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81.
Fernández V Tapia G Varela P Gaete L Vera G Mora C Vial MT Videla LA 《Free radical biology & medicine》2008,44(9):1724-1731
Hepatic ischemia-reperfusion (IR) injury, a major clinical drawback during surgery, is abolished by L-3,3',5-triiodothyronine (T(3)) administration. Considering that the triggering mechanisms are unknown, the aim of this study is to assess the role of oxidative stress in T(3) preconditioning using N-acetylcysteine (NAC) before T(3) administration. Male Sprague-Dawley rats given a single dose of 0.1 mg of T(3)/kg were subjected to 1 h ischemia followed by 20 h reperfusion, in groups of animals pretreated with 0.5 g of NAC/kg 0.5 h before T(3) or with the respective control vehicles. At the end of the reperfusion period, blood and liver samples were taken for analysis of serum aspartate aminotransferase (AST) and hepatic histology, glutathione (GSH) and protein carbonyl contents, and nuclear factor-kappaB (NF-kappaB) and activating protein 1 (AP-1) DNA binding. The IR protocol used led to a 4.5-fold increase in serum AST levels and drastic changes in liver histology, with significant GSH depletion and enhancement of protein carbonyl levels and of the protein carbonyl/GSH content ratio, whereas NF-kappaB and AP-1 DNA binding was decreased and enhanced, respectively. In a time window of 48 h, T(3) exerted protection against hepatic IR injury, with 88% reduction in the protein carbonyl/GSH ratio and normalization of NF-kappaB and AP-1 DNA binding, changes that were suppressed by NAC administration before T(3). Data presented suggest that a transient increase in the oxidative stress status of the liver is an important trigger for T(3) preconditioning, evidenced in a warm IR injury model through antioxidant intervention. 相似文献
82.
Leonardo P. Farias Greice Krautz-Peterson Cibele A. Tararam Bogar O. Araujo-Montoya Tatiana R. Fraga Henrique K. Rofatto Floriano P. Silva-Jr Lourdes Isaac Akram A. Da'dara R. Alan Wilson Charles B. Shoemaker Luciana C. C. Leite 《PLoS neglected tropical diseases》2013,7(10)
Background
It is believed that schistosomes evade complement-mediated killing by expressing regulatory proteins on their surface. Recently, six homologues of human CD59, an important inhibitor of the complement system membrane attack complex, were identified in the schistosome genome. Therefore, it is important to investigate whether these molecules could act as CD59-like complement inhibitors in schistosomes as part of an immune evasion strategy.Methodology/Principal Findings
Herein, we describe the molecular characterization of seven putative SmCD59-like genes and attempt to address the putative biological function of two isoforms. Superimposition analysis of the 3D structure of hCD59 and schistosome sequences revealed that they contain the three-fingered protein domain (TFPD). However, the conserved amino acid residues involved in complement recognition in mammals could not be identified. Real-time RT-PCR and Western blot analysis determined that most of these genes are up-regulated in the transition from free-living cercaria to adult worm stage. Immunolocalization experiments and tegument preparations confirm that at least some of the SmCD59-like proteins are surface-localized; however, significant expression was also detected in internal tissues of adult worms. Finally, the involvement of two SmCD59 proteins in complement inhibition was evaluated by three different approaches: (i) a hemolytic assay using recombinant soluble forms expressed in Pichia pastoris and E. coli; (ii) complement-resistance of CHO cells expressing the respective membrane-anchored proteins; and (iii) the complement killing of schistosomula after gene suppression by RNAi. Our data indicated that these proteins are not involved in the regulation of complement activation.Conclusions
Our results suggest that this group of proteins belongs to the TFPD superfamily. Their expression is associated to intra-host stages, present in the tegument surface, and also in intra-parasite tissues. Three distinct approaches using SmCD59 proteins to inhibit complement strongly suggested that these proteins are not complement inhibitors and their function in schistosomes remains to be determined. 相似文献83.
