椎弓根螺钉长度变化对螺钉-骨复合体模型 应力影响的三维有限元分析研究

目的 利用三维有限元模型研究椎弓根螺钉长度变化对生理载荷下螺钉骨复合体模型的应用影响。方法 建立椎弓根螺钉和L1椎体的三维模型,并对其进行网格划分,设置椎弓根钉长度尺寸的变化范围。模拟生理载荷条件下,对不同长度尺寸的椎弓根钉有限元模型进行应力分析。结果椎弓根螺钉长度在30～50 mm范围内变化时,随着螺钉长度的增大,螺钉骨复合体模型的骨质部分承担的应力均减小,而螺钉承担的应力则增加。螺钉最大平均主应变出现在螺钉的尾端,皮质骨发生的最大平均主应力位置出现在螺钉与皮质骨接触面两侧,松质骨发生的最大平均主应力位置出现在螺钉头部与松质骨接触面两侧。当螺钉长度达到50 mm时,载荷力传递到皮质骨和松质骨分别减小了43.1%和42.3%,而螺钉上出现的则增加了38%。当椎弓根螺钉长度大于45 mm时,螺钉骨复合体模型各部分应力变化不明显。结论 椎弓根螺钉长度在30～50 mm范围变化时,在生理载荷下,椎弓根螺钉长度的增大有利于改善螺钉、皮质骨及松质骨上轴向应力的力学分布;只要骨量允许,临床选择椎弓根螺钉的长度应不小于45 mm。     

38例寰椎侧块滋养孔解剖测量与临床意义

目的　观察并测量寰椎侧块滋养孔的临床解剖学参数,为降低寰椎侧块螺钉固定术中血管损伤风险提供参考。 方法　随机选取38例正常干燥成人寰椎骨标本,观察寰椎侧块滋养孔（以直径≥1.0 mm为判定界限）的形态、数目、位置;测量滋养孔最大横径、纵径、深度,滋养孔外缘到横突孔内缘之间的距离等。 结果　38例寰椎标本中,95%存在滋养孔,42%呈圆形、8%呈横椭圆形、45%呈纵椭圆形;5%无滋养孔;79%左右两侧滋养孔对称,16%不对称。滋养孔最大横径为（2.16±0.86）mm,最大纵径为（2.82±1.03）mm,最大深度为（1.75±0.71）mm,滋养孔外缘到横突孔内缘之间的距离（8.61±1.46）mm,各测量指标左右两侧无显著差异。 结论　95%的寰椎左右两侧存在滋养孔,且均位于寰椎侧块的中间区域,椎弓根螺钉通道处;临床寰椎侧块螺钉固定时,螺钉的直径可参考（8.61±1.46）mm;螺钉通道距离寰椎侧块内缘（1.73±0.7）mm。     

髋臼后壁软骨面平行角重建螺钉置入安全性的CT扫描图像分析

目的　通过三维CT和计算机软件分析以髋臼后壁软骨面平行角为参考时螺钉置入的理想位置、方向和长度,以指导手术和导向器研发。 方法　回顾性分析2008年7月至2016年7月我院收治的不稳定髋臼后壁骨折螺钉、钢板双重固定患者15例,男11例,女4例;年龄21～52岁,平均36.5岁,对比双侧髋臼CT图像评估手术的复位效果,计算机软件统计分析以髋臼后壁软骨面平行角为参考时螺钉置入的理想位置、方向和长度,并区分后壁螺钉置入的相对危险区和相对安全区。 结果　髋臼后壁危险区宽度对照组为（9.56±1.74）mm,手术组为（9.57±1.71） mm,安全区宽度对照组为（31.34±2.73） mm,手术组为（31.53±2.60） mm;髋臼后壁软骨面平行角对照组为（63.05±3.89）°,手术组为（62.33±3.46）°,相对螺钉长度对照组为（31.36±2.75）mm,手术组为（31.67±2.61） mm;上述参数差异均无统计学意义（P>0.05）。 结论　所有病例手术复位效果良好,髋臼后外侧壁靠近髋臼缘侧1/4（约1 cm）范围内为螺钉置入的相对危险区,而位于内侧3/4（约3 cm）范围内为相对安全区域;髋臼后壁软骨面平行角约60°,螺钉相对长度约为3.1 cm,当长度超过3.1 cm左右,角度大于60°,且位于危险区时螺钉进入关节腔风险性增大,而螺钉以小于或等于60°角度在相对安全区内置入可避免螺钉进入关节腔。     

