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81.
Temporal expression of PTHrP during endochondral bone formation in mouse and intramembranous bone formation in an in vivo rabbit model 总被引:1,自引:0,他引:1
V Kartsogiannis J Moseley B McKelvie ST Chou DK Hards KW Ng TJ Martin H Zhou 《Canadian Metallurgical Quarterly》1997,21(5):385-392
Expression of parathyroid hormone-related protein (PTHrP) messenger RNA (mRNA) and protein was investigated throughout the developmental progression of endochondral bone formation in mouse and intramembranous bone formation in an in vivo model in rabbit, using in situ hybridization and immunohistochemistry. Endochondral bone formation was investigated in a developing embryo, newborn, and adult mouse. In fetal long bones through to newborn (day 7), PTHrP mRNA and protein were consistently expressed in chondrocytes within the proliferative, transitional, and hypertrophic zones. In addition, high levels of PTHrP were also detected in osteoblasts on the surface of trabecular bone surfaces. Similarly, at the adult stage (week 7), PTHrP mRNA and protein were consistently expressed in chondrocytes at epiphyseal ends of the subarticular cartilage, within cortical periosteum, as well as in osteoblasts located at the metaphyseal trabecular bone surfaces. Using an in vivo intramembranous bone formation model in rabbits, expression of PTHrP mRNA and protein was demonstrated in preosteoblasts prior to trabecular bone formation (1-week bone harvest). As bone formed (2-, 3-, and 4-week bone tissue harvests), PTHrP mRNA and protein were highly expressed in actively synthesizing osteoblasts and in those osteocytes embedded within the superficial layers of the bone matrix. Lining osteoblasts and osteocytes buried deeply in the bone matrix displayed weak or no signal for PTHrP. The pattern of spatial and temporal expression of PTHrP demonstrated in cartilage cells and osteoblasts in the two systems suggests an important role of PTHrP in both endochondral and intramembranous bone formation. 相似文献
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MS Binding Assays are a label‐free alternative to radioligand binding assays. They provide basically the same capabilities as the latter, but an unlabeled reporter ligand is used instead of a radioligand. The study presented herein describes the development of MS Binding Assays that address D1 and D5 dopamine receptors. A highly sensitive, rapid and robust LC–ESI‐MS/MS quantification method for the selective D1 dopamine receptor antagonist SCH23390 ((5R)‐8‐chloro‐3‐methyl‐5‐phenyl‐1,2,4,5‐tetrahydro‐3‐benzazepin‐7‐ol) was established and validated, using its 8‐bromo analogue SKF83566 as an internal standard. This quantification method proved to be suitable for the characterization of SCH23390 binding to human D1 and D5 receptors. Following the concept of MS Binding Assays, saturation experiments for D1 and D5 receptors were performed, as well as competition experiments for D1 receptors. The results obtained are in good agreement with results from radioligand binding assays and therefore indicate that the established MS Binding Assays addressing D1 and D5 receptors are well‐suited substitutes for radioligand binding assays, the technique that has so far dominated affinity determinations toward these targets. 相似文献
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Matthias Wanner Katarzyna Krawczyk Daniela Schäfer Thadeus Schauer 《Progress in Organic Coatings》2010
Multi-layer coating systems are the state of the art for painting of metal and plastic surfaces e.g. in the automotive industry. Utilizing such systems consisting of several specialized coating materials, a high adhesion and a good corrosion protection can be reached, along with good barrier properties, chemical and scratch resistance as well as appealing surface appearance. The interphase regions between single layers of such systems represent areas of a potential weakness, where a delamination and a premature coating degradation can start. To test in a short time the protective properties of the coating, a special hydrothermal cyclic loading test procedure was developed, which causes accelerated build-up of internal stress within the coating system. Using an electrochemical impedance spectroscopy with various optimized electrode geometries, it was possible to detect the early stages of coating degradation and to compare different coating systems. Internal stress measurements contributed additionally to a better understanding of the coating degradation. 相似文献
87.
Zhonghua Li S. Schmauder A. Wanner 《Metallurgical and Materials Transactions A》2000,31(11):2943-2948
Finite element modeling based on axisymmetrical cells was performed for relating the Bauschinger effect (BE) in metal matrix
composites (MMCs) to the reinforcement volume fraction and shape, matrix hardening behavior, and plastic prestrain levels.
It was found that elastic inclusions in MMCs introduce a significant BE, which is ascribed to the residual phase stresses
in the component phases. The BE introduced by cylindrical inclusions is more significant than that of spherical ones and increases
rapidly with increasing the aspect ratio of the cylindrical inclusion. The volume fraction of the elastic inclusion has a
strong effect on BE. The hardening behavior of the matrix has a weak effect on BE. The BE increases with increasing plastic
prestrain level. 相似文献
88.
Normal gait requires the dynamic integration of central and peripheral nervous systems acting on an intact musculoskeletal framework. A number of specific disease processes, as well as aging, may compromise this interaction. Despite the complexity of human gait, most common gait disorders can be identified by the experienced clinician, using the fundamental tools of history and physical examination. 相似文献
89.
The role of ensheathing cells, a macroglial cell type with a unique presence in the olfactory system, in the outgrowth of olfactory receptor cell neurites was explored in vitro. Glial cell cultures harvested from both the olfactory bulb nerve layer and the hippocampus were established and immunocytochemically characterized. The expression of the p75 low-affinity nerve growth factor receptor by ensheathing cells was used to distinguish them from other macroglial subpopulations. Results indicated that ensheathing cell cultures were approximately 80% pure. Olfactory receptor cells were cocultured with ensheathing or hippocampal glial cells or were seeded on laminin or poly-L-lysine as controls. Olfactory receptor cells extended the longest primary neurites when cocultured with ensheathing cells. Neurite extension on hippocampal glia and laminin was less extensive than that observed on ensheathing cells but higher than that on poly-L-lysine. The neurite outgrowth-promoting effect of ensheathing cells was, at least in part, mediated by diffusible factors, because olfactory receptor cell neurite extension could also be facilitated when receptor cells were cultured in ensheathing cell-conditioned media. In contrast, cortical neurons extended neurites of equivalent lengths on ensheathing and hippocampal glia. The results suggest that ensheathing cells may release factors that support the continuous outgrowth of olfactory receptor cell axons and, therefore, the capacity of this pathway to recover from injury. 相似文献
90.