Cristie Grazziotin Noschang Rachel Krolow Leticia Ferreira Pettenuzzo Mônica Colpini Ávila Andrelisa Fachin Danusa Arcego Eduardo von Pozzer Toigo Leonardo Machado Crema Luísa Amália Diehl Deusa Vendite Carla Dalmaz 《Neurochemical research》2009,34(9):1568-1574
We studied the effect of chronic caffeine on parameters related to oxidative stress in different brain regions of stressed
and non-stressed rats. Wistar rats were divided into three groups: control (receiving water), caffeine 0.3 g/L and caffeine
1.0 g/L (in the drinking water). These groups were subdivided into non-stressed and stressed (repeated restraint stress during
40 days). Lipid peroxide levels and the total radical-trapping potential were assessed, as well as antioxidant enzyme activities
superoxide dismutase, gluthatione peroxidase, and catalase in hippocampus, striatum and cerebral cortex. Results showed interactions
between stress and caffeine, especially in the cerebral cortex, since caffeine increased the activity of some antioxidant
enzymes, but not in stressed animals. We concluded that chronic administration of caffeine led, in some cases, to increased
activity of antioxidant enzymes. However, these effects were not observed in the stressed animals. 相似文献
84.
Hydroxyl Radicals and a Thylakoid-Bound Endopeptidase are Involved in Light- and Oxygen-Induced Proteolysis in Oat Chloroplasts 总被引:4,自引:0,他引:4
Casano Leonardo M.; Lascano H. Ramiro; Trippi Victorio S. 《Plant & cell physiology》1994,35(2):145-152
The hypothesis that light- and oxygen-induced proteolysis inchloroplasts is mediated by active oxygen species was examined.In order to determine whether or not H2O2 and/or {dot}OH radicalsare involved in these degradative processes we compared thedegradation of proteins in isolated oat chloroplasts exposedto white light at 80 W m-2 with that in chloroplasts incubatedin darkness in the absence or presence of H2O2 or a {dot}OH-generatingsystem composed by ascorbic acid, FeCl3 and H2O2 (Asc-Fe-H2O2).Light enhanced the rate of degradation of at least 18 polypeptides,while proteolysis was almost negligible in darkness in the abscenceof additives. H2O2 had a very small effect. However, Asc-Fe-H2O2-treatedchloroplasts in darkness showed a pattern of protein degradationalmost identical to that observed in the light. A thylakoid-boundendopeptidase (EP), the activity of which increased under photooxidativeenvironmental conditions and treatment with an {dot}OH-generatingsystem, was partially purified and characterized as a serinetypeprotease. Treatments with inhibitors of serine-type proteaseprevented both light- and Asc- Fe-H2O2-induced proteolysis.EP was more active against both soluble and membranous proteinsthat had been pretreated with Asc-Fe-H2O2 than against untreatedproteins. It is proposed that a high dose of light irradiationpromotes proteolysis by increasing the formation of {dot}OH,which may modify proteins such that they become more susceptibleto EP-catalyzed hydrolysis.
1Fisiología Vegetal, Dept. de Biología Vegetal,Universidad de Alcalá de Henares, Present address: 28871Alcalá de Henares (Madrid), España. 相似文献
85.
Guirola M Urquiza D Alvarez A Cannan-Haden L Caballero E Guillén G 《FEMS immunology and medical microbiology》2006,46(2):169-179
In this study, we used an adoptive lymphocyte transfer experiment to evaluate the ability of the P64k recombinant protein to recruit T-helper activity and induce immunologic memory response to the polysaccharide moiety in a meningococcal serogroup C conjugate vaccine. Adoptive transfer of splenocytes from mice immunized with the glycoconjugate conferred antipolysaccharide immunologic memory to naive recipient mice. The observed anamnestic immune response was characterized by more rapid kinetics, isotype switching from IgM to IgG and higher antipolysaccharide antibody titers compared with those reached in groups transferred with splenocytes from plain polysaccharide or phosphate-immunized mice. The memory response generated was also long lasting. Sera from mice transferred with cells from conjugate-immunized mice were the only protective in the infant rat passive protection assay, and also showed higher bactericidal titers. We demonstrated that priming the mice immune system with the glycoconjugate using the P64k protein as carrier induced a memory response to the polysaccharide, promoting a switch of the T-cell-independent response to a T-cell dependent one. 相似文献
86.
87.
