bluuebunny/crossref_metadata_2025 huggingface dataset:
Familial Incidence of Cerebral Hemorrhage
Authors: MARSHALL JOHN
Published: June 2011

The frequency of death certified as due to cerebral hemorrhage among the brothers and sisters of 180 index patients with a proved cerebral hemorrhage has been compared with its frequency in the population of the same age and sex at the same decennium of the century as given by the Registrar General. There was no statistically significant excess of death certified as due to cerebral hemorrhage except among the brothers of female index patients (p < 0.05). The significance of this finding is discussed.
A Study of Regional Autoregulation in the Cerebral Circulation to Increased Perfusion Pressure in Normocapnia and Hypercapnia
Authors: SYMON LINDSAY , HELD K. , DORSCH N. W. C.
Published: June 2011

Catheterization of Labbé's vein and of a pial branch of the middle cerebral artery has been performed on anesthetized baboons. Closure of the skull has enabled the reaction of the venous outflow from Labbé's vein to be monitored in response to pressure step increases in the pial arterial pressure induced by gas compression of a perfusion mixture connected to the arterial line. Rapid changes in cerebrovascular resistance with swift emergence of regulatory constancy have been shown, and the time characteristics of the resistance changes strongly suggest that they are primarily myogenic in origin. Induction of hypercapnia did not interfere with this autoregulatory mechanism to increased perfusion pressure, which indeed appeared to be more effective at raised arterial P
CO
2
, but the mechanism was abolished by the induction of ischemia from middle cerebral occlusion.
The Effect of Dexamethasone on the Edema of Focal Cerebral Ischemia
Authors: DONLEY ROBERT F. , SUNDT THORALF M.
Published: June 2011

The effect of large dosages of dexamethasone on the edema of cerebral ischemia and infarction in the squirrel monkey after temporary occlusion of the middle cerebral artery is reported. There was no difference between the ten monkeys treated with dexamethasone and the 11 control animals in clinical course, mortality, morbidity, histological appearance, or amount of edema associated with this ischemic lesion. The differences in the electron microscopic and pathophysiological findings of the edema from ischemia secondary to single major vessel occlusion and in the edema from an intracranial mass lesion are reviewed. The possible therapeutic or pharmacological effects of steroids are considered along with available data on lysosomes in the brain. At the present time, there is no justification for the use of large doses of dexamethasone in the treatment of cerebral infarction.
EKG Changes After Spinal Subarachnoid Hemorrhage
Authors: YARNELL PHILIP R. , GODFREY CLARK
Published: June 2011

Marked morphological electrocardiographical changes occurred in a patient whose subarachnoid hemorrhage originated in the lower spinal canal. Thus, the electrocardiogram can show the changes well known for intracranial subarachnoid hemorrhage even when the source of bleeding is in the lower spinal canal.
Plasma Renin Activity in Acute Cerebrovascular Disease: Preliminary Communication
Authors: MORAN JOHN H. , LOEWENSON RUTH B.
Published: June 2011

A preliminary study of plasma renin activity was made in 22 patients with acute cerebrovascular disease. Eight of 12 patients with intracranial hemorrhage had plasma renin activity values above the normal range of 30 to 330 ng/100 ml plasma, but only one of ten patients with ischemic cerebrovascular disease had increased plasma renin activity. The mean values for the two groups were, respectively, 489 and 190 ng/100 ml plasma (P for difference < 0.001). Ten days later plasma renin activity was normal in each of three patients with intracranial hemorrhage. The acute increase of plasma renin activity may have been associated with altered activity of the autonomic nervous system, and may be related to posthemorrhagic vascular events such as vasospasm.
Lactate in the Cerebrospinal Fluid and Pressure-Flow Relationships in Canine Cerebral Circulation
Authors: IWABUCHI TAKAYUKI , WATANABE KATSUHIRO , KUTSUZAWA TAKASHI , IKEDA KYUHEI , NAKAMURA TAKASHI
Published: June 2011

In 11 dogs, lactate and pH in the cerebrospinal fluid and in the arterial and the venous blood were measured during stepwise reductions of the arterial blood pressure by controlled bleeding. Increase in lactate and decrease in pH of the cerebrospinal fluid occurred with lowering of the mean arterial blood pressure even within the pressure ranges of 110 to 50 mm Hg, where autoregulation was fairly observed. Reductions of the blood pressure by 20 to 40 mm Hg led to a significant increase in lactate, and reductions by 60 mm Hg led to a significant decrease in pH of the cerebrospinal fluid.

The relation of decrease in pH and increase in lactate was linear, suggesting that lactacidosis occurred. In the arterial and the venous blood, a marked increase in lactate and decrease in pH also were observed. Lactate concentrations of the cerebral venous blood were significantly higher than those of the arterial blood until the arterial blood pressure had been reduced below 70 mm Hg. Therefore, it was suggested that increase in lactate of the cerebrospinal fluid might be attributed solely to increase in lactate of the brain tissue, so far as the blood pressure was not lowered below 70 mm Hg at least. The possibility of participation of the cerebrospinal fluid lactacidosis in autoregulation of the cerebral blood flow was discussed.
Stroke and Blood Coagulation
Authors: TODD MARGARET , MCDEVITT ELLEN , MCDOWELL FLETCHER
Published: June 2011

A study of the coagulation parameters of 87 normal controls (ages 50 to 80) were compared with those of 33 patients with thrombotic stroke and 55 patients with diabetes mellitus of the same age distribution.

