bluuebunny/crossref_metadata_2025 huggingface dataset:
Sudden death in epilepsy: standards of reporting and the value of toxicological analysis
Authors: Barrow Mickhaiel , Roberts Ian S D , Soilleux Elizabeth J
Published: October 2011

The authors audited the value of toxicology/histology and reporting standards in sudden death autopsy cases in individuals with epilepsy/seizures. Of 83 cases with epilepsy/seizures and no macroscopically obvious cause of death, 40 had no history of drug/alcohol abuse. Toxicological analysis was performed in 11/40 (28%) and did not contribute to the cause of death in any. Conversely, in individuals with epilepsy with known drug/alcohol abuse and cases with a history of seizures related to drug/alcohol abuse, toxicological analysis was performed in 17/22 (77%) and 14/21 (67%), contributing to the causes of death in 8/17 (47%) and 10/14 (71%), respectively. Details of seizures were poorly reported, possibly due to a lack of information from the coroner's office, while autopsy findings were recorded diligently. The authors provide an evidence base for the RCPath guidelines and suggest that taking toxicology samples is essential only when there is a history of drug/alcohol abuse or suspicion of overdose.
Investigation of the presence of ESBL‐producing Escherichia coli in the North Wales and West Midlands areas of the UK in 2007 to 2008 using scanning surveillance
Authors: Snow L. C. , Wearing H. , Stephenson B. , Teale C. J. , Coldham N. G.
Published: October 2011

Between November 5, 2007 and November 4, 2008, faecal samples from cattle and sheep submitted for diagnostic purposes to the Aberystwyth and Shrewsbury Veterinary Laboratories Agency (VLA) (now AHVLA) regional laboratories (covering North Wales and the West Midlands) were screened for the presence of Escherichia coli that produces CTX‐M extended‐spectrum β‐lactamase (ESBL) using the selective medium CHROMagar CTX. Samples from 113 farms were tested and eight ESBL‐positive farms identified. Of these, six farms were identified via submissions of cattle faeces and two from sheep. Gene sequencing revealed both group 1 and group 9 CTX‐M enzymes corresponding to CTX‐M‐14, CTX‐M‐14B (group 9) and CTX‐M‐15/28 (group 1). Analysis of these isolates by nanoarray revealed that some were carrying a range of virulence genes including ireA, iroN and prfB, which have been associated with extraintestinal pathogenic E coli, and were multidrug resistant. Geographical analysis with choropleth maps suggested that these CTX‐M genes are relatively widespread in the North Wales and West Midlands study area. This work was carried out concurrently with the running of a VLA ESBL surveillance system, which has subsequently identified many more CTX‐M positive farms in the UK.
Effects of short-term and prolonged bed rest on the vestibulosympathetic reflex
Authors: Dyckman Damian J. , Sauder Charity L. , Ray Chester A.
Published: October 2011

The mechanism(s) for post-bed rest (BR) orthostatic intolerance is equivocal. The vestibulosympathetic reflex contributes to postural blood pressure regulation. It was hypothesized that muscle sympathetic nerve responses to otolith stimulation would be attenuated by prolonged head-down BR. Arterial blood pressure, heart rate, muscle sympathetic nerve activity (MSNA), and peripheral vascular conductance were measured during head-down rotation (HDR; otolith organ stimulation) in the prone posture before and after short-duration (24 h; n = 22) and prolonged (36 ± 1 day; n = 8) BR. Head-up tilt at 80° was performed to assess orthostatic tolerance. After short-duration BR, MSNA responses to HDR were preserved (Δ5 ± 1 bursts/min, Δ53 ± 13% burst frequency, Δ65 ± 13% total activity; P < 0.001). After prolonged BR, MSNA responses to HDR were attenuated ∼50%. MSNA increased by Δ8 ± 2 vs. Δ3 ± 2 bursts/min and Δ83 ± 12 vs. Δ34 ± 22% total activity during HDR before and after prolonged BR, respectively. Moreover, these results were observed in three subjects tested again after 75 ± 1 days of BR. This reduction in MSNA responses to otolith organ stimulation at 5 wk occurred with reductions in head-up tilt duration. These results indicate that prolonged BR (∼5 wk) unlike short-term BR (24 h) attenuates the vestibulosympathetic reflex and possibly contributes to orthostatic intolerance following BR in humans. These results suggest a novel mechanism in the development of orthostatic intolerance in humans.
Regulation of endothelial connexin40 expression by shear stress
Authors: Vorderwülbecke Bernd J. , Maroski Julian , Fiedorowicz Katarzyna , Da Silva-Azevedo Luis , Marki Alex , Pries Axel R. , Zakrzewicz Andreas
Published: October 2011

Endothelial connexin (Cx)40 plays an important role in signal propagation along blood vessel walls, modulating vessel diameter and thereby blood flow. Blood flow, in turn, has been shown to alter endothelial Cx40 expression. However, the timing and shear stress dependence of this relationship have remained unclear, as have the signal transduction pathways involved and the functional implications. Therefore, the aim of this study was to quantify the effects of shear stress on endothelial Cx40 expression, to analyze the role of phosphoinositide 3-kinase (PI3K)/Akt signaling involved, and to assess the possible functional consequences for the adaptation of microvascular networks. First-passage human umbilical vein endothelial cells were exposed to defined shear stress conditions and analyzed for Cx40 using real-time RT-PCR and immunoblot analysis. Shear stress caused long-term induction of Cx40 protein expression, with two short-term mRNA peaks at 4 and 16 h, indicating the dynamic nature of the adaptation process. Maximum shear stress-dependent induction was observed at shear levels between 6 and 10 dyn/cm2. Simulation of this pattern of shear-dependent Cx expression in a vascular adaptation model of a microvascular network led to an improved fit for the simulated results to experimental measurements. Cx40 expression was greatly reduced by inhibiting PI3K or Akt, with PI3K activity being required for basal Cx40 expression and Akt activity taking part in its shear stress-dependent induction.
Visualization and quantification of whole rat heart laminar structure using high-spatial resolution contrast-enhanced MRI
Authors: Gilbert Stephen H. , Benoist David , Benson Alan P. , White Ed , Tanner Steven F. , Holden Arun V. , Dobrzynski Halina , Bernus Olivier , Radjenovic Aleksandra
Published: October 2011

