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排序方式: 共有220条查询结果,搜索用时 250 毫秒
31.
32.
Morsy MA Abdalla AM Mahmoud AM Abdelwahab SA Mahmoud ME 《Journal of physiology and biochemistry》2012,68(1):29-35
Liver fibrosis is a major health problem that can lead to the development of liver cirrhosis and hepatocellular carcinoma.
On the other hand, several antioxidants have been shown to possess protective effect against liver fibrosis. Therefore, in
the present work, the effectiveness of curcumin, α-lipoic acid, and N-acetylcysteine in protecting against carbon tetrachloride (CCl4)-induced liver fibrosis as well as the mechanism(s) implicated in this protective effect was studied. The antioxidants used
in this study resulted in hepatoprotective effect as evident by substantial decreases in collagen deposition in histopathological
examinations in addition to significant decrease in serum levels of alanine aminotransferase, aspartate aminotransferase,
gamma glutamyl transpeptidase, bilirubin, and transforming growth factor-alpha (TGF-α) as well as hepatic malondialdehyde
concentration, with a concurrent increase in serum matrix metalloproteinase-13 (MMP-13) and hepatic reduced glutathione (GSH)
levels as compared to CCl4 fibrotic group. In conclusion, curcumin, α-lipoic acid, and N-acetylcysteine protect rats against CCl4-induced liver fibrosis most possibly through their antioxidant activities and their capacities to induce MMP-13 and to inhibit
TGF-α levels. 相似文献
33.
Mariarosaria Bucci Andreas Papapetropoulos Valentina Vellecco Zongmin Zhou Altaany Zaid Panagiotis Giannogonas Anna Cantalupo Sandeep Dhayade Katia P. Karalis Rui Wang Robert Feil Giuseppe Cirino 《PloS one》2012,7(12)
A growing body of evidence suggests that hydrogen sulfide (H2S) is a signaling molecule in mammalian cells. In the cardiovascular system, H2S enhances vasodilation and angiogenesis. H2S-induced vasodilation is hypothesized to occur through ATP-sensitive potassium channels (KATP); however, we recently demonstrated that it also increases cGMP levels in tissues. Herein, we studied the involvement of cGMP-dependent protein kinase-I in H2S-induced vasorelaxation. The effect of H2S on vessel tone was studied in phenylephrine-contracted aortic rings with or without endothelium. cGMP levels were determined in cultured cells or isolated vessel by enzyme immunoassay. Pretreatment of aortic rings with sildenafil attenuated NaHS-induced relaxation, confirming previous findings that H2S is a phosphodiesterase inhibitor. In addition, vascular tissue levels of cGMP in cystathionine gamma lyase knockouts were lower than those in wild-type control mice. Treatment of aortic rings with NaHS, a fast releasing H2S donor, enhanced phosphorylation of vasodilator-stimulated phosphoprotein in a time-dependent manner, suggesting that cGMP-dependent protein kinase (PKG) is activated after exposure to H2S. Incubation of aortic rings with a PKG-I inhibitor (DT-2) attenuated NaHS-stimulated relaxation. Interestingly, vasodilatory responses to a slowly releasing H2S donor (GYY 4137) were unaffected by DT-2, suggesting that this donor dilates mouse aorta through PKG-independent pathways. Dilatory responses to NaHS and L-cysteine (a substrate for H2S production) were reduced in vessels of PKG-I knockout mice (PKG-I−/−). Moreover, glibenclamide inhibited NaHS-induced vasorelaxation in vessels from wild-type animals, but not PKG-I−/−, suggesting that there is a cross-talk between KATP and PKG. Our results confirm the role of cGMP in the vascular responses to NaHS and demonstrate that genetic deletion of PKG-I attenuates NaHS and L-cysteine-stimulated vasodilation. 相似文献
34.
