation of unexplained hypoglycorrhachia are emphasized.
Transcranial Doppler in cerebrovascular disease.
Authors: Wechsler L R , Ropper A H , Kistler J P
Published: June 2011

Doppler analysis of flow in intracranial arteries is now possible using a 2 MHz probe allowing sufficient penetration of bone to obtain signals noninvasively. Thirty-two normal subjects, and 11 patients with cerebrovascular diseases including vasospasm following subarachnoid hemorrhage, middle cerebral artery stenosis, and extracranial internal carotid artery stenosis were studied by transcranial Doppler. Increased peak velocity and spectral broadening of the reflected signal corresponded to clinical and angiographic evidence of middle cerebral artery vasospasm or stenosis. Decreased peak velocity and blunted waveforms occurred in the middle cerebral artery ipsilateral to severe extracranial internal carotid stenosis with poor crossfilling from the contralateral carotid artery. Abnormalities resolved following carotid endarterectomy. Transcranial Doppler identifies vasospasm or stenosis of the middle cerebral artery and may allow noninvasive evaluation of collateral flow across the anterior circle of Willis in patients with extracranial carotid artery stenosis.
Risk factors for spontaneous cerebral hematomas. Case-control study.
Authors: Calandre L , Arnal C , Ortega J F , Bermejo F , Felgeroso B , del Ser T , Vallejo A
Published: June 2011

In a case-control study of 73 cases of cerebral hematoma diagnosed by CT scan, significant risk factors were history of hypertension, chronic alcoholism, evidence of hepatic disease, EKG abnormalities and high hematocrit values. Initial blood pressure was significantly higher in cases, but blood pressure on the third day after admission was not different from controls. Hypertension and alcoholism did not show a clear correlation, but data from other studies explain the role of alcoholism in vascular disease through a relation with high blood pressure. Risk factors were similar in lobar and basal ganglia hematomas.
Restenosis and occlusion after carotid surgery assessed by duplex scanning and digital subtraction angiography.
Authors: Zbornikova V , Elfstrom J , Lassvik C , Johansson I , Olsson J E , Bjornlert U
Published: June 2011

In a study of 140 patients operated upon with 143 carotid endarterectomies (mean follow-up time 5.2 +/- 2.3 years, range 1 month - 9.3 years), vessel morphology was examined with duplex scanning in 113 patients and with digital subtraction angiography (DSA) in 82 patients. The operative mortality was 1.4%; persisting stroke morbidity 3.6% and the combined operative mortality/morbidity 5%. During the follow-up time a further 20 patients (14.5%) died, 13 had new strokes and 14 new TIAs. By life table analysis, the annual rate of stroke including the operative period was 2.7% (1.7% on the operated side and 1.0% on the non-operated side). Fourteen new occlusions (12%) of the operated carotid artery was found and restenosis (greater than 50%) in 13 patients (11.2%). Progression of the atherosclerotic disease in the contralateral non-operated carotid artery was found in 41 patients (37%) including 3 new occlusions. Agreement DSA/duplex was 88% on the operated side and 92% on the non-operated side. New strokes or TIAs on the operated side were more common in patients with occlusions or restenosis (p less than 0.05), whereas no symptoms were referable to occlusions on the non-operated side. Risk factor analysis revealed an increased risk of atherosclerotic progression on the non-operated side in smokers and those with two or more risk factors. The risk of restenosis in the operated carotid artery was higher in females (p less than 0.025).
Effect of the ganglioside GM1, on cerebral metabolism, microcirculation, recovery kinetics of ECoG and histology, during the recovery period following focal ischemia in cats.
Authors: Tanaka K , Dora E , Urbanics R , Greenberg J H , Toffano G , Reivich M
Published: June 2011

The effect of the ganglioside GM1 on the recovery of local cerebral glucose metabolism (lCMRgl), recovery kinetics of cerebrocortical electrical activity, cerebral blood flow and redox state as well as histological changes following focal ischemia has been studied in the cat. Ischemia was produced by occlusion of the left middle cerebral artery (MCA), and GM1 (30 mg/kg) was injected intravenously at 30 min after the MCA occlusion or at the time of release of the occlusion, at 120 min. Another group of animals were subjected to the same ischemic insult, but without GM1 treatment, and sham-operated treated and not treated cats were also studied. The animals of both GM1-treated and non-treated stroke groups were classified into 2 groups (severe and moderate) depending on the depression of electrocortical activity in the ischemic hemisphere at 30 min of the ischemia. There was a significant increase in local cerebral blood flow in the ischemic area in the treated animals. Additionally there was a significant treatment effect on the left peripheral MCA territory for lCMRgl in the 30 min treated moderate group, (p less than .05). This group of animals showed decreased lCMRgl accompanied by less severe histological damage suggesting that GM1 may produce metabolic depression so as to maintain a normal flow-metabolism couple and prevent ischemic structural damage. The possible mechanism of metabolic depression induced by GM1 is briefly discussed.
Inhibition of thromboxane A2 production does not improve post-ischemic brain hypoperfusion in the dog.
Authors: Prough D S , Kong D , Watkins W D , Stout R , Stump D A , Beamer W C
Published: June 2011

