人体下颌骨的弹性

本文应用应变电测技术研究了人体下颌骨的弹性。结果表明,其力学特性与其位置,方问密切关系,说明人体下颌骨是一种各向异性的非均质的复合材料。     

骨膜在骨折愈合及骨组织修复过程中的作用

背景:骨膜因含有成骨潜能的细胞而参与骨折愈合及骨组织修复的过程,其在修复骨缺损方面的作用是目前研究的热点。目的:对骨膜在骨折愈合及骨组织修复过程中所发挥的作用进行综述。方法:第一作者应用计算机检索1964年1月至2019年12月PubMed、中国知网数据库等中英文期刊全文数据库有关骨膜在骨折愈合及骨组织修复过程中作用的文章,英文检索词periosteum,bone healing,periosteum cells;中文检索词骨膜,骨折愈合,骨膜细胞。最终选择48篇重要文献进行综述。结果与结论:①骨膜的完整性对于骨折愈合和骨组织的修复极其重要,因其较好的成骨性能、优质的材料学特性和屏障作用等特点被广泛应用于骨组织工程;②骨膜在牵拉成骨过程中的作用机制目前尚且存在争议,研究证实骨膜缺如并不会影响下颌骨缺损牵拉成骨的效果,但在四肢骨缺损牵拉成骨中的作用仍有待进一步研究。     

Cell replication in craniofacial periosteum: appositional vs. resorptive sites

The size and the shape of craniofacial bones results from periosteal activity, which can be either appositional or resorptive. The periosteum is often used as a source of graft material for osteogenesis, but differences in cellular makeup and proliferative capacity may render resorptive regions unsuitable for transplant. This study was undertaken to characterize the cells in appositional and resorptive periosteum, and to assess variation in proliferative activity. Young pigs (n=9) were injected with bromodeoxyuridine to label replicating cells and killed 3h later. The mandibular ramus, hard palate and zygomatic arch were examined for patterns of periosteal activity, and replicating cells were quantified in 16 appositional and eight resorptive regions. Sections were also reacted for markers of osteogenic (Runx2) and osteoclastic [CTR (calcitonin receptor), RANK, TRAP, CD14] lineage, and for an endothelial label (lectin). Replicating cells were often associated with the vasculature; most were unreactive for markers of differentiation. Although the fibrous layers of periosteum had fewer replicating cells per unit area than inner layers (P<0.005), this was in part due to lower cellularity. Appositional periostea differed from resorptive periostea in having thicker fibrous layers (197 vs. 89μm, P=0.02) and higher replication density in the inner layers (606 vs. 329 labeled cells mm(-2) , P=0.02). Osteoprogenitors were numerous in the inner layers of appositional but very scarce in resorptive periostea. Multinucleated osteoclasts were never seen in appositional regions, but mononuclear cells positive for osteoclastic lineage markers were plentiful, especially in the most rapidly growing areas. These cells appeared to be macrophages accompanying a growth rate so rapid as to resemble a response to trauma. In conclusion, appositional and resorptive periostea differ strikingly in morphology and cell content. Resorptive periosteum is a poor choice for osteogenic grafting.     

Comparing the Distribution of Strains with the Distribution of Bone Tissue in a Human Mandible: A Finite Element Study

Comparative anatomy and experimental studies suggest that the mass and distribution of tissue within a bone is adapted to the strains the bone experiences during function. Finite element analysis is a powerful tool that can be used to investigate this since it allows the creation of hypothetical models with unadapted morphology. Here we use FE models of a human mandible with modified internal morphology to study the relationships between the gross distribution of bone tissue (i.e., the presence or absence of bone in a certain area), the variation of cortical bone thickness within the mandible and the distribution of strain magnitudes. We created one model in which all internal cavities were filled with cortical bone material and a second, hollow model with constant cortical bone thickness. In both the models, several load cases representing bites at different positions along the tooth row were applied and peak strain magnitudes across these load cases were calculated. The peak strain distributions in both models show striking similarities with the gross distribution of bone tissue and the variation of cortical thickness in the real mandible, but the correlation coefficients are rather low. These low coefficients could be explained by confounding factors and by the limited spectrum of load cases that were simulated. However, the correspondences we find between strain magnitude and bone tissue distribution suggest that models with altered internal geometry are useful in studying the mechanical adaptation of bone, especially in the absence of any in vivo strain data. Anat Rec, 2013. © 2012 Wiley Periodicals, Inc.     

