A new photodynamic therapy protocol for nodular basal cell carcinoma treatment: Effectiveness and long-term follow-up.

BACKGROUND: Photodynamic therapy (PDT) has been reported as an excellent option for the treatment of small nodular basal cell carcinomas (nBCC). The standard protocol consists of two sessions, one week apart. Sometimes, returning to the hospital after one week can be impractical for elderly patients, due to comorbidities and mobility issues. Therefore, a new technique performed in one day could be superior for those patients. OBJECTIVE: Evaluate the effectiveness of a PDT Single-visit protocol comparing to the standard protocol, as well as pain and long-term recurrence-free follow-up for nBCC. METHODS: A total of 120 nBCC were treated through a Standard PDT protocol(two sessions, one week apart), and 120 nBCC were treated through a Single-visit PDT(two sessions in one day). A 30-day-after biopsy was performed in order to evaluate the results after the treatment. The lesions that had successful treatment were clinically and dermoscopically evaluated every 6 months up to 60 months. The pain score was compared between the groups(assessed every 3 min during PDT). RESULTS: A complete response at 30-days-after PDT biopsy was observed in 85% of Standard PDT and in 93.3% of Single-visit PDT. Regarding the pain during the illumination, less pain was observed during the second session of the Single-visit PDT. The recurrence-free follow up showed, after 60 months, an 69.0% cumulative probability of recurrence-free for Standard PDT and 80.6% for Single-visit PDT. CONCLUSIONS: The suggested Single-visit PDT protocol resulted in better outcomes at 30-day-after PDT biopsy and in lower recurrence rates than the Standard PDT protocol. A more comfortable and more efficient treatment was offered for the patients, with lower pain.

High power Q-switched 1064 nm / 532 nm Nd:YAG Laser in tattoo removal: A systematic review.

Q-switched 1064 nm/532 nm Nd: YAG Lasers present important characteristics which can contribute toward the removal of tattoos, for having the ability to reach only specific targets with minimal damage to the tissue. Despite reports of their clinical benefits, only a few scientific studies demonstrate the efficacy and safety of these types of lasers in the short and long term. To substantiate the effects, benefits, and safety of the application of Q-switched 1064 nm/532 nm Nd: YAG lasers, a systematic review was carried out from September to December of 2019, about the studies which report their use in the removal of tattoos, published in the last 20 years. Randomized clinical trials in humans were considered, as long as they evaluated the efficacy, safety, and benefits of the application of Q-switched 1064 nm/532 nm Nd: YAG lasers in the removal of black and color tattoos in different skin phototypes. One hundred and twenty-two articles were identified after the titles, abstracts were read, and duplicates were removed; six articles were left, which were included in the research (188 individuals). The Q-switched 1064 nm/532 nm Nd: YAG lasers seem promising in the short term, with minimal adverse effects; however, the efficacy and safety in the long term still present limitations. Consequently, future research is necessary, with better methodological standardization applied and with a follow-up for a longer period of evaluation of possible permanent adverse effects, to determine the standardization and safety of the therapy with the lasers Nd: YAG de 1064 nm/532 nm Q-switched.

A pilot study on the effects of transcutaneous and transmucosal laser irradiation on blood pressure, glucose and cholesterol in women.

The present pilot study had the objective to determine the effects of transcutaneous and transmucosal laser irradiation on arterial blood pressure (ABP), glucose (Glu) triglycerides (Tg), total cholesterol (Ch), high-density level cholesterol (HDL) and low-density cholesterol (LDL) immediately after treatment (T0) and after 30 (T30) and 60 (T60) days. Patients (n = 36) were selected and randomly distributed into 6 groups (n = 6/group; [G1] negative control, [G2] radial artery transcutaneous laser irradiation [G3] radial artery transcutaneous irradiation, [G4] transmucosal sublingual irradiation, [G5] transmucosal intra-nasal irradiation and [G6] extended radial artery transcutaneous irradiation). Blood exams were performed at T0, T30 and T60. Systolic and diastolic pressure results have indicated that patients' pressures ranged from 90 mmHg (P22, T30, G4) to 189 mmHg (P16, T0, G3) and 54 mmHg (P21, T60, G4) to 175 mmHg (P16, T30, G3). Levels of Glu at T30 and T60 varied from 5.53% (G1) to -5.78% (G6) and 1.21 (G2) to -8.69 (G6), respectively. Data was statistically assessed for normality and homogeneity of variances using the F-statistic and Bartlett's tests. Significant differences were determined using One-Way ANOVA and Fischer post hoc tests. Results indicated that treatments investigated can be safely used as an adjunct method to regulate blood pressure, glucose, triglycerides and cholesterol.

