Environmental Signals Controlling Production of Hemagglutinin/Protease in Vibrio cholerae

Vibrio cholerae hemagglutinin/protease (Hap) was induced upon nutrient limitation and strongly repressed by glucose. Hap was not produced in a mutant defective in the cyclic AMP (cAMP) receptor protein, suggesting that intracellular cAMP levels mediate Hap expression. No difference was found in Hap production between an rpoS deletion mutant and its isogenic wild-type precursor, indicating that the alternate sigma(s) factor is not essential for Hap expression. Based on these and previous results, we discuss the role of Hap in the pathogenesis of cholera.     

Ultrastructural Evidence of Invasive Activity of Vibrio Cholerae

The development of experimental cholera in suckling rabbits is associated with typical cholerogenic syndrome: the presence of Vibrio cholerae in the blood, bile (in 60 and 70% cases, respectively), small and large intestine (in 100% cases). Simultaneously with enterocyte desquamation and increased permeability of the blood-enterocyte barrier, the vibrios are released into villous stroma and then into the microcirculatory bed. the zot toxin is involved in the mechanism of Vibrio cholerae invasion, the corresponding gene is present in the genome of the studied strain.     

Vibrio cholerae Hemagglutinin/Protease Inactivates CTXφ

Pathogenic strains of Vibrio cholerae are lysogens of the filamentous phage CTX, which carries the genes for cholera toxin (ctxAB). We found that the titers of infective CTX in culture supernatants of El Tor CTX lysogens increased rapidly during exponential growth but dropped to undetectable levels late in stationary-phase growth. When CTX transducing particles were mixed with stationary-phase culture supernatants of El Tor strains, CTX infectivity was destroyed. Our data indicate that this growth phase-regulated factor, designated CDF (CTX-destroying factor), is the secreted hemagglutinin/protease (HA/P) of V. cholerae. A strain containing a disrupted hap gene, which encodes HA/P of V. cholerae, did not produce CDF activity in culture supernatants. Introduction of the HA/P-expressing plasmid pCH2 restored CDF activity. Also, CDF activity in culture supernatants of a variety of pathogenic V. cholerae isolates varied widely but correlated with the levels of secreted HA/P, as measured by immunoblotting with anti-HA/P antibody. CDF was purified from V. cholerae culture supernatants and shown to contain a 45-kDa polypeptide which bound anti-HA/P antibodies and which comigrated with HA/P in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The production of high levels of secreted HA/P by certain V. cholerae strains may be a factor in preventing CTX reinfection in natural environments and in the human host.     

Age-Specific Ultrastructural Postradiation Changes in Intestinal Endocrine Cells

Age-specific ultrastructural postradiation changes in the main types of duodenal endocrine cells (apudocytes) were studied in rats 6 and 12 months after single whole-body irradiation in doses of 7 and 7.5 Gy. Ultrastructural disorganization of different severity was detected, which depended on apudocyte type and term postradiation. Degranulation was the basic mechanism of hormone secretion in delayed periods after the exposure.     

细胞松弛素D对稳定层流诱导的VASP改变的作用

探讨细胞松弛素D对稳态层流诱导的actin与VASP分布改变的影响.试验采用人脐静脉内皮细胞(HUVECs)暴露于稳定层流.荧光标记VASP和actin,Western blot检测VASP表达及磷酸化水平.结果表明细胞松弛素D预处理细胞暴露于10 dyn/cm2剪切力1 h后,actin不能沿顺流场方向产生重排,VASP表达减弱;VASP总体表达水平不仅无增加,且无磷酸化VASP出现.以上提示VASP通过反复磷酸/脱磷酸化介导剪切力引起的细胞骨架重排,进而细胞形态改变,这种调节作用的发挥有赖于细胞骨架的完整.     

Ultrastructural Changes in Cells of the Mouse Footpad Infected with Mycobacterium leprae

Ultrastructural changes in cells of the mouse footpad are described which occurred during the log phase of multiplication, the plateau, and the stationary phase of growth of Mycobacterium leprae.BALB/c mice were inoculated in the right hind footpad with 5 x 10(3) organisms and sacrificed in pairs at 86 to 173 days after inoculation. Tissue samples were prepared for electron microscopy by standard techniques. During the early growth phase of M. leprae in the mouse footpad, few organisms can be detected. Those present are in macrophages and are bound by a single membrane. The cytoplasm of the macrophage is less dense around the organism. There are few lysosomes, and the bacteria do not appear to be degenerating. At the peak of the growth phase, the organisms within a macrophage are bound by either a single or double membrane. There is an increased number of vacuoles, which are also bound by a double membrane, and lysosomes. During the stationary phase, most of the macrophages have taken on a vacuolar appearance and contain lysosomes. The vacuoles are bound by a double membrane, as are most of the organisms within the macrophage. Many of these organisms appear to be degenerating. Occasionally, organisms are encountered in the sarcoplasm of striated muscle. They are usually bound by a single membrane and do not appear to be degenerating.     

