bluuebunny/crossref_metadata_2025 huggingface dataset:
Stroke incidence and risk factors for stroke in Copenhagen, Denmark.
Authors: Boysen G , Nyboe J , Appleyard M , Sørensen P S , Boas J , Somnier F , Jensen G , Schnohr P
Published: June 2011

Stroke incidence in Copenhagen, Denmark was recorded in a random population sample of 19,327 persons invited for two health examinations with 5 years' interval from 1976 to 1983. Stroke incidence increased exponentially with age. After adjustment to the age and sex distribution of the Danish population in 1980, the estimated incidence of first stroke was 1.41/1000 women and 2.48/1000 men; the total incidence was 1.94/1000 population. Risk factor analysis was based on the initial examination of 13,088 persons greater than 35 years old without previous stroke who responded to the first invitation, in whom 295 first strokes were subsequently observed. We used the regression model of Cox. However, our use of this model differs from the somewhat automatic procedures normally used to develop prognostic models. Evaluation of the causative effect of a particular risk factor requires that the direction of mutual influences between the factor in question and other risk factors is established/postulated. Among the 16 potential risk factors for stroke we examined, significant effects were found for age, sex, household income, smoking habits, systolic blood pressure, diabetes, plasma cholesterol concentration, ischemic heart disease, and atrial fibrillation. No significant effect could be demonstrated for a positive family history of stroke, years of school education, marital status, alcohol consumption, daily use of tranquilizers, body mass index, or postmenopausal hormone treatment.
Response of the cerebral circulation to profound hypocarbia in neonatal lambs.
Authors: Rosenberg A A
Published: June 2011

Hyperventilation to extremely low arterial carbon dioxide tension (PaCO2) has been used in the management of persistent pulmonary hypertension in newborn infants. With progressive hypocarbia, cerebral vasoconstriction occurs, raising the concern that extreme hypocarbia may result in cerebral oxygen deprivation. Therefore, I evaluated regulation of the cerebral circulation during acute hypocarbia in 10 newborn lambs. Whole-brain and regional blood flows measured using radioactive microspheres, arterial and venous (sagittal sinus) blood gases, and oxygen contents were measured in each lamb at four arterial carbon dioxide tensions. Whole-brain oxygen delivery, oxygen consumption, and fractional oxygen extraction were calculated. Finally, arterial and venous lactate concentrations were measured to assess cerebral lactate production. Whole-brain blood flow (CBF) decreased in a nonlinear fashion as PaCO2 ranged from 46 to 12 mm Hg [In(CBF) = 0.025(PaCO2) + 3.38; r = 0.70, p less than 0.001]. Similar responses were demonstrated for all regional blood flows examined. Cerebral fractional oxygen extraction (E) increased in a nonlinear fashion [In(1-E) = 0.023(PaCO2)-1.37; r = 0.80, p less than 0.001], and cerebral metabolic rate for oxygen was unchanged with hypocarbia. Cerebral venous lactate concentration increased significantly (3.49 +/- 0.23 vs. 2.01 +/- 0.22 mM, p less than 0.001) during severe hypocarbia (PaCO2 of less than 22 mm Hg), and the arterial-venous lactate concentration difference became negative. These results demonstrate uniform responses of whole-brain and regional blood flows and stable cerebral oxygen consumption during moderate and severe hypocarbia. Although there is evidence for cerebral lactate production during severe hypocarbia, this is not likely to indicate cerebral hypoxia as oxygen consumption does not change.
Indomethacin ameliorates ischemic neuronal damage in the gerbil hippocampal CA1 sector.
Authors: Sasaki T , Nakagomi T , Kirino T , Tamura A , Noguchi M , Saito I , Takakura K
Published: June 2011

The purpose of our experiment was to examine whether the cyclooxygenase inhibitor indomethacin ameliorates neuronal injury in the gerbil hippocampal CA1 sector following 5 minutes of forebrain ischemia. Thirty minutes before bilateral carotid artery occlusion, Mongolian gerbils were injected intraperitoneally with 1 (n = 10), 2 (n = 10), 5 (n = 12), or 10 (n = 7) mg/kg of indomethacin. Seven days after occlusion, the gerbils were perfusion-fixed and neuronal density in the hippocampal CA1 sector was assessed. The mean +/- SEM neuronal density in nine unoperated normal gerbils was 307 +/- 9/mm, in 10 untreated ischemic gerbils 55 +/- 21/mm, and in seven vehicle-treated ischemic gerbils 15 +/- 9/mm. The mean +/- SEM neuronal density in ischemic gerbils treated with 1, 2, 5, or 10 mg/kg indomethacin was 132 +/- 28/mm, 154 +/- 29/mm, 176 +/- 30/mm, and 136 +/- 39/mm, respectively. Indomethacin at any dose significantly ameliorated ischemic neuronal damage in the gerbil hippocampal CA1 sector.
Regional cerebral blood flow during an attack of vertebrobasilar insufficiency.
Authors: Sakai F , Ishii K , Igarashi H , Suzuki S , Kitai N , Kanda T , Tazaki Y
Published: June 2011

