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Fragestellung: Insbesondere chirurgische Abteilungen stehen im Ruf, überkommene hierarchische Strukturen zu pflegen. Es wird vermutet, dass eine steile Hierarchie das Risiko für medizinische Fehler erhöhen kann; Hierarchie und Arbeitsatmosphäre haben wesentlichen Anteil am Human [zum vollständigen Text gelangen Sie über die oben angegebene URL], Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2019)

Objectives: The differentiation of bone-resorbing osteoclasts depends on the level of intracellular calcium, which stimulates calcineurin to dephosphorylate and thereby facilitate the translocation of NFAT, the designated master transcription factor of osteoclastogenesis, to the nucleus. A range of [for full text, please go to the a.m. URL], Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2019)

Biomechanical research on tendon tissue evaluating new treatment strategies to frequently occurring clinical problems regarding tendon degeneration or trauma is of expanding scientific interest. In this context, storing tendon tissue deep-frozen is common practice to collect tissue and analyze it under equal conditions. The commonly used freezing medium, phosphate buffered saline, is known to damage cells and extracellular matrix in frozen state. Dimethyl sulfoxide, however, which is used for deep-frozen storage of cells in cell culture preserves cell vitality and reduces damage to the extracellular matrix during freezing. In our study, Achilles tendons of 26 male C57/Bl6 mice were randomized in five groups. Tendons were deep frozen in dimethyl sulfoxide or saline undergoing one or four freeze-thaw-cycles and compared to an unfrozen control group analyzing biomechanical properties, cell viability and collagenous structure. In electron microscopy, collagen fibrils of tendons frozen in saline appeared more irregular in shape, while dimethyl sulfoxide preserved the collagenous structure during freezing. In addition, treatment with dimethyl sulfoxide preserved cell viability visualized with an MTT-Assay, while tendons frozen in saline showed no remaining metabolic activity, indicating total destruction of cells during freezing. The biomechanical results revealed no differences between tendons frozen once in saline or dimethyl sulfoxide. However, tendons frozen four times in saline showed a significantly higher Young’s modulus over all strain rates compared to unfrozen tendons. In conclusion, dimethyl sulfoxide preserves the vitality of tendon resident cells and protects the collagenous superstructure during the freezing process resulting in maintained biomechanical properties of the tendon.

Fragestellung: Sehnengewebe besteht bis zu 90% aus Typ-I Kollagen, welches in Fibrillen und Faszikeln organisiert ist und durch Adhäsionsmoleküle der Extrazellulärmatrix (EZM) verbunden wird. Integrin alpha-2/beta-1 ist ein kollagenbindendes Protein mit hoher Affinität [zum vollständigen Text gelangen Sie über die oben angegebene URL], Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2017)

Made available in DSpace on 2018-08-02T00:02:59Z (GMT). No. of bitstreams: 1 tese_11316_RAFAEL STANGE.pdf: 18863643 bytes, checksum: 7eec06a241d800e3340182b1e220712c (MD5) Previous issue date: 2017-03-20 A medic¸ao de vazao ´e uma importante opera¸cao no escopo das aplica¸coes industriais, sendo regulamentado por diversos ´orgaos reguladores. Para satisfazer tais exigencias, a tecnologia por medi¸cao ultrassonica tem passado por grande evolu¸cao nos u´ltimos anos, muito em func¸ao de sua caracter´ıstica de baixa perda de carga associada, devido `a sua configura¸cao. Contudo, acidentes de linha causam interferencia em suas leituras, devido a altera¸coes no perfil de velocidades do escoamento. Novas pesquisas e modelos sao apresentados de forma a entender e considerar tais perturba¸coes, e adaptar as condi¸coes das instala¸coes industriais. De modo a agregar novos esfor¸cos, o presente trabalho apresenta uma aproxima¸cao do fator de perfil k atrav´es de t´ecnicas de problemas inversos. Essa abordagem busca quantificar as altera¸coes no perfil de velocidade e considerar tais efeitos no fator k. Neste trabalho foram abordadas simulac¸oes de escoamentos com Nu´mero de Reynolds entre 1⇥104 a2⇥106 sob influencia de curvas. Aproxima¸coes foram feitas com simula¸coes a 10D, 20D e 80D a` jusante da curva. Os resultados encontrados mostram-se promissores, sendo que, as diferen¸cas entre as simulac¸oes obtidas atrav´es da presente proposta para o fator k e os valores de vazao de referencia, ficaram abaixo de 2% na maioria dos casos simulados. Palavras-chave: Medidor de vazao ultrassonico, canal acu´stico, escoamentos turbulentos, problema inverso, Levemberg-Marquardt.

Rheology of living cells has developed an increasing need for high throughput measurements. Diseases such as cancer heavily remodel the cytoskeleton and impinge on cellular functions. Cells affected by such diseases show altered rheologic responses on many different levels rendering cells' mechanical fingerprints-a potential target for diagnostics. To counteract naturally occurring distributions of properties in samples of living cells and foster the validity of experiments, high numbers of single cell measurements are necessary. Here, we present the 'in flow optical stretcher' (IFOS), a concept of non-invasive optical cytometry capable of high throughput rates, while working in a regime of long measurement times and low frequencies. The setup deforms whole cells in a continuous flow by optical forces, bypassing steps of cell positioning that are unavoidable in state-of-the-art optical stretcher devices. A prototype was built using polydimethylsiloxane soft lithography. In a proof of premise experiment, we show that in the IFOS it is possible to deform cells of mammalian origin which have been treated with cytochalasin. All recorded successful experiments took place in less than 2 s each, as opposed to 10-20 s in state-of-the-art optical stretcher devices. Although other microfluidic rheology devices achieve significantly higher throughput rates, they operate in different frequency regimes and probe different mechanical responses. The IFOS still captures viscoelastic properties and active responses of cells while aiming to maximize the throughput at creep times on the order of seconds. It can be assumed that an automatic IFOS reaches a throughput an order of magnitude higher than current devices that are based on optical stretching for cell rheology.

Fragestellung: Integrine (ITGA) sind Zelladhäsionsrezeptoren, die eine Interaktion zwischen der Zelle und ihrer Mikroumgebung ermöglichen. Das ITGA a2b1 besitzt eine besonders hohe Bindungsaffinität gegenüber fibrillärem Kollagen Typ I (KOL I), das mit 95% Hauptbestandteil[zum vollständigen Text gelangen Sie über die oben angegebene URL], Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2016)