中段尿在常温下保存时间对培养结果的影响研究

目的 探讨临床尿液标本不同放置时间对细菌培养结果的影响,明确尿液标本合理保存时间,加强对标本细菌培养前的保存时间控制.方法 随机选取114份患者尿液标本,比较其在新鲜尿液即刻培养结果和室温(22 ～25℃)的环境中各放置0.5、1、2、3、4和5h等不同时间点细菌培养结果的分离率差异,采用样本率与总体率(新鲜尿液培养的分离率)的差别检验(|u|和P)分析其是否具有统计学意义.结果 新鲜尿液即刻培养与放置0.5h培养结果分离率差异无统计学意义(38.6％);之后随放置时间延长分离率逐渐升高,2h接种标本分离率为43％,差异无统计意义(|u| =0.9489,P ＞0.05);放置3、4和5h后接种标本分离率分别为50.9％、55.3％和63.2％,呈显著增高(|u|值分别为2.627、3.586和5.446,P值均小于0.01).结论 在常温下不同的保存时间对培养结果有着重要影响,尤其在2h后影响更为显著.准确有价值的培养结果,与标本合理的存放时间有极大的关系,加强尿液培养前阶段的保存时间控制非常重要.     

福尔马林对固定标本DNA提取和扩增的影响

福尔马林被广泛应用于生物标本的长期保存。由于福尔马林可能影响标本DNA的质量,因此需要对福尔马林固定标本DNA的提取和扩增过程进行改进。影响从福尔马林保存标本中提取的DNA质量的主要因素包括福尔马林导致的DNA与蛋白质之间、蛋白质与蛋白质之间、DNA与DNA之间的交联,福尔马林溶液的化学成分、pH值及浓度,标本保存的时间和温度,标本保存部位等。本文总结了目前常用的对标本DNA提取和扩增过程的改进措施及其优点。     

一种半永久玻片标本的制备方法

这里介绍一种用蔗糖液制备半永久玻片标本的方法。用这种蔗糖液制备半永久玻片标本研究染色体是很方便的和有实际意义的。这种用蔗糖液制备的半永久玻片标本,可以保存较长时间(一年或更长)。蔗糖液的制备方法取40克蔗糖(化学纯)溶解在60毫升水中,并加热至沸,直至溶液总体积减少了1/4时为止。为避免蔗糖液冷却后出现结晶,要向蔗糖液滴入2—3滴香柏油,细心搅匀,然后再加0.2克苯酚结晶,该糖液可保存一个月以上。花药制片方法 1.从经卡诺固定剂(95％酒精:冰醋酸3:1)固定的保存在70％酒精中的花序上取出一些花药,用醋酸地衣红色液(醋酸洋红、醋酸间     

保存原色的小鱼标本的制作

许多年来在研究胎生的现赏鱼类工作时,我们曾给自己定了一个寻找保存蒐集的鱼类原色方法的任务。大家知道,通常把水生动物保存于酒精或福尔马林溶液中的方法,标本常要迅速褪色,并且,照例只有黑色色素被保存下来。在养殖胎生鱼时,有时遇到稀有的颜色的组合,想要保存它们,但是我们不晓得保存浸渍标本颜色的可靠方法。在1938年我们采用过一种制备鱼类干标本的方法,在保存原色方面得到了良好的结果。我们拿刚死     

陈旧标本DNA提取方法

对于自然环境中的或长期保存的动物标本,由于保存环境不良或保存时间过长,DNA提取的难度较大。受标本保存时间和损害程度等因素影响,导致实验结果的不稳定性加强,对于同一标本需要反复实验。为了提高DNA提取效率,节省实验成本,现对陈旧损坏标本的DNA提取方法进行综述。     

乳腺肿瘤组织标本库与数据库的建立及信息化管理

目的:随着基础和临床研究的深入开展,拥有完整基因信息的组织标本成为了肿瘤研究工作的基础.建立电子信息化管理的乳腺肿瘤组织标本库和数据库,为临床和科研收集、保存和管理标本资源.方法:标准化收集手术切除的乳腺肿瘤组织、正常腺体组织,以及患者血液标本,预处理后保存于-80℃冰箱中.每3个月从标本库中随机抽取5例标本,提取标本的总RNA,琼脂糖凝胶电泳验证总RNA质量;运用免疫组织化学法(Immunohistochemistry,IHC)检测标本中人表皮生长因子-2(Human epidermal growth factor receptor,HER-2 or c-erbB-2)和Ki67的表达,并与术后免疫组化结果进行比较.同时利用Epidata软件管理乳腺肿瘤组织标本库.结果:收集恶性肿瘤507例,良性肿瘤212例,血液标本9347份,并建立了一套高效的信息化管理系统.总RNA电泳结果显示28 S和18S亚基条带清晰明亮,5S条带很弱,表明标本中的RNA质量较高,无降解.免疫组化结果显示标本中的HER-2和Ki67的表达与术后免疫组化结果情况吻合,存储的标本质量良好.结论:建立的实验标本收集、储存流程是有效可行的,收集的标本质量是可靠的,管理方法是高效实用的,为乳腺肿瘤基础和临床研究提供质量可靠的标本来源,可为乳腺肿瘤研究提供良好的服务平台.     