Using technetium-99m-labeled hexamethylpropyleneamineoxime [( 99mTc]HM-PAO) and single-photon emission computed tomography, we measured changes in regional cerebral blood flow in a 58-year-old man during an attack of vertebrobasilar insufficiency. Angiography demonstrated compression of the left vertebral artery by the osteophytes of cervical spondylosis when the patient turned his head to the left. Measured in the orthostatic position while turning his head to the left during a typical attack of vertebrobasilar insufficiency, regional cerebral blood flow was significantly reduced in the left cerebellum and the right occipital region. Our study illustrates the capability of [99mTc]HM-PAO single-photon emission computed tomography to measure transient reductions in regional cerebral blood flow and to relate these changes to the pathophysiology of vertebrobasilar insufficiency.
Recovery of motor function after stroke.
Authors: Bonita R , Beaglehole R
Published: June 2011

The natural history of recovery of motor function after stroke is described using data from a 1-year community-based study in Auckland, New Zealand. Of 680 patients, 88% presented with a hemiparesis; the proportion of survivors with a persisting deficit declined to 71% at 1 month and 62% at 6 months after the onset of the stroke. At onset, there were equal proportions of people with mild, moderate, and severe motor deficits, but the majority (76%) of those who survived 6 months had either no or only a mild deficit. Recovery of motor function was associated with the stroke severity but not with age or sex; patients with a mild motor deficit at onset were 10 times more likely to recover their motor function than those with a severe stroke. Our results confirm the reasonably optimistic outcome for survivors of stroke and further suggest that recovery of motor function is confined to patients whose motor deficit at onset is either mild or moderate.
Immunohistochemical investigation of ischemic and postischemic damage after bilateral carotid occlusion in gerbils.
Authors: Hatakeyama T , Matsumoto M , Brengman J M , Yanagihara T
Published: June 2011

We investigated progression and recovery of neuronal damage during and after global cerebral ischemia in gerbils after bilateral occlusion of the common carotid arteries, using the immunohistochemical method (reaction for tubulin and creatine kinase BB-isoenzyme). The earliest, but reversible, ischemic lesions occurred after 3 minutes' ischemia in the subiculum-CA1 and CA2 regions of the hippocampus. The lesions became irreversible after 4 minutes' ischemia. The ischemic and postischemic lesions in the cerebral cortex, thalamus, and caudoputamen were partially or completely reversible if the ischemic period was 5 minutes, whereas delayed degeneration occurred in the pyramidal cells of the medial CA1 region after reperfusion for 48 hours (delayed neuronal death). After 10 minutes' ischemia and subsequent reperfusion, delayed neuronal death extended from the medial to the lateral CA1 region; the ischemic and postischemic lesions in the cerebral cortex, thalamus, and caudoputamen also expanded during reperfusion. Our investigation demonstrates that selective vulnerability existed in global cerebral ischemia as in incomplete or regional ischemia and suggests that neurons in many areas of the brain possessed the potential for recovery, progressive deterioration, and even delayed neuronal death depending on the severity and duration of cerebral ischemia.
Declining mortality from stroke in Allegheny County, Pennsylvania. Trends in case fatality and severity of disease, 1971-1980.
Authors: Ahmed O I , Orchard T J , Sharma R , Mitchell H , Talbot E
Published: June 2011

Mortality rates for stroke in 1971, 1974, 1977, and 1980 were obtained for residents of Allegheny County in western Pennsylvania. Hospital case fatality ratios were also obtained in the same 4 years for those discharged with the diagnosis of stroke (ICD 430-438 of the Eighth and Ninth Revisions of the International Classification of Disease) in two large hospitals (greater than 400 beds). Age-adjusted mortality rates per 100,000 population have declined significantly in this period for the whole county as well as for the four sex-race groups. Case fatality ratio in the two hospitals of the study has decreased from 19.6 to 11%. A change in the severity of the disease manifested by a reduction in the number of comatose patients has occurred, and this reduction in comatose patients was responsible for greater than 80% of the decline in case fatality ratio. Coma appears to be the best predictor of mortality among hospitalized stroke cases (r = 0.6, p less than 0.00001). The recent introduction of computed tomography for the diagnosis of stroke in the late 1970s was accompanied by a twofold increase in the survivorship of stroke patients. However, this increase in survivorship may reflect selection bias and is based on ecological association. Further studies are needed to examine the role of computed tomography in improving survival.
Changing prognosis of primary intracerebral hemorrhage: results of a clinical and computed tomographic follow-up study of 104 patients.
Authors: Fieschi C , Carolei A , Fiorelli M , Argentino C , Bozzao L , Fazio C , Salvetti M , Bastianello S
Published: June 2011

One hundred four consecutive cases of primary intracerebral hemorrhage hospitalized at the time of stroke were followed until death or for 1 year. All were treated nonsurgically. The 30-day mortality rate was 30%. Good clinical outcome and complete resolution of the lesion on computed tomography were observed in 49 and 13% of patients, respectively. Age, state of consciousness, and size of the hemorrhage on computed tomography scan were reliable prognostic indicators. The long-term survival rate, 66%, was higher than that previously reported and should be considered in future trials evaluating medical and surgical treatment of intracerebral hemorrhage.
Ischemic infarction in 25 children with tuberculous meningitis.
Authors: Leiguarda R , Berthier M , Starkstein S , Nogués M , Lylyk P
Published: June 2011

