bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduced Nicotinamide Adenine Dinucleotide Fluorescence and Cortical Blood Flow in Ischemic and Nonischemic Squirrel Monkey Cortex. 1. Animal Preparation, Instrumentation, and Validity of Model
Authors: SUNDT THORALF M. , ANDERSON ROBERT E.
Published: June 2011

Reduced nicotinamide adenine dinucleotide (NADH) fluorescence was recorded from an avascular area on the squirrel monkey cortex prior to, during, and after focal incomplete ischemia. By using the instrumentation described, stable recordings were obtained free from hemoglobin artifact and with only minimal photodecomposition. Pentobarbital was compared to urethane and halothane as the anesthetic agent and was found acceptable for these types of studies in the dosages used. NADH levels were constant prior to ischemia, increased during ischemia, returned to pre-ischemic levels after restoration of blood flow, and then increased greatly at death produced by anoxia. The use of the infrared microscope for semiquantitative measurements of cortical blood flow throughout the duration of these acute studies was investigated and found to be reliable.
Lipid Composition of Cerebral Vessels in American Negroes, Caucasians and Nigerian Africans: A Comparative Study
Authors: TAYLOR G. O. , BARBER JESSE B. , JACKSON MARVIN A. , RESCH J. A. , WILLIAMS A. OLUFEMI
Published: June 2011

The lipid content of cerebral vessels from American Negroes, Caucasians and Nigerian Africans living in urban areas was chemically quantitated. There are significant differences between the total and free cholesterol content of the vessels among the three population groups. The American Negroes have the greatest amount of cerebral vascular cholesterol compared with American Caucasians and Nigerians. This confirms previous morphological observations that the severity and extent of cerebral atherosclerosis are greater in American Negroes than in American Caucasians and Africans. However, there is no significant difference in the phospholipid content of the cerebral vessels except among the female Negro groups. Chemical quantitation of lipids in vessels may be utilized for assessment of degree of atherosclerosis and may prove to be an acceptable and reliable alternative methodology for epidemiological studies.
Serum Lipids and Uric Acid Relationship in Ischemic Thrombotic Cerebrovascular Disease
Authors: BANSAL B. C. , GUPTA R. R. , BANSAL M. R. , PRAKASH C.
Published: June 2011

Serum lipids and serum uric acid have been studied in 50 patients with ischemic thrombotic Cerebrovascular disease. Patients having diseases known to predispose to hyperuricemia were excluded. Abnormalities of large vessels were present in 14 of 30 cases (46.6%) as a whole, and in 9 of 16 cases (56.5%) below 40 years of age. Thirty percent of the cases showed hyperuricemia. A statistically significant rise in serum triglycerides, pre-beta lipoproteins and serum uric acid was found in all 50 patients and in patients below 40 years of age. In patients above 40 years of age, only the rise in serum triglycerides and pre-beta lipoproteins was found to be statistically significant. A statistically significant rise in serum triglycerides, pre-beta lipoproteins, cholesterols and uric acid was found in patients with abnormal angiograms. A statistically significant correlation was observed between serum uric acid and serum triglycerides in all the groups, between serum uric acid and pre-beta lipoprotein in patients below 40 years of age, and between serum uric acid and serum phospholipids in patients with abnormal angiograms. These factors may be playing a role in the causation of ischemic thrombotic cerebrovascular disease in general and especially in patients below 40 years of age.
Artificial Embolization of the Middle Cerebral Artery in Primates
Authors: BREMER ALFONSO M. , WATANABE OSAMU , BOURKE ROBERT S.
Published: June 2011

Artificial embolization of the middle cerebral artery (MCA) was produced in the primate, with a technique similar to that described by Luessenhop and Spence (1960) for the treatment of an inoperable arteriovenous malformation in the territory of the MCA. Silicone spheres (1 to 1.5 mm in diameter) were introduced into the internal carotid artery (ICA) via the external carotid artery (ECA). Emboli (1 to 1.3 mm) passed into the anterior cerebral artery (ACA) in 12%, and into the MCA in 50%. Emboli (1.2 to 1.5 mm) stopped at the ICA bifurcation in 54%. In all primates (82.35%) in which the emboli occluded the ICA bifurcation or the MCA, immediate contralateral hemiplegia developed. The correlation of the anatomical characteristics of the intracranial vasculature of the ICA bifurcation, the diameter of the emboli, and the anatomical localization of the silicone spheres suggests that this experimental model can produce a selective acute "point" occlusion of the MCA in at least 75% of the cases without violating the cranium, in which the resultant changes in the distribution of water and electrolytes in the brain during the acute ischemic event in the territory of the MCA of the primate can be studied.
Cerebral Atherosclerosis and Its Relationship to Selected Diseases in Nigerians: A Pathological Study
Authors: WILLIAMS A. OLUFEMI , LOEWENSON RUTH B. , LIPPERT DOLORES M. , RESCH JOSEPH A.
Published: June 2011

