bluuebunny/crossref_metadata_2025 huggingface dataset:
Transcranial Doppler ultrasonography during cardiopulmonary bypass in patients with severe carotid stenosis or occlusion.
Authors: von Reutern G M , Hetzel A , Birnbaum D , Schlosser V
Published: June 2011

Blood flow velocity of the middle cerebral artery was monitored during cardiopulmonary bypass procedures by means of transcranial Doppler ultrasonography. Our investigation was carried out in a group of 16 patients with severe carotid stenosis or occlusion and in a control group of 42 patients with no or stenosis of less than 50% local diameter reduction. After onset of cardiopulmonary bypass, both groups showed a short unstable phase followed by increased blood flow velocity (10% increase ipsilateral to the obstruction, 27% increase in the control group). Just before rewarming, blood flow velocity was still comparable to (control group -3%) or higher than (ipsilateral to obstructions +14%) prebypass values. Analysis of three patients with postoperative diffuse encephalopathy did not reveal reduced blood flow during cardiopulmonary bypass as a relevant factor. Two of the three showed luxury perfusion. Reduced perfusion due to carotid obstruction was not observed during cardiopulmonary bypass and therefore cannot be considered a significant risk factor for the development of intraoperative stroke.
Effects of prostacyclin, indomethacin, and heparin on cerebral blood flow and platelet adhesion after multifocal ischemia of canine brain.
Authors: Kochanek P M , Dutka A J , Kumaroo K K , Hallenbeck J M
Published: June 2011

Seven anesthetized dogs treated with prostaglandin I2, indomethacin, and heparin were compared with 12 controls to test the hypothesis that the salutary effect of treatment on recovery of neuronal function and cerebral blood flow (CBF) after ischemia is coupled to the inhibition of platelet accumulation. In this model of right hemisphere multifocal ischemia, cortical somatosensory evoked response (CSER) amplitude, 14C autoradiographic blood flow, and 111In-labeled platelet accumulation were measured. The ratio of injured to noninjured hemispheric 111In activity (cpm/g) provided an index of platelet accumulation. Treatment improved CBF of the injured hemisphere compared with control after 4 hours of reperfusion (74 +/- 17 versus 53 +/- 13 ml/100 g/min, p less than 0.05), and it enhanced recovery of CSER amplitude (percent of baseline) after 1 hour of reperfusion compared with control (27.1 +/- 4.7% [treatment] versus 15.5 +/- 2.8% [control], p less than 0.05). However, the effect on CSER was not sustained after 4 hours of recovery. Despite these effects on CSER and CBF, treatment failed to inhibit 111In-labeled platelet accumulation in the injured hemisphere (1.7 +/- 0.3% [treatment] versus 1.5 +/- 0.1% [control], p greater than 0.05). Platelets may adhere to damaged endothelium despite aggressive platelet antiaggregant therapy.
Platelet activity and selective beta-blockade in migraine prophylaxis.
Authors: Joseph R , Steiner T J , Schultz L U , Clifford Rose F
Published: June 2011

Migraine is associated with increased platelet activity and an incidence of cerebrovascular ischemic events. Because cerebrovascular events might result from platelet aggregation, enhancing platelet activity further in the treatment of migraine is not desirable. beta-Adrenoceptor blockers effective in migraine prophylaxis include propranolol (nonselective) and metoprolol (beta 1-selective), but it is uncertain how beta-receptor subtype selectivity might influence platelet behavior in migraine. In 29 patients, comparable clinical responses were obtained with therapeutic doses during 1 month of treatment with propranolol, metoprolol, and the beta 2-selective Li 32-468. Propranolol increased and metoprolol decreased platelet aggregation and ATP release, and the effect of Li 32-468 could be related to that of propranolol. These actions can be largely explained in terms of what is known of platelet beta-receptors and therefore can be generalized to other effective beta-blockers. Since altered platelet activity does not account for the efficacy of these agents in migraine, the actions of beta-blockers on platelets should be considered as side effects. Those beta-blockers inhibiting platelet activity should be preferred in migraine treatment, assuming equal efficacy, which implies the use of beta 1-selective blockers.
Assessment of interobserver variability in a Dutch multicenter study on acute ischemic stroke.
Authors: Gelmers H J , Gorter K , de Weerdt C J , Wiezer H J
Published: June 2011

Quantitative assessment of patient data is a pertinent part of controlled clinical studies. When several centers are involved, the degree of agreement between different observers becomes important. Therefore, in addition to developing a multicenter study on acute ischemic stroke, we have estimated the interobserver agreement expressed in terms of kappa statistics. Twelve patients suffering from neurologic deficits due to acute ischemic stroke were examined by four investigators, and the results were assessed using the Mathew scale. Considerable interobserver variability was found. Agreement on items based on subjective information from the patient was low, and it is also possible that this information changes with time. It is advised that in the development of assessment scales, items with low interobserver agreement should be avoided.
Effect of profound hypermagnesemia on spinal cord glucose utilization in rats.
Authors: Szabo M D , Crosby G
Published: June 2011