There were no significant differences when tested for the influence of sex or age.

Twenty-seven tests of clotting were done on each specimen, a total of 4,725.

Significant differences were detected between normals versus patients with thrombotic stroke (fibrinogen level, glass clotting time, silicone clotting time, heparin tolerance, platelet count and retarded thromboplastin generation time BaSO
4
1:50 dilution) and between normals versus patients with diabetes (prothrombin time, silicone clotting time, platelet count, thromboplastin generation time and retarded thromboplastin generation time) when subjected to computer analysis. The clinical significance of these differences is not of practical value in the diagnosis or as a guide to therapy for stroke.
Clinical Indicators of Extracranial Carotid Artery Disease in Patients With Transient Symptoms
Authors: RAMIREZ-LASSEPAS MANUEL , SANDOK BURTON A. , BURTON ROBERT C.
Published: June 2011

The clinical findings in 64 patients with transient symptoms of unilateral carotid system ischemic disease (amaurosis fugax or transient focal cerebral ischemic attacks or both) were reviewed in an effort to determine the value of the neurovascular examination in predicting the presence and extent of roentgenographically demonstrated ipsilateral extracranial internal carotid artery disease. Amaurosis fugax seems to be a highly specific indicator of disease, being associated with 4% of normal vessels as compared to 27% for patients with transient focal cerebral ischemic attacks alone. In patients with transient symptoms, the incidence of a normal, ipsilateral carotid artery was 36% in the absence of any positive neurovascular findings, 15% in the presence of an ipsilateral carotid bruit, 6% in the presence of ipsilateral retinal embolic events, 5% in the presence of ipsilateral reduction in superficial temporal or carotid (or both) pulse, 4% in the presence of an ipsilateral reduction in retinal artery pressure, and 3% when more than one of these findings were noted. The neurovascular examination appears to be a useful adjunct in detecting the presence or absence of ipsilateral carotid disease. However, no combination of symptoms or signs would, in all cases, allow one to accurately determine whether a vessel was abnormal, stenotic, or occluded.
Cerebral Apoplexy (Stroke) Treated With or Without Prolonged Artificial Hyperventilation: 1. Cerebral Circulation, Clinical Course, and Cause of Death
Authors: CHRISTENSEN M. STIG , PAULSON OLAF B. , OLESEN JES , ALEXANDER S. CRAIGHEAD , SKINHØJ ERIK , DAM WILLY H. , LASSEN NEILS A.
Published: June 2011

Fifty patients with severe cerebral apoplexy were treated with artificial hyperventilation of three days' duration facilitated by general anesthesia (barbiturates and muscle relaxants) and instituted within the first day after onset of the attack. After a classification according to carotid angiographical findings, degree of consciousness and focal symptoms, a random allocation was performed so that 24 patients were subjected to moderate hypocapnia (Pa

CO

CO
2

about 25 mm Hg) and 26 patients to normocapnia (Pa

CO

CO
2

about 40 mm Hg). Afterward, 21 comparable patients not receiving ventilatory treatment were studied. The clinical course and the mortality rate showed no statistically significant differences between the three groups. All patients studied disclosed a longstanding (12 days) spontaneous hyperventilation.

The ventilation treatment was followed by a low cerebral perfusion pressure and a high rate of pulmonary complications. Autopsies from all groups studied typically showed tentorial herniation and pathological lung changes.

In 32 of the patients without occlusion of the carotid artery the regional cerebral blood flow was measured before hyperventilation treatment was applied. A low mean flow and focal abnormalities (ischemia, hyperemia, vasoparalysis) typically were found and in good correlation to the autopsy findings. In six of 13 patients tested an "inverse steal syndrome" following aminophylline was disclosed.
Prognosis in Patients with Transient Ischemic Attacks
Authors: ZIEGLER DEWEY K. , HASSANEIN RUTH STEPHENSON
Published: June 2011

The prognosis on 144 patients with transient ischemic attacks was determined over a minimum period of three years by quantitating, at intervals, the number of attacks and also the neurological disability by means of a disability score. No patients had neurological disability at the initiation of the study. Total cervicocephalic angiography was performed on 93 patients. Seven of the 144 patients were deceased at the end of the three-year period, five of them due to strokes. Seventeen patients (15.6%) developed persistent neurological disability during the three years, with the mean disability score being much higher for the patients with carotid attacks than those with basilar attacks. The cumulative number of attacks in both carotid and basilar groups rose steadily in the first 18 months, with a much larger number of attacks occurring in the basilar group. The attack rate leveled off after 18 months in the carotid group. Attacks tended to be consistent in nature over a period of time. Twenty-eight percent of those patients with basilar attacks and 12.5% of those patients with carotid attacks showed carotid stenosis on angiography. Study of carotid stenosis associated with subsequent neurological disability revealed that increased risk occurred only when carotid stenosis was more than 70%
Correlation of Continuous Electroencephalograms With Cerebral Blood Flow Measurements During Carotid Endarterectomy
Authors: SHARBROUGH FRANK W. , MESSICK JOSEPH M. , SUNDT THORALF M.
Published: June 2011

