Optimized Suppression of Adducts in Polymerase Chain Reaction Products for Semi-Quantitative SNP Genotyping by Liquid Chromatography-Mass Spectrometry

Oberacher,H.; Parson,W.; Hölzl,G.; Oefner,P.J.; Huber,C.G.; While electrospray ionization mass spectrometry has shown great potential for the identification of genotypes in DNA sequences amplified by polymerase chain reaction (PCR), the quantitative determination of allele frequencies remains challenging because of the presence of cationic adducts in the mass spectra which severely impairs accuracy of quantitation. We report here on the elaboration of an optimized desalting protocol for ion-pair reversed-phase high-performance liquid chromatography-electrospray ionization mass spectrometry (ICEMS) of PCR amplicons which facilitates the genotyping of single nucleotide polymorphisms (SNPs). [Read More]

Phylogenetic and genotypic resistance analysis of HIV-1 infected patients in Austria

Falkensammer,B.; Doerler,M.; Kessler,H.H.; Puchammer-Stoeckl,E.; Parson,W.; Taveira,N.; BACKGROUND: Analysis of HIV-1 subtypes and genotypic resistance have been shown to be relevant for epidemiologic and therapeutic studies or for vaccine development. In Europe, the majority of HIV-1 isolates belong to subtype B. Due to migration an increasing incidence for additional subtypes and complex recombinant forms are expected. OBJECTIVES AND STUDY DESIGN: To evaluate the prevalence of HIV-1 subtypes in Austria, 188 plasma samples of treatment experienced patients were investigated. [Read More]

Results of a collaborative study of the EDNAP group regarding mitochondrial DNA heteroplasmy and segregation in hair shafts

Tully,G.; Barritt,S.M.; Bender,K.; Brignon,E.; Capelli,C.; mo-Simonin,N.; Eichmann,C.; Ernst,C.M.; Lambert,C.; Lareu,M.V.; Ludes,B.; Mevag,B.; Parson,W.; Pfeiffer,H.; Salas,A.; Schneider,P.M.; Staalstrom,E.; A collaborative exercise was carried out by the European DNA Profiling Group (EDNAP) in order to evaluate the distribution of mitochondrial DNA (mtDNA) heteroplasmy amongst the hairs of an individual who displays point heteroplasmy in blood and buccal cells. A second aim of the exercise was to study reproducibility of mtDNA sequencing of hairs between laboratories using differing chemistries, further to the first mtDNA reproducibility study carried out by the EDNAP group. [Read More]