It has been shown by histology that cardiac myocytes are organized into laminae and this structure is important in function, both influencing the spread of electrical activation and enabling myocardial thickening in systole by laminar sliding. We have carried out high-spatial resolution three-dimensional MRI of the ventricular myolaminae of the entire volume of the isolated rat heart after contrast perfusion [dimeglumine gadopentate (Gd-DTPA)]. Four ex vivo rat hearts were perfused with Gd-DTPA and fixative and high-spatial resolution MRI was performed on a 9.4T MRI system. After MRI, cryosectioning followed by histology was performed. Images from MRI and histology were aligned, described, and quantitatively compared. In the three-dimensional MR images we directly show the presence of laminae and demonstrate that these are highly branching and are absent from much of the subepicardium. We visualized these MRI volumes to demonstrate laminar architecture and quantitatively demonstrated that the structural features observed are similar to those imaged in histology. We showed qualitatively and quantitatively that laminar architecture is similar in the four hearts. MRI can be used to image the laminar architecture of ex vivo hearts in three dimensions, and the images produced are qualitatively and quantitatively comparable with histology. We have demonstrated in the rat that: 1) laminar architecture is consistent between hearts; 2) myolaminae are absent from much of the subepicardium; and 3) although localized orthotropy is present throughout the myocardium, tracked myolaminae are branching structures and do not have a discrete identity.
Molecular Pathways: Targeting Proteasomal Protein Degradation in Cancer
Authors: Molineaux Susan M.
Published: October 2011

With the approval by the U.S. Food and Drug Administration of bortezomib for the treatment of multiple myeloma and mantle cell lymphoma, the proteasome was clinically validated as a target in oncology. The proteasome is part of a complex cellular pathway that controls the specificity and rate of degradation of the majority of proteins in the cell. The search for additional drug targets in the proteasomal pathway is ongoing. In parallel, the next generation of proteasome inhibitors, exhibiting some properties distinct from that of bortezomib, are currently being studied in clinical trials. The key question will be whether these distinctions can improve upon the clinical efficacy and safety standards established by bortezomib and refine our understanding of the mechanism by which proteasome inhibitors are effective in the treatment of cancer. Clin Cancer Res; 18(1); 15–20. ©2011 AACR.
Lysophosphatidic Acid Signaling Protects Pulmonary Vasculature From Hypoxia-Induced Remodeling
Authors: Cheng Hsin-Yuan , Dong Anping , Panchatcharam Manikandan , Mueller Paul , Yang Fanmuyi , Li Zhenyu , Mills Gordon , Chun Jerold , Morris Andrew J. , Smyth Susan S.
Published: October 2011

Objective—

Lysophosphatidic acid (LPA) is a bioactive lipid molecule produced by the plasma lysophospholipase D enzyme autotaxin that is present at ≥100 nmol/L in plasma. Local administration of LPA promotes systemic arterial remodeling in rodents. To determine whether LPA contributes to remodeling of the pulmonary vasculature, we examined responses in mice with alterations in LPA signaling and metabolism.

Methods and Results—

Enpp2
+/−
mice, which are heterozygous for the autotaxin-encoding gene and which have reduced expression of autotaxin/lysophospholipase D and approximately half normal plasma LPA, were hyperresponsive to hypoxia-induced vasoconstriction and remodeling, as evidenced by the development of higher right ventricular (RV) systolic pressure, greater decline in peak flow velocity across the pulmonary valve, and a higher percentage of muscularized arterioles. Mice lacking LPA
1
and LPA
2
, 2 LPA receptors abundantly expressed in the vasculature, also had enhanced hypoxia-induced pulmonary remodeling. With age,
Lpar1
−/−
2
−/−
mice spontaneously developed elevated RV systolic pressure and RV hypertrophy that was not observed in
Lpar1
−/−
mice or
Lpar2
−/−
mice. Expression of endothelin-1, a potent vasoconstrictor, was elevated in lungs of
Lpar1
−/−
2
−/−
mice, and expression of endothelin
B
receptor, which promotes vasodilation and clears endothelin, was reduced in
Enpp2
+/−
and
Lpar1
−/−
2
−/−
mice.

Conclusion—

Our findings indicate that LPA may negatively regulate pulmonary vascular pressure through LPA
1
and LPA
2
receptors and that in the absence of LPA signaling, upregulation in the endothelin system favors remodeling.
Overexpression of Tissue Inhibitor of Metalloproteinase 3 in Macrophages Reduces Atherosclerosis in Low-Density Lipoprotein Receptor Knockout Mice
Authors: Casagrande Viviana , Menghini Rossella , Menini Stefano , Marino Arianna , Marchetti Valentina , Cavalera Michele , Fabrizi Marta , Hribal Marta L. , Pugliese Giuseppe , Gentileschi Paolo , Schillaci Orazio , Porzio Ottavia , Lauro Davide , Sbraccia Paolo , Lauro Renato , Federici Massimo
Published: October 2011

Objective—

Tissue inhibitor of metalloproteinase 3 (TIMP3) is a stromal protein that inhibits the activity of proteases and receptors. TIMP3 is downregulated in metabolic and inflammatory disorders, such as type 2 diabetes mellitus and atherosclerosis, particularly in regions enriched with monocyte/macrophage cells. To investigate the role of TIMP3 in atherosclerosis, we generated a new mouse model in which
Timp3
was overexpressed in the atherosclerotic plaque via a macrophage-specific promoter (MacT3). We elucidated any potential antiatherosclerotic effects of TIMP3, including regulation of monocyte/macrophage recruitment within atherosclerotic plaques, in MacT3 mice crossbred with low-density lipoprotein receptor knockout (LDLR
−/−
) mice.