The purpose of our study was to investigate the effect of hypermagnesemia on spinal metabolic rate. The 2-[14C]deoxyglucose technique was used to measure regional glucose utilization in the lumbar spinal cord of paralyzed, mechanically ventilated rats receiving 70% nitrous oxide and an intravenous infusion of either saline (n = 5) or magnesium sulfate (n = 5). Plasma magnesium concentrations were 6.75 +/- 0.5 and 0.9 +/- 0.5 mM (p less than 0.01) in hypermagnesemic and control rats, respectively. Hypermagnesemic rats were hypotensive (88 +/- 1 vs. 130 +/- 4 mm Hg, p less than 0.01) but blood pressure remained within the autoregulatory range. Glucose utilization was reduced 26-45% in spinal gray matter and 53-63% in spinal white matter during hypermagnesemia. We conclude that magnesium is a potent spinal metabolic depressant and that this action, which is unusually prominent in spinal white matter, is a plausible explanation for the recently reported beneficial effect of magnesium therapy during spinal cord ischemia.
Vascular response to carbon dioxide in areas with and without diaschisis in patients with small, deep hemispheric infarction.
Authors: Takano T , Nagatsuka K , Ohnishi Y , Takamitsu Y , Matsuo H , Matsumoto M , Kimura K , Kamada T
Published: June 2011

The reactivity of cerebral blood vessels to changes in PaCO2 in areas of the cerebral cortex with or without diaschisis was investigated in 13 patients in a subacute or chronic stage after a small capsular infarct. A focal area of hypoperfusion (area of diaschisis) was detected in the ipsilateral sensorimotor cortex in each patient. Hyperventilation caused a significant reduction of regional cerebral blood flow in the area without diaschisis and only a tendency for regional cerebral blood flow to decrease in the area with diaschisis; CO2 inhalation induced a slight increase in regional cerebral blood flow in the area without diaschisis and a significant increase in regional cerebral blood flow in the area with diaschisis. Regional cerebral blood flow reactivity to hypocapnia was significantly less in the area with diaschisis than in the area without, whereas the hypercapnic response was more marked in the area with diaschisis than in the area without. Our results suggest that in the area with diaschisis, the arterioles may be abnormally vasoconstricted at rest such that they cannot constrict further in response to hypocapnia but can dilate more during hypercapnia than in the area without diaschisis. This excessive resting vasoconstriction may result from decreased tissue elaboration of CO2 due to local decrease of metabolic function.
Use of diastolic velocity ratios to predict significant carotid artery stenosis.
Authors: Friedman S G , Hainline B , Feinberg A W , Lesser M L , Napolitano B A
Published: June 2011

Duplex scanning of the carotid bifurcation has emerged as an accurate noninvasive means of predicting and quantifying carotid arterial stenoses. Compared with the more widely reported measurements of spectral broadening and peak frequency ratios, measurements of diastolic velocity ratios have theoretical advantages in predicting carotid artery stenosis. The use of diastolic velocity ratios between the internal and common carotid arteries was prospectively studied in 30 consecutive patients to determine its accuracy in predicting significant stenosis of the internal carotid artery when compared with angiography. A total of 55 carotid bifurcations were studied, and the use of diastolic velocity ratios correctly predicted high-grade stenosis (greater than or equal to 75% diameter reduction) in 52 cases (95%). We conclude that diastolic velocity ratios may be used to accurately detect significant internal carotid artery stenosis.
Transcranial Doppler.
Authors: DeWitt L D , Wechsler L R
Published: June 2011

TCD recording of flow velocities in intracranial vessels was first described by Aaslid in 1982. The utility of this instrument becomes more apparent as it is used in different clinical settings and compared with angiographic findings (Figures 1 and 2). Its importance in early detection of vasospasm in subarachnoid hemorrhage is now clearly known; increased flow velocity can be documented prior to neurologic deterioration and thus allow early institution of therapy. In patients with stroke or transient ischemic attack of unclear etiology, especially in blacks, Orientals, or females, who have a higher incidence of intracranial arterial disease, TCD can be a very important noninvasive means for detecting stenosis of intracranial vessels. Its value for assessing collateral circulation, intraoperative monitoring, and measuring CBF is quite promising. Hopefully, through further work with TCD, we will be able to clarify the spectrum of its usages as well as its limitations, though the preliminary data indicate that it should be an important addition to present noninvasive evaluations.
Young adult stroke: neuropsychological dysfunction and recovery.
Authors: Ferro J M , Crespo M
Published: June 2011

Etiology, neuropsychological deficits, aphasia type, and recovery were retrospectively studied in 254 young adults with stroke. Cardiac embolism was the most common cause of stroke in patients younger than 40, while atherosclerosis was the most frequent etiology among those aged 41-50 years. In 166 aphasic patients, Broca's aphasia was the most common while Wernicke's and transcortical aphasias were rare. Compared with an older aphasic population, young patients had significantly more nonfluent aphasias and fewer comprehension deficits. These differences were related to stroke localization: the majority of infarcts localized by computed tomography in 37 patients involved either the entire middle cerebral artery territory or its superior or deep branches, explaining the preponderance of nonfluent aphasia. Prognosis of aphasia in our patients was better than has been reported for non-age-selected aphasia populations. Roughly one third of our patients recovered completely, one third improved, and one third had an unresolved language deficit. Complete recovery and significant improvement were observed even greater than 6 months after stroke. In some patients, recovery was much better than might have been predicted from lesion site and size depicted on computed tomograms.
Dextromethorphan protects against cerebral injury following transient focal ischemia in rabbits.
Authors: Steinberg G K , George C P , DeLaPaz R , Shibata D K , Gross T
Published: June 2011

