bluuebunny/crossref_metadata_2025 huggingface dataset:
Cerebral infarction associated with lupus anticoagulants--preliminary report.
Authors: Hart R G , Miller V T , Coull B M , Bril V
Published: June 2011

Hypercoagulability may contribute to stroke in young adults. Lupus anticoagulants (LA) were identified in six patients (4%) of 145 young adults with cerebral infarction. The clinical features of the 6 patients in this survey plus an additional patient from another institution with LA-associated stroke are presented. Four had systemic lupus erythematosus and 3 had idiopathic LA; all had mild thrombocytopenia. In 2 patients, no other conditions associated with stroke were discovered after thorough evaluation. Recurrent arterial thrombosis occurred in 4 of 7 patients during an average of two years of follow-up. Evidence suggests that inhibition of prostacyclin formation may occur with LA, promoting a prothrombotic state.
Cerebral hemorrhage associated with phenylpropanolamine in combination with caffeine.
Authors: Mueller S M , Muller J , Asdell S M
Published: June 2011

Phenylpropanolamine (PPA) is a drug that has been associated with serious side effects including stroke. It is often combined with caffeine in diet preparations and "look-alike" pills. In order to determine if PPA/caffeine can lead to stroke in normotensive and/or hypertensive rats, we administered the combination in six times the allowed human dose calculated on a per weight basis for the rats two times per day for five days. Subarachnoid and cerebral hemorrhage was noted in 18% of the hypertensive rats. A single PPA/caffeine administration (same dose) lead to acute hypertension in both the normotensive and hypertensive animals. These results suggest that PPA/caffeine can lead to cerebral hemorrhage in previously hypertensive animals when administered in greater than the allowed dosage. An acute elevation in blood pressure may be a contributing factor.
The role of adenosine in CBF increases during hypoxia in young vs aged rats.
Authors: Hoffman W E , Albrecht R F , Miletich D J
Published: June 2011

The role of adenosine in the regional cerebral blood flow (rCBF) response to hypoxia was evaluated in young (6 month) and aged (26-28 month) F344 rats using theophylline, an adenosine antagonist. Regional CBF was measured with radioactive microspheres under control anesthetized conditions (70% N2O, 30% O2) and at two levels of hypoxia (CaO2 = 8.7-9.0 ml . 100ml-1 and 3.2-3.7 ml . 100ml-1). Without theophylline infusion, CBF increases were similar between young and aged rats during moderate hypoxia but were increased more in young during severe hypoxia. Intracerebrovascular theophylline infusion significantly attenuated the increase in CBF during both moderate and severe hypoxia and decreased the difference between young and aged rats. Theophylline infusion produced no significant effect on the increase in CBF produced by hypercapnia, indicating the specificity of the treatment for hypoxic induced CBF changes and adenosine release. Intracerebrovascular infusion of adenosine had no effect on CBF, presumably due to the presence of the blood brain barrier. The results suggest that adenosine plays a major role in CBF increases during both moderate and severe hypoxia and in the difference in response to hypoxia between young and aged rats.
Brain and plasma proteins in spinal fluid as markers for brain damage and severity of stroke.
Authors: Strand T , Alling C , Karlsson B , Karlsson I , Winblad B
Published: June 2011

Forty well-defined acute stroke patients were investigated for some cerebro-spinal fluid (CSF) markers of cerebral damage. Myelin-basic protein (MBP), tau-fraction, albumin, IgG and transferrin were analyzed on two early occasions after onset of clinical symptoms. Patients with transitory ischaemic attack (TIA) had normal values for MBP both at first and second lumbar puncture. Patients with cerebral infarction and haemorrhage had mean MBP concentrations higher than normal at both lumbar punctures. In cerebral infarction there was a significant increase in MBP from the first to the second lumbar puncture. Patients with intracerebral haemorrhage showed the highest mean MBP values and MBP was markedly elevated already at the first lumbar puncture, suggesting different mechanisms of destruction of nervous tissue in cerebral infarction and bleeding. The amount of MBP was also significantly correlated to the visibility of the cerebral lesion at CT-scan and to the short-term outcome of the patients. The tau-fraction, indicating damage to grey matter, was higher than normal in the majority of patients with cerebral infarction and TIA. The concentration of MBP increases with the extent of brain lesion and a high value indicates a poor short-term prognosis for the patient. This study shows that the brain specific MBP in CSF is a useful marker of cerebral damage in acute cerebrovascular disease.
Eicosapentaenoic acid: effect on brain prostaglandins, cerebral blood flow and edema in ischemic gerbils.
Authors: Black K L , Hoff J T , Radin N S , Deshmukh G D
Published: June 2011

