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排序方式: 共有311条查询结果,搜索用时 281 毫秒
201.
Paulina Pettinelli Talía del Pozo Julia Araya Ramón Rodrigo A. Verónica Araya Gladys Smok Attila Csendes Luis Gutierrez Jorge Rojas Owen Korn Fernando Maluenda Juan C. Diaz Guillermo Rencoret Italo Braghetto Jaime Castillo Jaime Poniachik Luis A. Videla 《生物化学与生物物理学报:疾病的分子基础》2009,1792(11):1080-1086
Sterol receptor element-binding protein-1c (SREBP-1c) and peroxisome proliferator-activated receptor-α (PPAR-α) mRNA expression was assessed in liver as signaling mechanisms associated with steatosis in obese patients. Liver SREBP-1c and PPAR-α mRNA (RT-PCR), fatty acid synthase (FAS) and carnitine palmitoyltransferase-1a (CPT-1a) mRNA (real-time RT-PCR), and n-3 long-chain polyunsaturated fatty acid (LCPUFA)(GLC) contents, plasma adiponectin levels (RIA), and insulin resistance (IR) evolution (HOMA) were evaluated in 11 obese patients who underwent subtotal gastrectomy with gastro-jejunal anastomosis in Roux-en-Y and 8 non-obese subjects who underwent laparoscopic cholecystectomy (controls). Liver SREBP-1c and FAS mRNA levels were 33% and 70% higher than control values (P < 0.05), respectively, whereas those of PPAR-α and CPT-1a were 16% and 65% lower (P < 0.05), respectively, with a significant 62% enhancement in the SREBP-1c/PPAR-α ratio. Liver n-3 LCPUFA levels were 53% lower in obese patients who also showed IR and hipoadiponectinemia over controls (P < 0.05). IR negatively correlated with both the hepatic content of n-3 LCPUFA (r = ? 0.55; P < 0.01) and the plasma levels of adiponectin (r = ? 0.62; P < 0.005). Liver SREBP-1c/PPAR-α ratio and n-3 LCPUFA showed a negative correlation (r = ? 0.48; P < 0.02) and positive associations with either HOMA (r = 0.75; P < 0.0001) or serum insulin levels (r = 0.69; P < 0.001). In conclusion, liver up-regulation of SREBP-1c and down-regulation of PPAR-α occur in obese patients, with enhancement in the SREBP-1c/PPAR-α ratio associated with n-3 LCPUFA depletion and IR, a condition that may favor lipogenesis over FA oxidation thereby leading to steatosis. 相似文献
202.
A Nuclear Gene Encoding the Iron-Sulfur Subunit of Mitochondrial Complex II Is Regulated by B3 Domain Transcription Factors during Seed Development in Arabidopsis
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203.
Swearingen JW Fuentes DE Araya MA Plishker MF Saavedra CP Chasteen TG Vásquez CC 《Applied and environmental microbiology》2006,72(1):963-967
The ubiE gene of Geobacillus stearothermophilus V, with its own promoter, was cloned and introduced into Escherichia coli. The cloned gene complemented the ubiE gene deficiency of E. coli AN70. In addition, the expression of this gene in E. coli JM109 resulted in the evolution of volatile selenium compounds when these cells were grown in selenite- or selenate-amended media. These compounds were dimethyl selenide and dimethyl diselenide. 相似文献
204.
Iron and copper and essential microminerals that are intimately related. The present study was performed to determine the
effect of iron-deficiency anemia (IDA) and treatment with iron on laboratory indicators of copper status. Hemoglobin, mean
corpuscular volume erythrocyte Zn protoporphyrin, serum ferritin, serum copper, serum ceruloplasmin, and erythrocyte CuZn-superoxide
dismutase (SOD) activity were studied in 12 adult women with IDA before and after iron treatment for 60–90 d (100 mg/d Fe,
as ferric polymaltose) and in 27 women with normal iron status. Prior to treatment with iron, serum copper and ceruloplasmin
were not different between the groups and treatment with iron did not affect these measures. IDA women, before and after treatment
with iron, presented a 2.9- and 2-fold decrease in erythrocyte CuZn-SOD activity compared to women with normal iron status
(p <0.001). Treatment with iron increased erythrocyte CuZn-SOD activity of the IDA group; however, this change was not statistically
significant. in conclusion, CuZn-SOD activity is decreased in IDA. Measurement of this enzyme activity is not useful for evaluating
copper nutrition in iron-deficient subjects. 相似文献
205.
