陶瓷对陶瓷人工髋关节的磨擦界面特征

背景：陶瓷对陶瓷人工髋关节假体在临床上已有一定的应用,在表面磨擦、磨损和润滑方面占有优势,具有很大的研发潜力。 目的：评价陶瓷对陶瓷人工髋关节表面磨擦、磨损和润滑特性。 方法：将金属对超高分子量聚乙烯、金属对金属以及陶瓷对陶瓷人工髋关节假体的磨损界面研究进行分析,了解氧化铝陶瓷材料的结构特点、制备工艺以及磨损参数,并分析陶瓷对陶瓷人工髋关节置换治疗的效果,与其它假体材料进行对比。 结果与结论：①金属对超高分子量聚乙烯人工髋关节抗磨损性能差,使磨损颗粒进入关节和周围组织,造成骨溶解和松动。②金属对金属人工髋关节的磨损性能较金属对超高分子量聚乙烯假体有很大改善,骨溶解的发生率非常少,但由于磨损颗粒可散布于体内各脏器和体液中,使用时要注意避免发生过敏反应和毒性。③体外试验和体内试验证明陶瓷对陶瓷人工髋关节具有良好的摩擦、磨损、润滑性能,临床治疗长期随访结果显示陶瓷对陶瓷人工髋关节假体置换后无磨损颗粒,不会发生骨溶解。对于年龄较小,并且对髋关节活动度有较高要求的患者,陶瓷对陶瓷人工髋关节是治疗的首选。随着陶瓷对陶瓷人工髋关节假体设计和材料学的发展,通过改进假体的机械学特性,提高摩擦界面的耐磨性能和润滑机制,陶瓷对陶瓷人工髋关节假体的远期临床疗效将更加满意。     

金属对金属人工髋关节的磨损预测

目的发展复杂动态载荷与瞬态运动条件下的球面共型接触硬对硬人工髋关节的磨损预测模型,并用于典型的金属对金属人工髋关节在复杂三维生理运动条件下的磨损预测研究。方法建立有限元模型用于接触力学问题求解,采用固定-跟踪法(fixed-tracked method)完成具有三维欧拉运动的人工髋关节双侧界面动态磨损几何再现及相应的接触与磨损问题模拟的数值交换。结果磨损预测表明,磨损导致金属对金属人工髋关节接触界面几何由球面向非球面过渡,接触区域随磨损周期而增大,接触压力变化趋于平缓、最大接触压力逐渐减小。结论本研究所发展的三维复杂动态、具有双侧界面几何磨损变化的人工髋关节磨损预测模型,能够很好地进行金属对金属髋关节磨损数值预测模拟实验,为认识人工髋关节磨损机理提供了新的方法。     

天然与人工关节中的摩擦学问题

对当前国内外有关天然和人工关节摩擦学的研究工作进行简要的综述,包括：摩擦学的起源于定义,以及人体生物摩擦学研究的内容;关节润滑分析;MOP、MOM、COC人工关节磨损寿命研究;天然软骨的摩擦学研究;人工关节与宿主骨结合界面的微动摩擦学研究;人工滑液的研究等。文中重点列举了中国关节摩擦学研究者的成果。     

人工髋关节负重面材料的生物特性及其临床应用

背景：人工髋关节假体材料对髋关节置换的成功率及对患者治愈率起到决定性作用。 目的：评价不同组合方式髋关节负重面材料的性能及置入体内与机体的生物相容性。 方法：以“全髋关节置换,人工髋关节,金属,陶瓷,聚乙烯,生物相容性,临床应用;total hip replacement,Artificial hip,prosthetic materials,Biocompatibility,clinical application”为关键词,应用计算机检索2001-01/2011-12万方数据库、PubMed 数据库有关人工髋关节负重面生物材料与宿主生物相容性的文章。 结果与结论：金属-超高分子量聚乙烯组合是目前常用的组合,也是衡量其他组合的金标准,但其磨损颗粒引起周围组织反应导致骨溶解和无菌性假体松动;金属-高交联聚乙烯、金属-金属、陶瓷-陶瓷和陶瓷-聚乙烯组合均在一定程度上减少了磨损,但金属离子毒性、陶瓷脆性、造价高等仍然是需要解决的问题。理想的负重面材料应具有良好生物相容、耐蚀性、耐磨性、耐疲劳性、强韧性好等特点,目前人工髋关节负重面组合材料各有优缺点。因此,临床医师针对不同的患者,采取个体化治疗原则,综合患者病情和经济状况等多方面因素,选择合适假体组合类型,以期达到最佳临床疗效。     

