The majority of the viral hepatitis cases is caused by five hepatitis viruses (A,B,C,D,E). In 1997, TT virus was discovered. It was supposed that a number of the unknown hepatitis cases was caused by the TT virus. The aim of this study was to characterize TT viruses carried by healthy individuals and patients suffering from hepatitis of unknown origin in Hungary. TTV DNA was detected by seminested PCR with the commonly used N22 primers. Twenty of the 108 sera (18.5%) taken from healthy persons and 115 of the 228 sera (50.4%) of patients with hepatitis of unknown origin were found to be positive. The nucleotide sequences of 26 clones derived from 17 hepatitis patients and 15 clones from nine healthy persons were determined and a phylogenetic tree was constructed. Genotype 2 (group 1) was found to be the most frequent, but other group 1 genotypes (1, 6) and genotypes 8 and 17 of group 2 were also detected. Mixed TTV infections were found in eight cases (two healthy persons and six hepatitis patients). Variants belonging to the same group were carried in seven cases, and the presence of group 1 (genotype 2) and group 2 (genotype 8) TTV sequences were found in one single hepatitis patient.

The aim of this study was to investigate the genetic diversity of HIV-1 strains circulating in Slovenia. Proviral DNA isolated from peripheral blood mononuclear cells (PBMCs) of 20 randomly selected HIV-1-infected individuals was classified into subtypes by sequence-based phylogenetic analysis of the env (C2V3) and gag (p24) regions of the viral genome. The phylogenetic tree based on env C2V3 sequences showed that 15 of the 20 samples were subtype B, two A1, one F1, one CRF01_AE, and one CRF02_AG. The phylogenetic analysis of the gag gene yielded identical results expect for one sample that had a discordant subtype; it was identified as subtype A1 in the env and AE in the gag region. Our study confirmed that although subtype B predominates, other subtypes and circulating recombinant forms (CRFs) are also present in Slovenia. The high intrasubtype genetic diversity of subtype B sequences suggests a multiple introduction of subtype B strains into Slovenia.

The lentiviral protein Nef recruits cellular signalling proteins to lipid rafts at the cell membrane and acts thereby as a master regulator affecting the transcription of a series of cellular genes. By activating resting T cells, Nef creates an optimal environment for lentivirus replication. In human immunodeficiency virus (HIV) infected macrophages and microglial cells Nef activates the production of T-cell attracting chemokines and contributes to the development HIV infection associated brain damage. Nef also functions as an adaptor or connector protein downregulating CD4 and CCR5, the key receptor and one of the coreceptors for HIV. It also downregulates cell surface expression of a subset of class I MHC molecules which contributes to viral immune evasion. Extracellular, soluble Nef may facilitate the spread of T-cell-tropic HIV variants and mediate a switch in dominant replicating HIV strains (from macrophage-tropic to T-cell-tropic viruses) in AIDS (acquired immunodeficiency syndrome) patients. Virion-bound Nef enhances infectivity. Nef is a potential target of antiretroviral therapy and nef-deleted (attenuated) retroviruses have been considered as candidate vaccines against HIV. We suggest that nef-deleted or highly mutated defective HIV (dHIV) genomes interfere with replication of "wild type" HIV in certain long-term non-progressor individuals. This implies that introduction of artificially constructed dHIV genomes (by infusion of leukocytes carrying dHIV proviruses) into HIV infected individuals could slow disease progression and could be considered as a therapeutic possibility.

HIV-1 was isolated from a child at 6 and 9 months of age, proving the vertical transmission of infection from the mother with AIDS. The p24 antigen test of the plasma at 9 months of age was positive as well. A positive PCR reaction was detected in J34 cells, infected with the supernatant of the peripheral blood lymphocytes of the child. According to phenotypic characterization, the virus proved to be a SI (syncytium inducing) isolate, growing in PBL, MT2, J34 and other T and monocytic cell lines. The isolate was AZT sensitive. Two methods were applied for genotypic characterization: 1. Heteroduplex mobility assay (HMA), 2. Sequence analysis of a part of the env gene. On the basis of both of these methods, this virus belongs to the B subtype of HIV-1, which is prevalent mainly in Europe and in the USA. The neurological status of the child was followed regularly. At autopsy the presence of p24 antigen was detected in glial cells of the frontal cortex, proving the presence of the virus in the brain. A retardation of the development of the central nervous system could be observed as well.

Spinal deformity is a serious economic and animal welfare problem in intensive fish farming systems, which will be a significant unsolved problem for the fish sector. The aim of this study was to determine the relative expression of genes (Akt1 substrate 1, Calreticulin, Collagen type I alpha 2 chain, Corticotropin-releasing hormone, Chromodomain-Helicase DNA-binding, Growth hormone, Insulin like growth factor 1, Myostatin, Sine oculis-related homeobox 3, Toll-like receptor 2) in different tissues associated with spinal deformity and to determine the macroelement (calcium, magnesium, phosphorus, potassium, sodium, sulfur) and microelement (barium, copper, iron, manganese, strontium, zinc) content of spine in healthy and deformed common carps (Cyprinus carpio) in Hungary. The mRNA levels of the genes were measured in 7 different tissues (abdominal fat, blood, brain, dorsal muscle, genitals, heart, liver) by qRT-PCR. Correlations between gene expression and element content were analyzed by using linear regression and Spearman rank correlation. In a total of 15 cases, we found a statistically significant connection between gene expression in a tissue and the macro- or microelement content of the spine. In these contexts, the genes Akt1 substrate 1 (3), Collagen type I alpha 2 chain (2), Corticotropin-releasing hormone (4), Insulin-like growth factor 1 (4), and Myostatin (2), the tissue’s blood (3), brain (6), heart (5), and liver (1), the macroelements sodium (4), magnesium (4), phosphorus (1) and sulfur (2) as well as the microelement iron (4) were involved. We also found statistically significant mRNA level differences between healthy and deformed common carps in tissues that were not directly affected by the deformation. Based on our results, genes regulating the nervous system and growth, elements, and tissues are the most associated components in the phenomenon of spinal deformity. With our study, we wish to give direction to and momentum for the exploration of these complex processes.