Adhesion of Histoplasma capsulatum to pneumocytes and biofilm formation on an abiotic surface

The pathogenic fungus, Histoplasma capsulatum, causes the respiratory and systemic disease 'histoplasmosis'. This disease is primarily acquired via inhalation of aerosolized microconidia or hyphal fragments of H. capsulatum. Evolution of this respiratory disease depends on the ability of H. capsulatum yeasts to survive and replicate within alveolar macrophages. It is known that adhesion to host cells is the first step in colonization and biofilm formation. Some microorganisms become attached to biological and non-biological surfaces due to the formation of biofilms. Based on the importance of biofilms and their persistence on host tissues and cell surfaces, the present study was designed to investigate biofilm formation by H. capsulatum yeasts, as well as their ability to adhere to pneumocyte cells. H. capsulatum biofilm assays were performed in vitro using two different clinical strains of the fungus and biofilms were characterized using scanning electron microscopy. The biofilms were measured using a 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium-hydroxide (XTT) reduction assay. The results showed that both the H. capsulatum strains tested were very efficient at adhering to host cells and forming biofilm. Therefore, this is a possible survival strategy adopted by this fungus.

Surface-expressed enolase contributes to the adhesion of Paracoccidioides brasiliensis to host cells

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Comparative transcriptome analysis of Paracoccidioides brasiliensis during in vitro adhesion to type I collagen and fibronectin: identification of potential adhesins

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Epithelial cells treated with genistein inhibit adhesion and endocytosis of Paracoccidioides brasiliensis

Paracoccidioidomycosis is caused by Paracoccidioides brasiliensis, which although not formally considered an intracellular pathogen, can be internalized by epithelial cells in vitro and in vivo. The mechanisms used by P. brasiliensis to adhere to and invade non-professional phagocytes have not been identified. The signal-transduction networks, involving protein tyrosine kinase (PTK) and protein phosphatase activities, can modulate crucial events during fungal infections. In this study, the involvement of PTK has been investigated in P. brasiliensis adherence and invasion in mammalian epithelial cells. A significant inhibition of the fungal invasion occurred after the pre-treatment of the epithelial cells with genistein, a specific tyrosine kinase inhibitor, indicating that the tyrosine kinase pathway is involved in P. brasiliensis internalization. In contrast, when the fungus was treated, a slight (not significant) inhibition of PTK was observed, suggesting that PTK might not be the fungus' transduction signal pathway during the invasion process of epithelial cells. An intense PTK immunofluorescence labeling was observed in the periphery of the P. brasiliensis infected cells, little PTK labeling was found in both uninfected cells and yeast cells, at later infection times (8 and 24 h). Moreover, when the epithelial cells were treated with genistein and infected with P. brasiliensis, no labeling was observed, suggesting the importance of the PTK in the infectious process. These results suggest that PTK pathway participates in the transduction signal during the initial events of the adhesion and invasion processes of P. brasiliensis to mammalian epithelial cells.

Morphological Features of the Apical Region in the Principal Cells of Mongrel Dog Epididymis

The epithelial principal cells are the predominant cell type of the epididymis. These cells have been shown to be both secretory and endocytic cells. The apical region of the cytoplasm of principal cells in the mongrel dog are located close to the cell apex and tubular lumen, and shown microvilli at the luminal border and present a endocytic apparatus, that consists of coated pits and vesicles, endosomes of varying size, multivesicular bodies, and lysosomes. The endosomes, multivesicular bodies and lysosomes contained the electron-dense patches. These results suggest that principal cells of the epididymis in the dog as possess a highly developed endocytic apparatus play a role in endocytosis. These cells function are similarly to the related in other mammals, in performing endocytosis.

Markers of uremia and pericardial effusion in peritoneal dialysis

Inadequate dialysis causes accumulation of toxic residues that may lead to the development of dialysis-associated pericardial effusion, but several other factors could be associated with this abnormality. The purpose of this study was to evaluate clinical risk factors to asymptomatic pericardial effusion in peritoneal dialysis.This cross-sectional study included 34 patients aged a parts per thousand yen18 years on peritoneal dialysis for at least 3 months, who showed no symptomatic pericardial effusion, hepatic cirrhosis, neoplasias, lupus or amputations, none in minoxidil use. Asymptomatic pericardial effusion was diagnosed by echocardiography. Risk factors were evaluated by logistic regression and Roc curve. Significance level was set at P < 0.05.Patient age was 51 +/- A 15.9 years. of the 34 patients enrolled, 16 were men and 11 diabetic. Five of them presented pericardial effusion. Logistic regression identifies low hemoglobin level (RR 0.454 CI 95%: 0.225-0.913; P = 0.027), low phase angle (RR 0.236 CI 95%: 0.057-0.984; P = 0.048) and low Kt/V (RR 0.001 CI 95%: 0.0-0.492; P = 0.03) as risk factors to pericardial effusion. Roc curve showed that hemoglobin levels below 12.2 g/dL, Kt/V lower than 1.9 and phase angle lower than 4.5A degrees were the best cutoffs to predict pericardial effusion. Four patients showed these three parameters in the unfavorable range, and all these four patients presented pericardial effusion. The other patient with pericardial effusion had two of these parameters reduced.These findings corroborate the hypothesis that uremia plays a significant role in the pathogenesis of dialysis-associated pericardial effusion.

