复合结构组织工程化人工骨的金属支架结构设计研究?

支架结构设计是组织工程化人工骨设计的重要内容之一,本文对金属与陶瓷材料构成的复合结构人工骨中金属支架的设计进行了研究。通过对髋关节置换后假体与股骨之间力的传递规律进行数值模拟研究,采用分截面分析、网格密度逐渐减小的设计方法,对复合结构人工骨中的金属支架结构进行了设计。通过对6种不同网格密度金属支架的受力情况进行对比分析,设计出了力学特性符合股骨受力规律的金属支架结构。     

去卵巢大鼠骨元素代谢紊乱机制研究

测定了去卵巢大鼠骨元素含量和血清相关激素和细胞因子含量,分析了去卵巢大鼠骨元素代谢紊乱的机制。将健康4月龄SD大鼠18只随机分成3组：正常对照组,假去卵巢大鼠组和去卵巢大鼠组。结果表明,去卵巢大鼠骨Ca、Mg、S、Mn、Zn等含量显著降低,P含量显著升高,血清E2、P、CT、GH等含量显著降低,IL-6、FSH、LH等含量显著升高。提示去卵巢大鼠骨元素代谢紊乱是雌激素水平下降与其他因素共同作用的结果。     

Effects of time delays in a mathematical bone model

In this paper we propose a mathematical model of bone remodeling with time delays of both osteoclast-derived paracrine signaling of tumor and tumor-derived paracrine signaling of osteoclast. The effects of time delays on the growth of tumor cells and bone system are studied in multiple myeloma-induced bone disease. In the case of small osteoclast-derived paracrine signaling, it is found that the growth of tumor cells slows down, the oscillation period of the ratio of osteoclasts to osteoblasts is extended with increasing time delay, and there is a competition between the delay and osteoclast-derived paracrine signaling. In the case of large tumor-derived paracrine signaling, the tumor-derived paracrine signaling can induce a more significant decline in tumor growth for long time delay, and thus slowing down the progression of bone disease. There is an optimal coupling between the tumor-derived paracrine signaling of osteoclasts and time delay during the progressions of bone diseases, which suppresses the tumor growth and the regression of bone disease.     

Vitamin D Fortification of Consumption Cow’s Milk: Health,Nutritional and Technological Aspects. A Multidisciplinary Lecture of the Recent Scientific Evidence

Vitamin D is essential in assuring bone health at all stages of life, but its non-skeletal effects are also essential: This vitamin impacts the physiology of the immune system, skeletal muscles and adipose tissue, glucose metabolism, skin, cardiovascular and reproductive systems, neuro-cognitive functions and cell division. The incidence of vitamin D deficiency is widespread worldwide, at any age, in young and healthy subjects, as well as in pregnant women and the elderly population, due to several factors, including inadequate sunlight exposure, skin pigmentation and coverage, adiposity, lifestyle and low dietary intakes. To overcome this problem, the fortification of foods that are consumed on a daily basis, such as milk, is strongly advisable. This opinion paper aims to discuss, in a multidisciplinary way, the current evidence supporting the importance of vitamin D in health and disease and the role of milk as an optimal carrier of this vitamin, to promote adequate intakes, highlighting its unique physico-chemical characteristics linked to both fat globule membrane and casein micelle structure. Moreover, it addresses the impact of industrial processing and storage of consumption milk on the stability of these structures, thus in determining vitamin D bioavailability and the achievement of adequate intakes.     

骨的微量元素代谢

雌激素可通过影响骨骼细胞的新陈代谢而促进微量元素在骨骼中的储存,微量元素代谢与骨质疏松的形成发展有密切关系。近年来不少学者对一些必需微量元素如硼(5B)、氟(9F)、钒(23V)、锰(25Mn)、铁(26Fe)、钴(27Co)、铜(29Cu)、锌(30Zn)、硒(34Se)、锶(38Sr)等和一些非必需微量元素如铝(13Al)、镓(31Ga)、锗(32Ge)、镉(48Cd)、铅(82Pb)等与骨质疏松关系的研究取得了令人瞩目的成果。     

显微红外光谱法研究豚鼠膝关节软骨下骨的增龄性改变

应用显微FTIR技术原位分析雌性Hartley豚鼠随月龄增加胫骨关节软骨下骨的化学变化。红外光谱测定三种月龄(1月、2月和3月)豚鼠软骨下3个不同吸收颜色的骨小梁区(a,b,c)和中央骨髓区(d)。结果显示：(1)随月龄增加,骨小梁总面积增加,与正常骨小梁谱图相似的a区减少,d区波形有逐渐向a区发展的趋势。(2)2月龄和3月龄的b和c区AmideⅢ红移以c区红移显著并且变成肩峰,代表核酸和多糖的吸收峰峰强是a区的7倍。(3)三种月龄的c区均出现了β型糖苷键吸收峰。(4)I_AmideⅠ/I_AmideⅡ在2月b区最大,3月各区最小,I_AmideⅢ/I_AmideⅡ 在 2月、3月由a到c依次降低,I_νsPO-₂/I_AmideⅡ在2月、3月的b和c区较相应a区高7倍以上。结果符合骨关节炎不同阶段软骨下骨的组织结构及化学组成的变化规律。初步研究表明,显微光谱成像技术结合FTIR可原位分析不同区域的软骨下骨小梁和骨髓的分子组成,为骨关节炎软骨下骨组织病理学的分子水平研究提供了可靠信息。     

