Boris Michael Holzapfel

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Synovial hemangioma is a rare benign intra-articular tumor. It may be a cause of pain and recurrent joint swelling in children and young adults. This report presents a 29-year-old patient with a synovial hemangioma in the left knee joint. Magnetic resonance imaging (MRI) showed the typical features of a soft tissue hemangioma and revealed a cystic invasion(More)
Over the last 4 decades innovations in biomaterials and medical technology have had a sustainable impact on the development of biopolymers, titanium/stainless steel and ceramics utilized in medical devices and implants. This progress was primarily driven by issues of biocompatibility and demands for enhanced mechanical performance of permanent and(More)
Modern cancer research requires physiological, three-dimensional (3-D) cell culture platforms, wherein the physical and chemical characteristics of the extracellular matrix (ECM) can be modified. In this study, gelatine methacrylamide (GelMA)-based hydrogels were characterized and established as in vitro and in vivo spheroid-based models for ovarian cancer,(More)
An NADPH oxidase complex composed of a membrane-bound flavocytochrome b558 consisting of two subunits (p22phox and gp91phox) and cytosolic activating factors (p47phox and p67phox) generates superoxide anions from oxygen in the respiratory burst of phagocytic cells. Inconsistent results have been previously obtained concerning its additional occurrence in(More)
Oxygen sensing was investigated in rat pheochromocytoma PC12 cells. They respond to hypoxia with an increased intracellular generation of reactive oxygen species (ROS), measured by oxidation of dihydrorhodamine 123. This increase is abolished by intracellular superoxide scavenging by Mn(III)-tetrakis(1-methyl-4-pyridyl)-porphyrin, and reduced or absent in(More)
BACKGROUND AND STUDY AIMS The majority of colonoscopies in Germany are performed under conscious sedation. Previous studies reported that pediatric colonoscopes reduce the demand for sedative drugs and may improve cecal intubation. The aim of this study was to compare a new ultrathin and a standard colonoscope in terms of propofol demand during colonoscopy.(More)
STUDY DESIGN Case report and review of the literature. OBJECTIVE We report a case of Grisel's syndrome with a delayed diagnosis. The patient's first presentation in our pediatric orthopedics department was 2 month after surgery (cochlea implantation) with a persistent torticollis. Radiographs revealed a subluxated atlantoaxial joint. We treated our(More)
Desmoid tumours of the extremity have a high recurrence rate. The purpose of this study was to analyse the outcome after resection of these tumours with special emphasis on recurrent disease and adjuvant therapeutic strategies. In this retrospective study we evaluated prognostic factors for recurrence-free survival after surgical treatment of desmoid(More)
Currently used xenograft models for prostate cancer bone metastasis lack the adequate tissue composition necessary to study the interactions between human prostate cancer cells and the human bone microenvironment. We introduce a tissue engineering approach to explore the interactions between human tumor cells and a humanized bone microenvironment.(More)
Despite positive testing in animal studies, more than 80% of novel drug candidates fail to proof their efficacy when tested in humans. This is primarily due to the use of preclinical models that are not able to recapitulate the physiological or pathological processes in humans. Hence, one of the key challenges in the field of translational medicine is to(More)