A simplified sieving method for measuring masticatory performance

An objective and simple method for evaluating masticatory function in patients is necessary for diagnosis and outcome assessment in prosthetic treatment. The objective of this study was to simplify Kapur\u27s chewing test using peanuts. A mechanical peanut pulverization procedure was developed simulate a complete denture wearer\u27s chewing performance. Corresponding to the variable B (ml) for the total volume on various sieves used to measure masticatory performance by Kapur\u27s method, a constant K (ml) was used to simplify the method and K was determined in accordance with measurements of mechanical pulverization and the results of chewing tests by 20 complete denture wearers. The constant K was established as 20ml. The correlation between the evaluated masticatory performance by Kapur\u27s method and the method here was 0.998 (p<0.01) by in vitro pulverization and, 0.808 (p<0.01) in 20 complete denture wearers

<ORIGINAL ARTICLE>Histologic investigation of tissue surrounding bone in a HA-coated implant supported super structure with and without stress-absorbing elements

The effectiveness of the implant-supported overdentures has been attracted attention for edentulous patients, and a number of studies have been reported. Implant-supported overdentures refer to implant-retained tissue-borne overdentures and it is different from the implant-supported fixed partial dentures recommended by Branemark. In implant-supported overdentures, the functional load may concentrate on implant where there is rigid connection. Loaded implants may cause a resorption of surrounding bone, leading to malfunction, loosing, and the ultimate failure of the implant. The present study reports a stress-absorbing element using a resilient compound designed as the super structure of a two-piece titanium core with hydroxyapatite coated cylinder implants, to avoid stress concentrations, and a histological comparison of the surrounding bone tissue with rigid elements. No notable histological differences were observed in the trabecular patterns by contact microradiography and light microscopy

The role of AmeloD in tooth development

The development of ectodermal organs, such as teeth, requires epithelial–mesenchymal interactions. Basic helix–loop–helix (bHLH) transcription factors regulate various aspects of tissue development, and we have previously identified a bHLH transcription factor, AmeloD, from a tooth germ cDNA library. Here, we provide both in vitro and in vivo evidence that AmeloD is important in tooth development. We created AmeloD-knockout (KO) mice to identify the in vivo functions of AmeloD that are critical for tooth morphogenesis. We found that AmeloD-KO mice developed enamel hypoplasia and small teeth because of increased expression of E-cadherin in inner enamel epithelial (IEE) cells, and it may cause inhibition of the cell migration. We used the CLDE dental epithelial cell line to conduct further mechanistic analyses to determine whether AmeloD overexpression in CLDE cells suppresses E-cadherin expression and promotes cell migration. Knockout of epiprofin (Epfn), another transcription factor required for tooth morphogenesis and development, and analysis of AmeloD expression and deletion revealed that AmeloD also contributed to multiple tooth formation in Epfn-KO mice by promoting the invasion of dental epithelial cells into the mesenchymal region. Thus, AmeloD appears to play an important role in tooth morphogenesis by modulating E-cadherin and dental epithelial–mesenchymal interactions. These findings provide detailed insights into the mechanism of ectodermal organ development

マウスガードの使用とその外傷防止効果 : 北海道学生アメリカンフットボール選手における調査

For the prevention of sports injuries in the stomatognathic system, the use of mouthguards is strongly recommended in contact sports. The purpose of this study was to survey the incidence of sports injuries of the stomatognathic system and to investigate problems with the use of mouthguards in contact sports. Questionaires were sent to 474 university American football players in Hokkaido. There were 229 responses, and the results were as follows: 1. The rate of incidence of sports injuries was 19 percent ; and 70 precent of the injuries occured in the soft tissues and 18 percent were fractures of teeth. 2. Fifty two percent of the injuries occured during practice and 27 percent in games ; almost all injuries occured in tackle and block plays. 3. Ninty seven percent of the players were using commercially available mouthguards but only 34 percent of the players were always wearing mouthguards. Using mouthguards give rise to speaking difficulties, discomfort, and breathing difficulties, and most of the players would like to see improvements to the mouthguards. 4. The rate of incidence of injuries in the players who always wear mouthguards was 8 percent and most injuries occured in soft tissues. The rate of injuries in players who do not always wear monthguards was 25 percent and included more serious injuries. 5. The incidence of neck injuries was 17 percent and 9 percent reported concussions

Inhibitory Mechanism of Pancreatic Amyloid Fibril Formation: Formation of the Complex between Tea Catechins and the Fragment of Residues 22–27

