bluuebunny/crossref_metadata_2025 huggingface dataset:
Risk Factors in Stroke: A Clinical Study in Mexican Patients
Authors: OLIVARES L. , CASTAÑEDA E. , GRIFÉ A. , ALTER M.
Published: June 2011

Mexicans hospitalized between July, 1967, and June, 1968, with clinically diagnosed stroke provided information on risk factors in a population from which little systematically collected information on stroke exists. The patients were beneficiaries of ISSSTE, a government-sponsored health care system. Postmortem examination in 20 patients indicated virtually 100% validity of diagnosis. Cerebral thrombosis, hemorrhage and embolus occurred in a ratio of 6:2:1. There was no sex difference in stroke frequency. Thrombosis and hemorrhage increased with age; embolus occurred more often in younger patients. Thrombosis tended to occur when at repose and in individuals with sedentary occupations; the opposite was found with hemorrhage and embolus. Obesity did not seem to predispose to stroke. Hypertension, heart disease and diabetes mellitus emerged as common antecedent conditions. There was a morning peak in onset of thrombosis and hemorrhage and an afternoon peak for embolus. No relation of onset to holidays or stress was noted. Thrombosis, hemorrhage and embolus all were associated with increased ambient temperature, and with low, slightly decreased and high humidity, respectively. An August-September (end of rainy season) peak in seasonal frequency occurred. The risk factors previously identified as being important mainly in northern populations seemed to be important in this Mexican population as well. Thus, ethnic and cultural variability exerted little effect on stroke frequency.
Regional Cerebral Blood Flow Determination by the Hydrogen Clearance Technique and Comparison With Oxygen Availability in the Rabbit
Authors: JAMIESON ANDREW D. , HALSEY JAMES H.
Published: June 2011

Hydrogen clearance using the tissue polarographical electrode appears to be a potentially useful technique for intermittent measurements of rCBF in relatively small areas. Both chronic and acutely implanted electrodes were placed at different depths in rabbit cerebrum including cortex and subcortical gray and white matter. Polarographical electrodes, oppositely charged, sensing oxygen availability (O
2
a) also were implanted proximately for comparison of both rCBF response and O
2
a under conditions of normocapnia and hypercapnia. No functional difference was discerned between chronic and acute electrodes. Generally rates of blood flow were faster in gray matter than in white. Both monoexponential and biexponential curves, representing one and two compartments of blood flow, respectively, were observed in both gray and white matter. Some three-compartment curves also were seen. Hypercapnia generally induced faster rCBF in all compartments as well as increased O
2
a. Occasionally a change in compartmentalization was recorded from a single electrode during hypercapnia, and two instances of paradoxical decrease in rCBF were observed. A multicompartmental model with an arteriovenous thoroughfare shunt was postulated to account for the wide range of blood flow values recorded: from 5.2+ to 0.2 ml per gram per minute.
Massive Brain Hemorrhage: A Review of 144 Cases and an Examination of Their Causes
Authors: McCORMICK WILLIAMS F. , ROSENFIELD DAVID B.
Published: June 2011

A detailed clinicopathological study of the causes and locations of massive nontraumatic brain hemorrhage in 144 patients is reported. A cause of the hemorrhage, such as an aneurysm, angioma, arteritis, neoplasm or a blood dyscrasia (leukemia, hemophilia), was proved in two-thirds (95) of these patients. Twelve normotensive patients had no cause found to explain their hemorrhage. Systemic hypertension, generally mild, defined as a pre-ictal pressure of > 140/90 or by excessive heart weight, was present in 58 of the 144 patients. Twenty-one of these 58 hypertensive patients had a clear discernible cause for their brain hemorrhage (i.e., leukemia, metastatic carcinoma, angioma, aneurysm), whereas no satisfactory morphological cause could be found in only 37. Thus, in only about one-fourth of our patients could any serious claim be made that hypertension was the cause of the hemorrhage. Our data would indicate the need for a critical study of the causes of intracranial hemorrhages, and re-evaluation of the true relationship of systemic hypertension to such strokes. The widespread dogma that hypertension is the outstanding cause of nontraumatic brain hemorrhage no longer seems warranted.
Transient Ischemic Attacks and Risk of Stroke in an Elderly Poor Population
Authors: OSTFELD A. M. , SHEKELLE R. B. , KLAWANS H. L.
Published: June 2011

The significance for stroke and correlates of transient ischemic attacks (TIA) were studied prospectively in a population of 2,772 persons aged 65 to 74. The prevalence of TIA at the beginning of the study was 63 per 1,000. TIA prevalence was substantially higher among blacks and women than among whites and men. Only 13% of those with TIA were free from any other major evidence of cardiovascular disease. White men, black men and black women with TIA had higher observed incidence rates of stroke than those without TIA. White women were a notable exception to this trend. There was a positive association between frequency of TIA and risk of stroke. Those with TIA and hypertension experienced higher stroke incidence rates than normotensive persons with TIA.
The Value of Regional Cerebral Blood Flow Measurements Compared to Angiography in the Assessment of Obstructive Neck Vessel Disease
Authors: PROSENZ P. , HEISS W.-D. , TSCHABITSCHER H. , EHRMANN L.
Published: June 2011

In 50 patients with internal carotid artery occlusion and 40 patients with internal carotid artery stenosis hemispheric and regional cerebral blood flow (rCBF) was measured by the
133
Xenon clearance method, rCBF was evaluated according to the presence of ischemic or hyperemic foci and to the level of regional perfusion alteration. The degree of collateral circula tion and diameter of stenosis were determined from the angiograms. The clinical symptoms were expressed in a score of motor deficiencies. In internal carotid artery occlusion no correla tion of motor deficiency index with angiographically demonstrable collateral circulation was detectable, but there was good correlation with hemispheric CBF and an excellent correlation (P < 0.001) with the rCBF parameters. In internal carotid artery stenosis no correlation existed between motor deficiency and the degree of stenosis or hemispheric CBF, but good correlation was observed between motor deficiency and the rCBF parameters (P < 0.01).

