通过MR扩散张量成像了解与年龄相关的豆状核变化

目的探讨MR扩散张量成像（DTI）观察豆状核年龄相关性变化的价值与意义。方法69名健康志愿者纳入本研究。入组对象按年龄分为3组：≤30岁（I）组，22例；31～50岁（Ⅱ）组，24例；〉50岁（Ⅲ）组，23例。利用DTI分别测量受试者大脑左右两侧壳核、苍白球的表观扩散系数（ADC）值、部分各向异性（FA）值及扩散张量特征值λ1、λ2、λ3。分析不同年龄组间ADC、FA、λ1、λ2、λ3值的差异及与年龄的相关性。结果I、Ⅱ、Ⅲ组的壳核ADC值分别为：（6．68±0．40）×10^-4、（6．47±0．36）×10^-4、（6．44±0．34）×10^-4mm^2／s，苍白球ADC值分别为：（6．13±0．50）×10^-4、（6．05±0．33）×10^-4、（6．05±0．52）×10$-4mm^2／s。I、Ⅱ、Ⅲ组的壳核FA值分别为：0．20±0．03、0．23±0．03、0．25±0．03，苍白球FA值分别为：0.35±0．03、0．36±0．03、0．37±0．04。各年龄组内壳核ADC值大于苍白球，而FA值小于苍白球。壳核FA值的组问差异有统计学意义（F=10．082，P=0.000），壳核I、Ⅱ、Ⅲ组入，值分别为（5．35±0．45）×10^-4、（5．04±0．46）×10^-4、（4．90±0．44）×10^-4mm^2／s，差异亦有统计学意义（F=5．675，P=0．005）；壳核FA值与年龄呈正相关（r=0．555，P〈0．01），λ3值与年龄呈负相关（r=-0.440，P〈0．01）。结论壳核FA值随年龄的增长而上升，λ3值随年龄的增长而下降。     

壬基酚对雄性大鼠弓状核神经元单位放电的影响

目的:探讨壬基酚对大鼠弓状核白发单位放电的影响。方法:染毒,将成年SD雄性大鼠用壬基酚灌胃染毒5周,建立壬基酚雄性大鼠模型作为实验组;对照组灌注等量花生油。模型建立后用玻璃微电极细胞外记录实验组和对照组大鼠弓状核冲经元自发放电。结果:壬基酚实验组大鼠弓状核神经元自发放电的形式以单个不匀为主(62．96％),而对照组则以单个不匀(31．6％)和混合型(43．0％)为主,组间差异有显著性(P＜0．05);实验组大鼠弓状核自发放电频率以低频(48．15％)和中频(44．44％)为主,对照组则以低频为主(58．23％),但组间差异无显著性(P＞0．05)。结论:壬基酚使大鼠弓状核自发单位放电发生了改变。     

Injections of dopaminergic, cholinergic, serotoninergic and GABAergic drugs into the nucleus accumbens: effects on locomotor activity in the rat

Locomotor activity was elicited by injecting dopamine into the nucleus accumbens of the chronically cannulated rat. Dopamine was also injected together with cholinergic, serotoninergic and GABAergic agonists and antagonists to investigate the possible contribution to locomotor activity of these putative neurotransmitters. Carbachol elicited a transient enhancement of dopamine-stimulated activity. Atropine attenuated carbachol-stimulated enhancement but did not attenuate dopamine-stimulated activity. Serotonin attenuated dopamine-stimulated activity. The peripheral serotonin antagonist, methysergide, also attenuated locomotion. The administration of GABA elicited a bimodal response in locomotion, the lower dose eliciting a small increase in locomotion and the larger dose eliciting a reduction. The GABA antagonist, picrotoxin, elicited only increases in locomotion at all doses. These results suggest that there is not a cholinergic interneuron on the dopamine-stimulated pathway subserving locomotion but that both cholinergic and serotoninergic projections may modulate locomotor activity. Further they suggest that such modulation must be at least one inhibitory interneuron away from the dopamine synapse on the locomotor pathway. In addition, these results suggest a direct influence of GABAergic interneurons on the pathway subserving locomotor activity within the nucleus accumbens.     

Circadian changes in arginine vasopressin level in the suprachiasmatic nuclei in the rat

Arginine vasopressin (AVP) neurons were preferentially localized in the dorsomedial part of the suprachiasmatic nucleus (SCN). To know the role of AVP neurons in the SCN, male rats were kept under a normal light-dark cycle (L-D), or under constant darkness (D-D) for 20 days. In L-D condition, AVP levels in the SCN showed the circadian change. In D-D condition, the patterns in AVP levels showed a free-running rhythm, and an about 12-h shift per 20 days. This result suggests that the activity of AVP neurons may be closely associated with the endogenous circadian rhythm of the SCN.     

术前放射治疗的探讨

目前恶性肿瘤的发病率越来越高,由于多种方法的综合治疗,使治愈率逐步提高,其中放射治疗的作用占相当重要的地位。其基本原理是当肿瘤细胞受照射时,正在进行核分裂的细胞几乎立即死亡,经过反复照射,肿瘤细胞就可完全被消灭。本文着重介绍术前放射治疗情况。