In a canine model of global brain ischemia, six dogs received a selective thromboxane A2 synthetase inhibitor, UK 38,485 (dazmagrel) before the ischemic event; six received a saline placebo. Cerebral blood flow (CBF), systolic and diastolic arterial pressure, cardiac output, pH, PaCO2, PaO2, and arterial and jugular-vein thromboxane B2 (a stable metabolite of thromboxane A2) and 6-keto PGF1 alpha (a stable metabolite of prostacyclin) were measured at baseline, after release of aortic and venae caval occlusion and at intervals up to 120 min thereafter. Treated animals showed nearly complete post-ischemic inhibition of thromboxane B2 production; control animals showed increases in jugular venous thromboxane B2. Arterial and jugular venous levels of 6-keto PGF1 alpha were significantly higher in treated animals at most post-ischemic intervals. CBF in both groups was similar to baseline values at time 0, then declined similarly in both groups by 30 min to approximately equal to 35% of baseline values where it remained thereafter. There were no significant differences in other variables at any interval. We conclude that inhibition of thromboxane A2 production does not alter post-ischemic brain hypoperfusion.
Failure of deferoxamine, an iron chelator, to improve neurologic outcome following complete cerebral ischemia in dogs.
Authors: Fleischer J E , Lanier W L , Milde J H , Michenfelder J D
Published: June 2011

Eleven minutes of complete cerebral ischemia was produced in 17 dogs by temporary ligation of the venae cavae and aorta. Immediately prior to the ischemic episode, 7 dogs received deferoxamine, an iron chelator, 50 mg/kg i.v., and 10 dogs received an equivalent volume of saline placebo i.v. Five dogs failed to meet preestablished protocol criteria and were excluded from data analysis. Neurologic recovery was evaluated by an observer blind to the treatment groups in the remaining 12 dogs at 48 hours postischemia. The neurologic effects of complete cerebral ischemia were compared between dogs treated with deferoxamine and those receiving placebo treatment. One of 6 deferoxamine-treated dogs was normal and 5 were moderately to severely damaged. Similarly, 1 of 6 placebo-treated dogs was normal and 5 were moderately to severely damaged. The authors conclude that deferoxamine does not provide cerebral protection in this model of complete cerebral ischemia.
The social and functional consequences of stroke for elderly patients.
Authors: Silliman R A , Wagner E H , Fletcher R H
Published: June 2011

This study sought to answer questions about the social and functional consequences of stroke for elderly patients (greater than or equal to 65 years of age). Survivors of acute stroke were retrospectively identified, and hospital records were reviewed. One year after discharge, follow-up interviews were conducted with families of surviving patients. Most patients were discharged to home (82%) and remained there. Independent functional status was the single predictor of discharge to home (p less than 0.01). By the time of followup, less than half of the surviving patients were functionally independent (42%). Stroke is an important cause of functional dependence among the elderly. Attention should be focused on minimizing the effects of persisting dysfunction on them and their families.
Elevated blood ketone and glucagon levels cannot account for 1,3-butanediol induced cerebral protection in the Levine rat.
Authors: Lundy E F , Klima L D , Huber T S , Zelenock G B , D'Alecy L G
Published: June 2011

