High-resolution magnetic resonance imaging of acute intracranial artery thrombus.

BACKGROUND AND PURPOSE: The development of high-resolution magnetic resonance imaging (HR-MRI) has enabled submillimeter-level evaluation of intracranial artery plaque and luminal thrombus. We sought to investigate the value of HR-MRI in assessing the pathogenesis of acute intracranial artery thrombus. METHODS: We examined the presence of intracranial thrombus on three-dimensional T1-weighted HR-MRI in acute ischemic stroke patients with intracranial artery occlusion on magnetic resonance angiography. We defined two thrombus-related HR-MRI features (peri-thrombus plaque and distal residual flow beyond the thrombus) and analyzed their association with potential embolic sources. RESULTS: Luminal thrombus and a shrunken artery without luminal thrombus were detected in 162 (96.4%) and six (3.6%) of 168 patients with intracranial artery occlusion, respectively. Among 111 patients with culprit major artery thrombus, peri-thrombus plaques were observed in 46.8% and distal residual flow beyond the thrombus in 64.0%. Patients with peri-thrombus plaque had a higher prevalence of diabetes (44.2% vs. 25.4%; p = 0.037), a lower prevalence of potential sources of cardioembolism (0% vs. 16.9%; p = 0.002), and a nonsignificantly lower prevalence of potential embolic sources from extracranial arteries (9.6% vs. 20.3%; p = 0.186) than those without. Patients with distal residual flow beyond the thrombus had a lower prevalence of potential sources of cardioembolism (1.4% vs. 22.5%; p < 0.001) and smaller infarct volumes (5.0 [1.4-12.7] mL vs. 16.6 [2.4-94.6] mL; p = 0.012) than those without. CONCLUSIONS: Our study showed that HR-MRI helps clarify the pathogenesis of acute intracranial artery thrombus. The presence of peri-thrombus plaque and distal residual flow beyond the thrombus favor the stroke mechanism of atherosclerosis rather than cardioembolism.

Increased EEG gamma power under exposure to drug-related cues: a translational index for cue-elicited craving in METH-dependent individuals.

BACKGROUND: This study explored the feasibility of using EEG gamma-band (30-49 Hz) power as an index of cue-elicited craving in METH-dependent individuals. METHODS: Twenty-nine participants dependent on methamphetamine (METH) and 30 healthy participants were instructed to experience a METH-related virtual reality (VR) social environment. RESULTS: Individuals with METH dependence showed significantly stronger self-reported craving and higher gamma power in a VR environment than healthy individuals. In the METH group, the VR environment elicited a significant increase in gamma power compared with the resting state. The METH group then received a VR counterconditioning procedure (VRCP), which was deemed useful in suppressing cue-induced reactivity. After VRCP, participants showed significantly lower self-reported craving scores and gamma power when exposed to drug-related cues than the first time. CONCLUSIONS: These findings suggest that the EEG gamma-band power may be a marker of cue-induced reactivity in patients with METH dependence.

Virtual-reality-based social cognition and interaction training for patients with schizophrenia: A preliminary efficacy study.

Background: Social cognition and interaction training (SCIT) is a psychosocial intervention program for patients with psychosis, designed to improve their social functioning by improving social cognition. Although the feasibility and efficacy of SCIT have been verified, patients with schizophrenia tend to suffer from motivational deficits and low treatment adherence. It has been suggested that using virtual reality (VR) technology might be effective in addressing these issues. In this study, we aimed to develop a VR-based SCIT and compare its efficacy with that of traditional SCIT. Materials and methods: We developed a novel VR-based social cognition and interaction training (VR-SCIT) that combines traditional SCIT (TR-SCIT) intervention with VR technology. Participants were randomly assigned in a 1:1:1 ratio to the VR-SCIT (n = 28), TR-SCIT (n = 30), or waiting-list groups (n = 29). All treatments were combined with treatment-as-usual. Assessments of social cognition (i.e., Chinese version of Face-Affective Identification Task, Chinese version of Social Cognition Screening Questionnaire) and social functioning (i.e., Chinese version of Personal and Social Performance Scale) were administered from baseline to post-intervention. Results: Patients receiving VR-SCIT and TR-SCIT showed a significantly greater improvement on the assessments of emotion perception (Cohen's d was 1.66, 0.55, and 0.10 for VR-SCIT, TR-SCIT, and Waiting-list, respectively), hostile attributional bias (Cohen's d was 0.48, 0.44, and 0.05 for VR-SCIT, TR-SCIT, and Waiting-list, respectively), metacognition (Cohen's d was 1.66, 0.76, and 0.06 for VR-SCIT, TR-SCIT, and waiting-list, respectively), and social functioning (Cohen's d was 1.09, 0.90, and 0.20 for VR-SCIT, TR-SCIT, and waiting-list, respectively) from baseline to post-intervention, compared to those in waiting-list group. Additionally, VR-SCIT showed an advantage over TR-SCIT in improving emotion perception and metacognition with higher treatment compliance. Conclusion: These preliminary findings indicate that VR-SCIT is a feasible and promising method for improving social cognition and social functioning in patients with schizophrenia.

