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991.
Maiques JM Doménech A Cabellos C Fernández A Ribes S Tubau F Gudiol F Viladrich PF 《Microbes and infection / Institut Pasteur》2007,9(4):435-441
To compare the efficacy of meropenem, ceftazidime, tobramycin and ceftazidime+tobramycin in a guinea-pig model of P. aeruginosa meningitis. After anesthesia, the atlanto-occipital membrane was punctured with a butterfly needle and 100 microl of a solution containing 10(6)CFU/ml of P. aeruginosa were injected directly into the cisterna magna. Four h later, therapy was initiated with saline or antibiotics given im for 48 h in doses that obtained CSF levels as in human meningitis: ceftazidime 200 mg/kg/8h, meropenem 200 mg/kg/8h, tobramycin 30 mg/kg/24h. Tobramycin was also given intracisternally. Animals were sacrificed at different time points. CSF and blood samples were collected and a meningeal swab was performed. Four hours after inoculation, bacterial concentration in CSF was 4 to 5log10CFU and mean WBC was 16,000/-l. All control animals died in 24h with a 12% increase in cerebral edema. All blood-cultures were negative. Ceftazidime, ceftazidime+tobramycin and meropenem reduced the CSF bacterial concentration at 8h by 2.5log10. At 48 h all CSF cultures were sterile but meningeal swab cultures remained positive in 30%. Our results suggest that meropenem may be at least as effective as ceftazidime and that the addition of tobramycin to ceftazidime may improve its efficacy. 相似文献
992.
993.
Overexpression, purification and characterization of the Trichoderma atroviride endochitinase, Ech42, in Pichia pastoris 总被引:1,自引:0,他引:1
Pérez-Martínez AS De León-Rodríguez A Harris LJ Herrera-Estrella A Barba de la Rosa AP 《Protein expression and purification》2007,55(1):183-188
The endochitinase gene ech42 from Trichoderma atroviride was cloned and expressed in Pichia pastoris using a constitutive expression system. Over 98% of the recombinant protein was secreted into the culture medium as glycoprotein. A high endochitinase concentration, 186 mg/L with a specific enzyme activity of 14,128 Umg(-1) was produced. The optimal enzyme kinetic parameters for the recombinant protein were identical to those reported for the enzyme isolated from T. atroviride. The recombinant endochitinase possesses suitable features for biotechnological applications, such as activity at acidic pH and thermostability. 相似文献
994.
995.
996.
Ochoa JJ Contreras-Chova F Muñoz S Araujo-Nepomuceno E Bonillo A Molina-Carballo A Muñoz-Hoyos A 《Free radical research》2007,41(9):1035-1040
Objective: To study the evolution of lipid peroxidation, enzymatic antioxidants response, lipid profile and membrane fluidity in erythrocytes from very low birth weight (VLBW) infants during their first 7 days of extra-uterine life.
Study design: One hundred and twenty infants were selected and divided in two groups according to their weight and gestational age. Hydroperoxides, fatty-acid profile, fluidity (DPH and TMA-DPH) and catalase, SOD and GPx activities were measured in erythrocytes.
Results: VLBW group showed higher concentration of hydroperoxides and lower membrane fluidity during the first 72 h, lower SOD activity during the first 3 h and higher GPx activity during the first 7 days of life. Also, this group showed lower n-3 polyunsaturated fatty-acids percentage with respect to the term group.
Conclusion: Erythrocytes from VLBW infants showed higher oxidative damage and lower fluidity in their membranes, at least during the first 3 days of extra-uterine life, which may cause alterations in their functions and flexibility. 相似文献
Study design: One hundred and twenty infants were selected and divided in two groups according to their weight and gestational age. Hydroperoxides, fatty-acid profile, fluidity (DPH and TMA-DPH) and catalase, SOD and GPx activities were measured in erythrocytes.
Results: VLBW group showed higher concentration of hydroperoxides and lower membrane fluidity during the first 72 h, lower SOD activity during the first 3 h and higher GPx activity during the first 7 days of life. Also, this group showed lower n-3 polyunsaturated fatty-acids percentage with respect to the term group.
Conclusion: Erythrocytes from VLBW infants showed higher oxidative damage and lower fluidity in their membranes, at least during the first 3 days of extra-uterine life, which may cause alterations in their functions and flexibility. 相似文献
997.
