bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impairment of Speech Production Predicted by Lesion Load of the Left Arcuate Fasciculus
Authors: Marchina Sarah , Zhu Lin L. , Norton Andrea , Zipse Lauryn , Wan Catherine Y. , Schlaug Gottfried 
Published: July 2011

Background and Purpose—
Previous studies have suggested that patients' potential for poststroke language recovery is related to lesion size; however, lesion location may also be of importance, particularly when fiber tracts that are critical to the sensorimotor mapping of sounds for articulation (eg, the arcuate fasciculus) have been damaged. In this study, we tested the hypothesis that lesion loads of the arcuate fasciculus (ie, volume of arcuate fasciculus that is affected by a patient's lesion) and of 2 other tracts involved in language processing (the extreme capsule and the uncinate fasciculus) are inversely related to the severity of speech production impairments in patients with stroke with aphasia.

Methods—
Thirty patients with chronic stroke with residual impairments in speech production underwent high-resolution anatomic MRI and a battery of cognitive and language tests. Impairment was assessed using 3 functional measures of spontaneous speech (eg, rate, informativeness, and overall efficiency) as well as naming ability. To quantitatively analyze the relationship between impairment scores and lesion load along the 3 fiber tracts, we calculated tract–lesion overlap volumes for each patient using probabilistic maps of the tracts derived from diffusion tensor images of 10 age-matched healthy subjects.

Results—
Regression analyses showed that arcuate fasciculus lesion load, but not extreme capsule or uncinate fasciculus lesion load or overall lesion size, significantly predicted rate, informativeness, and overall efficiency of speech as well as naming ability.

Conclusions—
A new variable, arcuate fasciculus lesion load, complements established voxel-based lesion mapping techniques and, in the future, may potentially be used to estimate impairment and recovery potential after stroke and refine inclusion criteria for experimental rehabilitation programs.
Natural Vitamin E α-Tocotrienol Protects Against Ischemic Stroke by Induction of Multidrug Resistance-Associated Protein 1
Authors: Park Han-A , Kubicki Natalia , Gnyawali Surya , Chan Yuk Cheung , Roy Sashwati , Khanna Savita , Sen Chandan K. 
Published: July 2011

Background and Purpose—
α-Tocotrienol (TCT) represents the most potent neuroprotective form of natural vitamin E that is Generally Recognized As Safe certified by the U.S. Food and Drug Administration. This work addresses a novel molecular mechanism by which α-TCT may be protective against stroke in vivo. Elevation of intracellular oxidized glutathione (GSSG) triggers neural cell death. Multidrug resistance-associated protein 1 (MRP1), a key mediator of intracellular oxidized glutathione efflux from neural cells, may therefore possess neuroprotective functions.

Methods—
Stroke-dependent brain tissue damage was studied in MRP1-deficient mice and α-TCT-supplemented mice.

Results—
Elevated MRP1 expression was observed in glutamate-challenged primary cortical neuronal cells and in stroke-affected brain tissue. MRP1-deficient mice displayed larger stroke-induced lesions, recognizing a protective role of MRP1. In vitro, protection against glutamate-induced neurotoxicity by α-TCT was attenuated under conditions of MRP1 knockdown; this suggests the role of MRP1 in α-TCT-dependent neuroprotection. In vivo studies demonstrated that oral supplementation of α-TCT protected against murine stroke. MRP1 expression was elevated in the stroke-affected cortical tissue of α-TCT-supplemented mice. Efforts to elucidate the underlying mechanism identified MRP1 as a target of microRNA (miR)-199a-5p. In α-TCT-supplemented mice, miR-199a-5p was downregulated in stroke-affected brain tissue.

Conclusions—
This work recognizes MRP1 as a protective factor against stroke. Furthermore, findings of this study add a new dimension to the current understanding of the molecular bases of α-TCT neuroprotection in 2 ways: by identifying MRP1 as a α-TCT-sensitive target and by unveiling the general prospect that oral α-TCT may regulate miR expression in stroke-affected brain tissue.
Correlation of Inpatient and Outpatient Measures of Stroke Care Quality Within Veterans Health Administration Hospitals
Authors: Ross Joseph S. , Arling Greg , Ofner Susan , Roumie Christianne L. , Keyhani Salomeh , Williams Linda S. , Ordin Diana L. , Bravata Dawn M. 
Published: July 2011

Background and Purpose—
Quality of care delivered in the inpatient and ambulatory settings may be correlated within an integrated health system such as the Veterans Health Administration. We examined the correlation between stroke care quality at hospital discharge and within 6 months postdischarge.

