bluuebunny/crossref_metadata_2025 huggingface dataset:
Intravenous Tissue Plasminogen Activator Thrombolysis in Patients without Major Arterial Occlusion Seems to Be Safe and Effective
Authors: Kimura Kazumi , Iguchi Yasuyuki , Shibazaki Kensaku , Sakamoto Yuki , Watanabe Masao
Published: October 2010

Background: It is not clear whether tissue plasminogen activator (t-PA) thrombolysis in patients without major arterial occlusion is effective or safe. Methods: Consecutive anterior circulation stroke patients treated with t-PA within 3 h of onset were studied. The patients were divided into three groups according to magnetic resonance angiography findings before t-PA infusion: ICA group, ICA occlusion; MCA group, M1 and M2 occlusion, and no occlusion group. Clinical characteristics, the presence of hemorrhagic transformation on T2* at 24 h after t-PA thrombolysis, and outcome at 3 months were compared among the three groups. Results: 112 patients were enrolled. The no occlusion group had 21 (18.8%) patients, the ICA group had 29 (25.9%), and the MCA group had 62 (55.4%). The frequency of hemorrhagic transformation was only 4.8% in the no occlusion group (31.0% for the ICA group, and 48.4% for the MCA group, p = 0.0012). At 3 months after t-PA therapy, 61.5% of the no occlusion group had a favorable outcome (modified Rankin score 0–1), which was the highest among the three groups (15.0% for the ICA group, and 41.5% for the MCA group, p = 0.0203). Conclusion: Intravenous t-PA therapy in acute stroke patients without major artery occlusion seems to be safe and effective.
The Best Way to Detect Elevated Albuminuria
Authors: Deeb Abbas , Hadj-Aissa Aoumeur , Ducher Michel , Chapuis-Cellier Colette , Fauvel Jean-Pierre
Published: October 2010

Background: It has been reported that first morning specimens are more reliable than random spot specimens to assess 24-hour urinary albumin excretion rate (UAER), especially if albuminuria is expressed as albuminuria to creatininuria ratio. We aimed to investigate the influence of (a) posture and activity and (b) the units to best estimate 24-hour albuminuria. Methods: In this retrospective study, 24-hour UAER was compared to 60 min ‘supine’ and 90 min ‘activity’ albuminuria in 124 patients tested for resistant hypertension. The ability to adjust urinary albumin concentration (UAC) to creatininuria (ACR) or to collection duration (tAER) values in order to increase the reliability of albuminuria values was also analyzed. Results: Compared to 24-hour UAER, UAC (mg/l), tAER (µg/min) and ACR (mg/mmol) during the supine period had a similar concordance rate in normo-, micro- and macroalbuminuric patients. The UAC in the supine period was well related to 24-hour UAER. However, UAC almost doubled during activity. Adjustment to creatininuria improved the correlation between albuminuria during both periods and 24-hour UAER, but mainly during the activity period. Conclusions: Our results confirm that UAC is dependent on physical activity. Correction of UAC by creatininuria (ACR) provides a satisfactory estimation of 24-hour UAER. Thus, for practical reasons, it is advisable to use ACR, where no differences appear to exist, whether a supine urine sample or an activity urine sample is obtained.
Single Estimated Glomerular Filtration Rate and Albuminuria Measurement Substantially Overestimates Prevalence of Chronic Kidney Disease
Authors: Bottomley M.J. , Kalachik A. , Mevada C. , Brook M.O. , James T. , Harden P.N.
Published: October 2010

Background/Aims: Guidelines require repeatedly diminished estimated glomerular filtration rate (eGFR) and/or albuminuria to diagnose chronic kidney disease (CKD), and advise screening only in select populations. Many estimates of CKD prevalence have used single measurements. This longitudinal study assessed eGFR and albuminuria reproducibility, and impact on estimate of CKD prevalence, in factory workers. Methods: A total of 512 white workers in a Belarusian industrial factory were initially tested, identifying 206 with abnormal (eGFR <59 ml/min/1.73 m2 or albuminuria) or near-abnormal (eGFR up to 1 SD above abnormal) renal function. At 3 months, 142 of the abnormal/near-abnormal cohort were re-tested. Results: Analysis of repeat samples revealed no significant change in eGFR in this population, however 21% individually changed CKD stage. Initial proteinuria was reproducible in only 48% at 3 months. This had a major impact on estimated CKD prevalence: a point prevalence of 8.2% halved with repeat testing. The predictive value of initially abnormal eGFR or albuminuria for repeat abnormality at 3 months was 0.5. Conclusion: Non-targeted screening for CKD is inaccurate and can overestimate prevalence. This study emphasises the importance of confirming abnormal eGFR and proteinuria on at least one further sample 3 months apart before categorising the individual as having CKD. This has wide implications for screening in European general populations.
NF-E2–Related Factor 2 Promotes Atherosclerosis by Effects on Plasma Lipoproteins and Cholesterol Transport That Overshadow Antioxidant Protection
Authors: Barajas Berenice , Che Nam , Yin Fen , Rowshanrad Amir , Orozco Luz D. , Gong Ke Wei , Wang Xuping , Castellani Lawrence W. , Reue Karen , Lusis Aldons J. , Araujo Jesus A.
Published: October 2010

Objective—

To test the hypothesis that NF-E2–related factor 2 (Nrf2) expression plays an antiatherogenic role by its vascular antioxidant and anti-inflammatory properties.

