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The JOS Young Investigators Awards 2014
orthodontic waves 74 (2015) 91–92
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.elsevier.com/locate/odw
The JOS Young Investigators Awards 2014 Liquid diet induces memory impairment accompanied by a decreased number of hippocampal neurons in mice Hidemasa Okihara1,2, Jinichi Ito2, Satoshi Kokai1, Takayoshi Ishida1, Maya Hiranuma1, Chiho Kato1, Tadachika Yabushita1, Kazuto Ishida3, Takashi Ono1, Makoto Michikawa2 1
Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, Japan 2 Biomedical Science, Graduate School of Medical Sciences, Nagoya City University, Japan 3 Department of Physical Therapy, Graduate School of Medicine, Nagoya University, Japan The masticatory dysfunction affects not only the peripheral nervous system, but also the central nervous system that is involved in memory and learning ability. Previous studies have shown that the masticatory dysfunction is significantly associated with dementia and Alzheimer’s disease. As the related substance in memory and learning ability, BDNF, one of the neurotrophin families is important. The regulation of synaptic plasticity related to memory and learning ability is the primary function of BDNF and TrkB. Moreover we examined the ratio of phospho-p44/42 ERK/pan ERK, a downstream molecule of BDNF/TrkB signaling. In this study, we examined the effects of mastication on memory, we performed the behavioral experiment, the quantitative evaluation of these protein levels by Western blotting, and the number of neurons in the hippocampus of mice. C57 BL/6J male mice (3 weeks old) were randomly divided into the control group (n = 7) and the experimental group (n = 7) soon after being weaned. From 3 weeks to 14 weeks, the control group was fed chow pellets, while the experimental group was fed a liquid diet. At 14 weeks, we performed passive avoidance test. After the behavioral experiment, extirpated brain was separated into cerebral cortex and hippocampus. In the behavioral experiment, the time until entering the dark box on the second day in the experiment group was significantly shorter than that in the control group. In hippocampus of the experimental group, the protein level of BDNF significantly increased and that of TrkB and phospho-p44/42 ERK significantly decreased compared with the control group. In cerebral cortex, there were no differences in these protein levels between the two groups. The numbers of pyramidal neurons in the hippocampus CA1 and CA3 regions of experimental group were significantly lower than those of control group. The masticatory dysfunction in early childhood may induce the impairment of memory and learning ability. (J Neurosci Res 2014;92:1010-7) PMID: 24687840 http://dx.doi.org/10.1002/jnr.23383
The orthopaedic effects of bone-anchored maxillary protraction in a beagle model Yosuke Ito1, Tatsuo Kawamoto
1,2
, Keiji Moriyama1
1 Section of Maxillofacial Orthognathics, Department of Maxillofacial Reconstruction and Function, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Japan 2 Division of Orofacial Functions and Orthodontics, Kyushu Dental College, Japan.
There are some clinical reports on bone-anchored maxillary protraction (BAMP) using class III elastics between miniplates implanted for skeletal anchorage in the upper and lower jaws. However, there is currently no basic information on the biology of http://dx.doi.org/10.1016/j.odw.2015.10.001 1344-0241/
92
orthodontic waves 74 (2015) 91–92
this treatment modality. Hence, the aim of this study was to establish an animal model of BAMP using beagles and to verify the effects of such treatment in this model. Ten immature (90-day-old) male beagles were used. One miniplate per jaw quadrant was placed and secured with screws. From days 0 to 60, miniplates in the dogs in the intermaxillary traction group (Group T, n = 5) were loaded with coil springs. In the control group (Group C, n = 5), the miniplates underwent no force application. Every 20 days from day 20, all dogs were assessed by acquiring standardized lateral cephalometric radiographs. Cephalometric analyses were performed, and the two groups were compared using linear and angular analyses. New bone formation was labeled by doublefluorochrome administration with calcein and tetracycline. The animals were sacrificed on day 60, and bone sections of the zygomaticomaxillary sutures were analyzed using histomorphometry with fluorescence microscopy. The two groups were compared with the Mann–Whitney U-test (P < 0.05). Cephalometric analysis indicated significant maxillary advancement and retroclination of the maxillary incisors in Group T, with concomitant significant posterior relocation of the condyles and proclination of the mandibular incisors. In histomorphometric analysis, the BV/TV in Group T was significantly smaller than that in Group C (P < 0.01), and the MAR and BFR/BS in Group T were significantly larger than those in Group C (P < 0.01). Vigorous bone apposition at the zygomaticomaxillary suture was only detected in Group T. Our results using this newly developed animal model support the application of BAMP for clinical orthopedic treatment. (Eur J Orthod 2014; 36:632-40) PMID: 24265464 http://dx.doi.org/10.1093/ejo/cjt083
