BACKGROUND:Disc functional magnetic resonance imaging studies are mostly carried out under lying and a non-load state, and do not reflect the changes in morphology and function of the upright human body under disc load conditions. Therefore, we need to study characteristics of disc functional magnetic resonance imaging in the upright state. OBJECTIVE: To analyze the effect of axial load on apparent diffusion coefficient and T2 of intervertebral discs. METHODS:The study consisted of 17 patients with low back pain aged 34-65 years. Before and after axial load, T2 weighted MR imaging, T1 weighted MR imaging, diffusion tensor imaging, and T2-mapping imaging of the lumbar spine were performed. Load quality was 40%-50% body weight. At 10 minutes after axial load, another diffusion tensor imaging was performed. After 15-minute load, another T2-mapping sequence was scanned. Diffusion tensor imaging scan parameters: single echo-planar imaging, repetition time 2 500 ms, echo time 89 ms, six diffusion directions, b value of 400 s/mm2, sweep time 4:10 minutes. Raw data of diffusion tensor imaging were used to construct apparent diffusion coefficient map and b0 map. Apparent diffusion coefficient value of intervertebral discs was calculated before and after loading. T2 map was automaticaly constructed using T2-mapping sequence to measure apparent diffusion coefficient and T2 values in the whole intervertebral disc of nucleus pulposus, and the changes of them were analyzed under short-time axial load. RESULTS AND CONCLUSION:Pfirrmann grading results in 17 patients with 85 discs were obtained as folows: 0 in Grade I, 26 in Grade II, 19 in Grade III, 30 in Grade IV, and 10 in Grade V. Al 85 disc T2 relaxation time mapping and 84 disc apparent diffusion coefficient mapping were accepted. Under short-time axial load in 84 discs, apparent diffusion coefficient reduced in the whole disc (reduced 38×10-3 mm2/s,Z=2.567,P < 0.05) and nucleus pulposus (reduced 62×10-3mm2/s,Z=3.461,P < 0.05). Apparent diffusion coefficient changes mainly affected Grade Pfirrmann III discs (reduced 55×10-3mm2/s,Z=2.556,P < 0.05). T2 changes mainly affected normal intervertebral discs (Pfirrmann grade II). Under the load, T2 value of intervertebral discs diminished (reduced 3.17 ms,Z=2.967,P < 0.05). No significant difference in apparent diffusion coefficient and T2 value was detected under the load in other grades of the intervertebral discs (P > 0.05). These results suggest that changes in apparent diffusion coefficient and T2 values were different due to different Pfirrmann grades under short-time axial load. To evaluate magnetic resonance imaging function of intervertebral discs, we should choose different evaluation method according to different degeneration degrees.

AIM:To investigate the role of mesenchymal stem cell-induced regulatory dendritic cells ( MSC-DCregs) in mouse acute graft-versus-host disease( aGVHD) model.METHODS: Bone marrow cells from BALB/c ( H-2 d ) mice were isolated and were induced to differentiate into DCs.The DCs were selected by flow cytometry, and after 10 d co-culture with MSCs, they were induced to be MSC-DCregs.Male 8-week-old C57BL/6 (H-2b) mice were used as do-nor mice.The female 8-week-old BALB/c (H-2d) mice, who had received 100 cm source-skin distance, 30 cm ×30 cm radiation field, 700 cGy total body irradiation (TBI) pretreatment were used as recipient mice.The recipients were divided into 5 groups:control group, TBI group ( injected with medium only) , bone marrow transplantation group ( injected with 1 ×107 bone marrow cells), aGVHD group (injected with 1 ×107 bone marrow cells and 1 ×107 spleen cells), and MSC-DCregs group (injected with 1 ×107 bone marrow cells, 1 ×107 spleen cells and 1 ×106 MSC-DCregs).The white blood cell count, recipients’ chimerism, clinical evaluation of aGVHD, survival analysis and pathological changes were deter-mined.RESULTS:Hematopoieic recovery was seen at 10 d after transplantation.The recipients’ chimerism was parallel to the donors’ at 30 d.The median survival time of the mice in aGVHD group and MSC-DCregs group was 27 d and 33 d, and the survival rates at 30 d were 20% and 100% (P<0.01), respectively.The clinical scores of the mice in MSC-DCregs group were lower than those in aGVHD group ( P<0.01) .Moreover, the pathological changes in the skin and liver of the mice in MSC-DCregs group were less serious than those in aGVHD group.CONCLUSION: The MSC-DCregs in-duce an aGVHD tolerance in vivo, and further research of its mechanism is still in great necessary.

AIM:To investigate the expression and potential role of complement 5a receptor (C5aR) in chro-nic graft-versus-host disease (cGVHD).METHODS:The expression of C5aR on lymphocytes and the frequency of CD4+CD25+ Foxp3+ regulatory T cells (Tregs) in 20 cGVHD patients and 9 healthy donors was detected by flow cytometry.The correlation between the expression of C5aR and the percentage of Tregs in the cGVHD patients was analyzed.In addition, the splenocytes from the mice were cultured in vitro, and stimulated these splenocytes with recombinant mouse C5a protein (rmC5a).The peripheral blood mononuclear cells (PBMCs) from cGVHD patients were cultured in vitro, which was inhibited by C5aR antagonist (C5aRA).The frequency of Tregs in these splenocytes and the PBMCs were evaluated by flow cytometry.RESULTS:The expression of C5aR on the lymphocytes was significantly increased in the cGVHD patients compared with the healthy donors, while the percentage of Tregs was markedly lower in the cGVHD patients.The expression of C5aR was negatively correlated with the percentage of Tregs.Furthermore, the development of Tregs was suppressed by rmC5a stimulation, but was promoted by C5aRA in vitro.CONCLUSION:C5aR elevation is associated with Treg reduction in cGVHD, indicating that C5aR may play a potential role in suppressing Tregs, resulting in the incidence of cGVHD.