Efficacy, safety, and guidelines of application of the fractional ablative laser erbium YAG 2940 nm and non-ablative laser erbium glass in rejuvenation, skin spots, and acne in different skin phototypes: a systematic review.

Non-ablative and ablative fractional erbium lasers are among the most frequently used resources in dermatology for facial rejuvenation and for treating dermatological disorders. This type of erbium laser can be found at wavelengths of 1540 or 1550 nm, which are classified as non-ablative erbium glass, and at 2940 nm, classified as ablative erbium YAG. Despite the reports of their clinical benefits, few scientific studies have demonstrated the efficacy and safety of these lasers in the short or long term. In order to substantiate the effects, benefits, and safety of applying the erbium glass and erbium YAG lasers, a systematic review was carried out from August to December 2019 about studies published in the last 20 years. Randomized clinical trials in humans were considered that evaluated the efficacy, safety, and benefits of applying the fractional lasers erbium glass and erbium YAG to facial rejuvenation, skin spots, and atrophic acne scars. A total of 338 articles were identified; 76 articles remained after their titles and abstracts were read, and 42 articles were selected after removing the duplicates. After the articles were read in full, 17 of these articles were included in the systematic review (453 patients). The erbium glass and erbium YAG lasers seem promising in the short term, with minimal adverse effects; however, the long-term efficacy and safety still present limitations. Consequently, future research is needed, with better methodological standardization and a follow-up with a longer evaluation period for possible permanent adverse effects to determine the standardization and safety of therapy with erbium glass and erbium YAG lasers.

Photodynamic therapy dosimetry using multiexcitation multiemission wavelength: toward real-time prediction of treatment outcome.

Evaluating the optical properties of biological tissues is needed to achieve accurate dosimetry during photodynamic therapy (PDT). Currently, accurate assessment of the photosensitizer (PS) concentration by fluorescence measurements during PDT is typically hindered by the lack of information about tissue optical properties. In the present work, a hand-held fiber-optic probe instrument monitoring fluorescence and reflectance is used for assessing blood volume, reduced scattering coefficient, and PS concentration facilitating accurate dosimetry for PDT. System validation was carried out on tissue phantoms using nonlinear least squares support machine regression analysis. It showed a high correlation coefficient (>0.99) in the prediction of the PS concentration upon a large variety of phantom optical properties. In vivo measurements were conducted in a PDT chlorine e6 dose escalating trial involving 36 male Swiss mice with Ehrlich solid tumors in which fluences of 5, 15, and 40 J cm - 2 were delivered at two fluence rates (100 and 40 mW cm - 2). Remarkably, quantitative measurement of fluorophore concentration was achieved in the in vivo experiment. Diffuse reflectance spectroscopy (DRS) system was also used to independently measure the physiological properties of the target tissues for result comparisons. Then, blood volume and scattering coefficient measured by the fiber-optic probe system were compared with the corresponding result measured by DRS and showed agreement. Additionally, tumor hemoglobin oxygen saturation was measured using the DRS system. Overall, the system is capable of assessing the implicit photodynamic dose to predict the PDT outcome.

