眼镜蛇神经毒素的急性毒性实验研究

目的　研究眼镜蛇神经毒素 （ Ｃｏｂｒａ ｎｅｕｒｏｔｏｘｉｎ, Ｎ Ｔ） 的急性毒性和蓄积毒性。方法　测 Ｎ Ｔ 对小鼠的 Ｌ Ｄ５０ ; 对大鼠、狗的１ 次性最小中毒剂量和最大安全剂量; 计算 Ｎ Ｔ 在小鼠、狗体内的２４ｈ 蓄积率。结果　 Ｎ Ｔ 经静注、肌注、腹腔、皮下 ４ 种途径给药对小鼠的 Ｌ Ｄ５０ 分别是 （１９５±９５） μｇ／ｋｇ、（１５６±８５） μｇ／ｋｇ、（１５１±１９） μｇ／ｋｇ、（１８４±８５） μｇ／ｋｇ, 对小鼠的最小致死剂量为９７５μｇ／ｋｇ。 Ｎ Ｔ 对大鼠、狗的１ 次性中毒剂量分别为５４μｇ／ｋｇ 和３４μｇ／ｋｇ。对小鼠、大鼠和狗的安全剂量分别为８１５μｇ／ｋｇ、４２μｇ／ｋｇ和３０μｇ／ｋｇ, 分别约为人临床用剂量 （７０μｇ／５０ｋｇ·ｄ－ １ ） 的５８２、３０ 和２１ 倍。 Ｎ Ｔ 在小鼠、狗体内的２４ｈ蓄积率分别为 ５７％ 和３０％ 以上。结论　 Ｎ Ｔ 在使动物中毒的剂量下有广泛的安全范围; Ｎ Ｔ 在动物体内存在弱蓄积毒性。     

益寿汤对小鼠免疫和抗应激能力的影响

给小鼠益寿汤１ｇ／ｋｇ,２ｇ／ｋｇ,４ｇ／ｋｇ灌胃连续７ｄ,分别检测其抗应激能力和免疫功能的变化。结果表明：益寿汤４ｇ／ｋｇ组小鼠较对照组负重游泳耗竭时间和常压耐缺氧生存时间明显延长,益寿汤２ｇ／ｋｇ和４ｇ／ｋｇ可提高小鼠耐寒能力,各剂量益寿汤均可显著提高小鼠血清溶血素及碳粒廓清吞噬数,但对迟发型变态反应无明显影响。     

重组人IL6／2融合蛋白对6.5Gy照射小鼠造血功能恢复的影响

观察了ｈＦＰＩＬ６／２对６．５Ｇｙγ线照射ＮＩＨ小鼠第１０天造血功能恢复的影响。结果表明：照射小鼠连续４ｄ给予ｈＦＰＩＬ６／２２５０μｇ·ｋｇ－１·ｄ－１,其脾重、ＣＦＵ－８、骨髓有核细胞数及ＣＭ－ＣＦＵ分别比对照组增加５９．０％、２７８．５％、５７．９％和１３８．２％,统计学处理均有显著差异;对此四项指标的改善也明显优于２５μｇ组。另外,２５０μｇ剂量组小鼠外周血象３０ｄ的动态观察结果表明,ｈＦＰＩＬ６／２不但能明显提高红细胞和血红蛋白的最低值,而且能使血小板的恢复提前。提示ｈＦＰＩＬ６／２在促进血小板生成和促进红系造血方面可能具有良好的应用前景。     

顺天胶囊对高脂模型大鼠血脂,血粘度和血小板凝集的影响

本文探讨了顺天胶囊对高脂模型大鼠血脂、血粘度和血小板凝集的影响。实验结果表明,顺天胶囊在0.5、1、28/ks·d连续灌胃给药30d时,能分别降低大鼠甘油三脂水平和全血粘度;1s/kg和2g/kg两组血清高密度脂蛋白含量明显升高(P<0.01),血小板聚集明显抑制,但低剂量组(0.5g/kg)对各项指标影响不明显。     

猕猴注射黄曲霉素B和乙型肝炎病毒后丝裂霉素诱发SCE的研究

丝裂霉素C(MMC)是一种抗癌的双功能烷化剂,能诱发染色体畸变和使姐妹染色单体互换率显著增高,本实验以弥猴为实验材料,探讨强烈致癌因子黄曲霉素D(AFB_1),乙型肝炎病毒(HBV)和MMC在诱发SCE时的相互关系。 四只2—3年龄的猕猴(Macaca mulatta),一只雄性猕猴按公斤体重100微克剂量肌肉注射AFB_1(溶剂为二甲亚砜),另一只雄性猕猴静脉注射乙型肝炎患者血清0.2毫升。半个月后再次静脉注射患者的全血0.5毫升。一只雌性猕猴在注射AFB_1后再按上法注射乙型肝炎患者的血清和全血。另一只雄性猕猴为对照。最后一次注射的次日,抽取静脉     

