bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of intracarotid hyperosmolar mannitol on cerebral cortical arterioles--a morphometric study.
Authors: Beck D W , Hart M N , Hansen K E
Published: June 2011

The morphometric response of cerebral cortical arterioles to intracarotid hyperosmolar mannitol was assessed utilizing a technique of rapid freezing of rat brain tissue in vivo. A significant decrease in the wall to lumen (W/L) ratio was noted in the small parenchymal arterioles (20-49 mu) (p less than .0001) ipsilateral to the mannitol infusion. Larger arterioles showed a decreased W/L ratio but this change was not significant. Control infusion of 0.9% NaCl resulted in no change in arteriolar caliber. These results indicate that intracarotid hyperosmolar mannitol causes a direct vasodilatory response in small cerebral cortical arterioles.
A collaborative study of stroke incidence in Japan: 1975-1979.
Authors: Komachi Y , Tanaka H , Shimamoto T , Handa K , Iida M , Isomura K , Kojima S , Matsuzaki T , Ozawa H , Takahashi H
Published: June 2011

A Japan Collaborative Study of Stroke covering 20 regional and occupational population groups was conducted with the support of the Ministry of Health and Welfare. In this study 17,423 males and 16,856 females, aged 40 to 69, were followed up prospectively from 1975 to 1979. The average annual incidence of all types of stroke was 3.94 for men and 2.52 for women per 1,000 population. The incidence of cerebral hemorrhage for men and women stood at 1.26 and 0.59 and that of cerebral infarction at 1.87 and 1.10 respectively. The difference in incidence between the sexes was large particularly in the age range of 40-49. The incidence of all types of stroke, cerebral hemorrhage and cerebral infarction increased with age. The incidence of all strokes in Japan during the period 1975-1979 appears to have decreased in comparison with that in 1960-1969, but tended to be still higher than that in Western countries.
Flow patterns in the human carotid artery bifurcation.
Authors: Motomiya M , Karino T
Published: June 2011

To elucidate the connection between blood flow and the localized genesis and development of atherosclerosis and thrombosis at the human carotid artery bifurcation, detailed studies of the flow patterns and distributions of fluid velocity and wall shear rate in this region were carried out using a transparent segment of the carotid artery, prepared from a human subject postmortem, and cinemicrographic techniques. It was found that a recirculation zone which consisted of a pair of complex spiral secondary flows, symmetrical about the common median plane of the bifurcation, was formed in the carotid sinus over wide ranges of inflow Reynolds numbers, Re0, and flow rate ratios, Q1/Q0 (internal/common). The formation and the size of the recirculation zone were largely dependent on Q1/Q0, as well as on Re0. The size of the recirculation zone increased from approximately 4 mm at Re0 = 300 to a maximum of approximately 9 mm at Re0 greater than 800. The results suggest that, under physiological conditions (Re0 approximately 600, Q1/Q0 approximately 0.7), a standing recirculation zone exists in the carotid sinus, thereby affecting local mass transfer and interactions of blood cells with the vessel wall, which may lead to the incidence of atherosclerosis and thrombosis in this region.
Cerebral angiographic and clinical differences in carotid system transient ischemic attacks between American Caucasian and Japanese patients.
Authors: Nishimaru K , McHenry L C , Toole J F
Published: June 2011

Cerebral angiographic findings of 32 Japanese patients with carotid system TIA's were compared with those of an equal number of age and sex matched American Caucasians. The end points included irregularity, ulceration, stenosis or occlusion of the carotid artery appropriate to the side of TIA. Atherosclerotic changes were found in 27 patients (84.4%) of the Japanese and 30 patients (93.7%) of the American patients. Mild lesions (49% stenosis and below) were similar in either frequency of topography between both groups; namely 25 intracranial and 17 extracranial lesions in Japanese as well as 29 intracranial and 10 extracranial in Caucasian patients. There was, however, an extra-intracranial difference in severe lesions (50% stenosis and above) between American Caucasian and Japanese patients; 10 of 12 severe lesions in Japanese were located intracranially, while 17 of 20 severe lesions present in the American group occurred in the extracranial portion of the internal or common carotid arteries.
Cervico-cephalic arterial thrombi and thromboemboli in moyamoya disease--possible correlation with progressive intimal thickening in the intracranial major arteries.
Authors: Yamashita M , Oka K , Tanaka K
Published: June 2011

Ninety-two thrombi and/or thromboemboli of cervico-cephalic arteries were confirmed histopathologically in 16 out of 22 patients with moyamoya disease. Included were 74 white thrombi mainly composed of fibrin and platelets, 9 organized thrombi and 9 mixed thrombi containing red blood cells. Thirteen microthrombi and one organized thrombus were located in the cervical arteries. Seventy-eight thrombi were present in the intracranial major arteries. Sixty-five were white microthrombi attached to the luminal surface of the arteries. The intracranial microthrombi were most frequently observed at the distal ends of the internal carotid arteries (29 thrombi). The fibrous thickening of the intima and edema in the innermost luminal surface were the most common vascular alterations associated with the thrombus formation. In two patients, thrombus formation was associated with fissure of the thickened intima and a dissecting aneurysm. We concluded that in patients with moyamoya disease the thrombi may be closely related to the development of intimal thickening in the intracranial arteries, particularly at the distal ends of the internal carotid arteries.
Cerebrovascular complications associated with idiopathic hypertrophic subaortic stenosis.
Authors: Furlan A J , Craciun A R , Raju N R , Hart N
Published: June 2011

