Background
Dried blood spots (DBS) are collected universally from newborns and may be valuable for the diagnosis of congenital Cytomegalovirus (CMV) infection. The reported analytical sensitivity for DBS testing compared to urine or saliva varies greatly across CMV studies. The purpose of this study was to directly compare the performance of various DNA extraction methods for identification of CMV in DBS including those used most often in CMV studies.
Study design
Whatman® Grade 903 filter paper cards were spotted with blood samples from 25 organ transplant recipients who had confirmed CMV viremia. Six DNA extraction methods were compared for relative yield of viral and cellular DNA: 2 manual solution-based methods (Gentra Puregene, thermal shock), 2 manual silica column-based methods (QIAamp DNA Mini, QIAamp DNA Investigator), and 2 automated methods (M48 MagAttract Mini, QIAcube Investigator). DBS extractions were performed in triplicate followed by real-time quantitative PCR (qPCR).
Results
For extraction of both viral and cellular DNA, two methods (QIAamp DNA Investigator and thermal shock) consistently gave the highest yields, and two methods (M48 MagAttract Mini and QIAamp DNA Mini) consistently gave the lowest yields. There was an average 3-fold difference in DNA yield between the highest and lowest yield methods.
Conclusion
The choice of DNA extraction method is a major factor in the ability to detect low levels of CMV in DBS and can largely account for the wide range of DBS sensitivities reported in studies to date.
Pathogenic Yersinia strains were isolated between December 1998 and April 1999 from 37 wild animals: rabbit (Lepus europeus), boar (Sus scrofa scrofa), asiatic jackal (Canis aureus), red fox (Vulpes vulpes), mouflon (Ovis musimon), european river otter (Lutra lutra), beech marten (Martes foina), polecat (Musleta putorius) and wild cat (Felis silvestris). It was established that among the wild animals Y. enterocolitica strains of serotype 0:3 predominated, accompanied by Y. pseudotuberculosis strains of serotype 0:3. In one sample from asiatic jackal and one sample from rabbit, Y. enterocolitica serotype 0:8 was isolated. Yersinia enterocolitica and Y. pseudotuberculosis strains were isolated from tonsils and tongues as well as from the viscera--lung, liver, heart, spleen, kidney and lymph nodes, mainly in young animals (1-2 years of age). The results showed that wild animals are a possible natural reservoir for pathogenic Y. enterocolitica and Y. pseudotuberculosis and are included in the epidemiological chain of yersinioses.
S U M M A R Y3-D P-wave velocity anomaly patterns, the geometry of the Hellenic WadatiBenioff zone and of the seismically active fracture zones in the overlying continental wedge, and the depth distribution of seismogenic properties (seismic activity, energy and b value) for the Aegean region are examined in this study. T h e western and eastern parts of the area studied differ significantly in terms of the depth distribution of the considered seismological parameters and the velocity structures. The results indicate different physical conditions in the western and eastern parts of the region in question. D a t a for the surface heat flow and the evolution of the volcanism in the Aegean region since t h e early Eocene are employed t o interpret t h e results of the present study. Possible geodynamic processes at the plate boundaries between Africa and Eurasia are discussed.
2-D group velocity and 3-D P-wave velocity patterns have been obtained from analyses of the group velocity dispersion of Rayleigh waves in south-eastern Europe and Asia Minor and of the P-wave travel-time residuals along ray-paths with a penetration depth of 100-300 km in southeastern Europe, Asia Minor and the eastern Mediterranean. The inversion procedure used is based on Backus-Gilbert formalism for linear inversion of travel-time data extended to 2-D and 3-D inhomogeneous media. Group velocity distributions have been obtained for periods T = 10,20, 30 s and are in a very good agreement with the well-known characteristics of the crust and upper mantle structure. They can be used for the construction of models of the crust in south-eastern Europe and Asia Minor. The P-wave velocity patterns obtained for the depth interval 50-300 km are discussed in terms of geophysical (regional isostatic anomaly, heat flow) data for the region. It is proposed that the correlation found to exist between the different mapped geophysical parameters can be explained by compositional changes in the low-velocity layer (the increase of the iron content in minerals).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.