万古霉素壳聚糖微球-大孔磷酸钙骨水泥支架的体外释放实验

目的构建具有缓释药物效能的大孔磷酸钙骨水泥(CPC)支架,并检测其药物缓释能力和对材料力学的变化。方法以乳化化学交联法制备万古霉素壳聚糖(CS)载药微球并测定药物包封率;CPC与不同质量载药微球(2 mg、6 mg、10 mg)混合制备CS-大孔CPC支架,测定载药微球-CPC的药物缓释曲线,并选择初始与8、72、168、216 h共5个时间点比较药物释放浓度。万能试验机检测载药CS-CPC支架的弹性模量变化。药物释放浓度比较和弹性模量采用单因素方差分析进行比较。结果 CS微球对万古霉素包封率约为30.6%;加入不同量的CS微球对弹性模量无明显改变,差异无统计学意义(P0.05)。2 mg、6 mg、10 mg的CS微球与大孔CPC复合后,均能缓慢稳定释放药物。初始、8 h、72 h、168 h时间点比较药物释放浓度,三组的浓度差异有统计学意义(F=234.91,7171.27,1161569,60.5;P0.05),其中6 mg组与2 mg和10 mg组的差异有统计学意义(P0.05);到216 h时,各组药物浓度差异均无统计学意义(P0.05)。结论万古霉素CS微球复合大孔CPC支架具有较为理想的药物缓释效果,并对支架的力学性能影响不大,是一种可选择的治疗骨缺损伴感染的载药材料。     

阿仑膦酸钠/磷酸钙骨水泥释放体系结构及体外释放规律的研究

目的 制备不同浓度的阿仑膦酸钠/磷酸钙骨水泥释放体系,观察阿仑膦酸钠对磷酸钙骨水泥结构的影响及复合释放体系体外释放的规律.方法 分别制备1wt％、3wt％和5wt％的载阿仑膦酸钠磷酸钙骨水泥释放体系,分别采用傅氏转换红外线光谱分析仪、扫描电子显微镜和高效液相色谱仪研究载阿仑膦酸钠磷酸钙骨水泥的结构和药物体外释放规律.结果 阿仑膦酸钠的载入没有改变磷酸钙骨水泥相成分的官能团;扫描电镜下各实验组微观结构相似,均呈珊瑚样状结晶体相互交织成网状结构;各组药物在同一时间点释放量(％)的差异无统计学意义(P＞0.05),各组药物的释放均分为48 h前的突释阶段和48 h后的缓释阶段,符合Higuchi机制扩散释放模型.结论 阿仑膦酸钠的载入对磷酸钙骨水泥的晶体结构基本没有影响,且在磷酸钙骨水泥释放体系中能够持续、稳定的释放.     

薄荷油的胶束增溶体系的释放规律

对于胶束增溶体系来讲,被增溶物从增溶溶液到空气相中的释放情况即释放规律是该体系的一个重要研究内容.作者采用顶空气相色谱法对薄荷油的胶束增溶体系进行了释放研究.选用了一系列质量浓度梯度的Tw80溶液,探讨了薄荷油的释放性与Tw80质量浓度之间的关系.     

尼尔雌醇皮埋剂的研制及体内外释放实验

目的　研制尼尔雌醇皮埋剂,了解其体内、体外释药行为,为长期雌激素替代治疗防治绝经后骨质疏松提供一种新的选择。方法　首先制成尼尔雌醇皮埋剂;接着建立其体外药物释放体系及药物体外释放量的反相高效液相色谱(RP-HPLC)的检测方法;同时将尼尔雌醇皮埋剂植入SD大鼠体内,于植入后4、5、8个月取出,用剩余药量推算体内释药量;最后对体内、外累积释放量(Q)与时间(t)进行线性回归分析并绘制尼尔雌醇皮埋剂体外释放曲线和体内、外Q-t曲线。　结果　尼尔雌醇皮埋剂体外释放最初1周释放量较大,之后平稳释放,Q和t线性相关良好(r=0.996,P=0.000),平均体外释放量为33.0566μg/日*支;体内释放实验中Q和t也呈良好的线性相关(r=0.985,P=0.015),平均体内释放量为19.65μg/日*支。结论　(1)尼尔雌醇皮埋剂体外释放在最初1周存在爆破效应,之后符合零级动力学释放;其在体内释放也符合零级动力学释放,尼尔雌醇皮埋剂有可能达到长效控释的目的。(2)NYL皮埋剂周期性或持续性加用孕激素可能成为长期雌激素替代治疗防治绝经后骨质疏松的一种新的选择。     

