活细胞计数试剂盒在检测5-氮杂-2’-脱氧胞苷对慢性粒细胞白血病细胞的增殖抑制作用中的应用

目的探讨活细胞计数试剂盒(CCK-8)在检测5-氮杂-2’-脱氧胞苷(5-Aza-2’-dc)对慢性粒细胞白血病细胞的增殖抑制作用中的应用。方法采用CCK-8检测不同浓度5-Aza-2’-dc对K562细胞的增殖抑制作用,并检测其半数抑制浓度对K562细胞的细胞周期和凋亡的影响。结果 5-Aza-2’-dc的半数抑制浓度为15.55nmol/L,采用该浓度处理K562细胞后,G2期发生阻滞,增殖抑制,并出现凋亡峰。结论不同浓度的5-Aza-2’-dc对K562细胞增殖的抑制作用不同,且呈浓度依赖关系。CCK-8检测法可运用于甲基化转移酶抑制剂对人慢性粒细胞白血病细胞增殖的影响。     

Autophagy inhibition switches low-dose camptothecin-induced premature senescence to apoptosis in human colorectal cancer cells

Recently, several studies indicated that senescent tumor cells are resistant to apoptosis in chemotherapy. They may return to cell cycle, thus act as stumbling blocks in anticancer treatments. In the present study, we found that, in human colorectal cancer cells, low-dose camptothecin (CPT) simultaneously induced autophagy and premature senescence through AMPK-TSC2-mTOR pathway and ATM-Chk2-p53-p21 pathway respectively. What's important is the suppression of autophagy substantially increased apoptosis and greatly attenuated senescence possibly by blocking p53/p21 pathway, which suggests that autophagy plays an indispensable role in sustaining cell senescence caused by low-dose CPT. The combination of low-dose CPT and autophagy inhibitor, a way to lead senescent cells to die, would be potentially valuable in cancer therapy.     

α、β放射性测量中计数效率与取样量的关系

目的分析α、β放射性测量中计数效率与取样量的关系,以便在α、β放射性测量中使用准确的计数效率进行计算。方法以50—250mg标准物质粉末,制备成标准源系列,分别进行计数效率测定,用SPSS软件的曲线估计功能分析计数效率和取样量之间可能的曲线关系,选择拟合程度高且便于使用的拟合曲线模型作为计数效率与取样量之间的曲线关系。同时研究不同通道之间的差异。结果同一通道d计数效率与取样量对数曲线、二次曲线和三次曲线相关性较高,r方值大于等于0．995,对于不同通道,其拟合曲线方程不同;同一通道β计数效率不受取样量的影响,50-250mg标准物质粉末,在同一通道β计数效率的相对标准偏差为2．9％～5．9％;对于不同通道,其β计数效率均值不同。结论进行α放射性测量时,对于同一通道,可以以取样量对α计数效率作对数曲线、二次曲线或三次曲线,由曲线方程求得50～250mg取样量对应的α计数效率作为该样品的仪计数效率,其中建立对数曲线较为简便,建议首选对数曲线,对于不同通道,其拟合曲线方程不同,应分别进行拟合;进行β放射性测量时,可采用同一通道β计数效率均值作为该样品的β计数效率;对于不同通道,其β计数效率均值不同,应分别进行计数效率校正。     

Spatial and numerical abilities without a complete natural language

We studied the cognitive abilities of a 13-year-old deaf child, deprived of most linguistic input from late infancy, in a battery of tests designed to reveal the nature of numerical and geometrical abilities in the absence of a full linguistic system. Tests revealed widespread proficiency in basic symbolic and non-symbolic numerical computations involving the use of both exact and approximate numbers. Tests of spatial and geometrical abilities revealed an interesting patchwork of age-typical strengths and localized deficits. In particular, the child performed extremely well on navigation tasks involving geometrical or landmark information presented in isolation, but very poorly on otherwise similar tasks that required the combination of the two types of spatial information. Tests of number- and space-specific language revealed proficiency in the use of number words and deficits in the use of spatial terms. This case suggests that a full linguistic system is not necessary to reap the benefits of linguistic vocabulary on basic numerical tasks. Furthermore, it suggests that language plays an important role in the combination of mental representations of space.     

