Objective]To measure and compare the MRI artifacts caused by common metal ic dental materials and common ceramic dental materials on different field-strength magnets.[Methods] A total of 3 common metal ic dental materials and 2 common ceramic dental materials were tested with 0.35T, 1.5T and 3.0T MR imagers. The artifact areas on these 3 different field-strength magnets were measured and statistical y compared. [Results]Zirconia in three field magnetic resonance(NMR) in T1 and T2 as no artifacts, casting porcelain, metal al oy, nickel chromium al oy and CoCr-al oy in three fields magnetic resonance(NMR) in T1 and T2 as al can produce different degree of artifacts, and artifacts area increased in turn. Cobalt chromium al oy and nickel chromium al oy measurements on the high side, the cobalt chromium al oy than other four kinds of materials on the high side( P<0.05),high nickel-chromium al oy was precious metal al oy, casting porcelain( P<0.05). [Conclusions]Commonly used metal ic dental materials could cause MR artifacts and image degradation. Compared with that on 0.35T, the artifact was increased on 1.5T magnet. Compared with that on 1.5T, the artifact was increased on 3.0T magnet.

BACKGROUND:Co-transplantation of bone marrow mesenchymal stem cells (BMSCs) and hematopoietic stem cells (HSCs) can improve the survival rate following radiation damage. OBJECTIVE:To review the mechanisms of BMSCs in hematopoietic reconstitution and immunomodulation after radiation damage. METHODS: Relevant articles included in the Web of science from 2005 to 2016 were retrieved, and the keywords were mesenchymal stem cells; radiation; radiation injury; hematopoietic stem cells; hematopoietic reconstitution; immunomodulatory in English. Then we sorted and analyzed the articles which were closely related to the theme. RESULTS AND CONCLUSION:BMSCs can repair broken DNA double bonds by autophagy and HR/NHEJ pathway; support and protect HSCs by intercellular interactions and paracrine action; and repair radiation-induced hematopoietic injury by inhibiting inflammation and immune responses to maintain HSC homeostasis. Therefore, BMSCs may function as an effective treatment for radiation-induced hematopoietic injury.

Objective To establish a method for isolation of cynomolgus monkey umbilical cord mesenchymal stem cells.Methods Fresh cynomolgus monkey umbilical cord was directly minced into pasty fine pieces, and the pieces were cultured in tissue flask with DMEM/F12 medium supplemented with 10% fetal bovine serum.The morphological characteristics of the resulting cells were examined, and their expression of mesenchymal cell surface markers were analyzed by flow cytometry.The multidifferentiation potential was examined in vitro, too.Results The fibroblast-like cells were successfully isolated from the fresh umbilical cord by an adherent culture procedure.These adherent cells expressed mesenchymal markers including CD29, CD44, and CD90, and also could be induced to differentiate into adipocytes, osteoblasts and chondrocytes.Conclusion Mesenchymal stem cells can be isolated from fresh cynomolgus monkey umbilical cord by using an adherent culture procedure.

BACKGROUND: Mesenchymal stem cells attract extensive attention because of good biological characteristics and broad prospects, but the cells gradually show the characteristics of the aging with the increase of individual age or incubation time in vitro. Nonhuman primates have similar biological characteristics with human being, and have unique advantage in the animal model and disease treatment research.OBJECTIVE: To analyze the difference in proliferation and differentiation of bone marrow mesenchymal stem cells from macaques at different ages and to explore the effect of age on bone marrow mesenchymal stem cells and the possible mechanism.METHODS: Bone marrow samples from male macaques aged < 3 years and over 20 years were collected through bone marrow puncture, and divided into young group and elder group, with three macaques in each group. Then, bone marrow mesenchymal stem cells were isolated and cultured in vitro, and the morphological changes, proliferation and differentiation ability were observed. Age-related beta-galactosidase staining was performed, and protein microarray and ELISA were used to detect cytokine levels.RESULTS AND CONCLUSION: With age, the proliferation and differentiation of bone marrow mesenchymal stem cells from the elder macaques were reduced significantly, and the number of senescent cells increased significantly; the levels of interleukin-1b, interleukin-4, interleukin-6, tumor necrosis factor α and vascular endothelial growth factor were elevated obviously, the levels of heparin-binding basic fibroblast growth factor and placental growth factor were reduced. These findings indicate that the body's aging lead to the reduction in the proliferation, differentiation and cytokine secretion of bone marrow mesenchymal stem cells.