bluuebunny/crossref_metadata_2025_split huggingface dataset:
Increased release of tumor necrosis factor-alpha into the cerebrospinal fluid and peripheral circulation of aged rats.
Authors: Sirén A L , Liu Y , Feuerstein G , Hallenbeck J M 
Published: June 2011

We earlier reported that risk factors for stroke prepare brain stem tissue for a modified Shwartzman reaction, including the development of ischemia and hemorrhage and the production of tumor necrosis factor-alpha, after a provocative dose of lipopolysaccharide. In the present study, we sought to determine whether blood and central nervous system cells of rats with the stroke risk factor of advanced age produce more proinflammatory and prothrombotic mediators than do those of young rats of the same strain.
Levels of tumor necrosis factor-alpha and platelet activating factor in the cerebrospinal fluid and tumor necrosis factor-alpha in the serum of 2-year-old and 16-week-old Sprague-Dawley rats were monitored before and after challenge with lipopolysaccharide.
No consistent tumor necrosis factor-alpha activity was found in the cerebrospinal fluid or blood of control animals. Intravenous administration of lipopolysaccharide (1.8 mg/kg) increased serum tumor necrosis factor-alpha levels but had no effect on tumor necrosis factor-alpha in the cerebrospinal fluid. Serum tumor necrosis factor-alpha increased much more in aged rats than in young rats. When lipopolysaccharide was injected intracerebroventricularly, tumor necrosis factor-alpha activity in cerebrospinal fluid increased significantly more in old rats than in young rats. Baseline levels of platelet activating factor in cerebrospinal fluid were significantly higher in old rats than in young rats, and the levels increased to a greater degree in aged rats on stimulation.
Rats with the stroke risk factor of advanced age respond to lipopolysaccharide with a more exuberant production of tumor necrosis factor-alpha and platelet activating factor than young rats of the same strain. These findings are consistent with our working hypothesis that perivascular cells are capable of exaggerated signaling of endothelium through cytokines such as tumor necrosis factor-alpha in animals with stroke risk factors. The effect of such signaling might be to prepare the endothelium of the local vascular segment for thrombosis or hemorrhage in accord with the local Shwartzman reaction paradigm.
Systemic giant cell arteritis and cerebellar infarction.
Authors: Mclean C A , Gonzales M F , Dowling J P 
Published: June 2011

Systemic giant cell arteritis causing cerebellar infarction due to intracranial arteritis of the anterior inferior cerebellar artery has not been previously reported. We report this infrequent occurrence and discuss the differential diagnosis.
An 85-year-old woman was admitted with a 2-week history of episodic ataxia, unilateral headaches, and vomiting. She had a history of atrial fibrillation and breast carcinoma. Her mental state was initially normal, and there were right-sided cerebellar signs. An ejection systolic murmur was heard, and peripheral pulses were palpable. A postmortem examination revealed cerebellar infarction due to giant cell arteritis of the anterior inferior cerebellar artery and basilar arteries. Systemic giant cell arteritis was also present.
Giant cell arteritis is a systemic disorder that can infrequently involve intracranial vessels, including the basilar, vertebral, and anterior cerebellar arteries. Cerebellar infarction secondary to the arteritis may occur. The distribution and size of intracranial vessel involvement is distinct from isolated cranial angiitis.
Arterial oxygen content and age are determinants of middle cerebral artery blood flow velocity.
Authors: Macko R F , Ameriso S F , Akmal M , Paganini-Hill A , Mohler J G , Massry S G , Meiselman H J , Fisher M 
Published: June 2011