Attention during active visual tasks: counting, pointing, or simply looking

Visual attention and saccades are typically studied in artificial situations, with stimuli presented to the steadily fixating eye, or saccades made along specified paths. By contrast, in real-world tasks saccadic patterns are constrained only by the demands of the motivating task. We studied attention during pauses between saccades made to perform three free-viewing tasks: counting dots, pointing to the same dots with a visible cursor, or simply looking at the dots using a freely-chosen path. Attention was assessed by the ability to identify the orientation of a briefly-presented Gabor probe. All primary tasks produced losses in identification performance, with counting producing the largest losses, followed by pointing and then looking-only. Looking-only resulted in a 37% increase in contrast thresholds in the orientation task. Counting produced more severe losses that were not overcome by increasing Gabor contrast. Detection or localization of the Gabor, unlike identification, were largely unaffected by any of the primary tasks. Taken together, these results show that attention is required to control saccades, even with freely-chosen paths, but the attentional demands of saccades are less than those attached to tasks such as counting, which have a significant cognitive load. Counting proved to be a highly demanding task that either exhausted momentary processing capacity (e.g., working memory or executive functions), or, alternatively, encouraged a strategy of filtering out all signals irrelevant to counting itself. The fact that the attentional demands of saccades (as well as those of detection/localization) are relatively modest makes it possible to continually adjust both the spatial and temporal pattern of saccades so as to re-allocate attentional resources as needed to handle the complex and multifaceted demands of real-world environments.     

活性乳酸菌制品中乳酸菌计数条件的优化研究

[目的]探索一种乳酸菌计数的选择性培养基,真实反映产品中乳酸菌的数量。[方法]用涂布法和平板倾注法,在不同的培养条件对计数结果进行对比研究。[结果]在改良TJA培养基中加入硫酸多粘菌素10万IU／L和放线菌酮10mg／L(双抗-TJA培养基),双抗-TJA培养基可抑制样品中可能污染的杂菌,对乳酸菌无影响。[结论]乳酸菌计数的优化条件为：用平板涂布法,在CO2烛缸法条件下培养48h。该实验可最大限度地检出样品中的乳酸菌数量,且条件简单,方法易掌握,结果准确,易于推广使用。     

Influence of beliefs about heart rate and actual heart rate on heartbeat counting

The heartbeat counting task is used widely to assess the ability to perceive cardiac sensations. However, performance on this task may be determined by processes other than sensitivity to cardiac stimuli. Beliefs about the effects of postural and exercise challenges on heart rate were assessed by questionnaire prior to performing the heartbeat counting task, and then actual heart rate was manipulated during the counting task by changes in posture and exercise. On average, counted heart rates were closer to beliefs about heart rate than to actual heart rate. Hierarchical multiple regression analyses indicated that (a) believed heart rates predicted counted heart rates while controlling for actual heart rates and (b) actual heart rates also predicted counted heart rate while controlling for heart rate beliefs. These data suggest that the rate of heartbeat counting is influenced by beliefs about heart rate and by the processing of cardiac sensations.     

Malingering detection in a Spanish population with a known-groups design

Malingering detection has become a topic of increased interest in the US over the last years. However, this development has not been matched in Europe. For example, in Spain there is insufficient evidence to support the use of reliable and valid malingering tests. In this study, we tested the applicability of two malingering detection tests (Test of Memory Malingering (TOMM) and Dot Counting Test) in a Spanish sample. The sample included three groups of patients (30 non-compensation seeking, 14 compensation seeking non-suspected of malingering, and 10 suspected of malingering) and a group of analog students (n = 54). Tests’ results were able to discriminate between the groups of malingerers (both patients and analogs) and non-malingerers (both compensation seeking and non-compensation seeking). However, the TOMM achieved a higher overall classification rate than the Dot Counting Test. Our results encourage the use of the TOMM as an indicator of malingering with Spanish population.     

药品检验用市售玫瑰红钠琼脂培养基质量研究

研究中国药品检验用玫瑰红钠琼脂培养基整体质量水平,为《中国药典》等药品质量标准的修订提供技术支持。方法：使用4个质控菌对国内外7家培养基生产商的玫瑰红钠琼脂培养基进行质量评价。结果：不同培养基的pH存在差异。7个生产商的培养基对白色念珠菌和黑曲霉的生长率均大于0．7,生长率均值差异无统计学意义（P〉0．05）。7个培养基和对照培养基对金黄色葡萄球菌的选择因子均大于6;8个培养基产品对大肠埃希菌的选择因子表现出差别,A、B、C、E、G和对照培养基无抑制性（选择性）;D和F表现出一定选择性。结论：不同厂家的药品检验用玫瑰红钠琼脂培养基的促生长能力表现一致;不同厂家产品的pH和对大肠埃希菌的选择性存在差异。