bluuebunny/crossref_metadata_2025 huggingface dataset:
Changes in blood flow velocity in the middle cerebral artery during nonpulsatile hypothermic cardiopulmonary bypass.
Authors: Endoh H , Shimoji K
Published: June 2011

We evaluated the utility of blood flow velocity measurements by transcranial Doppler ultrasonography as a tool to indirectly measure cerebral perfusion during cardiopulmonary bypass.

We simultaneously measured blood flow velocity in the middle cerebral artery and physiological variables in 18 patients undergoing cardiac surgery under hypothermic cardiopulmonary bypass in which pH and PaCO2 were managed with the alpha-stat acid-base strategy. We expressed blood flow velocity as a relative value of control obtained under normothermia and normocarbia before bypass. We also developed an original index, modified cerebral metabolic rate for oxygen, to estimate cerebral metabolic rate for oxygen.

Relative velocity was significantly (P < .01) reduced during stable aortic cross-clamp compared with before bypass and was significantly (P < .01) increased during rewarming compared with at aortic cross-clamp. Modified cerebral metabolic rate for oxygen significantly correlated with nasopharyngeal temperature during cooling, aortic cross-clamp, and rewarming (r = .756, P < .0001; r = .4, P < .01; r = .725, P < .0005, respectively). Calculated temperature coefficient for modified cerebral metabolic rate of oxygen was 2.7 +/- 1.4 (mean +/- SD, n = 10) during cooling. Only nasopharyngeal temperature and PaCO2 were significant determinants of relative velocity during aortic cross-clamp.

We can monitor cerebral perfusion and metabolism by measurements of relative velocity and modified cerebral metabolic rate for oxygen during hypothermic cardiopulmonary bypass.
L-arginine infusion promotes nitric oxide-dependent vasodilation, increases regional cerebral blood flow, and reduces infarction volume in the rat.
Authors: Morikawa E , Moskowitz M A , Huang Z , Yoshida T , Irikura K , Dalkara T
Published: June 2011

We previously reported that L-arginine infusion increased pial vessel diameter by nitric oxide-dependent mechanisms, improved regional cerebral blood flow (rCBF) distal to middle cerebral artery (MCA) occlusion, and reduced infarction volume in spontaneously hypertensive rats when administered intraperitoneally before and after MCA occlusion. In this report we extend our findings (1) by examining the time course of L-arginine on rCBF and pial vessel diameter under basal conditions and on rCBF after MCA occlusion and (2) by reproducing the protective effect of L-arginine on infarct volume when given intravenously immediately after the onset of MCA occlusion in both normotensive and hypertensive models of focal cerebral ischemia.

Changes in pial vessel diameter (closed cranial window) and rCBF (laser-Doppler flowmetry) were measured over time after L-arginine infusion into anesthetized Sprague-Dawley rats. rCBF was also measured distal to MCA occlusion in a brain region showing rCBF reductions in the range of 80% of baseline. The effects of infusing L-arginine (300 mg/kg for 10 minutes beginning 5 minutes after occlusion) were assessed on infarction volume in Sprague-Dawley rats after proximal MCA occlusion and in spontaneously hypertensive rats after common carotid artery plus distal MCA occlusion.

L-Arginine (300 mg/kg IV) elevated rCBF by 20% when measured in the dorsolateral cortex of Sprague-Dawley rats and caused L-nitroarginine-methyl ester-inhibitable increases in pial vessel diameter. L-Arginine (> or = 30 mg/kg IV) increased blood flow distal to MCA occlusion by 50%. These effects were sustained throughout the observation period (70 to 105 minutes). Changes in mean arterial blood pressure were not observed. L-Arginine (300 mg/kg IV) reduced infarction volume by 35% and 28% in Sprague-Dawley and spontaneously hypertensive rats, respectively, when examined 24 hours after vessel occlusion.

These studies extend our previous findings by demonstrating that exogenous L-arginine induces sustained rCBF increases in normal brain as well as in a marginally perfused brain region distal to MCA occlusion. Our data in Sprague-Dawley rats support the conclusion that L-arginine-induced increases in rCBF can decrease infarction volume. We conclude that nitric oxide-mediated mechanisms increase rCBF and decrease infarction volume after MCA occlusion in both normotensive and hypertensive animals.
Congenital deficiency of factor VII in subarachnoid hemorrhage.
Authors: Papa M L , Schisano G , Franco A , Nina P
Published: June 2011

Factor VII is essential for coagulation activation by the extrinsic pathway. Hemorrhages of the central nervous system in patients with congenital factor VII deficiency seem to have a higher incidence compared with other congenital coagulopathies. The purpose of this paper is to report two rare cases of subarachnoid hemorrhage and factor VII deficiency.

Two cases of women affected by a congenital deficiency of factor VII and subarachnoid hemorrhage are reported. Diagnosis was obtained by cerebral computer tomography; cerebral pan-angiography was normal. Complete coagulation studies were performed showing prothrombin time prolongation and factor VII deficiency. In one patient, family studies revealed the existence of a similar coagulation disorder.