Methods and Results—

Nrf2 is an important transcription factor that regulates the expression of phase 2 detoxifying enzymes and antioxidant genes. Its expression in vascular cells appears to be an important factor in the protection against vascular oxidative stress and inflammation. We developed Nrf2 heterozygous (HET) and homozygous knockout (KO) mice on an apolipoprotein (apo) E–null background by sequential breeding, resulting in Nrf2
−/−
, apoE
−/−
(KO), Nrf2
−/+
, apoE
−/−
(HET) and Nrf2
+/+
, and apoE
−/−
wild-type littermates. KO mice exhibited decreased levels of antioxidant genes with evidence of increased reactive oxygen species generation compared with wild-type controls. Surprisingly, KO males exhibited 47% and 53% reductions in the degree of aortic atherosclerosis compared with HET or wild-type littermates, respectively. Decreased atherosclerosis in KO mice correlated with lower plasma total cholesterol in a sex-dependent manner. KO mice also had a decreased hepatic cholesterol content and a lower expression of lipogenic genes, suggesting that hepatic lipogenesis could be reduced. In addition, KO mice exhibited atherosclerotic plaques characterized by a lesser macrophage component and decreased foam cell formation in an in vitro lipid-loading assay. This was associated with a lower rate of cholesterol influx, mediated in part by decreased expression of the scavenger receptor CD36.

Conclusion—

Nrf2 expression unexpectedly promotes atherosclerotic lesion formation in a sex-dependent manner, most likely by a combination of systemic metabolic and local vascular effects.
Matrix Metalloproteinase Activation Predicts Amelioration of Remodeling After Dietary Modification in Injured Arteries
Authors: Tavakoli Sina , Razavian Mahmoud , Zhang Jiasheng , Nie Lei , Marfatia Ravi , Dobrucki Lawrence W. , Sinusas Albert J. , Robinson Simon , Edwards D. Scott , Sadeghi Mehran M.
Published: October 2010

Objective—

To establish and validate early noninvasive imaging of matrix metalloproteinase (MMP) activation for monitoring the progression of vascular remodeling and response to dietary modification.

Methods and Results—

Apolipoprotein E
−/−
mice that were fed a high-fat diet underwent left common carotid artery wire injury. One week after surgery, a group of animals were withdrawn from the high-fat diet. The other group of animals continued that diet throughout the study. Micro single-photon emission computed tomographic (microSPECT)/CT imaging with RP805 (a
99m
Tc-labeled tracer targeting activated MMPs) was repeatedly performed at 2 and 4 weeks after surgery. Histological analysis at 4 weeks showed significant left carotid neointima formation, monocyte/macrophage infiltration, and upregulation of several MMPs, which were ameliorated by withdrawal from the high-fat diet. In vivo microSPECT/CT images visualized significant RP805 uptake, reflecting MMP activation, in the injured carotid arteries. MMP activation was reduced as early as 1 week after withdrawal from the high-fat diet and significantly correlated with neointimal area at 4 weeks after surgery.

Conclusion—

MMP activation predicts the progression of vascular remodeling and can track the effect of dietary modification after vascular injury.
Increased Serum N-Terminal Pro–B-Type Natriuretic Peptide Levels in Patients With Medial Arterial Calcification and Poorly Compressible Leg Arteries
Authors: Jouni Hayan , Rodeheffer Richard J. , Kullo Iftikhar J.
Published: October 2010

Objective—

To determine whether serum levels of N-terminal (NT) pro–B-type natriuretic peptide (pro-BNP) are higher in patients with poorly compressible arteries (PCA) than in patients with peripheral artery disease (PAD) and control subjects without PCA or PAD.

Methods and Results—

Medial arterial calcification in the lower extremities results in PCA and may be associated with increased arterial stiffness and hemodynamic/myocardial stress. PCA was defined as having an ankle-brachial index >1.4 or an ankle blood pressure >255 mm Hg, whereas PAD was defined as having an ankle-brachial index ≤0.9. Study participants with PCA (n=100; aged 71±10 years; 70% men) and age- and sex-matched patients with PAD (n=300) were recruited from the noninvasive vascular laboratory. Age- and sex-matched controls (n=300) were identified from a community-based cohort and had no history of PAD. NT pro-BNP levels were approximately 2.5-fold higher in patients with PCA than in patients with PAD and approximately 4-fold higher than in age- and sex-matched controls. In multivariable regression analyses that adjusted for age, sex, smoking, hypertension, history of coronary heart disease/stroke, systolic blood pressure, and serum creatinine, NT pro-BNP levels remained significantly higher in patients with PCA than in patients with PAD and controls (
P
<0.001).

Conclusion—

Patients with medial arterial calcification and PCA have higher serum levels of NT pro-BNP than patients with PAD and controls, which is suggestive of an adverse hemodynamic milieu and increased risk for adverse cardiovascular outcomes.
A Major Role for hERG in Determining Frequency of Reentry in Neonatal Rat Ventricular Myocyte Monolayer
Authors: Hou Luqia , Deo Makarand , Furspan Philip , Pandit Sandeep V. , Mironov Sergey , Auerbach David S. , Gong Qiuming , Zhou Zhengfeng , Berenfeld Omer , Jalife José
Published: October 2010

Rationale:

The rapid delayed rectifier potassium current,
I
Kr
, which flows through the human ether-a-go-go-related (hERG) channel, is a major determinant of the shape and duration of the human cardiac action potential (APD). However, it is unknown whether the time dependency of
I
Kr
enables it to control APD, conduction velocity (CV), and wavelength (WL) at the exceedingly high activation frequencies that are relevant to cardiac reentry and fibrillation.

Objective:

To test the hypothesis that upregulation of hERG increases functional reentry frequency and contributes to its stability.

