Novel non-calcemic secosteroids that are produced by human epidermal keratinocytes protect against solar radiation.

CYP11A1 hydroxylates the side chain of vitamin D3 (D3) in a sequential fashion [D3→20S(OH)D3→20,23(OH)2D3→17,20,23(OH)3D3], in an alternative to the classical pathway of activation [D3→25(OH)D3→1,25(OH)2D3]. The products/intermediates of the pathway can be further modified by the action of CYP27B1. The CYP11A1-derived products are biologically active with functions determined by the lineage of the target cells.

Photobiological safety evaluation of UV nail lamps.

We evaluated six UV nail lamps representative of major US manufacturers to evaluate radiant hazards as defined in ANSI/IESNA RP-27 Recommended Practice for Photobiological Safety. Lamps were evaluated at three positions, 1 cm above the inner surface approximating exposure to the hand and the 20 cm RP-27 non-general light source distance, oriented normal and 45° to the opening. Hazard to skin at intended use distance classified these devices into Risk Group 1 or 2 (Low to Moderate) with S(λ) weighted Actinic UV ranging 1.

FDA-sunlamp recommended Maximum Timer Interval And Exposure Schedule: consensus ISO/CIE dose equivalence.

The authors compared calculations of sunlamp maximum exposure times following current USFDA Guidance Policy on the Maximum Timer Interval and Exposure Schedule, with USFDA/CDRH proposals revising these to equivalent erythemal exposures of ISO/CIE Standard Erythema Dose (SED). In 2003, [USFDA/CDRH proposed replacing their unique CDRH/Lytle] erythema action spectrum with the ISO/CIE erythema action spectrum and revising the sunlamp maximum exposure timer to 600 J m(-2) ISO/CIE effective dose, presented as being biologically equivalent. Preliminary analysis failed to confirm said equivalence, indicating instead ∼38% increased exposure when applying these proposed revisions.

Cutaneous hypothalamic-pituitary-adrenal axis homolog: regulation by ultraviolet radiation.

The hypothalamic-pituitary-adrenal (HPA) axis maintains basal and stress-related homeostasis in vertebrates. Skin expresses all elements of the HPA axis including corticotropin-releasing hormone (CRH), proopiomelanocortin (POMC), ACTH, β-endorphin (β-END) with corresponding receptors, the glucocorticoidogenic pathway, and the glucocorticoid receptor (GR). To test the hypothesis that cutaneous responses to environmental stressors follow the organizational structure of the central response to stress, the activity of the "cutaneous HPA" axis homolog was investigated after exposure to ultraviolet radiation (UVR) wavelengths of UVA (320-400 nm), UVB (280-320 nm), and UVC (100-280 nm) in human skin organ culture and in co-cultured keratinocytes/melanocytes.

Comparative effectiveness of clinically used light sources for cutaneous protoporphyrin IX-based photodynamic therapy.

This report documents the optical characteristics of a number of photodynamic therapy (PDT) light sources of varied types, measured and indexed relative to estimated effectiveness for activation of the PDT chromaphore protoporphyrin IX (PpIX). PDT sources in use at several clinics, including intense pulsed light (IPL) sources, lasers, and continuous wave (CW) light sources, were spectroradiometrically measured and indexed relative to their overlap to an absorption spectrum of PpIX. The sources were highly disparate, varying in power from irradiance in the mW/cm(2) range for the CW sources up to ∼30 J/cm(2) per flash for the IPL sources.

Holick's rule and vitamin D from sunlight.

Holick's rule says that sun exposure 1/4 of a minimal erythemal dose (MED) over 1/4 of a body is equivalent to 1000 International Units (IU) oral vitamin D3. Webb and Engelsen recently commented that the ultraviolet (UV) spectrum used to establish Holick's rule is unknown. They consequently used a spring midday Boston solar spectrum to estimate ample sunlight exposures for previtamin D3 (preD3) at various locations.

Variability of pre-vitamin D3 effectiveness of UV appliances for skin tanning.

While there is limited documentation that certain indoor tanning lamps effectively produce vitamin D, the diversity of such devices has not been extensively surveyed. This study compares the spectral effectiveness of a variety of tanning units, and solar spectra, for ultraviolet (UV) photosynthesis of pre-vitamin D3 (preD3) and UV induced erythema. Well-established techniques exist for the calculation of spectral effectiveness for photobiological responses that have defined action spectra.

The FDA proposed solar simulator versus sunlight.

The US Food and Drug Administration is in the process of formulating final rules for sunscreen labeling and testing. They have adopted a version of the solar simulator standard proposed by COLIPA, a European cosmetic products trade association. From our files we have selected spectral data on several solar simulators that comply with the proposed rules and have compared these sources both one to another and to several standard solar spectra of Air Mass 1.

Examination of solar simulators used for the determination of sunscreen UVA efficacy.

The U.S. FDA recently proposed both in vivo and in vitro UVA efficacy tests for sunscreen products with the lower result used to establish the sunscreen's labeled UVA protection claim.

Indoor tanning injuries: an evaluation of FDA adverse event reporting data.