1,3-Butanediol is an ethanol dimer that induces systemic ketosis. It has previously been shown to increase hypoxic survival time and reduce neurologic deficit in several experimental preparations. The aim of this study was to determine if the mechanism of 1,3-butanediol-induced cerebral protection was elevation of blood ketone levels, blood glucagon levels, or both. Blood beta-hydroxybutyrate levels, glucagon levels, or both produced by a previously reported protective dose of 1,3-butanediol (47 mmol/kg) were simulated by direct i.v. infusion of the ketone beta-hydroxybutyrate and glucagon separately and in combination, and the effect on hypoxic survival time in instrumented Levine rats (unilateral carotid ligation and hypoxic exposure) was determined. To test if the mechanism was a direct or osmotic effect of the alcohol, an equimolar dose of ethanol (47 mmol/kg) was administered and the effect on hypoxic survival time was compared with that produced by 1,3-butanediol. As in previous studies, 1,3-butanediol significantly increased hypoxic survival time (241% of control, Scheffe p less than 0.05). Various doses of beta-hydroxybutyrate and glucagon were infused to approximate the blood levels of beta-hydroxybutyrate and glucagon produced by a protective dose of 1,3-butanediol. Although beta-hydroxybutyrate or glucagon infusions produced blood levels of these substances that were comparable with those produced by administering butanediol, they failed to prolong hypoxic survival time as long as 1,3-butanediol. No correlation was detected between hypoxic survival time and blood levels of beta-hydroxybutyrate, glucagon, insulin, or glucose. An equimolar dose of ethanol did not significantly increase hypoxic survival time.(ABSTRACT TRUNCATED AT 250 WORDS)
Density of sympathetic nerve terminals in human superficial temporal arteries: potassium permanganate fixation and monoamine oxidase histochemistry.
Authors: Oka N , Akiguchi I , Matsubayashi K , Kameyama M , Maeda T , Kawamura J
Published: June 2011

The density of sympathetic nerve terminals in human superficial temporal arteries from 5 cases at intra- and extracranial bypass surgery was examined with two histochemical methods, one with potassium permanganate fixation and the other with the new monoamine oxidase staining technique. By potassium permanganate fixation, small cored vesicles containing fibers of noradrenergic nerve terminals made up 29.2% of all nerve fibers in the adventitia. The monoamine oxidase-containing nerves in the adventitia made up 31.4%. According to this study, sympathetic nerve terminal density in human superficial temporal arteries was assumed to consist of approximately 30% of all adventitial nerve terminals. In periadventitial nerve bundles, some unmyelinated axons contained monoamine oxidase activity. Thus, staining is considered to be useful in demonstrating the periadventitial and intervaricose fibers as well as the nerve terminals of sympathetic nerves in human cerebral arteries.
Effect of 5-minute ischemia on regional pH and energy state of the gerbil brain: relation to selective vulnerability of the hippocampus.
Authors: Munekata K , Hossmann K A
Published: June 2011

Adult male gerbils were submitted to 5-minute cerebral ischemia by bilateral carotid artery occlusion. At the end of ischemia and at various recirculation times ranging from 15 to 120 minutes, brains were frozen in situ and the regional distribution of ATP, glucose, and tissue pH was studied on coronal cryostat sections by bioluminescent and fluoroscopic techniques. During ischemia ATP was completely depleted, glucose decreased to less than 10% of control, and regional tissue pH decreased from 7.04-7.09 to about 6.0. After the beginning of recirculation tissue pH and the regional content of metabolites exhibited a triphasic course. After 15 minutes pH returned to or even above normal, and ATP- and glucose-induced bioluminescence normalized. However, there was a secondary deterioration of both tissue acidosis and the metabolic state after 30 minutes. After longer recirculation times changes again improved and returned to normal within 2 hours. These changes were similar in all brain regions with the exception of the CA1 sector of the hippocampus, where the transient normalization of tissue pH was absent after 15 minutes of recirculation. This finding is in line with the previously observed microcirculatory insufficiency of this area and demonstrates that the CA1 sector of the hippocampus suffers more pronounced postischemic acidosis than other less vulnerable regions of the brain.
Immunohistochemical characterization of the amyloid deposits and quantitation of pertinent cerebrospinal fluid proteins in hereditary cerebral hemorrhage with amyloidosis.
Authors: Löfberg H , Grubb A O , Nilsson E K , Jensson O , Gudmundsson G , Blöndal H , Arnason A , Thorsteinsson L
Published: June 2011