缺氧与复氧对培养的肺动脉内皮细胞功能的影响

缺氧与复氧均可引起肺血管收缩和损伤，本研究观察肺血管内皮细胞活力和血管紧张素转换酶（ＡＣＥ）释放在其中的作用。培养的新生小牛肺动脉内皮细胞（ＰＡＥＣ）在缺氧条件下（０％Ｏ２－９５％Ｎ２）培养６～２４ｈ，其上清液ＡＣＥ活性无显著变化，而细胞活力于缺氧１２～２４ｈ显著增加（与常氧组相比增加２０％～３３％，Ｐ＜０．０５）。ＰＡＥＣ在缺氧条件下培养２４ｈ，复氧培养３～６ｈ后其上清液ＡＣＥ活性显著增加（与常氧组和缺氧组相比Ｐ＜０．０１），于１２ｈ恢复至复氧前的水平。细胞活力的变化与ＡＣＥ的变化类似，复氧３～６ｈ显著高于常氧水平（Ｐ＜０．０１与常氧组相比），１２ｈ恢复至正常。上述结果表明ＰＡＥＣ的ＡＣＥ和细胞活力的变化可能对肺动脉壁本身ＲＡＳ功能的调节及缺氧性肺血管收缩的发生起一定作用。     

Ultrastructural Changes in Prostate Cells During Hormone-induced Canine Prostatic Hyperplasia

Benign prostatic hyperplasia is a prevalent disease that has received relatively little attention in spite of its morbidity and remarkable social impact. There are few animal models of prostatic hyperplasia. The dog is the only species, along with humans, in which prostatic hyperplasia develops spontaneously and almost universally with age. The aim of the present study has been to compare the ultrastructural findings in a model of experimentally induced canine prostatic hyperplasia with those of the spontaneously developed changes in untreated dogs. An experimental group of 5 male beagle dogs were castrated and treated with combined steroids (3 weekly doses for over 30 weeks). Prostate samples were surgically obtained every 42 days (experimental stages 0 through 6). The control group consisted of 3 noncastrated dogs that were treated with vehicle and in which samples were taken only at stages 0, 1, 4, and 6. Changes in the control groups were similar but of lower intensity compared to those of the experimental groups. In luminal cells, crowding with papillary projections, prominent, branching microvilli, and abundant, often compartmentalized granules were observed. The most striking change was the previously unreported finding of caveolae in basal cells. They were mostly located in the basal aspect of basal cells and were more prominent in the experimental group and in advanced stages of treatment. These ultrastructural findings have not been previously reported in canine or human prostatic hyperplasia and merit further research. The model of experimentally induced canine prostatic hyperplasia provides an adequate setting for the understanding of this disease.     

Ultrastructural Studies of Glioma Stem Cells/Progenitor Cells

Although the ultrastructural features of several brain tumor cells have been studied in details, the ultrastructure of glioma stem cells/progenitors cells (GSPC) has rarely been reported. In this paper, the authors describe the ultrastructural features of GSPCs isolated from both a glioma tissue and the human glioma cell SHG-44 cell line. The ultrastructural features of the two kinds of GSPCs were similar, with relatively developed mitochondria, Golgi apparatuses, ribosomes, undeveloped rough endoplasmic reticula, seldom lysosomes and no typical autophagosomes, and high nuclear–cytoplasmic ratio. Their nuclei, frequently containing huge amounts of euchromatin and a small quantity of heterochromatin, were mostly globular; and the majority of the nuclei had only one nucleole. Typical apoptotic cells could hardly be found in tumor spheres, and between adjacent cells there were cell junctions, which probably were incompletely developed desmosomes or intermediate junctions. In conclusion, their ultrastructural features showed that GSPCs were at the primary stage of differentiation, and could even partially reveal the underlying reasons for the malignant proliferation and differential inhibition of GSPCs.     

