bluuebunny/crossref_metadata_2025 huggingface dataset:
CVD mortality, 1968-1978: observations and implications.
Authors: Manton K G , Baum H M
Published: June 2011

U.S. multiple cause of death data were examined for the period 1968-1978. Specifically, the role of cerebrovascular disease mortality as an underlying and associated cause of death was studied. The number of deaths where cerebrovascular disease was cited as the underlying cause of death declined much faster than the number of deaths where cerebrovascular disease was cited as the associated cause of death. This trend is indicative of a possible change in the role of cerebrovascular disease as an associated cause of death. Cause elimination life tables were constructed for cerebrovascular disease as the underlying cause of death and as any cause of death. In the general population, eliminating stroke as a cause of death is projected to have less impact in 1978 than in 1968, for men than for women, and for whites than for nonwhites. Tables were also constructed to examine the life expectancy gains for the group of individuals who died of cerebrovascular disease. For these individuals, the gain in life expectancy at birth ranges from 9 years for white males to 18 years for nonwhite females.
A dynamic concept of middle cerebral artery occlusion and cerebral infarction in the acute state based on interpreting severe hyperemia as a sign of embolic migration.
Authors: Olsen T S , Lassen N A
Published: June 2011

The present study investigates the pathogenesis of focal cerebral hyperemia, its effect on brain tissue and discusses its pathophysiological and therapeutic importance in the light of interpreting severe hyperemia as a sign of arterial reopening probably due to embolic migration. Cerebral angiography, serial CT-scans and serial TC99 -scans were performed in a consecutive group of 73 patients with completed stroke all admitted to hospital within 3 days after stroke onset. When possible the regional cerebral blood flow (rCBF) was studied with the intracarotid Xe 133 injection method. Twenty-nine patients had evidence of middle cerebral artery (MCA) occlusion; rCBF was investigated in 24. Fourteen patients had either occlusion or severe internal carotid artery (ICA) stenosis; rCBF was not measured in these patients. Thirty patients had no angiographical evidence of MCA occlusion, ICA occlusion or severe ICA stenosis; rCBF was investigated in 24. Focal hyperemia was observed in 21 patients but exclusively in the group with evidence of MCA occlusion. Hence, these 21 patients are typical and representative for the group of patients with evidence of MCA occlusion. Hyperemia was found in infarcted as well as in non-infarcted tissue. Apparently, it is the severity of the initial ischemic episode and not the hyperemia that determines whether or not tissue necrosis develops. Interpreting severe hyperemia as a sign of arterial reopening and embolic migration (evidenced by partial reopening affecting only some MCA branches) reopening had occurred in about 1/3 of the patients with MCA occlusion before they were examined 1 to 4 days after stroke onset. Autopsy studies performed in 8 of the patients with MCA occlusion indicate that arterial reopening also takes place in many patients later on (7 of 8). According to this interpretation, hypothetical as it is, the changing position of the embolus is associated with partial or complete reperfusion leading to hyperemia in the initially ischemic brain tissue. The hemodynamic basis for appropriate therapy therefore may change from one day to the next in the acute state of stroke due to MCA occlusion.
The International Cooperative Study on Timing of Aneurysm Surgery--an update.
Authors: Kassell N F , Torner J C
Published: June 2011

The timing of aneurysm surgery is one of the major controversies in the management of subarachnoid hemorrhage. The Cooperative Aneurysm Study is conducting an international epidemiological study to determine mortality and morbidity related to timing of surgery. From January, 1981 to July, 1983 over 3,500 patients have been registered from 68 centers. This preliminary report updates the progress of the study, describes the patient population, and presents overall outcome results.
The natural history of hemispheric and brainstem infarction in Rochester, Minnesota.
Authors: Turney T M , Garraway W M , Whisnant J P
Published: June 2011

All cases of first episodes of brain infarction occurring in the population of Rochester, Minnesota, from 1960 through 1979 were categorized as hemispheric or brainstem (including cerebellar) on the basis of clinical criteria, autopsy evidence, and the results of computed tomography (from 1973 on). Hemispheric infarction was 5 times more frequent than infarction of the brainstem and/or cerebellum. The magnitude of the decline in incidence was the same in each group during the 20-year period of the study. Thirty-day case fatality was similar in each group, but patients with brainstem infarction had a better long-term survival. Functional outcome among survivors of brainstem infarction was also better, 35% having returned to independent living by 1 year after onset compared with 22% of survivors of hemispheric infarction. This may have been a consequence of the higher proportion of residual cognitive and sensory impairments present in survivors of hemispheric infarction.
Cerebral aneurysms and variations in the circle of Willis.
Authors: Kayembe K N , Sasahara M , Hazama F
Published: June 2011

In order to obtain information about the relationship between variations in the circle of Willis and aneurysms, 44 complete circles of Willis with aneurysm were studied macroscopically. The incidence of variations was significantly higher in the aneurysm series than in the control circles without aneurysm. There was a definite correlation between asymmetric proximal segments of the anterior cerebral artery and aneurysms of the anterior communicating artery, and a tendency to correlation was found in the case of asymmetric posterior communicating arteries and aneurysms on the internal carotid artery-posterior communicating artery junction. In the light of these findings it seems likely that through hemodynamic changes variation in the circle of Willis plays some role in the development of cerebral aneurysms.
Prostaglandin synthesis and oedema formation during reperfusion following experimental brain ischaemia in the gerbil.
Authors: Bhakoo K K , Crockard H A , Lascelles P C , Avery S F
Published: June 2011

