bluuebunny/crossref_metadata_2025 huggingface dataset:
An Analysis of the Effects of Nicotine on the Cerebral Circulation of an Isolated, Perfused, in situ Cat Brain Preparation
Authors: INGENITO ALPHONSE J. , BARRETT JAMES P. , PROCITA LEONARD
Published: June 2011

To determine the effects of nicotine HCl on the cerebral circulation of the cat, without the complicating actions of the drug at other sites in the body, the drug was perfused at concentrations of 1, 10 and 100 µg/ml through a vascularly isolated, perfused in situ cat brain preparation. Cats having selective section of cranial nerves 9, 10, 11 and 12 and the cervical sympathetic trunks comprised various experimental groups. Nicotine was also perfused through an isolated, denervated hindlimb of the same cat for comparative purposes. Nicotine caused only a mild and transient vasoconstriction of the cerebral circulation, mediated primarily by stimulation of the superior cervical ganglia, and a small direct cerebral vasoconstrictor component. An acute tolerance to the cerebral vasoconstrictor effects of repeated increments of nicotine was also observed. The cerebral vasoconstrictor effect of nicotine was diminished in the presence of intact vagi, suggesting a cerebral vasodilator role for these nerves. In contrast, the effect of nicotine on the denervated hindlimb vasculature was a weak but sustained vasodilation. The mechanism of action of nicotine on the cerebral circulation is discussed along with the relevance of these findings to the potential health hazards of tobacco smoking in individuals with cerebrovascular insufficiency.
A Population Survey of Symptoms Suggestive of Transient Ischemic Attacks
Authors: MULES JANET , HENDERSON MAUREEN , KULLER LEWIS , TONASCIA SUSAN , DIAMOND EARL , LILIENFELD ABRAHAM
Published: June 2011

A sample of the Baltimore population was interviewed in order to determine the frequency of symptoms suggestive of transient cerebral ischemic attacks. Respondents were interviewed in their homes. A history of ten symptoms which may have occurred within the past two years was elicited. Of the 6,830 individuals that were interviewed, 52% had no symptoms and approximately 10% had three or more symptoms. The frequency of symptoms did not increase substantially with advancing age between ages 45 to 74 or very markedly by sex and race. Individuals reporting a history of cardiovascular disease, stroke or diabetes had a substantially higher frequency of symptoms. Also the frequency of symptoms appeared to be higher in the less-educated groups.
Reassessment of Anticoagulant Therapy in Various Types of Occlusive Cerebrovascular Disease
Authors: MILLIKAN CLARK H.
Published: June 2011

Precise use of categorical terms and definitions is mandatory in discussing the use of anticoagulants in treating occlusive cerebrovascular disease. The components of the temporal profile of the disease are described.

Six reports have appeared which describe the results of anticagulant therapy in transient cerebral ischemic attacks. From these six studies it is concluded that anticoagulant therapy significantly decreased the risk of cerebral infarction in patients who had attacks of transient focal cerebral ischemia.

In the few carefully performed investigations of the use of anticoagulant for acute progressing stroke the evidence points to the lack of progression in patients receiving treatment when compared to individuals not getting such drugs.

There continues to be a definite difference of opinion about the results of anticoagulant therapy in completed stroke. If anticoagulant is to be administered on a long-term basis, it must be considered dangerous and every effort made to control the level of anticoagulant action precisely. Hypertension must be effectively controlled.
Adrenergic Blockade of Hypocapnic Cerebral Arterial Constriction
Authors: FRASER RICHARD A. R. , STEIN BENNETT M. , POOL J. LAWRENCE
Published: June 2011

Hypocapnic constriction of the basilar and vertebral arteries was produced and pharmacologically modified (by intrathecal administration) in nine Rhesus monkeys. The arteries were then removed and studied with a catecholamine fluorescent technique. Alterations in
P

CO

CO
2

were associated with significant changes in the caliber of large arteries. Mere depletion of the periarterial norepinephrine stores did not prevent hypocapnic vasoconstriction. The latter was reversed, however, by alpha adrenergic blockade (phenoxybenzamine). The alpha adrenergic receptor appears to be a mediating site for hypocapnic constriction of the intracranial vessels. We have proposed that the alpha receptor may be
H
+ sensitive so that changes in pH alter the responsiveness of the adrenergic receptor to transmitter substances.
The Brain in Hereditary Hemorrhagic Telangiectasia
Authors: REAGAN THOMAS J. , BLOOM WILLIAM H.
Published: June 2011

While neurological symptoms are often mentioned in reports of families with hereditary hemorrhagic telangiectasia (HHT) and are frequently assumed to be due to vascular anomalies of the central nervous system, documentation of such anomalies is surprisingly rare. Two cases of surgically treated symptomatic cerebral vascular malformations in HHT have been published previously. In addition, there are three descriptions of vascular anomalies discovered at autopsy in the brains of neurologically asymptomatic patients with HHT available in the literature. A complete postmortem examination of a patient with a symptomatic cerebral vascular anomaly associated with HHT has not been recorded previously.

