bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrocardiographic changes and myocardial damage in patients with acute cerebrovascular accidents.
Authors: Dimant J , Grob D
Published: June 2011

In 100 consecutive patients with acute cerebrovascular accident, due to cerebral thrombosis in 72, cerebral hemorrhage in 12, embolus in 6, and subarachnoid hemorrhage in 10, there were 90 who had electrocardiographic abnormalities during the first three days after admission, compared to 50% in a control group. The patients with cerebrovascular accident had a 7- to 10-fold higher incidence of ST segment depression, prolonged Q-Tc interval and atrial fibrillation, and a 2- to 4-fold higher incidence of T wave inversion, conduction defects, premature ventricular beats and left ventricular hypetrophy. Patients who died had a 2-, 3- and 5-fold higher incidence of electrocardiographic evidence of recent myocardial infarction, atrial fibrillation and conduction defects than those who survived, but these changes occurred in only 5, 21 and 14% of all patients, and other electrocardiographic changes could not be correlated with mortality. During the first three days after admission 29 patients had elevation of serum enzymes which may be derived from cardiac muscle, particularly CPK, which was increased 6-fold, compared to 2-fold increases in HBDH, GOT, and LDH. Only 5 of these patients had electrocardiographic evidence of recent myocardial infarction. Patients with elevated serum CPK had a 2-fold higher incidence of ST segment depression, T wave inversion, conduction defects and atrial fibrillation than those with normal CPK, and a mortality of 66%, compared to 30%. Of 41 patients who died, 49% had elevated serum CPK, compared to 15% of 59 patients who survived. These differences were significant (P less than 0.01). Serum CPK was more frequently helpful than the electrocardiogram in evaluating the extent of cardiac damage and in predicting mortality. Patients with acute cerebrovascular accident should have repeated evaluation of serum CPK and the ECG, and be monitored for arrhythmias.
Developmental course of hypertension and regional cerebral blood flow in stroke-prone spontaneously hypertensive rats.
Authors: Yamori Y , Horie R
Published: June 2011

Regional cerebral blood flow (rCBF) was repeatedly measured by the hydrogen clearance method in the frontal cortex of stroke-prone spontaneously hypertensive rats (SHRSP) at the age of 50 days and thereafter. When SHRSP rats developed severe hypertension (over 200 mg Hg at the age of 60 days) rCBF began to decrease abruptly in the frontal cortex--one of the three predilection sites of stroke in these rats. In contrast, such a reduction in rCBF was not noted in either stroke-resistant spontaneously hypertensive rats (SHRSR) which developed moderate hypertension (under 200 mg Hg), or in Wistar-Kyoto rats (WK) with normal blood pressure (under 15 mm Hg). A similar marked reduction of rCBF with severe hypertension (over 200 mm Hg) was also detected in apoplectic gene-free renal infarction hypertensive rats (RHR) experimentally produced from age-matched WK animals. Blood samples were obtained through an implanted femoral artery canula without disturbing the nonanesthetized SHRSP, SHRSR and WK rats. Arterial blood gas analysis (PaCO2, PaO2 and pH) showed no significant differences at the age of 5 months in any of these rats. Chemical cerbrovascular reactivity, that is, an increase in rCBF in response to CO2 inhalation, showed no significant difference among SHRSP rats from the age of 50 days to 5 months. However, it markedly decreased in SHRSP rats at the age of 9 months and thereafter (the average age of male SHRSP rats which develop stroke is 9 months). The present study showed stroke did not occur in antihypertensive agent-treated SHRSP rats. In these SHRSP rats rCBF did not decrease as long as blood pressure was well-controlled.
Cerebral arterial smooth muscle contraction by thromboxane A2.
Authors: Ellis E F , Nies A S , Oates J A
Published: June 2011

The contractile effects of thromboxane A2 (TxA2), a labile arachidonic acid metabolite, were studied in arterial smooth muscle strips. TxA2 was generated upon the addition of 255 nM prostaglandin cyclic endoperoxide H2 to human platelet particles in the muscle bath. Using the isometric contaction produced by 40 mM K+ in isotonic saline as the reference contraction, bovine middle cerebral artery strips contracted to 153 +/- 14% of the reference response while bovine coronary and porcine coronary, renal and common carotid strips contracted to 47 +/- 3, 26 +/- 5, 43 +/- 2 and 2 +/- 1% of reference, respectively. The cerebral artery response to the TxA2 generating system was as great as the maximum response to prostaglandin F2alpha and two times the maximum response to 5-hydroxytryptamine. Because TxA2 is formed by brain tissue and released from aggregating platelets, it may be important in the pathogenesis of spasm associated with injured brain tissue or pathologic changes leading to platelet aggregation.
Evoked potential changes during brain retraction in dogs.
Authors: Bennett M H , Albin M S , Bunegin L , Dujovny M , Hellstrom H , Jannetta P J
Published: June 2011