Methods—
We conducted a cross-sectional hospital-level correlation analyses of chart-abstracted data for 3467 veterans discharged alive after an acute ischemic stroke from 108 Veterans Health Administration medical centers and 2380 veterans with postdischarge follow-up within 6 months in fiscal year 2007. Four risk-standardized processes of care represented discharge care quality: prescription of antithrombotic and antilipidmic therapy, anticoagulation for atrial fibrillation, and tobacco cessation counseling along with a composite measure of defect-free care. Five risk-standardized intermediate outcomes represented postdischarge care quality: achievement of blood pressure, low-density lipoprotein, international normalized ratio, and glycosylated hemoglobin target levels, and delivery of appropriate treatment for poststroke depression along with a composite measure of achieved outcomes.

Results—

Median risk-standardized composite rate of defect-free care at discharge was 79%. Median risk-standardized postdischarge rates of achieving goal were 56% for blood pressure, 36% for low-density lipoprotein, 41% for international normalized ratio, 40% for glycosylated hemoglobin, and 39% for depression management and the median risk-standardized composite 6-month outcome rate was 44%. The hospital composite rate of defect-free care at discharge was correlated with meeting the low-density lipoprotein goal (
r
=0.31;
P
=0.007) and depression management (
r
=0.27;
P
=0.03) goal but was not correlated with blood pressure, international normalized ratio, glycosylated hemoglobin goals, nor with the composite measure of achieved postdischarge outcomes (probability values >0.13).

Conclusions—
Hospital discharge care quality was not consistently correlated with ambulatory care quality.
Racial Disparities in Tissue Plasminogen Activator Treatment Rate for Stroke
Authors: Hsia Amie W. , Edwards Dorothy F. , Morgenstern Lewis B. , Wing Jeffrey J. , Brown Nina C. , Coles Regina , Loftin Sarah , Wein Andrea , Koslosky Sara S. , Fatima Sabiha , Sánchez Brisa N. , Fokar Ali , Gibbons M. Chris , Shara Nawar , Jayam-Trouth Annapurni , Kidwell Chelsea S. 
Published: July 2011

Background and Purpose—
Some prior studies have shown that racial disparities exist in intravenous tissue plasminogen activator (tPA) use for acute ischemic stroke. We sought to determine whether race was associated with tPA treatment for stroke in a predominantly black urban population.

Methods—
Systematic chart abstraction was performed on consecutive hospitalized patients with ischemic stroke from all 7 acute care hospitals in the District of Columbia from February 1, 2008, to January 31, 2009.

Results—

Of 1044 patients with ischemic stroke, 74% were black, 19% non-Hispanic white, and 5% received intravenous tPA. Blacks were one third less likely than whites to receive intravenous tPA (3% versus 10%,
P
<0.001). However, blacks were also less likely than whites to present within 3 hours of symptom onset (13% versus 21%,
P
=0.004) and also less likely to be tPA-eligible (5% versus 13%,
P
<0.001). Of those who presented within 3 hours, blacks were almost half as likely to be treated with intravenous tPA than whites (27% versus 46%,
P
=0.023). The treatment rate for tPA-eligible patients was similar for blacks and whites (70% versus 76%,
P
=0.62).

Conclusions—
In this predominantly black urban population hospitalized for acute ischemic stroke, blacks were significantly less likely to be treated with intravenous tPA due to contraindications to treatment, delayed presentation, and stroke severity. Effective interventions designed to increase treatment in this population need to focus on culturally relevant education programs designed to address barriers specific to this population.
Early Ischemic Change on CT Versus Diffusion-Weighted Imaging for Patients With Stroke Receiving Intravenous Recombinant Tissue-Type Plasminogen Activator Therapy
Authors: Nezu Tomohisa , Koga Masatoshi , Nakagawara Jyoji , Shiokawa Yoshiaki , Yamagami Hiroshi , Furui Eisuke , Kimura Kazumi , Hasegawa Yasuhiro , Okada Yasushi , Okuda Satoshi , Kario Kazuomi , Naganuma Masaki , Maeda Koichiro , Minematsu Kazuo , Toyoda Kazunori 
Published: July 2011

Background and Purpose—
Alberta Stroke Programme Early CT Score (ASPECTS) is a quantitative topographical score to evaluate early ischemic change in the middle cerebral arterial territory on CT as well as on diffusion-weighted imaging (DWI). The aim of the present study was to elucidate the relationship between CT-ASPECTS and DWI-ASPECTS for patients with hyperacute stroke and their associations with outcomes after recombinant tissue-type plasminogen activator therapy based on a multicenter registry.