胸腺肽α_1活性片段和其自旋标记衍生物的合成及免疫活性研究

报道了胸腺肽α_１活性片段Ｔｈｙｍｏｓｉｎα_１［Ｌｙｓ（２３）］（２３－２７）ＯＨ和其自旋标记衍生物的合成及对实验动物免疫功能的影响。其氨基酸序列分别为Ｈ_２Ｎ－Ｌｙｓ－Ｇｌｕ－Ｇｌｕ－Ａｌａ－Ｇｌｕ－ＯＨ,用Ｔｈｙα_１［Ｌｙｓ~（２３）］表示,修饰物为Ｇｌｕ－ＯＨ）,用Ｔｈｙα_１［Ｌｙｓ~（２３）］·Ｒ表示。ＨＰＬＣ测得该肽的纯度在９０％以上,ＥＳＲ谱测定自旋标记衍生物给出氮氧自由基信号,氨基酸组成与预期值相符。实验小鼠腹腔连续注射剂量为０．１、１、１０、１００和１０００μｇ／ｋｇ的该肽１０天后,发现腹腔巨噬细胞吞噬功能、ＥＲＦＣ阳性率及血清溶血素含量明显升高,且最佳剂量在０．１－１０μｇ／ｋｇ范围。实验结果表明人工合成胸腺肽α_１活性片段及其自旋标记衍生物具有显著的免疫促进活性。     

香菇多糖对小鼠免疫功能调节的影响

香菇多糖是从香菇的菌丝体提取的高分子葡聚糖 ,除具有抑制肿瘤生长、转移作用外 ,能影响机体多种免疫功能 ,使Ｔ细胞恢复活性 ,促进白细胞介素的产生 ,还能促进单核巨噬细胞的功能 ,临床上已作为免疫增强剂 ,用于肿瘤和慢性肝炎的辅助治疗[1] 。1　材料与方法1.1　材料　　实验动物分组及处理　小鼠随机分成 5组。第1组为对照组 ;第 2组注射生理盐水 ;第 3组注射香菇多糖 1ｍｇ/ｋｇ ;第 4组注射香菇多糖 5ｍｇ/ｋｇ ;第5组注射香菇多糖 10ｍｇ/ｋｇ。均作皮下注射 ,连续注射 5ｄ ,停药品 1ｄ ,第 7ｄ拉颈处死。1.2　方法1.2 .1　ＬＡＫ细…     

沈阳地区运动员冬训后全血微量元素含量与肺通气功能相关性研究

微量元素Ｚｎ、Ｃｕ、Ｆｅ及常量元素Ｃａ、Ｍｇ在应激状态时的代谢具有重要作用。Ｃｕ在维持机体内环境的稳定、电子传递以及氧化磷酸化过程有重要的功能。Ｚｎ可涉及多种酶的活性。冬训后肺通气功能的加强 ,会导致Ｈｂ携带Ｏ2 ,ＣＯ2 能力增加 ,同时有全血微量元素的改变 ,但肺通气功能的改善与全血微量元素之间的关系尚未见报道。本文旨在探讨冬训后运动员全血微量元素的变化及其与肺通气功能主要指标的相关性1　材料与方法(1)实验对象　①沈阳市体育运动学校 42人 ,男性 ,年龄 14～ 19岁 (Ａ组 )。②沈阳医学院 44人 ,男性 17～ 2 3岁 (…     

野生猕猴应激与抗应激的研究

本文以野生猕猴为实验对象 ,以血清皮质醇含量为指标 ,研究了野生猕猴被捕获与给予氯丙嗪、Vc 等药物后上述指标的变化。结果表明 :(1)野生猕猴在被捕获后的 1～ 2周内 ,血清皮质醇一直维持在一个高水平状态 (2 4 78± 0 2 0 μg/dl,2 4 88± 0 5 8μg/dl) ;(2 )氯丙嗪可使动物行为处于一种安静状态 ,但并不降低血清皮质醇水平 (2 8 73± 6 16 μg/dl) ,(3)Vc 可改善动物的精神状态 ,使血清皮质醇略低 (2 1 0 0± 2 90 μg/dl) (P >0 0 5 ) ,(4)氯丙嗪和Vc 合用后 ,血清皮质醇与单独使用氯丙嗪无明显差异 (2 8 0 7± 4 45 μg/dl)。     