Objective: To investigate the effects of artesunate treatment on chronic graft-versus-host disease (cGVHD). Methods: Recipient BALB/c mice received 8 × 10⁶ bone marrow cells with 8×10⁶ spleen cells from B10D2 mice. Artesunate solubilized in acetone was injected intraperitoneally every day at the dose of 1 mg/kg at Day 28 after BMT. The clinical scores, survival and histopathological damage were analyzed. The frequency of Th17 and Tregs in PB and spleens from the mice were evaluated by flow cytometry. In addition, CD4⁺ T cells from the spleens of mice were cultured in vitro, then stimulated with artesunate, the frequency of Th17 and Tregs in these splenocytes were evaluated by flow cytometry. Results: Artesunate administration diminished clinical and histopathological damage, and improved the survival of cGVHD mice[(46.57±7.83)% vs (55.71±6.99)%, χ²=5.457, P=0.020]; Artesunate contributed to Tregs development [(4.45±0.04)% vs (8.40±0.23)%, t=15.679, P<0.001; (6.62±0.24)% vs (10.48±0.48)%, t=6.587, P=0.003] while decreased Th17 cells [(1.51±0.18)% vs (0.58±0.19)%, t=7.233, P<0.001; (1.48±0.38)% vs (0.71±0.18)%, t=3.653, P=0.011] expressions in both PB and spleens, and decreased the Th17/Treg ratio (0.34±0.05 vs 0.09±0.03, t=7.621, P=0.002; 0.19±0.03 vs 0.06±0.02, t=6.993, P=0.002). Moreover, artesunate suppressed the Th17 cells expressions [(0.82±0.37) % vs (3.39±1.22) %, t=4.044, P=0.007] and contributed to Tregs development [(34.63±1.29) % vs (14.28±1.69) %, t=19.119, P<0.001], and also decreased the Th17/Treg ratio (0.24±0.09 vs 0.02±0.01, t=4.780, P=0.003) in vitro. Conclusions Artesunate suppressed the Th17 cells expressions and contributed to Tregs development, which provided new sights into the development of a novel drug for cGVHD, e.g., artemisinin.

OBJECTIVE: To observe the correct use of personal protective equipment( PPE) in migrant workers exposed to organic solvent,and to analyze the influencing factors. METHODS: A total of 108 migrant workers engaged in organic solvents working in the small and medium-sized enterprises were selected as study subjects by judgment sampling method.A self-designed questionnaire was used to investigate their PPE utilization status. In addition,the influcing factors on the effective usage of PPE were analyzed. RESULTS: There were 52. 8% of migrant workers exposed to organic solvent who use the PPE correctly in their work. The multiple logistic regression analysis showed that the higher the average monthly income,the greater the possibility of using the PPE correctly( P < 0. 05). The more frequent the number of respiratory tract infections in the past 6 months,the less likely the PPE was used correctly( P < 0. 05). The co-workers or supervisor often urge the use of PPE and co-workers use PPE correctly when exposed to organic solvent play a role in promoting the right usage of PPE in migrant workers( P < 0. 05). CONCLUSION: The correct use of PPE in migrant workers exposed to organic solvent is still needed to be improved. The peer education and improvement of enterprises' occupational health management are considered as important measures to promote the proper use of PPE in migrant workers exposed to organic solvent.

Objective: To monitor the WT1 mRNA level and its dynamic changes in patients with myelodysplastic syndromes (MDS) after hypomethylating agents (HMA) , as well as to assess the significance of WT1 mRNA levels and its dynamic changes in evaluating the efficacy of HMA and distinguishing the disease status of heterogeneous patients with stable disease (SD) . Methods: Bone marrow or peripheral blood samples of 56 patients with MDS who underwent hypomethylating agents (≥4 cycles) from November 2009 to March 2018 were tested by real-time quantitative polymerase chain reaction (PCR) to detect the expression of WT1 mRNA, and to observe the correlation between the dynamic changes of WT1 mRNA expression and clinical efficacy and prognosis of patients. Results: WT1 mRNA expression levels of MDS patients decreased significantly after 3 cycles of hypomethylating agent treatment. Besides, the WT1 mRNA expression levels of patients increased significantly after diseases progression. According to the dynamic changes of WT1 mRNA expression levels during SD, 45 cases could be further divided into increased group and non-increased group. In those SD patients with increased WT1 mRNA expression level, the ratio of suffering disease progression or transformation to AML was 95.65% (22/23) , whereas the ratio turned to be 9.09% (2/22) for the non-increased group (χ²=33.852, P<0.001) . Compared with those SD patients reporting no increase in WT1 mRNA expression level, the overall survival[17 (95%CI 11-23) months vs not reached, P<0.001] and progression-free survival [13 (95%CI 8-18) months vs not reached, P<0.001] of those SD patients reporting increase in WT1 mRNA expression level were significantly shorter. Conclusion WT1 mRNA expression level is a useful indicator to assess the efficacy of hypomethylating agents in MDS patients. Especially in patients with SD, detection of the changes in WT1 mRNA expression level is able to predict disease progression and help to make clinical decision.