Factors which are known to be associated with cerebral atherosclerosis were evaluated in Nigerian Africans. Of 465 autopsied adult Nigerians, 62 (13%) had cerebral atherosclerosis. The frequency and severity of atherosclerosis among Nigerians with hypertension, particularly male subjects, were higher than in normotensives. Although there was a similar frequency of hypertension among autopsied Nigerian and Minnesota Caucasian populations, the severity and extent of atherosclerosis were greater in the Minnesota population. The relatively short duration of hypertension in the Nigerian before death might be an important factor which did not permit progressive development of cerebral atherosclerosis. Other factors which predisposed the Nigerian to increased frequency and severity of atherosclerosis included increased heart weight and diabetes mellitus. The relatively low frequency of cerebrovascular disease in the Nigerian may be explained on the basis of a low degree of cerebral atherosclerosis and relatively short duration of hypertension.
Influence of Anesthetics on Metabolic, Functional and Pathological Responses to Regional Cerebral Ischemia
Authors: MICHENFELDER JOHN D. , MILDE JAMES H.
Published: June 2011

Regional cerebral ischemia was produced by common carotid artery occlusion in gerbils and by middle cerebral artery occlusion in dogs, cats, and squirrel monkeys. Anesthesia was induced with either pentobarbital or halothane and maintained for two to there hours after vessel occlusion. In acute studies, the effect of regional cerebral ischemia on cerebral concentrations of ATP, phosphocreatine, lactate, and pyruvate was determined at the end of this period in gerbils, cats, and squirrel monkeys. In chronic studies, the degree of neurological deficit and size of cerebral infarction were determined 48 hours after a two-hour to three-hour period of vessel occlusion in cats and squirrel monkeys and permanent occlusion in dogs. In gerbils, dogs, and cats, there were no differences in the metabolic, functional, or pathological effects of anesthesia with pentobarbital or halothane. However, in the squirrel monkey, in acute studies the metabolic alterations were significantly less with pentobarbital, and in chronic studies the frequency and magnitude of functional deficits and cerebral infarction were significantly less. We conclude that pentobarbital does provide a degree of protection during regional cerebral ischemia but that such effects are only consistently demonstrable in primates. In nonprimates, we assume that variability in the collateral circulation renders demonstration of significant differences difficult or impossible.
Regional Cerebral Blood Flow Response to Hypocapnia in the Contralateral Hemisphere of Patients With Acute Cerebral Infarction
Authors: MELAMED ELDAD , LAVY SYLVAN , PORTNOY ZIPPORA
Published: June 2011

The rCBF response to hypocapnia induced by active short-term hyperventilation was determined in the contralateral hemispheres of ten patients with acute unilateral cerebral infarction. Overall rCBF reduction occurred in only two patients. Regional or widespread abnormal responses to Paco
2
reduction manifested as either no change or a paradoxical increase in the rCBF were observed in eight patients. The hemispheric mean rCBF reduction following hypocapnia was diminished as compared with control subjects. Our findings suggest that an impairment of the chemical control of rCBF may occur in the non-infarcted hemisphere during the early period following the onset of cerebral infarction. The pathophysiological mechanisms which may underlie this abnormal rCBF reactivity to Paco
2
, reduction are considered.
Sympathetic Innervation of Cerebral Arteries: Prejunctional Supersensitivity to Norepinephrine After Sympathectomy or Cocaine Treatment
Authors: EDVINSSON L. , AUBINEAU P. , OWMAN C. , SERCOMBE R. , SEYLAZ J.
Published: June 2011

The inactivation of the norepinephrine transmitter in the region of the adrenergic receptor is one important function of the sympathetic nerve terminals innervating blood vessels. This capacity was tested on isolated cat's middle cerebral artery (MCA) by recordings of the contractile response induced by norepinephrine at various stages after sympathectomy (excision of the superior cervical ganglion). Within three days after denervation, when fluorescence microscopy revealed a disappearance of neuronal norepinephrine in the vessel wall, there was a threefold increase in sensitivity of the test system which was not further enhanced at two weeks. This, and the finding of a similar amount of sensitization (of non-denervated vessels) to norepinephrine or tyramine after cocaine treatment, showed that a prejunctional type of sensitivity had developed. The sympathetic denervation did not influence the dose-response curve obtained with acetylcholine, supporting the specific nature of the supersensitivity reaction only to the sympathetic transmitter. Half a year after sympathectomy the sensitivity of the pial arteries to norepinephrine returned to control levels despite the absence of reinnervation, indicating that postjunctional changes also occurred. The findings offer further evidence for a functional role of the sympathetic nerves supplying intracranial arteries and show that the mode of innervation resembles that found in peripheral vessels.
Localization of Apo-Lipoproteins in Human Carotid Artery Plaques
Authors: HOFF HENRY F. , HEIDEMAN CAROL L. , NOON GEORGE P. , MEYER JOHN S.
Published: June 2011

