微孔过滤法测定红细胞变形性的统一理论模型

在红细胞悬浮液过滤前后压积不变的合理假设下,并考虑到微孔滤膜堵塞现象,建立了微孔过滤法测定红细胞变形性的统一理论模型－流导模型。该模型利用滤膜相对流导Ｃ与悬浮液滤过体积Ｖ之间的线性关系表达实验结果。利用这一模型,从微孔过滤实验得到了分别反映平均变形性和堵塞信息的两个微观参数;红细胞平均相对过孔阻力β和导致滤膜堵塞的红细胞比例ε。流导模型对各种不同的过滤方法给予统一的描述,对现有的过滤方法或可能出现     

用核孔滤膜过滤法研究红细胞的变形性

正常红细胞有很大的变形能力,因此能够通过比本身小得多的微孔和微血管。若红细胞因病变,变形能力减少,则不能或较难通过上述微孔,这样就会影响血流及红细胞的运氧功能。红细胞通过微孔的能力──可滤过性,能反映出红细胞的变形性。孔径均匀,孔形规则的核孔滤膜是测定红细胞可滤过性的理想滤膜。用它研究红细胞可滤过性,方法简单,能为研究某些缺血性疾病的发生机理提供重要资料。     

全血滤过法测定红细胞变形性的意义

有关红细胞变形性的检验指标,已受到临床的重视。测定红细胞变形性的方法也越来越多。最近,Rohmor 报告目前检查红细胞的变形性的方法有流变镜法、激光衍射法、高速离心法、细胞流过时间分析法、微吸管法、微孔滤膜法和凝胶过滤法等。目前,在国内大多数基层医疗单位采     

浮游植物中叶绿素a提取方法的比较与改进

对水质监测中叶绿素a的提取方法进行改进,采用反复冻融-浸提方法提取叶绿素a,即将过滤水样的滤膜于-20℃冰箱内和室温下反复冻融3～5次后,放进90%丙酮溶液中浸提20h。与标准方法中的研磨法对比,该方法具有人为误差小、稳定性好、结果准确及操作简单安全等优点,适合运用于常规的水质监测。采用该方法时过滤水量对湖水水样的测定结果有影响(P<0.01),对于纯微囊藻液影响不明显(P>0.05)。因此,在对不同叶绿素水平或营养水平的水体采样时,应注意水样的水量。通过方差分析表明该方法中采用醋酸纤维滤膜、微孔滤膜和玻璃纤维滤膜对结果没有显著影响,对这3种滤膜可以进行自由选择。     

海洋异养细菌利用溶解有机碳的定量评估

【目的】惰性溶解有机碳(refractory dissolved organic carbon,RDOC)是海洋总有机碳的主体组分,RDOC在深海中可保存数千年,构成了巨大的碳储库,在调节气候变化中有重要作用。但RDOC的定量评估尚未有统一的标准方法。通过测定环境中能被异养细菌利用的溶解有机碳(biodegradable DOC,BDOC)可以反过来评估RDOC的量。本文对BDOC测定中一些关键步骤进行验证,为制定海洋RDOC评估标准奠定基础。【方法】本文评估了3种过滤方式及5种滤膜对DOC测定的影响,并评估了瓶子效应和稀释效应对细菌生长和DOC利用的影响。【结果】研究发现,(1) GF/F滤膜、GF-75滤膜、聚四氟乙烯(PTFE)滤膜(孔径0.2μm)、聚碳酸酯(PC)滤膜(孔径0.2μm)和聚四氟乙烯材质针孔过滤器(HA)(孔径0.2μm) 5种滤膜不会引入DOC污染;抽滤过滤和重力过滤方式过滤效果稳定、无污染,而在线过滤效果不稳定,易污染;(2)不同大小培养体系(30–480 mL;表面积/体积比为:1.64–0.67 cm–1)之间的细菌生长速率和DOC利用量没有显著性差异;(3)培养体系稀释度越高,细菌生长速率越高,对数生长期细菌丰度及DOC利用量越低。【结论】综合考虑,建议BDOC和RDOC测定实验中采用抽滤过滤的方式及不进行稀释的培养体系;常用的滤膜和培养体积对BDOC评估无显著影响。结合研究结果,我们提出了评估海洋RDOC的方法。     