RBX-庆大霉素药物释放系统的研制及体外释放实验

目的 :研制复合bBMP的异种骨庆大霉素局部药物释放系统 ,为治疗开放性骨折提供简便有效方法。材料和方法 :以复合bBMP的异种骨为核心载体 ,采用明胶包裹法和聚已内酯 (Poly ε caprolacton ,PCL)多重包裹法制成复合庆大霉素的植骨材料 ,对其进行表面结构和体外释放实验研究。结果 :2种方法制成的植骨材料均在 2 4h内有一爆发释放 ,并能维持一定时间的缓慢释放。其中PCL多重包裹法制成的RBX -G -LDDS在 2 5d时仍能达到 4.38ug/ml的释放浓度 ,高于庆大霉素对金黄色葡萄球菌的MIC(2ug/ml)。结论 :RBX -G -DDS具有良好的体外缓释特性 ,结合RBX的诱导成骨作用 ,能提供一种治疗开放性骨折的新方法     

丙泊酚对脊髓星形胶质细胞释放兴奋性氨基酸的影响

目的　研究被肿瘤坏死因子α(TNF α)刺激的大鼠脊髓星形胶质细胞(AST)在丙泊酚 作用下兴奋性氨基酸(EAA)的释放情况。方法　体外纯化培养大鼠脊髓AST,分为TNF α终浓度 为1μg/L及丙泊酚终浓度为25μmol/L组(TP组),TNF α终浓度为1μg/L组(T组),乳剂对照组 (intralipid,0.2ml/L,L组),空白对照组(C组)。用高效液相色谱仪测定各组培养细胞在0、30、60、 120min时谷氨酸(Glu)、天门冬氨酸(Asp)的释放量。结果　与C组相比,L组的Glu、Asp释放量无 显著性差异(P>0.05);T、TP组Glu、Asp释放量随着时间的延长而增加;与T组相比,60、120min 时,TP组Glu、Asp释放量明显减少(P<0.05)。结论　TNF α刺激AST释放EAA,而丙泊酚对此 有抑制作用。     

几丁糖庆大霉素药物释放系统的研究

目的　研究几丁糖庆大霉素药物释放系统释放行为及临床应用疗效。　方法　以 3 0只家兔为实验对象 ,采用体外、体内释放实验评价几丁糖庆大霉素缓释药缓释效果 ;临床上采用几丁糖庆大霉素缓释药治疗慢性骨髓炎 18例 ,以术后切口愈合情况、临床表现和X线表现评定疗效。　结果　体外释放实验显示第 1天释放量为 92 6 7μg/颗 ,其后下降并以 4 0 μg·颗 -1·d-1较低水平稳定释放 ,达 2 5天以上 ;体内释放实验显示血药浓度峰值 ( 0 92 μg/ml)在 2 4h出现 ;术后血尿素氮 (BUN)和肌酐 (Cr)值无增加 ;术后第 8周 ,药棒周围骨组织中庆大霉素浓度仍在骨髓炎常见致病菌最小抑菌浓度 (MIC)以上。临床应用 18例患者均获随访 ,随访时间 6～ 3 4个月 ,平均 2 4 8个月。初期愈合率88 9% ( 16/ 18) ,无复发。　结论　几丁糖庆大霉素缓释药具有较好体内外缓释作用 ,临床上对于治疗骨感染有应用前景。     

