Dietary polyamines promote the growth of azoxymethane-induced aberrant crypt foci in rat colon

We have examined whether dietary polyamines influence the formation and initial growth of azoxymethane (AOM)-induced aberrant crypt foci (ACF) in rat colon. Effects of a combination of dietary polyamines at three dose levels (putrescine: 50, 280, 740 nmol/g; spermidine: 10, 261, 763 nmol/g; spermine: 1, 31, 91 nmol/g) in the polyamine-poor AIN-76A diet were studied in animals in two different experimental situations: animals treated with AOM alone and animals treated with AOM + difluoromethylornithine (DFMO), a specific inhibitor of endogenous polyamine synthesis. In both experimental situations, dietary polyamines enhanced the growth of ACF, expressed as the number of large ACF (foci with three or more aberrant crypts, ACF > or = 3), whereas the formation of ACF, expressed as the number of ACF, was apparently not altered. In animals treated with AOM alone, maximal growth enhancing effect on ACF was nearly obtained with the median level of dietary polyamine. In rats fed a low polyamine diet, basic AIN-76A, DFMO reduced the growth of AOM-induced ACF by 83%. This inhibitory effect of DFMO was counteracted by dietary polyamines in a dose- dependent manner, and it was abolished at the highest level of polyamines. In conclusion, it was demonstrated that dietary polyamines are able to enhance the growth of AOM-induced ACF. Further, dietary polyamines reversed the DFMO-caused inhibition of ACF growth, probably by compensating for the DFMO-reduced endogenous polyamine synthesis.      

Comparative analysis of hepatitis C virus core protein in the plasma and serum samples from HCV-infected blood donors and patients with hepatitis C

The aim of the study was to develop a sensitive and specific method for revealing the direct marker of hepatitis C virus (HCV)--core protein in the serum and to test it in the laboratory setting. Experiments were made on plasma and serum samples from asymptomatic HCV-seropositive blood donors (n=65), patients with acute (AHC) and chronic (CHC) hepatitis C (n=295), and HCV-seronegative blood donors (n=20). The processing protocol for serum included their concentration by means of polyethylene glycol and subsequent treatments of pellets to detect core protein in free virions, nonenveloped nucleocapsids, and immune complexes. This allowed an assay to be developed for the detection of core protein, by using a sandwich ELISA. Inclusion of a combination of three original monoclonal antibodies into the sandwich could reveal in the samples core proteins of at least 3 genotypes of HCV (1, 2, and 3) with a sensitivity of 20 pg/ml in the majority of HCV-infected subjects. The results of determination of core protein and HCV RNA correlated with a high degree of sensitivity. To detect HCV in the blood of patients with AHC, it was shown to be sufficient to find freely circulating virions whereas an analysis of immune complexes should be included in cases of CHC to achieve more sensitivity. The findings are a basis for developing a test system for the diagnosis of hepatitis C, including its early stages before seroconversion and for determining a viral load during interferon therapy. Introduction of the method into practice increases the reliability of the diagnosis of hepatitis C and virus-free safety of blood transfusions.     

The role of hepatitis C virus RNA detection in various substrates of patients with chronic hepatitis C

Puncture biopsy of the liver and blood count were made in 72 patients with chronic hepatitis C (CHC). Morphological alterations in the liver were assessed by Knodell index. The blood serum, lymphocytes and hepatic tissue were examined for a genome form of hepatitis C virus (HCV) RNA, blood lymphocytes and hepatic tissue--for a relevant replication form. HCV RNA was detected using "nested" RT-PCR. Only 26% patients had symptoms of asthenovegetative and dyspeptic syndromes. Normal alaninaminotransferase (ALT) level was observed in 24% patients, the rest had it high. HCV RNA was encounted more frequently in hepatic tissue than lymphocytes or serum (83, 68 and 46%, respectively). A replication form of HCV RNA was present in hepatic tissue of 31% patients and was absent in the lymphocytes. The incidence of the RNA detection was not related either to the disease symptoms or morphological alterations in hepatic tissue. The occurrence of the genome and replication forms in hepatic tissue does not correlate to ALT level. HCV RNA occurs more often in the serum, blood lymphocytes and in three substrates simultaneously in patients with hyperalatemia.     

