缺血后处理对骨骼肌缺血再灌注损伤的保护作用

任何组织的缺血,只要达到一定时间和程度,必然会引起组织细胞的损伤.1985年McCord经过研究发现,长时间的组织器官缺血后的再灌注是一把"双刃剑",首先是再灌注挽救了缺血的组织器官,以防止进一步的缺血损伤,然而不可控的再灌注也引起了组织器官的再灌注损伤,故此提出了缺血一再灌注损伤这一概念.骨骼肌是组成肢体的重要组织之一,同时它对缺血十分敏感,人类骨骼肌在室温下完全缺血2.25 h就会出现不可逆的功能损害.在骨科的临床工作中,动脉断裂栓塞、断肢再植、应用止血带时间过长,都有可能造成严重的骨骼肌缺血,随后发生缺血再灌注损伤,从而影响患者肢体的存活,甚至造成截肢的后果.     

缺血-再灌注肺损伤动物模型的建立方法

缺血 再灌注肺损伤是指肺组织或其他组织器官遭受一定时间缺血后恢复血液灌流 (再灌注 ) ,肺组织损伤程度迅速增剧的病理现象。根据缺血组织器官的不同 ,再灌注肺损伤可分为两大类病因 ,一类是肺血管缺血后再灌注产生的肺组织损伤 ,如肺栓塞溶栓治疗、肺血栓内膜切除术、心肺移植术等 ;另一类为肺外组织器官缺血后再灌注导致肺组织损伤 ,如肢体手术、腹主动脉瘤手术等。由于血运重建后 ,反而引起肺组织损伤加重 ,有悖于治疗目的 ,因此开展缺血 再灌注肺损伤的研究和防治已愈来愈受到人们的重视 ,而建立良好的动物模型又是研究缺血 再灌注…     

预防肝脏缺血再灌注损伤的研究现状

1960年Jenn ings首先提出了缺血再灌注损伤(ischem i-a-reperfusion in jury)的概念:缺血后再灌注,不仅不能使组织、器官功能恢复,反而加重组织、器官的功能障碍和结构损伤,这种现象称为缺血再灌注损伤。Toledo-pereyra则指出:在临床移植中,再灌注损伤实际上是器官的供体维持、热缺血、保存、移植、再灌注期间总的损伤。再灌注损伤不仅见于临床,而且也为不同种属的大量动物实验所证明,在机体内,许多组织器官,如心、肾、肝、肺、胃肠、脑、肢体和皮肤等都可发生再灌注损伤。肝脏缺血再灌注损伤(H IR I)是肝脏外科中常见的病理过程,多发于…     

灯盏花在肢体缺血/再灌注致远隔多器官损伤的预防作用

目的观察灯盏花在肢体缺血/再灌注致远隔多器官损伤的预防作用.方法实验共分三组(1)再灌注组夹闭大鼠双侧股动脉,阻断循环2h后再灌注5h,建立双下肢缺血/再灌注模型;(2)灯盏花组大鼠每日腹腔注射云南灯盏花注射液1ml,共7天,后按再灌注组方法制作模型;(3)对照组行假手术处理.观察大鼠下肢骨骼肌、远隔器官胃、肾、肺、肝及脑组织超微病理改变、红细胞超氧化物歧化酶(SOD)含量、组织丙二醛(MDA)含量、血清谷胱甘肽(GSH)含量,并观察灯盏花对远隔器官损伤的预防作用和对自由基的清除作用.结果再灌注组骨骼肌病变较单纯缺血时严重,远隔器官肝、肺、肾、胃及脑有弥漫性损伤;红细胞SOD及血清GSH较对照组显著下降(P＜0.05);肝、肺组织匀浆MDA含量显著增多(P＜0.05);灯盏花组病变较对照组明显改善.结论肢体缺血/再灌注不但使再灌注器官本身损伤加重,还可引起远隔多器官损伤;灯盏花作为强抗氧化剂,可明显减轻肢体缺血/再灌注所引起的远隔多器官损伤.     

周围神经缺血再灌注损伤

再灌注损伤是指机体的组织或器官在血液灌注停止或不良,即经历缺血、缺氧后,循环重新建立,血供恢复后给机体带来的损伤。现已在多种器官如小肠、脑、脊髓、肾、胰、骨骼肌等发现再灌注损伤的存在。在神经系统中,中枢神经系统特别是关于脑的缺血再灌注损伤的机制和防治...     

肢体缺血再灌注损伤的研究进展

由于肢体缺血再灌注损伤的机制复杂，目前尚未完全阐明，现将近年来对肢体缺血再灌注损伤的研究进展综述如下。     

骨骼肌缺血再灌注损伤中自由基的产生机制及治疗研究进展

缺血-再灌注损伤(ischaemia-reperfusion iniury,IRI)是指肢体缺血损伤和再灌注损伤的合称,临床中术中应用止血带、骨筋膜室综合征、休克、断肢再植、带血管蒂组织移植等过程骨骼肌均经历缺血再灌注损伤,IRI不仅损伤肢体局部组织,导致骨骼肌的纤维化、挛缩以及肢体的坏死,而且可影响远隔的内脏器官,引起多器官的功能衰竭,危及生命[1],是一种复杂的病理过程,其中自由基介导的损伤起着重要的作用,以下就自由基在骨骼肌IRI中的作用机制及其防治综述如下.     