钛合金表面利福平复合凝胶涂层的药物释放动力学研究

[目的]为减少晚期关节结核人工关节置换术后复发风险,探索钛合金材料表面利福平缓释涂层的可行性,并研究其体内外药物释放特性。[方法]通过迈克尔加成反应在钛合金(titanium alloy,Ti alloy)材料表面形成聚多巴胺(poly dopamine,PDA)薄膜;将利福平(rifampicin,RFP)粉剂加载入交联淀粉(crosslinked starches,CS)及四臂巯基聚乙二醇(polyethylene glycol,PEG)中构建水凝胶,通过浸渍-提拉法涂覆于PDA薄膜表面,制成TiPDA-PEG-CS-RFP(Ti-PPCR)涂层。用高效液相色谱法(HPLC)检测Ti-PPCR在模拟体液中药物释放特点;将载药量为6.2 mg的Ti-PPCR钛合金片置入20只新西兰大白兔右侧股骨髁内,分别于术后5、10、15、20 d处死取材,应用HPLC检测术后实验材料周围骨组织、肌肉组织和兔静脉血中RFP释放浓度。[结果]Ti-PPCR在模拟体液中RFP在前3 d释放速率较快,累积释放量占总药量的63.2%,随后释放趋于平缓,总释放率为79.2%,总释放时间达9 d。体内骨组织和肌肉组织中药物浓度迅速上升,到第5 d都达到最高峰,随后平缓降低,总释放周期分别可长达20 d和10 d,且都在最小杀菌浓度以上,静脉血液中未测到利福平。[结论]钛合金表面构建的Ti-PPCR利福平缓释涂层,有一定的利福平局部缓释能力。     

磷酸钙骨水泥复合去甲万古霉素后理化性质改变及药物释放规律的研究

目的研究磷酸钙骨水泥(calcium phosphate cement，CPC)复合抗生素后理化性质的改变及体外药物释放规律。方法将CPC中复合1％、3％、50h，的去甲万古霉素，观察水泥的固化时间，测试固化强度，通过X线衍射(XRD)及傅立叶变换红外光谱分析(FTIR)检测固化产物，将抗生素骨水泥浸泡于生理盐水中，定期取浸泡液，用紫外分光光度计测定抗生素浓度，观察抗生素释放特点。结果随着加入去甲万古霉素浓度的增加，骨水泥固化时间缩短，固化强度降低，含量为5％时，抗压强度最低为20．1MPa，但仍高于正常松质骨强度。XRD与FTIR显示固化产物仍为碳酸化羟基磷灰石(carbonated hydroxyapatite，CHA)。抗生素在初期释放很快，48h后释放速度减慢并长时间维持。结论CPC具有原位固化特性，固化反应温和，不产生高热，不影响药物活性，体外实验证明可以维持很长的药物释放时间，是一种理想的抗生素载体，用于骨髓炎的治疗。     

胰岛素释放试验异常对PCOS患者IVF/ICSI结局的预测作用

目的探讨胰岛素释放试验异常对多囊卵巢综合征(PCOS)患者体外受精/卵胞浆内单精子注射-胚胎移植(IVF/ICSI-ET)妊娠结局的预测作用。方法选取就诊于青岛市妇女儿童医院生殖中心行助孕治疗的PCOS患者119例,所有入组的PCOS患者均行口服葡萄糖耐量试验(OGTT)及胰岛素释放试验。根据胰岛素释放试验将PCOS患者分为两组,胰岛素释放试验正常组50例(空腹胰岛素为3.0~25.0mU/L,2h胰岛素低于1h胰岛素,血胰岛素200mU/L),胰岛素释放试验异常组69例。比较2组患者临床结局。结果胰岛素释放试验正常组双原核(2PN)数、优质胚胎数及鲜胚移植时生化妊娠率、胚胎种植率、临床妊娠率明显高于胰岛素释放试验异常组,差异有统计学意义(P0.05)。胰岛素释放试验正常组患者获卵数、成熟卵数有高于胰岛素释放试验异常组的趋势,胰岛素释放试验正常组患者早期流产率有低于胰岛素释放试验异常组的趋势,但差异均无统计学意义(P0.05)。结论胰岛素释放试验可以作为预测PCOS患者IVF/ICSI-ET妊娠结局的良好指标。胰岛素释放试验异常对PCOS患者IVF/ICSI-ET妊娠结局造成不利影响,对于此类患者在进行助孕治疗前最好给予预处理以改善其妊娠结局。     

Anisotropic properties of human tibial cortical bone as measured by nanoindentation.

