bluuebunny/crossref_metadata_2025_split huggingface dataset:
Blood flow velocity and vasomotor reactivity in patients with arteriovenous malformations. A transcranial Doppler study.
Authors: Diehl R R , Henkes H , Nahser H C , Kühne D , Berlit P 
Published: June 2011

A large percentage of patients with a cerebral arteriovenous malformation (AVM) show focal neurological signs or have a history of intracranial hemorrhage. The present study used transcranial Doppler sonography to assess the clinical significance of hemodynamic disturbances in the intracranial arteries of patients with an AVM.
Eighteen patients with untreated AVMs were examined clinically, angiographically, and with transcranial Doppler sonography (blood flow velocity measurement and vasomotor reactivity in all main intracranial arteries).
A pathological increase in blood flow velocity (57.6%) and a decrease in vasomotor reactivity (72.7%) were frequently found in AVM feeding arteries. Vasomotor reactivity was also reduced in several nonfeeding arteries both ipsilateral (53.3%) and contralateral (30.8%) to the AVM. AVM size was a poor predictor of pathological transcranial Doppler results. Vasomotor reactivity of arteries ipsilateral to an AVM in patients with a history of hemorrhage was significantly higher (2.10 +/- 1.66% per mm Hg; mean +/- SD) than in patients with no history of bleeding (1.12 +/- 1.48% per mm Hg; P < .05). In patients with focal neurological signs but no history of hemorrhage, the percentage of arteries ipsilateral (100%) and contralateral (63.6%) to an AVM showing a pathological vasomotor reactivity was significantly larger than in nonhemorrhagic patients without focal signs (66.7% and 22.2%, respectively; both P < .05).
Our results suggest two distinct relations between transcranial Doppler results and clinical findings: (1) Relatively normal vasomotor reactivity values in arteries ipsilateral to an AVM indicate a high-pressure AVM with an increased risk of hemorrhage. (2) A strongly pathological vasomotor reactivity in arteries ipsilateral and contralateral to an AVM indicates a low-pressure AVM with a higher prevalence of hemodynamically induced neurological signs.
Prognosis after transient ischemic attack and ischemic stroke in young adults.
Authors: Ferro J M , Crespo M 
Published: June 2011

We undertook this study to describe the risk of stroke recurrence and functional and occupational status in the long-term follow-up of young adults with ischemic strokes and to identify possible predictors for stroke recurrence, disability, and working status.
A cohort of 215 patients aged < or = 45 years with ischemic cerebral events (43 transient ischemic attacks, 135 minor strokes, 37 major strokes), evaluated at our institution from May 1985 through March 1992, was followed for a mean of 43.1 months (SD, 39.7 months; range, 1 to 228 months). Information on death and recurrent cerebral vascular events, functional disability (Rankin Scale), retirement, and working status was obtained from direct observation, mail questionnaire, and telephone interviews.
Four patients (2%) with major strokes died acutely. Information on stroke recurrence and disability was available for 184 (87%) of the survivors and on retirement and working status for 140 (67%) of the patients. Two patients died from cancer. Seven transient ischemic attacks and eight strokes (two hemorrhagic) occurred during follow-up. Patients with strokes of unknown cause experienced no recurrent strokes, contrasting with two deaths and eight strokes in those whose stroke cause was identified (difference between proportions: 8%; 95% confidence interval, 3 to 13). Eighty-eight patients had a complete recovery, and only 21 were disabled (Rankin grades 4 or 5). Logistic regression analysis identified the severity of the initial stroke (Rankin grade > 3) as the only significant predictor of disability (odds ratio, 10.7; 95% confidence interval, 3.7 to 30.6). Of the survivors, 73% were working, and only 18% were retired. Disability at follow-up was the best (but nonsignificant) predictor of retirement (odds ratio, 1.6; 95% confidence interval, 0.8 to 3.4).
Ischemic stroke in young adults has a low acute mortality and few recurrences, more so if the cause is not identified. The majority of patients return to an active professional life. Severity of the initial stroke is the major predictor of independence. The relation between disability and return to work or retirement is less clear.
Definition of initial grading, specific events, and overall outcome in patients with aneurysmal subarachnoid hemorrhage. A survey.
Authors: van Gijn J , Bromberg J E , Lindsay K W , Hasan D , Vermeulen M 
Published: June 2011

