Investigations of vesicle gels by pulsed and modulated gradient NMR diffusion techniques

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Vesicle gels are surfactant systems that form stiff gels with rather low amounts of surfactant. So far their structures have mostly been investigated using scattering techniques, which are generally appropriate for the study of structures on the nm-length-scale. Here we examine these gels using two complementary diffusion NMR techniques, which are both sensitive to structures on the μm-scale. The presented results imply structural features on the μm-scale, indicating a more complex structure than just that of densely packed small vesicles, as previously found for these systems. It is demonstrated that a combination of the diffusion NMR methods, described here, can provide useful insights, when morphological features extend over a wide range of length scales

Mechanical thrombectomy in acute ischemic stroke—experience from 6 years of practice

INTRODUCTION: We present our results from the first 6 years with mechanical thrombectomy in the treatment of ischemic stroke. METHODS: Every patient treated with mechanical thrombectomy for acute ischemic stroke from September 2005 to December 2011 was consecutively included in this retrospective analysis. Baseline and outcome data were retrieved from computerized records at the hospital. National Institute of Health Stroke Scale (NIHSS) score and the modified Rankin Scale (mRS) score were used as outcome parameters. Favorable outcome was defined as a mRS score of 0–2, corresponding to independence in activities of daily living. We also evaluated revascularization and severe adverse events, with focus on symptomatic intracranial hemorrhage. RESULTS: Good functional outcome (mRS 0–2) was achieved in 50 % (120/240) of all patients. For patients with no neurological deficit prior to stroke onset (i.e., mRS = 0 before stroke), the proportion with good functional outcome was 54 %. Symptomatic hemorrhages occurred in 4.6 % of the cases (5.7 % in the anterior circulation). CONCLUSION: In summary, our results supports that mechanical thrombectomy is a safe and effective method to restore blood flow in selected patients suffering from an acute ischemic stroke

Results of an international survey on the investigation and endovascular management of cerebral vasospasm and delayed cerebral ischemia

Background: Delayed cerebral ischemia (DCI) is a major cause of morbidity and mortality in aneurysmal subarachnoid hemorrhage. Endovascular management of this condition offers a new hope in preventing adverse outcome; however, a uniform standard of practice is lacking owing to a paucity of clinical trials. We conducted an international survey on the use of investigative and endovascular techniques in the treatment of DCI to assess the variability of current practice. Methods: Neurovascular neurosurgeons and neuroradiologists were contacted through professional societies from America, United Kingdom, Europe, and Australasia. Members were invited to complete a 13-item questionnaire regarding screening techniques, first-line and second-line therapies in endovascular intervention, and the role of angioplasty. Answers were compared using χ2 testing for nonparametric data. Results: Data from 344 respondents from 32 countries were analyzed: 167 non-United States and 177 U.S. respondents. More than half of all clinicians had 10+ years of experience in units with a mixture of higher and lower case volumes. Daily transcranial Doppler ultrasonography was the most commonly used screening technique by both U.S. (70%) and non-U.S. (53%) practitioners. Verapamil was the most common first-line therapy in the United States, whereas nimodipine was most popular in non-U.S. countries. Angioplasty was performed by 83% of non-U.S. and 91% of U.S. clinicians in the treatment of vasospasm; however, more U.S. clinicians reported using angioplasty for distal vasospasm. Conclusions: Treatment practices for DCI vary considerably, with the greatest variability in the choice of agent for intra-arterial therapy. Our data demonstrate the wide variation of approaches in use at present. However, without further clinical trials and development of a uniform standard of best practice, variability in treatment and outcome for DCI is likely to continue

A methodology for validating a 3D imaging modality for brain AVM delineation: Application to 3DRA.

International audienceA general methodology is described to validate a 3D imaging modality with respect to 2D digital subtracted angiography (DSA) for brain AVMs (BAVM) delineation. It relies on the assessment of the statistical compatibility of the radiosurgical target delineated in 3D with its delineations in 2D. This methodology is demonstrated through a preliminary evaluation of rotational 3D angiography (3DRA). Generally speaking, BAVM delineation cannot be performed on 3DRA alone. However, in our study, 3DRA showed similar performances to DSA for rather easy cases, and even better for 3 patients. Conversely, 3 problematic cases are identified and discussed

International Survey on Criteria for Training and Accreditation in Interventional Neuroradiology

Purpose With the rapid expansion of the field of interventional neuroradiology (INR) and the diverse background of aspiring neuro-interventionists, there is an ever increasing need to establish consensus criteria for training and accreditation in INR.Materials and Methods We performed a survey to explore the current state of criteria for training and accreditation in INR. The questionnaire consisting of 11 questions was emailed to the members of World Federation of Interventional and Therapeutic Neuroradiology (WFITN) worldwide. It was focused on the training charter, training program, qualifying examination, and education after training program as perceived by practitioners in each country. Results A total of 52 WFITN members in 19 countries responded to the questionnaire. There was a huge variation internationally and nationally due to the unique situation and challenges in each country and institution. Criteria for training and accreditation in INR were well established in some countries of Europe, North America, and Asia but not specified in other countries. Conclusion It is critical to establish consensus criteria for training and accreditation in INR in order to ensure safe practice and continued expansion and development of INR as a specialty