Twenty-five cases (38%) of ischemic infarction occurred among 65 cases of tuberculous meningitis in patients less than 14 years of age. The male:female ratio was 1.3:1. The most frequent clinical findings were meningeal signs, fever, alteration of consciousness, cranial nerve involvement, seizures, and focal neurologic deficit. Twenty-three patients had anterior circulation infarcts, and two more had infarcts in the vertebrobasilar territories. Distribution of infarcts in the anterior circulation was shown by computed tomography in the territories of the following arteries: lenticulostriate, 10 cases unilateral and 6 bilateral; middle cerebral, 3 cases; internal carotid, 1 case; multiple areas, 3 cases. Of the 25 ischemic infarction cases, 23 (92%) had hydrocephalus, 19 (76%) basal exudates, and 2 (8%) tuberculomas. Outcome was poor since no patient with infarction recovered completely. Six died and bilateral subcortical infarcts led to a considerably higher mortality than unilateral ones, whether cortical or subcortical.
Bilateral hypoglossal nerve injury after bilateral carotid endarterectomy.
Authors: Gutrecht J A , Jones H R
Published: June 2011

A case of severe bilateral injury to the hypoglossal nerves after two-stage carotid endarterectomy is described. Injury to the hypoglossal nerve occurs in up to 20% of patients undergoing carotid endarterectomy and may result in mild or unnoticed deficits. These injuries must be carefully searched for in patients who will undergo a similar procedure on the opposite side since a bilateral deficit of the hypoglossal nerve is poorly tolerated, causing potentially serious impairment of speech and risk of aspiration.
Reversible osmotic opening of the blood-brain barrier in mice.
Authors: Fredericks W R , Rapoport S I
Published: June 2011

Unilateral reversible osmotic opening of the blood-brain barrier can be produced in mice. Infusion of 1.8 molal arabinose in water at a rate of 0.64 ml/min for 30 seconds into the internal carotid artery consistently results in ipsilateral brain staining by intravascular Evans blue dye. Osmotic opening is concentration-dependent (threshold, 1.6 molal arabinose) and reversible within 4 hours. No long-term neurologic deficit occurs. These results suggest that reversible osmotic blood-brain barrier opening can be applied to disease models in mice.
Serial changes in focal hyperemia associated with hypertensive putaminal hemorrhage.
Authors: Suzuki R , Ohno K , Matsushima Y , Inaba Y
Published: June 2011

Seventeen separate xenon-enhanced computed tomographic images were performed in seven patients with hypertensive putaminal hemorrhage. Regional cerebral blood flow maps were then computed and assessed. All patients were categorized as being of good recovery potential, with moderate-sized hematomas, and all were treated conservatively. The regional cerebral blood flow assessments were scheduled within 4 days after, 2 weeks after, and less than 25 days after the ictus. The initial decrease in hemispheric blood flow ipsilateral to the side of the hematoma was calculated as the ratio of ipsilateral to contralateral hemispheric blood flow and was correlated with the size of the hematoma; that is, the larger the hematoma, the greater the decrease in the ratio of ipsilateral to contralateral hemispheric blood flow. The decrease persisted for 1 month. The mean of the ratio at 2 weeks after onset was 70%, the lowest during follow-up. All cases examined within 4 days after onset demonstrated perihematomatous focal hyperemia, or "luxury perfusion," which accounted for the delayed decrease. The same tissue that had previously shown hyperemia showed decreased regional cerebral blood flow 2 weeks after onset. Our results demonstrate that the luxury perfusion syndrome caused the secondary brain damage even in the cases that were in relatively good condition. The feasibility of treatment can be assessed by considering these results.
Cerebral vasospasm and eclampsia.
Authors: Trommer B L , Homer D , Mikhael M A
Published: June 2011

We describe a patient who experienced focal cerebral and brainstem ischemia in the setting of postpartum eclampsia. Cerebral angiography showed spasm of large- and medium-caliber arteries. This case provides rare documentation that vasospasm may account for cerebral ischemia in eclamptic women with focal signs. This observation suggests that in such patients cerebral angiography may be informative and useful.
Intra-aneurysmal pressure measurements in experimental saccular aneurysms in dogs.
Authors: Sekhar L N , Sclabassi R J , Sun M , Blue H B , Wasserman J F
Published: June 2011

Intra-aneurysmal pressure was studied in an experimental model of saccular aneurysm in dogs, using a vein pouch grafted onto a common carotid arterial bifurcation. The mean and the pulse pressures were recorded simultaneously from within the aneurysm and within the common carotid artery, before and after 50% proximal carotid artery stenosis. These experiments were performed under systemic normotension, hypotension, and hypertension. Normal data suggest that mean intracarotid and intra-aneurysmal pressures are similar and relate in a nearly linear fashion to mean arterial pressure. However, after 50% stenosis, the data had a cubic relationship, the reduction of pressure occurring only in the middle range of mean arterial pressure. Both intra-aneurysmal and intracarotid pulse pressures displayed less dependence on mean arterial pressure. However, sigmoid curves also were observed with the pulse pressures after 50% proximal common carotid artery stenosis. In all cases, after 50% stenosis, the rate of increase of the pulse pressures with mean arterial pressure was greater for higher mean arterial pressures. Our preliminary data indicate that a detailed study of intra-aneurysmal pressure and blood flow in relation to systemic variables such as mean arterial pressure, cardiac output, and peripheral resistance may not only suggest improved means of managing patients with intracranial aneurysms, but also may raise the possibility that, under certain conditions, higher intra-aneurysmal pressures may be induced by downstream stenosis.
Brain eicosanoid levels in spontaneously hypertensive rats after ischemia with reperfusion: leukotriene C4 as a possible cause of cerebral edema.
Authors: Minamisawa H , Terashi A , Katayama Y , Kanda Y , Shimizu J , Shiratori T , Inamura K , Kaseki H , Yoshino Y
Published: June 2011