Evaluation of in vitro and in vivo adhesion and immunomodulatory effect of Lactobacillus species strains isolated from chickens

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Poda apical, densidade de plantas e cobertura plástica do solo na produtividade do tomateiro em cultivo protegido

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Lack of influence of the Schneiderian membrane in forming new bone apical to implants simultaneously installed with sinus floor elevation: an experimental study in monkeys

Aim: To describe the early healing processes around the implants installed after elevation of the sinus mucosa applying the lateral access technique without the use of grafting material.Material and methods: Immediately after the elevation of the maxillary sinus Schneiderian membrane by the lateral approach in eight monkeys, implants were installed without the use of grafting material. The healing of the tissue around the implants was evaluated after 4, 10, 20 and 30 days. Ground sections were prepared and analyzed histologically.Results: After 4 days of healing, the formation of coagulum and provisional matrix was documented within the elevated area. At 10-day interval, sprouts of woven bone were in continuity with the parent bone, and partly in contact with the implant surface at the base of the augmented area. While bone-to-implant contact increased after 20 and 30 days, the area underneath the Schneiderian membrane appeared reduced in volume and condensed toward the apex of the implants. The sinus mucosa was to some extent collapsed onto the implant surface and on the newly formed bone.Conclusions: The void initially occupied by the coagulum after sinus membrane elevation shrank substantially during the observation period. A lack of influence of the Schneiderian membrane in bone formation apical to implants was documented in the early phase of healing.

The growing importance of materials that prevent microbial adhesion: antimicrobial effect of medical devices containing silver

Research has clarified the properties required for polymers that resist bacterial colonisation for use in medical devices. The increase in antibiotic-resistant microorganisms has prompted interest in the use of silver as an antimicrobial agent. Silver-based polymers can protect the inner and outer surfaces of devices against the attachment of microorganisms. Thus, this review focuses on the mechanisms of various silver forms as antimicrobial agents against different microorganisms and biofilms as well as the dissociation of silver ions and the resulting reduction in antimicrobial efficacy for medical devices. This work suggests that the characteristics of released silver ions depend on the nature of the silver antimicrobial used and the polymer matrix. In addition, the elementary silver, silver zeolite and silver nanoparticles, used in polymers or as coatings could be used as antimicrobial biomaterials for a variety of promising applications. (C) 2009 Elsevier B. V. and the International Society of Chemotherapy. All rights reserved.

Análise radiográfica computadorizada da reabsorção radicular apical após a utilização de duas mecânicas ortodônticas

OBJETIVO: a reabsorção radicular apical é uma condição comumente observada durante e após o tratamento ortodôntico e fatores como tipo de aparelhagem ortodôntica utilizada, magnitude das forças aplicadas e duração do tratamento podem estar relacionados ao processo de arredondamento do ápice radicular. Buscou-se avaliar, por meio de imagens radiográficas computadorizadas, a quantidade de reabsorção no ápice radicular, quando da utilização de duas diferentes técnicas de mecânica ortodôntica fixa: Edgewise com acessórios padrão e Edgewise com acessórios totalmente programados. METODOLOGIA: a amostra constituiu-se de 20 pacientes tratados pelo mesmo profissional na Clínica de Ortodontia da Faculdade de Odontologia de Araçatuba - UNESP. Os pacientes foram divididos em dois grupos: grupo 1 (Tratados com Edgewise com acessórios padrão e fios de aço) e grupo 2 (Tratados com Edgewise com acessórios totalmente programados e fios de níquel-titânio). A avaliação radiográfica digital foi realizada por um único operador por meio de exposições radiográficas digitais feitas no início do tratamento ortodôntico, após retração de caninos e final de tratamento, utilizando o sistema de escores proposto por Levander e Malmgren (1988). RESULTADOS E CONCLUSÕES: a análise dos escores permitiu concluir que o tratamento ortodôntico empregando a técnica Edgewise com acessórios totalmente programados e fios de níquel-titânio apresentou menores graus de reabsorção radicular apical, em comparação à técnica Edgewise com acessórios padrão e fios de aço. Observou-se que, independentemente da técnica empregada, o tratamento ortodôntico como um todo apresentou um grau moderado de reabsorção radicular apical.