Spontaneously nalidixic acid-resistant lines (NAr lines) were selected from a V79 Chinese hamster cell line and phenotypically characterized. NAr lines showed an increased doubling time, a higher number of spontaneous SCE, and more interestingly, decreased DNA topoisomerase II activity. These lines were also cross-resistant to the eukaryotic topoisomerase II inhibitors etoposide and adriamycin, but showed the same level of sensitivity as the parental line to the DNA topoisomerase I inhibitor camptothecin. NAr lines were cross-resistant to other drugs, such as PALA, MTX and MPA, resistance to which has been shown to arise by amplification of the target genes. This last feature, together with enhanced cross-resistance to PALA and MTX when employed simultaneously, suggests that NAr lines have an 'amplification prone' phenotype. From these results the decreased activity of topoisomerase II seems to be involved in the generation of amplified sequences possibly by affecting recombinational events underlying gene amplification. 相似文献
88.
Ibrahim MM de Angelis R Lima AS Viana de Carvalho GD Ibrahim FM Malki LT de Paula Bichuete M de Paula Martins W Rocha EM 《PloS one》2012,7(3):e33775
Purpose
Fungi are a major cause of keratitis, although few medications are licensed for their treatment. The aim of this study is to observe the variation in commercialisation of antifungal eye drops, and to predict the seasonal distribution of fungal keratitis in Brazil.Methods
Data from a retrospective study of antifungal eye drops sales from the only pharmaceutical ophthalmologic laboratory, authorized to dispense them in Brazil (Opthalmos) were gathered. These data were correlated with geographic and seasonal distribution of fungal keratitis in Brazil between July 2002 and June 2008.Results
A total of 26,087 antifungal eye drop units were sold, with a mean of 2.3 per patient. There was significant variation in antifungal sales during the year (p<0.01). A linear regression model displayed a significant association between reduced relative humidity and antifungal drug sales (R2 = 0.17,p<0.01).Conclusions
Antifungal eye drops sales suggest that there is a seasonal distribution of fungal keratitis. A possible interpretation is that the third quarter of the year (a period when the climate is drier), when agricultural activity is more intense in Brazil, suggests a correlation with a higher incidence of fungal keratitis. A similar model could be applied to other diseases, that are managed with unique, or few, and monitorable medications to predict epidemiological aspects. 相似文献89.
JM Angeles Y Goto M Kirinoki M Asada LR Leonardo PT Rivera EA Villacorte N Inoue Y Chigusa S Kawazu 《PLoS neglected tropical diseases》2012,6(8):e1800
Background
The presence of animal reservoirs in Schistosoma japonicum infection has been a major obstacle in the control of schistosomiasis. Previous studies have proven that the inclusion of control measures on animal reservoir hosts for schistosomiasis contributed to the decrease of human cases. Animal surveillance should therefore be included to strengthen and improve the capabilities of current serological tests.Methodology/Principal Findings
Thioredoxin peroxidase-1 (SjTPx-1) and four tandem repeat proteins (Sj1TR, Sj2TR, Sj4TR, Sj7TR) were initially evaluated against human sera. The previous test showed high sensitivity and specificity for antibody detection against SjTPx-1 and Sj7TR. In this study, the immunodiagnostic potential of these recombinant proteins was evaluated using enzyme-linked immunoassay on 50 water buffalo serum samples collected in Cagayan, the Philippines as compared with the soluble egg antigen (SEA). For specificity, 3 goat serum samples positive with Fasciola hepatica were used and among the antigens used, only SEA showed cross-reaction. Stool PCR targeting the S. japonicum 82 bp mitochondrial NAD 1 gene was done to confirm the true positives and served as the standard test. Twenty three samples were positive for stool PCR. SjTPx-1 and Sj1TR gave the highest sensitivity among the recombinant proteins tested for water buffalo samples with 82.61% and 78.26% respectively which were higher than that of SEA (69.57%).Conclusions/Significance
These results prove that SjTPx-1 works both for humans and water buffaloes making it a good candidate antigen for zoonotic diagnosis. Sj1TR showed good results for water buffaloes and therefore can also be used as a possible candidate for detecting animal schistosome infection. 相似文献90.
David N. Gumieiro Bruna P. M. Rafacho Andrea F. Gon?alves Priscila P. Santos Paula S. Azevedo Leonardo A. M. Zornoff Gilberto J. C. Pereira Luiz S. Matsubara Sergio A. R. Paiva Marcos F. Minicucci 《PloS one》2013,8(2)