Objective: To study a method for verifying the doses to PTV and OAR as well as the 2D dose distribution arising from IMRT through using radiochromic films and TLDs. Methods: Totally 7 medical electronic linear accelerators from Varian, Siemens and Elekta were selected. The polystyrene phantom provided by IAEA was conducted with CT scan. After irradiation with 6 MV X-rays, the TLDs and films were returned to the secondary standard dosimetry laboratory of China CDC for measurement and estimation. Results: According to the IAEA requirements, the relative deviations between TLD-measured and TPS-planned values for PTV and OAR doses were both within ±7.0%. For PTV, the measured relative deviations for 5 accelerators were in the range of -4.0% to 3.4%, consistent with the IAEA requirements, whereas the values for the other 2 accelerators were in the range of -7.0% to 10.6%, not consistent with the requirements. For OAR, the values for 4 accelerators were in the range of -5.6% to 3.3%, consistent with the IAEA requirements, whereas the values for the other 3 accelerators were in the range of -20.8% to 11.5%, not meeting the requirements. As required by the IAEA, the 2D dose distribution 3 mm/3% pass rate should be higher than 90%. The measured values for 5 accelerators were in the range of 91.8% to 98.5%, consistent with the requirements, whereas the values measured for the other 2 were 45.0% and 77.0% respectively, not meeting the requirements. Conclusions It is feasible for using TLDs and radiochromic films to verify the doses to PTV and OAR and the 2D dose distribution in IMRT. This method should be applied to not only quality verification but also hospital internal audit to the extent possible.

Objective:To study the effect of the injected bone marrow mesenchymal stem cells (BMSC) on rats with pulmonary fibrosis induced by paraquat (PQ) during different poisoning periods and explore the potential mechanism.Methods:From October to December 2018, BMSCs of SPF SD rats were isolated and purified by whole-bone marrow adherent culture method and cultured to the Third Generation (P3) . The surface antigens CD29, CD90, CD45 and CD34 of P3 BMSC were detected by Flow cytometry, the formation of alkaline phosphatase (ALP) , calcium nodules and fat droplets were observed by ALP, Alizarin Red staining and oil red O staining. At the same time, 36 SPF male rats were randomly divided into 6 groups: NC Group (Blank Control Group, injected with the same amount of saline) and PQ group (PQ model group, injected with 20% PQ solution 18 mg/kg intraperitoneally) , bMSC-A group, BMSC-B group, BMSC-C group and BMSC-D group were injected with BMSC suspension 1×10 6 cells/mice at 3 h、3 d、7 d and 14 d after PQ poisoning. After 28 days, the rats were killed, the lung organ coefficients were calculated, the hydroxyproline (HYP) content in lung tissue was calculated by alkaline hydrolysis, and the lung injury and fibrosis were observed by HE and Masson staining, serum TGF-1、TNF-α、MMP-9 and TIMP-1 were detected by Elisa. Results:High Purity BMSCs were successfully isolated and obtained. The P3 BMSC generation was positive expression of CD29、CD90、and negative expression of CD34、CD45, and had the potential of osteogenic and adipogenic differentiation. The results of HE staining and Masson staining showed that the alveolar structure in NC group was intact and homogeneous, in PQ group, the alveolar structure was severely damaged and a lot of collagen fibers and fibroblasts were deposited, and the degrees of lung injury in each BMSC intervention group were obviously less than in PQ group, in BMSC-A group and BMSC-B group, the degrees of reduction were obvious. Compared with NC group, the Lung organ coefficient, HYP content in lung tissue and TGF-β1, TIMP-1 levels in serum were significantly higher in PQ group ( P<0.05) , while TNF-α and MMP-9 had no significant difference ( P>0.05) . Compared with PQ group, the lung organ Coefficients, HYP, TGF-1 and TIMP-β1 in BMSC-A and BMSC-B groups were lower than those in PQ group ( P<0.05) . The Lung organ coefficients, TGF-β1 and TIMP-1 in BMSC-C and BMSC-D groups were lower than those in PQ group, there was no significant difference ( P>0.05) . Conclusion:Early BMSC injecting can alleviate pulmonary fibrosis induced by PQ. The mechanism may be that BMSC can reduce pulmonary fibrosis through reducing the level of TGF-β1 and regulating the balance of TIMP-1/MMP-9, threrby reducing inflammatory damage and increasing the degradation of extracellular matrix (ECM) .

