赤子爱胜蚓对镉、铅富集作用的初探

用ρPb2＋和ρCd2＋分别为25.0,50,0,100.0,200.0,400.0mg/L的溶液及二者的混合溶液对蚯蚓进行急性毒性实验,经2,4,6,8,10,12d染毒处理后,用原子吸收分光光度计测定镉、铅在蚯蚓体内的富集量.结果表明：在实验剂量范围内,镉、铅的富集量随染毒时间的延长而增加,随着浓度的增大而增加,呈剂量效应变化.不同浓度的镉、铅胁迫下,蚯蚓对镉或铅富集的量与富集速率各不相同.蚯蚓对铅的富集量远远大于镉.表明蚯蚓可用于环境重金属污染监测和净化环境重金属污染.     

益气活血方对早期糖尿病肾病大鼠肾脏相关指标的影响

目的：探析益气活血方对早期糖尿病肾病大鼠肾脏PKC、TGF-β1及血清Chol、TG等指标的影响。方法：选择糖尿病肾病造模成功的64只SD大鼠,随机分为空白对照组(11只)、依那普利组11只、益气活血方大剂量组(观察组1,14只)、益气活血方中剂量组(观察组2,14只)、益气活血方小剂量组(观察组3,14只),并选择11只健康SD大鼠作为正常组。比较与分析各组大鼠的血清TG、Chol水平以及大鼠肾组织PKC、TGF-β1指标表达情况。结果：DN空白对照组大鼠的血清TG、Chol水平、肾组织PKC、TGF-β1表达均明显高于正常组、依那普利组以及益气活血方组。其中,益气活血方组的三个剂量组均可显著降低血清TG、Chol水平、肾组织PKC、TGF-β1表达等,尤以大剂量组的效果最优。结论：益气活血方可以有效缓解肾小球纤维化病变,从而有效保护肾脏。     

Pb~(2+)对草鱼鱼种肾脏和鳃Na~+/K~+-ATPase活性的影响

采用静态染毒法研究了不同质量浓度的铅离子胁迫下,暴露24,48,72,96h后对草鱼(Ctenopharyngodonidellus)鱼种肾脏和鳃组织中Na+/K+-ATPas活性的影响.结果表明:Pb2+对草鱼鱼种的肾脏、鳃组织Na+/K+-ATPase的活性有抑制作用.且具有时间和浓度效应,即随Pb2+胁迫时间的延长和浓度的升高而下降.Pb2+对草鱼鱼种肾脏Na+/K+-ATPase活性的抑制作用较鳃组织明显,Na+/K+-ATPase可作为一种很有潜力的环境污染效应的生物标志物.     

铅中毒侵害儿童健康

去年以来,在北京儿童医院连续掀起血铅检测高潮。全国各地的许多家长利用节假日专程带孩子到北京检测血铅浓度。为此,记者赴北京采访了北京儿童医院保健科的张峰主任。张主任告诉记者,血铅浓度过高在目前的城市儿童身上普遍存在。随着工业化程度的加深,环境污染加重,空气中、生活用品中铅的含量都大大提高,如汽车尾气,儿童玩具及学习用品的油漆层都含有大量的铅。儿童由于肾、消化道等器官尚未发育健全,在高铅的环境中长期生活,就会发生一定程度的铅中毒。     

