Mouse Models of Allergic Diseases: TSLP and Its Functional Roles

ABSTRACTThe cytokine TSLP was originally identified in a murine thymic stromal cell line as a lymphoid growth factor. After the discovery of TSLP, extensive molecular genetic analyses and gene targeting experiments have demonstrated that TSLP plays an essential role in allergic diseases. In this review, we discuss the current status of TSLP and its functional role in allergic diseases particularly by focusing on effects of TSLP on haematopoietic cells in mouse models. It is our conclusion that a number of research areas, i.e., a new source of TSLP, effects of TSLP on non-haematopoietic and haematopoietic cells, synergistic interactions of cytokines including IL-25 and IL-33 and a regulation of TSLP expression and its function, are critically needed to understand the whole picture of TSLP involvement in allergic diseases. The mouse models will thus contribute further to our understanding of TSLP involvement in allergic diseases and development of therapeutic measures for human allergic diseases

Biomechanical effects of offset placement of dental implants in the edentulous posterior mandible

Background: Proper implant placement is very important for long-term implant stability. Recently, numerous biomechanical studies have been conducted to clarify the relationship between implant placement and peri-implant stress. The placement of multiple implants in the edentulous posterior mandible has been studied by geometric analysis, three-dimensional finite element analysis (FEA), model experimentation, etc. Offset placement is a technique that reduces peri-implant load. However, few studies have used multiple analyses to clarify the value of the offset placement under identical conditions.The present study aimed to clarify the biomechanical effects of offset placement on the peri-implant bone in edentulous posterior mandibles by comparative investigation using FEA and model experimentation with strain gauges.Methods: Three implants were embedded in an artificial mandible in the parts corresponding to the first premolar, the second premolar, and the first molar. A titanium superstructure was mounted to prepare models (experimental models). Three load points (buccal, central, and lingual) were established on the part of the superstructure corresponding to the first molar. Three types of experimental models, each with a different implant placement, were prepared. In one model, the implants were placed in a straight line; in the other two, the implants in the parts corresponding to the second premolar and the first molar were offset each by a 1-mm increment to the buccal or lingual side. Four strain gauges were applied to the peri-implant bone corresponding to the first molar.The experimental models were imaged by micro-computed tomography (CT), and FEA models were constructed from the CT data. A vertical load of 100 N was applied on the three load points in the experimental models and in the FEA models. The extent of compressed displacement and the strain in the peri-implant bone were compared between the experimental models and the FEA models Results: Both experimental and FEA models suffered the least compressed displacement during central loading in all placements. The greatest stress and compressive strain was on the load side in all types of placements.Conclusions: Offset placement may not necessarily be more biomechanically effective than straight placement in edentulous posterior mandibles.Keywords: Offset placement, Three-dimensional finite element analysis, FEA, Amount of compressed displacement, Stress distribution, Strain gaug

A biomechanical investigation of mandibular molar implants: reproducibility and validity of a finite element analysis model

Background: Three-dimensional finite element analysis (FEA) is effective in analyzing stress distributions around dental implants. However, FEA of living tissue involves many conditions, and the structures and behaviors are complex; thus, it is difficult to ensure the validity of the results. To verify reproducibility and validity, we embedded implants in experimental models and constructed FEA models; implant displacements were compared under various loading conditions. Methods: Implants were embedded in the molar regions of artificial mandibles to fabricate three experimental models. A titanium superstructure was fabricated and three loading points (buccal, central, and lingual) were placed on a first molar. A vertical load of 100 N was applied to each loading point and implant displacements were measured. Next, the experimental models were scanned on micro computed tomography (CT) and three-dimensional FEA software was used to construct two model types. A model where a contact condition was assumed for the implant and artificial mandible (a contact model) was constructed, as was a model where a fixation condition was assumed (a fixation model). The FEA models were analyzed under similar conditions as the experimental models; implant displacements under loading conditions were compared between the experimental and FEA models. Reproducibility of the models was assessed using the coefficient of variation (CV), and validity was assessed using a correlation coefficient.Results: The CV of implant displacement was 5–10% in the experimental and FEA models under loading conditions. Absolute values of implant displacement under loading were smaller in FEA models than the experimental model, but the displacement tendency at each loading site was similar. The correlation coefficient between the experimental and contact models for implant displacement under loading was 0.925 (p < 0.01). The CVs of equivalent stress values in the FEA models were 0.52–45.99%.Conclusions: Three-dimensional FEA models were reflective of experimental model displacements and produced highly valid results. Three-dimensional FEA is effective for investigating the behavioral tendencies of implants under loading conditions. However, the validity of the absolute values was low and the reproducibility of the equivalent stresses was inferior; thus, the results should be interpreted with caution

