Hepatitis C virus (HCV) is a major cause of hepatitis among patients treated with maintenance hemodialysis. Blood transfusion appears to be the primary risk factor, but nosocomial transmission of HCV in the dialytic environment has been hypothesized. We addressed this issue by analyzing the individual variation of genomic sequences of HCV in 28 patients on chronic hemodialysis (HD) from the same department and 25 environmentally unrelated patients with HCV-related liver disease. Genome variations of HCV were studied by single strand conformation polymorphism (SSCP) analysis of polymerase chain reaction products obtained from the 5'-untranslated region of the viral genome and by sequence analysis. Six different SSCP patterns were identified in HD patients versus 16 in control patients. Among HD patients the three more frequent SSCP patterns accounted for 85% of observations, while in the control group each pattern was found in 4 to 12% of patients. The ability of SSCP to discriminate sequence variation was proven by sequence analysis which confirmed identity/diversity of sequences selected by SSCP. Moreover, sequence analysis permitted a recognition of the most frequent genome observed in HD patients as a type 4 HCV, which is considered to be rare in the Italian population. The relative homogeneity of HCV variants in HD patients treated in the same HD and the high prevalence in this unit of a rare viral variant support the possibility of a nosocomial transmission of HCV in the dialytic environment.

BackgroundIn this study we aimed at quantifying the possible errors which may occur when assessing specific reference planes and linear derivants on cephalometric radiographs traced manually and digitally. Furthermore, we have compared the precision of the tracings according to both the two- and three-dimensional (2D and 3D respectively) techniques and between clinicians.FindingsWe have obtained via cone beam computed tomography (CBCT) archive of the orthodontics department of the University of Milan 20 cone beam CT radiographs from which we have obtained 20 latero-lateral radiographs. Five independent clinicians referred to as A, B, C, D, E have been randomly selected to trace both radiographs maintaining the same working and lighting conditions to minimize the possibility of operator- and environment-dependent errors from occurring. The results have been statistically assessed by Student’s t test. The comparison of the data gathered from the tracings in 2D and 3D shows that certain measurements have statistically significant differences. Particularly, the difference in the measurements of the sagittal dimension of the mandible and the anterior and posterior nasal spines has resulted to be statistically significant. The results of the intra-operator comparison proved that the 3D technique is extremely precise.ConclusionOur study determines that the 3D technique allows to obtain more precise results and with several advantages when compared to the conventional technique such as a true representation of the anatomical structures, less risk of errors occurring due to clinician skills and absence of overlapping anatomical structures.

Detection of hepatitis C virus genome is the only method currently available for detecting viremia in infected individuals. We describe a substantial simplification of current methods for viral RNA reverse transcription and polymerase chain reaction amplification, which allows cDNA synthesis and nested amplification in a single tube; this is achieved through compartmentalization of the reagents for the two reactions with a wax barrier. This procedure retains a high sensitivity: analysis of serum samples from hemodialysis patients, a high-risk group for hepatitis C virus infection, confirmed the presence of the virus in 88% of antibody-positive patients and detected viremia in patients without serological or biochemical evidence of hepatitis C virus infection.

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