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1.
M Corr A von Damm D J Lee H Tighe 《Journal of immunology (Baltimore, Md. : 1950)》1999,163(9):4721-4727
DNA vaccines can stimulate both humoral and cytolytic immune responses. Although bone marrow-derived elements present the expressed Ag, the mechanisms for acquiring immunogenic peptides have yet to be fully elucidated. APCs may become directly transfected by plasmid DNA or process extracellular proteins produced by other transfected cells. Using a transactivating plasmid system and bone marrow chimeras, we show that both mechanisms appear to be involved; however, the bulk of the immune response is dependent on expression of Ag by nonlymphoid tissues and transfer to APCs. These in vivo studies are the first to define the role of transfected nonlymphoid cells in generating Ag for presentation by bone marrow-derived APCs after needle injection with plasmid DNA. 相似文献
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A Pierré M Robert-Géro C Tempête J Polonsky 《Biochemical and biophysical research communications》1980,93(3):675-686
The effects of eleven quassinoids on Rous sarcoma virus induced cell transformation and on growth of normal cells were examined. At concentrations of 0.15-1 μg/ml they inhibited foci formation (76–99 %) without toxic effects on normal cells. The most active compounds also affected virus production by transformed cells. In intact normal and transformed cells, protein and DNA synthesis was equally affected after 3 hours of exposure to quassinoids of both cell types. RNA synthesis was not inhibited. This study has shown that the structural requirement of a C-15 ester in the quassinoids for antileukemic activity and is not essential for their antitransforming activity. 相似文献
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Toxin gamma is a basic, low-molecular-weight, neurotoxic protein, isolated from the venom of the Brazilian scorpion, Tityus serrulatus. Raman spectra (400-1800 cm-1 region) of this toxin in both the lyophilized state and in 0.1 M acetate buffer (pH 4.5) and the infrared spectrum (700-4000 cm-1 region) of a solid film were investigated. From the vibrational spectra, it can be concluded that the polypeptide backbone of toxin gamma consists of a mixture of the different secondary structures, with predominance of beta-sheet, followed by unordered structure and alpha-helix, with some evidence of beta-turn structures. The four disulfide bridges assume the gauche-gauche-gauche conformation of the CCSSCC fragments. The intensity ratio of the doublet at 853 and 828 cm-1 suggests that four out of the five tyrosine residues are exposed. The three tryptophan residues are exposed on the surface, and the single methionine residue assume the gauche-gauche conformation. Toxin gamma retains full activity in the pH 4.5-7.5 range, but is almost completely inactivated at pH 11.5. 相似文献
5.
Gustavo de Rezende Corrêa Karinne Cristinne da Silva Cunha Aline Araujo dos Santos Elizabeth Giestal de Araujo 《Neurochemical research》2010,35(9):1343-1352
It was already shown that ouabain treatment can stimulate PKC isoenzymes leading to the activation of intracellular pathways
involved in cell survival, growth and proliferation. We have previously demonstrated that ouabain or PMA treatment increases
retinal ganglion cell survival, an effect mediated by PKC activation. The aim of this work was to investigate the role of
EGF receptors in the ouabain effect and also to study which PKC isoform is activated by treatment with ouabain and PMA. Our
results show that 2.5 μM tyrphostin, 1.0 μM PP1, 4.0 μM U73122, 1.0 μM JNK inhibitor V and 2.0 μM rottlerin blocked the ouabain
effect indicating an involvement of receptors for EGF, Src, PLC, JNK and PKC δ respectively. The effect of PMA was only abolished
when cultures were treated with rottlerin or with the JNK inhibitor suggesting the involvement of PKC δ and JNK. These results
indicate that PKC δ could be a key regulator of retinal ganglion cell survival. 相似文献
6.
Carolina V. Messias Eliane Santana-Van-Vliet Julia P. Lemos Otacilio C. Moreira Vinicius Cotta-de-Almeida Wilson Savino Daniella Arêas Mendes-da-Cruz 《PloS one》2016,11(1)
Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid involved in several physiological processes including cell migration and differentiation. S1P signaling is mediated through five G protein-coupled receptors (S1P1-S1P5). S1P1 is crucial to the exit of T-lymphocytes from the thymus and peripheral lymphoid organs through a gradient of S1P. We have previously observed that T-ALL and T-LBL blasts express S1P1. Herein we analyzed the role of S1P receptors in the migratory pattern of human T-cell neoplastic blasts. S1P-triggered cell migration was directly related to S1P1 expression. T-ALL blasts expressing low levels of S1P1 mRNA (HPB-ALL) did not migrate toward S1P, whereas those expressing higher levels of S1P1 (MOLT-4, JURKAT and CEM) did migrate. The S1P ligand induced T-ALL cells chemotaxis in concentrations up to 500 nM and induced fugetaxis in higher concentrations (1000–10000 nM) through interactions with S1P1. When S1P1 was specifically blocked by the W146 compound, S1P-induced migration at lower concentrations was reduced, whereas higher concentrations induced cell migration. Furthermore, we observed that S1P/S1P1 interactions induced ERK and AKT phosphorylation, and modulation of Rac1 activity. Responding T-ALL blasts also expressed S1P3 mRNA but blockage of this receptor did not modify migratory responses. Our results indicate that S1P is involved in the migration of T-ALL/LBL blasts, which is dependent on S1P1 expression. Moreover, S1P concentrations in the given microenvironment might induce dose-dependent chemotaxis or fugetaxis of T-ALL blasts. 相似文献
7.
Sacramento Doralice Rodrigues Coelho Rosalie Reed Rodrigues Wigg Márcia Dutra Toledo Luna Linhares Luiz Fernando de Matos dos Santos Marta Gonçalves Azevedo Soares Semêdo Luzia Teixeira de Ribeiro da Silva Antonio Jorge 《World journal of microbiology & biotechnology》2004,20(3):225-229
A promising producer of bioactive compounds isolated from a Brazilian tropical soil was tested for its range of antimicrobial
activities. Strain 606, classified as Streptomyces sp., could not be identified up to species level, suggesting a possible new taxon. The supernatant and 10 extracts and fractions,
obtained by extraction and chromatographic techniques, presented antimicrobial activity using antibiograms. The methanolic
fraction was highly active against pathogenic bacteria, phytopathogenic fungi and the human pathogenic yeast Candida albicans. It also possessed high antiviral activity inhibiting the propagation of an acyclovir-resistant herpes simplex virus type
1 strain on HEp-2 cells at non-cytotoxic concentration. The strong cytotoxic effect suggests an antitumour action.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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L. Corr 《BMJ (Clinical research ed.)》1994,309(6954):579-583
The use of percutaneous transluminal coronary angioplasty is limited by procedural complications and the serious drawback of restenosis, but some new techniques have been developed in an attempt to lower the complication rate for difficult lesions and reduce the rate of restenosis. These include devices to physically remove atheromatous plaque, such as the Simpson Coronary AtheroCath and the transluminal extraction catheter, as well as devices to ablate the plaque in situ, including the Rotablator and the excimer laser catheter. Although each device may have advantages in certain types of lesion, few data on their use have been reported in properly controlled randomised trials. The data available so far do not suggest that these devices will be safer than balloon angioplasty or that they will reduce restenosis. However, using metallic stents to support coronary arteries after balloon angioplasty seems to reduce acute complications and to lower the rate of restenosis, and the use of stents is likely to increase. 相似文献