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Rev1 has two important functions in the translesion synthesis pathway, including dCMP transferase activity, and acts as a scaffolding protein for other polymerases involved in translesion synthesis. However, the role of Rev1 in mutagenesis and tumorigenesis in vivo remains unclear. We previously generated Rev1‐overexpressing (Rev1‐Tg) mice and reported that they exhibited a significantly increased incidence of intestinal adenoma and thymic lymphoma (TL) after N‐methyl‐N‐nitrosourea (MNU) treatment. In this study, we investigated mutagenesis of MNU‐induced TL tumorigenesis in wild‐type (WT) and Rev1‐Tg mice using diverse approaches, including whole‐exome sequencing (WES). In Rev1‐Tg TLs, the mutation frequency was higher than that in WT TL in most cases. However, no difference in the number of nonsynonymous mutations in the Catalogue of Somatic Mutations in Cancer (COSMIC) genes was observed, and mutations involved in Notch1 and MAPK signaling were similarly detected in both TLs. Mutational signature analysis of WT and Rev1‐Tg TLs revealed cosine similarity with COSMIC mutational SBS5 (aging‐related) and SBS11 (alkylation‐related). Interestingly, the total number of mutations, but not the genotypes of WT and Rev1‐Tg, was positively correlated with the relative contribution of SBS5 in individual TLs, suggesting that genetic instability could be accelerated in Rev1‐Tg TLs. Finally, we demonstrated that preleukemic cells could be detected earlier in Rev1‐Tg mice than in WT mice, following MNU treatment. In conclusion, Rev1 overexpression accelerates mutagenesis and increases the incidence of MNU‐induced TL by shortening the latency period, which may be associated with more frequent DNA damage‐induced genetic instability. [ABSTRACT FROM AUTHOR]

Background: The relationship between the maximum lip‐closing force (LCF) and malocclusion has long been studied. Recently, a method to measure the ability to control directional LCF from eight directions (upper, lower, right, left and the four directions in between) during lip pursing was established. Objective: It is considered important to evaluate the ability to control directional LCF. The aim of this study was to investigate the ability of skeletal class III patients to control directional LCF. Methods: Fifteen skeletal class III patients (mandibular prognathism group) and 15 people with normal occlusion (normal occlusion group) were recruited. The maximum LCF and the accuracy rate (the ratio of the matched time in which the participant was able to keep the LCF in the target range over a total time of 6 s) were measured. Results: The maximum LCF was not significantly different between the mandibular prognathism group and the normal occlusion group. The accuracy rate in the mandibular prognathism group was significantly lower in all six directions than that in the individual normal occlusion group. Conclusion: As the accuracy rate in all six directions was significantly lower in the mandibular prognathism group than that in the normal occlusion group, occlusion and craniofacial morphology might influence lip function. [ABSTRACT FROM AUTHOR]

Chlorogenic acid (CGA) is a polyphenol that is present in coffee beans, many vegetables, and fruits. Since CGA has been reported to exert antioxidant and anti-inflammatory effects, it is expected to protect against periodontitis. In the present study, we used a ligature-induced experimental periodontitis model and investigated the beneficial effects of CGA against alveolar bone resorption caused by experimental periodontitis. To examine the inhibitory effects of CGA on bone loss, a ligature was wrapped around the maxillary right second molar, and CGA was intraperitoneally injected once a day for 2 weeks. In another experiment to investigate the restorative effects of CGA on bone loss, a ligature was wrapped around the maxillary right second molar for 2 weeks, it was then removed, and CGA was intraperitoneally injected once a day for 2 weeks. At the end of the experiments, the maxillae were removed, and CT images were taken. Alveolar bone loss was measured as the distance from the cement–enamel junction to the alveolar crest. The statistical analysis was performed using GraphPad Prism6 (Dunn's multiple comparison test). The results revealed that the ratio of the buccal alveolar bone loss (vs. the bone loss on the nonligated side) induced by ligation was significantly decreased by the administration of CGA (5 mg/kg) for 2 weeks. Moreover, the bone loss ratio on the buccal and palatal sides after 2 weeks of ligation was significantly decreased by the 2-week administration of CGA (5 mg/kg). The present results revealed that CGA exerted preventive effects against alveolar bone loss caused by experimental periodontitis. [ABSTRACT FROM AUTHOR]

Am J Physiol Regul Integr Comp Physiol 298: R34-R42, 2010. First published October 21, 2009; doi: 10.1152/ajpregu.00205.2009.--Exaggerated jaw motor activities during sleep are associated with muscle symptoms in the jaw-closing rather than the jaw-opening muscles. The intrinsic activity of antagonistic jaw muscles during sleep remains unknown. This study aims to assess the balance of muscle activity between masseter (MA) and digastric (DG) muscles during sleep in guinea pigs. Electroencephalogram (EEG), electroocculogram, and electromyograms (EMGs) of dorsal neck, MA, and DG muscles were recorded with video during sleep-wake cycles. These variables were quantified for each 10-s epoch. The magnitude of muscle activity during sleep in relation to mean EMG activity of total wakefulness was up to three times higher for MA muscle than for DG muscle for nonrapid eye movement (NREM) and rapid-eye-movement (REM) sleep. Although the activity level of the two jaw muscles fluctuated during sleep, the ratio of activity level for each epoch was not proportional. Epochs with a high activity level for each muscle were associated with a decrease in [delta]EEG power and/or an increase in heart rate in NREM sleep. However, this association with heart rate and activity levels was not observed in REM sleep. These results suggest that in guinea pigs, the magnitude of muscle activity for antagonistic jaw muscles is heterogeneously modulated during sleep, characterized by a high activity level in the jaw-closing muscle. Fluctuations in the activity are influenced by transient arousal levels in NREM sleep but, in REM sleep, the distinct controls may contribute to the fluctuation. The above intrinsic characteristics could underlie the exaggeration of jaw motor activities during sleep (e.g., sleep bruxism). masseter; digastric; EEG; heart rate

Long-period fiber Bragg gratings fabricated by exposure of hydrogen-loaded fiber to UV laser light exhibit large-scale dynamic evolution for approximately two weeks at room temperature. During this time two distinct features show up in their spectrum: a large upswing in wavelength and a substantial deepening of the transmission minimum. The dynamic evolution of the transmission spectrum is explained quantitatively by use of Malo's theory of UV-induced quenching [Electron. Lett. 30, 442 (1994)] followed by refilling of hydrogen in the fiber core and the theory of hydrogen diffusion in the fiber material. The amount of hydrogen quenched by the UV irradiation is 6% of the loaded hydrogen. OCIS codes: 050.2770, 060.2310, 060.2340, 160.5340.