Organic interlamellar layers,mesolayers and mineral nanobridges: Contribution to strength in abalone (Haliotis rufescence) nacre

The contributions of mesolayers, organic interlamellar layers and nanoasperities/mineral bridges to the strength of nacre from red abalone (Haliotis rufescens) shell nacre are investigated. Samples were demineralized and deproteinized to separate the organic and mineral components, respectively. Tensile tests were performed on both the isolated organic constituent and the isolated mineral. The strength of the isolated organic component suggests that growth bands play an important role in the mechanical behavior as they are thick regions of protein that are a significant fraction (∼0.4) of the total organic content. The thickness variation of the nacre tablets was measured and found to be a small fraction of the mean tablet thickness (0.568 μm); the standard deviation is 26 nm, indicating that the wedge mechanism of toughening does not operate in the nacre investigated. Results obtained from the isolated mineral validate the importance of the organic constituent as the mechanical properties decline greatly when the organic component is removed. The results presented herein add to the understanding of the mechanical response of the organic interlayers and growth bands and their effect on the toughness of the abalone nacre.     

An electron microscope study of the formation of the nacreous layer in the shell of certain bivalve molluscs

An electron-microscopic study was made of nacreous shell growth in several species of marine molluscs. Studies of sections of mantle-shell preparations show that the first step in crystal formation is the polymerization of part of the pallial fluid to form lamellae parallel to the surface of the epithelium. These lamellae form compartments enclosing a modified apallial fluid. Initiation of crystals occurs in these compartments in contact with a crystal in an adjacent layer. During crystal growth the organic matrix present in the compartment is displaced by the growing surface of the crystal. When growth is complete the crystal is entirely enveloped by a delicate organic sheath. These studies show that the pallial fluid with its organic constituents is responsible for supplying a matrix or substrate for crystal initiation and growth. It serves as a regulatory device for guiding the orderly growth and arrangement of crystals and, further, it may participate in the induction of new crystals. The formation of compartments during shell growth accounts for the uniform thickness, preferred exhibited orientation and mineralogy of the crystals as well as other features exhibited by the mature nacre.This investigation was aided (in part) by Grant DE-01825, N.I.D.R., U.S.P.H Service.     

天然蜂蜜联合珍珠粉用于压疮伤口换药的疗效观察

目的 探讨天然蜂蜜加珍珠粉在促进压疮伤口愈合中的应用效果。方法 选取笔者所在医院脑病科住院的50例压疮患者,按随机数字表法将患者分为对照组和观察组,各25例。对照组根据伤口情况选择相应的新型敷料,观察组在创面涂抹2∶1配比的蜂蜜加珍珠粉混合液,观察2组伤口愈合情况和治疗效果。结果 观察组伤口愈合情况和疗效均好于对照组(F_组间=189.722,P＜0.001;Z=-2.608,P=0.007)。结论 蜂蜜加珍珠粉用于压疮伤口换药疗效显著,值得临床推广应用。     

珍珠层聚乳酸人工骨复合成骨细胞体内异位成骨研究

目的探讨珍珠层聚乳酸(nacre／polylactic acid，N／P)人工骨与同种异体成骨细胞复合，植入体内后异位成骨的作用机制，以及作为骨组织工程支架材料的可行性。方法成年雄性新西兰大白兔18只，按2、4和8周3个时间点随机分成3组，每组6只。将体外培养的同种异体新西兰大白兔成骨细胞，种植到N／P人工骨材料上，并植入每只兔左侧背部皮下为实验组；以不复合成骨细胞的N／P人工骨材料植入右侧背部皮下作对照，分别于植入后不同时间点取材，经大体观察、组织学检查和免疫组织化学方法检测。结果实验组2周时材料周围有少许炎性细胞聚集，4周时有类骨质形成，8周时有成熟骨组织形成，其中可见骨髓腔；对照组2、4周时仅见大量纤维组织长入材料内，8周时材料内纤维组织增多，但无成骨发生。结论N／P人工骨可作为理想的骨组织工程支架材料。     

成骨细胞在珍珠层复合人工骨表面的粘附和增殖

目的　评价人成骨细胞在珍珠层聚乳酸人工骨上的粘附能力。方法　将珍珠层聚乳酸人工骨与人成骨细胞体外复合培养 ,采用倒置相差显微镜、扫描电镜、透射电镜及流式细胞仪检测 ,观察人成骨细胞在珍珠层聚乳酸人工骨上的粘附能力。结果　珍珠层聚乳酸人工骨与人成骨细胞体外复合培养 1周后 ,细胞通过伪足贴附于人工骨表面。透射电镜下成骨细胞形态正常 ,胞浆内有丰富的粗面内质网和线粒体 ,并可观察到细胞之间形成的连接。流式细胞仪检测结果显示 ,附着在珍珠层复合人工骨的成骨细胞增殖指数增高。结论　珍珠层复合人工骨材料有利于成骨细胞的粘附、增殖和分化     