Apoproteins from plasma lipoproteins were localized by immunofluorescence techniques in human carotid artery atherosclerotic lesions. These studies were performed in light of the possible importance of these apoproteins in both lipid metabolism and the pathogenesis of atherosclerosis. ApoA-I from high density lipoproteins, apoB from low density lipoproteins, and apoC-III from very low density lipoproteins were localized also as markers for their respective lipoproteins, since the latter cross-react immunologically. The three apoproteins were localized to the same regions of lesions as neutral lipids and, to some extent, fibrinogen. These regions consisted of bands of collagen fibers, usually deeper within the lesion, and the lipid core or atheroma of such advanced lesions. Although the superposition of localization for the three apoproteins and lipid was only 53%, it was suggested that deviation from complete superposition was due to the abrupt changes in lesion structure resulting from the focal nature of the atherosclerotic process. These results suggest that there is a broader specificity than previously implied of the interaction between such lesion components as connective tissue and extracellular lipid accumulations, and apoproteins from plasma lipoproteins. This interaction is believed to result in a net retention within atherosclerotic lesions of human extracranial arteries of these plasma-derived factors, either as free apoproteins or as native lipoproteins.
Effect of Cyclandelate on Dementia
Authors: WESTREICH GILBERT , ALTER MILTON , LUNDGREN SANDRA
Published: June 2011

Cyclandelate, a vasodilator, was administered to 24 patients with dementia. The dementia in these patients was presumed to be due to cerebral ischemia caused by atherosclerosis in cerebral vessels after other possible causes were ruled out. In a double-blind, cross-over study, patients received 200 mg of cyclandelate four times daily for six weeks and a placebo for six weeks. Six psychological tests, which reflect various aspects of higher cortical ability, were used to evaluate the effect of cyclandelate on the dementia. Cyclandelate was found to be no more effective than placebo in improving higher cortical function in these demented patients.
Kinks, Coils, and Carotids: A Review
Authors: DESAI BINDU , TOOLE JAMES F.
Published: June 2011

Kinking and coiling of the internal carotid artery (ICA) sometimes may result in symptomatic cerebrovascular disease, but indisputable evidence linking the two conditions is lacking. However, there is enough evidence to warrant careful consideration of surgical correction in patients who have features of the carotid artery syndrome and kinking of the ICA as shown on angiography. Kinking or buckling of the artery is due to atherosclerosis and is to be distinguished from coiling, which is ascribed to embryological causes.

Definite recommendations regarding the advisability of surgery for infants who are discovered to have coils cannot be made, but coiling is generally asymptomatic. Adults with kinks in their carotid arteries who have recurrent transient ischemic attacks (TIAs) benefit most from surgical correction, particularly if symptoms are aggravated on head rotation, which may cause the kink to obstruct.
The Effect of a Simulated Subarachnoid Hemorrhage on Cerebral Blood Flow in the Monkey
Authors: MARTINS ALBERT N. , DOYLE THOMAS F. , NEWBY NORWYN , KOBRINE ARTHUR I. , RAMIREZ ARCHIMEDES
Published: June 2011

The hydrogen clearance method was used to measure local and total cerebral blood flow (CBF) in the rhesus monkey before and for five hours after a simulated subarachnoid hemorrhage (SAH). CBF remained stable after SAH unless SAH was associated with a fall in cerebral perfusion pressure. In addition, cerebrovascular resistance did not increase after SAH. These results suggest that vasoactive agents in fresh whole blood, and the arterial spasm they produce when added to cerebrospinal fluid (CSF), play only a limited role in the pathogenesis of ischemic encephalopathy that follows an SAH.
Effects of Oxygen Saturation and Pco
2
on Brain Uptake of Glucose Analogues in Rabbits
Authors: BERSON FRANK G. , SPATZ MARIA , KLATZO IGOR
Published: June 2011

The effect of oxygen saturation and Pco
2
on brain uptake of glucose analogues was studied in rabbits. Using a modified Oldendorf technique,
14
C-labeled glucose analogues with a
3
H
2
O reference standard were introduced into the cerebral circulation via the common carotid artery, and the radioactivity of the ipsilateral cerebral cortex was counted and expressed in terms of a brain uptake index (BUI).

Severe hypoxia (oxygen saturation ≤ 18%) resulted in approximately a 40% decrease in the BUI of 2-deoxy-D-glucose and a 45% decrease in the BUI of 3-0-methyl-D-glucose. Severe hypercapnia (Pco
2
, = 100 mm Hg) caused a 45% decrease in the BUI of both of these glucose analogues. Hypercapnia superimposed on severe hypoxia had no additional effect. Hypocapnia (Pco
2
= 15 mm Hg) increased the BUI of 3-0-methyl-D-glucose by 35% of the control value, and this increase was extremely sensitive to competitive inhibition. When BUI values were plotted against pH rather than Pco
2
, for the same experiments, there was a good correlation with the calculated linear regression.

These results are compared with previous findings on pathologically induced changes in brain uptake of glucose analogues, and the possible role of blood flow is considered in detail.
Noninvasive diagnosis of carotid occlusion by ocular pneumoplethysmography.
Authors: Gee W , Oller D W , Wylie E J
Published: June 2011

An ocular pneumoplethysmograph was devised to measure the systolic pressure in the ophthalmic artery and to obtain calibrated pulse volume changes from the ocular globe, with simultaneous recording from both eyes. The instrument is self-contained and portable. It can be applied by paramedical personnel, and the graphic recording is readily interpreted by the physician. It has proved to be 100% accurate in noninvasively detecting unilateral carotid occlusion or preocclusive stenosis. This technique, when combined with carotid compression, has been shown to be most valuable in assessing the tolerance of a cerebral hemisphere to proximal carotid occlusion. It was used to evaluate a wide variety of carotid arterial lesions. Elective carotid resection without graft replacement and urgent and elective carotid ligations were performed, based on the preoperative prediction that such procedures would be tolerated without neurological injury. The instrument and the technique of its application are simple, safe, and accurate.
Alterations in behavior, brain electrical activity, cerebral blood flow, and intracranial pressure produced by triethyl tin sulfate induced cerebral edema.
Authors: Marshall L F , Bruce D A , Graham D I , Langfitt T W
Published: June 2011