人工饲养中国猕猴中SRV、STLV和BV的流行病学调查

非人灵长类动物是十分重要的生物医学资源。由于与人类在生理生化、免疫、遗传等方面近似,猕猴是重要的非人灵长类实验动物之一。然而,猕猴作为自然宿主,易感染D型逆转录病毒(simian type D retrovirus,SRV)和T淋巴细胞白血病病毒(simian T lymphotropic virus,STLV)这两种逆转录病毒,并可能会影响AIDS猕猴动物模型等的研究结果。猴B病毒(ceropithecine herpesvirus1,BV)对猕猴及动物从业人员均有危害。云南省拥有较大规模的中国猕猴繁殖种群。基于以上原因,建立SPF级别的中国猕猴种群十分必要。该文应用PCR技术筛查了人工饲养种群中411只中国猕猴的SRV、STLV和BV感染流行情况。结果表明:SRV、STLV和BV的阳性感染率分别为19.71%(81/411)、13.38%(55/411)和23.11%(95/411)。同时比较分析了不同性别及年龄组中国猕猴的病毒感染情况。该研究将有助于建立SPF级别的中国猕猴繁殖种群。     

壳聚糖酶的克隆表达与壳寡糖的制备分析

目的:克隆壳聚糖酶基因于大肠杆菌中实现高表达,制备壳寡糖。方法:以枯草芽孢杆菌总DNA为模板扩增壳聚糖酶基因(CSN),克隆至载体pET23a(+)上,转化菌株BL21(DE3)。重组子经0.5 mmol/L IPTG诱导后,SDS-PAGE和质谱检测与鉴定重组酶。酶纯化后水解壳聚糖,薄层色谱分析其水解产物。结果:质谱证明壳聚糖酶(31.5kDa)成功表达,表达量占菌体总蛋白的45%左右。纯化后重组酶浓度为900 mg/L,纯度95%、回收率85%,酶活力为10 000 U/mg。壳聚糖降解产物为壳二糖至壳四糖。结论:原核表达载体pET23a(+)-CSN构建正确,壳聚糖酶表达量与活性高,适用于水解壳聚糖制备壳寡糖。     

国内外蝗害治理技术现状与展望

本文首先概述了国内外蝗虫发生与为害的态势,总结了现阶段我国蝗虫发生与为害的主要特点:即农田飞蝗暴发频繁而且严重,草原土蝗的发生时常造成严重的经济损失,而且侵入城市干扰市民生活,我国与周边国家之间蝗虫过境迁移频繁,使用化学农药污染环境和农产品;分析了国内外蝗虫防治对策与技术的发展现状,重点介绍了应急防治和可持续治理对策、...     

Synthesis and turnover of cerebrosides and phosphatidylserine of myelin and microsomal fractions of adult and developing rat brain.

The synthesis and turnover of cerebrosides and phospholipids was followed in microsomal and myelin fractions of developing and adult rat brains after an intracerebral injection of [U-14C]serine. The kinetics of incorporation of radioactivity into microsomal and myelin cerebrosides indicate the possibility of a precursor-product relationship between cerebrosides of these membranes. The specific radioactivity of myelin cerebrosides was corrected for the deposition of newly formed cerebrosides in myelin. Multiphasic curves were obtained for the decline in specific radioactivity of myelin and microsomal cerebrosides, suggesting different cerebroside pools in these membranes. The half-life of the fast turning-over pool of cerebrosides of myelin was 7 and 22 days for the developing and adult rat brain respectively. The half-life of the slowly turning-over pool of myelin cerebrosides was about 145 days for both groups of animals. The half-life of the rapidly turning-over microsomal cerebrosides was calculated to be 20 and 40 h for the developing and adult animals respectively. The half-life of the intermediate and slowly turning-over microsomal cerebrosides was 11 and 60 days respectively, for both groups of animals. The amount of incorporation of radioactivity into microsomal cerebrosides from L-serine was greatly decreased in the adult animals, and greater amounts of the precursor were directed towards the synthesis of phosphatidylserine. In the developing animals, considerable amounts of cerebrosides were synthesized from L-serine, besides phosphatidylserine. The time-course of incorporation indicated that a precursor-product relationship exists between microsomal and myelin phosphatidylserine. The half-life of microsomal phosphatidylserine was calculated to be about 8 h for the fast turning-over pool in both groups of animals.     