Methods and Results:

Using optical mapping, we investigated the effects of
I
Kr
upregulation on reentry frequency, APD, CV, and WL in neonatal rat ventricular myocyte (NRVM) monolayers infected with GFP (control), hERG (
I
Kr
), or dominant negative mutant hERG G628S. Reentry frequency was higher in the
I
Kr
-infected monolayers (21.12±0.8 Hz; n=43 versus 9.21±0.58 Hz; n=16;
P
<0.001) but slightly reduced in G628S-infected monolayers. APD
80
in the
I
Kr
-infected monolayers was shorter (>50%) than control during pacing at 1 to 5 Hz. CV was similar in both groups at low frequency pacing. In contrast, during high-frequency reentry, the CV measured at varying distances from the center of rotation was significantly faster in
I
Kr
-infected monolayers than controls. Simulations using a modified NRVM model predicted that rotor acceleration was attributable, in part, to a transient hyperpolarization immediately following the AP. The transient hyperpolarization was confirmed experimentally.

Conclusions:

hERG overexpression dramatically accelerates reentry frequency in NRVM monolayers. Both APD and WL shortening, together with transient hyperpolarization, underlies the increased rotor frequency and stability.
AXIS
Authors: Schäbitz Wolf R. , Laage Rico , Vogt Gerhard , Koch Winfried , Kollmar Rainer , Schwab Stefan , Schneider Dietmar , Hamann Gerhard F. , Rosenkranz Michael , Veltkamp Roland , Fiebach Jochen B. , Hacke Werner , Grotta James C. , Fisher Marc , Schneider Armin
Published: October 2010

Background and Purpose—

Granulocyte colony-stimulating factor (G-CSF) is a promising stroke drug candidate. The present phase IIa study assessed safety and tolerability over a broad dose range of G-CSF doses in acute ischemic stroke patients and explored outcome data.

Methods—

Four intravenous dose regimens (total cumulative doses of 30–180 μg/kg over the course of 3 days) of G-CSF were tested in 44 patients in a national, multicenter, randomized, placebo-controlled dose escalation study (NCT00132470; www.clinicaltrial.gov). Main inclusion criteria were a 12-hour time window after stroke onset, infarct localization to the middle cerebral artery territory, a baseline National Institutes of Health Stroke Scale range of 4 to 22, and presence of diffusion-weighted imaging/perfusion-weighted imaging mismatch.

Results—

Concerning the primary safety end points, we observed no increase of thromboembolic events in the active treatment groups, and no increase in related serious adverse events. G-CSF led to expected increases in neutrophils and monocytes that resolved rapidly after end of treatment. We observed a clinically insignificant drug-related decrease of platelets. As expected from the low number of patients, we did not observe significant differences in clinical outcome in treatment vs. placebo. In exploratory analyses, we observed an interesting dose-dependent beneficial effect of treatment in patients with DWI lesions >14–17 cm
3
.

Conclusions—

We conclude that G-CSF was well-tolerated even at high dosages in patients with acute ischemic stroke, and that a substantial increase in leukocytes appears not problematic in stroke patients. In addition, exploratory analyses suggest treatment effects in patients with larger baseline diffusion-weighted imaging lesions. The obtained data provide the basis for a second trial aimed to demonstrate safety and efficacy of G-CSF on clinical end points.
Arsenic in Drinking Water and Stroke Hospitalizations in Michigan
Authors: Lisabeth Lynda D. , Ahn Hyeong Jun , Chen John J. , Sealy-Jefferson Shawnita , Burke James F. , Meliker Jaymie R.
Published: October 2010

Background and Purpose—

Mechanistic and human studies suggest a role for arsenic in ischemic stroke; however, risks from chronic, low-level exposures are uncertain and US studies are lacking. The objective was to investigate the association between low-level arsenic exposure in drinking water and ischemic stroke hospital admissions in Michigan.

Methods—

Ischemic stroke hospital admissions among those aged ≥45 years were identified (1994 to 2006). Population-weighted average arsenic concentrations were estimated for each Michigan county (n=83) and for zip codes in Genesee County (n=27) where there is greater variation in arsenic concentrations. US Census data provided age- and sex-specific population counts and other county- and zip code-level variables (race, income), which were adjusted for in multilevel negative binomial regression models of arsenic and stroke admissions. Hospital admissions for duodenal ulcer and hernia, not hypothesized to be associated with arsenic, were also evaluated.

Results—

Adjusted county-level analyses suggested a relationship between arsenic and ischemic stroke hospital admissions, although similar associations were observed for duodenal ulcer and hernia. In zip code-level analysis, arsenic was associated with an increased risk of stroke admission (relative risk, 1.03; 95% CI, 1.01 to 1.05 per μg/L increase in arsenic) after adjustment for confounders, and null or negative associations were found between arsenic and nonvascular outcomes.

Conclusions—

Findings from this study suggest that exposure to even low levels of arsenic in drinking water may be associated with a higher risk of incident stroke. Given the ecological nature of the analysis, further epidemiological study with individual-level data on arsenic exposure and incident stroke is warranted.
Stratified, Urgent Care for Transient Ischemic Attack Results in Low Stroke Rates
Authors: Wasserman Jason , Perry Jeff , Dowlatshahi Dar , Stotts Grant , Stiell Ian , Sutherland Jane , Symington Cheryl , Sharma Mukul
Published: October 2010

Background and Purpose—

Transient ischemic attack (TIA) is a marker for early risk of stroke. No previous studies have assessed the use of urgent stroke prevention clinics for emergency department (ED) patients with TIA. We hypothesized that an ABCD2-based ED triaging tool for TIA with outpatient management would be associated with lower 90-day stroke rate than that predicted by ABCD2.

