周围神经选择性再生的机制

<正>周围神经损伤是临床上的常见损伤,其再生的效果取决于两个重要的方面:一方面是再生神经的"数量";另一方面是再生神经的"质量"或者效率。周围神经系统损伤后再生神经纤维是否能够对恰当的靶器官形成有效的再支配,即神经靶向投射的准确率是功能恢复的关键之一。然而,临床上再生的神经元轴突经常发生错配。这种不准确的再生,即使     

神经支配对兔后肢缺血诱导侧支血管生长过程中巨噬细胞标记物、细胞间黏附分子和血管细胞黏附分子表达的影响

目的:通过比较去除支配血管壁的神经,观察神经支配对侧支血管巨噬细胞标记物(RAM11)、细胞间黏附分子(ICAM)和血管细胞黏附分子(VCAM)表达的影响.方法:20只新西兰大白兔,左侧行股动脉结扎,右侧行股动脉结扎加坐骨神经和股神经切除,7 d后将动物处死,应用免疫荧光组织化学技术,观察单纯结扎和结扎加去神经侧RAM11、 ICAM和VCAM在侧支血管的表达变化,兔前肢大小相似的正常血管用作正常对照.结果:正常血管ICAM和VCAM的表达非常低,外膜中可见数目很少的RAM11阳性细胞;股动脉结扎侧,侧支血管ICAM、VCAM和RAM11的表达均明显上调,RAM11阳性细胞主要在外膜聚集,在中膜也可见,ICAM表达主要在血管内皮细胞,而VCAM除了在血管内皮细胞有表达外,在外膜也有表达;股动脉结扎加去神经侧,ICAM、 VCAM和RAM11的表达比股动脉结扎侧有所下调,其荧光强度的比较有统计学意义.结论:在缺血诱导的兔后肢侧支血管生长模型中,去除血管壁的神经导致了炎症分子ICAM、 VCAM和RAM11的阳性细胞减少,表明血管壁神经对RAM11、 ICAM和VCAM的表达调节有重要影响.     

一例GJB1基因新变异导致的X连锁腓骨肌萎缩症

患者28岁,男性,因进行性四肢无力、肌肉萎缩10年入院。10年前无明显诱因缓慢出现右上肢无力伴肌肉萎缩,表现为右手指抓东西、拿东西无力、困难,遇冷水时手指呈屈曲状难以伸展,伴手部、前臂肌肉萎缩,症状从远端起病向近端发展,症状逐渐加重,后又出现左上肢及双下肢无力、肌萎缩(远端为主)。病程中无感觉异常、感觉减退及肌肉跳动等不适。家族史无特殊,父母无相关表型。查体:神清语利,高级神经功能活动正常,颅神经未见异常。     

硫酸软骨素蛋白聚糖与脊髓损伤轴突再生

脊髓损伤后传导束的纤维不能有效再生是脊髓损伤后修复与功能重建的难点之一,其中屏障之一是神经胶质瘢痕,主要由星形胶质细胞和硫酸软骨素蛋白聚糖（chondroitin sulfate proteoglycans,CSPGs）组成,轴突不能穿过神经胶质而再生,屏障导致营养不良,再生受阻。目前有关胶质瘢痕的形成过程与调控、CSPGs参与胶质瘢痕形成的机制、以及如何有效地控制瘢痕的形成从而促进轴突再生,仍存在许多未知领域。     

失重飞行对骨骼肌结构和功能的影响

空间飞行可导致骨骼肌出现废用性变化.本文综述了对失重/ 模拟失重条件下肌肉形态结构、代谢、功能研究的新进展.     

全身振动训练对前交叉韧带重建后影响的Meta分析

目的：全身振动训练近年来被广泛运用于前交叉韧带重建后康复当中,然而其疗效仍存在争议。文章采用Meta分析方法,系统评价全身振动训练对前交叉韧带重建后的影响,以期为全身振动训练的临床应用提供循证医学证据。方法：计算机检索PubM ed、Embase、The Cochrane Library、Web of Science、EBSCO、中国知网、万方和维普数据库的相关文献,收集全身振动训练对前交叉韧带重建后患者影响的随机对照试验,检索时限均为各数据库建库至2022-07-16。结局指标包括股四头肌峰值力矩、腘绳肌峰值力矩、膝关节角度重现误差、Biodex偏移指数及Lysholm膝关节功能评分共5个连续性变量,采用Cochrane风险偏倚评估工具和Jadad量表对纳入的文献进行质量评价,应用RevMan 5.3软件对结局指标进行Meta分析。结果：(1)共纳入10项随机对照试验,包括372例前交叉韧带重建后患者,纳入文献整体质量较高。(2)Meta分析结果显示：与对照组相比,全身振动训练可以显著提升股四头肌峰值力矩(SMD=0.75,95%CI:0.20-1.30,P=0.008)和腘绳肌峰值...     