We investigated dextromethorphan, both a dextrorotatory opioid derivative and a clinically tested N-methyl-D-aspartate (NMDA) receptor antagonist, in a rabbit model of transient focal cerebral ischemia. Fourteen rabbits were randomly assigned to treatment with a 20 mg/kg i.v. loading dose followed by a 10 mg/kg/hr infusion of 0.4% dextromethorphan in normal saline or with an equivalent volume of normal saline alone. One hour after treatment, the rabbits underwent a 1-hour occlusion of the left internal carotid and anterior cerebral arteries followed by 4 hours of reperfusion. The seven dextromethorphan-treated rabbits showed a significant decrease in the area of neocortical severe ischemic neuronal damage (10.5%) compared with the seven normal saline-treated controls (49.6%, p less than 0.001). The dextromethorphan-treated rabbits also demonstrated significantly smaller areas of cortical edema (10.2%) on magnetic resonance imaging than the controls (38.6%, p less than 0.01). Analysis of somatosensory evoked potentials revealed recovery of the ipsilateral amplitude to contralateral values within 5 minutes of reperfusion in the dextromethorphan-treated rabbits but not in the controls (p less than 0.01). In our rabbit model of transient focal cerebral ischemia, dextromethorphan appears to protect the brain against ischemic neuronal damage and edema, as well as to promote neurophysiologic recovery. This clinically available drug should be further investigated as having potential therapeutic value in the treatment of stroke.
Natural History of Stroke in Rochester, Minnesota, 1945 Through 1954
Authors: WHISNANT JACK P. , FITZGIBBONS JOHN P. , KURLAND LEONARD T. , SAYRE GEORGE P.
Published: June 2011

The records of the Mayo Clinic have been used as the primary basis for the study of stroke in the population of Rochester, Minnesota, from 1945 through 1954. The incidence rate for first stroke of all types was 1947/100,000/year. The rates increased with age, and at age 65 to 74 years, about 1% of the population was affected annually. No significant differences were noted between men and women. The rate for cerebral thrombosis was 146/l00,000/year for all ages. Cerebral hemorrhage represented less than 10% of all strokes and occurred in less than 15% of those who died; this is contrary to what is published in the
U.S. Mortality Statistics
. The prevalence rate was 547/100,000 on January 1, 1955. Twenty-one percent of these persons who had previously had a stroke were functioning with no incapacity on the date of prevalence determination and only 3% were bedridden. Death certificates were reviewed for all those who died after a stroke. Among those who died within a month after a stroke, some type of stroke was noted as the underlying or an associated cause of death in 91%. However, among those who died more than a month after a stroke, only 54% had such a diagnosis recorded. Probability of surviving after each type of stroke was determined and compared with survival in a normal population. The curve showing probability of surviving from cerebral thrombosis diverges throughout its course from that of the expected survival but diverges more sharply in the first several months. Among those patients with stroke who died, 41% died of causes related to the acute stroke and 10% died of a subsequent stroke. Heart disease was the cause of nearly twice as many deaths as was a subsequent stroke among those who survived the initial stroke. Autopsies were performed on approximately 50% of those persons who died following a stroke, and information from these studies confirmed the high degree of accuracy of the clinical appraisals.
The Role of the Sympathetic Nervous System in Lipid Deposition. I. Increased Lipid Deposits in the Iris of the Sympathectomized Eye in Rabbits Fed an Atherogenic Diet
Authors: AUSTIN JAMES , ROBERTS WILLIAM , NEVILLE HANS , ARMSTRONG DONALD
Published: June 2011

Rabbits on a high-cholesterol diet deposit more lipid in the iris of the sympathectomized eye.

Histologically, the lipid deposits are composed of sudanophilic staining droplets localized both in smooth muscle cell cytoplasm of the iris dilator muscle and in larger oval cells. Possible metabolic and vascular mechanisms are noted which may underlie these findings. Potential clinical implications of these findings are cited.
The Electrical Activity of the Heart and Brain Under Acute Experimental Anoxia: The Protective Effect of Polarizing Solutions
Authors: ARIZA-HERRERA DANIEL , SODI-PALLARES DEMETRIO , SAENZ-ARROYO LUIS , CISNEROS FERNANDO , BISTENI ABDO , DEL MERCADO JOSE VAZQUEZ
Published: June 2011

Acute anoxia was produced in 80 dogs under anesthesia with sodium pentobarbital. Respiration was maintained with a Palmer's pump through an endotracheal tube. The anoxia was produced by stopping the pump and occluding the endotracheal tube. Polarizing solution (glucose-potassium-insulin) was perfused in 40 of the animals, starting three hours prior to the anoxia. The remaining 40 dogs comprised the control group. Peripheral electrocardiograms, as well as electroencephalograms, were simultaneously recorded before and during the period of anoxia. Recordings were continuously obtained until no more than one ventricular complex in a ten-second period was observed, even though the electrical brain activity had disappeared by this time.

Our present experimental work suggests the beneficial effect of polarizing solutions by delaying the anoxic degradation of the electrical phenomenon of the heart and the brain.
Factors Influencing Stroke Rehabilitation
Authors: STERN PETER HANS , MCDOWELL FLETCHER , MILLER JAMES M. , ROBINSON MARILYN
Published: June 2011

Quantitative and semiquantitative methods have been used to evaluate the clinical improvement of 62 patients with completed stroke who were admitted to a rehabilitation hospital.

