3岁儿童C4-C5颈椎有限元模型开发及拉伸、弯曲验证

基于CT扫描,建立具有精确骨骼几何及详细椎间盘解剖学结构的3岁儿童C4-C5颈椎段有限元模型;参考成人颈部生物材料实验数据及相关成人与对比研究结果,采用缩放方法计算得到3岁儿童颈部组织材料参数;分别在准静态、动态拉伸以及准静态弯曲-伸展、侧向弯曲及轴向旋转载荷条件下,对模型进行验证。结果显示,准静态拉伸刚度为211.8 N/mm,动态拉伸最终失效力为759.9 N,最终失效位移为5.08 mm,均与实验值吻合良好;准静态伸展、弯曲、侧向弯曲及轴向旋转运动范围分别为9.75°、9.29°、3.79°和7.04°,均在实验基准数据允许的误差范围内,吻合良好。结论表明:该模型能较好地反映3岁儿童C4-C5颈椎段在准静态、动态拉伸以及准静态弯曲-伸展、侧向弯曲和轴向旋转载荷下的生物力学特性,具有较高的生物逼真度。     

6 岁儿童下肢长骨有限元模型验证及参数研究

研究在动态载荷下6岁儿童下肢长骨的损伤极限。分别对股骨、胫骨的有限元模型进行动态三点弯曲仿真试验,并通过有限元模型仿真试验与尸体试验结果的对比,探究相关参数对6岁儿童下肢长骨骨折的影响。仿真试验所得冲击块的撞击力 位移曲线走势与尸体试验的结果基本吻合,验证了该模型的有效性。股骨和胫骨失效时的撞击力分别为2.52和1.96 kN,位移分别为11.88和23.49 mm。与成人相比,儿童骨骼的弹性模量略低,并且骨骼韧性较好,使得撞击时发生骨折的风险相对降低。本研究为儿童下肢损伤机理及防护措施的研究提供了科学的基础数据。     

α1-抗糜蛋白酶基因Isehara-1、Isehara-2 突变型与儿童哮喘相关性研究

目的 了解α1-抗糜蛋白酶(AACT)基因Isehara-1、Isehara-2突变型与昆明儿童哮喘发生是否具有相关性。方法 应用聚合酶链反应(PCR)技术、基因测序方法，对30例昆明市汉族哮喘儿童厦20例正常儿童α1-抗糜蛋白酶基因外显子(exon)V进行检测。结果所有研究对象均未发现α1-抗糜蛋白酶基因Isehara-1、Isehara-2突变型。结论 α1-抗糜蛋白酶基因Isehara-1、Isehara-2突变型与30例昆明市汉族儿童哮喘发病无相关关系。     

斯氏针置入股骨头不同方式的生物力学分析

背景:对于不同年龄段的人群,股骨颈骨折有其不同的骨折线走向特点,有着不同的治疗策略。如何在手术治疗中提高复位质量、避免股骨头坏死及内固定失效,成为骨科学者面对的共同挑战。通过对股骨头颈部模型进行力学测试,期望获得相关数据,为提高复位稳定性及复位质量指明方向。目的:通过静态拉伸实验和疲劳实验得出斯氏针不同方式置入股骨头的力学特点。方法:选取天津正天医疗器械有限公司生产型号为ZLW02SJA的斯氏针,规格φ3.5*300 mm,样品材质为317不锈钢,按照2个步骤进行研究。步骤一:静态拉伸实验,使用1枚或者2枚斯氏针,按照前方或者侧方打入股骨头的方式组合,共计8种方案,每一方案将斯氏针打入Sawbone股骨头相应深度,以20 mm/min的速度对斯氏针进行拔出力测试,记录拔出力值。步骤二:疲劳拉伸实验,汇总前8次实验拔出力的平均值,取2个最大拔出力的75%值分别进行疲劳拉伸测试。结果与结论:(1)经过静态抗拔出力测试,得出抗拔出力最佳的2种方案为方案五和方案七,其中方案五的打入方式为自前而后,皮质骨厚度为4.3 mm,松质骨厚度为25.7 mm,斯氏针数量为2枚,置入深度为股骨头2/3;方...     

不同长度齿突对螺钉把持力的测试

目的 评价不同长度齿突骨折螺钉内固定的生物力学效果。方法 收集20具新鲜成人枢椎标本,按齿突螺钉固定技术钻孔形成针道,模拟齿突II型骨折,测量齿突端针道长度,置入螺钉后测试旋入力矩、最大轴向拨出力和刚度测试,解剖观察钉道骨质构成。结果 钉道长度8.3mm～12.3mm,钉道长度与螺钉最大拔出力相关回归分析：相关系数r=0.28, 回归方程式：Y=156.69+67.97X (Y:：钉道长 X：拔出力),大于10mm和小于10mm两组间旋入力矩、最大轴向拨出力和刚度t检验无统计学上差异(P>0.05),齿尖部由皮质骨构成。结论 齿突长度和骨折端的稳定度关系不密切、与最大轴向拨出力成正比关系但并不显著,短于1cm的齿突对螺钉仍有较好的把持力。     