The patient reported in this paper presented with seizures and underwent surgical resection of infarcted brain tissue associated with a venous angioma. He died six months later and, at autopsy, was found to have multiple "cryptic" venous angiomas of the brain. Hypoxic damage to brain tissue related to small venous angiomas is one mechanism whereby these lesions may become symptomatic. Hemorrhage may also occur. Neurological symptoms in patients with HHT cannot be assumed to be due to cerebral vascular anomalies, and consideration must be especially given to the complications of pulmonary arteriovenous fistula such as polycythemia, embolism, and abscess.
Comparison of Anticoagulation and Surgical Treatments of TIA. A Review and Consolidation of Recent Natural History and Treatment Studies
Authors: FRANK GILBERT
Published: June 2011

Combined results of selected studies of the natural history and therapeutic results in patients with TIA indicate that anticoagulation therapy is clearly worthwhile in the prevention of completed strokes during the first 40 months after onset. Surgery is somewhat less valuable, but preferable to nihilism, which is associated with new completed strokes in 19% of patients and death in 20% of patients followed for an average of 40 months from onset of TIAs. The incidence of death from all causes is remarkably similar in both treated and untreated patients during this follow-up period, suggesting that fears of increased mortality in patients treated with anticoagulants are either unfounded or compensated by decreased mortality from occlusive strokes.
Clinical Prognosis Correlated with Hemispheric Blood Flow in Cerebral Infarction
Authors: MEYER JOHN STIRLING , KANDA TADASHI , FUKUUCHI YASUO , SHIMAZU KUNIO , DENNIS EDWARD W. , ERICSSON ARTHUR DALE
Published: June 2011

In 44 patients with acute unilateral cerebral infarction, there was reduction of hemispheric blood flow (HBF) and metabolism in the healthy hemisphere (phenomenon of diaschisis) as well as in the diseased hemisphere in patients in all age groups (30 to 70 years of age). In patients with symptoms present for three weeks or longer, the decrease in HBF in the healthy hemisphere was less than during the acute stage of infarction. The HBF in the healthy hemisphere of the younger patients approached normal values months or years after the stroke but remained reduced in older patients, probably reflecting diffuse as well as focal cerebrovascular disease. When the severity and outcome of the neurological deficit was correlated with the blood flow and metabolism of the diseased hemisphere, it was apparent that HBF in patients with transient ischemic attacks and more prolonged but reversible neurological deficit was greater than in those who had sustained severe, permanent neurological deficit.
Antifibrinolytic Activity During Administration of Epsilon-Aminocaproic Acid
Authors: NIBBELINK DONALD W.
Published: June 2011

Utilizing an in vitro method for activated and nonactivated whole blood clotlysis determinations, the antifibrinolytic effect of epsilon-aminocaproic acid therapy was evaluated. Initially, the induced antifibrinolytic activity diminished within two hours after the previous dose. Continuing therapy for three to six days resulted in sustained fibrinolytic inhibition.
Effect of nimodipine on canine cerebrovascular responses to 5-hydroxytryptamine and potassium chloride after exposure to blood.
Authors: Tsuji T , Cook D A
Published: June 2011

The stainless steel cannula inserting method was used to investigate the blocking effects of nimodipine on vascular responses to intraluminal administration of 5-hydroxytryptamine (5-HT) or potassium chloride (KCl) before and after application of abluminal blood containing thrombin in isolated and perfused canine basilar arteries. A transient elevation of perfusion pressure was observed initially, and during the course of the experiment the perfusion pressure gradually increased. Nimodipine significantly depressed both transient and prolonged changes of perfusion pressure. Dose-dependent vasoconstriction induced by 5-HT was significantly enhanced, while that evoked by KCl was significantly attenuated for up to 8 hours after the application of blood. Pretreatment with nimodipine inhibited vasoconstriction to 5-HT less effectively than to KCl both before and after application of blood. The proportion of the 5-HT-induced vasoconstriction, which was sensitive to nimodipine, was reduced after application of blood, while no such change was observed in the responses to KCl. It is suggested that the augmentation of cerebrovascular responses to 5-HT in the early stage of subarachnoid hemorrhage may be mediated mainly by changes in intracellular calcium utilization rather than by the increase of calcium influx through nimodipine-sensitive channels.
The MICROSTROKE expert system for stroke type diagnosis.
Authors: Spitzer K , Thie A , Caplan L R , Kunze K
Published: June 2011

MICROSTROKE is a prototype expert system designed to categorize and diagnose stroke types based on clinical information. The knowledge base of MICROSTROKE includes information from large stroke registries. The system first queries the physician-user for details of the patient's history, information about the onset of stroke, accompanying symptoms, and pertinent neurologic findings and then sums the individual data items, factors in the a priori odds, and arrives at the probabilities of different stroke types for a given patient. Specific diagnosis of stroke type includes thrombosis, embolus, lacune, intracerebral hemorrhage, and subarachnoid hemorrhage. Stroke type diagnoses by MICROSTROKE were correct in 72.8% of 250 cases in the Hamburg Stroke Data Bank. MICROSTROKE runs on any MS-DOS microcomputer and is intended as a practical aid for physicians not fully familiar with the diagnosis of stroke types.
Reduction of hyperthermic ischemic acidosis by a conditioning event in cats.
Authors: Chopp M , Tidwell C D , Lee Y J , Knight R , Helpern J A , Welch K M
Published: June 2011