Transcranial Doppler blood flow velocities are inversely related to age and hematocrit, but the relative importance of age, oxygenation, and hemorheological factors has not previously been examined. We evaluated the relative contributions of these factors to middle cerebral artery blood flow velocity in adults with chronic renal failure, a population subject to significant fluctuations in hematologic profile.
Twenty-six subjects were studied, with arterial shunt blood sampled at the time of transcranial Doppler before dialysis. Twenty subjects from the original cohort were studied twice to examine the effects of intraindividual changes in blood oxygenation and rheology on Doppler velocities.
Age (r = -.61, P < .001), high-shear viscosity (r = -.46, P < .02), and arterial oxygen content (r = -.44, P < .05) were all inversely related to middle cerebral artery blood flow velocity. Age was the strongest velocity predictor, accounting for 37% of variance by simple regression analysis. Intraindividual change in arterial oxygen content explained most (54%) of the middle cerebral artery blood flow velocity variation between studies (r = -.74, P < .001). Multiple regression analysis showed that inclusion of additional variables could not account for more velocity variation than change in arterial oxygen content alone.
In this population, age and arterial oxygen content were the most important determinants of interindividual middle cerebral artery blood flow velocity variance and intraindividual middle cerebral artery blood flow velocity variation, respectively.
Volume of intracerebral hemorrhage. A powerful and easy-to-use predictor of 30-day mortality.
Authors: Broderick J P , Brott T G , Duldner J E , Tomsick T , Huster G 
Published: June 2011

The aim of this study was to determine the 30-day mortality and morbidity of intracerebral hemorrhage in a large metropolitan population and to determine the most important predictors of 30-day outcome.
We reviewed the medical records and computed tomographic films for all cases of spontaneous intracerebral hemorrhage in Greater Cincinnati during 1988. Independent predictors of 30-day mortality were determined using univariate and multivariate statistical analyses.
The 30-day mortality for the 188 cases of intracerebral hemorrhage was 44%, with half of deaths occurring within the first 2 days of onset. Volume of intracerebral hemorrhage was the strongest predictor of 30-day mortality for all locations of intracerebral hemorrhage. Using three categories of parenchymal hemorrhage volume (0 to 29 cm3, 30 to 60 cm3, and 61 cm3 or more), calculated by a quick and easy-to-use ellipsoid method, and two categories of the Glasgow Coma Scale (9 or more and 8 or less), 30-day mortality was predicted correctly with a sensitivity of 96% and a specificity of 98%. Patients with a parenchymal hemorrhage volume of 60 cm3 or more on their initial computed tomogram and a Glasgow Coma Scale score of 8 or less had a predicted 30-day mortality of 91%. Patients with a volume of less than 30 cm3 and a Glasgow Coma Scale score of 9 or more had a predicted 30-day mortality of 19%. Only one of the 71 patients with a volume of parenchymal hemorrhage of 30 cm3 or more could function independently at 30 days.
Volume of intracerebral hemorrhage, in combination with the initial Glasgow Coma Scale score, is a powerful and easy-to-use predictor of 30-day mortality and morbidity in patients with spontaneous intracerebral hemorrhage.
Does low-dose acetylsalicylic acid prevent stroke after carotid surgery? A double-blind, placebo-controlled randomized trial.
Authors: Lindblad B , Persson N H , Takolander R , Bergqvist D 
Published: June 2011

The aim of this randomized double-blind, placebo-controlled trial was to evaluate whether neurological deficits could be prevented with low-dose acetylsalicylic acid (ASA) as an adjunct to carotid endarterectomy.
A total of 232 patients were randomized to two groups, 75 mg/d ASA starting preoperatively and continued for 6 months (n = 117) or placebo (identical tablets) (n = 115). The patients were followed up regularly for 1 year.
The groups were well matched regarding laboratory data and indication for operation. The number of patients with intraoperative or postoperative stroke without complete recovery within 1 week were 0 and 2 at 30 days and 6 months, respectively, in the ASA group, compared with 7 and 11 in the placebo group (P = .01). Including all neurological events within 6 months, this was found in 15 patients in the ASA group compared with 24 in the placebo group (P = .12). Mortality was 0.8% and 3.4% at 30 days and 6 months, respectively, in the ASA group. In the placebo group, the corresponding figures were 4.3% and 6.0%, respectively (P = .12). The intraoperative bleeding did not differ between the groups nor did the number of reoperations due to bleeding or other complications related to pharmacology.
This study indicates that low-dose ASA (75 mg/d) reduces the number of postoperative strokes without complete recovery within 1 week. Overall neurological events are insignificantly reduced, as also mortality. The use of low-dose ASA (75 mg) seems safe and effective in reducing cerebrovascular events after carotid endarterectomy.
Hyperglycemia in the acute phase of stroke is not caused by stress.
Authors: van Kooten F , Hoogerbrugge N , Naarding P , Koudstaal P J 
Published: June 2011

