Genetic and biologic observations suggest that pigs may serve as “mixing vessels” for the generation of human-avian influenza A virus reassortants, similar to those responsible for the 1957 and 1968 pandemics. Here we demonstrate a structural basis for this hypothesis. Cell surface receptors for both human and avian influenza viruses were identified in the pig trachea, providing a milieu conducive to viral replication and genetic reassortment. Surprisingly, with continued replication, some avian-like swine viruses acquired the ability to recognize human virus receptors, raising the possibility of their direct transmission to human populations. These findings help to explain the emergence of pandemic influenza viruses and support the need for continued surveillance of swine for viruses carrying avian virus genes.

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These results suggested that the use of homeopathic medicines minimized the number of flu and acute respiratory infection symptomatic episodes in children, signalizing that the homeopathic prophylactic potential should be investigated in further studies.

Sialic acids from sialoglycoconjugates present at the cell surface of Cryptococcus neoformans yeast forms were analyzed by high-performance thin-layer chromatography, binding of influenza A and C virus strains, enzymatic treatment, and flow cytofluorimetry with fluorescein isothiocyanate-labeled lectins. C. neoformans yeast forms grown in a chemically defined medium contain N-acetylneuraminic acid and its 9-O-acetylated derivative. A density of 3 ؋ 10 6 residues of sialic acid per cell was found in C. neoformans. Sialic acids in cryptococcal cells are glycosidically linked to galactopyranosyl units as inferred from the increased reactivity of neuraminidase-treated yeasts with peanut agglutinin. N-Acetylneuraminic acids are ␣-2,6 and ␣-2,3 linked, as indicated by using virus strains M1/5 and M1/5 HS8, respectively, as agglutination probes. The ␣-2,6 linkage markedly predominated. These findings were essentially confirmed by the interaction of cryptococcal cells with the lectins Sambucus nigra agglutinin and Maackia amurensis agglutinin. We also investigated whether the sialyl residues present in C. neoformans are involved in the fungal interaction with a cationic solid-phase substrate and with mouse resident macrophages. Adhesion of yeast cells to poly-L-lysine was mediated, in part, by sialic acid residues, since the number of adherent cells was markedly reduced after treatment with bacterial neuraminidase. The enzymatic removal of sialic acids also made C. neoformans yeast cells more susceptible to endocytosis by macrophages. The results show that sialic acids are components of the cryptococcal cell surface that contribute to its negative charge and protect yeast forms against phagocytosis.

Influenzinum RC altered cellular and biochemical features of MDCK and J774G8 cells.

Five extracts from A . brasilianu, obtained through different procedures, showed anti-HSV activity. The best activity was detected in a fraction (B) that was obtained from the crude cold aqueous extract on Sephadex GIs. Fraction B showed low cellular toxicity and inhibition from 32.4% to 99.9% at concentrations from 6.2 to 50.0 pg/mL, exhibiting a therapeutic index of 32. Fractions obtained on Sephadex Glm and reversed-phase column also showed considerable inhibition. Fraction B did not show any virucidal activity, however, its inhibitory activity was revealed during the later stages of the virus replication cycle. This fraction showed activity on DNA synthesis of infected cells.

The circulation of influenza C viruses in Rio de Janeiro, Brazil, was studied when significant levels of antibodies were detected (56.7%) with hemagglutination inhibition test, used as a standard methodology for influenza virus studies.

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