We investigated the effects of multiple episodes of cerebral ischemia on intracellular brain pH using in vivo phosphorus-31 nuclear magnetic resonance spectroscopy. Four cats were subjected to two 16-minute episodes of complete global cerebral ischemia 6 hours apart; the second episode occurred under hyperthermic conditions (mean +/- SD body temperature 40.8 +/- 0.4 degrees C). Intracellular pH in these four cats was compared with that in nine cats subjected to a single 16-minute episode of complete global cerebral ischemia under hyperthermic conditions (mean +/- SD body temperature 40.6 +/- 0.2 degrees C). Intracellular pH during hyperthermic recirculation was significantly (p less than 0.03) greater in cats subjected to a previous ischemic event than that in cats subjected to only a single hyperthermic ischemic event. We speculate that the induction of heat shock proteins by an initial ischemic event may protect brain tissue from further ischemic insult.
Reversible middle cerebral artery embolization in dogs without intracranial surgery.
Authors: Purdy P D , Devous M D , White C L , Batjer H H , Samson D S , Brewer K , Hodges K
Published: June 2011

Using dogs, we developed an intravascular model for reversible middle cerebral artery occlusion that does not involve intracranial surgery or enucleation. Using silicone plastic plugs with a suture embedded within them, we embolized the middle cerebral artery in 19 dogs via the cervical carotid artery. The free end of the suture remained accessible in the neck, and after variable dwell times traction was placed on the suture and the plug was withdrawn. Placement of the plug in the middle cerebral artery produced ischemia in the basal ganglia. The degree and distribution of cortical ischemia were variable as evidence by the pathologically documented scattered nature of infarcts that resulted when the plug was left permanently in the middle cerebral artery and when it was removed after 1 or 2 hours. Angiography demonstrated occlusion of the middle cerebral artery with the plug in place as well as reperfusion when the plug was withdrawn. This modification of a previously described model of middle cerebral artery occlusion provides an opportunity to study structural, physiologic, and biochemical events occurring in acutely hypoperfused cerebral tissue as well as critical changes leading to irreversible injury without the disadvantages of surgical manipulation required by all previous models of reversible cerebral ischemia.
A comparison of risk factors and prognosis for transient ischemic attacks and minor ischemic strokes. The Oxfordshire Community Stroke Project.
Authors: Dennis M S , Bamford J M , Sandercock P A , Warlow C P
Published: June 2011

In a community-based study of transient ischemic attack and stroke, we identified 184 cases of transient ischemic attack and 213 cases of first-ever minor ischemic stroke. A comparison of age, sex, and prevalence of coexistent vascular diseases and risk factors revealed no major differences between the two groups. The risk of further stroke and of further stroke and/or death was greater in patients with minor ischemic stroke although the difference was significant only for the latter. The apparent differences in prognosis could largely be accounted for by the favorable prognosis of patients with amaurosis fugax among those with transient ischemic attack. Although for some purposes it may be useful to distinguish transient ischemic attacks from minor ischemic strokes, the similarity of the two groups suggests that in many situations, including in clinical trials of treatments for the secondary prevention of strokes, the arbitrary distinction between them could be dispensed with.
Intracerebral hemorrhage in stroke patients anticoagulated with heparin.
Authors: Babikian V L , Kase C S , Pessin M S , Norrving B , Gorelick P B
Published: June 2011

To characterize the clinical features of patients with acute cerebral infarction who sustained intracerebral hemorrhage related to heparin anticoagulation, we describe 10 patients and review reports of 16 cases. Cardiac-source embolism was identified in seven (70%) of the 10 patients and consisted of atrial fibrillation in six of the seven. The middle cerebral artery territory was affected in nine patients (90%), with moderate-sized or large infarcts by clinical and computed tomographic criteria. The interval between stroke onset and intracerebral hemorrhage was less than 72 hours in 80% of the patients. Intracerebral hemorrhage occurred less than or equal to 24 hours after the time heparin was started in 80% of the patients. The activated partial thromboplastin time closest to the time of intracerebral hemorrhage was greater than 2 x control in seven patients. Our findings in the 10 patients are similar to those of the 16 cases previously reported and suggest that heparin-related intracerebral hemorrhage occurs early after stroke onset, usually with moderate-sized or large infarcts, and with excessive anticoagulation in some patients.
Effect of MCI-186 on ischemia-induced changes in monoamine metabolism in rat brain.
Authors: Oishi R , Itoh Y , Nishibori M , Watanabe T , Nishi H , Saeki K
Published: June 2011

We examined the effects of MCI-186 (3-methyl-1-phenyl-2-pyrazolin-5-one), a novel free radical scavenger and an inhibitor of ischemia-induced brain edema, on monoamine metabolism in the brains of both normal and ischemic rats. In normal rats, 3 mg/kg i.v. MCI-186, a dose that prevents ischemic brain edema, had no significant effect on brain concentrations of dopamine, norepinephrine, 5-hydroxytryptamine, or their metabolites. After the injection of 5 microliters of 3% polyvinyl acetate into the left internal carotid artery, concentrations of 3,4-dihydroxyphenylacetic acid and homovanillic acid markedly increased, but that of norepinephrine decreased, in the left telencephalon of embolized rats compared with control rats injected with vehicle; the concentration of 5-hydroxyindoleacetic acid also increased slightly. These effects were maximal 2 hours after embolization. The turnover rate of dopamine between 6 and 8 hours after embolization was significantly higher but that of norepinephrine was slightly lower than that in vehicle-treated rats. When rats were treated with 3 mg/kg i.v. MCI-186 immediately after the injection of polyvinyl acetate, the embolization-induced changes in monoamine metabolism were less marked. Our results suggest that MCI-186 attenuates ischemia-induced changes in brain monoamine metabolism, probably due to its free radical scavenging action, although it has no marked effect in normal rats.
Nonvalvular atrial fibrillation as a cause of fatal massive cerebral infarction in the elderly.
Authors: Yamanouchi H , Tomonaga M , Shimada H , Matsushita S , Kuramoto K , Toyokura Y
Published: June 2011