According to these findings, angiographical demonstration of collateral circulation and of stenosis does not provide as accurate information on impending or already developed tissue in farction as does rCBF measurement. Presence of hyperemic foci and lack of ischemic foci were related to lesser motor disturbances. Borderlines of 30 ml/100 gm per minute for threatening tissue ischemia and of 25 ml/100 gm per minute for present tissue ischemia are established. Some points favor the thromboembolic theory of infarction in internal carotid artery stenosis.
Comparison of Care and Cost Outcomes for Stroke Patients With and Without Home Care
Authors: BRYANT NANCY H. , CANDLAND LOUISE , LOEWENSTEIN REGINA
Published: June 2011

This study was undertaken to compare care and cost outcomes of stroke patients who received home care with those who did not receive home care at St. Luke's Hospital Medical Center, New York, New York.

Twenty-five home care stroke patients were matched by age and sex with 25 comparable stroke patients receiving no home care during 1971.

After nine months' follow-up, stroke patients who received home care had shorter hospital stays (average, ten days less), overall costs greatly reduced (average, $3,450 for home care patients versus $8,300 for comparison group), fewer readmissions for recurring strokes, and fewer deaths (two versus nine). At the end of nine months, home care patients were located as follows: 20 at home, two on home care, one in a nursing home, and two were dead. The comparison group showed: eight at home, one at an extended-care facility, seven in nursing homes, and nine were dead. The differences in care and cost outcomes between these two groups have considerable implications for patients, hospitals, physicians, and third party payers.
The Effects of lodinated Contrast Agents on Autoregulation of Cerebral Blood Flow
Authors: GRUBB ROBERT L. , HERNANDEZ-PERIZ MILTON J. , RAICHLE MARCUS E. , PHELPS MICHAEL E.
Published: June 2011

The effects of an iodinated contrast agent, Renografin-76® upon cerebral autoregulation was studied in rhesus monkeys. This was done by measuring the effects of an intravenous injection of Renografin-76 upon: (1) the response of baseline CBF as measured by the washout of a carotid bolus of H
2
15
O during and after the injection of Renografin-76, (2) the response of CBF monitored continuously by a Doppler flow probe technique to changes in the mean arterial blood pressure (MABP) before and after an injection of Renografin-76, and (3) the response of the regional cerebral blood volume (rCBV) as measured by stimulated x-ray fluorescence. An intravenous injection of Renografin-76 can disturb cerebral autoregulation in the rhesus monkey for as long as 15 minutes after the beginning of the injection. After the intravenous in jection of Renografin-76, transient rises in both CBF and MABP lasting from 2 to 12 minutes occurred on an average of 23% and 16%, respectively, over control values.
Effects of Beta-Adrenergic Blockade on Cerebral Autoregulation and Chemical Vasomotor Control in Patients With Stroke
Authors: STIRLING JOHN , OKAMOTO SHIGEMICHI , SARI ATSUO , KOTO ATSUO , ITOH YOSHIFUMI , ERICSSON ARTHUR DALE
Published: June 2011

Autoregulation and chemical vasomotor control of cerebral blood flow (CBF) were measured in 14 patients with cerebral ischemia and infarction classified according to severity and anatomical location before and after intracarotid injection of the beta-adrenergic blocking agent, propranolol hydrochloride (PPL). Intracarotid injection of 1.45 µg per kilogram body weight per minute of PPL (average total dose 2 mg) was followed by a reduction in CBF and oxygen consumption and an increase of cerebrovascular resistance. Mean arterial blood pressure, intracranial venous pressure, and cerebrospinal fluid pressure were unchanged. Cerebral autoregulation was tested by raising and lowering cerebral perfusion pressure (CPP) by the use of a tilt-table. Chemical vasomotor control of CBF was tested by inhalation of 7% CO
2
+ air and voluntary hyperventilation. Following the injection of PPL, cerebrovascular resistance was significantly increased when autoregulation was tested by raising CPP. The autoregulation index decreased significantly during the head-down position and tended to increase during the head-up position, but the latter trend did not reach the level of statistical significance. The chemical regulation index was not altered by propranolol during changes of Pa

co
co2

.

These results support the view that beta-adrenergic innervation influences cerebral metabolism as well as exerting a tonic cerebral vasodilator tonus. Hence, intracarotid injection of PPL blocks the beta-adrenergic dilator tonus and CBF and oxidative metabolism decrease. Likewise, the ability of cerebral vessels to constrict is improved when CPP is increased since cerebral vasoconstrictor tonus is enhanced. When CPP is lowered, cerebral autoregulation is unchanged or worsens. Chemical regulation of CBF to changes in Pa

co
co2

, is unchanged by beta blockade.
Oxygen Cycles and Metabolic Autoregulation
Authors: HALSEY JAMES H. , MCFARLAND SCOTT
Published: June 2011

