氯吡脲连续灌胃给药4周对大鼠的毒性作用

为明确氯吡脲对大鼠的毒性作用,采用150、300和600 mg/kg剂量分别向SD大鼠灌胃 (ig) 给予氯吡脲,每日1次,连续给药4周。每日观察大鼠的中毒状况和死亡情况,每周记录体质量和摄食量;于停药后第1天和第15天分别处死SD大鼠,检测血常规、血清生化和凝血功能;取主要脏器进行称量,计算其脏器系数并进行常规病理组织学检查。结果发现:连续给药4周,氯吡脲对大鼠体质量、摄食量、血常规和凝血均无明显影响。停药后第1天,与溶剂对照组比较,氯吡脲300 mg/kg及以上剂量处理组雄性大鼠的尿素氮和肌酐含量明显升高 (P < 0.05),600 mg/kg剂量组血糖显著升高 (P < 0.05),其中,600 mg/kg处理组雄性大鼠的尿素氮、肌酐和血糖分别是对照的1.9、1.6和1.3倍。氯吡脲300 mg/kg及以上剂量组雌、雄性大鼠的肾脏系数均明显升高 (P < 0.05),其中300 mg/kg剂量组雌、雄性大鼠的肾脏系数分别是对照的1.2和1.1倍,600 mg/kg剂量组雌、雄性大鼠的肾脏系数分别是对照的1.4和1.1倍;300 和600 mg/kg剂量组雌性大鼠的肝脏系数明显升高 (P < 0.01),分别是对照的1.3和1.9倍。病理切片检查可见肾脏病理组织学改变,主要表现为轻度肾管萎缩,明显的白细胞管型、透明管型、间质炎性细胞浸润及肾小管扩张。停药后第15天,上述毒性反应症状有所恢复。研究表明,SD大鼠经连续灌胃给予氯吡脲4周,在600 mg/kg剂量下表现为明显肾脏毒性反应,在300 mg/kg剂量下表现为较轻微的肾脏毒性反应,推测氯吡脲的主要毒性靶器官可能是肾脏;其未见明显毒性反应剂量为150 mg/kg。     

Influence of Molecular Weight and Degree of Deacetylation of Low Molecular Weight Chitosan on the Bioactivity of Oral Insulin Preparations

The objective of the present study was to prepare and characterize low molecular weight chitosan (LMWC) with different molecular weight and degrees of deacetylation (DDA) and to optimize their use in oral insulin nano delivery systems. Water in oil nanosized systems containing LMWC-insulin polyelectrolyte complexes were constructed and their ability to reduce blood glucose was assessed in vivo on diabetic rats. Upon acid depolymerization and testing by viscosity method, three molecular weights of LMWC namely, 1.3, 13 and 18 kDa were obtained. As for the DDA, three LMWCs of 55%, 80% and 100% DDA were prepared and characterized by spectroscopic methods for each molecular weight. The obtained LMWCs showed different morphological and in silico patterns. Following complexation of LMWCs with insulin, different aggregation sizes were obtained. Moreover, the in vivo tested formulations showed different activities of blood glucose reduction. The highest glucose reduction was achieved with 1.3 kDa LMWC of 55% DDA. The current study emphasizes the importance of optimizing the molecular weight along with the DDA of the incorporated LMWC in oral insulin delivery preparations in order to ensure the highest performance of such delivery systems.     

Vaccination strategies with oral booster for surubim hybrid (Pseudoplatystoma corruscans × P. reticulatum) against haemorrhagic septicaemia

This study evaluated the efficiency of differently prepared vaccines against Aeromonas hydrophila in the hybrid surubim (Pseudoplatystoma corruscans × P. reticulatum). Survival and haemato‐immunological parameters were compared between the treatments: non‐vaccinated fish (C); bacterin‐vaccinated fish (B); bacterin plus oral booster vaccinated fish (B+O); bacterin and toxoid‐vaccinated fish (B+T) and bacterin, toxoid and oral booster‐vaccinated fish (B+T+O). Fourteen‐days vaccinated fish from B+O and B+T+O were fed with an oral booster for 4 days. After 1 week, the fish were intraperitoneally challenged with 2 × 10⁸ CFU mL^?1 of A. hydrophila. Fish from the treatment B+T+O showed the lowest cumulative mortality (11.36%) 96 h after challenge, compared with other treatments (22.72–44.04%), and a relative survival of 74%. Serum immunoglobulin in B+T+O fish was higher than in other treatments. All vaccinated fish showed an increased agglutination titre when compared with non‐vaccinated fish, both before and after challenge. Fish fed with oral booster showed an increase in phagocytic percentage before and after challenge. It can be inferred that the oral booster vaccination was efficient in reducing mortality in hybrid surubim by enhancing the response against haemorrhagic septicaemia due to A. hydrophila infection.     