肢体缺血/再灌注致急性肺损伤的研究现状

肢体缺血,再灌注是临床常见的一种病理生理过程,再灌注损伤不仅存在于局部缺血组织,尚可进一步引发远隔器官肺的损伤,现就肢体缺血/再灌注(limb ischemin-reperfusion,LIR)致急性肺损伤(acute lung injury,ALI)的病理生理机制和防治措施作一综述.     

昼夜节律振荡在器官缺血再灌注损伤中的作用研究进展

昼夜节律存在于人体的中枢和外周器官中, 在生理或病理状态下都发挥着关键的调节作用。缺血再灌注(I/R)损伤是缺血的组织血液循环得到恢复后, 组织再次受到额外的损伤。各器官缺血再灌注损伤发生率高, 严重危害人类健康。研究结果显示昼夜节律振荡对器官缺血再灌注损伤的发生和严重程度有重要影响, 相关信号通路可以作为治疗靶标, 具有潜在应用价值, 但目前未得到全面总结。我们回顾了昼夜节律振荡与各器官缺血再灌注损伤相关研究, 总结了相关信号分子通路, 为器官缺血再灌注损伤的预防及治疗提供新的思路。     

兔后肢缺血再灌注后足背肌腱表面微循环变化

应用活体显微镜技术,观察了兔后肢常温止血带缺血2h(n=8)及5h(n=8)再灌注后最初1h 期间足背肌腱表面微循环动态变化,尤其是白细胞内皮粘附及微血管灌注状况的变化,旨在探讨缺血再灌注损伤的发生机制,从而指导临床治疗。结果表明:①肢体缺血再灌注后缺血组织微静脉内皮上粘附的白细胞数显著增加,而且缺血时间越长,增加越显著。②肢体缺血5h 再灌注后,缺血组织的微循环并不能均匀恢复,部分区域发生“无复流现象”,包括原发性无复流和继发性毛细血管灌注衰竭两种形式。提示:①白细胞内皮粘附参与了缺血再灌注损伤的病理生理过程。②肢体缺血5h 再灌注后发生的局部组织损伤并非皆属缺血再灌注损伤,部分区域可能系单纯缺血性损伤,部分区域则可能属缺血再灌注—继发性缺血损伤。     

Hazards and complications of endoscopic transurethral ureterolithotripsy and lithoextraction and means of prevention

Complications related to ureterolithotomy and ultrasonic ureterolithotripsy performed under the control of visual endoscope were analyzed in 86 ureterolithiasis patients, methods of their prevention discussed. All the aforementioned complications were distributed into three groups: inapplicability of surgery due to anatomic and functional defects of lower and upper urinary tracts, intraoperative, and postoperative complications. The commonest ones were ureteral abruption and perforation, acute pyelonephritis, temporary vesicoureteral reflux. Their control measures were considered as relative methods of treatment: immediate surgical intervention in case of ureteral abruption, renal catheterization in patients with insignificant ureteral perforation or acute pyelonephritis. Adequate ureteroscopy, careful consideration of pro- and contraindications, catheterization of renal pelvis and urinary bladder performed within 2-3 days after the surgery and adequate antibacterial therapy are the most decisive steps in the control of aforementioned complications.     

牙体牙弓颌骨阻力中心及其临床意义

牙体、牙弓及颌骨的阻力中心在正畸矫治力系统中具有重要的意义,也是正畸学领域争论较多的一个问题。Dermaut等研究表明,当力作用于物体阻力中心时,物体将发生平动,否则将发生平动和转动的复合运动。目前,国内外多数学者认为牙体、牙弓及颌骨存在阻力中心,但其位置存在争议。本文就牙体、牙弓及颌骨的阻力中心及其临床意义作一综述。     

Characterisation and differentiation of chondroblastomas and chondromyxoidfibromas - presence and expression of collagen types I and II

AIM: Chondroblastomas and chondromyxoidfiibromas are rare benign skeletal neoplasms with reported overlapping histology. Aim of this study was to analyse the biochemical composition of the matrix of these tumour entities in order to further characterise the cellular phenotypes of these neoplasms using typical cell biological marker genes. METHODS: The matrix compositions of chondroblastomas and chondromyxoidfibromas were analyzed by HE-histology, histochemistry, and immunolocalization techniques. Cellular gene expression patterns were detected by mRNA in situ hybridization. RESULTS: Chondroblastomas are rich in collagen type I and show foci of an osteoid-like matrix, whereas collagen type II as a typical marker of chondrocytic differentiation was not detected in any of the specimens. Chondromyxoidfiibromas had foci of chondroid appearance with chondroblastic cellular differentiation characterised by collagen type II expression. CONCLUSION: These results characterise chondroblastomas and chondromyxoidfiibromas as skeletal neoplasms that have a different biology and which can be distinguished by matrix protein expression products: collagen type II, the typical marker of chondroblast differentiation, could only be detected in chondromyxoidfibromas, but not in chondroblastomas. Thus, both neoplasms are clearly different on the cell biological level.     