Cystatin C, a protein inhibitor of lysosomal cysteine proteinases, was demonstrated by immunohistochemical techniques to be present in the birefringent amyloid deposits of the small arteries in the cerebrum, cerebellum, and leptomeninges of 10 Icelandic individuals with hereditary cerebral hemorrhage with amyloidosis. Specimens from other organs were investigated in one of the patients, and amyloid angiopathy characterized by an immunoreactivity of cystatin C was found in a submandibular lymph node. No immunoreactivity of amyloid fibril protein AA, kappa or lambda immunoglobulin light chain, or prealbumin was observed. Significantly low cerebrospinal fluid concentrations of cystatin C were found in all 9 investigated individuals with hereditary cerebral hemorrhage with amyloidosis. The concentrations of beta 2-microglobulin, albumin, and IgG in the cerebrospinal fluid were within normal limits. Isoelectric focusing showed that cystatin C from the cerebrospinal fluid of 9 patients with hereditary cerebral hemorrhage with amyloidosis had an isoelectric point identical to that of normal individuals. This investigation demonstrates that hereditary cerebral hemorrhage with amyloidosis may be diagnosed by two laboratory methods: immunohistochemical investigation of cystatin C in brain tissue specimens and quantitation of cystatin C in cerebrospinal fluid.
Cholinergic cerebral vasodilator effect of ketamine in rabbits.
Authors: Reicher D , Bhalla P , Rubinstein E H
Published: June 2011

To analyze the mechanism of the cerebral vasodilator effect of ketamine in anesthetized rabbits, we measured the internal carotid blood flow with an electromagnetic flowmeter, the arterial pressure, intracranial pressure, end-tidal CO2, and the electroencephalogram. Ketamine injection (1 mg/kg) induced a significant cerebral vasodilatation that was blocked by scopolamine, a cholinergic antagonist. In contrast, the increase in cerebral blood flow after ketamine was additive to the cerebral vasodilator actions of inhaled CO2 and of physostigmine infusion, two procedures that activate cholinergic mechanisms. These observations suggest that in rabbits, ketamine activates a cholinergic cerebral vasodilator system.
Quantitative measurement of blood flow velocity in feline pial arteries during hemorrhagic hypotension and hypercapnia.
Authors: Kobari M , Gotoh F , Fukuuchi Y , Tanaka K , Suzuki N , Uematsu D
Published: June 2011

Due to methodologic difficulties, few investigations have been made on the blood flow velocity in the cerebral microcirculation. Using a newly developed video camera method, we simultaneously measured the blood flow velocity and diameter of pial arteries during hemorrhagic hypotension, after blood pressure recovery, and during CO2 inhalation in cats. When the mean arterial blood pressure was lowered from 129.7 +/- 6.6 to 71.5 +/- 4.1 mm Hg, the blood flow velocity inevitably decreased from 36.6 +/- 5.3 to 27.0 +/- 3.9 mm/sec (p less than 0.001). The calculated blood flow rate [pi X (diameter/2)2 X flow velocity] was preserved in cases with concomitant vasodilation. Conversely, the blood flow velocity increased from 25.3 +/- 5.1 to 31.0 +/- 5.4 mm/sec (p less than 0.001) after mean arterial blood pressure recovery from 67.1 +/- 3.7 to 129.8 +/- 5.8 mm Hg. The blood flow rate was again preserved in vessels with a vasoconstrictive response. Each pial artery apparently dilated or constricted in proportion to the decrease or increase in flow velocity during blood pressure changes, maintaining a constant cerebral blood flow. This indicated the importance of the pial arteries in the mechanisms of cerebral blood flow autoregulation. During 5% CO2 inhalation, the blood flow velocity increased markedly from 25.4 +/- 4.6 to 37.2 +/- 10.0 mm/sec (p less than 0.05), while the pial artery diameter (85.0 +/- 13.7 microns) increased by 9.6 +/- 1.5% (p less than 0.01). The increased flow velocity might be attributable to preferential dilatation of small arterioles or intraparenchymal vessels during hypercapnia.(ABSTRACT TRUNCATED AT 250 WORDS)
Atypical progressive stroke syndrome associated with oral contraceptives and cigarette use.
Authors: Levine S R , Knake J E , Young A B
Published: June 2011

We report a case of progressive multifocal intracranial distal arterial branch occlusive disease in a young adult who smoked heavily and used oral contraceptives. The distribution of the angiographic lesions and the associated telangiectasias and rete mirabile resemble Moya-Moya disease except for clearly absent proximal carotid arterial disease. This type of distal multifocal cerebral arterial occlusive pattern appears to be a very rare manifestation of cigarette and oral contraceptive use. The patient has remained without symptoms for greater than 3 years off oral contraceptives and cigarettes and on antiplatelet agents.
Subarachnoid hemorrhage: frequency and severity of cardiac arrhythmias. A survey of 70 cases studied in the acute phase.
Authors: Andreoli A , di Pasquale G , Pinelli G , Grazi P , Tognetti F , Testa C
Published: June 2011