快速斑点免疫结合试验的研究进展

快速斑点免疫结合试验（ＤｏｔＩｍｍｕｎｏｂｉｎｄｉｎｇＡｓａｙＤＩＢＡ）是８０年代中期发展起来的固相标记免疫测定技术,其原理是以微孔滤膜为载体,通过渗滤或毛细管作用,使抗原抗体快速进行反应检测数分钟完成,阳性结果在膜上出现着色斑点。近年来,利用微孔滤膜的过滤性能或毛细管作用,创造了各种简便快速的ＤＩＢＡ,如斑点酶免疫渗滤试验,斑点金免疫渗滤试验,斑点免疫层析试验,本文对其原理、反应模式、质量控制、发展趋势及应用作一简要综述     

应用微孔滤膜法检测尿液细菌的实验

本文应用微孔滤膜法和标准白金耳直接法平行培养检查了１２８例中段尿。提示在临床细菌检验工作中,一般用于鉴别尿路感染所做的尿液细菌计数采用标准白金耳法为好,因其操作简便,并可取得同样满意的结果。若受感染者正在接受抗菌药物治疗或患侧输尿管梗阻,尿液被过度稀释及某些细菌繁殖力低等因素,均可使每毫升尿液的细菌数小于１０４,如此情况用微孔滤膜法可相对提高阳性检出率。本文应用上述两法检测了奈瑟氏淋菌,其结果说明：微孔滤膜法较白全耳法检出例数明显增高,两者比较有显著差异。     

应用TFF微孔过滤澄清白喉、破伤风毒素培养液及超滤浓缩的试验

用ＴＦＦ微孔过滤系统对白喉、破伤风毒素培养液分别进行了两次澄清过滤试验,澄清过滤后的毒素上清液立即用ＴＦＦ超滤系统浓缩至原培养液体积的１／１０－１／２０。白喉毒素总回收率分别为８６％、７６．６％,破伤风毒素总回收率为９４．１％、９２％。澄清过滤中白喉毒素平均Ｆ１ｕｘ分别为２３．４、１４．３Ｌ／ｍ２／ｈ,破伤风毒素平均Ｆｌｕｘ为２４及２２．９Ｌ／ｍ２／ｈ。结果表明破伤风两次试验有很好的一致性,白喉毒素回收率差别不甚明显,而两次试验Ｆｌｕｘ相差较大,ＴＦＦ微孔过滤系统用于澄清白喉培养液,滤膜使用后的清洗程序仍需改良,以提高膜滤过功能的恢复。     

微滤膜分离提纯苦楝素的研究

通过对不同孔径和材质的微孔滤膜对苦楝提取液过滤分离比较,优选出孔径为0.45μm的聚醚砜微滤膜对苦楝提取液具有良好的过滤性能。确定的膜分离提纯苦楝素优化工艺条件是:在料液浓度为0.374 mg/mL,料液温度35℃,操作压力差为0.08 MPa,循环流量为0.15 L/h,pH=7.0,苦楝素的转移率为99.4%,除杂率为8.3%,通量为147.2 L/m2.h,苦楝素的纯度为由提取液的0.89%,提高到了8.79%。     

破伤风杆菌发酵液澄清过滤试验

目的:考察表面滤器PolysepⅡCGW3和深层滤器Millistak+X0HC用于破伤风杆菌发酵液澄清过滤的效果,选择出满足实际生产要求的滤器。方法:对表面滤器PolysepⅡCGW3采用Vmax试验,对深层滤器Millistak+X0HC采用Pmax试验,通过实验室小规模NFF(常规过滤)试验结果,计算满足实际工艺生产需要的膜面积,并择优进行放大试验。结果:两种滤器均可满足工艺要求,对破伤风毒素吸附甚微。Millistak+X0HC滤器过滤后滤液浊度为2.06NTU,所需最低滤膜面积为1.18m2。PolysepⅡCGW3滤器过滤后滤液浊度为4.76NTU,所需最小滤膜面积为1.29m2。选择PolysepⅡCGW3滤器进行放大试验并与板框滤器进行比较。讨论:根据小量及放大试验结果,综合考虑经济成本、工作时间及操作性,PolysepⅡCGW3滤器较板框滤器更适用于生产。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.