Regional brain tissue prostaglandin (PG) levels have been measured during ischaemia produced by bilateral carotid occlusion for 1 hour and following restoration of flow. In the normal gerbil, the frontal cortical levels of PGF2 alpha were: 6.7 +/- 1.3 pg/mg and for PGE2: 6.4 +/- 1.1 pg/mg of brain tissue protein. Following 1 hour of ischaemia PGF2 alpha rose to 50.4 +/- 8.3 pg/mg whilst there was only a slight rise in PGE2 (10.7 +/- 1.6 pg/mg). Post ischaemic values for parietal and occipital areas were somewhat higher, but showed the same trend. Within 15 minutes of the restoration of flow there was a massive increase in PGF2 alpha levels which reached a peak at 2 hours (300 pg/mg) and then subsided to control values. PGE2 levels did not change for the first 30 minutes of recirculation, but then rose for the rest of the period of observation. The pattern of cytotoxic oedema resembled PGF2 alpha closely while the Evans blue staining (vasogenic oedema) was similar in time to the PGE2 pattern.
The case against surgery for asymptomatic carotid stenosis.
Authors: Chambers B R , Norris J W
Published: June 2011

Asymptomatic cervical bruits with their implication of underlying carotid artery disease, carry an established but low risk of stroke. In spite of the rising numbers of patients subjected to carotid endarterectomy for this condition, there is little evidence that the benefits outweight the risks. Outcome data from community studies and the current prospective Toronto study of patients with asymptomatic neck bruits indicate that the annual stroke rate is 1-2%, and the annual cardiac death rate is 2-4%. Published data of the results of carotid surgery suggest that surgical risks outweigh any possible benefits, unless a subgroup with spontaneous stroke risk of at least 5% can be identified.
Increased excretion of immunoreactive thromboxane B2 in cerebral ischemia.
Authors: Fisher M , Zipser R
Published: June 2011

Thromboxane B2 (TXB2) is the stable metabolite of thromboxane A2 (TXA2), a potent vasoconstrictor which induces irreversible platelet aggregation. The inhibition of TXA2 by aspirin and other agents has been associated with improved outcome following cerebral ischemia in clinical and laboratory studies. To investigate the relation of TXA2 production to cerebral ischemia, we measured the urinary excretion of TXA2 metabolites in 30 patients with acute cerebral ischemia. Urinary immunoreactive TXB2 for this group of ischemic patients was elevated compared to normals, 1818 +/- 344 pg/mg Cr (mean +/- SE) vs 880 +/- 122 pg/mg Cr (p less than .05). Among various subsets of the ischemic patients, those with severe stroke (2108 +/- 536 pg/mg Cr), large vessel disease (1646 +/- 335 pg/mg Cr), and cardiogenic stroke (2712 +/- 1045 pg/mg Cr) were all significantly elevated. Of the stroke patients, only the males demonstrated this significant elevation. These elevations of urinary immunoreactive TXB2 are consistent with a role for increased platelet activation in the pathogenesis of some forms of cerebral ischemia and suggest that gender differences in arachidonate metabolism may exist for stroke patients.
Effect of small deep hemispheric infarction on the ipsilateral cortical blood flow in man.
Authors: Takano T , Kimura K , Nakamura M , Fukunaga R , Kusunoki M , Etani H , Matsumoto M , Yoneda S , Abe H
Published: June 2011

The effect of small, deep ischemic lesions on the ipsilateral cortical circulation was investigated in 10 patients with persistent mild or moderate neurological deficits due to infarcts in the internal capsule. rCBF studies by the 133Xe intracarotid injection method were performed 14-180 days after the onset of the infarction. The rCBF functional image was made up from the data of 133Xe dynamic images measured by an Anger-type gamma camera and the rCBF values were calculated by the initial slope method. The average value of mean rCBFs (mCBF) in 10 patients was 44.9 +/- 7.1 ml/100g/min (average PaCO2; 39.9 +/- 4.3 mm Hg). In the rCBF functional images, a focal hypoperfusion area was observed in all cases and localized around the central sulcus, especially in the precentral and central areas. Significant decreases of mCBF and the tendency to decrease of the rCBFs in the hypoperfusion focus were noted in the patients with the larger infarcts in comparison with those with the smaller ones. These results suggest that a small, deep ischemic lesion such as a capsular infarct may have remote effects on the ipsilateral cortical circulation, due probably to the damage of a number of fibers passing through the lesion.
Cerebral venous thrombosis--a review of 38 cases.
Authors: Bousser M G , Chiras J , Bories J , Castaigne P
Published: June 2011

A series of 38 patients with angiographically proven cerebral venous thrombosis (CVT) affecting dural sinuses is reported. This study shows that CVT is not rare, that the clinical diagnosis is extremely difficult because of the variable modes of onset and groupings of symptoms, that most CT findings are non specific and that angiography remains the best diagnostic tool. Only 4 patients died, which suggests a more benign outcome than classically described. None of the 23 heparin treated patients died, which indicates that anticoagulants were not harmful in this series.
Effects of indomethacin on rCBF during and after focal cerebral ischemia in the cat.
Authors: Shigeno S , Fritschka E , Shigeno T , Brock M
Published: June 2011

