Multicenter methodology comparison of the FDA and ISO standard for measurement of in vitro UVA protection of sunscreen products.

In vitro standard methods are available and accepted worldwide to assess UVA protection of sunscreen products. Though, harmonisation of methods has made progress in the last decade, still two differing methods - one by FDA the other by ISO - are in use. In a multicentre study including 9 centres in Germany, 4 different commercial sunscreen products were assessed using both methods to discover their similarities and differences. UVA protection factor and Critical Wavelength were detected at various substrate type (sandblasted versus moulded PMMA plates), at different surface roughness of the plates as well as at different product application dose using two different irradiation spectra. Results: The strongest influence on UVA protection factor results from the surface roughness of the plates. Depending on the roughness (accepted range of 2 to 7 µm in the FDA method) a variability in the UVA protection factor of up to 25% was observed, while the much narrower definition of plate roughness by ISO (4.5 to 5.2 µm) had no relevant influence on the test results. Sandblasted plates in our assessment led to higher UVA protection factors and produced less scattered results compared to moulded plates. These differences were not pronounced. Application dose and spectra of the irradiation source were of negligible influence on UVA protection factor results for the investigated UV-filter combinations. The UVA protection factor which is the endpoint of the ISO method was found to be a parameter with a high potential to differentiate among different test products. The endpoint of the FDA method - the Critical Wavelength - was found to be an unambitious endpoint. Insensitivity to all described modifications of the method was observed. All investigated products performed similar and passed the Critical Wavelength criteria independent of method and parameters.

Undescended testis? How best to teach the physical examination.

BACKGROUND: Undescended testis in boys is common. Guidelines recommend surgical treatment between the ages of 6 months and 2 years; nevertheless, orchidopexy is frequently performed at later ages. One reason is the belated diagnosis due to a perceived difficulty in the physical examination (PE) and correct localization of the testis. OBJECTIVES: We aimed to find an effective method for teaching the physical examination of the testis in a child. STUDY DESIGN: An interdisciplinary team developed teaching sessions, including an educational video and a simulator. Medical students (n = 133) were randomized into three groups: self-study only, video, and video and simulator. The sessions were carried out and quantitative feedback was collected from the teachers and students. The learning achievements of the different groups were assessed with an objective structured clinical examination (OSCE). The differences in mean OSCE results between all three groups were tested using one-way analysis of variance (ANOVA). For multiple pairwise comparisons, a closed testing procedure was performed using unpaired t-tests. RESULTS: The self-study only group acquired the poorest results in the OSCE, with a mean score of 5.1 out of 10. The video-only-group reached a mean of 6.7, and the video-and-simulator group performed best with a mean score of 8.5. The differences between all three groups were found to be statistically significant, with P = 0.007. The attached figure illustrates this data. If analyzed in pairs, this difference was particularly apparent between the groups self-study only vs video and simulator, with P = 0.002. Qualitative feedback revealed doubtful effectiveness for educational videos, but positive reactions to training on a simulator. DISCUSSION: The poor results of the self-study-only group were in accordance with the literature, where textbook learning was found not to increase OSCE results. The effectiveness of video tutorials remains doubtful; studies focusing on this teaching method are divergent and the present students' feedback supports this data. The effective teaching with the simulator has been proven for other skills (i.e. ultrasound skills). The analyzed cohort for this study was small, and the study should be repeated at different institutions and with larger numbers of students to assure generalizability. CONCLUSIONS: Low-fidelity pediatric simulators with palpable testis are available and are able to improve examining skills in medical students. We hope the presented study inspires medical educators in their teaching of the PE of the pediatric testis.