Eicosapentaenoic acid prevents platelet aggregation and inhibits arachidonate conversion into thromboxane A2 and prostaglandins. Consequently eicosapentaenoic acid might protect the brain from the ischemia that follows cerebral arterial occlusion. We studied the effect of eicosapentaenoic acid on cerebral ischemia in anesthetized gerbils. Ischemia was produced by bilateral carotid occlusion for 10 min, followed by reperfusion for 60 min, in gerbils fed either a standard diet (control) or a diet supplemented with menhaden fish oil for 2 months. The menhaden fish oil contained 17 mole % eicosapentaenoic acid. Regional cerebral blood flow was measured by the hydrogen clearance method and brain water by the specific gravity technique. In control animals cerebral blood flow was decreased 30 and 60 min after reperfusion (p less than .001) and brain water was increased (p less than .001). In the experimental group cerebral blood flow did not fall during reperfusion and edema did not appear. Brain prostaglandins and thromboxane were measured by radioimmunoassay. PGF2 alpha, PGE2, 6-keto PGF1 alpha and TXB2 increased after severe ischemia and reperfusion. The synthesis of brain diene prostaglandins was not altered by eicosapentaenoic acid. Our study indicates that eicosapentaenoic acid prevented post-ischemic cerebral edema and hypoperfusion, without affecting the levels of brain diene prostaglandin and thromboxane.
Comparative studies of regional CNS blood flow autoregulation and responses to CO2 in the cat. Effects of altering arterial blood pressure and PaCO2 on rCBF of cerebrum, cerebellum, and spinal cord.
Authors: Sato M , Pawlik G , Heiss W D
Published: June 2011

Autoregulation and CO2 responses were investigated concurrently in cerebrum, cerebellum, and spinal cord of 19 cats by means of hydrogen clearance. Under ketamine and nitrous oxide anesthesia at normal systemic mean arterial blood pressure (MABP 123 +/- 18.4 mmHg, mean +/- standard deviation) blood flow was 86 +/- 30.0 ml/100 g/min in the cerebrum, 48 +/- 13.6 ml/100 g/min in the cerebellum, and 46 +/- 18.7 ml/100 g/min in the spinal cord. During normocapnia (PaCO2 27-33 mmHg) for every mmHg of PaCO2 variation an average flow change of 1.7 ml/100 g/min was found in the cerebrum, corresponding change rates in the cerebellum and in the spinal cord were 1.1 and 0.9 ml/100 g/min/mmHg, respectively. Thus, the effect of carbon dioxide appears to be positively correlated with the normal level of regional perfusion and metabolism. Flow values within 10% of control were recorded in the cerebrum at MABPs ranging from 79 to 123% of normal blood pressure, 53 to 146% in the cerebellum, and 83 to 128% in the spinal cord. These results suggest greater susceptibility to pressure dependent ischemia of cerebrum and spinal cord, with relative resistance of the cerebellum.
Prolongation of bleeding time and inhibition of platelet aggregation by low-dose acetylsalicylic acid in patients with cerebrovascular disease.
Authors: Boysen G , Boss A H , Odum N , Olsen J S
Published: June 2011

Platelet aggregation and bleeding time was measured in 43 cerebrovascular patients participating in a controlled double-blind study of low-dose acetylsalicylic acid. In 19 patients with satisfactory inhibition of the platelet aggregation obtained by 50 to 70 mg acetylsalicylic acid per day the bleeding time averaged 11.2 minutes in contrast to 7.0 minutes in the placebo group, p less than 0.001. This study confirms our previous findings of platelet inhibition by low-dose acetylsalicylic acid in patients with cerebrovascular disease. The prolongation of the bleeding time demonstrates that we are dealing not merely with an in vitro phenomenon but with a significant in vivo effect. The study provides the rationale for clinical evaluations of low-dose acetylsalicylic acid in stroke prophylaxis.
Stroke in south Alabama: incidence and diagnostic features--a population based study.
Authors: Gross C R , Kase C S , Mohr J P , Cunningham S C , Baker W E
Published: June 2011

This study has attempted to identify all persons from an area of southern Alabama who had a stroke in 1980 and were hospitalized. Data were gathered on disease onset, clinical course, laboratory results, history of risk factors, and outcome. The age-adjusted incidence rates for initial stroke were 109 per 100,000 for whites and 208 per 100,000 for blacks. Age-specific rates were higher in blacks than whites, and highest for black females. The distribution of cases by type of stroke was: atherothrombotic (6%), embolic (26%), lacunar (13%), infarction of unspecified origin (40%), parenchymatous hemorrhage (8%), subarachnoid hemorrhage (6%), and unidentified type (1%). Blacks had higher incidence rates for hemorrhages, and black females had the highest incidence rate for lacunar stroke. The overall stroke incidence rates in this series were not significantly higher than those from prior population studies, suggesting that southern Alabama is not part of the so-called "Stroke Belt" area of the southeastern United States.
Study of platelet activation in migraine: control by low doses of aspirin.
Authors: D'Andrea G , Toldo M , Cananzi A , Ferro-Milone F
Published: June 2011

Although platelet activation is known to occur during migraine attacks, the cause-effect relationship remains to be determined. This problem was approached by studying the possible occurrence of platelet activation in vivo in headache-free periods of subjects affected by common or classic migraine and, subsequently, by verifying the possibility of its pharmacological control through administration of a classic anti-aggregation drug such as aspirin (ASA). The plasma levels of beta-thromboglobulin (beta-TG) and platelet factor 4 (PF4), indices of the occurrence of platelet activation in vivo, were therefore first assayed in both groups of migraine sufferers in the absence of therapy and then during the administration of aspirin (50 mg/daily). In the group of 15 patients affected by classic migraine, basal plasma levels of beta-TG and PF4 were significantly higher than control subjects. On the other hand, only beta-TG plasma levels were significantly higher in the group of 18 patients affected by common migraine. Patients suffering from classic migraine showed a high incidence of platelet activation (greater than 90%) in comparison with common migraine patients (approximately 33%). This suggests that platelet activation occurs in vivo in migrainous patients also during headache-free periods. Administration of aspirin to the patients affected by common and classic migraine caused a decrease in plasma beta-TG and PF4 concentration. Consequently, pharmacological treatment with aspirin in adequate dose may prove to be helpful in diminishing the vascular side-effects known to occur in migraine sufferers.
Chronic antihypertensive treatment in the rat reverses hypertension-induced changes in cerebral blood flow autoregulation.
Authors: Vorstrup S , Barry D I , Jarden J O , Svendsen U G , Braendstrup O , Graham D I , Strandgaard S
Published: June 2011