Effects of multi-directional oscillatory vibration in the treatment of cellulite and body remodeling / Efeitos da terapia vibro-oscilatória multidirecional no tratamento da celulite e remodelamento corporal

Abstract Introduction: Several technologies have been developed and optimized for the treatment of unaesthetic disorders. Among them is the oscillatory vibration therapy, a novel form of treatment based on the mechanical and physiological fundamentals of the vibration platform. Objective: The present study evaluated the efficacy of the oscillatory vibration therapy in the improvement of body contour remodeling and in the aspect of cellulite in women. Methods: This is a prospective longitudinal comparative study, in which the following evaluation tools are used: anthropometry, perimetry, adipometry, evaluation of skin viscoelasticity with Cutometer®, evaluation of the thickness of the hypodermis with diagnostic ultrasound and analysis of severity of cellulite (CSS). The evaluations occurred at the start and 1 week after the end of ten oscillatory vibration therapy. The results were analyzing using a paired student's t-test with interval confidence of 95% (PValue <0.05). Results: Thirty women took part in the research, with age of 33 ± 9 years, weight of 62 ± 11 kg, height of 1.66 ± 0.06 m, BMI of 22 ± 2 kg/m2. The measurements of perimetry, adipometry, analysis of subcutaneous tissue thickness by means of diagnostic ultrasound and analysis of skin viscoelasticity did not present significant alterations. However, the CSS variable of the right gluteus (7.3 ± 1.8 to 5.8 ± 1.6 ≤ 0.0001), left gluteus (7.2 ± 1.9 to 5.8 ± 1.6= 0.0001), right thigh (6.9 ± 1.9 to 5.6 ± 1.4 = 0.0004), left thigh (6.9 ± 1.9 to 5.6 ± 1.3 = 0.0004) and Celluqol® (59 ± 16 to 49 ± 16 = 0.022) presented significant difference. Conclusion: The multi-directional oscillatory vibration therapy is an effective and efficient therapy for the treatment of cellulite; however, for the treatment of body remodeling, it must be further evaluated and studied. (AU)

Introdução: Várias tecnologias vêm sendo desenvolvidas e otimizadas para o tratamento das afecções inestéticas. Dentre elas está a terapia vibro-oscilatória, uma nova forma de tratamento baseada na fundamentação mecânica e fisiológica da plataforma vibratória Objetivo: O presente estudo avaliou a eficácia da terapia vibro-oscilatória para melhora do remodelamento corporal e aspecto de celulite em mulheres. Métodos: Trata-se de um estudo clínico longitudinal prospectivo e comparativo, no qual se utilizaram as seguintes ferramentas de avaliação: antropometria, perímetria, adipometria, avaliação da viscoelasticidade da pele com Cutometer®, avaliação da espessura da hipoderme com ultrassom diagnóstico e análise da escala de severidade da celulite (CSS). As avaliações ocorreram no início e após 1 semana de término das dez sessões da terapia vibro-oscilatória. As análises estatísticas foram realizadas com o software Bioestat 5.0, utilizando o teste de normalidade de Lilliefor (P-valor > 0,05), teste paramétrico e teste T-Student da amostra pareada. Resultados: Trinta mulheres participaram da pesquisa, com média de idade de 33 ± 9 anos, peso médio de 62 ± 11 kg, altura média de 1,66 ± 0,06 metros, IMC médio de 22 ± 2 kg/m2 . As medidas de perímetria, adipometria, análise da espessura do tecido subcutâneo por meio de ultrassom diagnóstico e análise da viscoelasticidade da pele não apresentaram alterações significativas. Entretanto as variáveis de CSS glúteo direito (7,3 ± 1,8 para 5,8 ± 1,6 ≤ 0,0001), glúteo esquerdo (7, 2 ± 1,9 para 5,8 ± 1,6 = 0,0001), coxa direita (6,9 ± 1,9 para 5,6 ± 1,4 = 0,0004), coxa esquerda (6.9 ± 1,9 para 5,6 ± 1,3 = 0,0004) e Celluqol® (59 ± 16 para 49 ± 16 = 0,022), apresentaram diferença significativa. Conclusão: A terapia vibro-oscilatória multidirecional é uma terapia efetiva e eficaz para o tratamento da celulite, porém para o tratamento de remodelamento corporal ela deve ser mais bem avaliada e estudada. (AU)

Efficacy and safety of ND:YAG 1064 nm lasers for photoepilation: a systematic review.

