bluuebunny/crossref_metadata_2025 huggingface dataset:
Acadesine Reduces Indium-Labeled Platelet Deposition After Photothrombosis of the Common Carotid Artery in Rats
Authors: Dietrich W. Dalton , Miller Leonard P. , Prado Ricardo , Dewanjee Sumit , Alexis Nancy , Dewanjee Mrinal K. , Gruber Harry
Published: June 2011

Background and Purpose
The adenosine-regulating agent acadesine has been shown to reduce the incidence of myocardial infarction and stroke after cardiopulmonary bypass surgery. The present study examined the effect of acadesine on the accumulation of indium-labeled platelet emboli and infarct size after photothrombosis of the common carotid artery.

Methods
Rats were anesthetized with halothane and preloaded with
111
In-tropolone–labeled platelets (50 to 80 μCi) 30 minutes before nonocclusive common carotid artery thrombosis induced by a rose bengal–mediated photochemical insult. Intravenous infusion of acadesine (0.5, 1, or 2 mg/kg per minute) or vehicle was begun 30 minutes before right common carotid artery thrombosis and continued for an additional 15 minutes. Rats were then killed and brains processed for the autoradiographic quantitation of labeled platelet aggregates. In a separate group of rats, infarct areas and volumes were determined in treated (acadesine 1 mg/kg per minute) (n=9) and nontreated (n=9) rats 7 days after thrombosis.

Results
Although the ratio of right-to-left common carotid artery radioactivity was not affected by treatment, acadesine at 1 and 2 mg/kg per minute significantly decreased (
P
<.01) platelet deposition within the right cerebral cortex, hippocampus, and striatum. For example, within the frontoparietal cortex, numbers of platelet aggregates were 11.8±1.8 (mean±SEM), 6.1±1.4, 2.3±0.6, and 3.2±0.8 in rats infused with vehicle, 0.5, 1, and 2 mg/kg per minute acadesine, respectively. In addition, infarct volume was reduced by 48% in acadesine-treated (1 mg/kg per minute) rats, with a significant reduction in infarct area at the coronal level 3.7 mm anterior to bregma (
P
<.01).

Conclusions
These results support a prophylactic role for acadesine in reducing the accumulation of platelet emboli during vascular thrombosis and subsequent brain infarction. Acadesine treatment in patients at risk for embolic stroke could potentially lead to cerebral protection.
Elevated Transcranial Doppler Ultrasound Velocities Following Therapeutic Arterial Dilation
Authors: Giller Cole A. , Purdy Phil , Giller Angela , Batjer H. Hunt , Kopitnik Tom
Published: June 2011

Background
Elevated transcranial Doppler (TCD) velocities seen after cerebral angioplasty are commonly interpreted as evidence of residual or recurrent stenosis but may conceivably arise from hyperemia and require different clinical management.

Summary of Report
Four cases of abnormally elevated mean TCD velocities obtained after therapeutic arterial dilation with either balloon angioplasty or intra-arterial administration of papaverine are described. In each case, cerebral angiography revealed a dilated vessel, suggesting that hyperemia and impaired autoregulation were the causes of the high velocities.

Conclusions
These examples suggest that high TCD velocities after vessel dilation may be produced by unpredictable amounts of vessel narrowing and flow alteration. Although a normalizing TCD velocity after angioplasty suggests effective vessel dilation, high velocities may be due partly to hyperemia and cannot be interpreted as arising solely from recurrent stenosis.
Hypertension and Diabetes Mellitus as Determinants of Multiple Lacunar Infarcts
Authors: Mast Henning , Thompson John L. P. , Lee Sze-Haur , Mohr J. P. , Sacco Ralph L.
Published: June 2011

Background and Purpose
We investigated the relationship between hypertension, diabetes mellitus, and lacunes.

Methods
From 1237 cases of ischemic stroke in the Stroke Data Bank of the National Institute of Neurological and Communicative Disorders and Stroke, data from 637 patients whose initial computed tomograms showed lacunar (n=184) or nonlacunar infarcts (n=453) were analyzed. The group with lacunar infarcts was further divided into subgroups according to whether the patients had multiple (n=40) or single (n=144) lacunar infarcts. The association of hypertension and diabetes mellitus with lacunar infarcts was investigated using logistic regression models that included age, sex, and cardiac disease. Similar models were used to analyze the effects of diastolic and systolic blood pressure.

Results
Hypertension (odds ratio [OR], 2.5; 95% confidence interval [CI], 1.1 to 6.0) and diabetes (OR, 2.3; 95% CI, 1.1 to 4.5) were significantly related to multiple but not to single lacunes. Cardiac disease was inversely associated with both single and multiple lacunes. Diastolic blood pressure significantly affected the probability of multiple lacunar infarcts (OR, 1.4; 95% CI, 1.04 to 1.9), whereas systolic pressure did not.

Conclusions
There may be etiologically distinct lacunar infarct subgroups, with multiple lacunes being strongly related to hypertension and diabetes mellitus. Other stroke risk factors may be more important in patients with single lacunes. Diastolic rather than systolic pressure seems to be a major determinant of multiple lacunes.
Lateralization of T-Lymphocyte Responses in Patients With Stroke
Authors: Tarkowski Elisabeth , Naver Hans , Wallin B. Gunnar , Blomstrand Christian , Tarkowski Andrzej
Published: June 2011

Background and Purpose
A number of clinical observations indicate that stroke affects the course of immune-mediated diseases by lateralization of the disease manifestations, such as arthritis. The purpose of this study was to assess the impact of early stroke on lateralization of immune responsiveness.

Methods
The delayed-type hypersensitivity (DTH) reaction to purified protein derivative was used as an in vivo measure of antigen-specific T-lymphocyte reactivity. Assessment of axon reflex vasodilatation was simultaneously used to test for cutaneous sympathetic activity.

