bluuebunny/crossref_metadata_2025_split huggingface dataset:
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.