One hundred fifty patients with idiopathic hypertrophic subaortic stenosis (IHSS) were followed-up for an average of 5.5 years. There were 95 males and 55 females with a mean age of 51 years. Patients usually presented with cardiac symptoms or syncope; no patient presented with stroke. Eight patients (5%) died during follow-up, all from cardiac causes. Eleven patients (7%) developed cerebrovascular complications; 5 (3%) had a stroke and 6 (4%) had TIA only. Patients with IHSS and atrial fibrillation have a much greater stroke risk. Mitral annulus calcification may also increase stroke risk in IHSS. However, stroke is almost never the presenting manifestation of IHSS, and the longterm risk of stroke for most patients with known IHSS is low.
Effect of selective inhibitor of thromboxane A2 synthetase on experimental cerebral vasospasm.
Authors: Fukumori T , Tani E , Maeda Y , Sukenaga A
Published: June 2011

Experimental cerebral vasospasm was induced in the canine basilar artery by an intracisternal injection of fresh autogenous arterial blood. Delayed vasospasm was defined as a reduction to less than 75% of the caliber of control basilar artery 5 days after the intracisternal blood injection. A selective inhibitor of thromboxane A2 synthetase, sodium(E)-3-[4-(3-pyridylmethyl) phenyl]-2-methyl-2-propenoate, was infused intravenously for 1 or 2 hrs at 50 micrograms/kg/min in normal animals exhibiting vasospasm. Angiographic evidence of cerebral vasospasm was not reversed. Mean regional cerebral blood flow was not significantly increased in normal and vasospastic animals, but a mean difference of regional cerebral blood flow was significantly increased only in vasospastic animals. Mean arterial blood pressure and pulse rate were not seriously changed in normal and spastic animals. Another selective thromboxane A2 synthetase inhibitor, (E)-3-[4-(1-imidazolylmethyl)phenyl]-2-propenoic acid hydrochloride monohydrate, showed a similar effect on the caliber of the basilar artery, regional cerebral blood flow, blood pressure, and pulse rate, in vasospastic animals. Venous blood was taken from the internal jugular vein, and the mean platelet aggregation induced by 10 micrograms/ml of collagen was inhibited by the infusion of either selective inhibitor at 50 micrograms/kg/min for 2 hrs. However, mean platelet aggregation rates in vasospastic animals before and after treatment with either selective inhibitor were not significantly different to those in normal animals.
Glucagon stimulates ketone utilization by rat brain slices.
Authors: Kirsch J R , D'Alecy L G
Published: June 2011

Glucagon has been shown previously to increase further the enhanced tolerance for hypoxia observed in mice with elevated blood ketones. Glucagon is also known to increase blood glucose and to alter directly the metabolism of some (liver) cells. Both the increase in blood glucose and altered cellular metabolism could contribute to the increase in tolerance for hypoxia observed in mice given glucagon in combination with the ketone, beta-hydroxybutyrate. To evaluate the systemic component of this hypothesis, blood glucose, beta-hydroxybutyrate, and glucagon were elevated alone or simultaneously and hypoxic tolerance of mice was measured. To identify possible cellular effects of glucagon on glucose or ketone metabolism, we measured the incorporation of radiolabeled glucose or beta-hydroxybutyrate into CO2 or total lipid in isolated rat brain slices. Both glucagon and glucose increased hypoxic tolerance of ketotic mice but our data do not support the hypothesis that glucagon's action was only through an elevation of blood glucose. In brain slices glucagon stimulated the incorporation of beta-hydroxybutyrate into CO2 both in the presence or absence of additional glucose. These results demonstrate that glucagon has a direct effect on brain metabolism which may contribute to the increased tolerance for hypoxia. They, however, do not exclude the possibility that glucagon is working in addition to increase hypoxic survival in ketotic mice by increasing the availability of glucose to the brain.
Atrial fibrillation, TIAs and completed strokes.
Authors: Harrison M J , Marshall J
Published: June 2011

A retrospective survey of 1076 patients with completed strokes and 789 with transient ischemic attacks (TIAs) revealed that 5.6% of those with completed strokes but only 1.6% of those with TIAs were in atrial fibrillation. TIAs in the presence of atrial fibrillation tended to last longer than 60 minutes except in individuals who had coexistent carotid disease that might have been the source of their attacks. It is suggested that emboli from the fibrillating atrium rarely cause brief TIAs, and more usually cause 'long' TIAs or completed strokes.
Clinical experience with the use of xenon-enhanced CT blood flow mapping in cerebral vascular disease.
Authors: Yonas H , Wolfson S K , Gur D , Latchaw R E , Good W F , Leanza R , Jackson D L , Jannetta P J , Reinmuth O M
Published: June 2011

Cerebral blood flow mapping with the xenon-enhanced/CT method has become a useful clinical tool in the management of patients with occlusive cerebral vascular disease. Studies involving 4-5 minutes of inhaling a xenon/oxygen mixture (less than or equal to 35%) can now be performed routinely with acceptable patient tolerance and compliance. Four cases with acute and chronic ischemic injuries are reported here to illustrate the manner in which this method has been used to characterize flow pattern in such patients and the relevance of this flow information to clinical patient management.
Treatment of acute focal cerebral ischemia with propranolol.
Authors: Capraro J A , Reedy D P , Latchaw J P , Slugg R M , Stowe N T , Lesser R P , Little J R
Published: June 2011