The effect of indomethacin on rCBF was studied in cats anesthetized with Nembutal either under resting conditions or with temporary middle cerebral artery (MCA) occlusion. RCBF was measured by the microsphere method. In control animals (n = 3), indomethacin (4 mg/kg, i.v.) significantly reduced rCBF by about 25% in both cortex (from 44 +/- 6 to 32 +/- 3 ml/100 g/min, p less than 0.001) and white matter (from 36 +/- 4 to 26 +/- 2 ml/100 g/min, p less than 0.001). After MCA occlusion rCBF was markedly decreased in the sylvian region ipsilateral to occlusion (ischemic core) (from 38 +/- 4 to 14 +/- 2 ml/100 g/min in cortex, 4 animals). Although pretreatment with indomethacin (4 mg/kg) (4 animals) 30 min prior to occlusion did not alter rCBF during ischemia, a marked enhancement of reactive hyperemia was observed in the ischemic core immediately upon reperfusion following 2 h occlusion (54 +/- 11 untreated vs 95 +/- 13 treated, p less than 0.05). In the delayed postischemic period, namely 2 h after recirculation, rCBF still remained to be higher in the animals treated with indomethacin (40 +/- 6 untreated vs 96 +/- 9 treated, p less than 0.001). Such an effect of indomethacin for ameliorating postischemic blood flow in both the immediate and delayed period was less prominent in the adjacent area (penumbra) ipsilateral to occlusion. In the contralateral hemisphere, indomethacin caused slight reduction in rCBF during ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)
The morphometry of consecutive segments in cerebral arteries of normotensive and spontaneously hypertensive rats.
Authors: Nordborg C , Fredriksson K , Johansson B B
Published: June 2011

The media cross-sectional area, the media thickness, the internal radius and the ratio between media thickness and internal radius were determined in consecutive sections of extraparenchymal cerebral arteries of 7- and 12-month-old normotensive and spontaneously hypertensive rats. The study included intracranial pial and basal arteries as well as extracranial cervical arteries. In the chronically hypertensive rats the media to radius ratio was consistently higher than in normotensive rats over the entire calibre spectrum investigated (radius 5-400 micron). The increase of the ratio in the extracranial arteries of the hypertensive rats was exclusively due to a thicker media. In the basal intracranial arteries the increase of ratio was due to a thicker media and/or a smaller internal radius in 7- and 12-month-old rats with moderate hypertension (mean arterial pressure, MAP 171 +/- 8 and 177 +/- 7 mm Hg respectively). In 7-month-old rats with severe hypertension (MAP 204 +/- 11 mm Hg) the increase of ratio was mainly due to a smaller internal radius. The observed structural alterations are likely to be of hemodynamic importance.
Reaction of pial arteries and veins to hypercapnia in hypertensive and normotensive rats.
Authors: Johansson B B , Auer L M , Sayama I
Published: June 2011

The lumen diameters of the main cortical surface arteries were continuously monitored through a closed cranial window in spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY). The arterial diameter was significantly smaller in SHR (55 +/- 1 micron) than in WKY (87 +/- 1 micron) during resting conditions as well as during hypercapnic dilatation (87 +/- 2 micron compared to 117 +/- 5 micron). The per cent increase in diameter induced by hypercapnia was larger in SHR (54%) than in WKY (36%), presumably a consequence of the altered vascular wall to lumen ratio. Alpha-adrenoreceptor blockade with yohimbine and phenoxybenzamine had no significant effect on arterial diameter during hypercapnia. The diameters of the largest pial surface veins increased to the same extent in SHR and WKY during hypercapnia (about 10%).
Double-blind controlled trial of prostacyclin in cerebral infarction.
Authors: Martin J F , Hamdy N , Nicholl J , Lewtas N , Bergvall U , Owen P , Syder D , Holroyd M
Published: June 2011

Thirty-two patients with acute cerebral infarction received either prostacyclin or placebo intermittently for 65 hours. Pulse and blood pressure were not altered by prostacyclin. After infusion there was no change in infarct volume or cerebral blood flow in either group. After normalisation for starting values, age and site of cerebral infarction there was a greater than 10% improvement in speech in the prostacyclin group, but minimal changes in neurological score or disability status. Age is related to neurological score at 14 days after stroke by decreasing improvement by 6.8% for each additional 10 years. This study has not been able to demonstrate that prostacyclin is effective in the treatment of ischaemic stroke, but due to the sample size the chance of proving this statistically (the power) was small. Similarly any conclusion that prostacyclin is not effective may be wrong because of the Type II error probability being high.
Graded focal cerebral ischemia in the rat by unilateral carotid artery occlusion and elevated intracranial pressure: hemodynamic and biochemical characterization.
Authors: Busto R , Ginsberg M D
Published: June 2011

Graded transient cerebral hemispheral ischemia was produced in nitrous oxide-anesthetized Wistar rats by a procedure combining unilateral common carotid artery occlusion; elevation of intracranial pressure to 40-45 mm Hg by infusion of mock cerebrospinal fluid; and maintenance of arterial blood pressure at 100-110 mm Hg by controlled hemorrhage. Cerebral perfusion pressure was thus reduced into the ischemic range ipsilateral to carotid occlusion but remained 55-70 mm Hg contralaterally. Regional cerebral blood flow, measured autoradiographically, fell by 85-90% in the ischemic dorsolateral and lateral neocortex, hippocampus and lateral striatum, but remained at 71% of control or higher contralaterally. Metabolite assay revealed a gradient of energy depletion, with profound reductions in ATP and phosphocreatine and marked elevations of lactate in lateral neocortex, lateral striatum, hippocampus and lateral thalamus. Importantly, dorsolateral neocortex proved to be a penumbral zone, with marked lactate elevation comparable to that of lateral cortex, yet only intermediate degrees of ATP and PCr reduction. Contralateral structures were metabolically unaffected apart from mild increases in lactate. The advantages of this focal ischemia model include the consistent topographic distribution of ischemia and its regional gradations of intensity; the avoidance of painstaking intracranial microsurgery and of systemic complications; preservation of intact energy state of the contralateral hemisphere; ease of reversibility of ischemia; and lack of seizures. The consistent metabolic penumbral zone is a unique feature of the model.
Subarachnoid hemorrhage: epidemiology, diagnosis, management, and outcome.
Authors: Bonita R , Thomson S
Published: June 2011