We suggest routine coagulation studies in all patients with subarachnoid hemorrhage. Determination of factor VII activity might be performed in patients with normal activated partial thromboplastin time and prolonged prothrombin time.
Magnetic resonance imaging study of intracranial vertebrobasilar artery dissections.
Authors: Kitanaka C , Tanaka J , Kuwahara M , Teraoka A
Published: June 2011

The purpose of this study is to demonstrate the magnetic resonance features of intracranial vertebrobasilar artery dissections and to determine the potential and limitations of magnetic resonance imaging in their diagnosis.

We studied five consecutive patients with angiographically verified intracranial vertebrobasilar artery dissection with magnetic resonance imaging (0.5 T) in regard to the shapes of the intramural hematoma and the chronological change of its signal intensity. We also estimated the sensitivity of magnetic resonance imaging for diagnosing dissection.

We observed intramural hematoma in four patients on the first magnetic resonance scan and in all five patients during the course of the study. The shapes of the intramural hematomas were curvilinear, crescentic, "bamboo-cut," "band-like," and spotty. The intensity of the intramural hematoma varied according to its age. On the T1-weighted and the proton images, the intramural hematomas appeared isointense to slightly hyperintense in the first few days and became hyperintense thereafter. The intramural hematomas became isointense or unrecognizable 2 months after onset. The T1-weighted image and the proton images were superior to the T2-weighted image in demonstrating the intramural hematomas.

Magnetic resonance imaging is a sensitive tool for diagnosing intracranial vertebrobasilar artery dissection, particularly in the subacute to early chronic stage. Magnetic resonance imaging is complementary to angiography in that it can directly visualize intramural hematomas.
Prevalence and characteristics of intracranial microemboli signals in patients with different types of prosthetic cardiac valves.
Authors: Georgiadis D , Grosset D G , Kelman A , Faichney A , Lees K R
Published: June 2011

Transcranial Doppler detection of microemboli is widely described, but there is no clear evidence of the clinical significance or nature of the embolic material in vivo. Thromboembolism is a major cause of morbidity in patients with prosthetic cardiac valves. We undertook this study to evaluate the prevalence and the acoustic characteristics of microembolic signals in three groups of patients with different prosthetic valves.

One hundred seventy-nine patients with prosthetic cardiac valves (85 Björk-Shiley, 56 Medtronic-Hall, and 38 Carpentier-Edwards) and 25 normal subjects were examined using transcranial Doppler. Monitoring time was 30 minutes over the right middle cerebral artery.

The prevalence and numbers of embolic signals were significantly higher in patients with Björk-Shiley compared with those with Medtronic-Hall and Carpentier-Edwards valves (89% versus 50% and 53%, respectively; P < .001, chi 2; 156 [112, 204] versus 2 [1, 4] and 2 [1, 4] signals/h, respectively; median [95% nonparametric confidence interval], both P < .001, multiple comparisons, Bonferroni correction). The signal intensity was significantly higher in patients with Björk-Shiley and Medtronic-Hall valves than patients with Carpentier-Edwards valves (2435 [2345, 2527] and 2120 [1745, 2483] versus 225 [184, 287] power units, median [95% confidence interval], both P < .001). No correlation was found between embolic signal numbers and clinical parameters including history of neurological deficit, cardiac rhythm, duration of artificial valve, previous cardiac operations, or intensity of anticoagulation. Embolic signals were not detected in any of the control subjects.

Our data showed that the prevalence, quantity, and acoustic characteristics of Doppler embolic signals differ in patients having three different types of prosthetic heart valves. However, no correlation with clinical parameters was identified.
Detection and volume estimation of embolic air in the middle cerebral artery using transcranial Doppler sonography.
Authors: Bunegin L , Wahl D , Albin M S
Published: June 2011

Cerebral embolism has been implicated in the development of cognitive and neurological deficits following bypass surgery. This study proposes methodology for estimating cerebral air embolus volume using transcranial Doppler sonography.

Transcranial Doppler audio signals of air bubbles in the middle cerebral artery obtained from in vivo experiments were subjected to a fast-Fourier transform analysis. Audio segments when no air was present as well as artifact resulting from electrocautery and sensor movement were also subjected to fast-Fourier transform analysis. Spectra were compared, and frequency and power differences were noted and used for development of audio band-pass filters for isolation of frequencies associated with air emboli. In a bench model of the middle cerebral artery circulation, repetitive injections of various air volumes between 0.5 and 500 microL were made. Transcranial Doppler audio output was band-pass filtered, acquired digitally, then subjected to a fast-Fourier transform power spectrum analysis and power spectrum integration. A linear least-squares correlation was performed on the data.

Fast-Fourier transform analysis of audio segments indicated that frequencies between 250 and 500 Hz are consistently dominant in the spectrum when air emboli are present. Background frequencies appear to be below 240 Hz, and artifact resulting from sensor movement and electrocautery appears to be below 300 Hz. Data from the middle cerebral artery model filtered through a 307- to 450-Hz band-pass filter yielded a linear relation between emboli volume and the integrated value of the power spectrum near 40 microL. Detection of emboli less than 0.5 microL was inconsistent, and embolus volumes greater than 40 microL were indistinguishable from one another.

