Insulin resistance and diabetes combine to impair mitochondrial oxidative metabolism and cause lipid accumulation in non-adipose tissues such as skeletal muscles and the liver. The thyroid hormone stimulates thermogenesis, mitochondrial biogenesis, and various metabolisms, including gluconeogenesis and fatty-acid oxidation. Therefore, altered thyroid hormone action may induce the mitochondrial phenotype associated with insulin resistance. This review focuses on the correlation between thyroid hormone function and diabetes and the possible mechanisms associated with intracellular thyroid hormone dysfunction due to impaired metabolism.
Gluconeogenesis ; Insulin ; Insulin Resistance ; Liver ; Organelle Biogenesis ; Muscle, Skeletal ; Phenotype ; Thermogenesis ; Thyroid Gland

Brown adipose generates heat via oxidation of fatty acids by a mitochondrial uncoupling protein 1 (UCP1)-dependent process. In addition, a subpopulation of cells within subcutaneous white adipose tissue, known as beige adipocytes, also plays a role in thermogenesis. The biogenesis of beige adipocytes is induced by thermogenic signals, such as chronic cold exposure. Recently, it has been reported that eosinophils, type 2 cytokines of IL-4/13, and alternatively activated macrophages control the thermogenic cycle of beige adipocytes. Alternatively, activated macrophages induce UCP1+ beige adipocytes through secretion of catecholamines. These results define the role of type 2 immune responses in the regulation of energy homeostasis.
Adipocytes ; Adipose Tissue, Brown ; Adipose Tissue, White ; Organelle Biogenesis* ; Catecholamines ; Cytokines ; Eosinophils* ; Fatty Acids ; Homeostasis ; Hot Temperature ; Macrophages* ; Thermogenesis

Dental implant may be immediately placed in postextraction socket which has alveolar bone defect. The purpose of this study was to compare the bone regeneration and bone quality around defects adjacent to implants that were placed into extraction sockets according to EFEB, GTAM barrier and GTAM barrier with DFDB. Mandibular P2, P3 and P4 were extracted bilaterally in dogs, and buccal defects were created about 4mm in depth and 3.3mm in width. Screwed pure titanium implants, 3.8mm in diameter and 10mm in length, were placed into the extraction sockets. The experimental groups were divided into four groups : the G group was covered with a GTAM barrier on the defective area, the D+G group was filled with DFEB and covered with a GTAM barrier, the D group was filled with DFDB only and the control group was sutured without any special treatment on the defective area. The experimental animals were killed after 12 weeks and specimens were prepared for light microscopic evaluation and fluorescent dyes were administered daily for 2 weeks after implantation, and injected on the 4th and 11th week for fluorescent microscopic examination to observe new bone formation and bone remodeling. The new Bone height of the buccal defect was measured and compared with the another for bone gain and the removal torque for the implant was measured for the comparison of bone density and bone-implant osseointegration. Results obtained were as follows : 1. Experimental groups showed bone regeneration in oder from D+G, G, D group and control. D+G and G group was significantly from D group and control(P<0.01). 2. In the defective area of control the regenerated alveolar bone showed poorly developed lamellated structure and fibrous tissue intervention into the bone-implant interface but the others showed well developed lamellated structure and osseointegration. 3. All implant groups showed no significant difference in the removal torque for implant(P>0.05) These results suggest that immediate implants placed in defective sockets were successfully osseointegrated and utilizing placed in defective sockets were successfully osseointegrated and utilizing not only the combination of GTAM and DFDB but also only the GTAM was favorable for the predictable regeneration of the defective area.
Animals ; Bone Density ; Bone Regeneration* ; Bone Remodeling ; Dental Implants ; Dogs ; Fluorescent Dyes ; Osseointegration ; Osteogenesis ; Regeneration ; Titanium ; Torque