Rhythmical three to eight per minute cycles in oxygen availability are characteristic of recordings from chronically implanted open tip polarographic electrodes. These were demonstrated to be progressively decreased in amplitude as mean arterial blood pressure was raised from 75 mm Hg to 160 mm Hg, at which level they were abolished. Amplitude of these :ycles also decreased as BP was reduced below 75 mm Hg and they again disappeared at an iverage of 60 mm Hg. Oscillation frequency appeared to be a function of rate of metabolism, oeing reduced by anesthesia, hypothermia, and ischemia. An hypothesis is proposed which relates these oscillations to the feedback delay between metabolic generation of CO
2
and the appropriate adjustment in tension of the pH sensitive muscle of the precapillary arteriole which in turn determines rate of local CO
2
clearance. The changes in amplitude of the oxygen cycles may indicate alteration in pH reactivity of precapillary smooth muscle as a function of BP.
The Influence of Nonrespiratory Alkalosis on Cerebral Blood Flow in Cats
Authors: PANNIER J. L. , DEMEESTER G. , LEUSEN I.
Published: June 2011

Cerebral blood flow was measured with the
133
Xenon clearance method during short-lasting (20 minutes) and more prolonged (90 minutes) infusions of Na
2
CO
3
solutions in anesthetized cats under controlled ventilation. The infusion protocol was regulated so as to produce a given increase in the plasma [HCO
3
-
] in the first 15 minutes, followed by a constant high plasma level for the rest of the infusion period. A high Pa
co
3
level was induced before and at the end of the infusion, when prolonged infusions were made. The results indicate that, in acute experiments (20 minutes), an increase in plasma [HCO
3
-
] of 14 mEq/l does not influence CBF. During more prolonged infusions (90 minutes), an increase of 12 mEq/l produces a reduction of CBF and an increase in the CSF [HCO
3
-
]. These changes are more pronounced when the increase in plasma [HCO
3
-
] is more marked (18 mEq/l).
Segmented Middle Cerebral Artery Occlusion in Primates: An Experimental Method Requiring Minimal Surgery and Anesthesia
Authors: MOLINARI G. F. , MOSELEY J. I. , LAURENT J. P.
Published: June 2011

Due to certain anthropomorphic features of the cerebral circulation, monkeys are generally preferable to lower species in experimental models of stroke. By injecting specially molded silicone cylinders through internal carotid artery cannulas, segmental occlusions of the middle cerebral artery were produced in macaques. This embolic method produced cerebral infarction in all instances while the integrity of skull and intracranial collateral circulation were preserved. Because only neck surgery was required, local anesthesia could be used, permitting observation of acute infarctions in sedated, conscious animals.
The Effect of Carbon Dioxide Inhalation on Cerebral Blood Flow: A Two-Hour Duration Study in Dogs With Microspheres
Authors: JACKSON RICHARD T. , CLAIRMONT ALBERT A. , POLLOCK RICHARD A.
Published: June 2011

Dogs breathed one of four gas mixtures (5% CO
2
-95% O
2
, 5% CO
2
-95% air, 10% CO
2
-90% O
2
, and 10% CO
2
-90% air) for as long as two hours. Regional cerebral blood flow as well as flow in nasal, otic, pituitary and skin tissue were measured by means of 15 ± 5 µ radioactively labeled microspheres. The normal values for cerebral blood flow and arterial blood gases were very similar to those of other investigators. Inhalation of CO
2
induced an increase in cerebral blood flow that was significantly higher than is usually reported. Increases varied from 100% (with 5% CO
2
-95% air) to 250% (with 10% CO
2
-90% O
2
). Blood flow in the temporal bone behaved much like that of brain in response to CO
2
. In most instances, the pituitary gland blood flow did not increase with inhalation of CO
2
.
Family Strock Education
Authors: WELLS ROE
Published: June 2011

An educational program for family members of patients experiencing a recent stroke is described. The educational sessions involve all members of the rehabilitation team in a round table discussion as well as a question and answer format. Surveys of family members indicate this educational process resulted in a decreased anxiety about stroke, improved communications with the staff and a more supportive role in the therapy of the patient. The group sessions also reduce the inefficiency of each staff member explaining his or her role on an individual basis.
Personality Patterns and Life Stress in lschemic Cerebrovascular Disease
Authors: GIANTURCO D. T. , BRESLIN M. S. , HEYMAN A. , GENTRY W. D. , JENKINS C. D. , KAPLAN B.
Published: June 2011

The personality, life stress and affect at onset of illness of white men hospitalized for transient cerebral ischemia and cerebral infarction were compared with those of control subjects admitted to the hospital for acute nonvascular illnesses. A "pressure pattern" of behavior characterized by aggressiveness, ambition and striving for achievement appeared to be the predominant personality feature among patients with cerebrovascular disease who had a history of myocardial infarction or angina pectoris. There was also some evidence that an unpleasant affective state prior to the onset of stroke occurred more frequently in men with combined coronary and cerebrovascular disease than in those without such a history or in control subjects. No relationship was found between personality features and attributes such as hypertension, age, cigarette smoking or education. These findings suggest that certain behavioral features in patients with coronary heart disease should be considered as risk factors in the development of cerebral ischemia or infarction.
Acute Canine Cerebral lschemia: A Preliminary Model to Evaluate Microvascular Mammary-Carotid Anastomosis
Authors: OSGOOD CARROLL P. , DUJOVNY MANUEL , WISOTZKEY HOWARD
Published: June 2011

Although the dog remains the standard surgical laboratory animal, its extensive collateral circulation makes complete interruption of cerebral blood flow quite difficult. A simple yet reliable canine model for the study of cerebrovascular insufficiency would seem desirable. We have found that complete division of the left subclavian and right brachiocephalic arteries and their major branches can be rapidly performed through a small left thoracotomy. This interruption of blood supply is incompatible with resumption of normal respiratory function, consciousness, or survival, and can be used to evaluate extra-anatomic grafts or anastomoses.
Cigarette Smoking and Strokes
Authors: NOMURA ABRAHAM , COMSTOCK GEORGE W. , KULLER LEWIS , TONASCIA JAMES A.
Published: June 2011

Utilizing a defined general population, two investigations were conducted in Washington County, Maryland. In the eight-year mortality study, the relative risk of stroke among cigarette smokers was only 0.85 as compared to nonsmokers. In the two-year morbidity investigation, limited to stroke cases occurring after the age of 50, it appears that the association of cigarette smoking to strokes in the older age groups is at most very small.

