过氧化氢对小鼠骨髓微核率和孕鼠胚胎着床及生长的影响

通过体内试验研究了过氧化氢对小鼠骨髓微核率和胚胎着床及孕鼠生长发育的影响。将妊娠的昆明种(KM)小鼠分成5个处理组,分别为环磷酰胺(40.00 mg/kg)、蒸馏水和过氧化氢(500.00,125.00,31.25 mg/kg)组。于妊娠后6~15 d,每天采用灌胃给药,环磷酰胺组于妊娠后11~13 d腹腔一次性注射。每3 d称重1次,于妊娠第18 d称重后剖腹检查。另取雌雄各半KM小鼠分成5个处理组,分别为环磷酰胺、蒸馏水和过氧化氢(500.00,100.00,10.00 mg/kg)组,均采用灌胃染毒,每天1次,连续4 d,第5 d处死小鼠,取股骨髓液常规制片,计算红细胞微核率。结果表明,吸收胎和死胎数蒸馏水组为5.56%,中剂量过氧化氢组增加到19.53%(P<0.01),低剂量组增加到13.14%(P<0.05)。蒸馏水组小鼠嗜多染红细胞微核率为0%~0.002%,过氧化氢组增加到0.017%~0.032%(P<0.01)。在本试验剂量范围内过氧化氢有明显的胚胎毒性和遗传毒性。     

紫锥菊根末的安全药理学研究

对健康昆明小鼠连续一周灌服不同浓度的紫锥菊根末生药液,观察其对健康昆明小鼠中枢神经系统、呼吸系统和心率的影响,以考察紫锥菊根末的潜在不良反应.结果表明,紫锥菊根末对健康昆明小鼠的中枢神经系统、呼吸系统和心率均无明显影响.     

实验小鼠肠道鞭毛虫研究Ⅰ昆明神小鼠肠道鞭毛虫区系分布、自然感染状况

作者对７０只开放系统内饲养的不同年龄、性别昆明种小鼠作了肠道鞭毛虫区系分布、自然感染状况的观察，共检出８种肠道鞭毛虫．其感染率和肠道分布如下：鼠唇鞭毛虫感染率为８０．００％，多见于盲肠、小肠后端；鼠贾第虫感染率为５１．４３％，多见于小肠前端；鼠六鞭毛虫为６８．５７％，多见于小肠前端；鼠八鞭毛虫为７８．５７％，多见于盲肠；人五毛滴虫为８８．５７％，多见于盲肠、结肠；田鼠四毛滴虫为８２．８６％，多见于盲肠；微小三毛滴虫为４７．１４％，多见于盲肠、结肠；鼠三毛滴虫为９１．４３％，多见于盲肠、结肠及小肠后端。被检７０只小鼠均有肠道鞭毛虫感染，其中感染７种肠道鞭毛虫的有９只，占被检总数的１２．８６％，８种全部感染的有６１只，占被检总数的８７．１４％．     

白消安注射法建立昆明小鼠精原干细胞移植受体模型

【目的】通过对6周龄昆明小鼠腹腔内单次注射不同剂量的白消安来制作精原干细胞移植受体模型。【方法】将104只昆明小鼠随机分成4组,分别注射0(对照组,注射等量的白消安溶解液二甲基亚砜(DMSO)),10,20和30mg/kg白消安,于注射白消安后5,7,9,11和13周记录小鼠的死亡数、小鼠睾丸外观体积、小鼠睾丸质量和小鼠体质量,计算睾丸指数;通过组织学观察注射不同剂量白消安后小鼠曲细精管精子的恢复情况,并检测受体小鼠血液中红细胞和白细胞数量的变化。【结果】注射0(对照组),10,20和30mg/kg白消安13周后,小鼠死亡率分别为0(0/22),11.54%(3/26),17.86%(5/28)和89.29%(25/28)。10mg/kg白消安组小鼠的睾丸指数在注射后5,7和9周显著小于对照组(P0.05),而在注射后11和13周,与对照组差异不显著(P0.05);在注射后不同时间,对照组和10mg/kg白消安组的睾丸指数均显著高于20mg/kg白消安组(P0.05)。在注射白消安5,7,9,11和13周后,对照组曲细精管上皮无变化;10和20mg/kg白消安组有完整精子发生的曲细精管占总曲细精管的百分比分别为(49.56±8.23)%,(66.61±6.13)%,(80.24±10.42)%,(93.87±3.23)%,(92.49±4.58)%;(8.73±9.22)%,(9.89±6.39)%,(29.21±12.31)%,(49.64±3.59)%和(81.99±4.98)%。受体小鼠红细胞和白细胞数量均随着处理时间及白消安处理剂量的变化而变化。【结论】腹腔内注射20mg/kg白消安小鼠的死亡率、睾丸指数均较低,中空的曲细精管数量多,且恢复较慢,适于做精原干细胞移植的受体,合适的移植时间是白消安处理后5~7周。     