明胶溶液中沉淀法制备纯相β-磷酸三钙

本文以明胶、硝酸钙Ca(NO₃)₂和磷酸氢二铵(NH₄)₂HPO₄为前驱体,初始Ca/P为1.5,制备了纯相的β-磷酸三钙.红外谱图和X射线晶体衍射结果表明,溶液中直接沉淀得到的产物为缺钙磷灰石,该产物在明胶浓度≥0.22 %(质量分数)时热转化为纯相的β-磷酸三钙.通过晶体尺寸计算和比表面积测定,缺钙磷灰石的晶体大小随着明胶用量的增加而变小.透射电镜结果显示溶液中直接沉淀的缺钙磷灰石呈针状形貌,经过高温煅烧后,针状的缺钙磷灰石将相互融合形成葡萄状的β-磷酸三钙.差热/热重结果表明,明胶与生成的缺钙磷灰石形成了化学键合,这将有助于吸附较多的水分子,随后水分子与缺钙磷灰石发生化学反应生成羟基磷灰石,羟基磷灰石继续与沉淀中的偏磷酸钙反应生成β-磷酸三钙.本文还研究了明胶对纯相β-磷酸三钙的生成机理.     

Microstructures and properties of cancellous bone of avascular necrosis of femoral heads

The aim of this study is to investigate microscopic structure and characterize cancellous bone of avascular necrosis of the femoral head （ANFH）. The rabbit model of the ANFH is established. The histopathologic features are studied successfully. The differences between the steroidinjection group （S.G.） and the controlled group （C.G.） are examined, including the weight of rabbits, the hematological examination and the three-dimensional stnactures. It is found that the plasma levels of cholesterol （CHO）, high-density lipoprotein （HDL） and low-density lipoprotein （LDL） in S.G. are lower than those in C.G. when the triglyceride （TG） increased in the S.G.; but the bone mineral content （BMC） and the structural model index （SMI） of the organ and tissue decreased significantly in S.G. Three-dimensional structures of the femoral head are obtained using micro-computed tomography （CT） scanning and the mechanical model is established to analyze the influences of these structural changes on the mechanical properties of the cancellous bone.     

3D and Porous RGDC‐Functionalized Polyester‐Based Scaffolds as a Niche to Induce Osteogenic Differentiation of Human Bone Marrow Stem Cells

Polyester‐based scaffolds covalently functionalized with arginine‐glycine‐aspartic acid‐cysteine (RGDC) peptide sequences support the proliferation and osteogenic differentiation of stem cells. The aim is to create an optimized 3D niche to sustain human bone marrow stem cell (hBMSC) viability and osteogenic commitment, without reliance on differentiation media. Scaffolds consisting of poly(lactide‐co‐trimethylene carbonate), poly(LA‐co‐TMC), and functionalized poly(lactide) copolymers with pendant thiol groups are prepared by salt‐leaching technique. The availability of functional groups on scaffold surfaces allows for an easy and straightforward method to covalently attach RGDC peptide motifs without affecting the polymerization degree. The strategy enables the chemical binding of bioactive motifs on the surfaces of 3D scaffolds and avoids conventional methods that require harsh conditions. Gene and protein levels and mineral deposition indicate the osteogenic commitment of hBMSC cultured on the RGDC functionalized surfaces. The osteogenic commitment of hBMSC is enhanced on functionalized surfaces compared with nonfunctionalized surfaces and without supplementing media with osteogenic factors. Poly(LA‐co‐TMC) scaffolds have potential as scaffolds for osteoblast culture and bone grafts. Furthermore, these results contribute to the development of biomimetic materials and allow a deeper comprehension of the importance of RGD peptides on stem cell transition toward osteoblastic lineage.     

Modeling Methyl Methacrylate (MMA) Polymerization for Bone Cement Production

Bone cements based on poly(methyl methacrylate) (PMMA) have been widely used in orthopedic surgeries for fixation of prostheses and filling of bone defects. Bone cements are produced through in situ and in vivo free radical bulk polymerizations, which are highly exothermic and are subject to strong gel and glass effects. As a consequence, high temperatures may be reached during application. Furthermore, residual monomer usually remains unreacted inside the body and may cause aseptic loosening and tissue damages. 1 In a companion work in this volume, it was shown that usual free-radical polymerization models might effectively describe the bone cement preparation 2 and therefore be used for quantitative analysis of the bone cement synthesis. In this work, a theoretical investigation based on a multicell reactor model is performed to study the bone cement production and allow for future optimization of the preparation procedure. It is shown that the degree of solubility of the pre-polymer powder in the liquid monomer is the most important variable during the bone cement preparation and that this variable should be manipulated for design and control of the operation in real applications.