During an 11-month period, 81 endarterectomies under a carefully controlled level of general anesthesia were monitored with continuous electroencephalograms (EEG) and intermittent regional cerebral blood flow (CBF) measurements. There was a high correlation between the CBF (milliliter per 100 gm per minute) during carotid occlusion and alterations in the EEG: no EEG change was seen with the flow above 30 ml/100 gm brain per minute, major changes were not seen with a flow between 18 and 30 ml, and changes invariably occurred with a flow below 17 ml. The degree of EEG change reflected the severity of flow reduction but was always reversible with the placement of a shunt. The EEG at the termination of the surgery corresponded with the patient's neurological state in that all EEG tracings were normal or unchanged as compared to the preoperative tracing and no neurological worsening occurred in any patients studied. The EEG is a valuable monitoring technique that indicates when a shunt is required and informs the surgeon of the state of cerebral function not only during occlusion but also throughout the entire operative procedure.
Vascular Mechanisms Controlling a Constant Blood Supply to the Brain ("Autoregulation")
Authors: MCHEDLISHVILI GEORGE I. , MITAGVARIA NODAR P. , ORMOTSADZE LEILA G.
Published: June 2011

The segmental resistance in the major arteries of the brain and the respective smaller cerebral arteries carrying blood from the circle of Willis was computed (with a mathematical method developed recently) using the inlet and outlet pressures of the internal carotid arteries, as well as the venous pressure in the brain sinuses of dogs. Under the conditions of stepwise changes of the perfusion pressure the following localization of "autoregulatory" responses of the cerebral arteries has been found: changes in the inlet pressure of the internal carotid artery produced corresponding changes of its vascular resistance resulting in a relative constancy of the outlet pressure of the artery, i.e., pressure in the circle of Willis; resistance changes in the smaller brain arteries were evident only when the alterations of the perfusion pressure were too big and the major arteries were unable to eliminate the disturbance. The responses of the internal carotid arteries were eliminated when their muscular layer was maintained normal, but deprived of the nervous control (when the arteries were continuously perfused with blood or oxygenated Ringer-Krebs bicarbonate solution shortly after the death of the animal). Thus, evidence was obtained that the vascular responses were brought about by a nervous and not by a purely muscular mechanism, as is usually assumed.
Hypertension and Diabetes as Risk Factors in Stroke Patients
Authors: LAVY SYLVAN , MELAMED ELDAD , CAHANE ESTHER , CARMON AMIRAM
Published: June 2011

The occurrence of hypertension and diabetes in stroke patients was evaluated in a retrospective epidemiological study in the Jerusalem district. During the years 1960 through 1967, 1,522 new stroke cases (834 males and 688 females) were diagnosed and included in the study. Cerebral ischemia was diagnosed in 509 patients (33%), 181 patients (12%) had an intracerebral or subarachnoid hemorrhage and 832 patients (55%) had a stroke of undetermined type. For the total stroke series, 42% had hypertension. Almost the same percentage was found for males (41%) and females (43%). There was almost no sex predominance in the hypertensive stroke cases in the different age groups and for the various types of stroke. The frequency of hypertension among the stroke cases was low in the 40 to 49 age group, higher in the 50 to 59 age group, maximal in the 60 to 69 age group, and declining in the above 70 age group. The percentage of hypertensives was about the same for the ischemic and the undetermined types of stroke and for the total stroke series in the different age groups. It was found to be slightly higher in the hemorrhage type. The prevalence of hypertension among the male stroke cases was compared with the prevalence of hypertension in the general male population aged 40 and above (9.6%).

For the total stroke series, 20% had diabetes. The same percentage was found for males (19%) and females (20%). There was almost no sex predominance in the diabetic stroke cases in the different age groups and for the various types of stroke. There was no significant change in the distribution of diabetes in the various age groups and the different stroke types. The prevalence of diabetes among the male stroke cases was compared with its prevalence in the general male population aged 40 and above (5%).

Our study shows that hypertension and diabetes play an important role as risk factors in the development of cerebral ischemia and hemorrhage alike.
Report of Joint Committee for Stroke Facilities-- IX. Strokes in Children (Part 1)
Authors: GOLD ARNOLD P. , CHALLENOR YASOMA B. , GILLES FLOYD H. , HILAL SADEK P. , LEVITON ALAN , ROLLINS ELLEN I. , SOLOMON GAIL E. , STEIN BENNETT M.
Published: June 2011

The study group assigned the task of reviewing what is known about strokes in children has performed an outstanding service in bringing to the attention of readers of Guidelines for Stroke Care an important but little-publicized subject. They have given an analysis in depth, covering epidemiology, neuropathology, diagnosis and medical treatment, neurosurgical management, neuroradiology, rehabilitation, and psychological and educational problems. Strokes occur in children much less frequently than in the adult population. Nevertheless their significance should not be underestimated or underemphasized, for they have unusual features because their impact affects the developing nervous system.

The Strokes in Children section of the Report of the Joint Committee for Stroke Facilities is being published in two parts of which this is the first; the second part will appear in the November-December issue of this Journal.
Ulcerated Atheromatous Plaques of the Carotid Artery Bifurcation
Authors: GOMENSORO J. B. , MASLENIKOV V. , DE BONI J. A. , DE PEREZ G. LAGUARDIA , PURRIEL J. , MEDOC J. , BARRIOS R. RODRIGUEZ , ABO J. C. , TENYI A. , AZAMBUJA N.
Published: June 2011

The clinical diagnosis of an ulcerated plaque at the bifurcation of the common carotid artery is based on: mid-carotid bruit, cholesterol or platelet emboli in the retina, transient ischemic attacks particularly with amaurosis fugax, and a reversible neurological deficit.

