Publications by authors named "Oliver Meissner"

The purpose of this study was to determine whether rotational C-arm computed tomography (CT) allows visualization of liver metastases and adds relevant information for radioembolization (RE) treatment planning. Technetium angiography, together with C-arm CT, was performed in 47 patients to determine the feasibility for RE. C-arm CT images were compared with positron emission tomography (PET)/CT images for the detection of liver tumors.

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Background: This study evaluated the ability of endovascular optical coherence tomography (eOCT) to detect qualitative tissue alteration and quantitative changes of vein wall thickness and vein lumen diameter comparing endovenous radiofrequency ablation (RFA) and endovenous laser therapy (ELT) in an established ex vivo model.

Methods: Endoluminal eOCT was performed by means of a new prototype rotating system (System M1, LightLab Imaging Inc, Boston, Mass) with automatic pullback of 1 mm/s. In the course of an eOCT examination of a 50-mm vein segment, 264 electronic cross section images with a spatial resolution of 15 to 20 mum are acquired.

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Endovascular optical coherence tomography (OCT) is a new imaging modality providing histology-like information of the venous wall. Radiofrequency ablation (RFA) and laser therapy (ELT) are accepted alternatives to surgery. This study evaluated OCT for qualitative assessment of venous wall anatomy and tissue alterations after RFA and ELT in bovine venous specimens.

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Background: Both intravascular ultrasound and optical coherence tomography have been purported to accurately detect and characterize coronary atherosclerotic plaque composition. The aim of our study was to directly compare the reproducibility and diagnostic accuracy of optical coherence tomography and intravascular ultrasound for the detection and characterization of coronary plaque composition ex vivo as compared with histology.

Methods And Results: Intravascular ultrasound (20 MHz) and optical coherence tomography imaging was performed in eight heart specimens using motorized pullback.

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The influence of the xanthohumol from Humulus lupulus L. on the binding of muscimol-Alexa Fluor 532 (Mu-Alexa), a fluorescently labeled GABAA receptor agonist, was studied by fluorescence correlation spectroscopy. An incubation of hippocampal neurons with 75 nM of xanthohumol increased the specific Mu-Alexa binding by approximately 17%, which was selectively found in GABAA receptor Mu-Alexa complexes with hindered lateral mobility [D(bound2) = (0.

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Intraluminal optical coherence tomography (OCT) applies coherent light to provide cross-sectional images with a spatial resolution of 10-25 microm. We compared OCT and matching whole-mount histology microscopy sections of porcine upper ureters ex vivo for visualization and delineation of different tissue layers of the ureteral wall. Porcine ureters (six specimens, 24 quadrants) were flushed with normal saline solution prior to insertion of the OCT catheter (diameter, 0.

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Purpose: Intravascular optical coherence tomography (OCT) is a new imaging modality that provides microstructural information on atherosclerotic plaques and has an axial resolution of 10-20 microm. OCT of coronary arteries characterizes different atherosclerotic plaque components by their distinctive signal patterns. Peripheral human arteries were examined ex vivo by means of OCT, and attempts to distinguish among fibrous, lipid-rich, and calcified atherosclerotic plaques were made based on imaging criteria previously established for coronary arteries.

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A simultaneous HPLC separation of the six major kavapyrones and the flavokavins A-C in an ethanolic extract of Piper methysticum was carried out on a Symmetry C18 column. For quantitative determinations of the flavokavins, calibration curves with correlation coefficients between 0.9986 and 0.

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Purpose: To compare a hybrid magnetic resonance (MR) angiography protocol with selective digital subtraction angiography (DSA) in patients with critical limb ischemia.

Materials And Methods: The study was approved by the institutional review board, and written consent was obtained from all patients. Pretreatment DSA and hybrid MR angiography were performed in 19 consecutive patients (15 men, four women; mean age, 69.

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Purpose: The danger of limb loss as a consequence of acute occlusion of infrapopliteal bypasses underscores the requirement for careful patient follow-up. The objective of this study was to determine the agreement and accuracy of contrast material-enhanced moving-table magnetic resonance (MR) angiography and duplex ultrasonography (US) in the assessment of failing bypass grafts. In cases of discrepancy, digital subtraction angiography (DSA) served as the reference standard.

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The objectives of this retrospective study were to determine the technical success, safety, and midterm results of primary stent placement of infrarenal aortic stenosis. Eight stenoses and one occlusion were treated with stent placement after balloon pre-dilation. Primary technical success was achieved in all patients.

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Protoberberine alkaloids from the rhizomes of Corydalis cava were investigated with regard to their influence on the GABA A receptor using radioreceptor assays. Whereas the protoberberine type 2 alkaloids, isoapocavidine, corydaline, tetrahydropalmatine, scoulerine and isocorypalmine, increased the specific [(3)H]BMC-binding in a range of 21 - 49 %, the protoberberine type 1 alkaloids, palmatine, coptisine, dehydroapocavidine, and dehydrocorydaline, had no influence on the binding behaviour of the GABA A receptor. To confirm the modulatory activity of the protoberberine type 2 alkaloids on living cells, GABA A receptor binding studies were performed by fluorescence correlation spectroscopy (FCS) using hippocampal neurons and the fluorescently labelled ligand, muscimol-Alexa (Mu-Alexa).

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Purpose: To establish a magnetic resonance (MR) imaging protocol for noninvasive in-vivo analysis of atherosclerotic femoral artery segments in humans and to compare the results to those of intravascular ultrasonography (IVUS).

Materials And Methods: In seven patients with peripheral arterial occlusive disease, 20 femoral arterial segments per person were examined by high-resolution (HR) MR imaging and IVUS. Comparison was possible in 123 of 140 segments.

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The binding behavior of a fluorescently labeled muscimol derivative to the GABA(A) receptor was analyzed at rat hippocampal neurons by fluorescence correlation spectroscopy. After muscimol had been labeled with the fluorophore Alexa Fluor 532, specific binding constants for binding of the dye-labeled ligand (Mu-Alexa) to the GABA(A) receptor were determined. We found a high specific binding affinity of Mu-Alexa with a K(D) value of 3.

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Objective: The objective of this study was to determine the diagnostic value of half-Fourier single-shot turbo spin-echo (HASTE) sequences in MR imaging of the brain in pediatric patients.

Subjects And Methods: HASTE sequences were performed in 80 infants and children. Two radiologists who were unaware of the patients' medical histories independently reviewed the images for the presence of nine findings: defects of the parenchyma, hypoplasia or agenesis of the corpus callosum, edema, signs of increased intracranial pressure, myelination disorders, migration disorders, malformations, tumors, and widening of spaces of the cerebrospinal fluid.

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