Propranolol's potential as a protective agent against tissue injury has been noted in experimental myocardial, renal and early acute focal cerebral ischemia. The purpose of the present investigation was to study further the effects of racemic (d,l) propranolol on blood-brain barrier permeability, morphological changes, cortical electrical activity, and regional cerebral blood flow (rCBF) in experimental focal cerebral ischemia. Thirty adult cats, anesthetized with nitrous oxide, underwent 6 hours of right middle cerebral artery (MCA) occlusion. Fifteen cats were untreated. Fifteen cats were given a continuous infusion of racemic propranolol (1 mg/kg/hr) for 7 hours beginning 1 hour before MCA occlusion and a 4 mg/kg bolus immediately before occlusion, both directly into the right carotid artery. Right Sylvian rCBF did not significantly differ in the treated and untreated groups. Carbon filling defects and vital dye (i.e., Evans blue and fluorescein) extravasation were less severe in the propranolol treated animals. Light microscopic findings demonstrated no difference in infarct size between the two groups. The findings suggest that at doses given, racemic propranolol does not exert a protective effect upon cerebral tissue subjected to 6 hours of incomplete ischemia.
Hemolysate-induced contraction in smooth muscle cells of the guinea pig basilar artery.
Authors: Fujiwara S , Kuriyama H
Published: June 2011

The hemolysate (10(-5)-10(-2) times dilution; original hemoglobin concentration was 0.83 +/- 0.10 X 10(-3)M) evoked the contraction in a dose dependent manner, and this contraction was composed of low and high sensitive responses as estimated from the Eadie-Hofstee's plot. Indomethacin (10(-7)-10(-5)M) inhibited the latter component in the hemolysate-induced contraction. The membrane potential of smooth muscle cells was -50 mV and the cell was electrically quiescent. The hemolysate (greater than 10(-2) times dilution) depolarized the membrane and increased the ionic conductance of membrane. In rare occasions, the spike potential was triggered on the hemolysate-induced depolarization. The hemolysate (10(-5)-3 X 10(-3) times dilution) produced the contraction with no change in the membrane property. Carbocyclic thromboxane A2 ( cTXA2 ; 2.8 X 10(-10)M) produced the contraction without depolarization of the membrane, yet the TXA2 synthesis inhibitor, OKY-1581 (10(-5)M), had no effect on the hemolysate-induced contraction. PGE1, PGE2 and PGF2 alpha (2.8 X 10(-6)M) produced the contraction with no change in the membrane property. The contraction evoked by 2.8 X 10(-6)M PGF2 alpha corresponded well with that evoked by 3 X 10(-3) times dilution of the hemolysate. Removal of the endothelium by mechanical rubbing modified the hemolysate-induced contraction. Under the assumption that OKY-1581 is a selective inhibitor for TXA2 synthesis, the major part of the contraction (the indomethacin sensitive component) of the basilar artery is postulated to be due to synthesis of the primary PG rather than TXA2 by the hemolysate, yet the hemolysate itself, has to some extent a direct action in evoking the small contraction.
Cerebral infarction with transient signs (CITS): do TIAs correspond to small deep infarcts in internal carotid artery occlusion?
Authors: Bogousslavsky J , Regli F
Published: June 2011

Among 75 patients in whom internal carotid artery (ICA) occlusion was discovered on angiography, 5 presented with transient ischemic attacks (TIAs) without suffering a stroke. Although neurological examination was normal, all had evidence for one (in one instance two) hypodense lesion suggesting infarction contralateral to the neurological dysfunction on computed tomography (CT). These infarcts were small and deeply located, being indistinguishable from lacunes in most cases. We suggest that cerebral infarction with transient signs ( CITS ) may be a usual finding in patients with ICA occlusion who suffer isolated TIAs. In these cases, CITS may correspond to incomplete cerebral necrosis related to a well-developed collateral supply, or to recurrent ischemia in the region of an old "silent" infarct. CITS should be differentiated from TIAs, which may be diagnosed only in absence of visible structural lesion.
Regional cerebral blood flow and oxygen consumption in human aging.
Authors: Pantano P , Baron J C , Lebrun-Grandié P , Duquesnoy N , Bousser M G , Comar D
Published: June 2011

The oxygen-15 continuous inhalation technique and PET were used to study the age-related changes in regional CBF and CMRO2. Twenty-seven patients, aged 19 to 76 years, free of any history of cerebral disease and vascular risk factors were examined in "resting state." CBF, CMRO2 and oxygen extraction fraction (OEF) values were calculated in seven different brain structures as well as in mean gray matter. Left-right ratios were also computed for all symmetrical structures analyzed. Mean gray CBF, but not mean gray CMRO2, decreased linearly with age (p less than 0.02). However, when younger subjects (less than or equal to 50 yrs) were compared to older subjects (greater than 50 yrs), an age-related matched decrease in CBF and CMRO2 was observed in mean gray matter (18% and 17%, p less than 0.05) and in all gray matter regions analyzed, particularly in frontal, temporo-sylvian and parieto-occipital cortex. White matter CBF and CMRO2 remained remarkably stable with advancing age. Although the possibility of methodological artifacts was considered, we favor progressive loss of cortical neurones and/or diminished activity of those remaining to explain our findings. In addition, age-related changes in cognitive activities might also be involved.
Pure sensory stroke caused by a small cortical infarct in the middle cerebral artery territory.
Authors: Derouesné C , Mas J L , Bolgert F , Castaigne P
Published: June 2011

