Objective To investigate the dose-response of micronuclei (MN) frequency in the lymphocytes irradiated with or without combination of α-particles and γ-rays. Methods Human lymphoblast cells HMy2.CIR were irradiated with 0 - 1 Gy of α-particles,0 - 5 Gy of γ-rays,and 0.025 -0.5 Gy of α-particles followed by different doses of γ-rays,respectively.The micronuclei (MN) in the irradiated cells were measured with the cytokinesis block technique,and the dose-responses of MN were established under different irradiation conditions.Results For γ-ray irradiation,the dose-response of MN was well-fit by the linear-quadratic model with an equation Y =c + αD + βD2.For α-particle irradiation,the MN induction increased linearly with the dose less than 0.250 Gy. But when the dose of α-particles increased continually,the dose-response curve bended and could be well fit with the BaD model Y =c + αD + σ[ 1 - exp( - δD) ] exp( - βD) where radiation-induced bystander effect (RIBE) was indicated.For the combined exposure,the dose-response of MN was similar to that of γ-irradiation when the dose of α-particles was lower than 0.1 Gy,but it was similar to that of α-irradiation when the dose of α-particles was higher.When the dose of α-particles was 0.2 and 0.5 Gy,MN induced by the mixed radiation were significantly higher than the sum of corresponding irradiation alone ( t =5.22 - 11.86,P ＜ 0.05 ).Conclusions The radiation damage of α-particles differs from that of γ-rays,where RIBE may be involved.The combination irradiation of α-particles and γ-rays has a synergistic effect on radiation damage of lymphoblast cells.

Objective To investigate the CT features and different risk CT findings of intestinal stromal tumor. Methods The CT imaging data of 25 cases of intestinal stromal tumor confirmed by pathology and compared with operative and pathologic findings were retrospectively studied. Analyzing the CT features based on Histopathologieal classification of the different risk groups and using chi-square test to compare the differences. Results There were 9 cases which tumors originated from the jejunum, and 13 cases from ileum, only 3 cases from duodenum. Among them, 2 cases were submucosal type, 13 cases were intramural type, and 10 cases were subserous type. The pathologic patterns of different risk which included high-risk, intermediated-risk, low-risk, and very low-risk were 12 cases, 7 cases, 5 cases and 1 cases respectively. A typical CT manifestations of intestinal stromal tumors were a outward growth of irregular or round soft tissue mass originated in small intestine which had clear boundary and the non-homogeneous density, which corresponding to necrosis, cystic change, mucoid degeneration and sinus or cavity. Mesenteric fat invaded by tumor showed high-density lines or points shape. The Enhancement of lesion was obvious and not homogeneous which showed little change in peak of enhancement between arterial phase and venous phase. Intestinal stromal tumors took 5 cm as the boundary which including different size, shape, density, and appearance vessel-like artery shadow at arterial phase between different risk groups(low, very low-risk group and intermediated, high-risk group) were statistically different (P ＜0.05), while enhanced degree without significant difference (P ＞ 0.05). Conclusion CT findings of small intestine stromal tumor have characteristics and CT features have significant difference between different risk groups. These features of more than 5 cm in diameter, non-homogeneous density, irregular shape and chaos appearance like vascular enhancement are showed in intermediated-high-risk group.

Objective To construct a risk prediction model by integrating the molecular subtypes of pan-creatic ductal adenocarcinoma(PDAC)and immune-related genes.Methods With GSE71729 data set(n=145)as the training set,the differentially expressed genes and differential immune-related genes between the squamous and non-squamous subtypes of PDAC were integrated to construct a regulatory network,on the basis of which five immune marker genes regulating the squamous subtype were screened out.An integrated immune score(IIS)model was constructed based on patient survival information and immune marker genes to predict the clinical prog-nosis of PDAC patients,and its predictive performance was tested with 5 validation sets(n=758).Results PDAC patients were assigned into high risk and low risk groups according to the IIS.In both training and validation sets,the overall survival of patients in the high risk group was shorter than that in the low risk group(both P＜0.001).The multivariable Cox regression showed that IIS was an independent prognostic factor for PDAC(HR=2.16,95％CI=1.50-3.10,P＜0.001).Conclusion IIS can be used for risk stratification of PDAC patients and may become a potential prognostic marker for PDAC.