In this series, thrombosis in situ was the final phenomenon in the natural history of the ulcerated plaque.

In certain unusual instances it appears that the pathogenesis of a transient ischemic attack is a decrease in cardiac output (fall in systemic blood pressure) leading to a disproportionate decrease in cerebral blood flow in that portion of the arterial system distal to a pathologically narrowed artery.

The ultimate diagnosis of an ulcerated plaque depends upon the radiological description at arteriography and upon direct visualization by the surgeon.

Surgical treatment at the present time is the therapy of choice.

Ulcerated carotid plaques may be bilateral, and, occasionally, are found at other levels than the bifurcation of the common carotid; however, ulcerated plaques were not seen in the intracranial vessels.
The Contribution of Nonaneurysmal Intracranial Hemorrhage to Stroke Mortality in New York City Blacks
Authors: SHAFER STEPHEN Q. , BRUUN BERTEL , RICHTER RALPH W.
Published: June 2011

Of 527 unselected stroke patients (98% black) in a city hospital, 80 (17%) had nonaneurysmal intracranial hemorrhages, with a fatality rate of 85%. Of 216 inhospital deaths 37% were due to such hemorrhages. In patients aged 65 and less, 52% of 90 fatal events were hemorrhagic. Only in patients below age 46, however, did cerebral hemorrhage account for more deaths than infarction. The incidence of hemorrhage and the proportion of inhospital deaths from it were higher than in three white American and lower than in one black African series. The differences were not major, and could be explained by varying definitions and hospital use. The mean age of patients with fatal hemorrhage was 61 years. When the inhospital mortality is extrapolated into annual mortality estimates, the following conclusions may be drawn about spontaneous nonaneurysmal intracranial hemorrhage in New York City blacks: (1) above age 45, it does not account for more deaths than infarction, (2) it is not much more common or more lethal in blacks than in whites, and (3) it does not occur more predominantly at earlier ages in blacks than in whites.
Neurological Manifestations of Infective Endocarditis: A Review
Authors: GREENLEE JOHN E. , MANDELL GERALD L.
Published: June 2011

Neurological complications are seen in patients with bacterial endocarditis and their incidence has not changed with the advent of antibiotics. Patients with abnormal neurological signs have a grave prognosis. Neurological sequelae of bacterial endocarditis are most often due to septic embolization producing ischemia and/or suppuration, resulting in infarction, hemorrhage, meningoencephalitis, or abscess. Clinical findings vary with the portion of the nervous system affected. The diagnosis should be suspected in the febrile patient with neurological signs of acute onset, the young patient with hemiplegia, the older patient with sudden changes in mentation, or the patient of any age with multifocal neurological signs. Diagnostic measures should include a careful history and physical examination, blood cultures and lumbar puncture where not contraindicated. Treatment is based on therapy of the bacterial endocarditis with bactericidal drugs, and therapy of intracerebral lesions with drugs that penetrate the blood-brain barrier. Consideration should be given to surgical intervention in mycotic aneurysms and brain abscesses.
The Relationship of Neurological Status and the Angiographical Evidence of Spasm to Prognosis in Patients With Ruptured Intracranial Saccular Aneurysms
Authors: HEILBRUN M. PETER
Published: June 2011

A retrospective analysis of 79 patients admitted to the Neurosurgery Department, Rigshospitalet, Copenhagen, Denmark, from January, 1969, through May, 1971, was performed. The clinical grading was performed according to a modification of the scheme of Hunt and Hess.
1
All patients were evaluated with angiography. Twenty-five of the 79 patients had preoperative angiographical evidence of spasm. Surgery was delayed for a mean period of 15 days in the majority of patients except for those with significant mass effects. Sixty-two of the 79 patients reached operation. Fortysix of the 62 patients had angiography performed immediately upon completion of surgery. Twenty-two of the 46 patients had angiographical evidence of spasm immediately postoperatively. The eventual outcome of all of the patients is evaluated according to the clinical grade and the presence of spasm preoperatively and postoperatively. The high incidence of spasm immediately after surgery shows that spasm is not a delayed phenomenon as is suggested by clinical evaluation. Methods for treating spasm should be started at the time of surgery.
Editorial
Authors: REINMUTH OSCAR M.
Published: June 2011

This prologue makes clear the factors that provided incentive for creating the Joint Committee for Stroke Facilities to prepare and publish the series of articles appearing regularly in
Stroke
(beginning with the May-June, 1972, issue), best described by the general title of Guidelines for Stroke Care. It points out in admirable fashion the many facets of the disease and will serve to acquaint the reader with the comprehensive nature of the subjects discussed in the "Guidelines."
The Effect of Sympathetic Denervation on Cerebral CO
2
Sensitivity
Authors: STONE H. L. , RAICHLE M. E. , HERNANDEZ M.
Published: June 2011

The responsiveness of cerebral blood flow to changes in arterial carbon dioxide tension was determined in six monkeys following bilateral superior cervical ganglionectomy. Experiments were conducted 10 to 14 days following the removal of both ganglions using phencyclidine hydrochloride as the anesthetic agent. Following the initial acute experiments, the animals were placed in a sealed environmental chamber for five days at an inspired carbon dioxide level of 6%. The responsiveness to carbon dioxide was repeated following the chronic exposure to carbon dioxide. The animal was killed immediately and the brain removed. The major vessels of the circle of Willis were examined histochemically for the presence of sympathetic nerve fibers. The results of the study demonstrated that: (1) autoregulation was still present, (2) acute exposure to increased levels of carbon dioxide increased flow, and (3) some adaptation of flow occurred following a chronic exposure to 6% carbon dioxide. The carbon dioxide sensitivity of this group of animals was found to be 0.37 cm per second mm Hg
-1
as compared to a value of 0.94 cm per second mm Hg
-1
for normal animals. The difference in these two values was significant. It is concluded that the sympathetic nervous system is necessary for the normal responsiveness to changes in arterial carbon dioxide.
The Veterans Administration Cooperative Study on Antihypertensive Agents. Implications for Stroke Prevention
Authors: FREIS EDWARD D.
Published: June 2011

Hypertension and atherosclerosis are the leading causes of stroke. The risk of stroke is directly related to the height of the blood pressure.

