VIVIANE PEREIRA GOULART

VIVIANE PEREIRA GOULART

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FTIR for the study of the biochemical changes promoted by PDT mediated by 5-ALA and its methyl-ester in neoplastic skin lesions
2016 - ZEZELL, D.M.; LIMA, C.A.; GOULART, V.P.
Laser-induced fluorescence spectroscopy assess the Protoporphyrin IX generated by 5-aminolevulinic acid and its methyl ester in cutaneous malignant lesions
2016 - LIMA, CASSIO A.; GOULART, VIVIANE P.; ZEZELL, DENISE M.
Photodynamic therapy (PDT) of tumors is a therapeutic modality considered for the treatment of nonmelanoma skin cancers (NMSC) and other cutaneous diseases. PDT is a minimally invasive method, avoiding surgical intervention or the use of ionizing radiation. The cell death induced by PDT results from the local oxidative stress promoted by reactive oxygen species (ROS) induced by a photosensitizing drug activated by light of specific wavelength. The 5-aminolevulinic acid (ALA) and its methylated ester (MAL) as precursors of the endogenous photosensitizer protoporphyrin IX (PpIX) have been widely studied for the topical treatment of NMSC and other cutaneous diseases. However, the detailed role of PpIX generated by ALA/MAL in diseased and normal skin is incomplete. Understanding the PpIX fluorescence in neoplastic skin may be useful for optimization of PDT while minimizing side effects in the surrounding normal tissue. In this way, this study aimed to use laser-induced fluorescence (LIF) spectroscopy to evaluate the generation of PpIX in squamous cell carcinoma using photosensitizer creams based on ALA and MAL. Neoplastic lesions were induced in 20 Swiss mice using a well-established multi-stage chemical-carcinogenesis protocol and the PpIX generated in the mouse skin was monitored non-invasively by the fluorescence signal emitted after application of each photosensitizer. LIF measurements were collected every 30 minutes on the shaved backs of the mice using a bifurcated fiber-optic probe connected to a spectrometer. A diode laser emitting at 405 nm was used as excitation wavelength and fluorescence emission was measured at 635 nm. Measurements were recorded using the SpectraSuite software (Ocean Optics, USA) and the spectra were normalized by the power emitted by the diode laser as well as by the fluorescence intensity at 405nm. A pairwise comparison using T-Student statistical test was performed in each time interval and the data were considered statistically different for p-values  0.05. Our results showed no statistical significant difference between the groups for 0–90 minutes. On the other hand, the fluorescence intensity for neoplastic skin submitted to ALA was higher than that from tissue submitted to MAL at all times after 90 minutes and showed an increasing behavior with slight fluctuations over time. Considering the lipophilic and charge characteristics from MAL, we concluded that the lowest LIF measurements collected from tissue underwent this prodrug resulted from its higher penetration into the skin, whereas the highest PpIX emission obtained for ALA is an indicative of superficial generation of PpIX and its poor penetration into the tissue.
Chemometric methods applied to FTIR spectra to discriminate treated and non-treated cutaneous malignant lesions from healthy skin
2016 - LIMA, CASSIO A.; GOULART, VIVIANE; ZEZELL, DENISE
Chemometric methods were used to differentiate FTIR spectra of treated and nontreated malignant lesions from healthy skin. We conclude that the method can be used to evaluate the biological changes promoted by photodynamic treatment.
Evaluation of squamous cell skin carcinoma using ATR-FTIR spectroscopy associated to cluster analysis
2014 - LIMA, C.A.; GOULART, V.; ZEZELL, D.M.
Cluster Analysis were used as an unsupervised classification technique to differentiate FTIR spectra of normal and tumor skin. The results shown satisfactory separation in samples analyzed, highlighting the potential of the technique for diagnostic purposes.
Efeito do laser de Nd:YAG na resistência a desmineralização do esmalte quando associado a aplicação de fluoreto
2008 - GOULART, VIVIANE P.; ZEZELL, DENISE M.
Aplicação de técnicas quimiométricas associadas a espectroscopia FT-IR para discriminar tecido sadio de lesões cutâneas potenciamente malignas
2015 - LIMA, CASSIO A.; GOULART, VIVIANE P.; ZEZELL, DENISE M.
Biochemical changes in cutaneous squamous cell carcinoma submitted to PDT using ATR-FTIR spectroscopy
2015 - LIMA, CASSIO A.; GOULART, VIVIANE P.; CASTRO, PEDRO A.A. de; CORREA, LUCIANA; BENETTI, CAROLINA; ZEZELL, DENISE M.
Nonmelanoma skin cancers are the most common form of malignancy in humans. Between the traditional treatment ways, the photodynamic therapy (PDT) is a promising alternative which is minimally invasive and do not requires surgical intervention or exposure to ionizing radiation. The understanding of the cascade of effects playing role in PDT is not fully understood, so that define and understand the biochemical events caused by photodynamic effect will hopefully result in designing better PDT protocols. In this study we investigated the potential of the FTIR spectroscopy to assess the biochemical changes caused by photodynamic therapy after 10 and 20 days of treatment using 5-aminolevulinic acid (ALA) as precursor of the photosensitizer photoporphyrin IX (PpIX). The amplitude values of second derivative from vibrational modes obtained with FTIR spectroscopy showed similar behavior with the morphological features observed in histopathological analysis, which showed active lesions even 20 days after PDT. Thus, the technique has the potential to be used to complement the investigation of the main biochemical changes that photodynamic therapy promotes in tissue.
ATR-FTIR spectroscopy for the assessment of biochemical changes in skin due to cutaneous squamous cell carcinoma
2015 - LIMA, CASSIO A.; GOULART, VIVIANE P.; CORREA, LUCIANA; PEREIRA, THIAGO M.; ZEZELL, DENISE M.
Nonmelanoma skin cancers represent 95% of cutaneous neoplasms. Among them, squamous cell carcinoma (SCC) is the more aggressive form and shows a pattern of possible metastatic profile. In this work, we used Fourier transform infrared spectroscopy (FTIR) spectroscopy to assess the biochemical changes in normal skin caused by squamous cell carcinoma induced by multi-stage chemical carcinogenesis in mice. Changes in the absorption intensities and shifts were observed in the vibrational modes associated to proteins, indicating changes in secondary conformation in the neoplastic tissue. Hierarchical cluster analysis was performed to evaluate the potential of the technique to differentiate the spectra of neoplastic and normal skin tissue, so that the accuracy obtained for this classification was 86.4%. In this sense, attenuated total reflection (ATR)-FTIR spectroscopy provides a useful tool to complement histopathological analysis in the clinical routine for the diagnosis of cutaneous squamous cell carcinoma.
Non-invasive monitoring of PDT on skin squamous cell carcinoma using the optical attenuation coefficient measured by OCT
2014 - GOULART, VIVIANE P.; SANTOS, MOISES O. dos; CORREA, LUCIANA; LATRIVE, ANNE; LIMA, CASSIO A. de; ZEZELL, DENISE M.
Effects of Nd:YAG laser and professional fluoride application on chemical changes of enamel and its influence on caries prevention
2009 - ANA, P.A.; GOULART, V.P.; ALBERTO, F.G.; TABCHOURY, C.P.M.; CURY, J.A.; ZEZELL, D.M.