Cerebral blood flow (CBF) autoregulation was studied in renal hypertensive rats receiving chronic antihypertensive treatment. Young Wistar Kyoto rats (WKY) were made hypertensive by the Loomis procedure i.e. partial infarction of one kidney with contralateral nephrectomy. Systolic tail blood pressure was measured at 2-week intervals throughout the study. After two months, by which time the rats had been severely hypertensive for 5-6 weeks, antihypertensive treatment was begun; reserpine, dihydralazine and hydrochlorothiazide were administered in the drinking water. Blood pressure fell rapidly to normotensive levels and remained so. Following two months of antihypertensive treatment, the lower blood pressure limit of CBF autoregulation was studied during controlled bleeding. In age-matched untreated renal hypertensive WKY, the lower limit of autoregulation was in the mean arterial pressure range 90-109 mm Hg, as compared to 50-69 mm Hg in age-matched normotensive WKY. In contradistinction to the untreated rats, the treated rats had a normal lower limit of autoregulation, i.e. 50-69 mm Hg. It was inferred that the reversal of the functional change in CBF autoregulation reflected reversal of hypertension-induced cerebrovascular hypertrophy/hyperplasia.
The isolated occlusion of the angular gyri artery. A correlative neurological and anatomical study--case report.
Authors: Marinkovic S V , Kovacevic M S , Kostic V S
Published: June 2011

We examined a patient who had signs of a cerebral hemisphere lesion: right hemiparesis, facial weakness, right hemianopsy, acustico-mnestic dysphasia, "empty speech," acalculia, visuo-spatial agnosia and constructional apraxia, but without changes in consciousness. Taking into account clinical signs, computed tomography and carotid angiography findings, we concluded that our patient had an infarction zone in the left temporo-parieto-occipital region, as a consequence of the isolated angular gyri artery (ANG) occlusion. Some clinical signs were a direct effect of the ANG's occlusion. Namely, this artery supplies the cortical regions of great functional significance: the planum polare and temporale, the transverse temporal gyri, the superior and middle temporal gyri, the angular and supramarginal gyri, as well as the superior, middle and inferior occipital gyri. But the other symptoms and signs could be explained by the pathophysiological effect of the cerebral edema on regions supplied by the non-occluded branches of the middle cerebral artery.
The patient with transient ischemic attacks--is this the time for a new therapeutic approach?
Authors: Adams H P , Kassell N F , Mazuz H
Published: June 2011

Current and future improvements in treatment to prevent cerebral infarction among patients with transient ischemic attacks may reduce neurological morbidity but may not lead to a proportional improvement in life expectancy. Because the long-term primary cause of death in these patients is myocardial infarction, it is most likely that the most important way to prolong survival may be the vigorous investigation of their cardiac status and the treatment of their coronary artery disease, even if asymptomatic.
Decreased incidence and mortality of stroke.
Authors: Hachinski V
Published: June 2011

Dr. Whisnant argues persuasively that control of hypertension has played a major role in the decline of stroke. He offers a cohesive and logical overview on this decline and does so with data from his own vast experience and with the advantages of the Mayo Clinic system which includes a centralized population-based diagnostic index, neurological expertise and a high autopsy rate. However, neither Dr. Whisnant's arguments nor the Mayo Clinic data justify the conclusion that "treatment of hypertension is the only significant contributor to the decline of stroke."
Vertebral-basilar posterior cerebral territory stroke--delineation by proton nuclear magnetic resonance imaging.
Authors: Kistler J P , Buonanno F S , DeWitt L D , Davis K R , Brady T J , Fisher C M
Published: June 2011

We used three-dimensional proton NMR images to study ischemic infarction in the territory of the vertebral-basilar posterior cerebral circulation. The study includes sixteen cases, eight of which are presented in detail. In seven cases, the infarctions were secondary to demonstrable large artery occlusive disease -- vertebral, basilar, or posterior cerebral. In nine cases, the infarctions were secondary to what was presumably small vessel disease. In fifteen of the sixteen cases, NMR imaging could locate the infarct, inversion recovery and spin-echo pulse sequences being more sensitive than the saturation recovery pulse sequence. This efficiency rests on the high sensitivity of ischemic infarction to changes in T1 and T2 relaxation time, highlighted in the inversion recovery and spin-echo images, respectively. The additional advantages of the three-dimensional approach, and the lack of bone artifact, make NMR imaging superior to CT scanning in identifying areas of infarction in the territory of posterior cerebral circulation.
Anticoagulant-related hemorrhage in acute cerebral embolism.
Authors: Shields R W , Laureno R , Lachman T , Victor M
Published: June 2011