Insulin resistance and oxidative stress interdependency in non-alcoholic fatty liver disease 总被引:5,自引:0,他引:5
Non-alcoholic fatty liver disease (NAFLD) is emerging as a major cause of chronic liver disease in association with the rising prevalence of obesity and type 2 diabetes in the population. Oxidative stress and insulin resistance (IR) are major contributors in the pathogenesis of NAFLD and in the progression from steatosis to steatohepatitis. Recently, Houstis and colleagues reported that reactive oxygen species have a causal role in multiple forms of IR, a phenomenon that can further promote exacerbation of oxidative stress. The improvement of the knowledge of these interrelationships should contribute to elucidate pathogenic pathways and design effective treatments for NAFLD. 相似文献
206.
Fukuda T Scott G Komatsu Y Araya R Kawano M Ray MK Yamada M Mishina Y 《Genesis (New York, N.Y. : 2000)》2006,44(4):159-167
BMP signaling plays pleiotropic roles in various tissues. Transgenic mouse lines that overexpress BMP signaling in a tissue-specific manner would be beneficial; however, production of each tissue-specific transgenic mouse line is labor-intensive. Here, using a Cre-loxP system, we generated a conditionally overexpressing mouse line for BMP signaling through the type I receptor ALK2 (alternatively known as AVCRI, ActRI, or ActRIA). By mating this line with Cre-expression mouse lines, Cre-mediated recombination removes an intervening floxed lacZ expression cassette and thereby permits the expression of a constitutively active form of Alk2 (caAlk2) driven by a ubiquitous promoter, CAG. Tissue specificity of Cre recombination was monitored by a bicistronically expressed EGFP following Alk2 cDNA. Increased BMP signaling was confirmed by ectopic phosphorylation of SMAD1/5/8 in the areas where Cre recombination had occurred. The conditional overexpression system described here provides versatility in investigating gene functions in a tissue-specific manner without having to generate independent tissue-specific transgenic lines. 相似文献
207.
Background
Two categories of introns are known, a common U2 type and a rare U12 type. These two types of introns are removed by distinct spliceosomes. The phylogenetic distribution of spliceosomal RNAs that are characteristic of the U12 spliceosome, i.e. the U11, U12, U4atac and U6atac RNAs, suggest that U12 spliceosomes were lost in many phylogenetic groups. We have now examined the distribution of U2 and U12 introns in many of these groups.Results
U2 and U12 introns were predicted by making use of available EST and genomic sequences. The results show that in species or branches where U12 spliceosomal components are missing, also U12 type of introns are lacking. Examples are the choanoflagellate Monosiga brevicollis, Entamoeba histolytica, green algae, diatoms, and the fungal lineage Basidiomycota. Furthermore, whereas U12 splicing does not occur in Caenorhabditis elegans, U12 introns as well as U12 snRNAs are present in Trichinella spiralis, which is deeply branching in the nematode tree. A comparison of homologous genes in T. spiralis and C. elegans revealed different mechanisms whereby U12 introns were lost.Conclusions
The phylogenetic distribution of U12 introns and spliceosomal RNAs give further support to an early origin of U12 dependent splicing. In addition, this distribution identifies a large number of instances during eukaryotic evolution where such splicing was lost. 相似文献208.