By studying 3,408 consecutive autopsied elderly patients, we found that two thirds of the 132 massive cerebral infarctions (86) were embolic, of cardiac origin. Embolic infarction associated with nonvalvular atrial fibrillation was seen in 48 cases (36%), half due to the first stroke. Embolic infarction associated with heart disease other than nonvalvular atrial fibrillation was seen in 23 cases (17%), and that from nonbacterial thrombotic endocarditis was seen in 15 cases (11%). Thrombotic infarction or infarction of nonembolic cardiac origin was found in only 39 cases (30%). Of 56 patients with fatal massive cerebral infarction who died less than or equal to 2 weeks after their stroke, 25 (45%) had embolic strokes associated with nonvalvular atrial fibrillation. Our study shows that nonvalvular atrial fibrillation is a very important cause of fatal massive cerebral infarction in the elderly.
Short-term tranexamic acid treatment in aneurysmal subarachnoid hemorrhage.
Authors: Wijdicks E F , Hasan D , Lindsay K W , Brouwers P J , Hatfield R , Murray G D , van Gijn J , Vermeulen M
Published: June 2011

Antifibrinolytic treatment for 4 weeks after a subarachnoid hemorrhage has been shown to have no effect on outcome since a reduction in the rate of rebleeding was offset by an increase in ischemic events. To determine if a shorter course (4 days) of antifibrinolytic treatment before the expected onset of ischemic complications might reduce the rate of rebleeding yet avoid ischemic complications, we prospectively studied a series of 119 patients with subarachnoid hemorrhage; 479 patients with subarachnoid hemorrhage from our previous randomized double-blind study (238 treated with placebo, 241 with long-term tranexamic acid) served as historical control groups. At 3 months' follow-up, the outcome of patients treated with short-term tranexamic acid was not different from that of patients treated with long-term tranexamic acid. The rate of rebleeding (24 of 119, 20%) was near that with placebo (56 of 238, 24%). In contrast, the rate of cerebral infarction (33 of 119, 28%) was almost identical to that after long-term tranexamic acid (59 of 241, 24%), although mortality from cerebral infarction was reduced. Compared with historical control groups, treatment with tranexamic acid for 4 days fails to reduce the incidence of rebleeding but still increases the rate of cerebral infarction.
Increased neuropeptide Y concentrations in cerebrospinal fluid from patients with aneurysmal subarachnoid hemorrhage.
Authors: Suzuki Y , Sato S , Suzuki H , Namba J , Ohtake R , Hashigami Y , Suga S , Ishihara N , Shimoda S
Published: June 2011

We investigated the possible relation between neuropeptides and cerebral vasoconstriction in samples of ventricular or cisternal cerebrospinal fluid from 14 patients with subarachnoid hemorrhage. Neuropeptide Y, calcitonin gene-related peptide, atrial natriuretic peptide, and pituitary polypeptide 7B2 were present in the cerebrospinal fluid of these patients. Concentrations of calcitonin gene-related peptide and 7B2 were not significantly different from those in control subjects, but that of atrial natriuretic peptide was significantly lower. Although the mean concentration of neuropeptide Y was not significantly higher than control, consecutive determinations showed an increase 6-11 days after the onset of subarachnoid hemorrhage. An initially high 7B2 concentration decreased gradually, although half the patients showed a second increase greater than 10 days after the onset. Considering the well-recognized vasoconstrictive effect of neuropeptide Y, it is possible that this increase in its concentration in the cerebrospinal fluid plays a role in the pathogenesis of the cerebral vasospasm that is often seen after subarachnoid hemorrhage.
Prolonged pharyngeal impaction of dentures following stroke.
Authors: Fort S , Batty G M , Wilkins W E
Published: June 2011

Dysphagia is a well-recognized complication of stroke. We report two cases of dysphagia in stroke patients caused by the pharyngeal impaction of dental prostheses. Radiologic identification of such impaction is unreliable due to the increasing use of radiolucent material in dental prostheses. We recommend direct or indirect laryngoscopy to exclude foreign body impaction in all patients complaining of dysphagia.
Syphilis detection in cerebrovascular disease.
Authors: Kelley R E , Bell L , Kelley S E , Lee S C
Published: June 2011

To determine the importance of syphilis testing in cerebrovascular disease, we prospectively assessed 218 consecutive patients with either transient ischemic attack or completed stroke. The results from this study group were compared with those from a control group of 150 neurological patients without cerebrovascular disease. Of 275 patients from both groups specifically tested by the fluorescent treponemal antibody-absorption test, 34% of the study group were seropositive compared with 18% of the controls (chi 2 = 7.7, p less than 0.01). Fifty-four percent of the patients with a positive fluorescent treponemal antibody-absorption test underwent a cerebrospinal fluid examination; meningovascular syphilis was detected in one (0.4%) of these. This patient was a homosexual male with antibodies to the human immunodeficiency virus; a second patient, with possible meningovascular syphilis, also had antibodies to this virus. Despite the relatively high rate of syphilis seropositivity noted in our study group, syphilis was not found to be a common cause of cerebrovascular disease; therefore, routine screening is seen to be of low diagnostic yield. Attention to patients who are at higher risk for syphilitic infection, patients with clinical features suggestive of meningovascular syphilis, and the proper choice of serologic studies can help make the assessment of syphilis seropositivity more clinically appropriate and cost effective.
Cerebrovascular disease and functional outcome after coronary artery bypass surgery.
Authors: Harrison M J , Schneidau A , Ho R , Smith P L , Newman S , Treasure T
Published: June 2011

