同种异体肌腱移植

随着科学技术的发展 ,对异体组织储备方式、保存方法的改进以及检测手段的先进和严密 ,使异体肌腱在临床上取得与自体肌腱移植近似的效果 ;并具有容易获取、不增加切口等优点。目前对异体肌腱的临床应用和实验研究日益增多 ,均取得了重要的经验。肌腱组织是一种致密的结缔组织 ,由腱细胞、腱基质及胶原纤维束组成。胶原纤维束的排列有特定的轴向、长度和密度。腱细胞具有分泌基质及胶原的功能[1] 。大量研究表明 ,无论是异体还是自体肌腱在游离移植时都作为一个整体存活 ,并通过修复过程重建。但异体肌腱移植后的修复过程要比自体肌腱复杂 ,…     

冷冻干燥同种异体肌腱移植修复肌腱缺损

目的探讨应用异体肌腱移植修复手、足部肌腱缺损的疗效.方法手术切除缺损部位的瘢痕,移植异体肌腱,修复重建肌腱及其功能.结果本组12例,27根肌腱,术后均未见有急性排斥反应,半年后行肌腱松解术时与自体肌腱移植无明显差异.修复重建的肌腱功能均有不同程度的恢复.结论异体肌腱与残存肌腱愈合,功能恢复良好.     

培养处理与冷冻保存同种异体肌腱的临床研究

目的建立经培养处理与冷冻保存的同种异体肌腱库,该腱临床应用已获得初步成功。方法将新鲜人体肌腱在含脱氧鸟苷的培养液中培养后,置入冷冻保护剂中,经超深低温无创冻存。１９９６年８月至１９９８年１２月,临床对１２例患者应用３０根同种异体肌腱。术前经快速复温及洗涤后将复苏肌腱作腱细胞活力测定、组织学检测。结果经培养处理与冻存的异体肌腱细胞活力为（７０．５±４．５）％（ｘ±ｓｘ,下同）。复苏后冷冻处理肌腱的组织学结果,与新鲜异体肌腱无显著性差异。１２例患者术后屈指功能良好,初步观察不必作粘连松解术。结论（１）脱氧鸟苷培养及无创冻存处理的人体肌腱,复苏后仍保存７０．５％的活力,是“活体”肌腱。（２）临床应用获得初步成功,粘连发生较少     

同种异体肌腱移植的研究进展

自体肌腱移植,虽然腱再生都能获得成功,但是供腱来源有限．又会给供区带来不同程度的损伤和功能障碍,人工肌腱虽已有临床应用的报道,但其材料和与受体肌腱愈合等问题,尚未完全解决。由此近十几年来．人们在同种异体肌腱移植方面进行了诸多研究工作．不断取得新的进展。目前依然多在降低异体肌腱移植后的免疫排斥和解决腱再生发生粘连这两个问题上进行研究中。现将其研究进展综述如下。     

同种异体肌腱修复肌腱缺损的远期疗效观察

目的总结同种异体肌腱修复肌腱缺损的远期临床疗效。方法 1996年10月-1999年9月,采用经脱氧鸟苷培养冷冻保存与超深低温处理的同种异体肌腱移植修复肌腱缺损24例。男19例,女5例;年龄12～46岁,平均25.9岁。2～5指指总伸肌腱缺损7例,示指伸肌腱缺损7例;2～5指指深屈肌腱缺损3例,环指指深屈肌腱缺损1例;2～5趾趾长伸肌腱缺损3例;长伸肌腱缺损2例;肩胛带离断再植术后肩内收不能1例。肌腱缺损范围5～15 cm。受伤至手术时间为2 h～3个月,平均1.3个月。结果术后切口均Ⅰ期愈合,无深部感染及传染性疾病发生。患者均获随访,随访时间10～12年,平均10.8年。与对侧相同或相近关节比较,术后10年随访时1例4条移植肌腱有6～10°屈曲功能丢失,术后10.6年行屈肌腱松解,术中见同种异体肌腱色泽、弹性正常,直径较原肌腱减少约1/3,有轻度到中度粘连,松解术后功能改善明显;余患者关节伸屈功能良好。根据中华手外科学会手功能评价标准评定临床效果,获优12例,良6例,差6例,优良率达75%。结论脱氧鸟苷培养冷冻处理与超深低温处理的同种异体肌腱均可安全用于临床,其修复肌腱缺损的远期效果较好。     

VEGF抗体对兔同种异体肌腱移植作用的实验研究

目的 探讨VEGF抗体在异体肌腱移植愈合过程中的作用.方法 将深低温冷冻的同种异体肌腱移植修复新西兰大白兔跟腱缺损,实验组腱周局部滴加VEGF多克隆抗体,对照组滴加生理盐水.术后1、2、4、8周四个时相点处死动物,标本进行大体观察、组织学观察、胶原含量测定及生物力学测试.结果 实验组肌腱粘连等级评分较对照组明显改善,组织学观察可见术后早期实验组较对照组炎性细胞及新生毛细血管数量少,胶原含量差异不明显,但术后8周实验组胶原纤维排列更规则.生物力学测试显示实验组同对照组断裂载荷无显著差异.结论 局部应用VEGF抗体,可以减轻移植肌腱粘连,而对移植肌腱的愈合无明显影响.     

