Publications by authors named "Michelle Barreto Requena"

Significance: Response rates evaluation of photodynamic therapy (PDT) for nodular basal cell carcinoma (BCC) treatment located on high-risk and low-risk areas of the face.

Approach: Two groups of nodular BCC were selected, debulked, and received 20% methyl aminolevulinate (MAL) hydrochloride cream. After 3 h, the first irradiation was performed (20 min, 150 J/cm).

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Photodynamic therapy (PDT) has been used worldwide as a non-surgical option for the treatment of basal cell carcinoma (BCC). PDT treatment for pigmented BCC is not frequently performed because of poorer results, which are explained by lower penetration of the light, possibly related to the melanin absorption in the visible range wavelengths. However, there is evidence for an increase in PDT cure rates with prior debulking of the lesion.

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Melanoma is the most aggressive type of skin cancer and a relevant health problem due to its poor treatment response with high morbidity and mortality rates. This study, aimed to investigate the tissue changes of an improved photodynamic therapy (PDT) response when combined with optical clearing agent (OCA) in the treatment of cutaneous melanoma in mice. Photodithazine (PDZ) was administered intraperitoneally and a solution of OCA was topically applied before PDT irradiation.

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One important limitation of topical photodynamic therapy (PDT) is the limited tissue penetration of precursors. Microneedles (MNs) are minimally invasive devices used to promote intradermal drug delivery. Dissolving MNs contain drug-associated to polymer blends, dissolving after insertion into skin, allowing drug release.

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Photodynamic procedures have been used in many applications, ranging from cancer treatment to microorganism inactivation. Photodynamic reactions start with the activation of a photosensitizing molecule with light, leading to the production of cytotoxic molecules that promote cell death. However, establishing the correct light and photosensitizer dosimetry for a broadband light source remains challenging.

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The combination of multiple sessions of Photodynamic therapy (PDT) and surgery have been used to treat an extensive superficial lesion of squamous cell carcinoma in situ. Methyl aminolevulinate (MAL) mediated PDT was applied to reduce the tumoral area and a small surgical removal was performed to complete elimination of the lesion. The reduction of the tumor area avoided the need for a skin graft application as well as possible postoperative complications, offering a more favorable cosmetic outcome.

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The limited adoption of photodynamic therapy (PDT) around the medical field may be tied to the unpredicted treatment response that an unmonitored therapy could deliver. Given the high variability in the lesions optical and physiological parameters, it is of fundamental importance to monitor PDT, since different lesions require different therapeutic parameters. We developed a system to treat and online monitor PDT of skin cancer, using protoporphyrin-IX (PpIX) near-infrared fluorescence imaging.

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Background: Photodynamic Therapy (PDT) is a treatment for non-melanoma skin cancer. One of the main challenges of topical PDT is to increase the precursor penetration when applied on the lesion. Protoporphyrin IX (PpIX) is an endogenous photosensitizer (PS) widely used, obtained by the administration of precursors such as aminolevulinic acid and methyl aminolevulinate.

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Along the past years, a national program to implement photodynamic therapy (PDT) for nonmelanoma skin cancer (NMSC) was performed over the Brazilian territory. Using a strategy involving companies, national bank, and medical partners, equipment, medication, and protocols were tested in a multicenter study. With results collected over 6 years, we could reach a great deal of advances concerning the use of PDT for skin cancer.

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In order to purposely decrease the time of the photodynamic therapy (PDT) sessions, this study evaluated the effects of PDT using topical and intradermal delivery of two protoporphyrin (PpIX) precursors with intense pulsed light (IPL) as irradiation source. This study was performed on porcine skin model, using an IPL commercial device (Intense Pulse Light, HKS801). IPL effect on different administration methods of two PpIX precursors (ALA and MAL) was investigated: a topical cream application and an intradermal application using a needle-free, high-pressure injection system.

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Background: Photodynamic Therapy (PDT) using Aminolevulinic acid (ALA) and derivative molecules as topical medication and as a precursor of protoporphyrin (PPIX), is limited due to low permeation through skin or efficiency in porphyrin production. This behavior affects the production and homogeneity of PPIX distribution on superficial skin and in the deeper skin layers. Many authors propose alternatives to solve this such as, modification in the ALA and derivativemolecules, modifying the chemical properties of emulsion external phase or incorporating a delivery system to the emulsion.

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Objective: The goal of this study is to demonstrate an alternative procedure to perform topical photodynamic therapy (PDT). Here, we propose the combined use of negative pressure and a 5-Aminolevulinic acid (5-ALA) cream occlusion to increase protoporphyrin IX (PPIX) formation.

Background Data: PDT using topical 5-ALA as a prodrug and precursor of PPIX has been used in the treatment and diagnosis of different types of cancer and skin diseases.

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