透明质酸/壳聚糖复合支架的制备及其力学性能评价

目的　模拟天然骨组织的结构和成分,寻找适合骨组织工程的新型支架材料。 方法 以透明质酸、壳聚糖为基质材料,在微酸性环境中以一定配比与氯化钙和磷酸二氢钠混合,冷冻干燥得到多孔复合支架材料。然后在乙醇/水/尿素环境中分别陈化0、2、4、8、12和24 h,以生成产物钙磷盐前驱体转变为羟基磷灰石,最终制备出一种深度矿化的透明质酸/壳聚糖复合支架。并通过SEM、EDS等对支架进行表征,研究支架的形貌、成分及力学强度等性能。 结果 SEM观察显示,支架材料具有比较均匀的多孔结构,孔径大小为100~200 μm。EDS结果表明,复合支架在一次冻干之后形成的是磷酸氢钙（DCPD）,随着陈化时间的延长,DCPD逐渐向羟基磷灰石（HAP）转化。而压缩强度则表明经过原位矿化的支架力学性能显著提高。 结论 通过该法得到的透明质酸/壳聚糖复合支架可作为骨组织工程的新型支架材料。     

Relationship between chronological and bone ages and pubertal stage of breasts with bone biomarkers and bone mineral density in adolescents

ObjectiveTo study bone mineral density (BMD) in adolescent females according to five groups of chronological age (CA), bone age (BA), and breast development stage (B), and to correlate these parameters with plasma bone biomarkers (BB).MethodsThis was a cross-sectional study performed in 101 healthy adolescent females between 10 and 20 years old. The study variables were: weight, height, body mass index (BMI), CA, B, BA, calcium intake, BMD, and BB. Osteocalcin (OC), bone alkaline phosphatase (BAP), and C-terminal telopeptide (S-CTx) were evaluated for BB. BMD was measured using dual energy X-ray absorptiometry (DXA).ResultsBMD in lumbar spine, proximal femur, and total body increased with age, and the respective observed averages were: in CA1 (10 years old), 0.631, 0.692, 0.798 g/cm²; in CA2 (11 to 12 years old), 0.698, 0.763, 0.840 g/cm²; in CA3 (13 to 14 years old), 0.865, 0.889, 0.972 g/cm²; in CA4 (15 to 16 years old), 0.902, 0.922, 1.013 g/cm²; and in CA5 (17 to 19 years old), 0.944, 0.929, 1.35 g/cm². These results showed significant differences between 13 and 14 years of age (CA3) or when girls reached the B3 stage (0.709, 0.832, 0.867 g/cm²). The highest median concentrations of BB were between 10 and 12 years of age when adolescents were in the B2–B3 (p < 0.001). Median BB concentrations decreased in advanced BA and B.ConclusionsBB concentrations were positively correlated with the peak height velocity and negatively correlated with BMD in the study sites. Increased BMD and BB concentrations were observed in B3.     

被动吸烟对鼠牙槽骨钙、磷含量及碱性磷酸酶活性的影响

目的 分析被动吸烟鼠牙槽骨钙、磷含量和碱性磷酸酶（AKP）的活性。方法 40只6周龄健康雄性Wistar鼠被随机等量分为实验组和对照组,每组再被随机等量分为15、30、45和60 d 4个亚组,烟熏法建立被动吸烟的大鼠模型,浓酸消化法提取牙槽骨内钙和磷,光谱分析法和改良Reddi法分别测定钙、磷含量和AKP的活性,行析因设计的方差分析。结果 与各对照组牙槽骨相比,被动吸烟鼠的钙、磷含量在15 d组略有升高,30 d组略有下降,差异无统计学意义（P〉0.05）,45、60 d组显著下降（P〈0.01）;AKP活性在15、30 d组略升高,45、60 d组略下降,差异无统计学意义（P〉0.05）。结论 本实验周期内,鼠牙槽骨钙、磷含量和AKP活性在被动吸烟初期略有升高,随被动吸烟时间的延长,钙、磷含量呈时间依赖性减少,AKP活性也呈时间依赖性减少的趋势。     