Results
There were no significant differences with regard to lateralization of DTH reactivity when all stroke patients were tested. However, patients with minor stroke displayed a significant (
P
<.001) decrease of DTH reaction on the paretic side compared with the contralateral side. In contrast, patients with major stroke showed a significant increase (
P
=.022) of DTH reaction on the paretic side. Patients with left hemiparesis had a significantly greater (
P
=.045) DTH response on the affected side than patients with a right hemiparesis. In addition, only the patients with motor deficit but not with sensory deficit or aphasia displayed side differences in DTH responses. When electrically evoked axon reflexes were studied in relation to DTH reactions, a significant correlation (
r
=.64;
P
<.001) was found between side asymmetries of DTH responses and side asymmetries of axon reflexes in an innervated skin area. No similar relation was present in skin areas where cutaneous sympathetic activity had been blocked by regional anesthesia.

Conclusions
Early stroke lateralizes T-cell–mediated cutaneous inflammation. This effect depends on (1) the localization of the brain lesion, (2) the clinical course of the disease, and (3) the presence of motor deficit and may be mediated by (4) alteration of the cutaneous sympathetic nerve traffic.
Preoperative Assessment of the Carotid Bifurcation
Authors: Patel Mahesh R. , Kuntz Karen M. , Klufas Roman A. , Kim Ducksoo , Kramer Jonathan , Polak Joseph F. , Skillman John J. , Whittemore Anthony D. , Edelman Robert R. , Kent K. Craig
Published: June 2011

Background and Purpose
Noninvasive studies are used with increasing frequency to assess the carotid bifurcation before endarterectomy. Therefore, assessment of their diagnostic accuracies is essential for appropriate patient management. We prospectively evaluate two noninvasive tests, magnetic resonance angiography (MRA) and duplex ultrasonography (DU), as potential replacements for contrast arteriography (CA).

Methods
A blinded comparison of three-dimensional time-of-flight (TOF) MRA, two-dimensional TOF MRA, and DU in 176 arteries was performed. CA was used as the standard of comparison.

Results
Three-dimensional TOF MRA had a sensitivity of 94%, a specificity of 85%, and an accuracy of 88% for the identification of 70% to 99% stenosis; two-dimensional TOF MRA had a sensitivity and specificity that were approximately 10% lower than those of three-dimensional TOF MRA. DU resulted in a sensitivity of 94%, a specificity of 83%, and an accuracy of 86%. Combining data from three-dimensional TOF MRA and DU, allowing for CA only for disparate results, yielded a sensitivity of 100%, a specificity of 91%, and an accuracy of 94% among concordant noninvasive tests, with CA required in 16% of arteries. MRA accurately differentiated 17 carotid occlusions from 16 high-grade (90% to 99%) stenoses, whereas with DU two patent arteries were identified as occluded and one occluded artery was identified as patent.

Conclusions
Three-dimensional TOF MRA is the most accurate noninvasive test. Combined use of MRA and DU results in a marked increase in accuracy to a level that obviates the need for CA in a majority of patients.
Photoreactive Flow Changes in the Posterior Cerebral Artery in Control Subjects and Patients With Occipital Lobe Infarction
Authors: Urban P.P. , Allardt A. , Tettenborn B. , Hopf H.C. , Pfennigsdorf S. , Lieb W.
Published: June 2011

Background and Purpose
Photoreactive flow changes of the posterior cerebral artery (PCA) in control subjects and patients with unilateral occipital lobe infarction were investigated to study the hypothesis that occipital lobe infarction of varying extent leads to a reduced visually activated flow increase in the ipsilateral PCA.

Methods
Maximum mean flow velocity (MFV) of the PCA was investigated by transcranial Doppler sonography after photic stimulation of the retina.

Results
In 25 control subjects MFV was increased by 30.6±9.7%. In 13 patients with unilateral occipital lobe infarction the ipsilateral MFV increase was significantly lower than in control subjects. Nine patients with homonymous hemianopsia showed an ipsilateral MFV increase of 3.4±4.1% (
P
<.001) and four patients with incomplete occipital lobe infarction and homonymous quadrantanopsia had an MFV increase of 16.0±12.8% (
P
<.05).

Conclusions
We conclude that photoreactive flow changes of the PCA represent a noninvasive and reliable measure of functional impairment due to occipital infarction.
l
-Deprenyl Reduces Brain Damage in Rats Exposed to Transient Hypoxia-Ischemia
Authors: Knollema Siert , Aukema Walter , Hom Harold , Korf Jakob , Ter Horst Gert J.
Published: June 2011

Background and Purpose
l
-Deprenyl (Selegiline) protects animal brains against toxic substances such as 1-methyl-1,2,3,6-tetrahydropyridine and 6-hydroxydopamine. Experiments were conducted to test whether
l
-deprenyl prevents or reduces cerebral damage in a transient hypoxia/ischemia rat model.

Methods
Rats were treated for 14 days with 2 mg/kg and 10 mg/kg
l
-deprenyl or saline. After surgery a 20-minute hypoxia/ischemia period was induced by simultaneous occlusion of the left common carotid artery and reduction of the percentage of oxygen in the gas mixture to 10%. Rats were killed 24 hours later. Silver staining was used to reveal damage in several brain regions.