Identification and composition of the tonsillar and anal enterococcal and streptococcal flora of dogs and cats

Enterococcus faecalis was the most frequently isolated enterococcal species from anal swabs and tonsils of dogs and cats, although in the anal samples from dogs Ent. hirae was found almost as often as Ent. faecalis. Most Ent.faecium strains from dog tonsils differed from those associated with humans and other animals in that they fermented sorbitol. Typical Ent. avium as well as atypical Ent. avium -like strains were seen in dogs, while the related species Ent. raffinosus was associated with cat tonsils. Enterococcus cecorum also occurred mainly in cats. Certain atypical strains, presumptively identified as Ent. cecorum , shared characteristics with Ent. columbae.
The most frequent streptococcal species in tonsils of cats and dogs were Streptococcus suis and Strep. canis. Streptococcus canis and Strep. bovis predominated in anal swabs. The canine Strep. suis differed from the common porcine strains in fermenting mannitol.
Forty-seven of the 288 isolates examined could not be identified or related to known species. The characteristics of two groups of these bacteria, provisionally called 'Ton 31 group' and 'O7 group' are described.     

Molecular characterisation of species and genotypes of Cryptosporidium and Giardia and assessment of zoonotic transmission

The molecular characterisation of species and genotypes of Cryptosporidium and Giardia is essential for accurately identifying organisms and assessing zoonotic transmission. Results of recent molecular epidemiological studies strongly suggest that zoonotic transmission plays an important role in cryptosporidiosis epidemiology. In such cases the most prevalent zoonotic species is Cryptosporidium parvum. Genotyping and subtyping data suggest that zoonotic transmission is not as prevalent in the epidemiology of giardiasis. Molecular characterisation of Cryptosporidium and Giardia is a relatively recent application that is evolving as new genes are found that increase the accuracy of identification while discovering a greater diversity of species and yet unnamed taxa within these two important genera. As molecular data accumulate, our understanding of the role of zoonotic transmission in epidemiology and clinical manifestations is becoming clearer.     

白术同源四倍体的诱导和鉴定及其与二倍体过氧化物酶的比较

以白术（Atractylodes macrooephala Koidz.）二倍体组培苗为材料,对其四倍体诱导方法进行研究,共获得45个白术同源四倍体株系,为优良株系的选育提供了材料。此外,还分析比较了其中8个白术四倍体株系与二倍体的过氧化物酶同工酶（POD）的酶谱差异,发现四倍体各株系过氧化物酶同工酶谱比二倍体的均多了Rf0.310的谱带,且总过氧化物酶比活力也发生了很大改变,对探讨白术四倍体优良株系的生理生化机理具有一定的参考价值。     

Kinetics and thermodynamics of peroxidase- and laccase-catalyzed oxidation of N-substituted phenothiazines and phenoxazines

N -substituted phenothiazines (PTs) and phenoxazines (POs) catalyzed by fungal Coprinus cinereus peroxidase and Polyporus pinsitus laccase were investigated at pH 4–10. In the case of peroxidase, an apparent bimolecular rate constant (expressed as k _cat/K _m) varied from 1 ×10⁷M⁻¹s⁻¹to 2.6×10⁸M⁻¹s⁻¹ at pH 7.0. The constants for PO oxidation were higher in comparison to PT. pH dependence revealed two or three ionizable groups with pK _a values of 4.9–5.7 and 7.7–9.7 that significantly affected the activity of peroxidase. Single-turnover experiments showed that the limiting step of PT oxidation was reduction of compound II and second-order rate constants were obtained which were consistent with the constants at steady-state conditions. Laccase-catalyzed PT and PO oxidation rates were lower; apparent bimolecular rate constants varied from 1.8×10⁵M⁻¹s⁻¹ to 2.0×10⁷M⁻¹s⁻¹ at pH 5.3. PO constants were higher in comparison to PT, as was the case with peroxidase. The dependence of the apparent bimolecular constants of compound II or copper type 1 reduction, in the case of peroxidase or laccase, respectively, was analyzed in the framework of the Marcus outer-sphere electron-transfer theory. Peroxidase-catalyzed reactions with PT, as well as PO, fitted the same hyperbolic dependence with a maximal oxidation rate of 1.6×10⁸M⁻¹s⁻¹ and a reorganization energy of 0.30 eV. The respective parameters for laccase were 5.0×10⁷M⁻¹s⁻¹ and 0.29 eV. Received: 20 September 1999 / Accepted: 24 February 2000