In atherosclerotic strokes, there may be an association with cigarette smoking, but only in the younger age groups, as suggested by two other studies. In order to investigate this possibility a retrospective case/control study of young cases is recommended. If there is no age dependency of atherosclerotic strokes, this implies that cigarette smoking may not be associated with the atherosclerotic process in cerebral and coronary arteries.
COOPERATIVE STUDY OF INTRACRANIAL ANEURYSMS AND SUBARACHNOID HEMORRHAGE Report on a Randomized Treatment Study
Authors: GRAF CARL J. , NIBBELINK DONALD W.
Published: June 2011

A group of 274 patients with a single intracranial aneurysm was randomly allocated to intracranial surgery. Forty patients had no surgical procedure. Only six had a vertebral-basilar aneurysm. The remaining 228 patients had an aneurysm on the anterior portion of the circle of Willis. Mortality during the six and one-half-year interval was 36.8%. When the operation was performed within 14 days following the last bleed, mortality was 44.5%; for those operated upon after the 14-day interval mortality was 23.2%. Postoperative complications occurred in 47.8%.
Headache and Transient Ischemic Attacks
Authors: GRINDAL ALAN B. , TOOLE JAMES F.
Published: June 2011

Headache occurring in association with episodes of transient cerebral ischemia has not been emphasized as part of the symptom complex.

In an effort to ascertain the frequency and characteristics of these headaches and to determine whether there is any localizing, diagnostic, or prognostic significance to them, the records of 240 TIA patients were reviewed.

We concluded that headache is a prominent symptom in 25% of patients with TIA and that there were no distinguishing population characteristics, arteriographical findings or prognostic features among patients whose TIAs were accompanied by headache. The locations and temporal relationships of headache occurring in cases of carotid and vertebrobasilar TIA also were compared.
Effects of Dexamethasone on Distributions of Water and Pertechnetate in Brains of Cats After Middle Cerebral Artery Occlusion
Authors: HOPPE WAYNE E. , WALTZ ARTHUR G. , JORDAN MARGARET M. , JACOBSON RONALD L.
Published: June 2011

Large parenteral doses of dexamethasone were given to five of ten cats after transorbital occlusion of one middle cerebral artery and to two of four cats after sham operations. Two days later the water content and brain/blood ratios of pertechnetate were measured in samples of cerebral tissue that were categorized as nonischemic, ischemic, or infarcted. Values for infarcted tissue were greater than those for ischemic tissue in untreated cats, but not in cats that received dexamethasone. The drug had no apparent effect in ischemic tissue that was not necrotic. These results help explain inconsistencies in previous studies and help define the potential usefulness of dexamethasone for treatment of cerebrovascular disease.
The Effects of Changes in Pa
CO
2
Cerebral Blood Volume, Blood Flow, and Vascular Mean Transit Time
Authors: GRUBB ROBERT L. , RAICHLE MARCUS E. , EICHLING JOHN O. , TER-POGOSSIAN MICHEL M.
Published: June 2011

The relationships between cerebral blood volume (CBV), cerebral blood flow (CBF), and the cerebral vascular mean transit time (t
v
) during acute changes in the Pa
CO
2
over a range of 15 to 76 torr were investigated in vivo in rhesus monkeys by serially determining the mean transit time of a vascular tracer,
15
O-labeled carboxyhemoglobin, and the mean transit time of a diffusible tracer,
15
O-labeled water. Over this range of Pa
CO
2
, a significant linear relationship of CBV = 0.041 Pa
CO
2
+ 2.0 was found. For each one torr change in Pa
CO
2
, there is a change in CBV of 0.041 ml/100 gm of perfused tissue. At a normocarbic value of Pa
CO
2
(37 torr), an average value of 3.5 ml/100 gm was found. A nonlinear relationship of CBV and CBF was found. This relationship is expressed in the equation, CBV = 0.80 CBF
0.38
. A significant linear relationship was found between CBF and Pa
CO
2
. This was described by the equation, CBF = 1.8 Pa
CO
2
- 16.75. For each one torr change in the PaCO
2
, there is a 1.8 ml/100 gm per minute change in the CBF. At a normocarbic value of Pa
CO
2
(37 torr), an average value of CBF of 50 ml/100 gm per minute was found. The relationship of CBV and t
v
was nonlinear and was expressed in the equation, t
C15O
= 41 CBF
-0.62
.
Asymptomatic Occlusion of an Internal Carotid Artery in a Hospital Population: Determined by Directional Doppler Ophthalmosonometry
Authors: DYKEN MARK L. , DOEPKER J. FREDERICK , KIOVSKY RICHARD , CAMPBELL ROBERT L.
Published: June 2011