Results
In the brain, both
l
-deprenyl dosages reduced damage up to 78% compared with the controls. Total brain damage was decreased from 23%-31% to 5%-9% with the
l
-deprenyl treatment (2 mg/kg: F
1.13
=6.956,
P
<.05; 10 mg/kg: F
1.13
=5.731,
P
<.05). In the striatum, significant treatment effects were found between both the
l
-deprenyl groups (2 mg/kg and 10 mg/kg, respectively) and the saline group (F
1.13
=14.870,
P
<.005; and F
1.13
=8.937,
P
=.01; respectively). In the thalamus, significant treatment effects were seen in the 2-mg/kg
l
-deprenyl group (F
1.13
=11.638,
P
<.005) and the 10-mg/kg group (F
1.13
=8.347,
P
<.05) compared with the control group. No significant damage decrease was seen in the hippocampus and the cortex.

Conclusions
The results show that
l
-deprenyl is effective as a prophylactic treatment for brain tissue when it is administered before hypoxia/ischemia. Mechanisms responsible for the observed protection remain unclear. The regional differences in damage, however, are in accordance with the reported regional increase in superoxide dismutase and catalase activities after
l
-deprenyl treatment, suggesting the involvement of free radicals and scavenger enzymes.
Structure and Function of the Rat Basilar Artery During Chronic Nitric Oxide Synthase Inhibition
Authors: Moreau Pierre , Takase Hiroyuki , Küng Christoph F. , van Rooijen Menno-M. , Schaffner Thomas , Lüscher Thomas F.
Published: June 2011

Background and Purpose
Nitric oxide is an important regulator of vascular tone and may also be implicated in the modulation of vascular growth and structure. This study presents the effects of chronic nitric oxide inhibition, with or without antihypertensive treatment, on the structure and function of the basilar artery in rats.

Methods
Rats were treated for 6 weeks with
N
ω
-nitro-
l
-arginine methyl ester (50 mg/kg per day) alone or in combination with verapamil (100 mg/kg per day) or with trandolapril (1 mg/kg per day). Untreated rats served as controls. The structure and reactivity of perfused and pressurized basilar arteries were analyzed in vitro using a video dimension analyzer.

Results
Systolic arterial pressure increased only in the nitro-arginine–treated group, as did the media-to-lumen ratio of the basilar artery. This structural alteration, which was prevented by verapamil and trandolapril, was mainly due to remodeling and not to growth. Chronic inhibition of the
l
-arginine pathway increased the response of the basilar artery to serotonin, while the opposite was found for endothelin. Verapamil and trandolapril prevented these functional alterations that seemed related to the changes in the vascular structure.

Conclusions
The remodeling and functional alterations of the basilar artery seem to depend mainly on the elevation of arterial pressure with little contribution of the
l
-arginine pathway. Furthermore, nitric oxide does not seem to be implicated in the modulation of normal cerebral vascular growth in vivo. However, hypertension-induced changes in vascular reactivity and structure could alter cerebral blood flow and eventually contribute to the development of stroke in this model of hypertension.
Respiratory Function and Risk of Stroke
Authors: Wannamethee S. Goya , Shaper A. Gerald , Ebrahim Shah
Published: June 2011

Background and Purpose
This report examines the relationship between lung function and risk of major stroke events (fatal and nonfatal).

Methods
We completed a prospective study of 7735 men aged 40 to 59 years at screening selected at random from one general practice in each of 24 British towns.

Results
During the mean follow-up period of 14.8 years, there were 277 major stroke events in the 7650 men with data on forced expiratory volume in 1 second (FEV
1
). After exclusion of 499 men with definite myocardial infarction, stroke, or atrial fibrillation at screening, 7151 men experienced 239 major stroke events. Lower levels of FEV
1
were associated with a significant increase in risk of stroke even after adjustment for age, smoking, social class, physical activity, alcohol intake, systolic blood pressure, antihypertensive treatment, diabetes, and preexisting ischemic heart disease. Relative risk in the low third (<3.10 L) versus high third (>3.65 L) was 1.4 (95% confidence interval, 1.0 to 2.0). The inverse association between FEV
1
and stroke was only apparent in older men, current nonsmokers, hypertensive men, and men with preexisting ischemic heart disease. Lower FEV
1
was associated with higher rates of stroke in hypertensive men irrespective of smoking status. Inclusion of FEV
1
in a risk score for stroke provided only a small increase in the absolute risk or the yield of cases in the top fifth of the score distribution during the follow-up period.

Conclusions
Lower levels of FEV
1
are associated with an increased risk of stroke in those already at high risk, eg, those with ischemic heart disease or hypertension. However, the association is not strong enough to warrant the use of FEV
1
in making clinical decisions regarding the treatment of hypertension as it relates to the prevention of stroke.
Transcranial Doppler Ultrasound in Hypertensive Versus Normotensive Patients After Aneurysmal Subarachnoid Hemorrhage
Authors: Ekelund Anders , Säveland Hans , Romner Bertil , Brandt Lennart
Published: June 2011

Background and Purpose
Arterial hypertension is a negative prognostic risk factor after aneurysmal subarachnoid hemorrhage (SAH). Transcranial Doppler ultrasound is commonly used for measuring blood flow velocities to predict cerebral ischemia due to vasospasm after SAH. Our purpose was to evaluate the influence of arterial hypertension on blood flow velocities in the cerebral circulation after aneurysmal SAH.

Methods
With transcranial Doppler ultrasound we compared the blood flow velocities in matched groups of hypertensive and normotensive patients with aneurysmal SAH. Twenty-four patients with arterial hypertension were examined daily during a 2-week period. As controls, 24 normotensive patients, also with SAH, were matched by age, sex, neurological status, and clinical outcome.

Results
Minimum, mean, and maximum flow velocities in the middle cerebral artery in the hypertensive patients were significantly lower than in the normotensive individuals, with
P
=.02 for minimum,
P
=.02 for mean, and
P
=.02 for maximum. There was no statistical significance for pulsatility index differences in these groups (
P
=.45). Diastolic notch was noted in two of the hypertensive and in six of the normotensive patients.