Histochemical and contractile properties of striated muscles of urethra and levator ani of dogs and sheep

AIMS: To understand their possible importance in long- and short-term control of continence, some properties of the striated muscles of the urethra and pelvic floor (levator ani) of dogs and sheep were investigated, especially fiber types and contractile characteristics. MATERIALS AND METHODS: Striated muscles of urethra and levator ani of 29 male and 6 female dogs and 11 male and 6 female sheep were removed and cut into strips. Some strips were frozen and stained for ATPase at pH 9.4 and 4.3 for fiber typing; others were set up in an organ bath to study contractile responses to nerve stimulation. RESULTS: All muscles contained both type I (slow) and type II fibers, ranging from 97% type II in female greyhound urethra to 60% in female sheep levator ani. For each muscle, there were fewer type II muscles in sheep than in dog. The diameters of the urethral fibers were about 60% of the levator ani in dogs and 34% in sheep. Contraction of the urethral muscle was faster than for levator ani and declined to about 80% of the peak, 500 msec after the beginning of stimulation at 20 Hz. The levator ani contraction rose to a steady level as long as stimulation continued. CONCLUSIONS: Both the levator ani and urethral striated muscles contain slow and fast fiber types. The levator ani muscles are capable of sustained contraction with rapid onset which will produce long-term closure of the urethra. The circular urethral muscle contraction was faster but less well maintained.     

Incorporation and release of85Sr and14C-proline-hydroxyproline in mineral and collagen of bone and incisor teeth of growing rats

The extent to which exchange and reutilization processes of mineral tracers affect skeletal mineral accretion and resorption measurements was evaluated by comparing the rates of appearance and disappearance of⁸⁵Sr and¹⁴C-proline-hydroxyproline in bones and teeth in growing rats for 12 days following simultaneous parenteral injection of these tracers. Expressions for the relative rates of collagen synthesis and breakdown, which unlike mineral metabolism are considered not to be complicated by exchange phenomena, were based on¹⁴C-proline conversion to¹⁴C-hydroxyproline; the specific activity of the latter was determined. Both the mineral and the collagen specific activities reflected the rates and patterns of growth of the samples assayed; rapid growth and a short interval of time between formation and resorption of tissue in themetaphyseal bone which contains the cartilagineous growth plate, slow growth and an interval of time between formation and resorption of tissue indiaphyseal bone and incisor teeth which is longer than the 12 days of the experiment. However, in metaphyseal bone the specific activity collagen/mineral ratio dropped by one half during the 4–12 day interval in contrast to diaphyseal bone and incisor teeth in which no change in this ratio was observed during this period of time. The data indicate that collagen in the metaphyseal growth zone is removed by resorption before it has become fully mineralized, and that exchange is a relatively unimportant factor in the long term kinetics of bone mineral.

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Zusammenfassung Das Ausmaß, bis zu welchem Austausch- und Wiederverwendungsprozesse der mineralen Tracer die Messungen des mineralen Skelett-Auf- und Abbaues beeinflussen können, wurde ausgewertet; zu diesem Zweck wurde die Geschwindigkeit des Auftretens und Verschwindens von⁸⁵Sr und von¹⁴C-Prolin-Hydroxyprolin in Knochen und Zähnen von wachsenden Ratten während der 12 auf die simultane parenterale Injektion dieser Tracer folgenden Tage verglichen.Der Ausdruck für die relative Geschwindigkeit des Kollagen-Auf- und Abbaues, bei welchem im Gegensatz zum Mineralmetabolismus kein Mitwirken des Austauschphänomens vermutet wird, basiert auf der Umwandlung von¹⁴C-Prolin zu¹⁴C-Hydroxyprolin; die spezifische Aktivität des letzteren wurde bestimmt.Aus der spezifischen Aktivität des Minerals sowie jener des Kollagens konnten die Geschwindigkeit und die Art des Wachstums der untersuchten Proben ersehen werden, d.h.schnelles Wachstum und ein kurzes Zeitintervall zwischen Bildung und Resorption des Gewebes imKnochen der Metaphyse, die auch die knorpelige Wachstumsplatte enthält, und andererseitslangsames Wachstum und längeres Zeitintervall (länger als die 12 Tage des Experimentes) zwischen Bildung und Resorption des Gewebes imKnochen der Diaphyse und in den Schneidezähnen. Immerhin fiel die spezifische Aktivität des Kollagen/Mineral-Anteils im Knochen der Metaphyse während dem 4–12tägigen Zeitintervall auf die Hälfte, im Gegensatz zum Knochen der Diaphyse und der Schneidezähne, bei welchen während dieser Zeitspanne kein Unterschied in diesem Verhältnis beobachtet wurde.Diese Ergebnisse zeigen, daß Kollagen in der Wachstumszone der Metaphyse durch Resorption verschwindet, bevor es ganz mineralisiert ist, und daß der Austausch ein relativ unwichtiger Faktor in der Kinetik auf lange Sicht des Knochenminerals ist.