Enhancement effect of adenovirus mediated antisense c-myc gene and caffeine on chemotherapy of osteosarcoma cells to cisplatin

AIM: The cancer biology has showed that overexpression of oncogenes is responsible for the progression of human malignancies,antisense technology can block a certain gene expression.Caffeine has enhancement effect on chemotherapy of osteosarcoma cells to cisplatin,we constructed the recombinant adenovirus (Ad-Asc-myc) encoding antisense c-myc fragment and investigated its effect on the in vitro sensitivity of osteosarcoma MG-63 cells to cisplatin.METHODS: The recombinant adenovirus (Ad-Asc-myc) encoding antisense c-myc fragment was constructed by cloning c-myc cDNA of about 750 base pairs in a reverse direction into adenovirus vector.Ad-Asc-myc and caffeine was used respectively or together to co-operate with cisplatin to treat the osteosarcoma MG-63 cells in vitro,and Western blotting,MTT,flow cytometry (FCM),electron microscope were used to evaluate expression of c-Myc protein,tumor cell proliferation in vitro,apoptosis and cell cycle analysis.RESULTS: Ad-Asc-myc was obtained with the titer of 2×10¹² pfu/L.Ad-Asc-myc down-regulated the expression of c-Myc protein,Ad-Asc-myc or caffeine enhanced the effects of 2.0,5.0 mg/L cisplatin on MG-63 cells.Moreover,Ad-Asc-myc combined with caffeine significantly enhanced this effects,not only on cisplatin-induced apoptosis,but also on tumor cells proliferation in vitro.The expression of bcl-2 was downregulated,bax were upregulated,while there was no change in the expression of E2F-1.FCM analysis showed that cisplatin treatment induced a block in S phase,and caffeine reversed this block and speeded up the progression of cells out of the S phase.Ad-Asc-myc induced obvious G₂/M phase arrest in transfected cells.CONCLUSION: Ad-Asc-myc combined with caffeine may enhance apoptosis-induced and chemotherapy effects of osteosarcoma MG-63 cells to cisplatin.     

Alteration of efferent system functions in noise-induced hearing loss patients

AIM:To investigate the changes of efferent system functions in noise-induced hearing loss (NIHL) patients and find out a method of clinic diagnosis for NIHL.METHODS:The amplitudes of distortion product otoacoustic emission were measured with and without contralateral broad-band noise using Celesta-503 otoacoustic emission analyzer. The efferent system functions were evaluated by the amplitudes of contralateral suppression.RESULTS:The contralateral suppressions in NIHL patients were significant lower than those in control group in low frequency (0.75 kHz and 1 kHz) of DP-gram and low level primary tone in 2 kHz input/output function. There were no significant differences in contralateral suppressions of 4 kHz and 6 kHz input/output function between NIHL patients and control group.CONCLUSION:The contralateral suppressions in NIHL patients are lower than those in normal hearing subjects and the measurements of efferent system functions could be used in early detection and clinic diagnosis for NIHL.     

烟碱乙酰胆碱受体及其与新烟碱类相互作用的研究进展

对烟碱乙酰胆碱受体(nAChRs)的结构与功能、配体结合部位、门控机理以及与新烟碱类的相互作用进行了综述,并对nAChRs亚基基因突变和敲除对新烟碱类和多杀菌素敏感性的影响进行了讨论。nAChRs在脊椎动物和昆虫的胆碱能突触的快速神经传递中起着重要作用,其在昆虫中仅存在于中枢神经系统(CNS)中,而在脊椎动物中同时存在于CNS和神经肌肉连接处。nAChRs是新烟碱类杀虫剂、多杀菌素和杀螟丹的作用靶标。肌肉和CNS中的nAChRs是一个由两个α和三个非α(β,γ和δ)亚基组成的异数五聚体,该受体主要有三部分:一个在细胞外发现的区域(胞外区)、一个位于膜内的区域(跨膜区),另一个是位于细胞内的区域(胞质区)。每个亚基(从N-C端)都具有一个包含乙酰胆碱(ACh)结合部位的细胞外结构域;4个跨膜结构域(M1~4),其中M2的大部分氨基酸位于离子通道的内壁;一个胞质噜扑(loop)和一个胞外C端。通道门位于孔道内的疏水区。ACh结合部位位于天然和功能受体的两个亚基的界面,是由一个亚基的3个噜扑(A-C)和另一个亚基的3个噜扑(D-F)构成。每当受体与ACh(或其他激动剂)分子结合时,M2 α螺旋体的构象发生改变,使通道开启,处于阳离子传导状态,直至一个或两个激动剂分子从结合口袋解离,通道才关闭。如果激动剂一直存在,并反复结合,则通道处于脱敏状态。nAChRs与新烟碱类的各种选择性作用取决于新烟碱类的结构以及nAChRs的亚基组成。     