The purpose of this study was to investigate the effects of elastic anisotropy on nanoindentation measurements in human tibial cortical bone. Nanoindentation was conducted in 12 different directions in three principal planes for both osteonic and interstitial lamellae. The experimental indentation modulus was found to vary with indentation direction and showed obvious anisotropy (one-way analysis of variance test, P < 0.0001). Because experimental indentation modulus in a specific direction is determined by all of the elastic constants of cortical bone, a complex theoretical model is required to analyze the experimental results. A recently developed analysis of indentation for the properties of anisotropic materials was used to quantitatively predict indentation modulus by using the stiffness matrix of human tibial cortical bone, which was obtained from previous ultrasound studies. After allowing for the effects of specimen preparation (dehydrated specimens in nanoindentation tests vs. moist specimens in ultrasound tests) and the structural properties of bone (different microcomponents with different mechanical properties), there were no statistically significant differences between the corrected experimental indentation modulus (Mexp) values and corresponding predicted indentation modulus (Mpre) values (two-tailed unpaired t-test, P > 0.5). The variation of Mpre values was found to exhibit the same trends as the corrected Mexp data. These results show that the effects of anisotropy on nanoindentation measurements can be quantitatively evaluated.     

Cartilage mechanics in the guinea pig model of osteoarthritis studied with an osmotic loading method

OBJECTIVE: To determine the material properties of articular cartilage in the Hartley guinea pig model of spontaneous osteoarthritis. METHODS: Cartilage-bone samples from the medial femoral condyle and tibial plateau of 12 month-old guinea pig knees were subjected to osmotic loading. Site-matched swelling strains and fixed charge density values were used in a triphasic theoretical model for cartilage swelling to determine the modulus of the cartilage solid matrix. The degree of cartilage degeneration was assessed in adjacent tissue sections using a semi-quantitative histological grading scheme. RESULTS: Decreased values for both moduli and surface zone fixed charge density were associated with increasing grades of cartilage degeneration. Decreases in moduli reflect damage to the collagen matrix, which give rise to greater swelling strains. CONCLUSION: Histological evidence of cartilage degeneration was associated with impaired cartilage mechanics in the aging Hartley guinea pig.     

Altered swelling behavior of femoral cartilage following joint immobilization in a canine model.

Periods of reduced joint loading have been shown to induce changes in the biochemical composition. metabolism and mechanics of articular cartilage. In this study, changes in cartilage swelling behavior were studied following a 4-week period of joint immobilization, using a recently developed osmotic loading technique [J. Biomech, 32 (1999) 401-408]. The magnitude and distribution of swelling strains were measured in cartilage-bone samples equilibrated in physiological and hypotonic saline, relative to a hypertonic reference NaCl solution. Physicochemical parameters (glycosaminoglycan fixed charge density and water volume fraction) were determined in site-matched cartilage samples. The experimental data for swelling strains, fixed charge density and water volume fraction were used with a triphasic mechano-chemical theory [J. Biomech. Eng. 113 (1991) 245-258] to determine the effect of joint immobilization on the tensile modulus of the cartilage solid matrix. Four weeks of immobilization resulted in a significant increase in the magnitude of swelling-induced strains, and a significant decrease in fixed charge density in cartilage, as compared with the contralateral controls. Joint immobilization also resulted in decreases in values for the modulus of cartilage, as compared with the contralateral controls. Our results suggest that 4 weeks of joint immobilization had a significant effect on cartilage mechanical function that may be linked to collagen changes in the cartilage extracellular matrix.     

