Prevention of spinal cord injury: an elementary education approach.

Spinal cord injury (SCI) results in permanent paralysis and most often happens to teenagers and young adults. High risk behaviors are most often the cause; therefore these injuries are often preventable. In response to a gap in existing prevention programs, an elementary age SCI prevention program was developed, designed for implementation by teachers. Evaluation was carried out via a quasi-experimental pre-post comparison group design. Experimental students demonstrated significantly improved knowledge of SCI and its prevention. Similar changes in self-reported safety belt use were not noted. Development of the curriculum, related grant activities, and plans for national dissemination are described.     

Presymptomatic diagnosis of SMA III by genotype analysis

Linkage analysis and prenatal prediction in families segregating autosomal recessive spinal muscular atrophy (SMA) has become feasible since the assignment of the locus responsible for type I-III SMA to region 5q12-q13.3. We have performed a segregation study of SMA in Italian families using molecular probes and highly informative PCR-based polymorphic markers. In one family, a 7-year-old boy affected with type III SMA and an 8-year-old apparently healthy brother had identical haplotypes. These findings prompted us to reexamine the apparently unaffected child. His neurological exam was normal. However, the electromyography (EMG) showed a pattern consistent with chronic SMA. To our knowledge this is the first example of presymptomatic diagnosis of SMA based on genotype analysis. © 1993 Wiley-Liss, Inc.     

Non-muscarinic effects of atropine on calcium conductances in cultured mouse spinal cord neurons

Cultured neurons derived from mouse spinal cord were studied using intracellular recording techniques. Effects of muscarinic cholinergic antagonists (atropine) on voltage-dependent membrane events, which could not be related to muscarinic receptors are described. Atropine (in nanomolar to micromolar concentrations) blocks calcium conductances in a manner which is not blocked by carbachol (100 microM). A direct effect of atropine on membrane Ca2+ conductances is suggested.     

Partial trisomy 6p and partial monosomy 9p from a de novo translocation 46, XY, -9, + DER(9)T(6:9)(p211:p24)

This report describes an adult male with a partial trisomy 6p(p211-pter) and a partial monosomy 9p(9p24-pter) resulting from a de novo unbalanced translocation. This patient does not show the classical featured of the 9p partial monosomy syndrome, thus disputing the claim of Hoo et al. (1982) that 9p24 is the critical segment for the monosomy syndrome. Partial trisomy for 6p has only been previously reported in children. In addition to the chromosomal anomalies, the patient has autosomal recessive spinal muscular atrophy with a different age of onset than two affected sibs. Finally, he shows unusual audiologic and ophthalmologic signs nor previously reported as part of the 9p monosomy or 6p trisomy syndromes.     

胸腰段后髓动脉的起源及其临床意义

目的:为选择性脊髓血管造影和椎管内显微外科提供解剖学资料。方法:采用尸体标本30例,于节段性动脉内逐一注入红色乳胶,在完整脊髓上解剖观察。结果:每例脊髓胸腰段的后髓动脉数目5～13支,平均8.4支。后髓动脉起始情况分3型10亚型,其中后髓动脉与前髓动脉由同一肋间后动脉发出仅34支(13.5％)。胸下部及腰部后髓动脉呈典型“发卡”样折曲。后髓动脉平均外径0.37±0.12mm。约1/3标本在T_(11)～L_3间有1支后髓动脉较粗(>0.5mm),它是脊髓后下部血供的主要来源。结论:多数后髓动脉单独起始,较大的后髓动脉应引起注意。     

Tizanidine (DS103-282), a centrally acting muscle relaxant, selectively depresses excitation of feline dorsal horn neurones to noxious peripheral stimuli by an action at alpha 2-adrenoceptors

The effects of microiontophoretic ejection of tizanidine were compared with those of adrenoceptor agonists on responses of single laminae IV and V neurones to noxious and innocuous cutaneous stimuli. Tizanidine, noradrenaline and clonidine depressed neuronal responses to noxious but not innocuous stimuli. Spontaneous activity was also depressed by these three substances. By contrast, beta- and alpha 1-adrenoceptor agonists had no consistent effect on neuronal responses to cutaneous stimuli. The selective actions of tizanidine, noradrenaline and clonidine were reversibly antagonized by the alpha 2-adrenoceptor antagonist RX781094 but not by WB4101 (alpha 1 antagonist). The binding of an alpha 2-adrenoceptor ligand to rat brain membranes was preferentially displaced by tizanidine. These results indicate an interaction of tizanidine with central alpha 2-adrenoceptors.     

