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Dive into the research topics where Joao Roberto Braga de Mello is active.

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Featured researches published by Joao Roberto Braga de Mello.


Toxicon | 2003

Calcinosis--calcinogenic plants.

Joao Roberto Braga de Mello

The calcinogenic plants are among the most noxious plants to animals in the world. The pathological and biochemical effects of calcinogenic plants in cattle, sheep, goats, pigs, horses, buffalo and laboratory animals have been determined. The chemical nature of the toxic agents and the precise mechanism by with the calcinogenic plants induces calcinosis have been defined. Most of the active principle present as steroidal glycoside is hydrolyzed in intestine, rumen and other tissues or by the bacterial flora releasing the steroidal fragment, in most cases 1,25(OH)(2)D(3). The excess of vitamin D stimulates CaBP synthesis and calcium and phosphate absorption, producing hypercalcemia and/or hyperphosphatemia. The excessively absorbed mineral cannot be physiologically accommodated, and the deposition in soft tissues results in calcinosis. The different means of treatment of calcinosis and control of calcinogenic plants are discussed with regards to their effectiveness. A number of potential uses of calcinogenic plants have been suggested but none has been exploited on a large scale. The understanding of the mechanisms involved with calcinosis contributed enormously to the compression of vitamin D mechanism. Research methods were developed and improved but a lot is to be done in this fascinating subject.


Brazilian Journal of Microbiology | 2010

In vitro activity of Origanum vulgare essential oil against Candida species

Marlete Brum Cleff; Melissa Orzechowski Xavier; Luiz Filipe Damé Schuch; Mário Carlos Araújo Meireles; Maria Regina Alves Rodrigues; Joao Roberto Braga de Mello

The aim of this study was to evaluate the in vitro activity of the essential oil extracted from Origanum vulgare against sixteen Candida species isolates. Standard strains tested comprised C. albicans (ATCC strains 44858, 4053, 18804 and 3691), C. parapsilosis (ATCC 22019), C. krusei (ATCC 34135), C. lusitaniae (ATCC 34449) and C. dubliniensis (ATCC MY646). Six Candida albicans isolates from the vaginal mucous membrane of female dogs, one isolate from the cutaneous tegument of a dog and one isolate of a capuchin monkey were tested in parallel. A broth microdilution technique (CLSI) was used, and the inoculum concentration was adjusted to 5 x 10 6 CFU mL -1 . The essential oil was obtained by hydrodistillation in a Clevenger apparatus and analyzed by gas chromatography. Susceptibility was expressed as Minimal Inhibitory Concentration (MIC) and Minimal Fungicidal Concentration (MFC). All isolates tested in vitro were sensitive to O. vulgare essential oil. The chromatographic analysis revealed that the main compounds present in the essential oil were 4-terpineol (47.95%), carvacrol (9.42%), thymol (8.42%) and �-terpineol (7.57%). C. albicans isolates obtained from animal mucous membranes exhibited MIC and MFC values of 2.72 �L mL -1 and 5 �L mL -1 , respectively. MIC and MFC values for C. albicans


Arquivo Brasileiro De Medicina Veterinaria E Zootecnia | 2008

Atividade in vitro do óleo essencial de Origanum vulgare frente à Sporothrix Schenckii

Marlete Brum Cleff; Luiz Filipe Damé Schuch; Maria Regina Alves Rodrigues; Mário Carlos Araújo Meireles; Joao Roberto Braga de Mello

In vitro activity of the essential oil Origanum vulgare against Sporothrix schenckii was determined by the MIC (Minimum Inhibitory Concentration). For this, seven samples of S. schenckii were studied, two isolated from two cases of human sporotrichosis and five isolated from cats. Analysis of the essential oil was carried out in a gas chromatograph (GC/FID) for the identification and quantification of thymol and carvacrol (antifungal agents). MIC was obtained based on the microdilution method according to the adapted document NCCLS-M 27A2 for fitopharmacy. All the isolates presented sensibility to the essential oil. S. schenckii was inhibited in a concentration of 0.25% (250m l/ml). Chromatographic analysis showed that thymol concentration was bigger than carvacrol. The antifungal activity demonstrated by the essential oil of O. vulgare against S. Schenckii stimulates the accomplishment of more studies, including in vivo studies.


