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1.
背景:韧带和其他生物软组织一样,具有黏弹性特性,其应力松弛和蠕变黏弹性特性是为适应人的生理功能需要而存在的。研究说明骨性关节炎对韧带力学性能具有一定影响。 目的:比较正常和骨性关节炎动物模型内侧副韧带的应力松弛流变特性,确定骨性关节炎对内侧副韧带应力松弛特性的影响。 方法:以闭合关节刻痕法复制骨性关节炎动物模型,取正常和骨性关节炎动物模型大鼠膝关节内侧副韧带各10个试样,进行应力松弛实验。应力松弛实验的应变增加速度为5%/s。设定实验时间为7 200 s,采集100个数据,观察应力松弛数据和曲线、应力与时间的变化规律,以一元线性回归分析的方法处理实验数据。 结果与结论:正常组和病态组试样应力松弛最初600 s变化较快,之后应力缓慢下降,正常组7 200 s应力松弛量0.47 MPa,病态组7 200 s应力松弛量0.29 MPa。模型组7 200 s应力松弛量显著低于正常组(P < 0.05),且应力松弛曲线是以对数关系变化的。说明骨性关节炎时可以使膝关节对内侧副韧带应力松弛量降低,对膝关节应力松弛特性具有一定影响。  相似文献   

2.
从应力松弛力学特性角度对棘间韧带和黄韧带进行定量分析,为人工韧带材料研究和韧带损伤吻合手术提供应力松弛力学参数。将标本装夹于软组织夹具中,之后装夹于电子万能试验机夹头内,驱动机器以1%/s的应变增加速度对标本施加拉应变,在36.5℃温度场下进行实验,采集90个数据,实验结束后计算机自动输出7 200 s之间应力松弛数据和曲线。棘间韧带组7 200 s应力松弛量为1.06 MPa,黄韧带组7 200s应力松弛量为1.62 MPa。棘间韧带和黄韧带具有不同的应力松弛力学特性。  相似文献   

3.
目的 研究新鲜成人尸体髋关节髂股韧带和股骨头韧带的黏弹性力学性质,为临床提供生物力学参数.方法 取正常国人髂股韧带和股骨头韧带各10个试样进行应力松弛、蠕变实验.结果 得出了应力松弛、蠕变实验曲线,以回归分析的方法处理实验数据,得出了回归系数.结论 髂股韧带7200s应力松弛蠕变量显著大于股骨头韧带.  相似文献   

4.
背景:去卵巢大鼠脊椎骨会发生哪些应力松弛与蠕变及时间的变化规律? 目的:观察去卵巢骨质疏松对雌性大鼠承重骨黏弹性特性的影响。 方法:Wistar雌性大鼠44只随机等分为对去卵巢骨质疏松动物模型组和对照组。模型组大鼠于0周摘除卵巢,14周后对大鼠L4椎骨进行应变增加速度为1%/s的应力松弛实验和应力增加速度为0.01 MPa/s的蠕变实验,在7 200 s采集100个数据。 结果与结论:大鼠L4椎骨对照组7 200 s应力松弛量和蠕变量大于模型组(P < 0.05);同时大鼠L4椎骨应力松弛曲线是以对数关系变化的,蠕变曲线是以指数关系变化的。提示去卵巢骨质疏松大鼠椎骨黏弹性力学特性发生了改变。  相似文献   

5.
骨性关节炎动物模型外侧副韧带应力松弛特性的研究   总被引:1,自引:0,他引:1  
比较正常和骨性关节炎动物模型外侧副韧带的应力松弛流变特性,确定骨性关节炎对外侧副韧带应力松弛特性的影响.在日本岛津电子万能试验机上对正常和病态各8个试样进行应力松驰实验.应力松弛实验的应变增加速度为5%/s.设定实验时间为7 200 s,采集100个数,以一元线性回归分析的方法处理实验数据.结果表明:正常和病态组试样应力松弛最初600 s变化较快,之后应力缓慢下降,正常组7 200 s应力松弛量为2.231 Mpa,病态组7 200 s应力松弛量为2.458 Mpa.表明应力松弛曲线是以对数关系变化的,骨性关节炎对外侧副韧带应力松弛特性具有一定影响.  相似文献   

