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。     

Synaptic actions of the ventral root afferents on cat hindlimb motoneurons

Postsynaptic potentials (PSPs) with long latencies were evoked in cat hindlimb motoneurons by stimulation of the distal stump of a cut ventral root. Measurements of their latency and the threshold in the responsible afferent fibers showed that they were produced mainly by the activity of the unmyelinated fibers in the ventral root that enter the spinal cord through the dorsal root. Patterns of PSPs evoked in flexor and extensor motoneurons by ventral root stimulation were similar to those observed in the flexion reflex.     

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。     

胰岛淀粉样多肽和甲硫氨酸-脑啡肽在家兔和大鼠背根神经节细胞内共存的免疫组织化学研究

为进一步探讨背根神经节细胞间生物活性物质内的关系，用免疫组织化学ＡＢＣ法，观察到家兔和大鼠背根神经节细胞内有胰岛淀粉样多肽免疫反应。用相邻镜像邻片免疫双标记技术，证实甲硫氨酸－脑啡肽免疫反应的细胞内同时含有胰岛淀粉样多肽免疫反应物质。胰岛淀粉样多肽与甲硫氨酸－脑啡肽在哺乳类动物背根神经节细胞内的共存结果，为进一步探讨背根神经节细胞内生物活性物质间的关系提供了形态学证据，并为胰岛淀粉样多肽的胰腺外研究提供了新的资料。     

Effects of picrotoxin on potassium accumulation and dorsal root potentials in the frog spinal cord.

The effects of picrotoxin on the changes of extracellular potassium concentration (Δ[K⁺]_e), field potentials and dorsal root potentials evoked by afferent stimulation, were studied in the isolated spinal cord of the frog. Δ[K⁺]_e was measured with potassium selective micro-electrodes. In a normal Ringer's solution the Δ[K⁺]_e evoked by a single pulse applied to a dorsal root did not exceed 0.05 mM. In solutions containing picrotoxin (10^?7?10^?5m) the Δ[K⁺]_e increased to 0.06–0.1 mm. At higher concentrations (10^?4?10^?3m) of picrotoxin the Δ[K⁺]_e reached 3–6 mm and spontaneous elevations of [K⁺]_e were observed synchronously with the dorsal root potentials. The latter were depressed by 20–40% and considerably prolonged. The time constant of their ascending phase increased from 9 to 10 ms to 30–40 ms. The second component of the negative field potential, recorded from the intermediate region, increased and its time course corresponded to that of the evoked dorsal root potentials. Impulse activity of motoneurones and interneurones evoked by afferent stimulation was greatly enhanced. Picrotoxin (10^?4?5.10^?4m) was found to have no effect on the ‘asynaptic’ component of evoked dorsal root potentials, which is resistant to 20 mm MgSO₄ and to the absence of Ca²⁺. It is therefore unlikely that the depressant effect of picrotoxin on the evoked dorsal root potentials is produced by its direct action on the potassium conductance of primary afferents.The findings are consistent with a dual mechanism of dorsal root potentials. The fast component of evoked dorsal root potentials which is depressed by picrotoxin is apparently produced by activation of axo-axonic synapses at the primary afferents, while the slow component is due to transient accumulation of extracellular K⁺. The potassium component of the evoked dorsal root potentials becomes dominant in solutions with high concentrations of picrotoxin (10^?4?10^?3m) when impulse transmission is greatly enhanced.     

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.     

下颌第一前磨牙根管系统和根尖孔解剖及临床意义

采用牙髓透明法对 347颗下颌第一前磨牙根管系统的数目和形态进行观察。下颌第一前磨牙根管可分为Ⅰ、Ⅱ、Ⅲ、Ⅳ型。其中Ⅰ型 (单根单管型 )占 83 86 % ,Ⅱ型 (单根双管型 )占 4 6 1% ,Ⅲ型 (单双管混合型 )占 11 2 4 % ,Ⅳ型 (双根双管型 )占 0 2 9%。应用XTT— 3A连续变倍体视显微镜对 347颗下颌第一前磨牙的根管系统形态进行观察 ,根尖分歧出现率 15 6 3% ,根尖分叉出现率 2 4 3% ,根管侧支出现率 1 0 8%。并对 347颗下颌第一前磨牙的根尖孔与根尖顶的位置关系进行观察 ,根尖孔位于根尖顶者占 88 14 % ,位于旁侧者占 11 86 %。并就上述内容的临床意义进行了讨论。     

鸡后根神经节多巴胺细胞在体及体外培养中的免疫细胞化学观察

应用免疫细胞化学PAP法,研究了鸡胚和雏鸡后根神经节细胞内多巴胺递质的表现与胚胎发育过程中的变化,并在细胞培养条件下研究了周围靶组织——皮肤对后根节细胞胚胎发育的影响。鸡后根节细胞内多巴胺的免疫反应最先出现于E_(10),只占后根节细胞的0.8%,E_(18)时达5.6%,出壳后雏鸡为8.6%。在鸡后根节内,多巴胺免疫反应阳性细胞主要为较大的A类细胞,和极少较小的B类细胞。免疫反应阳性的周围神经末梢位于皮肤和交感干内。当取自E_9的鸡胚后根节细胞经7天培养后,部分神经细胞出现多巴胺免疫反应阳性;而取自E_6的鸡胚后根节细胞虽经10天培养后仍为免疫反应阴性;然而,将取自E_6后根节细胞与皮肤组织联合培养10天后,少量神经细胞及轴突出现多巴胺免疫阳性反应。作者认为:鸡后根节多巴胺细胞在胚胎时期的发育有赖于周围靶组织的作用。     

非悬滴开放式培养法在鸡胚背根节体外培养中的应用

本研究针对悬滴培养法在操作和应用上存在的问题和局限性，改用操作简便、适用范围广的非悬滴开放式培养法培养鸡胚背根节。将数个鸡胚背根节按一定间隔种植在内置生长基质盖玻片的35mm培养皿中，加人适量培养液，置于CO2。孵箱中进行培养。结果显示.从培养24h至60h各时期，培养皿中背根节生长状况均良好，神经突起明显增长，表明用非悬滴开放式培养法培养鸡胚背根节是可行且可靠的。