Brazilian Journal of Microbiology | 2009

CLSI BROTH MICRODILUTION METHOD FOR TESTING SUSCEPTIBILITY OF MALASSEZIA PACHYDERMATIS TO THIABENDAZOLE

Patrícia da Silva Nascente; Renata Osório de Faria; Luiz Filipe Damé Schuch; Mário Carlos Araújo Meireles; Joao Roberto Braga de Mello

Thiabendazole, classified as antiparasitic and also used as an antifungal drug, can be found as otological solution indicated for treatment of parasitic and fungal external otitis in small animals. Malassezia pachydermatis is a yeast recognized as a normal inhabitant on the skin and mucous membranes of dogs and cats. However, it is considered an opportunistic agent that causes external otitis and dermatitis in these animals. The aim of this study was to evaluate the in vitro effect of thiabendazole against 51 isolates of M. pachydermatis using the CLSI Broth Microdilution method that has been adapted for this yeast species (NCCLS, 2002). Based on this test, the Minimum Inhibitory Concentrations (MIC) of thiabendazol was calculated. Subsequently, the susceptibility of each isolate against this antifungal was determined. It was observed that the MIC of thiabendazole against M. pachydermatis ranged from 0.03 to > 4 µg/mL. A total of 13.7% of the isolates were found to be resistant, 47.1% were intermediate and 39.2% were sensitive to the drug. The rate of resistance of the yeasts against thiabendazole was similar to the results previously obtained with other antifungals, while the adapted broth microdilution technique used in this study proved to be efficient.


Revista Da Sociedade Brasileira De Medicina Tropical | 2010

Ocorrência de Cryptococcus neoformans em excretas de pombos na cidade de Pelotas, Estado do Rio Grande do Sul

Renata Osório de Faria; Patrícia da Silva Nascente; Ana Raquel Mano Meinerz; Marlete Brum Cleff; Tatiana de Avila Antunes; Érica da Silva Silveira; Márcia de Oliveira Nobre; Mário Carlos Araújo Meireles; Joao Roberto Braga de Mello

INTRODUCTION Cryptococcus neoformans is an encapsulated yeast and is the etiological agent for human and animal cryptococcosis. It is found in sources within the environment, including pigeon excrement, and is an important cause of mortality among immunocompromised individuals worldwide. METHODS Seventy different environments in the city of Pelotas, Rio Grande do Sul, were surveyed for the purpose of investigating Cryptococcus neoformans occurrences in pigeon excreta. The environments included buildings, public squares and outdoor locations in the city. After collection, chloramphenicol saline solution was added to the excreta, which were then homogenized and seeded onto Sabouraud agar with chloramphenicol and onto Niger agar, and incubated at 32 degrees C. Identification was performed by direct examination and by means of the phenoloxidase and urease tests, carbohydrate assimilation and culturing in CGB medium. RESULTS Out of the sites investigated (n = 70), 26 (37.1%) of them contained pigeon excreta. These included historical buildings (n = 8), a church tower (n = 1), rice mills and warehouses (n = 7), a public square (n = 1) and outdoor locations (n = 9). Cryptococcus neoformans was isolated from 26.9% (n = 7/26) of these locations. CONCLUSIONS This study draws attention to isolation of this fungus in urban areas that present large accumulations of pigeon excrement. This represents a risk to public health, especially for immunocompromised individuals.


Pesquisa Veterinaria Brasileira | 2011

Intoxicação por Senecio spp. em bovinos no Rio Grande do Sul: condições ambientais favoráveis e medidas de controle

Fernando Sérgio Castilhos Karam; Ana Lucia Schild; Joao Roberto Braga de Mello

The study aimed to review the main aspects of Senecio spp. poisoning in Rio Grande do Sul, sou-thern Brazil, in relation to the pathology, pathogenesis and epidemiology of this important cause of death in cattle in that State. The main climatic and environmental factors that apparently favor the emersion and plant establishment were revised. The occurrence of poisoning, which has increased its frequency in recent years in the state, and possible ways to control the plant, including the correct handling of soil and the use of less susceptible domestic species in invaded areas were also discussed.


Brazilian Journal of Microbiology | 2013

Clinical and mycological analysis of dog's oral cavity

Rosema Santin; Antonella Souza Mattei; Stefanie Bressan Waller; Isabel Martins Madrid; Marlete Brum Cleff; Melissa Orzechowski Xavier; Márcia de Oliveira Nobre; Patrícia da Silva Nascente; Joao Roberto Braga de Mello; Mário Carlos Araújo Meireles

The oral microbiota of humans and animals is made up of a wide variety of yeasts and bacteria, but microbiota of dogs is not totally described. Although such identification is an important step to establish the etiopathogenesis and adequate therapy for the periodontal disease The aim of this study was to evaluate and correlate oral alterations with the presence of yeasts in oral cavity of female dogs. After clinical evaluation samples from healthy and from dogs with oral diseases were obtained from three different oral sites by swabs, curettes, millimeter periodontal probes and HA membrane tip in cellulose ester. Yeast identification was performed through macroscopic and microscopic colony features and biochemical tests. Dental calculus was the most prevalent occurrence in the oral cavity of 59 females. However, the isolation of yeasts was significantly higher (p < 0.05) in animals suffering from halitosis. Eleven yeast species were identified, namely: Malassezia pachydermatis, Rhodotorula spp., Candida albicans, C. catenulata, C. famata, C. guilliermondii, C. parapsilosis, C. intermedia, Trichosporon asahii, T. mucoides and Cryptococcus albidus. It could be concluded that the yeasts are part of the microbiota from the different sites of the oral cavity of the female canines studied without causing any significant alterations except halitosis.