改良中空加压螺钉内固定治疗股骨颈骨折的有限元分析

目的建立中空加压螺钉固定股骨颈骨折的三维有限元模型,研究3枚中空加压螺钉的受力情况及改良螺钉内固定治疗股骨颈骨折时能否提供所需的力学强度。方法三维有限元模型采取三钉倒三角并与股骨干成127°的内固定方式,并模拟单腿站立时的受载情况;在Pauwels角分别为50°、60°、70°、80°时,计算3枚螺钉在不同位置(下面螺钉为1号,前上螺钉为2号,后上螺钉为3号)所受应力;选择受力最大的螺钉开侧孔,研究孔径大小、开孔方向对螺钉固定股骨颈骨折模型的影响。结果随着Pauwels角度的增加,每个中空加压螺钉上的应力增大;Pauwels角为80°时各个中空加压螺钉的应力达到最大值,1、2、3号螺钉所受应力分别为304、515、和154 MPa;当受力最大的2号螺钉开孔直径为1 mm,开孔方向避开150°～195°时,3枚螺钉所受应力均在安全范围内。结论从力学角度看,3枚螺钉受到不同应力,开侧孔设计的中空加压螺钉具有良好的生物力学性能,治疗股骨颈骨折手术安全可靠,而且可以通过中空和侧孔管道向骨折端注入药物,为促进股骨颈骨折愈合创造有利条件。     

AO松质骨拉力螺钉和组合松质骨拉力螺钉加压固定的生物力学

目的:比较AO松质骨拉力螺钉和组合松质骨拉力螺钉加压固定骨折后承受动态载荷的能力。方法:利用0.12 g/cm~3 Sawbone建立骨折模型,并用AO松质骨拉力螺钉和组合松质骨拉力螺钉结合接骨板分别加压固定,构建动态载荷装置;Electro Force~3510材料试验机给予周期动态载荷:峰/谷:150 N/100 N,每100周期峰值增加10 N,谷值在加载过程中维持不变,频率2 Hz。测量动态载荷完成1 mm位移载荷峰值及周期数。结果:组合松质骨拉力螺钉结合接骨板加压固定后发生1 mm位移载荷峰值及周期数显著优于AO松质骨拉力螺钉(P0.01)。结论:相对于AO松质骨拉力螺钉加压固定骨折,组合松质骨拉力螺钉加压固定更加可靠,可以承受更多的应力载荷。     

不同移动方式下隐形矫治器的三维有限元分析

目的采用有限元方法分析不同弹性模量、厚度、牙齿移动方式对隐形矫治器变形的影响,为正畸医生制定矫治方案提供理论依据。方法建立4种厚度、3种弹性模量共12种隐形矫治器有限元模型。对12种模型施加倾斜移动的位移载荷,分析矫治器最大Von Mises应力和变形量;对最适模型分别施加倾斜、平行以及压低移动的位移载荷,分析矫治器变形情况。结果最大Von Mises应力随弹性模量、隐形矫治器厚度的增加而增大,变形量随矫治器厚度增加而减小;倾斜和平行移动时,隐形矫治器均在拟移动牙齿对应部位有最大的变形,拟不动牙齿对应部位有的向唇侧外凸变形,有的向舌侧内凹变形;压低移动时,矫治器严重向牙冠顶端偏移。结论隐形矫治器最适厚度为0. 75 mm,临床上目前使用弹性模量816. 31 MPa隐形矫治器是合适的;在数字模型上将向唇侧外凸部位对应的牙齿舌侧面和向舌侧内凹对应的牙齿唇侧面增厚,用增厚后的数字模型制作隐形矫治器,优化矫治器。     