Methods—

A cohort of prospectively identified patients presenting with symptoms suggestive of TIA seen in 2 tertiary-care EDs. These patients were divided into 3 strata based on their ACBD2 score, and triage targets were set for each stratum. All patients received the same standard of care in the Stroke Clinic regardless of their risk score. Primary outcome was stroke by 90 days of index TIA. Secondary outcomes were subsequent TIA, myocardial infarction, or death.

Results—

One-thousand ninety-three patients met the inclusion criteria; 982 patients completed 90-day follow-up and comprised the final cohort. After stratification, 32%, 49%, and 19% of patients were categorized as low-, moderate-, or high-risk, respectively. The overall 90-day risk of stroke in all patients was 3.2%, compared with the ABCD2-predicted risk of 9.2%. Only 1.6% of patients with TIA/minor stroke were admitted from the ED. The risk of subsequent TIA, myocardial infarction, or death by 90 days was 5.5%, 0.1%, and 1.7%, respectively.

Conclusion—

Outpatient care in a rapid-access stroke prevention clinic using the ABCD2 score for triage resulted in a low 90-day stroke rate for patients in the ED with TIA. Benefit occurred without requiring admission for most patients.
Early Mobilization After Stroke
Authors: Craig Louise E. , Bernhardt Julie , Langhorne Peter , Wu Olivia
Published: October 2010

Background and Purpose—

Very early mobilization (VEM) is a distinctive characteristic of care in some stroke units; however, evidence of the effectiveness of this approach is limited. To date, only 2 phase II trials have compared VEM with standard care: A Very Early Rehabilitation Trial (AVERT) in Australia and the recently completed Very Early Rehabilitation or Intensive Telemetry after Stroke trial in the United Kingdom. The Very Early Rehabilitation or Intensive Telemetry after Stroke protocol was designed to complement that of AVERT in a number of key areas. The aim of this analysis was to investigate the impact of VEM on independence by pooling data from these 2 comparable trials.

Methods—

Individual data from the 2 trials were pooled. Overall, patients were between 27 and 97 years old, had first or recurring stroke, and were treated within 36 hours after stroke onset. The primary outcome was independence, defined as modified Rankin scale score of 0 to 2 at 3 months. The secondary outcomes included complications of immobility and activities of daily living. Logistic regression was used to assess the effect of VEM on outcome, adjusting for known confounders including age, baseline stroke severity, and premorbid modified Rankin scale score.

Findings—

All patients in AVERT and Very Early Rehabilitation or Intensive Telemetry after Stroke were included, resulting in 54 patients in the VEM group and 49 patients in the standard care group. The baseline characteristics of VEM patients were largely comparable with standard care patients. Time to first mobilization from symptom onset was significantly shorter among VEM patients (median, 21 hours; interquartile range, 15.8–27.8 hours) compared with standard care patients (median, 31 hours; interquartile range, 23.0–41.2 hours). VEM patients had significantly greater odds of independence compared with standard care patients (adjusted odds ratio, 3.11; 95% confidence interval, 1.03–9.33).

Conclusions—

Planned collaborations between stroke researchers to conduct trials with common protocols and outcome measures can help advance rehabilitation science. VEM was associated with improved independence at 3 months compared with standard care. However, both trials are limited by small sample sizes. Larger trials (such as AVERT phase III) are still needed in this field.
Burden Among Stroke Caregivers
Authors: Das Sujata , Hazra Avijit , Ray Biman Kanti , Ghosal Malay , Banerjee Tapas Kumar , Roy Trishit , Chaudhuri Arijit , Raut Deepak K. , Das Shyamal Kumar
Published: October 2010

Background and Purpose—

Stroke causes significant caregiver (CG) stress, which is under-reported in India. This study assesses the financial, physical, psychological, and family burden on CG of stroke patients in an urban community.

Methods—

Cross-sectional survey of stroke patients and CG were selected from a community-based registry using validated scales through face-to-face interviews.

Results—

Data were available from 199 stroke survivors and a similar number of CG. Increased workload, related anxiety and depression, and sleep disturbance were reported by 70%, 76%, and 43% of CG, respectively, whereas >80% reported financial worry, which was greater among slum dwellers and less educated families. CG of patients with dementia and depression experienced greater stress. Female CG received more appreciation and family bonding was well-maintained.

Conclusions—

Financial stress was prominent and common among the socioeconomically weaker section. Psychological stress is similar to that of other studies. Women CG received greater appreciation. Family bonding was well-preserved in contrast to that of a western report.
Leonurine Protects Middle Cerebral Artery Occluded Rats Through Antioxidant Effect and Regulation of Mitochondrial Function
Authors: Loh Kok Poh , Qi Jia , Tan Benny Kwong Huat , Liu Xin Hua , Wei Bang Guo , Zhu Yi Zhun
Published: October 2010

Background and Purpose—

Oxidative stress is known to be involved in ischemic stroke. Intense interest is drawn to the therapeutic potential of Chinese herbs on ischemic stroke because many of them contain antioxidant properties. Leonurine, 1 of the active compounds from purified Herba Leonuri, was studied to evaluate its possible therapeutic effects on ischemic stroke.

Method—

Middle cerebral artery occlusion was selected as our model of study. The animals were pretreated with Leonurine orally for 7 days and the surgery was done. One day after surgery, 2,3,5-triphenyltetrazolium chloride staining and neurological deficit score were carried out to evaluate the functional outcome of animals, whereas levels of superoxide dismutase, glutathione peroxidase, and malondialdehyde were analyzed for oxidative stress analysis. For mitochondrial studies, 3 hours after surgery, mitochondria were isolated for analysis of reactive oxygen species production, adenosine triphosphate biosynthesis, oxygen consumption, and respiratory control ratio value.