The preliminary technique described in this study may represent a starting point from which automated detection and volume estimation of cerebral emboli might be approached.
Coexistence of abdominal aortic aneurysm in patients with carotid stenosis.
Authors: Karanjia P N , Madden K P , Lobner S
Published: June 2011

The study was designed to assess the incidence of coexistent abdominal aortic disease in patients with known carotid artery stenosis.

Abdominal ultrasound and physical examination of the abdomen were performed in 89 consecutive patients referred to this tertiary medical center for evaluation of both symptomatic and asymptomatic carotid artery disease. The frequency of abdominal aortic aneurysm detected in this population was compared with that incidentally found in age- and sex-matched patients undergoing abdominal ultrasound for nonvascular reasons.

Eighteen aortic aneurysms were detected by ultrasound in 89 patients with carotid stenosis, compared with three aneurysms in 89 matched patients (P < .01, corrected chi 2). Twelve of the 18 patients with aneurysm had an abnormal abdominal physical examination.

Aortic aneurysm occurs with high frequency in patients with carotid stenosis. Physicians should perform careful abdominal examination on these patients and consider routine abdominal ultrasonic screening.
The influence of age on stroke outcome. The Copenhagen Stroke Study.
Authors: Nakayama H , Jørgensen H S , Raaschou H O , Olsen T S
Published: June 2011

This study was undertaken to elucidate whether and how age influences stroke outcome.

This prospective and community-based study comprised 515 consecutive acute stroke patients. Computed tomographic scan was performed in 79% of patients. Activities of daily living (ADL) and neurological status were assessed weekly during hospital stay using the Barthel Index (BI) and the Scandinavian Stroke Scale (SSS), respectively. Information regarding social condition and comorbidity before stroke was also registered. A multiple regression model was used to analyze the independent influence of age on stroke outcome.

Age was not related to the type of stroke lesion or infarct size. However, age independently influenced initial BI (-4 points per 10 years, P < .01), initial SSS (-2 points per 10 years, P = .01), and discharge BI (-3 points per 10 years, P < .01). No independent influence of age was found regarding mortality within 3 months, discharge SSS, length of hospital stay, and discharge placement. ADL improvement was influenced independently by age (-3 points per 10 years, P < .01), whereas age had no influence on neurological improvement or on speed of recovery.

Age independently influences stroke outcome selectively in ADL-related aspects (BI) but not in neurological aspects (SSS), suggesting a poorer compensatory ability in elderly stroke patients. Therefore, rehabilitation of elderly stroke patients should be focused more on ADL and compensation rather than on the recovery of neurological status, and age itself should not be a selection criterion for rehabilitation.
Cerebellar venous infarction in chronic suppurative otitis media. A case report with review of four other cases.
Authors: Nayak A K , Karnad D , Mahajan M V , Shah A , Meisheri Y V
Published: June 2011

Cerebellar venous infarction is a rare condition. Thus far only four cases have been reported in the literature. We recently encountered a patient with chronic suppurative otitis media complicated by cerebellar venous infarction. The features of cerebellar venous infarction in the other four cases are also reviewed.

A 20-year-old man presented with clinical features suggestive of chronic suppurative otitis media. Computed tomographic scan of the brain revealed left mastoiditis with cholesteatoma and moderate communicating hydrocephalus. The patient was subjected to left radical mastoidectomy, and an attico-antral cholesteatoma was removed. Subsequently the patient developed clinical features suggestive of cerebellar abscess. A repeat computed tomographic scan revealed normal posterior fossa. Four-vessel angiography revealed left sigmoid and lateral sinus thrombosis and nonopacification of the left-sided cerebellar veins. Magnetic resonance imaging showed a venous infarct in the left cerebellar hemisphere. The patient was treated with cerebral dehydration measures. The patient subsequently improved and had no neurological deficit 3 months after surgery.

Although cerebellar venous infarction is rare, it can occur in chronic suppurative otitis media, pregnancy, antithrombin III deficiency, and diabetic osmolar coma. Sometimes no cause is found. Treatment includes correction of the underlying cause. The presence of a hemorrhagic lesion on computed tomographic scan and deep coma at presentation indicate poor prognosis.
Basilar artery occlusion caused by thrombosis of atherosclerotic fusiform aneurysm of the basilar artery.
Authors: Watanabe T , Sato K , Yoshimoto T
Published: June 2011

Basilar artery occlusion caused by thrombosis of atherosclerotic fusiform aneurysm of the basilar artery is rare. We present a case confirmed by 6 years of follow-up and autopsy.

A 63-year-old man suffered from brain stem infarction. Computed tomography and angiography showed a fusiform aneurysm on the proximal portion of the basilar artery. At the time of the third attack 5 years later, complete thrombosis of the aneurysm was found, and the proximal basilar artery was occluded. On autopsy, an atherosclerotic aneurysm 15 mm in diameter was found.

A large atherosclerotic fusiform aneurysm of the basilar artery often causes brain stem infarction and involves a risk of complete thrombosis of the aneurysm and subsequent parent artery occlusion.
Study of antiphospholipid antibodies in a patient with Sneddon's syndrome and her family.
Authors: Lousa M , Sastre J L , Cancelas J A , Gobernado J M , Pardo A
Published: June 2011

Sneddon's syndrome is a disease characterized by livedo reticularis and cerebrovascular lesions, with a hereditary transmission and unknown etiopathogenesis. A number of reports have documented a link between antiphospholipid antibodies and Sneddon's syndrome with different results. The present work was designed to sequentially study antiphospholipid antibodies in a patient with Sneddon's syndrome and her family and their potential role in thrombotic events. We used cardiolipin and a mixture of phospholipids from rabbit brain as antigen for antiphospholipid assays to determine diagnostic usefulness.