Surface Topography and Ultrastructural Changes of Mucinous Carcinoma Breast Cells

Mucinous carcinoma of the breast (MCB) is histologically classified into 2 groups: (1) pure MCB and (2) mixed MCB. Pure MCB carries a better diagnosis than mixed MCB. This research relates to the cell surface topography and ultrastructure of the cells in the above cases and aims to find the differences between them, by means of two methods: scanning electron microscopy (SEM) and transmission electron microscopy (TEM). For the SEM examination, it was necessary to initially culture the MCB tissues and then proceed with the usual SEM method. In contrast, for the TEM technique, MCB tissues were initially fixed followed by the classic TEM method. The authors found the topography of pure MCB cases to be without nodes. The cell membrane was smooth, with numerous pores and small ruffles that covered the entire cell. The ultrastructural appearance of the same cases was with a normal cell membrane containing abundant collagen fibers. They also had many small vesicles containing mucin as well as secretory droplets. In contrast the mixed MCB had a number of lymph nodes and their cell surface topography showed stronger changes such as microvilli, numerous blebs, ruffles and many long projections. Their ultrastructure showed very long microvilli with large cytoplasmic inclusions and extracellular mucin collections, electron-dense material vacuoles, and many important cytoplasmic organelles. An important fact is that mixed MCB also contains areas of infiltrating ductal carcinoma. These cells of the cytoplasmic organelles are clearly responsible for the synthesis, storage, and secretion of the characteristic mucin of this tumor type. Evidently, this abnormal mucin production and the abundance of secretory granules along with the long projections observed in the topographical structure might be responsible for transferring tumor cells to neighboring organs, thus being responsible for metastatic disease.     

Ultrastructural Changes in Cells of the Gastric and Small Intestinal Mucosa during Bronchial Asthma

The complex of structural changes in the gastroduodenal mucosa in patients with bronchial asthma is considered as a polyetiological primary degenerative process with progressive atrophy of the epithelium and formation of erosions. Ultrastructural signs included degenerative changes in the endothelium of microvessels and surface and glandular epithelium, which were accompanied by compensatory hyperfunction of intact mucus-producing cells, hyperplasia, and increased functional activity of mast and immunocompetent cells. The development of destructive and erosive lesions was associated with hyperplasia of parietal and endocrine cells in the mucosa. We evaluated the specific structural reactions clinically typical of bronchial asthma of different severity. The data are interpreted in terms of a relationship between pathological changes in the mucosa of different localization.     

抗霍乱弧菌O139群单克隆抗体的制备及初步鉴定

制备抗霍乱弧菌(V. cholerae)O139群特异性单克隆抗体(MAbs),进而制备检测霍乱弧菌O139群的胶体金免疫层析试纸条.福尔马林灭活的霍乱弧菌O139群免疫BALB/c小鼠,应用细胞融合技术建立分泌抗霍乱弧菌O139群MAbs的杂交瘤细胞株.对配对较好的4株MAbs用ELISA法测定MAbs免疫球蛋白类及亚类,用ELISA法和凝集法鉴定MAbs的特异性.结果表明4株MAbs免疫球蛋白均为小鼠IgM;这些MAbs均与霍乱弧菌O139群菌株发生凝集反应,与霍乱弧菌O1群、大肠杆菌、出血性大肠杆菌O157∶H7、副溶血弧菌、麦氏弧菌、河弧菌、结肠炎耶尔森氏菌、普通变形杆菌、痢疾杆菌、伤寒杆菌及甲型、乙型、丙型副伤寒杆菌不发生凝集反应.4株MAbs具有较高的特异性,有可能用于制备检测霍乱弧菌O139群的检测试剂.     