Objective:To study the effect of the injected bone marrow mesenchymal stem cells (BMSC) on rats with pulmonary fibrosis induced by paraquat (PQ) during different poisoning periods and explore the potential mechanism.Methods:From October to December 2018, BMSCs of SPF SD rats were isolated and purified by whole-bone marrow adherent culture method and cultured to the Third Generation (P3) . The surface antigens CD29, CD90, CD45 and CD34 of P3 BMSC were detected by Flow cytometry, the formation of alkaline phosphatase (ALP) , calcium nodules and fat droplets were observed by ALP, Alizarin Red staining and oil red O staining. At the same time, 36 SPF male rats were randomly divided into 6 groups: NC Group (Blank Control Group, injected with the same amount of saline) and PQ group (PQ model group, injected with 20% PQ solution 18 mg/kg intraperitoneally) , bMSC-A group, BMSC-B group, BMSC-C group and BMSC-D group were injected with BMSC suspension 1×10 6 cells/mice at 3 h、3 d、7 d and 14 d after PQ poisoning. After 28 days, the rats were killed, the lung organ coefficients were calculated, the hydroxyproline (HYP) content in lung tissue was calculated by alkaline hydrolysis, and the lung injury and fibrosis were observed by HE and Masson staining, serum TGF-1、TNF-α、MMP-9 and TIMP-1 were detected by Elisa. Results:High Purity BMSCs were successfully isolated and obtained. The P3 BMSC generation was positive expression of CD29、CD90、and negative expression of CD34、CD45, and had the potential of osteogenic and adipogenic differentiation. The results of HE staining and Masson staining showed that the alveolar structure in NC group was intact and homogeneous, in PQ group, the alveolar structure was severely damaged and a lot of collagen fibers and fibroblasts were deposited, and the degrees of lung injury in each BMSC intervention group were obviously less than in PQ group, in BMSC-A group and BMSC-B group, the degrees of reduction were obvious. Compared with NC group, the Lung organ coefficient, HYP content in lung tissue and TGF-β1, TIMP-1 levels in serum were significantly higher in PQ group ( P<0.05) , while TNF-α and MMP-9 had no significant difference ( P>0.05) . Compared with PQ group, the lung organ Coefficients, HYP, TGF-1 and TIMP-β1 in BMSC-A and BMSC-B groups were lower than those in PQ group ( P<0.05) . The Lung organ coefficients, TGF-β1 and TIMP-1 in BMSC-C and BMSC-D groups were lower than those in PQ group, there was no significant difference ( P>0.05) . Conclusion:Early BMSC injecting can alleviate pulmonary fibrosis induced by PQ. The mechanism may be that BMSC can reduce pulmonary fibrosis through reducing the level of TGF-β1 and regulating the balance of TIMP-1/MMP-9, threrby reducing inflammatory damage and increasing the degradation of extracellular matrix (ECM) .

