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.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 14837 The irradiation parameters investigation of photodynamic therapy on yeast cells2008 - PRATES, RENATO A.; SILVA, ERIQUES G. da; YAMADA JUNIOR, AECIO M.; SUZUKI, LUIS C.; PAULA, CLAUDETE R.; RIBEIRO, MARTHA S.It has been proposed that photodynamic therapy (PDT) can inactivate microbial cells. A range of photosensitizers and light sources were reported as well as different fluence parameters and dye concentrations. However, much more knowledge regarding to the role of fluences, irradiation time and irradiance are required for a better understanding of the photodynamic efficiency. The aims of this study were to investigate the role of light parameters on the photoinactivation of yeast cells, and compare cell survivors in different growing phases following PDT. To perform this study, a suspension (106cfu/mL) of Candida albicans ATCC-90028 was used in log and stationary-phase. Three irradiances 100mW/cm2, 200mW/cm2 and 300mW/cm2 were compared under 3min, 6min and 9min of irradiation, resulting in fluences of 18, 36, 54, 72,108 and 162J/cm2. The light source used was a laser emitting at 660nm with output power of 30, 60 and 90mW. As photosensitizer, 100μΜ methylene blue was used. PDT was efficient against yeast cells (6 log reduction) in log and stationary-phase. Neither photosensitizer nor light alone presented any reduction of cell viability. The increase of irradiance and time of irradiation showed a clearly improvement of cell photoinactivation. Interestingly, the same fluences in different irradiances presented dissimilar effects on cell viability. The irradiance and time of irradiation are important in PDT efficiency. Fluence per se is not the best parameter to compare photoinativation effects on yeast cells. The growing-phases presented the same susceptibility under C. albicans photoinactivation.Artigo IPEN-doc 15656 Real time optical coherence tomography monitoring of Candida albicans biofilm in vitro during photodynamic treatment2010 - SUZUKI, LUIS C.; PRATES, RENATO A.; RAELE, MARCUS P.; FREITAS, ANDERSON Z. de; RIBEIRO, MARTHA S.Artigo IPEN-doc 15795 Parâmetros de irradiação influenciam na inativação de leveduras tratadas com terapia fotodinâmica2010 - PRATES, RENATO A.; SILVA, ERIQUES G. da; SUZUKI, LUIS C.; PAULA, CLAUDETE R.; RIBEIRO, MARTHA S.