A patient with the sudden onset of a pure sensory deficit involving cortical modalities in his left hand and foot is described. CT scan suggested the lesion responsible for the deficit was a small cortical infarct in the middle cerebral artery territory, involving the middle part of the post-central gyrus and interrupting thalamo-cortical pathways in the corona radiata.
Peripheral hypoglossal nerve palsy caused by lateral position of the external carotid artery and an abnormally high position of bifurcation of the external and internal carotid arteries--a case report.
Authors: Ueda S , Kohyama Y , Takase K
Published: June 2011

An unusual case of peripheral hypoglossal nerve palsy, caused by lateral position of the external carotid artery and an abnormally high carotid bifurcation is reported. Improvement followed ligation and cutting of the external carotid artery at its origin.
Risk of stroke in patients with mitral annulus calcification.
Authors: Furlan A J , Craciun A R , Salcedo E E , Mellino M
Published: June 2011

63 patients with mitral annulus calcification (MAC) were followed for an average of 3.4 years. Two patients experienced TIA, both ipsilateral to a previous endarterectomy site, and IV-DSA demonstrated normal extracranial vessels. There were 3 strokes (5%), all fatal, but none could be attributed to embolism. Embolic stroke due to MAC is rare and difficult to prove due to coexistent atherosclerosis. Associated cardiac conditions such as atrial fibrillation, which might increase the risk of embolism, usually occur with MAC greater than or equal to 5 mm. In many patients, MAC may be better viewed as a marker of generalized calcific atherosclerosis rather than as an immediate embolic source.
Multifaceted therapy after global brain ischemia in monkeys.
Authors: Gisvold S E , Safar P , Rao G , Moossy J , Kelsey S , Alexander H
Published: June 2011

The pathophysiology of postischemic encephalopathy is complex, and includes tissue acidosis, edema, hypoperfusion, membrane dysfunction, impaired energy production, and possibly hypermetabolism. We tested the hypothesis that this multifactorial clinical problem must be approached with multifaceted therapy, with specific treatment aimed at each of the above postischemic changes. Eighteen minutes of complete global brain ischemia was produced with a higher pressure neck cuff in pigtailed monkeys. Control treatment postischemia (n = 9): 1) Normotension (MAP greater than or equal to 80 mmHg) restored within 2 min postischemia, 2) controlled ventilation for 24 hours with PaCO2 = 25 mmHg, 3) normothermia, and 4) phenytoin seizure prophylaxis from 20 hours postischemia. Experimental treatment (n = 10): Control treatment plus the following modifications: 1) Hemodilution to hematocrit 25% at 1-4 min postischemia, 2) brief hypertension (MAP 130 mmHg for 5 min) after accomplished hemodilution, 3) hypothermia for 6 hours, 4) pentobarbital 30 mg/kg i.v., 5) dexamethasone 4 mg/kg i.v. Outcome was evaluated at 96 hours postischemia by overall performance categories (OPC) (OPC I = normal, OPC V = brain death), neurologic deficit (ND) scores (100% ND = brain death, 0% ND = normal), and histologic damage scores of the brains. Results: Brain death developed in 1/9 control and 0/10 treated animals. The number of awake monkeys (OPC I and II) at 96 hours postischemia was significantly higher in the treated group (7/10) than in the control group (2/9) (p = 0.05). The median ND scores for the two groups were 16 and 35% respectively (p greater than 0.05). The results strongly suggest that postischemic treatment may be beneficial and that a multifaceted therapeutic approach is worth pursuing.
Cortical blood flow during extracranial-intracranial bypass surgery.
Authors: Carter L P , Crowell R M , Sonntag V K , Spetzler R F
Published: June 2011

Cortical blood flow was evaluated at the time of surgery with a thermal diffusion flow probe in 25 extracranial-intracranial bypass operations. The procedures were performed 14 times for carotid occlusion, 6 times for inaccessible carotid stenosis, on 3 occasions for middle cerebral occlusion, once for basilar occlusion and once for middle cerebral stenosis. Fifty-seven different cortical regions were evaluated before and after completion of the anastomosis. During temporary occlusion of the cortical vessel, no significant changes in cortical blood flow were identified. The mean flow pre-bypass was 58 ml/100 g/min and postbypass was 66. This was a significant difference. When initial ischemic areas were evaluated, flows increased from 36 ml/100 g/min to 52 ml/100 g/min. These postbypass flows were statistically different than the flow values in the nonischemic areas of 75 ml/100 g/min. Blood pressure and arterial carbon dioxide tension did not vary significantly. Extracranial-intracranial bypass increases cortical flow in ischemic areas although this does not bring the flow into the normal range.
Evaluating and predicting outcome of acute cerebral vascular accident.
Authors: Dove H G , Schneider K C , Wallace J D
Published: June 2011

An innovative evaluation method is used to study the outcomes and clinical predictions for 97 patients with acute cerebral vascular accidents. The technique involved the participation of several professional disciplines in selecting baseline and treatment variables and making independent predictions about the functional status of patients upon discharge from the stroke treatment center. The data suggest that (1) baseline variables were more important than treatment variables in the participants' predictions about the patients' short-term outcomes; (2) stroke unit staff members were generally successful in predicting patients' functional status; and (3) stroke extensions and other complications are important factors which affect stroke patients' short-term outcomes.
Cerebral blood flow responses to hypocapnia during hypotension.
Authors: Artru A A , Colley P S
Published: June 2011