Methods and Results—

MacT3/LDLR
−/−
mice had an improvement of atherosclerosis and metabolic parameters compared with LDLR
−/−
.
En face
aorta and aortic root examination of MacT3/LDLR
−/−
mice revealed smaller atherosclerotic plaques with features of stability, such as increased collagen content and decreased necrotic core formation. Atherosclerotic plaques in MacT3/LDLR
−/−
mice contained fewer T cells and macrophages. Furthermore, TIMP3 overexpression in macrophages resulted in reduced oxidative stress signals, as evidenced by lower lipid peroxidation, protein carbonylation, and nitration in atheromas.

Conclusion—

Our study confirmed that macrophage-specific overexpression of TIMP3 decreases the inflammatory content and the amplitude of atherosclerotic plaques in mice.
Disruption of Endothelial Peroxisome Proliferator-Activated Receptor γ Accelerates Diet-Induced Atherogenesis in LDL Receptor-Null Mice
Authors: Qu Aijuan , Shah Yatrik M. , Manna Soumen K. , Gonzalez Frank J.
Published: October 2011

Objective—

Peroxisome proliferator-activated receptor γ (PPARγ) is widely expressed in vessel walls, and it's activation by agonists showed beneficial effects in cardiovascular diseases. However, the role of endothelial cell (EC) PPARγ in atherogenesis is not fully understood.

Methods and Results—

To assess the contribution of endothelial-specific PPARγ in atherosclerosis, EC-specific PPARγ disruption and LDL receptor (LDLR) double-knockout (PPARγ
ΔEC
/LDLR
−/−
) mice were developed. When challenged with a high-cholesterol diet for 4 weeks, PPARγ
ΔEC
/LDLR
−/−
mice exhibited severe atherosclerotic lesions compared to either their littermate controls or macrophage-specific PPARγ disruption and LDLR double knockout (PPARγ
ΔMΦ
/LDLR
−/−
) mice. Metabolic analysis showed severe dyslipidemia and significant increase in systolic blood pressure in the PPARγ
ΔEC
/LDLR
−/−
mice. Histological analysis and real-time quantitative PCR suggested an exacerbated inflammation in PPARγ
ΔEC
/LDLR
−/−
mice, as revealed by the increases of proinflammatory gene expression and macrophage infiltration in vivo and in vitro. Furthermore, in vivo endothelial permeability was also increased by endothelial PPARγ disruption. Bone-marrow transplantation studies, which reconstituted hematopoietic PPARγ, demonstrated that the accelerated atherogenesis was due to endothelial PPARγ deficiency.

Conclusion—

Endothelial PPARγ plays an important protective role in atherogenesis.
Nitrite-Mediated
S
-Nitrosylation of Caspase-3 Prevents Hypoxia-Induced Endothelial Barrier Dysfunction
Authors: Lai Yen-Chun , Pan Kuan-Ting , Chang Gao-Fong , Hsu Chia-Hao , Khoo Kay-Hooi , Hung Chen-Hsiung , Jiang Yun-Jin , Ho Feng-Ming , Meng Tzu-Ching
Published: October 2011

Rationale:

Hypoxia is a significant perturbation that exacerbates endothelial barrier dysfunction, contributing to the disruption of vascular homeostasis and the development of various diseases such as atherosclerosis and metastasis of tumors. To date, it is not known what strategy might be used to counter the effect of hypoxia on endothelial permeability.

Objective:

This study investigated the role of nitrite in regulating vascular integrity under hypoxic conditions.

Methods and Results:

We found denitrosylation and the resulting activation of caspase-3 to be critical for hypoxia-induced endothelial permeability. Nitrite treatment led to
S
-nitrosylation and the inactivation of caspase-3, suppressing the barrier dysfunction of endothelia caused by hypoxia. This process required the conversion of nitrite to bioactive nitric oxide in a nitrite reductase-dependent manner. Using primary human umbilical vein endothelial cells as a model, we showed that in the presence of nitrite, the
S
-nitrosylated and inactivated form of caspase-3 was unable to cleave β-catenin, a key component in the VE-cadherin complex. Therefore, nitrite treatment led to the maintenance of VE-cadherin–mediated adherens junctions under hypoxic conditions. In in vivo experiments using a zebrafish model, nitrite was found to protect blood vessels from hypoxia-induced vascular leakage.

Conclusions:

These results are the first to demonstrate that nitrite plays a critical role in the protection of endothelial barrier function against hypoxic insult. Our findings show that nitrite holds great potential for the treatment of diseases associated with hypoxia-induced disorder of vascular homeostasis.
Moyamoya Disease in China
Authors: Duan Lian , Bao Xiang-Yang , Yang Wei-Zhong , Shi Wan-Chao , Li De-Sheng , Zhang Zheng-Shan , Zong Rui , Han Cong , Zhao Feng , Feng Jie
Published: October 2011

Background and Purpose—

Here we describe the clinical features and outcomes of patients with moyamoya disease who were surgically treated at a single institution in China.

