Exposing human skin to ultraviolet radiation causes DNA damage, sunburn, immune alterations, and eventually, skin cancer. We wished to determine whether liposomes containing a DNA repair enzyme could prevent any of the acute effects of irradiation when applied after ultraviolet exposure. Fifteen human patients with a prior history of skin cancer were exposed to two minimal erythema doses of ultraviolet radiation on their buttock skin. Liposomes containing T4 endonuclease V or heat-inactivated enzyme were applied immediately and at 2, 4, and 5 h after ultraviolet irradiation. Transmission electron microscopy after anti-T4 endonuclease V-staining and immunogold labeling on biopsies taken at 6 h after ultraviolet exposure revealed that the enzyme was present within cells in the skin. Immunohistochemical DNA damage studies suggested a trend toward improved DNA repair at the active T4 endonuclease V liposome-treated test sites. Although the active T4 endonuclease V liposomes did not significantly affect the ultraviolet-induced erythema response and microscopic sunburn cell formation, they nearly completely prevented ultraviolet-induced upregulation of interleukin-10 and tumor necrosis factor-alpha RNA message and of interleukin-10 protein. These studies demonstrate that liposomes can be used for topical intracellular delivery of small proteins to human skin and suggest that liposomes containing DNA repair enzymes may provide a new avenue for photoprotection against some forms of ultraviolet-induced skin damage.

Background: Growth differentiation factor 15 (GDF-15) can serve as a biomarker for cardiovascular disease burden and risk. We evaluated a new, fully automated electrochemiluminescence immunoassay for measuring GDF-15. Methods: Six laboratories independently characterized the Elecsys ® GDF-15 assay (Roche Diagnostics) under routine conditions. Within-run precision (repeatability), within-laboratory precision (intermediate precision), and betweenlaboratory precision (reproducibility) were assessed. Plasma-serum sample correlation, reagent lot-to-lot reproducibility, and instrument comparisons were performed. The Elecsys assay was compared to a research immunoradiometric assay (IRMA) and a commercially available ELISA. GDF-15 concentrations were measured with the Elecsys assay in 739 apparently healthy individuals. Results: CVs for within-run and within-laboratory precision ranged from 0.7% to 7.7% and 1.7% to 8.6%, respectively, for samples containing 670-16 039 ng/L. CVs for between-laboratory precision ranged from 7.1% to 8.9% (766-14 289 ng/L). Recovery of GDF-15 was comparable for serum, Li-heparin plasma, K 2-and K 3-EDTA plasma, and citrated plasma, between 2 reagent lots, and on the cobas e 411 and cobas e 601 analyzers (Roche Diagnostics). GDF-15 concentrations in the clinically relevant range (400-3000 ng/L) measured with the Elecsys assay showed a good correlation and agreement with those measured by IRMA or ELISA. GDF-15 concentrations in apparently healthy individuals increased with age but did not vary by sex. Conclusions: The Elecsys GDF-15 assay demonstrates a robust analytic performance under routine conditions and provides an automated method for measuring GDF-15 concentrations in serum and plasma. IMPACT STATEMENT Growth differentiation factor 15 (GDF-15) is a biomarker of acute and chronic cellular stress that may inform therapeutic decision-making in patients with cardiovascular disease. In the present study, 6 laboratories evaluated a new, fully automated electrochemiluminescence immunoassay for GDF-15. The Elecsys ® GDF-15 assay performed with high within-run, within-laboratory, and between-laboratory precision. The recovery of GDF-15 was comparable with different sample matrices, reagent lots, and laboratory analyzers. GDF-15 concentrations measured with the Elecsys assay showed a good correlation and agreement with 2 previously described manual GDF-15 assays. This study demonstrates a robust analytical performance of the first automated GDF-15 assay under routine conditions.

A 34-year-old woman who was 20 weeks pregnant developed pyoderma gangrenosum while receiving treatment for infarct pneumonia. Because of her septic condition an abortion was performed. The patient received intravenous prednisolone as a pulse treatment for her pyoderma gangrenosum, which was followed by oral methylprednisolone and oral dapsone for 6 weeks. After dose reduction the patient had a severe relapse. The steroid dose was increased and dapsone was replaced by cyclosporin A. The smaller ulcers healed spontaneously, but skin grafting had to be performed for the large ulcer. The steroid therapy was tapered and discontinued. Cyclosporin A was continued for 10 weeks as monotherapy. Subsequently, the patient was free of symptoms for 7 months. Twelve months after the diagnosis of pyoderma gangrenosum the patient developed acute myeloid leukaemia accompanied by a recurrence of the skin disease.

Production rates of dihydrotestosterone (DHT) were determined in healthy men (n = 8), in healthy women during the follicular phase of their menstrual cycle (n = 7), and in young men with male pattern baldness (n = 8) using the stable isotope dilution technique and mass spectrometry. [2,3,4-(13)C]DHT was infused for 10 h at doses of 15 microg/h (men) and 2 microg/h (women), and blood samples were obtained at 20-min intervals during the last 4 h of the observation period. Production rates estimated between April and June were 2.9 +/- 1.1 microg/h (women) and 17.8 +/- 6.2 microg/h (men). In men production rates of DHT were similar (16.2 +/- 7.7 microg/h) when the investigation was repeated between October and December. Mean production rates of DHT in young men with male pattern baldness (60 +/- 50 microg/h) were higher than those in healthy men (P < 0.005). Although this group included two individuals with normal production rates of DHT, the production rate of DHT was markedly elevated (range, 32.0-161.0 microg/h) in the remaining patients. Stable isotope-labeled infusions of DHT are suitable for clinical use in a routine setting to obtain analytically correct estimates of DHT production in vivo. In the majority of men with male pattern baldness endogenous production of DHT is markedly increased, providing a rationale for therapeutic 5 alpha-reductase inhibition in this disorder.

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