Result—

In in vivo experiments, Leonurine pretreatment reduced infarct volume, improved neurological deficit in stroke groups, increased activities of antioxidant enzymes superoxide dismutase and glutathione peroxidase, and decreased levels from the lipid peroxidation marker malondialdehyde. In terms of mitochondrial modulation, Leonurine inhibited mitochondrial reactive oxygen species production and adenosine triphosphate biosynthesis. Animal studies also demonstrated that the mitochondrial function and redox state were restored by Leonurine treatment.

Conclusions—

Leonurine has neuroprotective effects and carries a therapeutic potential of stroke prevention.
MRI Profile of the Perihematomal Region in Acute Intracerebral Hemorrhage
Authors: Olivot Jean-Marc , Mlynash Michael , Kleinman Jonathan T. , Straka Matus , Venkatasubramanian Chitra , Bammer Roland , Moseley Michael E. , Albers Gregory W. , Wijman Christine A.C.
Published: October 2010

Background and Purpose—

The pathophysiology of the presumed perihematomal edema immediately surrounding an acute intracerebral hemorrhage is poorly understood, and its composition may influence clinical outcome.

Method—

Twenty-three patients from the Diagnostic Accuracy of MRI in Spontaneous intracerebral Hemorrhage (DASH) study were prospectively enrolled and studied with MRI. Perfusion-weighted imaging, diffusion-weighted imaging, and fluid-attenuated inversion recovery sequences were coregistered. TMax (the time when the residue function reaches its maximum) and apparent diffusion coefficient values in the presumed perihematomal edema regions of interest were compared with contralateral mirror and remote ipsilateral hemispheric regions of interest.

Results—

Compared with mirror and ipsilateral hemispheric regions of interest, TMax (the time when the residue function reaches its maximum) and apparent diffusion coefficient were consistently increased in the presumed perihematomal edema. Two thirds of the patients also exhibited patchy regions of restricted diffusion in the presumed perihematomal edema.

Conclusion—

The MRI profile of the presumed perihematomal edema in acute intracerebral hemorrhage exhibits delayed perfusion and increased diffusivity mixed with areas of reduced diffusion.
Stent-Assisted Mechanical Recanalization for Treatment of Acute Intracerebral Artery Occlusions
Authors: Roth C. , Papanagiotou P. , Behnke S. , Walter S. , Haass A. , Becker C. , Fassbender K. , Politi M. , Körner H. , Romann M. -S. , Reith W.
Published: October 2010

Background and Purpose—

The purpose of this study was to demonstrate a new approach to the use of a self-expanding stent in the treatment of acute ischemic stroke.

Methods—

Twenty-two consecutive patients with acute intracerebral artery occlusions were treated with a self-expandable intracranial stent, which was withdrawn in its unfolded state. For this technique, we used the Solitaire AB/FR, which is the only intracranial stent that is fully recoverable. Eight patients had an occlusion of the basilar artery, 12 had a middle cerebral artery occlusion, and 2 had terminal carotid artery occlusions; 6 of these had to be treated first for an acute occlusion originating in the internal carotid artery. Recanalization results were assessed by follow-up angiography immediately after the procedure. Neurologic status was evaluated before and after treatment (90-day follow-up) according to the National Institutes of Health Stroke Scale and modified Rankin scale.

Results—

Successful revascularization was achieved in 20 of 22 (90.9%) patients (thrombolysis in cerebral infarction [TICI] 2a/b and 3), a TICI 3 state was accomplished in 12 patients, and partial recanalization or slow distal branch filling with filling of more than two-thirds of the vessel territory was achieved in 8 patients (TICI 2b). There was immediate flow restoration in 21 of 22 (95.4%) cases after deployment of the device. The stent was removed in its unfolded state in all patients. The mean time from stroke symptom onset to recanalization was 277 minutes, with a standard deviation of 118 minutes. Mean National Institutes of Health Stroke Scale score on admission was 19.4, with a standard deviation of 5.7. Almost two-thirds of the patients (63.6%) improved by >10 points on the National Institutes of Health Stroke Scale at discharge, and 50% showed a modified Rankin scale score of ≤2 at 90 days (59% with a modified Rankin scale ≤3). Mortality was 18.1%. In 1 case, an asymptomatic intracranial hemorrhage was detected on control computed tomography, and 2 patients had a symptomatic intracranial hemorrhage.

Conclusion—

Withdrawal of an unfolded, fully recoverable, intracranial stent yielded very promising angiographic and clinical results. It combines the advantages of prompt flow restoration and mechanical thrombectomy.
Autoantibodies Against Oxidized Low-Density Lipoprotein in Cerebral Small Vessel Disease
Authors: Rouhl Rob P.W. , van Oostenbrugge Robert J. , Theunissen Ruud O.M.F.I.H. , Knottnerus Iris L.H. , Staals Julie , Henskens Léon H.G. , Kroon Abraham A. , de Leeuw Peter W. , Lodder Jan , Tervaert Jan-Willem Cohen , Damoiseaux Jan G.M.C.
Published: October 2010

Background and Purpose—

Oxidized low-density lipoprotein (oxLDL) induces endothelial dysfunction and antibody formation. Because endothelial dysfunction is involved in cerebral small vessel disease (CSVD) (dilated Virchow Robin spaces, lacunar infarcts, and white matter lesions), oxLDL antibodies could play a role in CSVD pathogenesis. Therefore, we studied oxLDL antibodies in patients with high prevalence of CSVD: lacunar stroke patients and essential hypertensive patients.