神经元性组织工程化周围神经的在体研究

周围神经缺损后的修复与功能重建是世界性的难题.自体神经移植会造成取材部位的功能缺失和长度大小、口径等难以匹配等问题.目前多以雪旺细胞或干/祖细胞为种子细胞,体外或在体诱导分化为雪旺细胞构建组织工程化神经,但存在新生轴突需跨越两个吻合口、增加了神经再生的难度,神经-效应器失配及效用器废用性萎缩等问题.     

bFGF对同种异体神经移植后周围神经再生的影响

目的 :探讨bFGF对同种异体神经移植后周围神经再生的影响。方法 :将反复冻融的大鼠神经移植于另一大鼠的坐骨神经 ,实验组注射bFGF 1 0 0u/d共 1 0d ,对照组注射生理盐水 1 0d。术后大鼠存活 1 2周 ,光镜下用体视学方法测试再生神经纤维的面数密度 (NA)、面积密度 (AA)、横切面面积 (AE)、脊髓前角运动细胞和脊神经节细胞的体密度 (VV)、数密度 (NV)。结果 :两组均可见再生神经纤维长入异体移植神经并向远段延伸。实验组再生神经纤维的NA、AA、脊髓前角运动细胞和脊神经节细胞的VV、NV 与对照组的比较 ,有显著性差异。结论 :bFGF能促进周围神经再生 ,对脊髓前角运动细胞和脊神经节细胞的存活有保护作用。     

热射病猪血管内皮细胞损伤的病理变化及相关黏附分子表达北大核心

背景:热射病是一种死亡率极高的疾病,是由高温引起的广泛内皮细胞损伤及多脏器功能衰竭的临床综合征,常见的并发症是凝血功能异常,而血管内皮病变在重度中暑引发的凝血功能紊乱中发挥关键作用。目的:观察热射病猪血管内皮细胞损伤的病理变化特点及相关黏附分子细胞间黏附分子1的表达。方法:选取12只普通级健康雄性巴马小型猪,体质量15-20 kg,采用随机数字表法分为常温对照组及热射病组,每组6只。热射病组建立高温高湿环境下重度中暑猪模型,而常温对照组小猪置于恒温恒湿气候舱中。采集两组实验前、后静脉血,检测血常规、凝血功能指标;取相同部位的腹主动脉、冠状动脉、肺组织标本,苏木精-伊红染色观察两组标本病理损伤变化;采用免疫组织化学染色对比两组细胞间黏附分子1的表达水平;高倍透射电子显微镜观察冠状动脉及肺组织超微结构变化。结果与结论:①常温对照组实验前、后活化部分凝血活酶时间、凝血酶原时间、血浆D-二聚体、纤维蛋白原降解产物水平及红细胞、血小板计数比较,差异无显著性意义(P>0.05);②热射病组实验后红细胞计数、活化部分凝血活酶时间、凝血酶原时间、血浆D-二聚体、纤维蛋白原降解产物水平高于实验前,且高于常温对照组;血小板计数低于实验前,且低于常温对照组,差异有显著性意义(P<0.05);③苏木精-伊红染色:常温对照组腹主动脉、冠状动脉、肺微血管组织病理结构正常;热射病组腹主动脉内皮细胞轻度水肿,未见明显异常;冠状动脉可见血栓形成、内皮细胞脱落、坏死,数量减少;肺微血管弥漫性出血、内皮细胞数量明显减少;④免疫组织化学染色结果显示:常温对照组腹主动脉、冠状动脉、肺组织观察到内皮细胞浆膜上有数量较多、呈棕黄色线状的细胞间黏附分子1阳性表达;热射病组内皮细胞浆膜上染色数量明显减少,或表达缺如,呈浅黄色的细胞间黏附分子1弱阳性表达;热射病组血管组织中细胞间黏附分子1平均吸光度值低于常温对照组(P<0.05);⑤电镜观察超微结构:热射病组冠状动脉组织可见细胞核形状不规则,线粒体肿胀;热射病组肺组织可见少量细胞核及线粒体肿胀;⑥提示热射病可导致小型猪血管内皮细胞损伤,且以微小血管损伤表现显著。     

