RENATO ARAÚJO PRATES

RENATO ARAÚJO PRATES

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Periodontal treatment combined to antimicrobial photodynamic therapy
2017 - GODOY-MIRANDA, BIANCA; BELINELLO-SOUZA, ESTEFANI; ALVARENGA, LETICIA; LEAL, CINTIA; LEITE, CAROLINA; LIMA, TAIRINE; PREVIATI-OLIVEIRA, JHOSEPHER; FREITAS, ANDERSON; PRETTO, LUCAS de; FERNANDES, ADJACI; PRATES, RENATO
Background: Antimicrobial photodynamic therapy (APDT) has been used as an adjuvant treatment for periodontitis. It combines a photosensitizer (PS) with a light source to induce reactive oxygen species (ROS) and kill microbial cells. PpNetNI is a protoporphyrin derivate, and it has a chemical binding site at biofilm and great affinity to microbial cells. The aim of this study was to investigate the effects of APDT as an adjuvant treatment for periodontitis. Study: Ten healthy male rats Wistar (Rattus norvegicus) were used in this study (Approved by UNINOVE Ethical committee AN0029/2015). Periodontitis was induced by placing a cotton ligature around the first mandibular molar in a subgingival position. The contralateral mandibular first molar received neither a ligature nor any treatment, and was used as a control. After 7 days, the ligature was removed and all animals received scaling and root planning (SRP) and were divided according to the following treatments: SRP group (received SRP and irrigation with PpNetNI, 10 mM) and PDT group (PpNetNI 10 mM followed by LED irradiation). PDT was performed with a LED (630 nm) with an output power of 400mW (fluence-rate 200mW/cm2; fluence 18 J/cm2). Rats were euthanized at 7 days postoperatively. The bone loss was measured by Optical Coherence Tomography (OCT, THORLABS LTD., Newton, US). Data were analyzed statistically (Mann-Whitney test, p<0.05). in vestibular region of the first molar Results: The animals treated by APDT showed a bone gain of approximately 30% compared to the SRP group following 7 days from the treatment. OCT was able to detect bone loss in the samples and it was nondestructive method for this experimental model. Conclusion: In conclusion, within the parameters used in this study, APDT was an effective alternative to held periodontal health after treatment, and it was able to regenerate supportive periodontal tissue.
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.
Low Intensity laser therapy in patients with burning mouth syndrome: a randomized, placebo-controlled study
2016 - SUGAYA, NORBERTO N.; SILVA, ERICA F.P. da; KATO, ILKA T.; PRATES, RENATO; GALLO, CAMILA de B.; PELLEGRINI, VIVIAN D.
The aim of this study was to assess the effectiveness of low intensity laser therapy in patients with Burning Mouth Syndrome (BMS). Thirty BMS subjects were randomized into two groups -Laser (LG) and Placebo (CG). Seven patients dropped out, leaving 13 patients in LG and 10 patients in CG. Each patient received 4 irradiations (laser or placebo) twice a week, for two consecutive weeks (blinded to the type of irradiation received). Infrared laser (AsGaAI) irradiations were applied to the affected mucosa in scanning mode, wavelength of 790 nm, output power of 20 mW and fluence of 6 J/cm(2). A visual analogue scale (VAS) was used to assess the therapeutic effect before and after each irradiation, and at all the control time periods: 7, 14, 30, 60 and 90 days after the last irradiation. One researcher delivered irradiation and another recorded the results. Both researchers were blinded, the first to the results, and the second to the type of radiation applied. The results were categorized according to the percentage of symptom level variation, and showed a statistically better response in LG in only two categories of the control checkpoints (p=0.02; Fisher's Exact Test). According to the protocol used in this study, low intensity laser therapy is as beneficial to patients with BMS as placebo treatment, indicating a great emotional component of involvement in BMS symptomatology. Nevertheless, there were positive results in some statistical analyses, thus encouraging further research in BMS laser therapy with other irradiation parameters.
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
Desenvolvimento de metodologia para o estudo do efeito fotodinâmico em infecções fúngicas
2012 - SILVA, LARISSA S. da; PRATES, RENATO A.
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.