Microsatellite genome-wide association study for mandibular prognathism Keiichiro Ikuno 1, Takashi S Kajii2, Akira Oka3, Hidetoshi Inoko4, Hiroyuki Ishikawa2, Junichiro Iida1 1
Department of Orthodontics, Division of Oral Functional Science, Graduate School of Dental Medicine, Hokkaido University, Japan Section of Orthodontics, Department of Oral Growth and Development, Fukuoka Dental College, Japan 3 The Institute of Medical Science, Tokai University, Japan 4 Department of Molecular Life Sciences, Division of Basic Medical Science and Molecular Medicine, Tokai University School of Medicine, Japan 2
Attempts have been made to identify susceptibility genes of mandibular prognathism by genome-wide linkage studies, but the results of susceptibility loci are inconsistent. There has been no genome-wide association study (GWAS) of mandibular prognathism. The objective of this study was to perform a GWAS using 23465 microsatellite markers to detect mandibular prognathism susceptibility regions. The study was based on the pooled DNA method, including two steps of screening on the whole genome and subsequent individual genotyping, with 240 cases and 360 controls in the Japanese population. Two suggestive associations on chromosomes 1q32.2 (D1S1358i: P = 4.22E-04) and 1p22.3 (D1S0411i: P = 6.66E-04) were shown, and PLXNA2 and SSX2IP were suggested to be candidate genes. 1p22.3 flanked the region indicated by previous linkage analysis. The results of the GWAS show that two loci (1q32.2 and 1p22.3) are likely to be susceptibility regions of mandibular prognathism. 1p32.2 is a novel locus, and identification of 1p22.3 supports the results of previous linkage analysis. (Am J Orthod Dentofacial Orthop 2014;145:757-62) PMID: 24880846 http://dx.doi.org/10.1016/j.ajodo.2014.01.022
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.elsevier.com/locate/odw
The JOS Young Investigators Awards 2014 Liquid diet induces memory impairment accompanied by a decreased number of hippocampal neurons in mice Hidemasa Okihara1,2, Jinichi Ito2, Satoshi Kokai1, Takayoshi Ishida1, Maya Hiranuma1, Chiho Kato1, Tadachika Yabushita1, Kazuto Ishida3, Takashi Ono1, Makoto Michikawa2 1
Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, Japan 2 Biomedical Science, Graduate School of Medical Sciences, Nagoya City University, Japan 3 Department of Physical Therapy, Graduate School of Medicine, Nagoya University, Japan The masticatory dysfunction affects not only the peripheral nervous system, but also the central nervous system that is involved in memory and learning ability. Previous studies have shown that the masticatory dysfunction is significantly associated with dementia and Alzheimer’s disease. As the related substance in memory and learning ability, BDNF, one of the neurotrophin families is important. The regulation of synaptic plasticity related to memory and learning ability is the primary function of BDNF and TrkB. Moreover we examined the ratio of phospho-p44/42 ERK/pan ERK, a downstream molecule of BDNF/TrkB signaling. In this study, we examined the effects of mastication on memory, we performed the behavioral experiment, the quantitative evaluation of these protein levels by Western blotting, and the number of neurons in the hippocampus of mice. C57 BL/6J male mice (3 weeks old) were randomly divided into the control group (n = 7) and the experimental group (n = 7) soon after being weaned. From 3 weeks to 14 weeks, the control group was fed chow pellets, while the experimental group was fed a liquid diet. At 14 weeks, we performed passive avoidance test. After the behavioral experiment, extirpated brain was separated into cerebral cortex and hippocampus. In the behavioral experiment, the time until entering the dark box on the second day in the experiment group was significantly shorter than that in the control group. In hippocampus of the experimental group, the protein level of BDNF significantly increased and that of TrkB and phospho-p44/42 ERK significantly decreased compared with the control group. In cerebral cortex, there were no differences in these protein levels between the two groups. The numbers of pyramidal neurons in the hippocampus CA1 and CA3 regions of experimental group were significantly lower than those of control group. The masticatory dysfunction in early childhood may induce the impairment of memory and learning ability. (J Neurosci Res 2014;92:1010-7) PMID: 24687840 http://dx.doi.org/10.1002/jnr.23383
The orthopaedic effects of bone-anchored maxillary protraction in a beagle model Yosuke Ito1, Tatsuo Kawamoto
1,2
, Keiji Moriyama1
1 Section of Maxillofacial Orthognathics, Department of Maxillofacial Reconstruction and Function, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Japan 2 Division of Orofacial Functions and Orthodontics, Kyushu Dental College, Japan.