A patient with Sneddon's syndrome and 12 available family members belonging to three generations were evaluated to determine the presence of antiphospholipid antibodies (lupus anticoagulant and anticardiolipin antibodies) during vascular thrombotic events and asymptomatic periods.

Our results support a temporal relation between thrombotic events in Sneddon's syndrome and lupus anticoagulant; anticardiolipin antibodies remained invariable. Our index case patient and her father could be diagnosed as having primary antiphospholipid antibody syndrome. Aspirin was not effective in preventing thrombosis. After the onset of oral anticoagulant therapy, no recurrences were seen. The use of a mixture of phospholipids as antigen could present some advantages in serological studies performed in antiphospholipid syndromes.
Cerebral lesions on magnetic resonance imaging, heart disease, and vascular risk factors in subjects without stroke. A population-based study.
Authors: Lindgren A , Roijer A , Rudling O , Norrving B , Larsson E M , Eskilsson J , Wallin L , Olsson B , Johansson B B
Published: June 2011

To assess the prevalence of asymptomatic abnormalities on magnetic resonance imaging of the brain and their possible relation to hypertension, heart disease, and carotid artery disease, we studied 77 randomly selected subjects (mean age, 65.1 years; range, 36 to 95 years) with no history of focal brain lesions.

The study protocol included magnetic resonance imaging of the brain, transthoracic and transesophageal echocardiography, ultrasonography of the carotid arteries, and electrocardiographic recording. Deep and periventricular white matter hyperintensities on magnetic resonance imaging were assessed both separately and together.

On magnetic resonance imaging of the brain 62.3% (95% confidence interval [CI], 51.5% to 73.2%) of the subjects had white matter hyperintensities. These abnormalities increased significantly with age (chi 2 test; P = .0001), from 13.6% (95% CI, 0% to 28.0%) of subjects aged younger than 55 years to 85.2% (95% CI, 71.8% to 98.6%) of subjects aged 75 years or older. Six subjects had deep gray matter hyperintensities localized in the basal ganglia, and one had a cerebellar infarction. Stepwise logistic regression analysis identified age and a history of heart disease (but not echocardiographic findings) to be independently associated with deep and periventricular white matter hyperintensities. Hypertension was only independently associated with periventricular white matter hyperintensities. Of the 68 subjects examined with both transthoracic and transesophageal echocardiography, potential cardioembolic sources were detected in 38.2% (95% CI, 26.7% to 49.8%) of the subjects with transthoracic echocardiography and in 47.1% (95% CI, 35.2% to 58.9%) of those with transthoracic and transesophageal echocardiography combined. In subjects aged 75 years or older, a possible cardiac embolic source was detected in 64.0% on transthoracic echocardiography and in 72.0% on transthoracic and transesophageal echocardiography combined, compared with 5.3% and 15.8%, respectively, in subjects aged younger than 55 years.

White matter hyperintensities and potential cardioembolic sources are frequently present in asymptomatic individuals, stressing the need for age-matched control subjects in studies of patients with stroke or dementia.
Mesial temporal cortex hypoperfusion is associated with depression in subcortical stroke.
Authors: Grasso M G , Pantano P , Ricci M , Intiso D F , Pace A , Padovani A , Orzi F , Pozzilli C , Lenzi G L
Published: June 2011

This study was conducted to evaluate local cerebral blood flow changes in patients with depression after a subcortical stroke.

Clinical and neuropsychological assessments were performed in 15 patients with a single subcortical lesion. Depression was assessed by DSM-III-R. In addition, the Hamilton Rating Scale for depression, the Zung Self-Rating Depression Scale, and the Beck scale were administered to each patient. Single-photon emission-computed tomography study was performed with 99mTc hexamethylpropyleneamine oxime.

In all patients cortical regions ipsilateral to subcortical lesions were significantly less perfused than the contralateral cortex. Cerebral blood flow values were significantly lower in depressed patients (n = 8) than in nondepressed patients (n = 7) only in the mesial temporal cortex of the affected hemisphere. Cerebral blood flow values in the mesial temporal cortex of the affected hemisphere significantly correlated with the severity of depression.

Temporal lobe hypoperfusion may reflect a dysfunction of the limbic system, suggesting that this location may be critical for the occurrence of depressive symptoms in patients with subcortical stroke.
Impact of microembolism and hemodynamic changes in the brain during carotid endarterectomy.
Authors: Jansen C , Ramos L M , van Heesewijk J P , Moll F L , van Gijn J , Ackerstaff R G
Published: June 2011

Monitoring of carotid endarterectomy with electroencephalography and transcranial Doppler ultrasonography provides instantaneous information about hemodynamic changes and embolic signals. However, a relation between these findings and intraoperative infarcts has not yet been demonstrated.