非球面人工髋关节接触力学

目的由于受制造技术的局限性、可能的设计优化考虑以及临床应用的磨损等因素影响,人工髋关节轴承表面表现为非球面几何特征,可以利用有限元分析方法对非球面人工髋关节的接触力学行为进行研究。方法对球面网格数据模型进行非球关节面重建,研究不同取向椭球面股骨头对球面髋臼几何特征的非球面金属对金属人工髋关节的接触力学表现。结果非球面股骨头接触区域中心位置的平均曲率半径在一定范围内增大时,能有效降低相应关节接触面上的最大接触压力,同时接触面积有所增加;在同样载荷下,髋臼相对股骨头不同倾斜状态对非球面股骨头的接触压力峰值和面积影响较小,但压力分布有所不同。结论良好地控制人工髋关节的非球表面特征,有利于改善人工髋关节最大接触压力幅值大小和接触区域分布。所发展的非球面人工髋关节接触模型及数值模拟过程能够有效地运行,这为非球面关节动态接触及磨损预测问题研究提供了条件。     

金属对金属髋关节置换术后金属离子相关问题研究进展*

金属对金属(metal-on-metal,MOM)髋关节置换术主要包括金属对金属全髋关节置换术(metal-on-metal totalhip arthro-plasty,MOM-THA),大头径金属对金属全髋关节置换术(large-diameter head total hip arthroplasty,LDH-THA)以及全髋关节表面置换术(hip resurfacing arthroplasty,HRA)。自新一代的MOM假体应用以来,临床效果满意,然而术后金属离子的释     

不同材料髋关节假体在髋关节置换中的应用

背景：金属材料、高分子材料和陶瓷材料等制作的人工髋关节关节都已成功应用于临床,产品也已经发展到比较成熟的阶段,但是每种材料依然存在各自的优缺点。 目的：评价不同材料髋关节假体的特点及临床应用。 方法：采用电子检索的方式在万方数据库中检索1999-01/2011-02有关髋关节假体材料的研究,关键词为“髋关节置换”。排除重复研究、普通综述或Meta分析类文章,筛选纳入18篇文献进行评价。 结果与结论：金属材料在髋关节置换中占有重要的地位,目前髋关节置换临床应用最多的是金属关节头和超高分子量聚乙烯髋臼的组合,但金属的弹性模量与人体骨骼相差甚远,导致应力遮挡效应,容易引起假体的疏松和不稳定;生物惰性陶瓷在活体内具有很高的稳定性和很好的机械强度,而生物活性陶瓷具有骨传导的特点以及与活骨整合的性能;复合材料假体因其可调的弹性模量和足够的力学强度,力学性能接近人体骨骼而逐渐被重视。但目前还缺乏生物相容性好、生物力学相容性好的理想假体材料。因此,应从改进人工髋关节设计和制造工艺,提高材料的耐磨性与力学性能,增强假体与宿主骨的结合性,减少应力遮挡,寻找新的人工髋关节假体材料等方面来提高置入物与宿主的生物相容性,从而能够更好地延长假体使用寿命。     

人工股骨头置换后的髋臼磨损

目的:探讨不同类型人工股骨头的临床应用特征、术后髋臼磨损及其影响因素和处理对策。方法:应用万方数据库和中国期刊全文数据库(CNKI),以"人工股骨头置换;全髋关节置换;髋臼磨损;临床意义;翻修技巧"等为检索词,检索1998/2010时限内与人工股骨头置换术后髋臼磨损有关的文献。排除重复研究或较陈旧文献。结果:依据纳入排除标准共保留文献24篇。临床常用的人工股骨头按材料类型不同分为金属合金股骨头与陶瓷材料股骨头。金属合金股骨头价格低廉,耐腐蚀,易于置入,但并发症严重;陶瓷股骨头安全性及有效性较高,但经济投入较高,不易临床推广。从临床效果来看,陶瓷股骨头引起髋臼磨损的发生率要远远低于金属合金类。髋臼磨损的影响因素涉及生物材料、假体设计、手术技巧等方面,全髋关节翻修为髋臼磨损的最后对策,需注意翻修技巧等。结论:陶瓷材料人工股骨头更适宜应用于人工股骨头置换术,其术后髋臼磨损的发生率较低。全髋关节翻修为髋臼磨损的最终治疗方案,其近、中期效果良好,长期效果有待进一步临床随访。     