López-Sánchez LM Collado JA Corrales FJ López-Cillero P Montero JL Fraga E Serrano J De La Mata M Muntané J Rodríguez-Ariza A 《Free radical research》2007,41(1):50-61
Nitric oxide (NO) participates in the cell death induced by d-Galactosamine (d-GalN) in hepatocytes, and NO-derived reactive oxygen intermediates are critical contributors to protein modification and hepatocellular injury. It is anticipated that S-nitrosation of proteins will participate in the mechanisms leading to cell death in d-GalN-treated human hepatocytes. In the present study, d-GalN-induced cell death was related to augmented levels of NO production and S-nitrosothiol (SNO) content. The biotin switch assay confirmed that d-GalN increased the levels of S-nitrosated proteins in human hepatocytes. S-nitrosocysteine (CSNO) enhanced protein S-nitrosation and altered cell death parameters that were related to S-nitrosation of the executioner caspase-3. Fifteen S-nitrosated proteins participating in metabolism, antioxidative defense and cellular homeostasis were identified in human hepatocytes treated with CSNO. Among them, seven were also identified in d-GalN-treated hepatocytes. The results here reported underline the importance of the alteration of SNO homeostasis during d-GalN-induced cell death in human hepatocytes. 相似文献
998.
Vitale I Antoccia A Cenciarelli C Crateri P Meschini S Arancia G Pisano C Tanzarella C 《Apoptosis : an international journal on programmed cell death》2007,12(1):155-166
Combretastatin A-4 (CA-4), a natural stilbenoid isolated from Combretum caffrum, is a new vascular targeting agent (VTA) known for its antitumor activity due to its anti-tubulin properties. We investigated
the molecular mechanisms leading to cell death in non-small cell lung cancer H460 cells induced by natural (CA-4) and synthetic
stilbenoids (ST2151) structurally related to CA-4. We found that both compounds induced depolymerization and rearrangement
of spindle microtubules, as well as an increasingly aberrant organization of metaphase chromosomes in a dose- and time-dependent
manner. Prolonged exposition to ST2151 led cells to organize multiple sites of tubulin repolymerization, whereas tubulin repolymerization
was observed only after CA-4 washout. H460 cells were arrested at a pro-metaphase stage, with condensed chromosomes and a
triggered spindle assembly checkpoint, as evaluated by kinetochore localization of Bub1 and Mad1 antibodies. Persistent checkpoint
activation led to mitochondrial membrane permeabilization (MMP) alterations, cytochrome c release, activation of caspase-9 and -3, PARP cleavage and DNA fragmentation. On the other hand, caspase-2, and -8 were not
activated by the drug treatment. The ability of cells to reassemble tubulin in the presence of an activated checkpoint may
be responsible for ST2151-induced multinucleation, a recognized sign of mitotic catastrophe. In conclusion, we believe that
discovery of new agents able to trigger mitotic catastrophe cell death as a result of mitotic block and prolonged spindle
checkpoint activation is particularly worthwhile, considering that tumor cells have a high proliferative rate and mitotic
failure occurs irrespective of p53 status.
Electronic Supplementary Material Supplementary material is available in the online version of this article at .
Ilio Vitale and Antonio Antoccia contribuited equally to this work. 相似文献
999.
Marie-Pierre Ledru Maria Luisa Ferraz Salatino Gregorio Ceccantini Antonio Salatino Fabio Pinheiro Jean-Christophe Pintaud 《Diversity & distributions》2007,13(6):761-771
For decades, palynologists working in tropical South America are using the genus Podocarpus as a climate indicator although without referring to any modern data concerning its distribution and limiting factors. With the aim to characterize the modern and past distribution of the southern conifer Podocarpus in Brazil and to obtain new information on the distribution of the Atlantic rainforest during the Quaternary, we examined herbarium data to locate the populations of three Brazilian endemic Podocarpus species: P. sellowii, P. lambertii , and P. brasiliensis , and extracted DNA from fresh leaves from 26 populations. Our conclusions are drawn in the light of the combination of these three disciplines: botany, palynology, and genetics. We find that the modern distribution of endemic Podocarpus populations shows that they are widely dispersed in eastern Brazil, from north to south and reveals that the expansion of Podocarpus recorded in single Amazonian pollen records may have come from either western or eastern populations. Genetic analysis enabled us to delimit regional expansion: between 5° and 15° S grouping northern and central populations of P. sellowii expanded c . 16,000 years ago; between 15° and 23° S populations of either P. lambertii or sellowii expanded at different times since at least the last glaciation; and between 23° and 30° S, P. lambertii appeared during the recent expansion of the Araucaria forest. The combination of botany, pollen, and molecular analysis proved to be a rapid tool for inferring distribution borders for sparse populations and their regional evolution within tropical ecosystems. Today the refugia of rainforest communities we identified are crucial hotspots to allow the Atlantic forest to survive under unfavourable climatic conditions and, as such, offer the only possible opportunity for this type of forest to expand in the event of a future climate change. 相似文献
1000.