6.
文题释义:黏弹性力学:连续介质力学的重要分支,又称黏弹性理论,研究黏弹性物质的力学行为、本构关系及其破坏规律,以及黏弹性体在外力和其他因素作用下的变形和应力分布。聚合物、混凝土、金属、岩石、土壤、石油、肌肉、血液和骨骼等,在一定条件下既具有弹性性质又具有黏性性质,这种兼具弹性和黏性性质的材料称为黏弹性材料,含黏弹性固体与黏弹性流体,又可分为线性黏弹性体和非线性黏弹性体。线性黏弹性体的两种极端情况即为胡克体(遵循胡克定律)和牛顿流体(遵循牛顿粘性定律)。 生物力学:是应用力学原理和方法对生物体中的力学问题定量研究的生物物理学分支,其研究范围从生物整体到系统、器官(包括血液、体液、脏器、骨骼等),从鸟飞、鱼游、鞭毛和纤毛运动到植物体液的输运等。 物力学的基础是能量守恒、动量定律、质量守恒三定律并加上描写物性的本构方程。生物力学研究的重点是与生理学、医学有关的力学问题,依研究对象的不同可分为生物流体力学、生物固体力学和运动生物力学等。 背景:以往对改性玻璃离子水门汀的力学性能研究多以压缩、弯曲实验居多,关于玻璃离子水门汀加入锶羟基磷灰石后的应力松弛、蠕变实验研究鲜有报道。 目的:对比分析传统玻璃离子水门汀、复合树脂釉质粘接剂、改性玻璃离子水门汀的应力松弛、蠕变特性。 方法:按质量比15%向玻璃离子水门汀中加入掺锶羟基磷灰石,制备改性玻璃离子水门汀。制作改性玻璃离子水门汀、复合树脂釉质粘接剂与传统玻璃离子水门汀试样,3组各取10个试样进行应力松弛实验,另取10个试样进行蠕变实验。 结果与结论:①应力松弛实验7 200 s时,传统玻璃离子水门汀组应力下降了1.18 MPa,复合树脂釉质粘接剂组应力下降了1.39 MPa,掺锶羟基磷灰石复合玻璃离子水门汀组应力下降了1.38 MPa;传统玻璃离子水门汀组应力下降量小于掺锶羟基磷灰石复合玻璃离子水门汀组、复合树脂釉质粘接剂组(P < 0.05),掺锶羟基磷灰石复合玻璃离子水门汀组和复合树脂釉质粘接剂组应力下降量无差异(P > 0.05)。②蠕变实验7 200 s时,传统玻璃离子水门汀组应变上升了0.24%,复合树脂釉质粘接剂组应变上升了0.33%,掺锶羟基磷灰石复合玻璃离子水门汀组应变上升了0.32%;传统玻璃离子水门汀组应变上升量小于掺锶羟基磷灰石复合玻璃离子水门汀组、复合树脂釉质粘接剂组(P < 0.05),掺锶羟基磷灰石复合玻璃离子水门汀组试和复合树脂釉质粘接剂组应变上升量无差异(P > 0.05)。③结果表明,15%掺锶羟基磷灰石提高和改善了玻璃离子水门汀的黏弹特性,有利于其与黏结物体的黏结,有利于提高黏结强度。 ORCID: 0000-0003-1024-5733(丁洁) 中国组织工程研究杂志出版内容重点:生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程  相似文献   

7.
前交叉韧带粘弹性特性的实验研究   总被引:2,自引:0,他引:2  
目的 探讨前交叉韧带的力学性能和粘弹性行为与时间的变化规律,为研究人工韧带提供生物力学参数。方法 对正常国人新鲜尸体膝关节前交叉韧带进行系统的拉伸、应力松驰、蠕变实验,得出最大载荷、强度极限、最大应变、弹性模量等;还得出了应力松驰、蠕变实验数据和曲线,归一化应力松驰函数、蠕变函数数据和曲线。并得到7200s时的蠕变量和应力松驰量。结果 ①前交叉韧带在实验中表现出典型的松弛、蠕变现象,说明其粘弹性性质在膝关节运动中起着重要的缓冲作用。②最初600s时应力应变的变化幅度较大,之后应力缓慢下降,应变缓慢上升,前交叉韧带7200s时应力松弛量1.05Mp,蠕变量为6.82%。结论 前交叉韧带具有良好的粘弹性力学性质。其粘弹性力学行为是为了适应其所在解剖部位的功能需要。  相似文献   

