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31.
Oxidative stress, nitric oxide production, and renal sodium handling in leptin-induced hypertension 总被引:4,自引:0,他引:4
Chronic hyperleptinemia induces arterial hypertension in experimental animals and may contribute to the development of hypertension in obese humans; however, the mechanism of hypertensive effect of leptin is not completely elucidated. We investigated the effect of leptin on whole-body oxidative stress, nitric oxide production, and renal sodium handling. The study was performed on male Wistar rats divided into 3 groups: 1) control, fed standard chow ad libitum, 2) leptin-treated group, receiving leptin injections (0.25 mg/kg twice daily s.c. for 7 days), 3) pair-fed group, in which food intake was adjusted to the leptin group. Leptin caused 30.5% increase in systolic blood pressure. Plasma concentration and urinary excretion of 8-isoprostanes in animals receiving leptin was 46.4% and 49.2% higher, respectively. The level of lipid peroxidation products, malonyldialdehyde + 4-hydroxyalkenals, increased by 52.5% in the renal cortex and by 48.4% in the renal medulla following leptin treatment, whereas aconitase activity decreased in these regions of the kidney by 45.3% and 39.2%, respectively. Urinary excretion of nitric oxide metabolites (NOx) was 55.0% lower, and fractional excretion of NOx was 55.8% lower in the leptin-treated group. Urinary excretion of cGMP decreased in leptin-treated rats by 26.3%. Following leptin treatment, absolute and fractional sodium excretion decreased by 35.0% and 41.2%, respectively. These results indicate that hyperleptinemia induces systemic and intrarenal oxidative stress, decreases the amount of bioactive NO possibly due to its degradation by reactive oxygen species, and causes renal sodium retention by stimulating tubular sodium reabsorption. NO deficiency and abnormal renal Na+ handling may contribute to leptin-induced hypertension. 相似文献
32.
Equilibrium and dynamic investigations of organic acids adsorption onto ion-exchange resins 总被引:2,自引:0,他引:2
The aim of the study was to determine properties of selected ion-exchange resins for citric and lactic acids recovery, to define sorption isotherms for these acids at different temperatures (in the range of 20–60°C) and to determine diffusion coefficients inside sorbent particles. A mathematical model of the ion-exchange process in the chromatographic column and its experimental verification is also presented. During investigations 18 types of ion-exchange resins were tested. It was found that weakly basic resins were more suitable for the recovery process than strongly basic ones. The best resin for the separation of citric acid was Amberlite IRA-67 and for lactic acid Amberlite IRA-92. As a result of transient-state sorption experiments diffusion coefficients of the citric acid inside the sorbent particle at different temperatures were obtained. It was found that Dp increased with the temperature by two times in the range of 20–60°C, and its value at 60°C was 7.2×10–10 m2/s. The proposed mathematical model was applied to identify bed operation parameters in the column for the needs of the simulated moving bed chromatography method.List of symbols b Equilibrium constant in Langmuir equation, [dm3/g] - c Acid concentration in the liquid phase inside the particle pores, [g/dm3] - C Acid concentration in the liquid, [g/dm3] - DL Axial dispersion coefficient, [m2/s] - Dp Intraparticle diffusion coefficient, [m2/s] - kf Liquid film mass transfer coefficient, [m/s] - L Ion-exchanger bed height, [m] - q Acid concentration in the adsorbent phase, [g/dm3] - Rp Particle radius, [m] - U Volumetric flow rate of the feeding solution, [dm3/s] - V Volume of the solution, [dm3] - W Weight of the wet resin particles, [g] - The ion-exchanger bed porosity, [-] - p Particle porosity, [-] - Linear liquid velocity, [m/s] - Apparent density of the wet resin, [g/dm3] 相似文献
33.