There are some clinical reports on bone-anchored maxillary protraction (BAMP) using class III elastics between miniplates implanted for skeletal anchorage in the upper and lower jaws. However, there is currently no basic information on the biology of http://dx.doi.org/10.1016/j.odw.2015.10.001 1344-0241/
92
orthodontic waves 74 (2015) 91–92
this treatment modality. Hence, the aim of this study was to establish an animal model of BAMP using beagles and to verify the effects of such treatment in this model. Ten immature (90-day-old) male beagles were used. One miniplate per jaw quadrant was placed and secured with screws. From days 0 to 60, miniplates in the dogs in the intermaxillary traction group (Group T, n = 5) were loaded with coil springs. In the control group (Group C, n = 5), the miniplates underwent no force application. Every 20 days from day 20, all dogs were assessed by acquiring standardized lateral cephalometric radiographs. Cephalometric analyses were performed, and the two groups were compared using linear and angular analyses. New bone formation was labeled by doublefluorochrome administration with calcein and tetracycline. The animals were sacrificed on day 60, and bone sections of the zygomaticomaxillary sutures were analyzed using histomorphometry with fluorescence microscopy. The two groups were compared with the Mann–Whitney U-test (P < 0.05). Cephalometric analysis indicated significant maxillary advancement and retroclination of the maxillary incisors in Group T, with concomitant significant posterior relocation of the condyles and proclination of the mandibular incisors. In histomorphometric analysis, the BV/TV in Group T was significantly smaller than that in Group C (P < 0.01), and the MAR and BFR/BS in Group T were significantly larger than those in Group C (P < 0.01). Vigorous bone apposition at the zygomaticomaxillary suture was only detected in Group T. Our results using this newly developed animal model support the application of BAMP for clinical orthopedic treatment. (Eur J Orthod 2014; 36:632-40) PMID: 24265464 http://dx.doi.org/10.1093/ejo/cjt083
Microsatellite genome-wide association study for mandibular prognathism Keiichiro Ikuno 1, Takashi S Kajii2, Akira Oka3, Hidetoshi Inoko4, Hiroyuki Ishikawa2, Junichiro Iida1 1
Department of Orthodontics, Division of Oral Functional Science, Graduate School of Dental Medicine, Hokkaido University, Japan Section of Orthodontics, Department of Oral Growth and Development, Fukuoka Dental College, Japan 3 The Institute of Medical Science, Tokai University, Japan 4 Department of Molecular Life Sciences, Division of Basic Medical Science and Molecular Medicine, Tokai University School of Medicine, Japan 2
Attempts have been made to identify susceptibility genes of mandibular prognathism by genome-wide linkage studies, but the results of susceptibility loci are inconsistent. There has been no genome-wide association study (GWAS) of mandibular prognathism. The objective of this study was to perform a GWAS using 23465 microsatellite markers to detect mandibular prognathism susceptibility regions. The study was based on the pooled DNA method, including two steps of screening on the whole genome and subsequent individual genotyping, with 240 cases and 360 controls in the Japanese population. Two suggestive associations on chromosomes 1q32.2 (D1S1358i: P = 4.22E-04) and 1p22.3 (D1S0411i: P = 6.66E-04) were shown, and PLXNA2 and SSX2IP were suggested to be candidate genes. 1p22.3 flanked the region indicated by previous linkage analysis. The results of the GWAS show that two loci (1q32.2 and 1p22.3) are likely to be susceptibility regions of mandibular prognathism. 1p32.2 is a novel locus, and identification of 1p22.3 supports the results of previous linkage analysis. (Am J Orthod Dentofacial Orthop 2014;145:757-62) PMID: 24880846 http://dx.doi.org/10.1016/j.ajodo.2014.01.022