Improvement in motility and leg strength on the paretic side was minimal and was not influenced by facilitation exercise techniques. Observed changes in strength and motility occurred to about the same degree on both the nonparetic and paretic sides. Patients who had a short interval between onset of stroke and admission to the rehabilitation program improved significantly more on the paretic side than those with a longer interval. Practically no improvement in motility and leg strength was found two months following a stroke.

Hemiplegia and hemiparesis were defined quantitatively on the basis of motility test scores. Patients with hemiparesis showed greater improvement in motility and self-care status in about half the time of hospital stay when compared with patients with hemiplegia. In spite of relatively static neurological deficits, all patients showed evidence of functional improvement as assessed by a self-care rating scale. The poorest functional outcome was seen in patients who had hemisensory losses in addition to hemiplegia. The observations indicate that early, functionally oriented stroke rehabilitation programs offer the best chance of aiding patients. Behavioral and sociological influences on final outcome are important and must be carefully evaluated to insure maximum chances of successes in rehabilitation.
Strokes in the Young
Authors: ABRAHAM JACOB , SHETTY G. , JOSE C. J.
Published: June 2011

Of 407 consecutive patients with cerebrovascular disease seen from July 1967 to June 1969 in a prospective study of stroke being conducted by the Department of Neurological Sciences at Christian Medical College Hospital, Vellore, South India, 127 (32%) patients were between the ages of 11 and 40. Using the standard criteria for diagnosis, 50% of the patients had cerebral thrombosis, 13% had cerebral embolism, 13% had internal carotid artery thrombosis (a subcategory of cerebral infarction), and the remainder were distributed through the other categories of cerebrovascular disease. Hypertension appeared to be a factor in about 19% of the patients (angiography revealed that the small intracranial vessels were more commonly abnormal than the larger extracranial arteries). Less than 10% of the patients had intracerebral hemorrhage or subarachnoid hemorrhage. The question was raised as to the possible role of arteritis secondary to common tropical diseases in the pathogenesis of these "strokes in the young."
Reactivity of Cerebral Blood Flow to CO
2
in Patients With Transient Cerebral Ischemic Attacks
Authors: THOMPSON STEPHEN W.
Published: June 2011

Cerebral blood flow and its ability to increase in response to inhalation of 6% CO
2
was measured in six patients with a history of transient ischemic attacks in the internal carotid distribution and in ten normal control subjects. Flow was measured with a method which uses time concentration curves made with intravenously injected radioactive indicator and externally placed radiation detectors. It permits measurement of flow, expressed in arbitrary units as a flow index, within the range of a detector placed against the side of the head.

Resting flow indices and the increases in flow indices in response to CO
2
inhalation did not differ significantly between the TIA patients and the normal control subjects. These results are discussed in terms of possible mechanisms of TIA, and it is concluded that the preserved CO
2
responsiveness of the flow indices in these six patients is in support of the theory that intermittent platelet microembolization is an important cause of TIA.
Cerebral ATP and Lactate Levels in the Squirrel Monkey Following Occlusion of the Middle Cerebral Artery
Authors: MICHENFELDER JOHN D. , SUNDT THORALF M.
Published: June 2011

Previous studies have shown that occlusion of the middle cerebral artery (MCA) of the squirrel monkey results in a consistent large infarct; that in the initial two hours after occlusion of the MCA, blood flow in the central area of ischemia continues at a reduced rate (20% to 50% of normal); and that restoration of normal flow within three hours results in a survival rate of 65% without infarction. In this study, cerebral adenosine triphosphate (ATP), lactate, and pyruvate concentrations were measured at various time intervals after occlusion of the MCA. ATP decreased slowly during a three-hour period to 30% of normal, and lactate, after an initial rapid accumulation, increased slowly to about eight times normal. This compares to the effects of circulatory arrest which, in the dog, results in a reduction of the ATP level to 25% of normal within four minutes and a reciprocal increase in the lactate level. Because the effects of total cerebral anoxia are potentially reversible prior to four minutes, and, therefore, at an ATP concentration above 25% of normal, the slow rate of ATP depletion observed in the ischemic monkey brain supports the view that a significant period exists after occlusion of a major intracranial vessel wherein the ischemic effects are potentially reversible. Using the methods of this study, future investigations should permit a meaningful evaluation of the relative merits of those measures recommended for the treatment of acute cerebral ischemia.
Improvement in Motor Performance in Paretic and Paralyzed Extremities Following Nonembolic Cerebral Infarction
Authors: MCDOWELL FLETCHER , LOUIS SYDNEY
Published: June 2011

The problems involved in measuring improvement as well as the conceptual difficulties in considering this phenomenon were considered in general terms.

Data on 300 patients with nonembolic cerebral infarction followed from five to nine years are presented, indicating that improvement in function of a paralyzed extremity may occur in the early phase after stroke but was extremely unlikely to continue during long-term follow-up from three months to five years. It was concluded that improvement in function might be determined more by retraining of the nonaffected muscles and particularly of the unaffected side rather than by recovery of the area paralyzed.
Effects of Betahistine HCl, Nicotinic Acid, and Histamine on Basilar Blood Flow in Anesthetized Dogs
Authors: ANDERSON WESLEY D. , KUBICEK WILLIAM G.
Published: June 2011

An intermandibular-transclival approach to the posterior cranial fossa has been developed which allows exposure of the basilar artery for attachment of a small electromagnetic blood flow transducer. The results of single intravenous injections of betahistine hydrochloride indicated a mean increase in basilar artery blood flow of 54% and a simultaneous decrease in systemic arterial blood pressure of a duration of action of approximately one minute. Histamine phosphate yielded results similar to betahistine hydrochloride, while nicotinic acid produced only slight increases in blood flow in the basilar artery.
The Moving Embolus Seen During Serial Cerebral Angiography
Authors: LIEBESKIND ARIE , CHINICHIAN ALI , SCHECHTER MANNIE M.
Published: June 2011

Movement of an occlusive process in an angiographical study is diagnostic of embolization.