Antibody-binding epitope differences in the nucleoprotein of avian and mammalian influenza A viruses

Abstract Influenza virus nucleoprotein (NP) binds to the viral genome RNA and forms the internal ribonucleoprotein complex of the virus particle. Avian and human influenza virus NP have characteristic differences at several amino acid positions. It is not known whether any of these differences can be recognized by antibodies. In the present study five monoclonal antibodies (MAbs) were produced against NP of A/Duck/Novosibirsk/56/05 (H5N1) influenza virus. Two MAbs discerned human and avian influenza strains on ELISA testing. The NP expressed in a prokaryotic system was used for the analysis of site-specific mutants carrying amino acid substitutions in the relevant positions. Amino acid residues in positions 100 and 101 were shown to be recognized by the MAbs. The residue in position 100 is host-specific, and its recognition by the MAb 2E6 may be useful for the differentiation of human and avian viruses. The data are discussed in view of the effects of amino acid substitutions in influenza virus NP affecting both host range and antibody-binding specificity.     

Combined use of reminyl (galanthamine) and ovestin (oestradiol) for the treatment of cognitive disorders in women with hypoestrogenic syndrome

The efficacy of a combined therapy with reminyl and ovestin in low doses used for pharmacocorrection of cognitive disorders in women after total ovariectomy has been studied. The results show a pronounced efficacy of the proposed combined therapy as compared to the standard hormonal replacement therapy in women with hypoestrogenic syndrome, which is confirmed by a significant decrease in the expression of mental impairments evaluated using the BCRS, CCSE, and MMSE methods.     

The successful immune response against hepatitis C nonstructural protein 5A (NS5A) requires heterologous DNA/protein immunization

The aim of this study was to evaluate the immunogenicity of NS5A protein of human hepatitis C virus (HCV) when delivered as naked DNA (NS5A DNA), or recombinant protein (rNS5A). DBA/2J mice received NS5A DNA, rNS5A, or NS5A DNA/rNS5A in different prime-boost combinations with a peptidoglycan Immunomax^®. The weakest response was induced after rNS5A prime and NS5A DNA boost; rNS5A alone induced an immune response with a strong Th2-component; and NS5A DNA alone, a relatively weak secretion of IL-2 and IFN-γ. The most efficient was co-injection of NS5A DNA and rNS5A, which induced a significant increase in CD4⁺ and CD8⁺ T-cell counts, anti-NS5A antibodies, specific T-cell proliferation, and proinflammatory cytokine production in vitro against a broad spectrum of NS5A epitopes. Administration of the mixture of adjuvanted DNA and protein immunogens can be selected as the best regimen for further preclinical HCV-vaccine trials.     

Specific monoamine exchange in the brains of young and aged male rats with hypothyroidism

We analyzed monoamine exchange in different brain structures of young (2-month-old) and aged (22–24 month-old) male rats under conditions of thyroid hormone (TH) deficit or 14-day-long intraperitoneal (T₃) administration of triiodothyronine at a dose of 70 μg/kg. The contents of monoamines and their metabolites were assayed using HPLC with an electrochemical detector. In the brain structures directly related to animal behavior a TH deficit resulted in changes in monoamines, which depended on the ages of the rats. During experimental hypothyroidism, the most substantial changes in the contents and turnover of norepinephrine, dopamine, and serotonin were observed in the brains of young male rats. In aged animals, a TH deficit increased impairments in neurotransmitter exchange. Substitutive T₃ administration did not improve monoamine exchange in the brain structures of young male rats with hypothyroidism. In the aged rats with hypothyroidism, T₃ administration restored monoamine exchange only in the hippocampus but not in other brain structures.     

Evasin‐3‐like anti‐chemokine activity in salivary gland extracts of ixodid ticks during blood‐feeding: a new target for tick control

Ticks exploit many evasion mechanisms to circumvent the immune control of their hosts including subversion of the communication language between cells of the immune system provided by chemokines and other cytokines. One subversive molecule secreted in the saliva of Rhipicephalus sanguineus is Evasin‐3, a structurally unique 7 kDa protein that selectively binds the neutrophil chemoattractants, CXCL8 and (with lower affinity) CXCL1. We compared anti‐human CXCL8 and anti‐mouse CXCL1/KC activities in salivary gland extracts prepared from adult Amblyomma variegatum, Rhipicephalus appendiculatus and Dermacentor reticulatus ticks during blood‐feeding. Both anti‐CXCL8 activity and anti‐CXCL1 activity were detected in all species and in both adult females and males, with consistently higher activity levels against CXCL8. These results suggest that Evasin‐3‐like activity is common amongst metastriate ixodid tick species, and provide further evidence of the importance to ticks in controlling neutrophils during blood‐feeding. As such, Evasin‐3 offers a new target for anti‐tick vaccine development.