OBJECTIVE: To observe the status of protein kinase B(Akt) signaling pathway in Akt phosphorylation induced by free silica(SiO_2) in mouse monocyte macrophage cell RAW264.7, and the role of Akt signaling pathway in early inflammatory response of silicosis. METHODS: i) RAW264.7 cells were routinely cultured and divided into SiO_2 stimulation groups at 5 different time points, and were stimulated for 15, 30, 60, 120 and 240 minutes with SiO_2 suspension with a final concentration of 100 mg/L, and a control group without SiO_2 treatment. At the end of treatment, the cells were collected and the expression of phospho-(Ser/Thr) Akt(p-Akt) was detected by Western blotting to select the optimal time of treatment. ii) RAW264.7 cells were divided into control group(no treatment), SiO_2 exposure group(previous concentration of 100 mg/L SiO_2 suspension) and intervention group(pre-treated with Akt activation inhibitor deguelin for one hour and then treated with 100 mg/L SiO_2 suspension), samples were collected after incubation for 60 minutes. The p-Akt expression and distribution in cells were detected by cellular immunofluorescence assay, the relative expression of p-Akt in cells was detected by Western blotting, and the levels of tumor necrosis factor-α(TNF-α) and transforming growth factor-β1(TGF-β1) in the supernatant of cells were detected by enzyme-linked immunosorbent assay. RESULTS: i) The optimal treatment time of RAW264.7 cells for SiO_2 exposure model was 60 minutes in vitro. ii) The results of cellular immunofluorescence assay showed that Akt phosphorylation was activated in RAW264.7 cells after stimulant with SiO_2, and the fluorescence of p-Akt was enhanced in the SiO_2 exposure group than the control group, and in the intervention group it was relatively weaker than the SiO_2 exposure group. The relative expression of p-Akt as well as the levels of TNF-α and TGF-β1 in the SiO_2 exposure group and the intervention group were higher than that in the control group(P<0.05), and the above three idexes in the intervention group were lower than the SiO_2 exposure group(P<0.05). CONCLUSION: Akt signaling pathway is involved in the process of SiO_2-induced macrophages phosphorylation, and participates in the early inflammatory response of silicosis.

OBJECTIVE: To explore the effect of wearing earphone to listen to music on the high-frequency noise-induced hearing loss(NIHL) in noise-exposure workers. METHODS: A total of 651 male noise-exposure workers in an automobile manufacturer were selected as study subjects by using judgment sampling method. The level of noise exposure in the individuals and the pure tone hearing threshold were tested. According to the frequency of wearing earphone to listen to music after work, the subjects were divided into low-, medium-and high-frequency earphone-using groups, with 60, 436 and 155 workers in each group, respectively. The effects of wearing earphone to listen to music combined with occupational noise exposure on high-frequency NIHL were analyzed. RESULTS: The high-frequency NIHL detection rate of the study subjects was 31.3%(204/651). The detection rate of high-frequency NIHL in these three groups from low to high was low-, medium-and high-frequency earphone-using groups(P<0.01). The detection rate of high-frequency NIHL in the high-frequency earphone-using group was higher than that of the low-and medium-frequency earphone-using groups(43.2% vs 25.0%, 43.2% vs 28.0%, P<0.01). Multivariate logistic regression analysis showed that wearing earphones to listen to music was a risk factor for high-frequency NIHL in noise-exposure workers(P<0.01) after eliminating the influence of confounding factors such as age, length and level of noise-exposure, and wearing anti-noise ear plugs. The higher frequency of wearing earphone to listen to music, the higher risk of high-frequency NIHL. CONCLUSION: Wearing earphone to listen to music after work and occupational noise exposure had a synergistic effect on high-frequency NIHL in noise-exposure workers.

Objective: To study the hearing status and analyze the related influencing factors in noise-exposed workers in an automobile manufacture enterprise, and put forward suggestions for prevention of noise-induced hearing loss. Methods: Noise exposure level testing, audiometry testing and questionnaires were performed for noise exposed workers in the automobile manufacture enterprise. To analyze the relationship between different factors and noise-induced hearing loss by cumulative noise exposure(CNE) calculated 8-hour continuous A-weighted equivalent noise level and seniority. Results: The detection rate of hearing loss in noise-exposed workers was 22.8%. The noise exposure intensity of stamping workshop is higher than other workshop, and the hearing loss detection rate of stamping workshop workers is higher than other workshop workers. The detection rate of hearing loss has significant difference in L_{Aeq·8 h}, seniority, CNE, age, high temperature and wearing earplugs (P<0.05). The results of logistic regression analysis showed that CNE, age and high-temperature were risk factors for noise-induced hearing loss (P<0.05 and OR>1) and there was an increasing tendency of hearing loss with increase in length of service and CNE, while using of earplugs was a protective factor (P<0.05 and OR<1). With the increase of CNE, the incidence of hearing loss is the rising trend. Conclusion It is suggested to strengthen the noise control and individual protection and improve the high-temperature working environment, which plays an important role in reducing the occurrence of noise-induced hearing loss.