Two cases are reported in which the demonstration of a moving embolism on serial angiography is shown.
A-Mode Echoencephalography in the Evaluation of Cerebrovascular Disease
Authors: SANDOK BURTON A.
Published: June 2011

The value of A-mode echoencephalography was studied in a series of patients with Cerebrovascular disease of various types. The procedure proved to be restricted value limited to those situations in which (1) a midline shift was obtained, and (2) the midline shift was observed within 36 hours after the onset of symptoms.

Whereas after 36 hours some patients with cerebral infarction showed a midline shift (presumably due to edema), such a shift was not noted in patients with cerebral infarct who were examined within 36 hours after its occurrence. Those patients showing a midline shift before this interval should be suspected of having an intracerebral hemorrhage or other intracranial space-occupying process.
Cerebrovascular Disease in the Bi-Racial Population of Evans County, Georgia
Authors: HEYMAN A. , KARP H. R. , HEYDEN S. , BARTEL A. , CASSEL J. C. , TYROLER H. A. , CORNONI J. , HAMES C. G. , STUART W.
Published: June 2011

An epidemiological study was made of cerebrovascular disease in a bi-racial Southern community. The study population comprised about 3,000 men and women aged 15 to 75 years at the time of entry into the study. During the 87-month period between the initial and second examinations, 94 persons developed their first cerebrovascular event.

The incidence of stroke among white men (4.77/1,000/year) was almost four times that in white women and more than twice that reported for white men in other sections of the country. The incidence rates of stroke in Negro men and women were equal (5.8/1,000/year).

The risk factors predisposing to stroke in white men appeared to be severe hypertension, obesity, high hematocrit levels, and antecedent electrocardiographical abnormalities These factors were not as prominent among the other race-sex groups.

The high incidence of cerebrovascular disease found in this semirural population of Georgia supports previous reports of increased mortality rates for stroke in this section of the country and represents a unique situation, the exact cause for which remains to be determined.
Retinal Arterial Pressure Before and After Surgery for Carotid Artery Stenosis
Authors: KOBAYASHI SHIGEAKI , HOLLENHORST ROBERT W. , SUNDT THORALF M.
Published: June 2011

This is a study of 45 patients who underwent angiography and surgery of one or both carotid arteries (56 surgical procedures). All patients had detailed neuro-ophthalmological evaluations including determination of retinal artery pressure (RAP) and scrutiny for emboli in small vessels. Preoperatively, the absolute RAP value has a high correlation with the degree of stenosis of the ipsilateral carotid artery when that stenosis exceeds 80%. The asymmetry of RAP values is greatest when the stenosis is much more severe in one artery than in the other. Both RAP values may show an absolute decrease when the stenosis is severe bilaterally. In these patients, postoperatively there usually is not only an increase in the RAP on the side operated on but also on the side contralateral to the initial procedure. Almost without exception, RAP should be normal after carotid artery surgery. The finding of a subnormal RAP after operation demands immediate investigation.
Decline in US stroke mortality. Demographic trends and antihypertensive treatment.
Authors: Klag M J , Whelton P K , Seidler A J
Published: June 2011

Stroke mortality has been falling rapidly in this country since 1973. To investigate age-race-sex effects on stroke mortality, we studied US vital statistics during 1950-1972 and 1973-1981 in 55-64-, 65-74-, and 75-84-year-old race-sex groups. The accelerated rate of decline in stroke mortality since 1973 has had a substantial public health impact, with greater than 200,000 fewer stroke deaths than would otherwise have occurred. For all groups, stroke mortality declined at a greater rate (p less than 0.05) in 1973-1981 than during 1950-1972. The rates of decline during 1973-1981 were greater with increasing age (p less than 0.05) and were more substantial for younger blacks. There were no consistent differences in the rate of decline by sex. The greater rate of decline in absolute stroke mortality in the older age groups and blacks was explained by higher baseline mortality in these groups. Overall, stroke mortality decreased by approximately 2%/yr in 1950-1972 and by approximately 7%/yr after 1973. Rank order of average annual percent decline after 1973 by age-race-sex groups did not correspond to rates of change in treatment or control of hypertension obtained from three national surveys. The accelerated rate of decline after 1973 may have resulted from improved antihypertensive therapy, but our findings fail to confirm this hypothesis and suggest that treatment of hypertension may not be the principal reason for the decline in stroke mortality.
Cerebral autoregulation dynamics in humans.
Authors: Aaslid R , Lindegaard K F , Sorteberg W , Nornes H
Published: June 2011