Scientific communication in medicine can be effective only if reports are based on unequivocal criteria for clinical conditions or specific diagnoses.
We reviewed all articles about subarachnoid hemorrhage published in nine neurosurgical or neurological journals from 1985 through 1992 and assessed the presence and the precision of definitions used for reporting the initial grade, the specific complications of rebleeding, delayed cerebral ischemia, and hydrocephalus, and the overall outcome. We identified 184 articles reporting direct observations in at least 10 patients on one or more of these conditions.
Of 161 articles reporting the initial condition, only 19% used an unequivocal grading system (World Federation of Neurological Surgeons Scale or Glasgow Coma Scale); this proportion did not increase after 1988, when the World Federation of Neurological Surgeons Scale was introduced. The specific outcome events of rebleeding, ischemia, and hydrocephalus (283 instances) were sufficiently defined in only 31% of instances, incompletely in 22%, and not at all in 47%. The proportions were similar when the results were analyzed according to the type of complication, the year of publication, or per study. The four exclusively neurosurgical journals featured suitable definitions for any of the three outcome events in 20% of 209 instances, whereas the five mainly neurological journals published fewer articles about subarachnoid hemorrhage (74 instances of outcome events) but more often with precise criteria (65%). Overall outcome was adequately reported in 63% of all articles, with an increase over the years (54% in 1985 through 1988, 71% in 1989 through 1992).
Reports about subarachnoid hemorrhage require closer scrutiny before publication to ascertain whether the conclusions about specific outcome events are based on unequivocal criteria.
The cold hemiplegic arm.
Authors: Wanklyn P , Ilsley D W , Greenstein D , Hampton I F , Roper T A , Kester R C , Mulley G P 
Published: June 2011

Vasomotor changes occur in the arm after hemiplegic stroke. Previous studies have provided conflicting results, with most showing an increase in skin temperature of the hemiplegic arm. However, a number of patients complain of distressing coldness of the hemiplegic arm.
Eleven patients with symptomatic coldness and 10 patients with hemiplegia but no coldness were recruited. The severity of the symptom of coldness was compared by questionnaire with other common symptoms after stroke. A thermographic camera was used to record the finger skin temperature response to cold stress. Blood flow to both hands was also measured simultaneously by means of two plethysmographs. In all patients there were no symptoms in the unaffected arm, and this was used as a control.
The symptom of coldness rated highly compared with other symptoms. In the symptomatic group the finger temperature on the hemiplegic side was lower at rest (median difference at rest, 0.65 degrees C; P < .0001) and at all times after cold stress. In the asymptomatic group the fingers on the hemiplegic side were colder at rest and after initial cooling (median temperature difference, 0.2 degrees C) but at no other time. Hand blood flow on the hemiplegic side was also decreased in the symptomatic group by 35%. This was not seen in the asymptomatic group.
Coldness of the hand may be a severe and distressing symptom in some patients after hemiplegia. Symptomatic patients have lower finger skin temperatures at rest and after standard cold stress. These symptomatic patients also had reduced blood flow to the hemiplegic hand.
Role of angiogenesis in patients with cerebral ischemic stroke.
Authors: Krupinski J , Kaluza J , Kumar P , Kumar S , Wang J M 
Published: June 2011

Stroke is one of the most common causes of mortality and morbidity in the Western world. It results from the occlusion of a cerebral artery followed by severe disturbances in blood supply through microvessels to brain tissue. Despite an extensive literature its pathophysiology is poorly understood, and this has severely impeded the logical development of therapy.
Brains were obtained from 10 patients aged 46 to 85 years with survival times of 5 to 92 days after their stroke. Infarcted areas and representative control tissues from the contralateral uninvolved brain hemisphere were collected. Microvessel density was measured microscopically. A total of 6520 microvessels were scored in 10,801 areas. The level of activation of the endothelial cells was studied by immunohistochemistry using three monoclonal antibodies, viz, E-9, raised against activated endothelial cells; IG11, recognizing vascular cell adhesion molecule-1; and anti-proliferating cell nuclear antigen. Angiogenic activity in tissue extracts was examined using an in vivo chicken chorioallantoic membrane assay.
There was a statistically significant increase in the number of microvessels (Wilcoxon log-rank test; P < or = .01) in 9 of 10 infarcted brain tissues when compared with their contralateral normal hemisphere. In these patients the higher blood vessel counts correlated with longer survival, as ascertained by Spearman's p analysis (P < .02). The number of microvessels filled with blood cells was significantly lower in the infarcted hemispheres (P < .01). In contrast, statistically significant increased numbers of empty microvessels occurred in infarcted tissues compared with the contralateral hemisphere. Monoclonal antibody E-9 reacted weakly with normal-brain vascular endothelial cells; anti-proliferating cell nuclear antigen and IG11 were virtually negative. All three antibodies strongly stained the blood vessels of stroke tissues. The stroke tissues contained angiogenic activity, as shown by the induction of new blood vessels in a chorioallantoic membrane assay.
We have shown that stroke causes active angiogenesis that is more developed in the penumbra. Further experiments are needed to determine if this angiogenesis has beneficial effect.
Preischemic hyperglycemia leads to delayed postischemic hyperthermia.
Authors: Uchino H , Lundgren J , Smith M L , Siesjö B K 
Published: June 2011