Five patients with nonseptic cerebral embolism of cardiac origin are reported in whom early anticoagulant therapy resulted in clinical deterioration or death from frank hemorrhage into the acute infarct. In each patient an initial CT scan excluded the presence of intracerebral hemorrhage and a second CT scan, after clinical deterioration had occurred, documented frank hemorrhage into the infarcted zone. All five patients had large infarctions in the right middle cerebral artery territory and three patients were mildly hypertensive. Four patients received heparin within 36 hours of their stroke and one was on warfarin at time of the embolism. Clinical deterioration occurred after intervals of several hours (2 cases), 5-6 days (2 cases) and 30 days (1 case). In only 2 patients was anticoagulant activity excessive at time of clinical deterioration. This report illustrates the danger of early anticoagulant therapy of acute nonseptic cerebral embolism, particularly in the setting of large infarction.
Calcium independent contraction induced by iodoacetic acid in isolated cerebral arteries.
Authors: Toda N
Published: June 2011

In helically-cut strips of cerebral arteries isolated from dogs and monkeys, the addition of 1 mM iodoacetic acid (IAA) produced contractions during an early period (5 to 10 min) and also a prolonged exposure (50 to 70 min). The early contraction was abolished by exposure to Ca++-free media containing EGTA, and significantly attenuated by treatment with procaine or dantrolene. Verapamil, lidocaine, ATP and pyruvate did not inhibit the contraction. On the other hand, the late contraction was not prevented by exposure to Ca++-free, EGTA-containing media and by treatment with procaine, dantrolene, lidocaine, ATP or pyruvate. Nitroglycerin and papaverine did not relax the IAA-contracted arteries. In dog and monkey mesenteric arteries and dog coronary, renal and femoral arteries, IAA elicited contractions after a prolonged exposure, which were not inhibited by soaking the preparations in Ca++-free, EGTA-containing media. Passive tensions developed by rapid stretch in Ca++-free media did not differ in IAA-treated and control arteries. During an early period of IAA actions, Ca++ appears to be released from intracellularly stored sites in the amount sufficient to produce significant contractions in cerebral, but not in peripheral arteries. It is concluded that the involvement of Ca++ in the late contraction induced by IAA is if any minimal, and such a contraction may be associated with functional alterations induced by the metabolic inhibitor in arterial tissues other than smooth muscle.
Early mortality following stroke: a prospective review.
Authors: Silver F L , Norris J W , Lewis A J , Hachinski V C
Published: June 2011

Analysis of early deaths after stroke is important, since some deaths may be preventable. Previous studies have relied on retrospective and often incomplete clinical data, for comparison with pathological findings. The present study is based on 1073 consecutive stroke patients admitted to an intensive care stroke unit from a well-defined population. There were 212 deaths within the first 30 days, yielding a mortality rate of 20%. Clinical, radiological, and laboratory data were collected prospectively according to a standardized protocol. Autopsies were performed on 90 of the 212 patients, and CT scanning on a further 27. Early mortality after stroke exhibits a bimodal distribution. One peak occurs during the first week, and a second during the second and third weeks. The majority of deaths in the first week are due to transtentorial herniation. Of these, deaths due to hemorrhage usually occur within the first three days, whilst deaths due to infarction peak between the third and sixth day post ictus. After the first week, deaths due to relative immobility (pneumonia, pulmonary embolism and sepsis) predominate, peaking towards the end of the second week. Cardiac deaths occur throughout the first month, and unfortunately account for many deaths in patients with small functional deficits.
A two-year longitudinal study of post-stroke mood disorders: dynamic changes in associated variables over the first six months of follow-up.
Authors: Robinson R G , Starr L B , Lipsey J R , Rao K , Price T R
Published: June 2011

We are prospectively studying a group of 103 stroke patients over the first 2 years after infarction to determine the variables which are associated with the development of depression. At both 3 and 6 months post-stroke, patients with left hemisphere infarcts showed a strong relationship between severity of depression and distance of the lesion on CT scan from the frontal pole. The strength of this association was unchanged from the immediate post-infarction period. In contrast, the correlation between degree of functional physical impairment and severity of depression steadily increased over the 6 month follow-up. The correlation between severity of depression and Mini-Mental score or between depression and social functioning score dropped between in-hospital and 3 months but then increased significantly between 3 and 6 months post-stroke. Age did not correlate with depression beyond the acute post-stroke period. Whether the increasing strength of the relationships between impairment and depression over the first 6 months post-stroke indicates that continued depression led to delayed recovery or whether continued severe impairments led to depression is not known, however, this issue will be addressed in further data evaluation from this prospective study.
The effects of a calcium antagonist (nimodipine) on basal cerebral blood flow and reactivity to various agonists.
Authors: McCalden T A , Nath R G , Thiele K
Published: June 2011

In vitro studies suggest that cerebrovascular contraction is more dependent on the influx of calcium to smooth muscle than general systemic arteries. The present study tested the in vivo effects of a calcium influx blocker (nimodipine) on cerebral blood flow and metabolism in 16 baboons. The 133xenon clearance technique was used together with careful control of EEG and blood gases. With normal blood gases intravenous nimodipine infusion (1 microgram/kg/min) produced an 18% increase in cerebral blood flow with no alteration in cerebral oxidative metabolism or blood pressure. Higher doses (above 10 micrograms/kg/min) resulted in a decreased arterial blood pressure and a return to control cerebral flow. Infusion of the dose producing maximal increase in flow, decreased the cerebral reactivity to altered PCO2 (n = 5). These results suggest that nimodipine may be a relatively selective cerebrovascular dilator.
Butanediol induced cerebral protection from ischemic-hypoxia in the instrumented Levine rat.
Authors: Lundy E F , Luyckx B A , Combs D J , Zelenock G B , D'Alecy L G
Published: June 2011

