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In order to establish a consensus recommendation for performing photopatch testing, a photopatch test taskforce group was established under the joint umbrella of the European Society for Contact Dermatitis and the European Society for Photodermatology in 2000. After proposing the most adequate methodology in 2004 and completing a European multicentre photopatch test study in 2011, this taskforce is recommending a list of photoallergens that should form part of a baseline series for photopatch testing in Europe. It contains mainly ultraviolet filters and drugs, mostly non-steroidal anti-inflammatory drugs. The choice of chemicals was based on the results of a recent multicentre study, previous published cases of photoallergy, and use of the substances in the European market. It is suggested that an extended list of photoallergens should be photopatch tested in selected cases, along with patients' own products. Two contact allergens, cinnamyl alcohol and decyl glucoside, should be simultaneously patch tested in order to clarify photopatch and patch test reactions, respectively, to ketoprofen and methylene bis-benzotriazolyl tetramethylbutylphenol (Tinosorb M™). [ABSTRACT FROM AUTHOR]

Eukaryotic protein-coding genes are transcribed as pre-mRNAs that are matured by capping, splicing and cleavage and polyadenylation. Although human pre-mRNAs can be long and complex, containing multiple introns and many alternative processing sites, they are usually processed co-transcriptionally. Mistakes during nuclear mRNA maturation could lead to potentially harmful transcripts that are important to eliminate. However, the processes of human pre-mRNA degradation are not well characterised in the human nucleus. We have studied how aberrantly processed pre-mRNAs are degraded and find a role for the 5??3? exonuclease, Xrn2. Xrn2 associates with and co-transcriptionally degrades nascent ?-globin transcripts, mutated to inhibit splicing or 3? end processing. Importantly, we provide evidence that many endogenous pre-mRNAs are also co-transcriptionally degraded by Xrn2 when their processing is inhibited by Spliceostatin A. Our data therefore establish a previously unknown function for Xrn2 and an important further aspect of pre-mRNA metabolism that occurs co-transcriptionally. [ABSTRACT FROM AUTHOR]

Summary Background/Purpose Low vitamin D levels have been associated with adverse effects on health. The primary source of vitamin D is cutaneous production during sunlight exposure. Sun avoidance can restrict vitamin D photosynthesis and is common practice amongst patients with photosensitivity. Few studies have examined vitamin D status in this population, particularly those in northern latitudes. The purpose of this study was therefore to investigate the prevalence and possible predictors of low vitamin D status in patients referred to a tertiary photodiagnostic service. Methods A case note review of 165 patients who attended the National Photodiagnostic Service for assessment at the Photobiology Unit in Dundee, Scotland (latitude 56° N) over 1 year was conducted. Clinical information and serum 25-hydroxyvitamin D (25( OH) D) concentration were documented. Multivariate analyses were used to identify predictors of vitamin D status. Results Mean 25( OH) D concentration was 41.9 nmol/ L [standard deviation ( SD) 22.0]. Forty percent of patients had insufficient vitamin D levels [25( OH) D 25-49 nmol/ L] and 25% were vitamin D deficient [25( OH) D < 25 nmol/ L]. Blood collection in winter was the strongest predictor of low 25( OH) D status ( P < 0.001); strict photoprotection ( P = 0.04), onset of symptoms within an hour of sunlight exposure ( P = 0.01) and abnormal monochromator phototesting responses ( P = 0.009) also predicted low vitamin D levels. Supplement use was associated with higher vitamin D levels ( P < 0.001), even amongst patients who strictly avoided sunlight ( P = 0.03). Conclusions Patients with photosensitivity who live in northern latitudes are at high risk of low vitamin D levels, particularly in winter and spring. Increased awareness of this risk is crucial to ensure preventative strategies, such as supplementation, are implemented. [ABSTRACT FROM AUTHOR]

Background: Photoallergic contact dermatitis (PACD) presents in patients after certain exogenous agents come into contact with the skin in the presence of ultraviolet and/or visible light. The best method currently available for investigating PACD is photopatch testing. However, photopatch testing as an investigation is under-used by clinicians, and therefore PACD may go undetected in many patients. Purpose: To highlight the importance of PACD and photopatch testing when investigating patients with a photo-exposed site dermatosis. Method: A comprehensive review of the available literature relating to PACD and photopatch testing. Results: Experimental evidence suggests that PACD is a delayed type hypersensitivity reaction. Various agents have been historically shown to cause PACD, but currently the most common photosensitizers are sunscreens and topical non-steroidal anti-inflammatory drugs. Photopatch testing has in the past been subject to differing methodologies; however, a European consensus methodology now exists and should allow a greater comparison of results across centres. As chemical, pharmaceutical, and cosmetic industries produce new agents, photopatch testing of such agents in humans before release in the marketplace may prevent widespread contact with potent photosensitizers. It will also be important for ongoing multi-centre studies of existing agents to be conducted in order to keep the photopatch test batteries used by clinicians investigating PACD up to date. [ABSTRACT FROM AUTHOR]