Objective To evaluate the therapeutic effect of chemotherapeutic drugs on pancreatic carcinoma based on patient-derived xenograft(PDX)models,and to screen an individualized treatment strategy. Methods Fresh human pancreatic carcinoma tissues were subcutaneously transplanted into nude mice to establish PDX models which could be stab-ly passaged. The traceability of PDX models was determined by STR analysis. The PDX models were treated with three dif-ferent clinical chemotherapeutic drugs oxaliplatin, gemcitabine and irinotecan, respectively, and the tumor volumes were measured at different times. The therapeutic effect of those drugs was assessed by TGD mathematical model and plasma CA19-9 test. Results The traceability of patient-derived xenograft samples was up to 99.99%. Compared with the con-trol group,the treatment with irinotecan and gemcitabine inhibited tumor growth significantly(P=0.001), and gemcit-abine had even better result. The minimum toxic effect in the mice was induced by irinotecan treatment,followed by gem-citabine treatment. Conclusions Pancreatic carcinoma PDX models are successfully established and can be stably pas-saged. Gemcitabine shows the most inhibitory effect on tumor growth based on TGD mathematical model assessment, and deserves to be recommended as the preferred drug for individual treatment of pancreatic carcinoma.

The high-fidelity prostate tumor patient-derived xenograft ( PDX) model is the basis for studies of biology and pharmacotherapy of prostate cancer. However, the development and application of prostate tumor has been hampered by a low success rate of transplanted primary tumors in mice as most prostate cancers are highly relevant to hormones. The high-fidelity PDX model of prostate cancer better maintains the histopathology and molecular heterogeneity of the original tumor. Here, we review the improved method of establishing PDX model of prostate cancer, including the testosterone supplementation, the quality of the original tumor tissue as well as the stromal niche, and the application of commonly used therapeutic drugs, and to provide a theoretical basis for clinical studies of prostate tumor. These attempts are very important for development of new agents and research on mechanisms of prostate cancer. It will further promote the individualized treatment of prostate cancer.

The patient-derived orthotopic xenograft (PDOX) model better maintains the genetic characteristics of the primary tumor, and keep stable in histology, transcriptome, polymorphism and copy number variations. It also retains the interaction between the tumor mesenchyma, microvessels and stroma, and the tumor metastatic properties. Therefore, PDOX model can predict disease prognosis more accurately and can be used to screen appropriate individualized treatment strategies, thus, shows perfect prospect in clinical application. However, due to the differences between mouse and human microenvironment, morphological distinctions between orthotopic xenograft tumors and primary tumors still exist, and tumor metastasis can not be ensured by orthotopic xenograft. Thus, in order to construct the individualized PDOX model and to promote its clinical translation, it is necessary to analyze the histomorphology of orthotopic xenografts, to establish database of the transplantation model and share the information of the model. In this review, we will summarize the main features of PDOX models with its advantages and limitations, and looking forward to its application in the future.

OBJECTIVE: To explore the relationship between noise-induced hearing loss, hypertension and abnormal electrocardiogram(ECG) in noise-exposed workers. METHODS: A judgment sampling method was adopted to select 555 male workers with hearing loss as study group and 555 male workers with normal hearing as control group in the similar environment in an automobile manufacturing enterprise in Guangzhou. Pure tone audiometry,blood pressure measurement and ECG examination were performed in both groups to analyze the relationship between hearing loss and hypertension and abnormal ECG. RESULTS: The prevalence rate of hypertension and abnormal ECG was higher in the hearing loss group than the control group(P < 0. 05). The multiple logistic regression analysis showed that after adjusting confounding factors such as age,seniority,body mass index,drinking et al,the risk of hypertension in hearing loss group was higher than the control group(P < 0. 05) and the odds ratio(OR) was 2. 255 [95% confidence interval(CI) : 1. 093-4. 655 ],while adjusting the confounding factor of drinking,the risk of ECG abnormalities in hearing loss group was higher than the control group(P < 0. 05) and the OR was 1. 408(95% CI: 1. 027-1. 930). CONCLUSION: Workers exposed to noise with hearing loss increase the risk of hypertension and abnormal ECG.