Brain retraction and induced hypotension are surgical adjuncts capable of compromising cerebral blood flow. To evaluate their effects upon brain function, cortical evoked potentials, neurological status and cortical histological changes were determined as a function of graded levels of brain retractor and systemic perfusion pressure in the dog. Somatosensory evoked potentials recorded from the site of application of brain retraction showed a decrement as a function of both the amount of retraction pressure and the systemic perfusion pressure. An electrode distant from the retractor site showed similar, though reduced and more variable changes in amplitude. For higher levels of brain retractor pressure, induced hypotension to 50 mm Hg systemic perfusion pressure produced greater reductions in evoked potentials than in normotensive subjects. It was demonstrated that a reduction of 50% of the evoked potential amplitude after sixty minutes brain retraction signaled, with high probability, the occurrence of postoperative sensory and/or motor deficits and cortical histopathology. It was concluded that cortical evoked potentials represent a reliable indicator of the functional effects produced by applied cortical retraction pressure at several levels of systemic perfusion pressure. It was suggested that the recording of evoked potentials would prove most useful during neurosurgical procedures employing induced hypotension and brain retraction.
Three-area epidemiological study of geographic differences in stroke mortality. I. Background and methods.
Authors: Nefzger M D , Kuller L H , Lilienfeld A M , Diamond E L , Miller G D , Stolley P D , Tonascia S
Published: June 2011

An epidemiological study was conducted to determine the geographical variations in stroke mortality among three U.S. areas. They were Savannah, Georgia (high stroke rates), Hagerstown, Maryland (intermediate stroke rates) and Pueblo, Colorado (low stroke rates). In each area samples were drawn of the population in the 35--54 age group. The subjects were interviewed and examined to obtain the information required on medical conditions and/or living habits which would characterize each area. A brief medical and family history, as well as demographic and personal data, were obtained by interview. The medical examination included blood pressure, ECG, blood and urine chemistry, height and weight. In all three cities the response rate in the final sample selected was 90% (2,375 individuals) interviewed and 74% (1.939 individuals) examined.
Three-area epidemiological study of geographic differences in stroke mortality. II. Results.
Authors: Stolley P D , Kuller L H , Nefzger M D , Tonascia S , Lilienfeld A M , Miller G D , Diamond E L
Published: June 2011

An epidemiological study was conducted of geographic differences in stroke mortality between the following areas within the United States; Savannah, Georgia (high stroke rates), Hagerstown, Maryland (intermediate stroke rates) and Pueblo, Colorado (low stroke rates). Population samples 35--54 years of age of the three cities were drawn for interview and examination to determine medical conditions and living habits of these populations. The population samples were compared with emphasis on possible risk factors for stroke: serum cholesterol and glucose tolerance test determinations, weight and height measurements, blood pressure and cigarette smoking. The gradient of increasing prevalence of stroke-related risk factors from low to intermediate to high for the three cities was present for blood pressure in black females and white males and for glucose tolerance tests in whites and nonwhites. No other consistent pattern of increasing prevalence of risk factors for stroke was evident.
Stroke and mortality rate in carotid endarterectomy: 228 consecutive operations.
Authors: Easton J D , Sherman D G
Published: June 2011

A retrospective study of 228 consecutive carotid endarterectomies was conducted to determine the operative stroke and mortality rate in two 600-bed community hospitals. The combined stroke-mortality rate for the series was 21.1% (48 of 228). Eleven endarterectomies were performed for asymptomatic bruits and the combined stroke-mortality rate was 18.2% (2 of 11). Fifty-seven endarterectomies were performed for transient ischemic attach(s) in the symptomatic carotid artery distribution and the combined stroke-mortality rate was 21.1% (12 of 57). Seventy-one endarterectomies were performed following a mild-moderate stroke in the symptomatic carotid artery distribution and the combined stroke-mortality rate was 21.1% (15 of 71). Twelve endarterectomies were performed following a severe stroke in the symptomatic carotid artery distribution and the combined stroke-mortality rate was 41.7% (5 of 12). There was no trend toward more or less operation strokes or deaths from 1970 to 1976. The similarity of results among the eleven board-certified neurological and vascular surgeons who performed the 228 endarterectomies suggests that the operative stroke and mortality rates for carotid endarterectomy reported here are likely to be representative of those in many other community hospitals in this country in the 1970s.
Diagnostic reliability of the percutaneous ultrasonic Doppler technique for vertebral arterial occlusive diseases.
Authors: Kaneda H , Irino T , Minami T , Taneda M
Published: June 2011

There is little data on the diagnostic reliability of the ultrasonic Doppler technique for vertebral arterial occlusive lesions. Percutaneous vertebral Doppler examination and the vertebral angiograms were compared to determine the diagnostic reliability of this technique in 64 vertebral arteries of 53 patients with cerebrovascular disease. The percutaneous vertebral Doppler findings were quantitatively analyzed using a sound spectrograph and were classified into three types: no flow signal type, poor flow type and normal flow type. In nine patients with the no flow type the angiograms revealed vertebral occlusion or a missing vertebral artery in six, giving a diagnostic reliability of 67%. In 17 patients with poor flow type the angiograms revealed vertebral occlusion or a missing vertebral artery in five, terminal narrowing of the artery in nine, and hypoplasia in two giving a diagnostic reliability of 94%. For all vertebral arteries examined with this technique, including normal ones, the diagnostic reliability was 92% (59/64). Percutaneous vertebral Doppler examination has clinical usefulness as a screening test for occlusive vertebral arterial diseases.
Effects of antihypertensive drugs on blood velocity in rhesus monkeys.
Authors: Spence J D , Pesout A B , Melmon K L
Published: June 2011