The relation of brain eicosanoids to progression of cerebral edema was studied in stroke-resistant spontaneously hypertensive rats subjected to incomplete global brain ischemia induced by bilateral occlusion of the common carotid arteries. Thromboxane B2 and 6-keto prostaglandin F1 alpha levels were significantly elevated 5 minutes after reperfusion but returned to control levels by 30 minutes. In contrast, leukotriene C4 levels increased 2 hours after bilateral common carotid artery occlusion and peaked 30 minutes after reperfusion, with higher levels persisting until 60 minutes after reperfusion. Cerebral ischemia was accompanied by cerebral edema early after reperfusion. The edema correlated with increased leukotriene C4 levels. That the increased brain water content was causally related to an increase in leukotriene C4 was supported by results obtained following administration of the 5-lipoxygenase inhibitors ONO-LP-016 and AA-861. Both inhibitors suppressed the increased leukotriene C4 and brain water contents after reperfusion. Our results indicate that leukotriene C4 is closely associated with an induction of ischemic cerebral edema.
Glial swelling during extracellular acidosis in vitro.
Authors: Kempski O , Staub F , Jansen M , Schödel F , Baethmann A
Published: June 2011

Intracellular and extracellular acidosis may determine the ultimate outcome for brain tissue in cerebral ischemia. An extracellular acidosis that occurs in the penumbra zone was investigated in vitro as to its role in the formation of cytotoxic cell swelling. For that purpose, C6 glioma cells or primary cultured astrocytes were suspended in normal isotonic medium in normoxia during acidification to a final pH of 6.2. The cell volume response was determined by flow cytometry using hydrodynamic focusing, which allows one to recognize changes in cell size of less than 1%. A threshold pH of 6.8 was found that had to be crossed to induce cell swelling by acidosis. Once pH fell below this threshold, the increase in cell size appeared to be an all-or-nothing phenomenon. The cells rapidly assumed a final cell size of 115% of normal in the case of C6 glioma or of 118% in the case of primary cultured astrocytes independent of the actual level of acidosis or the duration of exposure. Acidosis-induced glial swelling could be significantly attenuated by 1) addition of amiloride, 2) administration of acetazolamide, or 3) replacement of bicarbonate buffer against N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES). Replacement of extracellular Na+ by choline chloride led to complete prevention of the acidosis-induced cell swelling. Taken together, the findings strongly indicate a central involvement of Na+/H+ and Cl-/HCO3- exchange mechanisms in the development of cell swelling under these conditions. Activation of the Na+/H+ antiporter can be considered an attempt to maintain a normal intracellular pH at the expense of an abnormal cell volume.(ABSTRACT TRUNCATED AT 250 WORDS)
Ultrasonographic follow-up of subclavian stenosis and occlusion: natural history and surgical treatment.
Authors: Ackermann H , Diener H C , Seboldt H , Huth C
Published: June 2011

Continuous-wave Doppler ultrasonography and clinical examination were used over a 2-year period to monitor the natural history of subclavian stenoses and occlusions in 67 patients. Thirty-nine presented with subclavian steal and 28 without. We also studied an additional group of 29 patients who had undergone surgery for subclavian steal syndrome and vertebrobasilar transient ischemic attacks. The results, in terms of both ultrasonographic and clinical criteria, demonstrate the benign nature of the subclavian steal syndrome: all neurologic signs and symptoms were of a transient character. Spontaneous remission of vertebrobasilar transient ischemic attacks occurred in approximately 50% of the initially symptomatic patients, and only 15% of the initially asymptomatic patients experienced vertebrobasilar transient ischemic attacks during follow-up. Doppler ultrasonography revealed progression during follow-up in only 17% of the subclavian stenoses, and in 13% a stenosis was no longer detectable. Still-ongoing brainstem transient ischemic attacks were reported in 24% of the operated patients. The most important factor for the lack of improvement was the occlusion of the bypass. Continuation of transient neurologic symptoms could be observed in only 14% of the patients with intact carotid-subclavian bypass. In conclusion, indications for surgical treatment of the subclavian steal syndrome should be restricted to cases in whom vertebrobasilar transient ischemic attacks occur frequently and are either debilitating or greatly frighten the patient.
Comparison of admission serum glucose concentration with neurologic outcome in acute cerebral infarction. A study in patients given naloxone.
Authors: Adams H P , Olinger C P , Marler J R , Biller J , Brott T G , Barsan W G , Banwart K
Published: June 2011

We studied the ability of serum glucose concentration and neurologic deficits at admission in predicting the outcome of acute cerebral ischemia in 65 patients given naloxone. Among our patients, the volume of infarction on computed tomograms and outcome were strongly related to the severity of neurologic deficits found at admission. Neither a history of diabetes nor hyperglycemia when added to the results of the initial neurologic assessment improved prediction of outcome after acute cerebral infarction.
Involvement of internal elastic lamina in development of induced cerebral aneurysms in rats.
Authors: Kim C , Kikuchi H , Hashimoto N , Kojima M , Kang Y , Hazama F
Published: June 2011