Background/aims: In 1979 the Food and Drug Administration (FDA) designated indoor tanning units would be regulated medical devices and that each must have an exposure timer. In 1985 FDA added a scheduled series of doses designed to allow tanning with little risk of concomitant sunburn. Subsequently FDA/CDRH maintained databases in which medical device associated injuries were reported.

In vitro sunscreen transmittance measurement with concomitant evaluation of photostability: evolution of a method.

The recent paper by Miura et al. (Photochem. Photobiol.

Analysis of compact fluorescent lights for use by patients with photosensitive conditions.

Ultraviolet radiation (UVR) is hazardous to patients with photosensitive skin disorders, such as lupus erythematosus, xeroderma pigmentosum and skin cancer. As such, these patients are advised to minimize their exposure to UVR. Classically, this is accomplished through careful avoidance of sun exposure and artificial tanning booths.

The risk of ultraviolet radiation exposure from indoor lamps in lupus erythematosus.

It is well known that ultraviolet radiation can exacerbate skin disease in patients with lupus erythematosus. While many patients are advised to avoid sunlight and artificial tanning, it is not clear how best to counsel patients regarding the use of indoor lamps. Indeed, many of the light bulbs commonly used in the home and workplace emit low-dose ultraviolet radiation.

Commentary on 'UVB-SPF': the SPF labels of sunscreen products convey more than just UVB protection.

The FDA recently published a proposed amendment of the Final Monograph for OTC Sunscreen Products. Among the proposals, FDA revised solar simulator performance specifications and additional labeling for sunscreen products. The maximum allowable labeled sun protection factor (SPF) was increased to SPF 50 while simultaneously requiring it to be called 'UVB-SPF'.

25-Hydroxyvitamin D, cholesterol, and ultraviolet irradiation.

Vitamin D deficiency may have implications for cardiovascular health. The purpose of this study was to determine the relationship of 25-hydroxyvitamin D (25[OH]D) to cholesterol and lipoprotein particles and to determine whether increasing 25(OH)D through ultraviolet (UV) irradiation impacted on these parameters in healthy young men and women. This was a randomized trial of 51 adults exposed to suberythemal doses of whole-body irradiation using UV lamps that emitted UV-A and UV-B radiation, compared with a control group, twice weekly for 12 weeks.

The increase in melanoma: are dietary furocoumarins responsible?

According to most cancer registries the incidence of cutaneous melanoma (CM) has been increasing for several decades. Unlike other skin cancers, CM does not clearly correlate with exposure to ultraviolet radiation. The strongest etiological evidence for CM in man is genetic predisposition, evidenced by very high risks in primary relatives of melanoma patients, and photochemotherapy with 8-methoxy psoralen in combination with ultraviolet-A radiation (PUVA) to treat psoriasis and vitiligo.

A practical UV source to induce Herpes simplex labialis lesions in the clinic.

Background: Ultraviolet (UV) sources have been used to clinically induce herpes simplex lesions in the lips of susceptible individuals.

Methods: This study reports the optimization of a UV source for studies involving multiple clinical laboratory sites and subsequent clinical UV induction of cold sore lesions. We describe novel adaptations of a commercially available broadband UV phototherapy lamp that facilitate determination of individual's minimal erythemal dose (MED) and expose the lips with minimal risk of viral transmission to or between the volunteers and technicians.

Darkness at noon: sunscreens and vitamin D3.

We are assured by responsible scientific and governmental organizations that sunscreens should be routinely worn to reduce skin cancer risk. We are also advised that wearing sunscreens will not hinder our ability to produce sufficient previtamin D3 (preD3) from casual sunlight exposure. We report the examination of a series of 166 solar spectra, obtained on different days throughout a year, evaluated for erythemic and preD3 effectiveness and the relative effects of recommended Sun protection factor (SPF) 15 sunscreen.

Sunscreen ingredients inhibit inducible nitric oxide synthase (iNOS): a possible biochemical explanation for the sunscreen melanoma controversy.

Sunscreen products are rated upon their ability to inhibit visible redness of the skin 24 h after measured doses of ultraviolet (UV) exposure (Sun Protection Factor, SPF). Although sunscreens prevent UV-induced redness, their ability to protect against melanoma or the development of moles is less clear. UV-induced redness occurs in part by the action of nitric oxide (NO), synthesized in the skin.

Unexpected photolysis of the sunscreen octinoxate in the presence of the sunscreen avobenzone.

A major concern raised about photostability studies of sunscreen products is that the photodegradation of sunscreens does not readily translate into changes in product performance. This study examines the correlation between photochemical degradation of sunscreen agents and changes in protection provided by sunscreen films. Films of a commercial sunscreen product containing avobenzone, oxybenzone and octinoxate were irradiated using a fluorescent UV-A phototherapy lamp with additional UV-B blocking filter.

Modest in vivo exposure to solar wavelengths induces a visible absorbing chromophore in Skh-1 mouse epidermis.

Background/purpose: In the previous work, we correlated epidermal hyperplasia with increased epidermal absorption in the 250-400 nm region. During a recent review of that work, the apparent formation of a chromophore, with absorption slightly longer than 400 nm, in the epidermis of irradiated animals was noted. In this study, we have extended the transmission measurement to include the 250-800 nm region.