To determine if 1,3-Butanediol (BD), which protects mice from hypoxia, would extend the tolerance of rats to ischemic-hypoxia, the Levine rat (unilateral carotid ligation and conscious hypoxic exposure) was modified to record mean arterial pressure (BP), heart rate (HR), central venous pressure (CVP), spontaneous respiration and EEG. Age and weight matched, male, Sprague-Dawley rats were anesthetized under halothane (1-2%), ligated, instrumented, and recovered 2 hrs before hypoxia (4.5% oxygen). Thirty minutes prior to hypoxia, groups of rats received, BD (47 mmoles/kg i.v.; n = 7), equal volumes of saline (S) (n = 6) or no-infusion (NI) (n = 7). Since no significant difference was observed between S and NI they were combined into a single control group (C). In a parallel group administered BD, resultant beta- hydroxybutarate ( BHB ) levels increased from 0.13 +/- 0.02 to 0.84 +/- 0.03 mM and temperature declined only 1.5 degrees C. The EEG of all ischemic-hypoxic rats invariably became isoelectric before cessation of spontaneous respiration and eventual loss of BP. BD significantly (p less than 0.01, Student's t) increased ischemic-hypoxic tolerance (time to isoelectric EEG) from 875 +/- 56 for the control group to 1338 +/- 67 seconds for the BD group, without changing the interval from isoelectric EEG to loss of BP. Further, EEG activity persisted at a lower mean BP (p less than 0.01) in the BD group (44 +/- 5 mm Hg) than in the control group (66 +/- 4 mm Hg). In summary, isoelectric EEG invariably precedes ventilatory failure and cardiovascular collapse. BD increases ischemic-hypoxic tolerance in the conscious rat by extending, at a lower mean BP, the time to isoelectric EEG.
Idiopathic basilary artery occlusion in childhood (case report).
Authors: Jain S , Maheshwari M C , Tandon P N , Goulatia R K
Published: June 2011

A case of basilar artery occlusion in a 16-year-old-girl has been reported. Reports of 20 such cases occurring in children have been reviewed. In children, basilar artery occlusion is more common in males; no previous case above the age of 3 years has been reported in females. There were preceding TIA's and RIND in the vertebro-basilar territory.
Non-invasive diagnosis of mild to severe stenosis of the internal carotid artery.
Authors: Langham M E , Preziosi T J
Published: June 2011

A prospective masked study of the Langham Ocular Pressure Pulse Amplitude Procedure was made on 20 patients with arteriographically-confirmed completely patent carotid arteries (Group 1) and on 20 patients with either unilateral or bilateral stenoses of the internal carotid arteries (Group 2). The results are compared to similar studies previously reported on 20 patients with radiographically confirmed unilateral or bilateral occlusions of the internal carotid arteries (Group 3). The intraocular pressures, the pulse/intraocular pressure relations, and the ophthalmic arterial pressures were equal in pairs of eyes of Group 1 patients, and similar to those found in normal healthy subjects. The mean ophthalmic/brachial arterial pressure ratio in Group 1 patients was significantly higher than in normal subjects. In the Group 2 patients, the intraocular pressures were normal and all the measured parameters were similar in pairs of eyes, whereas, the ophthalmic/brachial arterial pressure ratios were significantly less than in the eyes of the Group 1 patients. The degree of stenoses of the internal carotid arteries (0 to 100%) as evaluated from arteriography varied inversely with the ophthalmic/brachial arterial pressure ratios (correlation coefficient 0.85). The coefficients of the sensitivity, the specificity, and the accuracy of the ophthalmic/brachial arterial pressure ratios in identifying the presence of stenotic lesions of the internal carotid artery defined by arteriography in the 120 eyes of the three groups were 89, 80, and 86% respectively. The ability of the Procedure to identify hemodynamic lesions of less than 50% is in keeping with published results of theoretical and experimental studies of the pressure gradient across stenoses in arteries with high rates of blood flow.
Failure of flunarizine to improve cerebral blood flow or neurologic recovery in a canine model of complete cerebral ischemia.
Authors: Newberg L A , Steen P A , Milde J H , Michenfelder J D
Published: June 2011

Ten minutes of cerebral ischemia was produced in 12 dogs by temporary ligation of the venae cavae and aorta. After reperfusion the dogs received the calcium entry blocker, flunarizine, 6 micrograms/kg infused over a ten minute period. Cerebral blood flow (CBF) and metabolism (CMRO2) were measured pre-ischemia and for 2 h post-ischemia in 6 dogs. At the end of the study brain biopsies were analyzed for cerebral metabolites. Neurologic recovery was evaluated for up to 48 h post-ischemia in an additional 6 dogs. The results of each study were compared to those previously obtained in untreated animals. The cerebral blood flows (when expressed as a percent of the pre-ischemic control value) of the flunarizine-treated and untreated groups were similar throughout the post-ischemic period. Following an initial hyperemia, the CBF fell to significantly less than the pre-ischemic control values, and remained approximately 26% of control during the final 90 min in both groups. The CMRO2 was also the same for both groups. Cerebral metabolites were similar although abnormal in both groups. Flunarizine produced pulmonary edema in 5 of 6 dogs studied for neurologic recovery. Four of these dogs died within 12 h and another dog demonstrated severe neurologic damage. None of the untreated dogs developed pulmonary edema, but 6 of 7 dogs evidenced severe neurologic damage or were dead at 48 h. Thus, flunarizine failed to improve either cerebral blood flow or neurologic outcome when given after complete cerebral ischemia in the dog. A cardiodepressive effect of flunarizine might have contributed to the poor neurologic outcome.(ABSTRACT TRUNCATED AT 250 WORDS)
Calcium antagonist PY 108-068: demonstration of its efficacy in various types of experimental brain ischemia.
Authors: Wiernsperger N , Gygax P , Hofmann A
Published: June 2011

