Hemagglutinating and fusogenic activities of Newcastle disease virus: studies on receptor binding specificity and pH-induced conformational changes

Vaccinal and wild strains of Newcastle Disease virus (NDV) were analyzed for cell receptor binding and fusogenic biological properties associated with their HN (hemagglutinin-neuraminidase) and F (fusion protein) surface structures respectively. The evaluation of the biological activities of HN and F was carried out respectively by determination of hemagglutinating titers and hemolysis percentages, using erythrocytes from various animal origins at different pH values. Significant differences in hemagglutination titers for some strains of NDV were detected, when interacting with goose, sheep, guinea-pip and human "O" group erythrocytes at neutral pH. Diversity of hemolysis percentagens was observed between different NDV strains at acid pH. These analysis were developed to evaluate particular aspects of the actual influence of the receptor specifity and pH on the receptor binding and fusogenic processes of Newcastle Disease viruses.

AA-amyloidosis caused by visceral leishmaniasis in a human immunodeficiency virus-infected patient.

AA-amyloidosis in the setting of chronic visceral leishmaniasis (VL) has been reported in animal models but documentation in humans is unavailable. Here, we report on a Portuguese man who in 1996 was diagnosed with both human immunodeficiency virus (HIV)-infection and VL. Antiretroviral treatment led to sustained suppression of HIV viremia but CD4+ lymphocytes rose from 8 to only 160 cells/mL. Several courses of antimony treatment did not prevent VL relapses. Renal failure developed in 2006 and renal biopsy revealed AA-amyloidosis. The patient had cryoglobulinemia and serum immune complexes containing antibodies directed against seven leishmanial antigens. Antimony plus amphotericin B, followed by oral miltefosine resulted in a sustained VL treatment response with elimination of circulating Leishmania infantum DNA and CD4+ recovery. The concomitant reduction of serum AA levels and disappearance of circulating leishmanial immune complexes suggests that prolonged VL may lead to AA-amyloidosis in immunocompromised humans.

An erythrocytic virus of the brazilian tree-frog, Phrynohyas venulosa

Blood erythrocytes of Brazilian tree-frogs, Phrynohyas venulosa were found to frequently contain single, small, densely staining inclusions. Electron microscopy showed these to be icosahedral viral particles which measured from 250-280 nm in diameter; they were devoid of an envelope, and thus differed from previously described viruses of frog erythrocytes. The infected erythrocytes lacked a crystalline body.

Estudi d'adipoquines com a marcadors plasmàtics de síndrome metabòlica

La síndrome metabòlica s’associa amb un risc elevat de desenvolupar diabetis tipus 2 i malaltia cardiovascular. La síndrome metabòlica es defineix com un clúster d’anormalitats metabòliques i, d’entre totes, l’obesitat abdominal constitueix el factor de risc més prevalent i crític en el desenvolupament de la síndrome metabòlica, el risc cardiovascular augmentat i la resistència a la insulina. La prevalença augmentada de l’obesitat en la població a nivell mundial ha portat el teixit adipós al primer pla dels estudis epidemiològics. Anteriorment es considerava el reservori energètic de l’organisme, actualment es parla del teixit adipós com un òrgan endocrí, metabòlicament molt actiu, implicat en diferents vies i processos metabòlics. L’etiologia de l’obesitat és complexa i multifactorial, però es fa evident en la disfuncionalitat del teixit adipós. Un teixit adipós disfuncional veu superada la seva capacitat d’emmagatzemar lípid i respon amb la hipersecreció de diferents molècules (adipoquines, citoquines i mediadors inflamatoris) a favor de la resistència a la insulina, proinflamatòries i proaterogèniques. La fatty acid-binding protein 4 (FABP4) i la retinol-binding protein 4 (RBP4) són dues adipoquines que en circulació, es desconeix la funció exacta que duen a terme. Estudis recents han suggerit la FABP4 com a marcador d’adipositat, síndrome metabòlica i diabetis tipus 2. I, RBP4, malgrat que les dades de diferents estudis en humans desperten certa controvèrsia, s’ha associat amb la resistència a la insulina i el desenvolupament de la diabetis tipus 2. En aquesta memòria es recullen els treballs en què es va estudiar el paper d’aquestes adipoquines en relació a malalties de base metabòlica amb afectació del teixit adipós com són la síndrome metabòlica, la diabetis tipus 2, la hiperlipèmia familiar combinada i la, lipodistrofia associada a tractament combinat antiretroviral de la infecció pel virus de la immunodeficiència humana (VIH).

