Photodynamic therapy mediated by a red LED and methylene blue inactivates resistant Leishmania amazonensis.

Cutaneous leishmaniasis is a neglected parasitic disease that leads to destructive lesions. The emergence of drug resistance has been a global concern over the past years. Photodynamic therapy (PDT) mediated by a red LED and methylene blue (MB) involves the overproduction of oxidative stress, which oxidizes several cellular biomolecules and prevents the selection of resistant strains. Herein, we investigated the potential of PDT mediated by MB against wild-type and miltefosine-resistant strains of Leishmania amazonensis. As a result, both strains were susceptible to PDT, thus encouraging us to seek the best conditions to overcome the drug resistance problem in cutaneous leishmaniasis.

Evaluation of the Preventive Effect of Photobiomodulation on Orofacial Discomfort in Dental Procedures: A Randomized-Controlled, Crossover Study and Clinical Trial.

Background: Orofacial pain has been a prevalent symptom in the worldwide population, which may cause restrictions in daily activities and, consequently, have a great impact on the well-being of affected individuals. Photobiomodulation using light sources, such as low-level laser or light emitting diodes, with different wavelengths, has been widely used in the last years, in addition to being a noninvasive, low-cost resource and reducing pain. Objective: This study aimed at evaluating the effect of photobiomodulation as a protocol treatment to prevent facial muscle discomfort after long-term clinical procedures. Methods: The volunteers were randomized and allocated as follows: laser (n = 16) and placebo (n = 16) groups, following a crossover study design. The laser parameters were as following: 786 nm wavelength, 9 J per point, and 100 mW power of 2.393 W/cm2 irradiance. The discomfort was induced by simulating a 50-min dental procedure (with bilateral mouth open), and the pain scale (assessed bilaterally), tiredness, and temperature measurement through thermography were used for analysis. Results: The results showed a significant lower pain and tiredness in the laser group. Also, the results showed a statistically significant valid temperature change between the groups at times: T1, T40, and T50. Conclusions: According to our results, photobiomodulation showed a positive effect on the face musculature in patients submitted to the treatments, reducing pain and improving the subjective perception of exertion.

Effects of photobiomodulation on interleukin-10 and nitrites in individuals with relapsing-remitting multiple sclerosis - Randomized clinical trial.

OBJECTIVE: Investigate the effects of photobiomodulation (PBM) on the expression of IL-10 and nitrites in individuals with Relapsing-Remitting multiple sclerosis (MS), as these biomarkers play a fundamental role in the physiopathology of the disease. The modulation of IL-10 and nitrites through treatment with PBM may be a novel treatment modality for MS. METHODS: A randomized, uncontrolled, clinical trial was conducted involving 14 individuals with a diagnosis of Relapsing-Remitting MS and a score of up to 6.0 on the Expanded Disability Status Scale (EDSS). THE PARTICIPANTS WERE RANDOMIZED TO TWO GROUPS: Group 1 -PBM in the sublingual region; Group 2 -PBM over the radial artery. Irradiation was administered with a wavelength of 808 nm and output power of 100 mW for 360 seconds twice a week, totaling 24 sessions. Peripheral blood was analyzed for the determination of serum levels of IL-10 and nitrites. RESULTS: After treatment with PBM, the expression of IL-10 increased in both the sublingual group (pre-treatment: 2.8 ± 1.4 pg/ml; post-treatment: 8.3 ± 2.4 pg/ml) and the radial artery group (pre-treatment: 2.7 pg/ml ± 1.4; post-treatment: 11.7 ± 3.8 pg/ml). In contrast, nitrite levels were not modulated in the sublingual group (pre-treatment: 65 ± 50 nmol/mg protein; post-treatment: 51 ± 42 nmol/mg protein) or the radial artery group (pre-treatment: 51 ± 16 nmol/mg protein; post-treatment: 42 ± 7 nmol/mg protein). CONCLUSION: Treatment with PBM positively modulated the expression of IL-10 but had no effect on nitrite levels. Further studies should be conducted with a larger sample and a control group, as PBM may be a promising complementary treatment for the management of MS. This trial is registered at ClinicalTrials.gov. Identifier: NCT03360487.

Photodynamic antimicrobial chemotherapy action of phenothiazinium dyes in planktonic Candida albicans is increased in sodium dodecyl sulfate.

BACKGROUND: Photodynamic antimicrobial chemotherapy (PACT) is an important therapeutic platform for antimicrobial activity, especially due to the resistant strains, however, the physical-chemical properties of the photosensitizers may affect the final outcome. Recently, this research group showed that the control of aggregation potentiates the PACT action of Methylene Blue. In this study, the researchers investigated the PACT action of other phenothiazinium dyes (PDs), such as Azure A, Azure B (AB), and 1,9-dimethyl methylene blue (DMMB), and the effects of different mediums which modulate PD aggregation were studied. METHODS: The C. albicans planktonic culture was treated with PDs at different concentrations (0-100.00 mg/L), both in the dark (5 min) and irradiated (640 ±â€¯12 nm LED during 30 min, 2.60 mW/cm2). After the treatments, the diluted samples were grown on Sabouraud Dextrose Agar and maintained at 37 °C for 24 h. Later, one single concentration was defined and the inoculum was treated with the compounds in different media (water, phosphate buffer saline - PBS, physiological solution - 0.90 % NaCl, urea 1.00 mol/L, and sodium dodecyl sulfate 0.25 % - SDS), at 20.00 mg/L for AA and AB, and at 0.50 mg/L for DMMB. The cell uptake and the dimer to the monomer ratios were determined by spectrophotometry. RESULTS: PACT with the PDs showed a reduction in the CFU/mL, with DMMB being the most effective due to the higher cell uptake within the series. When PACT was applied in the different mediums, the inactivation response was influenced by the medium. In water, the physiological solution, PBS, and urea showed no significant differences in relation to the control group. On the other hand, SDS potentiated the PACT action, and the inactivation of the microorganism was achieved with AB and DMMB. CONCLUSIONS: In water, DMMB presented the highest PACT action within the PDs being studied, reaching a microorganism inactivation with a 1.00 mg/L solution, mainly due to its high cell uptake. SDS 0.25 % increased the PACT action of the PDs studied, mainly with DMMB and AB, and this may be used in formulations to develop antimicrobial treatments to be used in clinics.