Detection of clarithromycin-resistant Helicobacter pylori in clinical specimens by molecular methods: A review.

Various molecular methods have been developed to rapidly detect clarithromycin (CLR) resistance in Helicobacter pylori isolates in clinical specimens. All of these assays for detecting CLR resistance in H. pylori are based on detection of mutations in the 23S rRNA gene. In this article, we summarise current knowledge regarding the detection of H. pylori CLR resistance in clinical specimens by molecular tests. The available data showed that restriction fragment length polymorphism (RFLP), 3'-mismatch PCR, DNA sequencing, the PCR line probe assay (PCR-LiPA) and fluorescence in situ hybridisation assay (FISH) are able to detect CLR-resistant H. pylori in clinical specimens with excellent specificity and sensitivity. However, several factors limit their clinical application, including fastidious, time-consuming preparation and low-throughput as well as carrying a risk of contamination. Furthermore, as an invasive method, FISH is not suitable for children or the elderly. Among the molecular methods, one that is most promising for the future is real-time PCR probe hybridisation technology using fluorescence resonance energy transfer (FRET) probes, which can rapidly detect CLR resistance with high sensitivity and specificity in biopsies and stool specimens, even though mixed infections are present in clinical specimens. Moreover, due to the advantages that this method is simple, rapid and economical, real-time PCR is technically feasible for clinical application in small- and medium-sized hospitals in developing countries. Second, with high sensitivity, specificity and throughput, DNA chips will also be a valuable tool for detecting resistant H. pylori isolates from cultures and clinical specimens.

Overexpression of integrin αv in the human nasopharyngeal carcinoma associated with metastasis and progression.

BACKGROUND: Integrins are cell-surface adhesion molecules, regulate normal cellular interactions, and which are consisting of α and ß subunits and facilitate signal transduction in a bidirectional manner. Tumor cells have been found to express a wide variety of integrins, overexpression of integrin αv has been detected in a growing number of human malignancy types, However, the reports obout expression of integrin αv in nasopharyngeal carcinoma (NPC) are very rare. OBJECTIVE: This study aims to detect the expression of integrin αv in NPC, and to evaluate the correlation between integrin αv expression and clinicopathological factors. METHODS: Real-time polymerase chain reaction (real-time PCR) assay and immunohistochemical staining were performed to detect the expression of integrin αv in NPC tissue samples. The correlation between the integrin αv expression and clinicopathological factors was evaluated. RESULTS: In NPC tissues, the expression levels of integrin αv mRNA was significantly higher than those in the nasopharyngeal inflammation tissues (P< 0.05), and the expression level were significantly correlated with T, N and clinical stage (all P < 0.05). Moreover, the expression rates of integrin αv protein in NPC tissues was 76.92%, significantly higher than that of nasopharyngeal inflammation tissues (6.25%, P< 0.05). We also observed that the protein expression of integrin αv was significantly related to T, N and clinical stage (all P< 0.05). CONCLUSIONS: All these findings suggest that overexpression of integrin αv is closely associated with metastasis and progression of NPC. Therefore, we can speculate that integrin αv could be effective prognostic markers in the future for individualized treatment of patients with NPC.

Enzymic colorimetry-based DNA chip: a rapid and accurate assay for detecting mutations for clarithromycin resistance in the 23S rRNA gene of Helicobacter pylori.

Macrolide drugs, such as clarithromycin (CAM), are a key component of many combination therapies used to eradicate Helicobacter pylori. However, resistance to CAM is increasing in H. pylori and is becoming a serious problem in H. pylori eradication therapy. CAM resistance in H. pylori is mostly due to point mutations (A2142G/C, A2143G) in the peptidyltransferase-encoding region of the 23S rRNA gene. In this study an enzymic colorimetry-based DNA chip was developed to analyse single-nucleotide polymorphisms of the 23S rRNA gene to determine the prevalence of mutations in CAM-related resistance in H. pylori-positive patients. The results of the colorimetric DNA chip were confirmed by direct DNA sequencing. In 63 samples, the incidence of the A2143G mutation was 17.46 % (11/63). The results of the colorimetric DNA chip were concordant with DNA sequencing in 96.83 % of results (61/63). The colorimetric DNA chip could detect wild-type and mutant signals at every site, even at a DNA concentration of 1.53 x 10(2) copies microl(-1). Thus, the colorimetric DNA chip is a reliable assay for rapid and accurate detection of mutations in the 23S rRNA gene of H. pylori that lead to CAM-related resistance, directly from gastric tissues.