Methods—

Our cohort included 802 patients with moyamoya disease. Demographic and clinical characteristics were obtained by retrospective chart review; follow-up information and outcome were obtained through clinical visits, telephone, or letter interview. We used the Kaplan-Meier methods to estimate stroke risk by treatment status.

Results—

The median age for the onset of symptoms was 28 (range, 0.5–77) years. Two definite peaks in age distribution were found. The ratio of women to men was 1:1 (398/404). Familial occurrence of moyamoya disease was 5.2%. The initial symptom was ischemia, hemorrhage, or others in 564, 113, and 125 patients, respectively. Twenty-nine of the 802 patients (3.6%) received conservative management. The remaining 773 patients (96.4%) underwent neurosurgical revascularization procedures, and 502 of these were bilateral. The median follow-up after surgery (n=773) or conservative management (n=26) was 26.3 months (range, 6.0–101.9 months). Most subsequent ischemic events appeared in the first 2 years after surgery. The Kaplan-Meier estimated stroke risk was 10.1% in the first 2 years, and the 5-year-Kaplan-Meier risk of stroke was 12.7% after surgery for all patients treated with surgical revascularization.

Conclusions—

This study on the clinical features of moyamoya disease in mainland China indicated bimodal incidence distribution with women-to-men ratios of 1:1 and lower rate of hemorrhages in adults compared with in children. Patients had low rates of postoperative ischemic or hemorrhagic strokes, and the majority of patients had preserved functional status after revascularization.
Successful Regeneration After Experimental Stroke by Granulocyte-Colony Stimulating Factor Is Not Further Enhanced by Constraint-Induced Movement Therapy Either in Concurrent or in Sequential Combination Therapy
Authors: Diederich Kai , Quennet Verena , Bauer Henrike , Müller Harald D. , Wersching Heike , Schäbitz Wolf-Rüdiger , Minnerup Jens , Sommer Clemens
Published: October 2011

Background and Purpose—

Both application of granulocyte-colony stimulating factor (G-CSF) and constraint-induced movement therapy (CIMT) have been shown to improve outcome after experimental stroke. The aim of the present study was to determine whether concurrent or sequential combination of both therapies will further enhance therapeutic benefit and whether specific modifications in the abundance of various neurotransmitter receptors do occur.

Methods—

Adult male Wistar rats were subjected to photothrombotic ischemia and assigned to the following treatment groups (n=20 each): (1) ischemic control (saline); (2) CIMT (CIMT between poststroke Days 2 and 11; (3) G-CSF (10 μg/kg G-CSF daily between poststroke Days 2 and 11; (4) combined concurrent group (CIMT plus 10 μg/kg G-CSF daily between poststroke Days 2 and 11; and (5) combined sequential group (CIMT between poststroke Days 2 and 11 and 10 μg/kg G-CSF daily between poststroke Days 12 and 21, respectively). Rats were functionally tested before and up to 4 weeks after ischemia. Quantitative receptor autography was performed for
N
-methyl-
d
-aspartate, AMPA, and GABA
A
receptors.

Results—

Significant improvement of functional outcome was seen in all groups treated with G-CSF alone and in either combination with CIMT, whereas CIMT alone failed to enhance recovery. Infarct sizes and remaining cortical tissue did not differ in the various treatment groups. Failure of significant benefit in the CIMT group was associated with a shift toward inhibition in perilesional and remote cortical regions.

Conclusions—

Our findings disclose G-CSF as the major player for enhanced recovery after experimental stroke, preventing a shift toward inhibition as seen in the CIMT group.
Does Diffusion Tensor Imaging-Based Tractography at 3 Months of Age Contribute to the Prediction of Motor Outcome After Perinatal Arterial Ischemic Stroke?
Authors: van der Aa Niek E. , Leemans Alexander , Northington Frances J. , van Straaten Henrica L. , van Haastert Ingrid C. , Groenendaal Floris , Benders Manon J.N.L. , de Vries Linda S.
Published: October 2011

Background and Purpose—

After perinatal arterial ischemic stroke, diffusion-weighted imaging (DWI) and early evaluation of spontaneous motor behavior can be used to predict the development of unilateral motor deficits. The aim of this study was to investigate whether diffusion tensor imaging-based tractography at 3 months of age contributes to this prediction.

Methods—

Twenty-two infants with unilateral perinatal arterial ischemic stroke were included and scanned during the neonatal period. DWI was used to assess restricted diffusion in the cerebral peduncle. At the age of 3 months, diffusion tensor imaging-based tractography of the corticospinal tracts was performed along with assessment of the movement repertoire. The role of DWI, diffusion tensor imaging, and motor assessment in predicting unilateral motor deficits were compared by calculating the positive and negative predictive values for each assessment.

Results—

Eleven infants (50%) showed abnormal motor behavior at 3 months with subsequent development of unilateral motor deficits in 8 as determined at follow-up (9–48 months, positive predictive value 73%). Diffusion tensor imaging-based tractography correctly predicted the development of unilateral motor deficits in all 8 infants (positive predictive value 100%). A diagnostic neonatal DWI was available in 20 of 22 (91%) infants. Seven infants showed an abnormal DWI, resulting in unilateral motor deficits in 6 infants (positive predictive value 86%). All assessments had a negative predictive value of 100%.