The estimation of the amount of evolutionary divergence that has taken
place between two DNA coding sequences depends strongly on the degree of
constraint on amino acid replacements. If amino acid replacements are
relatively unconstrained, the individual nucleotide is the appropriate unit
of analysis and the method of Tajima and Nei can be used. If amino acid
replacements are constrained, however, this method is shown to be
inapplicable. For sequences with strong amino acid constraints, a method is
outlined analogous to the Tajima and Nei method using codons as the unit of
analysis. Only synonymous substitutions are used. Codon usage data can be
employed to estimate the necessary parameters of the calculation, or a
priori models of substitution may be employed. Sequences with significant
but intermediate constraints on amino acid replacements are, in principle,
unanalyzable.
相似文献
34.
Mitogenic activity of pituitary hormones on cell cultures of normal and carcinogen-induced tumor epithelium from rat mammary glands 总被引:5,自引:2,他引:3 下载免费PDF全文
Cell suspension containing normal or tumor epithelium were readily obtained by enzymatically digesting rat mammary glands from perphenazine-treated (prolactin-hypersecreting) cycling, female virgin animals or hormone- responsive mammary tumors from animal treated with dimethylbenzanthracene. Cell suspensions were fractioned into predominantly epithelial and predominantly stromal cells by their differential rates of attachment to culture dishes. Both normal mammary and tumor epithelial cells were characterized by the presence of specific cell-junctional complexes, desmosome-like structures, surface microvilli, and their ability to synthesize casein. Serum-dependent protease activity was greater in cultures derived from tumors, and cells from such cultures grew in agarose whereas those from the non-neoplastic gland did not. The addition of prolactin to the culture medium stimulated DNA synthesis in primary or secondary epithelial cultures from tumors, whereas additional insulin and hydrocortisone with prolactin were required for similar levels of DNA synthesis in cultures from non-neoplastic glands. The fraction of cells synthesizing DNA was, however, smaller than that with 10 percent serum measured in the same time period. Both growth hormone and epidermal growth factor stimulated DNA synthesis but to a lesser extent than did prolactin. Prolactin with hydrocortisone and insulin were relatively inactive in promoting DNA synthesis of the nonepithelial cells whereas pituitary fibroblast growth factor was more active. These mitogenic effects were obtained when the hormones were added to the medium at near physiological concentrations, and paralleled the known activities of the hormones in control of mammary gland growth and development in the rat. 相似文献
35.
A Pseudomonas aeruginosa TIR effector mediates immune evasion by targeting UBAP1 and TLR adaptors 下载免费PDF全文
Paul RC Imbert Arthur Louche Jean‐Baptiste Luizet Teddy Grandjean Sarah Bigot Thomas E Wood Stéphanie Gagné Amandine Blanco Lydia Wunderley Laurent Terradot Philip Woodman Steve Garvis Alain Filloux Benoit Guery Suzana P Salcedo 《The EMBO journal》2017,36(13):1869-1887
Bacterial pathogens often subvert the innate immune system to establish a successful infection. The direct inhibition of downstream components of innate immune pathways is particularly well documented but how bacteria interfere with receptor proximal events is far less well understood. Here, we describe a Toll/interleukin 1 receptor (TIR) domain‐containing protein (PumA) of the multi‐drug resistant Pseudomonas aeruginosa PA7 strain. We found that PumA is essential for virulence and inhibits NF‐κB, a property transferable to non‐PumA strain PA14, suggesting no additional factors are needed for PumA function. The TIR domain is able to interact with the Toll‐like receptor (TLR) adaptors TIRAP and MyD88, as well as the ubiquitin‐associated protein 1 (UBAP1), a component of the endosomal‐sorting complex required for transport I (ESCRT‐I). These interactions are not spatially exclusive as we show UBAP1 can associate with MyD88, enhancing its plasma membrane localization. Combined targeting of UBAP1 and TLR adaptors by PumA impedes both cytokine and TLR receptor signalling, highlighting a novel strategy for innate immune evasion. 相似文献
36.
