Evaluation de la tolérance subjective et hémodynamique des membranes de dialyse à faible et haut flux chez les patients sous hémodialyse intermittente chronique : un essai contrôlé randomisé

Les membranes de dialyse à haut flux et à faible flux pourraient être liées à différents profils hemodynamiques pendant les séances de dialyse. Cette étude visait à comparer le profil hémodynamique des certains filtres de dialyse polysulfone couramment utilisés en Suisse. Nous avons réalisé une étude ouverte, cross-over, avec 25 pazients en hémodialyse On a comparés entre eux 4 filtres de polysulfone de la surface de 1 8 m2 A (Revaclear HF, Gambro), B (Helixone HF, Fresenius), C (Xevonta HF, BBraun) et D (Helixone LF Fresenius). Le profil hémodynamique a été mesuré en utilisant une technique non invasive et au patient a été demandé de fournir une opinion sur la tolérance à la seance de dialyse. La même membrane était utilisée pour 3 séances de suites Chaque semaine la membrane de dialyse était modifiée conformément à la séquence de randomisation. Pour chaque patient on a recueillie les données de 12 séances de dialyse. L'étude a été réalisé sur trois mois à compter de novembre 2012. Les analyses ont encore une fois montré la supériorité des filtres à haut débit comparés aux filtres à faible débit, et ne tendance à la supériorité du filtre Helixone (haut debit) comparé aux deux autres membranes. Les filtres à faible débit par rapport a ceux a haut debit sont associés ä une pression systolique et diastolique plus élevées a des résistances périphériques plus hautes et à un débit cardiaque plus faible L incidence d'épisodes d'hypotension en dialyse était la suivante: Revaclear HF (A) 70 Helixone HF (B) 87 Xevonta HF 73 (C), Helixone LF (D) 75. Le nombre d'épisodes d hypotension associée au filtre B était supérieure, de manière significative. La membrane à faible flux était associée à une pression artérielle supérieure à celles des membranes de haut flux. La membrane à haut flux Helixone garantie la meilleure efficacité de dialyse. Malheureusement, la même membrane est associée à une augmentation de l'incidence des épisodes d'hypotension, probablement due à un déséquilibré hé à l'efficacité de la dialyse. Malgré ces résultats, la tolérance subjective pour les différents filtres était comparable.

Growth and magnetic characterization of Co nanoparticles obtained by femtosecond pulsed laser deposition.

We present a detailed study on the morphology and magnetic properties of Co nanostructures deposited onto oxidized Si substrates by femtosecond pulsed laser deposition. Generally, Co disks of nanometric dimensions are obtained just above the ablation threshold, with a size distribution characterized by an increasingly larger number of disks as their size diminishes, and with a maximum disk size that depends on the laser power density. In Au/Co/Au structures, in-plane magnetic anisotropy is observed in all cases, with no indication of superparamagnetism regardless of the amount of material or the laser power density. Magnetic force microscopy observations show coexistence of single-domain and vortex states for the magnetic domain structure of the disks. Superconducting quantum interference device magnetometry and x-ray magnetic circular dichroism measurements point to saturation magnetization values lower than the bulk, probably due to partial oxidation of the Co resulting from incomplete coverage by the Au capping layer.

Syntheses of niobium oxide in the presence of magnetic field and determination of physical properties

Now when the technology fast developing it is very important to control the formation of materials with better properties. In the scientific literature there is a number of works describing the influence of magnetic field on the properties and process of formation of materials. The goal of this master's thesis is to analyze the process of electrochemical synthesis of niobium oxide in the present of magnetic field, to compare properties of formed oxide films and to estimate the influence of magnetic field on the process and on the result of synthesis.

Cost-minimization analysis of three decision strategies for cardiac revascularization : results of the "suspected CAD"cohort of the european cardiovascular magnetic resonance registry.

