To explore the effects of different organic solvents including trimethylglycine on the PCR amplification of G+C rich DNA templates,two high G+C containing DNA templates (cyclin dependent kinase inhibitor gene ARF and IGFR II) were amplified using standard PCR and modified PCR with the addition of glycerin, dimethylsulfoxide (DMSO), formamide and trimethylglycine respectively. There were no specific amplified products, when standard PCR and modified PCR with the addition of glycerin, DMSO and formamide were used to amplify the G+C rich ARF and IGFR II genes. But the two genes could be specifically amplified with the addition of optimal concentration of trimethylglycine in the PCR mixture. These results indicate that trimethylglycine can abolish or reduce the formation of second structures in G+C rich DNA regions and promote the amplification of high G+C containing DNA templates.

AIM: To study the effect of p19ARF on the biological behavior of human leukemia cells. METHODS: p19ARF was cloned in eukaryotic expression vector pcDNA3.1 and transferred into INK4a/ARF locus-deficient leukemia cells HEL and K562. The changes in biological characteristics of the two p19ARF-transfected cells were observed. RESULTS: The growth of the p19ARF-transfected HEL cells was significantly inhibited compared with the vector-transfected cells; Cell cycle analysis showed that the expression of foreign p19ARF gene resulted in G1 phase cell cycle arrest and apoptosis cell death in some of HEL cells. However, p19ARF had no marked effects on the growth of K562 cells with p53 gene mutation and did not induce apoptosis in K562 cells. CONCLUSION: p19ARF suppressed the growth of leukemia cells by p53 -dependent pathway.

Objective To assess the significance of the right paraesophageal node(Ⅵb area) dissection in cN0 stage papillary thyroid microcarcinoma(PTMC)central lymph node dissection.Methods The clinical data of three hundred and five cN0 PTMC patients who underwent radical thyroidectomy from 2010 to 2015 was retrospectively analyzed.The metastasis rate of central compartment(Ⅵa area.Ⅵb area)and the clinical data were collected and analyzed.Results 305 cN0 stage PTMC patients underwent total thyroidectomy and bilateral central compartment dissection or right lobectomy combined with ipsilateral central compartment dissection,the mean diameter of the tumors was 6.75 mm.The incidence rate of central compartment metastasis was 35%.The incidence rate ofⅥb area metastasis was 11.1%.The status ofⅥb area metastasis was correlated with major clinicopathologic parameters such as sex,age<45,tumor diameter≥0.8 cm,bilateral multiple lesions, capsule invasion,VI a lymph node metastasis≥3 were all related risk factors of PTMC VIb area metastasis(χ2=6.913,4.241,4.517,5.185,12.400,34.745,P<0.05).Conclusion Because of the high rate of central lymph node metastasis in patients with PTMC and the poor efficiency in the evaluation for central lymph node metastasis before operation,the right paraesophageal lymph nodes(Ⅵb area)dissection is needed to be done in cN0 stage PTMC patients with tumor size≥0.8 cm,multifocal lesions,membrane invasion,Ⅵa area metastasis≥3,especially male patients.