射频能量在治疗关节软骨退变中对软骨细胞及基质的影响

[目的]实验研究射频消融能量大小与关节软骨细胞及基质损伤效应之间的关系.[方法]建立牛膝关节软骨退变模型,模拟膝关节镜环境,射频消融气化仪在15、40、70 W的不同能量设置条件下,处理牛膝关节退变软骨1 min,同时设置对照组,共分4组,每组6份标本,随后行软骨组织块培养,HE染色,FDA/PI双荧光染色,GAG释出率.[结果]随着射频消融能量的增加,空泡率明显增加,软骨细胞死亡率明显增加,GAG释出率明显减少.[结论]随着射频消融输出能量的增加,软骨细胞死亡率明显增加,软骨基质损伤明显加重,射频消融能量大小与关节软骨细胞及基质的损伤呈正相关关系.     

蛇床子素对绝经后骨质疏松症大鼠骨代谢的调节作用及机制

目的 探究蛇床子素对绝经后骨质疏松症(postmenopausal osteoporosis,PMO)模型大鼠骨代谢生化指标及磷脂酰肌醇3-激酶/蛋白激酶B(PI3K/AKT)通路的影响.方法 选取90只雌性大鼠,采用随机数字表法将大鼠分为:健康对照组、模型组、雌二醇组和蛇床子素低、中、高剂量组,每组15只.除健康对照...     

鼻部软骨弹性模量的测定

目的测量鼻部主要软骨的弹性模量数据,包括大翼软骨、侧鼻软骨和鼻中隔软骨,为运用有限元方法分析鼻畸形的形成提供数据基础。方法采集10例成人尸体鼻部软骨组织,包括大翼软骨、侧鼻软骨和鼻中隔软骨。分别测量鼻部软骨标本的压缩和拉伸状态下的应力-应变曲线,通过软件进行数据分析。结果对成人尸体鼻部各软骨的应力-应变曲线进行分析,通过最小二乘法拟合获得每个样本的弹性模量值。大翼软骨、侧鼻软骨和中隔软骨的压缩弹性模量统计值为(1.142±0.336)MPa、(5.84±1.246)MPa和(5±1.685)MPa;大翼软骨、侧鼻软骨和中隔软骨拉伸弹性模量统计值为(4.679±1.641)MPa、(8.601±2.131)MPa和(6.907±1.621)MPa。结论拉伸弹性模量普遍大于压缩弹性模量;侧鼻软骨弹性模量>中隔软骨弹性模量>大翼软骨弹性模量;相对于人体其他荷重软骨和骨性结构,鼻部主要软骨的弹性模量值较小。     

Age, gender, and bone lamellae elastic moduli.

To enhance preventative and therapeutic strategies for metabolic bone diseases and bone fragility disorders, we began to explore the physical properties of bone tissue at the cellular level. Proximal femurs were harvested from 27 cadavera (16 male and 11 female) for in vitro measurement of the mechanical properties. We measured the variations in lamellar-level elastic modulus and hardness in human bone as a function of age and gender to identify microstructural properties responsible for age and gender-related reductions in the mechanical integrity. The lateral femoral necks were examined, and age, gender, height, body mass, and body mass index were not found to correlate with lamellar-level elastic modulus or hardness. This result was consistent for osteonal, interstitial, and trabecular tissue. These data suggest that increased bone mass maintenance, known to occur in heavier individuals, is not accompanied by increases in the lamellar-level elastic modulus or hardness. The independence of elastic modulus and hardness from age and gender suggests that age and gender-related decreases in mechanical integrity do not involve alterations in elastic modulus or hardness of the extracellular matrix. Lamellar-level ultimate, fatigue, and fracture toughness properties should also be investigated. Other factors, such as tissue mass and organization, may also contribute to age and gender-related decreases in the mechanical integrity.     