Increasing evidence suggests that higher blood velocity, by causing turbulence and high shear rates at the endothelial surfaces of arteries, may be important in the pathogenesis of atherosclerosis. In order to measure the effects of antihypertensive agents on blood velocity, an improved method has been developed for analysis of Doppler ultrasound velocity recordings. The audio signal from a Doppler velocity meter is subjected to spectral analysis; the sonagraph thus obtained is digitized with the use of a magnetic table on-line with a calculator. Four monkeys were maintained at a hypertensive baseline for six weeks by infusion of angiotensin and isoproterenol. The effects on blood velocity of 72-hour infusions of propranolol, clonidine, hydralazine, and methyldopa were studied. In doses that reduced diastolic pressure by 13--28%, propranolol decreased mean blood velocity (mv) by 17%, clonidine decreased mv by 14%, while methyldopa increased mv 12%, and hydralazine increased mv by 52% (p less than .00001). Antihypertensive drugs appear to have different effects on blood velocity; these differences may influence choice of antihypertensive drugs for the prevention of arterial disease.
Diagnostic significance of CSF spectrophotometry and computer tomography in cerebrovascular disease. A comparative study in 231 cases.
Authors: Söderström C E
Published: June 2011

Two hundred and thirty-one patients with cerebrovascular disease were examined by spectrophotometry of the cerebrospinal fluid (CSF) and by computer tomography. Many were followed by repeated examinations. Specific diagnoses --- bleeding as opposed to non-hemorrhagic or hemorrhagic infactions --- were indicated in 97% by spectrophotometry and in 65% by CT scan in 201 of the 231 cases (excluding 25 patients with transient ischemic attacks and five patients with cerebral tumors with cerebrovascular onset). Comparison between the two methods revealed agreement in most cases, with disagreement in only a few. The specific diagnosis was generally established on only one examination by both methods: repeated examinations were necessary in only a few cases. The results indicated that a combination of the two complementary methods established the diagnosis in almost all cerebrovascular disorders. This was particularly evident if the examinations were performed 24 hours to 21 days after onset of disease.
Concomitants of atherosclerotic carotid artery stenosis.
Authors: Duncan G W , Lees R S , Ojemann R G , David S S
Published: June 2011

To identify metabolic and other concomitants of a single important type of atherosclerotic cerebrovascular disease, 75 patients with angiographically and surgically proven internal carotid stenosis were compared with age and sex matched control subjects with respect to plasma cholesterol, triglycerides and glucose. They were also compared for blood pressure, cigarette smoking, evidence of ischemic heart disease, peripheral vascular disease and for a family history of these diseases. Patients with carotid stenosis had higher systolic and diastolic blood pressures and higher plasma cholesterol and triglyceride concentrations than the control groups. They had, as well, a far greater likelihood of being cigarette smokers and a greater likelihood of having diabetes mellitus and previous evidence of coronary and peripheral vascular disease. Patients with carotid stenosis were far more likely to have 2 or more of these common concomitants of atherosclerosis than were the control subjects. The data suggest that the precursors of carotid stenosis are similar to those of coronary atherosclerosis and raise the hope that modification of these factors may decrease the incidence of this highly prevalent form of cerebrovascular disease.
Effect of topically applied serotonin on local cerebral blood flow.
Authors: Martins A N , Doyle T F , Wright S
Published: June 2011

It has been hypothesized that acute lesions of the brain enlarge through an autodestructive process. Serotonin (5HT), a potent cerebral vasoconstrictor, is believed by some to mediate the process by reducing cerebral blood flow (CBF) in tissue surrounding the lesion. The hypothesis was tested in cynomologus monkeys anesthetized with ketamine and nitrous oxide. Craniectomies, 7 mm in diameter, were performed in each parietal area. The dura was opened and polarographical electrodes of thin platinum wire were inserted into the parietal lobe cortex of each hemisphere. Mock cerebrospinal fluid (CSF) was irrigated continously onto the brain surrounding the electrodes, from which local CBF was determined repeatedly by the hydrogen-clearance technique. After baseline CBF was established, solutions of 5HT in mock CSF (in concentrations of 5 X 10(-7) M, 5 X 10(-5) M, and 5 X 10(-3) M) were irrigated onto one hemisphere while the opposite hemisphere served as control. 5HT failed to change CBF. Although 5HT is a potent vasoconstrictor, under physiologic conditions it apparently is unable to effect hemodynamically significant constriction of the peripheral cerebral vasculature of the anesthetized monkey brain.
Analysis of the effect of bilateral sympathetic stimulation of cerebral and cephalic blood flow in the dog.
Authors: Barber B J , Martin J S , Rapela C E
Published: June 2011

Unilateral stimulation of the cervical sympathetic in dogs had no effect on cerebral blood flow (CBF) measured by the venous outflow technique. Since this technique measured CBF from both cerebral hemispheres, small changes induced by unilateral stimulation could have been masked by a large constant CBF measured from the contralteral hemisphere. To test this possibility the effect of simultaneous bilateral sympathetic stimulation was studied when the dog was breathing either normal air or a gas mixture of 10%CO2. During normocapnia, no changes in CBF occurred; during hypercapnia CBF increased 19% following passively the increase in blood pressure. These data indicate that bilateral stimulation of extracranial sympathetic nerves does not exert a significant effect on CBF. We show mathematically and experimentally that unoccluded anastomses will cause CBF to appear to decrease in response to sympathetic stimulation. This may explain why others have observed changes in CBF during sympathetic stimulation.
Cerebral infarction in young adults.
Authors: Grindal A B , Cohen R J , Saul R F , Taylor J R
Published: June 2011