Methods—

A total of 158 lacunar stroke patients, 158 hypertensive patients, and 43 healthy controls were included. We determined levels of IgG and IgM against hypochlorite (HOCl) and malondialdehyde (MDA) oxLDL using ELISA (values in optical density).

Results—

Patients with CSVD had higher levels of IgG-HOCl-oxLDL (0.77 versus 0.70;
P
<0.01), as well as lower levels of IgM-MDA-oxLDL (0.55 versus 0.65;
P
<0.05) than patients without such lesions. Higher IgG-HOCl-oxLDL levels were only independently associated with higher numbers of Virchow Robin spaces at the level of the basal ganglia (β=0.218;
P
<0.001).

Conclusions—

An autoinflammatory process with lower levels of IgM antibodies and higher levels of IgG antibodies against oxLDL may be involved in CSVD.
Anamnestic Recall of Stroke-Related Deficits
Authors: Zierath Dannielle , Hadwin Jessica , Savos Anna , Carter Kelly T. , Kunze Allison , Becker Kyra J.
Published: October 2010

Background and Purpose—

Anamnestic recall of stroke-related deficits is a common clinical observation, especially during periods of systemic infection. The pathophysiology of this transient re-emergence of neurological dysfunction is unknown.

Methods—

Male Lewis rats underwent 3 hours middle cerebral artery occlusion and were treated with lipopolysaccharide or saline at the time of reperfusion. The delayed-type hypersensitivity (DTH) response to myelin basic protein was examined 28 days after middle cerebral artery occlusion. Changes in behavioral outcomes were assessed after DTH testing and repeat administration of lipopolysaccharide or saline at 34 days. At the time of euthanasia (36 days), the immunologic response of splenocytes to myelin basic protein, neuron-specific enolase, and proteolipid protein was determined by enzyme-linked immunospot assay and the number of lymphocytes in the brain determined by immunocytochemistry.

Results—

Animals treated with lipopolysaccharide at middle cerebral artery occlusion had a greater DTH response to myelin basic protein than animals treated with saline. Among those animals that had fully recovered on a given behavioral test before DTH testing, those treated with lipopolysaccharide at middle cerebral artery occlusion displayed more neurological deterioration after DTH testing and had more CD8
+
lymphocytes within the ischemic core of the brain. Furthermore, the Th1 immune response to brain antigens in the spleen was more robust among those animals that deteriorated after DTH testing and there were more CD4
+
lymphocytes in the penumbral region of animals with a Th1 response to myelin basic protein.

Conclusions—

Our data suggest that an immune response to the brain contributes to the phenomenon of anamnestic recall of stroke-related deficits after an infection. The contribution of the immune response to this phenomenon deserves further investigation.
Testing for Inherited Thrombophilias in Arterial Stroke
Authors: Morris Jane G. , Singh Swaraj , Fisher Marc
Published: October 2010

Background and Purpose—

Despite a paucity of evidence supporting a true association of ischemic stroke and the inherited thrombophilias, it is common practice for many neurologists to order these tests as part of the work-up of ischemic stroke, especially in young patients. Treatment with oral anticoagulation is often used in patients with positive results for the inherited thrombophilias.

Methods—

We reviewed the literature focusing on case-control studies of the 5 most commonly inherited disorders of coagulation: protein C deficiency, protein S deficiency, antithrombin deficiency, and the factor V Leiden and prothrombin gene mutations in patients with stroke. We also analyzed the available data on stroke patients with inherited thrombophilia and patent foramen ovale.

Results—

Multiple case-control studies have not convincingly shown an association of the inherited thrombophilias with ischemic stroke, even in young patients and patients with patent foramen ovale.

Conclusion—

If there is an association between the inherited thrombophilias and arterial stroke, then it is a weak one, likely enhanced by other prothrombotic risk factors. The consequences of ordering these tests and attributing causality to an arterial event can result in significant costs to the health care system and pose a potential risk to patients, because this may lead to inappropriate use of long-term oral anticoagulants, exposing patients to harm without a clearly defined benefit.
White Matter Hyperintensity Burden and Susceptibility to Cerebral Ischemia
Authors: Rost Natalia S. , Fitzpatrick Kaitlin , Biffi Alessandro , Kanakis Allison , Devan William , Anderson Christopher D. , Cortellini Lynelle , Furie Karen L. , Rosand Jonathan
Published: October 2010

Background and Purpose—

White matter hyperintensity (WMH) burden increases risk of ischemic stroke; furthermore, it predicts infarct growth in acute cerebral ischemia. We hypothesized that WMH would be less severe in patients with TIA as compared to those with acute ischemic stroke and completed infarct.

Methods—

Cases (TIA, n=30) and controls (acute ischemic stroke, n=120) were selected from an ongoing longitudinal cohort study of patients with stroke and matched for age, gender, and race/ethnicity. All subjects had brain MRI within 48 hours of presentation to evaluate for evidence of acute cerebral ischemia. WMH burden on MRI was quantified using a validated computer-assisted program with high inter-rater reliability.

Results—

Median WMH volume in individuals with TIA was 3.7 cm
3
(interquartile range, 1.5- 8.33 cm
3
) compared to 6.9 cm
3
(interquartile range, 3.1–11.9 cm
3
) in acute ischemic stroke (
P
<0.04). In multivariable analysis, the odds of completed infarct were higher (OR, 2.19; 95% CI, 1.27–3.77;
P
<0.005) in subjects with larger volumes of WMH.

