Objective To introduce a finger leaf design that is applied to dual layer MLCs.Methods An optimization model was firstly constructed to describe the problem of determining leaf end shapes,and the corresponding problems were then solved by the simplex search method or the simulated annealing technique.Optimal parameters for arc shapes of leaf end projections were obtained,and a comparison was done between optimized MLCs and conventional MLCs in terms of field conformity.The optimization process was based on 634 target fields selected from the patient data base of a treatment planning system.Areas of these fields ranged from 20.0 to 602.7 cm with a mean and its standard deviation of (125.7 ±0.0) cm~2.Results The optimized leaf end shapes projected to the isocenter plane were semicircles.With the finger leaf design,the total area of discrepancy regions between MLC fields and target fields was reduced by 32.3% .Conclusions The finger leaf design improves the conformity of the MLC shaped fields to the desired target fields.

Tissue engineering has always been a hot spot in the life science area over the past few years. However, there are some problems, such as the multiplication of seeding cells, the preparation of tissue engineering scaffolds, and the controlled release of drugs from scaffolds and so on. Recently microspheres have been widely used to solve these problems. For example, microspheres are used as microcarriers to culture seeding cells. In addition, microsphers can be either used to prepare engineering scaffolds or directly used as scaffolds. Microspheres can be used to load drugs and control the drug release as well. In this paper the application of microspheres in tissue engineering is reviewed and the up-to-date methods are introduced, including ways of improving performances of microcarriers, preparing scaffolds with microspheres and adding drug-loaded microspheres into scaffolds.

The response of normal islet β cells to insulin resistance is compensatory insulin hypersecretion in order to maintain normoglycemia. The mechanisms involved in the compensation process including the expansion of β cell mass and enhanced β cell performance via various molecular cascades, signaling pathway sand their interactions have been extensively investigated in recent years.

The study on medical education directly affects the quality of education and cultivation of medical professionals as well as the level of running school.It is very important for the medical colleges to take some measures to solve these problems existing in medical teaching reform and research,such as renewing teachers' ideas,enhancing the standardization of management,increasing the enthusiasm of the teachers etc.

Objective To compare the relative accuracy of single-plane and biplane area-length methods for determining right ventricular (RV) volume and ejection fraction (RVEF) both in vitro and in vivo studies. Methods The in vitro study consisted of 15 human right ventricular casts and the in vivo study consisted of 45 patients. RV volume by single-plane area-length method was determined by the product of RV area from apical four-chamber view and the distance from RV apex to tricuspid annulus. RV volume by biplane area-length method was defined as 2/3?(the product of RV area from apical four-chamber view and the distance from pulmonary valve to tricuspid valve). The actual volume of RV casts was determined by water displacement method. RV angiography was used to determine RV volumes and RVEF in the in vivo study. Results RV volumes calculated from both single-plane and biplane methods correlated closely with RV cast volumes in the in vitro study (r= 0.87- and 0.91-, respectively; both P 0.05-), but RV volume determined by single-plane method significantly overestimated angiographic volume (P

Objective: To investigate the inhibitory effects of PTEN gene transfection combined with L-OHP on human cholangiocarcinoma cell line, QBC939, providing a new method for gene therapy of human biliary duct carcinoma. Methods: A eukaryotic expression vector containing PTEN gene was transfected into human QBC939 cells under mediation of lipofectamine and positive cell clones were selected and amplified. Expression of PTEN gene was detected by immunohistochemistry. MTT test was used to determine the in vitro activity of cells, electron microscope was applied to observe cell ultrastructure, and flow cytometry was used for determining the cell cycle and apoptosis. In vitro test was used to study the invasive ability of cells before and after treatment. Results: After transfected with PTEN gene, QBC939 cells had a higher expression of PTEN gene (P

Whether InfusaSleeve(IS) catheter can deliver antisense oligodeoxynucleotide (ODNs) following arterial denuation is unknown. We evaluate the feasibility of local endoluminal delivery of C-myc ODNs to the site of arterial denudation by using IS catheter and to determine the biological importance of these effects. IS catheter was introduced into right side of iliac artery of 21 rabbits after angioplasty of iliac artery. Animals were randomized to the control group (n＝6) receiving saline injection and the treated group receiving c-myc antisense (n＝15, 1 mg ODNs per vessel). In two weeks and 40 days following the operation, angiography was performed. Morphometric analyses were carried out in balloon-denuded iliac arteries. The expression of c-myc protein was detected by using a mouse monoclonal antibody to c-myc. Morphometric analyses carried out at 40 days after transcatheter c-myc antisense oligomer administration. The results showed that maximal neointimal area was reduced from 7.66±3.7(×105 μm2) in the control group (n＝6) to 4.04±1.02(×105 μm2) in the antisense treated group (n＝6, P＜0.05). These changes in vascular remodeling following denuding injury resulted in an increase in residual luman from 20～50% in the control group to 70～90% in the antisense-treated group. C-myc protein expression was virtually undetectable at baseline in locally ODNs-delivered arteries and detectable in control denuded arteries. The results show that: ①Single IS transcatheter administration allowed endoluminal delivery of ODNs to the site of arterial injury; ② c-myc antisense oligomer reduced the formation of neointime in denuded arteries, implying a therapeutic potential of this approach.

AIM: To investigate the possibility of 3T3 fibroblast growth on blood fibrin clot in culture medium with recombinant human basic fibroblast growth factor (rhbFGF). METHOD: Growth of the cells on blood fibrin clot was studied by phase-contrast, scanning and transmission electron microscopy and by Giemsa stain and MTT assay. RESULTS: The optimal concentration of rhbFGF for proliferation and survival of the cells was 100 ng/mL. The cells also grew on blood fibrin clot scaffold in the low-serum medium containing 100 ng/mL rhbFGF, and a greater number of the cells survived after 48 hours incubation compared to that after 24 hours. The elongated filopodia appeared to bridge the gaps among the fibroblasts after 24 hours incubation. Further incubation to 72 hours, a greater number of platycytes were found to be joined together by lamellopodia. CONCLUSION: 3T3 fibroblasts could grow and survive on blood fibrin clot in the low-serum medium containing rhbFGF, and a combination of blood fibrin clot and rhbFGF may have over proportional effects on wound healing.

OBJECTIVE:To discuss the accuracy of detecting tacrolimus(FK506) concentration in whole blood by ELISA and its application in organ transplantation.METHODS:The ELISA was used to detect FK506 valley point concentrations in 5 liver transplanted recipients at different postoperative periods .Based on the results combined with clinical findings, the dosages were adjusted.The accuracy of the method and guidance action in FK506 clinical application were described.RESULTS: In 131 detections of 350 samples, the results of quality control samples were all in the control range .The detecting RSDs of high and low concentration quality control samples were 9.09% and 11.90%, respectively.The control range of FK506 concentrations in whole blood were similar to that reported in literature .CONCLUSION :ELISA is a sensitive and specific method for routine FK506 concentration monitoring in whole blood,which is suitable for application in hospital.

Objective: To prepare an adenovirus, Ad-CD, expressing bacterial cytosine deaminase(CD),and use it for tumor suicide gene therapy. Methods: We constructed a recomb ined adenoviral vector carrying CD or LacZ. 293 packaging cell was trans fected by the newly-constructed plasmid and generated the infectious virus. The n the adenovirus was used to infect C26 cell in vitro. Results: The growth of Ad-CD-infected cell was obviously surpressed after admini stration of 5-FC. Conclusion: CD gene carried by adenoviral vec tor is effective for tumor cell suicide gene therapy in vitro.