Objective To observe the effect of different concentrations of parathyroid hormone 1-34 on the adipogenic potential of rat bone marrow mesenchymal stem cells (BMSCs).Methods ① Rat bone marrow mesenchymal cells were separated and expanded by adherent culture.The morphology of cells was observed and cell surface markers were examined by flow cytometry.② The multi-lineage differentiation capability of cells was examined by culturing cells under conditions favorable for adipogenic and osteogenic differentiation.③ Taken P3 of BMSCs for test,different concentrations of PTH1-34 (0,10-10,10-9,10-8 mol/L) were used to stimulate BMSCs respectively,14 days later,lipoprotein lipase (LPL) activity were measured by enzyme linked immuno-sorbent assay (ELISA),mRNA expression of alkaline phosphatase (ALP) and PPARγ-2 were measured by realiime polymerase chain reaction (PCR).④ Statistical analysis:data were presented as x±s.All statistical analysis was performed with windows Statistical Praduct and Serice Solutions (SPSS) 13.0.One-way analysis of variance (ANOVA) was applied to determine the difference between groups.Least signisicant difference (LSD) was used to determine the difference between the two randomized groups.Differences were considered significant at a value of P＜0.05.Results The cells expressed CD44,CD29 but without expression of CD45.By culturing in adipogenic medium for 3 weeks and in osteogenic medium for 4 weeks respectively,and then identified by oil red O and Alizarin red,the cells were successfully induced to adipocytes and osteogenesis.Expressions of LPL were 11.20±0.16,7.62±0.48,5.84±0.57,5.32±0.52,mRNA expressions of PPARγ-2 were 2.80±0.05,1.36±0.23,0.94-±0.11,0.78±0.04,ALP activity were 0.191 ±0.016,0.333±0.024,0.549±0.025,0.684±0.021 respectively.Compared with the control group,different concentrations of PTH1-34 groups could decrease mRNA expression of LPL and PPARγ-2.ALP activity were increased(P＜0.05).Conclusion PTH1-34 inhibits BMSCs of adipogenic differentiation and promotes osteogenic differentiation in a dose-dependent manner.

Objective To figure out the optimal parameters of a volumetric modulated arc therapy ( VMAT) plan for cervical and upper esophageal cancer by quality evaluation of VMAT plans with different parameters, and to provide a reference for the design of clinical VMAT treatment plan. Methods Ten patients with cervical esophageal cancer and ten patients with upper esophageal cancer were enrolled as subjects. The Nucletron Oncentra 4. 3 treatment planning system was used to generate plans for Elekta Synergy VMAT accelerator. Six VMAT plans were made with variation in the gantry angle ( 2°, 3°, and 4°), the maximum delivery time (80 s, 110 s, and 150 s), and the collimator angle (0° and 45°). The doses to the planning target volume and organs at risk were analyzed by paired t test. Results For cervical and upper esophageal cancer, the quality of VMAT plans with a collimator angle of 45° was better than those with a collimator angle of 0°(P=0. 003?0. 007). For cervical esophageal cancer, there was no significant difference in quality between VMAT plans with a maximum delivery time of 110 s or 150 s and those with a maximum delivery time of 80 s ( P>0. 05 );for upper esophageal cancer, there was also no significant difference in quality between VMAT plans with three different maximum delivery times ( P>0. 05 ) . For cervical esophageal cancer, the VMAT plans with a gantry angle of 3° had a better quality than those with a gantry angle of 2° or 4°(P=0. 010?0. 048). For upper esophageal cancer, the VMAT plans with a gantry angle of 3° had a better quality than those with a gantry angle of 4° ( P=0. 010?0. 048) . Compared with those with a gantry angle of 2° , the VMAT plans with a gantry angle of 3° had a slightly better dose distribution in the target volume ( P=0. 046 ) , but a slightly higher dose to lung tissue ( V25 and V30 , P=0. 007 and 0. 026) . Conclusions The optimal initial parameters of a VMAT plan for cervical and upper esophageal cancer are a collimator angle of 45°, a maximum delivery time of 80 s, and a gantry angle of 3°.

Objective To investigate the application of the Monte Carlo dose calculation of output factors for electron beams in radiotherapy.Methods The code EGS4/MCTP was used to simulate the head of a medical linear accelerator (Varian 23EX) to calculate the output factors for 6 MeV,9 MeV and 18 MeV electron beams.The source-to-surface distance used was 100 cm.The field sizes ranged from 2 cm × 2 cm to 25 cm × 25 cm.The calculated output factors agreed with the corresponding measured factors which were measured by the IBA Phantom system to within 2％.Then,the output factors of direct articles and indirect articles which were under different energy and various cone-insert combinations were calculated by the code EGS4/MCTP.Results The calculated output factors agreement with the measurements is found to be mostly under the 1％ level.The variation of output factors depends on the characteristics of the beams and the modifications that the various cone-insert combinations introduce to these characteristics.Conclusions Monte Carlo dose calculations for electron beams in homogeneous water phantoms have been demonstrated to be accurate under the 1％ level in comparison with measurements.The output factors were influenced by energy and cone-insert combinations in complex ways.

Objective:To investigate the factors influencing phytohemagglutinin (PHA) response in the detection of Mycobacterium tuberculosis infection by gamma interferon release assay (IGRA). Methods:A retrospective case-control study was conducted on 360 hospitalized patients who received IGRA in West China Hospital of Sichuan University from January 2019 to December 2021. According to PHA response (IFN-γ level), they were divided into three groups: negative mitogen response group (IFN-γ<2 pg/ml), weak positive mitogen response group (IFN-γ: 2-100 pg/ml), and normal mitogen response group (IFN-γ>400 pg/ml).Results:Immune diseases were independently associated with negative (OR=0.34, 95%CI: 0.17-0.72, P=0.004) and weak positive mitogen responses (OR=0.29, 95%CI: 0.16-0.55, P<0.001). Infections caused by pathogens other than Mycobacterium tuberculosis was independently associated with negative mitogen response (OR=0.266, 95%CI: 0.09-0.83, P=0.023), while immunodeficiency was independently associated with weak positive mitogen response (OR=0.280, 95%CI: 0.12-0.63, P=0.002). Mitogen response was significantly correlated with the levels of albumin and hemoglobin in serum and the counts of neutrophils and lymphocytes ( P<0.001). Conclusions:Immune diseases and immunodeficiency can affect mitogen response. Therefore, clinicians should give attention to mitogen response in the interpretation of IGRA test results to prevent misdiagnosis and underdiagnosis. Besides, to a certain extent, mitogen response can reflect the infection status of hospitalized patients.