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101.
102.
Gonzalez MA Alvarez Mdel L Pisani GB Bernal CA Roma MG Carrillo MC 《Biological trace element research》2007,116(3):329-348
We have shown that aluminum (Al) induces cholestasis associated with multiple alterations in hepatocellular transporters involved
in bile secretory function, like Mrp2. This work aims to investigate whether these harmful effects are mediated by the oxidative
stress caused by the metal. For this purpose, the capability of the antioxidant agent, vitamin E, to counteract these alterations
was studied in male Wistar rats. Aluminum hydroxide (or saline in controls) was administered ip (27 mg/kg body weight, three
times a week, for 90 d). Vitamin E (600 mg/kg body weight) was coadministered, sc. Al increased lipid peroxidation (+50%)
and decreased hepatic glutation levels (-43%) and the activity of glutation peroxidase (-50%) and catalase (-88%). Vitamin
E counteracted these effects total or partially. Both plasma and hepatic Al levels reached at the end of the treatment were
significantly reduced by vitamin E (-40% and -44%, respectively;p< 0.05). Al increased 4 times the hepatic apoptotic index, and this effect was fully counteracted by vitamin E. Bile flow
was decreased in Al-treated rats (-37%) and restored to normality by vitamin E. The antioxidant normalized the hepatic handling
of the Mrp2 substrates, rose bengal, and dinitrophenyl-S-glutathione, which was causally associated with restoration of Mrp2
expression. Our data indicate that oxidative stress has a crucial role in cholestasis, apoptotic/necrotic hepatocellular damage,
and the impairment in liver transport function induced by Al and that vitamin E counteracts these harmful effects not only
by preventing free-radical formation but also by favoring Al disposal. 相似文献
103.
Neutrophils activate macrophages for intracellular killing of Leishmania major through recruitment of TLR4 by neutrophil elastase 总被引:5,自引:0,他引:5
Ribeiro-Gomes FL Moniz-de-Souza MC Alexandre-Moreira MS Dias WB Lopes MF Nunes MP Lungarella G DosReis GA 《Journal of immunology (Baltimore, Md. : 1950)》2007,179(6):3988-3994
We investigated the role of neutrophil elastase (NE) in interactions between murine inflammatory neutrophils and macrophages infected with the parasite Leishmania major. A blocker peptide specific for NE prevented the neutrophils from inducing microbicidal activity in macrophages. Inflammatory neutrophils from mutant pallid mice were defective in the spontaneous release of NE, failed to induce microbicidal activity in wild-type macrophages, and failed to reduce parasite loads upon transfer in vivo. Conversely, purified NE activated macrophages and induced microbicidal activity dependent on secretion of TNF-alpha. Induction of macrophage microbicidal activity by either neutrophils or purified NE required TLR4 expression by macrophages. Injection of purified NE shortly after infection in vivo reduced the burden of L. major in draining lymph nodes of TLR4-sufficient, but not TLR4-deficient mice. These results indicate that NE plays a previously unrecognized protective role in host responses to L. major infection. 相似文献
104.
Armengol R Pabón M Santolaria P Cabezón O Adelantado C Yániz J López-Gatius F Almería S 《The Journal of parasitology》2007,93(5):1029-1032
Neospora caninum seroprevalence and risk factors affecting seroprevalence in beef cattle in Andorra were investigated. Antibodies to N. caninum were evaluated by enzyme-linked immunosorbent assay performed on a yearly basis in 1,758 animals older than 6 mo, belonging to 26 herds. Mean seroprevalence of antibodies to N. caninum for the herds was 7.4 +/- 1.2% (130/1,758). Logistic regression analyses were performed on data from each animal, considering N. caninum seropositivity as the dependent variable, and herd, grazing area, year of sampling, repeat-test animal (animals sampled twice or more), sex, breed, age (animals <4 yr old or > or =5 yr old), and country of birth as possible risk factors. Based on the odds ratio, the prevalence of infection was 2.1 times higher (P < 0.01) in animals from the Ordino grazing area, 1.64 times higher in animals older than 5 yr (P < 0.01), and 6.7 times (1/0.15) lower in Limousin-mixed Limousin cattle (P < 0.002). The results suggest that the particular grazing location could promote the horizontal transmission of this parasite and that certain breeds are less susceptible to N. caninum infection than others. 相似文献
105.
Ceravolo GS Franco MC Carneiro-Ramos MS Barreto-Chaves ML Tostes RC Nigro D Fortes ZB Carvalho MH 《Life sciences》2007,80(8):782-787
Epidemiological studies suggest that intrauterine undernutrition plays an important role in the development of arterial hypertension and endothelial dysfunction in adulthood. We have evaluated the effect of the Renin Angiotensin System inhibition on the blood pressure and the mesenteric arteriolar reactivity of the intrauterine undernourished rats. Wistar rats were fed either normal or 50% of the normal intake diets, during the whole gestational period. In this study only the male offspring was used. At 16 weeks of age, the rats were used for the study of blood pressure, microvascular reactivity studied in vivo-in situ to Angiotensin II (Ang II), Bradykinin (Bk) and Acetylcholine (Ach) before and after either losartan (10 mg/kg/15 days) or enalapril (15 mg/kg/21 days) treatment. We also evaluated the mesenteric and plasmatic Angiotensin Converting Enzyme (ACE), renal function, lipid plasmatic content, and insulin and glucose metabolism. Intrauterine undernutrition induced hypertension and increased response of mesenteric arterioles to Ang II and decreased vasodilation to Bk and Ach. The treatments with losartan or enalapril normalized the blood pressure levels and significantly improved the arteriolar responses to Bk, Ach and reduced the response to Ang II. No differences have been detected to ACE activity, renal function, lipid content and insulin and glucose metabolism. This study shows for the first time that Renin Angiotensin System inhibitors can normalize the cardiovascular alterations induced by intrauterine undernutrition. 相似文献
106.
