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排序方式: 共有525条查询结果,搜索用时 15 毫秒
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W. Ptzl P. Kümpers T. Szuwart T. Filler B. Marquardt J. Steinbeck 《Journal of orthopaedic research》2004,22(6):1345-1350
Despite widespread use of radiofrequency (RF)-shrinkage, there have been no studies on the influence of RF-energy on neural elements of collagenous tissue. The purpose of this study was to examine the effect of RF-shrinkage on neural structures of capsuloligamentous tissue and the recovery of neural elements under different postoperative treatment protocols. One patellar tendon of 46 New-Zealand-White rabbits was shrunk. Six rabbits were sacrificed immediately postoperative. Twenty rabbits were not immobilized, 10 were immobilized for 3 and 10 were immobilized for 6 weeks. A monoclonal antibody, specific against a neurofilament protein, was used to detect nerves and neural structures. Staining pattern of nerve fibres was significantly altered immediately postoperative. After 3 weeks the number of nerve fibres and bundles decreased significantly in immobilized and non-immobilized limbs. The loss of nerve fibres was significantly less in immobilized limbs. At 6 weeks the number of neural elements in immobilized limbs increased to the level of untreated control tissue. In non-immobilized limbs we found no recovery of neural elements 9 weeks postoperatively. At this time the number of nerve fibres and bundles was still significantly less compared to the untreated control limbs. RF-shrinkage causes significant alteration of neural elements. Under immobilization nerve fibres and bundles reach the level of normal untreated tissue. Careful rehabilitation is important after RF-shrinkage. Not only for biomechanical reasons, but also to allow the neural elements to recover, thermally modified tissue should be protected from normal physiologic loads. 相似文献
4.
双极射频电热固缩治疗前交叉韧带松弛临床研究 总被引:5,自引:0,他引:5
目的:对15例前交叉韧带双极射频电热固缩治疗进行回顾性研究,评估其临床疗效。方法:从2000年1月至2005年1月采用双极射频对16例前交叉韧带松弛的患者进行电热固缩治疗。完整随访者15例,男性11例,女性4例,平均年龄29岁。12例前交叉韧带部分损伤,3例为自体绳肌重建术后。电热射频设备输出功率为284W,组织内作用温度为65℃。术后患者采用支具制动,康复计划与前交叉韧带重建术后基本相同。结果:随访时间平均15·6个月(4~25个月)。Lysholm评分,术前74·27±5·51分(66~84分),术后3个月89·6±7·11分(72~99分),两者相比有显著性差异(P<0·01);术后最终评分83·33±11·81分(56~95分),虽仍显著高于术前评分(P<0·05),但与术后3个月比较有所降低。KT-1000测量结果,术前两侧胫骨前移差值为5·47mm±1·61mm(3·5mm~10mm),术后3个月为2·67mm±1·35mm(2~7mm),与术前测量值对比存在显著性差异(P<0·01);最终测量结果为3·8mm±1·96mm(2~9mm),虽仍显著低于术前测量值(P<0·05),但较术后3个月有所增加。所有患者均未出现明显的术后并发症。2例患者(13·3%)术后失效,接受了二期重建手术。结论:电热固缩治疗前交叉韧带松弛可获得较好的短期主、客观疗效,但长期随访疗效有所下降。建议慎重选择手术适应症。 相似文献
5.
J.H. van Dieen M. Creemers I. Draisma H.M. Toussaint I. Kingma 《Clinical biomechanics (Bristol, Avon)》1994,9(6):367-374
The assumed advantages of the so-called leg-lifting technique over the back-lifting technique are still the subject of much debate. The present study was aimed at studying the consequences of performing both lifting techniques on net lumbar moments and spinal shrinkage. Furthermore, the relation between age and spinal shrinkage was studied. Five subjects approximately 40 years old and six subjects 20 years old performed six 5-min bouts of repetitive lifting using each technique on a separate day. Net lumbar moments were calculated using a two-dimensional dynamic linked segment model. Spinal shrinkage was measured at T12 and at the head after each bout of lifting and every 5 min during 1 h preceding the lifting bouts. The peak moments were marginally but significantly higher in the leg-lift. No differences in mean moments and shrinkage between lifting techniques were found. The shrinkage after the back-lift was more pronounced in the older subjects and a similar tendency was found after the leg-lift. The creep rate, i.e. the rate at which the shrinkage approaches its equilibrium was higher in the older subjects. No clear relations of anthropometrical variables and net moments with shrinkage was found. The common advice of using a leg-lift rather than a back-lift was not supported by the present study. Both the mechanical load on the low back (net moments) and the resulting shrinkage show considerable interindividual variation, the causes of which need further elucidation.
The leg-lifting technique is still widely advocated, thought its merits from a biomechanical point of view have been questioned. In this study spinal shrinkage and lumbar moments calculated by means of a dynamic linked segment model are used to compare the leg-lift to the more commonly used back-lift. 相似文献
6.
George Thabit III MD 《Operative Techniques in Sports Medicine》1998,6(3):157-160
The Holmium:YAG (Ho:YAG) laser is the arthroscopic laser of choice. The arthroscopic surgeon can ablate, coagulate, or shrink periarticular soft tissues by manipulating Ho:YAG laser power settings. The ability to ablate soft tissue in a hemostatic fashion greatly facilitates the treatment of labral tear, synovitis, subacromial arch decompression, and distal clavicle arthritis. The nonablative application of Ho:YAG laser energy has been used successfully to treat glenohumeral instability. The laser-assisted capsular shift (LACS) procedure, in conjunction with standard labral repair techniques, successfully treats unidirectional and multidirectional shoulder instability Neuromuscular rehabilitation is accelerated. Excellent clinical results may be achieved with appropriate surgical technique and postoperative rehabilitation. 相似文献
7.