Using light sources in phototherapy has presented promising results regarding several types of facial and body skin affections for centuries. The neodymium-doped yttrium aluminum garnet (ND:YAG) 1064 nm laser has become a standard treatment in dermatology for dermatological disturbances related to the pilous follicle and the structures surrounding it. Despite the reports of its clinical benefits, few scientific studies show its actual safety and efficacy. To substantiate the effects, benefits, and safety of applying an ND:YAG 1064 laser in the epilation process during esthetic treatment, a systematic review was carried out between October 2018 and January 2019, on studies published in the last 20 years. Randomized clinical trials in humans were considered that evaluated the efficacy, safety, and benefits of ND:YAG laser application at 1064 nm wavelengths for hair removal. A total of 198 articles were identified; 58 articles remained after their titles and abstracts were read; and 21 articles were selected after the removal of duplicates. After the integral reading, 13 of these articles were included in the systematic review (734 patients). The ND:YAG 1064 nm laser presents safety and promising, beneficial effects in epilation. However, further scientific studies with better methodologic quality are necessary to better standardize ND:YAG laser therapy and clarify its parameters for photoepilation.

Eficácia da massagem mecânica motorizada associada a cosmecêuticos no remodelamento corporal e aspecto da celulite / Efficacy of motorized mechanical massage associated with derma-cosmeceuticals in body remodeling and aspect of cellulite

Gordura localizada e celulite são as afecções estéticas que mais incomodam as mulheres nos dias atuais e as levam a busca de tratamentos estéticos. Por essa razão, o objetivo do presente estudo foi avaliar a associação da massagem mecânica motorizada com cosmecêuticos no tratamento da gordura localizada e celulite. Métodos: Trata-se de um estudo clínico longitudinal prospectivo e comparativo. Trinta e duas mulheres foram incluídas no presente estudo seguindo os critérios de elegibilidade e inelegibilidade, todos foram avaliados e reavaliados após dez sessões do protocolo de tratamento. Para análise dos dados foram utilizados testes Lilliefor's, teste t-student bicaudal pareado, teste t-student bicaudal para amostras heterocedásticas. Resultados: Trinta mulheres finalizaram o protocolo de tratamento. Obteve-se redução das medidas, de abdome superior (p < 0,032) e abdome inferior (p < 0,004) na adipometria; medidas de cintura (p < 0,008) e abdome inferior (p < 0,022) avaliadas pela perimetria; na análise do ultrassom houve redução da medida de abdome superior (p < 0,004), flancos (p < 0,021), posterior de coxa região de prega glútea (p < 0,006) e posterior de coxa região inferior (p < 0,0001). Conclusão: Diante dos resultados, conclui-se que o protocolo de tratamento com a associação da massagem mecânica motorizada e cosmecêuticos foram eficazes para a melhora do contorno corporal e a aparência da celulite. (AU)

Localized fat and cellulite are the aesthetic conditions which disturb women the most, in current times, and therefore lead them to search esthetic treatments. For this reason, the objective of this study was to evaluate the association of motorized mechanical massage with derma cosmeceuticals in the treatment of localized fat and cellulitis. Methods: This is a clinical prospective longitudinal study. Thirty-two women were included in the present study, following the criteria of eligibility and ineligibility, and they were all evaluated and re-evaluated after ten sessions of the treatment protocol. For data analysis, we used Lilliefors t-student tests, paired two-tailed test, for heteroscedastic samples. Results: Thirty women finalized the treatment protocol, and reduction of measures was obtained in the upper abdomen (p < 0.032) and lower abdomen (p < 0.004) in adipometry; waist measures (p < 0.008) and lower abdomen, (p < 0.022) evaluated by perimetry: in the ultrasound analysis, there was reduction of the upper abdomen measure (p < 0.004), flanks (p < 0.021), upper posterior thigh area (p < 0.006) and posterior thigh distal area (p < 0.0001). Conclusion: We concluded that the treatment protocol with the association of motorized mechanical massage was efficient in the improvement of the body contour and the aspect of cellulitis. (AU)

Effectiveness of the Electromagnetic Shock Wave Therapy in the Treatment of Cellulite.