Conclusions
The results indicate that even moderately increased flow velocities in hypertensive patients may represent significant vasospasm.
Basic Fibroblast Growth Factor Increases Regional Cerebral Blood Flow and Reduces Infarct Size After Experimental Ischemia in a Rat Model
Authors: Tanaka Ryusui , Miyasaka Yoshio , Yada Kenzoh , Ohwada Takashi , Kameya Toru
Published: June 2011

Background and Purpose
The aim of this study was to ascertain whether basic fibroblast growth factors (bFGF) caused reduction in size of cerebral infarcts in Sprague-Dawley rats with experimental ischemia.

Methods
In the first experiment we induced permanent occlusion of the left middle cerebral artery (MCA). Within 5 minutes after MCA occlusion, we infused bFGF (100 ng in 0.1 mL of saline) in the bFGF-treated group (n=14) and 0.1 mL of saline alone in the control group (n=7) into the common carotid artery ipsilateral to MCA occlusion. We harvested the brains 24 hours after MCA occlusion and determined infarct size planimetrically as a percentage of hemisphere size. In the second experiment cerebral blood flow (CBF) was continuously measured for 120 minutes after MCA occlusion in the bFGF-treated group (n=9) and in the control group (n=8) with the use of laser-Doppler flowmetry.

Results
Infarct size in the bFGF-treated group decreased significantly in comparison with that in the control group (repeated-measures ANOVA,
P
<.0001). CBF in the transitional areas between the MCA and the anterior cerebral artery significantly increased in the bFGF-treated group in comparison with that in the control group (repeated-measures ANOVA,
P
<.005). An approximate 58% decrease in infarct size and a 40% increase in regional CBF were seen on bFGF treatment.

Conclusions
The present study suggested that intracarotid administration of bFGF (100 ng) can reduce infarct size after MCA occlusion. It was speculated that the increased CBF in the penumbral areas of MCA may contribute to contraction of infarct size.
Hemodilution Accelerates the Passage of Plasma (Not Red Cells) Through Cerebral Microvessels in Rats
Authors: Lin Shinn-Zong , Chiou Tsorng-Lanng , Chiang Yung-Hsiao , Song Wen-Shen
Published: June 2011

Background and Purpose
Hemodilution lowers the total circulatory red cell mass and blood viscosity and thereby may alter the time of passage of red cells and plasma through cerebral microvessels. This study was designed to clarify this question.

Methods
Adult Wistar-Kyoto rats, aged approximately 32 weeks, were divided into hemodilution and control groups. Local cerebral blood flow and microvascular red cell and plasma volumes in 14 brain structures were measured with the use of [
14
C]iodoantipyrine,
55
Fe-labeled red cells, and [
14
C]inulin, respectively.

Results
In the control group, the hematocrit in cerebral microvessels ranged from 0.29 to 0.45 with a mean of 0.36, which was 71% of the systemic hematocrit (0.51). The mean transit times of blood, red cells, and plasma through microvessels were 0.62 to 1.77 seconds (mean, 0.92 second), 0.44 to 1.15 seconds (mean, 0.65 second), and 0.78 to 2.5 seconds (mean, 1.25 seconds), respectively. In the hemodilution group, the mean hematocrit in microvessels was 0.28, which was 89% of the systemic hematocrit (0.32). Local cerebral blood flow was approximately 59% higher (
P
<.01) than that of the control animals. The rate of oxygen delivered to the brain was slightly increased (9%) after hemodilution. Blood volume in cerebral microvessels was similar to that of the control group. Mean transit time of blood was 0.62 second (68% of the control), transit time of red cells was 0.53 second (85% of the control), and transit time of plasma was 0.67 second (54% of the control).

Conclusions
These findings indicate that isovolemic hemodilution accelerates the plasma (not red cell) flow velocity in cerebral microvessels.
Prediction of Reflex Sympathetic Dystrophy in Hemiplegic Patients by Electromyographic Study
Authors: Cheng Pao-Tsai , Hong Chang-Zern
Published: June 2011

Background and Purpose
This study was designed to investigate the correlation between reflex sympathetic dystrophy syndrome (RSDS) in hemiplegic patients and spontaneous electromyographic (EMG) activity, as well as to determine the predictive value of spontaneous EMG activity in early diagnosis of RSDS.

Methods
An EMG and nerve conduction velocity study of the weak upper limb was conducted on 70 hemiplegic patients at 3 to 4 weeks after cerebrovascular disease (either cerebral hemorrhage or infarction). Clinical assessment for development of the RSDS was done during the following 6 months. The correlation of RSDS development with the presence of spontaneous EMG activity and certain clinical parameters (including sex, age, side affected, cause of stroke, sensory impairment, spasticity, and shoulder subluxation) was analyzed statistically.

Results
Of the 46 patients who exhibited spontaneous activity, 30 (65%) developed clinical RSDS in their hemiplegic upper extremity, whereas only 1 (4%) of the other 24 patients with no spontaneous EMG activity developed clinical RSDS within 6 months after the onset of hemiplegia (
P
<.001). The correlation of RSDS development with the presence of shoulder subluxation and sensory impairment in the hemiplegic side was statistically significant. Neither age, sex, severity of spasticity, nor etiology of stroke had a significant correlation with the development of clinical RSDS.