中国一新纪录种--缅北原矛头蝮(爬行纲,蛇亚目,蝰科)

记述了采自西藏Protobothrops属标本1条,该蛇原报道于缅甸北部,所获标本为中国新纪录种.标本保存在沈阳师范大学化学与生命科学学院标本馆.     

库蠓属二新种记述(双翅目,蠓科)

报道了我国西北地区库蠓属Culicoides2新种 ,多色库蠓CulicoidesmultifariousLiu ,GongetZhang,sp.nov.和崎岖库蠓CulicoidessalebrosusLiuetShi,sp.nov.。正模标本保存在北京医学昆虫标本馆 ,副模标本保存在兰州军区军事医学研究所     

台湾天牛新种林氏直脊天牛描述(鞘翅目,天牛科,沟胫天牛亚科,楔天牛族)

描述了台湾天牛新种林氏直脊天牛,给出了成虫整体彩色照片和外生殖器照片,并提供了生态照片.正模标本保存在台湾国立自然科学博物馆,副模标本分批保存在中国科学院动物研究所及数个私人收藏馆.     

水杉属和红杉属化石叶表皮鉴定参照系的特殊性

杉科植物的许多属种在小枝的形态和叶片排列上相似,而杉科植物的化石标本多保存为枝叶形式。表皮的特征作为压型化石枝叶标本细胞信息的重要来源,甚至是惟一来源。一直作为杉科植物化石分类鉴定的主要依据。水杉和北美红杉分别是水杉属和红杉属植物化石的惟一现存最近亲缘种,以往关于北美红杉的气孔分布和排列等方面的报道存在分歧,根据作者的研究,北美红杉的表皮特征变异幅度非常广。水杉的气孔分布也与以往报道有差异。利用表皮的特征鉴定杉科植物化石时;不同的处理方法和处理时间,角质层的完整程度和观察数量等均可以影响植物表皮特征的正确获取。     

Imaging hydrated microbial extracellular polymers: comparative analysis by electron microscopy

Microbe-mineral and -metal interactions represent a major intersection between the biosphere and geosphere but require high-resolution imaging and analytical tools for investigation of microscale associations. Electron microscopy has been used extensively for geomicrobial investigations, and although used bona fide, the traditional methods of sample preparation do not preserve the native morphology of microbiological components, especially extracellular polymers. Herein, we present a direct comparative analysis of microbial interactions by conventional electron microscopy approaches with imaging at room temperature and a suite of cryogenic electron microscopy methods providing imaging in the close-to-natural hydrated state. In situ, we observed an irreversible transformation of the hydrated bacterial extracellular polymers during the traditional dehydration-based sample preparation that resulted in their collapse into filamentous structures. Dehydration-induced polymer collapse can lead to inaccurate spatial relationships and hence could subsequently affect conclusions regarding the nature of interactions between microbial extracellular polymers and their environment.     

The World is a Natural Laboratory,and Social Media is the New Petri Dish

Many high‐priority and high‐interest species are challenging to study due to the difficulty in accessing animals and/or obtaining sufficient sample sizes. The recent explosion in technology, particularly social media and live webcams available on the Internet, provides new opportunities for behavioral scientists to collect data not just on our own species, as well as new resources for teaching and outreach. We discuss here the possibility of exploiting online media as a new source of behavioral data, which we termed ‘video mining’. This article proposes epidemiological and ethological field techniques to gather and screen online media as a data source on diverse taxa. This novel method provides access to a rich source of untapped knowledge, particularly to study the behavior of understudied species or sporadic behaviors, but also for teaching or monitoring animals in challenging settings.     

Tandem High-pressure Freezing and Quick Freeze Substitution of Plant Tissues for Transmission Electron Microscopy

Since the 1940s transmission electron microscopy (TEM) has been providing biologists with ultra-high resolution images of biological materials. Yet, because of laborious and time-consuming protocols that also demand experience in preparation of artifact-free samples, TEM is not considered a user-friendly technique. Traditional sample preparation for TEM used chemical fixatives to preserve cellular structures. High-pressure freezing is the cryofixation of biological samples under high pressures to produce very fast cooling rates, thereby restricting ice formation, which is detrimental to the integrity of cellular ultrastructure. High-pressure freezing and freeze substitution are currently the methods of choice for producing the highest quality morphology in resin sections for TEM. These methods minimize the artifacts normally associated with conventional processing for TEM of thin sections. After cryofixation the frozen water in the sample is replaced with liquid organic solvent at low temperatures, a process called freeze substitution. Freeze substitution is typically carried out over several days in dedicated, costly equipment. A recent innovation allows the process to be completed in three hours, instead of the usual two days. This is typically followed by several more days of sample preparation that includes infiltration and embedding in epoxy resins before sectioning. Here we present a protocol combining high-pressure freezing and quick freeze substitution that enables plant sample fixation to be accomplished within hours. The protocol can readily be adapted for working with other tissues or organisms. Plant tissues are of special concern because of the presence of aerated spaces and water-filled vacuoles that impede ice-free freezing of water. In addition, the process of chemical fixation is especially long in plants due to cell walls impeding the penetration of the chemicals to deep within the tissues. Plant tissues are therefore particularly challenging, but this protocol is reliable and produces samples of the highest quality.     

