胸腰脊神经根鞘形态观测及其临床意义

目的：为了探讨腰腿疼痛等疾病与脊神经根鞘的关系。方法：用巨视解剖和游标卡尺测量法对１５具尸体的胸腰脊神经根鞘进行了解剖学观察与测量。结果：①左、右胸腰脊神经根鞘长度和横径基本对称；②Ｔ１根鞘长度和横径大于其它胸神经根鞘，接近Ｌ２水平，Ｌ３～Ｌ５根鞘长度和横径大于其它胸腰神经根鞘，尤其Ｌ５更为突出；③胸腰脊神经根鞘开口式，由上向下，由２～３孔逐渐减至１孔。结论：①Ｔ１、Ｌ２～Ｌ５脊神经根鞘既长又粗，与周围接触范围大，受损危险增大；②根鞘开口式孔数由上向下减少，发生在鞘内的炎症和肿瘤引起前、后根同时受累的机会增多。     

带翼金属烤瓷冠在残根残冠修复中的应用

目的 保留根周健康的残冠残根，采取带翼金属烤瓷冠修复牙体缺损，以恢复功能及美观。方法 选择85例患者110颗患牙经过根管治疗，给予金属烤瓷冠修复，修复时在它的邻牙腭或舌侧设计金属翼以加强固位。结果 经1～5年观察修复效果良好。结论 带翼金属烤瓷冠增加了唇、颊向对抗力，并分散了残根的垂直耠力，加强了摩擦力及固位。临床观察，具有一定实用性和可行性，但远期效果有待进一步探讨。     

Bicuculline-induced circling from the rat superior colliculus is blocked by GABA microinjection into the deep cerebellar nuclei

In a recent electrophysiological experiment, we showed the deep cerebellar nuclei to be a major source of excitatory input to the superior colliculus. Furthermore, target neurons in the colliculus were found, in every case, to receive convergent tonic inhibitory input from the substantia nigra pars reticulata. In the present study, we investigated these effects in the awake rat. We asked whether circling behaviour, induced by unilateral injection of a GABA antagonist into the lateral colliculus, could be suppressed by concurrent cerebellar inactivation. Rats were chronically implanted with bilateral guide cannulae located above the superior colliculus and deep cerebellar nuclei. Bicuculline methiodide (25 pmol) was microinjected unilaterally into intermediate layers of the colliculus at increasing depths until an optimal contralateral circling response was elicited. This behaviour was taken as the baseline response and was the first of three treatments. The second was an identical manipulation of the colliculus with a concurrent 200-nl microinjection of 1 M GABA into the contralateral deep cerebellar nuclei. The third was a repeat of BIC alone into the colliculus or, if rotation had been suppressed by more than 50% on test 2, the treatment was collicular BIC plus deep cerebellar saline. This latter treatment was used as a control for possible non-pharmacological injection effects. The effect of cerebellar GABA at 26 sites (17 within cerebellar nuclei and 9 outside) on BIC-induced rotation at 15 collicular sites was studied in ten animals. Only GABA injections at sites that fell within the cerebellar nuclei significantly reduced turning (P<0.0001). A full behavioural analysis showed that this was a specific suppression of turning, not the result of general motor impairment. These results provide clear behavioural evidence that opposing, convergent influences from the basal ganglia and cerebellum interact in the lateral superior colliculus to control head and body movements. They furthermore suggest that the tonic deep cerebellar excitation of the superior colliculus could be the driving force in the expression of rotation induced by manipulations of the basal ganglia.     

亮氨酸脑啡肽样和P物质样免疫反应物在大鼠延髓迷走神经背核簇和网状结构内的分布

用PAP法研究亮氨酸脑啡肽样(L—ENK—LI)和P物质样(SP—LI)免疫反应物在大鼠延髓迷走神经背核簇和网状结构内的分布。证明在孤束核、迷走神经背核、外侧网状核外侧部及其外侧的区域内有大量的L-ENK样终末和纤维,在背侧和腹侧网状核之间的移行区内有中等量的分布,其余区内为少量。L-ENK样胞体在孤束核、咀侧腹外侧网状核、巨细胞网状核的腹侧部和α部、外侧旁巨细胞核以及中缝大核内均有许多分布,在迷走神经背核的尾侧部、背侧和腹侧网状核之间的移行区有中等量,其余区内为少量。SP样反应物的分布与L-ENK样物类似,但其终末和纤维的数量较L-ENK者略少,阳性胞体的数量除了在中缝核及外侧旁巨细胞核内侧端中的量较L-ENK样胞体多以外,在其余区内均较少。     

