Motor reflex responses elicited by cutaneous stimulation in the regenerating nerve of man: Axon reflex or ephaptic response?

In 57 of 60 nerves (29 median and 31 ulnar) sutured at the wrist, forearm and arm, we recorded motor responses in thenar or hypothenar muscles by electrical stimulation of the corresponding fingers. Recordings were made at different times during the process of regeneration, ranging from 3 months up to 11 years. The responses showed a constant shape and latency to every stimulation (simple or repetitive). The latency was shorter the more distal the level of injury and the greater the elapsed time from the reinnervation. The point of "reflexion" of the responses is at or very near the line of nerve suture. The electrophysiological behavior of the responses fits well with either the criterion of axon reflex or ephaptic response. We discuss both possibilities and conclude that it is not possible, with the electrophysiological technique that we used, to distinguish between an axon reflex and an ephaptic response.     

Connective tissue repair in circumferential periodontal defects in dogs following use of a biodegradable membrane

A biodegradable polylactic acid membrane was evaluated for its ability to enhance periodontal regeneration. In 8 Labrador dogs, circumferential defects were created around the maxillary 1st premolars. The defects were combination "1-wall vertical and horizontal". A membrane was adjusted to cover the defect on one side of the jaw, while the contralateral tooth served as control without membrane. After 3 months, healing was evaluated histologically. The results demonstrated that the amount of connective tissue repair with newly formed cementum approximated 50% of the defect height for both test and control groups. Thus, no advantage to the use of membrane was found, which is contradictory to the findings of our previous dog study using the same biodegradable membrane. The possible reasons for this difference in results are discussed relative to suggested mechanisms for membrane effects in periodontal regeneration.     

脑弥漫性轴索损伤32例影像学诊断分析

目的　通过对脑弥漫性轴索损伤 (DAI)临床、CT及MRI的影像学表现的分析 ,以期提高对DAI的诊断水平。方法　分析有完整临床资料 ,同时进行过CT和MRI检查 ,特别是CT检查相对阴性的 32例DAI患者的影像学诊断结果。结果　 32例DAI患者CT检查相对阴性 ,MRI检查发现在胼胝体、基底节、脑干及灰白质交界处多发小的异常信号灶。结论　临床拟诊DAI的患者在CT检查相对阴性时可进行MRI检查 ,其MRI影像学表现有助于DAI的诊断     

牛坐骨神经中神经再生抑制物的分离与鉴定

目的 在周围神经内寻找与中枢神经内轴突生长抑制因子有相同生物学活性的神经再生抑制物。方法 取新生小牛坐骨神经提取液经ＳｅｐｈａｃｒｙｌＳ－１００凝胶柱层析,得洗脱峰,再将各峰成分用不同分子的滤管超滤分别得到６组不同Ｍｒ的粗提液,将各组分加入到体外培养的ＰＣ１２细胞中观察细胞生长情况,并检测细胞活性。细胞活力检测指标是ＭＴＴ法细胞活性检测和细胞总蛋白含量测定。结果 有抑制活性的物质主要集中在Ｍｒ〈１     

A morphological,biochemical, and radioautographic study in rats

Splenectomy has long been an establishmd surgical procedure in various conditions, including trauma. Because total splenectomy has often been correlated with sepsis, every surgeon tries to preserve as much of the injured spleen as possible. Contradictory reports have been published as to whether regeneration of the remaining splenic tissue is possible. In the present study, 28 Sprague-Dawley rats ( 100 g) were divided into four groups. They underwent two-thirds partial splenectomy; the remaining splenic tissue was examined after 1 day, 1 week, 1 month and 3 months postoperatively. The following parameters were determined: weight, length, and protein and deoxyribonucleic acid (DNA) content of the remaining spleen. The incorporation of ³H-thymidine into the remaining spleen tissue was also measured. Histology and radioautography were studied in parallel. Results were compared with control animals that were operated upon but with no partial splenectomy. One day, 1 week, and 1 month following partial splenectomy, a slight increase in weight, length, protein, and DNA content as well as incorporation of the radioisotope into cellular DNA was found. By 3 months after the operation, there was no difference in the above parameters between the experimental animals and controls.Radioautographs indicated that most of the cells containing the isotope were situated in the perinodular areas in the red pulp, accompanied by an increased number of inflammatory cells. We found this cell proliferation mainly along the cut surface of the spleen. The slight increase that was found in all the parameters examined up to 1 month after partial splenectomy is an inflammatory response and not regeneration of the spleen.     

