Objective To explore a new way to improve the repairing effect of tendon allograft by pretreatment with ethyldimethylaminopropyl carbodiimide (EDC) cross-linking. Methods Rabbits' tendon allografts were obtained by lyopyilization.The allografts were then cross-linked and heparinized by EDC and N-hydroxy-succinimide (NHS) respectively.The degradation rate,cytotoxicity and histocompatibility of the cross-linked allografts were detected and compared with those of untreated at different time points.The injured anterior cruciate ligaments (ACL) were repaired by tendon allografts with and without cross-linking pretreatment in rabbits.The tendon-bone healing was observed and compared by light microscopy and scanning electron microscopy (SEM) at 1,3,6 months. Results The degradation rate of the pretreated tendon allografts [(6.26 ± 3.16)％] was significantly lower than that of the unpretreated [(30.70 ± 10.24)％]( t = 14.200,P = 0.025 ).The pretreated tendon allografts were atoxigenic and produced significantly lower inflammatory reaction ( P ＜ 0.05 ).The pretreated tendon allografts also showed more powerful capability of repairing ACL injury and shorter time of tendon-bone healing. Conclusion Tendon allografts cross-linked and heparinized by EDC/NHS may promote tendon-bone healing with improved stability,degradation and biocompatibility.

Objective To summarize our experience in microsurgical treatment of dumbbell tumors. Methods The clinical features,surgical approaches,operative techniques and surgical results of 21 cases of dumbbell tumors were analyzed retrospectively.Four surgical approaches were adopted according to the size and location of tumors,including,posterior midline approach(in 7 cases),modified far lateral approach(in 5 cases),posterior midline supplied by anterior cervical approach(in 2 cases)and paramidline approach(in 7 cases). Results In this series,10 cases of tumors were situated in the cervical,6 in thoracic,4 in lumbar and 1 in sacral segment of the spine.Total removal were achieved in 95% (20/21),and subtotal removal in 5%(1/21).Postoperative pathological diagnosis revealed 15 neurinomas,5 spinal meningiomas and 1 metastatic adenocarcinoma.14 cases of meningiomas and 1 metastatic adenocarcinoma were followed up for 1 to 48 months.11 of the 14 patients recovered completely,with 3 of them living daily life independently,4 maintainly radical hypoesthesia,and one having decubital ulcer unhealed.No postoperative malformation and dysfunction of the disposed spine occurred in these patients.Magnetic resonance imaging scans in 11 of the 14 follow-up cases revealed no tumor recurrence,of which inhanced MRI scans were performed in 8 cases. Conclusions dumbbell tumors should be treated by one-stage operation.Microsurgical technique could improve the rate of total removal,and decrease postoperative complications.

Objective To study the dose distribution characteristics formobile intra-operative radiotherapy accelerator (Mobetron) in an operating room,and to provide basic data for developing appropriate radiation protection measures and protection standard.Methods For most commonly used electron energy 9 MeV,TLD dosimeters were placed at 50,100,150 and 200 cm high plane,respectively.For each plane,the measurement points were selected at every 50 cm from the central axis at every 45° at eight different directions.Also different electron energies,such as 4,6,9 and 12 MeV,were taken into consideration at the plane at 100 cm height.After 10 Gy with a dose rate of 10 Gy/min were delivered,the TLD dosimeters were used to read out the data.Results For 9 MeV,at the phantom plane(100 cm high plane),the average doses were 169,756,395 and 241 μSv at 50,100,150 and 200 cm from the central axis,respectively.Themaximum deviation between the doses at 50 cm from the central axis in different angles and their average values were 9.1％.In the identical angle,the average doses of 50,100,150 and 200 cm high planes at the distance of 100 cm from central axis were 527,756,570 and 141 μSv,respecitvely.For the energies of 4,6,9 and 12 MeV,the average doses were 573,486,689 and 781 μSv at 100 cm from the central axis at 90° of 100 cm high plane.Conclusions For the same energy,the dose values at different directions were decreased by the minus exponential function law with the distance.The doses were uniformly distributed at different directions at the same distance from the central axis.The doses on the plane of 100 cm height were much higher than those at other heights,and the dose values were increased with the election energy.