儿童股骨近端解剖钢板生物力学及三维有限元分析

背景：以往的三维有限元研究多集中在成人骨科生物力学方面。 目的：以三维有限元方法分析儿童股骨近端解剖钢板固定股骨转子下骨折的生物力学性能。 方法：从6具儿童尸体上取股骨12根,X射线排除骨病后分为2组,实验组采用儿童股骨近端解剖钢板固定,对照组采用重建钢板固定。分别进行生物力学实验,测试其轴向压缩、扭转刚度、弯曲刚度。选取1名健康男性儿童进行螺旋CT扫描技术,获得股骨近端图像数据,建立儿童股骨近端三维有限元模型,并进行三维有限元力学分析。 结果与结论：在轴向压缩刚度、扭转刚度上儿童股骨近端解剖钢板与重建钢板两者比较差异无显著性意义(P > 0.05);在抗弯曲刚度上,两者相比差异有显著性意义(P < 0.05)。结果显示儿童股骨近端解剖钢板的抗压能力、抗扭能力上与重建钢板相当,而在抗弯曲能力上强于重建钢板。生物力学三维有限元分析显示儿童股骨近端解剖型钢板的设计符合生物力学原理,具有较好的强度、刚度和稳定性,能够满足对儿童股骨近端骨折固定的需要。儿童股骨近端解剖型钢板对固定股骨转子下骨折具有良好的生物力学性能。     

六角几何形和修复体台宽度对牙种植体静态和疲劳强度的影响

本研究通静态和疲劳试验,SEM评价修复体界面来评价骨和螺钉种植体的机械整合。实验采用直径4.0mm和5.0mmMaestroSystem种植体,为了模拟应力集中的最坏情况,每个种植体都用粗的(rough)钛等离子喷涂(TPS)涂层,设计并制作常规设计的桥基和末端帽(endcap)以确保恒定的弯曲矩(constantbendingmoment)位于种植体和桥基组装处。每个桥基螺钉在测试前1h和测试前5min各拧紧30Ncm。种植体在测试夹表面暴出2mm,长轴与加载针呈30°夹角以模拟临床上严重的单个牙弯曲力或悬臂载荷,种植体桥基连接体平台上方桥基长度为8mm。将一个环境室附着到伺服液压…     

转染TNF-α及其突变体的成纤维细胞的杀瘤效应

目的:比较跨膜型和分泌型TNF－α在体内的抗瘤效应。方法：将3种TNF－α基因（分泌型TNF－α突变体，S－TNFm、跨膜型TNF－α突变体，TM－TNFm和野生型TNF－α，Wt-TNF)通过逆转录病毒载体转染成纤维细胞NIH／3T3；并用Southern印迹、RT－PCR、流式细胞仪和生物活性检测等方法，从基因的整合、RNA转录、蛋白的表达及其生物学活性4个方面对转染细胞进行检测鉴定。在小鼠接种肿瘤细胞的第3天，于接种部位分别皮下注射表达TNF－α及其突变体的NIH3T3细胞，效／靶比为5：1或1：1，观察这3种TNF－α的体内抗瘤效应。结果：NIH3T3转染细胞可表达高水平的TNFα及其突变体。在体外，NIH3T3／TM－TNFm的固定细胞，NIH3T3／S－TNFm的上清、NIH3T3／Wt-TNF的固定细胞和上清均可有效杀伤肿瘤细胞H22。在体内，当效／靶比为5：1时，注射NIH3T3／TM－TNFm的抑瘤效果最强；而当效／靶比为1：1时，则NIH3T3／S－TNFm的疗效最好。此外，在过继治疗期间未见明显副作用。结论：上述结果提示跨膜型和分泌型TNF－α均可在体内有效杀瘤；但如效／靶比 适当，TM－TNF－α显示的杀瘤效应较S－TNF－α更强。     

抑瘤饮增加小鼠S180移植瘤巨噬细胞浸润及TNF-α和iNOS表达

目的动态研究中药复方抑瘤饮对小鼠S180移植瘤内巨噬细胞（Mφ）浸润及TNF-α和iNOS表达的影响，揭示其体内抗瘤免疫机制。方法Balb／c小鼠右腋皮下接种S180肿瘤细胞，24h后，抑瘤饮组小鼠每日灌服抑瘤饮，对照组小鼠每日灌服等量凉开水。分别于第10、加、30天和第40天杀鼠取瘤制成切片，免疫组化染色法检测肿瘤组织内Mφ浸润及TNF-α和iNOS表达，以图像分析系统对染色结果进行测定。结果所有4个时间点抑瘤饮组Mφ浸润均显著高于对照组；第10天时抑瘤饮组TNF-α和iNOS表达与对照组无差异，第20、30天和第40天时高于对照组。结论抑瘤饮体内抗瘤作用可能与增加肿瘤组织中Mφ浸润及TNF-α和iNOS表达有关。     

舒芬太尼用于腹部手术患者自控静脉镇痛的临床观察

目的探讨腹部手术病人自控舒芬太尼静脉镇痛的临床效果及安全性。方法选择气管内插管全身麻醉腹部手术患者计80例，ASA分级Ⅰ～Ⅱ级，年龄18～86岁，高中以上文化程度。随机分为两组，每组40例，一组为舒芬太尼镇痛组（S组），术后镇痛药物配方：舒芬太尼2μg／kg＋格拉司琼6mg加生理盐水至100ml；另一组为芬太尼镇痛组（F组），术后镇痛药物配方：芬太尼20μg／kg＋格拉司琼6mg加生理盐水至100ml。镇痛泵参数均设置为：负荷剂量4ml，背景输注速度1ml／h，自控剂量0．5ml，锁定时间15min。观察S组与F组的镇痛效果及不良反应。结果S组在各个时段静态和动态VAS评分均低于F组（P〈0．05）；S组镇静效果较F组评分略高，但两者差异无统计学意义（P〉0．05）；S组不良反应发生率少于F组（P〈0．01）；两组患者均未见明显的呼吸抑制发生。术后随访两组患者对镇痛效果的总满意度均在90％以上。结论腹部手术病人自控舒芬太尼静脉镇痛，具有良好的镇痛和镇静作用及安全性，且心血管的稳定性好，不良反应低。     

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.     

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.     

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.     

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.