Electron paramagnetic resonance imaging using nitroxides is a powerful method for visualizing the redox status modulated by oxidative stress in vivo. Typically, however, data acquisition times have been too slow to obtain a sufficient number of projections for three-dimensional images, when using continuous wave-electron paramagnetic resonance imager in small rodents, using nitroxides with comparatively short T 2 and a half-life values. Because of improvements in imagers that enable rapid data-acquisition, the feasibility of three-dimensional electron paramagnetic resonance imaging with good quality in mice was tested with nitroxides. Three-dimensional images of mice were obtained at an interval of 15 sec under field scanning of 0.3 sec and with 46 projections in the case of strong electron paramagnetic resonance signals. Threedimensional electron paramagnetic resonance images of a blood brain barrier-permeable nitroxide, 3-hydroxymethyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl, in the mouse head clearly showed that 3-hydroxymethyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl was distributed within brain tissues, and this was confirmed by MRI observations. Based on the pharmacokinetics of nitroxides in mice, half-life mapping was demonstrated in an ischemia-reperfusion model mouse brain. Inhomogeneous half-lives were clearly mapped pixel-by-pixel in mouse head under oxidative stress by the improved continuous wave-electron paramagnetic resonance imager noninvasively. Magn Reson Med 65:295-303,

No abstract

This review paper discusses the relationship between the mastication and learning and memory in rats. Immunohistochemistry of choline acetyltransferase (ChAT) showed that the numbers of ChAT-positive neurons in the nucleus of the diagonal band/medial septal nucleus (NDB/MS) of a powder diet group (PDG) and a molar crown-less powder diet group (MCPDG) were smaller than those of solid diet group (SDG). Subsequently, the concentrations of acetylcholine (ACh) in the hippocampus and in the cerebral cortex in MCPDG were significantly lower than that of SDG. The response latency of the MCPDG group was significantly shorter in passive avoidance tests. The impact of mastication on recovery of learning and memory function rats receiving permanent middle cerebral artery occlusion (MCAO) was also evaluated. In a Morris water maze task, rats fed a solid diet after MCAO surgery had greater functional recovery than rats fed a liquid. Finally, a whole-cell patch-clamp study revealed crucial roles of nitric oxide (NO) in the physiological control of cholinergic neurons in NDB/MS and in the pathogenic mechanism for cell death. Collectively, these results suggest key roles for NO both in the learning and memory function, and potentially in dementia. Mastication may have a significant impact on the maintenance and recovery of learning and memory, presumably through pathogenic and physiological mechanisms of NO action. #

Objectives The aim of this study was to investigate whether the newly developed artificial dental plaque (A‐DP) is useful as an educational tool for denture care of dental hygienist that compared it with conventional artificial dental plaque from the viewpoint of practical skills. Material and methods The 125 dental hygienist school students and 26 dental hygienists who had clinical experience were subjected a practical training of denture plaque control using the conventional denture plaque (C‐DP) and the A‐DP. The questionnaires based on the semantic differential method were used to survey whether the A‐DP is similar to the real denture plaque (R‐DP). Factor analysis by rotation of promax was carried out. Results In the results of the factor analysis, the two factors could be detected in students and three factors in dental hygienists. The total score of each denture plaque was calculated for each factor, and correlation coefficient was examined. There was significant correlation between the A‐DP and the R‐DP at the first factors, both students and dental hygienists. C‐DP was not similar to R‐DP in all factors. Conclusions These results suggested that A‐DP resembles R‐DP better than C‐DP. It was concluded that the A‐DP was similar to the R‐DP and could be a potent educational tool for practical denture care.

No abstract

Purpose: Although a relationship between masticatory function and higher brain function has been reported, its mechanism has not been revealed. Higher brain function, which includes the development of neural circuits and their functional expression after the differentiation and maturation of neurons, the ramification of dendrites and the formation of synapses, involves the synthesis of cholesterol by brain-derived neurotrophic factor. In this study, we evaluated whether solid feed, which requires mastication, is more conducive than liquid feed to the expression of brain-derived neurotrophic factor and its synthesis of cholesterol in rats.Methods: After rats were raised on solid or liquid feed for eight weeks, the brain tissue was divided into the cerebellum, medulla oblongata, hypothalamus, mesencephalon -hippocampus -corpus striatum, and cerebral cortex. The expression of brain-derived neurotrophic factor was measured by real-time RT-PCR, the receptors for brain-derived neurotrophic factor were immunostained and the total amount of cholesterol was measured.Results: Rats raised on solid feed had significantly greater expression of brain-derived neurotrophic factor and more receptors for it as well as a greater total amount of cholesterol in cerebral cortex. Conclusions:This study suggests that mastication affects the synthesis of cholesterol via brain-derived neurotrophic factor involved in learning and memory function.

No abstract

No abstract