We studied the response of cerebral blood flow to acute step decreases in arterial blood pressure noninvasively and nonpharmacologically in 10 normal volunteers during normocapnia, hypocapnia, and hypercapnia. The step (approximately 20 mm Hg) was induced by rapidly deflating thigh blood pressure cuffs following a 2-minute inflation above systolic blood pressure. Instantaneous arterial blood pressure was measured by a new servo-cuff method, and cerebral blood flow changes were assessed by transcranial Doppler recording of middle cerebral artery blood flow velocity. In hypocapnia, full restoration of blood flow to the pretest level was seen as early as 4.1 seconds after the step decrease in blood pressure, while the response was slower in normocapnia and hypercapnia. The time course of cerebrovascular resistance was calculated from blood pressure and blood flow recordings, and rate of regulation was determined as the normalized change in cerebrovascular resistance per second during 2.5 seconds just after the step decrease in blood pressure. The reference for normalization was the calculated change in cerebrovascular resistance that would have nullified the effects of the step decrease in arterial blood pressure on cerebral blood flow. The rate of regulation was 0.38, 0.20, and 0.11/sec in hypocapnia, normocapnia, and hypercapnia, respectively. There was a highly significant inverse relation between rate of regulation and PaCO2 (p less than 0.001), indicating that the response rate of cerebral autoregulation in awake normal humans is profoundly dependent on vascular tone.
Nilvadipine attenuates ischemic degradation of gerbil brain cytoskeletal proteins.
Authors: Kuwaki T , Satoh H , Ono T , Shibayama F , Yamashita T , Nishimura T
Published: June 2011

We have previously demonstrated that transient cerebral ischemia induces marked decreases in concentrations of cytoskeletal proteins and have suggested putative involvement of calpain in the decrease of microtubule-associated protein 2 (MAP2) content. We examine the effect of nilvadipine, a new calcium channel blocker, on protein degradation in gerbil brains after 5 minutes of bilateral carotid artery occlusion and compare this effect with those of nimodipine and nicardipine. By densitometric quantification of the electrophoretically separated soluble proteins, mean +/- SEM MAP2 content in the hippocampus (14.4 +/- 1.8 micrograms/mg protein) was depleted (5.4 +/- 0.5 micrograms/mg, p less than 0.01) 4 days after ischemia; this depletion was significantly inhibited by 1 or 10 mg nilvadipine/kg/day. MAP2 content was also depleted in vitro when normal nonischemic brain extract was incubated with calcium, but this degradation was not inhibited by the calcium channel blockers. Our results suggest that calcium channel blockers do not act directly on calpain but act at the calcium channels of neurons and may suppress activation of the enzyme and attenuate ischemic degradation of cytoskeletal protein. We found nilvadipine to be the most potent drug among those studied, and we believe it could be useful for the treatment of cerebral ischemia.
Focal ischemia enhances choline output and decreases acetylcholine output from rat cerebral cortex.
Authors: Scremin O U , Jenden D J
Published: June 2011

Choline concentration is rate limiting in the synthesis of acetylcholine. There is a negative arteriovenous difference for choline concentration across the brain, indicating the steady output of choline from this organ. Cerebral ischemia may increase extracellular choline concentration by interfering with its removal by the circulation and by enhancing its net production from phospholipids. We tested this hypothesis in six rats subjected to middle cerebral artery occlusion. We determined choline and acetylcholine output from the ischemic cerebral cortex by analyzing their concentrations in the fluid contained in cortical cups by gas chromatography-mass spectrometry. Mean +/- SEM choline output over 40 minutes before ischemia (baseline value) was 31.1 +/- 1.6 pmol/min/cm2. During ischemia, mean +/- SEM choline output rose to 100.8 +/- 13, 97.3 +/- 12.7, 100 +/- 22.4, and 93.1 +/- 16.9 pmol/min/cm2 in four consecutive 10-minute periods, respectively. Mean +/- SEM acetylcholine output was 15.6 +/- 1.1 before and 5.9 +/- 1.2, 8.3 +/- 2.6, 8.6 +/- 2.1, and 13.7 +/- 4.6 pmol/min/cm2 in the four 10-minute collection periods during ischemia. All four choline values and the first acetylcholine value during ischemia were significantly different from their respective baseline values. We conclude that ischemia induces an increase in extracellular choline concentration with possible implications for acetylcholine metabolism. The attending transient decline in acetylcholine output may be due to impaired release due to local hypoxia or to decreased acetylcholine synthesis.
Tetramethylpyrazine for treatment of experimentally induced stroke in Mongolian gerbils.
Authors: Ho W K , Wen H L , Lee C M
Published: June 2011

Tetramethylpyrazine, a drug originally isolated from the rhizome of Ligusticum walliichi, has been used routinely in China for the treatment of stroke and angina pectoris. We evaluated this drug by testing its effectiveness in increasing the survival rate in a stroke model using Mongolian gerbils. Our results indicate that tetramethylpyrazine can increase survival rate only if it is administered before the induction of cerebral ischemia. Since we administered the drug intraperitoneally, it is possible that pretreatment was necessary to increase its effective concentration in the blood. Receptor binding studies indicated that tetramethylpyrazine was inactive against a variety of pharmacologically active receptors.
Snoring as a risk factor for sleep-related brain infarction.
Authors: Palomäki H , Partinen M , Juvela S , Kaste M
Published: June 2011