In the past centuries, the human body was undervalued; nowadays, however, it is overvalued, and thus the manifestation of the dissatisfactions regarding the body has been increasing. Most of the time, these dissatisfactions are related to cellulite, which is most common in women. Its treatment is one of the challenges which encourage the development of new therapeutic modalities, among them the shockwave therapy. Objective. To evaluate the efficacy of ESWT in the treatment of cellulite in gluteus and posterior of thigh. Method. This is a prospective and comparative study, in which volunteer women who attended the criteria of inclusion were selected and who were subjected to 10 sessions of ESWT. The following were performed as an evaluation method: anthropometry, perimetry, skin viscoelasticity with the Cutometer®, thickness of hypodermis with diagnostic ultrasound, analysis of the scale of severity of cellulite (CSS), and quality of life by the Celluqol® questionnaire. The evaluations occurred before the first session (baseline), after 6 and 10 sessions, and during a follow-up of 3 months after the last session. The statistical test applied was the ANOVA one-way with post hoc of Tukey (P-value < 0.05). Results. There was significant improvement (P<0.05) for CSS, for the variable referring to gross elasticity and skin deformation ability evaluated in the Cutometer® and improvement of quality of life represented by Celluqol®. The result was maintained particularly in the follow-up of 3 months after the end of the treatment. Conclusion. The results presented demonstrated the effectiveness and safety of ESWT in the treatment of cellulite and in the decrease of the degrees, improvement of the aspect of the skin, and reestablishment of quality of life. This trial is registered with ClinicalTrials: NCT03275259.

Synergistic effects of Combined Therapy: nonfocused ultrasound plus Aussie current for noninvasive body contouring.

BACKGROUND AND OBJECTIVES: Nowadays, there are several noninvasive technologies being used for improving of body contouring. The objectives of this pilot study were to verify the effectiveness of the Heccus® device, emphasizing the synergism between nonfocused ultrasound plus Aussie current in the improvement of body contour, and to determine if the association of this therapy with whole-body vibration exercises can have additional positive effects in the results of the treatments. SUBJECTS AND METHODS: Twenty healthy women aged 20-40 years participated in the study. Ten patients received Combined Therapy treatment (G1) and the other 10 participants received Combined Therapy with additional vibratory platform treatment (G2). Anthropometric and standardized photography analysis, ultrasonography, cutometry and self-adminestered questionnaires of tolerance and satisfaction levels with the treatment were used. RESULTS: Compared with baseline values, reduction of fat thickness was observed by ultrasonography in the posterior thigh area in the G1 group (P<0.05) and in the buttocks (P<0.05) and the posterior thigh areas (P<0.05) in the G2. All the treated areas in both groups showed reduction in cellulite degree in the buttocks, G1 (P<0.05) and G2 (P<0.05), and in posterior thigh areas, G1 (P<0.05) and G2 (P<0.05). Optimal improvement of skin firmness (G1, P<0.0001; G2, P=0.0034) in the treated areas was observed in both groups. CONCLUSION: We conclude that the synergistic effects of the Combined Therapy (nonfocused ultrasound plus Aussie current) might be a good option with noninvasive body contouring treatment for improving the aspect of the cellulite, skin firmness and localized fat. If used in association with the whole-body vibratory platform, the results can be better, especially in the treatment of localized fat. Further studies with larger sample size should be performed to confirm these results.

Molecular analyses of two bacterial sampling methods in ligature-induced periodontitis in rats.

