The gastric mucosal barrier: tight junction structure in gastritis and ulcer biopsies

Summary Tight junctions of the human gastric mucosa were examined using quantative freeze-fracture methods. Biopsies examined were from patients with gastric diseases including gastritis, ulcers, and pernicious anemia. No significant differences were seen in strand number or tight junction complex depth among the biopsies analyzed, however, anomalous tight junction structures were observed. Discontinuities in the tight junction complex and hyperplastic tight junctions (extensions of the apical tight junction strands radiating over the lateral plasma membrane) were seen. These alterations were not associated exclusively with either the diagnosis of gastritis or ulcers. However, a higher frequency of tight junction breaks was seen in stomach biopsies diagnosed as gastritis while those diagnosed as ulcers displayed a higher occurrence of hyperplastic tight junctions.     

Effects of dexamethasone on the differentiation of membrane structure in cultured astrocytes.

Astrocytic processes investing vascular structures or forming the surface of mammalian brain have large numbers of orthogonally packed aggregates of intramembrane particles, termed "assemblies." Similar particle aggregates are expressed by astrocytes derived from neonatal rat forebrain in secondary culture, but they are much more uniformly distributed across the membranes of the cultured cells. Dexamethasone, a potent glucocorticoid, affects the differentiation of astrocyte membrane structure in two patterns, depending on the rate of proliferation in the culture. When confluent secondary cultures of astrocytes are exposed to 5 microM dexamethasone, the densities of assemblies increase, and in some cells approach the values present in the glial limitans in vivo. However, when rapidly proliferating astrocytes are exposed to dexamethasone during the first week of secondary culture, most of the astrocytes fail to express any assemblies. The rate of astrocyte proliferation is slowed, and a lower cell density is reached during the first 2 weeks of secondary culture in dexamethasone. The suppression of assemblies is transient: as the cultures approach confluence, the proportion of cells expressing assemblies increases to nearly control levels, and the density of assemblies increases to greater than control values in some astrocytes. Certain of the effects of dexamethasone on cultured astrocytes may have relevance for understanding the mechanism(s) of its action in treating cerebral edema.     

PCR快速鉴定actinobacteria三种模板制备方法的比较

目的 本研究旨在建立准确、简便、快速的放线细菌鉴定技术，为普通和极端环境放线细菌资源的调查和开发利用创造条件。方法 从放线细菌固体培养基上挑取少量菌体，用微波炉法快速制备基因组DNA作为PCR模板，与液体培养法得到的菌体以超声波法或冻融法制备的模板进行了PCR扩增效果的比较研究。结果P CR检测结果表明微波炉法制备的模板可进行有效的体外扩增，目的条带特异，而超声波法或冻融法并不对所有菌株有效，并有非特异扩增产物产生。结论 组合微波炉法快速制备放线细菌基因组DNA技术和23S rRNA特异插入序列PCR扩增技术建立了准确、简便、快速的actinobacteria鉴别体系。     

离体肺冷冻后顺应性的变化

目的:观察家兔离体肺冷冻后顺应性的变化.方法:将32只家兔肺随机均分为对照组、冷冻(0℃)24h组、120h组和240h组.对照组:测定室温条件下的肺顺应性.冷冻组:在相应时间取出冷冻肺,室温条件下复温后,置入生理盐水中,测定注气(或注入生理盐水)和抽气(或抽生理盐水)过程中,肺容积在10ml、20ml、30ml时的顺应性变化.结果:同对照组比较,冷冻24h组向肺内注气10ml,注或抽生理盐水20ml、30ml;冷冻120h组向肺内注气10ml、20ml、30ml,抽气30ml,注生理盐水30ml,抽生理盐水20ml、30ml;冷冻240h组向肺内注生理盐水10ml、20ml、30ml,抽生理盐水20ml、30ml时,差异具有显著性(P＜0.05).其余各组、项与对照组比较差异无显著性(P＞0.05).结论:冷冻不会使肺顺应性发生明显变化,肺顺应性降低与冷冻的时间无明显关系.     

Progress involving new techniques for liposome preparation

The article presents a review of new techniques being used for the preparation of liposomes. A total of 28 publications were examined. In addition to the theories, characteristics and problems associated with traditional methods, the advantages and drawbacks of the latest techniques were reviewed. In the light of developments in many relevant areas, a variety of new techniques are being used for liposome preparation and each of these new technique has particular advantages over conventional preparation methods. However, there are still some problems associated with these new techniques that could hinder their applications and further improvements are needed. Generally speaking, due to the introduction of these latest techniques, liposome preparation is now an improved procedure. These applications promote not only advances in liposome research but also the methods for their production on an industrial scale.     