表皮生长因子受体在人牙周膜成纤维细胞体外矿化中的作用

目的 探讨表皮生长因子受体（EGFR）在人牙周膜成纤维细胞（hPDLC）体外矿化中的作用。方法 体外培养hPDLC,运用免疫细胞化学技术,对hPDLC体外矿化前后EGFR的表达进行比较研究;应用原位杂交及RT-PCR技术,对矿化前后的hPDLC mRNA进行检测。结果 诱导前EGFR呈高表达,随着地塞米松诱导时间的延长,其表达逐渐下降,在矿化结节形成后的第4周,几乎呈阴性表达,与成骨细胞中EGFR的表达一致。原位杂交中杂交信号与免疫细胞化学的检测结果基本一致,RT-PCR的mRNA半定量检测发现,随着hPDLC的体外矿化,碱性磷酸酶升高,EGFR表达降低。结论 EGFR在hPDLC的矿化过程中起着负调控作用,与牙周膜自身结构的稳定性有关。     

Hazards of Radioactive Mineralization Associated with Pegmatites Used as Decorative and Building Material

The present study aimed to assess the radiological hazards associated with applying the investigated granite in the building materials and the infrastructures applications. The investigated granites are classified into four categories: El-Urf, barren, colourful and opaque. El Urf monzogranite intrudes metagabbro diorite complex with sharp contacts. Based on the activity concentrations, the environmental parameters such as absorbed dose rate (D_air), annual effective dose (AED), radium equivalent activity (Ra_eq), external (H_ex) and internal (H_in) hazard indices were measured. The mineralized pegmatite is located in the southwestern foothill of the Gabal El Urf younger granite. It displays well-defined zonation of three zones: outer, middle and inner zones represented by potash feldspar, quartz and mica, respectively. The isorad map showed that El Urf monzogranite is barren (Up to 100 cps) surrounding an excavation of the studied pegmatite that exhibits moderate colorful mineralization (phase-I = 500–1500 cps) and anomalous opaque mineralization (phase-II = 1500–3500 cps) pegmatites. The obtained results of radionuclides activity concentrations illustrated that the Opaque granites have the highest values of ²³⁸U (561 ± 127 Bq kg⁻¹), ²³²Th (4289 ± 891 Bq kg⁻¹) and ⁴⁰K (3002 ± 446 Bq kg⁻¹) in the granites, which are higher than the recommended worldwide average. Many of the radiological hazard parameters were lesser than the international limits in the younger granites and barren pegmatites. All of these parameters were higher in the colorful and opaque mineralized pegmatites. The high activity and the elevated radiological hazard parameters in the mineralized pegmatites are revised to the presence of radioactive and radioelements bearing minerals, such as thorite, meta-autunite, kasolite, phurcalite, columbite, fergusonite, Xenotime and fluorapatite. Other instances of mineralization were also recorded as cassiterite, atacamite, galena, pyrite and iron oxide minerals. Thus, the granites with high radioactivity concentration cannot be applied in the different applications of building materials and ornamental stones.     

LIM矿化蛋白1在大鼠牙髓损伤修复中的时空表达

目的:探讨LIM矿化蛋白1(LIM mineralization protein 1,LMP-1)在大鼠磨牙牙髓损伤修复中的表达.方法:建立大鼠磨牙牙髓损伤修复动物模型,用免疫组织化学染色方法观察LMP-1在大鼠牙髓损伤修复中的表达,并用Image-Pro Plus 6.0图像分析软件及单因素方差分析比较各组间的差异.结果:在正常大鼠牙髓组织中LMP-1表达阴性;在大鼠牙髓损伤后1d,LMP-1表达于成牙本质细胞及部分牙髓成纤维细胞;术后3 d,LMP-1表达于坏死牙髓下方的细胞增殖层;术后7d,LMP-1显著表达于增殖活跃的牙髓细胞及部分成牙本质细胞中.结论:LMP-1在牙髓损伤修复过程中呈时空特异性表达,可能参与成牙本质细胞及牙髓细胞的增殖、分化及修复性牙本质的形成.     

