NGD及NRF对大鼠坐骨神经缺损修复的电生理学检测

目的 :观察神经生长液 ( NGD)及神经再生素 ( NRF)修复大鼠坐骨神经缺损的效果。方法 :用生理盐水( NS)、NRF桥接以及 NRF桥接 +口服 NGD修复大鼠坐骨神经缺损 ,术后 12周检测大鼠坐骨神经干动作电位传导速度及肌电图。结果 :行为方面 NGD+ NRF组比 NS组恢复早 ,NS组、NRF组、NRF+ NGD组神经干动作电位传导速度的平均值分别为 5 .72 0 m/ s、16 .5 14 m/ s、2 1.310 m/ s。NS组与 NGD+ NRF组的神经干动作电位传导速度经统计学分析有显著性差异 ( P<0 .0 1)。NGD+ NRF组与 NS组的肌电图比较 ,前者的潜伏期短、峰谷值大、运动神经传导速度快。结论 :NGD+ NRF具有良好促进神经再生作用     

Repair and reconstruction of peripheral nerve injuries

Axonal regeneration after transection is a complex biological process. It is not merely a process of tissue repair, but rather of cellular repair of a large number of nerve cells. Regeneration involves restoration of the original morphology of each single cell, rather than proliferation. Techniques in microneurosurgical reconstruction of peripheral nerve injuries have improved over the last two decades, with subsequent improvement in functional results. Nerve autografts are now routinely used to guide the regrowth of the proximal nerves to distal nerve segments. However, the limited source of expendable cutaneous nerves restricts the use of nerve grafting techniques and is associated with significant morbidity. With extensive injuries there is an insufficient quantity of nerve autograft material to facilitate optimal repair. In future, the use of artificial conduits or nerve allografts could provide a limitless source of material to reconstruct otherwise irreparable traumatic nerve injuries. Establishment of appropriate strategies to suppress host-immune reaction or donor antigenicity would facilitate clinical allogeneic nerve transplantation. Guest lecture presented at the 69th Annual Meeting of the Japanese Orthopaedic Association in Tokyo on April 13, 1996.     

Effect of experimental alcoholism on structure and regenerative powers of the neonatal myocardium and liver of the next generation of newborn rats

Department of Pathological Anatomy, I. N. Ul'yanov Chuvash University, Nizhnii Novgorod. (Presented by Academician of the Academy of Medical Sciences of the USSR D. S. Sarkisov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 112, No. 11, pp. 552–553, November, 1991.     

Guided bone regeneration for immediate non‐submerged implant placement using bioabsorbable materials in Beagle dogs

The aim of the present study was to evaluate the combined application of different bioabsorbable materials for healing of residual peri‐implant defects after placement of non‐submerged implants into fresh extraction sockets. Second and third mandibular premolars were extracted from 10 Beagle dogs, the coronal part of the distal sockets were surgically enlarged and this was followed by immediate placement of specially designed hollow‐screw non‐submerged dental implants. For each animal, the coronal peri‐implant defects were further treated with one of the 4 following procedures: 1) no treatment, control site: 2) grafting with porous hydroxyapatite (HA); 3) collagen membrane tightly secured around the implant and over the defect and 4) grafting with HA covered with a collagen membrane. After 16 weeks of healing, specimens were removed from the mandibule and prepared for a histomorphometric evaluation. The bone-to-implant contact length (BIC) was measured and compared amongst the different treatment modalities. In the defect area, the irregular bone regeneration was similar between all the treatment procedures ( P >0.10). In the sites covered with a collagen membrane alone, the total BIC (47%) was greater than in control sites (28.7%. P <0.05) or sites grafted with HA (22.2%, P <0.02). Total BIC in sites treated with the HA‐membrane combination (43%) was only significantly different from sites treated with HA ( P <0.10). It is concluded that the use of bioabsorbable materials results in a limited increase of osseointegration when used in conjunction with immediate placement of non-submerged implants, although the principle of the one stage surgical approach can be maintained.     

Glycosaminoglycan Supplementation Promotes Nerve Regeneration and Muscle Reinnervation

This study shows that treatment of rats with exogenous glycosaminoglycans stimulates peripheral nerve regeneration, increases the abundance of mRNAs for myelin proteins and promotes muscle reinnervation. After the sciatic nerve had been crushed the number of regenerating axons in the distal stump was markedly and highly significantly increased by glycosaminoglycan treatment throughout the experimental period. The increased number of axons was correlated with increased axon and fibre (axon + myelin) diameter. The abundance of mRNAs for P_o protein and myelin basic protein of regenerating nerves was also affected by treatment with glycosaminoglycans. The increase in mRNA was also observed in the contralateral unlesioned nerve. Such a phenomenon did not occur in saline-treated rats. Glycosaminoglycan treatment markedly increased the number of muscle fibres reinnervated and accelerated the restoration of muscle twitch tension elicited by nerve stimulation. The effect was particularly evident during the early stages (16 and 21 days after nerve crush) of muscle reinnervation.     

