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Search Results: 1 - 10 of 261042 matches for " André Luiz R. Roque "
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Maintenance and breeding of Thrichomys (Trouessart, 1880) (Rodentia: Echimyidae) in captivity
Teixeira, Bernardo Rodrigues;Roque, André Luiz R;Barreiros-Gómez, Simone Cristina;Borodin, Pavel Mikhailovitch;Jansen, Ana Maria;D'Andrea, Paulo Sérgio;
Memórias do Instituto Oswaldo Cruz , 2005, DOI: 10.1590/S0074-02762005000600005
Abstract: south american histricognath rodents thrichomys apereoides laurentius and thrichomys pachyurus are natural hosts of trypanosoma cruzi, agent of chagas disease. we established breeding colonies of these species to serve as experimental models in various parasitological studies. both species of thrichomys have all the requirements necessary to become excellent laboratory models: they can be easily maintained in the standard laboratory conditions and breed throughout the year and they do not have any special dietary demands and can be fed by standard food pellets designed for laboratory mice. both species produce precocious offspring that have their eyes and ears open, teeth erupted, fur well developed, and can eat solid food in the first week of life. t. a. laurentius has larger litter sizes and lower body masses at birth and weaning than t. pachyurus. moreover, females of t. a. laurentius reach puberty earlier and with lower body mass than t. pachyurus.
Distinct Leishmania Species Infecting Wild Caviomorph Rodents (Rodentia: Hystricognathi) from Brazil
Renata Cássia-Pires,Mariana C. Boité,Paulo S. D'Andrea,Heitor M. Herrera,Elisa Cupolillo,Ana Maria Jansen,André Luiz R. Roque
PLOS Neglected Tropical Diseases , 2014, DOI: 10.1371/journal.pntd.0003389
Abstract: Background Caviomorph rodents, some of the oldest Leishmania spp. hosts, are widely dispersed in Brazil. Despite both experimental and field studies having suggested that these rodents are potential reservoirs of Leishmania parasites, not more than 88 specimens were analyzed in the few studies of natural infection. Our hypothesis was that caviomorph rodents are inserted in the transmission cycles of Leishmania in different regions, more so than is currently recognized. Methodology We investigated the Leishmania infection in spleen fragments of 373 caviomorph rodents from 20 different species collected in five Brazilian biomes in a period of 13 years. PCR reactions targeting kDNA of Leishmania sp. were used to diagnose infection, while Leishmania species identification was performed by DNA sequencing of the amplified products obtained in the HSP70 (234) targeting. Serology by IFAT was performed on the available serum of these rodents. Principal findings In 13 caviomorph rodents, DNA sequencing analyses allowed the identification of 4 species of the subgenus L. (Viannia): L. shawi, L. guyanensis, L. naiffi, and L. braziliensis; and 1 species of the subgenus L. (Leishmania): L. infantum. These include the description of parasite species in areas not previously included in their known distribution: L. shawi in Thrichomys inermis from Northeastern Brazil and L. naiffi in T. fosteri from Western Brazil. From the four other positive rodents, two were positive for HSP70 (234) targeting but did not generate sequences that enabled the species identification, and another two were positive only in kDNA targeting. Conclusions/Significance The infection rate demonstrated by the serology (51.3%) points out that the natural Leishmania infection in caviomorph rodents is much higher than that observed in the molecular diagnosis (4.6%), highlighting that, in terms of the host species responsible for maintaining Leishmania species in the wild, our current knowledge represents only the “tip of the iceberg.”
