LUIS CLAUDIO SUZUKI

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  • Artigo IPEN-doc 23888
    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.
  • Artigo IPEN-doc 23521
    Glucose modulates antimicrobial photodynamic inactivation ofCandida albicans in biofilms
    2017 - 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 18518
    Laser scattering by transcranial rat brain illumination
    2012 - SOUSA, MARCELO V.P.; PRATES, RENATO; KATO, ILKA T.; SABINO, CAETANO P.; SUZUKI, LUIS C.; RIBEIRO, MARTHA S.; YOSHIMURA, ELISABETH M.