Cristina Kurachi

Photodiagnosis and treatment of condyloma acuminatum using 5-aminolevulinic acid and homemade devices.

BACKGROUNDnThe objective of this study was to improve the feasibility of applying topic 5-aminolevulinic acid (ALA) in photodiagnosis (PD) and treatment of condyloma caused by human papillomavirus (HPV) using two homemade handheld devices and to discuss the photodynamic therapy (PDT) as a suitable alternative for each of the cases studied. Both, protoporphyrin IX production and photodegradation were analyzed, and the pain experienced during the illumination was correlated with the light intensities.nnnMETHODSnA total of 40 women with different grades of lesions caused by HPV were chosen from patients of the School of Medicine of Ribeirão Preto (University of Sao Paulo) and of the Unit of Public Health of Araraquara, Sao Paulo.nnnRESULTSnWe did not encounter any unexpected difficulties using our devices during the treatment. The existence of an easily observable reddish fluorescence with large intensity concentrated on the lesions is the clinical indication of the penetration and the selective concentration of protoporphyrin IX in the clinical and subclinical lesions rather than in the healthy tissue. The aesthetic results were much better than those obtained by conventional techniques as surgery or cryogenics, with no recurrence reported after two years of treatment.nnnCONCLUSIONSnOur results are proof for the various advantages using ALA cream for the PD and PDT in many different cases of condyloma by HPV. This study will be continued to investigate the PpIX photobleaching and the irradiance and fluence rate to optimize conducting the clinical trials, to improve the devices and therefore increase the treatment response.

Comparative study in vitro of microleakage in class V cavity preparation with and without Er:YAG laser

The evaluation of microleakage is a method conventionally used to evaluate the composite restoration in cavities prepared by laser or conventional drill. The samples were five sound molar human extracted teeth with cavity preparation Class V in each surface (buccal, lingual, mesial and distal) divided in: GI -- cavity preparation with Er:YAG laser, adhesive agent Single Bond (3M), composite Z100 (3M) color A2; GII -- cavity preparation laser, 35% phosphoric acid etching, adhesive, composite; GIII -- cavity preparation with a drill, adhesive, composite; GIV -- cavity preparation with a drill, acid etching, adhesive, composite. The samples were sealed with a coating of nail varnish except on the area of the restoration and immersed in 50% aqueous solution of silver nitrate for 24 hours while kept in darkness. Samples were rinsed, soaked in photorevealing solution and exposed to fluorescent light for 6 hours. After, they were embedded in epoxy resin and sectioned longitudinally using the diamond saw microtone under running water. The specimens were observed under optical microscopy and the results were analyzed under Kruskall Wallis resulting in difference statistically between GI X GIV at the 5% level; and under Mann-Whitney resulting non-difference statistically between groups divided in cervical or occlusal walls.

Photodynamic Therapy for Non-Melanoma Skin Cancer

Treatments such as surgical excision, cryotherapy, topical application of imiquimod cream and 5-fluorouracil cream, and radiotherapy are commonly chosen based on the depth and exten‐ sion of the lesions. Limitations and side-effects of the conventional therapies motivate the development of other techniques. Photodynamic therapy (PDT) is presented as an alternative treatment for basal cell carcinoma (BCC).

Viability for the conjugate use of Electrosurgery and Photodynamic Therapy

Photodynamic Therapy (PDT) is a technique for destroying tumor cells with little harm to surrounding healthy tissue. However, the light wavelength has limited penetration in the tissue, making the association of a surgical procedure needed for larger lesions. Electrosurgery (ES) is a recommended excision technique, but the optical properties of the tissue damaged by ES and its influence on PDT procedure are unknown. Twelve rats (Wistar) composed the animal model of four groups (ES, PDT, ES+PS+Light, PS+ES+Light), evaluating different orders of conjugation via fluorescence, imaging and necrosis depth. First histopathological analysis has shown a highly modified surface of tissue (integral structure loss and dehydration shrinkage), protein denaturation, accompanied by bleeding and inflammatory damage. Fluorescence imaging showed strong scattering of light at the surface of modified tissue, which may cause higher losses of light on the surface. Fluorescence spectra showed different photosensitizer emissions for distinct operation modes. The different tissue composition can also induce changes on absorption and scattering properties, influencing the light penetration. The study showed significant necrosis formation beyond the limits of electrosurgery damage, making possible the conjugate use of ES and PDT.

Effects of Infrared-LED Illumination Associated with Treadmill Training on Biomechanical Parameters in Post Menopausal Women

The objective of this study was to investigate the effects of infrared-LED illumination (850nm) associated with treadmill training on biomechanical parameters (power, work and fatigue of quadriceps muscle) in post menopausal women.

Improvement of the light-tissue coupling for better outcome of phototherapies

Phototherapies have been increasingly used in several applications such as the control of pain and inflammatory processes, photodynamic therapy, and even aesthetics uses. After many decades, the dosimetry for those techniques remains challenging. One of the key issues is the lack of homogeneity obtained for tissue illumination, which may limit adequate treatment. Especially concerning lesions, the surface tissue is usually irregular, and the light does not couple to the tissue efficiently to promote an effective treatment. A series of experiments have been performed using optical phantoms, in which coupling was improved by introducing a gel with a low concentration of scattering agents between the fiber and the phantom as an attempt to improve the homogeneity of light distribution within the phantoms. The effects promoted by roughness on phantom tissue surfaces are considerably attenuated when the coupling gel was introduced, resulting in a more uniform illumination pattern that may be used to promote better phototherapy treatments outcome.