基于柠檬酸合成的新型可降解螺钉生物相容性和生物力学特性的研究

目的 探讨聚柠檬酸复合纳米羟基磷灰石（POC-Click-HA）制作的新型生物可吸收松质骨螺钉治疗比格犬股骨外髁骨折的生物相容性及生物力学特性。 方法 健康成年比格犬9只,雌雄不限,体重8~11 kg,制备双侧股骨外髁骨折（AO分型33.B1型）模型。右侧采用POC-click-HA可吸收松质骨螺钉固定,作为实验组;左侧采用聚消旋乳酸PDLLA可吸收松质骨螺钉固定,作为对照组。术后观察实验动物一般情况,分别于术后4周、8周、12周处死3只动物,取材行大体观察、Lane-Sandhu组织学评分及生物力学分析。 结果 实验动物均存活至实验完成。大体观察两组骨折无移位,均于12周愈合,POC-click-HA组螺钉可见有新生骨组织从螺钉表面向内部生长。术后3个时间点对骨折部位进行Lane-Sandhu组织学评分,两组螺钉之间无统计学差异（P>0.05）。生物力学测试,4周POC-click-HA组钉-骨界面最大载荷低于PDLLA组（P<0.05）,8周和12周两者无显著差异（P>0.05）。 结论 POC-click-HA松质骨螺钉具有良好的生物相容性,生物力学性能满足固定比格犬股骨外侧髁B1型骨折。     

髋臼四边区上界置钉安全区域的影像解剖学研究

目的　通过对髋臼四边区三维重建模型进行解剖参数测量和从上方置入虚拟螺钉,明确四边区骨折螺钉固定的安全区域。 方法 用Mimics软件对50例（100侧）骨盆CT数据进行三维重建,切割出髋臼四边区三维模型,测量四边区解剖参数,确定置钉危险区域,并在四边区上界模拟置钉,计算其安全角度。 结果　P1螺钉最大后倾角男性为（7.63±5.47）°,女性为 （6.18±5.16）°,P5螺钉最大前倾角男性为（7.50±6.09）°,女性为（7.30±6.54）°,两者男女间差异均无统计学意义。P2、P4螺钉内外倾安全范围男性分别为（7.60±2.93）°、（16.88±5.61）°,女性分别为（7.96±2.98）°、（15.82±5.94）°,男女间差异均无统计学意义。男、女性分别有13侧及28侧P3螺钉安全范围很小,只能以固定角度置入,固定角度均值男性为（-0.22±2.87）°,女性为（-5.62±4.48）°,其差异有统计学意义。剩余59侧（男37侧,女22侧）P3螺钉安全范围男性为（5.39±2.60）°,女性为（4.06±2.58）°,其差异无统计学意义。 结论　P3为四边区上界最危险进钉点,距离起点约27 mm,若术前Mimics软件测量显示四边区骨质最薄处厚度男性小于4.47 mm,女性小于3.56 mm,则拧入长度小于14 mm或12 mm的短钉或空置。     

下颌骨内外侧面副孔分布的比较研究及临床意义

目的　通过对国人下颌骨内外侧面副孔的数量及分布特征的比较研究 ,探讨其与肿瘤浸润的关系。方法　将74块下颌骨的内外侧面分为 2区 6部 ,在 1 0～ 2 0倍显微镜下观察各区、部的副孔数。结果　副孔的数量在不同的标本上相差很大 ,内、外侧面相应各区各部的副孔数比较 ,经U检验 ,P <0 0 0 1 ,差异显著 ,内侧面多于外侧面。结论　副孔为肿瘤由骨皮质表面进入松质骨提供了直接通路 ,内侧面副孔数显然多于外侧面 ,为肿瘤细胞由内侧面骨皮质表面入侵松质骨提供了有利途径     

空心螺钉与重建钢板固定耻骨联合分离的生物力学稳定性比较

目的对空心螺钉与重建钢板固定耻骨联合分离的生物力学性能进行测试,为临床应用提供理论依据。方法取温州医学院防腐正常成人骨盆标本15具,随机分成3组。自第5腰椎水平及双大腿中上2/3处将尸体横断。耻骨联合处切开,并将单侧骶棘韧带、骶结节韧带、骶髂前韧带切断,模拟Tile B1型骨盆骨折,依次分别采用5孔重建钢板和6.5 mm空心螺钉内固定治疗耻骨联合分离。将标本固定于生物力学试验机,在腰5椎体上方对其进行垂直轴向压缩生物力学测试,最大负荷达400 N,比较耻骨联合分离的位移程度。结果 3.5 mm 5孔重建钢板和空心螺钉固定,均可显著减少耻骨联合的分离,恢复骨盆环的力学稳定性。其中3.5 mm 5孔重建钢板加4枚皮质骨螺钉于耻骨联合上方固定组,耻骨联合位移为(0.944±0.983)mm,空心螺钉髓内固定组耻骨联合分离为(-0.03±0.378)mm,两者之间存在统计学显著性差异(P0.05)。结论空心螺钉在生物力学稳定性上优于5孔3.5 mm重建钢板。空心螺钉具有良好的生物力学性能,固定可靠,符合生物学固定的原则。     

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.     