Conclusions—

Diffusion tensor imaging-based tractography at 3 months can be used to predict neurodevelopmental outcome after perinatal arterial ischemic stroke. It has a similar predictive value as DWI in the neonatal period and can especially be of additional value in case of an indecisive neonatal DWI or unexpected abnormal early motor development.
Rapid Conditioning With Oxygen Oscillation
Authors: Liu Changsuo , Weaver John , Liu Ke Jian
Published: October 2011

Background and Purpose—

Normobaric hyperoxia (NBO) has been shown to exert neuroprotective effects against cerebral ischemia and to restore penumbral oxygenation. Inspired by recent reports on postconditioning with intermittent occlusions of cerebral artery, we tested the hypothesis that intermittent NBO (iNBO) may cause oscillation of cerebral oxygenation and thereby elicit repetitive interruptions to reperfusion, leading to attenuated ischemia/reperfusion damage after transient focal cerebral ischemia in rats.

Methods—

Rats were subjected to 90 minutes of middle cerebral artery occlusion. During ischemia, animals received air, iNBO (4 cycles of 3 minutes of NBO and 2 minutes of air), continuous NBO (cNBO; 75 minutes), short NBO (18 minutes), or a combination of iNBO and cNBO. Infarct volume and neurological score were evaluated at 24 and 72 hours after ischemia. Production of superoxide was assessed by the hydroethidine method, and the expression of Akt and phosphorylated Akt was examined by Western blot.

Results—

iNBO and cNBO had similar effects in reducing infarct volume and neurological deficit at 24 hours after ischemia, whereas at 72 hours the neuroprotection exerted by iNBO was greater than cNBO. Combining iNBO and cNBO produced no greater protection, and short NBO failed to provide neuroprotection. Both iNBO and cNBO attenuated superoxide production. Importantly, prolonged activation of Akt was observed in the iNBO group, and neuroprotection by iNBO was partly eliminated by inhibition of Akt activation.

Conclusions—

iNBO may represent a novel form of postconditioning, and this neuroprotection is likely mediated by attenuating superoxide generation and activation of the Akt pathway.
Direct Thrombus Imaging as a Means to Control the Variability of Mouse Embolic Infarct Models
Authors: Kim Dong-Eog , Kim Jeong-Yeon , Nahrendorf Matthias , Lee Su-Kyoung , Ryu Ju Hee , Kim Kwangmeyung , Kwon Ick Chan , Schellingerhout Dawid
Published: October 2011

Background and Purpose—

High experimental variability in mouse embolic stroke models could mask the effects of experimental treatments. We hypothesized that imaging thrombus directly would allow this variability to be controlled.

Methods—

We optically labeled thrombi with a near-infrared fluorescent (NIRF) probe C15 that is covalently linked to fibrin by factor-XIIIa. Labeled thrombus was injected into the left distal internal carotid artery (ICA) of C57/BL6 mice (n=47), near its bifurcation, and laser-Doppler cerebral-blood-flow (CBF) was assessed for 30 minutes. NIRF thrombus imaging was done ex vivo at 24 hours.

Results—

CBF variably decreased to 43.9±17.3% at 5 minutes (rCBF; 11.2∼80.4%). NIRF thrombus imaging at 24 hours showed variability in distribution (ICA bifurcation, adjacent and/or remote areas) and burden (2279±1270 pixels; 0∼5940 pixels). Final infarct size was also variable (21.0±10.3%; 4.7∼60.3% of the bihemispheric volume). Despite this heterogeneity, a strong thrombus-infarct correlation was maintained. The left hemispheric target infarct size (% of the hemisphere) correlated with thrombus burden, as a stronger predictor of infarct volume (
P
<0.001, r=0.50) than rCBF (
P
=0.02, r=−0.34). The infarct size was best predicted by a combination of thrombus imaging and CBF: left-hemispheric big-thrombi (>1865 pixels)/low-rCBF (≤42%) had an infarct volume of 56.9±10.4% (n=12), big-thrombi/high-rCBF had 45.9±23.5% (n=11), small-thrombi/low-rCBF 35.7±17.3% (n=11) and small-thrombi/ high-rCBF 27.3±16.4% (n=12).

Conclusions—

This is the first study to demonstrate that the highly heterogeneous nature of the mouse embolic stroke model can be characterized and managed by using near-infrared fluorescent thrombus imaging combined with CBF monitoring to stratify animals into useful subgroups.
Depression and Risk of Stroke
Authors: Dong Jia-Yi , Zhang Yong-Hong , Tong Jian , Qin Li-Qiang
Published: October 2011

Background and Purpose—

A history of depression may be associated with an increased risk of stroke. We aimed to determine the association between depression and risk of stroke by performing a meta-analysis of prospective studies.

Methods—

Relevant studies were identified by a PubMed database search through May 2011 without restrictions and by reviewing reference lists of obtained articles. Community-based or population-based prospective studies that reported relative risk estimates with 95% confidence intervals for the association between depression and stroke were selected. Studies that enrolled participants with preexisting stroke at baseline were excluded. A random-effects model was used to compute the pooled risk estimate.

Results—

Random-effects meta-analysis of 17 prospective studies involving 206 641 participants and 6086 cases demonstrated a significant positive association between depression and subsequent risk of stroke (pooled relative risk, 1.34; 95% confidence interval, 1.17–1.54) after adjustment for potential confounding factors. The associations were similar between men and women. Potential publication bias may exist, but correction for this bias using a formal statistical method did not materially alter the combined risk estimate.