Periosteal osteosarcoma of the femur with bone marrow involvement: A case report

Periosteal osteosarcoma is an exceedingly rare type of chondroblastic osteosarcoma, showing rather better prognosis, and secondary bone marrow involvement is unusual. A case of a 22 year old male with periosteal osteosarcoma of the right femur with an associated bone marrow lesion is presented. The juxtacortical tumor, 16 ×11 × 9 cm, was located on the bone cortex of the upper diaphysis and extended into the surrounding soft tissues. A minimal bone marrow lesion was present, although the bone cortex was quite intact. Microscopically, the tumor consisted exclusively of atypical chondroblastic cells with a small osteoblastic area. The bone marrow lesion, interestingly, contained both multiple nodules of well-differentiated chondrosarcomatous components and a few demarcated foci of atypical spindle cells producing a fine osteoid matrix. It was reasonable to conclude, therefore, that this tumor was a periosteal osteosarcoma with an unusual secondary bone marrow lesion rather than a conventional (central) chondroblastic osteosarcoma with soft tissue invasion. The patients good prognosis with no tumor recurrence or metastasis during more than 7 years follow-up after surgery supports this conclusion.     

下颌骨内侧面下颌副孔的位置

目的　研究下颌副孔的位置 ,探讨肿瘤细胞向下颌骨播散的可能途径。方法　应用大体解剖方法对 82例下颌骨内侧面下颌副孔的位置进行研究并统计分析。结果　各标本之间副孔数差异很大 ,下颌副孔冠状区出现率为 5 7 3 2 %、切迹区 71 95 %、髁区 5 7 3 2 % ,上、中、下区出现率分别为 73 17% ;73 17%和98 78%。结论　下颌骨内侧面下颌副孔为口腔内肿瘤细胞播散到下颌骨的途径之一 ,未经放疗的病例应切除磨牙后区和冠状突而保留下颌骨的其余部分     

The Role of T Helper 17 Cells and Other IL-17-Producing Cells in Bone Resorption and Remodeling

In recent decades, many studies have highlighted the role of IL-17-producing cells in bone resorption. However, the importance of many IL-17-producing cell types remains largely unknown in bone remodeling. In this review, we summarize the function of IL-17-producing cells, with a focus on T helper 17 (Th17) cells, in bone resorption and remodeling.     

Radiological and Microsurgical Anatomy for Variation of the Mandible: Comparative Study of Human and Macaca fascicularis

Recent studies using cone‐beam computer tomography (CBCT) have added to our understanding of anatomical variation in the mandible of humans. However, the distribution of nerves cannot be revealed by CBCT. There have been investigations of the distribution of nerves relating to the mandible, but some proposed causes of these variations remain controversial. In this study, we observed a total of 10 sides from five mandibles of Macaca fascicularis of unknown age and sex using CBCT and dissection under stereomicroscopy. Nine of the 10 sides had two mental foramina in each side. Innervation by the mental nerves depended on the locations of those foramina. The long branch to the mandibular angle ran with a branch of the facial artery, which joined the mental artery in all 10 sides. Five specimens had a median perforating canal in the mandibular bone. In addition, a branch of the sublingual artery, which joined with the small branches of the submental artery, entered the mandibular bone from the median lingual foramen. This foramen was located in the lower part of the mandibular symphysis and passed via the median perforating canal to exit from the median labial foramen, also located in the lower part of the mandibular symphysis. We speculate that the median perforating canal of the mandible, rarely found in humans, is the remnant of the feeding artery of the fetal mandible, and in M. fascicularis is seen in all specimens because they have no mental protuberance. Anat Rec, 300:1464–1471, 2017. © 2017 Wiley Periodicals, Inc.     

The Role of Plasmacytoid and Myeloid Dendritic Cells in Induction of Asthma in a Mouse Model and the Effect of a TLR9 Agonist on Dendritic Cells

Purpose

To determine the role of plasmacytoid dendritic cells (pDC) and myeloid dendritic cells (mDC) in priming effector T cells to induce allergy, and to evaluate the effect of immunostimulatory sequences (ISS, TLR9 agonist) on dendritic cells.