Rational design of benzodifuran-functionalized donor-acceptor covalent organic frameworks for photocatalytic hydrogen evolution from water.

A benzodifuran-based donor-acceptor covalent organic framework was synthesized and employed for efficient simulated sunlight-driven photocatalytic hydrogen evolution from water, which exhibited a superior and steady hydrogen evolution rate of 1390 µmol g-1 h-1 and an outstanding apparent quantum yield (AQY) of 7.8% was obtained at 420 nm.

Synthesis of fulvene-containing boron complexes with aggregation-induced emission and mechanochromic luminescence.

Two donor-acceptor motif fulvene-containing boron complexes were synthesized with fulvene diketonate boron difluoride (FDB) as the organic acceptor. Both difluoroboron complexes present aggregation-induced emission (AIE) properties and cell tracing function with excellent biocompatibility. And mechanochromic luminescence has been accomplished by the synthesis, isolation and characterization of BL2.

A benzothiadiazole-based covalent organic framework for highly efficient visible-light driven hydrogen evolution.

We demonstrate herein a newly designed benzothiadiazole-based covalent organic framework through an imine linkage with high crystallinity, excellent chemical stability and significant light absorption ability, which was further applied as a high-performance platform for efficient visible-light driven hydrogen evolution.

The clinical value of head-neck joint high-resolution vessel wall imaging in ischemic stroke.

BACKGROUND AND PURPOSE: To study the feasibility and clinical utility of head-neck joint high-resolution vessel wall imaging (HNJ-VWI) in the assessment of ischemic stroke. METHODS: We reviewed our institutional HNJ-VWI database. Patients with transient ischemic attack (TIA) or ischemic stroke were included. Abnormal findings of intracranial and/or extracranial artery were assessed on three-dimensional time-of-flight magnetic resonance angiography (3D TOF MRA) and HNJ-VWI modified from high-resolution 3D T1 sequence and classified into three groups including intracranial, extracranial and coexisting based on the locations. Etiologies of stroke were recorded according to Trial of Org 10172 in Acute Stroke Treatment criteria. RESULTS: One hundred and ten consecutive patients were studied. 3D TOF MRA displayed 71.8% (79/110, based on patients) abnormal arteries (stenosis or occlusion) , while HNJ-VWI displayed 96.3% (106/110) abnormal arteries (plaque,wall thickness and occlusion) including four isolated extracranial lesions and ten coexisting lesions. The etiologies of TIA/ischemic stroke included large artery atherosclerosis (80 cases), cerebral small vessel disease (6 cases), cardiogenic (2 cases), dissection (6 cases), vasculitis (4 cases), moyamoya disease (6 cases), others (2 cases) and undetermined (4 cases). For patients with atherosclerosis stroke, re-infarctions were more common in coexisting group than intracranial group (extracranial vs. intracranial vs coexisting: 0% vs. 9.1% vs. 43.7%, p = 0.001). CONCLUSIONS: HNJ-VWI is a feasible and valuable technique in assessment of ischemic stroke by detecting extracranial and intracranial artery abnormalities with one-step scan.

A novel mechanism of ERK1/2 regulation in smooth muscle involving acetylation of the ERK1/2 scaffold IQGAP1.

