Susceptibilities of the dermatophytes Trichophyton mentagrophytes and T. rubrum microconidia to photodynamic antimicrobial chemotherapy with novel phenothiazinium photosensitizers and red light

Photodynamic antimicrobial chemotherapy (PACT) is a promising alternative to conventional chemotherapy that can be used to treat localized mycosis. The development of PACT depends on identifying effective and selective PS for the different pathogenic species. The in vitro susceptibilities of Trichophyton mentagrophytes and Trichophyton rubrum microconidia to PACT with methylene blue (MB), toluidine blue o (TBO), new methylene blue N (NMBN), and the novel pentacyclic phenothiazinium photosensitizer S137 were investigated. The efficacy of each PS was determined based on its minimal inhibitory concentration (MIC). Additionally, we evaluated the effect of PACT with NMBN and S137 on the survival of the microconidia of both species. 5137 showed the lowest MIC. MIC for S137 was 2.5 mu M both for T. mentagrophytes and T. rubrum, when a light dose of 5J cm(-2) was used. PACT with NMBN (10 mu M and 20J cm(-2)) resulted in a reduction of 4 logs in the survival of the T. rubrum and no survivor of T. mentagrophytes was observed. PACT with S137 at 1 mu M and 20J cm(-2) resulted in a reduction of approximately 3 logs in the survival of both species. When a S137 concentration of 10 mu M was used, no survivor was observed for both species at all light doses (5, 10 and 20J cm(-2)). (C) 2012 Elsevier B.V. All rights reserved.

Clinical, histopathological and immunohistochemical assessment of human skin field cancerization before and after photodynamic therapy

Background The field cancerization concept in photodamaged patients suggests that the entire sun-exposed surface of the skin has an increased risk for the development of (pre)-malignant lesions, mainly epithelial tumours. Topical photodynamic therapy (PDT) is a noninvasive therapeutic method for multiple actinic keratosis (AK) with excellent outcome. Objectives To evaluate the clinical, histological and immunohistochemical changes in human skin with field cancerization after multiple sessions of PDT with methyl-aminolaevulinate (MAL). Methods Twenty-six patients with photodamaged skin and multiple AK on the face received three consecutive sessions of MAL-PDT with red light (37 J cm(-2)), 1 month apart. Biopsies before and 3 months after the last treatment session were taken from normal-appearing skin on the field-cancerized area. Immunohistochemical stainings were performed for TP-53, procollagen-I, metalloproteinase-1 (MMP-1) and tenascin-C (Tn-C). Results All 26 patients completed the study. The global score for photodamage improved considerably in all patients (P < 0.001). The AK clearance rate was 89.5% at the end of the study. Two treatment sessions were as effective as three MAL-PDT sessions. A significant decrease in atypia grade and extent of keratinocyte atypia was observed histologically (P < 0.001). Also, a significant increase in collagen deposition (P = 0.001) and improvement of solar elastosis (P = 0.002) were noticed after PDT. However, immunohistochemistry showed only a trend for decreased TP-53 expression (not significant), increased procollagen-I and MMP-1 expressions (not significant) and an increased expression of Tn-C (P = 0.024). Conclusions Clinical and histological improvement in field cancerization after multiple sessions of MAL-PDT is proven. The decrease in severity and extent of keratinocyte atypia associated with a decreased expression of TP-53 suggest a reduced carcinogenic potential of the sun-damaged area. The significant increase of new collagen deposition and the reduction of solar elastosis explain the clinical improvement of photodamaged skin.

A randomised clinical trial of the effect of low-level laser therapy for perineal pain and healing after episiotomy: A pilot study