We studied 177 consecutive male patients aged 16-60 years with brain infarction verified by neuroradiology and analyzed the time of onset of stroke symptoms related to sleep and the role of possible or known risk factors for brain infarction. Brain infarction occurred relatively more often during the first 30 minutes after awakening than at any other time. In multiple stepwise logistic regression analyses, snoring was the only independent risk factor differentiating stroke occurring during sleep and stroke occurring either during sleep or during the first 30 minutes after awakening from stroke occurring at other times of the day. The risk ratios were 2.65 (95% confidence interval 1.32-5.29, p less than 0.005) and 3.16 (95% confidence interval 1.61-6.22, p less than 0.001), respectively. Other factors tested were age, arterial hypertension, diabetes mellitus, smoking, alcohol consumption, and body mass index. Arterial hypertension seemed to have an additive effect on the independent risk caused by snoring.
Carotid artery blood flow velocity related to transient ischemic attack and stroke in a population study of 69-year-old men.
Authors: Jungquist G , Nilsson B , Ostberg H , Isacsson S O , Janzon L , Steen B , Lindell S E
Published: June 2011

A population-based sample of 478 men aged 69 years living in Malmö, Sweden, underwent Doppler ultrasonic examination of their carotid arteries; cerebrovascular symptoms and signs were recorded independently. Among 471 men with complete examinations, 117 (25%) showed significant abnormalities in carotid blood flow velocity (moderate stenoses [30-60% diameter reduction] in 20%, severe stenosis [greater than or equal to 60% reduction] or occlusion in 5%). The latter seemingly formed a group separate from the main distribution curve. Stroke was reported in 28 men (6%), during the year before examination in nine (2%). Carotid transient ischemic attack (TIA) was clinically confirmed in one man during this year, while unconfirmed symptoms were reported in 63 (13%). There was a relation between ipsilateral hemispheric stroke/TIA and severe carotid disease (p less than 0.001). Four of seven men with total occlusion had a stroke or a clinically confirmed TIA. Nevertheless, the majority of carotid stenoses (including severe stenoses) were asymptomatic. Cerebrovascular symptoms were not significantly more frequent among the men having moderate stenosis than among those having healthy arteries.
Microfibrillar collagen model of canine cerebral infarction.
Authors: Purdy P D , Devous M D , Batjer H H , White C L , Meyer Y , Samson D S
Published: June 2011

A new canine model of focal cerebral ischemia has been developed employing intravascular delivery of microfibrillar collagen via femoral catheterization. In 13 dogs, dose-effect studies showed neurologic deficits (ranging from mild hemiparesis to death) related to the dose of microfibrillar collagen delivered. In another 10 dogs, 0.5 ml of 60 mg/ml microfibrillar collagen was injected into the common carotid artery; neurologic assessment over 48 hours revealed a survivable stroke syndrome in seven dogs, death at 40 hours in one dog and at less than 12 hours in another, and no clinical effect in one dog. The eight surviving dogs were sacrificed at 48 hours; nine of the 10 dogs had middle cerebral artery distribution infarcts (two grossly hemorrhagic and five grossly nonhemorrhagic) on histologic examination. Angiography in three dogs demonstrated no significant major vascular occlusion. All seven dogs with survivable strokes demonstrated a dense hemiparesis at 24 hours that improved to ambulatory status at 48 hours. The use of microfibrillar collagen to produce middle cerebral artery strokes in dogs provides a new opportunity to study cerebral ischemia without surgery involving the cervical or cranial vasculature. Dogs have larger brains than other common animal models and thus are more amenable to study with imaging modalities. A model with a measurable but survivable insult provides an opportunity for short- and long-term clinical follow-up and for the investigation of therapeutic interventions.
Heparin-induced thrombocytopenia.
Authors: Becker P S , Miller V T
Published: June 2011

There are two types of heparin-induced thrombocytopenia. Type I is more common, has an early onset, and is mild, transient, and benign. Type I is due to direct heparin-induced platelet aggregation and is rarely associated with thromboembolic sequela. Type II is infrequent, has a late onset, and is more severe. Type II is due to an immune-mediated platelet aggregation caused by IgG and IgM that becomes bound to platelets. In Type II, the antibody titers decline over several months; however, early reexposure can result in a catastrophic secondary immune response. Frequently, Type II is associated with life- or limb-threatening thromboembolic complications (white clots), including stroke.
Free protein S deficiency: a possible association with cerebrovascular occlusion.
Authors: Sacco R L , Owen J , Mohr J P , Tatemichi T K , Grossman B A
Published: June 2011

A deficiency of free protein S, known to increase the risk of peripheral venous thrombosis, has not been well described in patients with cerebrovascular disease. In a pilot study of 35 patients with symptomatic cerebrovascular disease, using a qualitative crossed immunoelectrophoresis assay we found eight patients with a free protein S deficiency. A Laurell immunoelectrophoresis assay was used to quantify the percentage of free protein S after removal of the inactive protein S C4b-binding protein complex by precipitation with polyethylene glycol 8000. In a quantitative study of 103 patients with cerebrovascular disease, 21 had a free protein S that was less than 20% of the average normal total protein S concentration (normal range 20-40%); 19 had suffered cerebral infarction and the other two had suffered intracranial hemorrhage. The frequency of free protein S deficiency in this group of stroke patients was far higher than the expected prevalence in the general population.
Changes in hyperfrontality of cerebral blood flow and carbon dioxide reactivity with age.
Authors: Tsuda Y , Hartmann A
Published: June 2011