To elucidate the role of the internal elastic lamina in the development of cerebral aneurysm, the bifurcation of the anterior cerebral artery and olfactory artery was histologically studied in control and experimental rats treated with unilateral carotid ligation and renal hypertension. Various stages of aneurysm formation were compared, and it was found that early aneurysmal changes were always present just distal to the apical intimal pad on the anterior cerebral artery side. The internal elastic lamina was thinned and fragmented just distal to the pad even in the very early stage of aneurysm formation when the medial layer was still present. In control rats, the internal elastic lamina had a tendency to thin and fragment at the site where aneurysms would develop in experimental rats. Our study shows that changes of the internal elastic lamina were present just distal to the pad even in control rats, which never develop cerebral aneurysms. Under hemodynamic stress augmented by experimental treatments, further degenerative changes of the internal elastic lamina and involvement of the medial layer are considered to occur and result in aneurysm formation there.
Cerebellar infarction from fibromuscular dysplasia and dissecting aneurysm of the vertebral artery. Report of a child.
Authors: Perez-Higueras A , Alvarez-Ruiz F , Martinez-Bermejo A , Frutos R , Villar O , Diez-Tejedor E
Published: June 2011

Infarction in the vertebrobasilar system presenting as a posterior fossa mass lesion is extremely rare in children. We recently studied and treated a 9-year-old boy with cerebellar infarct produced by angiographically confirmed Type I fibromuscular dysplasia of the vertebral artery, complicated by a dissecting aneurysm. This case appears to be the first reported in the literature.
The Stroke Data Bank: design, methods, and baseline characteristics.
Authors: Foulkes M A , Wolf P A , Price T R , Mohr J P , Hier D B
Published: June 2011

The National Institute of Neurological and Communicative Disorders and Stroke initiated the Stroke Data Bank, which is a multicenter project to prospectively collect data on the clinical course and sequelae of stroke. Additional objectives were to provide information that would enable a standard diagnostic clinical evaluation, to identify prognostic factors, and to provide planning data for future studies. A brief description of the structure and methods precede the baseline characterization of 1,805 patients enrolled in the Stroke Data Bank between July 1983 and June 1986. Two thirds of these patients were admitted within 24 hours after stroke onset. Medical history, neurologic history, and hospitalization summaries are presented separately for the following stroke subtypes: infarction, unknown cause; embolism from cardiac source; infarction due to atherosclerosis; lacune; parenchymatous or intracerebral hemorrhage; subarachnoid hemorrhage; and other. The utility and limitations of these data are discussed.
Effect of internal carotid artery occlusion on intracranial hemodynamics. Transcranial Doppler evaluation and clinical correlation.
Authors: Schneider P A , Rossman M E , Bernstein E F , Torem S , Ringelstein E B , Otis S M
Published: June 2011

Neurologic deficits that occur simultaneously with or subsequent to internal carotid artery occlusion may be influenced by the adequacy of the intracerebral collateral circulation. Transcranial Doppler ultrasonography was used to evaluate mean middle cerebral artery blood velocity and blood flow in major collateral arteries in 78 patients, including 39 patients with 40 internal carotid artery occlusions and 39 control patients with less severe extracranial cerebrovascular disease, matched for age and sex distribution. Middle cerebral artery blood velocity was 38.9 +/- 17.9 cm/sec ipsilateral to an occlusion, 50.9 +/- 18.3 cm/sec contralateral to an occlusion (p less than 0.01), and 56.8 +/- 14.4 cm/sec in the controls (p less than 0.01). Pulsatility index ipsilateral to an occlusion (0.86 +/- 0.32) was reduced compared with contralateral and control pulsatility indexes (1.05 +/- 0.33 and 1.03 +/- 0.18) respectively; p less than 0.05). Major intracerebral collateral arteries were detectable in 94.9% of occlusion patients and in 53.8% of controls (p less than 0.01). A posterior communicating artery was demonstrated ipsilateral to an occlusion in 80.0% of the patients and contralateral to an occlusion in 39.5% (p less than 0.01). An ipsilateral posterior communicating artery was identified in all 10 asymptomatic occlusions and in 75.8% of the symptomatic ones. Pulsatility index was 1.02 +/- 0.34 for asymptomatic occlusions and 0.76 +/- 0.30 for symptomatic occlusions (p less than 0.01). Transcranial Doppler ultrasonography permits noninvasive quantification of the cerebral hemodynamic consequences of internal carotid artery occlusion and direct evaluation of the collateral blood supply, which can be correlated with symptomatology.
Subarachnoid hemorrhage fails to produce vasculopathy or chronic blood flow changes in rats.
Authors: Swift D M , Solomon R A
Published: June 2011

Cerebral blood flow was measured by a [14C]butanol indicator fractionation technique in rats subjected to subarachnoid hemorrhage, in control rats, and in rats given injections of buffered saline into the subarachnoid space (sham hemorrhage). Cerebral blood flow was significantly decreased in both the subarachnoid hemorrhage and sham hemorrhage rats 3 hours after injection. However, blood flow returned to control levels by 24 hours, and measurement for 14 days after subarachnoid hemorrhage failed to show any delayed decrease in cerebral blood flow. Electron microscopic studies of basilar arteries from rats subjected to subarachnoid hemorrhage 72 hours before killing failed to show any of the morphologic changes that have been associated with vasospasm in humans or in higher animal models. Our studies indicate that the rat model of subarachnoid hemorrhage has limited applicability to the study of subarachnoid hemorrhage following ruptured cerebral aneurysms in humans. However, although rats are not a perfect model of this clinical condition, some pathophysiologic changes similar to those observed in human subarachnoid hemorrhage have been demonstrated in this model and deserve further investigation.
Prevention of delayed neuronal death in gerbil hippocampus by ion channel blockers.
Authors: Izumiyama K , Kogure K
Published: June 2011