Conclusions
There is significant correlation between the presence of spontaneous EMG activity and the development of clinical RSDS in the hemiplegic upper extremity after stroke. It is concluded that spontaneous EMG activity in the hemiplegic hands of stroke patients might be a good predictor of the future development of clinical RSDS.
HU-211, a Novel Noncompetitive
N
-Methyl-
d-
Aspartate Antagonist, Improves Neurological Deficit and Reduces Infarct Volume After Reversible Focal Cerebral Ischemia in the Rat
Authors: Belayev Ludmila , Busto Raul , Zhao Weizhao , Ginsberg Myron D.
Published: June 2011

Background and Purpose
HU-211 is a nonpsychotropic cannabinoid analogue that has been shown to act as a functional
N
-methyl-
d
-aspartate receptor blocker. We investigated the neuroprotective efficacy of HU-211 in a model of reversible middle cerebral artery occlusion (MCAo) in rats.

Methods
Male Wistar rats were anesthetized with halothane and subjected to 90 minutes of temporary MCAo by retrograde insertion of an intraluminal nylon suture, coated with poly-
l
-lysine, through the external carotid artery into the internal carotid artery and MCA. The drug (HU-211 in cosolvent, 4 mg/kg IV) or vehicle was administered in a blinded fashion 70 minutes after onset of MCAo. Behavioral tests were evaluated during occlusion (60 minutes) and for a 3-day period after MCAo. Three days after MCAo, brains were perfusion-fixed, and infarct volumes were determined.

Results
HU-211 significantly improved the neurological score compared with vehicle during the 3 days after MCAo. Treatment with HU-211 also significantly reduced both infarct volume (mean±SEM, 66.6±12.5 versus 149.8±36.3 mm
3
) and brain swelling (2.61±1.33% versus 6.66±1.24%) compared with vehicle-treated rats (n=17 in each group).

Conclusions
These results demonstrate the neuroprotective ability of HU-211 in focal cerebral ischemia as judged by neurological score, infarct size, and brain swelling. Reversible MCAo with the use of a poly-
l
-lysine–coated intraluminal suture proved to be a reliable and effective modification of this technique, yielding consistent results.
Perfusion Imaging of the Brain by B-Mode Ultrasonography
Authors: Itoh Taiji , Matsumoto Masayasu , Uchimoto Ryoko , Takahashi Natsuko , Niwa Kazuo , Handa Nobuo , Tsukamoto Yoshitane , Miyazawa Tomoaki , Kamada Takenobu
Published: June 2011

Background and Purpose
The purpose of this study was to assess the ultrasonic imaging of normal rabbit brain by using echocontrast enhancer to identify the brain tissue perfusion.

Methods
A solution of SH/TA-508 (containing microbubbles of mean size 2 to 4 μm; n=4) was used for contrast enhancement of rabbit brain tissue and was administered through the left internal carotid artery. Contrast enhancement in the ipsilateral parietal area was examined by placing a 7.5-MHz transducer on the dura after a craniectomy. Throughout the experiment, we measured parameters including arterial blood pressure, arterial blood gases, and serum glucose and hematocrit levels. We investigated whether the administration of an echocontrast enhancer would be safe for the brain tissue (n=4).

Results
After injection of 100 mg/mL SH/TA-508, contrast enhancement was clearly observed within approximately 1 second in the left hemisphere (especially in the left cerebral cortex) in all animals and disappeared within 3 seconds after the end of injection. All physiological parameters remained within the normal range throughout the experiment. No focal abnormalities were observed on hematoxylin-eosin staining of the brain tissue.

Conclusions
Contrast enhancement was observed in the ipsilateral hemisphere with the administration of SH/TA-508. Contrast enhancement on B-mode brain imaging would be useful for real-time identification of brain tissue perfusion and should become a promising method for bedside clinical assessment of brain tissue perfusion.
Effect of Acetazolamide on Regional Cerebral Oxygen Saturation and Regional Cerebral Blood Flow
Authors: Kaminogo Makio , Ichikura Akio , Shibata Shobu , Toba Tamotsu , Yonekura Masahiro
Published: June 2011

Background and Purpose
To verify whether the monitoring of regional cerebral oxygen saturation (rSO
2
) with transcranial near-infrared spectroscopy would successfully reflect changes in intracranial hemodynamics but not changes in extracranial compartment, we measured rSO
2
and regional cerebral blood flow (rCBF) simultaneously in seven patients with cerebral ischemia and five normal volunteers before and after acetazolamide administration.

Summary of Report
The baseline values of rSO
2
and rCBF were 64.2±5.6% and 53.9±11.1 mL/100 g per minute, respectively. rCBF increased by 44.4±23.3% and rSO
2
significantly increased to 69.6±5.6% after acetazolamide administration. Bilateral simultaneous measurement of rSO
2
indicated a tendency that the larger the ΔrSO
2
, the greater the Δ%rCBF. The relationship between rSO
2
level and rCBF value fit significantly on the theoretical curve calculated from Fick’s equation.

Conclusions
It is suggested that monitoring of rSO
2
with INVOS-3100 could be a useful indicator in the evaluation of intracranial hemodynamic changes.
Leptomeningeal Dissemination of Malignant Glioma Simulating Cerebral Vasculitis
Authors: Herman Christopher , Kupsky William J. , Rogers Lisa , Duman Ralph , Moore Patricia
Published: June 2011

Background
The complex clinical and radiological picture of leptomeningeal spread of tumor is well recognized as a problem of systemic cancer but is less frequent in primary cerebral glioma, particularly as a presenting picture. While brain ischemia and infarction may occur in patients with subarachnoid tumor, the mechanism for these complications remains unclear. Angiographic and pathological demonstrations of direct vascular involvement by disseminated glioma are particularly sparse. We report a patient presenting with multiple infarctlike lesions with postmortem evidence of direct vascular involvement by glioma.