A series of patients undergoing coronary artery bypass surgery was studied prospectively to see if angiographic evidence of cerebrovascular disease proved predictive of the incidence of neuropsychological deficit 8 days or 8 weeks after surgery. In 47 patients, intravenous digital subtraction angiography was carried out preoperatively to assess the presence and severity of atheromatous changes in the carotid arteries; 51% had evidence of vessel wall disease and 17% had stenosis of at least one carotid artery in the neck, although only one patient had severe narrowing. Overall, 77% of these 47 patients showed a neuropsychological deficit as defined by a significantly reduced score in at least two of 10 tests administered 8 days after surgery. Eight weeks after surgery 36% still showed a deficit. The incidence of neuropsychological deficit was not significantly greater among those patients with angiographically visible carotid artery disease. The mechanism of surgery-related cognitive impairment is briefly discussed in the light of these findings.
A flavonoid inhibitor of 5-lipoxygenase inhibits leukotriene production following ischemia in gerbil brain.
Authors: Ban M , Tonai T , Kohno T , Matsumoto K , Horie T , Yamamoto S , Moskowitz M A , Levine L
Published: June 2011

Leukotrienes C4 and D4 are arachidonic acid metabolites that constrict blood vessels and enhance vascular permeability; their biosynthesis is initiated by the reaction of arachidonic acid with 5-lipoxygenase enzyme. After bilateral carotid artery occlusion for 15 minutes and reperfusion of the gerbil brain for 15 minutes, we determined the brain tissue concentrations of leukotrienes C4 and D4 by radioimmunoassay; they had increased from a baseline concentration of less than 1 to a mean +/- SEM concentration of 12.8 +/- 3.9 pmol/g brain. We also studied the effect of a flavonoid 5-lipoxygenase inhibitor on leukotriene production in the reperfused gerbil brain. A water-soluble flavonoid (5-hexyloxy-3',4'-dihydroxy-6,7-dimethoxyflavone 4'-disodium phosphate) was administered intravenously at a dose of 200 mg/kg body wt; 15 minutes later, both carotid arteries were occluded. The enhanced production of leukotrienes C4 and D4 in the reperfused brain was reduced by approximately 80% (from a mean +/- SEM of 12.8 +/- 3.9 to 2.2 +/- 1.3 pmol/g brain) in the presence of the 5-lipoxygenase inhibitor. The flavonoid did not affect the production of prostaglandin D2, the concentration of which also increased in the reperfused ischemic brain.
Destinations of stroke patients discharged from the Montreal area acute-care hospitals.
Authors: Mayo N E , Hendlisz J , Goldberg M S , Korner-Bitensky N , Becker R , Coopersmith H
Published: June 2011

The destinations of stroke patients after discharge from acute-care hospitals were studied to ascertain the current use of health care resources. The 1984-1985 acute-care hospital discharge listings for the province of Quebec were consulted to identify 3,045 adults of the Montreal area who were discharged, deceased or alive, with a primary or secondary diagnosis of stroke. The relation between the length of stay (i.e., the time to death or discharge to long-term care, rehabilitation, or home) and the explanatory variables (age, sex, neighborhood socioeconomic status, type of stroke, and university affiliation of the discharging hospital) was assessed using Cox's proportional hazards models. Older patients and those with hemorrhagic strokes had the highest risk of death. However, patients with hemorrhagic strokes were more likely to survive if admitted to a university teaching hospital. Older patients, those with nonhemorrhagic strokes, and those admitted to university teaching hospitals were more likely to be discharged to long-term care. A greater proportion of patients discharged to rehabilitation centers were young, lived in a high-socioeconomic-status neighborhood, and had suffered a nonhemorrhagic stroke. Patients had a significantly higher probability of going home if they were young, had had a nonhemorrhagic stroke, had been admitted to a university teaching hospital, or were male.
Effects of a new thyrotropin-releasing hormone derivative on behavioral changes after focal cerebral ischemia in rats.
Authors: Yamamoto M , Tamura A , Kirino T , Shimizu M , Sano K
Published: June 2011

We observed the effects of a new thyrotropin-releasing hormone derivative, YM-14673 (N alpha-[[(S)-4-oxo-2-azetidinyl]carbonyl]-L-histidyl-L-prolinamide dihydrate), on behavioral changes in rats for 3 weeks after focal cerebral ischemia. Under halothane anesthesia, the left middle cerebral artery was occluded via a transretro-orbital approach. YM-14673 was administered just after the operation and once a day for 3 weeks. Neurologic deficits, including hemiplegia and abnormal posture, and disturbance of passive avoidance learning were present in solvent-treated control rats for the entire 3 weeks. YM-14673 at 0.1 or 0.3 mg/kg i.p. or 1 mg/kg p.o. significantly accelerated the recovery of neurologic deficits and ameliorated cognitive disturbance compared with the solvent-treated controls although the drug at 0.1 and 0.3 mg/kg i.p. did not influence the size of the ischemic infarct. YM-14673 mitigated the behavioral disturbances in this model of chronic focal cerebral ischemia. We also discuss the suitability of this model for the evaluation of drugs.
Pathogenesis of transient ischemic attacks and stroke in baboons.
Authors: Fritz V U , Levien L J
Published: June 2011