A new species of Xenoturbella from the western Pacific Ocean and the evolution of Xenoturbella

BackgroundXenoturbella is a group of marine benthic animals lacking an anus and a centralized nervous system. Molecular phylogenetic analyses group the animal together with the Acoelomorpha, forming the Xenacoelomorpha. This group has been suggested to be either a sister group to the Nephrozoa or a deuterostome, and therefore it may provide important insights into origins of bilaterian traits such as an anus, the nephron, feeding larvae and centralized nervous systems. However, only five Xenoturbella species have been reported and the evolutionary history of xenoturbellids and Xenacoelomorpha remains obscure.ResultsHere we describe a new Xenoturbella species from the western Pacific Ocean, and report a new xenoturbellid structure - the frontal pore. Non-destructive microCT was used to investigate the internal morphology of this soft-bodied animal. This revealed the presence of a frontal pore that is continuous with the ventral glandular network and which exhibits similarities with the frontal organ in acoelomorphs.ConclusionsOur results suggest that large size, oval mouth, frontal pore and ventral glandular network may be ancestral features for Xenoturbella. Further studies will clarify the evolutionary relationship of the frontal pore and ventral glandular network of xenoturbellids and the acoelomorph frontal organ. One of the habitats of the newly identified species is easily accessible from a marine station and so this species promises to be valuable for research on bilaterian and deuterostome evolution

Consideration of the Psychosocial Process of Overcoming Crises by Yogo Teachers

This study aimed to elucidate the psychological process of overcoming crises by yogo teachers. On eight yogo teachers of A city who have experienced crises in the past, we conducted semi-structured interviews. As a result of analyzing the content of the interviews, using the modified grounded theory approach; seven categories and eighteen perspectives were extracted. Yogo teachers would fall in crises by feeling [wobble of existence as a yogo teacher], and although they would try to make a [positive backdown] tentatively, they would retain the [uncompromising desires to accomplish their duties]. Then, by getting energy from people around them such as their children or colleagues, they would search for“ cooperators” to [find a clue to solve the problem], and would find “solutions through trial and error” and carry out “strategies of assessment and deliberation”. Eventually, yogo teachers got a“regained confidence”will proceed to [before again]. Those yogo teachers who have gone through crises were [aware of their owng rowths].本研究は、養護教諭が危機を乗り越える心理社会的プロセスを明らかにすることを目的とした。A市内に勤務する、過去に危機を経験した養護教諭8名を対象として、半構造化面接を行った。修正版グラウンデッド・セオリー・アプローチを用いて面接内容を分析した結果、7のカテゴリーと18の概念が抽出された。養護教諭は、【養護教諭としての存在の揺らぎ】を感じ、危機に陥る。そのような状況から、一時的には【前向きな撤退】を図るものの、養護教諭としての職務を遂行しようとする【養護教諭としての譲れない思い】を持ち続けている。そして、子どもや同僚など周囲の人からの【エネルギー補給】しながら、問題の【解決への一手】を図るため、〈協力者の探索〉をし、〈試行錯誤の解決策〉見つけ出し、〈見極めて練る戦略〉を実行していく。やがて、〈取り戻した自信〉を得た養護教諭は、【もう一度、前へ】進んでいく。危機を乗り越えた養護教諭は、自らの【成長の自覚】をしていた