We used a gerbil model of cerebral ischemia to study the effects of ion channel blockers on neuronal death resulting from enhanced glutamate release and calcium ion influx. The common carotid arteries of gerbils were occluded for 5 minutes and injected intraperitoneally immediately after ischemia with an alkylene iminopropylene derivative (glutamate blocker) or a piperazinyl ethanol derivative (calcium blocker) given at high or low doses. Two vehicle groups received saline or 0.2% methyl cellulose solution. Seven days later, the gerbils were perfusion-fixed and their brains were processed for histologic study. The number of neurons per millimeter (neuronal density) of the CA1 region was calculated, and the neuronal density in each group was statistically compared using the Mann-Whitney U test. Compared with a control group not subjected to carotid ligation, neurons of the two vehicle groups and the low-dose calcium blocker group were almost nonexistent in the CA1 region. Neuronal densities of the glutamate blocker group and the high-dose calcium blocker group were similar and were found to be within normal limits by statistical analysis. Our study shows that detrimental membrane phenomena and the incidence of delayed neuronal death may be counteracted by the systemic administration of these ion channel blockers after ischemic insult.
21-Aminosteroid reduces ion shifts and edema in the rat middle cerebral artery occlusion model of regional ischemia.
Authors: Young W , Wojak J C , DeCrescito V
Published: June 2011

U74006F is a member of a new family of steroid drugs called 21-aminosteroids, which are potent inhibitors of lipid peroxidation with little or no glucocorticoid or mineralocorticoid activity. We investigated the effects of U74006F on the early ionic edema produced by middle cerebral artery occlusion in rats. Intravenous doses of 3 mg/kg U74006F were given 10 minutes and 3 hours after occlusion. Tissue concentrations of Na+, K+, and water at and around the infarct site were measured by atomic absorption spectroscopy and by wet-dry weight measurements 24 hours after occlusion. Compared with vehicle treatment, U74006F treatment reduced brain water entry, Na+ accumulation, K+ loss, and net ion shift by 25-50% in most brain areas sampled in the frontal and parietal cortex. However, reductions of ionic edema were most prominent and reached significance (p less than 0.005, unpaired two-tailed t test) mostly in the frontoparietal and parietal cortex areas adjacent to the infarct site. Our findings suggest that a steroid drug without glucocorticoid or mineralocorticoid activity can reduce edema in cerebral ischemia but that the effects are largely limited to tissues in which collateral blood flow may be present.
Nicardipine reduces calcium accumulation and electrolyte derangements in regional cerebral ischemia in rats.
Authors: Hadani M , Young W , Flamm E S
Published: June 2011

We studied the effects of the calcium channel blocker nicardipine on regional tissue Ca2+, Na+, K+, and water shifts in the brains of seven Sprague-Dawley rats after permanent occlusions of the middle cerebral artery. We also assessed the entry of [14C]nicardipine into the brains of five rats; the highest concentrations of [14C]nicardipine were in the infarcted area. Nicardipine treatment significantly reduced Ca2+ accumulation in the middle cerebral artery territory by 60% compared with six untreated rats 6 hours after arterial occlusion. Eight 125-micrograms/kg boluses of nicardipine given every 30 minutes starting 5 minutes after arterial occlusion also significantly reduced the Na+ and K+ shifts in the middle cerebral artery territory by 40% and 50%, respectively, 6 hours after arterial occlusion. Nicardipine appears to reduce Ca2+ accumulation more than it reduces Na+ and water accumulation and K+ loss. Our results suggest that a calcium channel blocker can protect brain tissues in a model of focal cerebral infarction by directly reducing Ca2+ entry into ischemic cells.
Neurocysticercosis and pure motor hemiparesis.
Authors: Barinagarrementeria F , Del Brutto O H
Published: June 2011

A 49-year-old man with meningeal cysticercosis presented with a pure motor hemiparesis. Computed tomography and magnetic resonance imaging showed a capsular infarction and a suprasellar cyst with surrounding arachnoiditis. Cerebrospinal fluid analysis confirmed the diagnosis as it showed positive immunologic reactions to cysticerci. This is the first reported case of pure motor hemiparesis due to a parasitic disease of the central nervous system.
The Detection of Carotid Artery Obstruction: A Correlation With Arteriography
Authors: WISE GARY , BROCKENBROUGH E. C. , MARTY RAYMOND , GRIEP ROBERT
Published: June 2011

Intravenous radioisotope arteriography, carotid compression ocular plethysmography, and supraorbital Doppler studies were more accurate than ophthalmodynamometry in the detection of the presence or absence of carotid artery obstruction in 35 patients. Abnormal results were present in patients with carotid obstruction who did not have a carotid bruit.

The isotope method provides information about relative blood flow through the two carotid arteries. Ocular plethysmography and supraorbital Doppler studies provide information about collateral circulatory pathways in patients with carotid obstruction.