We describe a series of experiments in which a subhuman primate model was used to create temporary and permanent cerebral ischemia by three separate mechanisms. In the first group of five baboons, a hemodynamic model was produced by creating unilateral and bilateral carotid stenotic lesions of varying degrees with and without associated reduction in systemic perfusion pressure. Only global ischemic changes and no focal changes resulted. In the second group of three baboons, a macroembolic model was produced by introducing solid particulate material into the extracranial circulation. No reversible contralateral focal neurologic changes resulted. In the third group of 11 baboons, cerebral ischemia was produced by introducing agents known to cause platelet aggregation (arachidonic acid, adenosine diphosphate, and collagen) into the extracranial arterial circulation. Arachidonic acid caused seizures, adenosine diphosphate caused severe postural hypotension, and only collagen fibrils produced a picture resembling a transient ischemic attack. We propose a theory that intravascular activation of the prostaglandin cascade by chemical initiation may result in the pathophysiologic changes of transient cerebral ischemia.
Anterior choroidal artery territory infarction: a small vessel disease.
Authors: Bruno A , Graff-Radford N R , Biller J , Adams H P
Published: June 2011

To investigate the cause(s) of infarction in the anterior choroidal artery territory, we studied 31 patients (18 men, 13 women) aged 19-82 (mean 58) years, with infarction in this territory documented by computed tomography. All patients were evaluated within 30 days after infarction and had carotid artery studies (arteriography in 17, duplex ultrasound in 14). Fifteen patients had echocardiography. Risk factors for atherosclerosis were chronic hypertension in 20 patients, smoking in 17, diabetes in 10, age greater than 69 years in eight, and elevated serum cholesterol concentration in three. The percentage of patients with extracranial carotid artery stenosis (four of 31, 13%) and the severity of stenosis (mild in two, moderate in two) were similar to that reported in neurologically asymptomatic individuals. The percentage of patients with intracranial carotid artery stenosis (one of 17, 6%) or potential cardiac sources of emboli (two of 31, 6%) was also low. Our findings suggest that infarctions in the anterior choroidal artery territory usually result from small-vessel disease. Associated carotid artery stenosis and potential sources of cardiac emboli are rare and may be coincidental.
Mitochondrial function after asphyxia in newborn lambs.
Authors: Rosenberg A A , Parks J K , Murdaugh E , Parker W D
Published: June 2011

We examined mitochondrial oxidative function 5 minutes and 2 hours after a gradual asphyxial insult in newborn lambs. We subjected 16 ventilated newborn lambs to 75-90 minutes of hypoxia and hypercarbia that resulted in bradycardia and systemic hypotension over the final 15 minutes of the insult. At the end of asphyxia, the lambs were resuscitated and returned to control ventilator settings. Samples of brain were removed 5 minutes (n = 8) and 2 hours (n = 8) after asphyxia. Each group of eight lambs was subdivided into those less than 3 or greater than 3 days old to evaluate the effect of age on postasphyxia mitochondrial function. After classification into nonsynaptic and synaptic mitochondria, mitochondrial respiration (oxygen consumption) was measured using five different substrates. Data from asphyxiated lambs were compared with that from a control group of ventilated nonasphyxiated lambs (n = 8). In the lambs less than 3 days old, there was significant depression of mean +/- SEM nonsynaptic mitochondrial state 3 (adenosine diphosphate-dependent) respiration to 29.5 +/- 5.2% of control with four of the five substrates and of state 4 respiration to 33.7 +/- 0.9% of control with three of the five substrates 5 minutes after asphyxia. By 2 hours after asphyxia, mean +/- SEM nonsynaptic mitochondria state 3 respiration increased to 70.4 +/- 6.4% of control while state 4 respiration increased to 58.2 +/- 4.5% of control. In contrast, lambs greater than 3 days old exhibited no inhibition of nonsynaptic mitochondrial function after asphyxia.(ABSTRACT TRUNCATED AT 250 WORDS)
Incidence, mortality, and case-fatality rate of stroke in northern Israel.
Authors: Epstein L , Rishpon S , Bental E , Brook G , Tamir A , Gross B , Szwarc M , Manelis J , Pillar T
Published: June 2011

We studied the incidence and mortality of stroke in northern Israel to determine possible reasons for the differences previously found in mortality from this condition between the sex and ethnic groups in Israel as a whole. We identified 1,149 cases of stroke during 1984. While the age-standardized incidence was higher in men, the case-fatality rate was twice as high in women. After controlling for ethnic origin, we found that incidence was higher only in men of Western origin, while the female rates were higher in women of Asian and North African extraction. The case-fatality rate was substantially higher in women in all ethnic groups. These differences, especially in relation to the case-fatality rate, have important implications for health services in relation to both possible preventive action and to management of the acute disease phase.
Prostaglandin profiles in relation to local circulatory changes following focal cerebral ischemia in cats.
Authors: Hanamura T , Shigeno T , Asano T , Mima T , Takakura K
Published: June 2011