Ceramide, a bioactive lipid and signaling molecule associated with cardiovascular disease, is known to activate extracellular signal regulated kinases 1 and 2 (ERK1/2). Here, we determined that the effect of ceramide on ERK1/2 is mediated by ceramide signaling on an ERK scaffold protein, IQ motif containing GTPase activating protein 1 (IQGAP1). Experiments were performed with aortic smooth muscle cells using inhibitor screening, small interfering RNA (siRNA), immunoprecipitation (IP), immunoblots and bioinformatics. We report here that C6 ceramide increases serum-stimulated ERK1/2 activation in a manner dependent on the ERK1/2 scaffold IQGAP1. C6 ceramide increases IQGAP1 protein levels by preventing its cleavage. Bioinformatic analysis of the IQGAP1 amino acid sequence revealed potential cleavage sites for proteases of the proprotein convertase family that match the cleavage products. These potential cleavage sites overlap with known motifs for lysine acetylation. Deacetylase inhibitor treatment increased IQGAP1 acetylation and reduced IQGAP1 cleavage. These data are consistent with a model in which IQGAP1 cleavage is regulated by acetylation of the cleavage sites. Activation of ERK1/2 by ceramide, known to increase lysine acetylation, appears to be mediated by acetylation-dependent stabilization of IQGAP1. This novel mechanism could open new possibilities for therapeutic intervention in cardiovascular diseases.

Cortical actin regulation modulates vascular contractility and compliance in veins.

Most cardiovascular research focuses on arterial mechanisms of disease, largely ignoring venous mechanisms. Here we examine ex vivo venous stiffness, spanning tissue to molecular levels, using biomechanics and magnetic microneedle technology, and show for the first time that venous stiffness is regulated by a molecular actin switch within the vascular smooth muscle cell in the wall of the vein. This switch connects the contractile apparatus within the cell to adhesion structures and facilitates stiffening of the vessel wall, regulating blood flow return to the heart. These studies also demonstrate that passive stiffness, the component of total stiffness not attributable to vascular smooth muscle activation, is severalfold lower in venous tissue than in arterial tissue. We show here that the activity of the smooth muscle cells plays a dominant role in determining total venous stiffness and regulating venous return. The literature on arterial mechanics is extensive, but far less is known about mechanisms controlling mechanical properties of veins. We use here a multi-scale approach to identify subcellular sources of venous stiffness. Portal vein tissue displays a severalfold decrease in passive stiffness compared to aortic tissues. The α-adrenergic agonist phenylephrine (PE) increased tissue stress and stiffness, both attenuated by cytochalasin D (CytoD) and PP2, inhibitors of actin polymerization and Src activity, respectively. We quantify, for the first time, cortical cellular stiffness in freshly isolated contractile vascular smooth muscle cells using magnetic microneedle technology. Cortical stiffness is significantly increased by PE and CytoD inhibits this increase but, surprisingly, PP2 does not. No detectable change in focal adhesion size, measured by immunofluorescence of FAK and zyxin, accompanies the PE-induced changes in cortical stiffness. Probing with phospho-specific antibodies confirmed activation of FAK/Src and ERK pathways and caldesmon phosphorylation. Thus, venous tissue stiffness is regulated both at the level of the smooth muscle cell cortex, via cortical actin polymerization, and by downstream smooth muscle effectors of Src/ERK signalling pathways. These findings identify novel potential molecular targets for the modulation of venous capacitance and venous return in health and disease.

Hierarchical scaffolding of an ERK1/2 activation pathway.

BACKGROUND: Scaffold proteins modulate cellular signaling by facilitating assembly of specific signaling pathways. However, there is at present little information if and how scaffold proteins functionally interact with each other. RESULTS: Here, we show that two scaffold proteins, caveolin-1 and IQGAP1, are required for phosphorylation of the actin associated pool of extracellular signal regulated kinase 1 and 2 (ERK1/2) in response to protein kinase C activation. We show by immunofluorescence and proximity ligation assays, that IQGAP1 tethers ERK1/2 to actin filaments. Moreover, siRNA experiments demonstrate that IQGAP1 is required for activation of actin-bound ERK1/2. Caveolin-1 is also necessary for phosphorylation of actin-bound ERK1/2 in response to protein kinase C, but is dispensible for ERK1/2 association with actin. Simultaneous knock down of caveolin-1 and IQGAP1 decreases total phorbol ester-induced ERK1/2 phosphorylation to the same degree as single knock down of either caveolin-1 or IQGAP1, indicating that caveolin-1 and IQGAP1 operate in the same ERK activation pathway. We further show that caveolin-1 knock down, but not IQGAP1 knock down, reduces C-Raf phosphorylation in response to phorbol ester stimulation. CONCLUSIONS: Based on our data, we suggest that caveolin-1 and IQGAP1 assemble distinct signaling modules, which are then linked in a hierarchical arrangement to generate a functional ERK1/2 activation pathway.