“标本瓶封口法”的一种新尝试

标本瓶口的封合剂是很多的,按性质可分为热封合剂和冷封合剂两类。现在一般技术操作书上介绍的热封合剂较多,它有—个缺点,需要加热比较麻烦,所以一般多喜欢用冷封合剂封瓶口,手续此较简单。过去我们用加拿大树膠,效果很好,但是实际操作中发现加拿大树膠却封不住装冬青油的透明标本瓶盖,因为冬青油的蒸汽可以溶解它,是否可以不用“松香     

《自然-方法学》：培养多能干细胞新系统建立

研究人员研制出了一种简化的、化学成分明确的培养系统，可用于人类多能干细胞的生长，新成果发表在日前在线出版的《自然-方法学》期刊上。新方法很重要，既可用于标准化来自不同实验室的报告结果，也可最终用于这些细胞的临床应用。     

《自然-方法学》：培养多能干细胞新系统建立

研究人员研制出了一种简化的、化学成分明确的培养系统，可用于人类多能干细胞的生长，新成果发表在日前在线出版的《自然-方法学》期刊上。新方法很重要，既可用于标准化来自不同实验室的报告结果。也可最终用于这些细胞的临床应用。     

漫话药用植物资源

从传统意义上说，药用植物资源是指中医在传统上用于防病治病的中药材植物资源。随着时间的推移，其包含的药材种类范围在不断扩大，现在通常泛指在我国自然资源中存在的一切可用于防病治病的植物种类。     

一种简便适用的蛋白质水解方法

进行蛋白质的氨基酸的组成分析时,蛋白质水解液的制备是十分重要的一步。样品水解的好坏直接影响测定结果的准确性。经典水解条件是:6N HCI,110℃在封管条件下恒温水解24小时。在这条件下进行水解,蛋白质分子中的Ser,Thr,Trp,Cys,Tyr,Met仍可能因氧化、降解等反应影响回收率。为此,要求在封管时减压或充氮以提高回收率,但这又需要特殊装置,国内一般实验室不具备这样的条件。我们试用1.5ml聚丙烯带盖的离心管代替玻璃指管进行蛋白质水解。实验结果表明用这二种管子水解结果相同,而使用聚丙烯离心管可以免去加热封管等步骤,减少了样品的损     

杀虫不用药物理方法好

在农作物生产和采后处理中经常使用的董蒸剂一澳代甲烷既有毒又易挥发，近来研究表明不仅破坏大气臭氧层，也影响使用者的健康，可能引起癌症出现。据（加州农业）报道，为保护大气臭氧层，减少空气污染，美国科学家们正在研究使用电磁能以替代化学药剂。目前，一支由化学家、植物病理学家和昆虫学家组成的研究小组已开发出三种行式的电磁能在三种不同场合使用：射频法用于温室土壤消毒；微波用于大面积田间处理，杀死土壤害虫；紫外光用于农作物采后害虫防治。射频法和紫外光法已获成功，微波法正在试验用于大田播前处理，这三种方法都能杀…     

NEJM：干细胞过度生长或造成癌症

美国《新英格兰医学杂志》（NEJM）8月11日刊登明尼苏达大学研究者约翰·瓦格纳和雅各布·托拉尔的研究报告，首次显示骨髓干细胞可用于治疗皮肤病和上消化道系统疾病。但是，干细胞用于治病却一直有个让人不安的担心：控制不好。治病所用的干细胞就有可能演变为难以制约的肿瘤，尤其是全能分化的胚胎干细胞，如果不受控制地生长，会造成癌症。     

大网膜脂质血管生长因子对几种细胞增殖的影响

大网膜是人和其它动物腹腔中功能十分复杂的组织，许多外科界学者认为大网膜除了具有消除炎症外，还有促进血管生长作用，因此在外科学中广泛应用，如用于脑缺血的治疗。最近国内外许多学者认为其具有促进神经细胞生长作用，用于神经损伤的治疗，并取得了一定的疗效。但多...     