Characterization of PbPga1, an Antigenic GPI-Protein in the Pathogenic Fungus Paracoccidioides brasiliensis
Clarissa X. R. Valim, Luiz Roberto Basso, Fausto B. dos Reis Almeida, Thaila Fernanda Reis, André Ricardo Lima Damásio, Luisa Karla Arruda, Roberto Martinez, Maria Cristina Roque-Barreira, Constance Oliver, Maria Célia Jamur, Paulo Sergio Rodrigues Coelho
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0044792
Abstract: Paracoccidioides brasiliensis is the etiologic agent of paracoccidioidomycosis (PCM), one of the most prevalent mycosis in Latin America. P. brasiliensis cell wall components interact with host cells and influence the pathogenesis of PCM. Cell wall components, such as glycosylphosphatidylinositol (GPI)-proteins play a critical role in cell adhesion and host tissue invasion. Although the importance of GPI-proteins in the pathogenesis of other medically important fungi is recognized, little is known about their function in P. brasiliensis cells and PCM pathogenesis. We cloned the PbPga1 gene that codifies for a predicted GPI-anchored glycoprotein from the dimorphic pathogenic fungus P. brasiliensis. PbPga1 is conserved in Eurotiomycetes fungi and encodes for a protein with potential glycosylation sites in a serine/threonine-rich region, a signal peptide and a putative glycosylphosphatidylinositol attachment signal sequence. Specific chicken anti-rPbPga1 antibody localized PbPga1 on the yeast cell surface at the septum between the mother cell and the bud with stronger staining of the bud. The exposure of murine peritoneal macrophages to rPbPga1 induces TNF-α release and nitric oxide (NO) production by macrophages. Furthermore, the presence of O-glycosylation sites was demonstrated by β-elimination under ammonium hydroxide treatment of rPbPga1. Finally, sera from PCM patients recognized rPbPga1 by Western blotting indicating the presence of specific antibodies against rPbPga1. In conclusion, our findings suggest that the PbPga1gene codifies for a cell surface glycoprotein, probably attached to a GPI-anchor, which may play a role in P. brasiliensis cell wall morphogenesis and infection. The induction of inflammatory mediators released by rPbPga1 and the reactivity of PCM patient sera toward rPbPga1 imply that the protein favors the innate mechanisms of defense and induces humoral immunity during P. brasiliensis infection.
Produ??o de lodo e comportamento químico de sais de ferro empregados no pós-tratamento de esgoto sanitário por precipita??o química
Ferreira Filho, Sidney Seckler;Marguti, André Luiz;Piveli, Roque Passos;
Engenharia Sanitaria e Ambiental , 2009, DOI: 10.1590/S1413-41522009000100006
Abstract: the combination of physical-chemical and biological processes in sanitary wastewater treatment has been employed as an alternative for phosphorus removal; however, one of its limitations is its large sludge production. this work aimed at evaluating the sludge production which resulted from iron salt application to different types of effluents, as well as studying the impacts of iron salt application on the physical-chemical characteristics of the studied effluents. it was concluded that the average sludge production values which resulted from ferric hydroxide formation were around 1.80, 1.95 and 1.34 mg sludge per mg of fe+3 ion, with regard to raw wastewater, aerobic treated effluent and anaerobic treated effluent, respectively, thus indicating that the liquid phase characteristics did not influence the ferric ion precipitation mechanisms.
Otimiza??o de processos físico-químicos na remo??o de fósforo de esgotos sanitários por processos de precipita??o química com cloreto férrico
Marguti, André Luiz;Ferreira Filho, Sidney Seckler;Piveli, Roque Passos;
Engenharia Sanitaria e Ambiental , 2008, DOI: 10.1590/S1413-41522008000400008
Abstract: since chemical coagulation processes are very promising for wastewater treatment, this work looked into phosphorus removal from aerobic and anaerobic systems treating domestic wastewater. it was possible to reach phosphorus removal efficiencies in the order of 90 % for coagulant dosages in the range 60 to 100 mg of ferric chloride per liter. dissolved organic carbon (doc) removal in parallel with phosphorus removal was observed for the previously mentioned treatment system effluents. the coagulant dosages for optimized phosphorus removal also led to optimum doc removal. the removal of organic phosphorus fractions as polyphosphates was justified due its association with the doc removal by chemical precipitation.
Thrichomys laurentius (Rodentia; Echimyidae) as a Putative Reservoir of Leishmania infantum and L. braziliensis: Patterns of Experimental Infection
André Luiz Rodrigues Roque,Elisa Cupolillo,Renato Sergio Marchevsky,Ana Maria Jansen
PLOS Neglected Tropical Diseases , 2010, DOI: 10.1371/journal.pntd.0000589
Abstract: The importance of the genus Thrichomys in the retention of infection and transmission of Leishmania species is supported by previous studies that describe an ancient interaction between caviomorphs and trypanosomatids and report the natural infection of Thrichomys spp. Moreover, these rodents are widely dispersed in Brazil and recognized as important hosts of other tripanosomatids. Our main purpose was to evaluate the putative role of Thrichomys laurentius in the retention of infection and amplification of the transmission cycle of Leishmania infantum and L. braziliensis. Male and female T. laurentius (n = 24) born in captivity were evaluated for the retention of infection with these Leishmania species and followed up by parasitological, serological, hematological, biochemical, histological, and molecular assays for 3, 6, 9, or 12 months post infection (mpi). T. laurentius showed its competence as maintenance host for the two inoculated Leishmania species. Four aspects should be highlighted: (i) re-isolation of parasites 12 mpi; (ii) the low parasitic burden displayed by T. laurentius tissues; (iii) the early onset and maintenance of humoral response, and (iv) the similar pattern of infection by the two Leishmania species. Both Leishmania species demonstrated the ability to invade and maintain itself in viscera and skin of T. laurentius, and no rodent displayed any lesion, histological changes, or clinical evidence of infection. We also wish to point out the irrelevance of the adjective dermotropic or viscerotropic to qualify L. braziliensis and L. infantum, respectively, when these species are hosted by nonhuman hosts. Our data suggest that T. laurentius may act at least as a maintenance host of both tested Leishmania species since it maintained long-lasting infections. Moreover, it cannot be discarded that Leishmania spp. infection in free-ranging T. laurentius could result in higher parasite burden due the more stressing conditions in the wild. Therefore the tissular parasitism of the skin, infectiveness to the vector, and amplification of the transmission cycle of both Leishmania species could be expected.
