RENATO ARAÚJO PRATES

RENATO ARAÚJO PRATES

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Incorporation of the methylene blue photosensitizer in the presence of glucose in strains of candida albicans with multidrug efflux systems
2017 - SILVA, TAMIRES; ALVARENGA, LETICIA; LEAL, CINTIA; MIRANDA, BIANCA G.; SUZUKI, LUIZ C.; KATO, ILKA; RIBEIRO, MARTHA; PAVANI, CHRISTIANE; PRATES, RENATO
Background: Infectious diseases are responsible for 60% of deaths in developing countries.Candida albicans cause severe infection in immunocompromised patients and the commonly used treatments have not been effective against microbial resistance. Photodynamic therapy (PDT) is a new promising strategy to microbial inactivation based on the use of photosensitizer (PS) in the presence of oxygen and activation by light to form reactive oxygen species.C.albicanshas glucose sensors which could facilitate the entrance of the PS. The objective of this study was to evaluate the role of glucose in the photodynamic inactivation of C. albicans. Study: C. albicans ATCC 10231, YEM 12, YEM 13, YEM 14, and YEM15were aerobically grown on Sabouraud agar and incubated at 308C for 24 hours. Microbial inoculants were divided into 4 groups with and without glucose: Control; Only irradiation; PS toxicity and PDT groups with three irradiation times.After going throughthe treatments, the colony-forming units were counted and the data were subjected to statistical analysis (ANOVA) and Tukey test. To measure the concentration ofMB, fluorescence spectroscopy and flow cytometry were used. Results: We observed that yeast with overexpression of Major Facilitator Superfamily membrane pore tend to accumulate more MB in its cytoplasm, whereas strains that overexpress ABC pumps demonstrated the greater survival against the photodynamic challenge. Conclusion: PDT is an efficient strategy against C. albicans and the presence of glucose can intervene in the photodynamic effect. The presence of MB in the intracellular region of the yeast predisposes to greater photodynamic inactivation, however, its germicidal capacity is related to the type and characteristics of the microbial.
Application of photodynamic therapy with led and methylene blue in streptococcus mutans in the presence of glucose- in vitro study
2017 - LEAL, CINTIA; ALVARENGA, LETICIA; SILVA, TAMIRES; BUSSADORI, SANDRA; KATO, ILKA; RIBEIRO, MARTHA; PRATES, RENATO
Background: Streptococcus mutans is a microorganism associated with tooth decay; many genes that express adhesion, biofilm formation, extracellular polysaccharide, carbohydrate uptake and acid tolerance regulate its cariogenic properties. S. mutans inhabits a complex biofilm and it produces a large amount of exopolysaccharides to promote adhesion and enabling transport pumps. Photodynamic therapy involves the use of a photosensitizer (PS), which is absorbed by specific cells followed by irradiation with visible light, resulting in cell death. The aim of this study was to investigate antimicrobial photodynamic therapy on Streptococcus mutans in the presence of glucose. Study: Streptococcus mutans was grown in brain heart infusion (BHI) at 37 8C for 48 h. Inocula were prepared with pure colonies, which were suspended in phosphate buffered saline (PBS) with and without 50mM glucose. One-hundred micromolar methylene blue was used as photosensitizer and the experiments were performed with groups (control, irradiated with LED, FS without irradiation, and PDT 30, 60, and 120 s). Colony form units were counted and statistically analyzed (oneway ANOVA and Tukey 5%). Results: The irradiation as well as the photosensitizer in the dark did not cause cell death. In contrast, in experiments without glucose, PDT caused cell death proportional the amount of light used. The more light, the higher the inactivation of S. mutans and after 2 min a reduction of 7 orders of magnitude (100%) was observed. In experiments with glucose cell death was observed even increasing the radiant exposure. Conclusion: We concluded that PDT is a viable solution for inactivation of S. mutans in suspension, and that the presence of glucose activates efflux pumps in the bacterial cell wall, and it drastically reduces the effect of PDT.
Inhomogeneity in optical properties of rat brain: a study for LLLT dosimetry
2013 - SOUSA, MARCELO V.P.; PRATES, RENATO; KATO, ILKA T.; SABINO, CAETANO P.; YOSHIMURA, TANIA M.; SUZUKI, LUIS C.; MAGALHAES, ANA C.; YOSHIMURA, ELISABETH M.; RIBEIRO, MARTHA S.
Over the last few years, low-level light therapy (LLLT) has shown an incredible suitability for a wide range of applications for central nervous system (CNS) related diseases. In this therapeutic modality light dosimetry is extremely critical so the study of light propagation through the CNS organs is of great importance. To better understand how light intensity is delivered to the most relevant neural sites we evaluated optical transmission through slices of rat brain point by point. We experimented red (λ = 660 nm) and near infrared (λ = 808 nm) diode laser light analyzing the light penetration and distribution in the whole brain. A fresh Wistar rat (Rattus novergicus) brain was cut in sagittal slices and illuminated with a broad light beam. A high-resolution digital camera was employed to acquire data of transmitted light. Spatial profiles of the light transmitted through the sample were obtained from the images. Peaks and valleys in the profiles show sites where light was less or more attenuated. The peak intensities provide information about total attenuation and the peak widths are correlated to the scattering coefficient at that individual portion of the sample. The outcomes of this study provide remarkable information for LLLT dose-dependent studies involving CNS and highlight the importance of LLLT dosimetry in CNS organs for large range of applications in animal and human diseases.
Red laser attenuation in biological tissues: study of the inflammatory process and pigmentation influence
2012 - SABINO, CAETANO P.; MENEGUZZO, DAIANE T.; BENETTI, ENDI; KATO, ILKA T.; PRATES, RENATO A.; RIBEIRO, MARTHA S.
In vitro effect photodynamic therapy with LED and methylene blue on Candida albicans pretreated with glucose
2016 - SILVA, TAMIRES O.; SUZUKI, LUIS; KATO, ILKA; DEANA, ALESSANDRO; RIBEIRO, MARTHA; PRATES, RENATO
Ultrastructural changes following antimicrobial photodynamic therapy on Candida albicans
2016 - PRATES, RENATO; SANTOS, CAMILA; ARANHA CHAVES, VICTOR; RIBEIRO, MARTHA; KATO, ILKA
Estudo comparativo entre dois comprimentos de onda no efeito fotodinâmico em biofilmes de Candida albicans
2014 - SUZUKI, L.C.; YOSHIMURA, T.M.; KATO, I.T.; PRATES, R.A.; RIBEIRO, M.S.
Aggregatibacter actinomycetemcomitans biofilm can be inactivated by methylene blue-mediated photodynamic therapy
2015 - ALVARENGA, LETICIA H.; PRATES, RENATO A.; YOSHIMURA, TANIA M.; KATO, ILKA T.; SUZUKI, LUIS C.; RIBEIRO, MARTHA S.; FERREIRA, LUIS R.; PEREIRA, SILVIO A. dos S.; MARTINEZ, ELIZABETH F.; SABA CHUJFI, EDUARDO
Photodynamic therapy has antifungal effect and reduces inflammatory signals in Candida albicans-induced murine vaginitis
2014 - SENA, R.M.M. de; CORREA, L.; KATO, I.T.; PRATES, R.A.; SENNA, A.M.; SANTOS, C.C.; PICANCO, D.A.; RIBEIRO, M.S.
Terapia fotodinamica: mecaniscos e aplicacoes
2010 - PRATES, RENATO A.; YAMADA JUNIOR, AECIO M.; HASHIMOTO, MARIA C.; RIBEIRO, MARTHA S.