Procyanidins inhibit tumor angiogenesis by crosslinking extracellular matrix.

OBJECTIVE: Procyanidins (PC) are widely available natural polyphenols. The present study is designed to investigate if PC can inhibit angiogenesis in lung adenocarcinoma xenografts through crosslinking vascular extracellular matrix (ECM) and preventing proteolysis by matrix metalloproteinases (MMPs). METHODS: Using the in vitro MMP-2 proteolysis and in vivo subcutaneous implantation models, we investigated if PC crosslinking inhibits MMP-mediated proteolysis. Using a cultured cell detachment assay, an in vitro angiogenesis assay, and a cell proliferation assay, we investigated if PC inhibits MMP-2-mediated endothelial cell detachment, angiogenesis, and cell proliferation, respectively. Using tumor xenografts, we evaluated if PC can inhibit growth of lung adenocarcinoma. RESULTS: PC crosslink vascular ECM proteins, protecting them against proteolysis by MMPs in vitro and in vivo, protecting cultured human umbilical vein endothelial cells from detachment by MMP-2, and inhibiting in vitro angiogenesis. However, PC (0.75-100 µg/ml) did not inhibit vascular and tumor cells proliferation. PC injections (30 mg PC/kg bodyweight) in situ had anticancer effects on xenografts of lung adenocarcinoma, most likely by inhibiting angiogenesis during ECM proteolysis by MMPs. CONCLUSION: The results suggest that PC may be important MMP inhibitors that can be used as therapeutic anticancer agents.

Design, simulation, and optimization of a miniaturized device for size-fractioned DNA extraction.

Fraction collection following electrophoresis has many applications in biology analysis. These assays typically need to identify specific fractions in the separated sample for further processing and require extraction of one or a group of fragments. Unfortunately, the conventional methods involve cumbersome procedures and are not amenable to integration, automation, and extraction of microscale samples. In this work, we present a scheme of chip-based electroelution for the extraction of DNA fragments, which allows the isolation and collection of target DNA fragments in a single device. Both theoretical analysis and experimental results have shown that there are some cross-contaminations from adjacent bands and a little loss of DNA recovery during target DNA extraction with the prototype miniaturized device. In order to improve the purity and yield of the extracted DNA fragment, an optimal channel configuration for DNA recovery miniaturized device was proposed. The simulations and the experimental results are in good agreement and confirm that with the optimized device design a high-efficiency DNA extraction is achieved.

[Establishment of a method with micro-channel electrophoresis for detecting the mutations of isoniazid-resistant genes in Mycobacterium tuberculosis].

OBJECTIVE: To establish a method for the detection of isoniazid resistance-associated mutations in katG gene and inhA gene in Mycobacterium tuberculosis with single-stranded conformation polymorphism (SSCP) analysis by the micro-channel electrophoresis chip system. METHODS: The polymer solutions of acrylamide and its derivatives were used for sieving matrices with small amount of acridine orange as the fluorescent tag. A novel pair of primers was designed to link an extra segment that could be base paired with the mutation region to the PCR products of wild type inhA gene, which made the single strands of wild type inhA fragments present a unique conformation. RESULTS: The wild type fragments of katG gene and the fragments with mutation at codon 315 can be distinguished, and the inhA fragments with wild type and mutated regulatory sequence can be distinguished by this method. Twenty-two out of the 23 resistant strains were detected from 30 clinical isolates, the efficiency being 95%. CONCLUSION: It is demonstrated the high speed and sensitivity in detecting the mutations of isoniazid-resistant genes in Mycobacterium tuberculosis by micro-channel electrophoresis, and this method may be applicable in clinical detection of isoniazid-resistant strains.

A signal process method for DNA segments separation in micro-channel electrophoresis.

This paper presents a signal process method for DNA segments separation in micro-channel electrophoresis. It is developed and optimized by using a laser induced fluorescence (LIF) based detection system. In this detection system, signal is sampled and processed through a novel signal process module. The results show that this signal process method provides good signal-to-noise ratios and lower limit of detection (LOD).