引导组织再生术屏障膜放置时间的研究

在 ３０ 只成年兔的下颌两切牙唇侧牙槽骨制备 １０ｍ ｍ ×５ｍ ｍ 的开窗骨缺损,其表面覆盖 Ｇｏｒｅ Ｔｅｘ 膜。该膜分别于术后 １、２、３、５ 周取出,以不放膜组为空白对照。所有动物５ 周处死,标本作组织学分析。结果表明,２ 周取膜组较空白对照组有更多的新骨形成,而 ３ 周或 ５ 周取膜组织的再生量无进一步增加。提示在引导兔开窗骨缺损的牙周再生中,屏障膜放置所需要的最适宜时间是 ２ 周。     

Neuron-specific enolase as an effective immunohistochemical marker for injured axons after fatal brain injury

Recently, it has been reported that a diagnosis of diffuse axonal injury in cases with a short survival period can be made with the use of immunolabelling for β-amyloid precursor protein (APP). We examined whether immunostaining for neuron-specific enolase (NSE) can also be a useful marker for the detection of axonal injury in its early stages. Sections of the corpus callosum from 19 cases of head injury and from 9 cases of no head injury were immunostained for NSE and stained by the standard Holmes’ silver method. For comparison, serial sections from several cases were immunostained for APP. Immunostaining for NSE as well as for APP, labelled injured axons in head injury cases with as early as 1.5 h survival where Holmes’ staining failed to detect any changes of axons. Since NSE and APP labelled only injured axons but not normal axons, the results were readily interpretable. These findings indicate that NSE should be an effective marker for the detection of axonal injury in its early stages. Received: 7 December 1998 / Received in revised form: 11 March 1999     

Changes in liver regenerative factors in a case of living-related liver transplantation

Liver regeneration in a patient with fulminant hepatic failure (FHF) who underwent living-related partial liver transplantation (LRLT) was investigated regarding hepatic growth factors. The patient was a 16-yr-old Japanese male who developed severe subacute FHF. LRLT was performed using an extended left lobe of the ABO matched patient's mother. In the recipient, the pre-transplant levels of both plasma hepatocyte growth factor (HGF) and transforming growth factor (TGF)-beta were extremely high and rapidly decreased following the liver replacement. The liver volume evaluated using a CAT scan increased 195% after 2 wk in graft liver and 110% after 2 wk in the hepatectomized donor. The explanted liver (FHF liver), the liver from donor (normal liver), and the graft liver [the 3rd post-transplant day (POD 3)] were all investigated immunohistochemically. FHF liver: No liver regeneration was observed [proliferative cell nuclear antigen (PCNA) labeling index (L.I.): 0%]. In the liver, both HGF in the hepatocytes and c-met on the membrane of the hepatocytes were positive. TGF-beta was positive in the hepatocytes and no apoptosis was detected by the TUNEL method. Donor liver (POD 0): Few PCNA stained hepatocytes were detected. No HGF was detected but c-met was clearly detected on the cell membrane of the hepatocytes. Neither TGF-beta nor apoptosis was detected. Graft liver (POD 3): The PCNA L.I. was conspicuous at 40%. HGF was positive in non-parenchymal cells and c-met was positive in the cytoplasm of the hepatocytes. TGF-beta was negative while apoptosis was positive in the zone 3 hepatocytes. In conclusion, these findings suggested that the liver of the patient with FHF did not respond to liver regenerative stimulus, in part, through involvement of inhibitor TGF-beta. On POD 3, the transplanted graft was in a vigorous regenerative status in comparison to that in the hepatectomized donor. The HGF/c-met system is thought to be involved in the mechanism of regeneration. Intrahepatic apoptosis was detected in the graft on the 3rd post-transplant day probably due to transient ischemia in the liver, which was not related to the Fas/Fas-ligand system.     

Regeneration of neuronal nitric oxide synthase (nNOS)-containing nerve fibers in rat corpus cavernosum

Aim: To investigate the effect of cavernous nerve injury on the nNOS-containing nerve fibers in rat corpus cavernosum.Methods: Thirty-three male SD rats were randomized into 3 groups: 5 rats underwent pelvic exploration without tran-section of cavernous nerve as the sham-operated controls, the unilateral injury group (14 rats) had the cavernous nerve cuton one side, and the bilateral injury group (14 rats) had the nerves cut on both sides. Corpora cavernosa were harvestedat the 3rd week and 6th month after surgery, nNOS-positive nerve fibers were examined with strepavidin peroxidase im-munohistochemistry techniques (SP method). Results: After bilateral ablation, the nNOS-positive nerve fibers weresignificantly decreased at both the 3rd week ( 17 ± 4) and the 6th month (16 ± 4). For the unilateral injury group, thenNOS-positive nerve fibers were similarly decreased on the side of the neurotomy at the 3rd week (18 ± 6), but by the 6thmonth, the number increased significantly (61±9) and approximated th