The etiologic and prognostic features which characterize cerebrovascular disease in the later decades of life are not applicable in younger patients. The records of 58 patients who had suffered cerebral infarction between the ages of 15 and 40 were reviewed in order to study these features. Fifty-five percent of the patients were found to have had an identifiable etiology for their cerebral infarction, with nearly half of these suffering from embolic infarction of cardiac origin. In 45% no clear etiology could be established but hypertension was prevalent in those patients between 31 and 40 years of age. Follow up data were obtained on 68% of the hospital survivors; nearly 3/4 of them had completely recovered or had improved.
Modification of acute focal ischemia by treatment with mannitol.
Authors: Little J R
Published: June 2011

A simple implanted device was used to occlude acutely the left middle cerebral artery (MCA) of 16 conscious cats. Eight received no treatment and 8 were given intravenous mannitol (1.2 gm/kg) at the time of occlusion. The initial neurological findings in both groups were similar, that is, agitation, forced circling, and right hemiparesis. The treated cats remained alert but the untreated cats became lethargic and drowsy. Perfusion with a mixture of colloidal carbon and buffered paraformaldehyde was carried out from 30 minutes to 6 hours following MCA occlusion. Results of morphological examination of brains from the treated and untreated groups suggested that mannitol had a protective effect upon cerebral tissue during the primary phase of acute focal ischemia. Light microscopic analysis of neuronal alterations demonstrated considerable preservation of neurons in brains of treated cats. Beneficial effect of mannitol was attributed partly to prevention of capillary narrowing and suppression of ischemic cerebral edema.
Dilated episcleral arteries--a significant physical finding in assessment of patients with cerebrovascular insufficiency.
Authors: Countee R W , Gnanadev A , Chavis P
Published: June 2011

Dilated episcleral vessels associated with ipsilateral internal carotid artery occlusions have been previously reported though not widely appreciated. These ocular changes have been presumed to be manifestations of ocular ischemia. The authors have recently encountered this sign in seven patients and in none was there evidence of ocular ischemia. In addition to an ipsilateral internal carotid artery occlusion, arteriograms demonstrated that the major source of blood supply to the homolateral cerebral hemisphere was by retrograde flow through markedly enlarged ophthalmic arteries filled in retrograde fashion from dilated external carotid collateral channels in the orbit. This association of dilated episcleral arteries as a sign of increased orbital blood flow and the major source of collateral blood supply to the homolateral cerebral hemisphere has not been previously reported. We reemphasize the importance of a careful examination of the episcleral vessels in patients suspected of having internal carotid artery occlusions.
Cerebrovascular disease in sickle cell anemia: a clinical, pathological and radiological correlation.
Authors: Merkel K H , Ginsberg P L , Parker J C , Post M J
Published: June 2011

An opportunity to study cerebrovascular changes in sickle cell anemia (SCA) presented itself when a black child with this disorder died of bihemispheric strokes. Angiography demonstrated severe occlusive vascular disease involving primarily the circle of Willis and major bifurcations of both internal carotid arteries. Collateral circulation to the distal branches of the internal carotid arteries occurred through transdural anastomoses from the external carotid system and via the leptomeningeal route. Perfusion of the basal ganglia was accomplished by vessels arising from the proximal internal carotid arteries. These changes resembled those of Moyamoya disease. Autopsy showed old and recent cerebral infarcts. Two vascular processes were responsible for the arterial occlusions: (1) exuberant intimal hyperplasia, and (2) old and recent thrombi with partial recanalization. The former has been described only once before in SCA. Small vessels in the basal ganglia were exceptionally numerous and dilated. We conclude that intimal hyperplasia within large cerebral arteries may be responsible for infarction and small vessel prliferation in basal ganglia in patients with SCA.
Prolonged contraction of isolated human and canine cerebral arteries induced by uridine 5'-triphosphate.
Authors: Urquilla P R
Published: June 2011

Uridine 5'-triphosphate (UTP) induced long-lasting contractions of isolated human brain arteries; contractions without decrement were observed for periods of up to 20-24 hours at which time the tissues were relaxed in a dose-dependent manner by theophylline. In some vessels, rhythmic oscillations accompanied the prolonged elevation in tension. In canine middle cerebral arteries, UTP produced dose related contractions within the dose range of 1.7 X 10(-6) to 1.7 X 10(-4) M; these responses were unaffected by methysergide 2.8 X 10(-7) M, phenoxybenzamine 2.9 X 10(-5) M or indomethacin 9.8 X 10(-6) M, suggesting that the UTP mechanism of action is probably independent of tryptaminergic or alpha adrenergic receptor activation, or of prostaglandin biosynthesis. The ability of UTP to produce prolonged contraction of cerebral vessels, thus, provides an in vitro preparation in which it is possible to study some of the basic mechanisms that are associated with cerebral vasospasm.
Experimental cerebral infarction. Part 1: Production of thalamic infarction in dogs.
Authors: Yoshimoto T , Sakamoto T , Suzuki J
Published: June 2011