High-resolution 3D X-ray imaging of intracranial nitinol stents

Introduction To assess an optimized 3D imaging protocol for intracranial nitinol stents in 3D C-arm flat detector imaging. For this purpose, an image quality simulation and an in vitro study was carried out. Methods Nitinol stents of various brands were placed inside an anthropomorphic head phantom, using iodine contrast. Experiments with objects were preceded by image quality and dose simulations. We varied X-ray imaging parameters in a commercially interventional X-ray system to set 3D image quality in the contrast–noise–sharpness space. Beam quality was varied to evaluate contrast of the stents while keeping absorbed dose below recommended values. Two detector formats were used, paired with an appropriate pixel size and X-ray focus size. Zoomed reconstructions were carried out and snapshot images acquired. High contrast spatial resolution was assessed with a CT phantom. Results We found an optimal protocol for imaging intracranial nitinol stents. Contrast resolution was optimized for nickel–titanium-containing stents. A high spatial resolution larger than 2.1 lp/mm allows struts to be visualized. We obtained images of stents of various brands and a representative set of images is shown. Independent of the make, struts can be imaged with virtually continuous strokes. Measured absorbed doses are shown to be lower than 50 mGy Computed Tomography Dose Index (CTDI). Conclusion By balancing the modulation transfer of the imaging components and tuning the high-contrast imaging capabilities, we have shown that thin nitinol stent wires can be reconstructed with high contrast-to-noise ratio and good detail, while keeping radiation doses within recommended values. Experimental results compare well with imaging simulations

Auchenorrhyncha collected in the Canavese district (Northwest Italy): (Hemiptera, Auchenorrhyncha)

Die Ergebnisse von Zikaden-Sammelexkursionen im Distrikt Canavese (Italien, Piemont) werden präsentiert, die im Rahmen des 14. Auchenorrhyncha-Tagung (07.-09. – 09.09.2007) und des 4. Europäischen Hemipteren-Kongresses (10.09. – 14.09.2007) in Ivrea durchgeführt wurden. Zwei neue Arten für Italien und zahlreiche neue Zikadenarten für Piemont wurden festgestellt.The results of Auchenorrhyncha collection excursions in the Canavese district (Italy, Piedmont) are presented, that were held during the 14th Central European Auchenorrhyncha Meeting (07.09. – 09.09.2007) and the 4th European Hemiptera Congress (10.09.–14.09.2007) in Ivrea are given. Two new species for Italy, and several new species for Piedmont were found

Contribution of copy number variants to schizophrenia from a genome-wide study of 41,321 subjects

Copy number variants (CNVs) have been strongly implicated in the genetic etiology of schizophrenia (SCZ). However, genome-wide investigation of the contribution of CNV to risk has been hampered by limited sample sizes. We sought to address this obstacle by applying a centralized analysis pipeline to a SCZ cohort of 21,094 cases and 20,227 controls. A global enrichment of CNV burden was observed in cases (OR=1.11, P=5.7×10−15), which persisted after excluding loci implicated in previous studies (OR=1.07, P=1.7 ×10−6). CNV burden was enriched for genes associated with synaptic function (OR = 1.68, P = 2.8 ×10−11) and neurobehavioral phenotypes in mouse (OR = 1.18, P= 7.3 ×10−5). Genome-wide significant evidence was obtained for eight loci, including 1q21.1, 2p16.3 (NRXN1), 3q29, 7q11.2, 15q13.3, distal 16p11.2, proximal 16p11.2 and 22q11.2. Suggestive support was found for eight additional candidate susceptibility and protective loci, which consisted predominantly of CNVs mediated by non-allelic homologous recombination

No Reliable Association between Runs of Homozygosity and Schizophrenia in a Well-Powered Replication Study

It is well known that inbreeding increases the risk of recessive monogenic diseases, but it is less certain whether it contributes to the etiology of complex diseases such as schizophrenia. One way to estimate the effects of inbreeding is to examine the association between disease diagnosis and genome-wide autozygosity estimated using runs of homozygosity (ROH) in genome-wide single nucleotide polymorphism arrays. Using data for schizophrenia from the Psychiatric Genomics Consortium (n = 21,868), Keller et al. (2012) estimated that the odds of developing schizophrenia increased by approximately 17% for every additional percent of the genome that is autozygous (β = 16.1, CI(β) = [6.93, 25.7], Z = 3.44, p = 0.0006). Here we describe replication results from 22 independent schizophrenia case-control datasets from the Psychiatric Genomics Consortium (n = 39,830). Using the same ROH calling thresholds and procedures as Keller et al. (2012), we were unable to replicate the significant association between ROH burden and schizophrenia in the independent PGC phase II data, although the effect was in the predicted direction, and the combined (original + replication) dataset yielded an attenuated but significant relationship between Froh and schizophrenia (β = 4.86,CI(β) = [0.90,8.83],Z = 2.40,p = 0.02). Since Keller et al. (2012), several studies reported inconsistent association of ROH burden with complex traits, particularly in case-control data. These conflicting results might suggest that the effects of autozygosity are confounded by various factors, such as socioeconomic status, education, urbanicity, and religiosity, which may be associated with both real inbreeding and the outcome measures of interest

Genetic correlation between amyotrophic lateral sclerosis and schizophrenia

A. Palotie on työryhmän Schizophrenia Working Grp Psychiat jäsen.We have previously shown higher-than-expected rates of schizophrenia in relatives of patients with amyotrophic lateral sclerosis (ALS), suggesting an aetiological relationship between the diseases. Here, we investigate the genetic relationship between ALS and schizophrenia using genome-wide association study data from over 100,000 unique individuals. Using linkage disequilibrium score regression, we estimate the genetic correlation between ALS and schizophrenia to be 14.3% (7.05-21.6; P = 1 x 10(-4)) with schizophrenia polygenic risk scores explaining up to 0.12% of the variance in ALS (P = 8.4 x 10(-7)). A modest increase in comorbidity of ALS and schizophrenia is expected given these findings (odds ratio 1.08-1.26) but this would require very large studies to observe epidemiologically. We identify five potential novel ALS-associated loci using conditional false discovery rate analysis. It is likely that shared neurobiological mechanisms between these two disorders will engender novel hypotheses in future preclinical and clinical studies.Peer reviewe