人工髋关节关节面的磨损和生物陶瓷材料

人工髋关节的寿命和关节面的磨损密切相关。本文阐述了磨损、磨损颗粒和细胞因子在无菌性松动中的可能作用。比较了不同材料的性能。提出生物陶瓷材料在人工髋关节材料中的良好的性能和光明前景。     

金属对聚乙烯与陶瓷对聚乙烯人工髋关节负重界面的抗磨损性能比较

背景：人工全髋关节假体中,聚乙烯内衬假体以其稳定的质量和价格优势使用广泛,但聚乙烯磨损颗粒诱发骨溶解,进而导致假体的无菌性松动仍然是影响假体远期生存率的主要原因。 目的：以计算机辅助方法,测量金属对聚乙烯和陶瓷对聚乙烯负重界面组合假体的聚乙烯内衬线性磨损,比较2组不同负重界面组合抗磨损性能的差异。 方法：对1997/2005在南方医科大学附属南方医院行初次Zweymuller非骨水泥型假体系统人工全髋关节置换的患者48例共58髋进行随访。利用股骨头假体中心相对于髋臼杯开口平面轴线的矢量位移,来判断线性磨损的大小和方向。根据负重界面组合的不同分为金属对聚乙烯组(36髋)和陶瓷对聚乙烯组(22髋),比较2组之间聚乙烯线性磨损率的差别。 结果与结论：金属对聚乙烯组平均随访6.3年的线性磨损率为(0.20±0.11) mm/年,陶瓷对聚乙烯组平均随访4.6年的线性磨损率为(0.11±0.03) mm/年。排除年龄、随访时间、双侧股骨偏心距差距、线性磨损方向作为混杂因素的影响后,协方差分析显示金属对聚乙烯组的线性磨损率明显高于陶瓷对聚乙烯组(P=0.017)。提示陶瓷对聚乙烯负重界面组合相比金属对聚乙烯组合,在中期临床随访中展示出更加优良的抗磨损性能。     

Renal dysplasia and asplenia in two sibs

A family is reported in which two sibs, one male and the other female, both died within 24 hours of birth with enlarged polycystic kidneys. Postmortem histology in the second child showed gross renal dysplasia. In both children the pancreas was enlarged, nodular and cystic but the liver appeared macroscopically normal. In the second child, histological examination confirmed pancreatic fibrosis with cystic dilation of ducts, but showed portal fibrosis with bile duct proliferation in the liver.
This combination of findings is very reminiscent of those in a girl and her brother reported by Ivemark et al. (1959). The children reported here also showed absence or hypoplasia of the spleen, cardiac anomalies and other features of the Ivemark syndrome (Ivemark 1955), a quite different, usually sporadic, congenital disorder. It is suggested that the children described here have a distinct lethal congenital disorder, probably inherited in an autosomal recessive manner.     

Schizophrenia in a North Swedish geographical isolate, 1900–1977. Epidemiology, genetics and biochemistry