Difficulties in achieving focal temporary cerebral ischemia in experimental animals have delayed study of the prevention and treatment of cerebral infarction. We have succeeded in producing focal cerebral infarction by temporary occlusion of brain arteries. Infarction confined to the anterior portion of the thalamus was obtained by simultaneous occlusion of the 4 cerebral arteries: internal carotid, anterior cerebral, middle cerebral and posterior communicating arteries for 60-120 minutes. This experimental model in dogs is unique, since thalamic infarction can be produced with high frequency, and the dogs can be kept alive and managed for sufficient periods after temporary artery clipping. With this model it is possible to investigate cerebral infarction not only from the pathophysiological viewpoint, but also from the viewpoint of prevention and treatment of cerebral infarction in man.
Experimental cerebral infarction. Part 3: Protective effect of mannitol in thalamic infarction in dogs.
Authors: Yoshimoto T , Sakamoto T , Watanabe T , Tanaka S , Suzuki J
Published: June 2011

Whether or not mannitol can prevent infarctions in ischemic brain tissues was investigated utilizing the thalamic infarction model in dogs. Twenty dogs were divided into equal control and mannitol treatment groups. Temporary 4 vessel clipping for 60 minutes was adopted as the standard procedure for both groups. The only difference between the groups was the administration of 2 g/kg of mannitol before the arterial occlusion. In the controls, 6 of 10 dogs showed infarctions verified by histological changes at the seventh post-ischemic day. In the mannitol group only 1 dog in 10 showed infarction. The difference is statistically significant.
Rat brain osmolality during barbiturate anesthesia and global brain ischemia.
Authors: Bandaranayake N M , Nemoto E M , Stezoski S W
Published: June 2011

Ischemic brain damage can be partially ameliorated by barbiturate therapy applied postinsult. Catabolism-induced brain hyperosmolality during ischemia may contribute to the development of brain edema after restoration of circulation. To determine changes in brain osmolality during ischemia and the effect of barbiturate anesthetics in altering its course, we measured whole and regional (cerebral cortex, diencephalon-midbrain, and cerebellum) brain osmolality for up to 2 hours after decapitation ischemia in unanesthetized and pentobarbital anesthetized rats. Normal (nonischemic) brain osmolality in pentobarbital anesthetized rats was 319 +/- 2 mOsm/1 (mean +/- SEM) and higher than in unanesthetized rats (307 +/- 6 mOsm/1). The rate of increase in whole brain osmolality was 60% slower in pentobarbital anesthetized rats in the first 60 minutes of ischemia and regional brain osmolality increased by a maximum of 32 mOsm/1 compared to 45 mOsm/1 in unanesthetized rats. The potential for edema based on percent change in brain osmolality as well as the rapidity of the change was greater in unanesthetized rats. The significance of the increase in brain osmolality with barbiturate anesthesia and its attenuation of the rate and magnitude of increase during ischemia is discussed.
Disappearing carotid defects.
Authors: Yarnell P , Earnest M , Kelly G , Sanders B
Published: June 2011

Large intraluminal cervical carotid artery filling defects consistent with mural thrombi were angiographically demonstrated during acute hemispheric neurologic episodes. These thrombi disappeared benignly as shown by serial angiography in 2 patients treated with intravenous heparin and spontaneously in 1 patient treated surgically. Thus, partially obstructing cervical carotid artery thrombi may lyse either with the use of anticoagulant therapy or else spontaneously. The etiology of the thrombi may partly be related to underlying atheromatous disease.
Controlled trial of aspirin in cerebral ischemia. Part II: surgical group.
Authors: Fields W S , Lemak N A , Frankowski R F , Hardy R J
Published: June 2011

Patients (125) who had carotid transient ischemic attacks (TIAs) and one or more accessible carotid lesions visualized angiographically had reconstructive operations of the carotid artery and were then randomly assigned to aspirin or placebo treatment. The were followed to determine the incidence of subsecquent TIAs, death, cerebral infarction, or retinal infarction. Life table analysis (for 24 months follow up) that eliminated deaths which were not stroke-related revealed a significant difference in favor of aspirin. Because of the small number of patients and the short period of follow up, these results should be interpreted only as consistent with those reported in the initial publication but not conclusive of an aspirin effect in preventing cerebral infarction.
Effects of phenobarbital in cerebral ischemia. Part I: cerebral energy metabolism during pronounced incomplete ischemia.
Authors: Nordström C H , Siesjö B K
Published: June 2011

Changes in cerebral cortex concentrations of high-energy phosphates, glycolytic metabolites, citric acid cycle intermediates, associated amino acids, and ammonia, were studied after 5, 15 and 30 min of incomplete ischemia in rats anesthetized with 70% N2O or 150 mg.kg-1 of phenobartibal. Previous results have shown that with this type of ischemia (bilateral carotid artery occlusion combined with reduction in blood pressure to 50 mm Hg) cortical blood flow is reduced to below 10% of nitrous oxide values, whether animals are anesthetized with 70% N2O or 150 mg.kg-1 of phenobarbital. In animals under 70% N2O, changes in tissue concentrations of phosphocreatine, ATP, ADP and AMP were similar to those previously obtained in complete ischemia. However, some glucose remained in the tissue, and the lactate concentrations gradually rose to reach excessive values. Changes occuring in glycolytic and citric acid cycle intermediates were similar to those seen in complete ischemia but, after 30 min, there was some reduction in the pool size of amino acids. In those animals given phenobarbital and which lost all EEG activity during ischemia, changes in cerebral metabolites were virtually identical to those observed in nitrous oxide-anesthetized animals. However, some animals exposed to 5 or 15 min of ischemia had some remaining EEG activity. In these, cerebral energy state was significantly less deranged, and levels of glycogen, glucose and pyruvate were higher.
Relationship between ophthalmic artery blood flow and recanalization of occluded carotid artery. Ultrasonic Doppler study.
Authors: Kaneda H , Irino T , Arita N , Minami T , Taneda M , Shiraishi J
Published: June 2011