Case Description
A 54-year-old woman presenting with seizures, headache, and changes in mental status was found to have vascular narrowing in cerebral blood vessels and ischemic lesions on neuroimaging studies of the brain, interpreted as cerebral vasculitis. A brain biopsy showed leptomeningeal glioma. Postmortem examination demonstrated a glioblastoma arising around the right sylvian fissure with extensive subarachnoid dissemination of tumor. The leptomeningeal tumor caused vascular narrowing by encasement, direct vascular wall invasion, and thrombosis and was associated with underlying infarctlike foci of parenchymal necrosis.

Conclusions
This case demonstrates an unusual presentation of glioblastoma clinically and radiographically mimicking cerebral vasculitis, and it illustrates a variety of mechanisms for tumor-produced vascular compromise.
Transcranial Doppler Sonography and Magnetic Resonance Angiography in the Assessment of Collateral Hemispheric Flow in Patients With Carotid Artery Disease
Authors: Anzola G. P. , Gasparotti R. , Magoni M. , Prandini F.
Published: June 2011

Background and Purpose
The aim of this investigation was to compare the respective efficacy of transcranial Doppler sonography (TCD) and magnetic resonance angiography (MRA) for the assessment of intracranial hemodynamics in patients with extracranial occlusion or severe stenosis of the internal carotid artery (ICA).

Methods
Twenty-five patients with unilateral ICA occlusion (n=20) or tight stenosis (n=5) demonstrated by duplex scanning or angiography were studied with both TCD and MRA. Three-dimensional time-of-flight MRA was used for the evaluation of extracranial-intracranial ICAs. Collateralization through the circle of Willis was investigated by means of selective two-dimensional MRA with presaturation of the carotid siphon, ophthalmic artery, or basilar artery. TCD was performed according to published standards: Anterior, middle, and posterior cerebral arteries were insonated through the temporal window, and carotid siphon and ophthalmic artery were assessed through a transorbital approach. Collateralization through the anterior circle of Willis was assumed if anterior cerebral artery flow was reversed, through the external carotid artery if ophthalmic artery flow was reversed, and through the basilar artery if the ratio of ipsilateral to contralateral posterior cerebral artery velocity was greater than 50%. TCD and MRA were performed by different investigators unaware of the results obtained with the other technique.

Results
In every case time-of-flight MRA demonstrated the ICA occlusion or stenosis. There was an excellent correlation (κ=0.64) between TCD and MRA in assessing the hemodynamic contribution of the anterior part of the circle of Willis, whereas MRA was unable to detect the anastomotic pathway of the ophthalmic artery (κ=0.32). The contribution of the posterior communicating artery was difficult to assess with both techniques, but in three cases only MRA showed unequivocal evidence of collateralization. In three cases of middle cerebral artery stenosis TCD was superior to MRA in demonstrating the patency of the vessel.

Conclusions
TCD and MRA should be considered complementary techniques. Combining the findings of both examinations may help to better understand the changes in intracranial hemodynamics produced by extracranial carotid occlusion. The contribution of the ophthalmic pathway, although important for the intraorbital structures, is probably of limited functional significance to the hemispheric blood supply.
Carotid Stenosis Index
Authors: Bladin C.F. , Alexandrov A.V. , Murphy J. , Maggisano R. , Norris J.W.
Published: June 2011

Background and Purpose
Current methods of measuring carotid stenosis such as those used in the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and European Carotid Surgery Trial (ECST) have limitations caused by difficulties in measuring the normal width of the distal internal carotid artery (ICA) or the carotid bulb.

Methods
We developed a new technique, the Carotid Stenosis Index (CSI), based on the known anatomic relationship between the common carotid artery (CCA) and ICA (1.2×CCA diameter=proximal ICA diameter). The normal ICA diameter can therefore be calculated from direct measurement of the CCA. Three blinded observers evaluated the angiograms of 57 patients (114 carotid arteries), previously screened with duplex ultrasonography, using the NASCET, ECST, and CSI methods. In a subset of 30 patients undergoing carotid endarterectomy, comparison was also made to computerized carotid plaque planimetry.

Results
The NASCET method could only be applied correctly in 89% and the ECST method in 95% of cases because of overlying vessels or inadequate views of the distal ICA or carotid bulb. An additional 9% of NASCET cases had a “negative” stenosis, in which the stenosis is wider than the distal ICA. The CSI method was applicable in 99% of cases. Interobserver comparison using ANOVA revealed significant differences using NASCET (
P
<.0001) and ECST (
P
<.001) but not CSI (
P
=NS). NASCET had a sevenfold variation (
P
<.01) and ECST a twofold variation (
P
<.01) in results compared with CSI . The intraobserver reliability was 0.87 for NASCET, 0.86 for ECST, and 0.90 for CSI. However, the 95% confidence intervals for an individual measurement by an observer were ±30% for NASCET, ±19% for ECST, and ±15% for CSI. With linear methods of measurement there were significant differences between NASCET and CSI (
P
<.0001) and ECST (
P
<.0001) but not between CSI and ECST. A comparison of area derivations of these methods to carotid plaque planimetry revealed significant differences from NASCET (
P
<.0001) but not ECST, CSI, or duplex methods. A CSI nomogram was created, allowing measurement of both linear and area percent stenosis.

Conclusions
CSI is the most reliable validated method of measuring carotid stenosis, and it correlates with duplex and carotid pathology.
Impact of Race and Ethnicity on Ischemic Stroke
Authors: Zweifler Richard M. , Lyden Patrick D. , Taft Barbara , Kelly Nancy , Rothrock John F.
Published: June 2011

Background and Purpose
As the US minority population continues to grow, increasing numbers of nonwhite citizens are at risk for stroke. A better understanding of how ischemic stroke differs in the minority populations may lead to more effective clinical management.

Methods
We prospectively evaluated 542 consecutive patients (416 whites, 71 Mexican Americans, 55 blacks) presenting to the University of California at San Diego Medical Center or the San Diego Veterans Affairs Hospital with presumed acute ischemic stroke or transient ischemic attack.