长效人白细胞介素2

rhIL-2是最早开发的基因工程药物之一．已广泛用于各种肿瘤和病毒感染疾病的治疗，尤其是在肾癌和癌性积液治疗方面疗效明显，已被列为国家基本药物品种。近年来，IL-2用于HIV感染者治疗的临床研究也取得了重要进展。但IL-2的血浆半衰期仅为85min，治疗期间为维持药效需大剂量频繁输注或注射，这不仅大大增加了副反应和病人的痛苦，而且由于血药浓度波动较大，也影响了疗效的发挥。     

国外科技简讯

艾滋病的克星──短绒毛钩藤茜草科藤本灌木短绒毛钩藤（Uncarlatomentosa）原产于南美亚马逊地区热带雨林，是当地传统的药用植物。由于它可用于治疗多种疾病，最近被列为美国最畅销的“十大天然药用植物”之一。根据最近美国和其他国家的研究，短绒毛钩藤是一种强烈的免疫刺激物，可以抵抗细菌和病毒。它在医药上的应用范围很广，不仅有抗炎作用，可以治疗关节炎和胃炎，而区可以治疗系统性念珠菌病、狼疮、过敏性变态反应、支气管炎、疙疹、糖尿病、低血糖、血循环障碍例如高血压和静脉曲张。同时也可用于避孕。甚至还可用于预防和治疗…     

Operation of a multichannel microcalorimetry system in the micro-submicrowatt region: some methodological aspects

Monitoring heat flux values below approx. 4 microW requires in microcalorimetry non-standard experimental procedures in order to achieve high accuracy and reproducibility. With 5 ml ampoules, stable baselines are reached in 70 min if a three-level pre-thermostating procedure is used and if the gas phase above the liquid is reduced to 0.5 ml or less. A pairwise procedure of reference/measuring ampoules is used. Autoclaved sealing material of teflon, sterilized stainless steel ampoules in contact with a standard cell medium and culture plates of polystyrene do not contribute to measured heat flux. Further, we found that a standard cell culture medium develops a significant thermal heat flux, 0.10 microW.ml-1, probably reflecting an oxidation process in the medium itself.     

A Disposable Anaerobic System Designed for Field and Laboratory Use

A disposable anaerobic system which is characterized by its light weight and its compactness is described. The system consists of a multilayer plastic bag with a unique sealing device. A collapsible impregnated cardboard container is fitted with a catalyst and holders for a disposable hydrogen generator and an anaerobic indicator. The catalyst is active at room temperature and requires no heat activation. This system, which lends itself readily to compact storage, quick assembly, and ease of operation, is disposable after use.     

Collector device for apparatus hookup connections in microbiological manufacture]

A collector device developed on the basis of a holding tank is discussed. The working principle of the device, its characteristics and advantages as applied to microbiological industry are described. The use of the collector devices in the assembly diagrams of the apparatus provides reduction of the number of the piping fittings, the pipe-line length, the number of the sealing elements, heat evolution into the environment, and time of the apparatus servicing.     

风和光对东北鼢鼠堵洞行为的影响

东北鼢鼠的堵洞行为,是其适应地下生活一种行为反应。通常认为是其避光怕风的生态习性促使其产生堵洞行为,但相关的实验证据较为缺乏。为验证这一观点的正确性以及为进一步探究其堵洞行为产生的机理提供科学依据,本研究于2014年8月在内蒙古呼伦贝尔草甸草原进行了野外试验。试验采用2×2列联表设计,将风、光因子组合为4个处理,分别为,风光都进入洞道、风进入洞道光不进入洞道、风不进入洞道光进入洞道、风光都不进入洞道。并通过自行设计的专利“风光隔离器”使每个处理达到了试验的要求。试验随机选取68只东北鼢鼠作为试验样本,并将样本平均分配到4个处理中进行试验,对堵洞与否进行记录。通过Shannon信息量互信息法、卡方独立性检验分别对风、光因子的独立性、风光单因子与堵洞行为的关系进行了分析。结果表明：就堵洞而言,风光因子是独立的,不存在交互作用（I=7.22×10-5）;风、光单因子与东北鼢鼠的堵洞次数差异不显著（P﹥0.05）。野外试验表明,东北鼢鼠的堵洞行为与风和光无关。     

Anatomical repair of nerve membranes in crushed mammalian spinal cord with polyethylene glycol