The universal muscular chain reaction,muscle spasm,Torsions, ruptures and extravasations. Chameleons of pathology and some manifestations of simple muscular disorders

Most bodily functions require the coordinated actions of complementary and supplementary paired muscle groups. Where this essential muscular cooperation is lacking, hollow organs may burst and others become literally screwed up, giving rise to many similar spastic diseases such as Torticollis, Twisted ovarian cyst, Torsion of the Testis, Volvulus of the intestines, Varicose Veins, Megacolon, Aortamegaly, Scoliosis, Erb's Palsy, Peyronie's Disease, Main-en-Griffe, Undescended Foot (Pes Cavus), Talipes, Strabismus. Spasm is “panenepidemic” and unclassified examples of Torsion Dystonia and Dyskinesia really are as common as debt and taxes.     

'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.     

Hypo- und Hypermagnesämie aus kardiologischer Sicht

Zusammenfassung Eine Reihe pathologischer Zustände bedingen Magnesiummangel. Zustände mit Hypermagnesämie sind ebenfalls bekannt, doch wesentlich seltener. Für den Kardiologen beachtenswert ist, daß unter Therapie mit bestimmten Diuretica bei Herzinsuffizienz, bei Herzinfarkt, Kardiomyopathie, Digitalisintoxikation und bestimmten Herzrhythmusstörungen Hypomagnesämie beobachtet wurde. Leider kann in der klinischen Routine nur ein extracelluläres Magnesiumdefizit durch Serumbestimmungen gemessen werden; über Magnesiummangel einzelner Organe kann nichts ausgesagt werden. Hinweise für Magnesiummangel geben aber neben der Messung des Serumspiegels Anamnese, klinischer Befund, bestimmte EKG-Veränderungen wie auch evtl. Hypokalämie, ein Zustand, bei dem sich oft — besonders bei Aldosteronismus — parallele Veränderungen zeigten.Tierexperimente deuten darauf hin, daß infarktähnliche Läsionen unter Magnesiummangel entstehen, doch ob Herzinfarkt beim Menschen durch Magnesiummangel ausgelöst werden kann, ist noch ungeklärt. In Leichenherzen zeigte sich im Infarktgebiet neben Calciumakkumulation signifikanter Magnesiumverlust, wobei unklar blieb, ob sich Ursache oder Folge des Infarktes widerspiegelten. Falls ein ursächlicher Zusammenhang besteht, ist er im Myokardstoffwechsel selbst zu suchen, wie bei der Alkoholkardiomyopathie, wo myokardialer Magnesiummangel zumindest als pathogenetischer Teilfaktor anerkannt wird. Andererseits versucht man aber auch Beziehungen zwischen Atherosklerose, Blutgerinnung und Hypomagnesämie herzustellen, in der Meinung, daß Magnesiummangel auch über den coronaren Pathomechanismus des Herzinfarktes wirken könnte. Sicher scheint, daß gewisse EKG-Veränderungen und Herzrhythmusstörungen durch einen irritierten Magnesiumhaushalt bedingt sein können, da sie bei Gabe bzw. Entzug von Magnesium verschwinden. Daß Magnesiummangel die Glykosidtoleranz verringert, wird tierexperimentell bestätigt. Unter Hypomagnesämie bewirkt Acetylstrophanthidin eher und länger Rhythmusstörungen als ohne, außerdem lassen diese sich durch Magnesiumgaben eliminieren. Da in gewissen Fällen spontane und digitalisinduzierte Herzrythmusstörungen durch Magnesiuminjektionen beseitigt wurden, scheint Magnesium als Therapeuticum angebracht. Einsatz verschiedener Magnesiumsalze bei Angina pectoris, degenerativen Herzerkrankungen und Herzinsuffizienz ohne geprüften und offensichtlich gestörten Magnesiumhaushalt ist fragwürdig, weil keine eindeutigen klinischen Erfolgsbeweise vorliegen. Immerhin mag es aber larvierte, durch Serumbestimmungen nicht erfaßbare Mangelzustände geben. Allgemein erscheint es aus kardiologischer Sicht ratsam, den Magnesiumhaushalt zu überwachen und in entsprechenden Fällen auszugleichen, um möglichen Myokardläsionen oder fatalen Herzrhythmusstörungen entgegenzuwirken.     

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.     

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.