Genetic diversity and structure of the West Balkan Pramenka sheep types as revealed by microsatellite and mitochondrial DNA analysis.

Several different phenotypes of the native Pramenka sheep have been developed in the Balkan region for different environmental and socio-cultural conditions. Animals from seven West Balkan Pramenka sheep types were analysed for 15 microsatellite markers and for mitochondrial DNA (mtDNA) and the results were used to assess genetic variation within and among the types and to infer the genetic population structure of the Pramenka sheep. Mean expected heterozygosity and allelic richness over the microsatellite loci and sheep types were 0.78 and 7.9, respectively. A Bayesian statistical method for estimating hidden genetic structure suggested that a core of the largest panmictic population was formed by Serbian, Kosovan, Bosnian, Montenegrin and Albanian types, while Croatian and Macedonian types comprised two other main populations, respectively. Mitochondrial DNA analysis revealed two mtDNA haplogroups in the Pramenka sheep, B and A, with a frequency of 93.7% and 6.3%, respectively. A total of 60 mtDNA haplotypes were found in 64 animals sequenced, and the mean nucleotide and haplotypic diversities over the types were 0.013 and 0.945, respectively. Molecular analysis suggests that the West Balkan Pramenka sheep types have their origins in two distinct maternal lineages of domestic sheep and different Pramenka phenotypes tend to form few panmictic populations. The Pramenka sheep represents a valuable resource of genetic diversity in sheep.

Reverse transcriptase/polymerase chain reaction analyses of hemodialysis ultrafiltrates and sera of hepatitis C virus positive patients.

The hepatitis C virus is a highly prevalent infection among chronic dialysis patients and represents one of the major problems of hemodialysis units. Hepatitis C virus transmission occurs either by blood transfusion or nosocomially. One of the proposed pathways of nosocomial transmission of the hepatitis C virus is cross-contamination through the dialysis procedure. In an effort to elucidate whether the hepatitis C virus may pass across the hemodialysis membrane, we have performed analyses of ultrafiltrates collected in different stages of hemodialysis treatments, using different types of hemodialysis membranes and different types of dialysis machines. Samples collected from the dialysis compartment during the rinsing of the blood compartment at the end of the hemodialysis treatment were also analyzed. The hepatitis C virus was found in 17 out of 58 ultrafiltrate samples taken at different times of the hemodialysis treatment. Moreover, the hepatitis C virus was present in 15 out of 17 samples collected from the dialysate compartment during the saline solution rinsing step of the blood compartment. The presence of the hepatitis C virus had no strict correlation with the type of dialysis membrane or with the type of dialysis machine. Although the results suggest that the passage of the hepatitis C virus during the hemodialysis treatment is multi-factorial and case- specific, the most critical point is when the blood is flushed out with physiological saline.