Currently, they are most useful clinically in patients who are erroneously thought to have only intracranial vascular disease since abnormal results suggest an extracranial carotid lesion. These methods will not reveal abnormalities in patients with small, ulcerated carotid plaques which are a source of embolic material but which are not decreasing carotid blood pressure and flow.
Effect of Pa

CO

CO
2

on Hyperemia and Ischemia in Experimental Cerebral Infarction
Authors: YAMAGUCHI TAKENORI , REGLI FRANCO , WALTZ ARTHUR G.
Published: June 2011

To assess the effects of Pa

CO

CO
2

on cerebral ischemia and reactive hyperemia, the right middle cerebral artery was occluded in 18 cats. Four to six hours later, Pa

CO

2
was adjusted by mechanical ventilation, with or without CO
2
, to less than 20 torr in four cats, 31 to 38 torr in six, and 46 to 68 torr in eight. Regional cerebral blood flow (CBF) then was measured at multiple sites in each hemisphere by autoradiography. In regions of brain tissue outside the distribution of the occluded middle cerebral artery, log
10
CBF correlated positively with Pa

CO

CO
2

. In ischemic regions, CBF was higher in normocapnic cats. Reactive hyperemia occurred in two cats of the hypocapnic group, in four cats of the normocapnic group, but in only one hypercapnic cat (Pa

CO

CO
2

= 46 torr). Hyperemia also was found outside potentially ischemic regions in five cats. Multiple hyperemic foci developed in six cats. Neither hypocapnia nor hypercapnia was associated with a smaller size or higher CBF of regions of cerebral ischemia produced by occlusion of a middle cerebral artery, although hypercapnia inhibited the development of hyperemia.
Demonstration of Alpha and Beta Adrenergic Receptors in Canine Cerebral Vasculature
Authors: LOWE ROBERT F. , GILBOE DAVID D.
Published: June 2011

The cerebral vascular effects of various adrenomimetic agents were examined in 12 isolated canine brains perfused with blood at constant flow. Changes in cerebral vascular resistance (CVR) and the magnitude of pressor or depressor responses observed following drug injection were examined.

The presence of alpha adrenergic receptors in this vascular bed is indicated by the increased CVR observed when phenylephrine, norepinephrine, and epinephrine were administered and by the reduced or reversed pressor actions of these compounds following treatment with the alpha adrenergic blocking drug phenoxybenzamine HCl.

The presence of beta adrenergic receptors in this vascular bed is indicated by the decreased CVR noted when isoproterenol was given and by the reduced depressor actions of this compound following treatment with the beta adrenergic blocking drug propranolol. Further evidence for the presence of beta adrenergic receptors is demonstrated by the vasomotor reversal to epinephrine which was observed following alpha suppression with phenoxybenzamine.

As catecholamine blood levels in intact dogs are low in comparison to those achieved in these studies, it appears doubtful that circulating catecholamines play an important physiological role in the regulation of CVR. Possible explanations are considered for the lower response of the cerebral vasculature to catecholamines when this response is compared to that observed in other vascular beds.
The Relation Between Cerebral Oxygen Consumption and Cerebral Vascular Reactivity to Carbon Dioxide
Authors: FUJISHIMA MASATOSHI , SCHEINBERG PERITZ , BUSTO RAUL , REINMUTH OSCAR M.
Published: June 2011

The mechanisms whereby CO
2
affects cerebral vessels are not as simple as once thought,
1, 2
and are probably both directly on cerebral vascular walls
3, 4
and indirectly by action on brain stem neurones.
5
Furthermore, cerebral vascular reactivity to CO
2
has been reported to be altered by a number of physiological and pathological circumstances. The capacity to dilate to increased Pa

CO
CO2

is decreased in cerebral vascular lesions,
6-8
and is affected by changes in cerebral perfusion pressure.
9
Cervical sympathectomy is said to increase CBF response to Pa

CO
CO2

changes, whereas sympathetic nerve stimulation abolishes reactivity to CO
2
.
10
Deep anesthesia, hypothermia, or trauma to brain reduces reactivity to cerebral vessels to CO
2
, the one common denominator for these states being reduced cerebral metabolism. This report demonstrates that the capacity of cerebral vessels to dilate or constrict in response to changes in Pa

CO
CO2

is influenced by cerebral oxygen consumption.
Current Status of the Epidemiology of Brain Infarction Associated with Occlusive Arterial Disease
Authors: KANNEL WILLIAM B.
Published: June 2011

Although large gaps in our knowledge concerning the epidemiology of cerebrovascular disease are apparent, careful inspection of all existing data now makes it possible to see certain patterns emerging which suggest certain risk factors for stroke.

While the problem of differential diagnosis of the various categories of cerebrovascular disease presents a major obstacle to obtaining an undistorted picture of the epidemiological features of stroke from death certificate mortality data, the addition of evidence from prospective studies, including those in Framingham, Massachusetts, reveals that various types of arterial occlusion with cerebral infarction are by far the most prevalent type of stroke. Any specific origin of atherosclerosis remains obscure, as possible etiological candidates including dietary alterations in salt, fat and refined carbohydrate, sedentary living, excessive calories promoting obesity, the cigarette habit and even the mineral content of water in addition to marital status have all been incriminated. However uncertain the final answer is, certain precursors for atherosclerosis, such as hypertension, diabetes, and hyperlipidemia, are important. Of these, hypertension is clearly the most important contributor to stroke incidence. Certain combinations of items carry more risk than do the same items singly. For example, the risk of a brain infarction in diabetics with hypertension is probably about six times that of normal subjects. In persons under 50 at the time of measurement risk of cerebral infarction is possibly ten times higher in those with hypertension and elevated lipids than in those without either elevated. This compounding of risk has pathogenetic, preventive and public health implications. For purposes of stroke screening alone the most efficient and practical method would be to determine casual blood pressure, although it must be stated that as yet there is uncertainty concerning the change in the risk if such blood pressure is treated.
The Role of Socioeconomic Factors in Cerebral Atherosclerosis
Authors: LOEWENSON RUTH B. , FLORA GEORGE C. , BAKER A. B.
Published: June 2011