冷冻联合糠酸莫米松乳膏治疗面部稳定期白癜风疗效研究

目的探讨冷冻联合糠酸莫米松乳膏治疗面部稳定期白癜风的临床疗效及安全性。方法选取我院2016年8月~2019年3月期间皮肤科门诊诊断为白癜风的120例患者作为研究对象,随机分为两组各60例,其中对照组每晚用糠酸莫米松软膏涂搽局部皮损,1次/d,连续用药2周后停药1周,间歇用药,研究组在前者的治疗之前先应用液氮冷冻治疗皮损,间隔3天治疗1次,1周2次,两组疗程均为3个月,对比两组的复色时间及临床疗效。结果研究组总有效率为91.67%明显高于对照组(78.33%),差异有统计学意义(χ~2=4.183,P <0.05)。结论冷冻联合糠酸莫米松乳膏治疗面部稳定期白癜风疗效满意,安全性好,患者易耐受,值得临床推广应用。     

葡萄冻干粉在线粒体应激介导肝细胞凋亡中的作用

目的 了解葡萄冻干粉（FDG）对线粒体应激介导的肝细胞凋亡的阻抑作用,探讨其治疗肝细胞损伤的作用机制。方法用牛磺酸脱氧胆酸（TDCA）诱导Huh7细胞,建立线粒体应激凋亡模型,用不同剂量FDG进行干预。通过MTT、DNA ladder、Western blot、细胞凋亡率检测等方法,了解FDG对Huh7细胞生长、对TDCA诱导的Huh7细胞的凋亡率、凋亡信号蛋白表达的影响。结果FDG（2μg／ml、20μg／ml、200μg／ml、4（10μg／ml和800μg／ml）与Huh7细胞共孵育,FDG可提高Huh7细胞的活力,以FDG400μg／ml时细胞活力最高。用400pMTDCA诱导Huh7细胞,随着诱导时间延长细胞活力下降、凋亡率增加,出现凋亡条带;Caspase-9和7蛋白酶原被活化,PCNA表达下调。用FDG干预TDCA诱导Huh7细胞48h后发现,FDG明显提高Huh7细胞活力、使细胞凋亡减少、凋亡信号蛋白的表达减少。结论TDCA能触发Huh7细胞线粒体氧化应激凋亡,而FDG能促进细胞生长,减轻肝细胞损伤,阻断线粒体氧化应激介导的肝细胞凋亡。     

黄芪冰冻微粉对小鼠耐缺氧和抗疲劳作用的实验研究

目的：探讨黄芪冰冻微粉提高小鼠耐缺氧能力和抗疲劳的作用。方法：采用常压耐缺氧和转棒法观察黄芪冰冻微粉的药效作用。结果：黄芪冰冻微粉可明显延长小鼠在缺氧状态下的存活时间和转棒时间。结论：黄芪冰冻微粉具有明显的抗应激和抗疲劳作用，效果优于普通粉。     

Ultrastructure of guinea pig stria vascularis processed by rapid freezing and freeze substitution

The rapid-freezing and freeze-substitution method fixes a specimen as if it were prepared before excision. We used this method to study the stria vascularis of guinea pigs using electron microscopy. Findings were essentially the same as those obtained with conventional chemical fixation, although freeze substitution made it possible to observe the membrane structures in a smoother and more linear manner. This method seems to be the procedure of choice for studying the instantaneous movement and behavior of cells.     

Renal tubule of dogfish,Scyliorhinus caniculus: A comprehensive study of structure with emphasis on intramembrane particles and immunoreactivity for H+-K+-adenosine triphosphatase

The ultrastructure of renal tubule cells was studied in the European lesser spotted dogfish by the evaluation of thin sections and freeze fracture replicas. Computer-assisted three-dimensional reconstruction of entire nephrons was performed. The distinction of nephron segments and collecting tubule was made using results of previous histological work. The first proximal tubule segment (PI) consists of two subsequent portions, PIa and PIb. PIa is a component of the lateral countercurrent bundle, and PIb, which displays an apical tubulovesicular apparatus and an extended lysosomal compartment, is located in the vicinity of the glomeruli. Rod-shaped intramembrane particles were detected in PIa. The second proximal tubule segment (PII) is a special segment in elasmobranch and teleost fish. PII differs largely from PI in cell morphology and function. The apical cytoplasm was filled with small clear vesicles, and an apical endocytic apparatus was lacking. In the apical cell membrane, rod-shaped particles were revealed by freeze fracture. The apical tight junctions of PI and PII consisted of seven to ten meandering strands. The distal nephron was subdivided into two major segments: early distal tubule (EDT) in the lateral countercurrent bundles and late distal tubule (LDT) in the mesial tissue. The EDT showed marked amplification of basolateral cell membranes. The tight junctions displayed a low number of continuous parallel strands, which is also characteristically found in the diluting segments of other vertebrates. LDT cells showed cytoplasmic studs and rod-shaped intramembraneous particles at the apical cell membrane, thereby resembling type A intercalated cells of collecting duct. The collecting tubule (CT) emerged from the LDT and was part of the countercurrent arrangement inside the lateral bundles. Tight junctions of LDT and CT consisted of many meandering strands in a honeycomb pattern. With immunohistochemistry, binding sites of a polyclonal antibody against an extraplasmic portion of rat gastric H⁺-K⁺-adenosine triphosphatase (ATPase) were observed at the apical cell membrane of PIa, PII, and LDT. From the colocalization of binding sites for the antibody against the transport enzyme with rod-shaped intramembrane particles, we assume that these might be the morphological correlate of gastric H⁺-K⁺-ATPase-like enzyme in the renal tubule. © 1993 Wiley-Liss, Inc.