Talior-Volodarsky I Randhawa VK Zaid H Klip A 《The Journal of biological chemistry》2008,283(37):25115-25123
Insulin induces GLUT4 translocation to the muscle cell surface. Using differential amino acid labeling and mass spectrometry, we observed insulin-dependent co-precipitation of actinin-4 (ACTN4) with GLUT4 (Foster, L. J., Rudich, A., Talior, I., Patel, N., Huang, X., Furtado, L. M., Bilan, P. J., Mann, M., and Klip, A. (2006) J. Proteome Res. 5, 64-75). ACTN4 links F-actin to membrane proteins, and actin dynamics are essential for GLUT4 translocation. We hypothesized that ACTN4 may contribute to insulin-regulated GLUT4 traffic. In L6 muscle cells insulin, but not platelet-derived growth factor, increased co-precipitation of ACTN4 with GLUT4. Small interfering RNA-mediated ACTN4 knockdown abolished the gain in surface-exposed GLUT4 elicited by insulin but not by platelet-derived growth factor, membrane depolarization, or mitochondrial uncoupling. In contrast, knockdown of alpha-actinin-1 (ACTN1) did not prevent GLUT4 translocation by insulin. GLUT4 colocalized with ACTN4 along the insulin-induced cortical actin mesh and ACTN4 knockdown prevented GLUT4-actin colocalization without impeding actin remodeling or Akt phosphorylation, maintaining GLUT4 in a tight perinuclear location. We propose that ACTN4 contributes to GLUT4 traffic, likely by tethering GLUT4 vesicles to the cortical actin cytoskeleton. 相似文献
35.
Regulation of pharyngeal motility by FMRFamide and related peptides in the medicinal leech, Hirudo medicinalis 总被引:1,自引:0,他引:1
36.
In this article, we construct an approximate EM algorithm to estimate the parameters of a nonlinear mixed effects model. The iterative procedure can be viewed as an iterative method of moments procedure for estimating the variance components and an iterative reweighted least squares estimates for estimating the fixed effects. Therefore, it is valid without the normality assumptions on the random components. A computationally simple method of moments estimates of the model parameters are used as the starting values for our iterative procedure. A simulation study was conducted to compare the performances of the proposed procedure with the procedure proposed by Lindstrom and Bates (1990) for some normal models and nonnormal models. 相似文献
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38.
Zaid Al Rubaiee Haider Al Murayati Jan Tøttrup Nielsen Anders Pape Møller 《Ecology and evolution》2017,7(24):10797-10803
Predation is a powerful selective force with important effects on behavior, morphology, life history, and evolution of prey. Parasites may change body condition, health status, and ability to escape from or defend prey against predators. Once a prey individual has been detected, it can rely on a diversity of means of escape from the pursuit by the predator. Here we tested whether prey of a common raptor differed in terms of fungi from nonprey recorded at the same sites using the goshawk Accipiter gentilis and its avian prey as a model system. We found a positive association between the probability of falling prey to the raptor and the presence and the abundance of fungi. Birds with a specific composition of the community of fungi had higher probability of falling prey to a goshawk than individual hosts with fewer fungi. These findings imply that fungi may play a significant role in predator–prey interactions. The probability of having damaged feathers increased with the number of fungal colonies, and in particular the abundance of Myceliophthora verrucos and Schizophyllum sp. was positively related to the probability of having damaged feathers. In addition, we found a significant correlation between the rate of feather growth of goshawk prey with birds with more fungi being more likely to be depredated. These findings are consistent with the hypothesis that survival and feather quality of birds are related to abundance and diversity of fungi. 相似文献
39.
Heterologous expression of Mytilus californianus foot protein three (Mcfp-3) in Kluyveromyces lactis
Platko JD Deeg M Thompson V Al-Hinai Z Glick H Pontius K Colussi P Taron C Kaplan DL 《Protein expression and purification》2008,57(1):57-62
Mytilus californianus foot protein three (Mcfp-3) was successfully expressed in the yeast, Kluyveromyces lactis. The first nine amino acids (YPYDVPDYA) from the human-influenza-virus hemagglutinin (HA) protein were fused to the amino terminus of Mcfp-3 (HA-Mcfp-3) to facilitate identification and purification. HA-Mcfp-3 was purified to a concentration of 1mg/L using HA affinity chromatography. The recovered polypeptide was resolved by SDS-PAGE and migrated primarily at 36 kDa, an increase of approximately 29 kDa over the calculated molecular weight of a HA-Mcfp-3 monomer. Significantly, release of Mcfp-3 by enterokinase treatment coincided with the formation of high molecular weight complexes. It is noteworthy that the complexes mimicked the previously reported insolubility of Mcfps found in vivo to denaturing and reducing conditions. These data demonstrate the successful expression of Mcfp-3 in K. lactis and show an intrinsic ability of Mcfp-3 to self-assemble into stable, higher molecular weight forms. 相似文献
40.