多聚甲醛处理异体肌腱移植的实验研究

目前常用低温冷冻、冷冻干燥及化学处理等方法处理肌腱以降低其抗原性。比较公认的降低肌腱抗原性的机理是：经特殊处理肌腱的方法，损伤了肌腱细胞成分或／和改变了细胞膜上组织相容性抗原结构。本实验采用多聚甲醛（ｐａｒａｆｏｒ－ｍａｌｄｅｈｙｄｅ，ＰＦＡ）处理肌...     

透明质酸钠在同种异体肌腱移植中的临床应用

目的 探讨透明质酸钠（Sodium hyaluronate Product,SHP)在同种异体肌腱移植后防止肌腱粘连的作用。方法 对23例37指屈肌腱损伤，行异体屈肌腱移植后，均匀涂SHP2mL-4mL，修复腱鞘，术后72小时开始手指功能锻炼。另选20例35指屈肌腱损伤，用同样方法治疗，术中不用SHP作对照。结果 两组经过平均1年8个月的随访，按TAM（Total active movement,TAM)标准评定疗效，SHP组37指，疗效优良33指，优良率89．2％，显高于对照组的62．9％（P＜0．05）。结论 透明质酸钠能防止或减轻异体肌腱移植后肌腱粘连，促进肌腱愈合。     

人同种异体肌腱的实验研究及临床应用

[目的]在无水甘油保存液中保存人同种异体肌腱,并做人肌腱移植,评估人同种异体肌腱保存的可行性.[方法]将人同种异体肌腱随机分为2组,即生理盐水组、无水甘油组,各组在12个月进行细菌学检查;将人同种异体肌腱随机分为2组,即新鲜肌腱对照组、无水甘油组肌腱,保存12个月后行生物力学测定;无水甘油组肌腱保存12个月后复水修复人的肌腱缺损.[结果]12个月内无水甘油保存液无细菌生长,保存12个月后进行肌腱的生物力学测试.无水甘油肌腱组:最大拉伸力均值367.2 N,标准差141.6;拉伸刚度107.1 N/mm,标准差31.9.新鲜肌腱组:最大拉伸力均值418.0 N,标准差114.6;拉伸刚度86.0 N/mm,标准差24.6;无水甘油组肌腱修复肌腱缺损22例,28条肌腱,随访7个月～7.8年,平均5.8年,TAM法进行功能测定:优良率72.7％,可13.6％,差13.6％.[结论]无水甘油保存液具有抑制细菌作用,无细菌生长;在无水甘油保存液中常温对肌腱进行保存,在12个月内,无水甘油组肌腱和新鲜肌腱在生物力学上无统计学差异;在无水甘油保存液保存的肌腱可以替代自体肌腱用于肌腱移植,并取得了比较满意的临床效果.     

同种异体肌腱移植在手部创伤中的应用

随着同种异体肌腱移植免疫学研究的进展，异体肌腱移植逐步得到重视并广泛应用于临床。我院自2004年10月～2006年10月，应用经深低温冷冻的异体肌腱，为24例28条肌腱缺损患者进行了移植手术，收到良好疗效，现报道如下。     

A comparison of the inhibitory effects of four volatile anaesthetics on the metabolism of chlorzoxazone, a substrate for CYP2E1, in rabbits

Background: Halothane inhibits in vitro and in vivo activity of cytochrome P-450 (CYP) 2E1. There are several fluorinated volatile anaesthetics besides halothane, and most of them are defluorinated by CYP2E1. It is unclear whether other fluorinated anaesthetics inhibit the in vivo activity of CYP2E1.
Methods: We compared the inhibitory effects of therapeutic concentrations of four inhalational anaesthetics, halothane, enflurane, isoflurane, and sevoflurane, on chlorzoxazone metabolism in rabbits receiving artificial ventilation.
Results: All four inhalational anaesthetics decreased arterial blood pressure and increased plasma chlorzoxazone concentration. However, no significant differences in the plasma chlorzoxazone concentration were found between the four anaesthetics. The estimated chlorzoxazone clearance increased after beginning inhalation with all four agents, but no significant difference in clearance was noted between agents.
Conclusions: At therapeutic concentrations, the in vivo inhibitory effect on chlorzoxazone metabolism was similar for all four inhalational anaesthetics examined, even though their chemical characteristics and extent of hepatic metabolism differ considerably.     