In this study we compared preoperative and post-operative computed tomographic scans (58 patients) or magnetic resonance imaging (40 patients) of the brain, assessed by two independent observers, to detect intraoperative infarcts, and we related any such new lesions to the findings of intraoperative monitoring.

In the computed tomography series one intraoperative infarct occurred, with corresponding clinical deficits. In the magnetic resonance group four patients developed new lesions that occurred intraoperatively, all of which were clinically silent. There was a significant relation between the number of embolic signals during the surgical dissection of the carotid artery and the occurrence of intraoperative infarcts (P < .005). Three of the four infarcts were of the lacunar type; the fourth patient had a border-zone infarct, associated not only with many embolic signals but also with low flow during cross-clamping. There were no demonstrable ultrasound side effects on brain tissue.

Embolic signals detected by transcranial Doppler monitoring in the dissection phase of carotid endarterectomy show a significant relation to new ischemic lesions and therefore are potentially harmful. The phenomenon should alert the vascular surgeon.
Stroke incidence and mortality in rural and urban Shanghai from 1984 through 1991. Findings from a community-based registry.
Authors: Hong Y , Bots M L , Pan X , Hofman A , Grobbee D E , Chen H
Published: June 2011

Mortality from stroke has declined in many countries. This decline may result from a fall in incidence of stroke or a decrease in case fatality from stroke. The present study was conducted to investigate the temporal trends of incidence rate, mortality rate, and case fatality of stroke in an urban and rural Chinese population.

A community-based registry study was established in 1983 in defined rural and urban areas of Shanghai with a population aged 35 to 74 years of approximately 86,000 subjects, adhering to the methods and definitions of the World Health Organization MONICA protocol. All stroke events occurring in the population aged 35 to 74 years in these areas were registered by a special three-level case-registration system.

From 1984 through 1991, 1391 stroke cases were identified. No significant change in the incidence rate of stroke was observed from 1984 through 1991 in men and women living in rural and urban areas. Age-standardized mortality rates (per 100,000 person years) of stroke declined significantly during this period, except for rural women. The annual changes and 95% confidence intervals of age-standardized mortality rates were: for rural men -4.6% (-5.4, -3.9), for rural women -0.6% (-1.6, 0.5), for urban men -2.5% (-3.5, -1.6), and for urban women -4.7% (-5.2, -4.2). A significant decrease in case fatality from stroke from 1984 through 1991 was found among men living in rural areas (from 62.4% to 46.0%) and among women living in urban areas (from 48.4% to 33.3%). Overall case fatality, however, showed a nonsignificant decline over time.

We observed a decline in stroke mortality rate in a rural and urban Chinese population. No significant changes in stroke incidence were found in this study, whereas case fatality appeared to have decreased, in particular among men living in rural areas and women living in urban areas.
Coagulation activity and emboli counts in patients with prosthetic cardiac valves.
Authors: Georgiadis D , Mallinson A , Grosset D G , Lees K R
Published: June 2011

The underlying embolic material detected by transcranial Doppler ultrasound in patients with prosthetic heart valves remains unknown. We undertook this study to evaluate the relation between the number of Doppler emboli signals and the activity of the coagulation system.

Patients with various types of prosthetic valves (n = 120) and patients in atrial fibrillation (n = 20) were monitored for 30 minutes using transcranial Doppler with a 2-MHz probe. The plasma concentrations of cross-linked D-dimer, antithrombin-III, and thrombin-antithrombin III complex were measured.

No correlation between the levels of any of the hematologic parameters and the number of emboli was demonstrated in the studied groups. The D-dimer levels were significantly higher in patients with mechanical prosthetic valves with an international normalized ratio under 2.0 compared with those with an international normalized ratio between 2 and 3.5 or above 3.5, and in patients with Medtronic-Hall versus Björk-Shiley or Carpentier-Edwards valve prostheses.

The lack of correlation between the activity of the coagulation system and the number of Doppler emboli in patients with prosthetic valves suggests that the underlying embolic material in these patients is not thrombotic. Our results also suggest that an increase of the anticoagulation intensity to an international normalized ratio above 3.5 does not result in a further decrease of the activity of the unstimulated coagulation system in patients with mechanical prosthetic valves.
Chimeric 7E3 prevents carotid artery thrombosis in cynomolgus monkeys.
Authors: Rote W E , Nedelman M A , Mu D X , Manley P J , Weisman H , Cunningham M R , Lucchesi B R
Published: June 2011

We compared the current antithrombotic strategy of antiplatelet therapy with aspirin, and anticoagulant therapy with heparin, with a specific genetically engineered chimeric antibody (c7E3 Fab) directed against the human glycoprotein IIb/IIIa receptor in an animal model of arterial thrombosis.