The interrelationships between cerebral edema, intracranial pressure (ICP), and cerebral blood flow (CBF) were studied in acute and chronic triethyl tin sulfate treated rats. Prior to pentobarbital anesthesia behavioral observations were made. ICP and regional CBF were measured under steady state conditions and brain water content was determined by vacuum drying of the right cerebral hemisphere. Control and chronic animals were neurologically normal. There were two distinct acute groups: (1) acute low pressure (ALP) animals - alert but tetraperetic, and (2) acute high pressure (AHP) animals - deeply stuporous, with minimal pain response and gross EEG slowing. ICP was significantly elevated only in AHP animals. Hemispheric CBF was significantly reduced in AHP and chronic animals. The interaction of increased pressure and edema (AHP) produced the greatest decrease in CBF, although deep white flows were significantly affected in all experimental groups. Chronic animals had significantly lower flow in four of seven regions compared to ALP animals despite no significant difference in ICP. Water content was significantly increased in all experimental groups with the greatest increase in the chronic animals. In the absence of any significant increase in ICP, cerebral edema appears to cause a significant reduction in cerebral blood flow and this reduction corresponds with the magnitude and location of the edema.
Brain microvascular hemodynamic responses to induced seizures.
Authors: Myers R R , Intaglietta M
Published: June 2011

Arteriolar diameters and venular erythrocyte velocities in the small pial vessels on the surface of the cat brain were measured by TV methods during induced epileptic seizures through a cranial window. Grand mal seizures maximally dilated arterioles and increased venular erythrocyte velocity up to 400%. High positive correlation existed between changes in CSF hydrogen ion concentration and pial arteriolar diameter, suggesting metabolic regulation of CBF through CSF/interstitial fluid hydrogen ion alterations during the seizure.
A pilot study of urokinase therapy in cerebral infarction.
Authors: Fletcher A P , Alkjaersig N , Lewis M , Tulevski V , Davies A , Brooks J E , Hardin W B , Landau W M , Raichle M E
Published: June 2011

Thirty-one patients with acute cerebral infarction were treated with the thrombolytic agent urokinase for either a single or a double infusion period, each of ten hours. The effects of urokinase therapy administered at dosage rates of 1,200, 1,500 or 1,700 CTA urokinase units per pound of body weight per hour were followed by serial blood coagulation and other biochemical studies. In the dosage used, urokinase produced a prompt sustained increase, 20-fold to 40-fold, of plasma thrombolytic activity with relatively minor disturbance of the blood coagulation system. Nevertheless, hemorrhagic complications occurred in several patients and distinctly favorable therapeutic effects were not observed.
Recovery of the cortical evoked response following temporary middle cerebral artery occlusion in baboons: relation to local blood flow and PO2.
Authors: Branston N M , Symon L , Crockard H A
Published: June 2011

The degree of recovery of the somatosensory cortical evoked response following a period (15 to 65 minutes) of partial ischemia, produced by temporary occlusion of the middle cerebral artery (MCA), was assessed in baboons and related to the local tissue blood flow and PO2 before, during and after the occlusion. Flow was measured using the technique of two-minute hydrogen clearance. Failure of complete recovery of the evoked response was associated with significantly greater depths of ischemia and tissue hypoxia during occlusion, and with significantly greater and persisting tissue hypoxia after occlusion, than complete recovery. Complete recovery of the evoked response also was associated with tissue hyperoxia after occlusion. The reduced postocclusive PO2 levels associated with incomplete recovery of the evoked response suggest that reduced perfusion during ischemia was sufficiently severe to cause some degree of irreversible anoxic damage. The effect of a brief (three to ten minutes) period of ventilation with air (instead of oxygen) under such low-flow conditions was to depress the evoked response significantly further; normally perfused brain, however, was unaffected by this procedure. This finding has clinical implications in regard to normobaric oxygen therapy.
A model for spasm of the anterior cerebral artery.
Authors: Peters N D , Di Chiro G
Published: June 2011

A model for production of spasm of the anterior cerebral artery in primates is presented. The model consists of injection of 0.35 cc of fresh blood into the chiasmatic cistern through the optic canal after orbital exenteration. Clinical and angiographical follow-up is possible. The clinical appraisal of acute and chronic changes can be accomplished in the awake animal.
Cerebral Ischemia in Gerbils: Differential Vulnerability of Protein, RNA, and Lipid Syntheses
Authors: YANAGIHARA T.
Published: June 2011