The protective properties of PY 108-068 against ischemic disturbances in the brain were investigated in vitro and in vivo. The calcium antagonistic effects were demonstrated on isolated, calcium-loaded arterial rings of feline cerebral arteries. Determination of brain tissue oxygenation with pO2 microelectrodes showed that PY 108-068 improved oxygen supply in the cortex of cats subjected to epicerebral arterial occlusion. In a model of cerebral vasospasm induced by autologous blood superfusion, PY 108-068 reversed the spastic state of cortical microvessels. In a chronic stroke model (microsphere embolization in rats) PY 108-068 led to a significant reduction in mortality and in the severity of neurological symptoms, whereby the peroral efficacy of the drug could be demonstrated. The efficacy of PY 108-068 in a variety of ischemic insults makes this drug a promising aid in the treatment of cerebrovascular accidents.
Mild hypothermia and Mg++ protect against irreversible damage during CNS ischemia.
Authors: Vacanti F X , Ames A
Published: June 2011

Spinal cord ischemia was produced in rabbits by temporary occlusion of the abdominal aorta just distal to the renal arteries; and recovery, or failure to recover, was assessed by examining the rabbits for permanent loss of sensory and motor function in the hind limbs. A temperature reduction of 3 degrees C during the period of circulatory impairment caused a doubling of the duration of ischemia that could be reversibly sustained. Intravenous administration of 5 mmoles/kg of MgCl2 before the ischemia (a dose sufficient to produce neuromuscular blockade) caused a 50% increase in the tolerable duration. The combination of the 3 degrees C reduction in temperature and the elevated Mg++ increased by about 3 fold the duration of ischemia that could be sustained before irreversible damage occurred. These results may have implications for the care of patients subjected to marginal degrees of CNS ischemia.
The distribution of ischaemic damage and cerebral blood flow after unilateral carotid occlusion and hypotension in the rat.
Authors: Mendelow A D , Graham D I , McCulloch J , Mohamed A A
Published: June 2011

We have developed a model of haemodynamic cerebral ischaemia by inducing haemorrhagic hypotension (40-50 mmHg mean blood pressure) following unilateral common carotid occlusion, with external carotid ligation, in anaesthetised rats. The neuropathological pattern of ischaemic brain damage was correlated with the distribution of change in cerebral blood flow using the 14C-iodoantypyrine autoradiographic technique. Whereas hypotension alone (40-50 mmHg) resulted in neither ischaemic brain damage nor significant alterations in cerebral blood flow, the combination of this degree of hypotension with unilateral carotid occlusion produced predominantly unilateral ischaemic brain damage which correlated with regions of reduced cerebral blood flow. With this type of haemodynamically induced oligaemia, the most vulnerable areas were the lateral neocortex, the caudate nucleus, the hippocampus and the thalamus. Within the cortex, the greatest reductions in blood flow occurred in the deeper cortical layers, and this was the most frequent site of ischaemic cell change. These data support the concept of a haemodynamic mechanism in the pathogenesis of some transient cerebral ischaemic attacks in man.
Interobserver agreement for the diagnosis of transient ischemic attacks.
Authors: Kraaijeveld C L , van Gijn J , Schouten H J , Staal A
Published: June 2011

The interobserver agreement for the diagnosis of a cerebral transient ischemic attack (TIA) was investigated in a pool of eight senior and interested neurologists from the same department. They interviewed 56 patients in alternating pairs. The diagnosis was based on internationally accepted criteria. The agreement rates were corrected for chance (kappa statistics). Both neurologists agreed that 36 patients had a TIA and 12 had not, but they disagreed about 8 patients (kappa = 0.65; for perfect agreement kappa would be 1.0). The vascular territory (carotid or vertebrobasilar) was agreed upon in only 24 of the 36 patients in whom both diagnosed TIA's (kappa = 0.31). We concluded that currently the diagnosis of a TIA, made by a single neurologist, is a poorly defined entity.
Ultrastructural studies of cerebral arteries and collateral vessels in moyamoya disease.
Authors: Takebayashi S , Matsuo K , Kaneko M
Published: June 2011

Moyamoya disease was originally defined as a characteristic syndrome of recurrent headaches, occlusion of the distal internal carotid arteries and the foggy (moyamoya) clusters of collateral vessels at the base of the brain as demonstrated by cerebral angiography. The etiology is unknown and pathobiology is poorly understood. We examined the intracranial arteries in 3 patients to demonstrate characteristic changes and to obtain a better understanding of the basis mechanisms of the disease. Controls were obtained from 3 normotensive patients who died as a result of cancer. Occluded internal carotid arteries were characterized by severe thickening of the intima with a dense luminal array of smooth muscle cells, a deeper less cellular zone, pronounced tortuosity of the internal elastica and thinning of the media. Collateral vessels were arterial in structure and were affected by similar proliferative changes in the intima, thinning of the media, and contorted internal elastica. Stainable lipids were not part of the typical components. Severe contortion of the internal elastica, medial damage and intimal proliferation may result from recurrent and sustained spasticity of the cerebral arteries. The distal lenticulostriate arteries showed severe medial damage similar to what is termed as a moth-eaten change in hypertensive patients dying of massive cerebral hemorrhage.
The pilot Stroke Data Bank: definition, design, and data.
Authors: Kunitz S C , Gross C R , Heyman A , Kase C S , Mohr J P , Price T R , Wolf P A
Published: June 2011