The Veterans Administration Cooperative Study included 523 male patients. If the results of two subgroups (115 to 129 mm Hg and 90 to 114 mm Hg initial diastolic) are combined, the total incidence of stroke was 25 in the control group and six in the treated group.

In addition to widespread lack of awareness of the medical profession of the benefits of treatment, there also is a failure of detection of hypertension in large segments of our population. There is need for greater professional as well as public education concerning hypertension.
Ineffectiveness of Dexamethasone for Treatment of Experimental Cerebral Infarction
Authors: LEE MYOUNG C. , MASTRI ANGELINE R. , WALTZ ARTHUR G. , LOEWENSON RUTH B.
Published: June 2011

Ischemic cerebral edema occurring with cerebral infarction may cause increases of intracranial pressure and neurological deficits or death. Certain other types of cerebral edema are influenced by adrenal glucocorticoids; there is conflicting evidence about effects on ischemic edema, largely due to differences in experimental models and dosages. Therefore, dexamethasone in large doses was studied in 15 cats with experimental cerebral ischemia and infarction produced by transorbital occlusion of one middle cerebral artery (MCA). Five cats received dexamethasone, 4 mg per kilogram intramuscularly, twice daily for two weeks before and two weeks after MCA occlusion; five received dexamethasone for two weeks after occlusion; and five received no dexamethasone. There were no apparent differences among the three groups in the neurological deficits resulting from MCA occlusion, and no statistically significant differences in the sizes of cerebral infarcts. Dexamethasone is ineffective for the treatment of experimental cerebral ischemia produced by MCA occlusion.
The Single Dye Passage. A New Technique for the Study of Cerebral Blood Flow Distribution
Authors: WEBER RAINER , FURUSE MASAHIRO , BROCK MARIO , DIETZ HERMANN
Published: June 2011

A method is described which permits studying regional blood flow distribution throughout a given organ by injecting a dye into one artery supplying said organ and inducing circulatory arrest during the dye injection.
High Blood Viscosity Syndrome in Cerebral Infarction
Authors: OTT ERWIN O. , LECHNER HELMUT , ARANIBAR ALBERTO
Published: June 2011

Determinations of whole blood viscosity by means of a cone plate viscometer at 37°C and at shear rates of 212, 42, 21 and 11 sec
-1
were done in 50 patients with recent cerebral infarction of the carotid system, and the values compared to a control group of 50 patients of the same age. In stroke patients a statistically significant elevation of blood viscosity over the whole range of shear rates was demonstrated, more obviously significant at low shear rates (P < 0.0001) such as occur in small vessels. Since the mean hematocrit levels of both groups were in the normal range, it was considered that hematocrit values estimated from peripheral blood do not necessarily give accurate information about viscosity levels existing at the same time.

In cases of severe cerebral infarction without angiographically demonstrable stenotic or obstructive lesions, it was suggested that high blood viscosity impairs hemodynamic conditions in the cerebral microvasculature in addition to narrow arteriosclerotic vessels, changes in flow velocity gradients and insufficient collateral circulation.
Measurement of Regional Cerebral Blood Flow With
133
Xenon and a Multiple-Crystal Scintillation Camera
Authors: CANNON P. J. , SCIACCA R. R. , BRUST J. C. M. , JOHNSON P. M. , HILAL S. K.
Published: June 2011

A method was devised to measure gray and white matter cerebral blood flow simultaneously in multiple regions of the brain using
133
Xenon and a multiple-crystal scintillation camera. Following magnification cerebral arteriography,
133
Xe was injected into the internal carotid artery and the washout of tracer was monitored with a scintillation camera which consists of 294 individually collimated NaI (TI) crystals. These data, obtained from each crystal overlying the brain, were processed by a weighted least-squares nonlinear regression technique. The blood flow rates of the rapid and slow compartments were calculated by the Kety-Schmidt formula along with 95% confidence limits for each measurement.