A population-based study of primary subarachnoid hemorrhage in Auckland (population 829,454), New Zealand, identified 180 cases in a two-year period. This represented an age adjusted incidence rate of 10.5 and 18.3 per 100,000 for men and women respectively. Sixty-eight percent of all cases had a proven intracranial aneurysm or arteriovenous malformation, 15% had negative angiographic findings and in the remaining 17%, the presence or absence of a localized lesion was unknown since neither angiography nor autopsy were performed. Twenty-six patients (15%) died before hospitalization and a further 36 patients (20%) died within 48 hours of onset. Only 94 patients (53% of all patients registered) were fit enough to undergo angiography. A surgical operation was carried out on 60 of the 68 patients in whom an aneurysm was confirmed at angiography. The overall case fatality rate was 36% within the first 48 hours, 43% in the first week and 57% at both six months and one year. The high early case fatality rates are similar to those found in previous population-based studies, suggesting that despite the major advances to individual patients from technological advances, the potential contribution of hospital management to the reduction of subarachnoid haemorrhage mortality rates is likely to be limited.
Chronic ocular ischemia and carotid vascular disease.
Authors: Carter J E
Published: June 2011

Venous stasis retinopathy and ischemic oculopathy are ocular manifestations of ischemia in the distribution of the carotid artery. While not as common as transient monocular blindness or retinal arterial emboli, they are readily recognizable and indicate the presence of severe, often bilateral, carotid occlusive disease. Patterns of occlusion vary but usually include complete occlusion of at least one common or internal carotid artery, often accompanied by occlusion or narrowing in the opposite carotid system. The ocular findings in venous stasis retinopathy and ischemic oculopathy indicate ongoing ocular ischemia and may progress to intractable neovascular glaucoma. Therapy, individualized for the specific pattern of occlusive changes, may be directed toward prevention of stroke or may be indicated primarily for the reversal of ocular ischemia and prevention of blindness secondary to neovascular glaucoma.
Caffeine induced changes in cerebral circulation.
Authors: Mathew R J , Wilson W H
Published: June 2011

While the caffeine induced cerebral vasoconstriction is well documented, the effects of oral ingestion of the drug in a dose range comparable to the quantities in which it is usually consumed and the intensity and duration of the associated reduction in cerebral circulation are unknown. Cerebral blood flow was measured via the 133Xenon inhalation technique before and thirty and ninety minutes after the oral administration of 250 mg of caffeine or a placebo, under double-blind conditions. Caffeine ingestion was found to be associated with significant reductions in cerebral perfusion thirty and ninety minutes later. The placebo group showed no differences between the three sets of cerebral blood flow values.
Effects of hematocrit on brain metabolism in experimentally induced cerebral ischemia in spontaneously hypertensive rats (SHR).
Authors: Kiyohara Y , Fujishima M , Ishitsuka T , Tamaki K , Sadoshima S , Omae T
Published: June 2011

Brain tissue lactate, pyruvate, and adenosine triphosphate (ATP) were measured 60 min after bilateral carotid ligation in spontaneously hypertensive rats, of which hematocrit (HCT) was varied by exchanging with isovolemic homologous red cells, plasma or whole blood. Supratentorial lactate of the ischemic brain was increased more in high HCT (greater than or equal to 50%) and less in low HCT (30-39%) compared with normal HCT (40-49%). In very low HCT (less than 30%), however, lactate was increased to further extent compared with any other group of HCT (ANOVA p less than 0.0001). Lactate/pyruvate (L/P) ratio of the ischemic brain showed similar changes, namely U-shaped correlation to HCT. In contrast, supratentorial ATP was decreased more markedly in very low HCT, followed by high and normal HCT, and minimally decreased in low HCT, demonstrating an inverse U-shaped relationship to HCT. Mean arterial pressure and arterial acid-base parameters in ischemic animals did not differ among HCT groups. There were no HCT-related changes of brain metabolites in non-ischemic control rats. These findings indicate that cerebral ischemia following carotid ligation is more severe in high HCT but less in low HCT, probably due to hemodynamic effects of HCT changes. When HCT is reduced to below 30%, however, insufficient oxygen supply to the brain or anemic hypoxia may superimpose on ischemia, resulting in more markedly impairment of brain metabolism. The role of HCT as a cause of cerebral ischemia and its severity is discussed.
Nerve terminal damage in cerebral ischemia: protective effect of alpha-methyl-para-tyrosine.
Authors: Weinberger J , Nieves-Rosa J , Cohen G
Published: June 2011