Conclusions—

WMH burden was significantly less in subjects with TIA as opposed to those with ischemic stroke. These data provide further evidence to support a detrimental role of WMH burden on the capacity of cerebral tissue to survive acute ischemia.
Understanding Chinese Diplomatic Transformation: A Multi-Actors’ Perspective
Authors: Changhe Su
Published: October 2010

There is growing interest in the role of sub-central actors in Chinese diplomatic evolution. This study explores Chinese diplomatic transformation from the perspective of so-called ‘multi-actors’. It begins with a discussion about the interaction of domestic and international politics, a context where Chinese diplomacy has transformed, and then identifies the roles of local governments, governmental agencies, NGOs and enterprises in China’s changing diplomatic system. The article suggests that these new groups of actors (referred to here as multi-actors) have become important factors to be reckoned with in the Chinese diplomatic system, although their roles are still limited compared with the central government. The article concludes that the establishment of a well-organized diplomatic system, which can be used to coordinate different actors and address transnational issues, will be an enduring challenge for the undergoing reform of the Chinese diplomatic system.
Impact of the Urban Heat Island Effect on Precipitation over a Complex Geographic Environment in Northern Taiwan
Authors: Lin Chuan-Yao , Chen Wan-Chin , Chang Pao-Liang , Sheng Yang-Fan
Published: October 2010

To evaluate the impacts of the urban heat island (UHI) effect on precipitation over a complex geographic environment in northern Taiwan, the next-generation mesoscale model, the Weather Research and Forecasting (WRF) model, coupled with the Noah land surface model and urban canopy model (UCM), was used to study this issue. Based on a better land use classification derived from Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data (the MODIS case), it has significantly improved simulation results for the accumulation rainfall pattern as compared with the original U.S. Geological Survey (USGS) 25-category land use classification (the USGS case). The precipitation system was found to develop later but stronger in the urban (MODIS) case than in the nonurban (USGS) case. In comparison with the observation by radar, simulation results predicted reasonably well; not only was the rainfall system enhanced downwind of the city over the mountainous area, but it also occurred at the upwind plain area in the MODIS case. The simulation results suggested that the correct land use classification is crucial for urban heat island modeling study. The UHI effect plays an important role in perturbing thermal and dynamic processes; it affects the location of thunderstorms and precipitation over the complex geographic environment in northern Taiwan.
Constraints on Climate Sensitivity from Radiation Patterns in Climate Models
Authors: Huber Markus , Mahlstein Irina , Wild Martin , Fasullo John , Knutti Reto
Published: October 2010

The estimated range of climate sensitivity, the equilibrium warming resulting from a doubling of the atmospheric carbon dioxide concentration, has not decreased substantially in past decades. New statistical methods for estimating the climate sensitivity have been proposed and provide a better quantification of relative probabilities of climate sensitivity within the almost canonical range of 2–4.5 K; however, large uncertainties remain, in particular for the upper bound. Simple indices of spatial radiation patterns are used here to establish a relationship between an observable radiative quantity and the equilibrium climate sensitivity. The indices are computed for the Coupled Model Intercomparison Project phase 3 (CMIP3) multimodel dataset and offer a possibility to constrain climate sensitivity by considering radiation patterns in the climate system. High correlations between the indices and climate sensitivity are found, for example, in the cloud radiative forcing of the incoming longwave surface radiation and in the clear-sky component of the incoming surface shortwave flux, the net shortwave surface budget, and the atmospheric shortwave attenuation variable β. The climate sensitivity was estimated from the mean of the indices during the years 1990–99 for the CMIP3 models. The surface radiative flux dataset from the Clouds and the Earth’s Radiant Energy System (CERES) together with its top-of-atmosphere Energy Balanced and Filled equivalent (CERES EBAF) are used as a reference observational dataset, resulting in a best estimate for climate sensitivity of 3.3 K with a likely range of 2.7–4.0 K. A comparison with other satellite and reanalysis datasets show similar likely ranges and best estimates of 1.7–3.8 (3.3 K) [Earth Radiation Budget Experiment (ERBE)], 2.9–3.7 (3.3 K) [International Satellite Cloud Climatology Project radiative surface flux data (ISCCP-FD)], 2.8–4.1 (3.5 K) [NASA’s Modern Era Retrospective-Analysis for Research and Application (MERRA)], 3.0–4.2 (3.6 K) [Japanese 25-yr Reanalysis (JRA-25)], 2.7–3.9 (3.4 K) [European Centre for Medium-Range Weather Forecasts Re-Analysis (ERA-Interim)], 3.0–4.0 (3.5 K) [ERA-40], and 3.1–4.7 (3.6 K) for the NCEP reanalysis. For each individual reference dataset, the results suggest that values for the sensitivity below 1.7 K are not likely to be consistent with observed radiation patterns given the structure of current climate models. For the aggregation of the reference datasets, the climate sensitivity is not likely to be below 2.9 K within the framework of this study, whereas values exceeding 4.5 K cannot be excluded from this analysis. While these ranges cannot be interpreted properly in terms of probability, they are consistent with other estimates of climate sensitivity and reaffirm that the current climatology provides a strong constraint on the lower bound of climate sensitivity even in a set of structurally different models.
Hysteresis Behavior of the Atlantic Ocean Circulation Identified in Observational Data
Authors: Dima Mihai , Lohmann Gerrit
Published: October 2010