This report presents an analysis of autopsy material from 3,942 cases of age 20 and older in whom the circle of Willis was scored for the severity and the extent of atherosclerosis. Several criteria were used to assess the effect of socioeconomic factors on cerebral atherosclerosis; these consisted of the financial hospital status of the patient, the place of residence, and occupation and physical activity. In the female patients it appeared that the indigent cases had a slightly higher prevalence of cerebral atherosclerosis than the private cases. In the males a difference in prevalence was found between urban and rural cases, the urban males showing higher scores. A comparison between a group of patients with mostly sedentary occupations and a group with more physically active occupations revealed no difference in atherosclerosis scores.
Regional Cerebral Blood Flow in Man Determined by the Initial Slope of the Clearance of Intra-arterially Injected l33Xe
Authors: OLESEN JES , PAULSON OLAF B. , LASSEN NIELS A.
Published: June 2011

The regional cerebral blood flow can be calculated from the initial slope of the logarithmically displayed clearance curve following intra-arterial injection of
133
Xe (rCBF
initial
). The relationship between this parameter and the values resulting from stochastic (height over area) and compartmental analyses is extensively discussed. Experimental results demonstrate the theoretically expected close relationship between rCBF
initial
and flow of gray substance (rCBF
initial
20% to 30% lower than F
g
). It is shown how the cerebral clearance curve (normally biexponential) with low flow values becomes gradually monoexponential. Thus only flow of gray substance changes, whereas flow of white substance is independent of CBF
∞
. CBF
10
was shown to overestimate CBF
∞
with about 15% independent of the flow level. Correlation between CBF
initial
and CBF
10
was linear (r=0.98) at CBF
10
values above 20 ml/100 gm/min.

The CBF
initial
normal value is found to be 64±9 ml/100 gm/min, and the interchannel coefficient of variation is 8.2%. A correction for remaining radioactivity from previous measurements is described. Using this, no significant difference was found between repeated resting state measurements.

The CBF
initial
-Paco
2
relationship was found to be best described as exponential. In a group of patients with various intracranial diseases, 1 mm Hg change in Paco
2
resulted in 4% change of CBF
initial
quite independent of the CBF
initial
level.
Hemiplegic Syndrome of the Posterior Cerebral Artery
Authors: BENSON D. Frank , TOMLINSON E. B.
Published: June 2011

An unusual syndrome is described consisting of right hemiplegia, right hemisensory loss, mild naming disturbance, and severe alexia coupled with normal expressive language and ability to write. The clinical syndrome of alexia without agraphia strongly suggests involvement of the left posterior cerebral artery. A study of the territory of distribution of the posterior cerebral artery would appear to confirm the possibility that occlusion of this vessel could produce the entire symptom picture. Of particular interest was the unusual hemiplegia, involving both limbs and face equally, but with a minimum of spasticity.
Sex difference in antithrombotic effect of aspirin.
Authors: Spranger M , Aspey B S , Harrison M J
Published: June 2011

A number of clinical trials suggest that the antithrombotic effect of aspirin is limited to men. To test the possibility that this is due to a sex difference in the inhibitory effect of aspirin on platelet behavior, we studied whole-blood platelet aggregation in men and women and in male patients with carcinoma of the prostate receiving hormone therapy. The in vitro inhibitory effect of aspirin on so-called spontaneous platelet aggregation induced by stirring whole blood and monitored by the decrease in the number of singleton platelets was greater in men (mean +/- SD inhibitory ratio 1.54 +/- 0.30 in men, 1.23 +/- 0.22 in women; p less than 0.001). The inhibitory effect of aspirin was reduced in orchiectomized male patients and was restored by the addition of testosterone to blood samples. Estradiol had no detectable influence on the inhibitory effect of aspirin. Testosterone thus seems to influence platelet aggregation and its inhibition by aspirin as assessed by whole-blood in vitro aggregometry. Possible mechanisms for this effect of testosterone and its relevance to the choice of antithrombotic therapy are discussed.
Blood velocity in the middle cerebral artery and regional cerebral blood flow during carotid endarterectomy.
Authors: Halsey J H , McDowell H A , Gelmon S , Morawetz R B
Published: June 2011

Blood flow velocity in the middle cerebral artery, determined by transcranial Doppler ultrasonography, was monitored during 31 carotid endarterectomies. Electroencephalogram (EEG) was also monitored, and regional cerebral blood flow (rCBF) was measured. The relation between rCBF and mean velocity was dependent on the rCBF level; the correlation was strong if rCBF was less than 20 ml/100 g/min but weak if rCBF was greater than that level. Ipsilateral EEG suppression was related to a rCBF threshold of 9 ml/100 g/min and to a mean velocity threshold of 15 cm/sec; the rCBF threshold was more specific for EEG change. Postischemic hyperemia was evident in measurements of mean velocity but not of rCBF. These disparities between mean velocity and rCBF seemed to be due to three factors: 1) disproportionately high mean velocity in patients with stenosis of the middle cerebral artery, 2) a nonlinear relation between mean velocity and rCBF, and 3) the anatomically different regions of the brain in which mean velocity and rCBF are measured. The velocity measurement appeared to be relatively more sensitive than rCBF to hemodynamic events in the corpus striatum and internal capsule.