Bone morphogenetic proteins: background and implications for oral reconstruction

Abstract For over 30 years now, research has been carried out to isolate and purify bone morphogenettc protein (BMP), a substance which has been shown to induce heterotopic bone formation in various animal species. Recent advances in the fields of developmental biology, molecular biology, genetics and wound healing, have shown that the BMPs are not only responsible for postfetal bone induction (including normal bone remodeling, healing and repair), but are also critical during embryogenesis, not only in regards to the skeletal system, but quite possibly in the morphogenesis and pattern formation of other tissues and organs as well, Therefore. BMPs have the potential as a therapeutic utility in orthopedic and dento-alveolar reconstruction.     

Laser Doppler flowmetry of blood perfusion in mucoperiosteal flaps covering membranes in bone augmentation and implant procedures. A pilot study in dogs.

In guided tissue regeneration (GTR) procedures, flap recession or sloughing may occur as an unwanted sequel to the placement of a membrane. This study was designed to assess the applicability of laser Doppler flowmetry (LDF) in the evaluation of blood perfusion in the mucoperiosteal flap covering the membrane. Five Labrador dogs were initially used inthe study, but one animal was later excluded due to post‐operative problems. Maxillary premolar teeth were extracted and full thickness mucoperiosteal flaps were raised. Following removal of the buccal bone plate, 4 titanium implants were placed on each side. An experimental biodegradable polylactic‐acid membrane was placed over the fixtures on one side to allow for GTR. The mucoperiosteal flap was repositioned and secured with sutures. The contralateral side served as control with no membrane. Blood perfusion was measured in the flaps before surgery, immediately after suturing and at 24, 48 and 72 h postoperatively. A laser Doppler flowmeter was used to assess the blood perfusion. In 3 animals the membrane was exposed within 2 weeks post‐operatively, and in these 3 animals the LDF values were lower on the membrane side than on the control side. The mean LDF value was lower on the membrane side for each of the 4 periods studied. The tindings suggest that LDF can be a valuable method to study blood perfusion of oral mucosal flaps and that there may be a relationship between a reduced relative LDF value and subsequent exposure of the membrane to the oral environment.     

Strategy and timing of peripheral nerve surgery

The authors review the latest theories of peripheral nerve regeneration and repair. They present their research on nerve regeneration including the alterations in the mother cell body, and in the distal part of the axon, and the time required to reach the best production of amino acids for cytoskeleton reconstruction. Other research of particular interest which is presented regards the chemotactic arrangement of motor and sensory axons inside a vein. This research has shown that the axons are able to find their way to the appropriate (sensory or motor) distal endoneural tubes.Adoption phenomena are also presented.The discussion of surgery includes the type (suture, glueing, grafts, tubulization) and the time of surgical repair. Timing and repair strategies are related to the site of the lesion (which can require that a greater or smaller amount of cytoskeleton be reconstructed), the type of the injury, the state of surrounding tissues, the age of the patients, injuries to muscles, tendons, bones, vessels and skin. A scheme of strategy is proposed.     

异体硬脊膜桥接周围神经缺损的实验研究

探讨异体硬脊膜修复周围神经缺损的可行性。方法：采用狗的异体硬脊膜桥接缺损２ｃｍ的狗腓总神经，对照组仅切取２ｃｍ神经而不作处理。在术后不同时间段作大体观察、神经电生理检测、光镜利电镜检查。结果：再生神经纤维在管腔内呈纵行整齐排列Ｔ偕窬宋峤岣弧＝崧郏菏5验结果证实异体硬脊膜能成功地引导周围神经再生。     

预变神经段修复神经缺损的实验研究

目的探讨不同预变时间组移植神经对神经再生的影响。方法以ＳＤ大鼠的不同预变时间组的尺神经作为移植神经，修复其正中神经的缺损。实验侧按移植神经预变时间的不同分为０、１、２、３、４、８周共６组，每组６只ＳＤ大鼠。移植后１２周，检测实验侧趾屈肌群的张力、最大收缩力、再生神经的形态及神经轴突的截面积。结果用预变１周的尺神经修复正中神经后，其趾屈肌群的张力及最大收缩力的恢复率达到正常对照组的８１．１％及８５．９％。显微镜下观察，预变１周组和其它各时间组相比，其再生的神经轴突最多，发育最成熟。结论用预变１周的神经段修复神经缺损，其神经再生能力最佳