A learning deficit related to age and beta-amyloid plaques in a mouse model of Alzheimer's disease

Mice that overexpress the human mutant amyloid precursor protein (hAPP) show learning deficits, but the apparent lack of a relationship between these deficits and the progressive beta-amyloid plaque formation that the hAPP mice display is puzzling. In the water maze, hAPP mice are impaired before and after amyloid plaque deposition. Here we show, using a new water-maze training protocol, that PDAPP mice also exhibit a separate age-related deficit in learning a series of spatial locations. This impairment correlates with beta-amyloid plaque burden and is shown in both cross-sectional and longitudinal experimental designs. Cued navigation and object-recognition memory are normal. These findings indicate that A beta overexpression and/or A beta plaques are associated with disturbed cognitive function and, importantly, suggest that some but not all forms of learning and memory are suitable behavioural assays of the progressive cognitive deficits associated with Alzheimer's-disease-type pathologies.     

U-Pb zircon age for the Daohugou Biota at Ningcheng of Inner Mongolia and comments on related issues

SHRIMP U-Pb zircon dating was carried out for the Daohugou Biota near Ningcheng of Inner Mongolia and for lavas overlying or underlying sala-mander-bearing strata at Reshuitang in Lingyuan of West Liaoning. The results suggest that the Dao- hugou Biota occurred at an interval from 168 Ma to 164―152 Ma. Both the Daohugou Biota and the salamander-bearing fossil assemblage are the same biota and thus developed from 168 to 152 Ma, i.e. from late Middle Jurassic to the early Late Jurassic. The Daohugou Biota-bearing rocks, resting on the Jiulongshan Formation in disconformity and being overlain in unconformity by Late Jurassic Tuchengzi Formation and Early Cretaceous rocks containing the Jehol Biota, are mainly composed of volcanic-sedi- mentary rocks in a normal sequence. It is recom- mended that the Daohugou Biota and the related stratigraphy should be correlated with the Tiaojishan Formation (Lanqi Formation in West Liaoning) or its synchronous rocks. It is suggested that the Dao- hugou Biota and the Jehol Biota would be neither taken into one biota nor considered as the earliest elements of the Jehol Biota. The Daohugou Biota and the related rocks and the Yixian Formation were respectively formed in different periods of volcanic-sedimentary tectonics.     

PH值对应用肌球蛋白 ATP酶法进行梭内肌纤维分型的影响

探讨酸性和碱性预孵育处理，对应用肌球蛋白ATP酶法进行梭内肌纤维分型的影响。采用肌球蛋白ATP酶法。PH4．3和PH4．6预孵育液孵育后，梭内肌纤维中的核袋纤维染色呈阳性，核链纤维染色相对较浅；PH9．4预孵育后，核袋与核链纤维均呈阳性或强阳性；PH10．4预孵育后，核袋1纤维呈阴性，核袋2纤维呈阳性，核链纤维呈强阳性。结论是：用mATP酶法研究梭内肌纤维的分型时，预孵育液的PH值对分型结果有显著影响，应当说明并严格把握预孵育液的PH值。     

锁阳对小鼠耐力及骨骼肌抗氧化能力的影响

选用昆明种小鼠30只,随机分成运动组(Ⅰ)、运动 锁阳组(Ⅱ)进行实验.结果表明,运动 锁阳组小鼠力竭游泳时间明显长于运动组(P<0.01);血乳酸指数((mM/L)/游泳时间(min))和MDA含量明显低于运动组(P<0.05);小鼠的骨骼肌组织SOD、GSH-Px活力明显高于运动组(P<0.05).提示锁阳具有提高小鼠运动耐力和增强骨骼肌抗氧化酶活力的作用.     

水分、脂肪含量、蛋白质组成和肌肉纤维的大小对脆肉鲩鱼背肌质构特性的影响

通过对生脆肉鲩鱼背肌和生草鱼背肌的质构特性、水分含量、脂肪含量和蛋白质不同成分的测定,结合扫描电镜技术,研究水分、脂肪含量、蛋白质成分和肌肉纤维的平均大小对质构特性的影响。研究结果表明,脆肉鲩鱼肌肉的硬度、弹性、咀嚼性和回复性均比草鱼高,分别高出11.14%,3.4%, 15.75%和14.27%,但粘聚性比草鱼低16.16%。而脆肉鲩鱼的这些特征与其肌肉中的水分含量、基质蛋白的含量和肌肉纤维的平均直径与密度有关,特别是肌肉纤维的平均直径对脆肉鲩鱼肌肉的硬度影响更大,但是在本研究中脂肪含量对脆肉鲩鱼的硬度影响不大。     

S863天然果蔬饮料对力竭运动小鼠肝糖原、肌糖原含量及耐力的影响

实验以力竭游泳的小鼠为运动疲劳模型,将120只成年健康雄性小鼠随机分为5组:对照组、实验组、对照游泳组、实验游泳组、实验游泳3h组.通过测定各组小鼠肝糖原、肌糖原含量,探索S863天然果蔬饮料在提高肝脏和骨骼肌糖原储备、保证能量代谢的正常进行、提高耐力运动成绩、延缓运动疲劳的出现等方面的有效作用.实验结果表明:①实验游泳组小鼠的游泳时间,较对照游泳组明显延长(P<0 001).②实验组小鼠的肝糖原含量显著高于对照组(P<0 05);实验游泳3h组游泳180min无一例沉底,其肝糖原含量仍高于对照游泳组(P<0 05).③实验组小鼠的肌糖原含量均显著高于对照组(P<0 05);实验游泳3h组游泳180min后,其肌糖原含量仍高于对照游泳组(P<0 05).这些结果反映了S863天然果蔬饮料具有良好的营养价值,它能有效提高肝脏和骨骼肌糖原储备,利于能量代谢的正常进行,提高运动成绩.