Conclusions—

Depression significantly increased the risk of development of stroke, and this increase was probably independent of other risk factors, including hypertension and diabetes.
Cannabinoid Type 2 Receptor Activation Downregulates Stroke-Induced Classic and Alternative Brain Macrophage/Microglial Activation Concomitant to Neuroprotection
Authors: Zarruk Juan G. , Fernández-López David , García-Yébenes Isaac , García-Gutiérrez María S. , Vivancos José , Nombela Florentino , Torres Magdalena , Burguete María C. , Manzanares Jorge , Lizasoain Ignacio , Moro María A.
Published: October 2011

Background and Purpose—

Ischemic stroke continues to be one of the main causes of death worldwide. Inflammation accounts for a large part of damage in this pathology. The cannabinoid type 2 receptor (CB2R) has been proposed to have neuroprotective properties in neurological diseases. Therefore, our aim was to determine the effects of the activation of CB2R on infarct outcome and on ischemia-induced brain expression of classic and alternative markers of macrophage/microglial activation.

Methods—

Swiss wild-type and CB2R knockout male mice were subjected to a permanent middle cerebral artery occlusion. Mice were treated with either a CB2R agonist (JWH-133), with or without a CB2R antagonist (SR144528) or vehicle. Infarct outcome was determined by measuring infarct volume and neurological outcome. An additional group of animals was used to assess mRNA and protein expression of CB2R, interleukin (IL)-1β, IL-6, tumor necrosis factor α (TNF-α), monocyte chemoattractant protein–1 (MCP-1), macrophage inflammatory peptide (MIP) –1α, RANTES, inducible nitric oxide synthase (iNOS), cyclooxygenase-2, IL-4, IL-10, transforming growth factor β (TGF-β), arginase I, and Ym1.

Results—

Administration of JWH-133 significantly improved infarct outcome, as shown by a reduction in brain infarction and neurological impairment. This effect was reversed by the CB2R antagonist and was absent in CB2R knockout mice. Concomitantly, administration of JWH-133 led to a lower intensity of Iba1+ microglia/macrophages and a decrease in middle cerebral artery occlusion–induced gene expression of both classic (IL-6, TNF-α, MCP-1, MIP-1α, RANTES, and iNOS) and alternative mediators/markers (IL-10, TGF-β, and Ym1) of microglial/macrophage activation after permanent middle cerebral artery occlusion.

Conclusions—

The inhibitory effect of CB2R on the activation of different subpopulations of microglia/macrophages may account for the protective effect of the selective CB2R agonist JWH-133 after stroke.
The Use of Blood Biomarkers to Predict Poor Outcome After Acute Transient Ischemic Attack or Ischemic Stroke
Authors: Whiteley William , Wardlaw Joanna , Dennis Martin , Lowe Gordon , Rumley Ann , Sattar Naveed , Welsh Paul , Green Alison , Andrews Mary , Sandercock Peter
Published: October 2011

Background and Purpose—

The prediction of death or disability (“poor outcome”) after stroke by validated clinical models might be improved by the addition of blood biomarker measurements. We investigated whether such measurements improved the classification of patients into 4 categories of predicted risk of poor outcome: very high, intermediate high, intermediate low, and very low.

Methods—

We prospectively recruited symptomatic patients within 24 hours of ischemic cerebrovascular events. We measured clinical prognostic variables in each patient. We drew blood soon after admission and measured markers of inflammation, thrombosis, cardiac strain, and cerebral damage. We assessed poor outcome at 3 months with the modified Rankin Scale and recovery of symptoms at 24 hours. We measured the association between blood marker levels and poor outcome after adjustment for stroke severity and age with multivariate logistic regression. Where these associations were statistically significant, we calculated the net reclassification index.

Results—

We recruited 270 patients with acute ischemic cerebrovascular events. At 3 months, 112 patients had a poor outcome. After adjustment for stroke severity and age, only interleukin-6 and N-terminal pro-brain natriuretic peptide were significantly associated with poor outcome. The addition of either interleukin-6 or N-terminal pro-brain natriuretic peptide to National Institutes of Health Stroke Scale and age did not improve the prediction of a poor outcome.

Conclusions—

Neither interleukin-6 nor N-terminal pro-brain natriuretic peptide had sufficient predictive power to be of clinical use to predict poor outcome after stroke. The search for better markers to improve the classification of patients across clinically relevant boundaries of predicted probabilities of outcome events needs to continue.
Pilot and Feasibility Test of Adolescent-Controlled Text Messaging Reminders
Authors: Britto Maria T. , Munafo Jennifer Knopf , Schoettker Pamela J. , Vockell Anna-Liisa B. , Wimberg Janet A. , Yi Michael S.
Published: October 2011

Purpose. This pilot study assessed the feasibility, acceptability, and utility of a text messaging system that allowed teenagers with asthma to generate and control medical reminders sent to their mobile phones. Methods. The 12 teens in the study group were able to create their own reminder text messages, add or change reminders, and determine when and how often the messages were sent to their cell phone. Results. In total, 18 of the 21 unique messages created were reminders to take medication. No teen made changes to their original text messages or delivery schedule on their own. They gave high ratings on the usefulness, acceptability, and ease of use of the text messaging system. Self-reported asthma control at baseline was similar for both the study and comparison groups and did not change significantly. Conclusions. Allowing teens to control the timing and content of reminder text messages may support self-management of chronic disease.
Vitamin D Insufficiency Is Associated With Diabetes Risk in Native American Children
Authors: Nsiah-Kumi Phyllis A. , Erickson Judi M. , Beals Jennifer L. , Ogle Eric A. , Whiting Mary , Brushbreaker Connie , Borgeson Claudia D. , Qiu Fang , Yu Fang , Larsen Jennifer L.
Published: October 2011

