Classical conditioning, decay and extinction of cocaine-induced hyperactivity and stereotypy

Following 10 daily pairings of multiple conditioned stimuli with injection of cocaine (15 mg/kg), the presentation of the stimuli alone elicited behaviors in rats similar to those induced by cocaine. The behaviors included increased duration or frequency of rearing, sniffing, head bobbing, and horizontal locomotor activity (crossing). The level of the conditioned response for several of these behaviors approximated that induced by the drug itself. The conditioned drug effect showed decay over 15 days but little extinction during 4 daily trials. Brain concentrations of the dopamine metabolites, homovanillic acid and dihydroxyphenylacetic acid, were similar in the conditioned and pseudoconditioned control groups in both the caudate and mesolimbic areas. The behavioral results demonstrate that, in a classical conditioning paradigm, previously neutral stimuli can elicit behaviors similar to those induced by cocaine and that certain conditioned responses show time related decline. This agrees with the reported conditioning of amphetamine's behavioral effects but differs in terms of the action on brain dopamine turnover.     

我国微茎类吸虫研究:ⅩⅢ.微茎类吸虫成虫结构特征排序

对我国52种微茎类吸虫的18项成虫形态学特征进行主成分分析,结果表明:卵巢位置、子宫延伸位置等7项性状对第一主成分贡献较大,提示描述器官位置的指标是重要的分类依据。52个虫种在前三个主成分上的排序图显示应将其划分成4个亚科。     

柱萤叶甲属研究（Ⅰ）鞘翅具黑色刻点的种类记述（鞘翅目：叶甲科）

本文就萤叶甲亚科中柱萤叶甲属鞘翅具黑色刻点的种类进行研究,共记述４种,我国已记录３种,其中１种为新种。     

我国微茎类吸虫的研究Ⅻ.类茎属及多黄属二新种报道：复殖目：微茎科

本文报道在湛江市附近海域海鸟体内获得的两种吸虫,经鉴定为新种,命名为巨口类茎吸虫,新种Ｍｉｃｒｏｐｈａｌｌｏｉｄｅｓ ｍａｃｒｏｓｔｏｎｒｓ ｓｐ．ｎｏｖ．,珊瑚多黄吸虫,新种Ｍｕｌｔｉｖｉｔｅｌｌｕｓ ｃｏｒａｌｉｕｓ ｓｐ．ｎｏｖ．     

Correlation between cell cycle duration and RNA content.

The metachromatic fluorochrome acridine orange was used to differentially stain DNA and RNA in Chinese hamster ovary (CHO) cells and in mitogen-stimulated human lymphocytes during their progression through the cell cycle. Green and red fluorescence of individual cells, representing cellular DNA and RNA, respectively, was measured by flow cytometry. CHO cells were synchronized by selective detachment at mitosis. Their rate of progression through G1 and subsequently through S phase correlated with the content of stainable RNA. The mean duration of the G1 phase was 5.2 hours for cells with high RNA content (highest 25 percentile population) and 8.1 hours for cells with low RNA (lowest 25 percentile). The duration of S phase was 5.9 and 7.5 hours for high- and low-RNA, 25 percentile subpopulations, respectively. Lymphocytes synchronized at the G1/S boundary by hydroxyurea or 5-fluorodeoxyuridine showed extremely high intercellular variation with respect to content of stainable RNA. After release from the block they traversed S phase at rates linearly proportional to the content of stainable RNA. The duration of S phase was five hours for cells with high RNA-, six to nine hours for cells with moderate RNA- and up to 27 hours for cells with minimal RNA-content. The data suggest that the rate of progression through the cell cycle of individual cells within a population may be correlated with the number of ribosomes per cell.     

Different sensitivity of chromatin to acid denaturation in quiescent and cycling cells as revealed by flow cytometry.

The properties of DNA in situ as reflected by its staining with acridine orange are different in quiescent nonstimulated lymphocytes as compared with interphase lymphocytes that have entered the cell cycle after stimulation by mitogens. The difference is seen after cell treatment with buffers at pH 1.5 (1.3-1.9 range) followed by staining with acridine orange at pH 2.6 (2.3-2.9). Under these conditions the red metachromatic fluorescence of the acridine orange-DNA complex is higher in quiescent cells than in the cycling lymphocytes while the orthochromatic green fluorescence is higher in the cycling, interphase cells. The results suggest that DNA in condensed chromatin of quiescent lymphocytes (as in metaphase chromosomes) is more sensitive to acid-denaturation than DNA in dispersed chromatin of the cycling interphase cells. The phenomenon is used for flow cytometric differentiation between G0 and G1 cells and between G2 and M cells. In contrast to normal lymphocytes the method applied to neoplastic cells indicates the presence of cell subpopulations with condensed chromatin but with DNA content characteristic not only of G1 but also of S and G2 cells. The possibility that these cells represent quiescent (resting) subpopulations, arrested in G1, S and/or G2, is discussed.     

以化学纯饲料饲养北京的桃蚜

应用修改后的Dadd和Mitter(1966)全纯饲料配方配制成人工饲料饲养定居在北京温室烟草上的桃蚜 Myzus persicae可完成生活史井连续饲养3代。本文描述饲料配制、饲养和取食量测定的方法。这3代初羽化无翅孤雌胎生雌蚜的平均体重分别为:440±90.7μg,264±104.9μg和312±127.9μg。用放射性同位素稀释法测定取食量的结果得悉若虫期的总取食量每蚜约为1.74μg,相当于1.16μl。