Is the recovery profile of mivacurium independent of the rate of decay of its plasma concentration in patients with normal plasma cholinesterase activity?

Background: The duration of action of muscle relaxants is poorly correlated to the rate of decay of their plasma concentration. The plasma concentration of mivacurium may rapidly decrease below its active concentration because of the extensive hydrolysis of mivacurium. By inflating a tourniquet on one upper limb for 3 min after the administration of atracurium, mivacurium or vecuronium, we studied the influence of the initial decline of their plasma concentration on their effect. Methods: In 50 patients anaesthetised with thiopental, isoflurane and fentanyl, the effect of bolus doses of 0.15 or 0.25 mg . kg^?1 mivacurium (MIV 15, MIV 25), 0.3 or 0.5 mg . kg^?1 atracurium (ATR 30, ATR 50) and 0.06 or 0.1 mg . kg^?1 vecuronium (VEC 06, VEC 10) were measured on both arms (evoked response of the adductor pollicis to train-of-four stimulation every 12 s), a tourniquet being applied on one arm just before and during 3 min after the muscle relaxant bolus. Results: Tourniquet inflation of 3 min almost abolished the neuromuscular effect of mivacurium. In the vecuronium groups and in the ATR 50 group, tourniquet inflation did not modify the maximum degree of depression of the twitch response. Also, the duration of action of vecuronium was unaffected by the tourniquet. In the ATR 30 group, times to return of the twitch response to 25% (duration 25%) and 75% (duration 75%) of control response were significantly shorter in the cuffed arm, 23 min vs 27 min, and 41 min vs 45 min, respectively. In the ATR 50 group, only duration 25% was significantly shorter in the cuffed arm (41 min vs 45 min). Conclusion: The results suggest that the rate of decline of the plasma concentration of mivacurium is so rapid, that a very low and almost clinically ineffective concentration is present as soon as 3 min after its administration. The results also indicate that the recovery from a mivacurium-induced neuromuscular blockade is not influenced by the rate of decay of its plasma concentration in patients with genotypically normal plasma cholinesterase.     

Membranes in Artificial Organs

Abstract: Membrane processes play a pivotal and enabling role in modern replacement therapy for acute and chronic organ failure and in the management of immunologic diseases. In fact, virtually all contemporary extracorporeal blood purification methods employ membrane devices, and the next generation of artificial organs and tissue engineering therapies are almost certain to be similarly grounded in membrane technology. In this short essay, we comment on the similarities and differences among synthetic membranes and their natural counterparts and also provide a critical overview of the demographics and technology of hemodialysis, hemofiltration, apheresis, oxygenation, and emerging membrane technologies and applications.     

Intrathecal administration of sameridine to patients subjected to arthroscopic knee joint surgery

Background: Sameridine, a new substance with both local anesthetic and opioid effects, was administered intrathecally for the first time to humans, i. e. in patients subjected to arthroscopic knee joint surgery.
Method: A dose-escalating (10, 15, 20 and 25 mg), open study was performed in 33 patients. Only two patients were included in the 25 mg group.
Results: Sameridine provided good quality of surgical anesthesia in all patients except those receiving 10 mg. The maximum level of sensory block, Th5–Th7, was reached within 30 min with a median duration of 3.6–3.9 h. The motor block was more profound with increasing dose, but never lasted longer than the sensory block. The influence on heart rate and blood pressure was minor and atropine and ephedrine were needed in four patients. No clinically significant ECG-changes were detected and no arrhythmias were recorded. Oxygen saturation and respiratory rate did not decrease in a clinically significant way and were not affected by concomitant morphine given i. v. postoperatively. There were few side-effects, the most frequent being mild pruritus (10/33).
Conclusion: Sameridine provided clinically adequate anesthesia for the patients receiving the doses of 15, 20 and 25 mg. Further studies are needed to evaluate the substance and it is of great interest to clinically investigate the opioid component with respect to postoperative analgesia.     