Methods—
ASPECTS was assessed on both CT and DWI before intravenous 0.6 mg/kg alteplase in 360 patients with stroke (119 women, 71±11 years old). The outcomes were symptomatic intracerebral hemorrhage within 36 hours and independence at 3 months defined by a modified Rankin Scale score of 0 to 2.

Results—

DWI-ASPECTS was positively correlated with CT-ASPECTS (ρ=0.511,
P
<0.001) and was lower than CT-ASPECTS (median 8 [interquartile range, 6 to 9] versus 9 [8 to 10],
P
<0.001). Higher baseline National Institutes of Health Stroke Scale score (standardized partial regression coefficient [β] 0.061,
P
<0.001) and cardioembolic stroke (β 0.35,
P
<0.001) were related to this discrepancy. The area under the receiver operating characteristic curve for predicting sICH (12 patients) using ASPECTS was 0.673 (95% CI, 0.503 to 0.807) by CT and 0.764 (95% CI, 0.635 to 0.858) by DWI (
P
=0.275). The area for predicting independence at 3 months (192 patients) was 0.621 (0.564 to 0.674) by CT and 0.639 (0.580 to 0.694) by DWI (
P
=0.535).

Conclusions—
For patients with hyperacute stroke, DWI-ASPECTS scored approximately 1 point lower than CT-ASPECTS. Both CT-ASPECTS and DWI-ASPECTS were useful predictors of symptomatic intracerebral hemorrhage and independence at 3 months after recombinant tissue-type plasminogen activator.
Cost-Effectiveness of Tissue-Type Plasminogen Activator in the 3- to 4.5-Hour Time Window for Acute Ischemic Stroke
Authors: Tung Christie E. , Win Sandra S. , Lansberg Maarten G. 
Published: July 2011

Background and Purpose—
The aim of this study was to determine the cost-effectiveness of tissue-type plasminogen activator (tPA) treatment in the 3- to 4.5-hour time window after ischemic stroke.

Methods—
Decision-analytic and Markov state-transition models were created to determine the cost-effectiveness of treatment of ischemic stroke patients with intravenous tPA administered in the 3- to 4.5-hour time window compared with medical therapy without tPA. Health benefits were measured in quality-adjusted life-years (QALYs). The economic outcome measure of the model was the difference in estimated healthcare costs between the 2 treatment alternatives. The incremental cost-effectiveness ratio was calculated by dividing the cost difference by the difference in QALYs. One-way sensitivity and probabilistic analyses were performed to test the robustness of the model.

Results—
The administration of tPA compared with standard medical therapy resulted in a lifetime gain of 0.28 QALYs for an additional cost of $6050, yielding an incremental cost-effectiveness ratio of $21 978 per QALY. One-way sensitivity analyses demonstrated that the incremental cost-effectiveness ratio was most sensitive to the cost of hospitalization for patients who received tPA. Based on probabilistic analysis, there is an 88% probability that tPA is the preferred treatment at a willingness-to-pay threshold of $50 000 per QALY.

Conclusions—
The balance of costs and benefits favors treatment with intravenous tPA in the 3- to 4.5-hour time window. This supports, from a societal perspective, the use of tPA therapy in this treatment time window for acute ischemic stroke.
Self-Expandable Stents in the Treatment of Acute Ischemic Stroke Refractory to Current Thrombectomy Devices
Authors: Linfante Italo , Samaniego Edgar A. , Geisbüsch Philipp , Dabus Guilherme 
Published: July 2011

Background and Purpose—
Vessel recanalization is a strong predictor of good outcome in acute ischemic strokes (AIS) secondary to large vessel occlusions. We report our single-center experience with self-expandable stents in the treatment of AIS.

Methods—
The stroke database of Baptist Cardiac and Vascular Institute in Miami was retrospectively reviewed from August of 2008 to September of 2010. All cases of AIS in which a self-expandable stents was deployed as acute endovascular intervention were included in the analysis. Criteria for intervention were the onset of neurological symptoms because of AIS, a National Institute of Health Stroke Scale score ≥4 at presentation, stroke attributable to a large vessel occlusion, and failure of arterial thrombolysis or mechanical thrombectomy or both. Good outcome was defined as a modified Rankin Scale score ≤2 at 1 month from hospital discharge.