On the basis of the multidecadal component of a Fram Strait sea ice export reconstruction and on a sea surface temperature proxy for changes in the ocean circulation, a bifurcation diagram for two cycles of the Atlantic Ocean multidecadal oscillation is constructed. It suggests a hysteresis behavior that is consistent with nonlinear convective adjustment to changes in deep-water formation in the North Atlantic and with the meridional overturning circulation bistability associated with two distinct configurations of the North Atlantic subpolar gyre, simulated in response to idealized carbon dioxide increase. The nonlinear dynamics of the Atlantic Ocean circulation emphasized here on the basis of observational data adds to the hysteresis behavior shown in theoretical and numerical studies.
On the Persistence of Cold-Season SST Anomalies Associated with the Annular Modes
Authors: Ciasto Laura M. , Alexander Michael A. , Deser Clara , England Matthew H.
Published: October 2010

In this study, a simple stochastic climate model is used to examine the impact of the ocean mixed layer depth, surface turbulent energy fluxes, and Ekman currents on the persistence of cold-season extratropical sea surface temperature (SST) anomalies associated with variability in the annular modes of atmospheric circulation in both hemispheres. Observational analysis reveals that during the cold season, SST anomalies associated with the southern annular mode (SSTSAM) persist considerably longer than those associated with the northern annular mode (SSTNAM). Using the simple model, it is shown that the persistence of the cold-season SSTSAM is consistent with the simple stochastic climate paradigm in which the atmospheric forcing is approximated as white noise, and the persistence of SST anomalies can be largely determined by the thermal inertia of the ocean mixed layer. In the North Atlantic, however, the simple climate model overestimates the persistence of the cold-season SSTNAM. It is thought that this overestimate occurs because the NAM-related heat flux forcing cannot be described purely as white noise but must also include a feedback from the underlying SST anomalies.
A GEFA Assessment of Observed Global Ocean Influence on U.S. Precipitation Variability: Attribution to Regional SST Variability Modes
Authors: Zhong Yafang , Liu Zhengyu , Notaro Michael
Published: October 2010

This paper presents a comprehensive assessment of the observed influence of the global ocean on U.S. precipitation variability using the method of Generalized Equilibrium Feedback Assessment (GEFA), which enables an unambiguous attribution of the influence from multiple ocean basins within a unified framework. The GEFA assessment based on observations for 1950–99 suggests that the tropical Pacific SST variability has the greatest consequence for U.S. precipitation, as both ENSO and meridional modes are associated with notable responses in seasonal mean precipitation. The anomalously cold tropical Indian Ocean is a good indicator for U.S. dry conditions during spring and late winter. The impact of North Pacific SST variability is detected in springtime precipitation, yet it is overshadowed by that of the tropical Indo-Pacific on seasonal-to-interannual time scales. Tropical Atlantic forcing of U.S. precipitation appears to be most effective in winter, whereas the northern Atlantic forcing is likely more important during spring and summer.

Global ocean influence on U.S. precipitation is found to be most significant in winter, explaining over 20% of the precipitation variability in the Southwest and southern Great Plains throughout the cold seasons and in the northern Great Plains and northeast United States during late winter. The Southwest and southern Great Plains is likely the region that is most susceptible to oceanic influence, primarily to the forcing of the tropical Indo-Pacific. The Pacific Northwest is among the regions that may experience the least oceanic influence as far as precipitation variability is concerned.
A New Approach to Homogenize Daily Radiosonde Humidity Data
Authors: Dai Aiguo , Wang Junhong , Thorne Peter W. , Parker David E. , Haimberger Leopold , Wang Xiaolan L.
Published: October 2010

Radiosonde humidity records represent the only in situ observations of tropospheric water vapor content with multidecadal length and quasi-global coverage. However, their use has been hampered by ubiquitous and large discontinuities resulting from changes to instrumentation and observing practices. Here a new approach is developed to homogenize historical records of tropospheric (up to 100 hPa) dewpoint depression (DPD), the archived radiosonde humidity parameter. Two statistical tests are used to detect changepoints, which are most apparent in histograms and occurrence frequencies of the daily DPD: a variant of the Kolmogorov–Smirnov (K–S) test for changes in distributions and the penalized maximal F test (PMFred) for mean shifts in the occurrence frequency for different bins of DPD. These tests capture most of the apparent discontinuities in the daily DPD data, with an average of 8.6 changepoints (∼1 changepoint per 5 yr) in each of the analyzed radiosonde records, which begin as early as the 1950s and ended in March 2009. Before applying breakpoint adjustments, artificial sampling effects are first adjusted by estimating missing DPD reports for cold (T < −30°C) and dry (DPD artificially set to 30°C) conditions using empirical relationships at each station between the anomalies of air temperature and vapor pressure derived from recent observations when DPD reports are available under these conditions. Next, the sampling-adjusted DPD is detrended separately for each of the 4–10 quantile categories and then adjusted using a quantile-matching algorithm so that the earlier segments have histograms comparable to that of the latest segment. Neither the changepoint detection nor the adjustment uses a reference series given the stability of the DPD series.

Using this new approach, a homogenized global, twice-daily DPD dataset (available online at www.cgd.ucar.edu/cas/catalog/) is created for climate and other applications based on the Integrated Global Radiosonde Archive (IGRA) and two other data sources. The adjusted-daily DPD has much smaller and spatially more coherent trends during 1973–2008 than the raw data. It implies only small changes in relative humidity in the lower and middle troposphere. When combined with homogenized radiosonde temperature, other atmospheric humidity variables can be calculated, and these exhibit spatially more coherent trends than without the DPD homogenization. The DPD adjustment yields a different pattern of change in humidity parameters compared to the apparent trends from the raw data. The adjusted estimates show an increase in tropospheric water vapor globally.