Subcellular localization and photodynamic activity of Photodithazine (glucosamine salt of chlorin e6) in murine melanoma B16-F10: an in vitro and in vivo study

Photodynamic therapy (PDT) is already a good option for the clinical treatment of several lesions, including mainly nonmelanoma skin cancers. However, cutaneous melanoma treatment remains a challenge when using PDT. One of the reasons for its reduced efficacy is the high pigmentation of melanoma cells. The object of our study is to evaluate the feasibility of the Photodithazine as a photosensitizer for melanoma. Photodithazine is already used in some malignant tumors with satisfactory results and has significant absorption band around 660 nm where the absorption of melanin is low. In this study, we measured the subcellular localization and photodynamic activity of Photodithazine (PDZ) in murine melanoma B16-F10 cell culture. Additionally, a PDT procedure was applied in an animal melanoma model. This first result demonstrates that Photodithazine is more localized at mitochondria in B16F10 cell culture and the cell viability is reduced to less than 90% using 1 µg/mL (PDZ) and 2 J/cm2. We also noticed a rapid PDZ (less than one hour) accumulation in a murine melanoma model. The treatment of melanoma resulted in 20 % more animal survival after one session of PDT compared with the control group. More studies are required to evaluate the cytotoxic effects of Photodithazine at human melanoma.

Low-dose PDT on breast cancer spheroids

Photodynamic therapy (PDT) has been investigated in clinical studies as a treatment method for breast cancer chest wall recurrences. Complete response percentage in these studies is not 100% in most patients, indicating the presence of a remaining tumor after PDT. Some in vitro studies show that tumor cells present distinct threshold dose, suggesting that the remaining tumor in vivo could require higher doses or different PDT strategies. There is still a lot of controversy of the multiple PDT sessions effect on bulky tumors. The purpose of this study is to investigate low-dose PDT parameters in 3D cultures of breast cancer cells grown by the magnetic levitation method. PDT was performed with Photodithazine® (PDZ) and LED irradiation at 660 nm. Two concentrations of PDZ were investigated and the 50 μg/mL concentration, which showed a superficial distribution, was used in the PDT. Partial damage was observed in the tumors and the viability test showed a small percentage of cell death. This outcome is favorable for the investigation of PDT effects in the remaining tumor. Multiple PDT sections could provide more noticeable alterations in cell morphology and metabolism.

PDI using nebulized indocyanine green for pneumonia treatment

Infectious pneumonia is a major cause of morbidity/mortality, mainly due to the increasing rate of microorganisms resistant to antibiotics. Photodynamic Inactivation (PDI) is emerging as a promising treatment option, which effects are based on oxidative stress, targeting several biomolecules and probably preventing potential resistant strains. In previous studies, the in vitro inactivation of Streptococcus pneumoniae using indocyanine green (ICG) and infrared (IR) light source (780 nm) was successful, and achieving satisfactory reduction of colony-forming units (CFU/mL). In the present study, a proof-of-principle protocol was designed to treat lung infections by PDI using extracorporeal irradiation with a 780 nm laser device and nebulized ICG as photosensitizer. Balb/c mice were infected with S. pneumoniae and PDI was performed two days after infection using 800 μM of nebulized ICG and extracorporeal irradiation. Our results indicate that IR-extracorporeal PDI using nebulized ICG may be considered a potential pneumonia treatment, and pulmonary decontamination with PDI may be used as a single therapy or as an adjuvant for antibiotics.

Assessment of oxidative stress and metabolic rates in liver grafts using time-resolved fluorescence spectroscopy

One of the most relevant postoperative problems in liver transplantation is the initial graft dysfunction, which is generated by the oxidative stress due to ischemia and/or reperfusion. This leads to ischemia-reperfusion injury of the transplanted organ. This injury can be severe and, when the primary graft is nonfunctional, an urgent retransplantation is required. In this context, tools to monitor the oxidative stress in liver grafts would improve the surgical decision-making for transplantation, increasing its success rate. In this study, we evaluated the potential of time-resolved fluorescence spectroscopy to measure oxidative stress in liver grafts before transplantation. This was performed in livers after ischemia and reperfusion kept in 0 °C (control group) and or 20 °C (ischemia-reperfusion injury group). Both fluorescence spectra and lifetimes were monitored immediately, each 1 hour for the first 12 hours, and at 24 hours after the removal of the liver. The hepatic tissue was excited by lasers emitting in 378 nm and 445 nm for investigation of possible metabolic rates associated to NAD(P)H, FAD, lipopigments, and lipofuscin molecules. The fluorescence decay curves were fitted to the convolution between the instrument response function with a bi-exponential decay for 378 nm and a tri-exponential decay for 445 nm by using the SPCImage software. For both excitation wavelengths, the relative weights for the first exponential component decreased faster as a function of time for the ischemia-reperfusion injury group compared to the control group. This suggests time-resolved spectroscopy is a promising technique to help clinicians to make decisions before liver transplantation.