Photodynamic antimicrobial therapy of curcumin in biofilms and carious dentine

Photodynamic therapy (PDT) is a technique that involves the activation of photosensitizers by light in the presence of oxygen, resulting in the production of reactive radicals that are capable of inducing cell death. The present study evaluated the susceptibility of Streptococcus mutans and Lactobacillus acidophilus to PDT grown as multi-species in the biofilm phase versus in dentine carious lesions. A brain-heart infusion culture medium supplemented with 1 % glucose, 2 % sucrose, and 1 % young primary culture of L. acidophilus 108 CFU/mL and S. mutans 108 CFU/mL was used to develop multi-species biofilms and to induce caries on human dentine slabs. Five different concentrations of curcumin (0.75, 1.5, 3.0, 4.0, and 5.0 g/L) were used associated with 5.7 J/cm2 light emission diode. Four different groups were analyzed L-D- (control group), L-D+ (drug group), L+D- (light group), and L+D+ (PDT group). ANOVA/Tukey's tests were conducted to compare groups. A significant reduction (p <0.05) in cell viability was observed in the biofilm phase following photosensitization with all curcumin concentrations tested. To achieve significant bacterial reduction (p <0.05) in carious dentine, it was necessary to utilize 5.0 g/L of curcumin in association with blue light. No significant reduction was found for L-D+, supporting the absence of the drug's dark toxicity. S. mutans and L. acidophilus were susceptible to curcumin in the presence of blue light. However, due to light penetration and drug diffusion difficulties, these microorganisms within dentine carious lesions were less affected than they were in the biofilm phase. © 2013 Springer-Verlag London.

Susceptibility of multispecies biofilm to photodynamic therapy using Photodithazine®

This in vitro study evaluated the effect of photodynamic therapy (PDT) on the multispecies biofilm of Candida albicans, Candida glabrata, and Streptococcus mutans. Standardized fungal and bacterial suspensions were cultivated appropriately for each species and inoculated in 96-well microtiter plates for mix-biofilm formation. After 48 h of incubation, the biofilms were submitted to PDT (P + L+) using Photodithazine® (PDZ) at 100, 150, 175, 200, or 250 mg/mL for 20 min and 37.5 J/cm2 of light-emitting diode (LED) (660 nm). Additional samples were treated only with PDZ (P + L-) or LED (P-L+), or neither (control, P-L-). Afterwards, the biofilms were evaluated by quantification of colonies (CFU/mL), metabolic activity (XTT reduction assay), total biomass (crystal violet staining), and confocal scanning laser microscopy (CSLM). Data were analyzed by one-way ANOVA and Tukey tests (p < 0.05). Compared with the control, PDT promoted a significant reduction in colonies viability of the three species evaluated with 175 and 200 mg/mL of PDZ. PDT also significantly reduced the metabolic activity of the biofilms compared with the control, despite the PDZ concentration. However, no significant difference was found in the total biomass of samples submitted or not to PDT. For all analysis, no significant difference was verified among P-L-, P + L-, and P-L+. CSLM showed a visual increase of dead cells after PDT. PDT-mediated PDZ was effective in reducing the cell viability of multispecies biofilm. © 2013 Springer-Verlag London.

Cytotoxicity of Brazilian plant extracts against oral microorganisms of interest to dentistry

Background: With the emergence of strains resistant to conventional antibiotics, it is important to carry studies using alternative methods to control these microorganisms causing important infections, such as the use of products of plant origin that has demonstrated effective antimicrobial activity besides biocompatibility. Therefore, this study aimed to evaluate the antimicrobial activity of plant extracts of Equisetum arvense L., Glycyrrhiza glabra L., Punica granatum L. and Stryphnodendron barbatimam Mart. against Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus mutans, Candida albicans, Candida tropicalis, and Candida glabrata, and to analyze the cytotoxicity of these extracts in cultured murine macrophages (RAW 264.7).Methods: Antimicrobial activity of plant extracts was evaluated by microdilution method based on Clinical and Laboratory Standards Institute (CLSI), M7-A6 and M27-A2 standards. The cytotoxicity of concentrations that eliminated the microorganisms was evaluated by MTT colorimetric method and by quantification of proinflammatory cytokines (IL-1β and TNF-α) using ELISA.Results: In determining the minimum microbicidal concentration, E. arvense L., P. granatum L., and S. barbatimam Mart. extracts at a concentration of 50 mg/mL and G. glabra L. extract at a concentration of 100 mg/mL, were effective against all microorganisms tested. Regarding cell viability, values were 48% for E. arvense L., 76% for P. granatum L, 86% for S. barbatimam Mart. and 79% for G. glabra L. at the same concentrations. About cytokine production after stimulation with the most effective concentrations of the extracts, there was a significant increase of IL-1β in macrophage cultures treated with S. barbatimam Mart. (3.98 pg/mL) and P. granatum L. (7.72 pg/mL) compared to control (2.20 pg/mL) and a significant decrease of TNF-α was observed in cultures treated with G. glabra L. (4.92 pg/mL), S. barbatimam Mart. (0.85 pg/mL), E. arvense L. (0.83 pg/mL), and P. granatum L. (0.00 pg/mL) when compared to control (41.96 pg/mL).Conclusions: All plant extracts were effective against the microorganisms tested. The G. glabra L. extract exhibited least cytotoxicity and the E. arvense L. extract was the most cytotoxic. © 2013 de Oliveira et al.; licensee BioMed Central Ltd.