Influence of the type of vehicle and limit of obturation on apical and periapical tissue response in dogs' teeth after root canal filling with mineral trioxide aggregate

The purpose of this study was to investigate the influence of the type of vehicle (distilled water or propyleneglycol) on the response of apical tissues of dogs' teeth after root canal filling with mineral trioxide aggregate (MTA) at two different limits. Forty roots of incisors and premolars of two adult dogs were used. After pulpectomy, the root canals were prepared biomechanically, and the roots had the apical cemental barrier penetrated with a #15 K-file and widened to a #25 K-file. The root canals were assigned to four groups according to the vehicle used for MTA (ProRoot-MTA; Tulsa Dental, Tulsa, OK) preparation and the limit of root canal filling: group 1, filling with MTA/distilled water to the limit of the cemental canal; group 2, overfilling with MTA/distilled water, group 3, filling with MTA/propyleneglycol to the limit of the cemental canal; and group 4, overfilling with MTAlpropyleneglycol. The animals were killed by anesthetic overdose 90 days after endodontic treatment and the anatomic pieces were prepared for histomorphological analysis. The sections were stained with hematoxylin and eosin and Brown and Brenn techniques. The results showed that MTA pastes prepared with either distilled water or propyleneglycol as vehicles had similar biological behavior (p > 0.05); root fillings placed at the cemental canal limit showed better results than the overfillings (p = 0.01), and MTA/propyleneglycol paste was more easily placed into the root canals than MTA/distilled water paste.

Influence of apical patency and filling material on healing process of dogs' teeth with vital pulp after root canal therapy

Foi propósito deste trabalho observar o processo de reparo de dentes de cães após obturação dos canais com dois cimentos diferentes, fazendo ou não a patência apical. Após uma sobreinstrumentação, os canais receberam um curativo de uma solução de corticosteróide-antibiótico por 7 dias, com o objetivo de obter invaginação de tecido conjuntivo para dentro dos canais. Após esse período, esse tecido foi totalmente removido em metade dos casos (grupos com patência apical) e preservados no restante dos casos (grupos sem patência apical). Os canais foram obturados pela técnica da condensação lateral empregando um cimento a base de hidróxido de cálcio (Sealer Plus) ou um cimento de Grossman (Fill Canal). Os animais foram sacrificados por overdose anestésica 60 dias após o tratamento endodôntico e as peças anatômicas foram obtidas e preparadas para análise histológica. Os dados obtidos foram analisados com base em diversos parâmetros histomorfológicos. Os resultados foram melhores nos grupos sem patência apical (p=0,01) do que nos grupos com patência. Dentre os cimentos estudados, os melhores resultados foram observados com o cimento Sealer Plus (p=0,01). em conclusão, tanto a patência apical (presença ou ausência) quanto o tipo de material obturador de canal influíram no processo de reparo apical de dentes de cães com polpas vitais após tratamento endodôntico. O emprego de um cimento a base de hidróxido de cálcio em dentes sem patência apical promoveu os melhores resultados, dentre as condições experimentais propostas.

Antimicrobial potential of medicaments used in healing process in dogs' teeth with apical periodontitis

Estudou-se a influência de diferentes irrigantes no potencial antimicrobiano da pasta de hidróxido de cálcio em dentes de cães com periodontite apical. 48 pré-molares de cães adultos tiveram suas câmaras coronárias abertas e expostas à cavidade bucal por 6 meses. Os canais radiculares foram preparados, irrigados e medicados com diferentes substâncias, de acordo com os seguintes grupos: 1) 2,5% NaOCl + CHP; 2) 2% CHX + CHP; 3) vinagre + CHP; 4) vinagre + vinagre. No grupo 4, a solução irrigante e a medicação intracanal utilizada foi o vinagre. Neste grupo, a cada 7 dias, a solução era renovada. Cada amostra foi coletada, mantendo-se o cone de papel esterilizado em posição por 1 min, e a seguir transportado e imerso em 7 mL de Letheen broth, seguido de incubação a 37ºC por 48 h. O crescimento microbiano foi analisado por dois métodos, turbidade do meio de cultura e subcultura em meio nutritivo específico (brain heart infusion). Os resultados mostraram que em todos os grupos experimentais houve crescimento microbiano após 21 dias, em diferentes percentagens: grupo 1 - 30%; grupo 2 - 30%; grupo 3 - 40%; grupo 4 - 60%. Todos os materiais testados apresentaram potencial antimicrobiano. Entretanto, o processo de cura favorecido pela pasta de hidróxido de cálcio não pode ser esquecido, uma vez que muitos estudos já demonstraram sua ação antimicrobiana.