Determination of ranitidine in drugs using a mercury coated platinum ultramicroelectrode and hanging mercury dropping electrode
Malagutti, Andréa R.;Mazo, Luiz H.;
Journal of the Brazilian Chemical Society , 2003, DOI: 10.1590/S0103-50532003000200015
Abstract: the voltammetric behavior of ranitidine has been studied in aqueous media with a mercury coated platinum ultramicroelectrode (hg-ume) and by hmde. the lsv curves for the electroreduction of ranitidine showed that the compound presents two reduction waves in ph < 4.0 and only one in ph > 4.0, the observed waves being attributed to the reduction of the nitro group to hydroxylamine. a linear relation between the current peak or limiting current and the ranitidine concentration using hmde or hg-ume was observed, demonstrating that these ultramicroelectrodes can be used in the analytical determination of ranitidine. an alternative and more sensitive methodology for the analytical determination of ranitidine by swv was also developed, with a detection limit of 3.5 x 10-8 mol l-1 (or 11 mg l-1). the apparent recovery (ar) studies proved the accuracy and precision of the assay developed. the excipients found in comercial antak tablets (glaxo wellcome) and the generic from emsa do not interfere in the determination.
Intercompara??o entre quatro métodos de estimativa da altura da camada limite convectiva durante o experimento RaCCI - LBA (2002) em Rond?nia - Amaz?nia
Santos, Luiz André R. dos;Fisch, Gilberto;
Revista Brasileira de Meteorologia , 2007, DOI: 10.1590/S0102-77862007000300005
Abstract: this work has like objective to do a comparison between four different methods of estimate of the convective boundary layer (cbl) height, utilizing data obtained by the sodar and radiossound, during the dry - to - wet campaign of the racci - lba experiment in rondonia, (2002). the four methods of estimate utilized were: the parcel method; the richardson number method; the profiles method; and a direct measurement method by sodar. the results showed that the parcel method overestimated the heights of the cbl (15% at 08:00 lt and 14:00 lt, and 30% to the other hours), in most of cases analyzed, obtaining a short determination index (r2), when compared with the others methods. the richardson number method and the profiles method presented very similar heights, with average differences less than 50 m, achieving a r2 value about 0,97, during the beginning of the rainy station. the sodar data was not adequate at the first hours of the morning, showing that the equipment takes the residual boundary layer (from the previous day) and not the shallow convective boundary layer, in development.
Determination of ranitidine in drugs using a mercury coated platinum ultramicroelectrode and hanging mercury dropping electrode
Malagutti Andréa R.,Mazo Luiz H.
Journal of the Brazilian Chemical Society , 2003,
Abstract: The voltammetric behavior of ranitidine has been studied in aqueous media with a mercury coated platinum ultramicroelectrode (Hg-UME) and by HMDE. The LSV curves for the electroreduction of ranitidine showed that the compound presents two reduction waves in pH < 4.0 and only one in pH > 4.0, the observed waves being attributed to the reduction of the nitro group to hydroxylamine. A linear relation between the current peak or limiting current and the ranitidine concentration using HMDE or Hg-UME was observed, demonstrating that these ultramicroelectrodes can be used in the analytical determination of ranitidine. An alternative and more sensitive methodology for the analytical determination of ranitidine by SWV was also developed, with a detection limit of 3.5 x 10-8 mol L-1 (or 11 mug L-1). The apparent recovery (AR) studies proved the accuracy and precision of the assay developed. The excipients found in comercial Antak tablets (Glaxo Wellcome) and the generic from EMSa do not interfere in the determination.
PAR METROS METABóLICOS SANGUíNEOS DE VACAS LEITEIRAS DE ALTA PRODU O NO PERíODO DE TRANSI O
Tiago André Frigotto,Rüdiger Daniel Ollhoff,Ivan Roque de Barros Filho,Rodrigo de Almeida
Ciência Animal Brasileira , 2009,
Abstract:
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