8.
正常与病态股骨头应力松弛特性的对比分析   总被引:1,自引:1,他引:0  
比较正常股骨头和股骨头坏死后股骨头应力松弛性质,为人工关节研究和髋关节置换术提供应力松弛参数。在日本岛津电子万能试验机上对正常与病态股骨头各8个试样进行应力松弛实验。模拟人体温在36.5℃的温度场下进行实验,以5%/s的应变增加速度对标本施加应变,设定时间为7 200 s,采集100个实验数据。采用三参数模型计算应力松弛方程。观察应力松弛曲线和7 200 s应力松弛量。股骨头在最初600 s变化较快,之后应力缓慢下降,正常组7 200 s应力松弛量为0.31 MPa,病态组7 200 s应力松弛量为0.22 MPa,病态组7 200 s应力松弛量显著低于正常组(P<0.05)。股骨头坏死后打乱了松质骨头骨小梁的正常排列,骨量丢失,从而对应力松弛特性造成影响。应力松弛数据可以定量地说明坏死股骨头应力松弛特性差。  相似文献   

9.
比较正常股骨头和股骨头坏死后股骨头应力松弛性质,为人工关节研究和髋关节置换术提供应力松弛参数。在日本岛津电子万能试验机上对正常与病态股骨头各8个试样进行应力松弛实验。模拟人体温在36.5℃的温度场下进行实验,以5%/s的应变增加速度对标本施加应变,设定时间为7 200 s,采集100个实验数据。采用三参数模型计算应力松弛方程。观察应力松弛曲线和7 200 s应力松弛量。股骨头在最初600 s变化较快,之后应力缓慢下降,正常组7 200 s应力松弛量为0.31 MPa,病态组7 200 s应力松弛量为0.22 MPa,病态组7 200 s应力松弛量显著低于正常组(P<0.05)。股骨头坏死后打乱了松质骨头骨小梁的正常排列,骨量丢失,从而对应力松弛特性造成影响。应力松弛数据可以定量地说明坏死股骨头应力松弛特性差。  相似文献   

10.
研究了正常国人8具新鲜尸体颈椎后纵韧带C1-C4、C4-T1的黏弹性力学性质.对C1-C4、C4-T1段后纵韧带进行拉伸应力松弛、蠕变实验.得出了C1-C4、C4-T1后纵韧带的应力松弛、蠕变数据和曲线.对应力松弛、蠕变数据进行归一化处理,得出了归一化应力松弛函数蠕变函数及曲线.对实验数据进行回归分析,得出了回归系数.还对后纵韧带C1-C4段、C4-T1段试样进行单向拉伸实验,得出了后纵韧带的拉伸破坏载荷、伸长比、拉应力、拉应变等,对应力应变数据以多项式,用最小二乘法进行拟合,得出其应力应变关系公式及曲线.构建了后纵韧带的松弛函数K(λ、t)=G(t)T(e)(λ)表达式,对实验结果进行分析讨论.  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
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.  相似文献   

14.
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.  相似文献   

15.
Introduction: The etiology of atopic dermatitis (AD) is multifactorial with interaction between genetics, immune and environmental factors.

Areas covered: We review the role of prenatal exposures, irritants and pruritogens, pathogens, climate factors, including temperature, humidity, ultraviolet radiation, outdoor and indoor air pollutants, tobacco smoke exposure, water hardness, urban vs. rural living, diet, breastfeeding, probiotics and prebiotics on AD.

