首页 > 文献资料
-
早产儿骨代谢的影响因素及实验室评价
体内99%的钙存在于骨骼中,血循环中钙含量不到体内总量的1%.胎儿期,80%钙、磷的蓄积出现在孕25周到足月,在此期间,体内钙以2.3~2.98 mmol/(kg*d)、磷以1.9~2.39 mmol/(kg*d)的速率增加,峰蓄积率出现在孕 36~38周,足月时,体内总钙可达28 g,磷达16 g[1].早产儿由于体内骨矿物质储备较少,生长速率较快,所以易患骨质疏松及佝偻病.胎龄越小、出生体重越低,骨矿物质储备越少.有研究发现,胎龄(31±1.5)周的早产儿,出生时骨矿物质含量(bone mineral content,BMC)及骨宽度 ( bone width, BM )均明显低于足月儿[2].出生体重小于1 000 g的极低体重儿中,50%将发生骨质疏松,70%可发生骨折[1],早产儿的骨矿化到出生1年才接近正常,有的可延续到儿童期[3].
-
改良法制备异种脱蛋白骨复合重组人骨形态发生蛋白支架修复长骨大段骨缺损
BACKGROUND: For its extensive sources and specific biological characteristics, heterogeneous deproteinized bone (DPB) as the tissue-engineered scaffold material gets a good application prospect in repair of large segmental bone defects.OBJECTIVE: To prepare scaffold material by compositing modified heterogeneous DPB with recombinant human bone morphogenetic protein 2 (rhBMP2) and evaluate the osteogenic ability in repairing large segmental long bone defects in large-sized animals.METHODS: Twenty-four goats were randomly and evenly divided into three groups: DPB, autologous bone, and DPB+rhBMP2. Bone defects (20% in length) were made in the middle and lower segments of the right tibia of each goat, and according to group design,different bone grafts were implanted and fixed using semi-ring slot external fixer. At 4-24 weeks after surgery, X-ray examination was performed once every other 4 weeks. At 24 weeks after surgery, newly formed bones were taken out for determining the repair effects of bone defects through duat-energy X-ray analysis, histological observation, and biomechanical analysis.RESULTS AND CONCLUSION: The prepared DPB exhibited a three-dimensional porous structure, with a porosity of (78.5±6.45)% and pore size of (472.5±7.02) μm. Time-dependent bone repair was found in each group. Results regarding anti-compression test, three-point anti-bend test, and anti-torsion test were greatest in the autologous bone group, followed by the DPB+rhBMP2 group, and lastly the DPB group. There were no significant differences in tibial bone density, bone mineral content,anti-compression pressure and ultimate pressure, anti-bending load and ultimate toad, anti-torsion torque and ultimate torque between autologous bone group, DPB+rhBMP2 group and normal bone control group. These findings indicate that modified heterogeneous DPB composited with rhBMP2 has osteogenic ability equivalent to autologous bone in repairing large segmental long bone defects in goat tibias. Therefore, it can be applied as tissue-engineered scaffold material.
-
性激素替代治疗在预防和治疗绝经后骨质疏松症中的应用
妇女健康研究(Women's Health Initiative,WHI)近年研究结果证实激素替代治疗(HRT)在预防和治疗绝经后骨质疏松症(postmenopausal osteoporosis,PMOP)中的作用,随机对照实验数据表明,HRT可以增加骨皮质和骨小梁的骨密度(bone mineral density,BMD)以及全身骨矿含量(bone mineral content,BMC),并存在剂量相关性.各项观察数据证实HRT在降低脊椎及股骨骨折上有积极影响,但HRT的副反应限制其在预防治疗骨质疏松症中的应用.
-
An Inhomogeneous and Anisotropic Constitutive Model of Human Dentin
Introduetion In human dentin,microscopic tubules extend through the entire dentin with variational diameters.The peritubular dentin encircles the tubules and is characterized by its high mineral content.The intertubular dentin occupies the volume outside of peritubular dentin and contains more collagen and less mineral than the peritubular dentin.The above structural characters of dentin should lead to an inhomogeneous and anisotropic stress-strain relation of dentin.In the past years,a lot of experiments based on the microscopic structure of dentin had been done.Some attempts on theoreticallv modeling constitutive law of dentin were also presented.Here author gives an inhomogeneous and anisotropic constitutive model of human dentin,considering the difference of peri-and intertubular dentin,and compare the FEA results basing on this model with the moiréfringe testing results of Wang and Weiner(1998).
-
促性腺激素释放激素类似物治疗87例特发性中枢性性早熟女孩的长期观察:对成年身高、体重指数、骨矿质含量和生育功能的影响
促性腺激素释放激素类似物(GnRHa)用于治疗中枢性性早熟(CPP)已有20余年.尽管迄今已有相当数量的CPP患者经GnRHa多年治疗后已达到成年身高(AH),但对于治疗能否改善成年身高仍有争论.本文是一个单中心回顾性研究,87例特发性中枢性性早熟(ICPP)女孩接受了GnRHa治疗并在停药后观察了数年,根据所得资料就该药对成年身高、体重指数(BMI)、骨矿质密度(BMD)和生育功能的影响进行了评估.
-
我国人群峰值骨量及其影响因素的研究进展
峰值骨量是指正常生理条件下骨成熟期的大骨量(bone mineral content BMC),在峰值骨量期骨骼的强度大.峰值骨量的确定是诊断骨质疏松症的前提,目前WHO确定的一个地区的骨质疏松症诊断即以峰值骨量减少2.5SD为诊断标准的.我国幅员辽阔,由于地理位置、经济状况、人口分布、生活方式等因素的影响,各地区峰值骨量不尽相同.运动、营养、生活方式等环境因素对于峰值骨量的高低有一定影响,研究这些影响因素对防治骨质疏松亦有重要意义.现将近10年来我国有关地区峰值骨量的测定结果及环境因素对其影响的研究概况综述如下.
-
骨质疏松诊断及骨矿含量测定方法
1 骨质疏松的诊断骨质疏松(osteoporosis)的诊断一直为学者们所关注,鉴于目前生化检查尚不能作为诊断指标,故骨矿含量(bone mineral content,BMC)测定或骨密度(bone mineral density,BMD)测定已成为目前诊断骨质疏松的重要手段.