Les comportements face au VIH/sida des hommes qui ont des relations sexuelles avec des hommes: résultats de Gaysurvey 2007

Gaysurvey est une enquête menée périodiquement en Suisse parmi les hommes qui ont des relations sexuelles avec des hommes (HSH). Elle s'inscrit dans le dispositif de surveillance du VIH, établi par l'Office fédéral de la santé publique, en tant qu'instrument de suivi des comportements face au VIH/sida dans ce groupe-cible. Elle a déjà été réalisée à huit reprises : en 1987, 1990, 1992, 1994, 1997, 2000, 2004, 2007. [...] Elle permet d'établir des tendances temporelles au niveau des pratiques sexuelles et des expositions au risque d'infection par le VIH. Elle permet, en outre, d'approfondir certaines thématiques pertinentes pour le travail de prévention (gestion du risque au sein d'une relation stable, entrée dans la sexualité, etc.). Ce document a pour objectif de faire la synthèse des tendances mises au jour lors de la dernière vague d'enquête, réalisée en 2007. [Introduction p. 4]

Individual contributions of mutant protease and reverse transcriptase to viral infectivity, replication, and protein maturation of antiretroviral drug-resistant human immunodeficiency virus type 1.

Human immunodeficiency virus type 1 (HIV-1) variants resistant to protease (PR) and reverse transcriptase (RT) inhibitors may display impaired infectivity and replication capacity. The individual contributions of mutated HIV-1 PR and RT to infectivity, replication, RT activity, and protein maturation (herein referred to as "fitness") in recombinant viruses were investigated by separately cloning PR, RT, and PR-RT cassettes from drug-resistant mutant viral isolates into the wild-type NL4-3 background. Both mutant PR and RT contributed to measurable deficits in fitness of viral constructs. In peripheral blood mononuclear cells, replication rates (means +/- standard deviations) of RT recombinants were 72.5% +/- 27.3% and replication rates of PR recombinants were 60.5% +/- 33.6% of the rates of NL4-3. PR mutant deficits were enhanced in CEM T cells, with relative replication rates of PR recombinants decreasing to 15.8% +/- 23.5% of NL4-3 replication rates. Cloning of the cognate RT improved fitness of some PR mutant clones. For a multidrug-resistant virus transmitted through sexual contact, RT constructs displayed a marked infectivity and replication deficit and diminished packaging of Pol proteins (RT content in virions diminished by 56.3% +/- 10.7%, and integrase content diminished by 23.3% +/- 18.4%), a novel mechanism for a decreased-fitness phenotype. Despite the identified impairment of recombinant clones, fitness of two of the three drug-resistant isolates was comparable to that of wild-type, susceptible viruses, suggestive of extensive compensation by genomic regions away from PR and RT. Only limited reversion of mutated positions to wild-type amino acids was observed for the native isolates over 100 viral replication cycles in the absence of drug selective pressure. These data underscore the complex relationship between PR and RT adaptive changes and viral evolution in antiretroviral drug-resistant HIV-1.