Mongolian gerbils were treated with alpha-methyl-para-tyrosine methyl ester (AMPT, a tyrosine hydroxylase inhibitor), in order to decrease brain levels of catecholamines. Six hours later, unilateral ischemic stroke was induced by ligation of the left common carotid artery. The delayed degeneration of nerve terminals was studied sixteen hours later by measuring the high-affinity uptake of radiolabeled transmitters by isolated synaptosomes. Dopamine, serotonin and glutamate terminals were studied. AMPT-treated gerbils were compared to untreated (no AMPT) animals; 220 gerbils were studied. AMPT pretreatment (100, 250 and 400 mg/kg) produced a dose-dependent protection of all three types of nerve terminals. In the absence of AMPT pretreatment, the uptake of radiolabeled transmitters by the ischemic hemisphere, expressed as a percentage of that seen in the contralateral (unaffected) side of the brain, was as follows (mean +/- SEM): 27.3 +/- 5.2% for dopamine terminals, 49.5 +/- 6.2% for serotonin terminals, and 42.7 +/- 5.3% for glutamate terminals. Protection was essentially complete at a dose of 400 mg AMPT per kg. The number of animals with significant damage to nerve terminals was reduced from 38.5% in untreated animals to 11.1% in animals treated with AMPT 400 mg/kg. Although the nerve terminals were protected, gerbils still showed the behavioral signs of unilateral stroke due to the permanent occlusion of the left carotid. These results indicate that endogenous dopamine may play a significant role in ischemic damage to nerve terminals in the cerebrum.
Diagnosis of reversible versus irreversible cerebral ischemia by the intravenous administration of naloxone.
Authors: Estañol B , Aguilar F , Corona T
Published: June 2011

Naloxone was given as an I.V. bolus of 0.8 mgs to four groups of patients with stroke: 1) 20 patients with C.T. proven cerebral infarcts of longer than 7 days duration; 2) 20 patients with acute cerebral ischemia of less than 24 hours; 3) 5 patients with C.T. proven intracerebral hemorrhage of less than 24 hours, and; 4) 3 patients with hyperacute cerebral ischemia which occurred during the performance of a cerebral angiogram. The patients with established cerebral infarctions of more than 7 days duration and the patients with intracerebral hematomas had no response to intravenous naloxone. Of 20 patients with acute cerebral ischemia of less than 24 hours duration, 7 had prompt, complete and long-lasting recovery. These patients had no subsequent evidence of cerebral infarct by C.T. scanner 48 hours after the onset of the cerebral ischemia and were asymptomatic when discharged. The 3 patients with hyperacute cerebral ischemia secondary to cerebral angiography had a dramatic response to the injection of naloxone. These findings suggest that intravenous naloxone may differentiate reversible versus irreversible cerebral ischemia.
Pulsed Doppler: an evaluation of diameter, blood velocity and blood flow of the common carotid artery in patients with isolated unilateral stenosis of the internal carotid artery.
Authors: Benetos A , Simon A , Levenson J , Lagneau P , Bouthier J , Safar M
Published: June 2011

Arterial diameter, blood velocity and blood flow of both common carotid arteries were studied in 24 patients with isolated unilateral internal carotid artery stenosis, without any other significant lesion of the carotid system. The methodology used a pulsed Doppler system with two original characteristics: an adjustable range-gated system and a double transducer probe enabling both the arterial diameter and blood velocity to be evaluated. On the involved side, the diameter, the blood velocity and the blood flow were significantly reduced (p less than 0.001) in comparison with the opposite side. The degree of the internal carotid artery stenosis judged on arteriography was negatively correlated with (i) the blood flow of the common carotid artery homolateral to the stenosis (r = -0.78, p less than 0.001); and (ii) the ratio of the common carotid artery blood flow between the involved and the opposite side (r = -0.80, p less than 0.001). The proposed quantitative evaluation can be suitable for the detection and for the follow up of patients with stenosis of the internal carotid artery who do not have any other lesion of the carotid system.
Cardiac abnormalities in stroke patients with negative arteriograms.
Authors: Good D C , Frank S , Verhulst S , Sharma B
Published: June 2011

Sixty-five consecutive patients with recent unequivocal TIA (33) or stroke (32), but nondiagnostic arteriograms, had two-dimensional echocardiograms (2DE) and electrocardiograms (ECG) to determine the incidence of cardiac abnormalities which could cause embolic stroke. Abnormalities were classified according to increasing probability of causing an embolic event: non-specific, possible emboligenic abnormality (PEA) or definite emboligenic abnormality (EA). Although 2DE was abnormal in 33 patients (51%), and ECG in 38 (59%), many abnormalities were nonspecific. Only four patients (6%) had EA on ECG and two (3%) on 2DE. Since one patient had EA on both tests, 2DE identified only one patient (mitral valve prolapse) not already identified by ECG. All patients with EA had a prior history of cardiac disease. PEA was present on ECG in 11 patients (17%), and on 2DE in 25 (38%). There was no correlation between age, CT results, or neurologic symptoms commonly associated with embolic stroke and the presence of EA or PEA on ECG or 2DE. Although TIA and stroke patients with negative arteriograms have a high incidence of abnormalities on ECG and 2DE, the percentage of patients with EA is low, and cardiac history and ECG identify most patients. 2DE provides little additional information.
Changes in cerebral blood flow and metabolism following intraarterial or local administration of nimodipine, before and after experimental subarachnoid hemorrhage in baboons.
Authors: Sahlin C , Delgado T , Owman C , Svendgaard N A
Published: June 2011

