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Notizen: Background  Apart from sunscreen lotions, clothing provides protection from acute and chronic sun damage. Therefore, it is very important to know the ultraviolet (UV) protection factor (UPF) of textiles, in particular of lightweight summer clothing. Usually, the UPF of a textile is determined by spectrophotometric assessment of the UV transmission (in vitro method). Objectives  To compare the relationship between in vitro tests and in vivo tests of UPF using solar simulators for determination of the minimal erythema dose (MED), applied to 30 different summer textiles. Methods  Thirty summer textiles were spectrophotometrically assessed, and UPFs were calculated with respect to the International Commission on Illumination (CIE) erythemal action spectrum.1 Based on the in vitro UPFs ‘on skin’ and ‘off skin’, in vivo testing was performed using a solar simulator for the determination of the MEDunprotected and MEDprotected. Results  The UPFs obtained from in vivo‘on skin’ testing were significantly (r = 0·95; P 〈 0·001) lower than the predicted in vitro UPFs. This disparity was also confirmed by chromometric assessment of the MED testing; the erythemal responses measured after textile protection were significantly (P 〈 0·001) higher than those obtained without protection. However, the in vivo‘off skin’ UPFs did not significantly (r = 0·98; P 〉 0·05) differ from the in vitro UPFs; comparison of the chromometrically assessed erythemal responses was also insignificant (P 〉 0·05). Conclusions  The different correlation between in vitro and in vivo measurements of the UPF may be due to the optical–geometrical properties of textiles and the different amount of direct and diffuse radiation passing through the spaces between the yarns. As spectrophotometric measurements of a textile may generally yield lower UPFs than those obtained under average field conditions, the in vitro test method provides ‘safe’ UPF values representing a ‘worst-case scenario’. In contrast to in vitro testing, in vivo methods are much more expensive and time-consuming. Thus, with respect to practicality, spectrophotometric measurements seem to be most suitable for the evaluation of UV protection of textiles.

Notizen: Objective The decreased number of lymphocytes combined with the induction of apoptosis and necrosis seems to be the key mechanism of many phototherapeutic agents. The purpose of our study was to determine the regulating pathway, time course and dose dependence of UVA1- vs. UVB-induced cell death in human T lymphocytes.Methods In our study we applied an in vitro method using single-laser flow cytometry differentiating between intact (Annexin V–FITC−/PI−), apoptotic (Annexin V–FITC+/PI−) and necrotic T cells (Annexin V–FITC+/PI+) following UVA1 (340–400 nm) or UVB (280–320 nm) irradiation. Additionally, fluorescence microscopy of apoptotic cells was performed using acridine orange and ethidium bromide.Results Compared to DNA-binding fluorescent microscopy, the flow cytometric method revealed similar, but more precise, results concerning apoptosis and necrosis. Our data indicate that UVB irradiation exerts its effects by the induction of delayed apoptosis within 24–48 h. In contrast, UVA1 irradiation acts via the dose-dependent induction of immediate apoptosis and necrosis within 6 h.Conclusions Our findings demonstrate that UVA1 irradiation may effect structural and functional modifications leading to immediate initiation of apoptosis followed by early membrane rupture, whereas UVB irradiation leads to DNA damage followed by delayed apoptosis, obviously without initial membrane alteration.

Notizen: Summary Background  Previous studies have indicated that solar and artificial ultraviolet (UV) radiation have a positive influence on psychological variables such as mood and emotional state. Circulating opioid peptides have been suggested as being important in this effect. Objectives  To investigate in a controlled trial the influence of UVA radiation on opioid peptide levels. Methods  We determined plasma levels of β-endorphin immunoreactive material (IRM) and met-enkephalin in UV-exposed ( n  = 35) and non-exposed ( n  = 9) healthy volunteers. On the first day of the study, blood samples were taken from the volunteers (time A). UVA irradiation was subsequently administered with an air-conditioned tanning device. During the UV exposures the volunteers wore opaque goggles. Twenty minutes after UV exposure, blood samples were collected again (time B). Within the following 3 weeks the volunteers had a series of five UV exposures. On the last day of the study (24 h after the sixth UV exposure) blood samples were collected (time C). The cumulative UVA doses were 96 J cm −2 for skin type II and 126 J cm −2 for skin type III. The controls had no UV exposures. Plasma β-endorphin IRM and met-enkephalin levels were determined using radioimmunoassays. Results  At all times of blood collection (A, B, C), there were no significant differences in plasma levels of β-endorphin IRM and met-enkephalin between UV-exposed and non-exposed volunteers ( P  〉 0·05). Conclusions  UVA irradiation does not significantly elevate plasma levels of β-endorphin IRM and met-enkephalin. Therefore we suggest that psychological benefits claimed to occur after UV exposure are unlikely to be mediated by the types of circulating opioid peptides measured in this study.

Notizen: Background/aims: Spectrophotometric assessment (in vitro) is the most established method for determining the ultraviolet protection factor (UPF) of textiles. Apart from stringent requirements for measurement precision, practical methods are required for the routine determination of the UPF. We report here spectrophotometric measurements of textiles using a newly developed autosampler. Measurement precision was evaluated under repeatable conditions.Methods: Fifteen different textiles were spectrophotometrically assessed for the determination of the UPF. Sample handling inside the spectrophotometer was performed with a computer-controlled sampling device, capable of loading and unloading a textile sample from a magazine as well as rotating the sample perpendicular to the spectrometer beam. In order to evaluate the repeatability of measurements, one sample of each textile was assessed eight times under the same conditions in the same laboratory.Results: A mean percentage of the standard error of 1% [EUPF] was calculated for the UPF measurements. For UPFs 〉30, a significantly higher EUPF was found (r=0.78; P〈0.001). EUV (3.9%) of ultraviolet A (UVA) transmission differed significantly from EUV (1.1%) of ultraviolet B (UVB) transmission (P〈0.05).Conclusions: Though a slight decrease of repeatability was observed for UVA transmission measurements and UPFs higher than 30, our data indicate a high measurement precision under repeatable conditions. In conclusion, spectrophotometric measurements of textiles with the aid of the autosampler presented have been shown to be highly practical, time saving and precise.