Layer Thickness of SPF 30 Sunscreen and Formation of Pre-vitamin D.

Background: Most studies have demonstrated that sunscreens with lower sun protection factor (SPF) do not prevent the production of vitamin D because much lower amount of sunscreen (SPF<30) is applied than recommended (2 mg/cm(2)) indicating that a significant amount of UV radiation can penetrate the skin. Since less sunscreen is applied, higher SPF sunscreens may be used to achieve the desired protection. However, there is little information regarding the application of high-SPF sunscreen and vitamin D formation.

Clearance mechanism of protoporphyrin IX from mouse skin after application of 5-aminolevulinic acid.

Background: 5-Aminolevulinic acid (ALA) or its esters mediated photodynamic therapy (PDT) is the most widely practiced form of PDT in dermatology. One of its advantages is that undesirable photosensitization lasts only for 24-48 h. In order to optimize ALA-PDT it is necessary to understand the mechanisms of intracellular production and clearance of PpIX (efflux from cells into blood stream and/or its conversion into haem).

The action spectrum for folic acid photodegradation in aqueous solutions.

Folate is essential for cell division and growth. Deficiency is linked to birth defects, magaloblastic anaemia, cardiovascular disease, etc. Folic acid is a synthetic form of folate and is used to fortify food and in supplements.

Effect of vitamin D supplementation and ultraviolet B exposure on serum 25-hydroxyvitamin D concentrations in healthy volunteers: a randomized, crossover clinical trial.

Background: Solar ultraviolet (UV) radiation during the summer and vitamin D supplementation are two major sources of vitamin D for humans at northern latitudes. However, little is known about the relative efficiency of these two vitamin D sources.

Objectives: The main goal was to compare the efficiency of high-dose oral vitamin D3 supplementation (2000 IU per day for 30 days) with a simulated summer UV exposure [10 sunbed sessions to a total dose of 23·8 standard erythema doses (SED)] to improve vitamin D status.

Fluorescence photobleaching of ALA and ALA-heptyl ester induced protoporphyrin IX during photodynamic therapy of normal hairless mouse skin: a comparison of two light sources and different illumination schemes.

This study investigated photobleaching of protoporphyrin IX (PpIX) induced by 5-aminolevulinic acid (ALA) and ALA-heptyl ester during superficial photodynamic therapy (PDT) in normal skin of the female BALB/c-nu/nu athymic mouse. We examined the effects of two light sources (laser and broadband lamp) and two different illumination schemes (fractionated light and continuous irradiation) on the kinetics of photobleaching. Our results show that light exposure (0-30 minutes, 10 mW/cm2) of wavelengths of approximately 420 nm (blue light) and 635 nm (red light) induced time-dependent PpIX photobleaching for mouse skin of 2% ALA and ALA-heptyl ester.