Methods

Cultured mDC and pDC with/without ISS were injected intratracheally into sensitized Balb/C mice. Mice were sacrificed, and then pulmonary function tests, bronchoalveolar lavage (BAL), cell counts, and cytokine levels were evaluated. Migration of dendritic cells was also evaluated after ISS administration.

Results

In mice injected with mDC, airway hyperresponsiveness, eosinophil counts, and Th2 cytokine levels in BAL increased with increasing numbers of mDC injected. However, in mice injected with pDC, none of these changed, suggesting poor priming of T cells by pDC. In addition, mDC pulsed with ISS inhibited asthmatic reactions, and ISS administration inhibited migration of DC to the lung.

Conclusions

We suggest that pDC played a limited role in priming T cells in this asthma model and that mDC played a major role in inducing asthma. In addition, ISS inhibited migration of DC to the lung.     

The macroscopic and histomorphological properties of periosteal rib lesions and its relation with disease duration: evidence from the Luis Lopes Skeletal Collection (Lisbon,Portugal)

Periosteal new bone formation (PNBF) is a common finding in a large spectrum of diseases. In clinical practice, the morphology and location of periosteal lesions are frequently used to assist in the differential diagnosis of distinct bone conditions. Less commonly reported is the presence of PNBF on the ribs. This contrasts with the data retrieved from the study of skeletonized human remains that shows a high frequency of cases and a strong, albeit not specific, association between periosteal rib lesions and pulmonary conditions (e.g. tuberculosis). Despite that, an overall disagreement regarding the specificity and non‐specificity of periosteal reactions exists in the study of dry bone remains. The insufficient number of clinical models exploring the morphology and the pathophysiology of PNBF's and the lack of systematic studies of pathological samples with a known diagnosis are claimed as major reasons for the disagreements. This study aimed to describe and compare the macroscopic and the histomorphologic appearance of periosteal rib lesions and to discuss their usefulness as diagnostic indicators. To pursue this goal, an assemblage of 13 rib samples (males = 11, females = 2, mean age‐at‐death = 36.6 years old) was collected from the Luis Lopes Skeletal Collection (Museu Nacional de História Natural e da Ciência, Universidade de Lisboa, Portugal). The assemblage belongs to individuals who died from pulmonary‐TB (group 1), non‐TB pulmonary infections (group 2) and other conditions (group 3). Prior to sample preparation, the ribs were visually inspected and the PNBF described according to its thickness, the degree of cortical integration and the type of new bone formed (e.g. woven, lamellar or both). After sampling, each bone sample was prepared for histological analysis under plane and polarized light microscopy. Macroscopically, the results showed no differences in the new bone composition between cause‐of‐death groups. Only slight differences in the degree of cortical integration, which was most frequently classified as mild to high in the pulmonary‐TB group, were observed. Histologically, no distinguishing features were identified by pathological group. However, new bone microarchitectures were observed compatible with (1) acute, fast‐growing processes (e.g. spiculated reactions), (2) long‐standing processes with a rapid bone formation (e.g. appositional layering of bone) and/or (3) chronic, slow‐growing processes (e.g. layers of compact lamellae). To some extent, these distinct rates of disease progression resonate with the cause‐of‐death listed for some individuals. Despite the small sample size, the results of this investigation are in agreement with previous studies, according to which the macroscopic and histological appearance of periosteal formations are not specific for a particular pathological conditions. Nevertheless, the results support the conclusion that the morphology of periosteal lesions is a good biological indicator for inferring the rate of progression and duration of pathological processes. This study provides important reference data regarding the histomorphology of periosteal lesions that can be used for comparative purposes, as well as to narrow down the differential diagnosis in unidentified skeletal remains.     

下颌管位置与下颌支矢状劈开术的关系

在50侧成人下颌骨的切面上,观察测量了下颌管在下颌支矢状截骨术的位置,下颌管至下颌骨内、外侧面,上、下缘的距离等。从解剖学角度讨论了术中防止下齿槽神经损伤的要点。     

Intravenous transplantation of allogeneic bone marrow mesenchymal stem cells and its directional migration to the necrotic femoral head

