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Tribology of hydrogels for articular cartilage replacement
Křížová, Michaela ; Ranuša, Matúš (referee) ; Vrbka, Martin (advisor)
The bachelor's thesis deals with the description of the tribological properties of focal joint implants in the place of a cartilage defect. The application of focal implants is aimed at a group of younger patients who have to undergo surgery to repair damaged cartilage, but a total replacement is not suitable for them due to its lifetime. The contact of the focal implant and the opposite cartilage was simulated using metal samples and hydrogel, which has very similar properties to natural cartilage. For a possible comparison of values, a tribological measurement of the cartilage samples against the hydrogel was carried out. This pair serves as a model for defining friction in a healthy joint. The main task of this thesis was to determine the coefficient of friction of Ti6Al4V, Ti6Al4V+DLC, CoCrMo and cartilage against the hydrogel. The experiments were carried out using a tribometer in a pin-on-plate configuration. The Ti6Al4V alloy without coating and with DLC coating came out with the lowest coefficient of friction for both variants, almost identically 0.0526. Higher friction was measured for CoCrMo, but it differed from the titanium alloy to one-hundredth. On the contrary, the highest coefficient of friction was unexpectedly manifested in the cartilage samples, where the lowest friction was assumed. The error was due to poor selection of cartilage samples. The thesis simply describes the tribological behaviour of focal implants and the result is a material with the lowest coefficient of friction. The measurements performed could help further research into the issue of focal implants.
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Proteomic analysis of engineered hyaline cartilage
Kaňovská, Zuzana ; Vičarová,, Petra (referee) ; doc. RNDr. Irena Koutná, Ph.D (advisor)
The aim of this thesis was to observe the expansion of chondrocytes, specialized cartilage cells, in vitro in culture medium containing platelet rich plasma, to evaluate the effect of the addition of growth factors TGF-1 and IGF-1 to the medium and to explore the possibility of proteomic analysis application in the development of cartilage joint replacements. Chondrocytes were isolated form articular hyaline cartilage samples acquired in collaboration with the FN Brno and expanded in media. The resulting constructs were subsequently analyzed by immunocytochemical method, flow cytometry and proteomic analysis using LC-MS/MS.
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Developmental origin of cartilage skull elements in axolotl
Kloučková, Lenka ; Černý, Robert (advisor) ; Roček, Zbyněk (referee)
Despite the fact that some aspects of single studies differ, there's a generally accepted view that the whole cartilaginous viscerocranium of vertebrates is neural crest derived. By the series of isotopic transplantation experiments of presumptive neural crest on the model organism Ambystoma mexicanum I partly specify this oppinion and prove that the most ventro-caudal cartilage, the second basibranchial, is of a different origin. Furher I mention the level of the presumptive neural crest where the single parts of cartilaginous viscerocranium arise from. Moreover there is one element, the first basibranchial, which has double origin. I discuss also some other neural crest derivatives such as head and outer gills mesenchyme, the trabeculae cranii, part of the cartilaginous otic capsule or the connective tissue in the head. I have performed 179 transplantations between transgenic and normal axolotl embryos. My final analysis is composed of 65 embryos of stage 40 - 42 and 7 larvae of lenght of 15 - 17 mm.
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Morfogeneze orálního skeletu mihule ve vztahu k evoluci čelistí
Romášek, Marek ; Černý, Robert (advisor) ; Jandzík, Dávid (referee)
4 Neural crest-derived cellular cartilage is one of the defining characteristics of vertebrates. Elaboration of this tissue and its patterning allowed the evolution of jaws in the gnathostome lineage. Together these hallmarks helped jawed vertebrates become one of the dominant taxons in the animal kingdom. Lampreys, as basal jawless vertebrates, lie at a unique phylogenetic position that makes them ideal organisms for the study of evolution of vertebrate/gnathostome novelties. Larval lampreys possess a special oral skeleton composed of a tissue related to cartilage, termed mucocartilage. Despite considerable attention that has been paid to the evolutionary significance of mucocartilage, it is not yet clear, how this unique feature arises in development and to what extent it is homologous to gnathostome jaws. In this study, the development of oro-pharyngeal region was analyzed in the sea lamprey Petromyzon marinus. SEM imaging revealed shaping and topographic relationships of embryonic tissues, detailed plastic histology coupled with expression analyses of several molecular markers were used to describe origin, histogenesis and morphogenesis of mucocartilage. Furthermore, genetic regulation of the tissue was investigated in order to identify its unique or shared features. Mucocartilage is seen to...