BACKGROUND: Coronary artery disease (CAD) continues to be one of the top public health burden. Perfusion cardiovascular magnetic resonance (CMR) is generally accepted to detect CAD, while data on its cost effectiveness are scarce. Therefore, the goal of the study was to compare the costs of a CMR-guided strategy vs two invasive strategies in a large CMR registry. METHODS: In 3'647 patients with suspected CAD of the EuroCMR-registry (59 centers/18 countries) costs were calculated for diagnostic examinations (CMR, X-ray coronary angiography (CXA) with/without FFR), revascularizations, and complications during a 1-year follow-up. Patients with ischemia-positive CMR underwent an invasive CXA and revascularization at the discretion of the treating physician (=CMR + CXA-strategy). In the hypothetical invasive arm, costs were calculated for an initial CXA and a FFR in vessels with ≥50 % stenoses (=CXA + FFR-strategy) and the same proportion of revascularizations and complications were applied as in the CMR + CXA-strategy. In the CXA-only strategy, costs included those for CXA and for revascularizations of all ≥50 % stenoses. To calculate the proportion of patients with ≥50 % stenoses, the stenosis-FFR relationship from the literature was used. Costs of the three strategies were determined based on a third payer perspective in 4 healthcare systems. RESULTS: Revascularizations were performed in 6.2 %, 4.5 %, and 12.9 % of all patients, patients with atypical chest pain (n = 1'786), and typical angina (n = 582), respectively; whereas complications (=all-cause death and non-fatal infarction) occurred in 1.3 %, 1.1 %, and 1.5 %, respectively. The CMR + CXA-strategy reduced costs by 14 %, 34 %, 27 %, and 24 % in the German, UK, Swiss, and US context, respectively, when compared to the CXA + FFR-strategy; and by 59 %, 52 %, 61 % and 71 %, respectively, versus the CXA-only strategy. In patients with typical angina, cost savings by CMR + CXA vs CXA + FFR were minimal in the German (2.3 %), intermediate in the US and Swiss (11.6 % and 12.8 %, respectively), and remained substantial in the UK (18.9 %) systems. Sensitivity analyses proved the robustness of results. CONCLUSIONS: A CMR + CXA-strategy for patients with suspected CAD provides substantial cost reduction compared to a hypothetical CXA + FFR-strategy in patients with low to intermediate disease prevalence. However, in the subgroup of patients with typical angina, cost savings were only minimal to moderate.

Fat Suppression with Dixon Techniques in Musculoskeletal Magnetic Resonance Imaging: A Pictorial Review.

Dixon techniques are part of the methods used to suppress the signal of fat in MRI. They present many advantages compared with other fat suppression techniques including (1) the robustness of fat signal suppression, (2) the possibility to combine these techniques with all types of sequences (gradient echo, spin echo) and different weightings (T1-, T2-, proton density-, intermediate-weighted sequences), and (3) the availability of images both with and without fat suppression from one single acquisition. These advantages have opened many applications in musculoskeletal imaging. We first review the technical aspects of Dixon techniques including their advantages and disadvantages. We then illustrate their applications for the imaging of different body parts, as well as for tumors, neuromuscular disorders, and the imaging of metallic hardware.

Trapped periosteum in a distal femoral physeal injury: magnetic resonance imaging evaluation

Epiphyseal fractures are frequently associated with knee trauma during sports in children and adolescents. Usually, Salter-Harris types I and II fractures are conservatively treated. However, failed closed reduction of displaced fractures suggest the presence of trapped periosteum, with indication for surgery. The present report describes a case of Salter-Harris type I fracture of the distal femur in a child, complicated with trapped periosteum detected at magnetic resonance imaging.

Magnetic resonance imaging findings of disc-related epidural cysts in nonsurgical and postoperative microdiscectomy patients

OBJECTIVE: To demonstrate five discal cysts with detailed magnetic resonance imaging findings in nonsurgical and following postoperative microdiscectomy. MATERIALS AND METHODS: Five discal cysts in four patients who underwent magnetic resonance imaging were found through a search in our database and referral from a single orthopedic spine surgeon. Computed tomography in two cases and computed tomography discography in one case were also performed. RESULTS: Five discal cysts were present in four patients. Three patients had no history of previous lumbar surgery and the other patient presented with two discal cysts and recurrent symptoms after partial laminectomy and microdiscectomy. All were oval shaped and seated in the anterior epidural space. Four were ventrolateral, and the other one was centrally positioned in the anterior spinal canal. One showed continuity with the central disc following discography. Three were surgically removed. CONCLUSION: Magnetic resonance imaging can easily depict an epidural cyst and the diagnosis of a discal cyst should be raised when an homogeneous ventrolateral epidural cyst contiguous to a mild degenerated disc is identified.