Kinase domain insert containing receptor promoter controlled suicide gene system selectively kills human umbilical vein endothelial cells

AIM： To study the selective killing of human umbilical vein endothelial cells （HUVECs） by a double suicide gene under the regulation of a kinase domain insert containing receptor （KDR） promoter and mediated by an adenoviral gene vector. METHODS： Human KDR promoter was cloned by polymerase chain reaction （PCR）, and two recombinant adenoviral plasmids pAdKDR-CdgIyTK, pAdCMV-CDglyTK were constructed according to a two-step transformation protocol. These two newly constructed plasmids were then transfected into 293 packaging cells to grow adenovirus, which were further multiplied and purified. HUVECs and LoVo cells were infected with either of the two resultant recombinant adenoviruses （AdKDR-CDglyTK and AdCMV-CDglyTK） respectively, and the infection rates were estimated by detection of green fluorescent protein （GFP） expression. Infected cells were cultured in culture media containing different concentrations of 5-fiuoroo/tosine （5-FC） and ganciclovir （GCV）, and the killing effects were measured. RESULTS： The two recombinant adenoviral plasmids pAdKDR-CdglyTK, pAdCMV-CDglyTK were successfully constructed and transfected into 293 cells. The resultant recombinant adenoviruses infected cells caused similar infection rates; and the infected cells exhibited different sensitivity to the prodrugs： HUVECs infected with AdCMV-CDglyTK and LoVo cells infected with AdCMVo CDglyTK were highly sensitive to the prodrugs, and HUVECs infected with AdKDR-CDglyTK were similarly sensitive but significantly more sensitive than the LoVo cells infected with AdKDR-CdglyTK （P 〈 0.001）. CONCLUSION： Selective killing of HUVECs may be achieved by gene transfer of double suicide gene under the regulation of the KDR promoter. This finding may provide an optional way to target gene therapy of malignant tumors by abrogation of tumor blood vessels.

Operative vs nonoperative treatment of displaced intraarticular calcaneal fracture: A meta-analysis of randomized controlled trials

AIM： To investigate clinical efficacy of displaced intra-articular calcaneal fracture （DIACF） following operation and nonoperation. METHODS： Literature search was performed of PubMed and Cochrane Library by two independent authors to identify randomized controlled trials （RCTs） comparing operative vs nonoperative treatment of DIACF from inception to December 31st, 2013. RCT quality was evaluated by the modified Jadad scale. Dichotomous variables were pooled using risk ratios by review manager 5.3 software. Fixed-effects or random-effects models were adopted with P 〉 0.05 or P ≤ 0.05 for heterogeneity tests, respectively.RESULTS： Eight RCTs comprising 767 cases met inclusion criteria. Results revealed that more surgically treated patients could resume pre-injury job （P = 0.006）. No statistical differences were found between the two groups in residual pain （P = 0.33）, shoe fitting problems （P = 0.07）, limited walking distance （P = 0.56） or secondary late arthrodesis （P = 0.38）. However, operative treatment was associated with a higher complication rate （P = 0.003）. Subgroup analyses of specific complications revealed that except for a higher risk of superficial wound problems （P 〈 0.0001） in operative group, the two groups had similar complication rate in deep wound infection （ P = 0.34）,CONCLUSION： Current evidence demonstrates that compared with operative treatment, conservative treatment of DIACF lead to similar clinical outcomes regarding residual pain, shoe fitting, walking distance and secondary subtalar arthrodesis but a significantly lower complication rate.