Aerobic bacteria, such as Burkholderia xenovorans LB400, are able to degrade a wide range of polychlorobiphenyls (PCBs). Generally, these bacteria are not able to transform
chlorobenzoates (CBAs), which accumulate during PCB degradation. In this study, the effects of CBAs on the growth, the morphology
and the proteome of Burkholderia
xenovorans LB400 were analysed. 4-CBA and 2-CBA were observed to inhibit the growth of strain LB400 on glucose. Strain LB400 exposed
to 4-CBA exhibited increased number and size of electron-dense granules in the cytoplasm, which could be polyphosphates. Two-dimensional
(2-D) polyacrylamide gel electrophoresis was used to characterise the molecular response of strain LB400 to 4-CBA. This compound
induced the enzymes BenD and CatA of benzoate and catechol catabolic pathways. The induction of molecular chaperones DnaK
and HtpG by 4-CBA indicated that the exposure to this compound constitutes a stressful condition for this bacterium. Additionally,
the induction of some Krebs cycle enzymes was observed, probably as response to cellular energy requirements. This study contributes
to the knowledge on the effects of CBA on the PCB-degrader Burkholderia xenovorans LB400. 相似文献
107.
Arteaga-Silva M Rodríguez-Dorantes M Baig S Morales-Montor J 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2007,147(3):607-615
Little is known about the hormonal regulation of sexual behavior and about the pattern of expression in the brain of sex-steroid receptors in the BALB/c AnN strain of mice (Mus musculus). In this study, 8-week old male BALB/c AnN mice were castrated and the temporal course of decline of sexual behavior was studied, as well as the effects of daily treatment with either testosterone propionate (TP), estradiol benzoate (EB), or dihydrotestosterone propionate (PDHT). Castration resulted in rapid decline of sexual behavior, in both control or vehicle-treated mice. TP maintained full sexual behavior of castrated mice, while PDHT or EB did not have this effect. The expression of ER-alpha dropped nearly 50% after castration, and this pattern remained in TP or PDHT-treated mice, while EB increased the ER-alpha mRNA levels to almost the same values as in intact control mice. The same pattern was found when ER-beta mRNA levels were analyzed. The expression of the PR-A/B gene in the different brain regions in intact mice and after castration, or among the differently treated mice, showed significant differences between normal and castrated mice at all times in all brain regions studied, with the exception of the frontal cortex. Castration reduced the expression of AR by 10-fold, as compared to intact control mice, while TP or PDHT treatment returned its expression to the same levels as in intact control mice, in all brain areas studied. The changes are more prominent in POA-HIP than in HYP and CF. These results demonstrated a rapid decline of sexual behavior in this strain of mice after castration, and show that only TP was able to maintain male sexual behavior, with no correlation with the pattern of expression of sex hormone receptors in specific areas of the mouse brain. 相似文献
108.
Armando Vega-Lpez Marcela Galar-Martínez Fausto Alejandro Jimnez-Orozco Ethel García-Latorre Maria Lilia Domínguez-Lpez 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2007,146(4):672
Polychlorinated biphenyls (PCBs) are persistent xenobiotics within aquatic environments, which elicit diverse toxic effects such as induction of oxidative stress. Despite numerous earlier studies, no detailed information exists on the toxic response by different sexes in fish. The aim of this study was to determine sex-linked differences in oxidative stress response and antioxidant defenses in Girardinichthys viviparus, an endangered fish endemic to Mexico, when exposed to sub-lethal concentrations of waterborne PCBs. The biological markers evaluated were lipid peroxidation (LPOX), superoxide dismutase (SOD) and catalase (CAT) activity. Adult eight-month-old specimens born in the laboratory were exposed to ½ of the LC0 (0.92 mg PCBs/L) in semi-hard synthetic water and sacrificed on days 1, 2, 4, 8 and 16 for biomarker assays. Sex-linked differences were observed in the control fish with respect to all three factors assayed. PCBs elicited significant (p < 0.01) time- and sex-dependent LPOX levels which were higher in the case of males. In PCB-treated G. viviparus, SOD activity was depressed in both sexes and appears to return to pre-exposure levels after 16 days in males only. In contrast, CAT was significantly induced (p < 0.01) in both sexes. This enzyme may be responsible for balancing oxidative stress and antioxidant defenses under experimental conditions. PCBs at sub-lethal concentrations are hazardous to both sexes of G. viviparus since these compounds are able to induce liver LPOX and changes in the antioxidant defense activities. The relationship between these biomarkers and cytochrome P450 and CYP1A induction is also discussed. 相似文献
109.
110.
DosReis GA Ribeiro-Gomes FL Guillermo LV Lopes MF 《Cytokine & growth factor reviews》2007,18(1-2):97-105
Parasitic diseases have worldwide medical and economical impact. Host T lymphocytes and the cytokines they produce determine the outcome of parasitic infections. Programmed cell death by apoptosis is induced in the course of parasitic infections, and affects cytokine production by removing activated effector T and B cells. In addition, engulfment of apoptotic cells promotes the secretion of cytokines that regulate intracellular replication of protozoan parasites. In this review, we discuss how the cross-talk between apoptosis and cytokines regulates parasitic infection. 相似文献