吗啡对不同来源KM小鼠的镇痛、耐受和身体依赖性的比较

用吗啡对A、B、C3家实验动物繁育生产专业单位KM小鼠进行镇痛、耐受性和身体依赖性的比较实验。结果显示,A、B、C3家单位KM小鼠的利用率分别为70%、77%和81%,吗啡热板法镇痛ED50分别为3.611mg/kg、3.635mg/kg和5.096mg/kg,A单位KM小鼠吗啡镇痛起效最快,作用维持时间最长,C单位KM小鼠镇痛作用最弱。吗啡的耐受性实验结果表明,3家单位的KM小鼠之间没有差异,但是吗啡的身体依赖性实验结果表明,B、C单位KM小鼠与A单位小鼠之间有显著性差异(p<0.01)。结果提示,用吗啡对KM小鼠进行镇痛实验时,必须使用同一来源的动物,此外,加速我国KM小鼠的标准化研究迫在眉睫。     

数字内容产业知识管理探析

基于数字内容产业提供的产品是知识产品、数字内容组织的管理主要是对知识的管理。文章创造性地提出运用知识管理的思想和工具来管理和改进数字内容产业。从商业信息网站的知识管理探讨开始，深入分析了知识管理在数字内容产品生产中的应用，并就如何建设适应知识管理的基础环境提出四点建议。     

清洁级KM小鼠血清中5种微量元素的测定

在SPF屏障系统内,按一般方法饲养清洁级KM小鼠,采用原子吸收光谱法测定血清中5种微量元素含量,进行统计学分析。结果表明,KM小鼠血清中5种微量元素的含量顺序大小是Ca>Mg>Fe>Zn>Cu。雌雄KM小鼠之间血清中微量元素Zn、Fe、Mg含量比较,差异具有显著性(P<0.05)。     

不同日龄昆明小鼠外部形态数量性状与肥满度的关系

随机抽取我国不同地区6个群体28、56和112日龄的昆明小鼠,称其体重,并对其全长、头长、体长和尾长进行测量,计算肥满度。发现KM小鼠外部形态数量性状随生长发育时间延长而增加(P<0.05),其中28和56日龄增长最快。头长和体重在性别上的差异出现较早(28日龄),而体长和尾长出现较晚(112日龄)。逐步回归分析发现,年龄和体长对肥满度皆呈负性作用,全长和体重呈正性作用;对肥满度协同作用最大的数量性状雌性为头长和体重,雄性为体重和体长。提示在优化我国昆明小鼠时可因性别差异选择不同的外部形态数量性状参数。     

Kinetics of nitric oxide consumption in tropical soils under oxic and anoxic conditions

The kinetics of nitric oxide consumption in four tropical soils were studied under oxic and anoxic conditions in a flow-through system in the laboratory. Under anoxic conditions the soils had a very high affinity for NO, resulting in K _M values of 0.02–0.27 ppmv NO (equivalent to 0.04–0.50 nM NO in the aqueous phase). These K _M values were lower than literature values for NO consumption by denitrifying bacteria. Under oxic conditions the kinetics of NO consumption in the tropical soils were completely different, exhibiting K _M values higher than 1.7 ppmv. These higher K _M values were similar to literature values for NO consumption by aerobic heterotrophic bacteria. Thus, the tropical soils studied seem to contain two different NO consumption activities which can be distinguished by their kinetics and which predominate under aerobic and anaerobic conditions, respectively. However, it was not possible to quantify the contribution of each process to total NO consumption under natural conditions. Under aerobic conditions NO turnover kinetics were positively correlated with soil respiration, N mineralisation and soil organic carbon, whereas under anaerobic conditions they were positively correlated with potential and actual denitrification rates and pH. Received: 26 September 1996     

Effect of winter cover crop species and planting methods on maize yield and N availability under irrigated Mediterranean conditions

Under semiarid Mediterranean conditions irrigated maize has been associated to diffuse nitrate pollution of surface and groundwater. Cover crops grown during winter combined with reduced N fertilization to maize could reduce N leaching risks while maintaining maize productivity. A field experiment was conducted testing two different cover crop planting methods (direct seeding versus seeding after conventional tillage operations) and four different cover crops species (barley, oilseed rape, winter rape, and common vetch), and a control (bare soil). The experiment started in November 2006 after a maize crop fertilized with 300 kg N ha⁻¹ and included two complete cover crop-maize rotations. Maize was fertilized with 300 kg N ha⁻¹ at the control treatment, and this amount was reduced to 250 kg N ha⁻¹ in maize after a cover crop. Direct seeding of the cover crops allowed earlier planting dates than seeding after conventional tillage, producing greater cover crop biomass and N uptake of all species in the first year. In the following year, direct seeding did not increase cover crop biomass due to a poorer plant establishment. Barley produced more biomass than the other species but its N concentration was much lower than in the other cover crops, resulting in higher C:N ratio (>26). Cover crops reduced the N leaching risks as soil N content in spring and at maize harvest was reduced compared to the control treatment. Maize yield was reduced by 4 Mg ha⁻¹ after barley in 2007 and by 1 Mg ha⁻¹ after barley and oilseed rape in 2008. The maize yield reduction was due to an N deficiency caused by insufficient N mineralization from the cover crops due to a high C:N ratio (barley) or low biomass N content (oilseed rape) and/or lack of synchronization with maize N uptake. Indirect chlorophyll measurements in maize leaves were useful to detect N deficiency in maize after cover crops. The use of vetch, winter rape and oilseed rape cover crops combined with a reduced N fertilization to maize was efficient for reducing N leaching risks while maintaining maize productivity. However, the reduction of maize yield after barley makes difficult its use as cover crop.