Acute damage to axons is manifested as a breach in their membranes, ion exchange across the compromised region, local depolarization, and sometimes conduction block. This condition can worsen leading to axotomy. Using a novel recording chamber, we demonstrate immediate arrest of this process by application of polyethylene glycol (PEG) to a severe compression of guinea pig spinal cord. Variable magnitudes of compound actions potentials (CAPs) were rapidly restored in 100% of the PEG-treated spinal cords. Using a dye exclusion test, in which horseradish peroxidase is imbibed by damaged axons, we have shown that the physiological recovery produced by polyethylene glycol was associated with sealing of compromised axolemmas. Injured axons readily imbibe horseradish peroxidase—but not following sealing of their membranes. The density of nerve fibers taking up the marker is significantly reduced following polyethylene glycol treatment compared to a control group. We further show that all axons—independent of their caliber—are equally susceptible to the compression injury and equally susceptible to polyethylene glycol mediated repair. Thus, polyethylene glycol—induced reversal of permeabilization by rapid membrane sealing is likely the basis for physiological recovery in crushed spinal cords. We discuss the clinical importance of these findings.     

Podosome and sealing zone: specificity of the osteoclast model

The bone resorption function of osteoclasts is dependent on the integrity of the actin cytoskeleton. Depending on the substratum upon which the osteoclasts are spread, there are two different structures of actin known as podosomes and the sealing zone. To understand the specific properties and relationship of podosomes and the sealing zone, we used live-cell imaging of cultured osteoclasts. When cultured on extracellular matrix components, podosomes in these cells are organized in higher-ordered structures. These are clustered podosomes that will arrange later into dynamic short-lived rings which finally expand to the cell periphery to form a stable long-lived podosome belt in fully differentiated cells. In osteoclasts, this specific podosome patterning is under the control of microtubules (MTs). Indeed, nocodazole treatment does not affect podosome formation but only the transition between clusters/rings and belts. During this transition, MTs accumulate a specific post-translational modification of tubulin by acetylation. This process is repressed by an inhibitory pathway involving the GTPase Rho, its effector mDIA2 and the recently discovered tubulin deacetylase HDAC6. The specific function of this acetylation is still unknown but is also observed in active osteoclasts forming a sealing zone which is also MT dependent. Thus, it appears that the podosome belt is reminiscent of the sealing zone. Indeed, podosome belts and sealing zones are characterized by their overall stability. Despite their similar behavior, a sealing zone is not formed by fusion of podosomes. The formation of a podosome belt or a sealing zone is controlled by the external environment. Indeed, only the bone mineral fraction, known as apatite crystal, is able to induce sealing zone formation in mature osteoclasts. Contact of osteoclasts with apatite stimulates the non-receptor tyrosine kinase c-Src and the GTPase Rho in order to form the sealing zone. As we will discuss in this review, it appears that podosomes and the sealing zone are strikingly linked.     

c-Src-mediated Phosphorylation of Thyroid Hormone Receptor-interacting Protein 6 (TRIP6) Promotes Osteoclast Sealing Zone Formation

Osteoclasts resorb bone through the formation of a unique attachment structure called the sealing zone. In this study, a role for thyroid hormone receptor-interacting protein 6 (TRIP6) in sealing zone formation and osteoclast activity was examined. TRIP6 was shown to reside in the sealing zone through its association with tropomyosin 4, an actin-binding protein that regulates sealing dimensions and bone resorptive capacity. Suppression of TRIP6 in mature osteoclasts by RNA interference altered sealing zone dimensions and inhibited bone resorption, whereas overexpression of TRIP6 increased the sealing zone perimeter and enhanced bone resorption. Treatment of osteoclasts with lysophosphatidic acid (LPA), which phosphorylates TRIP6 at tyrosine 55 through a c-Src-dependent mechanism, caused increased association of TRIP6 with the sealing zone, as did overexpression of a TRIP6 cDNA bearing a phosphomimetic mutation at tyrosine 55. Further, LPA treatment caused increases in osteoclast fusion, sealing zone perimeter, and bone resorptive capacity. In contrast, overexpression of TRIP6 containing a nonphosphorylatable amino acid residue at position 55 severely diminished sealing zone formation and bone resorption and suppressed the effects of LPA on the cytoskeleton. LPA effects were mediated through its receptor isoform LPA(2), as indicated by treatments with receptor-specific agonists and antagonists. Thus, these studies suggest that TRIP6 is a critical downstream regulator of c-Src signaling and that its phosphorylation is permissive for its presence in the sealing zone where it plays a positive role in osteoclast bone resorptive capacity.     