Cerebral vascular responses to hypocapnia during hypotension to a mean arterial blood pressure (MAP) = 50 mm Hg induced with sodium nitroprusside (SNP, n = 12) or trimethaphan (TMP, n = 12) were examined in dogs. Cerebral vascular resistance (CVR) and cerebral blood flow (CBF) at PaCO2 = 40 mm Hg, and PaCO2 = 20 mm Hg were examined first at normal MAP then at hypotension in six dogs in the SNP group and six dogs in the TMP group. In both the SNP group and the TMP group, CO2 responsiveness, as indicated by increased CVR and decreased CBF, was intact at normal MAP, but absent during hypotension. In the remaining 6 of 12 dogs in the SNP group and 6 of 12 dogs in the TMP group, CO2 responsiveness at MAP = 50 mm Hg was examined without prior determination of CO2 responsiveness at normal MAP. These additional studies were performed to rule out the possibility that absent CO2 responsiveness during hypotension in the initial groups resulted from (1) physiologic deterioration of the preparation with time, or (2) adaptation of brain extracellular fluid pH to a preceding period of hypocapnia. Again, during both SNP- or TMP-induced hypotension CO2 responsiveness was absent.
The profile of recovery from stroke and factors influencing outcome.
Authors: Kotila M , Waltimo O , Niemi M L , Laaksonen R , Lempinen M
Published: June 2011

The recovery from stroke of 154 survivors out of 255 stroke patients was analyzed. The outcomes documented were: discharge from hospital, activities of daily living (ADL) and return to work. A clear improvement in neurological and neuropsychological deficits was seen from the acute stage to three months, and this continued to twelve months, but to a lesser degree. 69% and 78% respectively, of the patients were at home three and twelve months after stroke. Independence in ADL increased from 32% acutely to 62% and 68% by three and twelve months, respectively. Of those gainfully employed prior to stroke, 55% had returned to work after twelve months. As a group, SAH patients seemed to recover better, but, for those that could be age-matched with infarction patients, there was no difference in outcome. Old age, acute stage hemiparesis, impairment of intelligence and memory, visuoperceptual deficits, nonadequate emotional reactions, and living alone all had a major negative influence on outcome. This study suggests that neurological and neuropsychological deficits, as well as emotional reactions, influence the outcomes after stroke, and all should be taken into consideration in prognosis.
Autoradiographic detections of 111indium-labeled platelets in brain tissue sections.
Authors: Obrenovitch T P , Kumaroo K K , Hallenbeck J M
Published: June 2011

Various techniques for detection of blood platelets in tissue section were evaluated in an incremental air embolism model of ischemia in order to further investigate the accumulation of platelets in brains subjected to cell-damaging ischemia. The experimental animals were dogs anesthetized with alpha-chloralose. A new autoradiographic technique was devised that allows precise localization of 111Indium-labeled platelets in brain sections. The technique is described in detail along with some effects of the label on platelet function and behavior. The technique can be performed in conjunction with 14C-iodoantipyrine autoradiographic measurement of blood flow without causing mutual interference or other forms of interaction. This permits the simultaneous investigation of local blood flow and deposition of platelets.
Chemiluminescence in hypoxic brain--the first report. Correlation between energy metabolism and free radical reaction.
Authors: Imaizumi S , Kayama T , Suzuki J
Published: June 2011

The possibility that cerebral ischemia or cerebral hypoxia may initiate a series of free radical reactions in brain tissue lipid constituents was explored by measuring sequential changes in chemiluminescence values and energy metabolism during brain hypoxia in the rat. Brain hypoxia was induced by means of arterial hypoxemia (PaO2 17-22 mmHg), normocapnia (PaCO2 28-38 mmHg) and normotension (MABP 100-140 mmHg). To obtain lowered PaO2, 4% O2--96% N2 mixed gas was used. Analysis of the chemiluminescence spectra for the purpose of luminous mechanism investigation was again attempted. No peroxidation occurred in the pre-hypoxic state since there were no photon counts. Chemiluminescence began to rise in the hypoxic state and remained at a high value in the post-hypoxic state. Specifically in the hypoxic state, the 3 min period showed 231 +/- 35 counts/10 sec X g (n = 5) and the 5 min period showed 154 +/- 62 (n = 19) counts/10 sec X g. In the post-hypoxic state, the 5 min period showed 217 +/- 79 counts/10 sec X g (n = 9) and the 30 min period showed a decrease similar to the pre-hypoxic state. The chemiluminescence spectroanalysis showed five peaks in wavelength at 480 nm, 520-530 nm, 570 nm, 620-640 nm and 680-700 nm. Sequential changes in energy metabolism revealed that hypoxia caused marked brain lactic acidosis, an increase in both ADP and pyruvate, and a fall in glucose. However, all metabolites recovered at 30 min in the post-hypoxic state, which suggests this was reversible brain hypoxia. Sequential changes in chemiluminescence values and energy metabolism imply the occurrence of free radical reaction in the hypoxic and post-hypoxic brain. The spectroanalysis reveals the luminous mechanism as follows: 1 delta g + 1 delta g----23O2 + h mu
Pathogenesis of carotid bifurcation atherosclerosis in cynomolgus monkeys.
Authors: Kaplan J R , Clarkson T B , Manuck S B
Published: June 2011