Miguel Arredondo Héctor Núñez Guadalupe López Fernando Pizarro Mariana Ayala Magdalena Araya 《Biological trace element research》2010,134(3):252-264
Classic copper indicators are not sensitive and specific for detecting excess copper exposure when this is higher than customary
but not markedly elevated. Serum copper and ceruloplasmin (Cp) are the most commonly used indicators to assess nutritional
status of copper. The objective of this paper was to study the influence of estrogens on these indicators and others used
to assess early effects of excess copper exposure in humans and the expression of a set of copper related proteins in a hepatic
cellular model. For the studies in humans, 107 healthy participants (18–50 years) were allocated as follows: group 1 (n = 39), women assessed on day 7 of their hormonal cycle; group 2 (n = 34), women assessed on day 21 of their hormonal cycle, and group 3 (n = 34, comparison group), healthy men. Participants received 8 mg Cu/day (as copper sulfate) during 6 months. Serum Cp and
Cu, Cu–Zn–superoxide dismutase activity, liver function indicators [aspartate aminotransferase (AST), alanine aminotransferase
(ALT), and gamma glutamyltransferase (GGT)], and serum Fe and Zn concentrations were measured monthly. In addition, the influence
of estradiol on intracellular total copper content, hctr1, dmt1 and shbg mRNA abundance and hCTR1, and DMT1 expression was
measured in HepG2 cells. Serum Cu, Fe, and Zn and liver aminotransferases but not Cu–Zn–superoxide dismutase varied depending
on sex. Fe nutrition indicators, GGT, and ALT activities showed significant differences between the hormonal phases. Cellular
experiments showed that estradiol increased cellular Cu concentration and hCTR1 and DMT1 mRNA expression and changed these
proteins expression patterns. Estradiols significantly influence the responses to copper at the whole body and the cellular
levels, suggesting that they help maintaining copper availability for metabolic needs. 相似文献
209.
Olmedo I Araya E Sanz F Medina E Arbiol J Toledo P Alvarez-Lueje A Giralt E Kogan MJ 《Bioconjugate chemistry》2008,19(6):1154-1163
In a previous work, we studied the interaction of beta-amyloid fibrils (Abeta) with gold nanoparticles (AuNP) conjugated with the peptide CLPFFD-NH2. Here, we studied the effect of changing the residue sequence of the peptide CLPFFD-NH2 on the efficiency of conjugation to AuNP, the stability of the conjugates, and the affinity of the conjugates to the Abeta fibrils. We conjugated the AuNP with CLPFFD-NH 2 isomeric peptides (CDLPFF-NH2 and CLPDFF-NH2) and characterized the resulting conjugates with different techniques including UV-Vis, TEM, EELS, XPS, analysis of amino acids, agarose gel electrophoresis, and CD. In addition, we determined the proportion of AuNP bonded to the Abeta fibrils by ICP-MS. AuNP-CLPFFD-NH2 was the most stable of the conjugates and presented more affinity for Abeta fibrils with respect to the other conjugates and bare AuNP. These findings help to better understand the way peptide sequences affect conjugation and stability of AuNP and their interaction with Abeta fibrils. The peptide sequence, the steric effects, and the charge and disposition of hydrophilic and hydrophobic residues are crucial parameters when considering the design of AuNP peptide conjugates for biomedical applications. 相似文献
210.
Elizondo A Araya J Rodrigo R Signorini C Sgherri C Comporti M Poniachik J Videla LA 《Biological research》2008,41(1):59-68
Our aim was to study the influence of weight loss on the fatty acid (FA) composition of liver and erythrocyte phospholipids and oxidative stress status in obese, non-alcoholic, fatty liver disease (NAFLD) patients. Seven obese NAFLD patients who underwent subtotal gastrectomy with a gastro-jejunal anastomosis in roux and Y were studied immediately and 3 months after surgery. Seven non-obese patients who underwent anti-reflux surgery constituted the control group. Serum F2-isoprostane levels were measured by GS/NICI-MS/MS and FA composition was determined by GC. At the time of surgery, controls and obese patients exhibited a hepatic polyunsaturated fatty acid (PUFA) pattern that correlated with that of erythrocytes. Three months after surgery, NAFLD patients lost 21% of initial body weight; serum F2-isoprostane levels decreased by 76%; total PUFA, long-chain PUFA (LCPUFA), n-3 PUFA, and n-3 LCPUFA increased by 22, 29, 81, and 93%, respectively; n-6/n-3 LCPUFA ratio decreased by 51%; docosahexaenoic acid/docosapentaenoic acid ratio increased by 19-fold; and the n-3 product/precursor ratio (20: 5 + 22: 5 + 22: 6)/18: 3 increased by 164% (p<0.05). It is concluded that weight loss improves the n-3 LCPUFA status of obese patients in association with significant amelioration in the biomarkers of oxidative stress, membrane FA insaturation, and n-3 LCPUFA biosynthesis capacity, thus representing a central therapeutic issue in the improvement of obesity-related metabolic alterations involved in the mechanism of hepatic steatosis. 相似文献