Cation channels,cell volume and the death of an erythrocyte 总被引:8,自引:0,他引:8
Lang F Lang KS Wieder T Myssina S Birka C Lang PA Kaiser S Kempe D Duranton C Huber SM 《Pflügers Archiv : European journal of physiology》2003,447(2):121-125
Similar to a variety of nucleated cells, human erythrocytes activate a non-selective cation channel upon osmotic cell shrinkage. Further stimuli of channel activation include oxidative stress, energy depletion and extracellular removal of Cl–. The channel is permeable to Ca2+ and opening of the channel increases cytosolic [Ca2+]. Intriguing evidence points to a role of this channel in the elimination of erythrocytes by apoptosis. Ca2+ entering through the cation channel stimulates a scramblase, leading to breakdown of cell membrane phosphatidylserine asymmetry, and stimulates Ca2+-sensitive K+ channels, thus leading to KCl loss and (further) cell shrinkage. The breakdown of phosphatidylserine asymmetry is evidenced by annexin binding, a typical feature of apoptotic cells. The effects of osmotic shock, oxidative stress and energy depletion on annexin binding are mimicked by the Ca2+ ionophore ionomycin (1 µM) and blunted in the nominal absence of extracellular Ca2+. Nevertheless, the residual annexin binding points to additional mechanisms involved in the triggering of the scramblase. The exposure of phosphatidylserine at the extracellular face of the cell membrane stimulates phagocytes to engulf the apoptotic erythrocytes. Thus, sustained activation of the cation channels eventually leads to clearance of affected erythrocytes from peripheral blood. Susceptibility to annexin binding is enhanced in several genetic disorders affecting erythrocyte function, such as thalassaemia, sickle-cell disease and glucose-6-phosphate dehydrogenase deficiency. The enhanced vulnerability presumably contributes to the shortened life span of the affected erythrocytes. Beyond their role in the limitation of erythrocyte survival, cation channels may contribute to the triggering of apoptosis in nucleated cells exposed to osmotic shock and/or oxidative stress. 相似文献
8.
We present a new wavelet-based method for single trial analysis of transient and time variant event-related potentials (ERPs). Expecting more accurate filter settings than achieved by other techniques (low-pass filter, a posteriori Wiener filter, time invariant wavelet filter), ERPs were initially balanced in time. By simulation, better filter performance could be established for test signals contaminated with either white noise or isospectral noise. To provide an example of real application, the method was applied to limbic P300 potentials (MTL-P300). As a result, variance of single trial MTL-P300s decreased, without restricting the corresponding mean. The proposed method can be regarded as an alternative for single-trial ERP analysis. 相似文献
9.
Blastocoele collapse by micropipetting prior to vitrification gives excellent survival and pregnancy outcomes for human day 5 and 6 expanded blastocysts 总被引:10,自引:0,他引:10
Hiraoka K Hiraoka K Kinutani M Kinutani K 《Human reproduction (Oxford, England)》2004,19(12):2884-2888
BACKGROUND: Manual puncture of the trophectoderm of human blastocysts with a needle before vitrification increases their survival rate, but the embryos take a long time to re-expand. This study examined whether causing human blastocysts to collapse by manual pipetting before vitrification would allow more rapid re-expansion and improve pregnancy rates. METHODS: After embryo transfer in IVF cycles, surplus embryos that developed to the expanded blastocyst stage were placed in cryoprotectant and then artificially shrunk by mechanical pipetting with a fine hand-drawn glass pipette slightly smaller in diameter than the blastocyst. The shrunken embryos were placed in a small volume of vitrification solution and plunged into liquid nitrogen on a cryotop. The blastocysts were thawed by warming and then dilution in 1 mol/l sucrose. RESULTS: Of 49 expanded vitrified blastocysts, 48 (98%) re-expanded within 3 h after warming. Following transfer (48 blastocysts in 28 cycles), 14 women (50%) became clinically pregnant, and the implantation rate was 33% (16/48). Eight healthy babies have been born in six deliveries, and the other eight pregnancies are ongoing. To date, there have been no spontaneous abortions. CONCLUSIONS: The results suggest that artificial shrinkage with pipetting is a simple and effective technique to assist successful cryopreservation of expanded blastocysts by vitrification. 相似文献
10.
Zhiguo Ma Yue Li Zhensheng Cao Shaoqiang Zhang Shengjun Hou Jilin Liu Xin Ruan 《Materials》2022,15(10)
For the Honghe Bridge project located in Yunnan Province, Southwest China, a steel/ultrahigh-performance concrete (UHPC) composite deck is used in the suspension bridge with a 700 m main span, and the steel stud connectors are used in the 50 mm–thick UHPC layer. To investigate the shrinkage behavior of UHPC and the relevant influence, the in situ time-dependent strain is measured continuously, and within the 20-day curing time, the material behavior is summarized based on test results. This paper proposes a prediction model for UHPC shrinkage which is refined from the widely used B3 model for normal concrete material, and the parameter values are modified and optimized by experimental comparison. Combining the numerical model and the finite element analysis model of the composite deck, the detailed mechanical state in structural parts is studied. For the practical construction, the simulation results indicate that the small thickness of UHPC above the stud and weak bond strength can influence the eventual structural performance greatly. In the discussion of stress distribution at different locations of the deck, the potential crack on the edge and the corner of the UHPC–steel interface and the mechanical damage on the stud connector around are also indicated. 相似文献