Aims/Hypothesis. Vitamin D insufficiency has not been well studied in Native American (NA) children, who are at risk for obesity and diabetes. The authors examined vitamin D insufficiency and its association with body mass index (BMI) and insulin resistance. Methods. In a cross-section of NA children 5 to 18 years old (N = 198), anthropometrics, biomarkers of insulin resistance, and 25-hydroxy-vitamin D concentration [25(OH) vitamin D] were measured. BMI% and homeostatic model assessment of insulin resistance (HOMA-IR) were calculated. Results. Mean age was 10.8 ± 0.3 years (mean ± SEM). Mean serum 25(OH) vitamin D was 17.8 ± 0.4 ng/mL and 97% had vitamin D insufficiency [25(OH) vitamin D <30 ng/mL]. After adjusting for BMI, 25(OH) vitamin D was inversely associated with HOMA-IR ( P < .0001) and several other markers of insulin resistance. Conclusions/Interpretation. Vitamin D insufficiency was nearly universal in this cohort of NA children and was associated with diabetes and vascular risk markers. Whether vitamin D supplementation can improve insulin resistance must be studied further.
Wayfinding and Spatial Reorientation by Nova Scotia Deer Hunters
Authors: Hill Kenneth A.
Published: October 2011

How do backcountry travelers respond to losing their way? To address this question, deer hunters were surveyed in regard to their attitudes toward various methods of recovering one’s spatial orientation. Ratings of the likelihood of adopting each of nine reorientation strategies—or advice on what to do on becoming “lost” in the woods—revealed that “climbing a tree or hill for a better view” was rated highest among alternatives. One strategy, “try to travel a straight line out of the woods,” was positively correlated with respondents’ self-reports of having been lost while hunting. Principal components analysis of reorientation strategies yielded four components, labeled “skill based” (e.g., using environmental cues to travel a straight line), “downhill” (e.g., following a stream), “perception based” (improving visual access), and “wandering” (e.g., traveling the path of least resistance). The importance of spatial reorientation to general wayfinding skill was discussed.
Personally Relevant Climate Change
Authors: Scannell Leila , Gifford Robert
Published: October 2011

To help mitigate the negative effects of climate change, citizens’ attitudes and behaviors must be better understood. However, little is known about which factors predict engagement with climate change, and which messaging strategies are most effective. A community sample of 324 residents from three regions in British Columbia read information either about a climate change impact relevant to their local area, a more global one, or, in a control condition, no message. Participants indicated the extent of their climate change engagement, the strength of their attachment to their local area, and demographic information. Three significant unique predictors of climate change engagement emerged: place attachment, receiving the local message, and gender (female). These results provide empirical support for some previously proposed barriers to climate action and suggest guidelines for effective climate change communication.
Experimental study of the compaction response of jute fabrics in liquid composite molding processes
Authors: Francucci Gastón , Rodríguez Exequiel S. , Vázquez Analía
Published: October 2011

The aim of this work is to characterize the compaction behavior of jute woven fabric preforms. The maximum compaction pressure, permanent deformation, and stress relaxation of the preforms were found to be dependent on the final fiber volume fraction and the compaction speed. Higher compaction speeds led to higher compaction pressures, stress relaxation, and permanent deformation. On the other hand, as the fiber content was raised, the maximum compaction pressure and the permanent deformation increased, while the stress relaxation decreased. In addition, it was found that the structure of natural fibers affected the compaction behavior of the preforms. Each fiber is composed of several hollow elementary fibers, which collapsed due to the compressive loading. Furthermore it was found that fluid absorption reduced the compaction pressure in natural fiber preforms due to fiber softening.
Experimental investigation and analysis in turning of CFRP composites
Authors: Rajasekaran T , Palanikumar K , Vinayagam BK
Published: October 2011

Carbon fiber-reinforced composite materials are finding increased application in many areas. Machining of these composites cannot be avoided to avail a near-net shape. The study and development of prediction model for cutting force, cutting power, and specific cutting force have been an important area for researchers. Interest toward this subject is increasing due to the factors which restricts from carrying out the experimental studies like the number of machining parameters to be controlled and time taken for machining to determine cutting forces. This study attempts to develop a fuzzy model to predict the cutting force thereby cutting power and specific cutting force. The developed models offer satisfactory performance on comparison with the experimental results and hence these models can be effectively used to predict cutting forces in machining of carbon fiber-reinforced plastic composites.
A rate-independent thermomechanical constitutive model for fiber reinforcements
Authors: Cheng J.J. , Kelly P.A. , Bickerton S.
Published: October 2011

In liquid composite molding (LCM) processes, the constitutive behavior of fibrous reinforcements has a strong bearing on the choice of manufacturing parameters and final part properties. In many LCM processes, the fibrous preform is subjected to loading and unloading, the latter occurring during both filling and postfilling phases of the manufacturing process. Fiber reinforcements display inelastic behavior with rate-dependent and rate-independent components and this must be modeled accurately over several load–unload cycles in order to accurately simulate such processes. An important feature of the material behavior is its unchanging response to successive load cycles once a large number of load cycles has been applied. Inelastic effects such as fiber–fiber frictional sliding occur during loading as well as unloading and the inelastic deformation remaining after successive cycles appears unchanged. The model presented is developed within a thermomechanical framework and reproduces such behavior using a single internal variable to account for inelasticity. It is compared to cyclic loading experiments on three fiber reinforcements of different architecture, showing that the model is effective in capturing the repeatable compaction behavior of debulked preforms and serves as a starting point for the incorporation of effects such as cyclic softening and rate effects through additional internal variables.
A study of the effect of experimental test parameters on data scatter in microbond testing
Authors: Pandey Gajendra , Kareliya Chirag H. , Singh Raman P.
Published: October 2011