Four university centers collaborated to contribute 1158 patients with acute episodes of cerebrovascular disease to the pilot Stroke Data Bank, initiated by NINCDS in 1978. During the pilot project a standard set of data collection forms were developed and used at each of the collaborating centers. Data on clinical course, laboratory findings, therapy and outcome were gathered prospectively throughout the patient's hospitalization and at specified follow-up intervals. Using operational definitions of stroke sub-types, consecutive cases were systematically allocated to specific categories of brain and vascular pathology. The definitions were based on clinical criteria as well as on laboratory data, including computerized tomography (CT), and angiography findings. This paper describes the pilot Stroke Data Bank and presents the distribution of cases by diagnostic and demographic categories. It represents one of the largest series of prospectively collected stroke cases studied by CT (90% of the cases) and angiography (42%). Based upon the methods and processes of this pilot study, a main phase of the Stroke Data Bank has been established to address a number of questions pertaining to stroke classification, evolution, diagnosis, and prognosis.
Cerebral blood flow measurement in cerebrovascular occlusive diseases.
Authors: Yanagihara T , Wahner H W
Published: June 2011

In order to evaluate cerebral blood flow (CBF) patterns among individual patients with increased statistical confidence, CBF measurements were carried out using the 133Xe-inhalation method and external head detectors. F1 values representing gray matter flow from 3 to 6 head detectors were averaged to form 16 different regions for each cerebral hemisphere. Normative values were obtained from 46 healthy volunteers, and data from individual regions were analyzed for absolute blood flow rates (ml/100g/min), for concordance between right and left hemispheres and as percent of mean hemispheric flow. CBF measurements were then carried out among 37 patients with cerebrovascular occlusive diseases, and results were compared with normative values. A high incidence of abnormal flows were detected among symptomatic patients with intracranial arterial stenosis or occlusion and those with extracranial internal carotid artery occlusion. By using the above method for data analysis, it was possible to delineate hypoperfused areas among these patients. Even though the 133Xe-inhalation method has inherent limitations, this is a practical and safe method for measurement of CBF which can provide reliable information useful for management of patients with cerebrovascular occlusive diseases, particularly when the results are presented with statistical confidence.
Intelligence in children with moyamoya disease: evaluation after surgical treatments with special reference to changes in cerebral blood flow.
Authors: Ishii R , Takeuchi S , Ibayashi K , Tanaka R
Published: June 2011

The effect of surgical treatment upon the intelligence of 20 children with moyamoya disease was evaluated and related to changes in cerebral blood flow (CBF). The patients were treated by various surgical revascularization procedures, mainly by encephalo-myo-synangiosis. Intelligence was tested using the Wechsler intelligence scale for children (WISC) in 19 children and the Wechsler adult intelligence scale (WAIS) in one child. Measurements of regional CBF were performed by a 133Xe inhalation method. In the preoperative state, the degree of reduction in the intelligence quotient (IQ) correlated well with the age of the patients; the older patients revealed a more marked reduction of IQ, and the patients with lower intelligence scores in general showed a tendency for more marked depression of mean CBF. Postoperatively, most of the patients showed increase in IQ, especially in performance IQ which improved significantly in 10 patients, remained unchanged in 3 and deteriorated in 2. Mean CBF increased by an average of 11.4%, and postoperative changes in mean CBF correlated well with the changes in IQ in most patients. This may show that the postoperative increase in CBF is quite possibly responsible for the changes in IQ.
Agitated confusional states in patients with right hemisphere infarctions.
Authors: Schmidley J W , Messing R O
Published: June 2011

Patients with infarctions in the territory of the right middle cerebral artery (RMCA) sometimes present with an agitated confusional state. We reviewed clinical data on 46 patients with RMCA infarcts and compared neurologic findings in patients with and without agitated confusion. Neither of the two patients presenting with agitated confusion showed obvious localizing neurologic signs; subtle motor, visual field and sensory deficits referable to the infarcted regions were present, but difficult to elicit because of the mental state. In contrast, all but one of the patients without agitated confusion had prominent motor and sensory signs. Infarction of the RMCA territory may cause agitated confusion in patients without prominent localizing signs; the initial neurologic findings may suggest a metabolic encephalopathy. However, the possibility of a cerebrovascular cause should not be dismissed in confused and agitated patients who have no definite lateralizing signs.
Use of short-lived 18F and long-lived 14C in double tracer autoradiography for simultaneous measurement of LCBF and LCGU.
Authors: Sako K , Kato A , Diksic M , Yamamoto L Y
Published: June 2011

