视神经半损伤后复合神经营养因子辅助再生的动态PVEP研究

目的：探讨视神经（optic nerve,ON）损伤后的自然修复再生和用脑源性神经营养因子（BDNF）及睫状神经营养因子（CNTF）互补辅助再生的图形翻转视觉诱发电位（PVEP）变化特征，寻找ON有效再生的新途径。方法：将40只猫作为实验对象，术前随机平均分4组：正常对照组，球后ON半径切断组（ON1／2I）、ON半径切断并定时向玻璃体内玻璃体内注射BDNF和CNTF复合因子辅助再生组（ON1／2I＋BF）。经眶外侧入路行手术开眶，在球后5mm处测量ON直径数值，并用宝石卡尺刀行ON半径切断术。ON1／2I＋BF组在术后即日注射BDNF和CNTF复合液（10ng），并在以后注射等量BDNF和CNTF复合液，2次／w。在ON损伤后1个月、4个月和8个月，3次行PVEP动态检测，结果：在ON1／2损伤后1个月时，与N组相比，ON1／2损伤各组PVEP的N1－P1振幅显著降低和P1潜时延迟；ON1／2IT ON1／2I＋PS组与ON1／2I＋BF组比较，也出现了PVEP的N1－P1振幅降低和P1潜时的延迟。在ON1／2损伤后第4个月时，ON1／2I组和ON1／2I＋PS与N组比较，其PVEP的P1潜时显著延迟（P＜0．001，P＜0．001）和N1－P1幅度显著降低（P＜0．001，P＜0．001）。而ON1／2I＋BF组与N组比较，两者PVEP的P1潜时和N1－P1幅度差异虽然具有显著性（P＜0．05），但与ON损伤后1个月时同组动物的PVPEP测试结果比较，已开始出现恢复型曲线图谱，两者的差异亦有显著性（P＜0．05，P＜0．01）。在ON1／2损伤后8个月后，ON1／2I组和ON1／2I＋PS组的PVEP的P1潜时仍然显著延迟，N1－P1幅度仍然显著降低，未见明显的恢复型曲线图出现。而ON1／2I＋BF组PVEP的P1潜时和N1－P1幅度与ON损伤后4个月时的PVEP测试结果比较，差异却具有显著性（P＜0．01）；与ON1／2切断组和ON1／2I＋PS组比较，差异也具有显著性（P＜0．01），与N组比较，其PVEP的P1潜时未见延迟（P＞0．05），但N1－P1幅度仍低于正常对照组（P＜0．05）。结论：（1）视神经1／2损伤后可以添加条件因素辅助其再生，BDNF和CNTF对促进视神经损伤后的再生有调节局部微环境和互补促生长作用。（2）视神经1／2损伤前后，其有视觉电生理学的动态变化特征，主要表现为：在ON损伤后，PVEP的P1潜时重度延迟和N1－P1波幅值大幅度衰减，而当应用神经营养因子拮抗视神经损伤效应后的1个月、4个月和8个月时，则逐渐出现PVEP的P1潜时恢复和N1－P1波幅值的提高。这说明1／2损伤的ON在BDNF和CNTF的互补作用下，可以修复再生和恢复其视觉信息的传导功能。BDNF和CNTF对促进视神经损伤后的轴突再生有互补促生长作用。     

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.     

Axonal regeneration in dorsal spinal roots is accelerated by peripheral axonal transection

Regeneration of crushed axons in rat dorsal spinal roots was measured to investigate the transganglionic influence of an additional peripheral axonal injury. The right sciatic nerve was cut at the hip and the left sciatic nerve was left intact. One week later, both fifth lumbar dorsal roots were crushed and subsequently, regeneration in the two roots was assessed with one of two anatomical techniques. By anterograde tracing with horseradish peroxidase, the maximal rate of axonal regrowth towards the spinal cord was estimated to be 1.0 mm/day on the left and 3.1 mm/day on the right. Eighteen days after crush injury, new, thinly myelinated fibers in the root between crush site and spinal cord were 5-10 times more abundant ipsilateral to the sciatic nerve transection. The central axons of primary sensory neurons regenerate more quickly if the corresponding peripheral axons are also injured.     

湿性烧伤治疗技术在深度烧伤的临床应用体会

目的：总结和简述烧伤湿性医疗技术在治疗深度烧伤的临床应用经验。方法：对我院近年来150例深度烧伤病人全程股规范应用湿性医疗技术治疗的创面，深度创面采用耕耘疗法。结果：150例病人创面全部愈合，创面愈合时间最短10天，最长56天。没有一例植皮，创面均达到生理性愈合，无畸形，无功能障碍。结论：湿性疗法对深度烧伤疗效显著，深度烧伤创面能实现生理性愈合，达到烧伤皮肤原位再生之目的。     

Principles for reconstruction of traumatic ear defects

Summary Traumatic defects of the auricle are quite common. The eventual success of the repair is considerably influenced by the initial treatment. The different parts of the auricle require different approaches. This paper presents our methods for repairing damage to the cartilaginous frame using autologous ear cartilage grafts, and local flaps from the mastoid region to cover soft tissue defects.     

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。