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排序方式: 共有148条查询结果,搜索用时 15 毫秒
31.
Luana Lugini Cristina Federici Martina Borghi Tommaso Azzarito Maria Lucia Marino Albino Cesolini 《Journal of enzyme inhibition and medicinal chemistry》2016,31(4):538-545
Context: Tumor acidity represents a major cause of chemoresistance. Proton pump inhibitors (PPIs) can neutralize tumor acidity, sensitizing cancer cells to chemotherapy.Objective: To compare the anti-tumor efficacy of different PPIs in vitro and in vivo.Materials and methods: In vitro experiments PPIs anti-tumor efficacy in terms of cell proliferation and cell death/apoptosis/necrosis evaluation were performed. In vivo PPIs efficacy experiments were carried out using melanoma xenograft model in SCID mice.Results: Lansoprazole showed higher anti-tumor effect when compared to the other PPIs. The lansoprazole effect lasted even upon drug removal from the cell culture medium and it was independent from the lipophilicity of the PPIs formulation.Discussion: These PPIs have shown different anti-tumoral efficacy, and the most effective at low dose was lansoprazole.Conclusion: The possibility to contrast tumor acidity by off-label using PPIs opens a new field of oncology investigation. 相似文献
32.
Hamster sarcoma virus (HaSV), a ribonucleic acid tumor virus, pelleted from tissue culture fluid manifests type C morphology by electron microscopy. However, if virus is first concentrated by polyethylene glycol or ammonium sulfate followed by density gradient banding, the virus shows a dramatically atypical barred core structure, termed "theta particles." This structure suggests a condensation of the ribonucleoprotein into a flat disc. Atypical particles are found with HaSV and not in similarly treated feline leukemia virus or Rauscher-murine leukemia virus. Differences in the composition of HaSV as compared with these other viruses may be responsible for the production of such particles. 相似文献
33.
Mutational analysis of the human p53 gene in malignant melanoma 总被引:3,自引:0,他引:3
M Volkenandt U Schlegel D M Nanus A P Albino 《Pigment cell research / sponsored by the European Society for Pigment Cell Research and the International Pigment Cell Society》1991,4(1):35-40
Nine metastatic melanoma cell lines and two melanocyte cell lines were analyzed for point mutations in highly conserved regions of the p53 gene. No mutations were detected in the two melanocytic cell lines and in eight melanoma cell lines. However, a C----T transition at codon 248, resulting in a substitution of tryptophan for arginine, was found in one melanoma cell line. On immunohistochemical staining, only this cell line showed reactivity for mouse monoclonal antibody 1801, which is immunoreactive with human p53 protein. The original paraffin-embedded specimen from which this mutant cell line was established was obtained, and sequence analysis detected the identical mutation in the p53 gene as that seen in the derived cell line. This is the first report indicating point mutations in the p53 gene in malignant melanocytic tissues. 相似文献
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36.
Teresa Catry Jaime Albino Ramos David Monticelli John Bowler Tony Jupiter Matthieu Le Corre 《Journal of Ornithology》2009,150(3):661-669
The White-tailed Tropicbird Phaethon lepturus breeding population of Aride Island, Seychelles, has experienced a strong decline in the recent past. To predict the future
trends of the White-tailed Tropicbird population on Aride Island and understand the urgency of applying management procedures,
we developed a population matrix model. We estimated White-tailed Tropicbird adult survival rate over a 12-year period and
investigated whether oceanographic conditions (El Ni?o Southern Oscillation, ENSO, and inter-annual climate variability in
the Indian Ocean, Indian Ocean Dipole, IOD) or local factors (Pisonia grandis fruiting events) potentially affect adult survival. Annual adult survival could not be linked to inter-annual variability
in oceanographic conditions, but may be more influenced by Pisonia fruiting events, which, overall, accounts for 23.2% of the adult mortality. The growth rate of the population, primarily
influenced by annual adult survival, was estimated to be 0.946, which indicates an annual population decline of 5.4%. At the
current rate, the probability of extinction of this population would be 99% in 170 years. Management scenarios studied through
Monte Carlo simulations, assuming small increments in adult survival and/or breeding success, dramatically reduce the risk
of extinction of White-tailed Tropicbirds. Habitat management, in order to maintain an open canopy and little understorey
vegetation, appears to be crucial for the conservation of White-tailed Tropicbirds on Aride Island, as has already been shown
for other ground-nesting tropical seabirds nesting on forested islands. 相似文献
37.
