电磁屏蔽功能胶合板初探

为了赋予木基复合材料电磁屏蔽功能,在脲醛树脂胶中加入碳、石墨等导电单元,制备3层结构的杨木胶合板,研究不同导电单元对胶合板电磁屏蔽效能的影响.结果表明:导电单元的粒度越小,胶合板的电磁屏蔽效能越好,最大可达22 dB,但相关机理和量化关系还有待于深入研究.     

珍贵野生蔬菜蒲公英的有效成分与药理作用

蒲公英中含有胡萝卡素类、三萜类、植物甾醇类、倍半萜内酯类、香豆素类、黄酮类、酚酸类物质；药理研究证明蒲公英具有抑菌、抗内毒素、健胃、利胆、通乳和抗肿瘤等作用。     

薄木贴面装饰板中水份的作用及控制

本文阐述了薄木贴面装饰板生产中水份的调控措施 ,对生产具有一定的指导意义。     

关于漏电保护器误动作的原因分析

本文以单相漏电保护器为例,阐明其几种错误接线的原因,并针对其不同的错误安装接线方法,提出了具体的改进措施。     

Induction of cell proliferation in the rat liver by the short-term administration of ethyl tertiary-butyl ether

In the present study, in continuation of our previous experiment in order to investigate the mode of action (MOA) of ethyl tertiary-butyl ether (ETBE) hepatotumorigenicity in rats, we aimed to examine alterations in cell proliferation, that are induced by short-term administration of ETBE. F344 rats were administered ETBE at doses of 0, and 1,000 mg/kg body weight twice a day by gavage for 3, 10, 17 and 28 days. It was found that the previously observed significant increase of P450 total content and hydroxyl radical levels after 7 days of ETBE administration, and 8-OHdG formation at day 14, accompanied by accumulation of CYP2B1/2B2, CYP3A1/3A2, CYP2C6, CYP2E1 and CYP1A1 and downregulation of DNA oxoguanine glycosylase 1, was preceded by induction of cell proliferation at day 3. Furthermore, we observed an increase in regenerative cell proliferation as a result of ETBE treatment at day 28, followed by induction of cell cycle arrest and apoptosis by day 14. These results indicated that short-term administration of ETBE led to a significant early increase in cell proliferation activity associated with induction of oxidative stress, and to a regenerative cell proliferation as an adaptive response, which could contribute to the hepatotumorigenicity of ETBE in rats.     

Therapeutic antibodies: their mechanisms of action and the pathological findings they induce in toxicity studies

Antibodies can swiftly provide therapeutics to target disease-related molecules discovered in genomic research. Antibody engineering techniques have been actively developed and these technological innovations have intensified the development of therapeutic antibodies. From the mid-1990’s, a series of therapeutic antibodies were launched that are now being used in clinic. The disease areas that therapeutic antibodies can target have subsequently expanded, and antibodies are currently utilized as pharmaceuticals for cancer, inflammatory disease, organ transplantation, cardiovascular disease, infection, respiratory disease, ophthalmologic disease, and so on. This paper briefly describes the modes of action of therapeutic antibodies. Several non-clinical study results of the pathological changes induced by therapeutic antibodies are also presented to aid the future assessment of the toxic potential of an antibody developed as a therapeutic.     

靶向甲型流感病毒血凝素的人源单克隆抗体研究进展

甲型流感病毒感染性强,宿主广泛,主要感染禽类,其次为哺乳动物。当跨物种传染事件发生时,有可能造成流感大流行,因此,对病毒实施及时有效的监控,以及研发抗流感病毒药物刻不容缓。流感病毒表面的糖蛋白血凝素在病毒入侵宿主细胞的过程中发挥了关键的作用,可作为单克隆抗体药物的主要靶点。针对血凝素的单克隆抗体能够有效抑制病毒传播,保护宿主。因此,本文综述了目前报道的针对甲型流感病毒血凝素糖蛋白的人单克隆抗体,为后续抗流感药物的研发提供新的思路和展望。     

Stimulation of acetylcholinesterase activity by triiodothyronine in the brain of Singi fish,Heteropneustes fossilis (Bloch)

Three consecutive days of injections of triiodothyronine (T₃)(0.038, 0.075, 0.15 and 1.54 nmoles/g) significantly elevated the acetylcholinesterase (AchE) activity in the brain of Singi fish, Heteropneustes fossilis (Bloch). The higher doses of 0.075, 0.15 and 1.54 nmoles of T₃/g induced a greater increase in enzyme activity than 0.038 nmoles/g. A T₃ dose of 0.019 nmoles/g was found to be ineffective. The T₃ action on AchE activity was blocked by cycloheximide. Thiourea treatment for 30 days decreased the AchE activity below the control level. This reduced level of the enzyme activity was brought back even above the control level by T₃ injections. It is, therefore, suggested that thyroid hormone is involved in the sustenance of AchE activity in fish brain.     

三种中药提取物体外抗猪繁殖与呼吸综合征病毒的作用

在前期筛选具有抗猪繁殖与呼吸综合征病毒(PRRSV)作用的中药研究基础上,选取药效较好的三种中药：穿心莲、芦根和夏枯草。为进一步研究其有效抗病毒成分,采用MTT 法观察了穿心莲内酯盐、芦根多糖和夏枯草多糖成分对猴肾上皮细胞系(Marc-145) 生长的影响,分别采用阻断、抑制、直接杀灭3种作用方式观察了各成分抗RPPSV感染作用。结果显示：穿心莲内酯盐对细胞最大安全浓度为0.16 mg/mL,芦根多糖为0.575 mg/mL,夏枯草多糖为1.125 mg/mL;芦根多糖在三种方式上均有不同程度的抗PRRSV作用,而穿心莲内酯盐和夏枯草多糖阻断PRRSV作用不明显,抑制和杀灭PRRSV作用明显。结果表明穿心莲内酯盐、芦根多糖和夏枯草多糖均有抗病毒作用,为抗病毒中药的主要药效成分。     

Electromechanical effects of acetylcholine on the atrial tissues of the cultured tilapia (Oreochromis nilotica × O. aureus)

The effects of acetylcholine (ACh) on the action potential and twitch force of atrial tissues isolated from 15 tilapia (Oreochromis nilotica × O. aureus) were studied by means of conventional microelectrode techniques. In isolated whole atrium or sinoatrial tissue, scattered pacemaker-like cells with spontaneous diastolic depolarization were found mainly near the sinoatrial junction but also occasionally throughout the atrial wall. However, most of the atrial cells recorded were myocardial fibers as judged by a stable diastolic potential and a markedly reduced action potential duration (APD) in response to low concentrations of ACh (0.1–1 M). The shortening in APD in atrial myocardial fibers was correlated with a significant fall in twitch force in the atrial preparations. ACh at high concentrations (10–300 M) decreased moderately the APD and the slope of diastolic depolarization of the pacemakers and prolonged the spontaneous cycle length but did not induce hyperpolarization. The negative chronotropic action of ACh was competitively inhibited by atropine, a muscarinic antagonist. The means (± SEM) negative logarithm of the dissociation constant (pK_b or pA₂ value) for atropine against the ACh action on muscarinic receptors were 9.10 (± 0.13) (n = 6), similar to those values obtained in mammalian atria. The present findings indicate that while the negative inotropic effects of ACh in tilapia atria are comparable to those observed in mammalian hearts, unique electrophysiological responses to ACh exist in different types of tilapia atrial cells.