Objective: to evaluate the effects of low-level laser therapy for perineal pain and healing after episiotomy. Design: a double-blind, randomised, controlled clinical trial comparing perineal pain scores and episiotomy healing in women treated with low-level laser therapy (LLLT) and with the simulation of the treatment. Setting: the study was conducted in the Birth Centre and rooming-in units of Amparo Maternal, a maternity service located in the city of Sao Paulo, Brazil. Participants: fifty-two postpartum women who had had mediolateral episiotomies during their first normal delivery were randomly divided into two groups of 26: an experimental group and a control group. Intervention: in the experimental group, the women were treated with LLLT. Irradiation was applied at three points directly on the episiotomy after the suture and in three postpartum sessions: up to 2 hrs postpartum, between 20 and 24 hrs postpartum and between 40 and 48 hrs postpartum. The LLLT was performed with diode laser, with a wavelength of 660 nm (red light), spot size of 0.04 cm(2), energy density of 3.8 J/cm(2), radiant power of 15 mW and 10 s per point, which resulted in an energy of 0.15 J per point and a total energy of 0.45 J per session. The control group participants also underwent three treatment sessions, but without the emission of radiation (simulation group), to assess the possible effects of placebo treatment. Main outcomes: perineal pain scores, rated on a scale from 0 to 10, were evaluated before and immediately after the irradiation in the three sessions. The healing process was assessed using the REEDA scale (Redness, Edema, Echymosis, Discharge Aproximation) before each laser therapy session and 15 and 20 days after the women's discharge. Findings: comparing the pain scores before and after the LLLT sessions, the experimental group presented a significant within-group reduction in mean pain scores after the second and third sessions (p=0.003 and p<0.001, respectively), and the control group showed a significant reduction after the first treatment simulation (p=0.043). However, the comparison of the perineal pain scores between the experimental and control groups indicated no statistical difference at any of the evaluated time points. There was no significant difference in perineal healing scores between the groups. All postpartum women approved of the low-level laser therapy. Conclusions: this pilot study showed that LLLT did not accelerate episiotomy healing. Although there was a reduction in perineal pain mean scores in the experimental group, we cannot conclude that the laser relieved perineal pain. This study led to the suggestion of a new research proposal involving another irradiation protocol to evaluate LLLT's effect on perineal pain relief. (C) 2011 Elsevier Ltd. All rights reserved.

Previous illumination of a water soluble chlorine photosensitizer increases its cytotoxicity

Photodithazine (PDZ) is an N-methyl-D-glucosamine derivative of chlorine e6 that is water soluble and has an intense absorption in the range of 650-680 nm. PDZ photobleaching and photoproduct formation were induced by illumination with laser at two wavelengths: 514 nm (ion argon laser) as well as in 630 nm (dye laser). The time constants of PDZ photobleaching were: 18 min for 630 nm irradiation and 50 min for 514 nm irradiation, suggesting that degradation after irradiation with red light is faster than with green light. Photoproducts formation was evidenced by the appearance of a new absorption band at 668 nm with slight broaden of the Soret band, suggesting that there was no break of the macrocycle. The cytotoxicity of the photodegradated PDZ was investigated and showed to be lower in the dark and higher than non irradiated PDZ. These results may have important clinical implications for PDT such as the possibility to use the previously irradiated PDZ just before clinical application in order to get increased efficiency.

Safety assessment of oral photodynamic therapy in rats

Photodynamic therapy (PDT) is based on the synergism of a photosensitive drug (a photosensitizer) and visible light to destroy target cells (e.g., malignant, premalignant, or bacterial cells). The aim of this study was to investigate the response of normal rat tongue mucosa to PDT following the topical application of hematoporphyrin derivative (Photogem®), Photodithazine®, methylene blue (MB), and poly(lactic-co-glycolic acid) (PLGA) nanoparticles loaded with MB. One hundred and thirty three rats were randomly divided in various groups: the PDT groups were treated with the photosensitizers for 10 min followed by exposure to red light. Those in control groups received neither photosensitizer nor light, and they were subjected to light exposure alone or to photosensitizer alone. Fluorescent signals were obtained from tongue tissue immediately after the topical application of photosensitizers and 24 h following PDT. Histological changes were evaluated at baseline and at 1, 3, 7, and 15 days post-PDT treatment. Fluorescence was detected immediately after the application of the photosensitizers, but not 24 h following PDT. Histology revealed intact mucosa in all experimental groups at all evaluation time points. The results suggest that there is a therapeutic window where PDT with Photogem®, Photodithazine®, MB, and MB-loaded PLGA nanoparticles could safely target oral pathogenic bacteria without damaging normal oral tissue.

Red and infrared light distribution in blood.