Over 200 schizophrenic patients belonging to three major and interrelated pedigree complexes have been investigated over the past 30 years in a North Swedish geographically isolated population, presently numbering about 6,000. An intensive investigation of a number of biochemical correlates and genetic markers in a few selected families belonging to one of the major pedigrees has indicated new strategies for the current research program.
Schizophrenia, as defined operationally, is significantly associated with decreased activities of two enzymes (1) blood platelet monoamine oxidase, (2) plasma dopamine-β-hydroxylase, and (3) with the genetic marker Gc² (group specific antigen). Both enzymes are subject to genetic variation. A positive score for linkage between schizophrenia and low plasma DBH activity has been calculated, but, so far, available data are insufficient for discrimination between linkage and partial contribution of genetically controlled low plasma DBH to the pathogenesis of the disease. Alternatively, both mechanisms could be involved.
As a model for continued research, schizophrenia is explained as based on a double dominant-recessive genotype (Aabb), representing a vulnerability which in about 50 % of cases develops into clinical schizophrenia. It is suggested that the dominant mutation (A) operates on or affects MAO activity, and that the recessive genotype (bb) is instrumental in low variates of DBH activity and very likely such variates within the normal range of physiological variation. Moreover, it is suggested that the combined effects of MAO- and DBH-reduced efficiency on the metabolism of e.g. dopamine could be an essential pathogenic mechanism for the schizophrenic illness which is segregating in this population.     

The dominant diseases of modernized societies as omega-3 essential fatty acid deficiency syndrome: Substrate beriberi

About 1900, modern food selection and processing caused widespread $\text{epidemics}$ of the B vitamin deficiency diseases of beriberi and pellagra which, for genetic reasons, often expressed as different diseases ranging from bowel and heart disease to dermatoses and psychoses. But the B vitamins merely help convert essential fatty acids (EFA) into the prostaglandin (PG) tissue regulators and it now turns out that, through hydrogenation, milling and selection of w3-poor southern foods, we have also been systematically depleting, by as much as 90%, a newly discovered trace Nordic EFA (w3) of special importance to primates and sole precursor of the PG3(4) series, even as a concurrent fiber deficiency increases body demand for EFA. Since substrate EFA is processed by many B vitamin catalysts, an EFA deficiency will mimic a $\text{panh}$ypovitaminosis B, i.e., a mixture of $\text{substrate}$ beriberi and $\text{substrate}$ pellagra resembling vitamin beriberi and pellagra but exhibiting as even more diverse $\text{endemic}$ disease. This would consitute a second stage of the Modern Malnutrition and explain why some workers now hold the dominant diseases of modermized societies to be new, nutritionally based, pellagraform yet lipid-related and to range, once again, from heart disease to psychosis. It is an assumption that our dominant diseases are unrelated to each other or are merely revealed by our diagnostic acumen and therapeutic success; and that hydrogenating millions of tons of food oils annually, to destroy the rancidity producing w3-EFA, is safe for $\text{primates}$. Extensive beriberiform disease is reported here in 32 typical cases taken from medical practice which responds strikingly to linseed oil supplements (60% w3-EFA) in confirmation of identical results in Capuchins.     

What will studies of Fulani individuals naturally exposed to malaria teach us about protective immunity to malaria?

There are an estimated over 200 million yearly cases of malaria worldwide. Despite concerted international effort to combat the disease, it still causes approximately half a million deaths every year, the majority of which are young children with Plasmodium falciparum infection in sub-Saharan Africa. Successes are largely attributed to malaria prevention strategies, such as insecticide-treated mosquito nets and indoor spraying, as well as improved access to existing treatments. One important hurdle to new approaches for the treatment and prevention of malaria is our limited understanding of the biology of Plasmodium infection and its complex interaction with the immune system of its human host. Therefore, the elimination of malaria in Africa not only relies on existing tools to reduce malaria burden, but also requires fundamental research to develop innovative approaches. Here, we summarize our discoveries from investigations of ethnic groups of West Africa who have different susceptibility to malaria.     

'Very sore nights and days': the child's experience of illness in early modern England, c.1580-1720

Sick children were ubiquitous in early modern England, and yet they have received very little attention from historians. Taking the elusive perspective of the child, this article explores the physical, emotional, and spiritual experience of illness in England between approximately 1580 and 1720. What was it like being ill and suffering pain? How did the young respond emotionally to the anticipation of death? It is argued that children’s experiences were characterised by profound ambivalence: illness could be terrifying and distressing, but also a source of emotional and spiritual fulfilment and joy. This interpretation challenges the common assumption amongst medical historians that the experiences of early modern patients were utterly miserable. It also sheds light on children’s emotional feelings for their parents, a subject often overlooked in the historiography of childhood. The primary sources used in this article include diaries, autobiographies, letters, the biographies of pious children, printed possession cases, doctors’ casebooks, and theological treatises concerning the afterlife.     