Expert commentary: The increased global prevalence of AD cannot be attributed to genetics alone, suggesting that evolving environmental exposures may trigger and/or flare disease in predisposed individuals. There is a complex interplay between different environmental factors, including individual use of personal care products and exposure to climate, pollution, food and other exogenous factors. Understanding these complex risk factors is crucial to developing targeted interventions to prevent the disease in millions. Moreover, patients require counseling on optimal regimens for minimization of exposure to irritants and pruritogens and other harmful exposures.  相似文献   


16.
Renal dysplasia and asplenia in two sibs   总被引:2,自引:0,他引:2  
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.  相似文献   

17.
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.  相似文献   

18.
Zusammenfassung Der Einfluß von verschiedenen Nahrungsmitteln auf Methoden zur Bestimmung von Adrenalin (AD), Noradrenalin (NA), Vanillinmandelsäure (VMS), Metanephrinen (MN), Homovanillinsäure (HVS) und 5-Hydroxyindolessigsäure (5-HIE) im 24 h-Harn zur Diagnose des Phäochromozytoms bzw. Karzinoid-Syndroms wurde untersucht. Die in die Untersuchung einbezogenen Nahrungsmittel waren: Tee, Kaffee, Mandeln, Ananas, Käse, Walnüsse, Vanillepudding, Bananen, Tomaten und Milchschokolade. Außerdem wurde der Einfluß des Zigarettenrauchens auf die Bestimmung von AD, NA, VMS und MN untersucht.Walnüsse führten zu einer starken Erhöhung der 5-HIE-Ausscheidung. Bananen erhöhten die Ausscheidung von AD, NA, VMS, MN und 5-HIE. Kaffee und Ananas bewirkten eine geringe Zunahme der MN-Werte. Rauchen von 20–30 Zigaretten/Tag beeinflußte keine der vier Variablen.Wenn die beschriebenen Methoden benutzt werden, sollte lediglich auf den Verzehr von Bananen und Walnüssen vor und während der Harnsammelperioden verzichtet werden, da die oberen Normgrenzen im Harn überschritten werden könnten. Ein Verzicht auf Kaffee und Ananas in normalen Mengen ist nicht erforderlich. Es besteht kein Anlaß, weiterhin die bisherigen umfangreichen Restriktionen der übrigen Nahrungsmittel beizubehalten.  相似文献   

19.
《Human immunology》2020,81(5):193-194
Huastecos or Teenek Amerindians are presently living at North East Mexico (San Luis Potosi State). They have probably one of the most ancient culture of Mexico and Central America together with Mayas and Olmec groups with which also show close relationships. Proximity to Atlantic Ocean/Mexican Gulf originated that Spaniards had very early contact with them at about 1519 CE or before. In the present paper we have aimed to study HLA gene profile which may be useful for HLA and disease epidemiology and transplant programs in Teeneks. HLA-DRB1*04:07, -DRB1*14:06 and -DRB1*04:11 have been found in high frequency like in other Amerindian groups. High frequency typical Amerindians HLA extended haplotypes have been found, such as A*02-B*35-DRB1*04:07-DQB1*03:02; A*68-B*39-DRB1*04:07-DQB1*03:02 and A*02-B*39-DRB1*04:07-DQB1*03:02; also new haplotypes have been described, like A*02-B*52-DRB1*04:11-DQB1*03:02, A*68-B*35-DRB1*14:02-DQB1*03:01 and A*68-B*40-DRB1*16:02-DQB1*03:01. Genetic proximity is observed not only to linguistically close Mayans, but also to Mazatecans, Mixtecans and Zapotecans, who speak an altogether different languages; it shows once more that genes and languages do not correlate. This population was greatly diminished after European contact between 1500 and 1600 years CE; in fact, North and South America First Inhabitants population was brought from 80 down to 8 million people because of diseases (i.e.: measles, smallpox or influenza), slavery and war.  相似文献   

20.
Direct oral anticoagulants (DOAC) are indicated for stroke prevention in atrial fibrillation and for the prevention and treatment of venous thromboembolism. As any anticoagulant, they are associated with a bleeding risk. Management of DOAC-induced bleeding is challenging. Idarucizumab, antidote for dabigatran, is currently available and is part of the therapeutic strategy, whereas antidotes for anti-Xa agents are under development. Activated or non-activated prothrombin concentrates are proposed, although their efficacy to reverse DOAC is uncertain. We propose an update on DOAC-associated bleeding management, integrating the availability of idarucizumab and the critical place of DOAC concentration measurements.  相似文献   

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