Photodynamic Therapy Interventions in Facial Photodamage: A Systematic Review.

INTRODUCTION: Photodynamic therapy (PDT) involves the combination of a light source and a photosensitizing agent to induce tissue damage via the generation of singlet oxygen. Although topical PDT has been approved for other indications, its use in facial photodamage is uncertain. AIMS: To assess the efficacy and safety of PDT in facial skin photoaging. METHODS: All randomized clinical trials (RCTs) evaluating the efficacy and safety of any form of topical PDT for the treatment of facial photodamage (dermatoheliosis) or photoaging in patients older than 18 years, were included. Photodynamic-therapy using any topical photosensitizing agent at any dose, and with any light-source, were considered. Comparators were chemical exfoliation, intense pulsed light (IPL), light emitting diodes (LED), dermabrasion or microdermabrasion, ablative or non-ablative lasers, injectables, surgery, placebo and/or no treatment. A systematic search in PubMed, Embase, Lilacs, Google Scholar and RCT's registry databases, was performed. RESULTS: Search was conducted up to May 4th 2016. Four authors independently selected and assessed methodological quality of each RCT. According to inclusion criteria, twelve studies were included (6 aminolevulinate (ALA) trials and 6 methyl aminolevulinate (MAL) trials), but the majority of them had methodological constraints particularly in randomization description and patients/outcome assessors blindness. DISCUSSION AND CONCLUSIONS: Overall results indicated that PDT either with ALA or with MAL was effective and safe for facial photodamage treatment, but high quality of evidence was found mainly for MAL studies.

Note: Device for obtaining volumetric, three-component velocity fields inside cylindrical cavities.

We describe a device designed and built to obtain the three-component, steady state velocity field in the whole volume occupied by a fluid in motion contained in a cavity with cylindrical walls. The prototype comprises a two-camera stereoscopic particle image velocimetry system mounted on a platform that rotates around the volume under analysis and a slip ring arrangement that transmits data from the rotating sensors to the data storage elements. Sample observations are presented for natural convection in a cylindrical container but other flows can be analyzed.

Haemorheological variables in a rat model of hypertriglyceridaemic obesity and diabetes.

Obesity is a heterogeneous condition of variable aetiology, generally associated with pathologies such as arterial hypertension, hyperlipidaemia, diabetes and cardiac disease. These conditions, either themselves or because of the various treatments used, may further modify blood rheology in an arbitrary manner. Therefore, analyses of changes in the blood rheology induced by obesity in humans have had differing and controversial results. In our laboratory, a model of hypertriglyceridaemic obesity is provided by an inbred rat strain; the beta genotype from the IIMb/Fm strain, presenting a syndrome of moderate obesity with apparent peripubertal onset, associated with hypertriglyceridaemia and glucose intolerance that turns into diabetes. The alpha genotype, originated from the same IIM/Fm stock, represents the control. The present study describes a comparative analysis of the variables determining the rheological behaviour of the blood in obese and control strains. Our results, agreeing with some other studies performed in humans, confirmed the haemorheological changes associated with obesity, and the fact that these changes became more evident in the presence of pathologies such as diabetes. It appears that triglyceridaemia. cholesterolaemia and hyperglycaemia may influence the rheological behaviour of the cell membrane and this damage may provoke a decrease in erythrocyte deformability and, consequently, hyperviscosity of the blood.

The pH of hydrogen peroxide disinfection systems over time.

We evaluated the pH of four hydrogen peroxide systems over a 28-day period of normal daily use to determine if pH changes occurred which could cause ocular discomfort. Using a Corning Model 10 pH meter, we measured the initial pH of the disinfection and neutralization solutions and the final pH of the neutralization solutions over each system's disinfection and neutralization cycle. The final pH of the four systems did not change significantly over the 28-day period; however, the final pH of two of the hydrogen peroxide systems were consistently closer to the physiological pH of tears than the other two systems evaluated. These findings suggest that initial discomfort experienced over a 28-day period of normal daily use of any of the hydrogen peroxide disinfection systems studied may be due to the individual system used, but not due to pH changes within a system. However, individual sensitivities to pH should be considered.