Experimental subarachnoid hemorrhage (SAH) was induced in baboons by repeated injections of autologous blood into cisterna chiasmatis and cisterna magna, a total of 14-33 ml being injected over 3-4 days. Cerebral blood flow (CBF; 133xenon clearance) and cerebral metabolic rate of oxygen (CMRO2) were measured before, and 7 days after, the first blood injection. The effect of the calcium channel blocker, nimodipine, used in a commercially available form for clinical application, was studied following continuous i.a. infusion (0.1 microgram X kg-1 X min-1) for an interval of 45 min, and also 20 and 60 min after intrathecal administration of 1 microgram X kg-1. During the infusion experiments, CBF was increased by 25-30% both before and after the cisternal blood injection. CMRO2 was also enhanced, but much less. Nimodipine in doses given did not alter systemic blood pressure. Following intrathecal application, CBF and CMRO2 slightly increased at 20 min only before experimental SAH.
Multicenter retrospective review of results and complications of carotid endarterectomy in 1981.
Authors: Fode N C , Sundt T M , Robertson J T , Peerless S J , Shields C B
Published: June 2011

A multicenter retrospective audit of carotid endarterectomies performed during 1981 was completed with 46 institutions contributing 3,328 cases. Overall, there was a 2.5% risk of transient neurological dysfunction following surgery and a 6% risk of stroke or death. The intra-institutional combined major morbidity and mortality varied from 21% to 0. Those institutions with greater than 700 beds had a statistically lower incidence of stroke or death than did other institutions. The incidence of stroke or death postoperatively was significantly lower for patients who were operated on for amaurosis fugax or for unspecified reasons. Those patients who were operated on for a progressing stroke had a higher incidence of stroke but this group was at greatest risk for stroke without surgery. The incidence of postoperative stroke or death was related to the type of arterial repair; vein patch grafting was statistically better than both fabric patch grafting and primary closure. When all patients who were not monitored during surgery were compared to all patients who had electroencephalographic (EEG) monitoring, there was found to be a significant statistical difference in favor of the EEG group. Endarterectomy combined with coronary artery bypass or simultaneous bilateral endarterectomies had a statistically significant higher incidence of stroke or death than did unilateral carotid endarterectomy.
Acute myocardial and plasma catecholamine changes in experimental stroke.
Authors: Hachinski V C , Smith K E , Silver M D , Gibson C J , Ciriello J
Published: June 2011

Focal cerebral ischemia in humans increases the incidence of cardiac arrhythmias, and serum cardiac enzyme and plasma norepinephrine levels. In addition, systemic administration of catecholamines causes myocardial damage. This suggests that cerebral ischemia may cause myocardial damage as a consequence of elevated plasma norepinephrine levels. Therefore, experiments were done in 23 chloralosed, paralyzed and artificially ventilated cats to investigate the effects of occluding (n = 17) or sham-occluding (n = 6) the left middle cerebral artery on the myocardium and on circulating levels of plasma catecholamines. After occlusion of the middle cerebral artery for 12-22 hr, 41% (7/17) of the hearts had either acute myocardial necrosis (3/7), focal hemorrhage (3/7), or both (1/7). In animals with acute myocardial damage the levels of plasma norepinephrine and epinephrine were significantly increased compared to pre- middle cerebral artery occlusion values (+46 +/- 18% and +142 +/- 45%, respectively). As well, in cats with acute myocardial damage, changes from initial levels of plasma norepinephrine and epinephrine were significantly increased over those of experimental cats without acute myocardial damage. In animals which did not have acute myocardial damage (10/17) the circulating plasma levels of catecholamines were not significantly different from pre-occlusion values. Similarly, sham occlusion did not alter plasma catecholamine levels. These data demonstrate that a percentage of animals subjected to middle cerebral artery occlusion have myocardial damage and an increase in plasma concentration of norepinephrine and epinephrine. This suggests that a rise in plasma catecholamine levels, due to increased sympathetic activity after middle cerebral artery occlusion, may cause myocardial damage.
A reversible type of neuronal injury following ischemia in the gerbil hippocampus.
Authors: Kirino T , Tamura A , Sano K
Published: June 2011

The Mongolian gerbil is known to develop delayed neuronal death in the hippocampus following brief forebrain ischemia (Brain Res 239: 57-69, 1982). The effect of pentobarbital on this slow process of neuronal damage was examined. Immediately following 5 min of bilateral carotid occlusion, pentobarbital (10, 20, or 40 mg/kg) was injected. The control animals received saline injection. Seven days following ischemic insult, animals were perfusion-fixed and the neuronal density in the hippocampal CA1 subfield was counted. Most of the neurons in the CA1 sector survived ischemic insult when pentobarbital was given, whereas most of control group neurons were lost without the treatment. The average neuronal density of 20 mg/kg group was 168.2 +/- 12.3 (SEM) per 1 mm linear length of the CA1 subfield. The density in 40 mg/kg group was 181.1 +/- 14.9. The neuronal density in the whole control group was 34.3 +/- 5.1. The density of unoperated normal gerbils was 212.3 +/- 3.9. This result indicates that the neuronal damage of "delayed neuronal death" is reversible. On the other hand, when pentobarbital was injected 1 hr following ischemia, it showed no effect. The cell change in the CA1 sector, reversible at the initial stage, seems to rapidly become irreversible, while neurons still remain intact morphologically.
Duration of ischemia influences the development and resolution of ischemic brain edema.
Authors: Todd N V , Picozzi P , Crockard A , Russell R W
Published: June 2011