The prevalence profile of periodontal pathogens in dental plaque can vary as a function of the detection method; however, the sampling technique may also play a role in determining dental plaque microbial profiles. We sought to determine the bacterial composition comparing two sampling methods, one well stablished and a new one proposed here. In this study, a ligature-induced periodontitis model was used in 30 rats. Twenty-seven days later, ligatures were removed and microbiological samples were obtained directly from the ligatures as well as from the periodontal pockets using absorbent paper points. Microbial analysis was performed using DNA probes to a panel of 40 periodontal species in the checkerboard assay. The bacterial composition patterns were similar for both sampling methods. However, detection levels for all species were markedly higher for ligatures compared with paper points. Ligature samples provided more bacterial counts than paper points, suggesting that the technique for induction of periodontitis could also be applied for sampling in rats. Our findings may be helpful in designing studies of induced periodontal disease-associated microbiota.

Extracorporeal shockwave: mechanisms of action and physiological aspects for cellulite, body shaping, and localized fat-Systematic review.

Extracorporeal Shockwave Therapy (ESWT) has had a wide use in rehabilitation, and has presented positive effects in the treatment of unaesthetic affections. The objective of the present study was to search, in the literature, the mechanisms of action and the physiological aspects of shockwaves acting on the biological tissue to improve the condition of cellulite and localized fat. The systematic review of the literature was carried out in the period of September 2016 to February 2017 based on the bibliographic databases such as Lilacs, Medline, PubMed, and SciELO. Fifteen articles were identified in that systematic review, three of which were excluded as they did not make the complete access to the article available or the theme investigated did not encompass the objective of the study. The revision demonstrated that extracorporeal shockwaves present relevant effects on the biological tissue, which leads to the restructuring of skin properties and subcutaneous tissue, thus clinically improving the aspects of cellulite and localized fat.

Clinical Comparison of Two Photosensitizers for Oral Cavity Decontamination.

OBJECTIVE: In this study, we aim to compare the photodynamic inactivation (PDI) effects of two different photosensitizers (PS), Photogem® and Natural Curcumin, irradiated with light-emitted diodes (LED) at 630 and 450 nm, respectively. BACKGROUND: The current antimicrobial mouthwash for oral hygiene has several drawbacks. In this context, PDI is an alternative technique to inactivate pathogenic microbes in mucosa and in periodontal tissue. Furthermore, there are numerous infectious diseases that may affect the oral cavity, motivating the use of PDI in dentistry. METHODS: The volunteers (n = 50) were randomize separated into five experimental groups (n = 5) for each PS: water control, PS control, light control, and two PS concentrations (25 and 100 mg/L). Each patient underwent mouthwash solution containing the PS before illumination procedure that was performed with an LED device. For microbial decontamination evaluation, the saliva was collected three times: before (T0), immediately after (T1), and 24 h after the illumination procedure (T2). After that, the difference between the colony forming units (CFU) for each volunteer was compared. RESULTS: The results show that regardless of PS and treatment applied, there was microbial reduction immediately after PDI, however, after 24 h only Natural Curcumin still presents a reduction. For Photogem after 24 h, the microorganism returns to the original CFU. CONCLUSIONS: Immediately after PDI, both PS have the same efficiency, nevertheless the Natural Curcumin still has an efficacy after 24 h and also is a more viable photosensitizer. In addition, the results indicate that PDI can be a promised technique used for microbial reducing for the oral cavity.

Comparative clinical study of light analgesic effect on temporomandibular disorder (TMD) using red and infrared led therapy.