Dilemma of Membrane Biocompatibility and Reuse

Abstract: Numerous articles have been published on the multiple use of dialyzers and on the effect of different reprocessing chemicals and techniques on the dialyzer biocompatibility and performance. The results often appear contradictory, especially those comparing standard biocompatibility parameters. Despite this confusion, a discerning review of the published works allows certain limited conclusions to be drawn. Reprocessing of used hemodialyzers changes the biocompatibility profile of a dialyzer as defined by the parameters complement activation. leukopenia, and cytokine release. The effect of reprocessing depends on the chemicals and reprocessing technique applied and also on the type of membrane polymer being subjected to the reprocessing procedure. Reports of pyrogenic reactions indicate that the flux of the membrane also influences how suitable it is for safe reuse. An increased risk of allergic and pyrogenic reactions appears to be associated with dialyzer reuse. Furthermore, there has been a lack of investigations into the immunologic effect of the layer of adsorbed and chemically altered proteins that remains on the inner surface of reprocessed dialyzers. We conclude that the clinical benefit of dialyzer reuse cannot be generally accepted from a biocompatibility point of view.     

Anesthésie du patient épileptique

Although surgery of brain tumors and epilepsy are restricted to few specialized centers, anaesthesia for a patient with epilepsy is commonly encountered. Surgical treatments of epilepsy are currently soaring due to the lack of significant progress about effectiveness of antiepileptic drugs (AEDs). Theoretical principles for the anaesthesiologist are quite complex, involving interactions between physiological and pharmacological anaesthesia and AEDs, such as enzyme induction with the first generation molecules mainly (phenytoin, carbamazepin, phenobarbital). The latest generation AEDs (levetiracetam, lamotrigine, gabapentin, oxcarbazepin, vigabatrin, lacosamide...) are better tolerated and induce fewer drug interactions. Practically, the risk of severe perioperative complications is low, provided that the administration of AEDs is kept as close as possible to its usual dosage, and that metabolic disturbances are prevented. The main anaesthetic drugs to avoid are alfentanil, remifentanil and sevoflurane, although their contraindication are only relative, since the clinical benefit might be clear and the doses should remain moderate.     

The analgesic effect of racemic ketamine in patients with chronic ischemic pain due to lower extremity arteriosclerosis obliterans

Background : Ketamine in sub-dissociative doses has been shown to have analgesic and phantom-Limb pain, where conventional treatment has often failed. Chronic ischemic pain due to lower extremity arteriosclerosis obliterans often responds poorly to analgesics, and the pain-generating mechanisms are not well understood.
Methods : Eight patients with rest pain in the lower extremity due to arteriosclerosis obliterans were given sub-dissociative doses of 0.15, 0.30, or 0.45 mg/kg racemic ketamine and morphine 10 mg as a 5-min infusion on four separate days in a cross-over, double-blind, randomised protocol. Plasma levels of (S)- and (R)-ketamine and their nor-metabolites were analysed with an enantioselective high-performance liquid chromatography (HPLC) method. Pain levels were evaluated with a visual analogue scale (VAS).
Results : Individual pain levels were highly variable during and after all the infusions but the pooled pain levels showed a dose-dependent analgesic effect of ketamine with a transient but complete pain relief in all patients at the highest dose (0.45 mg/ kg). Side-effects, mainly disturbed cognition and perception, were pronounced and dose-dependent. Morphine 10 mg had an analgesic peak at 20 min and 5/8 patients had complete pain relief. The remaining 3 patients also had high baseline pain scores, indicating a higher analgesic potency for the 0.30 and 0.45 mg/ kg ketamine doses than for morphine 10 mg.
Conclusion : We have demonstrated a potent dose-dependent analgesic effect of racemic ketamine in clinical ischemic pain. Due to a narrow therapeutic window, this analgesic effect is probably best utilised in combination with other analgesics.     

Intravenous endotoxin does not increase tissue extravasation of albumin in rats

Background : It is unclear whether activation of the inducible nitric oxide synthase (iNOS) increases or decreases the extravasation of plasma.
Methods : Chloralose anaesthetised male Wistar rats received E. coli lipopolysacharide (LPS), 3 mg kg^-1 i.v., or the corresponding volume of saline, 3 or 5 h before the end of the experiment. Mean arterial pressure (MAP) and heart rate (HR) were recorded. Tissue clearance of radio-labelled albumin, during the last 2 h of each experiment, was determined by a double-isotope method. In separate animals, the serum concentration of nitrite and nitrate was determined, 5 h after LPS or the solvent.
Main Results : LPS initially decreased MAP and lastingly increased HR. In the 3-h LPS animals (n=8), tissue plasma clearance was lower in the heart and calf muscle and increased only in diaphragm, compared to corresponding control animals (n=8). In the 5-h LPS rats, clearance was lowered (n=8) in the entire gastrointestinal tract and in testes, compared to controls (n=8). The serum nitrite/nitrate concentration was higher in animals given LPS (n=6) than in controls (n=6).
Conclusion : After LPS, tissue clearance of albumin was not increased in any major tissue, in spite of increased serum levels of NO end products. Apparently, after activation of iNOS, the augmented release of NO is not necessarily associated with increased albumin extravasation.