Results—
Nineteen patients with AIS who underwent stenting were identified. Median National Institute of Health Stroke Scale score on admission was 19. Six Enterprise and 13 Wingspan stents were deployed. Recanalization was achieved in 95% occlusions (63% thrombolysis in myocardial infarction grade 3 and 32% thrombolysis in myocardial infarction grade 2). Good clinical outcome was achieved in 42%. No intraprocedural complications occurred and all stents were successfully deployed. Symptomatic intracerebral hemorrhage occurred in 3 (16%) patients, 2 of whom died.

Conclusions—
Use of self-expandable stents in AIS appears to be safe and may be considered when currently available thrombectomy devices and/or intraarterial thrombolysis fail.
Optimal End Points for Acute Stroke Therapy Trials
Authors: Saver Jeffrey L. 
Published: July 2011

Background and Purpose—
Over the past decade, analysis of completed actual trials, model population studies, and theoretical work have improved approaches to selecting and analyzing end points in acute stroke treatment trials.

Methods—
Narrative review.

Results—
Because stroke affects persons in their biological, functional, social, and experiential dimensions, measures of impairment, disability, handicap, and quality of life are all desirable in pivotal trials, with disability being most important. Scales that are valid, reliable, responsive, and easy to administer are preferred; consequently, the modified Rankin Scale has become the most widely used single clinical efficacy measure. Because stroke cripples and kills, most outcome scales array patient outcome in ordered ranks, spread over the entire range from normal to disabled to dead. Generally, shift analysis, analyzing all health state transitions concurrently, is the most efficient analytic technique to detect treatment effects, with sliding dichotomy less efficient and fixed dichotomy least efficient, unless treatment effects strongly cluster at 1 or a few health state transitions that can be prespecified. Test statistics must also take into account interpretability, ie, how well they can be converted into metrics capturing all outcomes the intervention might alter in proportion to the degree they are valued by the patient; full ordinal analysis is most informative, sliding dichotomy is intermediately informative, and fixed dichotomy is least informative regarding this global outcome.

Conclusions—
Stroke trial power and interpretation can be substantially enhanced by adherence to the principles delineated in this review. Full ordinal and sliding dichotomy analysis will most often be advantageous compared with fixed dichotomous approaches.
1997/98 El Niño–Induced Changes in Rainfall Vertical Structure in the East Pacific
Authors: Li Rui , Min Qilong , Fu Yunfei 
Published: July 2011

Abstract
The 1997/98 El Niño–induced changes in rainfall vertical structure in the east Pacific (EP) are investigated by using collocated Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) and associated daily SST and 6-hourly reanalysis data during January, February, March, and April of 1998, 1999, and 2000. This study shows that there are five key parameters, that is, surface rain rate, precipitation-top height (or temperature), and precipitation growth rates at upper, middle, and low layers to define a rainfall profile, and those five key parameters are strongly influenced by both SST and large-scale dynamics. Under the influence of 1997/98 El Niño, the precipitation-top heights in the EP were systematically higher by about 1 km than those under non–El Niño conditions, while the freezing level was about 0.5 km higher. Under the constraints of rain type, surface rain rate, and the precipitation top, the shape of rainfall profile still showed significant differences: the rain growth was relatively faster in the mid-layer (−5° to +2°C isotherm) but slower in the lower layer (below +2°C isotherm) under the influence of El Niño. It is also evident that the dependence of precipitation top height on SST was stronger under large-scale decent (non–El Niño) circulations but much weaker under large-scale ascent (El Niño) circulations. The combined effect of larger vertical extent and greater growth rate in the middle layer further shifted latent heating upward as compared with the impact of horizontal changes in the rain type fractions (convective versus stratiform). Such additional latent heating shift would certainly further elevate circulation centers and strengthen the upper-layer circulation.
WATCH: Current Knowledge of the Terrestrial Global Water Cycle
Authors: Harding Richard , Best Martin , Blyth Eleanor , Hagemann Stefan , Kabat Pavel , Tallaksen Lena M. , Warnaars Tanya , Wiberg David , Weedon Graham P. , Lanen Henny van , Ludwig Fulco , Haddeland Ingjerd 
Published: July 2011

