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Abstract: Determination of inter- and intragenotype stability and variability is the basic tools for the molecular epidemiology and evolutionary investigation of measles virus (MV). We made a comparison between complete genome sequences of four MVs (two wt MV strains—WA.USA/17.98 and 97-45881, and two SSPE MV strains—MVs/Zagreb.CRO/47.02/and MVs/Zagreb.CRO/08.03/), all belonging to genotype D6. Results of analyses clearly confirm that MV genome continuously changes within the viruses of the same or different genotypes by accumulation of mutations in different parts of the genome. Only a small number of these accumulated mutations induce amino acid substitutions and thus possibly introduce new biological characteristics or a new genotype over a long time period. This study clearly reveals a long untranslated region between M and F genes as the most variable region of the MV genome and detects the presence of unique residues on the level of the entire genome as a new important parameter in the investigation of molecular evolution of MVs. [Copyright &y& Elsevier]

An in vitro expression of delayed-type hypersensitivity to tuberculin was tested in Mantoux positive and Mantoux negative persons. Their lymphocytes and monocytes were isolated from venous blood and incubated in vaseline chambers with or without tuberculin. In the presence of tuberculin, a substantially lower percentage of monocytes from Mantoux positive persons spread, than monocytes From Mantoux negative persons. This antigen-induced inhibition of monocyte spreading seems to be a reliable measure of tuberculin hypersensitivity, since it occurs only in Mantoux positive persons and correlates well with the intensity of the tuberculin skin reaction. Reproducibility of the test and the speed with which it is performed could constitute a basis for the use of monocyte spreading inhibition in clinical studies of cell-mediated immune reactions. [ABSTRACT FROM AUTHOR]

Abstract: The two most commonly used methods for the determination of a virus potency are plaque assay and 50% cell culture infective dose (CCID50) assay, both based on cytopathic effect observation. We compared the potency estimates obtained by plaque and CCID50 assays for nine mumps virus strains that produce different cytopathic effects in Vero cells. The ratios of CCID50 and plaque assay quantification results differed for different strains and were in a range of 0.66–10, indicating that quantification results for some mumps virus strains are almost identical regardless of whether CCID50 or plaque method is used, while the potency estimates of other strains strongly depend on the choice of the assay. [Copyright &y& Elsevier]

Abstract: A residual risk of HCV infection by different blood products exists due to blood donations collected during the serological window period in the early stages of infection. The aim of this study is nucleic acid amplification technique (NAT)-based screening of the anti-HCV negative plasma pools obtained from various Croatian transfusion centres between 2001 and 2003 for HCV RNA. During this period 2647 anti-HCV negative plasma pools were tested by NAT and 12 (0.45%) HCV RNA positive pools were detected. In comparison to the results of our previous study [Forčić D, Zgorelec R, Branović K, Košutić-Gulija T, Šantak M, Mažuran R. Incidence of hepatitis C virus RNA in anti-HCV negative plasma pools in Croatia. Transfus Apher Sci 2001;24:269–78], a remarkable decrease in the number of positive plasma pools (from 2.1% to 0.45%) was demonstrated. [Copyright &y& Elsevier]

Two cases of subacute sclerosing panencephalitis (SSPE), diagnosed in Croatia in 2002, were investigated. The coding regions of the matrix (M), hemagglutinin (H) and nucleoprotein (N) genes of measles virus were sequenced following direct RT-PCR amplification of viral RNA extracted from brain tissue. Phylogenetic analysis of the sequences of H and N genes, showed that both strains belonged to genotype D6. No vaccine strain was detected although both patients had been previously immunized. The comparison of analyzed sequences of two SSPE causative viruses with corresponding sequences of D6 genotype and with each other revealed a number of mutations in N and H gene sequences. In comparison to the Edmonston reference strain, the M gene of the SSPE viruses showed the characteristic biased hypermutation and a premature termination codon in one of the patients. [Copyright &y& Elsevier]