Hyperglycemia in the acute phase of stroke is associated with poor outcome. Whether hyperglycemia in nondiabetic stroke patients is caused by stress is controversial.
We studied glucose levels and glycosylated hemoglobin in 91 consecutive patients with acute stroke admitted within 24 hours after onset of symptoms. In 27 unselected patients we also measured catecholamines on days 1 and 3 after onset.
Hyperglycemia was found in 39 (43%) of the patients, 55% of whom either had diabetes mellitus or latent diabetes; the others had idiopathic hyperglycemia. Norepinephrine levels were associated with the severity of the stroke (P = .005) and with hypertension (P = .03) but not with glucose levels, irrespective of whether or not the patients had diabetes.
We conclude that hyperglycemia in the acute phase of stroke cannot be explained by increased stress.
The Frenchay Activities Index. Assessment of functional status in stroke patients.
Authors: Schuling J , de Haan R , Limburg M , Groenier K H 
Published: June 2011

Assessment of functional status in stroke patients is of major importance in both clinical practice and outcome studies. The Frenchay Activities Index has been developed specifically for measuring disability and handicap in stroke patients. The purpose of the study was to evaluate the metric properties of this instrument and to obtain normal values in a group of unselected elderly subjects.
The Frenchay Activities Index was tested in a group of stroke patients and a group of unselected subjects aged 65 or older. The functional status of the stroke patients was measured 26 weeks after stroke. Their prestroke status was registered retrospectively. Reliability and validity of the instrument were assessed.
The mean scores in the prestroke, poststroke, and control group demonstrated differences in functional status. The reliability of unweighted scores (range of Cronbach's alpha-coefficients, 0.78 to 0.87) was sufficient. The construct validity was supported by meaningful correlations between the Frenchay Activities Index and scores on the Barthel Index and Sickness Impact Profile. Principal-components analysis indicated that the Frenchay Activities Index showed two traits: instrumental disability and some aspects of handicap. The reliability of the instrument could be improved by deleting two items and by creating two subscale scores: domestic and outdoors activities.
The Frenchay Activities Index is a useful stroke-specific instrument to assess functional status. Completion of the questionnaire is easy and takes only a few minutes. Currently, the instrument is suitable for use in patient care and cross-sectional, descriptive studies.
Effect of low-intensity warfarin anticoagulation on level of activity of the hemostatic system in patients with atrial fibrillation. BAATAF Investigators.
Authors: Kistler J P , Singer D E , Millenson M M , Bauer K A , Gress D R , Barzegar S , Hughes R A , Sheehan M A , Maraventano S W , Oertel L B 
Published: June 2011

The Boston Area Anticoagulation Trial for Atrial Fibrillation (BAATAF) demonstrated that low-intensity warfarin anticoagulation can, with safety, sharply reduce the rate of stroke in patients with nonvalvular atrial fibrillation. The beneficial effect of warfarin was presumably related to a decrease in clot formation in the cardiac atria and subsequent embolization.
To assess the effect of warfarin therapy on in vivo clotting in patients in the BAATAF, we measured the plasma level of prothrombin activation fragment F1+2. One sample was obtained from 125 patients from the BAATAF; 62 were taking warfarin and 63 were not taking warfarin (control group).
The warfarin group had a 71% lower mean F1+2 level than the control group (mean F1+2 of 1.57 nmol/L in the control group compared with a mean of 0.46 nmol/L in the warfarin group; P < .001). F1+2 levels were higher in older subjects but were consistently lower in the warfarin group at all ages. Fifty-two percent of patients in the control group were taking chronic aspirin therapy at the time their F1+2 level was measured. Control patients taking aspirin had F1+2 levels very similar to control patients not taking aspirin (mean of 1.52 nmol/L for control patients on aspirin compared with 1.64 nmol/L for control patients off aspirin; P > .1).
We conclude that prothrombin activation was significantly suppressed in vivo by warfarin but not aspirin among patients in the BAATAF. These findings correlate with the marked reduction in ischemic stroke noted among patients in the warfarin treatment group observed in the BAATAF.
Estimation of arterial stiffness, compliance, and distensibility from M-mode ultrasound measurements of the common carotid artery.
Authors: Gamble G , Zorn J , Sanders G , MacMahon S , Sharpe N 
Published: June 2011