Anesthetized cynomolgus monkeys (Macaca fascicularis) were instrumented for monitoring of arterial blood pressure, heart rate, and carotid artery flow velocity. Animals were treated with saline (n = 6), aspirin (25 mg PO daily for 3 days; n = 6), heparin (100 U/kg i.v. plus infusion adjusted to maintain activated partial thromboplastin time at 2 to 3 times baseline; n = 6), aspirin plus heparin (as administered separately, n = 6), or c7E3 Fab (0.10 mg/kg i.v., n = 7; 0.15 mg/kg i.v., n = 6; 0.20 mg/kg i.v., n = 6; 0.25 mg/kg i.v., n = 6). Thrombus formation via anodal electrolytic stimulation (100 microA) to the intimal surface of the right carotid artery was initiated 15 minutes after drug administration and continued for 180 minutes. Electrolytic injury to the left carotid artery began 210 minutes after drug administration and continued for 180 minutes. Whole blood cell counts, glycoprotein IIb/IIIa receptor blockade, ex vivo platelet aggregation, template bleeding time, and activated partial thromboplastin time were assessed at various time points throughout the experimental protocol.

Hemodynamic and hematologic parameters were comparable among groups at baseline. Treatment with c7E3 Fab inhibited ex vivo platelet aggregation, increased bleeding time, decreased thrombus weight, and increased time to occlusion in a dose-dependent manner in both vessels. Treatment with aspirin, heparin, or the combination of aspirin plus heparin was ineffective for the prevention of carotid artery thrombosis in this model.

Inhibition of the platelet glycoprotein IIb/IIIa receptor with c7E3 Fab was found to be safe and effective for the prevention of primary thrombus formation, whereas treatment with either aspirin or heparin or the combination of the two agents failed to protect against occlusive thrombus formation in cynomolgus monkeys.
Stroke: the way things really are.
Authors: Scheinberg P
Published: June 2011

To comply with governmental requirements regarding the validity of therapeutic modalities and for medico-legal purposes, it is important to distinguish between what has been scientifically proven and what is anecdotal in the prevention and management of stroke.

This review summarizes the evidence for many of the modalities used to prevent stroke in high-risk patients, including antiplatelet drugs, anticoagulants, and endarterectomy, and the limitations of each. Controversial therapeutic modalities for which no scientific proof exists, such as anticoagulation of progressing stroke, are also discussed. The term "standard of care" should apply to modalities proven to be effective by scientifically controlled studies, not because they are used by many physicians. Treatment of acute stroke is still disappointing despite the development of many promising pharmacological strategies in experimental animals. An important part of the reason may be that the window of therapeutic opportunity is much shorter than the usual entry time of patients in most clinical trials. This logistic problem merits serious attention.

Numerous controlled, randomized, multiple-center clinical trials have demonstrated that the efficacy or lack thereof of various therapies directed at preventing or treating stroke can be determined and that anecdotal data may be misleading and harmful. At the least we should be aware of what we know and what we do not.
The impact of microemboli during cardiopulmonary bypass on neuropsychological functioning.
Authors: Pugsley W , Klinger L , Paschalis C , Treasure T , Harrison M , Newman S
Published: June 2011

Microemboli have been implicated in the etiology of neuropsychological deficits after cardiopulmonary bypass. This study examined the incidence of high-intensity transcranial signals (microemboli) and their relation to changes in neuropsychological performance after surgery.

Transcranial Doppler ultrasonography was used to measure middle cerebral artery blood flow velocity and detect microemboli. The number of high-intensity transcranial signals was determined and related to a neurological examination and absolute changes in neuropsychological performance as well as the number of patients considered to exhibit a neuropsychological deficit. Data were available on 100 consenting patients undergoing routine cardiopulmonary bypass. Fifty of the patients were randomly assigned to a procedure that included a 40-microns arterial line filter, and 50 had the procedure without any arterial line filter.

Significantly more patients were found to have neuropsychological deficits in the group without the arterial line filter at both 8 days (P < .05) and 8 weeks (P < .03) after surgery. In addition, more "soft" neurological signs were found in the nonfiltered group 24 hours after surgery (P < .05). More high-intensity transcranial signals were found in the nonfiltered group, and the number of high-intensity transcranial signals was found to be related to the likelihood of a patient having a neuropsychological deficit at 8 weeks.

These data suggest that neuropsychological deficits after routine cardiopulmonary bypass are related to the number of microemboli delivered during surgery. Furthermore, the numbers of microemboli may be reduced by including a 40-microns filter on the arterial line.
Cerebral blood flow in subcortical global aphasia. Perisylvian cortical hypoperfusion as a crucial role.
Authors: Okuda B , Tanaka H , Tachibana H , Kawabata K , Sugita M
Published: June 2011

Global aphasia after subcortical stroke is very rare, and its pathophysiology remains unsolved. To clarify the mechanism underlying subcortical global aphasia, we investigated lesion sites and cerebral blood flow in patients with subcortical global aphasia and nonaphasic patients with subcortical stroke.

We examined four patients with global aphasia and four nonaphasic patients. Language testing was performed more than 4 weeks after the onset. Measurement of cerebral blood flow was done between 35 and 75 days after stroke by using single-photon emission computed tomography (SPECT) with N-isopropyl-p[123I]iodoamphetamine as a tracer and three-dimensional surface display generated from SPECT.

All aphasic patients had subcortical lesions in the putamen, posterior internal capsule, temporal isthmus, and periventricular white matter in the left hemisphere. No cortical lesions were found on either magnetic resonance imaging or computed tomographic scanning. The nonaphasic patients had smaller periventricular white matter lesions and no temporal isthmus lesions. All aphasic patients showed cortical hypoperfusion mainly in the perisylvian areas, including Broca's and Wernicke's areas. In contrast, cortical cerebral blood flow of the nonaphasic patients was decreased in smaller areas and spared the perisylvian language areas.