The current interest in periodontal tissue regeneration has lead to research in bone graft, root surface treatments, guided-tissue regeneration, and the administration of growth factors as possible means of regenerating lost periodontal tissue. Several studies have shown that a strong correlation between platelet-rich plasma and the stimulation of remodeling and remineralization of grafted bone exists, resulting in a possible increase of 15-30% in the density of bone trabeculae. The purpose of this study was to study the histopathological correlation between the use of platelet-rich plasma and a bone xenograft used in conjunction with a non-resorbable guided-tissue membrane, e-PTFE, compared to a control group with regards to bone regeneration at the implant fixture site. Implant fixtures were inserted and graft materials placed into the left femur of in the experimental group, while the control group received only implant fixtures. In the first experimental group, platelet-rich plasma and BBP xenograft were placed at the implant fixture site, and the second experimental group had platelet-rich plasma, BBP xenograft, and the e-PTFE membrane placed at the fixture site. The degree of bone regeneration adjacent to the implant fixture was observed and compared histopathologically at 2, 4, and 8 weeks after implant fixture insertion. The results of the experiment are as follows: 1. The rate of osseointegration to the fixture threads was found to be greater in the first experimental group compared to the control group. 2. The histopathological findings of the second experimental group showed rapid resorption of BBP with subsequent new bone formation replacing the resorbed BBP. 3. The second experimental group showed new bone formation in the area adjacent to the fixture threads beginning two weeks after fixture implantation, with continued bone remodeling in the areas mesial and distal to the fixture. 4. Significant new bone formation and bone remodeling was observed in both experimental groups near the implant fixture sites. 5. The rate of osseointegration at the fixture threads was greater in the second experimental group compared to the first group, and the formation of new bone and trabeculae around the fixture site occurred after the fourth week in the second experimental group. The results of the experiment suggest that a greater degree of new bone formation and osseointegration can occur at the implant fixture site by utilizing platelet-rich plasma and bone xenografts, and that these effects can be accelerated and enhanced by concurrent use of a non-resorbable guided tissue membrane.
Bone Regeneration ; Bone Remodeling ; Dental Implants* ; Femur ; Heterografts ; Intercellular Signaling Peptides and Proteins ; Membranes ; Osseointegration ; Osteogenesis ; Platelet-Rich Plasma* ; Regeneration* ; Transplants

The current interest in periodontal tissue regeneration has lead to research in bone graft, root surface treatments, guided-tissue regeneration, administration of growth factors, and the use of enamel matrix protein as possible means of regenerating lost periodontal tissue. Several studies have shown that a strong correlation between platelet-rich plasma and the stimulation of remodeling and remineralization of grafted bone exits, resulting in a possible increase of 15-30% in the density of bone trabeculae. The purpose of this study was to study the histopathological results and differences between the use of platelet-rich plasma and the use of enamel matrix protein(Emdogain?) about bone regeneration at the implant. Implant fixtures were inserted and graft materials placed into the left femur in the experimental group, while the only implant fixtures placed in the control group. In the first experimental group, platelet-rich plasma and xenograft were placed at the supracrestally placed implant site, and in the second experimental group, Emdogain(R) and xenograft placed at the supracrestally placed fixture site. The degree of bone regeneration adjacent to the implant fixture was observed and compared histopathologically at 2, 4, and 8 weeks after implant fixture insertion. The results of the experiment are as follows: 1. The rate of osseointegration to the fixture threads was found to be greater in the experimental group compared to in the control group. 2. The histopathological findings showed that the bone regeneration, the partial osseointegration existed at 4 weeks, and that osseointegration and bone density increaced in the experimental groups at 8 weeks. 3. The results showed that new bone formation and bone remodeling increased in the area near to the fixture in the first and second experimental groups at 8 weeks than at 4 weeks. The results showed that in the area distant from the fixture, new bone formation did not increase and bone remodeling decreased in the first experimental group at 4, 8 weeks, and that new bone formation increased in the second experimental group. 4. The histopathological findings showed that AZ deposition in the first experimental group was remarkable at 2, 8 weeks, and in the second experimental group at 2, 4, 8 weeks in the area distant from the fixture threads.
Bone Density ; Bone Regeneration* ; Bone Remodeling ; Dental Enamel* ; Dental Implants* ; Femur ; Heterografts ; Intercellular Signaling Peptides and Proteins ; Osseointegration ; Osteogenesis ; Platelet-Rich Plasma* ; Regeneration ; Staphylococcal Protein A ; Transplants

PURPOSE: The aim of the present study was to evaluate the effectiveness of using a mineralized bone cortical allograft (MBCA), with or without a resorbable collagenous membrane derived from bovine pericardium, on alveolar bone remodeling after immediate implant placement in a dog model. METHODS: Six mongrel dogs were included. The test and control sites were randomly selected. Four biradicular premolars were extracted from the mandible. In control sites, implants without an allograft or membrane were placed immediately in the fresh extraction sockets. In the test sites, an MBCA was placed to fill the gap between the bone socket wall and implant, with or without a resorbable collagenous membrane. Specimens were collected after 1 and 3 months. The amount of residual particles and new bone quality were evaluated by histomorphometry. RESULTS: Few residual graft particles were observed to be closely embedded in the new bone without any contact with the implant surface. The allograft combined with a resorbable collagen membrane limited the resorption of the buccal wall in height and width. The histological quality of the new bone was equivalent to that of the original bone. The MBCA improved the quality of new bone formation, with few residual particles observed at 3 months. CONCLUSIONS: The preliminary results of this animal study indicate a real benefit in obtaining new bone as well as in enhancing osseointegration due to the high resorbability of cortical allograft particles, in comparison to the results of xenografts or other biomaterials (mineralized or demineralized cancellous allografts) that have been presented in the literature. Furthermore, the use of an MBCA combined with a collagen membrane in extraction and immediate implant placement limited the extent of post-extraction resorption.
Allografts* ; Alveolar Bone Loss ; Animals ; Bicuspid ; Biocompatible Materials ; Bone Regeneration ; Bone Remodeling ; Collagen ; Dental Implants ; Dogs* ; Heterografts ; Mandible ; Membranes ; Miners* ; Osseointegration ; Osteogenesis ; Pericardium ; Tooth Extraction ; Transplants