浅谈我院图书馆期刊的管理

分析了漳州城市职业学院图书馆期刊管理存在的问题,并提出了建立合理的期刊管理模式,准确定位与形成特色,充分开发期刊资源,加强期刊管理人员队伍的业务素质建设等建议.     

芽苗期低温对玉米生长的影响及抗逆栽培措施

芽苗期低温冷害是影响玉米分布和稳产高产的制约因素之一,如何通过栽培技术措施提高玉米的抗寒性是玉米生产过程中亟待解决的问题。本研究综述了芽苗期低温对玉米生长形态和生理生化的影响,并对相关的抗逆栽培措施进行了介绍和评价,以期为抗低温栽培提供可行的思路。     

家蚕一代杂交种成品卵微粒子病检疫抽样检查存在问题及解决方案

利用近年来集团抽样检查接收概率函数的研究成果,分析了家蚕一代杂交种成品卵微粒子病检疫抽样检查在信赖度的估算、集团检出率的考虑和样本量大小等方面存在的问题,提出了成品卵微粒子病检疫抽样检查方案制定的基本原则和相应的改进方案。新方案考虑了集团检出率、样本的代表性等问题,通过增加检验集团内的个体数减少了检验工作量,使消费者风险和生产者风险都得到有效控制。     

鸭传染性浆膜炎疫苗的研究

用从浙江省分离鉴定的鸭疫里氏杆菌RA-J、RA-L菌株研制疫苗，采用改进的液体培养和鸭胚培养工艺，抗原含量分别达120-186亿CFU／ml和280-310CFU／ml，免疫0.5ml/只，2MLD强毒攻击，平均保护率达94.2％（48／52），免疫后第7天保护率达80％（16／20），10天达93.8％（15／16），疫苗在4℃-8℃条件下保存7个半月和1年的保护率达90％和85％。野外扩大试验和临床推广试用236万羽份表明，效果良好。     

盐酸环丙沙星在患子宫内膜炎奶牛子宫内给药的药物浓度

本研究以反相高效液相色谱为定量分析手段，选用5头患子宫内膜炎的奶牛，通过子宫内灌注盐酸环丙沙星（2.5 g/头），研究了盐酸环丙沙星在患子宫内膜炎奶牛体内的药物动力学规律。以二氟沙星为内标，血浆样品经甲醇沉淀蛋白，离心，经针头式过滤器处理，用反相高效液相法测定其中盐酸环丙沙星的浓度。 色谱条件为：ODS-1C₁₈柱；测定流动相为0.015 mol/L四丁基溴化铵溶液-乙腈（92∶8，V/V），pH为3.0；流速为1.0 ml/min；荧光检测器，激发波长（λex）278 nm，发射波长（λem）465 nm。通过采用MCPKP房室分析程序，分析血中浓度 时间数据，发现有3头奶牛血样药时数据符合无吸收三室开放模型。其血样中主要药动学参数为：T_1/2α为0.916 h、T_1/2β为49.20 h、AUC高达7.6296 mg/L·h、Clβ为1.582 L/kg·h，β为0.642 h^-1。有2头奶牛血样药时数据符合一级吸收二室开放模型。其主要药动学参数为：T_1/2α为1.26 h、T_1/2β为9.2 h、AUC高达28.336 mg/L·h，β为0.3571 h^-1。试验结果表明，盐酸环丙沙星子宫给药吸收快，分布广，消除慢。     

树立科学发展观构建农民增收长效机制

用科学发展观统领农业和农村经济工作的全局,构建农民增收的长效体系:以农民减负、农业支持保护和农村社会保障政策为内容的政策体系,用制度保证增收;以效能环境、知识环境和平安环境为内容的环境体系,以环境促增收;以劳务市场和农业营销市场为内容的市场体系,在市场中实现增收.