8-羟基喹啉经口灌胃对小鼠LD_(50)和肾脏氧化损伤的影响

为了探究8-羟基喹啉经口灌胃对小鼠的半数致死量(LD_(50))及小鼠肾脏氧化损伤的影响,首先采用改进寇氏法实验获得8-羟基喹啉的LD_(50),然后根据8-羟基喹啉的LD_(50)设定低、中、高3个剂量的实验组、溶剂对照组、空白对照组,连续给药7 d后取其肾脏,检测肾脏脏器系数,检测组织内丙二醛(MDA)、总超氧化物歧化酶(T-SOD)、谷胱甘肽过氧化物酶(GSH-Px)的含量和过氧化氢酶(CAT)活力.研究结果表明,8-羟基喹啉对小鼠的LD_(50)为139.96 mg·kg^(-1),95%置信区间131.9～148.5 mg·kg(-1),95%置信区间131.9～148.5 mg·kg^(-1);与对照组比较,溶剂组小鼠肾组织氧化损伤各指标无显著性差异;高浓度组,肾脏脏器系数值升高显著;8-羟基喹啉低、中、高3个剂量组的小鼠肾组织CAT活力下降,MDA含量增加均差异显著(P<0.05)且呈剂量—效应关系;高浓度组的小鼠肾组织T-SOD含量下降差异显著(P<0.05),各浓度组GSH-Px含量逐渐上升但无显著差异(P>0.05).实验浓度范围内8-羟基喹啉经口灌胃对小鼠肾组织具有氧化损伤作用.     

警惕儿童铅中毒

5岁的小胖是大班的幼儿,最近老师反映他上课坐不住,注意力不集中,有时还莫名其妙地说头痛。经检查发现,原来小胖的血铅水平高于正常值,属于中度铅中毒,他的一系列反常行为是铅中毒所引起的。铅是已知毒性最大、累积性极强的重金属之一,长期蓄积于人体,可严重危害人的神经、造血系统及消化系统,对小儿的智力和身体发育影响尤其严重。随看我国工业和交通业的迅速发展,铅污染对儿重健康的危害也正在加大。汽车尾气、家居涂料、文具、玩具等都会释放出含铅的气体,形成铅尘,因儿童的身高和发育快等因素,会比成年人吸入更多的铅。研究表明:儿童铅…     

复方金银花、茵陈五苓注射液对家兔内毒素性肾衰组织结构影响

目的:研究复方金银花和茵陈五苓两种注射液对内毒素所致家兔肾衰中肾脏组织结构的保护作用。方法:将重量2.5±0.25kg的健康雄性家兔32只,随机分为对照组、模型组、复方金银花组和茵陈五苓组,每组8只。模型组、复方金银花组、茵陈五苓组家兔一次性静脉注射大肠杆菌O111B4内毒素生理盐水,剂量为100ug/kg。两保护组家兔注射内毒素24h后静脉注射剂量为100ug/kg的中药注射液。模型组家兔静脉注射同容积的生理盐水。对照组家兔静脉注射与内毒素溶液和中药注射剂等体积的生理盐水。静脉注射内毒素及生理盐水后第7h处死。取肾组织标本,Bouns液固定,石蜡切片,HE染色,显微观察并摄影。结果:模型组肾脏肾小体血管球肿胀,有血栓形成,肾小囊壁层内皮细胞脱落,肾小囊腔变小,肾小管内皮细胞脱落。复方金银花组、茵陈五苓组肾脏的肾小体血管球略有肿胀,肾小囊的内皮细胞较完整,肾小囊腔较对照组稍变小。结论:复方金银花与茵陈五苓对家兔因内毒素所致肾衰中肾脏组织结构有确实的保护作用。     

健康频道

儿童血铅过高不必急着用药对一些健康状态不太好,或注意力不易集中的孩子,有时经血液化验会被诊断为血铅增高、铅中毒。目前“驱铅”、“排铅”治疗被过度宣传。但在不久前举行的2005年全国儿童铅中毒防治研讨会上,专家明确指出:“治疗儿童铅中毒的首选方法是营养干预和健康教育。”专家认为,儿童血铅水平高于或等     

感冒通对小白鼠的毒性研究

给不同年龄组小白鼠以不同剂量感冒通灌胃,小白鼠存活率下降,体重减轻,肝脏、肾脏的相对重量增加,胸腺相对重量减少。病理组织学观察结果表明:感冒通对小白鼠肝、肾等脏器有不同程度的损伤,且鼠龄愈小,用药剂量愈大,损伤愈重。     