RNA interference (RNAi) is widespread in eukaryotes and regulates gene expression transcriptionally or post-transcriptionally. In fission yeast, RNAi is tightly coupled to template transcription and chromatin modifications that establish heterochromatin in cis. Exogenous double-stranded RNA (dsRNA) triggers seem to induce heterochromatin formation in trans only when certain silencing proteins are overexpressed. Here, we show that green fluorescent protein (GFP) hairpin dsRNA allows production of high levels of Argonaute-associated small interfering RNAs (siRNAs), which can induce heterochromatin formation at a remote locus. This silencing does not require any manipulation apart from hairpin expression. In cells expressing a ura4+–GFP fusion gene, production of GFP siRNAs causes the appearance of ura4 siRNAs from the target gene. Production of these secondary siRNAs depends on RNA-dependent RNA polymerase Rdp1 (RDRPRdp1) function and other RNAi pathway components. This demonstrates that transitivity occurs in fission yeast and implies that RDRPRdp1 can synthesize RNA from targeted RNA templates in vivo, generating siRNAs not homologous to the hairpin. [ABSTRACT FROM AUTHOR]

Background: The maximum concentration of organic sunscreen filters in current usage that does not lead to irritant reactions when performing photopatch testing is not known. Such irritant reactions can be misinterpreted as positive photoallergic contact dermatitis reactions. Objective: To determine the frequency of irritant reactions to 19 organic sunscreen filters in current use. Patients/Methods: Ninety-four healthy volunteers were photopatch tested using the European consensus methodology to three different concentrations (2%, 5%, and 10%) of 19 organic sunscreen filters at the Photobiology Unit in Dundee, UK. Results: Of the 94 subjects recruited, 80 were analysed after withdrawals and exclusions. Of the 19 organic sunscreen filters studied, only 2 compounds led to irritant reactions in ≥5% subjects. Five per cent and 10% benzophenone-4 led to irritant reactions in four and six subjects, respectively. Five per cent methylene bis-benzotriazolyl tetramethylbutylphenol led to irritant reactions in six subjects, but unlike benzophenone-4, this was not in a dose-dependent fashion. Conclusions: When performing photopatch testing according to the European consensus methodology with these 19 organic sunscreen filters, a 10% concentration is suitable for all filters, except benzophenone-4, which should be tested at a concentration of 2%. [ABSTRACT FROM AUTHOR]

Background: Neuriplege® cream was available as a non-prescription medication in France until its withdrawal from the market by regulatory authorities in January 2007. Its active ingredient is the phenothiazine chlorproethazine (CPE). Before its withdrawal, we investigated the photocontact allergic and phototoxic potential of Neuriplege® cream and CPE. Methods: An in vitro phototoxic study was performed in HaCaT keratinocytes using the neutral red dye phototoxic assay. Phototoxicity and photocontact allergy were assessed in humans by photopatch testing. Results: In vitro, a 1 h incubation of keratinocytes with CPE was approximately 13 times as toxic to the cells in the presence of ultraviolet light compared with incubation with the drug alone. Of two healthy volunteers initially photopatch tested to Neuriplege® cream on the arm, one developed a phototoxic reaction. These two volunteers were then photopatch tested to Neuriplege® and CPE on the back with seven additional healthy volunteers. Both of the initial study volunteers experienced a photocontact allergic reaction to Neuriplege® as is upon this re-exposure. Of the seven volunteers not previously exposed to Neuriplege® as is, five developed phototoxic reactions. Conclusions: This study demonstrates the strong phototoxic and photocontact allergic potential of CPE in Neuriplege® cream, and supports the decision of the French pharmaceutical regulatory authorities to withdraw it. [ABSTRACT FROM AUTHOR]

Topical photodynamic therapy (PDT) causes localized phototoxicity and has been shown both in vitro and in humans to have immunomodulatory and immunosuppressive effects. We report a case of localized bullous pemphigoid (BP) developing after PDT. Although BP has been reported to develop following cutaneous insults such as surgery, radiotherapy, psoralen ultraviolet A (PUVA) and ultraviolet B phototherapy, PDT has not previously been reported as a trigger. Possible mechanisms include direct mechanical injury to the basement membrane and subsequent autoantibody formation, an indirect immunomodulatory effect of PDT, or most likely, precipitation of BP in individuals with pre-existing low titres of epidermal autoantibodies (so-called subclinical BP). PDT should be added to the list of possible exogenous triggers for BP and this condition should be considered if blistering develops following PDT. [ABSTRACT FROM AUTHOR]

The article presents a study which examined the divergence of the related species Mycoplasma genitalium and Mycoplasma pneumoniae, focusing on silent sites within genes and factors that may influence their G+C content. An investigation of a variation in G+C content is provided. Identification of 456 pairs of homologous genes from the two species is presented.

The article presents a case study of a 25-year-old female with erythematous papulo-vesicular rash on sun-exposed sites. She underwent photopatch testing using ultraviolet (UV) A with 19 organic UV filters and five topical non-steroidal anti-inflammatory drugs (NSAIDs). Meanwhile, monochromator phototesting was performed on three 10 x 10 cm areas at her back skin. Results showed an increase in photoallergic contact dermatitis (PACD) responses.

Drug-induced phototoxicity can be caused by topical or systemic agents and is diagnosed on the basis of clinical history, examination and appropriate investigations. Photopatch testing is the investigation of choice for topical photocontact allergic dermatitis, but its use in drug-induced phototoxicity has not been validated. We retrospectively analyzed the results of photopatch testing to the drug quinine sulfate in three patients in whom a diagnosis of drug-induced phototoxicity to this agent had been made. None of the three patients had positive photopatch test reactions at any time point. This demonstrates that in our patients, photopatch testing to quinine sulfate was not a useful additional investigation for diagnosing drug-induced phototoxicity. [ABSTRACT FROM AUTHOR]