This paper evaluates the effect of two experimental parameters, namely microvise blade geometry and blade separation, on the scatter in measured interfacial strength in microbond experiments, with the help of two-dimensional (2D) and three-dimensional (3D) finite element models. The 3D model better captures the ‘exact’ loading nature of the problem as compared to the 2D model but it is computationally intensive. Stress distributions obtained by finite element analysis are compared with those from the shear-lag model often used to analyze microbond experiments. This comparison determines the effectiveness of using shear-lag analysis in microbond experiments and for explaining the reasons for commonly observed data scatter.
The influence of montmorillonite modification on the properties of composite material based on poly(methacrylic acid)
Authors: Nikolic Ljubisa , Ristic Ivan , Stojiljkovic Stanisa , Vukovic Zorica , Stojiljkovic Dragan , Nikolic Vesna , Budinski-Simendic Jaroslava
Published: October 2011

In this work a new class of functional composites was prepared based on the organically modificated montmorillonite and methacrylic acid. In the first step, the native montmorillonite was mixed with poly(ethylenimine) monomer to promote the intercalation process. In the second step, the methacrylic acid and initiator (potassium persulfate) were added and polymerization was carried out at 80°C for 2 hours. Characterization of the obtained composite material was performed by Fourier transform infrared spectroscopy. The change in interlamellar spacing of montmorillonite after polymer composite preparation was determined by X-ray diffraction. In prepared composite samples the existence of two crystalline phases was estimated by X-ray measurements. In the first, the poly(methacrylic acid) chains are intercalated within the montmorillonite layers, and in the second, they are dispersed in the polymer matrix. The influence of montmorillonite on the thermal properties of the obtained composites was measured using the combined thermogravimetry and differential scanning calorimetry method. The porosity of the prepared samples was determined by isotherm adsorption and the desorption of nitrogen (Brunauer–Emmett–Teller method). It was assessed that a certain amount of polymer is deposited on the montmorillonite and thus covering of the micropores and partially covering of the mesopores was achieved.
On the in-plane deformability of cross-plied unidirectional prepreg
Authors: Larberg Ylva R , Åkermo Malin , Norrby Monica
Published: October 2011

The work presented herein aims to investigate the in-plane properties of cross-plied unidirectional prepreg using the bias extension method. The study considers different generations of carbon fibre/epoxy material systems, and testing is performed at elevated temperatures to enhance the deformability. Using digital image correlation, the specimen deformation and fibre rotation is captured during testing. The study shows that most cross-plied unidirectional material deforms at different characteristic length scales as deformation continues: first seemingly continuous and later in the form of bands. Further, the different type of prepreg materials investigated behaves differently; for one type the pin-jointed net theory fit well, enabling simple estimation of the resulting fibre angle, while for the other two it did not. Different loading speeds and temperatures are investigated in order to pinpoint their influence on the deformability.
Comparative analysis of drills for composite laminates
Authors: Durão Luís Miguel P , Gonçalves Daniel JS , Tavares João Manuel RS , de Albuquerque Victor Hugo C , Marques A Torres
Published: October 2011

The characteristics of carbon fiber-reinforced plastics allow a very broad range of uses. Drilling is often necessary to assemble different components, but this can lead to various forms of damage, such as delamination which is the most severe. However, a reduced thrust force can decrease the risk of delamination. In this work, two variables of the drilling process were compared: tool material and geometry, as well as the effect of feed rate and cutting speed. The parameters that were analyzed include: thrust force, delamination extension and mechanical strength through open-hole tensile test, bearing test, and flexural test on drilled plates. The present work shows that a proper combination of all the factors involved in drilling operations, like tool material, tool geometry and cutting parameters, such as feed rate or cutting speed, can lead to the reduction of delamination damage and, consequently, to the enhancement of the mechanical properties of laminated parts in complex structures, evaluated by open-hole, bearing, or flexural tests.
Studies of fiber volume fraction and geometry of variable cross-section tubular 3D five-direction braided fabric
Authors: Ma Wensuo , Zhu Jianxun , Jiang Yun
Published: October 2011

The requirements for the size and performance of fabric 3D five-directional braided variable cross-sectional tube can be met by using the appropriate reducing-yarn technique. Compared with the fabric processed with invariable cross-sectional yarns, the theoretical model of geometric structure and properties of variable cross-sectional yarn fabric is more complex. Based on the constituting method of yarn and the variation law of fabric, fiber volume fraction has changed greatly. The fabric is divided into different zones according to the constituting method of yarn in its unit cell, and the unit geometry models corresponding to different zones are established. The fabric geometry size and fiber volume fraction distribution are predicted. Research result shows that the model can describe the characteristics of braided fabric accurately. Therefore, the model lays theoretical foundation for the fabric structure design of the variable cross-sectional tubular fabric braided in 3D five-directions.
Processing and properties of soy protein/silica nanocomposites fabricated in situ synthesis
Authors: Tian Huafeng
Published: October 2011

Nanocomposite materials were prepared via glycerol plasticized soy protein as the matrix and in situ fabricated silica as thereinforcing phase. The silica nanoparticles were synthesized in the protein environment by sodium silicate as a precursor. The resulting composites were characterized by Fourier transform infrared spectroscopy (FTIR), wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), tensile tests, and thermogravimetric analysis (TGA). The results revealed that silica particles were homogeneously dispersed in soy protein matrix at a nanometer scale with low silica addition (lower than 15%). Silica particles exhibited a high adhesion with protein matrix through hydrogen bonding and confined the motions of soy protein segments. The incorporation of silica as a reinforcing agent significantly improved the mechanical properties and thermal stability of soy protein plastics.