铅和镉对小鼠骨髓细胞DNA损伤的检测

用灌胃法对小鼠进行染毒,设置染毒组剂量为1/32LD50、1/16LD50、1/8LD50、1/4LD50和1/2LD50,即Pb(NO3)2(3.75、7.5、15.0、30.0、60.0 mg/L)和Cd Cl2(5.84、11.69、23.38、46.75、93.50 mg/L),同时设蒸馏水为阴性对照。采用单细胞凝胶电泳法进行检测,试验结果用CASP彗星图像分析软件分析。结果表明:铅和镉均能引起小鼠骨髓细胞彗星细胞率的升高,染毒组的彗星细胞损伤各项指标均与对照存在显著差异,并呈现出一定的剂量-遗传毒理效应关系,表明重金属铅和镉可对小鼠骨髓细胞DNA造成一定程度的损伤,且镉的遗传毒性大于铅。     

The impact of complexity on the expertise reversal effect: experimental evidence from testing accounting students

Element interactivity is a central concept of cognitive load theory that defines the complexity of a learning task. The reduction of task complexity through a temporary segmentation or isolation of interacting elements was investigated with 104 students randomly assigned to an interacting elements group, where participants were required to deal with complex accounting problems in their entirety, or an isolated elements group, where the task was broken down into constituent components. The results provide strong support for the expertise reversal effect with isolated elements beneficial for novices, while interacting elements were appropriate for more knowledgeable learners. Critically, these results only were obtained for high rather than low element interactivity materials. It was concluded that segmentation or element isolation should consider the expertise of the learner in conjunction with the complexity of the learning material.     

土茯苓中药复方制剂与大蒜油对小鼠的排铅作用比较

目的：探讨土茯苓中药复方制剂和大蒜油的排铅效果,为铅中毒的防治提供一定的理论依据。方法：以40mg／L的醋酸铅溶液,按0．01mug体重剂量连续15d灌胃造模,造模成功后将48只雄性成年小鼠随机分成4组,即土茯苓中药复方制剂组、大蒜油组、乙二胺四乙酸组和中毒不治疗组,连续15d驱铅治疗。在造模前、第16天、第31天分别测定各组小鼠的体重及抽取小鼠尾部全血并用石墨炉原子吸收法直接测定小鼠的血铅含量,对实验结果进行统计学分析。结果：①血铅含量：统计学意义驱铅治疗后,土茯苓中药复方制剂组、大蒜油组、乙二胺四乙酸组分别与中毒不治疗组的血铅含量比较,差异均有统计学意义（P〈0．01）;土茯苓中药复方制剂组、大蒜油组、乙二胺四乙酸组的血铅含量两两比较,差异有统计学意义（P〈0．01）。驱铅治疗后各组的血铅含量为：土茯苓中药复方制剂组〈EDTA组〈大蒜油组〈中毒不治疗组。（参体重：土茯苓中药复方制剂组、大蒜油组分别与中毒不治疗组的体重比较,差异有统计学意义（P〈0．05）;土茯苓中药复方制剂组与大蒜油组的体重比较,差异有统计学意义（P〈0．05）。土茯苓中药复方制剂组的体重〉大蒜油组的体重。③存活率：土茯苓中药复方制剂组、大蒜油组分别与中毒不治疗组的存活率比较,差异有统计学意义（P〈0．01）;土茯苓中药复方制剂组与大蒜油组的存活率比较,差异无统计学意义（P〉O．05）。结论：土茯苓中药复方制剂、大蒜油对血铅均有促排作用;驱铅功效为：土茯苓中药复方制剂〉大蒜油。     

风力机叶片的有限元建模

以750kW中等长度水平轴风力机叶片为例,应用ANSYS软件,通过GUI操作界面实现复合材料风力机叶片的有限元建模。使实体模型可直接运用于力学性能分析,而无需再在CAD软件与有限元软件间相互转换。同时由于ANSYS软件对于复合材料分析的良好支持,使所建模型能更为真实的反映其结构性能,从而更好地为风力发电机的设计、分析服务。     