In this study, we investigated the feasibility and safety of intravenous transplantation of allogeneic bone marrow mesenchymal stem cells (MSCs) for femoral head repair, and observed the migration and distribution of MSCs in hosts. MSCs were labeled with green fluorescent protein (GFP) in vitro and injected into nude mice via vena caudalis, and the distribution of MSCs was dynamically monitored at 0, 6, 24, 48, 72 and 96 h after transplantation. Two weeks after the establishment of a rabbit model of femoral head necrosis, GFP labeled MSCs were injected into these rabbits via ear vein, immunological rejection and graft versus host disease were observed and necrotic and normal femoral heads, bone marrows, lungs, and livers were harvested at 2, 4 and 6 w after transplantation. The sections of these tissues were observed under fluorescent microscope. More than 70 % MSCs were successfully labeled with GFP at 72 h after labeling. MSCs were uniformly distributed in multiple organs and tissues including brain, lungs, heart, kidneys, intestine and bilateral hip joints of nude mice. In rabbits, at 6 w after intravenous transplantation, GFP labeled MSCs were noted in the lungs, liver, bone marrow and normal and necrotic femoral heads of rabbits, and the number of MSCs in bone marrow was higher than that in the, femoral head, liver and lungs. Furthermore, the number of MSCs peaked at 6 w after transplantation. Moreover, no immunological rejection and graft versus host disease were found after transplantation in rabbits. Our results revealed intravenously implanted MSCs could migrate into the femoral head of hosts, and especially migrate directionally and survive in the necrotic femoral heads. Thus, it is feasible and safe to treat femoral head necrosis by intravenous transplantation of allogeneic MSCs.     

Maternal environment and craniofacial growth: geometric morphometric analysis of mandibular shape changes with in utero thyroxine overexposure in mice

An estimated 3% of US pregnancies are affected by maternal thyroid dysfunction, with between one and three of every 1000 pregnancies being complicated by overactive maternal thyroid levels. Excess thyroid hormones are linked to neurological impairment and excessive craniofacial variation, affecting both endochondral and intramembranous bone. Using a geometric morphometric approach, this study evaluates the role of in utero thyroxine overexposure on the growth of offspring mandibles in a sample of 241 mice. Canonical variate analysis utilized 16 unilateral mandibular landmarks obtained from 3D micro‐computed tomography to assess shape changes between unexposed controls (n = 63) and exposed mice (n = 178). By evaluating shape changes in the mandible among three age groups (15, 20 and 25 days postnatal) and different dosage levels (low, medium and high), this study found that excess maternal thyroxine alters offspring mandibular shape in both age‐ and dosage‐dependent manners. Group differences in overall shape were significant (P < 0.001), and showed major changes in regions of the mandible associated with muscle attachment (coronoid process, gonial angle) and regions of growth largely governed by articulation with the cranial base (condyle) and occlusion (alveolus). These results compliment recent studies demonstrating that maternal thyroxine levels can alter the cranial base and cranial vault of offspring, contributing to a better understanding of both normal and abnormal mandibular development, as well as the medical implications of craniofacial growth and development.     

淫羊藿苷治疗骨不连的分子机制

文题释义：骨不连：骨组织具有强大的自我修复能力,给予适当治疗后大多数骨折都会很快很好地愈合。然而,仍有一小部分骨折难以愈合,当骨折超过3个月仍未愈合,称为延迟愈合,当骨折超过9个月仍未达到骨性连接,则称为骨不连。淫羊藿苷：为淫羊藿干燥茎叶的提取物,呈淡黄色针状结晶粉末,相对分子质量为676.65,属黄酮类化合物,现代药理学研究发现其具有很强的生物活性,对骨组织、免疫系统、肿瘤组织、神经系统、生殖系统、内分泌系统和心血管系统等具有显著作用。背景：骨不连是骨科临床上常见的并发症,严重影响患者的身心健康和生活质量。近年来大量的研究发现淫羊藿苷在促进骨折愈合和治疗骨缺损方面有着显著作用;骨不连和骨折愈合是对立共存的,有关骨折愈合机制的研究实际上就是治疗骨不连的研究。目的：综述淫羊藿苷在骨不连治疗过程中的分子机制研究进展。方法：第一作者应用计算机以“icariin,bone nonunion,bone marrow mesenchymal stem cells,periosteal cell,osteoblasts,osteoclast”及“淫羊藿苷、骨不连、骨髓间充质干细胞、骨膜细胞、成骨细胞、破骨细胞”作为主题词检索PubMed、中国知网、万方、维普数据库,共检索到542篇文献,按入选标准及排除标准进行筛选,最终纳入44篇文献。结果与结论：淫羊藿苷通过促进骨髓间充质干细胞和骨膜细胞增殖及向成骨细胞分化、促进成骨细胞增殖与成熟、抑制破骨细胞的破骨作用,有效促进骨折愈合和治疗骨不连。目前绝大部分研究仍处于基础实验阶段,尚需要大量临床研究,对于相关蛋白及基因方面也有待于进一步研究,希望为骨不连的中药治疗提供新思路。ORCID: 0000-0002-2013-743X(余绍涌)中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