前交叉韧带重建后肌肉等长发力率及与功能表现的关系

背景：前交叉韧带重建后肌肉功能的恢复通常评估肌肉的最大力量,最近的研究认为还应考虑神经肌肉功能,比如肌肉等长发力率,即在肌肉等长收缩条件下测量不同时间间隔的力-时间曲线斜率。目的：阐述前交叉韧带重建后患者肌肉等长发力率的研究现状与不足,分析术后不同时间内股四头肌和腘绳肌等长发力率的缺陷程度;等长发力率对术后患者功能表现的影响,为优化前交叉韧带重建后康复、减少患者二次损伤以及降低膝骨关节炎发生率提供重要信息。方法：检索中国知网、维普、万方和PubMed数据库,以“前交叉韧带,发力率”为中文检索词,以“anterior cruciate ligament,rate of force development,rate of torque development”为英文检索词,按照纳入和排除标准最终纳入69篇文献。结果与结论：(1)大多数研究发现前交叉韧带重建后半年内患者双侧肌肉等长发力率存在缺陷,双侧腘绳肌早期等长发力率(即肌肉收缩100 ms时间段内任意时间间隔的力-时间曲线斜率)在半年后有显著改善,但双侧股四头肌早期等长发力率长期缺陷,表明术后股四头肌神经肌肉功能长期受损。(2)有关晚期...     

The response of regenerating peripheral neuntes to a grafted optic nerve

Summary Optic nerves, both viable (fresh or pre-degenerate) or non-viable (frozen-thawed) were grafted between the proximal and distal stumps of freshly transected sciatic nerves, using either 10/0 sutures or strips of nitrocellulose paper. The majority of regenerating peripheral neuntes, always in association with Schwann cells, avoided the viable optic nerve grafts, growing along the outside of the grafts in well vascularized minifascicles until they gained the distal stumps. A very small number of axons entered the grafts and grew, for distances typically less than 2mm, between layers of astrocyte processes. The number of axons entering was not increased by using predegenerate grafts or by blocking Schwann cell proliferation in the proximal stumps by pre-treating the latter with mitomycin C. There was no evidence of a continuous cellular-acellular partition between graft and host during the outgrowth phase of the neurites: it was concluded that axons failed to enter the grafts as a result of inhibitory interactions between Schwann cells and astrocytes. When grafts were rendered acellular, all structured debris, including recognizable components of the extracellular matrix, was rapidly removed and the space thus vacated was invaded by minifascicles of Schwann cells and regenerating neurites. Glial fibrillary acidic protein-positive astrocytes and carbonic anhydrase II-positive oligodendrocytes persisted within viable grafts for 17 months; they did not migrate into the surrounding nerve.     

Factors contributing to thixotropy of inspiratory muscles

Thixotropy is a passive property of the skeletal muscle dependent on the muscle's immediate history of contraction and length change. Thixotropic properties of inspiratory muscles, introduced by forceful muscle contraction at an inflated lung volume, cause an increased end-expiratory position (EEP) of the rib cage. We searched for factors contributing to the development of inspiratory muscle thixotropy in nine healthy subjects. Using induction plethysmography, we examined aftereffects on EEP of the duration of inspiratory muscle contraction and subsequent muscle relaxation. We also studied effects of inspiratory effort intensity measured by mouth pressure at different lung volumes. EEP elevation was noted subsequent to 5-s contraction followed by 2-s relaxation and was enhanced when conditioned at higher lung volumes with a strong inspiratory effort. Our results suggest four factors that influence inspiratory muscle thixotropy: (1) intensity of muscle contraction, (2) lung volume when contraction occurs, (3) duration of contraction, and (4) muscle relaxation.     

Ganglioside 9-O-acetyl GD3 expression is upregulated in the regenerating peripheral nerve

Evidence accumulates suggesting that 9-O-acetylated gangliosides, recognized by a specific monoclonal antibody (Jones monoclonal antibody), are involved in neuronal migration and axonal growth. These molecules are expressed in rodent embryos during the period of axon extension of peripheral nerves and are absent in adulthood. We therefore aimed at verifying if these molecules are re-expressed in adult rats during peripheral nerve regeneration. In this work we studied the time course of ganglioside 9-O-acetyl GD3 expression during regeneration of the crushed sciatic nerve and correlated this expression with the time course of axonal regeneration as visualized by immunohistochemistry for neurofilament 200 in the nerve. We have found that the ganglioside 9-O-acetyl GD3 is re-expressed during the period of regeneration and this expression correlates spatio-temporally with the arrival of axons to the lesion site. Confocal analysis of double and triple labeling experiments allowed the localization of this ganglioside to Schwann cells encircling growing axons in the sciatic nerve. Explant cultures of peripheral nerves also revealed ganglioside expressing reactive Schwann cells migrating from the normal and previously crushed nerve. Ganglioside 9-O-acetyl GD3 is also upregulated in DRG neurons and motoneurons of the ventral horn of spinal cord showing that the reexpression of this molecule is not restricted to Schwann cells. These results suggest that ganglioside 9-O-acetyl GD3 may be involved in the regrowth of sciatic nerve axons after crush being upregulated in both neurons and glia.     