A selective effect of naloxone on heterosynaptic C-fibre-mediated inhibitions in the rat dorsal horn

The effect of naloxone on C-primary afferent-mediated inhibitions of C-fibre-evoked activity in deep dorsal horn neurones has been examined in decerebrate-spinal rats. The same C-afferents that evoke activity in a given neurone can inhibit that C-evoked activity (homosynaptic inhibition), and C-afferent input can also inhibit the activity evoked in dorsal horn neurones by other C-afferents (heterosynaptic inhibition). Naloxone was found to selectively reverse heterosynaptic C-mediated inhibitions without affecting homosynaptic inhibitions. In several neurones the heterosynaptic inhibitions were completely abolished by naloxone. These results show that homo- and heterosynaptic C-mediated inhibitions operate by different mechanisms and that, at least in some neurones, endogenous opioids are likely to be the major inhibitory transmitters involved in producing the heterosynaptic inhibition of the activity evoked by one C-input by another C-input.     

Generators of pathologically enhanced excitation as determinant structures in the spinal cord

With the aid of tetanus toxin, which disturbs various types of inhibition, generators of excitation were created in the left and right anterior horns of the lumbar spinal cord in rats. The regimes of activity of the generators differed: the left-sided generator, formed during the longer action of the toxin, in response to activation by trigger stimulation first produced tonic, and then intermittent activity, or individual spontaneous discharges, whereas the righ-sided generator produced only tonic activity. If one generator was blocked by glycine, the other continued to operate as before. Activation of one generator led to concomitant depression of the effects of the other. During separate activation of each generator, all the spinal and supraspinal motoneuron pools synchronously reproduced the character of activity of the generator functioning at that particular moment. The generator thus played the role of a determinant structure, determining the behavior of the system. The results are examined from the standpoint of the general concept of the role of determinant structures in the activity of the nervous system and the theory of generator mechanisms of neuropathological syndromes characterized by hyperactivity of systems.Laboratory of General Pathology of the Nervous System, Institute of General Pathology and Pathological Physiology, Academy of Medical Sciences of the USSR, Moscow. Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 5, pp. 515–519, May, 1977.     

豚鼠脊髓运动神经元分支至股神经和腰背肌的研究——逆行荧光双标记法

应用碘化丙院-双苯甲亚胺配伍逆行荧光双标记技术对豚鼠脊髓运动神经元分支至股神经和腰背肌作了研究.结果发现股神经的运动纤维来源于同侧L1～5脊髓前角内侧核运动神经元和L4～5脊髓前角外侧核运动神经元;腰背肌的运动纤维来源于同侧相应节段脊髓前角内侧核运动神经元.在L3～5脊髓前角内侧核运动神经元中,有碘化丙啶-双苯甲亚胺荧光双标记运动神经元,占内侧核全部标记运动神经元的18.8‰.结果提示脊髓前角运动神经元具有分支分布至腰背肌和股神经的现象.     

大鼠脊髓损伤后NGF及其受体TrkA在运动神经元及神经胶质细胞表达的变化

为探讨脊髓损伤后运动神经元及神经胶质细胞内神经生长因子(NGF)及其高亲和力受体(TrkA)表达的变化,用改良Allen重击法损伤SCI组动物T12脊髓,按伤后存活时间再将动物分为脊髓损1 d组、2 d组和5 d组。各组动物的脊髓切片经ABC法免疫组织化学染色,用光镜观察TrkA及NGF在脊髓前角运动神经元表达的变化和胶质纤维酸性蛋白(GFAP)及NGF免疫反应阳性胶质细胞的反应性增生程度,并进行图像分析。结果显示:脊髓损伤后前角运动神经元TrkA及NGF的表达随脊髓损伤后动物存活时间的延长逐渐上调;脊髓白质和灰质内尤其是皮质脊髓束内GFAP及NGF阳性胶质细胞明显增生;与此同时,室管膜细胞内亦可见明显的NGF免疫反应产物。上述结果表明,脊髓损伤可刺激脊髓前角运动神经元表达TrkA及NGF,通过自分泌维持受损神经元的存活;损伤部位反应性增生的胶质细胞亦可产生NGF,通过旁分泌作用于脊髓前角运动神经元或皮质脊髓束的轴突末梢,以维持运动神经元的存活及促进皮质脊髓束的再生;适时补充外源性神经营养素或改变损伤局部的微环境将有利于受损脊髓的修复和再生。