Comparison of Brazilian plants used to treat gastritis on the oxidative burst of helicobacter pylori -stimulated neutrophil

Ten Brazilian medicinal plants used to treat gastritis and ulcers were carefully selected on the basis of ethnopharmacological importance and antiulcerogenic activity previously described. The antioxidant activity of the methanolic extracts was determined in analysis conditions that simulate a real biological activity on inhibition of the oxidative burst induced in neutrophils using Helicobacter pylori as activator, by a luminol-amplified chemiluminescence assay. The extracts, at low concentration (5 g/mL), exhibited a large variation in inhibitory effects of H. pylori-induced oxidative burst ranging from 48% inhibition to inactive, but all extracts, excluding Byrsonima intermedia, had inhibitory activity over 80% at the concentration of 100 g/mL. The total suppressive antioxidant capacity measured as the effective concentration, which represents the extract concentration producing 50% inhibition of the chemiluminescence induced by H. pylori, varies from 27.2 to 56.8 g/mL and was in the following order: Qualea parviflora > Qualea multiflora > Alchornea triplinervia > Qualea grandiflora > Anacardium humile > Davilla elliptica > Mouriri pusa > Byrsonima basiloba > Alchornea glandulosa > Byrsonima intermedia. The main groups of compounds in tested extracts are presented. Differences in the phytochemical profile, quantitatively and qualitatively, of these plants can explain and justify their protective effect on the gastric mucosa caused by the neutrophil-generated ROS that occurs when H. pylori displays its evasion mechanisms. © 2013 Cibele Bonacorsi et al.

Cytotoxic action of Brazilian propolis in vitro on canine osteosarcoma cells

Osteosarcoma (OSA) is a primary bone neoplasm frequently diagnosed in dogs. The biology of OSA in pet dogs is identical to that of pediatric patients, and it has been considered an excellent model in vivo to study human OSA. Since the individual response to chemotherapy is unpredictable and considering that propolis is a natural product with several biological properties, this work evaluated the cytotoxic action of propolis on canine OSA cells. The primary cell culture of canine OSA was obtained from the tumor of a dog with OSA. Cell viability was assessed after incubation with propolis, 70% ethanol (propolis solvent), and carboplatin after 6, 24, 48, and 72 h. Cell viability was analyzed by the crystal violet method. Data showed that canine OSA cells were sensitive to propolis in a dose- and time-dependent manner and had a distinct morphology compared to control. Its solvent (70% ethanol) had no effect on cell viability, suggesting that the cytotoxic action was exclusively due to propolis. Our propolis sample exerted a cytotoxic effect on canine OSA cells, and its introduction as a possible therapeutic agent in vivo could be investigated, providing a new contribution to OSA treatment. Copyright © 2012 John Wiley & Sons, Ltd.

Neutrophil dysfunction varies with the stage of canine visceral leishmaniosis

Canine visceral leishmaniosis (CVL) causes a dependent-stage alteration in neutrophil oxidative metabolism. When production of reactive oxygen species (ROS) exceeds the antioxidant capacity of neutrophils, apoptosis is triggered, impairing the viability and function of these cells, which can predispose dogs to infection. However, the uremic condition observed in late-stage CVL can also alter the viability and function of human neutrophils. To more clearly understand this relationship, the apoptosis rate and oxidative metabolism of neutrophils from control dogs (n= 20) were compared to dogs in moderate (n= 15) and very severe (n= 15) stage CVL, classified according to LeishVet Consensus. To assess neutrophil oxidative metabolism, superoxide production was measured using the nitroblue tetrazolium reduction test (NBT) in isolated neutrophils. The apoptosis rate of neutrophils was estimated using the morphological method. Moderate-stage dogs presented increased superoxide production, while dogs with very severe stage CVL presented decreased superoxide production and an increase neutrophil apoptosis rate. Leishmaniosis causes differential neutrophil dysfunction according to disease stage. In moderate stage CVL, increased superoxide production is observed with no change in neutrophil viability. However, in very severe stage CVL, decreased superoxide production and increased apoptosis occur associated with uremia. © 2013 Elsevier B.V.