The influence of the duration of ischemia on the development and resolution of post-ischemic brain edema (SG method) was studied in anesthetized rats. Edema developed during ischemia and the amount of edema was related to the duration of ischemia (r = 0.843, p less than 0.001). With recirculation to three hours, the major determinant of the amount of edema was still the duration of the preceding ischemia (p less than 0.001). Resolution of brain edema only occurred following fifteen minutes ischemia. Post-ischemic blood-brain barrier breakdown (14C-AIB, EB albumin) was greatest following longer ischemia. Where present, the BBB leakage was simultaneously to large and small molecules.
Rat middle cerebral artery occlusion: evaluation of the model and development of a neurologic examination.
Authors: Bederson J B , Pitts L H , Tsuji M , Nishimura M C , Davis R L , Bartkowski H
Published: June 2011

We have examined the incidence and size of infarction after occlusion of different portions of the rat middle cerebral artery (MCA) in order to define the reliability and predictability of this model of brain ischemia. We developed a neurologic examination and have correlated changes in neurologic status with the size and location of areas of infarction. The MCA was surgically occluded at different sites in six groups of normal rats. After 24 hr, rats were evaluated for the extent of neurologic deficits and graded as having severe, moderate, or no deficit using a new examination developed for this model. After rats were sacrificed the incidence of infarction was determined at histologic examination. In a subset of rats, the size of the area of infarction was measured as a percent of the area of a standard coronal section. Focal (1-2 mm) occlusion of the MCA at its origin, at the olfactory tract, or lateral to the inferior cerebral vein produced infarction in 13%, 67%, and 0% of rats, respectively (N = 38) and produced variable neurologic deficits. However, more extensive (3 or 6 mm) occlusion of the MCA beginning proximal to the olfactory tract--thus isolating lenticulostriate end-arteries from the proximal and distal supply--produced infarctions of uniform size, location, and with severe neurologic deficit (Grade 2) in 100% of rats (N = 17). Neurologic deficit correlated significantly with the size of the infarcted area (Grade 2, N = 17, 28 +/- 5% infarction; Grade 1, N = 5, 19 +/- 5%; Grade 0, N = 3, 10 +/- 2%; p less than 0.05). We have characterized precise anatomical sites of the MCA that when surgically occluded reliably produce uniform cerebral infarction in rats, and have developed a neurologic grading system that can be used to evaluate the effects of cerebral ischemia rapidly and accurately. The model will be useful for experimental assessment of new therapies for irreversible cerebral ischemia.
The effect of long-term antihypertensive treatment on medial hypertrophy of cerebral arteries in spontaneously hypertensive rats.
Authors: Ibayashi S , Ogata J , Sadoshima S , Fujii K , Yao H , Fujishima M
Published: June 2011

The effects of antihypertensive treatment on the structural changes of middle cerebral arteries (MCA) were studied quantitatively and morphometrically in young spontaneously hypertensive rats (SHR). Fifteen male SHR, 10 weeks of age, were divided into control and experimental groups. In the experimental group, the animals were administered hydralazine and guanethidine for the following 10 weeks. At the age of 20 weeks, mean arterial blood pressure of experimental animals was 177 +/- 9 mm Hg (mean +/- SD), being significantly lower than that of 195 +/- 12 mm Hg in control ones. Media thickness of large (external diameter greater than or equal to 200 micron) and medium sized MCA (150-200 micron) in treated SHR was 12.3 +/- 2.8 and 6.3 +/- 1.1 micron, respectively, being significantly smaller than that of 14.0 +/- 2.2 and 8.5 +/- 2.6 micron, respectively, in control SHR. The media cross-sectional area and the ratio of media thickness to external diameter were also significantly reduced by antihypertensive treatment. In the smaller vessels (75-150 micron), however, vascular morphometry revealed no difference between the two groups. Long-term antihypertensive treatment during the early phase of hypertension attenuates the development of medial hypertrophy in large cerebral arteries.
Calcific cerebral emboli and aortic stenosis: detection of computed tomography.
Authors: Kapila A , Hart R
Published: June 2011

Embolism with brain infarction rarely complicates calcific aortic stenosis (CAS). We report a case with severe CAS where the patient experienced multiple embolic strokes immediately following retrograde heart catheterization. Calcific emboli in the cerebral arteries were demonstrated by computed tomography (CT).
The prognosis of carotid siphon stenosis.
Authors: Wechsler L R , Kistler J P , Davis K R , Kaminski M J
Published: June 2011

We retrospectively reviewed the clinical course and angiograms of 15 patients with carotid siphon stenosis of 50% or greater. Fourteen had less than 50% stenosis at the origin of the ipsilateral internal carotid artery, and one had a greater degree of stenosis but underwent endarterectomy after an initial angiogram. Angiograms were examined for evidence of hemodynamic abnormalities in addition to residual lumen diameter. Seven patients initially had TIAs, 5 had strokes, and 3 were asymptomatic. In an average followup of 51 months (range 4-123 months) subsequent cerebral ischemic events occurred in 6 (40%), but only 1 had a stroke with a persisting neurological deficit that could be directly attributed to the siphon stenosis. Stenoses were hemodynamically significant by angiography in 5 of 7 TIA patients, and only 1 of 5 stroke patients. The incidence of subsequent ischemic events in this study was similar to 2 previous studies of siphon stenosis, however in this study most of the events ipsilateral to the siphon stenosis were TIAs or minor strokes. The association of hemodynamic angiographic abnormalities and initial TIAs but not strokes suggests that the mechanism producing ischemic symptoms may differ in patients with TIA and stroke who have carotid siphon stenosis.
Diagnosis of transient ischemic attacks: improvement of interobserver agreement by a check-list in ordinary language.
Authors: Koudstaal P J , van Gijn J , Staal A , Duivenvoorden H J , Gerritsma J G , Kraaijeveld C L
Published: June 2011