表阿霉素诱导血管通透性改变的机制

目的:观察乳腺癌常规化疗药物表阿霉素(EPI)对血管内皮细胞通透性的影响,探讨其在静脉注射时造成血管渗漏的机制。方法:用0、0.1、1.0、10、100μg/mlEPI处理人脐静脉内皮细胞株HUVEC-CRL-1730,光学显微镜观察细胞形态改变,Transwell小室检测单层内皮细胞的通透性,MTT法检测细胞增殖效率,RT-PCR和Western blotting检测血管扩张刺激磷蛋白(VASP)mRNA和蛋白表达水平。结果:10μg/mlEPI处理内皮细胞24h后,与对照组相比,EPI能显著抑制内皮细胞增殖(P<0.05),细胞收缩、变形,单层内皮细胞通透性增加(P<0.05);同时,VASP mRNA和蛋白表达水平均降低(P<0.05)。结论:EPI静脉注射造成的血管渗漏可能与EPI抑制细胞增殖以及通过降低VASP蛋白表达导致的内皮细胞通透性增加有关。     

黄芪甙对霍乱弧菌LPS体外诱生TNF的影响

本文应用黄芪甙ＡＳＩ或ＳＫ和霍乱弧菌ＬＰＳ刺激小鼠腹腔巨噬细胞诱生ＴＮＦ，用适当浓度（１～１０μｇ／ｍｌ）ＡＳＩ或ＳＫ和ＬＰＳ刺激巨噬细胞（Ｍφ）比单用霍乱弧菌ＬＰＳ诱生ＴＮＦ量约增加４～５倍。证实黄芪甙有促进ＬＰＳ诱生ＴＮＦ的作用。应用霍乱弧菌不同菌株提取ＬＰＳ，右典生物型５６９Ｂ菌株诱生ＴＮＦ活性高于ＥＩＴｏｒ生物型Ｗｊ２菌株，证实前者ＬＰＳ活性比后者强。     

Ultrastructural Changes in Smooth Muscle Cells of the Small Intestine in Suckling Rabbits with Experimental Cholera

Ultrastructural study of the small intestine in suckling rabbits with experimental cholera revealed involvement of the inner and outer smooth muscle layers into the pathological process. Smooth muscle cells were characterized by vacuolar and fatty degeneration and focal colliquative necrosis. Apoptosis played little role in gastrointestinal motility disturbances. The presence of considerable amounts of fluid in intestinal loops reflects peristaltic dysfunction due to generalized damage to smooth muscle cells.     

Effect of Recombinant Erythropoietin on Functional Activity of Cultured Human Cells

We studied the effect of recombinant human erythropoietin on functional activity of skin cells in vitro. It was found that erythropoietin stimulated proliferation of mesenchymal and epithelial cells and effectively protected epidermal HaCaT cells from apoptosis. Insignificant effect of erythropoietin on contraction of collagen gel by mesenchymal cells was revealed. These findings suggest that erythropoietin can be a promising component of wound-healing preparations.     

Ultrastructural Changes Associated with Peripheral Neuropathy in HIV/AIDS

Light and electron microscopic studies were performed on neuromuscular biopsy specimens from 12 neurologically affected seropositive patients, 7 with the acquired immune deficiency syndrome (AIDS), 2 with AIDS-related complex, and 3 with no symptoms except for neuropathy. All patients had an axonal injury associated or unassociated with demyelination and peripheral neurogenic atrophy. Capillary lesions were consistently present, which seems to be a new finding. Moreover, tubuloreticular inclusions (TRIs) were found in endomysial (9 of 12 cases) and endoneurial (7 of 12 cases) vessels. Statistical analysis showed that TRIs in more than 20% of endomysial vessels correlated with a survival time shorter than 12 months (P = 0.028). Thus the quantification of TRIs seems to be one of the vital prognostic elements in this patient population.     

Effect of Group A Streptococcal Cysteine Protease on Invasion of Epithelial Cells

Cysteine protease of group A streptococci (GAS) is considered an important virulence factor. However, its role in invasiveness of GAS has not been investigated. We demonstrated in this study that two strains of protease-producing GAS had the ability to invade A-549 human respiratory epithelial cells. Isogenic protease mutants were constructed by using integrational plasmids to disrupt the speB gene and confirmed by Southern hybridization and Western immunoblot analyses. No extracellular protease activity was produced by the mutants. The mutants had growth rates similar to those of the wild-type strains and produced normal levels of other extracellular proteins. When invading A-549 cells, the mutants had a two- to threefold decrease in activity compared to that of the wild-type strains. The invasion activity increased when the A-549 cells were incubated with purified cysteine protease and the mutant. However, blockage of the cysteine protease with a specific cysteine protease inhibitor, E-64, decreased the invasion activity of GAS. Intracellular growth of GAS was not found in A-549 cells. The presence or absence of protease activity did not affect the adhesive ability of GAS. These results suggested that streptococcal cysteine protease can enhance the invasion ability of GAS in human respiratory epithelial cells.