Reversal of blood flow in an ophthalmic artery as determined by directional Doppler ultrasound (OSM) was present in nine (3%) of 310 patients over 50 years of age who did not have complaints, diagnoses or examination findings suggesting disease of the central nervous system, and was present in nine (12%) of 73 patients with neurological disease selected as technical controls. Twenty-two of the control patients had four-vessel angiography. Five with OSM evidence of reversal of flow had functional occlusion of the appropriate internal carotid artery, and 17 without reversal did not. This study presents evidence that occlusion of an internal carotid artery frequently occurs without producing recognizable clinical dysfunction.
Interrelationships Among Regional Cerebral Blood Flow, Mean Transit Time, Vascular Volume and Cerebral Vascular Resistance
Authors: KURIYAMA YOSHIHIRO , AOYAMA TAKASHI , TADA KUNIHIKO , YONEDA SHOTARO , NUKADA TADAATSU , ABE HIROSHI
Published: June 2011

The simultaneous measurement of regional cerebral blood flow (rCBF), mean transit time (MTT), vascular volume (CVV) and cerebral vascular resistance (CVR) was performed in patients with cerebrovascular diseases. The measurement was made by a gamma-ray scintillation camera assisted by a minicomputer. A diffusible indicator of
133
Xe for CBF determination and a nondiffusible indicator of 99m Tc for MIT determination were used.

The relation between rCBF and MTT showed a negative correlation in the nonfocal areas. The rCBF value in patients with normal brain was constant at high and low blood pressures. In patients with cerebral infarction there was a positive correlation between rCBF and mean arterial blood pressure. MTT had a negative correlation with mean arterial blood pressure in both patients with normal brain and those with cerebral infarction. In patients with normal brain a good negative correlation between CVV and CVR was found. In the nonfocal areas of cerebral infarction a high level of CVR was maintained regardless of the level of CVV.
A Comparison of Betahistine Hydrochloride With Placebo for Vertebral-Basilar Insufficiency: A Double-Blind Study
Authors: SPRUILL JAMES H. , TOOLE JAMES F. , KITTO WILLIAM , MILLER HERSEY E.
Published: June 2011

To test the effectiveness of betahistine HCl in reducing the frequency of transient ischemic attacks (TIAs) caused by vertebral-basilar artery insufficiency, we randomly assigned 26 patients with a typical history of the condition to a placebo-drug or a drug-placebo sequence, each sequence lasting two months. During the study, the frequency of TIAs did not differ significantly between the placebo and the drug groups. Subjective responses indicated some value for betahistine as a palliative agent.
Blood Flow Measurements and the "Look Through" Artifact in Focal Cerebral Ischemia
Authors: DONLEY ROBERT F. , SUNDT THORALF M. , ANDERSON ROBERT E. , SHARBROUGH FRANK W.
Published: June 2011

Regional cerebral blood flow (CBF) was measured (intra-arterial injections of
133
Xe) and electroencephalograms (EEG) were recorded periodically before, for two hours during, and for one and one-fourth hours after middle cerebral artery (MCA) occlusion in 20 squirrel monkeys (
Saimiri sciureus
). A CBF-Pa

co
co2

response curve for these animals under barbiturate anesthesia was created from CBF values prior to MCA occlusion and during the time a steady state was being achieved. The animals were subdivided into four groups (five monkeys in each) on the basis of Pa

co
co2

values: 20, 36, 40, and 60 mm Hg. CBF values from this study were compared to previous results obtained with
35
Kr. The phenomenon of "look through" and the importance of recognizing this artifact and its significance in analyzing CBF results in areas of focal ischemia are discussed. The present results were correlated with cerebral ATP and lactate concentrations in ischemic regions determined in previous studies using this preparation at these Pa

co
co2

values and at comparable time intervals before, during, and after MCA occlusion. The EEG appears to reflect the state of ischemic brain accurately. However, CBF measured by the
133
Xe method can be misleading in regard to the true degree of ischemia resulting from occlusion of an intracranial vessel and cannot be relied on to demonstrate accurately "steal" or "reverse steal" due to changes in Pa

co
co2

.
Brain Scanning in Cerebral Vascular Disease: A Reappraisal
Authors: WELCH DENNIS M. , COLEMAN R. EDWARD , HARDIN WILLIAM B. , SIEGEL BARRY A.
Published: June 2011

The frequency of abnormal brain scans in patients with cerebral vascular disease admitted to a stroke intensive care unit has been evaluated in relation to diagnosis, time after onset of symptoms, effect of delayed imaging and the degree of clinical neurological recovery. In patients with completed thromboembolic infarction, 33% had abnormal scans including 39% of those with hemispheric lesions and 14% with posterior fossa lesions. Completed hemorrhagic infarction occurred in seven patients, and three (43%) had abnormal brain scans. Of 14 patients with either transient ischemic attacks or reversible ischemic neurological deficit, two (14%) had abnormal scans. Twenty-seven percent of brain scans in patients with completed thromboembolic infarction were abnormal in the first two days after infarction, a higher frequency than previously reported. Delayed images confirmed the initial interpretation that the scan was either normal or abnormal in 71% of the cases while in 10% of the cases only the delayed views were abnormal. The frequency of abnormal scans was significantly greater in patients who died or had a large neurological deficit at discharge than in patients with lesser residual deficit.
Estimating Total Cerebral Blood Flow From the Initial Slope of Hydrogen Washout Curves
Authors: DOYLE T. F. , MARTINS A. N. , KOBRINE A. I.
Published: June 2011