Horizontal slice preparation of the retina

Traditionally the vertical slice and the whole-mount preparation of the retina have been used to study the function of retinal circuits. However, many of retinal neurons, such as amacrine cells, expand their dendrites horizontally, so that the morphology of the cells is supposed to be severely damaged in the vertical slices. In the whole-mount preparation, especially for patch-clamp recordings, retinal neurons in the middle layer are not easily accessible due to the extensive coverage of glial cell (Mueller cell) s endfeets. Here, we describe the novel slicing method to preserve the dendritic morphology of retinal neurons intact. The slice was made horizontally at the inner layer of the retina using a vibratome slicer after the retina was embedded in the low-temperature melting agarose gel. In this horizontal slice preparation of the retina, we studied the function of retinal neurons compared with their morphology, by using patch-clamp recording, calcium imaging technique, immunocytochemistry, and single-cell RT-PCR.     

实验准备及技术人员在提高医学微生物学教学质量中的作用

实验课是现代医学微生物学课程中不可或缺的部分。然而,在考虑医学微生物学实验教学改革时,我们往往忽略了实验课教学准备工作及实验技术人员在高质量完成教学任务中的重要性。本文结合复旦大学2000年前、2000-2010年及现阶段医学微生物学实验教学改革情况,分析并讨论实验课教学准备工作必须考虑的问题及所需实验条件,提出实验技术人员素质及实验课教学准备在保证医学微生物学实验教学质量中的重要性,为医学微生物学实验教学改革提供借鉴。     

做好实验准备工作,提高微生物学实验教学质量

完善的微生物学实验准备工作是确保实验成功的开始,也是提高微生物学实验教学质量的重要环节。从加强实验室管理,制定详细的实验准备内容,严格进行实验预做等方面介绍做好微生物学实验准备工作的经验,为提高实验教学质量,培养具有创新能力的人才提供参考和借鉴。     

Comparison of Preparation Methods of Bacterial Cell-Mineral Aggregates for SEM Imaging and Analysis Using the Model System of Acidovorax sp. BoFeN1

Innovative microanalytical methods are valuable tools in geomicrobiology. They often require the use of dried samples, demanding a challenging sample preparation. Since geomicrobiological samples typically have a strongly heterogeneous composition, choosing a preparation method is not straightforward. We therefore compared how different drying methods (critical point drying, hexamethyldisilazane drying, air drying and freeze drying) influence the structure of bacterial cell-mineral aggregates. Each method proved suitable for a specific purpose, but none was able to completely preserve the sample structure. Additional information was obtained on surface alterations by sputter coating and on preservation of extracellular polymeric substances during resin embedding.     

Protocol of single cells preparation for time of flight secondary ion mass spectrometry

There are several techniques like time of flight secondary ion mass spectrometry (ToF SIMS) that require a special protocol for preparation of biological samples, in particular, those containing single cells due to high vacuum conditions that must be kept during the experiment. Frequently, preparation methodology involves liquid nitrogen freezing what is not always convenient. In our studies, we propose and validate a protocol for preparation of single cells. It consists of four steps: (i) paraformaldehyde fixation, (ii) salt removal, (iii) dehydrating, and (iv) sample drying under ambient conditions. The protocol was applied to samples with single melanoma cells i.e. WM115 and WM266-4 characterized by similar morphology. The surface and internal structures of cells were monitored using atomic force, scanning electron and fluorescent microscopes, used to follow any potential protocol-induced alterations. To validate the proposed methodology for sample preparation, ToF SIMS experiments were carried out using C₆₀⁺ cluster ion beam. The applied principal component analysis (PCA) revealed that chemical changes on cell surface of melanoma cells were large enough to differentiate between primary and secondary tumor sites.     

Microwave irradiation for fixation and immunostaining of endothelial cells in situ

Using microwave irradiation during tissue fixation and immunostaining reduces sample preparation time and facilitates penetration of fixatives and antibody solutions into the tissues. This results in improved fixation and reduction of non-specific binding of antibodies, respectively. Experimental analyses of endothelial cells in blood vessels in situ have been limited because of the difficulty of tissue preparation. We report here a technique using intermittent microwave irradiation for blood vessel fixation and immunostaining the fixed tissues. Intermittent microwave irradiation during fixation reduced blood vessel contraction and resulted in well preserved morphology of blood vessels, especially the endothelial cells. Microwave irradiation also reduced non-specific binding of fluorescein-labeled antibodies. These microwave irradiation-assisted techniques are useful for analysis of endothelial cell function and for pathological study of blood vessels in situ.