Ophthalmic artery blood flow in 5 patients with internal carotid artery occlusion of sudden onset was monitored by an ultrasonic Doppler flowmeter to investigate the possible relationship to spontaneous recanalization of the occluded artery. The occluded internal carotid arteries of 2 patients were confirmed angiographically to recanalize and the reversed flow of their ophthalmic arteries changed to physiological flow after the recanalization. The ophthalmic artery blood flow remained reversed in 2 patients whose occluded internal carotid arteries did not recanalize on the follow up angiograms. In the other patient, whose ophthalmic artery blood flow was not detected by the ultrasonic Doppler flowmeter in the acute stage, physiological flow through the ophthalmic artery was detected later. The occluded internal carotid artery did not recanalize and this physiological ophthalmic artery blood flow was filled through the circle of Willis.
Comparative angiographic and histological evaluations of intracranial atherosclerosis in hypertensive and normotensive subjects.
Authors: Araki G , Mihara H , Mizukami M , Kin H , Nishijima M , Yoshida Y
Published: June 2011

Cerebral atherosclerosis without luminal narrowing has been found macroscopically and by angiographic examinations in some patients with cerebral hemorrhage. In order to clarify the histology of non-stenotic atherosclerosis of the cerebral vessels, we examined cleared specimens and serial sections of the main trunks of the cerebral arteries. The middle cerebral artery was selected in 20 cases of cerebral hemorrhage and 7 cases of cerebral infarction. Non-stenotic atherosclerosis was found frequently in cases of cerebral hemorrhage, while most patients with cerebral infarction showed stenotic cerebral atherosclerosis. We counted the numbers of medial smooth muscle cells in 10 autopsied cases of cerebral hemorrhage and 6 of cerebral infraction. The mean numbers of smooth muscle cells per unit area in the patient with cerebral hemorrhage were less than those in cerebral infraction. In cerebral hemorrhage, the main trunks of the cerebral arteries were dilated, probably as a result of the damage to medial muscle cells and higher blood pressure during the course of intimal thickening. It is considered that arterial hypertension spreads to the peripheral, small arteries through the main trunks without luminal narrowing of the cerebral vessels.
Comparative responses of the carotid and vertebral arterial systems of rhesus monkeys to betahistine.
Authors: Tomita M , Gotoh F , Sato T , Amano T , Tanahashi N , Tanaka K , Yamamoto M
Published: June 2011

A newly developed photoelectric method was used in 5 rhesus monkeys to measure the mean transit time of blood through the carotid and vertebral arteries, together with measurement of the blood flow through the tissues of the fronto-parietal area supplied by the carotid artery and of the cerebellar tonsil supplied by the vertebral artery. Following intravenous administration of betahistine mesylate, a histamine analog, the mean transit times of blood through the 2 arteries were equally shortened by 10%, despite a 20% decrease in the mean arterial blood pressure (P less than 0.05). The cerebral tissue and cerebellar tissue blood flow was increased by betahistine, from 70.4 to 81.4 ml/100g/min and from 73.2 to 84.0 ml/100g/min, respectively. Since histamine has been reported to produce a decrease in cardiac output, the increase in cerebral blood flow confirmed that betahistine is a selective cerebral vasodilating agent. However, by comparing the hemodynamic data for the two cerebral arterial systems, it can be concluded that the responses of the carotid and vertebral arterial systems to the vasodilating action of betahistine were essentially the same in extent.
Alterations of cyclic AMP in cerebral ischemia.
Authors: Flamm E S , Schiffer J , Viau A T , Naftchi N E
Published: June 2011

Cyclic AMP levels were measured in brains of 21 cats after occlusion of a middle cerebral artery by a transorbital approach. Brain samples for determination of cAMP by a protein binding radioassay were obtained from the ischemic and contralateral temporal lobes before sacrifice, 1, 3, and 24 hours after occlusion of the right middle cerebral artery. At 1 hour, no difference between the 2 sides was observed; a mean of 17.4 pmoles/mg protein was observed from the side of the occlusion and 18.9 pmoles/mg protein from the contralateral side. At 3 hours, a mean value of 8.9 pmoles/mg protein on the ischemic side and a level of 21.7 pmoles/mg protein on the contralateral side were observed. At 24 hours, the cAMP level on the ischemic side remained below the nonischemic side; the values obtained were 13.7 pmoles/mg protein compared to 27.9 pmoles/mg protein compared to 27.9 pmoles/mg protein. These changes in cAMP as early as 3 hours after the onset of ischemia, when such a lesion is reversible, may indicate that in initial step in the alteration of cellular metabolism following ischemia is due to membrane perturbation and altered production of this second messenger.
"Stump" on internal carotid artery--a source for further cerebral embolic ischemia.
Authors: Barnett H J , Peerless S J , Kaufmann J C
Published: June 2011