We report here the effect of diet and social environment on the carotid bifurcation atherosclerosis of 60 adult male cynomolgus monkeys (Macaca fascicularis) fed either an atherogenic diet (AD) or a more "prudent" diet (PD). Animals within each dietary condition lived either in unstable social groupings (which had their memberships reorganized on a regular basis) or in stable groupings. The experiment lasted 22 months, after which animals were necropsied and the extent of atherosclerosis was measured both at the carotid bifurcation and at other arterial sites. Carotid bifurcation atherosclerosis (CBA) was significantly more extensive and severe among animals fed the AD diet. Among these animals, all of which were normotensive, lesion extent was positively associated with both plasma cholesterol concentrations and heart rate response to behavioral stress, and negatively associated with the ability to clear glucose. No experimental variables correlated with the CBA of the PD animals; these lesions, some of which were extensive, were probably pre-existing. The social conditions and individual behavior patterns of the animals had no effect on CBA in either group, despite a pronounced effect on the coronary arteries (CA) of the same animals. While the overall correlation between CBA and CA atherosclerosis was not high, animals with extensive CBA almost always had extensive CA atherosclerosis. The factors influencing CBA in the cynomolgus monkey may be similar to those affecting humans.
Reduction of serum prostacyclin stability in ischemic stroke.
Authors: Stein R W , Papp A C , Weiner W J , Wu K K
Published: June 2011

Prostacyclin is a powerful vasodilator and inhibitor of platelet aggregation that has been implicated to play a role in cerebrovascular disease. Prostacyclin is unstable in aqueous solution and stabilized in serum by binding to an unidentified serum protein as measured by gel filtration. In 15 patients with ischemic stroke we measured the serum prostacyclin binding capacity and the rate of degradation of exogenously added prostacyclin. There was a significant reduction in serum prostacyclin binding capacity and a significant increase in rate of degradation in the patients with ischemic stroke as a whole compared to controls, and in patients with persistent deficits. Decreased serum prostacyclin binding capacity and accelerated rate of prostacyclin degradation in vitro, may reflect an accelerated rate in vivo of prostacyclin degradation, thereby increasing susceptibility to stroke. Since only a small number of patients were investigated, the findings are of a preliminary nature and must be confirmed by further studies with large numbers of patients and appropriate patient controls.
Impact of digital subtraction angiography on carotid evaluation.
Authors: Anderson D C , Fischer G G
Published: June 2011

Impact of digital subtraction angiography by intravenous injection (DSAV) was examined in a private neurology clinic. In the evaluation of threatened stroke, advent of DSAV was associated with reduced use of both traditional noninvasive tests (from 100% of patients to 36%), and conventional arteriograms (from 29% to 4%). Less compelling indications were often prescreened with noninvasive tests; more compelling symptoms usually had initial DSAV. Conventional arteriograms were done for compelling indications and negative or inadequate DSAV. The average cost of evaluation was increased slightly in patients treated medically and reduced greatly in those having surgery. While cost and convenience might support such utilization, issues of quality of evaluation require consideration.
Serum HDL/total cholesterol ratio and blood pressure in asymptomatic atherosclerotic lesions of the cervical carotid arteries in men.
Authors: van Merode T , Hick P , Hoeks P G , Reneman R S
Published: June 2011

One hundred neurologically asymptomatic male subjects (aged 50-69 years), randomly selected through population registers, were screened for atherosclerotic lesions of the cervical carotid arteries, using a high resolution multi-gate pulsed Doppler system. In 93 subjects serum was assayed for total and HDL cholesterol. Besides, cuff arterial blood pressure measurements were made. Twenty-three of these subjects (Group III) were classified as abnormal according to the Doppler investigation (degree of narrowing less than 50% in 78% of the cases). Seven of these 23 subjects also had a history of ischemic heart disease or intermittent claudication. Of the 70 subjects with a normal Doppler examination 16 had a history of ischemic heart disease and/or intermittent claudication (Group II). The remaining 54 subjects served as controls (Group I). The frequency of asymptomatic atherosclerotic lesions of the cervical carotid arteries in the population under investigation was 23%. The HDL/total cholesterol ratio was lower and the frequency of high blood pressure higher in the Groups II and III than in Group I. The findings in this study support the idea that a low serum HDL/total cholesterol ratio and high blood pressure have a high degree of association with atherosclerotic lesions of the cervical carotid arteries. This association is already apparent at an early stage of the disease, i.e. in asymptomatic subjects with a slight to moderate degree of carotid artery narrowing.
Effects of low dose aspirin on platelet function in patients with recent cerebral ischemia.
Authors: Weksler B B , Kent J L , Rudolph D , Scherer P B , Levy D E
Published: June 2011