基质刚度调节细胞-细胞外基质间黏附对肿瘤细胞迁移影响的模型研究

目的 研究细胞外基质(extracellular matrix,ECM)刚度对细胞和ECM间黏附及肿瘤迁移的影响.方法 建立基于网状波茨模型(cellular Potts model,CPM),模拟肿瘤细胞生长与细胞间免疫反馈过程,观察细胞力学行为改变对细胞-ECM黏附的影响状况,分析不同ECM下肿瘤细胞迁移的变化.结...     

Morphological Changes in the Mandible of Male Mice Associated With Aging and Biomechanical Stimulus

Degenerative changes in the temporomandibular joint (TMJ) associated with aging can affect mandibular shape and reduce growth potential when stimulated by functional appliance therapy. This study was designed to evaluate the morphological changes in the mandibles of male mice associated with aging and biomechanical stimulus. Every 3 days over the course of 1 month, the lower incisors were trimmed by 1 mm to induce mandibular advancement (MA) when the animal was feeding. The left mandibles of the 23 experimental and 27 control animals were subsequently dissected, and digital images were obtained to analyze nine linear/angular measurements. Because mandibular morphology depends on the maintenance of condylar cartilage, the surfaces of the condylar cartilage and the ascending ramus of the mandible were also analyzed by scanning electron microscopy (SEM). The linear measurements of the mandible showed changes according to age in the control group and a growth response in the mandibular condyle in 7‐ and 15‐month‐old mice after MA. Moreover, SEM analysis revealed depressions in the anterior region of the condylar cartilage and inclined vascular grooves in the ascending ramus in the 7‐ and 15‐month‐old experimental mice. Although the growth potential is reduced in mice after 6 months of age, the results showed that continuous growth of the mandible occurs after maturation, except in the condyle, and that biomechanical stimulus of the TMJ of male mice leads to condylar growth. These results suggest that mature and old individuals can favorably respond to maxillary functional orthopedic therapy. Anat Rec, 292:431–438, 2009. © 2009 Wiley‐Liss, Inc.     

The Potential Role of Platelet-Derived Growth Factor as an Autocrine or Paracrine Factor for Human Bone Cells

Platelet-derived growth factor, PDGF, is a potent mitogen for cells of mesenchymal origin such as fibroblasts, smooth muscle cells and glial cells. PDGF is thought to have the potential to act as both a paracrine and an autocrine factor. Studies described here extend these observations to human bone-derived cells. Exogenous PDGF induces biologic activity in two human osteogenic sarcoma cell lines and in one of these, the two PDGF genes, PDGF-1 and PDGF-2/c-sis are expressed. In addition, PDGF stimulates proliferation of normal osteoblastic cells derived from adult human cancellous bone. The expression of the PDGF-1 gene but not the PDGF-2/c-sis gene is demonstrated in normal human adult bone-derived cells by Northern blot analysis and synthesis of PDGF is shown by immunoprecipitation with PDGF antisera. These studies indicate that PDGF has the potential to act as a paracrine or autocrine regulator of bone cells.     

Thymic Dendritic Cells: Phenotype and Function

Interdigitating (IDC) cells of the thymus have been characterized in situ by their ultrastructure and phenotype. Thymic dendritic cells (DC), thought to represent their in vitro correlate, resemble splenic DC in their ability to initiate peripheral T cell responses. In vivo, however, DC of the thymus have been implicated in tolerance induction, although at one time they were thought to impart MHC-restriction on developing T cells. Our present understanding of these areas is reviewed here.

An in vitro model has been developed to address directly the function of DC in the thymus. Mature DC and immature thymocytes migrate into deoxyguanosine-treated thymus lobes where they adopt a reciprocal distribution, DC homing primarily to the medulla while the thymocytes remain in the cortex. These observations support the close relationship between thymic DC and IDC and provide a powerful tool to examine the role of DC in thymocyte ontogeny.