GAP-43 in the axons of mammalian CNS neurons regenerating into peripheral nerve grafts

Summary Although mature mammalian CNS neurons do not normally regenerate axons after injury, it is well established that they will regrow axons over long distances into peripheral nerve implants. We have autografted segments of sciatic nerve into the brains of adult albino rats and have used light and electron microscopic immunocytochemistry to examine the distribution of the growth associated protein GAP-43 in and around the graft in the first two weeks following implantation. GAP-43 was present, 3–14 days after grafting, in small non-myelinated axonal sprouts in the brain parenchyma around the proximal tip of the graft. At 11–14 days after implantation similar sprouts within the graft itself were GAP-43 immunoreactive. The sprouts were either naked or associated with other cell processes (chiefly of Schwann cells; to a lesser extent of astrocytes). We also show that small numbers of neuronal perikarya around the tip of the graft become GAP-43 immunoreactive 11–14 days after implantation. Thus mature mammalian CNS neurons regenerating axons into a PNS graft display a marked increase in their content of GAP-43. In addition, we report that small plaques of GAP-43 reaction product are sometimes present on the plasma membranes of Schwann cells or astrocytes adjacent to immunoreactive axons, and that narrow sheet-like or filopodial processes of astrocytes, Schwann cells and possibly other non-neuronal cell types, may contain small amounts of GAP-43.     

Factors contributing to the variability in muscle ageing

Ageing is accompanied with a progressive loss of muscle mass and force generating capacity. Ultimately, the muscle wasting and weakness may dramatically impact on mobility and the quality of life, where the elderly has increasing problems with performing activities of daily life, such as rising from a chair or climbing stairs. The rate of structural and functional deterioration of muscle appears to vary considerably between people. Part of the variation in the ‘rate of muscle ageing’ is attributable to genetic factors, the timing of changes in circulating hormones and the presence or absence of chronic low-grade systemic inflammation. Where an individual cannot change much in his or her genetic constitution, circulating hormones and systemic inflammation, (s)he can still significantly slow the rate of muscle ageing by an adequate dietary intake and regular physical activity. Finally, it is suggested that age-related alterations in the capillary bed may negatively affect muscle mass.     

周围神经端侧吻合再生纤维来源的实验研究

目的：探讨周围神经端－侧吻合后再生纤维（侧芽）的来源。方法：将Wistar大鼠左侧腓总神经切断后端一侧吻事到外膜开窗的胫神经干 ,术后15周对胫神经和腓总神经分别用快兰和核黄作神经干注射标注,取背根神经节（DRC）荧光显微镜下观察被标记细胞,取吻合口附近的胫,腓神经段经饿酸染色后在光镜下观察腓总神经内轴突与胫神经轴突的关系。结果：实验组带根节内未发现双标细胞,光镜下,可清晰地见到左侧腓总神经内的再生纤维从胫神经近侧端下行而至。结论：周围神经端一侧吻合腓总神经内的再生纤维来自于胫神经的侧芽缺乏依据。因无法排除来自腓总神经近端生长锥和受损胫神经纤维生长锥的可能。     

Factors contributing to the length of general practice consultations

Ten general practitioners in a study of general practice consultations were shown to differ significantly in the time they spent in their consultations. Patient demographic characteristics contributed little to differences in consultation time. Consultations in which (a) there was a diagnosis of psychological disorder, (b) the practitioner and the patients focused attention on psychosocial matters, and (c) psychotropic drugs were prescribed, were found to be associated with increased length of consultation time.     

霍乱毒素及联合外周神经对视神经损伤后视网膜节细胞再生的影响

目的探讨霍乱毒素(CTx)及其联合外周神经对成年金黄地鼠视神经损伤后再生视网膜节细胞胞体及轴突的影响。方法扎断(MC)成年金黄地鼠视神经(ON)近端,玻璃体内注射CTx,或联合插入小段坐骨神经分支(SN),或切断视神经近端(ONT)并缝接一段自体坐骨神经,并在玻璃体内注射CTx。动物随机分为MC+CTx组、MC+CTx+SN组、ONT+SN+CTx组。各组动物均存活4周。用荧光金逆行标记再生的轴突,在荧光镜下观察视网膜平铺片中再生的视网膜节细胞大小及视神经切片内再生的轴突。结果MC+CTx组、MC+CTx+SN组、ONT+SN+CTx组再生RGCs周长依次为(56.84±18.08)μm、(83.20±28.28)μm、(94.01±32.44)μm,各组间差异有显著性。再生的RGCs有1-2个轴突,在视神经内多呈波浪状,且多走行在视神经边缘。结论各实验组促进再生的视网膜节细胞大小不同,提示霍乱毒素及其联合外周神经可能促进视网膜不同亚型节细胞再生。