We explored the temporal and topographic relations between local cerebral blood flow and regional brain prostaglandin profile following prolonged or transient occlusion of the middle cerebral artery in cats. Each experimental group was subjected to a sham operation, prolonged ischemia, or recirculation. Local cerebral blood flow was measured by the hydrogen clearance method. Following in situ freezing, cortical samples were obtained from each gyrus for determination of prostaglandin (PG) F2 alpha, PGE2, 6-keto-PGF1 alpha, and thromboxane (TX) B2 concentrations by radioimmunoassay. During prolonged ischemia, the concentrations of PGF2 alpha and PGE2 within the middle cerebral artery territory were significantly increased. Immediately after recirculation, there was a prominent but transient increase in PGF2 alpha and PGE2 in gyri that had been exposed to moderate ischemia (perifocal area). By contrast, the increases in these prostaglandins were slow and less prominent in gyri that had been exposed to severe ischemia (the focal area). The concentration of 6-keto-PGF1 alpha did not change during prolonged ischemia but transiently increased following recirculation in both the focal and perifocal areas. The TXB2 concentration did not change in any experimental group. Our study revealed a homogeneous increase in the regional brain content of PGE2 or PGF2 alpha in spite of the heterogeneous reduction of local cerebral blood flow during prolonged ischemia. Following recirculation, the focal and perifocal areas exhibited different patterns of prostanoid content. No correlation was found between local cerebral blood flow and the regional concentration of any prostaglandin examined.
Progressing ischemic stroke in a homozygote with variant antithrombin III.
Authors: Ueyama H , Hashimoto Y , Uchino M , Sasaki Y , Uyama E , Okajima K , Araki S
Published: June 2011

A 31-year-old woman developed disturbance of consciousness and left hemiparesis. Cerebral computed tomograms showed a low-density area in the right temporal lobe that extended to the right parietal and left frontal lobes as her clinical symptoms worsened. The diagnosis of familial variant of antithrombin III (AT-III) was based on decreased biologic activity and a normal immunologic level of AT-III in this patient and in her family members. Transfusion of normal AT-III concentrate led to a striking clinical recovery. Blood coagulation studies revealed that nine of 13 family members had decreased biologic AT-III activity and that the patient herself was the only homozygote with variant AT-III. We conclude that variant AT-III, especially in a homozygote, seems to be one cause of ischemic stroke in young adults and that simultaneous measurement of both the biologic and immunologic activities of AT-III is necessary to detect it.
Hypesthetic ataxic hemiparesis in a thalamic lacune.
Authors: Lee N , Roh J K , Myung H
Published: June 2011

Right hemiparesis with an ipsilateral hypesthesia and ataxia developed in a 57-year-old man. Magnetic resonance imaging showed a left thalamic lacune bordering the medial portion of the posterior limb of the internal capsule. This finding implicated some pathogenetic mechanism of ataxic hemiparesis.
Recovery of impaired endothelium-dependent relaxation after fluid-percussion brain injury in cats.
Authors: Ellison M D , Erb D E , Kontos H A , Povlishock J T
Published: June 2011

The effect of a moderate level of fluid-percussion brain injury on acetylcholine-induced cerebral arteriolar vasodilation was examined for 12 hours after trauma in anesthetized cats equipped with cranial windows. The cats were then perfused with aldehydes, and the pial arteries were prepared for electron microscopy. Immediately after brain injury, the normal vasodilator response to topical application of acetylcholine was converted to vasoconstriction. By 4 hours after trauma, the ability of small pial arterioles (diameters less than 100 microns) to dilate after acetylcholine application had returned to the pretrauma level and was observed to be normal at both 8 and 12 hours after trauma (p less than 0.05). The vasodilator response of large caliber arterioles (diameters greater than or equal to 100 microns) at 4, 8, and 12 hours after injury was reduced relative to the pretrauma response but was significantly improved relative to their response at 30 minutes after trauma (p less than 0.05). Moreover, the response of large vessels at 4, 8, and 12 hours in injured animals was equal to that observed in noninjured control animals assessed at 4, 8, and 12 hours after window implantation. At 12 hours after injury, the ultrastuctural characteristics of both large and small vessels resembled their preinjury state. These data suggest that the impairment of acetylcholine-induced endothelium-dependent relaxation observed in cats after fluid-percussion brain injury is not irreversible but returns to normal (small arterioles) or exhibits significant recovery (large arterioles) within 4 hours after injury.
Leukoaraiosis and intracerebral hematoma.
Authors: Selekler K , Erzen C
Published: June 2011

We studied 33 consecutive patients with computed tomographic findings of decreased density in the periventricular white matter (leukoaraiosis). Computed tomograms in five (aged 56-75 years) of the 33 demonstrated intracerebral hematoma. The hemorrhages were situated in the thalamic area in four and in the parietotemporal area in one patient. These five patients were hypertensive and had signs characteristic of parenchymal hemorrhage. Three of the five patients had progressive dementia prior to the ictus, and two of the three also had a history of single or multiple strokes. There was no significant difference in the clinical findings of hematoma patients with or without leukoaraiosis.
Effects of a new thyrotropin-releasing hormone analogue administered in rats 1 week after middle cerebral artery occlusion.
Authors: Yamamoto M , Tamura A , Kirino T , Hirakawa M , Shimizu M , Sano K
Published: June 2011

We observed the effects of a new thyrotropin-releasing hormone analogue, YM-14673 (N alpha-[[(S)-4-oxo-2-azetidinyl]carbonyl]-L-histidyl-L-prolinamide dihydrate) on behavioral changes in 26 rats subjected to middle cerebral artery occlusion. The administration of 0.1 mg/kg i.p. YM-14673 was started 1 week after occlusion and was repeated daily for 2 weeks. YM-14673 significantly accelerated the recovery of neurologic deficits and ameliorated the disturbance of passive avoidance learning. Thus, YM-14673 improved behavioral response in a model of chronic focal cerebral ischemia. The availability of a chronic middle cerebral artery occlusion model for the evaluation of drugs is also discussed.
Incidence and prognosis of subarachnoid hemorrhage in a Japanese rural community.
Authors: Kiyohara Y , Ueda K , Hasuo Y , Wada J , Kawano H , Kato I , Sinkawa A , Ohmura T , Iwamoto H , Omae T
Published: June 2011