Results
Whites had a higher proportion of transient ischemic attacks (32% versus 18% and 17% for blacks and Mexican Americans, respectively) and had the lowest prevalence of diabetes mellitus (17% versus 29% and 40% for blacks and Mexican Americans, respectively). Mexican Americans had higher initial serum glucose levels (178 versus 133 and 131 mg/dL for whites and blacks, respectively). Blacks were youngest (average age, 56 years). There were no differences among the groups in the prevalence of prior stroke, hypertension, myocardial infarction, or smoking; initial systolic blood pressure, serum cholesterol levels, and functional deficit also were similar. Although it did not reach statistical significance, there was a trend toward relatively late presentation in the black stroke subpopulation: only 53% of blacks (compared with 73% of both Mexican Americans and whites) reached medical attention within 24 hours of stroke onset. All groups had similar diagnostic evaluations and functional outcome at 1 week. With the exception of a higher frequency of stroke of unknown cause in Hispanics, the distributions of stroke etiologies did not differ significantly among the groups.

Conclusions
These data suggest that there are significant clinical differences in populations with ischemic stroke and transient ischemic attack that are related to race and ethnic origin, but in our population these differences did not include the extent of diagnostic evaluation undertaken or stroke severity.
Where and How Should Elderly Stroke Patients Be Treated?
Authors: Kaste Markku , Palomäki Heikki , Sarna Seppo
Published: June 2011

Background and Purpose
Elderly stroke patients in particular are at risk of receiving less than optimal care. We studied the effects of the department care (medicine versus neurology) on the outcome of elderly stroke patients in a randomized controlled trial with 1-year follow-up.

Methods
A total of 243 consecutive patients aged 65 years or older with acute stroke were randomized to receive care in the Departments of Medicine or the Department of Neurology of a university teaching hospital with a referral area of 1.1 million. The outcome was assessed by mortality, length of hospital stay, ability to live at home on discharge, Barthel Index, and Rankin grades at 1 year.

Results
There were no differences in sex and age, severity or type of stroke, other diseases, or social factors between the two groups. One-year mortality was 21% in both patients treated by the Departments of Medicine and those treated by the Department of Neurology. Patients treated by the Department of Neurology were discharged an average of 16 days earlier (24 versus 40 days). The length of hospital stay of patients aged younger than 75 years differed significantly (
P
=.02). Patients randomized to neurological wards more often went directly home (75% versus 62%;
P
=.03), and their functional status was better as assessed with Barthel Index and Rankin grades at 1 year (
P
=.02 and
P
=.03, respectively). Independent predictors of a better functional outcome and shorter hospital stay by stepwise multivariate analysis included management by the Department of Neurology.

Conclusions
Well-organized management of elderly stroke patients was associated with a better outcome. It was also the more economical alternative.
Cat Cerebral Arteries Are Functionally Innervated by Serotoninergic Fibers From Central and Peripheral Origins
Authors: Moreno María Jesús , de Pablo Angel L. López , Conde María Victoria , Marco Emilio J.
Published: June 2011

Background and Purpose
Tryptophan hydroxylase activity and responses to tyramine were analyzed in cat cerebral arteries to investigate serotoninergic innervation.

Methods
Enzymatic activity and responses to tyramine were measured in vessels from animals subjected to cervical gangliectomy and dorsal and median raphe nuclei lesions.

Results
Tryptophan hydroxylase activity in cat cerebral arteries was reduced after ganglia removal and raphe nuclei destruction. Contractile responses of the middle cerebral artery after gangliectomy were decreased by ketanserine. Dorsal raphe nucleus destruction had a significant effect on the contractile response, whereas median raphe nucleus destruction had only a slight effect.

Conclusions
Cat cerebral arteries receive serotoninergic innervation from central and peripheral origins. (Stroke. 1995;26:271-276.)
Dilatation of Cerebral Arterioles in Response to Lipopolysaccharide In Vivo
Authors: Brian Johnny E. , Heistad Donald D. , Faraci Frank M.
Published: June 2011

Background and Purpose
Bacterial lipopolysaccharide can increase nitric oxide (NO) production by expression of an inducible form of NO synthase. Bacterial infections of the central nervous system dilate cerebral vessels and increase blood flow. We hypothesized that topical application of bacterial lipopolysaccharide would increase production of NO, causing dilatation of cerebral arterioles.

Methods
Cranial windows were implanted in anesthetized rabbits. Windows were flushed with artificial cerebrospinal fluid, artificial cerebrospinal fluid with lipopolysaccharide, or artificial cerebrospinal fluid with lipopolysaccharide and
N
G
-monomethyl
-l-
arginine (an inhibitor of NO synthase) for 4 hours. Other rabbits received either dexamethasone or indomethacin intravenously 1 hour before lipopolysaccharide treatment of cranial windows.

Results
Application of lipopolysaccharide in cranial windows produced marked, progressive vasodilatation, with diameter increased by 58±7% (mean±SEM) after 4 hours. The cerebral vasodilator response was inhibited by
N
G
-monomethyl
-l-
arginine, dexamethasone, or indomethacin. Excess
l
-arginine reversed the inhibitory effect of
N
G
-monomethyl
-l-
arginine.