Impact of head and neck cancer on partner's sociability

Introduction“Sociability” is defined as the range of experiences linking the subject to others. This is the first study to focus specifically on the impact of head and neck cancer on the sociability of patients’ partners.MethodData were collected via a dedicated questionnaire sent to patients’ partners. The main endpoint was partner's self-assessment of the impact of the patient's disease on the partner's everyday life. The impact on sociability was analyzed with respect to: the circle of friends (friendship environment), unknown environment, known outside environment, necessary environment, and solitary activities.ResultsTwo hundred and seventy partners responded. Their everyday activities were impacted by the patient's disease in 71.5% of cases. The friendship environment was badly affected in 46.4% of cases. The unknown environment was affected in 44.0% of cases. Social practices related to the known outside environment were affected in 67.8% of cases, and the necessary environment in 26.0%; the number of solitary activities increased in 35.6% of cases. Social impact on patients’ partners was thus considerable.     

钩藤、珍珠母在配合壮颈康复剂治疗椎动脉型颈椎病中的效用研究

目的：观察钩藤、珍珠母在配合壮颈康复剂治疗椎动脉型颈椎病中所起的效用。方法：将22只造模成功的椎动脉受压模型兔随机分为3组分别用壮颈康复剂的基础方加钩藤、珍珠母（Ⅰ组），壮颈康复剂的基础方（Ⅱ组），钩藤、珍珠母（Ⅲ组）灌胃14d后测血浆内皮素、血黏度。结果：Ⅰ组的血浆内皮素、血黏度测值明显低于Ⅱ组、Ⅲ组的测值。结论：在临床使用壮颈康复剂时，若患者有头晕症状时加用钩藤、珍珠母可提高疗效。     

The growth of nacre in the abalone shell

The process of mineral formation following periods of growth interruption (growth bands) is described. Flat pearl implantation as well as a new trepanning method are used to observe the transitory phases of calcium carbonate which nucleate and grow during this process. An initial random nucleation of the aragonite polymorph is observed followed by a transition towards spherulitic growth. During this transition the animal forms the structure of the shell through both mechanical and chemical actions. About 6 weeks after implantation a steady-state growth of aragonite tiles begins after shorter and more irregular tiles cover the outer surface of the spherulites. The growth rate of aragonitic spherulite during this transition period was calculated to be approximately 0.5 microm per day. An organic scaffolding is observed during the steady-state growth of tiled aragonite. Observations of mineral growth following the deposition of these membranes confirm the presence of mineral bridges originating from subsurface tiles and extending through the organic matrix, confirming the growth model proposed by Sch?ffer et al. [Sch?ffer TE, Ionescu-Zanetti C, Proksch R, Fritz M, Walters, DA, Almqvist N, et al. Does abalone nacre form by heteroepitaxial nucleation or by growth through mineral bridges? Chem Mater 1997;9:1731-40]. Field emission scanning electron microscopy of fractured deproteinated nacre shows the presence of mineral bridges existing between individual layers of tiles. Transmission electron microscopy provides further evidence of mineral bridges.     

新型骨替代材料-珍珠层的生物相容性研究

[目的]研究珍珠层的生物相容性。[方法]在体外培养的第3代成骨细胞中分别加入珍珠层（实验组）、橡胶（对照组）的材料浸提液，观察细胞形态、细胞膜和超微结构的变化；通过BrdU核掺入法检测细胞增殖情况、通过MTT法检测成骨细胞代谢活性。[结果]实验组细胞形态及细胞结构良好、细胞膜完整；对照组中细胞形态发生改变，细胞膜及胞浆内细胞器均有破坏；BrdU及MTT检测结果显示珍珠层对人成骨细胞的增殖和代谢活性无阻滞作用。[结论]珍珠层具有良好的生物相容性，可作为骨替代材料应用于骨缺损修复。     

珍珠层人工骨促进成骨细胞的体外成骨能力

目的:研究珍珠层人工骨对人成骨细胞体外成骨能力的影响。方法:将珍珠层人工骨、聚乳酸(对照组)与人成骨细胞共同培养,观察细胞形态、细胞活性、碱性磷酸酶(ALP)活性和基质钙化情况。结果:实验组在细胞形态、细胞活性等指标与对照组相比差异无显著性;实验组在培养7d及14d后ALP阳性细胞数多于对照组;培养21d后可观察到骨结节,对照组没有骨结节产生。结论:珍珠层人工骨可促进成骨细胞的体外成骨能力。