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991.
992.
Dimitrios Daoussis Anastasia Kanellou Elias Panagiotopoulos Dionysios Papachristou 《International journal of molecular sciences》2022,23(12)
Dickkopf-1 (Dkk-1) is a key regulator of bone remodeling in spondyloarthropathies. Nevertheless, data regarding its expression in cells of pathophysiologic relevance, such as mesenchymal stem cells (MSCs), are lacking. Herein, we aimed to address DKK1 gene expression and Wnt pathway activation in MSCs from patients with ankylosing spondylitis (AS) and explore the effect of IL-17 on MSCs with respect to DKK-1 expression and Wnt pathway activation. Primary MSCs were isolated from the bone marrow of the femoral head of two patients with AS and two healthy controls undergoing orthopedic surgery. MSCs were cultured for 7 days in expansion medium and for 21 days in osteogenic medium in the presence or absence of IL-17A. Gene expression of DKK-1 and osteoblastic markers was determined by RT-PCR. Alkaline phosphatase activity, alizarin red and Van Kossa staining were used to assess osteoblastic function and mineralization capacity. DKK-1 was significantly downregulated in MSCs and osteoblasts from patients with AS compared to controls. Moreover, MSCs and osteoblasts from AS patients displayed increased Wnt pathway activation and enhanced osteoblastic activity, as indicated by increased expression of osteoblast marker genes and alkaline phosphatase activity. IL-17 downregulated DKK-1 expression and increased osteoblastic activity and mineralization capacity. DKK-1 is underexpressed in MSCs from AS patients compared to controls, whereas IL-17 has an inhibitory effect on DKK-1 expression and stimulates osteoblastic function. These data may have pathogenetic and clinical implications in AS. 相似文献
993.
994.
Ling Xiong Long Wang Ting Zhang Xinyuan Ye Feihong Huang Qianqian Huang Xinwu Huang Jianming Wu Jing Zeng 《International journal of molecular sciences》2022,23(14)
Radiation-induced thrombocytopenia is a common and life-threatening side effect of ionizing radiation (IR) therapy. However, the underlying pathological mechanisms remain unclear. In the present study, irradiation was demonstrated to significantly reduce platelet levels, inhibit megakaryocyte differentiation, and promote the apoptosis of bone marrow (BM) cells. A metabolomics approach and a UHPLC-QTOF MS system were subsequently employed for the comprehensive analysis of serum metabolic profiles of normal and irradiated mice. A total of 66 metabolites were significantly altered, of which 56 were up-regulated and 10 were down-regulated in irradiated mice compared to normal mice on day 11 after irradiation. Pathway analysis revealed that disorders in glycerophospholipid metabolism, nicotinate and nicotinamide metabolism, sphingolipid metabolism, inositol phosphate metabolism, and tryptophan metabolism were involved in radiation-induced thrombocytopenia. In addition, three important differential metabolites, namely L-tryptophan, LysoPC (17:0), and D-sphinganine, which were up-regulated in irradiated mice, significantly induced the apoptosis of K562 cells. L-tryptophan inhibited megakaryocyte differentiation of K562 cells. Finally, serum metabolomics was performed on day 30 (i.e., when the platelet levels in irradiated mice recovered to normal levels). The contents of L-tryptophan, LysoPC (17:0), and D-sphinganine in normal and irradiated mice did not significantly differ on day 30 after irradiation. In conclusion, radiation can cause metabolic disorders, which are highly correlated with the apoptosis of hematopoietic cells and inhibition of megakaryocyte differentiation, ultimately resulting in thrombocytopenia. Further, the metabolites, L-tryptophan, LysoPC (17:0), and D-sphinganine can serve as biomarkers for radiation-induced thrombocytopenia. 相似文献
995.
主要研究1Cr17Ni2不锈钢作为螺栓在具体工作环境中失效原因的分析和讨论,由于1Cr17Ni2钢的力学性能对合金成分、杂质含量和热加工工艺非常敏感,特别是回火温度对组织和性能影响明显,因此为获得良好的综合性能需要精确控制该钢的冶炼工艺及热加工工艺,同时对失效行为进行处理。 相似文献
996.
997.
前期研究发现天然雌激素E2可以弱化一种常见雌激素类污染物双酚A的活性,为探讨这一现象的机制,利用人体乳腺癌细胞MCF7,从细胞周期、雌激素受体途径、MAPKs信号途径进行实验.结果表明:E2可诱导DNA合成期细胞显著增高,抑制受体蛋白表达,提高ERK蛋白的表达,进而激活多种转录因子;双酚A显著抑制受体蛋白表达,对MAPKs信号通路基本没有影响,可同时提高DNA分裂期与间歇期细胞比例;两者联合后活化了受体途径和ERK途径,促进Cfos的转录表达,激活cyclin D1蛋白,增加S期及G2期细胞比例.E2弱化双酚A的可能机制为Cmyc蛋白表达下降. 相似文献
998.
Sm2Fe17Nx稀土永磁体 总被引:1,自引:1,他引:1
综述了Sm2Fe17Nx稀土永磁体合成与制备的主要方法如:传统粉末法、还原/扩散法、快淬法、机械合金化法、HDDR法以及橡皮模等静压技术等。介绍了Sm2Fe17Nx稀土永磁体的研究成果及最新研究进展。 相似文献
999.
LI Ping CAI Qi-zhou WEI Bo-kang ZHANG Xian-zhong 《钢铁研究学报(英文版)》2006,13(5):73-78
The effect of aging temperature on erosion corrosion (E-C) behavior of 17-4PH stainless steels in dilute sulphuric acid slurry containing solid particles was studied by using self-made rotating E-C apparatus. The effect of impact velocity on EC behavior of 17 4PH steels at different aging temperatures was analyzed. Surface micrographs of the specimens after E C test were observed by using scanning electron microscope (SEM). The results showed that under the condition of the same solution heat treatment, when aging temperature ranged from 400 ℃ to 610℃, the hardness reached the highest value near the temperature 460℃. The characteristics of E-C for 17-4PH stainless steels at different aging temperatures were as follows: pure erosion (wear) was dominant, corrosion was subordinate and at the same time corrosion promoted erosion. The effect of aging temperature on E-C rate of 17-4PH steels was not significant at low impact velocity, but it was found that E-C resistance of 17-4PH steels aged near 460℃ was the most excellent due to the best precipitation strengthening effect of fine and dispersed e-Cu phase. With a prerequisite of appropriate corrosion resistance, the precipitation hardening could significantly improve the E-C resistance of the materials. 相似文献
1000.
介绍V.17调制解调算法的原理,给出V.17在Blackfin532+uClinux平台上的软件实现,并针对Blackfin平台提出相应的优化方案.该方案主要针对Blackfin处理器的定点特性、分层的存储器架构、支持并行指令等特性进行了优化.优化后的调制解调器减少了对系统资源的占用量,而且性能也提升了约3倍.目前已应用到语音网关的传真Modem中. 相似文献