In the mid-1990s commercial G-LCR kits were developed for the detection of C. trachomatis, N. gonorrhoeae, and M. tuberculosis (Abbott), and these assays played a significant role in clinical STD (sexually transmitted disease) diagnostics. Due to modernized regulations in quality assurance, modifications performed in the manufacturing process and component changes made these assays not as robust as they used to be, resulting in high failure rates in internal testing since 2001 (personal communication, Judy H. Yu, Abbott, IL). In 2003, Abbott discontinued the distribution of its LCR-based diagnostic products and is now using PCR-based technology for its commercial diagnostic kits (LCx HCV and LCx HIV). Currently, there are no commercial LCR-based nucleic acid amplification tests on the market, and in molecular STD diagnostics LCR has lost ground against PCR. Nonetheless, DNA ligation assays continue to play an important role in molecular diagnostics, as is exemplified by the development of ligase-detection PCR (LD-PCR) and the use of LDR in combination with DNA array technology. DNA ligase was used in combination with PCR in a probe amplification assay named LD-PCR to increase the accuracy and sensitivity of target nucleic acid determi-nation. This method utilizes a capture probe for target isolation, two hemiprobes for target detection, and a PCR step to amplify the ligated full probe. Ligase-detection PCR was more sensitive than conventional RT-PCR for the detection of HCV DNA in formalin-fixed paraffin-embedded liver specimens. Ligation assays are useful methods for mutation analysis on microarray platforms and are gaining wide attention due to their excellent discriminatory power of allele variants. Ligase detection reaction was successfully used on microarrays for discriminating between different bacterial groups, for rapid and sensitive identification of drug-resistant M. tuberculosis strains, and, in combination with PCR, for detecting and genotyping human papillomavirus1-38-1 or for characterizing p53 mutations in a multiplex PCR/LDR assay.[39-41]
Was this article helpful?
The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.