Temperature alterations are known to influence the outcome of transient ischemia, even when instituted in the postischemic period. Since preischemic hyperglycemia aggravates ischemic brain damage, the question of whether hyperglycemic animals become hyperthermic arose. To explore this possibility, we measured body temperature telemetrically in normoglycemic and hyperglycemic rats subjected to 10 minutes of forebrain ischemia at a body (and brain) temperature of 37 degrees C.
Isoflurane-anesthetized animals were subjected to 10 minutes of forebrain ischemia under normoglycemic or hyperglycemic conditions. Temperature changes after ischemia were measured by means of a telemetric temperature coil.
In normoglycemic animals, temperature decreased to 35.6 +/- 1.1 degrees C (mean +/- SD) during the first 4 hours of recovery, after which it gradually increased to normal values (38 degrees C). Hyperglycemic animals behaved differently in that they remained normothermic for approximately 10 hours during recovery and later became hyperthermic, with core temperatures rising above 39 degrees C. The rise in temperature was not due to the osmotic load of the glucose administered because infusion of mannitol, which gave a comparable increase in plasma osmolality, failed to cause delayed postischemic hyperthermia. Excessive hypercapnia during ischemia in normoglycemic animals, which produces cerebral acidosis of a magnitude similar to that of hyperglycemia and is known to aggravate ischemic lesions, likewise failed to induce hyperthermia. When post-ischemic seizures ensued in hyperglycemic subjects, temperature was 39.8 +/- 0.6 degrees C. Animals with seizures invariably died. To evaluate the influence of postischemic hyperthermia on the outcome, an additional series of experiments was performed in which delayed hyperthermia was avoided by gentle cooling (n = 6) or by acetaminophen administration (n = 5). Although these procedures prevented delayed hyperthermia, they neither blocked seizure induction nor affected the fatal outcome. Postischemic seizures developed when the core temperatures of animals were 37.9 +/- 0.1 degrees C and 37.8 +/- 0.2 degrees C in the cooled and acetaminophen-treated groups, respectively.
The results suggest that both delayed hyperthermia and delayed seizures in hyperglycemic animals are caused by the aggravated damage incurred by these animals during or immediately after the ischemic insult.
Experimental Brain Prosthesis for Stroke
Authors: Pinneo L. R. , Kaplan J. N. , Elpel E. A. , Reynolds P. C. , GLICK J. H. 
Published: June 2011

Electrical control of motor behavior by programmed electrical stimulation of the brain has been described. Such programmed brain stimulation is referred to as a "brain prosthesis," meaning, in effect, "artificial brain."
Areas in the brain which related to the production of elementary movements were located. From these preliminary experiments it was evident that programmed stimulation of the brain at sites typically unaffected by stroke could produce a "purposive" sequence of motor behaviors.
Monkeys were made monoplegic by surgical (two-stage) resection of appropriate cortical and subcortical regions. After recovery electrodes were implanted in the brain. This technique is described.
The electrodes are linked to a multiple-electrode programmable brain stimulator. The stimulator and computer programming make it possible to specify which electro-stimulators are to be turned on, and strength and duration of current to produce a pattern of complex motor function.
Programs of stimulation, which cause the paralyzed limb to reach out, grasp an object (such as food), and bring the object rapidly and smoothly to the mouth, have been written. The ultimate question of applicability of this model in humans remains to be studied.
Relationship of Serial Measurements of Cerebral Hemodynamics to Prognosis in Patients with Hypertension and Cerebrovascular Disease
Authors: Yamaoka Saburo , Takagi Yasuyuki , Okada Toshihiro , Saito Yoshio 
Published: June 2011

Baseline and follow-up measurements of cerebral hemodynamics were performed in hypertensive patients by the N
2
O method with a certain time interval. A tendency for some decrease in the CBF was noted, but the difference was not statistically significant.