In order to compare the difference in the vulnerability of macromolecular syntheses, protein, RNA, and lipid syntheses were studied with ischemic brain tissue three hours following unilateral carotid ligation in gerbils. Precursor incorporation was measured in various subcellular fractions following in vitro incorporation with brain slices. There was marked inhibition of protein synthesis, but RNA and phospholipid syntheses showed little or no change. On the basis of available information on rapid deterioration of polysomal system for polypeptide synthesis, a hypothesis was proposed that messenger ribonucleic acid (RNA) at the polysomal level is promptly affected in this pathophysiologic condition.
Clinical implications of the Doppler cerebrovascular examination: a correlation with angiography.
Authors: Bone G E , Barnes R W
Published: June 2011

A directional Doppler ultrasound cerebrovascular examination was compared with angiographical findings of 152 internal carotid arteries. The Doppler examination was abnormal in 36 of 38 (95%) arteries with occlusion or stenosis greater than 75%. Of 63 arteries with lesser degrees of stenosis, the Doppler examination identified only four. There were no false-positive Doppler examinations. If the decision to perform angiography had been predicated exclusively on the presence of abnormal Doppler findings, 61 of 101 (60%) carotid lesions of potential clinical significance would have been overlooked. While the Doppler ultrasound cerebrovascular examinations is the most useful noninvasive technique available for the evaluation of certain specific categories of patients with cerebrovascular disease, the technique is based on hemodynamic alterations of pressure and flow, and cannot be expected to identify the relatively large number of non-hemodynamically significant carotid lesions that are still clinically significant as sources of emboli. This paper illustrates that in the routine evaluation of patients with symptomatic cerebrovascular disease, the Doppler examination should not play a part in the decision to proceed with angiography.
Blood coagulation and plasma fibrinolytic enzyme system pathophysiology in stroke.
Authors: Fletcher A P , Alkjaersig N , Davies A , Lewis M , Brooks J , Hardin W , Landau W , Raichle M E
Published: June 2011

Plasma fibrinogen chromatography is a method for quantification of high molecular weight fibrinogen complexes (HMWFC), native fibrinogen and other fibrinogen derivatives in plasma. Enchanced formation of fibrin, intravascular coagulation, thrombus formation, etc., are reflected by elevation of plasma HMWFC, and the method distinguishes between subjects with normal and pathological rates of fibrin formation. Serial standard blood coagulation assays, including plasma fibrinogen chromatography, and neurological studies were performed on 220 patients admitted to a stroke unit. Findings from patients with cerebral infarction were compared against those of three control groups: (1)normals, (2)a stroke control group and(3)a stroke risk factor group. Plasma HMWFC findings were significantly (p less than 0.001) higher in the stroke risk factor group than in the normals. Plasma HMWFC values were significantly higher (p less than 0.001) in the cerebral infarction patients than in any of the control groups, and plasma fibrinogen, plasminogen, alpha1-antitrypsin and alpha2-macroglobulin also were significiantly higher (p less than 0.001) in the patients. The greater the degree of initial neurological deficit, the greater were plasma HMWFC values (p less than 0.001), and high HMWFC values were associated with poor clinical outcome. Plasma HMWFC values were significantly higher (p less than 0.001) in patients with intracerebral hemorrhage, subarachnoid hemorrhage and cerebral embolism. These findings docunment the fact that a high proportion of stroke patients have coagulopathy, characterized by pathological enhancement of fibrin formation.
Intracranial neurosurgical treatment of occlusive cerebrovascular disease.
Authors: Salazar J L , Amine A R , Sugar O
Published: June 2011

Anastomosis of the extracranial superficial temporal artery to the intracranial middle cerebral artery offers an additional source of blood to the cerebral circulation in patients with transient ischemic episodes. Fourteen cases are reported. Two representative cases with three anastomoses demonstrate the use of this technique in occlusion of the internal carotid artery, occlusion of the middle cerebral artery and stenosis of the middle cerebral artery. Indications and contraindications of the procedure are discussed.
Carotid blood velocity during cough studies in man.
Authors: Desser K B , Harris C L , Benchimol A
Published: June 2011

Utilizing a Doppler ultrasonic flowmeter catheter, right carotid artery blood velocity was measured during 91 coughing episodes in 16 patients. Such coughing reduced carotid blood velocity by 40 +/- 22% (control = 34 +/- 8 cm per second, cough = 20 +/- 9 cm per second, p less than 0.001). There was an insignificant low degree of corrleation between the level of simultaneously recorded mean right pressure and the percent decline of peak carotid blood velocity, suggesting that impaired venous return was not the only factor responsible for the observed changes. It is concluded that (1)coughing diminishes phasic carotid blood velocity and (2)reduced cerebral perfusion may play a role in the pathogenesis of cough syncope.
Aphasia outcome in stroke: a clinical neuroradiological correlation.
Authors: Yarnell P , Monroe P , Sobel L
Published: June 2011

Fourteen aphasic patients with acute onset of thromboembolic cerebrovascular insults demonstrable by angiography or radioscintigrams who were available for long-term follow-up have been studied. Their aphasia evolution was compared with acute angiographical and radioisotopic findings, and the lesions shown by follow-up computerized axial tomography (CT). Angiographical site of occlusion, evidence of early reopening of occluded vessels, and radioisotopic flow asymmetries including the "hot-stroke" luxury perfusion failed to correlate with aphasia outcome. Radioisotopic static images were more helpful by depicting lesion location and number but lacked the definition seen on the CT scan. The long-term CT scan by showing the size, location and number of lesions had a good correlation with aphasia outcome. Those patients with large dominant hemisphere involvements, either one large or many smaller lesions, fared poorly while those with lesser lesions did better. Bilateral lesions, at times evasive clinically, helped to account for significant aphasia residuals.
Bruits, ophthalmodynamometry and rectilinear scanning on transient ischemic attacks.
Authors: Yuson C P , Toole J F
Published: June 2011