These results suggest that cortical hypoperfusion in the perisylvian language areas, presumably due to undercutting of the white matter, is crucial for the development of subcortical global aphasia.
Pure sensory stroke caused by a pontine infarct. Clinical, radiological, and physiological features in four patients.
Authors: Shintani S , Tsuruoka S , Shiigai T
Published: June 2011

We conducted this retrospective study to evaluate the clinical, neuroradiological, and neurophysiological findings in patients with pure sensory stroke due to pontine lacuna.

Four patients with pontine lacuna, three men and one woman (mean age, 64.5 years; range, 55 to 75 years), were evaluated. Magnetic resonance images were obtained with a 0.5-T superconducting magnet using the SE technique. Short-latency somatosensory evoked potentials were evaluated by unilateral stimulation of the median nerve at the wrist. These tests were done at a mean of 22.5 months (range, 9 to 34 months) after symptom onset. Deep sensory disturbances were present in one half of the patient's body with no other neurological deficits found. The sensory deficit was characterized by a prolonged period of refractory dysesthesia and a discrepancy between the superficial and deep sensory disturbances. Lesions were localized in the medial lemniscus of the middle and lower pons, with a sparing of the spinothalamic tracts. The central conduction times of short-latency somatosensory evoked potentials were prolonged (patients 1, 2, and 4), and the amplitudes were significantly reduced (patients 1 and 2) when stimulating the paresthetic-sided median nerve (contralateral side of the lesion) compared with stimulating the other side.

In all cases, the clinical and radiological findings indicated a dysfunction of the medial lemniscal tract in the pons. The observed somatosensory evoked potentials were probably related to the persistent refractory dysesthesias present in these patients.
Bilateral occipital infarctions associated with carotid stenosis in a patient with persistent trigeminal artery. The Collaborators of the North American Carotid Endarterectomy Trial (NASCET).
Authors: Gasecki A P , Fox A J , Lebrun L H , Daneault N
Published: June 2011

Embolization via a persistent trigeminal artery, one of the embryonic vascular connections that may persist between the carotid and basilar arteries, is an unusual occurrence.

We describe a 76-year-old man with bilateral occipital infarctions presumably related to an ulcerated left carotid stenosis. Clinically, a left inferior homonymous quadrantanopia was present.

Anomalous connections between the carotid and the usual posterior circulation territory should be considered in evaluating patients with vertebrobasilar stroke. When they are identified, patients with symptoms attributable to the pontine vertebrobasilar territory supplied by the anomaly may be considered for carotid endarterectomy in the presence of concomitant severe carotid stenosis detected angiographically. Proper identification and treatment of such cases would be expected to prevent recurrence of disabling strokes in the vertebrobasilar circulation. These anomalies will likely be overlooked by ultrasound techniques and depend on good intracranial arteriographic images.
Shear-induced platelet aggregation in cerebral ischemia.
Authors: Uchiyama S , Yamazaki M , Maruyama S , Handa M , Ikeda Y , Fukuyama M , Itagaki I
Published: June 2011

Recent evidence has suggested that shear-induced platelet aggregation is an important mechanism of thrombosis at arterial bifurcations or stenoses. We measured shear-induced platelet aggregation with a new apparatus in patients with cerebral ischemia and also studied correlations with other hemostatic parameters as well as the effect of antiplatelet agents.

The subjects were 75 patients with cerebral ischemia and 26 control subjects. Platelet aggregation was induced in citrated platelet-rich plasma by a high shear stress (108 dynes/cm2) that was applied by means of a cone-plate streaming chamber based on turbidimetry. We studied the correlation of test results with hemostatic parameters and also the effects of antiplatelet agents.

Compared with the control subjects, an increase of shear-induced platelet aggregation was observed in 21 patients with atherothrombotic stroke and 12 with transient ischemic attacks, but not in 11 with cardioembolic stroke or 31 with lacunar stroke. There was no significant correlation of shear-induced platelet aggregation with platelet count, agonist-induced platelet aggregation, fibrinogen level, or beta-thromboglobulin level. The extent of shear-induced aggregation was not correlated with von Willebrand factor antigen levels but was significantly correlated with the amounts of larger von Willebrand factor multimers. Oral aspirin (81 mg/d) did not inhibit shear-induced platelet aggregation, whereas oral ticlopidine (200 mg/d) significantly inhibited it.

These results indicate that shear-induced platelet aggregation is increased in patients with atherothrombotic stroke and transient ischemic attacks, is correlated with the increase of larger von Willebrand factor multimers, and is corrected by ticlopidine but not by low-dose aspirin.
Factors affecting changes in blood pressure after acute stroke.
Authors: Harper G , Castleden C M , Potter J F
Published: June 2011

We sought to establish the pattern of blood pressure (BP) change after hospitalization for acute hemispheric stroke.