注射用丹参多酚酸对缺血性脑卒中患者的安全性评价

目的 观察注射用丹参多酚酸对缺血性脑卒中患者的生命体征和肝、肾功能变化状况,评价该药物在临床应用中的安全性.方法 将40例缺血性脑卒中患者根据其合并用药情况分为无合并用药组（A组,8例）、合并使用降压药组（B组,12例）和合并使用治疗脑梗死口服药物（C组,20例）3个组,对所有患者连续静脉滴注丹参多酚酸14天,在患者用药前和用药结束后3天内分别进行常规体格检查和肝、肾功能检测,并对结果进行分析.结果 40例患者3个组别,组内比较时,患者生命体征和肝肾功能指标用药前后的差异均无统计学意义（P＞0.05）.组间两两比较时,除了B组与C组患者用药后的舒张压、A组与B组患者用药后的肝功能ALT,差异具有统计学意义;其余组间比较,患者生命体征和肝肾功能指标用药前后,差异均无统计学意义（P＞0.05）.结论 注射用丹参多酚酸对缺血性脑卒中患者的生命体征和肝、肾功能影响甚小,该药物在临床应用中比较安全.     

Spatial and configural factors in compound stimulus processing by pigeons

Three matching-to-sample experiments examined whether spatial or configural factors determined how the element arrangement of compound sample stimuli influenced matching accuracy in pigeons. Seven types of compound stimuli were tested. The arrangement of color and line-orientation elements in these compounds varied in terms of the spatial separation between the elements, the degree of consistency in element spatial location, and the number of bounded areas containing the elements. Matching accuracy was examined upon initial exposure to the compounds, during asymptotic conditions of shared attention, and with variation of sample durations ranging from .04 to 5.935 sec. In all three experiments, when spatial proximity, locational certainty, and the number of lines were precisely controlled or equated, no evidence for the proposed configural processing of “unified” compounds was found (Lamb & Riley, 1981). Element spatial separation, and to a lesser degree perceptual limitations, determined compound performance. These results question our lab’s previous evidence for configural compound processing by pigeons (Lamb, 1988; Lamb & Riley, 1981). They suggest instead that pigeons independently and separately process the individual elements of color/line-orientation compounds, with element separation determining the distribution of processing between the elements.     

A comparison of individual and group contingency systems in a first-grade class

Individual and group management programs have been reported to be effective methods of reducing off-task behaviors; however, few studies have empirically contrasted the two intervention programs. Utilizing a multielement design, individual and group contingency systems were found to significantly reduce disruptive-unacceptable behaviors in a first-grade classroom, compared to baseline-reversal conditions. Teacher control statements also were significantly decreased within the treatment programs. No differences were found between the group and individual phases in reduction of student off-task behaviors or teacher control statements.     

生姜醇提物对糖尿病小鼠肾损害保护作用的研究

目的：探讨生姜醇提物对糖尿病小鼠肾损害的保护作用。方法：将30只KM种雄性小鼠随机分为三组,正常对照组（C组,n=10）、模型组（DM组,n=10）及生姜醇提物干预组（ZGB组,n=10）。DM组及ZGB组小鼠尾静脉注射2％四氧嘧啶（90mg／kg）建立糖尿病肾损害模型。造模成功后,ZGB组给予生姜醇提物溶液0．5mL（300mg／kg·d）灌胃14d,DM组及C组给予生理盐水灌胃。14d后小鼠断头取血,测定血糖、血清肌酐、尿素氮含量,检测肾组织丙二醛（MDA）及超氧化物歧化酶（SOD）活力的变化,光镜下观察肾组织病理学改变。结果：与DM组比较,ZGB组血糖、血肌酐及尿素氮水平明显低于DM组（P〈0．01）;肾组织MDA含量明显低于DM组（P〈0．01）,而T—SOD活力则较DM组升高（P〈0．01）。光镜下ZGB组肾脏组织形态学的异常改变较模型组减轻。结论：生姜醇提物对糖尿病小鼠的肾损害有一定的保护作用。     

使用有限元法预测针织结构复合材料热-弹性性能(英文)

预测纺织增强复合材料的热弹性性能是一项十分重要和复杂的课题 .本文采用有限元方法对玻璃纤维针织结构增强复合材料的正交各向异性热弹性性能进行了预测分析 ,并和试验结果进行了比较 .为了得到针织线圈增强结构的三维空间形态 ,本文考虑了相邻线圈之间的相互滑移作用和大位移变形 ,采用不考虑摩擦作用的接触单元建立线圈有限元模型 .     

