Pictorial gaze cues do not enhance long-tailed macaques' performance on a computerised object-location task

The perception of pictorial gaze cues was examined in long-tailed macaques (Macaca fascicularis). A computerised object-location task was used to explore whether the monkeys would show faster response time to locate a target when its appearance was preceded with congruent as opposed to incongruent gaze cues. Despite existing evidence that macaques preferentially attend to the eyes in facial images and also visually orient with depicted gaze cues, the monkeys did not show faster response times on congruent trials either in response to schematic or photographic stimuli. These findings coincide with those reported for baboons testing with a similar paradigm in which gaze cues preceded a target identification task [Fagot, J., Deruelle, C., 2002. Perception of pictorial gaze by baboons (Papio papio). J. Exp. Psychol. 28, 298-308]. When tested with either pictorial stimuli or interactants, nonhuman primates readily follow gaze but do not seem to use this mechanism to identify a target object; there seems to be some mismatch in performance between attentional changes and manual responses to gaze cues on ostensibly similar tasks.     

扬子鳄中脑视叶NOS、AChE阳性神经元的分布

目的观察扬子鳄中脑视叶一氧化氮合酶(nitric oxide synthase,NOS)和乙酰胆碱酯酶(acetylcholinesterase,AChE)阳性神经元的形态和分布,为扬子鳄脑的比较解剖学积累资料,为其机能研究提供形态学依据。方法采用还原型尼克酰胺腺嘌呤二核苷酸黄递酶(NADPH-d)法和亚铁氰化酮法观察扬子鳄中脑视叶NOS和AChE阳性神经元的分布和特征,并作统计学处理。结果扬子鳄中脑视叶有NOS和AChE阳性神经元分布,为大、中、小型细胞,以中、小型细胞为主,胞体呈椭圆形、三角形、圆形和梭形。结论扬子鳄中脑视叶有NOS和AChE阳性神经元分布。     

扬子鳄梨状皮质NOS、AChE阳性神经元的分布

目的观察扬子鳄梨状皮质内一氧化氮合酶(nitric oxide synthase,NOS)和乙酰胆碱酯酶(acetylcho-linesterase,AChE)阳性神经元的形态和分布,为扬子鳄脑的比较解剖学积累资料,为其机能研究提供形态学依据。方法采用还原型尼克酰胺腺嘌呤二核苷酸黄递酶(NADPH-d)法和亚铁氰化酮法观察扬子鳄梨状皮质内NOS和AChE阳性神经元的分布和特征。结果扬子鳄梨状皮质内有NOS和AChE阳性神经元分布,为大、中、小型细胞,以中小型细胞为主,胞体呈圆形、椭圆形、三角形和梭形。结论扬子鳄梨状皮质内有NOS和AChE阳性神经元分布。     

Gas7在大鼠海马和齿状回发育过程中的动态表达

目的研究生长休止蛋白7（Gas7）在大鼠海马和齿状回不同发育阶段的表达。方法采用免疫组织化学方法观察Gas7在SD大鼠胚胎第18d（E18）、新生（P0）、生后第7d（P7）、P14、P21和成年海马和齿状回中的表达和分布。结果在大鼠脑海马和齿状回部位的冠状切片上,Gas7免疫反应阳性产物主要表达在海马的锥体细胞、齿状回的颗粒细胞和门区的多形层细胞。随着发育的进程,在海马,Gas7较早表达在CA3区,其次是CA2和CA1区;在齿状回,Gas7在外臂的表达早于内臂,在颗粒细胞层的表达是按先外层后内层的顺序。在围生期,Gas7在海马和齿状回各区的表达逐渐增强,至P14达到高峰,后逐渐降低,至P21其表达强度和分布趋于恒定至成年水平。结论 Gas7在大鼠海马和齿状回发育过程中的动态表达具有时间和空间上的特异性,提示Gas7可能参与了海马和齿状回形态形成和功能成熟的调控。     

A Novel Chordoma Xenograft Allows In Vivo Drug Testing and Reveals the Importance of NF-κB Signaling in Chordoma Biology

Chordoma is a rare primary bone malignancy that arises in the skull base, spine and sacrum and originates from remnants of the notochord. These tumors are typically resistant to conventional chemotherapy, and to date there are no FDA-approved agents to treat chordoma. The lack of in vivo models of chordoma has impeded the development of new therapies for this tumor. Primary tumor from a sacral chordoma was xenografted into NOD/SCID/IL-2R γ-null mice. The xenograft is serially transplantable and was characterized by both gene expression analysis and whole genome SNP genotyping. The NIH Chemical Genomics Center performed high-throughput screening of 2,816 compounds using two established chordoma cell lines, U-CH1 and U-CH2B. The screen yielded several compounds that showed activity and two, sunitinib and bortezomib, were tested in the xenograft. Both agents slowed the growth of the xenograft tumor. Sensitivity to an inhibitor of IκB, as well as inhibition of an NF-κB gene expression signature demonstrated the importance of NF-κB signaling for chordoma growth. This serially transplantable chordoma xenograft is thus a practical model to study chordomas and perform in vivo preclinical drug testing.     

Kinetic studies of human immunodeficiency virus type 1 protease and its active-site hydrogen bond mutant A28S.

Human immunodeficiency virus type 1 (HIV-1) protease optimally catalyzes in the pH range of 4-6 in contrast to nearly all of the other eukaryotic aspartic proteases, which catalyze best in the pH range of 2-4. A possible structural reason for the higher optimal pH of HIV-1 protease is the absence of a hydrogen bond to the carboxyl group of active-site Asp25, which is nearly universally present in others. To investigate this hypothesis, we have mutated residue 28 in HIV-1 protease from alanine to serine. Both the wild-type and the mutant A28S enzymes have been overexpressed in Escherichia coli using a chemically synthesized gene and purified for a comparative study in enzyme kinetics. The kcat and Km values were determined by a radiometric assay for the wild-type enzyme from pH 3.2 to 7.0, and for the mutant enzyme from pH 3.2 to 6.0. The low pK values of the active site of the free enzyme, pKe1, are 3.3 and 3.4 for the wild-type and mutant enzymes, respectively. The low pK values of the active site of the enzyme bound to substrate, pKes1, are 5.1 and 4.3 for the wild-type and mutant enzymes, respectively. The high pK values of the free enzyme, pKe2, are 6.8 and 5.6, and the corresponding ones for the substrate-bound enzyme, pKes2, are 6.9 and 6.0 for the wild-type and mutant enzymes, respectively. The lowering of pK values in mutant HIV-1 protease indicates that the hydroxyl group of Ser28 forms a new hydrogen bond to active-site Asp25 to increase its acidity.