Multipotent adult progenitor cell‐loaded demineralized bone matrix for bone tissue engineering

Multipotent adult progenitor cells (MAPCs) from bone marrow have been shown to be capable of forming bone, cartilage and other connective tissues. In addition, MAPCs differentiate into lineages that are different from their germ layers of origin. Previous studies showed the ability of MAPCs to improve cardiac function and control allogenic‐reactive responses associated with acute graft versus host disease. In the current study, we evaluated the ability of MAPCs to produce bone matrix on demineralized bone allograft substrates. Specifically, MAPCs expressed alkaline phosphatase, produced extracellular matrix proteins and deposited calcium‐containing mineral on demineralized bone matrices. Furthermore, the addition of MAPCs on demineralized bone matrix (DBM) scaffolds enhanced osteoinductivity of the carrier in a rat ectopic pouch model. These results demonstrated the potential of MAPCs as a new approach for bone repair in tissue‐engineering applications. Copyright © 2013 John Wiley & Sons, Ltd.     

Changes in bone mineralization,architecture and mechanical properties due to long-term (1 year) administration of pamidronate (APD) to adult dogs

The goal of this study was to evaluate the effect of 1 year of APD administration on bone mineralization and bone mineral chemistry in the dog. Disodium pamidronate (APD) was given orally by gavage to mature beagle dogs at doses of 0, 2.5, 12.5 and 25.0 mg/kg per day (0.1% concentration for 12 months) as part of a long-term toxicity study. The os ilium and a vertebra were used to determine the mineralization profile and, subsequently, each density fraction was analysed chemically. Theribs were used to determine lattice parameters of the apatite crystal size using X-ray diffraction. The sternum was used to determine selected morphometric parameters using image analysis of specimen X-ray films and subsequently to determine mechanical properties using velocity-of-sound techniques. We found that for both the ilium and the vertebrae there was a significant shift of the mineralization profile towards greater density in a dose-related manner. This effect levelled off with the highest dose because the shift in mineralization profile correlated better with the square root of the dose than with the dose. Together with data on crystal size, which show an increase in lattice parameters and a decrease in crystal size with dose, our data lead us to believe that long-term administration of APD leads to an increase in bone mineralization without major changes in bone chemistry of Ca, Mg, and P and with a decrease in bone apatite crystal size. The image analysis shows a dose-related increase in trabecular bone volume and thickness. Furthermore, the elastic modulus of the trabecular bone increased linearly with the square root of the administered dose. These findings suggest that APD treatment increases the packing density of bone crystals and may decrease the solubility of bone mineral.     

Post‐Traumatic Heterotopic Ossification: An Old Problem in Need of New Solutions

Heterotopic ossification (HO) is the formation of pathological bone in ectopic sites and it can have serious consequences for functional outcomes. For many years, its main clinical relevance was as a rare complication of elective joint arthroplasty or CNS injury and a number of prophylaxes were developed to mitigate against it in these settings. As a consequence of changes in patterns of wounding and survival in conflicts since the turn of the century, post‐traumatic HO has become much more common and case severity has increased. It represents one of the main barriers to rehabilitation in a large cohort of combat‐injured patients. However, extant prophylaxes have not been shown to be effective or appropriate in this patient cohort. In addition, the lack of reliable early detection or means of predicting which patients will develop HO is another barrier to effective prevention. This review examines the current state of understanding of post‐traumatic HO including the historical context, epidemiology, pathophysiology, clinical issues, currently prophylaxis and detection, management, and potential future approaches. Our aims are to highlight the current lack of effective means of early detection and prevention of HO after major trauma and to stimulate research into novel solutions to this challenging problem. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1061–1068, 2018.