Der Gastrointestinaltrakt als Eintrittspforte für fremde Makromoleküle: DNA und Proteine

Das Plasmid pEGFP-C1 wird an Mäuse oral verabreicht. Die fremde, mit der Nahrung aufgenommene DNA kann sowohl im Inhalt des Gastrointestinaltraktes, als auch in den Zellen der Darmwand und in verschiedenen Organen mit Hilfe gentechnischer Methoden nachgewiesen werden. Weiterhin wird gezeigt, dass durch eine Komplexierung der DNA an ein Protein eine Protektion der Nukleinsäuren durch die Detektierung geringer DNA-Mengen nachgewiesen werden kann. Auch fremde, mit der Nahrung aufgenommene Proteine können in den Organen persistieren. Dies wird am Beispiel der Glutathion S Transferase gezeigt

Deficiency of the clock gene Bmal1 affects neural progenitor cell migration

We demonstrate the impact of a disrupted molecular clock in Bmal1-deficient (Bmal1−/−) mice on migration of neural progenitor cells (NPCs). Proliferation of NPCs in rostral migratory stream (RMS) was reduced in Bmal1−/− mice, consistent with our earlier studies on adult neurogenesis in hippocampus. However, a significantly higher number of NPCs from Bmal1−/− mice reached the olfactory bulb as compared to wild-type littermates (Bmal1+/+ mice), indicating a higher migration velocity in Bmal1−/− mice. In isolated NPCs from Bmal1−/− mice, not only migration velocity and expression pattern of genes involved in detoxification of reactive oxygen species were affected, but also RNA oxidation of catalase was increased and catalase protein levels were decreased. Bmal1+/+ migration phenotype could be restored by treatment with catalase, while treatment of NPCs from Bmal1+/+ mice with hydrogen peroxide mimicked Bmal1−/− migration phenotype. Thus, we conclude that Bmal1 deficiency affects NPC migration as a consequence of dysregulated detoxification of reactive oxygen species

Accuracy of Two Variants of 3D-Printed Insertion Guides for Orthodontic Mini-Implants: An Ex Vivo Study in Human Cadavers

Insertion guides are becoming popular for orthodontic mini-implant positioning. The aim of this study was to evaluate and compare the accuracy of two different mini-implant insertion guides, with or without pre-drilling, in a human cadaveric model. Maxillary casts of six fresh frozen specimens were digitized to create insertion guides. Sixty mini-implants were randomly inserted with full-arch or skeletonized guides, either with or without predrilling. Pre- and post-treatment CBCTs were superimposed using rigid registration. Transformation matrices of the planned and real positions were obtained, and distances at the mini-implant neck and apex, as well as the angular deviation, were calculated. The Kruskal–Wallis test was performed, followed by a post hoc test when indicated. Out of 60 inserted mini-implants, 46 could be evaluated. Of these, 10 initially assigned to no pre-drilling required this procedure due to very high bone density. Therefore, 32 implants were inserted with pre-drilling (n = 15 full-arch; n = 17 skeletonized) and 14 without (n = 7 full-arch; n = 7 skeletonized). The lowest mean deviation at the neck was 1.22 ± 0.6 mm, registered in the full-arch/pre-drilling group. The skeletonized/no pre-drilling group presented the lowest mean values at the apex, i.e., 1.72 ± 1.22 mm, as well as the lowest mean angular deviation, i.e., 8.23 ± 4.24°. Significant differences among groups were observed only at the neck, with higher mean deviation in the skeletonized/pre-drilling group than in the full-arch/pre-drilling one (p = 0.014). In conclusion, within the limitations of the study, rather high deviations between planned and real mini-implant positions were found. Further studies are needed on how to improve the accuracy within in vivo settings