A series of 9 patients have experienced hemisphere and retinal ischemia at an interval after occlusion of appropriate internal carotid arteries. All had radiological evidence of a persisting proximal stump to the occluded artery and, in most, pathological evidence of thrombotic material attached to atheromatous lesions within the stump. Thromboembolism from the stump via the anastomotic supply through ipsilateral common and external carotid arteries is thought to be responsible for the ischemic events to the brain or retina despite absence of flow through the internal carotid artery. Seven of the 9 were treated by surgical excision or obliteration of the stump and, when indicated, common and external carotid endarterectomy. Turbulence in the stump contributed to progressive atherosclerotic changes and probably aggravated thrombogenesis in this location with subsequent embolization into the anastomotic arteries.
Cerebral hemodynamics in Shy-Drager syndrome: variability of cerebral blood flow dysautoregulation and the compensatory role of chemical control in dysautoregulation.
Authors: Shinohara Y , Gotoh F , Takagi S
Published: June 2011

Cerebrovascular autoregulation and CO2 reactivity were measured repeatedly in 3 patients with the multiple system atrophy type of autonomic insufficiency (Shy-Drager syndrome) by means of the 133Xe injection method. The degree of cerebral blood flow (CBF) dysautoregulation showed day-to-day variations in 2 of the 3 patients. The CO2 reactivity was normal or supernormal in the supine position in patients with impaired autoregulation. In the head-up position the response to CO2 was slightly suppressed in 2 of the patients, suggesting that chemical control may have tended to compensate for CBF dysautoregulation. It is concluded that the mechanism of chemical control of the cerebrovasculature is different from that which controls autoregulation and may have partially compensated for CBF dysautoregulation.
Prediction of Early Stroke Risk in Transient Symptoms With Infarction
Authors: Arsava E. Murat , Furie Karen L. , Schwamm Lee H. , Sorensen A. Gregory , Ay Hakan
Published: June 2011

Background and Purpose—

The risk of stroke shortly after transient ischemic attack with infarction on diffusion-weighted images, also known as transient symptoms with infarction (TSI), is substantially higher than is the risk after imaging-normal transient ischemic attack. We sought to assess the utility of a Web-based recurrence risk estimator (RRE;
http://www.nmr.mgh.harvard.edu/RRE/
) originally developed for use in patients with ischemic stroke for predicting 7-day risk of stroke in patients with TSI.

Methods—

We calculated RRE and ABCD
2
scores in a retrospective series of 257 consecutive patients with TSI diagnosed by diffusion-weighted images within 24 hours of symptom onset. We defined subsequent stroke as clinical deterioration associated with new infarction spatially distinct from the index lesion. We assessed the predictive performance of each model by computing the area under receiver-operating characteristics curve.

Results—

Over 7-day follow-up, 16 patients developed a recurrent stroke (6.2%). The sensitivity and specificity of an RRE score of ≥2 for predicting 7-day stroke risk were 87% and 73%, respectively. The area under the receiver-operating characteristics curve was 0.85 (95% CI, 0.78–0.92) for RRE and 0.57 (95% CI, 0.45–0.69) for ABCD
2
score (z-test;
P
<0.001).

Conclusions—

The RRE score seems to predict 7-day risk of stroke after a TSI. If further validated in larger data sets, the RRE score could be useful in identifying high-risk patients with TSI who may benefit from early intervention with targeted stroke prevention strategies.
Local Brain Temperature Reduction Through Intranasal Cooling With the RhinoChill Device
Authors: Abou-Chebl Alex , Sung Gene , Barbut Denise , Torbey Michel
Published: June 2011

Background and Purpose—

Hypothermia is neuroprotectant but currently available cooling methods are laborious, invasive, and require whole-body cooling. There is a need for less invasive cooling of the brain. This study was conducted to assess the safety and efficacy of temperature reduction of the RhinoChill transnasal cooling device.

Methods—

We conducted a prospective single-arm safety and feasibility study of intubated patients for whom temperature reduction was indicated. After rhinoscopy, the device was activated for 1 hour. Brain, tympanic, and core temperatures along with vital signs and laboratory studies were recorded. All general and device-related adverse events were collected for the entire hypothermia treatment.

Results—

A total of 15 patients (mean age, 50.3±17.1 years) were enrolled. Brain injury was caused by intracerebral hemorrhage, trauma, and ischemic stroke in equal numbers. Hypothermia was induced for fever control in 9 patients and for neuroprotection/intracranial pressure control in 6. Core temperature, brain temperature, and tympanic temperature were reduced an average of 1.1±0.6°C (range, 0.3 to 2.1°C), 1.4±0.4°C (range, 0.8 to 5.1°C), and 2.2±2°C (range, 0.5 to 6.5°C), respectively. Only 2 patients did not achieve the goal of ≥1°C decrease in temperature. Brain temperature
,
tympanic temperature
,
and core temperature reductions were similar between the afebrile and febrile patients. There were no unanticipated adverse events and only 1 anticipated adverse event: hypertension in 1 subject that led to discontinuation of cooling after 30 minutes. There were no nasal complications.