We tested the antiplatelet effects of low-dose aspirin in patients with occlusive cerebrovascular disease, because conventional dosage aspirin inhibits vascular synthesis of prostacyclin at the same time that it inhibits platelets. The effects on platelet function and thromboxane A2 synthesis of 40 mg of aspirin daily or 40 mg aspirin plus dipyridamole were measured in 23 patients starting within a week after the onset of cerebral ischemia. All patients had normal baseline platelet aggregation responses to four stimuli: arachidonate, epinephrine, adenosine diphosphate and collagen. The generation of thromboxane A2 by platelets, measured as serum thromboxane B2, was also normal. After 3 to 7 days of low dose aspirin therapy, platelet aggregation responses were suppressed to the extent observed with higher dosage aspirin. Serotonin release during platelet aggregation was inhibited by more than 95% and thromboxane B2 levels in clotted blood fell by more than 95%. Responses to aspirin treatment were similar in patients with transient ischemic attacks and in those with stroke and were also similar in both sexes. No differences in platelet responses were observed between patients receiving aspirin alone and aspirin plus dipyridamole. Thus 40 mg aspirin daily inhibited platelet responses as effectively as higher doses of aspirin in patients who had recent cerebral ischemia and showed a cumulative antiplatelet effect.
Long-term assessment of cerebral perfusion following STA-MCA by-pass in patients.
Authors: Tanahashi N , Meyer J S , Rogers R L , Kitagawa Y , Mortel K F , Kandula P , Levinthal R , Rose J
Published: June 2011

A prospective study of mean hemispheric cerebral blood flow (CBF) correlated with clinical status has now been completed for the past 54 months. Thirty-eight patients underwent superficial temporal to middle cerebral artery (STA-MCA) by-pass. They were compared with 22 patients with similar arteriographic lesions and clinical symptoms, treated medically throughout the same interval of time. Assignment to either treatment group was not randomized but depended solely on choice of patient or treating physician. Both groups were matched for age, clinical symptoms, angiographic abnormalities, and CBF values. All patients had proximal occlusion of one internal carotid artery or intracranial occlusive disease of the internal carotid or middle cerebral arteries. CBF measurements and clinical evaluations were repeated at regular intervals up to 54 months following surgery or institution of medical treatment. Mean follow up interval after STA-MCA by-pass was 28.7 months and for medical treatment was 29.7 months. Mean hemispheric CBF values for STA-MCA patients became significantly increased 2 weeks after operation. After that, CBF flow values decreased. At 24 months after surgery, flow values for surgically treated patients were significantly higher than among those treated medically, although there were no differences in flow values between the two groups at 3, 6, 12, 36 and 48 months. Prospective clinical evaluations after STA-MCA by-pass were as follows: 12 (32%) improved with cessation of TIAs and/or neurological improvement, 16 (42%) remained unchanged, 7 (18%) deteriorated (due to new or recurrent strokes) and 3 (8%) expired. Clinical results were the same for medical treatment: 6 (27%) improved, 10 (46%) unchanged, 4 (18%) deteriorated due to new or recurrent stroke, and 2 (9%) expired.
Cerebral distribution of 133-Xe and blood flow measured with high purity germanium.
Authors: Reich T , Rusinek H , Youdin M , Clagnaz M
Published: June 2011

Distribution of cerebral blood flow was measured with an array of 200 ultra-pure germanium radiation detectors and 133-Xe by inhalation. The array "sees" the head as a composite of different subvolumes and enables measurement of the concentration history of tracer every 1-10 sec in each subvolume simultaneously. Subvolume mean flows, (fm), and partition coefficients, lambda m, are derived by compartmental analysis of tissue concentration washout curves. Errors from "cross talk," scalp radiation, "look through," and assumed partition coefficients are eliminated. Average fm adjusted for 40 mm Hg PACO2 in 14 cortical subvolumes (7 right, 7 left) of four normal 21-24 year old controls ranged from 50 to 60 ml/100 cc tissue/min, and lambda m ranged from 0.97 to 1.14. Average fm and lambda m in white matter was 24 ml/100 cc/min and 1.42 - 1.14 respectively. During CO2 inhalation, right and left hemispheric fm increased 6.4% and 5.7%/mm Hg respectively, whereas white matter fm increased 2.2% and 3.4% mm Hg respectively. There was no systematic difference between front and back or dominant vs non-dominant sides. Three 73-84 year old controls had reduced fm and CO2 reactivity in all subvolumes, lambda m was in the same range as in younger controls. Two patients with intracranial cerebrovascular disease showed excellent localization of ischemic subvolumes. One patient with asymptomatic unilateral 98% stenosis of the internal carotid artery had a similar distribution of blood flow in both hemispheres.
Effect of chronic middle cerebral artery stenosis on the local cerebral hemodynamics.
Authors: Naritomi H , Sawada T , Kuriyama Y , Kinugawa H , Kaneko T , Takamiya M
Published: June 2011

In 36 patients with angiographically proven middle cerebral artery (MCA) stenosis, local cerebral hemodynamics were studied employing angiography, 133Xe inhalation regional cerebral blood flow (rCBF) measurements and CT scans. They had transient ischemic attacks in 8 and completed stroke in 28. The patients with less than 50% stenosis (n = 16) had no hemodynamic abnormality in angiographical and rCBF examinations. The infarction in this group was small and located in the basal ganglia area. The patients with 50 to 74% stenosis (n = 9) often revealed a delayed filling of MCA branches in the angiography, however, they showed no significant rCBF reduction. The infarction in this group was also small and located in the basal ganglia area. The patients with 75 to 99% stenosis (n = 11) exhibited a significant flow depression both in angiographical and rCBF examinations. Three of them had large cerebral infarction in the watershed zone or the cerebral cortex. The results of the present study suggest that the hemodynamic effect of MCA stenosis begins to manifest at 50% in grade and becomes apparent at 75%. The danger of hemodynamic crisis as well as the risk of large cerebral infarction may increase when MCA stenosis exceeds 75% in grade.
The influence of noninvasive tests on the selection of patients for carotid angiography.
Authors: O'Leary D H , Clouse M E , Potter J E , Wheeler H G
Published: June 2011