Arterial stiffness may indicate early vascular changes that predispose to the development of major vascular disease. The repeatability of a variety of indices of arterial stiffness calculated from a standard carotid arterial M-mode ultrasound image was investigated.
Twenty-six asymptomatic normal subjects were imaged and had blood pressure recordings on each of two separate occasions at least 1 day apart. Using a computer-assisted method, the maximum and minimum internal diameter and average wall thickness of the right common carotid artery were measured over several cardiac cycles, and the following indices of arterial stiffness and distensibility (compliance) were derived: the pressure-strain elastic modulus (Ep), Young's modulus (E), cross-sectional compliance (CC), and the distensibility coefficient (DC).
The repeatability of these measures, expressed as coefficients of variation, was as follows: Ep, 18%; E, 24%; CC, 14%; and DC, 13%. In another group of 20 subjects, the coefficient of variation for repeat examination by different sonographers was Ep, 19%; E, 20%; CC, 14%; and DC, 17% and for the one sonographer using two ultrasound machines was Ep, 13%; E, 13%; CC, 11%; and DC, 13%. These values indicate a moderate level of repeatability. In a univariate analysis each of these indices was significantly related to increasing age (Ep = 1.0 + 12.9 x AGE, r = .80; E = 314.5 + 13.9 x AGE, r = .48; CC = 22.6-0.26 x AGE, r = -.63; DC = 64.0-0.65 x AGE, r = -.78) but not to wall thickness (all P > .47). Using multiple regression techniques to adjust for age, wall thickness is a significant predictor of distensibility (P = .017), cross-sectional compliance (P < .001), and the pressure-strain elastic modulus (P = .019). Because Young's modulus is calculated from wall thickness, it could not be included in the multivariate analysis.
We conclude that estimates of carotid artery distensibility and cross-sectional compliance derived from M-mode ultrasound recordings are moderately repeatable and may provide useful additional end points for trials of atherosclerotic progression.
The perfluorocarbon fluoromethyloadamantane offers cerebral protection in a model of isovolemic hemodilution in rabbits.
Authors: Sakas D E , Crowell R M , Kim K , Korosue K , Zervas N T 
Published: June 2011

Perfluorocarbons (PFCs) are considered promising cerebral protection agents because they could combine the beneficial effects of decreased blood viscosity with enhanced oxygen-carrying capacity and oxygen tissue delivery, but trials of PFCs as hemodilutants have been very limited. We evaluated fluoromethyloadamantane (FMA), a new perfluorocarbon compound, as an isovolemic hemodilutant and compared it with low-molecular-weight dextran 40 (D40) and a control group.
Through a transorbital craniectomy, the internal carotid, anterior, and middle cerebral arteries were coagulated to create a cerebral infarction in anesthetized, mechanically ventilated rabbits. No other experimental procedure was performed in control animals. In the two other groups, hemodilution was commenced 30 minutes after the arterial occlusion with either D40 or FMA. Hemodynamic parameters and brain and systemic temperature were monitored throughout the experiments. All animals were killed 6 hours after the arterial occlusion.
Hemodynamic and metabolic parameters and blood oxygen content were not affected by the infusion of either FMA or D40. Brain and systemic temperature remained constant. The ratio of infarct volume to the hemispheric volume was 19.6 +/- 3.7% in the FMA group (n = 17), 19.9 +/- 4.6% in the D40 group (n = 16), and 40.3 +/- 5.7% in the control group (n = 17). The difference in infarct volume of both FMA and D40 animals compared with controls was statistically significant (P < .01) when tested with Student's t test. There was no significant difference between FMA and D40 groups.
These results suggest that FMA has cerebral protective properties and should be purified, optimized, and further tested experimentally to develop a stable, efficient, and safe oxygen carrier, potentially suitable for clinical trials.
Stroke prevention. An opportunity for efficient utilization of health care resources during the coming decade.
Authors: Gorelick P B 
Published: June 2011

