LUIS CLAUDIO SUZUKI
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Artigo IPEN-doc 25857 Effect of photodynamic antimicrobial chemotherapy on Candida albicans in the presence of glucose2019 - OLIVEIRA-SILVA, TAMIRES de; ALVARENGA, LETICIA H.; LIMA-LEAL, CINTIA; GODOY-MIRANDA, BIANCA; CARRIBEIRO, PAMELA; SUZUKI, LUIS C.; RIBEIRO, MARTHA S.; KATO, ILKA T.; PAVANI, CHRISTIANE; PRATES, RENATO A.Background: Candida albicans is an opportunistic commensal microorganism, often associated with severe infections in immunosuppressed individuals. C. albicans has hexose transporters that may favor the intracellular accumulation of photosensitizer (PS). the aims of this study were to investigate the influence of glucose load on photodynamic antimicrobial chemotherapy (PACT); and the role that membrane transport system plays on this therapy in the presence of glucose. Material and methods: Strains of C. albicans were selected: ATCC 10231, YEM 12, YEM 13, YEM 14 and YEM 15. All strains were grown aerobically on Sabouraud agar and incubated at 30 °C for 24 h. The strains were treated with and without glucose, and divided into Control (no treatment), LED light (660 nm, 166 mW/cm2), Photosensitizer (100 μM methylene blue) and PACT at 1, 3 and 6 min of irradiation groups. The colony forming units were counted and data submitted to statistical analysis (ANOVA) and Tukey's test. The concentration of methylene blue (MB) outside the yeast was measured by fluorescence spectroscopy. Results: PACT inactivate C. albicans and the presence of glucose did not affect the killing effect for most strains. Only YEM12 was partially affected by its presence. Regarding efflux systems, ABC overexpressing strain showed a protective effect on the yeast cells. We observed that yeast with overexpression of major facilitator superfamily (MFS) membrane pore tended to accumulate more MB in its cytoplasm, whereas strains that overexpressed ABC pumps (ATP-binding cassette transporters) tended to decrease MB uptake and survive the photodynamic challenge. Conclusion: Presence of glucose showed a small effect on PACT . The accumulation of MB on yeast induces more photodynamic inactivation; however, the photodynamic efficacy depends on the type and characteristics of the microbial strain.Resumo IPEN-doc 24879 Sensitization of glucose sensors as a pathway for increased uptake of methylene blue in Candida albicans with multidrug efflux systems2017 - OLIVEIRA-SILVA, T.; LIMA-LEAL, C.R.; ALVARENGA, L.H.; SUZUKI, L.C.; KATO, I.T.; RIBEIRO, M.S.; PRATES, R.A.Artigo IPEN-doc 23075 The In Situ effect of titanium tetrafluoride gel on erosion/abrasion progression in human dentin2017 - MANTILLA, TAIS F.; TURSSI, CECILIA P.; RAMOS-OLIVEIRA, THAYANNE M.; SILVA, CAMILA V. da; SUZUKI, LUIS C.; FREITAS, PATRICIA M. deErosion incidence is increasing and its control is still a challenge in clinical practice. This study evaluated 4% TiF4-gel effects on eroded human dentin subjected to in situ erosive/ abrasive episodes. Seventy-two previously eroded dentin slabs (0.05 M citric acid, pH 2.3, 20 min) were allocated to 6 groups (n=12) according to the treatment to be performed during the in situ phase and number of erosive/abrasive cycles, as follows: 4% TiF4-gel applied once (TiF41), twice (TiF42) or three times (TiF43) followed by 1, 2 and 3 erosive/ abrasive cycles, respectively. Gel was applied before the beginning of the next cycle. Control groups were subjected to 1 (C1), 2 (C2) and 3 (C3) erosive/abrasive cycles only. A seventh group (n=12) comprised in vitro uneroded samples (UN) subjected to 3 erosive/ abrasive cycles. Each cycle corresponded to 2 days of erosive (citric acid 0.5%, pH 2.6, 6x/day) and abrasive (electric toothbrush, 10 s/sample, 1 x/day) challenges. Samples were evaluated under profilometry and