Guidelines for the Validation and Use of Immunoassays for Determination of Introduced Proteins in Biotechnology Enhanced Crops and Derived Food Ingredients

Recent advancements in agricultural biotechnology have created a need for analytical techniques to determine introduced proteins in crops enhanced through modern biotechnology techniques. These proteins are expressed in plant tissues and may be present in food ingredients. Immunoassays are ideally suited for protein detection and may be used as both quantitative and threshold methods. Microplate ELISA and lateral flow devices are two of the most commonly used immunoassay formats for agricultural biotechnology applications. This paper provides general background information and a discussion of criteria for the validation and application of immunochemical methods to the analysis of proteins introduced into plants and food ingredients using biotechnology methods. It is the result of a collaborative effort of members of the Analytical Environmental Immunochemical Consortium. This collaborative effort represents the combined expertise of several organizations to reach consensus on establishing guidelines for the validation and use of immunoassays. Further, the paper offers developers and users a consistent approach to adopting the technology as well as aid in producing accurate and meaningful results.     

Ultracryotomy: development and application (with examples from the yeast cytology) (author's transl)

The preparation steps usually necessary for obtaining ultrathin frozen sections of biological material (chemical prefixation, enclosing, cryoprotective treatment, freezing, sectioning, and post-staining the sections for transmission electron microscopy) are submitted to a critical analysis. The application of cryo-ultramicrotomy, in particularly for cytochemical purposes, is reviewed. Fundamental considerations of chemical prefixation and poststaining are supported by examples from yeast cytology. Furthermore, the efficiency of the cryo-ultramicrotomy (electron optical resolution of ultrastructural details) is demonstrated on yeast cells and protoplasts.     

HLA in North Colombia Chimila Amerindians

HLA-A,-B,-C,-DRB1 and -DQB1 alleles have been studied in Chimila Amerindians from Sabana de San Angel (North Colombian Coast) by using high resolution molecular typing. A frequent extended haplotype was found:HLA-A*24:02-B*51:10-C*15:02-BRB1*04:07-DQB1*03:02 (28.7%) which has also been described in Amerinndian Mayos Mexican population (Mexico, California Gulf, Pacific Ocean). Other haplotypes had already been found in Amerindians from Mexico (Pacific and Atlantic Coast), Peru (highlands and Amazon Basin), Bolivia and North USA. A geographic pattern according to HLA allele or haplotype frequencies is lacking in Amerindians, as already known. Also, five new extended haplotypes were found in Chimila Amerindians. Their HLA-A*24:02 high frequencies characteristic is shared with aboriginal populations of Taiwan; also, HLA-C*01:02 high frequencies are found in New Zealand Maoris, New Caledonians and Kimberly Aborigines from Australia. Finally, this study may show a model of evolutionary factors acting and rising one HLA allele frequency (-A*24:02), but not in others that belong to the same or different HLA loci.     

The universal muscular chamber. A basic unit of the genitourinary, cardiovascular, gastro-intestinal, skeletal, cutaneous, respiratory and other systems, endocameral hypertension; and spasm, the key to their idiopathic diseases and arthropathies

Starting with the integument, we see many organs are contractile sacs or multiples thereof, which tubes or bags constitute the major part of the entire body. Recognition of this basic unit and its characteristics sheds new light, individually and collectively, on many disorders previously considered unrelated. Muscular tears and perforations develop in the walls of these chambers, being no way peculiar to those organs, wherein, hydrochloric acid occurs. So, it is not necessary to explain the absence of excessive acid from patients who exhibit holes in the gastric, uterine, aortic, duodenal, rectal, pulmonary, retina, and other walls. Muscle, not acid is the great common factor relating idiopathic disorders in the gastrointestinal tract to each other and to similar diseases in other systems. When the units are linked together, the lesions tend to appear as arthropathies, i.e. at the joints. Rephrasing common-place observations, frees us from conventional, conceptual cul-de-sacs. An observation is only as good as its interpretation, so all possibilities must be considered, otherwise, we will remain blinded by our misconceptions.