Photodynamic inactivation of clinical isolates of Candida using Photodithazine

This study evaluated the photodynamic inactivation (PDI) mediated by Photodithazine® (PDZ) against 15 clinical isolates of Candida albicans, Candida glabrata and Candida tropicalis. Each isolate, in planktonic and biofilm form, was exposed to PDI by assessing a range of PDZ concentrations and light emitting diode fluences. Cell survival of the planktonic suspensions was determined by colony forming units (CFU ml-1). The antifungal effects of PDI against biofilms were evaluated by CFU ml-1 and metabolic assay. Data were analyzed by non-parametric tests (α = 0.05). Regardless of the species, PDI promoted a significant viability reduction of planktonic yeasts. The highest reduction in cell viability of the biofilms was equivalent to 0.9 log10 (CFU ml-1) for C. albicans, while 1.4 and 1.5 log10 reductions were obtained for C. tropicalis and C. glabrata, respectively. PDI reduced the metabolic activity of biofilms by 62.1, 76.0, and 76.9% for C. albicans, C. tropicalis, and C. glabrata, respectively. PDZ-mediated PDI promoted significant reduction in the viability of Candida isolates. © 2013 Taylor & Francis.

Setting Time Affects In Vitro Biological Properties of Root Canal Sealers

Introduction: Biocompatibility of root canal sealers is important because of the long-term contact of their eluates and/or degradation products with periapical tissues. The literature still lacks studies about the genotoxic effects of these materials and the influence of setting time on biological properties. The cytotoxicity and genotoxicity of an epoxy resin-based sealer (AH Plus), a single methacrylate-based sealer (EndoRez), and a silicone-based sealer (RoekoSeal) were assessed. Methods: Chinese hamster fibroblasts (V79) were cultured and exposed to different dilutions of extracts from the sealers that were left to set for 0, 12, and 24 hours before contact with culture medium. Cell viability was measured by the methyl-thiazol-diphenyltetrazolium assay. Genotoxicity was assessed by the comet assay. Data were statistically analyzed by Kruskal-Wallis and Dunn tests (P < .05). Results: Root canal sealers were statistically more cytotoxic than the untreated control group, except for the silicon-based sealer. Cell viability ranking was the following (from the most to the least cytotoxic): methacrylate-based > epoxy resin-based > silicone-based. The setting time influenced the epoxy resin-based sealer cytotoxicity (decreased at 12 hours) and the general genotoxicity (increased at 24 hours). DNA damage ranking was the following (from the most to the least genotoxic): methacrylate-based > silicone-based = epoxy resin-based. Conclusions: The setting time had influence on the cytotoxicity of the epoxy resin-based sealer and genotoxicity of all tested sealers. The methacrylate-based sealer was the most cytotoxic, and the silicone-based sealer was not cytotoxic. Genotoxicity was observed for all sealers. © 2013 American Association of Endodontists.

Produção de etanol a partir de mosto hidrolisado hemicelulósico de ponta e palha de cana-de-açúcar

Pós-graduação em Microbiologia Agropecuária - FCAV

Caracterização de mutantes condicionais do gene da desoxi-hipusina sintase em Saccharomyces cerevisiae

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

Efeito α-tomatina na proliferação celular, apoptose e expressão de RNAm dos genes APC, Ciclina A2, Catenina, CASP9, BAK, BAX e BCL-XL em células HT29

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Comportamento fermentativo de linhagens industriais de Saccharomyces cerevisiae em mosto com diferentes concentrações de sacarose e fontes estruturalmente complexas de nitrogênio

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracterização bioquímica de leveduras industriais produtoras de etanol cultivadas em diferentes açúcares

Pós-graduação em Biotecnologia - IQ

Liberação das enzimas LDH e PepX e evolução da maturação de queijo parmesão adicionado de culturas autolíticas de Lactobacilus helveticus

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação comparativa da viabilidade celular imediata após osteotomia para implantes com fresas e piezocirurgia em tíbias de coelhos: análise imunoistoquímica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)