Islet amyloid polypeptide (IAPP) is a major component of pancreatic amyloid deposits associated with type 2 diabetes. Polyphenols contained in plant foods have been found to inhibit amyloid fibril formation of proteins and/or peptides. However, the inhibition mechanism is not clear for a variety of systems. Here the inhibition mechanism of green tea polyphenols, catechins, on amyloid fibril formation of the IAPP fragment (IAPP22–27), which is of sufficient length for formation of β-sheet-containing amyloid fibrils, was investigated by means of kinetic analysis. A quartz crystal microbalance (QCM) determined that the association constants of gallate-type catechins [epicatechin 3-gallate (ECg) and epigallocatechin 3-gallate] for binding to IAPP22–27 immobilized on the gold plate in QCM were 1 order of magnitude larger than those of the free IAPP22–27 peptide, and also those of epicatechin and epigallocatechin. Kinetic analysis using a two-step autocatalytic reaction mechanism revealed that ECg significantly reduced the rate constants of the first nucleation step of amyloid fibril formation, while the rate of autocatalytic growth was less retarded. ¹H nuclear magnetic resonance studies clarified that a IAPP22–27/ECg complex clearly forms as viewed from the ¹H chemical shift changes and line broadening. Our study suggests that tea catechins specifically inhibit the early stages of amyloid fibril formation to form amyloid nuclei by interacting with the unstructured peptide and that this inhibition mechanism is of great therapeutic value because stabilization of the native state could delay the pathogenesis of amyloid diseases and also the toxicity of the small oligomer (protofibril) is reported to be greater than that of the mature fibril

Characteristics of older patients with postmenopausal osteoporosis who developed loss of muscle mass during the COVID-19 pandemic – a case–control study

Abstract Background Under the restriction of social activities during the coronavirus disease 2019 (COVID-19) pandemic, there was concern about the loss of muscle mass due to a decrease in physical activity for the elderly. The purpose of this study was to investigate the characteristics of older patients with postmenopausal osteoporosis who developed loss of muscle mass during the COVID-19 pandemic in Japan. Methods A total of 54 patients with postmenopausal osteoporosis were evaluated in this study. Whole-body dual-energy X-ray absorptiometry was performed pre- and post-COVID-19 pandemic to measure trunk and lower limb muscle mass. At the time of the post-COVID-19 pandemic, we conducted a survey to compare lifestyle before pandemic (the frequency of going out, the frequency of meeting acquaintances or families living apart, regular exercise habits, walking time, family structure), and comorbidities between the muscle mass loss (ML) group and the muscle mass maintenance (MM) group. The ML group consisted of patients with at least a 5% decrease in lower limb muscle mass or trunk muscle mass. Results A significant difference was found only for the family structure (P = 0.0279); in the ML group, those living alone were the largest group, while in the MM group they were the smallest group. Conclusions The ML group was significantly more likely to live alone than the MM group. The current study showed that loss of muscle mass was more common in patients living alone

Interaction of epicatechin gallate with phospholipid membranes as revealed by solid-state NMR spectroscopy

AbstractEpicatechin gallate (ECg), a green tea polyphenol, has various physiological effects. Our previous nuclear Overhauser effect spectroscopy (NOESY) study using solution NMR spectroscopy demonstrated that ECg strongly interacts with the surface of phospholipid bilayers. However, the dynamic behavior of ECg in the phospholipid bilayers has not been clarified, especially the dynamics and molecular arrangement of the galloyl moiety, which supposedly has an important interactive role. In this study, we synthesized [13C]-ECg, in which the carbonyl carbon of the galloyl moiety was labeled by 13C isotope, and analyzed it by solid-state NMR spectroscopy. Solid-state 31P NMR analysis indicated that ECg changes the gel-to-liquid-crystalline phase transition temperature of DMPC bilayers as well as the dynamics and mobility of the phospholipids. In the solid-state 13C NMR analysis under static conditions, the carbonyl carbon signal of the [13C]-ECg exhibited an axially symmetric powder pattern. This indicates that the ECg molecules rotate about an axis tilting at a constant angle to the bilayer normal. The accurate intermolecular–interatomic distance between the labeled carbonyl carbon of [13C]-ECg and the phosphorus of the phospholipid was determined to be 5.3±0.1Å by 13C–31P rotational echo double resonance (REDOR) measurements. These results suggest that the galloyl moiety contributes to increasing the hydrophobicity of catechin molecules, and consequently to high affinity of galloyl-type catechins for phospholipid membranes, as well as to stabilization of catechin molecules in the phospholipid membranes by cation–π interaction between the galloyl ring and quaternary amine of the phospholipid head-group