Real-time fluorescence PCR-molecular beacon assay for detecting mutations in rpoB genes of rifampin-resistant Mycobacterium tuberculosis / 中华检验医学杂志

Objective To establish a rapid method to detect mutations in rpoB genes of rifampin-resistant Mycobacterium tubereulosis in dinical specimens using Real-time fluorescence PCR molecular beacon assay.Methods 174 strains of Mvcobacterium tuberculosis clinical isolates were analyzed using real-time fluorescence PCR molecular beacon assay foilowed with DNA sequencing while 12 strains of NTM and 4 strains of bacteria other than Mycobacterium tuberculosis were used as the contrast.Results Eighty-two 89.1 of 92 rifampin (RIF)-resistant strains and 3 of 82 RIF-sensitive strains were found to harbor mutation in the rpoB gene using real-time fluorescence PCR-molecular beacon assay.The specificity, sensitivity,and accuracy of this assay were 96.3%,89.1%,and 92.5%,respectively-Eithty-three of 92 RIF-resistant strains and 1 of 82 RIF-sensitive strains were found to harbor mutation in the rpoB gene using the direct DNA sequencing.The specificity,sensitivity,and accuracy of the direct DNA sequencing were 98.8,90.2%,and 94.2%,respectively.As compared with real-time PCR molecular beacon assay,171 of 174(98.3%)strains of myeobactefium tuberculosis clinical isolates had the salne results.Conclusion Real-time fluorescence PCR-molecular beacon assay can be used as a rapid screen method to detect RIF-resistant isolates.

Monocyte chemoattractant protein-1 mRNA in human intracranial aneurysm walls / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the pathological course in intracranial aneurysms.</p><p><b>METHODS</b>Normal intracranial artery tissue (cortex fistulization) from 1 case, ruptured aneurysms tissuses from 11 cases, unruptured aneurysm tissues from 2 cases were obtained by neurosurgical excision. Routine HE staining was used to observe histological characteristics. In situ hybridization was used to observe the expression of the monocyte chemoattractant protein-1 (MCP-1) mRNA in the walls of the normal artery and aneurysms.</p><p><b>RESULTS</b>By the HE staining showed that the wall of the ruptured aneurysms (10 cases) and unruptured ones (2 cases) had increased intima and connectivum extima. The fibroblast in the intima was arrayed in the disorder. Monocyte-like cells can be seen in the whole aneurysm wall. In one case aneurysms wall (ruptured) glass-like fiber structure was left over, few cells could be seen. In 9 cases, mural thrombus was found. The thrombus represented with organization. In situ hybridization, MCP-1 mRNA was not detectable in the normal artery. The hybridization signal could be observed in the ruptured aneurysms (10 cases) and unruptured ones (2 cases) often in the intima. MCP-1 mRNA appeared to be expressed by fibroblast cells in its cytoplasm. Monocyte-like cells had little cytoplasm, and the signal was seldom seen. The hybridization signal was discontinuous in the intima, MCP-1 mRNA expressed where fibroblast and monocyte-like cells assembled. One ruptured aneurysm had no signal because there were no cells only glass-like fiber. Mural thrombus showed upregulated hybridization signal in the cytoplasm of fibroblasts, phlogocytes and endotheliocytes of its micrangium.</p><p><b>CONCLUSION</b>The pathological representation of the ruptured and unruptured aneurysms and the upregulated expresion of MCP-1 in the aneurysm wall suggest that the development of aneurysm may be a course of chronic inflammation in which main inflammatory cells are monocyte-like cells.</p>