Dried blood spots collected on filter paper: an international resource for the diagnosis and genetic characterization of human immunodeficiency virus Type-1

The collection of dried blood spots (DBS) on filter paper provides a powerful approach for the development of large-scale, population-based screening programs. DBS methods are particularly valuable in developing countries and isolated rural regions where resources are limited. Large numbers of field specimens can be economically collected and shipped to centralized reference laboratories for genetic and (or) serological analysis. Alternatively, the dried blood can be stored and used as an archival resource to rapidly establish the frequency and distribution of newly recognized mutations, confirm patient identity or track the origins and emergence of newly identified pathogens. In this report, we describe how PCR-based technologies are beginning to interface with international screening programmes for the diagnosis and genetic characterization of human immunodeficiency virus type 1 (HIV-1). In particular, we review recent progress using DBS specimens to resolve the HIV-1 infection status of neonates, monitor the genetic evolution of HIV-1 during early infancy and establish a sentinel surveillance system for the systematic monitoring of HIV-1 genetic variation in Asia.

Aspectes de l'adquisició de la quantificació en català

Aquest estudi té dos objectius principals. Per una banda, vol contribuir a la caracterització de l'adquisició dels quantificadors en llengua catalana i, per l'altra, pretén comprovar si hi ha diferències en l'adquisició dels quantificadors universals tots i cada entre els infants amb un desenvolupament típic i els infants amb trastorn específic del llenguatge

Biological characterization of clones derived from the edmonston strain of measles virus in comparison with schwarz and CAM-70 vaccine strains

Four virus clones were derived from the Edmonston strain of measles virus by repeated plaque purification. These clones were compared with the vaccine strains Schwarz and CAM-70 in terms of biological activities including plaque formation, hemagglutination, hemolysis and replication in Vero cells and chick embryo fibroblasts (CEF). Two clones of intermediate plaque yielded mixed plaque populations on subcultivation whereas the other two, showing small and large plaque sizes, showed stable plaque phenotypes. The vaccine strains showed consistent homogeneous plaque populations. All the Edmonston clones showed agglutination of monkey erythrocytes in isotonic solution while both vaccine strains hemagglutinated only in the presence of high salt concentrations. Variation in the hemolytic activity was observed among the four clones but no hemolytic activity was detected for the vaccine virus strains. Vaccine strains replicated efficiently both in Vero cells and CEF. All four clones showed efficient replication in Vero cells but different replication profiles in CEF. Two of them replicated efficiently, one was of intermediate efficiency and the other showed no replication in CEF. Two of the clones showed characteristics similar to vaccine strains. One in terms of size and homogeneity of plaques, the other for a low hemolytic activity and both for the efficiency of propagation in CEF.

Rabies virus infection of cultured adult mouse dorsal root ganglion neurons

An in vitro model of adult dorsal root ganglion neurons infection by rabies virus is described. Viral marked neurotropism is observed, and the percentage and the degree of infection of the neurons is higher than in non neuronal cells, even if neurons are the minority of the cells in the culture. The neuritic tree is also heavily infected by the virus.

Tuberculin Skin Test and CD4+/CD8+ T Cell Counts in Adults Infected with the Human Immunodeficiency Virus in Medellín, Colombia

To evaluate the effect of BCG vaccination and T lymphocyte subpopulations on the reactivity to the tuberculin skin test, 113 asymtomatic HIV+ individuals were tuberculin tested by intradermal injection of 5TU of purified protein derivative and the levels of circulating lymphocyte (CD3, CD4 and CD8) subpopulations determined by indirect immunofluorescence. Ninety-two percent of the subjects included in the study were males. The mean age of the group was 32.1±7.4 years. Sixty-two percent presented a BCG scar. However, only 22% exhibited positive tuberculin reactions (³5mm) irrespective of the presence of the BCG scar. Tuberculin positive individuals exhibited higher CD4+ cell counts (p=0.004) and CD4+/CD8+ ratios (p=0.006) than tuberculin negative (<5mm) HIV+ individuals. The number of individuals with positive tuberculin reactions was significantly higher in subjects with more than 500 CD4+ lymphocytes/ml (p=0.02) or CD4+/CD8+ ratios ³1.12 (p=0.002). These results suggest that a prior BCG vaccination does not influence the reactivity to the tuberculin skin test in HIV+ asymptomatic individuals and that the number of CD4+ lymphocytes and the CD4+/CD8+ ratio positively correlate with the tuberculin reactivity