Letter to the editor

Touchdown PCR: A rapid method to genotype Helicobacter pylori infection

Mitosis of mammary epithelial cell is foundation of mammal lactation. We developed a strategy of combined application of generation of longer cDNA fragments from the serial analysis of gene expression (SAGE) tags for gene identification (GLGI) to screen and identify genes influencing lactating ability of mammary epithelial cell in dairy goat. GLGI as a new tag identification technique was brought about with SAGE. Bzw2 was found as a candidate gene related to lactation by screening Long-SAGE library of mammary gland in dairy goat. Bzw2 cDNA was synthesized by switching mechanism at 5′-end of RNA transcript (SMART) technology. The mRNA level of Bzw2 was relatively higher in early lactation than in other development stages of mammary gland. The proliferation of mammary epithelial cell was inhibited by transfecting specific shRNA of Bzw2. The mRNA levels of Stat5, Csn2 and Prlr were also down-regulated, suggesting the lactating ability of mammary epithelial cell was attenuated after Bzw2 RNAi. The reduction of mammary epithelial cell growth and lactation by Bzw2 RNAi was rescued through over-expression of Bzw2. These results revealed that Bzw2 might play an important role in lactation though the molecular mechanism was still unclear.

Objectives: (1) To compare two stool antigen EIAs (HpSA, FemtoLab) and PCR of ureaseA and cagA in feces, with ¹³C-urea breath test (UBT). (2) To ascertain whether a simplified UBT (breath collection time = 10 min) is as reliable as the standard assay (30 min).

Design and Methods: Helicobacter pylori status was recorded in Group 1 (n = 187) by UBT, H. pylori stool antigen, ureA and cagA PCR in feces. UBT with 10, 20 and 30 min sampling was performed in Group 2 patients (n = 283).

Results: The sensitivity and specificity of HpSA, FemtoLab, and ureA were 67% and 99%, 90% and 96%, 35% and 98%, respectively. cagA results were positive in 16/48 H. pylori-positive, and in 5/100 H. pylori−negative patients. The results of UBT with a 10- and 30-min sampling strictly overlapped.

Conclusion: UBT with 10 min breath collection and FemtoLab stool antigen assay are the most reliable non-invasive tests to diagnose H. pylori infection.