Objective To evaluate the effect and mechanism of rt-PA combined with high pressure oxygen (HPO)on cerebral ischemia-reperfusion injury in rats.Methods The model of cerebral ischemia-reperfusion injury was constructed by using middle cerebral artery occlusion.The neurological function score;brain index,water content and infarction volume;SOD;LDH;NOS;MDA;LD;NO and NOS were measured.The protein and mRNA expressions of iNOS,BDNF,p75NTR and TrkB were also detected by RT-PCR and Western blot to evaluate and compare the protective effect of rt-PA combined HPO therapy. Results rt-PA combined HPO could significantly decrease the neurological function score;brain index,water content,and infarction volume;SOD;NOS;MDA;LD;NO and NOS but increase LDH content and the weight of rats,compared with rt-PA.In addition,rt-PA combined HPO could increase BNDF and TrKB expressions and downregulate the expressions of iNOS and p75NTR,compared with rt-PA (P<0.05).Conclusion The rt-PA combined HPO therapy has a greater protective effect than rt-PA therapy and its mechanism might be related to having antioxidant effects, increasing the expressions of BDNF and TrKB,and decreasing the expressions of iNOS and p75NTR.

Objective To compare the differences of the spectral CT parameters between benign and malignant mediastina lymph nodes and to investigate the value of spectral imaging in the differential diagnosis. Methods According to the follow-up and pathology results, a total of 73 patients were enrolled in this study. One experienced radiologist determined the locations of lymph nodes on CT images corresponding to the surgical pathological ones. A total of 47 malignant nodes and 65 benign nodes were found. The longest and shortest diameters of lymph nodes in mediastina window were measured .The vHU, IC, WC, Zef and the CT values of normal lung, normal muscle and lymph nodes at 40, 70 and 140 keV were measured. The indices were compared between the benign nodes and malignant nodes by independent-samples t test. The Spectral HU curves were drawn. Results The long and short diameter of malignant lymph nodes were (28.8 ± 10.5),(20.3 ± 9.1)cm , while they were were (14.0 ± 4.6),(7.5 ± 1.8)cm for benign lymph nodes. Malignant nodes were significantly larger than benign nodes (t= 6.54, 7.13, respectively, P<0.05), The differences of the CT values at 40, 70 and 140 keV and the vHU, IC, WC, Zef for the normal lung, normal muscle and lymph nodes between the two groups had no statistical significance (P>0.05). The two groups showed similar spectral HU curve slopes (1.86 values 1.73). Conclusion Spectral imaging may not be helpful in the differential diagnosis of malignant and benign lymph nodes.