An initial slope index of total cerebral blood flow, measured by the hydrogen clearance technique, shows a high correlation with flows calculated by bicompartmental analysis. In 247 flow measurements done on 41 rhesus monkeys, a linear regression analysis between these two methods of calculating flow shows a correlation coefficient of 0.928 with a standard error about
y
values of ± 7.63. The initial slope index is not only faster but does not require that a steady state be maintained for ten minutes.
The Effect of Cerebral Infarction on the Regional Cerebral Blood Flow of the Contralateral Hemisphere
Authors: LAVY SYLVAN , MELAMED ELDAD , PORTNOY ZIPPORA
Published: June 2011

Regional cerebral blood flow (rCBF) measurements were performed over the contralateral hemisphere by the
133
Xe intracarotid injection method in 20 patients with acute cerebral infarction in the territory of the internal carotid artery. The rCBF was found to be reduced, sometimes remarkably, in all of the patients. The mean reduction was 30% to 36% from the lowest normal value for the mean age of these patients. In the younger age group (40 to 59) the reduction was greater, 40% to 47% from the lowest normal value for this age.

The rCBF depression was not related to cerebral dominance, previous hypertension or arterial Pco
2
levels. It occurred in both patients who were fully alert and those with disturbances of consciousness, although it tended to be more diminished in the latter.

It can be assumed that the flow reduction in the nonaffected hemisphere is part of a general phenomenon affecting the entire brain and caused by globally reduced cerebral metabolism.
Spontaneous Thrombosis of Deep Cerebral Veins: A Complication of Arteriovenous Malformation
Authors: GARCIA JULIO H. , WILLIAMS J. POWELL , TANAKA JUNICHI
Published: June 2011

An uncommon type of stroke in children is presented. An intracranial arteriovenous malformation in a 13-year-old boy spontaneously occluded about 22 months after surgical intervention. Precipitating factors, such as bacterial infections, could not be demonstrated in this patient, who had been attending school since the time of the craniotomy. The histological features of venous encephalomalacia in the galenic territory are contrasted with hemorrhagic encephalomalacia as seen after arterial occlusions: in the former, hemorrhages are more widespread and edema is more pronounced.
Regional Cerebral Blood Flow Estimated by
133
Xenon Inhalation
Authors: OBRIST WALTER D. , THOMPSON HOWARD K. , WANG HSIOH SHAN , WILKINSON WILLIAM E.
Published: June 2011

A method is described for estimating the clearance rate and fractional blood flow of the fast (gray matter) compartment of the brain from the first ten minutes of
133
Xe clearance curves, following a one-minute inhalation. Computer-simulated data were used to test the adequacy of the two-compartmental model employed, and to evaluate the stability of the parameters in the presence of random noise. A comparison was made between this approach and the previously reported three-compartmental analysis. Regional cerebral blood flow data were obtained on 48 young control subjects and 20 elderly demented patients. Hemispheral regional, and test-retest variations were determined, as well as differences between the groups.
Detailed Description of a Cranial Window Technique for Acute and Chronic Experiments
Authors: LEVASSEUR JOSEPH E. , WEI ENOCH P. , RAPER A. JARRELL , KONTOS HERMES A. , PATTERSON JOHN L.
Published: June 2011

Methods for implantation of cranial windows for the direct observation of the pial microcirculation in experimental animals are described in detail. These techniques are suitable for both acute experiments in anesthetized animals and chronic implantation permitting several months of observation in awake animals. Experience over several years shows that these techniques have an acceptably low rate of failure, are low in cost and can easily be mastered in most laboratories. They make possible observation of the microcirculation and accurate measurement of the diameter of pial vessels, and permit study of the effects on the microcirculation of a variety of maneuvers and vasoactive agents which can be studied by direct application as well as by intravascular administration. Because they preserve the integrity of the skull, the techniques permit study of the cerebral microcirculation under conditions closely approximating the normal environment of these vessels.
Therapy Against Brain Swelling in Stroke Patients
Authors: CANDELISE LIVIA , COLOMBO ALVARO , SPINNLER HANS
Published: June 2011

The effectiveness of cerebral antiedema agents in stroke has been questioned. Animal and clinical work is inconclusive about steroids and osmotic drugs. A retrospective study of a continuous series of 227 stroke patients treated in the acute stage (some with dexamethasone alone, some with dexamethasone plus hyperosmotic mannitol infusions, and some without antiedema therapy) showed no significant difference in the ten-day survival rate. On this criterion, there is no ground for the systematic use of such agents against this type of brain swelling.
Regional Cerebral Blood Flow Measured by the Gamma Camera After Direct Injection of
133
Xe into the Distal Stump of the Occluded Middle Cerebral Artery
Authors: OTT ERWIN O. , ABRAHAM JACOB , MEYER JOHN STIRLING , TULLEKEN CORNELIUS A. F. , MATHEW NINAN T. , ACHARI AMRIT N. , AOYAGI MINORU , DODSON RONALD F.
Published: June 2011

Regional cerebral blood flow (rCBF) was measured after intracarotid injection of
133
Xe concurrently with measurements of local cerebral blood flow (LCBF) after injection of
133
Xe directly into the distal stump of the occluded middle cerebral artery (MCA) by the use of the gamma camera after producing experimental ischemia in baboons by occluding the MCA. Regional MCA stump pressure (rMCAP) was also measured. Regions of ischemia assessed by intracarotid injection of
133
Xe correlated well with the territory of infarct defined by injection of
133
Xe into the distal MCA stump. Flow values in ischemic regions obtained by direct injection of
133
Xe into the MCA were 15% to 20% lower than those obtained by intracarotid injection of
133
Xe. Possible explanations for these differences are discussed. During induced hypertension autoregulation in ischemic areas was abolished and paradoxical responses of LCBF and rMCAP to changes in arterial carbon dioxide tension (Pa

co
co2

) were confirmed.
Carotid Arterial Elastic Hyperplasia in a Newborn
Authors: THOMPSON JOEL A. , GRUNNET MARGARET L. , ANDERSON ROBERT E.
Published: June 2011

Cerebrovascular insufficiency in infancy and childhood is well documented and has a diverse and often unknown etiology. Reported here is a polycythemic, microcephalic infant girl of 43 weeks' gestation with bilateral cerebral infarction occurring in the perinatal period. Infarction was the result of bilateral carotid artery stenosis produced by massive reduplication of the internal elastic lamina. Review of the literature failed to reveal any reports of similar arterial lesions. The angiographical picture was also unique.