We evaluated the topographic distributions of regional cerebral blood flow in 51 normal subjects (mean age 41 years) by the xenon-133 inhalation technique. Forty-five of these subjects were divided by age into young normals less than 30 years old (mean age 24 years), middle-aged normals 30-50 years old (mean age 40 years), and elderly normals greater than 50 years old (mean age 62 years); there were 15 subjects in each group. The distributions of vascular CO2 reactivity to hypocapnia were also evaluated in 20 of the normal subjects (mean age 34 years), including 11 younger normals less than 30 years old (mean age 24 years) and nine older (middle-aged or elderly) normals greater than or equal to 30 years old (mean age 45 years). The hyperfrontal distribution of regional cerebral blood flow observed in the young and middle-aged normals was not observed in the elderly normals. The hyperfrontal distribution of vascular CO2 reactivity observed in the younger normals was absent in the older normals. In addition, the correlation between regional cerebral blood flow and vascular CO2 reactivity observed in the younger normals was disturbed in the older normals. The data show a hyperfrontal distribution of regional cerebral blood flow in normal subjects that diminishes during the fifth and sixth decades, along with a distribution of vascular CO2 reactivity in younger normal subjects that is not homogeneous throughout the frontoparietal regions.(ABSTRACT TRUNCATED AT 250 WORDS)
Effect of uridine 5'-diphosphate on cryogenic brain edema in rabbits.
Authors: Yoshida S , Alksne J F , Seelig J M , Bailey M D , Moore S S , Kitamura K
Published: June 2011

This study was undertaken to examine the effect of uridine 5'-diphosphate, administered intravenously or intraperitoneally, on cold injury-induced brain edema in rabbits. Bolus injection or continuous intravenous infusion of uridine 5'-diphosphate 26 hours after a lesion was established had adverse effects, such as increased intracranial pressure and lowered systolic arterial blood pressure and cerebral perfusion pressure for approximately 10-29 minutes, but these parameters did not change appreciably from 29 minutes to 3 hours after administration. Intraperitoneally administered uridine 5'-diphosphate did not affect these parameters appreciably during 3 hours. Thus, the intravenous administration of uridine 5'-diphosphate is harmful under neurosurgical conditions. In contrast, 10 mg/kg/day i.p. uridine 5'-diphosphate pretreatment and posttreatment, beginning 24 hours before and continuing until 24 hours after the insult, significantly reduced neurologic abnormalities, Evans blue extravasation, water content in the injured gray matter, and intracranial pressure without affecting water content in the white matter. Intravenous dexamethasone pretreatment and posttreatment in this setting significantly reduced only neurologic abnormalities. However, there were no significant differences between intraperitoneal uridine 5'-diphosphate and intravenous dexamethasone effects on cold-injured brain.
Etiology of stroke in patients with Wernicke's aphasia.
Authors: Knepper L E , Biller J , Tranel D , Adams H P , Marsh E E
Published: June 2011

We reviewed 49 patients with Wernicke's aphasia resulting from a stroke. Their aphasia was classified on the basis of comprehensive neuropsychological testing. Wernicke's aphasia was more common in older patients and in men. Cerebral infarction occurred in 38 patients (78%) and intracerebral hemorrhage in seven (14%); the remaining four patients (8%) developed aphasia after surgery for aneurysmal subarachnoid hemorrhage. Embolic events were the most common etiology of Wernicke's aphasia in the 38 patients with cerebral infarction, with cardiac emboli in 40% and large-vessel atheroemboli from a carotid source in 16%. In patients with Wernicke's aphasia secondary to infarction, an embolic source should be sought. Patients with Wernicke's aphasia should have computed tomography to exclude intracerebral hemorrhage before institution of anticoagulant therapy.
Effect of nitroglycerin on cerebral circulation measured by transcranial Doppler and SPECT.
Authors: Dahl A , Russell D , Nyberg-Hansen R , Rootwelt K
Published: June 2011

We used a combination of transcranial Doppler ultrasonography and single-photon emission computed tomography to noninvasively assess changes in the diameter of the middle cerebral artery induced by sublingual nitroglycerin in 10 healthy subjects. Nitroglycerin reduced mean blood flow velocities without concurrently changing regional cerebral blood flow in the perfusion territory of this vessel. Our results strongly suggest that nitroglycerin causes vasodilatation of the basal intracranial arteries.
Fusiform aneurysm of the vertebrobasilar arterial system.
Authors: Echiverri H C , Rubino F A , Gupta S R , Gujrati M
Published: June 2011

We retrospectively evaluated the clinical features and therapeutic outcomes in 13 consecutive patients with the diagnosis of fusiform aneurysm of the vertebrobasilar system. Four patients (31%) presented with compressive symptoms and 10 (77%) with ischemic symptoms; one patient presented with both types of symptoms. No patient presented with rupture of the fusiform aneurysm. Based on the attending physician's choice, treatment included antiplatelet therapy in five patients, anticoagulation in seven, and no medication in one. Five patients died, four treated with antiplatelet agents and one not treated with any medication. The cause of death was progressive brainstem ischemia in three, sepsis in one, and gastrointestinal bleeding in one patient. All seven patients who received anticoagulants were alive, with no recurrence of symptoms or hemorrhagic complications after a mean follow-up period of 18 months. Based on previous and current series, we conclude that rupture of fusiform aneurysms is rare. Our results suggest a more favorable outcome in the management of these aneurysms with anticoagulation therapy to prevent progressive thrombosis and embolization.