One hundred seventeen patients with clinical signs and symptoms of transient ischemic attacks (TIAs) were evaluated. All underwent clinical evaluation for bruit, ophthalmodynamometry, rapid sequence scintiphotography with rectilinear scanning and four-vessel cerebral angiography. The results of these tests were compared for reliability in predicting location of lesions causing transient ischemic attacks. Angiography remains the most accurate procedure in evaluating extracranial vascular lesions. When determination of bruits, ophthalmodynamometry and brain scanning are done together, accuracy is greater than when any one of the procedures is done alone.
Angiographical extravasation of contrast medium in hemorrhagic infarction. Case report.
Authors: Irino T , Taneda M , Minami T , Murata Y
Published: June 2011

Leakage of the contrast medium was noted on angiograms of a patient whose autopsied brain disclosed typical pathological findings of hemorrhagic infarction. The case was a 63-year old woman with mitral valve failure, who suddenly had loss of consciousness and right-sided hemiplegia. The left carotid angiography performed six hours after onset demonstrated middle cerebral arterial axis occlusion, and the second angiography performed three days after onset displayed recanalization of the initially occluded artery as well as extravasation of the contrast medium. Fourteen days after onset the patient died and an autopsy was performed. The brain demonstrated perivascular punctate hemorrhages in the area supplied by the middle cerebral artery, and neither hematoma nor microaneurysm was disclosed pathologically. A short discussion is given on the possible relationship between recanalization and hemorrhagic infarction. The clinical assessment of hemorrhagic infarction has not been established successfully.
Regional cerebral blood flow in the anesthetized mouse as measured by local hydrogen clearance.
Authors: Rosenblum W I
Published: June 2011

Platinum microelectrodes were used to measure H2 clearance in mouse brain, and the clearance curves were used to calculate regional cerebral blood flow (rCBF). The curves were usually biexponential, whether or not electrode placement was confined to the cortex. When calculated by the height over area method, rCBF in anesthetized mice averaged 37+/-14 and 49+/-15 ml/100 gm per minute in two successive groups where cortical placement had been made. After CO2 breathing, which raised PaCO2 to 77+/-18 torr, the mean rCBF of the latter group was elevated to 70+/-36 ml/100 gm per minute. Our basal rCBF values are lower than literature values for rats or mice, when compared with data obtained by other techniques. However, our data are comparable to rat rCBF data obtainted by others using H2 electrodes and are comparable also to data for whole brain CBF obtained by a variety of methods in larger anesthetized mammals. It is possible that H2 electrodes provide low values for supposedly "cortical" rCBF in the very small mouse brain, because is such brains the electrode is usually close enough to a slow clearing compartment for the electrode reading to be influenced by that compartment. At the same time one cannot rule out the possibility that other techniques when applied to small rodents may, on occasion, produce spuriously high values for CBF. Indeed, while some studies using the latter techniques do show unusually high values for cortical flow in these animals, other studies using similar methods do not.
XIV. Cerebral ischemia: the role of thrombosis and of antithrombotic therapy. Study group on antithrombotic therapy.
Authors: Genton E , Barnett H J , Fields W S , Gent M , Hoak J C
Published: June 2011

A revival of interest in antithrombotic agents for the treatment of ischemic cerebrovascular disease has resulted in the widespread use of oral anticoagulants for the prophylaxis and therapy of the ischemic variety of stroke, and has generated enthusiasm for the use of platelet-suppressant agents such as aspirin, dipyridamole, and sulfinpyrazone. In delineating the several clinical types of focal ischemic disease and outlining the causes of cerebral ischemia and infarction, the study group considers the problems of data interpretation in the face of inconsistent terminology. The basic mechanisms of hemostasis and thrombogenesis are concisely detailed. Finally, the study group critically reviews extensive earlier reports of clinical trials of anticoagulants, platelet function suppressants, and thrombolytic agents, and reassesses according to present-day statistical standards the significance of the results. The information contained in this report should familiarize the reader with sufficient data to permit him to utilize antithrombotic agents under a variety of circumstances and to appreciate the contraindications and potential dangers in their use.
Reassessment of cerebral capillary changes in acute global ischemia and their relationship to the "no-reflow phenomenon".
Authors: Fischer E G , Ames A , Hedley-Whyte E T , O'Gorman S
Published: June 2011

Electron and light microscopic studies were performed on rabbit brain to re-examine the structural changes of endothelial cells and perivascular glia following ischemia. Although swelling of perivascular glia occurred, earlier findings of extreme perivascular glial swelling and bleb formation leading to luminal collapse and plugging could not be confirmed. Ischemic brains, however, had a higher proportion of small-diameter capillaries than controls. It is felt that structural changes in ischemic capillary walls in themselves are not sufficient to explain failed cerebral reperfusion, or the no-reflow phenomenon.
Experimental regional cerebral ischemia in the middle cerebral artery territory in primates. Part 2: Effects on brain water and electrolytes in the early phase of MCA stroke.
Authors: Watanabe O , West C R , Bremer A
Published: June 2011