The etiology of this unusual defect is not known, but we believe the problem was congenital perhaps due to an intrauterine infectious process.
The Production and Clinical Features of a Chronic Stroke Model in Experimental Primates
Authors: SYMON LINDSAY , C.DORSCH N. W. , CROCKARD H. A.
Published: June 2011

The characteristics of stroke in baboons produced by transcranial occlusion of the middle cerebral artery were studied by clinical examination and serial cinematographic studies, the animals being maintained for three years following the stroke. The characteristic deficit in all animals was an initial, fairly dense faciobrachial weakness with, in a few instances, some accompanying leg weakness for a few days, rapidly improving over the first few months. Some animals retained very evident arm weakness; most animals retained weakness of the face; the majority showed recovery of reaching and placing reactions and some movement in all joints ofthe upper limb, although fine movements of the fingers remained invariably impaired. Homonymous hemianopia, at least to attention, also appeared to be characteristic, but all of the animals recovered a normal gait and leaping was regained. The close correlation between this and human stroke appears to confirm that middle cerebral artery occlusion in the baboon is a reliable, repeatable and acceptable stroke model.
Local Cerebral Blood Flow and Vascular Reactivity in a Chronic Stable Stroke in Baboons
Authors: SYMON LINDSAY , CROCKARD H. A. , C.DORSCH N. W. , BRANSTON N. M. , JUHASZ J.
Published: June 2011

Blood flow in the hemispheres of baboons three years after middle cerebral artery occlusion has been assessed by the hydrogen clearance technique. Blood flow in the infarct itself varied from very low (8 ml/100 gm per minute) to very high (89 ml/100 gm per minute) values and, averaging the values for the infarct as a whole, it was impossible to distinguish average flows in the infarct from those of the normal hemisphere. Flow values in surrounding zones of the infarct remained significantly lower than those of comparable normal hemispheres, and, excluding the infarct, the mean average hemispheral blood flow was 35.2 ml/100 gm per minute. This indicates a significant reduction in flow in the cortex, subsequently shown histologically to be normal, compared with normal blood flow values for the baboon hemisphere. Autoregulation was lost in the infarct and impaired in surrounding tissue. CO
2
reactivity was grossly reduced in the hemisphere as a whole but was present in all areas, even occasionally in electrode placements within the infarct itself. After perfusion fixation of the head, pathological study of the area of infarction showed a fairly consistent distribution, the infarct itself consisting of many dilated blood vessels of non-capillary nature scattered among fibrous tissue in what was virtually a glial scar.
Patterns of Cerebrovascular Disease in Japanese and Other Population Groups in Hawaii: An Angiographical Study
Authors: BRUST RAYMOND W.
Published: June 2011

Angiograms of the carotid system were analyzed for incidence and type of intracranial and extracranial lesions in 296 patients with a final diagnosis of non-hemorrhagic stroke. These patients represent all the major ethnic groups in Hawaii. A significant difference was found between the ratio of frequency of involvement of the extracranial and intracranial vessels in Caucasian and that in the Hawaiian-born Japanese populations, similar to that reported by others in native Japanese. The Filipino, Chinese, Hawaiian and part-Hawaiian populations showed no such significant difference.
Intracranial Aneurysms and Subarachnoid Hemorrhage. A Cooperative Study. Antifibrinolytic Therapy in Recent Onset Subarachnoid Hemorrhage
Authors: NIBBELINK DONALD W. , TORNER JAMES C. , HENDERSON WILLIAM G.
Published: June 2011

In this cooperative study among 13 institutions, 502 patients were treated with antifibrinolytic medication (epsilon-aminocaproic acid or tranexamic acid) within a 14-day period following rupture of an intracranial aneurysm. Mortality at the end of 14 days was 11.6%; proved rebleed rate was 12.7%. Patients with an internal carotid or anterior cerebral aneurysm had the highest mortality and rebleed rate. Most rebleeds occurred between the sixth and eleventh days following the initial bleed. Significantly higher mortality was reported among patients with cerebral vasospasm, yet rebleed rate was no different among those patients with or without vasospasm. The same pattern was observed among patients with a mean blood pressure value above and below 110 mm Hg. We conclude that antifibrinolytic therapy provides beneficial treatment to patients with recent onset Subarachnoid hemorrhage (SAH) following rupture of an intracranial aneurysm.
Brain Scan in Cerebral Ischemia
Authors: TURNER J. HARVEY
Published: June 2011

A rapid embolic method for consistent induction of stroke in the rat is described. Brain scans were performed using a micro-pinhole collimator system, and the value of the model for studies in localization of radiopharmaceuticals in cerebral ischemia is demonstrated.
Pathogenetic similarity of strokes in stroke-prone spontaneously hypertensive rats and humans.
Authors: Yamori Y , Horie R , Handa H , Sato M , Fukase M
Published: June 2011

