Diabetes mellitus accelerates the progression of osteoarthritis in streptozotocin-induced diabetic mice by deteriorating bone microarchitecture, bone mineral composition, and bone strength of subchondral bone.

BACKGROUND: The purpose of this study was to develop an optimal diabetes-osteoarthritis (DM-OA) mouse model to validate that diabetes aggravates osteoarthritis (OA) and to evaluate the microarchitecture, chemical composition, and biomechanical properties of subchondral bone (SB) as a consequence of the DM-OA-induced damage induced. METHODS: Mice were randomly divided into three groups: DM-OA group, OA group, and sham group. Blood glucose levels, body weight, and food intake of all animals were recorded. Serum calcium (Ca) and osteocalcin (OCN) levels were compared in the three groups. The messenger ribonucleic acid (mRNA) and protein expression of key regulators for bone metabolism were detected. A semi-quantitative grading system [Osteoarthritis Research Society International (OARSI)] was used to evaluate cartilage and SB degeneration. Microspectroscopy, microindentations, micro-computed tomography (CT) imaging, and fracture load of compression testing were also used to evaluate trabecular SB properties. RESULTS: Glycemic monitoring and pancreas pathological results indicated stable high blood glucose and massive destruction of pancreas and islet cells in the DM-OA group. Serum levels of bone specific alkaline phosphatase (ALP-B) and tartrate-resistant acid phosphatase 5b (TRACP-5b) in the DM-group were higher than those of the other two groups while levels of serum Ca and OCN were lower. Meanwhile, the protein and mRNA expression of osteoblast-specific biomarkers [osteoprotegerin/receptor activator of nuclear factor kappa-B ligand (OPG/RANKL) ratio, collagen type I (COL-I), Runt-related transcription factor 2 (RUNX-2), OCN] were suppressed, and osteoclast-specific biomarkers [sclerostin (SOST)] was elevated in the DM-OA group. The mineral-to-collagen ratio, microindentation elastic modulus, hardness, micro-architectural parameters, bone mineral density, and fracture load of SB trabecular bone of the DM-OA group joint were lower than those of the other two groups. On the other hand, The OARSI score, trabecular spacing, and structural model index of the DM-OA group joint were higher than those of the other two groups. CONCLUSIONS: The glycemic and pancreatic pathological results indicated that the DM-OA model was a simple and reliable model induced by streptozotocin (STZ) and surgery. The results revealed the mechanisms through which diabetes accelerates OA; that is, by damaging and deteriorating the functions of SB, including its microarchitecture, chemical composition, and biomechanical properties.

[Segregation bands analysis of steel sample using laser-induced breakdown spectroscopy].

In the present paper, under optimum experimental condition, two middle-low alloy slab and homogeneous samples were analyzed under the condition of spatial resolution about 100 microm by scanning mode. Element 2D intensity distribution can be converted into 2D concentration distribution via establishing calibration curve. The results showed that there is a central segregation for C, Si, Mn, P, S and Cu for 86 # slab sample, and C, Si, P and Ti for 174 # slab sample, the width of segregation band was estimated, and it agrees well with metallographic analysis. Homogeneous sample was analyzed by scanning mode, the result showed that C, Si, Mn, P, S and so on are well distributed, and there is no segregation band existing. 2D distribution of element intensity or concentration can be used to indirectly reflect sample's homogeneity. Compared with traditional metallographic analysis, LIBS can not only show central segregation bands position and width, but also provide 2D concentration distribution for C, Si, Mn, P, S etc in detail. This method can be used to characterize segregation band position and its width rapidly, and provide theoretical guidance for improving metallurgical process.

[Quantity of released nickel ion from Ni-Cr alloy of compound galvano-ceramic bridge].

OBJECTIVE: To evaluate the biological safety of compound galvano-ceramic bridge by measuring the consistency of released nickel ion of the galvano-form slices cohered with Ni-Cr alloy slice specimens which were immersed in artificial saliva. METHODS: Specimens were divided into five groups with four tests and one control. Test specimens were made into the structure like rectangle sandwich that one side of Ni-Cr alloy was cohered to the center surface of galvano golden base of 0.2 mm and another side was fused porcelain with the thickness of 0.3 mm (group A), 0.5 mm (group B), 1.0 mm (group C), and 0.3 mm (group D). And the Ni-Cr alloys were totally embedded in galvano golden base and firing porcelain. Naked Ni-Cr alloy was taken as control. Group D was immersed into acid artificial saliva (AS) with high fluoride, while others were in acid AS at 37 degrees C for 120 h. Then the consistency of released nickel ion in the solution was measured with inductively coupled plasma-atomic emission spectrometry (ICP-AES). RESULTS: Nickel ions detected in the artificial saliva for the groups A, B, C, and D in acid AS with or without high fluoride were all under 0.005 mg/L Significant differences were found between each test group and the control [(0.65 +/- 0.45) mg/L]. CONCLUSIONS: Galvano-ceramic bridge, Ni-Cr alloy bridge with fused porcelain and golden base, shows biological safety responsible for the consistency of released nickel ion.