Correlation between oral fluid and plasma oxytetracycline concentrations after intramuscular administration in pigs

The penetration of oxytetracycline (OTC) into the oral fluid and plasma of pigs and correlation between oral fluid and plasma were evaluated after a single intramuscular (i.m.) dose of 20 mg/kg body weight of long‐acting formulation. The OTC was detectable both in oral fluid and plasma from 1 hr up to 21 day after drug administration. The maximum concentrations (C_max) of drug with values of 4021 ± 836 ng/ml in oral fluid and 4447 ± 735 ng/ml in plasma were reached (T_max) at 2 and 1 hr after drug administration respectively. The area under concentration–time curve (AUC), mean residence time (MRT) and the elimination half‐life (t_1/2β) were, respectively, 75613 ng × hr/ml, 62.8 hr and 117 hr in oral fluid and 115314 ng × hr/ml, 31.4 hr and 59.2 hr in plasma. The OTC concentrations were remained higher in plasma for 48 hr. After this time, OTC reached greater level in oral fluid. The strong correlation (r = .92) between oral fluid and plasma OTC concentrations was observed. Concentrations of OTC were within the therapeutic levels for most sensitive micro‐organism in pigs (above MIC values) for 48 hr after drug administration, both in the plasma and in oral fluid.     

不同水温联合用药中恩诺沙星在鲤体内的药代动力学及残留的影响

为比较水温对没食子酸与恩诺沙星联合用药后恩诺沙星在福瑞鲤体内的药代动力学及其残留消除规律的影响,采用对照试验,将福瑞鲤随机分为高温组(26±1)℃和低温组(20±1)℃,没食子酸与恩诺沙星按质量比10∶1配伍后单次混饲口灌给药,用量为体质量2 mg/kg(以恩诺沙星计),血浆、肌肉、肝胰脏、肾脏各组织样品中的恩诺沙星含量经高效液相色谱法测定。数据经DAS 3.0药物代谢动力学软件的非房室模型统计矩方法分析。结果表明:恩诺沙星在血浆中高温组达峰时间T_(max)(0.75 h)早于低温组(4 h),且高温组达峰浓度C_(max)、药时曲线下面积AUC、表观分布容积Vz均大于低温组,分别为1.966 mg/L、130.122 mg/(L·h)、16.9 L/kg和1.610 mg/L、102.795 mg/(L·h)、3.186 L/kg。在鱼体肌肉、肝胰脏、肾脏中的药物浓度均呈现先升高后降低的变化趋势。高温组各组织中的药物在达峰前均高于低温组相应组织含量,而达峰后,高温组较低温组消除更快。表明水温对与没食子酸联用后恩诺沙星的吸收、分布、消除代谢均有较大促进作用。     

网络广告的博弈与监管

网络广告已逐渐成为消费者了解商品价格、特性与种类的重要信息来源,其宣传的力度影响着消费者的选择;但过分依赖网络广告不仅可能将企业自己带入绝境,还会侵害到消费者的利益。从博弈的角度分析企业网络广告和市场占有率之间的关系,陷入网络广告恶战的原因,并对网络广告监管提出一些建议。     

促进高校机关党建科学发展的若干思考

高校机关党组织是高校党组织的重要组成部分,本文从坚持用中国特色社会主义理论体系武装机关党员、干部的头脑,坚持用科学发展观指导机关党组织建设,紧紧围绕高校的中心工作加强机关党组织建设以及建立科学评估体系提升机关党建工作水平等方面,提出了切实加强和改进高校机关党组织建设的思路。     

Web2．0下图书馆隐性知识的组织探讨

隐性知识管理一直是图书馆管理的难点,而Web2．0的出现为隐性知识管理提供了一种新的方式。通过对Web2．0技术在图书馆隐性知识管理的应用现状的分析,探讨了Web2．0环境下图书馆隐性知识管理存在的障碍,并在此基础上提出了相应的策略。     

光合细菌中试生产质量管理体系的建立

对光合细菌(PSB)培养的最适温度、光照、pH等条件及培养基优化进行了系统研究。结果表明,PSB生长的最适条件为:温度30℃,光照强度5 000 lx,pH 8.0。同时提出从菌种质量标准、环境控制、生产过程质量监控以及产品质量标准等方面建立光合细菌中试生产过程中的质量管理体系。