Acute regional cerebral ischemia was produced in the middle cerebral artery (MCA) territory in monkeys (Macaca mulatta) by selective embolization of the internal carotid (ICA) bifurcation with minimum surgical intervention in the neck under sedated conditions. Two of five hours after embolization, brain water (measurement of dry weight) and tissue concentration of sodium and potassium were determined in the tissues of the sylvian cortex, putamen and subcortical white matter in the affected MCA territory. As early as three hours, initial increase in brain water was detected in the samples of the putament without noticeable change in tissue electrolytes in two of three animals. Gross ischemic swelling of the gray matter, in both the sylvian cortex and putamen, became obvious in six of eight animals after four to five hours. This swollen gray matter showed marked increase in brain water (up to 36% swelling), increase in tissue sodium (up to 100% of the control value), and decrease in tissue potassium (down to 55%). On the other hand, edema in the white matter, if present at all, was minimal without detectable change in tissue electrolytes and was always accompanied by much greater ( greater than two to seven times) edema in the gray matter. Thus, the gray matter edema, in both the deep subcortical structures and the cortex, appeared to play the major role in the development of hemispheric swelling of the brain which may begin within hours of the onset of the MCA stroke in monkeys. Microscopically, the swollen gray matter which showed more than 10% swelling with a definite shift of tissue sodium and potassium content appeared to be dead tissue. However, early edema in the gray matter which showed less than 10% swelling without detectable change in electrolytes might be caused by simple diffusion of water through the dysfunctional capillary wall or cell membrane with or without a permeability gradient between the intravascular cerebrospinal fluid and cerebral tissue compartment and might possibly be reversible.
Local mechanism of CO2 action of cat pial arterioles.
Authors: Kontos H A , Wei E P , Raper A J , Patterson J L
Published: June 2011

The effect of local hypercapnic acidosis or local hypocapnic alkalosis on pial arterioles were studied in anesthetized cats equipped with a cranial window for the direct observation of the pial microcirculation of the parietal cortex. Changes in PCO2 and pH of the extracellular fluid were induced by perfusing the space under the cranial window with artificial cerebrospinal fluid equilibrated with different concentrations of CO2, while PaCO2 was maintained constant. Hypercapnic acidosis dilated and hypocapnic alkalosis constricted pial arteioles markedly. The results indicate that a basis exists for considering CO2 as a mediator for local regulation of brain blood flow. The vasodilation associated with arterial hypercapnia was abolished by a reduction in CSF PCO2 equal in magnitude to the rise in arterial blood PCO2, suggesting that the action of CO2 is entirely local.
Amaurosis fugax.
Authors: Mungas J E , Baker W H
Published: June 2011

We reviewed 112 patients with amaurosis fugax to refine our indications for carotid angiography. Eighty patients had a carotid endarterectomy. Thiry-four patients with ipsilateral hemispheric transient ischemic attacks plus amaurosis fugax all had an operable carotid lesion. The presence or absence of a carotid bruit, a normal or abnormal ophthalmologic examination, or a normal or abnormal cerebrovascular Doppler examination did not predict which patients would or would not have an operable carotid lesion. All patients with amaurosis fugax being evaluated for an operable carotid stenosis require angiography.
The anterior communicating artery has significant branches.
Authors: Crowell R M , Morawetz R B
Published: June 2011

The anterior communicating artery was studied with the operating microscope in 10 autopsy cases. This vessel was present in all cases with reduplication in three. Arterial diameter ranged from 0.8 to 2.3 mm, with lengths of 5 to 10 mm. Branches of the anterior communicating artery were found in every case (range 3-13, average 5.4). Most branches were small (50-250 mu), but at least one large branch (250-1000 mu) was invariably present. Small ventral branches ramified on the optic chiasm. Small and large dorsal branches distributed themselves to lamina terminalis, hypothalamus, parolfactory areas, columns of fornix, and corpus callosum. Injury to these vessels caused by aneurysmal rupture or surgical manipulation may lead to serious clinical deficits.
Controlled trial of aspirin in cerebral ischemia.
Authors: Fields W S , Lemak N A , Frankowski R F , Hardy R J
Published: June 2011

Adouble-blind trial of aspirin for the treatment of cerebral ischemia was begun in 1972 and continued for 37 months. This was accomplished despite difficulties in controlling a long-term study of a drug which has widespread availability and consumption. The study design, criteria for selection of patients, follow-up surveillance, and methods of data analysis are presented. We report only subjects without carotid surgery before randomization. Patients (178) who had carotid transient ischemic attacks (TIAs) were randomly allocated to aspirin or placebo and followed to determine the incidence of subsequent TIAs,death, cerebral infarction or retinal infarction. Analysis of the first six months of follow-up revealed a statistically significant differential in favar of aspirin when death or cerebral or retinal infarction and the occurrence of TIAs were grouped and considered together as end points. Significance in favor of aspirin treatment was mainly revealed in patients with a history of multiple TIAs and was most evident in those individuals having carotid lesions appropriate to the TIA symptoms. It cannot be inferred from this study that aspirin prevents stroke because when end points were restriced to death or cerebral or retinal infarction, there was no statistically significant differential between the aspirin and placebo treatments.
Possible prevention of brain stem stroke by microvascular anastomosis in the vertebrobasilar system.
Authors: Khodadad G , Singh R S , Olinger C P
Published: June 2011