In four patients, local increases or decreases in regional cerebral flow were correlated with areas of pathology. In one patient with a cerebral arteriovenous malformation, regions of local shunting of tracer were identified. Application of a three-compartment analysis to these curves permitted estimation of the magnitude of shunting along with gray and white matter flow in the lesion. The increased discrimination provided by the multiple-crystal camera and the estimates of measurement accuracy obtained by this mathematical analysis may facilitate more precise localization of regional blood flow abnormalities in intracranial disease.
Editorial
Authors: ROSENBLUM WILLIAM I. , KONTOS HERMES A.
Published: June 2011

Micropuncture data suggest that pial arterioles contribute only slightly less than parenchymal cerebral arterioles to total resting cerebrovascular resistance. Care must be taken in interpreting the micropuncture data, or the contribution of pial arterioles to cerebrovascular resistance may be erroneously underestimated. These considerations and the fact that pial arterioles have been shown to be highly reactive to a variety of physiological and abnormal stimuli suggest strongly that changes in pial arteriolar diameter should contribute importantly to control of flow to the underlying brain. In fact, parallels between changes in pial vascular diameter and regional blood flow have been observed. Moreover, since the responses of pial vessels to important vasoactive stimuli are qualitatively similar to those of the cerebral circulation as a whole when the latter are inferred from measurements of flow, the directly observable pial vessels may provide a model for the responses of the unseen parenchymal segments of the cerebrovascular bed. Such a model would be essential to our understanding of the control of cerebral blood flow, even if pial vessels themselves did not participate in the control of flow. Thus there are multiple reasons for continued study of the pial vessels, particularly with modern techniques developed for microcirculatory investigations.
Effect of Methylprednisolone on Experimental Cerebral Infarction in the Mongolian Gerbil
Authors: MCGRAW C. PATRICK , FLEMING D. FRANK , SPRUIL JAMES H.
Published: June 2011

In a double-blind study, the effect of high doses of methylprednisolone on the cerebral edema induced by cerebral infarction was evaluated in 76 Mongolian gerbils. The incidence of experimentally induced cerebral infarction following carotid artery ligation is high in these animals because they lack a posterior communicating artery. One hour after the left common carotid artery had been ligated, 34 animals were given 30 mg per kilogram of the adrenocorticosteroid and the dose was repeated 24 and 48 hours later. Thirty-four animals were given normal saline on the same treatment schedule. Eight animals with sham operations were not treated. The animals were observed for ten days for signs of stroke. Surviving animals were killed on the tenth day and all brains were examined macroscopically and microscopically. Stroke developed in 41% of all animals; 31% died within ten days. Of the steroid-treated animals, stroke developed in 38% and 26% died. Of the saline-treated animals, stroke developed in 44% and 35.5% died. The differences were not significant by chi square analysis and the authors concluded that large doses of methylprednisolone given one hour after carotid ligation failed to prevent or influence the course of experimental stroke.
Adrenergic Mechanisms in Cerebral Blood Vessels: Effect of Tyramine on the Isolated Middle Cerebral Artery of the Goat
Authors: URQUILLA PEDRO R. , MARCO EMILIO J. , BALFAGON GLORIA , LLUCH SALVADOR
Published: June 2011

Tyramine induces dose-dependent changes in tension of the isolated middle cerebral artery of the goat. Cocaine, phentolamine and reserpine reduce the sensitivity of the tissue to tyramine by factors of 2.8, 3.7 and 3.7, respectively. The norepinephrine (NE) concentration of the arteries of the circle of Willis is 2.10 µg per gram and the corresponding value for the right atria is 1.25 µ per gram. Reserpine pretreatment (0.02 mg/kg/day for three days) reduces the NE concentration of the cerebral arteries to undetectable levels and that of the right atria to 2.4% of the control value. The relatively high concentration of NE of the cerebral arteries of the goat suggests that this tissue receives considerable sympathetic innervation. It is likely that part of the contractile response to tyramine is due to release of endogenous NE from sympathetic stores in the artery. However, some contractile response to tyramine remains after α-adrenergic blockade, reserpine pretreatment and in the presence of cocaine, suggesting that in addition to an indirect action (release of NE) tyramine also possesses a direct stimulatory effect in cerebral arteries.
Synaptic Alterations in Developing Cortical Infarction: An Experimental Investigation in Monkeys
Authors: LITTLE JOHN R. , KERR FREDERICK W. L. , SUNDT THORALF M.
Published: June 2011

The sequential synaptic alterations which occur during the early phase of developing cortical infarction in the squirrel monkey were studied with the electron microscope. Mild swelling of a few dendritic terminals and clumping of synaptic vesicles were the earliest detectable changes, being present at 45 minutes. The two basic patterns of degeneration of the terminal boutons were shrinkage and swelling, with shrinkage being the predominant response. Many of the shrunken boutons became electron-dense, resembling the changes present in anterograde axonal degeneration. The alterations which developed in the dendritic terminals were relatively unimpressive. Disruption of axosomatic synapses occurred at an earlier stage and was more severe than that of axodendritic synapses. Reduction in the number of synaptic vesicles was first observed at six hours and appeared to be progressive. The edema which developed was morphologically distinct from both "vasogenic" and "cytotoxic" edema in that there was early and progressive enlargement of the extracellular space.
Total Cerebral Blood Flow in the Monkey Measured by Hydrogen Clearance
Authors: MARTINS ALBERT N. , KOBRINE ARTHUR I. , DOYLE THOMAS F. , RAMIREZ ARCHIMEDES
Published: June 2011

Simple hydrogen-sensitive polarographical electrodes of thin platinum wire were inserted into the torcular Herophili of Rhesus monkeys. Hydrogen was administered by inhalation for ten minutes, after which the hydrogen clearance was recorded from torcular blood. At a Paco
2
of 32 mm Hg (SD ± 2.3), flow in the fast flow compartment was 102 ml/100 gm per minute (SD ± 19.1), and flow in the slow flow compartment was 28 ml/100 gm per minute (SD ± 5.8). Mean total cerebral blood flow was 52 ml/100 gm per minute (SD ± 10.5). Coefficient of variation was less than 10%.