Objective:To investigate mechanisms underlying the signal crosstalk of VEGF-IL-6-STAT3 between cutaneous melanoma cells and vascular endothelial cells.Methods:EC-304 vascular endothelial cells were divided into 3 groups: control group cultured in conventional endothelial cell-conditioned medium, vascular endothelial growth factor (VEGF) group cultured in endothelial cell-conditioned medium containing 50 μg/L VEGF 165, A375 co-culture group co-cultured with a melanoma cell line A375. After 24-, 48- and 72-hour treatment, the culture medium was collected, and enzyme-linked immunosorbent assay was performed to detect the level of interleukin-6 (IL-6) . Cultured A375 cells were divided into 4 groups: control group receiving conventional culture in Dulbecco′s modified Eagle′s medium (DMEM) , A375+ EC-304 group co-cultured with EC-304 cells, A375+ EC-304+ IL-6 group co-cultured with EC-304 cells in DMEM containing 50 μg/L IL-6 (an agonist of the signal transducer and activator of transcription-3 [STAT3] pathway) , A375+ EC-304+ JSI-124 group co-cultured with EC-304 cells in DMEM containing 1 μmol/L JSI-124 (a STAT3 pathway inhibitor) . After 24-, 48- and 72-hour treatment, cells were collected, and Western blot analysis, cell counting kit-8 (CCK8) assay and Transwell invasion assay were performed to determine the protein expression of STAT3 and phosphorylated (p) -STAT3, cellular proliferative activity and invasive activity, respectively. Two-way analysis of variance and t test were used for statistical analysis. Results:The level of IL-6 significantly increased in the culture medium of EC-304 cells in the VEGF group and A375 co-culture group compared with the control group ( FVEGF = 29.63, P < 0.001; FA375 = 11.09, P = 0.020) . Compared with the control group, the A375+ EC-304 group showed significantly enhanced protein expression of p-STAT3 in A375 cells ( P < 0.001) , increased cell activity ( P < 0.001) , and increased number of invasive cells (152.66 ± 16.04 vs. 86.13 ± 7.24, t= 4.43, P < 0.001) ; compared with the A375+ EC-304 group, the A375+ EC-304+ IL-6 group showed significantly increased protein expression of p-STAT3 ( P < 0.001) , enhanced cell activity ( P < 0.001) , and increased number of invasive cells (187.34 ± 14.38, t= 2.17, P < 0.001) ; compared with the A375+ EC-304 group, the A375+ EC-304+ JSI-124 group showed significantly decreased protein expression of p-STAT3 ( P < 0.001) , decreased cell activity ( P < 0.001) , and decreased number of invasive cells (124.92 ± 8.72, t=-1.86, P < 0.001) . Conclusion:There is a signal crosstalk of VEGF-IL-6-STAT3 between cutaneous melanoma cells and vascular endothelial cells, which may play an important role in the proliferation and invasion of A375 cells.

Objective To study the calculation of the room shielding thickness of tomotherapy accelerator,a new type of radiotherapy facility,especially the impact of the beam block on the shielding design.Methods According to the relevant standards,combined with the room geometry,the shielding thickness was calculated without the presence of the beam block,considering the primary beam,the scattered beam and leakage.Meanwhile,the shielding thickness was also calculated as comparison with the presence of the beam block,based on the characteristics of tomotherapy facility and its radiation field.Results There was statistical difference between the shielding thicknesses calculated with the presence of the beam block and those without the beam block,to the primary beam direction including the south wall,north wall,the roof and the floor,the shielding thickness were decreased by 95.59%,63.63% ,80.73%and 51.30% ,respectively.Conclusions For the tomotherapy accelerator,the beam block could be of great help to minify the shielding thickness of the room.The radiation field of the tomotherapy facility could be used for the calculation to improve accuracy,and the shielding thickness can also be estimated by subtracting the initial shielding thickness without beam block of the beam block equivalent thickness in the primary beam direction alternatively.

Objective To provide evidence for a more reasonable method of determining red bone marrow dose by analyzing and comparing existing simulation methods.Methods By utilizing Monte Carlo simulation software MCNPX,the absorbed doses of red hone marrow of Rensselaer Polytechnic Institute (RPI)adult female voxel phantom were calculated throush 4 different methods:direct energy deposition.dose response function(DRF),King-Spiers factor method and mass-energy absorption coefficient (MEAC).The radiation sources were defined as infinite plate.sources with the energy ranging from 20 keV to 10 MeV.and 23 sources with different energies were simulated in total.The source was placed right next to the front of the RPI model to achieve a homogeneous anteroposterior radiation scenario.The results of different simulated photon energy sources through different methods were compared.Results When the photon energy was lower than 100 key,the direct energy deposition method gave the highest result while the MEAC and King-Spiers factor methods showed more reasonable results.When the photon energy was higher than 150 keV taking into account of the higher absorption ability of red bone marrow at highcr photon energy,the result of the King-Spiers factor method was larger than those of other methods.Conclusions The King-Spiers factor method might be the most reasonable method to estimate the red bone marrow dose from external radiation.

Objective To study the role and mechanism of orexin A in cell viability of Alzheimer's disease (AD) cell model PC12. Methods PC12 cells were treated with 0, 10, 20, 30, 40 and 50 μmol/L Aβ25-35 for 24 h, and then, cell viability was measured by MTT to confirm which concentration was the suitable one to establish the AD cell models. (1) AD cell models were treated with 0, 0.01, 0.1, 1 and 2μmol/L orexin A for 24 h, and then, 30μmol/L Aβ25-35 was added for 24 h; MTT assay was used to determine the cell viability to conform the suitable concentration of orexin A. (2) Inverted phase contrast microscope was employed to observe the morphology changes of PC12 cells from the control group, 30 μmol/L Aβ25-35 treatment group, and 0.01 μmol/L orexin A+30 μmol/L Aβ25-35 treatment group. (3) The PC12 cells were given pretreatment of orexin A receptor inhibitor SB408124 for 2 h, and cell viability was detected. Results (1) Aβ25-35 at concentration 30μmol/L was the suitable one to establish the AD cell models;after being pretreated with different concentrations of orexin A, the cell viability showed significant differences (F=27.120, P=0.000), and 0.01μmol/L orexin A was the suitable concentration. (2) Some of the cells from the 30μmol/L Aβ25-35 treatment group had breaking-off of protuberance and damaged soma;cells from 0.01μmol/L orexin A+30μmol/L Aβ25-35 treatment group had breaking-off of protuberance, and the degree of damaged soma was eased as compared with that in the 30μmol/L Aβ25-35 treatment group. (3) If the cell viability of the control group was 100％, cell viability of orexin A receptor inhibitor group was 109.10％±0.36％, which was significantly decreased as compared with that in the 0.01 μmol/L orexin A pretreated group (117.24％±2.72％, P<0.05). Conclusion Orexin A can improve the cell viability via combination of its specific receptor; orexin A and its specific receptor may be new targets for prevention and cure of AD.