Stroke is unique among neurological diseases, since it has a high prevalence and burden of illness, high economic cost, and is preventable. Epidemiological approaches to stroke prevention include the "high-risk" and "mass" approaches. In this review we discuss these preventive strategies, target host and discretionary risk factors that are amenable to these measures, and discuss potential cost savings.
Projected numbers of strokes prevented for specific stroke risk factors were estimated by using the population-attributable risk estimation for hypertension, cigarette smoking, atrial fibrillation, and heavy alcohol consumption. The projected numbers of strokes that could be prevented were substantial and highest for hypertension and cigarette smoking. Projected yearly cost of stroke associated with these two treatable factors was also substantial.
The prevention of stroke can be accomplished by the high-risk or mass approach or a combination of these approaches. The high-risk approach prevents strokes but is also expensive. The mass approach may be more cost-effective, which could lead to substantial savings, but this needs to be investigated.
Blinded-reader comparison of magnetic resonance angiography and duplex ultrasonography for carotid artery bifurcation stenosis.
Authors: Mittl R L , Broderick M , Carpenter J P , Goldberg H I , Listerud J , Mishkin M M , Berkowitz H D , Atlas S W 
Published: June 2011

We compared two-dimensional time-of-flight magnetic resonance angiography (MRA) and duplex ultrasonography with arteriography for the detection of 70% to 99% stenoses at the carotid artery bifurcation (ie, surgical disease according to findings of the North American Carotid Endarterectomy Trial).
Three blinded readers independently measured stenoses on MRA in 73 vessels from 38 patients. Duplex ultrasonography was available in 66 vessels from 35 of these patients, and blinded reading was performed by one reader. Comparison was made to arteriography.
Magnetic resonance angiography demonstrated a sensitivity of 92.4%, specificity of 74.5%, and negative predictive value of 95.8% for 70% to 99% stenoses. Interobserver agreement was high (kappa = 0.91). Absence of signal at stenoses with evidence of distal flow usually, but not always, corresponded to surgical disease. Duplex ultrasonography demonstrated a sensitivity of 81.0%, specificity of 82.2%, and negative predictive value of 90.2% for surgical disease. There was no significant difference between MRA and duplex ultrasonography for the sensitivity or specificity in detecting 70% to 99% stenoses (P > .1, exact form of the McNemar test). MRA had no false positives or false negatives for complete occlusions of the carotid artery, whereas duplex ultrasonography missed one occlusion and falsely called two patent vessels occluded. In seven cases, both MRA and duplex ultrasonography overestimated stenoses to miscategorize them as surgical disease.
Although the sensitivity and specificity of MRA and duplex ultrasonography are not significantly different for distinguishing surgical and nonsurgical degrees of stenosis at the carotid bifurcation, MRA has some advantages that may make it the screening test of choice. Concordant MRA and duplex ultrasonography for surgical disease does not necessarily obviate the need for catheter arteriography.
Stroke risk profile: adjustment for antihypertensive medication. The Framingham Study.
Authors: D'Agostino R B , Wolf P A , Belanger A J , Kannel W B 
Published: June 2011

We sought to modify existing sex-specific health risk appraisal functions (profile functions) for the prediction of first stroke that better assess the effects of the use of antihypertensive medication.
Health risk appraisal functions were previously developed from the Framingham Study cohort. These functions were Cox proportional hazards regression models relating age, systolic blood pressure, diabetes mellitus, cigarette smoking, prior cardiovascular disease, atrial fibrillation, left ventricular hypertrophy by electrocardiogram, and the use of antihypertensive medication to the occurrence of stroke. Closer examination of the data indicated that antihypertensive therapy effect is present only for systolic blood pressures between 110 and 200 mm Hg. Adjustments to the regressions to better fit the observed data were developed and tested for statistical significance and goodness-of-fit of the model residuals.
Modified functions more consistent with the data were developed, and, from these, tables to evaluate 10-year risk of first stroke were computed.
The stroke profile can be used for evaluation of the risk of stroke and suggestion of risk factor modification to reduce risk. The effect of antihypertensive therapy in the evaluation of stroke risk can now be better evaluated.