We have developed a quantitative autoradiographic technique for the simultaneous measurement of local cerebral blood flow (LCBF) and local cerebral glucose utilization (LCGU) using a combination of 14C-long-lived and 18F-short-lived radionuclides as labels. To obtain the LCGU image, a 50-fold greater radioactivity of 18F than of 14C was administered and the first exposure was done for 2 hours. Three days later, when most of the 18F had decayed, a second exposure was done for 5 to 6 days to obtain the LCBF image. 18F standards were prepared in each experiment. The technique provides, for the first time, the local glucose flow ratio (LGFR). LGFR, obtained by dividing the LCGU by the LCBF image, was expressed as percent mumol/ml (multiplied by 100). Measurement of these three values in the same animal is expected to prove useful in the investigation of the pathophysiology of the brain. The advantages of this method are that cross contamination is less than 4%, chemical or physical manipulation of the slices is unnecessary, and final results can be obtained within a week.
Elimination of subjective bruit with compression of temporal artery: new physical sign indicative of internal carotid artery occlusion.
Authors: Chang G Y
Published: June 2011

A patient is presented with a right central retinal artery occlusion and subjective bruit over right ear. Digital compression of the right temporal artery eliminated the bruit and release reproduced the bruit. Carotid arteriogram showed bilateral internal carotid occlusion with a prominent right temporal artery. This sign reflects compensatory hyper-perfusion of the external carotid artery due to occlusion of ipsilateral internal carotid artery.
Massive intracerebral hemorrhage complicating cardiac catheterization with ergonovine administration.
Authors: Piatt J H
Published: June 2011

Massive intracerebral hemorrhage is reported as a complication of cardiac catheterization with ergonovine administration. Possible mechanisms relating stroke to cardiac catheterization are reviewed. Patients who suffer neurologic deterioration after this procedure require prompt evaluation including computed tomography.
Moderate homocysteinemia--a possible risk factor for arteriosclerotic cerebrovascular disease.
Authors: Brattstrom L E , Hardebo J E , Hultberg B L
Published: June 2011

Highly elevated concentrations of homocysteine measured as homocysteine or cysteine-homocysteine mixed disulfide (MDS) are found in plasma and urine in subjects with inherited abnormalities of the methionine metabolism. These subjects have a high incidence of arteriosclerotic vascular complications during childhood. Homocysteine causes endothelial cell injury and cell detachment that initiates the development of arteriosclerosis. The present study demonstrates a significantly elevated mean plasma MDS concentration in 19 patients with arteriosclerotic cerebrovascular disease compared to 17 controls. Our findings suggest that moderate homocysteinemia might be a risk factor for arteriosclerotic cerebrovascular disease.
Inhibition by ketanserin of serotonin induced cerebral arteriolar constriction.
Authors: Thompson J A , Wei E P , Kontos H A
Published: June 2011

We studied the effects of serotonin on pial arterioles in anesthetized cats equipped with acutely implanted cranial window for the observation of the pial microcirculation. Serotonin topically applied caused cerebral arteriolar constriction. Ketanserin, a specific 5-HT2 inhibitor, completely blocked the vascular response of serotonin. Aggregated platelet supernatant was topically applied and caused generalized cerebral arteriolar constriction that could be blocked with ketanserin. We conclude that serotonin causes generalized cerebral arteriolar constriction that is due to the stimulation of 5-HT2 receptor. Aggregating platelets release serotonin, which mediates the vasoconstrictive action of the supernatant solution.
Comparison of the effect of naloxone on cerebral versus mesenteric arterial smooth muscle in feline and primate species.
Authors: Sasaki T , Kassell N F , Turner D M , Coester H C
Published: June 2011

This study was conducted in order to investigate naloxone's in vitro action on both epinephrine-induced constriction of mesenteric artery and norephinephrine-induced constriction of cerebral arteries in different species (cat and monkey). Naloxone (3 X 10(-5)M) augmented the epinephrine-induced constriction of both feline and monkey mesenteric artery at epinephrine concentrations of 10(-7) to 10(-5) M. Naloxone (3 X 10(-5)M) suppressed the constriction of feline basilar artery induced by high concentrations (10(-4), 10(-3) and 3 X 10(-3)M) of norepinephrine, while it failed to alter the constriction induced by lower concentrations (10(-7) to 10(-5)M) of norepinephrine. The constrictor response of monkey basilar artery to norepinephrine (10(-8) to 10(-5) M) was not altered by treatment with naloxone (3 X 10(-6) and 3 X 10(-5)M). Such varying effects of naloxone in different tissues and species may have to be taken into account when evaluating the cerebral blood flow changes following naloxone administration.
Verapamil: failure of metabolic amelioration following global forebrain ischemia in the rat.
Authors: Berger J R , Busto R , Ginsberg M D
Published: June 2011

The potential efficacy of the calcium channel blocker verapamil in modifying ischemic brain injury was evaluated in anesthetized rats subjected to 60 or 90 min of diffuse forebrain ischemia produced by bilateral occlusion of the carotid and vertebral arteries. Treated animals received verapamil, 2 mg/kg intravenously, prior to ischemia. Four hours of postischemic recirculation was permitted by reversing the carotid occlusions. Intermittent high-voltage slow-wave activity was noted on electroencephalograms shortly after verapamil infusion, prior to ischemia. The ischemic insult induced an isoelectric EEG, which tended to persist during recirculation in both treated and untreated animals. Similarly, verapamil pretreatment failed to influence brain water content or cerebral energy metabolites (phosphocreatine, ATP, ADP, AMP) or cerebral energy charge when assayed after four hours of recirculation. Thus, verapamil failed to confer a protective effect on brain electrical activity, water content, or energy metabolites following ischemia in this model.