To assess the impact of noninvasive testing of the carotid vessels upon patient management, we analyzed the angiographic findings in 494 patients studied between 1978 and 1983 for suspected extracranial cerebrovascular disease. This longitudinal study revealed two changes in the pattern of angiographic results after introduction of noninvasive testing in the final months of 1979. The proportion of examinations that revealed less than 49% stenosis decreased significantly from 49% in 1978 to 19% in 1983 (p less than 0.001). During the same time, the proportion of examinations identifying 75-99% stenosis increased from 20% to 62% (p less than 0.001). The referring physicians and their patient population appeared to remain unchanged over these years. We believe the decline in patients with little or no disease is a consequence of better patient selection due to screening with noninvasive tests. We credit the increase in patients with 75-99% disease to additional patients identified by noninvasive tests. This study also points out that the role of noninvasive studies will necessarily be restricted because of inherent limitations in the techniques and that clinical judgment will remain the final arbiter with regard to the management of patients at risk for stroke.
Computed tomographic evaluation of cervical carotid plaque complications.
Authors: Culebras A , Leeson M D , Cacayorin E D , Hodge C J , Iliya A R
Published: June 2011

Twenty five patients with manifestations of cerebrovascular ischemic disease were evaluated with high resolution computed tomography of the neck, following intravenous infusion of a contrast agent. Computed tomography images of extracranial carotid arteries revealed atherosclerotic plaque formations and their complications: stenosis, occlusion, ulceration, calcification and mural lucent defects. Histologic analysis of 15 endarterectomy specimens obtained from symptomatic patients who had computed tomography images of discrete lucent defects in carotid plaques demonstrated subintimal hemorrhage of varying age in 13, focal necrosis in 1 and excessive subintimal thickening in 1. It is concluded that lucent images observed in computed tomography of extracranial carotid arteries represent vascular wall lesions within carotid plaques suggestive of subintimal hemorrhage, focal necrosis and/or excessive subintimal thickening. Computed tomography of the extracranial carotid arteries is a relatively non-invasive method that permits the diagnosis of plaque hemorrhages in symptomatic and asymptomatic carotid arteries.
The role of venous digital subtraction angiography of the carotid bifurcation in the evaluation of patients with reversible ischemic attacks or stroke.
Authors: Tans J T , Hoogland P H , Jonkman E J
Published: June 2011

The diagnostic value of venous digital subtraction angiography (VDSA) was evaluated in 168 consecutive patients with suspected or known atherosclerotic lesions of the internal carotid artery. The VDSA findings were correlated with that of arterial angiography (AA) in 50 patients, yielding a sensitivity of 84%, a specificity of 93% and an accuracy of 89%. Correlation of the results of Doppler with that of AA and VDSA provided support for the reliability of VDSA. Clinical data relevant to the selection of angiographic technique was collected, comparing patients who underwent only VDSA, only AA and VDSA followed by AA. The conclusions of our study are: If the image quality is good a normal VDSA practically excludes the presence of surgical lesions in the internal carotid artery and obviates the need for AA. The presence of therapeutically relevant obstructive disease is reliably detected by VDSA, but the degree of obstruction cannot be determined accurately enough to proceed with cerebrovascular surgery without AA. Patients with ischemic events in the carotid territory who are potential candidates for surgery should undergo VDSA when the non-invasive tests are normal and AA when these tests indicate the presence of a stenosis or occlusion.
Cause of cerebral infarction in the carotid territory. Its relation to the size and the location of the infarct and to the underlying vascular lesion.
Authors: Olsen T S , Skriver E B , Herning M
Published: June 2011

Seventy-three patients with acute nonhemorrhagic stroke in the carotid territory were investigated for the cause of the stroke: middle cerebral artery (MCA) occlusion/stenosis or internal carotid artery (ICA) occlusion/stenosis; embolus from the heart and extra-cranial arteries or thrombosis. The study is prospective and consecutive comprising stroke patients below the age of 75 years, admitted in the acute state i.e. within 3 days after stroke onset. Excluded were patients with intracerebral hematoma, subarachnoid hemorrhage, vertebrobasilar stroke and patients in whom another severe disease was present. Cerebral angiography and CT-scan were performed in all patients within one and two days after admission. CT-scan was repeated 2 weeks and 6 months later. Forty percent had MCA occlusion, none had MCA stenosis, 12% had ICA occlusion, 14% had severe ICA stenosis (half of these were associated with MCA occlusion) and 41% were without significant MCA/ICA lesions. Twenty-seven percent had large infarcts with a diameter greater than 3 cm; 34% had medium-sized infarcts with a diameter between 3 and 1.5 cm; 21% had small infarcts with a diameter less than 1.5 cm; 18% had no identifiable infarct on CT-scan. MCA occlusion was responsible for 62% of the large or medium-sized infarcts. ICA occlusion or severe ICA stenosis were responsible for only 27% of the large or medium-sized infarcts. Only 11% of the patients with small or no infarct on CT-scan had significant MCA/ICA lesion.(ABSTRACT TRUNCATED AT 250 WORDS)