Our experience suggests that one may reliably measure average total cerebral blood flow in the experimental setting by following the clearance of hydrogen from torcular blood. The method is relatively simple, inexpensive and radiation-free. It can be easily combined with the standard hydrogen clearance technique for measuring local tissue blood flow, thereby permitting the simultaneous recording of both local and total brain blood flow.
Vertebral Artery Occlusion Following Hyperextension and Rotation of the Head
Authors: OKAWARA S. , NIBBELINK D.
Published: June 2011

This is a case report of a lateral medullary syndrome of Wallenberg following occlusion of one vertebral artery and stenosis of the opposite artery precipitated by combined motion of hyperextension, rotation, and lateral flexion of the head within physiological limits. Sufficient duration of such head position appeared to initiate thrombus formation following stenosis or occlusion of the vertebral artery at the level of the atlanto-occipital joint. Propagation of this thrombus obstructed the posterior inferior cerebellar artery causing infarction of the lateral medullary region. The pathogenesis of this mechanism is discussed.
Myocardial Damage and Cardiac Arrhythmias After Intracranial Hemorrhage. A Critical Review
Authors: WEIDLER D. J.
Published: June 2011

Evidence is presented which supports the theory that intracranial hemorrhage may secondarily cause myocardial damage and cardiac arrhythmias.

Fatal intracranial hemorrhage occasionally is accompanied by ECG changes which are consistent with myocardial infarction; histological examination of the heart revealed a variable amount of myocardial damage. After intracranial hemorrhage in animals, myocardial damage was frequent. Similar myocardial damage was produced in animals by intravenous infusion of norepinephrine or acetylcholine and by electrical stimulation of the stellate ganglia, vagus nerve or mesencephalic reticular formation.

Atrial and ventricular arrhythmias and various degrees of A-V block were reported in patients suffering from subarachnoid hemorrhage. Similar cardiac arrhythmias were found in animals after intracranial hemorrhage, and with electrical stimulation of the vagus nerve, stellate ganglia or CNS centers. Available data suggest that increased or altered autonomic activity may be the mechanism whereby intracranial hemorrhage produces myocardial damage and cardiac arrhythmias.

The efficacy of autonomic blockade in preventing myocardial damage, which was secondary to experimental intracranial hemorrhage in animals, was demonstrated. It is suggested that the initiation of therapy with autonomic blocking drugs, as soon as possible after the onset of intracranial hemorrhage in patients, may be useful in preventing myocardial damage and cardiac arrhythmias.
Scanning Electron Microscopic Observations on the Luminal Surface of the Rabbit Common Carotid Artery Sublected to lschemia by Arterial Occlusion
Authors: KAWAMURA JUNICHIRO , GERTZ S. DAVID , SUNAGA TOSHIAKI , RENNELS MARSHALL L. , NELSON ERLAND
Published: June 2011

The scanning electron microscope (SEM) has been employed to study the effects of ischemia on the luminal surface of the common carotid artery. Fifteen adult rabbits were lightly anesthetized and the common carotid arteries surgically exposed. The right carotid artery was occluded with a single Heifetz clip for five minutes (five animals), 15 minutes (five animals), and 30 minutes (five animals). Following removal of the clip, the animals were immediately perfused with glutaraldehyde and the arteries excised and prepared for critical point drying. Four additional rabbits were perfused following the same method with no surgical procedures performed in the neck. Normal aortas were also examined. The nature and frequency of endothelial cell alterations were determined by analysis of ten randomly selected SEM fields. Examination of the endothelial surface of arterial segments distal to the occluding clip revealed the presence of numerous "crater-like" defects as well as outpouchings or "balloons." The numbers of craters and balloons were significantly increased in the ischemic (distal) arterial segment as compared to either proximal or sham-operated control segments (P < 0.001). These endothelial cell alterations were never observed in random micrographs of arterial segments taken from unoperated control animals, but were seen at the ostia of some intercostal arteries of the aorta. It is suggested that these craters and balloons could cause interference with blood flow and the for mation of platelet thrombi by their protrusion into the lumen, as well as alteration of the permeability of the arterial intima.
Global Ischemia in Dogs: Intracranial Pressures, Brain Blood Flow and Metabolism
Authors: SNYDER JAMES V. , NEMOTO EDWIN M. , CARROLL ROBERT G. , SAFAR PETER
Published: June 2011

Our earlier studies showed no secondary postischemic (PI) rise in cisterna magna pressure (CMP) for ten hours and no significant reduction in CBF (integrated N
2
O desaturation technique) for three and one-half hours after 15 minutes of systemic circulatory arrest. However, transtentorial pressure gradients may have developed, and CBF changes may have been masked by limitations of the N
2
O method in low flow states. In this study, 12 dogs were subjected to 15 minutes of aortic occlusion and studied for two hours PI. Immediately after restoration of circulation, cisterna magna, supracortical and lateral ventricle pressures rose to 35 to 40 torr, concomitant with a threefold increase in cerebral blood flow (
133
Xe clearance technique). By 30 minutes postischemia, cisterna magna and supracortical pressures had returned to control values but lateral ventricular pressures normalized slower. CBF decreased to and remained at 50% of preischemic values after 40 minutes PI. Cerebral glucose uptake increased markedly immediately PI, then fell significantly below control values at 45 minutes. Cerebral O
2
uptake was significantly reduced, although less than for glucose, between 30 and 60 minutes PI. Global ischemia for 15 minutes is followed neither by a secondary rise in intracranial pressure nor by a cerebrospinal fluid pressure gradient but rather by hypoperfusion and defective glucose metabolism.
Barbiturate Protection From Cerebral Infarction in Primates
Authors: HOFF JULIAN T. , SMITH ALLAN L. , HANKINSON f HAL L. , NIELSEN SURL L.
Published: June 2011

