猫小脑髓质胶质反应的年龄相关性变化

探讨青年猫和老年猫小脑髓质中胶质反应的年龄相关性变化及其意义。用改良的Holzer结晶紫染色显示所有胶质细胞,GFAP(胶质纤维酸性蛋白)免疫染色显示星形胶质细胞。光镜下对青年猫与老年猫小脑髓质中胶质细胞和GFAP免疫阳性(GFAP-IR)星形胶质细胞进行形态学观察和定量研究。与青年猫比较,老年猫小脑髓质中胶质细胞和GFAP-IR细胞密度均显著增加(P<0.01),胞体较大;GFAP阳性细胞阳性反应较强,突起稠密;星形胶质细胞占胶质细胞总数比例增加。这表明小脑髓质中胶质细胞随年龄增长明显增生,尤其星形胶质细胞具有明显的年龄相关性活动增强。提示胶质细胞及星形胶质细胞的增生可能对衰老的神经纤维起保护作用;星形胶质细胞对衰老较敏感。

猫小脑皮质GABA能神经元年龄相关性变化

为探讨青年猫和老年猫小脑皮质GABA能神经元及其表达的年龄相关性变化,利用Nissl染色显示小脑皮质结构及神经元,免疫组织化学ABC法标记GABA免疫阳性神经元。光镜下观察,采集图像,并利用图像分析软件对分子层、蒲肯野细胞层和颗粒层神经元及GABA免疫阳性神经元及其灰度值进行分析统计。结果显示,GABA免疫阳性神经元、阳性纤维及终末在青年猫和老年猫小脑皮质各层均有分布。与青年猫相比,老年猫分子层、蒲肯野细胞层神经元和GABA免疫阳性神经元密度及其GABA免疫阳性反应强度均显著下降(P<0.01),颗粒层神经元密度和GABA免疫阳性强度也显著下降(P<0.01),但其GABA免疫阳性神经元密度无显著变化(P>0.05);蒲肯野细胞的胞体萎缩,阳性树突分枝减少。因此认为,衰老过程中猫小脑皮质GABA能神经元的丢失和GABA表达的下降,可能是老年个体运动协调、精确调速和运动学习等能力下降的重要原因之一。

Predisposing factors for atrial fibrillation in the elderly

Atrial fibrillation （AF） in the elderly occurs as a consequence of cardiovascular aging and an age related increase of comorbidity. Several predisposing factors for AF have been identified for the overall AF population. Most of them, cardiovascular disease in particular, play a role in younger and older patients. The longer time period during which these risk factors can cause structural changes that ultimately lead to AF may, at least in part, explain the association between age and AF. In addition, less well defined age-related changes in cellular electrophysi- ologic properties and structure predispose to AF in the elderly.