environmental scanning electron microscopy (ESEM). Atomic force microscopy images (AFM) were also made (n=3). Repeated measures 2-way ANOVA and Tukey test (p<0.001) showed that TiF42, which did not differ from TiF41 and TiF43, revealed a significant reduction in surface loss compared to all control groups. TiF41 and TiF43 showed no significant difference from C1, but both groups demonstrated significantly smaller surface loss than C2 and C3. ESEM and AFM micrographs suggested alterations on treated surfaces compared to samples from control groups, showing reduced diameters of dentinal tubules lumens. Therefore, TiF4 was able to reduce the progression of erosive/abrasive lesions.Artigo IPEN-doc 23888 Inhomogeneity in optical properties of rat brain: a study for LLLT dosimetry2013 - 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.Artigo IPEN-doc 23521 Glucose modulates antimicrobial photodynamic inactivation ofCandida albicans in biofilms2017 - SUZUKI, LUIS C.; KATO, ILKA T.; PRATES, RENATO A.; SABINO, CAETANO P.; YOSHIMURA, TANIA M.; SILVA, TAMIRES O.; RIBEIRO, MARTHA S.Candida albicans biofilm is a main cause of infections associated with medical devices such as catheters,contact lens and artificial joint prosthesis. The current treatment comprises antifungal chemotherapy thatpresents low success rates. Photodynamic inactivation (PDI) involves the combination of a photosensitiz-ing compound (PS) and light to generate oxidative stress that has demonstrated effective antimicrobialactivity against a broad-spectrum of pathogens, including C. albicans. This fungus senses glucose induc-ing an upregulation of membrane transporters that can facilitate PS uptake into the cell. The aim ofthis study was to evaluate the effects of glucose on methylene blue (MB) uptake and its influence onPDI efficiency when combined to a red LED with central wavelength at = 660 nm. C. albicans biofilmswere grown on hydrogel disks. Prior to PDI assays, MB uptake tests were performed with and withoutglucose-sensitization. In this system, the optimum PS administration was determined as 500 M of MBin contact with the biofilm during 30 min before irradiation. Irradiation was performed during 3, 6, 9, 12,15 and 18 min with irradiance of 127.3 mW/cm2. Our results showed that glucose was able to increaseMB uptake in C. albicans cells. In addition, PDI without glucose showed a higher viability reduction until6 min; after 9 min, glucose group demonstrated a significant decrease in cell viability when compared toglucose-free group. Taken together, our data suggest that glucose is capable to enhance MB uptake andmodulate photodynamic inactivation of C. albicans biofilm.Artigo IPEN-doc 20714 Aggregatibacter actinomycetemcomitans biofilm can be inactivated by methylene blue-mediated photodynamic therapy2015 - 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, EDUARDOResumo IPEN-doc 17759 Photosensitization of Actinobacillus actinomycetemcomitans with malachite green and methylene blue: microbiological analysis2006 - YAMADA JUNIOR, A.M.; PRATES, R.A.; HASHIMOTO, M.C.; SUZUKI, L.C.; CAI, S.; RIBEIRO, M.S.Resumo IPEN-doc 17758 Histological analysis in ligature induced periodontitis in rats following photodynamic therapy2006 - YAMADA JUNIOR, A.M.; PRATES, R.A.; SUZUKI, L.C.; VILLA, N.; CAI, S.; RIBEIRO, M.S.Artigo IPEN-doc 18518 Laser scattering by transcranial rat brain illumination2012 - SOUSA, MARCELO V.P.; PRATES, RENATO; KATO, ILKA T.; SABINO, CAETANO P.; SUZUKI, LUIS C.; RIBEIRO, MARTHA S.; YOSHIMURA, ELISABETH M.Artigo IPEN-doc 11897 Bactericidal effect of malachite green and red laser on Antinobacillus actinomycetemcomitans2007 - PRATES, RENATO A.; YAMADA JUNIOR, AECIO M.; SUZUKI, LUIS C.; HASHIMOTO, MARIA C.E.; CAI, SILVANA; SOARES, SHEILA G.; GOMES, LAERCIO; RIBEIRO, MARTHA S.