A role for the basal ganglia in nicotinic modulation of the blink reflex

Summary In humans and rats we found that nicotine transiently modifies the blink reflex. For blinks elicited by stimulation of the supraorbital branch of the trigeminal nerve, nicotine decreased the magnitude of the orbicularis oculi electromyogram (OOemg) and increased the latency of only the long-latency (R2) component. For blinks elicited by electrical stimulation of the cornea, nicotine decreased the magnitude and increased the latency of the single component of OOemg response. Since nicotine modified only one component of the supraorbitally elicited blink reflex, nicotine must act primarily on the central nervous system rather than at the muscle. The effects of nicotine could be caused by direct action on lower brainstem interneurons or indirectly by modulating descending systems impinging on blink interneurons. Since precollicular decerebration eliminated nicotine's effects on the blink reflex, nicotine must act through descending systems. Three lines of evidence suggest that nicotine affects the blink reflex through the basal ganglia by causing dopamine release in the striatum. First, stimulation of the substantia nigra mimicked the effects of nicotine on the blink reflex. Second, haloperidol, a dopamine (D₂) receptor antagonist, blocked the effect of nicotine on the blink reflex. Third, apomorphine, a D₂ receptor agonist, mimicked the effects of nicotine on the blink reflex.     

Immunoreactive somatostatin-28(1-12) is increased in Huntington's disease

Somatostatin-28(1-12) concentrations were measured in Huntington's disease (HD) postmortem tissue using a specific radioimmunoassay. Concentrations of immunoreactive somatostatin-28(1-12) were significantly increased in the caudate and putamen but were unchanged in cortical areas A9 and A17. Since somatostatin-28(1-12) terminates with the amino acids Arg-Glu-OH, we examined whether this dodecapeptide compound might exert a neurotoxic effect. Injections of somatostatin-28(1-12) into rat striatum showed no evidence of histologic damage.     

Median frequency of the myoelectric signal

Summary A study was performed to investigate the changes that occur in the median frequency of the myoelectric signal during local ischemia or reduction of intramuscular temperature produced by surface cooling. Data was obtained from experiments which involved the first dorsal interosseous muscle of 10 female and 16 male subjects. These subjects were asked to perform isometric constant-force abduction contractions of the index finger at 20% and 80% of maximal voluntary contraction level. The initial median frequency (IMF) of the myoelectric signal during the first 0.5 s of contraction was calculated. Results showed a significant reduction of the IMF in contractions performed under ischemic conditions; upon release, the IMF recovered quickly. At 80% maximal voluntary level of contraction, a greater decrease of the IMF was recorded. Similar results were demonstrated during reduction of intramuscular temperature with gradual recovery of the IMF after cooling. These results demonstrate that the median frequency of the myoelectric signal displays behavior similar to that reported for conduction velocity and this is consistent with the notion that accumulation of metabolic byproducts in muscle tissue causes a decrease in the conduction velocity of the muscle fibers.Dr. R. Merletti was on a leave of absence from the Institute of Electrical Engineering, Politecnico di Torino, Italy     

胸腰脊神经后根形态计量研究

在15具成人尸体上对胸腰脊神经后根进行了大体解剖和形态计量研究.结果表明:(1)上胸段脊神经后根的囊外段长度、硬膜点横径和脊髓点束数在逐节减少;后根的囊外段与囊长轴之下夹角>90°,囊内段及脊髓点分布长度在逐节增加,交通支最丰富.(2)中胸段脊神经后根的囊外段长度、硬膜点横径和脊髓点束数各节段波动范围较小,下夹角在90°左右,囊内段短,脊髓点分布长.(3)下胸段脊神经后根的脊髓点分布长度转而下降,下夹角<90°,其它指标均逐节增加.(4)腰段脊神经后根的脊髓点分布长度进一步减少,下夹角最小,其它指标达最大值,交通支丰富.根据研究结果进行后根受损危险排序,腰>下胸>上胸>中胸.