To try and improve the interobserver agreement for the diagnosis of TIA, we used a checklist in which the symptoms were recorded in plain language, instead of in abstract diagnostic terms such as amaurosis fugax. Criteria for a diagnosis of TIA were similarly phrased and recommended to all observers. Eight senior neurologists and ten neurology residents interviewed 72 patients in random pairs. In 64 cases the observers agreed on the diagnosis (kappa value = 0.77). After a short discussion between the two observers the agreement increased to a maximum (kappa = 1.0). However, in 29 of the 144 interviews the diagnosis would have been different, had the recommended criteria been fully applied. In 28 of these the observer had diagnosed TIA on insufficient evidence. Six "misinterpretations" led to disagreement for the diagnosis and only these were corrected by the observers during their discussion. The present design has led to a maximal agreement for the diagnosis of TIA between two observers, but the agreement between such a pair and the common diagnostic criteria was not yet ideal. The precision of the diagnosis could be improved if details of the required symptoms are discussed in general as well as for each patient.
Subarachnoid hemorrhage and granulomatous angiitis of the basilar artery: demonstration of the varicella-zoster-virus in the basilar artery lesions.
Authors: Fukumoto S , Kinjo M , Hokamura K , Tanaka K
Published: June 2011

A 70-year-old man, with regional herpes zoster (C2) of 10 weeks duration, died following subarachnoid hemorrhage caused by the rupture of an aneurysm in the basilar artery. Granulomatous angiitis, with multinucleated giant cells, was found at autopsy in the wall of the aneurysm. Electron microscopy of the basilar artery disclosed intracytoplasmic viral particles with an envelope which measured 150-220 nm in diameter. Immunohistochemistry studies revealed varicella-zoster-virus-related antigen in the cytoplasm and/or in the nucleus of histiocytes in the vessel wall. These findings suggest that varicella-zoster virus may be linked to the development of granulomatous angiitis.
Early changes of experimentally induced cerebral aneurysms in rats: scanning electron microscopic study.
Authors: Kojima M , Handa H , Hashimoto N , Kim C , Hazama F
Published: June 2011

To obtain information about the early changes of experimentally induced cerebral aneurysms in rats, the luminal surface of branching areas of their cerebral arteries was examined with a scanning electron microscope. At the branching sites of major cerebral arteries in the control animals, the intima just distal to the apex markedly protruded into the lumen forming a linear bank-like intimal pad. Along and distal to this pad, there was a shallow long groove (juxta-apical groove). Such grooves were much deeper and wider in experimental animals than those in the control rats. By studying various stages of early aneurysmal changes, cerebral aneurysms were proven to develop from such grooves. In deep juxta-apical grooves and small aneurysms, round regenerated endothelial cells with a large number of microvilli were diffusely present. Degenerated cells with balloons and craters were observed intermingled with such regenerated cells. Interendothelial gaps were also seen. The present study showed the complex structure of the apex of arterial bifurcation in rats, including bank-like intimal pads. Such complex structures of the branching sites were considered to be responsible for the initiation of cerebral aneurysms due to endothelial injury possibly caused by turbulent flow there.
Significance of EEG changes at carotid endarterectomy.
Authors: Blume W T , Ferguson G G , McNeill D K
Published: June 2011

Visually apparent EEG changes associated with clamping the internal carotid artery appeared in 55 of 176 consecutive patients (31%) undergoing carotid endarterectomy without shunt. Attenuation of higher frequency activity was the most common change. Changes were moderate in 33 patients (19%) and major in 22 (12.5%). Major changes usually commenced earlier than less severe alterations. EEG changes resolved within 10 minutes of clamp release in 36 of 55 patients (65%) after an average clamp time of 36.25 minutes. Changes occurred more commonly when pre-operative EEGs were abnormal contralateral to clamping and when the contralateral carotid artery was more than 90% stenosed. Of the inhalational anesthetics employed with nitrous oxide and oxygen, isoflurane was associated with the lowest incidence of clamp-associated EEG change. Post-operative strokes occurred in 2 of 22 patients (9%) with major clamp-associated EEG changes, none of 33 patients with moderate changes and none of 121 without changes. However, the mechanism of this relationship remains in doubt.
Transcranial Doppler measurement of middle cerebral artery blood flow velocity: a validation study.
Authors: Bishop C C , Powell S , Rutt D , Browse N L
Published: June 2011

Measurement of intracranial arterial blood flow velocity is a new technique with potentially a number of very useful applications. This study validates the technique by comparing it to cerebral blood flow (CBF) measured using intravenous Xenon133 and extracranial clearance recording. We have measured the middle cerebral artery (MCA) blood flow velocity in 17 symptomatic patients with the EME TC 264 transcranial Doppler velocimeter and compared these measurements to the ipsilateral hemispheric cerebral blood flow measured with an intravenous Xenon133 technique (Novo Cerebrograph 10A). Measurements were made at rest and during hypercapnia. The absolute measurement of MCA velocity and hemispheric CBF showed a poor correlation (r = 0.424, p less than 0.01) due to wide between-patient variations at rest but the blood flow response to hypercapnia, expressed as a reactivity index, showed a good correlation (r = 0.849, p less than 0.001). Thus changes in MCA velocity reliably correlate with changes in cerebral blood flow but the absolute velocity cannot be used as an indicator of CBF.