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The Effect of Synovial Fluid Constituents on Friction and Lubrication of Articular Cartilage
Čípek, Pavel ; Dr. Prashant K. Sharma (referee) ; Muňoz, Anna Neus Igual (referee) ; Vrbka, Martin (advisor)
Práce se zabývá problematikou biotribologie modelu synoviálního kloubu. Cílem práce je popsat vliv složek synoviální kapaliny na formování mazacího filmu v modelu synoviálního kloubu. Práce je zaměřena na experimentální analýzu součinitele smykového tření a jeho propojení s pozorováním adsorbovaného mazacího filmu v kontaktu pomocí fluorescenční mikroskopie. Součástí práce je návrh tribometru, který umožňuje vizualizaci v průběhu experimentů. Tribometr je vyroben, kalibrován a verifikován pomocí komerčního tribometru. Dále je součástí práce návrh metodiky experimentů včetně návrhu postupu pro zpracování a hodnocení výsledků. Pro zpracování záznamu z vizualizace kontaktu byl navržen speciální software, který pracuje na principu segmentace obrazu. Poslední část práce je zaměřena na aplikaci vyvinuté metodologie spolu s nově navrženým tribometrem, což umožňuje posoudit roli složek modelové kapaliny u formování mazacího filmu v modelu synoviálního kloubu. Experimentální část je založena na měření tření za současné vizualizace kontaktu. Tato práce prezentuje originální výsledky rozšiřující oblast biotribologie synoviálního kloubu, které mohou pomoci dalšímu rozvoji účinné léčby pacientů s nemocnými klouby.
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Comparative analyses of cranial skeletogenesis and odontogenesis in basal Ray-finned fishes
Pospíšilová, Anna ; Černý, Robert (advisor) ; Přikryl, Tomáš (referee) ; Buchtová, Marcela (referee)
Skeletal (cartilaginous, bony, and dental) tissues undoubtedly exemplify the key innovation of vertebrates. Among all recent vertebrates, the most numerous and successful lineage is represented by the Ray-finned fishes that, accordingly, exhibit amazing variety of skeletal architectures and phenotypic adaptations. In order to depict fundamental principles of fish cranial skeletogenesis the developmental formation of skeletal architectures was described, compared and analyzed using members of early branching fish lineages, that exemplify very different strategies of skeletogenesis. While the Senegal bichirs and the Tropical gars are heavily armored forms with massive exoskeleton and hyperossified dental structures covering the whole oropharyngeal region, the European sterlets, on the contrary, possess mostly cartilaginous skeleton and reduce their dental structures during early development. Whole analysis is underpinned by the Northen pike, teleostean species with lightened skeletal architecture with comparable number of cranial elements. The present study represents the first complex comparative analysis of their skeletogenesis and odontogenesis. This allowed to define developmental strategies founding different lineage-specific skeletal architecture of vertebrates. Comparative description of...
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Design of Simulator for Friction Analysis in a Knee Joint
Dobrovolná, Lucie ; Studený, Zbyněk (referee) ; Sedlák, Josef (advisor)
This bachelor thesis deals with the construction of a device simulating the kinematics of the knee joint. Boundary conditions are inspired by the ISO 14243-3 standard and are based on the selection of suitable components. The simulator will be able to record the course of the coefficient of friction between the cartilage forming the translational motion, the CoCr head forming the rotational motion and the pressing force, thus helping to better understand the biotribological processes between the selected surfaces. The design must be developed with respect to the relative movement of components, sample material and lubrication. The introductory part of the text deals with an overview of current knowledge, which serves as the main input to the creation of the structure. Based on the research part, several conceptual solutions are created in the field of construction and method of friction measurement. The resulting solution is selected from the proposed concepts, which meets predetermined conditions and contains specific drives and sensors.
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Segmentation Of Cartilage Tissue In Micro Ct Images Of Mouse Embryos With Modified U-Net Convolutional Neural Network
Matula, Jan
Manual segmentation of cartilage tissue in micro CT images of mouse embryos is a very time-consuming process and significantly increases the time required for the research of mammal facial structure development. It is possible to solve this problem by using a fully-automatic segmentation algorithm. In this paper, a fully-automatic segmentation method is proposed using a convolutional neural network trained on manually segmented data. The architecture of the proposed convolutional network is based on the U-Net architecture with its encoding part substituted for the encoding part of the VGG16 classification convolutional neural network pre-trained on the ImageNet database of labelled images. The proposed network achieves average Dice coefficient 0.88 in comparison to manually segmented images.
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Automatic smoothing 3D models of cranial embryonic mouse cartilage
Kočendová, Kateřina ; Harabiš, Vratislav (referee) ; Jakubíček, Roman (advisor)
The focus of this thesis is the smoothing of manually segmented 3D models of mouse embryo craniofacial cartilege. During the process of manual segmentation, artefacts and other imperfections appear in the final models and need to be repaired. Firstly, manual segmentation is corrected using gradients and thresholding. Subsequent smoothing methods are constructed based on theoretical research. Algorithmizing is executed in the MATLAB environment. All the designed algorithms are then tested on selected models. Statistical evaluation is determined using the Srensen–Dice coefficient, where manually smoothened models cleared of all artefacts are used as the gold standard.
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Friction measuring of human joints
Šnejdar, Radim ; Ranuša, Matúš (referee) ; Čípek, Pavel (advisor)
This bachelor thesis concerns about the tribology of real joints. The aim of this work is an elucidation of the influence of chosen operating conditions on shear force coefficient. It deals especially about speed, strain and rehydration. The experimental tasks will be realized on tribometer, which is available in laboratories of ÚK. In this work, current state of knowledge in the area of discussed issues are described. Also the device and measured methods which help to measure and evaluate data files. In the last section of this work, the results are evaluated and the following conclusions are established.
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