模拟低氧训练对大鼠红细胞流变性的影响

目的:旨在观察2800m海拨高度的训练对大鼠血红蛋白及红细胞流变性的影响。方法:采用SD(Sprague-Dewley)大鼠40只,随机将其分为常氧常压组(LN),常氧常压训练组(LNT),低氧低压组(LH),低氧低压训练组(LHT)。LN、LNT组和LH、LHT分别置于正常海拔高度与相当于2800m的生活条件下,其训练环境同生活环境保持一致。LNT和LHT组分别在所控制的环境中,进行为期五周的训练。每周训练五天。结果:发现五周的低氧刺激或低氧训练,LH和LHT组的血红蛋白含量、红细胞压积和红细胞变形能力均显著升高(P<0.05),但LN和LNT组未发生显著变化。结论:五周的低氧刺激或低氧训练,均能提高大鼠机体内的血红蛋白含量、红细胞压积和红细胞变形能力,低氧刺激与低氧结合训练刺激所产生的效果并没有显著性差异。     

Study on the neurotoxic effects of low-level lead exposure in rats

Objective: To investigate effects of developmental lead exposure on nitric oxide synthase (NOS) activity in different brain regions and on N-methyl-D-aspartate (NMDA) receptor mRNA expression in the hippocampus of rats. On the basis of these observations, we explored possible mechanisms by which lead exposure leads to impaired learning and memorizing abilities in children. Methods: A series of rat animal models exposed to low levels of lead during the developing period was established (drinking water containing 0.025%, 0.05% and 0.075% lead acetate). NOS activities in the hippocampus, the cerebral cortex, the cerebellum and the brain stem were determined with fluorescence measurement and levels of mRNA expression of the NMDA receptor 2A (NR2A) subunit and NMDA receptor 2B (NR2B) subunit in the rat hippocampus were measured with Retro-translation (RT-PCR). Results: There were no differences in the body weight of rat pups between any of the groups at any given time (P>0.05). The blood lead level of Pb-exposed rat pups showed a systematic pattern of change: at 14 d of age, it was lower than that at 7 d of age, then rising to the peak level at 21 d and finally falling to lower levels at 28 d. The hippocampal NOS activities of lead-exposed groups were all lower than that of the control group on the 21st and 28th day (P<0.01). NOS activities in the cerebellum of lead-exposed groups were all lower than that of the control group on the 21st and 28th day (P<0.001) and the NOS activity of the 0.025% group was significantly lower than that of the 0.05% and 0.075% groups on the 28th day (P<0.05). NOS activity in the cerebral cortex of the 0.075% group was significantly lower than that of the control, 0.025% and 0.05% groups on the four day spans (P<0.001). There was no significant difference of NOS activity in the brain stem between any lead-exposed group and the control group on the four day spans. In the 0.05% and the 0.075% groups, the level of NR2A mRNA expression was higher than that in the control group at 7 d and 14 d of age (P<0.05). In the 0.025% group, the level of NR2A was found to be higher than that in the control group at 7 d of age only (P<0.05). No significant differences were found for the levels of NR2B mRNA expression between any of the groups at any given time. Conclusions: NOS activity in the hippocampus, the cerebral cortex and the cerebellum are inhibited by lead exposure. The degree of the inhibitory effect depends on the time span of exposure and the lead concentration. Developmental low-level lead exposure was found to raise the level of NR2A mRNA expression in the hippocampus of rats. Developmental low-level lead exposure does not affect the level of NR2B mRNA expression in the hippocampus.