Baboons were anesthetized with halothane or pentobarbital prior to middle cerebral artery (MCA) occlusion to test the protective effect of barbiturates against stroke in primates. Significantly less infarction was found in animals that received 90 mg per kilogram pentobarbital or more than occurred in control animals. Because of cardiovascular and ventilatory complications at high doses of barbiturate, however, therapeutic trials to suppress stroke in the human must await further identification of an effective regimen which includes a safe barbiturate dose.
Regional Cerebral Blood Flow by
133
Xenon Inhalation
Authors: RISBERG JARL , ALI ZENAB , WILSON EDWIN M. , WILLS EDWARD L. , HALSEY JAMES H.
Published: June 2011

Repeated measurements of regional cerebral blood flow (rCBF) were made by the short (ten minutes)
133
Xenon inhalation technique and bicompartmental analysis in 11 patients with cerebrovascular disorders, mainly acute cerebral infarction. rCBF was measured 3 to 11 times during one to two weeks. The blood flow of the fast compartment (f
1
) was calculated as well as the relative weight of this compartment (w
1
, assumed to correspond to gray matter). In addition a new flow index, the Initial Slope Index (ISI) modified for the inhalation technique, was used. This index of predominantly gray matter flow was calculated from a one-minute epoch of the early part of the clearance curve corrected for recirculation. In three of the patients the f
1
and ISI varied in parallel and the w
1
showed generally only minor variations from one measurement to the other. However, in the other eight patients fluctuation of the w
1
and f
1
values were seen which often showed no meaningful relation to the clinical course. The observed w
1
changes indicated that some tissues (slowly perfused gray matter and/or rapidly perfused white extracerebral tissues) fluctuate between the fast and the slow compartment. In such cases the f
1
values obtained cannot be used for comparison between measurements, since they represent flow rates of varying tissues and do not always represent a true gray matter blood flow. In these patients the ISI, which is independent of such weight changes, showed moderate and clinically likely variations.
Disordered Cholinergic Neurotransmission and Dysautoregulation After Acute Cerebral Infarction
Authors: OTT ERWIN O. , ABRAHAM JACOB , MEYER JOHN STIRLING , ACHARI AMRIT N. , CHEE ANTHONY N. C. , MATHEW NINAN T.
Published: June 2011

The possible role of displaced neurotransmitter acetylcholine (ACh) in dysautoregulation was examined after experimental regional cerebral infarction was produced by occluding the middle cerebral artery (MCA) in baboons. Regional cerebral blood flow (rCBF) was measured after intracarotid injection of
133
Xenon using the gamma camera. Autoregulation was tested with metaraminol or angiotensin infusion and the autoregulation index (A.I.) was calculated. Acetylcholinesterase (AChE) was measured in brain tissue of noninfarcted and infarcted hemispheres. Cerebral arteriovenous (A-V) differences for cholinesterase (ChE) were also measured. Regional dysautoregulation was found in infarcted gray matter and correlated with increased AChE levels in the same zones of cortex and basal ganglia. The time course of onset of dysautoregulation correlated with increased ChE uptake by the brain. Intravenous infusion of the cholinergic neurotransmitter blocker, scopolamine, restored autoregulation to the ischemic zones. Autoregulation appears to be a myogenic reflex, influenced by neurogenic and metabolic mechanisms.
Cerebral Blood Flow in Cats After an Acute Hypertensive Insult With Damage to the Blood-Brain Barrier
Authors: PANNIER J. L. , LEUSEN I.
Published: June 2011

Cerebral blood flow was measured with the
133
Xenon clearance method in anesthetized cats under controlled ventilation. An acute pressure increase in the carotid system increases the cerebrovascular permeability to Evans blue, indicating damage to the blood-brain barrier. In these conditions the reactivity of cerebral blood vessels toward changes in the acid-base balance is altered: the CO
2
reactivity is less pronounced, while the effect of increasing the plasma [HCO
-
3
] is more pronounced than in normal cats. Autoregulatory capacity toward moderate alterations in arterial blood pressure or in intracranial pressure is well maintained in these conditions.
Carotid Compression Tonography
Authors: COHEN DAVID N. , WANGELIN RICHARD , TROTTA CARLOS , BEVEN EDWIN G. , HUMPHRIES ALFRED W. , YOUNG JESS R.
Published: June 2011

One hundred twenty-two patients had carotid compression tonography (CCT) followed by bilateral carotid arteriography. In the group (82 patients) which was felt to have significant occlusive disease of the internal carotid at the level of the carotid bifurcation (>50% stenosis), the CCT showed a 92% correlation with arteriography. Of the group (48 patients) that underwent endarterectomy, there was a 94% correlation with CCT testing. In 40 patients, with normal arteriograms or with less than 50% stenotic lesions on arteriography, there was a large number (25%) of patients with a CCT test which appeared to indicate decreased flow. Various reasons for this are discussed.

The high correlation of the CCT test and carotid arteriography in the patients with surgically amenable lesions would suggest that the CCT test is a good noninvasive screening technique for the detection of significant occlusive disease of the extracranial carotid vascular system.