乙醇与常规肝素封管在血液透析长期留置导管中的比较研究

目的:比较乙醇封管和常规肝素封管两种方法在长期留置导管维持性血液透析患者中的效果,为临床维持性血液透析患者深静脉置管患者封管方式提供依据。方法:选择长期留置导管的维持性血透患者28例作为研究对象,随机分成实验组和对照组,实验组采用乙醇封管,对照组采用常规肝素封管,观察两组导管相关菌血症及血栓的发生情况及患者微炎症状态,观察48周。结果:乙醇封管组导管相关性感染及炎症指标明显降低,尤其在25-48周(P<0.05);两组患者血栓发生率无明显差别(P>0.05)。结论:乙醇封管比常规肝素封管可有效降低维持性血液透析患者导管相关感染的发生率,且不易导致管腔内凝血,是一种安全、有效的封管方式。     

Pathways for plasmalemmal repair mediated by PKA, Epac, and cytosolic oxidation in rat B104 cells in vitro and rat sciatic axons ex vivo

Plasmalemmal repair (sealing) is necessary for survival of damaged eukaryotic cells. Ca²⁺ influx through plasmalemmal disruptions activates pathways that initiate sealing, which is commonly assessed by exclusion of extracellular dye. These sealing pathways include PKA, Epac, and cytosolic oxidation. In this article, we investigate whether PKA, Epac, and/or cytosolic oxidation, activate specific proteins required to produce a plasmalemmal seal. We report that toxin cleavage of proteins required for neurotransmitter release (SNAP‐25), inhibition of Golgi trafficking (with Brefeldin A: Bref A) or inhibition of N‐ethylmaleimide sensitive factor (NSF) all decrease sealing of rat B104 hippocampal cells with transected neuritis in vitro. Epac, but not PKA or cytosolic oxidation, partly overcomes the decrease in sealing produced by cleavage of SNAP‐25. PKA and increased cytosolic oxidation, but not Epac, can partly overcome the decrease in sealing due to Bref A. PKA, Epac, and/or cytosolic oxidation cannot overcome NSF inhibition. Substances that affect plasmalemmal sealing of B104 neurites in vitro have similar effects on plasmalemmal sealing in rat sciatic axons ex vivo. From these and other data, we propose a model of plasmalemmal sealing having three redundant, evolutionarily conserved, parallel pathways that all converge on NSF. © 2011 Wiley Periodicals, Inc. Develop Neurobiol, 2012     

Apatite-mediated actin dynamics in resorbing osteoclasts

The actin cytoskeleton is essential for osteoclasts main function, bone resorption. Two different organizations of actin have been described in osteoclasts, the podosomes belt corresponding to numerous F-actin columns arranged at the cell periphery, and the sealing zone defined as a unique large band of actin. To compare the role of these two different actin organizations, we imaged osteoclasts on various substrata: glass, dentin, and apatite. Using primary osteoclasts expressing GFP-actin, we found that podosome belts and sealing zones, both very dynamic actin structures, were present in mature osteoclasts; podosome belts were observed only in spread osteoclasts adhering onto glass, whereas sealing zone were seen in apico-basal polarized osteoclasts adherent on mineralized matrix. Dynamic observations of several resorption cycles of osteoclasts seeded on apatite revealed that 1) podosomes do not fuse together to form the sealing zone; 2) osteoclasts alternate successive stationary polarized resorption phases with a sealing zone and migration, nonresorption phases without any specific actin structure; and 3) apatite itself promotes sealing zone formation though c-src and Rho signaling. Finally, our work suggests that apatite-mediated sealing zone formation is dependent on both c-src and Rho whereas apico-basal polarization requires only Rho.