The frequency and severity of cardiac arrhythmias were studied in 70 patients with spontaneous subarachnoid hemorrhage investigated prospectively with 24-hour Holter monitoring. Patients were less than 70 years old and without clinical and/or ECG signs of previous heart disease; Holter monitoring was initiated within 48 hours of subarachnoid hemorrhage. Arrhythmias were detected in 64 of the 70 patients (91%). Twenty-nine of the 70 patients (41%) showed serious cardiac arrhythmias; malignant ventricular arrhythmias, i.e., torsade de pointe and ventricular flutter or fibrillation, occurred in 3 cases. Serious ventricular arrhythmias were associated with QTc prolongation and hypokalemia. No correlation was found between the frequency and severity of cardiac arrhythmias and the neurologic condition, the site and extent of intracranial blood on computed tomography scan, or the location of ruptured malformation. The extremely high incidence of cardiac arrhythmias, sometimes serious, in the acute period after subarachnoid hemorrhage and the absence of clinical and radiologic predictors make systematic continuous ECG monitoring compulsory to improve the overall results of subarachnoid hemorrhage, irrespective of early or delayed surgical treatment.
Beagle pup model of perinatal asphyxia: nimodipine studies.
Authors: Ment L R , Stewart W B , Duncan C C , Pitt B R
Published: June 2011

Calcium antagonists may be of significant benefit in the pharmacotherapy of cerebral ischemia, possibly by improving postischemic cerebral blood flow (CBF). This study evaluated the effects of the calcium antagonist nimodipine on CBF in a newborn beagle pup model of perinatal asphyxia lasting 5 minutes. Immediately after the asphyxial episode, nimodipine (2 micrograms/kg/min) or saline was infused for 10 minutes, following which [14C]iodoantipyrine determinations of CBF were performed. In noninsulted pups, nimodipine caused both significant decreases in CBF to cortical and deep gray structures as well as a decrease in mean arterial blood pressure (MABP) (p less than 0.05). In insulted pups, nimodipine similarly decreased MABP (p less than 0.001) and CBF to cortical and deep gray matter regions. Nimodipine appeared to have no effect on arterial blood gases and EEG tracings in either insulted or noninsulted pups. Although nimodipine may be shown to improve neurologic outcome in asphyxiated newborn infants, the limits of this study do not show the mechanism to be that of improving CBF.
Intracranial hemorrhage and cocaine use.
Authors: Wojak J C , Flamm E S
Published: June 2011

Cocaine use has increased rapidly over the past few years. This has led to an increase in the number and variety of cocaine-related conditions for which medical attention is sought. Among these have been several cases of intracranial hemorrhage. Four cases reported in the literature and 6 from our own institution are presented here. They represent different diagnoses including hemorrhage from aneurysms and arteriovenous malformations, hemorrhage into a tumor, and spontaneous hemorrhage with no underlying lesion with and without preexisting hypertension. Analysis of these cases suggests that the hypertension induced by cocaine secondary to sympathetic stimulation may be the common factor. Cocaine may also cause arterial spasm. Although the pathophysiology has not been entirely resolved, the clinical significance of this association is clear. Intracranial hemorrhage should be considered in the differential diagnosis whenever a patient presents with an acute alteration in neurologic examination associated with cocaine use.
Ultrastructural characteristics of occluded perforating arteries in stroke-prone spontaneously hypertensive rats.
Authors: Tagami M , Nara Y , Kubota A , Sunaga T , Maezawa H , Fujino H , Yamori Y
Published: June 2011

We studied ultrastructurally cerebral perforating arteries in 60 stroke-prone spontaneously hypertensive rats (SHRSP), which were sequentially killed at 4-52 weeks of age before showing symptoms of stroke. Another 24 SHRSP were killed soon after they showed symptoms of cerebral infarction. The initial vascular lesions observed in the asymptomatic group included focal cytoplasmic necrosis in the outer layers of the media. This change progressed to widespread medial necrosis with time. In the infarction group, numerous monocytes were seen adhering to the endothelium of the arteries having advanced medial damage. Following the adherence of monocytes to the endothelium, large amounts of plasma components were visible in the arterial wall. The accumulation of the plasma components (especially fibrin) thickened the wall, narrowed the lumen, and resulted in occlusion. These results suggest that monocytes may affect the endothelium, perhaps disturbing the so-called blood-brain barrier to proteins. The monocytes may therefore be closely related to the occurrence of arterial occlusion with resultant cerebral infarction.