Anthony P. Albino Ellen D. Jorgensen Patrick Rainey Gene Gillman T. Jeffrey Clark Diana Gietl Hong Zhao Frank Traganos Zbigniew Darzynkiewicz 《Mutation Research - Genetic Toxicology and Environmental Mutagenesis》2009,678(1):43-52
Differentiation among American cigarettes relies primarily on the use of proprietary tobacco blends, menthol, tobacco substitutes, paper porosity, paper additives, and filter ventilation. These characteristics substantially alter per cigarette yields of tar and nicotine in standardized protocols promulgated by government agencies. However, due to compensatory alterations in smoking behavior to sustain a preferred nicotine dose (e.g., by increasing puff frequency, inhaling more deeply, smoking more cigarettes per day, or blocking filter ventilation holes), smokers actually inhale similar amounts of tar and nicotine regardless of any cigarette variable, supporting epidemiological evidence that all brands have comparable disease risk. Consequently, it would be advantageous to develop assays that realistically compare cigarette smoke (CS)-induced genotoxicity regardless of differences in cigarette construction or smoking behavior. One significant indicator of potentially carcinogenic DNA damage is double strand breaks (DSBs), which can be monitored by measuring Ser 139 phosphorylation on histone H2AX. Previously we showed that phosphorylation of H2AX (defined as γH2AX) in exposed lung cells is proportional to CS dose. Thus, we proposed that γH2AX may be a viable biomarker for evaluating genotoxic risk of cigarettes in relation to actual nicotine/tar delivery. Here we tested this hypothesis by measuring γH2AX levels in A549 human lung cells exposed to CS from a range of commercial cigarettes using various smoking regimens. Results show that γH2AX induction, a critical event of the mammalian DNA damage response, provides an assessment of CS-induced DNA damage independent of smoking topography or cigarette type. We conclude that γH2AX induction shows promise as a genotoxic bioassay offering specific advantages over the traditional assays for the evaluation of conventional and nonconventional tobacco products. 相似文献
38.
Sousa A Ferreira IC Calhelha R Andrade PB Valentão P Seabra R Estevinho L Bento A Pereira JA 《Bioorganic & medicinal chemistry》2006,14(24):8533-8538
In the present work, we report the determination of phenolic compounds in ‘alcaparra’ table olives by reversed-phase HPLC/DAD, and the evaluation of their extract in vitro activity against several microorganisms that may be causal agents of human intestinal and respiratory tract infections, namely Gram positive (Bacillus cereus, Bacillus subtilis, and Staphylococcus aureus), Gram negative bacteria (Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae) and fungi (Candida albicans and Cryptococcus neoformans). Three flavonoidic compounds were identified and quantified: luteolin 7-O-glucoside, apigenin 7-O-glucoside, and luteolin. At low concentrations (0.05 mg/mL) ‘alcaparra’ extract revealed significant inhibition of both Gram positive and Gram negative bacteria growth, with exception of P. aeruginosa. Nevertheless, no antifungal activity was observed at the tested concentrations. 相似文献
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40.
Fujita T Maggio A Garcia-Rios M Stauffacher C Bressan RA Csonka LN 《The Journal of biological chemistry》2003,278(16):14203-14210
The first step of proline biosynthesis is catalyzed by gamma-glutamyl kinase (GK). To better understand the feedback inhibition properties of GK, we randomly mutagenized a plasmid carrying tomato tomPRO1 cDNA, which encodes proline-sensitive GK. A pool of mutagenized plasmids was transformed into an Escherichia coli GK mutant, and proline-overproducing derivatives were selected on minimal medium containing the toxic proline analog 3,4-dehydro-dl-proline. Thirty-two mutations that conferred 3,4-dehydro-dl-proline resistance were obtained. Thirteen different single amino acid substitutions were identified at nine different residues. The residues were distributed throughout the N-terminal two-thirds of the polypeptide, but 9 mutations affecting 6 residues were in a cluster of 16 residues. GK assays revealed that these amino acid substitutions caused varying degrees of diminished sensitivity to proline feedback inhibition and also resulted in a range of increased proline accumulation in vivo. GK belongs to a family of amino acid kinases, and a predicted three-dimensional model of this enzyme was constructed on the basis of the crystal structures of three related kinases. In the model, residues that were identified as important for allosteric control were located close to each other, suggesting that they may contribute to the structure of a proline binding site. The putative allosteric binding site partially overlaps the dimerization and substrate binding domains, suggesting that the allosteric regulation of GK may involve a direct structural interaction between the proline binding site and the dimerization and catalytic domains. 相似文献