Revista Do Instituto De Medicina Tropical De Sao Paulo | 2014

FUNGI ISOLATED FROM THE EXCRETA OF WILD BIRDS IN SCREENING CENTERS IN PELOTAS, RS, BRAZIL

Josiara Furtado Mendes; Ana Paula Neuschrank Albano; Marco Antônio Afonso Coimbra; G. F. Ferreira; Carolina Lambrecht Gonçalves; Patrícia da Silva Nascente; Joao Roberto Braga de Mello

The identification of the fungal species belonging to the healthy microflora in animals is a precondition for the recognition of pathological processes causing them. The aim of this study was to investigate the presence of potentially pathogenic fungi in the feces of wild birds collected in Screening Centers. Samples were collected from the feces of 50 cages with different species of birds. The samples were processed according to the modified method STAIB and the plates incubated at 32 °C for up to ten days with daily observation for detection of fungal growth. The isolation of the following species was observed: Malassezia pachydermatis, Candida albicans, C. famata, C. guilliermondii, C. sphaerica, C. globosa, C. catenulata, C. ciferri, C. intermedia, Cryptococcus laurentii, Trichosporon asahii, Geotrichum klebahnii, Aspergillus spp., A. niger and Penicillium spp. Knowing the character of some opportunistic fungi is important in identifying them, facilitating the adoption of preventive measures, such as proper cleaning of cages, since the accumulation of excreta may indicate a risk for both health professionals and centers for screening public health.


Brazilian Journal of Microbiology | 2016

Cytotoxicity and anti-Sporothrix brasiliensis activity of the Origanum majorana Linn. oil

Stefanie Bressan Waller; Isabel Martins Madrid; Vanny Ferraz; Tony Picoli; Marlete Brum Cleff; Renata Osório de Faria; Mário Carlos Araújo Meireles; Joao Roberto Braga de Mello

The study aimed to evaluate the anti-Sporothrix sp. activity of the essential oil of Origanum majorana Linn. (marjoram), its chemical analysis, and its cytotoxic activity. A total of 18 fungal isolates of Sporothrix brasiliensis (n: 17) from humans, dogs and cats, and a standard strain of Sporothrix schenckii (n: 1) were tested using the broth microdilution technique (Clinical and Laboratory Standard Institute – CLSI M27-A3) and the results were expressed in minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC). The MIC50 and MIC90 of itraconazole against S. brasiliensis were 2 μg/mL and 8 μg/mL, respectively, and the MFC50 and MFC90 were 2 μg/mL and >16 μg/mL, respectively, with three S. brasiliensis isolates resistant to antifungal. S. schenckii was sensitive at MIC of 1 μg/mL and MFC of 8 μg/mL. For the oil of O. majorana L., all isolates were susceptible to MIC of ≤2.25–9 mg/mL and MFC of ≤2.25–18 mg/mL. The MIC50 and MIC90 were ≤2.25 mg/mL and 4.5 mg/mL, respectively, and the MFC50/90 values were twice more than the MIC. Twenty-two compounds were identified by gas chromatography with a flame ionization detector (CG-FID) and 1,8-cineole and 4-terpineol were the majority. Through the colorimetric (MTT) assay, the toxicity was observed in 70–80% of VERO cells between 0.078 and 5 mg/mL. For the first time, the study demonstrated the satisfactory in vitro anti-Sporothrix sp. activity of marjoram oil and further studies are needed to ensure its safe and effective use.


Arquivo Brasileiro De Medicina Veterinaria E Zootecnia | 2010

Desenvolvimento pós-natal e potencial teratogênico da prole de ratos Wistar no estudo da toxicidade reprodutiva de duas preparações fitoterápicas contendo soja Glycine max (L.) Merr

Carlos Eduardo Bortolini; J.M. Batista; E.B. Hollenbach; Tatiana Larissa Schuch; M.H. Pacheco; Fernanda Bastos de Mello; Joao Roberto Braga de Mello

The effect of two commercial phytotherapic preparations containing soy was evaluated on the general and sexual development of Wistar rats offspring and on the teratogenic potential during a reproductive toxicity study. For this, the offspring development characteristics were daily observed, and the behavior in open field was studied. To assess the teratogenic potential, diaphanization of the fetuses removed by caesarean section was done. It was concluded that the treatment of the parents did not compromise the development of their progeny and also did not determine the teratogenic effects in the fetuses.

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Fernanda Bastos de Mello

Universidade Federal do Rio Grande do Sul

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Marlete Brum Cleff

Universidade Federal de Pelotas

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Augusto Langeloh

Universidade Federal do Rio Grande do Sul

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Renata Osório de Faria

Universidade Federal de Pelotas

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Daniela Jacobus

Universidade Federal do Rio Grande do Sul

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Fernanda Cunha Bastos

Universidade Federal do Rio Grande do Sul

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Isabel Martins Madrid

Universidade Federal de Pelotas

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Stefanie Bressan Waller

Universidade Federal do Rio Grande do Sul

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