Objectives A new method for the detection of PCR ampli fied DNA in capillary electrophoresis and laser induced fluorescence (CE LIF) system based on molecular beacons hybridization is described.Methods The method is based on the hybridization of molecular beacons into the amplification product, then separating the hybridized product with CE LIF system. This method was applied to the detection of p73exon3, p53exon5 and p16exon2 for gastric carcinoma. Results Detected with CE LIF molecular beacons method, the wild type percent of p73exon3 is 100%, same as SSCP; p53exon5 is 60 0%, while SSCP is 63 3%, P=0 99; p16exon2 is 20 0%, same as SSCP(20 0%).Conclusion The results demonstrate that the specific peaks appeared in wild type samples while no peaks or unspecific peaks in mutation ones. The results showed correlation with the results of PCR SSCP. The method is able to develope as a clinical screening method for tumor suppressor genes to diagnose carcinoma.

BACKGROUNDIt has been proved that hypoxia is closely related to oncogenesis and development of tumor. The aim of this study is to observe the effect of dexamethasone on expression of hypoxia inducible factor 1α (HIF-1α) and vascular endothelial growth factor (VEGF) in lung tissues of hypoxic mice, and to investigate the relationship between hypoxia and angiogenesis and mechanism of dexamethasone.

METHODSThe Kunming mice were randomly divided into control group and three experimental groups (3-day hypoxia group, 6-day hypoxia group, and hypoxia+dexamethasone group). HIF-1α and VEGF protein expression was detected in lung tissues of mice by immunohistochemistry.

RESULTSExpression of HIF-1α and VEGF significantly increased in hypoxia group compared with control group (P < 0.05). Compared with hypoxia group, expression of HIF-1α and VEGF decreased dramatically in hypoxia+dexamethasone group (P < 0.05). A positive correlation was found between the expression of HIF-1α and VEGF (r=0.730, P=0.007).

CONCLUSIONSHypoxia can increase the expression of VEGF and HIF-1α in lung tissues of mice. Dexamethasone can inhibit the expression of VEGF and HIF-1α of hypoxic mice and it may have anti-angiogenetic effect.