The predilection sites of cerebrovascular lesions (cerebral hemorrhage and/or softening) were studied in 1,278 stroke-prone spontaneously hypertensive rats (SHRSP). The precise supply to the main cerebral arteries was determined by trypan blue injections and microangiography. The three major territories were the anteromedial cortex, the occipital cortex, and the basal ganglia. A common angioarchitectural characteristic of these three areas was the blood supply through "recurrent branching" from the main stream. In the basal ganglia, where there is a preponderance of lesions, the arteries responsible for these lesions belonged to the lateral group of lenticulostriate arteries. The primary pre-stroke arterial lesions were further studied microangiographically in SHRSP killed at the time the initial symptoms of stroke were detected. These points were located at the "boundary zone" of the main cerebral arteries. Our findings indicated the importance of these two angioarchitectural minor loci as the basis for functional or organic circulatory disturbances that may cause stroke. Since these local factors of stroke are common in the cortex and basal ganglia of rats and basal ganglia of humans, these SHRSP are regarded as good pathogenetic models for studies on stroke in humans.
Fate of stroke patients transferred to a long-term rehabilitation hospital.
Authors: Miglietta O , Chung T S , Rajeswaramma V
Published: June 2011

The rehabilitation outcome of 25 elderly hemiplegic patients discharged from the rehabilitation facilities of an acute general hospital and admitted to a long-term facility hospital was evaluated. Only those patients who had been on a rehabilitation program and were discharged after an average of 11 weeks because of lack of progress or severity of their functional and/or neurological disability were considered for this study. Twenty-two patients were wheelchair bound on admission and severely dependent in most self-care activities. Improvement in function and performance occurred in ten patients, while 13 patients remained unchanged. Among the improved patients, eight became ambulatory and independent in activities of daily living (ADL), eight became independent from a wheel-chair level, and eight returned home or to the community. The average stay of the patients in the chronic rehabilitation care facility was seven months, although all the patients reached their maximum level of performance within six months. It appears from this study that some hemiplegic patients require a long and intensive rehabilitation program.
XIII. Cerebral circulation and metabolism in stroke. Cerebral circulation and metabolism in stroke study group.
Authors: Scheinberg P , Meyer J S , Reivich M , Sundt T M , Waltz A G
Published: June 2011

An understanding of the cerebral circulation is so fundamental to comprehension of the pathogenesis of stroke that cerebral blood flow and metabolism merit review in this series of reports. The authors recognize that the research described here is very technical in nature and may appear to have little practical application to clinical medicine. Nevertheless, these matters are basic to the development of precise methods for the measurement of regional cerebral blood flow in man which could be used to monitor the therapy of stroke with greater success than is possible at present.
Distribution of cardiac output in dogs during intravenous infusion of betahistine.
Authors: Smith K A , Meyer M W
Published: June 2011

Cardiac output (CO), arterial blood pressure (ABP), heart rate (HR), blood gases and blood flow (BF) to the brain, heart, kidney and skeletal muscles and other cephalic tissues in five dogs were studied before and at 30 minutes of betahistine infusion (0.12 to 0.2 mg per minute per kilogram). The particle distribution method using radioactive labeled 141Ce (15 mu) and 85Sr (15 mu) microspheres was utilized to quantitate and assess BF and CO. In the five dogs, the increase in CO averaged 20.8%, ABP remained constant, and HR increased in all but one exception where it decreased slightly concomitant with a decrease in Paco2. Brain BF increased (+ 29.6%) in the dogs whose Paco2 reamined constant. The BF increased to the heart (25.4%) and skeletal muslce (80%), while BF to the kidney and other tissues did not change. The change in HR appears to account for the change in CO. The dilating effect of betahistine on blood vessels, in the skeletal muscle, brain and heart could reduce peripheral resistance and decreace ABP. Thus, the increase in HR may be mediated through baroreceptor mechanisms rather than by a direct effect of betahistine. In addition, a decrease in Paco2, is more effective for decreasing cerebral BF than betahistine is for increasing blood flow.
The "richness" of sympathetic innervation. A comparison of cerebral and extracerebral blood vessels.
Authors: Rosenblum W I
Published: June 2011

The number of adrengeric nerves was quantified, on both cerebral and femoral blood vessels. No difference was found between the two vascular beds. The data failed to establish a "richer" innervation of cerebral vessels. This is in agreement with my previous, extensive, subjective, and unpublished impression. Consequently, the suggestion of others, which ascribes certain features of cerebrovascular behavior to an unusually rich vascular innervation, remained unproved.
Effect of beta-adrenergic blockade with propranolol on cerebral blood flow, autoregulation and CO2 responsiveness.
Authors: Aqyagi M , Deshmukh V D , Meyer J S , Kawamura Y , Tagashira Y
Published: June 2011

Cerebral autoregulation and vasomotor responsiveness to carbon dioxide were measured quantitatively in normal baboons and after intravertebral or intravenous of the beta-adrenergic blocking agent, propranolol hydrochloride (Inderal). Continuous measurements were made of cerebral blood flow (CBF: measured as bilateral internal jugular venous outflow using an electromagnetic flowmeter), cerebral perfusion pressure (CPP), arterial Po2 and Pco2 and venous Po2, cerebral arteriovenous oxygen difference and endotracheal Pco2. The autoregulation index (A.I. = deltaCBF/deltaCPP) and the chemical index (C.I.= deltaCBF/deltaPaco2), were used as quantitative measures.