Twenty-six first episodes of subarachnoid hemorrhage occurred among 1,621 Hisayama residents aged greater than or equal to 40 years during the 22-year follow-up of a prospective study. Subarachnoid hemorrhage was confirmed by both clinical and autopsy findings. The average annual incidence (96.1/100,000 population) was 3-13 times higher than any previously reported and steeply increased with age in both sexes, being 2.3 times higher for women than for men after adjusting for age. Nine patients (35%) died less than or equal to 8 hours after the onset of subarachnoid hemorrhage. None was correctly diagnosed on the death certificates, and four of the nine (44%) were misdiagnosed as intracerebral hemorrhage. We found the survival rate of patients suffering subarachnoid hemorrhage to be much lower than previously reported because we detected a large number of sudden deaths due to subarachnoid hemorrhage through the high rate of autopsy in our cohort (81.4%).
Hemorrhagic stroke development in spontaneously hypertensive rats fed a North American, Japanese-style diet.
Authors: Smeda J S
Published: June 2011

The purpose of my study was to assess a North American, Japanese-style diet commercially available from Zeigler Brothers (Gardners, Pennsylvania) with respect to the initiation of stroke development in 34 stroke-prone spontaneously hypertensive rats (spSHR) and in 14 stroke-resistant spontaneously hypertensive rats (srSHR). Nineteen spSHR fed the diet containing 4% NaCl and 0.75% K+ (low-K+ diet) from weaning had an accelerated rate of stroke development (mean +/- SEM age at death 15.3 +/- 0.5 weeks). The same diet containing 2.11% K+ (high-K+ diet) increased the mean lifespan of 15 spSHR by 39% but did not prevent stroke. The locations of hemorrhagic lesions were similar in the groups of spSHR fed high- and low-K+ diets, being nearly equally divided between the territories of the anterior, posterior, and middle cerebral arteries. The 14 srSHR fed the low-K+ diet exhibited 50% mortality at 66 weeks of age. However, in the srSHR fed the low-K+ diet, death did not result from hemorrhagic stroke. The differing incidence of stroke between the spSHR fed high- and low-K+ diets and between spSHR and srSHR fed the low-K+ diet could not be explained on the basis of differing blood pressures. Compared with spSHR fed the low-K+ diet, both srSHR fed the low-K+ diet and spSHR fed the high-K+ diet exhibited higher drinking and urine excretion rates and elevated plasma K+ levels. My study indicates the availability of a commercial North American diet that produces a predictable high incidence of stroke within a compressed time period in spSHR but not in srSHR. This diet would be useful in studies attempting to determine the events preceding and leading to the development of stroke and in determining the genetic factors responsible for stroke resistance.
Cardiac evaluation of the patient with stroke.
Authors: Sirna S , Biller J , Skorton D J , Seabold J E
Published: June 2011

Coronary artery disease and ischemic cerebrovascular disease are leading causes of morbidity and mortality in the United States. Coronary artery disease often coexists with asymptomatic carotid artery atherosclerosis, transient ischemic attacks, or ischemic stroke. Numerous studies have shown that mortality from all forms of ischemic cerebrovascular disease is primarily due to coronary artery disease. Thus, there is increasing interest in identifying coronary artery disease in patients with cerebrovascular disease, including those without clinical manifestations of heart disease. We review the use of current noninvasive techniques to detect coronary artery disease and present practical approaches to screen for ischemic heart disease. Current diagnostic imaging methods for potential cardioembolic sources of cerebral infarction are also discussed.
Ischemic brain rescue by transvenous perfusion in baboons with venous sinus occlusion.
Authors: Frazee J G , Jordan S E , Dion J E , Kar S , Vinuela F , Rand R W , Corday E
Published: June 2011

We studied brain retroperfusion in nine adult baboons. Experiments in four baboons determined techniques and the safety of retroperfusion, and experiments in three baboons determined the ability of retroperfusion to reverse cerebral ischemia. Two baboons died before retroperfusion. Arterial blood was continuously circulated by an external pumping system from one femoral artery into the intracranial sinuses through specially designed balloon-tipped catheters placed percutaneously into the sigmoid sinuses bilaterally. The balloons intermittently occluded the sinuses. Ischemia was produced by occluding the left middle cerebral artery. Standard and computed electroencephalography with topographic mapping monitored the onset and reversal of ischemia. Retroperfusion rate exceeded 50 ml/min with a mean intrasinus pressure increase of 27 (0-149) mm Hg in all seven experiments. Venograms demonstrated complete or partial filling of the superior sagittal sinus in each experiment. Four experiments without ischemia established maximal balloon occlusion cycles, retroperfusion rates, and sinus pressure changes. These four baboons were neurologically normal after retroperfusion; two had normal magnetic resonance imaging scans. Ischemic changes, detected by electroencephalography following middle cerebral artery occlusion, were reversed with retroperfusion in all three ischemia experiments. Autopsies in the seven baboons demonstrated no parenchymal hemorrhage or edema. Our results suggest that further investigation of retroperfusion, and possibly retroinfusion of agents for cerebral protection, is warranted.