Four patients with symptoms and signs of brain stem ischemia due to occlusive disease of the vertebrobasilar system and one patient with similar cerebrovascular disease who was thought to be prone to brain stem stroke underwent a microvascular anastomosis between the occipital artery and the caudal loop of the posterior inferior cerebellar artery. There was no morbidity of mortality and neurologically all patients improved. Post-operative angiograms showed patent anastomosis in all the patients and improved circulation in three. This new operation may prove beneficial in a selected group of stroke patients who suffer from vertebrobasilar insufficiency and cannot be treated with gross surgical techniques.
Cerebrovascular response to infused 5-hydroxytryptamine in the baboon. Part 1. 5-Hydroxytryptamine infusion.
Authors: Mendelow A D , Eidelman B H , McCalden T A , Rosendorff C
Published: June 2011

Cerebral blood flow was measured in 17 baboons before and during infusion of 5-hydroxytryptamine (5-HT) into the internal carotid artery. The mean values for total cerebral blood flow, grey matter flow, and white matter flow before 5-HT infusion were 40.8, 59.2, and 12.7 ml/min/100 gm of tissue, respectively. There was no significant alteration in total blood flow or flow through grey matter when 5-HT was infused at dosages ranging from 0.5 to 10.0 microng/kg/min. A small but significant decrease in white matter blood flow was recorded when 5-HT was infused at a rate exceeding 2.5 microng/kg/min. The study indicates that in vivo, with the xenon clearance method, intra-arterial infusion of 5-HT does not significantly alter cerebral blood flow.
Epidemiological investigation of cerebrovascular disease in Iceland, 1958-1968 (ages 0-35 years): a total population survey.
Authors: Gudmundsson G , Benedikz J E
Published: June 2011

This study was undertaken to estimate the incidence of cerebrovascular disease in the age group 0-35 years in the population of Iceland during the 11 year period 1958 through 1968. The incidence for the whole country was 7.9/100,000-- males 7.5 and females 8.4. The incidence in Reykjavik, 8.3/100,000, was not significantly different from the rest of the country (7.2/100,000)nor was there any significant difference between the sexes. Comparison is made with similar studies.
An ultrastructural assessment of an embolic method of producing cerebral ischemia.
Authors: Dodson R F , Miyakawa Y , Wai-Fong Chu L , Ishihara N , Naritomi H , Hsu M C , Deshmukh V D
Published: June 2011

This study presents ultrastructural confirmation of the embolic method of producing an ischemic lesion. The embolic method was shown to produce more advanced parenchymal changes than those reported for the same postocclusion period following vascular clipping. With this method there was less alteration in the morphological intergrity of occluded extraparenchymatous areas of the arterial bed, especially in the associated nerve bundles.
Cathecholamine and 5-hydroxytryptamine levels in ischemic brain. Influence of p-chlorophenylalanine.
Authors: Welch K M , Chabi E , Buckingham J , Bergin B , Achar V S , Meyer J S
Published: June 2011

The effect of ischemia on catecholamine and 5-hydroxytryptamine (5-HT) levels in brain cortex was examined in the gerbil stroke model. Unilateral common carotid artery occlusion produced bilateral decrease in cortical dopamine levels in gerbils both symptomatic and asymptomatic of cerbral ischemia. The 5-HT progressively decreased only in the occluded hemisphere of ischemic animals. In p-chlorophenylalanine (PCPA)-treated gerbisl, dopamine decreased only in the occluded hemisphere of symptomatic animals, but norepinephrine became decreased bilaterally compared with controls. The 5-HT decrease was twice that seen in untreated animals. It is suggested that these results indicate initial release together with reduced synthesis of monoamines in ischemic brain. The incidence of ischemia induced by carotid occlusion decreased from 44% to 26% in PCPA-treated animals, which also suggests that depletion of 5-HT available for neuronal release prior to the induction of ischemia may reduce stroke incidence by limiting impairment of collateral vasocapacitance. PCPA pretreatment did not influence the development of edema in the occluded hemisphere of ischemic animals once ischemia was established.
Basilar artery occlusion: clinical and radiological correlation.
Authors: Archer C R , Horenstein S
Published: June 2011

Twenty patients with basilar artery occlusion and three patients with bilateral vertebral artery occlusions have been studied. The clinical data at the time of the ictus and the long-term follow-up data have been correlated with the site and extent of the basilar artery occlusion and the type of collateral flow. Patients with hypertension and with coma at the outset have a grave prognosis. The presence of surface collateral flow may not indicate adequate perfusion of the paramedian penetrating branches of the basilar artery or the thalamoperforating branches of the posterior communicating or posterior cerebral arteries. It is these vessels which supply the territory regulating the level of consciousness and containing some of the control mechanisms for respiratory function.