Twelve hypertensive patients suffered from a stroke during the period of observation. The CBF values prior to the stroke varied so widely that there was no predictive value from these measurements.
The decrease in CBF in a mild case of cerebral infarction is slight and is followed by little fluctuation. The decrease in a case of moderate severity is marked but returns to normal in two to five months. Clinically severe cases of infarction and hemorrhage are also characterized by a marked decrease in CBF, but this decrease of infarcted cases may be irreversible.
A higher incidence of recurrent infarction is noted in those patients in whom recovery of CBF following a stroke is poorest. This is most apparent in those patients suffering a recurrence within one year.
Pathophysiological Responses to Acute Cerebral Ischemia in the Gerbil
Authors: Wexler Bernard C. , Wexler Nancy C. , Conatser Dilmon 
Published: June 2011

The left carotid artery of healthy, male gerbils was surgically ligated to induce a state of cerebral ischemia. The animals were sacrificed two, four, six, 12, 24 and 48 hours postligation to determine whether the induced cerebral ischemia would be reflected by changes in blood chemistry. The gerbil, unlike the rat, has a well-defined circle of Willis and cerebral arterial branches which resemble the arrangement of cerebral arteries found in man.
The gerbils withstood the induced cerebral ischemia relatively well with few overt signs of cerebral damage, e.g., muscular paralysis, and a low mortality rate. However, intense lipid mobilization accompanied by depletion of peripheral adipose tissue sites and fatty infiltration of the liver developed very promptly. Marked cerebral edema and definitive foci of cerebral infarction occurred in both the frontal and medial lobes of the brain. The adrenal cortices of the gerbil were markedly depleted of lipid concomitant with severe thymus gland involution indicative of intense corticosteroid release.
The serum enzymes, creatine phosphokinase and glutamic oxaloacetic transaminase, both rose promptly, indicating cerebral and hepatic damage respectively. Lipids, i.e., triglycerides, free fatty acids and total cholesterol, all rose promptly and to significantly above-normal levels and remained super-normal throughout the 48-hour course of the experiment. Concomitant with the hyperlipidemia and other metabolic changes there were definite hyperglycemia and elevation of BUN levels in a brisk response to the induced, acute cerebral ischemia. The gerbil adrenal gland produces hydrocortisone predominantly. Blood levels of hydrocortisone rose quickly to super-normal levels in response to the stress of cerebral ischemia but fell to significantly below-normal levels 24 and 48 hours after carotid artery ligation. These findings demonstrate that acute cerebral ischemia constitutes a severe stress in the gerbil which is reflected, almost quantitatively, by temporal changes in such blood constituents as enzymes, lipids, glucose, and adrenal stress hormones.
Validation of Jugular Venous Flow as an Index of Total Cerebral Blood Flow
Authors: Wilson Edwin M. , Halsey James H. , Vitek Jiri J. 
Published: June 2011

Values of total cerebral blood flow in man measured by the indicator dilution method are compared with values of total internal jugular venous flow measured by the thermal dilution method. Except in the case of an extremely labile cerebral hemodynamic state, the results agree within the accuracy of the two methods, suggesting that for the supine patient total internal jugular venous flow provides a good index of total cerebral flow.
The relatively short measurement time associated with nondiffusible indicators (dye or thermal dilution) facilitates detection of transient changes in total CBF or differential jugular flow that would tend to be averaged out with diffusible indicator methods.
A mathematical analysis of the potential errors in the computation of total flow using the average of bilateral jugular venous dilution curves from a unilateral internal carotid injection is presented. This error can be partially corrected if the ratio of flow in one internal jugular to total flow is known.
An analysis of potential computational errors under nonsteady state flow conditions (change in flow during the period between alternate carotid injections) is presented. Such flow changes can effect substantial errors in the computation of individual hemispheric or internal jugular flow and smaller errors in the computation of total flow.
Spontaneous Dissecting Aneurysm of the Internal Carotid Artery
Authors: OJEMANN ROBERT G. , FISHER C. MILLER , RICH J. CHARLES 
Published: June 2011