Díaz López E A Morales Ruíz EJ Vargas Ramírez P Hernández Herrera RC Reséndiz Melgar I Brena Hernández JM Loeza Corte 《Phyton》2015,84(2):319-330
The effect of six phosphorus levels (0, 40, 80, 120, 160 and 200 kg/ha) on the duration of cumulative leaf area, biomass and agronomic yield was determined in the maize cultivars: Amarillo Almoloya, Cacahuacintle and Condor in 2010 and 2011. Such cultivars were sown in the Cerrillo Piedras Blancas Mexico. A completely randomized complete block design with factorial arrangement was utilized. High phosphorus levels (120, 160 and 200 kg/ha) positively affected the duration of cumulative leaf area; greatest values were obtained in Cacahuacintle. A greater duration of accumulated leaf area contributes to determine high values of biomass accumulation and grain yield in this cultivar. Leaf area duration appeared to be a useful tool for evaluating different genotypes in a given environment. 相似文献
37.
38.
Simon E Brill Anant RC Patel Richa Singh Alexander J Mackay Jeremy S Brown John R Hurst 《Respiratory research》2015,16(1)
Background
Exacerbations of non-cystic fibrosis bronchiectasis cause significant morbidity but there are few detailed data on their clinical course and associated physiological changes. The biology of an exacerbation has not been previously described.The purpose of this study was to describe changes in lung function, symptoms, health status and inflammation during the development and recovery from community-treated exacerbations.Methods
This was a prospective observational cohort study of 32 outpatients with non-cystic fibrosis bronchiectasis conducted between August 2010 and August 2012. Patients completed a symptom diary card and measured their peak expiratory flow rate (PEFR) daily. Exacerbations were defined as oral antibiotic treatment taken for a worsening of respiratory symptoms. Symptoms and peak flow at exacerbation were analysed, and further measurements including the COPD Assessment Test (CAT) and inflammatory markers were also compared to baseline values.Results
At baseline, health status was significantly related to lung function, prognostic severity and systemic inflammation. 51 exacerbations occurred in 22 patients. Exacerbation symptoms began a median (interquartile range) of 4 (2, 7) days before treatment started and the median exacerbation duration was 16 (10, 29) days. 16% had not recovered by 35 days. At exacerbation, mean PEFR dropped by 10.6% (95% confidence interval 6.9-14.2, p < 0.001) and mean CAT score increased by 6.3 units (3.6-9.1, p = 0.001), median symptom count by 4 (2.25, 6, p < 0.001), and mean CRP by 9.0mg/L (2.3-15.8, p = 0.011). Exacerbations where PEFR fell by ≥10% were longer with more symptoms at onset.Conclusion
Exacerbations of non-CF bronchiectasis are inflammatory events, with worsened symptoms, lung function and health status, and a prolonged recovery period. Symptom diary cards, PEFR and CAT scores are responsive to changes at exacerbation and may be useful tools for their detection and monitoring.Electronic supplementary material
The online version of this article (doi:10.1186/s12931-015-0167-9) contains supplementary material, which is available to authorized users. 相似文献39.
Paprocka J Jamroz E Kalina M Kalina-Faska B Malecka-Tendera E Marszal E 《Neuro endocrinology letters》2007,28(5):545-546
Angelman Syndrome (AS, MIM 105830), classified among neurogenetic disorders, occurs with estimated frequency of 1:10 000 to 1:40 000. The characteristics features apart from neurodevelopmental impairment and seizures include peculiar face traits, absent speech, outburst of laughter, ataxia, stereotyped jerky (puppet-like) movements. The authors report three children with Angelman syndrome who were also diagnosed with hypothyroidism. 相似文献
40.
Cultures of Saccharomyces cerevisiae were subjected to the effect of PEF (pulse electric field) and a source of selenium. The culture period after which yeast cells were subjected to PEF treatment was optimized, as was the duration of the exposure. Optimization of the nutrient medium composition in S. cerevisiae cultures resulted in an over 1.8-fold increase in selenium accumulation with relation to cultures on the initial substrate. Optimization of the pH value and of culture duration resulted in selenium accumulation increase by approximately 78%. A significant correlation was found between the accumulation of selenium in yeast cells and its concentration in the culture substrate. The highest accumulation of selenium in the biomass of yeast, approx. 240 microg/g d.m., was obtained after 15-min exposure to PEF on a 20-h culture. An approx. 50% higher content of selenium in cells was recorded, as compared with the control culture without the application of PEF. 相似文献