Preoperative Evaluation of V-Y Flap Design Based on Computer-Aided Analysis.

V-Y flap is widely used in plastic surgery as an important technique for reconstructing deformities and improving appearance. In this paper, a geometrical parameter model and finite element analysis were used to study the rationale of the proposed V-Y flap design and the preoperative evaluation of the V-Y flap design. First, a geometric parameter model of the V-Y flap was established to analyze the five key geometric relationships affecting the flap structure and obtain a reasonable plan for the V-Y flap design through the crossing constraint relationship. Second, in order to verify the effectiveness of the V-Y flap design, the suture and release states of the V-Y flap during surgery were evaluated based on a simulation model of the V-Y flap generated by finite element analysis software. The results revealed that the approach proposed in this paper provides a feasible method for clinical V-Y flap design.

Recombinant snake venom metalloproteinase inhibitor BJ46A inhibits invasion and metastasis of B16F10 and MHCC97H cells through reductions of matrix metalloproteinases 2 and 9 activities.

Studies have shown that the recombinant BJ46a (rBJ46a) protein can reduce matrix metalloproteinase (MMP) activities and inhibit invasion and metastasis of melanoma cells. Here, we optimized the Pichia pastoris system to evaluate rBJ46a protein as an anticancer agent. The Enzchek gelatinase/collagenase assay showed that rBJ46a inhibited MMP activities (IC50=0.119 mg/ml). Kinetic analyses using a series of double reciprocal Lineweaver-Burk plots (1/V vs. 1/S) showed a competitive mode of inhibition with rBJ46a with inhibitory efficiency against MMPs (Ki=13.6 nmol/l). Matrigel invasion assays showed significant activity of rBJ46a on tumor cells. For lung colonization assays, C57BL/6 mice were inoculated in the lateral tail vein with B16F10 cells and were treated with three i.v. injections of rBJ46a (1, 2, and 4 mg/kg) 24 h before cell inoculation, and 2 and 24 h after cell inoculation. Administration of rBJ46a suppressed lung tumor colony formation significantly. For spontaneous metastasis assays, MHCC97H cells were inoculated subcutaneously into nude mice. After 24 h, rBJ46a was administered by i.p. injections: 1, 2, and 4 mg/kg once daily for 6 days. rBJ46a decreased lung tumor colony formation significantly. Gelatin zymography showed that MMP2/MMP9 enzymatic activities in tumor cells were suppressed by rBJ46a in a dose-dependent manner, and the Km values of rBJ46a against MMP2 and MMP9 activities that were expressed in both B16F10 and MHCC97H cells were 3.6 and 1.4 µmol/l, respectively. Thus, rBJ46a can inhibit the invasion and metastasis of tumor cells by reducing MMP2/MMP9 activities, indicating that rBJ46a may be a novel therapeutic agent for antimetastasis of tumor cells.

High-level expression, purification, characterization and structural prediction of a snake venom metalloproteinase inhibitor in Pichia pastoris.

Snake venom metalloproteinase inhibitor BJ46a is from the serum of the venomous snake Bothrops jararaca. It has been proven to possess the capacity to inhibit matrix metalloproteinases (MMPs), likely based on its structural similarity to MMPs. This report describes the successful expression, purification, and characterization of the recombinant protein BJ46a in Pichia pastoris. Purified recombinant protein BJ46a was found to inhibit MMPs. Structural modeling was completed and should provide the foundation for further functional research. To our knowledge, this is the first report on the large scale expression of BJ46a, and it provides promise as a method for generation of BJ46a and investigation of its potential use as a new drug for treatment of antitumor invasion and metastasis.