Conclusions—

Intranasal cooling with the RhinoChill device appears safe and effectively lowers brain and core temperatures. Further study is warranted to assess the efficacy of hypothermia through intranasal cooling for brain-injured patients.
Rotating Stratified Barotropic Flow over Topography: Mechanisms of the Cold Belt Formation off the Soya Warm Current along the Northeastern Coast of Hokkaido
Authors: Mitsudera Humio , Uchimoto Keisuke , Nakamura Tomohiro
Published: June 2011

The Soya “Warm Current” (SWC) flows through a shallow strait between the Japan Sea and the Sea of Okhotsk. The SWC has a jet structure downstream of the strait along the northern coast of Hokkaido with a maximum speed exceeding 1 m s−1 at its axis in summer and fall. A surface cold belt with a subsurface doming structure forms offshore of the SWC axis. Mechanisms of the cold belt formation are discussed from a point of view of resonant interaction between a barotropic stratified flow and a shallow sill and subsequent baroclinic adjustment along the SWC. When a stratified current rides a slope upstream, the thermocline displaces upward greatly and outcrops owing to resonant generation of internal Kelvin waves if the upper layer is thinner than the lower layer. The control section, where a Froude number is unity, occurs “upstream” from the sill crest when the ambient inflow has a barotropic flow component. These upwelling features closely resemble those along the southwestern coast of Sakhalin Island. The SWC then flips from an upwelling-type to a downwelling-type structure; in doing so, it transits from the west coast of Sakhalin to the east coast of Hokkaido. It is this transition that leads to the offshore doming structure, which propagates downstream as a vorticity wave, manifesting the cold belt at the surface.
Multiculturalism and the catachresis of otherness: Settling Gypsies, unsettling Gypsy belongings
Authors: Theodosiou Aspasia
Published: June 2011

Triggered by Gypsy accounts about a European Union development project designed to create a Gypsy settlement in Parakalamos, a village on the Greek—Albanian border (in north-west Greece), the article draws attention to some of the deceptively brittle ways in which the recent emphasis on ‘recognition’, ‘visibility’ and ‘self-identification’ — in the context of discourses about multiculturalism — cannot be applied to all groups, and, under specific circumstances can lay the grounds for the catachresis (misuse and/or condemnation) of Gypsies’ ‘be-longing’ — its mis-recognition.
Effectiveness of resilient wheels in reducing noise and vibrations
Authors: Suarez B , Chover J A , Rodriguez P , Gonzalez F J
Published: June 2011

This study focuses on the effectiveness of resilient wheels in reducing railway noise and vibrations, and compares the effectiveness of three types of wheels. The finite element method has been used to characterize the vibratory behaviour of these wheels. The model has been excited with a realistic spectrum of vertical track irregularities, and a spectral analysis has been carried out. Results have been post-processed in order to estimate the sound power emitted. These calculations have been used to assess the effectiveness of the resilient wheel designs in reducing the noise emitted to the environment and in propagating structural vibrations.
Peacebuilding and culture in Bosnia and Herzegovina
Authors: Kappler Stefanie , Richmond Oliver
Published: June 2011

This article investigates problems and pitfalls involved in the EU’s peacebuilding activities in Bosnia and Herzegovina. It claims that by romanticizing civil society and selectively reinforcing existing power structures, the European Union has failed to give society a stake in the peace that is being created in that country. Against this background, the article goes on to argue that local responses and forms of resistance have begun to emerge in Bosnia and Herzegovina, challenging the EU’s peacebuilding mission to move towards a more contextualized engagement with local society. Rather than focusing exclusively on the EU’s formal institutional mechanisms, a more contextualized approach would seek to include a wide variety of local agencies and create a space in which Bosnian society might develop alternative versions of peace that relate to people’s everyday lives. The main challenge for the EU, the article concludes, is to take the diversity of Bosnia’s local voices seriously in efforts to promote a hybrid, sustainable peace.
Deconstructing civil war
Authors: Strand Håvard
Published: June 2011

The article by Jacob Mundy in this issue of Security Dialogue draws attention to the ongoing debate between deconstructivists and quantitative researchers. The article criticizes the current state of the ‘new literature on civil wars’ and offers some recommendations as to how this literature might be improved. Yet, as a scholar on the receiving end of it, I am unable to make use of Mundy’s critique. I do not understand the premises for his article; I am not convinced by the case of Algeria; and I am unable to understand the recommendations made at the end of the piece. In other words, the dialogue here is not working. In large parts, this failure in communication is due to the fact that the relevant literatures very rarely connect with each other. The use of concepts in Mundy’s article might represent one of the few occasions on which they do. I propose a set of recommendations that I hope might assist in rendering the dialogue between these currently estranged literatures less futile.
The Development of Transnational Higher Education in China
Authors: Fang Wenhong
Published: June 2011

This article presents an empirical study of transnational higher education in China at the institutional level. The units of analysis are the Chinese partner universities of transnational higher education programs. Through comparison of research universities and teaching universities, the study finds that transnational higher education programs are developed and perceived differently by these two categories of universities. For teaching universities, transnational higher education is mainly used to expand enrollment. It is the most active internationalization activity on campus. For research universities, especially top research universities, transnational higher education’s major function is to provide academic opportunities for those aspiring for advanced professional degrees. It is only one of the many internationalization activities on campus. Teaching universities tend to use transnational higher education more to generate revenue and reduce cost.