AbstractWater-related impacts are among the most important consequences of increasing greenhouse gas concentrations. Changes in the global water cycle will also impact the carbon and nutrient cycles and vegetation patterns. There is already some evidence of increasing severity of floods and droughts and increasing water scarcity linked to increasing greenhouse gases. So far, however, the most important impacts on water resources are the direct interventions by humans, such as dams, water extractions, and river channel modifications. The Water and Global Change (WATCH) project is a major international initiative to bring together climate and water scientists to better understand the current and future water cycle. This paper summarizes the underlying motivation for the WATCH project and the major results from a series of papers published or soon to be published in the Journal of Hydrometeorology WATCH special collection. At its core is the Water Model Intercomparison Project (WaterMIP), which brings together a wide range of global hydrological and land surface models run with consistent driving data. It is clear that we still have considerable uncertainties in the future climate drivers and in how the river systems will respond to these changes. There is a grand challenge to the hydrological and climate communities to both reduce these uncertainties and communicate them to a wider society.
The Effect of Koshu Seamount on the Formation of the Kuroshio Large Meander South of Japan
Authors: Endoh Takahiro , Tsujino Hiroyuki , Hibiya Toshiyuki 
Published: July 2011

Abstract
Using an inflow–outflow numerical model, the authors demonstrate that the existence of Koshu Seamount, located about 200 km to the south of Cape Shiono-misaki, is essential in creating the large meander (LM) of the Kuroshio. When Koshu Seamount is completely smoothed out, the meander trough propagates away without being amplified to form the LM. In contrast, nearly the same LM as in the case with full topography is formed when the foot of Koshu Seamount remains without being smoothed out and also when the foot of Koshu Seamount is filled in so that the upper part of Koshu Seamount remains. A linear stability analysis applied to the model output shows that the Kuroshio becomes baroclinically most unstable when the water depth decreases offshoreward. The authors therefore conclude that the enhancement of baroclinic instability over the northern slope of Koshu Seamount is a prerequisite to the formation of the LM.
Radar Backscattering from Snowflakes: Comparison of Fractal, Aggregate, and Soft Spheroid Models
Authors: Tyynelä Jani , Leinonen Jussi , Moisseev Dmitri , Nousiainen Timo 
Published: July 2011

Abstract
The sensitivity of radar backscattering cross sections on different snowflake shapes is studied at C, Ku, Ka, and W bands. Snowflakes are simulated using two complex shape models, namely, fractal and aggregate, and a soft spheroid model. The models are tuned to emulate physical properties of real snowflakes, that is, the mass–size relation and aspect ratio. It is found that for particle sizes up to 5 mm and for frequencies from 5 to 35 GHz, there is a good agreement in the backscattering cross section for all models. For larger snowflakes at the Ka band, it is found that the spheroid model underestimates the backscattering cross sections by a factor of 10, and at W band by a factor of 50–100. Furthermore, there is a noticeable difference between spheroid and complex shape models in the linear depolarization ratios for all frequencies and particle sizes.
Experimental Tropical Cyclone Prediction Using the GFDL 25-km-Resolution Global Atmospheric Model
Authors: Gall Jeffrey S. , Ginis Isaac , Lin Shian-Jiann , Marchok Timothy P. , Chen Jan-Huey 
Published: July 2011

Abstract
This paper describes a forecasting configuration of the Geophysical Fluid Dynamics Laboratory (GFDL) High-resolution Atmospheric Model (HiRAM). HiRAM represents an early attempt in unifying, within a global modeling framework, the capabilities of GFDL’s low-resolution climate models for Intergovernmental Panel on Climate Change (IPCC) type climate change assessments and high-resolution limited-area models for hurricane predictions. In this study, the potential of HiRAM as a forecasting tool is investigated by applying the model to the near-term and intraseasonal hindcasting of tropical cyclones (TCs) in the Atlantic basin from 2006 to 2009. Results demonstrate that HiRAM provides skillful near-term forecasts of TC track and intensity relative to their respective benchmarks from t = 48 h through t = 144 h. At the intraseasonal time scale, a simple HiRAM ensemble provides skillful forecasts of 21-day Atlantic basin TC activity at a 2-day lead time. It should be noted that the methodology used to produce these hindcasts is applicable in a real-time forecasting scenario. While the initial experimental results appear promising, the HiRAM forecasting system requires various improvements in order to be useful in an operational setting. These modifications are currently under development and include a data assimilation system for forecast initialization, increased horizontal resolution to better resolve the vortex structure, 3D ocean model coupling, and wave model coupling. An overview of these ongoing developments is provided, and the specifics of each will be described in subsequent papers.