Conclusions
Inhibition of lipopolysaccharide-induced dilatation of cerebral arterioles by
N
G
-monomethyl
-l-
arginine and dexamethasone suggests that a portion of the vasodilatation was mediated by inducible NO synthase. Indomethacin also inhibited lipopolysaccharide-induced vasodilatation. These findings suggest an important role for both nitric oxide and cyclooxygenase products in lipopolysaccharide-induced cerebral arteriolar dilatation in vivo.
N
G
-Nitro-
l
-Arginine Delays the Development of Brain Injury During Focal Ischemia in Rats
Authors: Kozniewska Ewa , Roberts Timothy P. L. , Tsuura Mitsuharu , Mintorovitch Jan , Moseley Michael E. , Kucharczyk John
Published: June 2011

Background and Purpose
The present study was designed to determine the effect of nitro
-l-
arginine, the inhibitor of nitric oxide synthesis, on the evolution of cytotoxic brain edema during focal cerebral ischemia.

Methods
Diffusion-weighted and contrast-enhanced, perfusion-sensitive magnetic resonance imaging was performed in anesthetized, mechanically ventilated rats at 30 minutes and 1, 2, and 3 hours after occlusion of the middle cerebral artery combined with coagulation of the basilar artery. At the onset of ischemia, the animals were infused intravenously with 0.5 mL of either 0.9% NaCl or nitro
-l-
arginine (30 mg/kg). The severity of cytotoxic edema was evaluated based on changes in the water apparent diffusion coefficient (ADC) derived from diffusion-weighted images. The size of the area affected by ischemia was evaluated 3 hours after occlusion using 2,3,5-triphenyltetrazolium chloride (TTC) staining.

Results
The percentage decrease of ADC in the striatum of rats pretreated with nitro
-l-
arginine was significantly smaller (
P
<.05) than in the control group at 30 minutes and 1 and 2 hours of ischemia. The ADC in the injured cortex of nitro
-l-
arginine–treated rats did not differ significantly from the ADC value measured in the contralateral cortex until 3 hours after the occlusion. However, at 3 hours of ischemia the percentage decrease of ADC in both the striatum and the cortex of either group of rats was similar. This transient attenuation of ADC drop during ischemia after nitro
-l-
arginine pretreatment occurred concurrently with a transient improvement of blood supply to the ischemic regions. The percentage of hemispheric area with abnormal TTC staining after 3 hours of ischemia did not differ between control and nitro
-l-
arginine–treated rats.

Conclusions
Nitro
-l-
arginine delays the development of ischemic injury by retarding cytotoxic brain edema. This effect is, at least partially, mediated by an improvement in blood supply to the ischemic tissues.
Transient Increase of Cytokine-Induced Neutrophil Chemoattractant, a Member of the Interleukin-8 Family, in Ischemic Brain Areas After Focal Ischemia in Rats
Authors: Yamasaki Yasundo , Matsuo Yoshiyuki , Matsuura Naosuke , Onodera Hiroshi , Itoyama Yasuto , Kogure Kyuya
Published: June 2011

Background and Purpose
We have indicated that neutrophils play an important role in cerebral ischemia-reperfusion injury. Neutrophils are also known to adhere to the endothelial wall through adhesion molecules and to infiltrate into the tissue, and this neutrophilic invasion correlates with the concentration gradient of chemotactic factors. The aim of the present study was to evaluate the role of cytokine-induced neutrophil chemoattractant (CINC) on brain damage in rats from transient ischemia.

Methods
The brain water content was measured to evaluate postischemic brain injury in rats with 60 minutes of middle cerebral artery occlusion with reperfusion. An enzyme-linked immunosorbent assay was used to evaluate the blood and brain concentrations of CINC, and enzymatic and histological techniques were used to measure the neutrophilic infiltration into the brain.

Results
The increase of water content was first observed at 6 hours after reperfusion, after which this increase was gradual, with brain edema peaking from 24 to 48 hours after reperfusion. Neutrophilic infiltration into the parenchyma and myeloperoxidase activity were first noted 12 hours after reperfusion, after which a marked increase occurred from 24 to 48 hours after reperfusion. In the ischemic brain areas, CINC was first detected at 3 hours after reperfusion. The CINC level peaked at 12 hours after reperfusion (9.15±0.45 ng/g wet wt, n=5) and then gradually reduced from 24 to 48 hours after reperfusion (5.35±0.95 ng/g wet wt, n=5, and 1.25±0.10 ng/g wet wt, n=5, respectively). Interestingly, the serum CINC concentration was transiently elevated from 3 to 6 hours after reperfusion. No CINC production was detected in the brain of rats subjected to 60 minutes of ischemia without reperfusion.

Conclusions
A marked increase in CINC concentration was detected in brain and serum during early reperfusion. This suggests that the time course of CINC production precedes brain edema formation and neutrophilic infiltration. It thus appears that CINC may play an important role in neutrophilic infiltration in ischemic lesion and in brain edema formation after ischemia-reperfusion injury.
Unilateral Upper Limb Asterixis Related to Primary Motor Cortex Infarction
Authors: Nighoghossian N. , Trouillas P. , Vial C. , Froment J. C.
Published: June 2011

Background
Unilateral upper limb asterixis related to cortical infarct is an unusual clinical picture. We found this association in two patients. Magnetic resonance imaging (MRI), somatosensory evoked potentials (SEPs), and electromyographic recording were performed.

Case Descriptions
Two patients developed an acute upper limb ataxia with asterixis. This consisted of frequent arrhythmic loss of extensor muscle tone on instruction to maintain the wrist and fingers extended. Voluntary electromyographic activity in the left extensor digitorum communis muscle showed abrupt periods of interruption ranging from 90 to 260 milliseconds in duration in the first case and from 60 to 220 milliseconds in the second case. SEPs were normal. MRI disclosed a right cortical infarct within the primary motor cortex in both cases.

Conclusions
These findings indicate that asterixis was not related to a failure in the processing of proprioceptive input controlling the regulation of postural tone of the distal upper limbs because SEPs were normal. The involvement of primary motor cortex might suggest that asterixis results from an impairment of a centrally generated motor-command signal controlling the postural tone of the distal upper limb.