A case of spontaneous dissection of the internal carotid artery is presented and the ten other reported cases are reviewed. It is most common in males aged 35 to 41 years. Of eight patients with neurological symptoms, two had transient hemiplegia and five of six first seen with a severe neurological deficit had prodromal symptoms. Angiography revealed a typical "string sign." A method of surgical treatment is illustrated. The importance of emergency angiography and surgery in patients with acute onset of progressive symptoms of cerebral vascular disease is emphasized by this case.
The surgical specimen was studied pathologically by serial section. At its origin the dissection measured 3 mm in width and 0.3 mm in length. Proximally the dissection was in the media but distally it lay at the medial-adventitial interface. There was no evidence of cystic medial necrosis but the muscle and elastic tissue of the media had a disorganized arrangement.
Cerebral Arteriovenous Shunts Re-examined
Authors: Rowed David W. , Stark Violet J. , Hoffer Paul B. , Mullan Sean 
Published: June 2011

Cerebral arteriovenous (A-V) shunts have been described in some histological studies, but their existence has been denied in others. Previous attempts to detect the presence and amount of A-V shunting using radioactive microspheres have suggested that large amounts of blood could bypass cerebral capillaries in this fashion. A reappraisal seemed indicated.
The present study, using the radioactive microsphere technique, confined the injected spheres specifically to the cerebral circulation of a nonhuman primate. The conclusion of this study is that structural, noncapillary A-V shunting definitely occurs, but is very small and variable in amount.
The implications of this finding in relation to previous studies and to the clinical phenomena of red cerebral veins and early venous filling are discussed.
Lactate in the Cerebrospinal Fluid and Pressure-Flow Relationships in Canine Cerebral Circulation
Authors: IWABUCHI TAKAYUKI , WATANABE KATSUHIRO , KUTSUZAWA TAKASHI , IKEDA KYUHEI , NAKAMURA TAKASHI 
Published: June 2011

In 11 dogs, lactate and pH in the cerebrospinal fluid and in the arterial and the venous blood were measured during stepwise reductions of the arterial blood pressure by controlled bleeding. Increase in lactate and decrease in pH of the cerebrospinal fluid occurred with lowering of the mean arterial blood pressure even within the pressure ranges of 110 to 50 mm Hg, where autoregulation was fairly observed. Reductions of the blood pressure by 20 to 40 mm Hg led to a significant increase in lactate, and reductions by 60 mm Hg led to a significant decrease in pH of the cerebrospinal fluid.
The relation of decrease in pH and increase in lactate was linear, suggesting that lactacidosis occurred. In the arterial and the venous blood, a marked increase in lactate and decrease in pH also were observed. Lactate concentrations of the cerebral venous blood were significantly higher than those of the arterial blood until the arterial blood pressure had been reduced below 70 mm Hg. Therefore, it was suggested that increase in lactate of the cerebrospinal fluid might be attributed solely to increase in lactate of the brain tissue, so far as the blood pressure was not lowered below 70 mm Hg at least. The possibility of participation of the cerebrospinal fluid lactacidosis in autoregulation of the cerebral blood flow was discussed.
Stroke and Blood Coagulation
Authors: TODD MARGARET , MCDEVITT ELLEN , MCDOWELL FLETCHER 
Published: June 2011

A study of the coagulation parameters of 87 normal controls (ages 50 to 80) were compared with those of 33 patients with thrombotic stroke and 55 patients with diabetes mellitus of the same age distribution.
There were no significant differences when tested for the influence of sex or age.
Twenty-seven tests of clotting were done on each specimen, a total of 4,725.

Significant differences were detected between normals versus patients with thrombotic stroke (fibrinogen level, glass clotting time, silicone clotting time, heparin tolerance, platelet count and retarded thromboplastin generation time BaSO
4
1:50 dilution) and between normals versus patients with diabetes (prothrombin time, silicone clotting time, platelet count, thromboplastin generation time and retarded thromboplastin generation time) when subjected to computer analysis. The clinical significance of these differences is not of practical value in the diagnosis or as a guide to therapy for stroke.