Low-level laser therapy (LLLT) has been widely applied in pain relief in several clinical situations, including temporomandibular disorders (TMD). However, the effects of LED therapy on TMD has not been investigated. This study aims to evaluate the effects of red and infrared LEDs on: (1) tissue temperature in ex vivo and (2) pain relief and mandibular range of motion in patients with TMD. Thirty patients between 18 and 40 years old were included and randomly assigned to three groups. The two experimental groups were: the red LED (630 ± 10 nm) group and the infrared LED (850 ± 10 nm) group. The irradiation parameters were 150 mW, 300 mW/cm(2), 18 J/cm(2), and 9 J/point. The positive control group received an infrared laser (780 nm) with 70 mW, 1.7 W/cm(2), 105 J/cm(2), and 4.2 J/point. LED and laser therapies were applied bilaterally to the face for 60 s/point. Five points were irradiated: three points around the temporomandibular joint (TMJ), one point for the temporalis, and one near the masseter. Eight sessions of phototherapy were performed, twice a week for 4 weeks. Pain induced by palpating the masseter muscle and mandibular range of motion (maximum oral aperture) were measured at baseline, immediately after treatment, 7 days after treatment, and 30 days after treatment. There was an increase in tissue temperature during both the red and the infrared LED irradiation in ex vivo. There was a significant reduction of pain and increase of the maximum oral aperture for all groups (p ≥ 0.05). There was no significant difference in pain scores and maximum oral aperture between groups at baseline or any periods after treatment (p ≥ 0.05). The current study showed that red and infrared LED therapy can be useful in improving outcomes related to pain relief and orofacial function for TMD patients. We conclude that LED devices constitute an attractive alternative for LLLT.

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.

Necrosis response to photodynamic therapy using light pulses in the femtosecond regime.

One of the clinical limitations of the photodynamic therapy (PDT) is the reduced light penetration into biological tissues. Pulsed lasers may present advantages concerning photodynamic response when compared to continuous wave (CW) lasers operating under the same average power conditions. The aim of this study was to investigate PDT-induced response when using femtosecond laser (FSL) and a first-generation photosensitizer (Photogem) to evaluate the induced depth of necrosis. The in vitro photodegradation of the sensitizer was monitored during illumination either with CW or an FSL as an indirect measurement of the PDT response. Healthy liver of Wistar rats was used to evaluate the tissue response. The photosensitizer was endovenously injected and 30 min after, an energy dose of 150 J cm(-2) was delivered to the liver surface. We observed that the photodegradation rate evaluated via fluorescence spectroscopy was higher for the FSL illumination. The FSL-PDT produced a necrosis nearly twice as deep when compared to the CW-PDT. An increase of the tissue temperature during the application was measured and was not higher than 2.5 °C for the CW laser and not higher than 4.5 °C for the pulsed laser. FSL should be considered as an alternative in PDT applications for improving the results in the treatment of bulky tumors where higher light penetration is required.

Non-homogeneous liver distribution of photosensitizer and its consequence for photodynamic therapy outcome.

BACKGROUND: Photodynamic therapy is mainly used for treatment of malignant lesions, and is based on selective location of a photosensitizer in the tumor tissue, followed by light at wavelengths matching the photosensitizer absorption spectrum. In molecular oxygen presence, reactive oxygen species are generated, inducing cells to die. One of the limitations of photodynamic therapy is the variability of photosensitizer concentration observed in systemically photosensitized tissues, mainly due to differences of the tissue architecture, cell lines, and pharmacokinetics. This study aim was to demonstrate the spatial distribution of a hematoporphyrin derivative, Photogem, in the healthy liver tissue of Wistar rats via fluorescence spectroscopy, and to understand its implications on photodynamic response. METHODS: Fifteen male Wistar rats were intravenously photosensitized with 1.5mg/kg body weight of Photogem. Laser-induced fluorescence spectroscopy at 532 nm-excitation was performed on ex vivo liver slices. The influence of photosensitizer surface distribution detected by fluorescence and the induced depth of necrosis were investigated in five animals. RESULTS: Photosensitizer distribution on rat liver showed to be greatly non-homogeneous. This may affect photodynamic therapy response as shown in the results of depth of necrosis. CONCLUSIONS: As a consequence of these results, this study suggests that photosensitizer surface spatial distribution should be taken into account in photodynamic therapy dosimetry, as this will help to better predict clinical results.