In 292 patients from the Leicester teaching hospitals with acute hemispheric stroke within the previous 24 hours (139 men; median age, 75 years [range, 42 to 98 years]), we prospectively studied BP changes between admission, 24 hours, 1 week, and 4 to 6 weeks. Changes were assessed in relation to the main stroke risk factors, stroke type and severity, and antihypertensive drug treatment. All subjects were followed up for 1 week, with 117 subjects followed up for 4 to 6 weeks. Changes were assessed by repeated-measures ANOVA, and Student's t tests were used to compare group pairs.

Systolic and diastolic BP fell by 12 mm Hg (95% confidence interval [CI], 8 to 15 mm Hg) and 7 mm Hg (95% CI, 5 to 9 mm Hg), respectively, in the first 24 hours and 22 mm Hg (95% CI, 18 to 25 mm Hg) and 12 mm Hg (95% CI, 10 to 14 mm Hg), respectively, during the first week (all changes significant at P < .01) but no further thereafter. In those patients receiving no antihypertensive medication before or after stroke, the pattern of change was similar to that of the whole group. Previously diagnosed hypertensive subjects (n = 106) had higher initial BP values than did normotensive subjects, although by 1 week the levels were not significantly different. Patients with cerebral hemorrhage confirmed by computed tomography (n = 20) had higher systolic BP, but not diastolic BP, throughout the first week than those with cerebral infarction (n = 89). The severity of stroke, age, and previous stroke history did not appear to alter the BP pattern. Stroke patients who were moderate to heavy alcohol consumers had lower convalescent systolic BP levels than lighter drinkers or abstainers.

We have demonstrated a marked fall in systolic and diastolic BP levels during the first 7 days after acute hemispheric stroke, with little change thereafter. Higher initial systolic BP values were found in patients with cerebral hemorrhage compared with those with cerebral infarct. Moderate to heavy alcohol consumption before stroke was associated with a greater systolic BP decline in the first week after the event compared with stroke patients who were light drinkers or abstainers.
Evaluation of cerebral vasoreactivity by three-dimensional time-of-flight magnetic resonance angiography.
Authors: Mandai K , Sueyoshi K , Fukunaga R , Nukada M , Tsukaguchi I , Matsumoto M , Kamada T
Published: June 2011

Cerebral vasoreactivity is an important indicator of the reserve capacity of the cerebral circulation. To make a quantitative analysis of cerebral vasoreactivity in individual major arterial territories, we evaluated the response to acetazolamide using three-dimensional time-of-flight magnetic resonance angiography.

We examined 10 healthy volunteers and 6 patients with unilateral stenosis of the middle cerebral artery by a 1.5-T superconducting magnetic resonance imaging system. After a baseline vascular image was obtained, each subject received 17 mg/kg IV of acetazolamide; a second scan was performed 20 minutes later. Using a generally available personal computer and image analysis software, we measured the areas of the individual major arteries on collapsed axial vascular images and then calculated the vasoreactivity.

The average vasoreactivity of individual major cerebral arterial territories in the healthy volunteers was as follows: anterior cerebral artery complex, 33%; right middle cerebral artery, 71%; left middle cerebral artery, 74%; right posterior cerebral artery, 68%; and left posterior cerebral artery, 68%. In the patient group, the vasoreactivity of the stenotic middle cerebral arteries was significantly smaller than that of the nonstenotic arteries (P < .05). In addition, the nonstenotic middle cerebral arteries showed significantly less vasoreactivity than the right arteries of the healthy volunteers (P < .01).

Three-dimensional time-of-flight magnetic resonance angiography can be used to quantitatively evaluate acetazolamide-induced vasoreactivity in individual major cerebral arterial territories.
Reduced mortality and brain damage after locomotor activity in gerbil forebrain ischemia.
Authors: Stummer W , Weber K , Tranmer B , Baethmann A , Kempski O
Published: June 2011

Preischemic spontaneous locomotor activity was distinguished in this laboratory as a factor influencing outcome after 15 and 20 minutes of forebrain ischemia in gerbils. Histological investigations were carried out to analyze potential relations between postischemic survival and a reduction of cerebral damage by spontaneous locomotor activity.

Male Mongolian gerbils were divided into two groups, one with access to running wheels ("runners") and one kept in conventional cages ("nonrunners") for 2 weeks preceding forebrain ischemia of 15 or 20 minutes. A total of 99 gerbils were divided in subgroups and were allowed to recover for 2 weeks for assessment of survival. Other subgroups (n = 7 to 9) were killed at day 4 for quantitative histology of selectively vulnerable areas such as hippocampus, cortex, striatum, and thalamus.

Two weeks after 15-minute ischemia, 44% of non-runners had survived compared with 90% of runners (P < .01). With 20-minute ischemia all runners survived compared with 21% of nonrunners. Quantitative histology (15-minute ischemia) revealed selective nerve cell injury in various cerebral regions in both groups. In runners, however, with the exception of the CA1 sector, damage was attenuated in cortex, striatum, and hippocampus. Furthermore, the extent of thalamic infarction was reduced (P < .05).

Locomotor activity before global cerebral ischemia is highly efficient in protecting the brain as demonstrated by enhanced survival and a reduction of tissue damage in Mongolian gerbils. The mechanisms underlying this protection are currently unclear. However, further understanding of this intriguing phenomenon should enhance the understanding of ischemia pathophysiology and lead to the development of new treatment strategies.