Implant success is achieved by the synergistic combination of numerous biomechanical factors. This report examines the mechanical aspect of implants. In particular, it is focused on macrodesign such as thread shape, pitch, width and depth, and crestal module of implants. This study reviews the literature regarding the effect of implant thread geometry on primary stability and osseointegration under immediate loading. The search strategy included both in vitro and in vivo studies published in the MEDLINE database from January 2000 to June 2014. Various geometrical parameters are analyzed to evaluate their significance for optimal stress distribution, implant surface area, and bone remodeling responses during the process of osseointegration.
Bone Remodeling ; Dental Implants ; Osseointegration*

OBJECTIVES: To validate a critical-size mandibular bone defect model in miniature pigs. MATERIALS AND METHODS: Bilateral notch defects were produced in the mandible of dentally mature miniature pigs. The right mandibular defect remained untreated while the left defect received an autograft. Bone healing was evaluated by computed tomography (CT) at 4 and 16 weeks, and by micro-CT and non-decalcified histology at 16 weeks. RESULTS: In both the untreated and autograft treated groups, mineralized tissue volume was reduced significantly at 4 weeks post-surgery, but was comparable to the pre-surgery levels after 16 weeks. After 16 weeks, CT analysis indicated that significantly greater bone was regenerated in the autograft treated defect than in the untreated defect (P=0.013). Regardless of the treatment, the cortical bone was superior to the defect remodeled over 16 weeks to compensate for the notch defect. CONCLUSION: The presence of considerable bone healing in both treated and untreated groups suggests that this model is inadequate as a critical-size defect. Despite healing and adaptation, the original bone geometry and quality of the pre-injured mandible was not obtained. On the other hand, this model is justified for evaluating accelerated healing and mitigating the bone remodeling response, which are both important considerations for dental implant restorations.
Autografts ; Bone Regeneration ; Bone Remodeling ; Dental Implants ; Hand ; Mandible ; Swine*

A new method for the simulation of the mass distribution of cancellous bone is presented on the basis of finite element analysis (FEA). In this method,the process of bone remodelling is considered as a process of the topology optimization of a corresponding continuum structure. Fabric tensor is used to express the microstructure and the constitutive properties of cancellous bone. The effective volume fraction or the relative density of a point in the design domain is expressed by the invariables of the fabric tensor. A reference strain interval, which is corresponding to the strain dead zone of a bone in biomechanics, is applied to detect the the final topology of the structure. By the present approach, several numerical results are given, i. e., the simulation on the shape of the coronal plane of vertebrae, the predictions of the mass distributions of the two-dimensional and the three-dimensional proximal femurs. The validity and feasibility of this new method are verified by the comparison between the results of the present work and those in the published literatures.
Adaptation, Physiological ; Algorithms ; Biomechanical Phenomena ; Bone Density ; physiology ; Bone Remodeling ; physiology ; Bone and Bones ; physiology ; Computer Simulation ; Femur Head ; physiology ; Finite Element Analysis ; Humans ; Models, Biological ; Stress, Mechanical

In this paper, combined with the finite element (FE) method and optimization theory, a strain energy criterion is used to simulate and predict the bone remodeling. The strain energy density is taken as the mechanical stimulus. The bone remodeling is described as the changes of material distribution, which can represent the process of bone remodeling. By remodeling simulation of a two-dimensional proximal femur, a three-dimensional proximal femur and bone fracture healing plastic process, we demonstrate that this criterion can produce a realistic apparent density distribution in the proximal femur, and this criterion can well illuminate the mechanism of bone fracture healing plastic process.
Adaptation, Physiological ; physiology ; Biomechanical Phenomena ; Bone Remodeling ; physiology ; Bone and Bones ; physiology ; Computer Simulation ; Femur ; physiology ; Finite Element Analysis ; Humans ; Models, Biological ; Stress, Mechanical