Publications by authors named "Clemens Mueller"

Using ferric chloride (FeCl3) to induce experimental superior sagittal sinus (SSS) thrombosis might interfere with magnetic resonance imaging (MRI)-assisted visualization and evaluation of the thrombus, the brain parenchyma, and the quality of the occlusion. The aim of this study was to investigate whether aluminum chloride (AlCl3)-induced thrombosis of the SSS has comparable properties to those of FeCl3 without causing artifacts in MRI. SSS thrombosis was induced in 14 male Wistar rats by exposure of the SSS and subsequent topical application of a filter paper strip soaked in AlCl3 (n = 7) or FeCl3 (n = 7) over a period of 15 min.

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Aims: Mammalian models have been instrumental in investigating adult heart function and human disease. However, electrophysiological differences with human hearts and high costs motivate the need for non-mammalian models. The zebrafish is a well-established genetic model to study cardiovascular development and function; however, analysis of cardiovascular phenotypes in adult specimens is particularly challenging as they are opaque.

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Background: Neuromyelitis optica (NMO) is an autoimmune disorder of the central nervous system, which is characterized by autoantibodies directed against the water channel aquaporin-4 (AQP4). As one of the main water regulators in the central nervous system, APQ4 is supposed to be involved in the dynamics of brain edema. Cerebral edema seriously affects clinical outcome after ischemic stroke; we therefore aimed to investigate whether NMO-antibodies may exert the same functional effects as an AQP4-inhibitor in-vivo in acute ischemic stroke.

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In monitoring of recanalization and in sonothrombolysis, contrast-enhanced ultrasound (CEUS) is applied in extended time protocols. As extended use may increase the probability of unwanted effects, careful safety evaluation is required. We investigated the safety profile and beneficial effects of CEUS in a reperfusion model.

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Objectives: Intravenous immunoglobulin (IVIG) is used for treatment of immunodeficiencies and autoimmune disorders. Recently, IVIG has also been shown to reduce infarct size in acute stroke. Since edema treatment can provide secondary neuroprotective effects, we conducted the present study to evaluate whether edema reduction is the underlying cause of the neuroprotective properties of IVIG in experimental stroke.

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Object: Brain edema formation is a serious complication of ischemic stroke and can lead to mechanical compression of adjacent brain structures, cerebral herniation, and death. Furthermore, the space-occupying effect of edema impairs regional cerebral blood flow (rCBF), which is particularly important in the penumbra phase of stroke. In the present study, the authors evaluated the natural course of edema formation in the hyperacute phase of focal cerebral ischemia.

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Ischemic stroke causes cell necrosis with the exposure of extracellular ribonucleic acid (RNA) and other intracellular material. As shown recently, extracellular RNA impaired the blood-brain-barrier and contributed to vasogenic edema-formation. Application of ribonuclease 1 (RNase 1) diminished edema-formation and also reduced lesion volume in experimental stroke.

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Peripheral arteriogenesis is distinctly enhanced by increased fluid shear stress. Thus, the aim of this study was to investigate in the rat brain whether increased fluid shear stress can also stimulate cerebral arteriogenesis. To increase fluid shear stress in the cerebral circulation, we developed different shear stress models as the ligature of both common carotid arteries (Double-Ligature model), bilateral carotid ligature followed by creation of a unilateral arterio-venous fistula (two-stage protocol, Ligature-Shunt model), and unilateral arterio-venous fistula-creation alone (Solo-Shunt model).

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Recent studies have raised concerns about the safety of low frequency ultrasound in transcranial therapeutic application in cerebral ischemia. This study was designed to evaluate safety aspects and potential deleterious effects of low frequency, 60 kHz ultrasound in treatment of experimental middle cerebral artery occlusion (MCAO) in rats. Forty-five male Wistar rats were submitted to either temporary (90 min; groups I and II) or permanent MCAO (groups III and IV) using the suture technique.

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Object: In territorial stroke vasogenic edema formation leads to elevated intracranial pressure (ICP) and can cause herniation and death. Brain swelling further impairs collateral blood flow to the ischemic penumbra and causes mechanical damage to adjacent brain structures. In the present study the authors sought to quantify the impact of this space-occupying effect on ischemic lesion formation.

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Limb-girdle muscular dystrophy type 2A (LGMD2A) is caused by mutations in the calpain 3 (CAPN3) gene. The clinical diagnoses of these cases in Bulgaria are very complicated, no protein analysis on muscular biopsy is available in our country, and genetic tests are the only possibility to clarify the diagnoses in clinically ambiguous cases. We screened 48 unrelated Bulgarian cases with preliminary diagnoses of different types of muscular dystrophy for mutations in the CAPN3 gene.

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Objective: The purpose of this study was to prospectively assess the feasibility and quality of combined MRI examinations consisting of thoracic MRI for suspected pulmonary embolism (PE) and MR venography for deep vein thrombosis (DVT), to assess the diagnostic yield of a combined examination for detecting thromboembolism compared with each component alone, and to retrospectively assess the concordance of duplex sonography and MR venography.

Subjects And Methods: Two hundred twenty-one consecutive patients (119 men, 102 women; mean age, 51 years; range, 31-86 years) with suspected PE were examined using a multitechnique thoracic MRI protocol (real-time MRI using true fast imaging with steady-state precession [FISP], perfusion MRI, and MR angiography) followed by stepping-table MR venography.

Results: Two hundred twenty-one thoracic MRI examinations were performed.

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Background And Purpose: Ultrasound-accelerated thrombolysis is a promising approach toward acute stroke treatment. In previous in vitro studies, we demonstrated enhanced thrombus destruction induced by 20-kHz ultrasound. However, little is known about biological interactions of low-frequency ultrasound with brain tissue.

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