Lactation‐Induced Changes in the Volume of Osteocyte Lacunar‐Canalicular Space Alter Mechanical Properties in Cortical Bone Tissue

Osteocytes can remove and remodel small amounts of their surrounding bone matrix through osteocytic osteolysis, which results in increased volume occupied by lacunar and canalicular space (LCS). It is well established that cortical bone stiffness and strength are strongly and inversely correlated with vascular porosity, but whether changes in LCS volume caused by osteocytic osteolysis are large enough to affect bone mechanical properties is not known. In the current studies we tested the hypotheses that (1) lactation and postlactation recovery in mice alter the elastic modulus of bone tissue, and (2) such local changes in mechanical properties are related predominantly to alterations in lacunar and canalicular volume rather than bone matrix composition. Mechanical testing was performed using microindentation to measure modulus in regions containing solely osteocytes and no vascular porosity. Lactation caused a significant (～13%) reduction in bone tissue‐level elastic modulus (p < 0.001). After 1 week postweaning (recovery), bone modulus levels returned to control levels and did not change further after 4 weeks of recovery. LCS porosity tracked inversely with changes in cortical bone modulus. Lacunar and canalicular void space increased 7% and 15% with lactation, respectively (p < 0.05), then returned to control levels at 1 week after weaning. Neither bone mineralization (assessed by high‐resolution backscattered scanning electron microscopy) nor mineral/matrix ratio or crystallinity (assessed by Raman microspectroscopy) changed with lactation. Thus, changes in bone mechanical properties induced by lactation and recovery appear to depend predominantly on changes in osteocyte LCS dimensions. Moreover, this study demonstrates that tissue‐level cortical bone mechanical properties are rapidly and reversibly modulated by osteocytes in response to physiological challenge. These data point to a hitherto unappreciated role for osteocytes in modulating and maintaining local bone mechanical properties. © 2016 American Society for Bone and Mineral Research.     

Influence of mechanical behavior on the wear of 4 clinically relevant polymeric biomaterials in a hip simulator

The elastic and large-deformation mechanical behavior of 4 materials with known clinical performance was examined and correlated with the wear behavior in a hip simulator. Acetabular liners of a commercially available design were machined from ultra-high molecular weight polyethylene (UHMWPE), high-density polyethylene (HDPE), polytetrafluoroethylene (PTFE), and polyacetal and wear tested in a multidirectional hip joint simulator. Elastic and large-deformation mechanical behavior was directly measured from the wear-tested liners using the small punch test. The finite element method was used to compute elastic modulus from the measured small punch test initial stiffness, and the contact stress for the liners was calculated using the theory of elasticity solution. Positive, statistically significant correlations were observed between the hip simulator wear rate and the initial peak load, ultimate load, and work to failure from the small punch test. Negative correlations were observed between the wear rate and the elastic modulus and contact stress. The results of this study support the hypothesis that the large-deformation mechanical behavior of a polymer plays a greater role in the wear mechanisms prevalent in total hip replacements than the elastic behavior.     

软骨细胞外基质与壳聚糖复合制备组织工程软骨支架及其性能研究

 目的 探讨采用壳聚糖与脱细胞软骨基质复合制备组织工程软骨支架的可行性,检测其理化性能和细胞相容性。方法 取天然人软骨粉碎.取 100 nm~5μm 软骨微丝,脱细胞处理后制备为质量浓度 1%悬液.与质量浓度 2%壳聚糖醋酸溶液按 1颐1(重量比)充分搅拌混合,冷冻干燥制备复合支架。对支架交联,并进行组织学、扫描电镜、孔隙率及吸水性测定、生物力学评估, MTT法分析支架浸提液毒性。分离培养犬软骨细胞.种植到支架上.倒置显微镜、电镜观察细胞在支架的生长、分化情况。结果 组织学显示支架中无细胞碎片残留.II型胶原免疫组化染色阳性。扫描电镜显示支架内孔洞相互连通似海绵状.孔径为(136.2±34.9)μm.孔隙率为 81.4%±3.5%.吸水性约为 1525.7±129.3%。支架纵向弹性模量为(1.940±0.335)MPa。 MTT法显示不同浓度支架浸提液与对照培养液吸光度值比较.差异无统计学意义(P>0.05)。倒置显微镜观察.细胞在支架上粘附良好.扫描电镜下细胞在支架上均匀分布.呈圆形或椭圆形.有基质分泌。结论 软骨细胞外基质和壳聚糖复合制备的仿生三维多孔双相支架.具有较高的孔隙率和吸水性.良好的生物力学特性.无毒.生物相容性良好.是组织工程软骨的良好支架载体。