Low level laser therapy (LLLT) is used in several applications, including the reduction of inflammatory processes. It might be used to prevent the systemic inflammatory response syndrome (SIRS), which some patients develop after cardiopulmonary bypass (CPB) surgery. The objectives of this study were to investigate light distribution inside blood, in order to implement the LLLT during CPB, and, through this study, to determine the best wavelength and the best way to perform the treatment. The blood, diluted to the same conditions of CPB procedure was contained inside a cuvette and an optical fiber was used to collect the scattered light. Two wavelengths were used: 632.8 nm and 820 nm. Light distribution in blood inside CPB tubes was also evaluated. Compared to the 820 nm light, the 632.8 nm light is scattered further away from the laser beam, turning it possible that a bigger volume of blood be treated. The blood should be illuminated through the smallest diameter CPB tube, using at least four distinct points around it, in only one cross section, because the blood is kept passing through the tube all the time and the whole volume will be illuminated.

Influence of temperature, light and nutrients on the growth rates of the macroalga Gracilaria domingensis in synthetic seawater using experimental design

In the present study, the daily relative growth rates (DRGR, in percent per day) of the red macroalga Gracilaria domingensis in synthetic seawater was investigated for the combined influence of five factors, i.e., light (L), temperature (T), nitrate (N), phosphate (P), and molybdate (M), using a statistical design method. The ranges of the experimental cultivation conditions were T, 18-26A degrees C; L, 74-162 mu mol photons m(-2) s(-1); N, 40-80 mu mol L-1; P, 8-16 mu mol L-1; and M, 1-5 nmol L-1. The optimal conditions, which resulted in a maximum growth rate of a parts per thousand yen6.4% d(-1) from 7 to 10 days of cultivation, were determined by analysis of variance (ANOVA) multivariate factorial analysis (with a 2(5) full factorial design) to be L, 74 mu mol photons m(-2) s(-1); T, 26A degrees C; N, 80 mu mol L-1; P, 8 mu mol L-1; and M, 1 nmol L-1. In additional, these growth rate values are close to the growth rate values in natural medium (von Stosch medium), i.e., 6.5-7.0% d(-1). The results analyzed by the ANOVA indicate that the factors N and T are highly significant linear terms, X (L), (alpha = 0.05). On the other hand, the only significant quadratic term (X (Q)) was that for L. Statistically significant interactions between two different factors were found between T vs. L and N vs. T. Finally, a two-way (linear/quadratic interaction) model provided a quite reasonable correlation between the experimental and predicted DRGR values (R (adjusted) (2) = 0.9540).

Broad combined orange-red emissions from Eu2+- and Eu3+-doped low-silica calcium aluminosilicate glass

In this paper, a broad combined orange-red emission from Eu2+- and Eu3+-doped low-silica calcium aluminosilicate (LSCAS) glass is reported. Spectroscopic results demonstrate that it is possible to tune the emission wavelength by changing the excitation wavelength in the UV-Vis region. The color coordinates for the emission spectra were calculated, and using the Commission Internationale de l'Eclairage 1931 and 1976 chromatic diagrams, it is possible to note that they are dependent on the excitation wavelength. In addition, the (u', v') color coordinates for the investigated LSCAS samples are close to the Planckian spectrum in the cold region between 2000 and 2600K. Our results show that the Eu:LSCAS system can be used in a white light phosphor when mixed in aggregate with phosphors using green-yellow luminescent ions. (c) 2012 Optical Society of America

Very Intense Distinct Blue and Red Photoluminescence Emission in MgTiO3 Thin Films Prepared by the Polymeric Precursor Method: An Experimental and Theoretical Approach

MgTiO3 (MTO) thin films were prepared by the polymeric precursor method with posterior spin-coating deposition. The films were deposited on Pt(111)/Ti/SiO2/Si(100) substrates and heat treated at 350 degrees C for 2 h and then heat treated at 400, 450, 500, 550, 600, 650 and 700 C for 2 h. The degree of structural order disorder, optical properties, and morphology of the MTO thin films were investigated by X-ray diffraction (XRD), micro-Raman spectroscopy (MR), ultraviolet-visible (UV-vis) absorption spectroscopy, photoluminescence (PL) measurements, and field-emission gun scanning electron microscopy (FEG-SEM) to investigate the morphology. XRD revealed that an increase in the annealing temperature resulted in a structural organization of MTO thin films. First-principles quantum mechanical calculations based on density functional theory (B3LYP level) were employed to study the electronic structure of ordered and disordered asymmetric models. The electronic properties were analyzed, and the relevance of the present theoretical and experimental results was discussed in the light of PL behavior. The presence of localized electronic levels and a charge gradient in the band gap due to a break in the symmetry are responsible for the PL in disordered MTO lattice.