Excreção de amônia por tambaqui (Colossoma macropomum) de acordo com variações na temperatura da água e massa do peixe.

O objetivo deste trabalho foi quantificar taxas de excreção diária de amônia em tambaqui (Colossoma macropomum), principal espécie criada na Amazônia, que podem variar de acordo com a temperatura da água e a massa dos peixes

Structural and Electronic Properties of Graphene Oxide for Different Degree of Oxidation1

In the last year, the investigation of two-dimensional materials as graphene oxide is a fundamental goal to produce innovative devices with wide range of applications in many areas. In the present work, we report a systematic study of structural and electronic properties of graphene oxide for different oxidations levels (25%, 50%, 75%, 100%) using density functional calculations for electronic ground state and a statistical approach on carbon-carbon bond length obtained after the geometric optimization of graphene covered with epoxide and hydroxyl functional groups. The theoretical models proposed and studied here are accord with the well-known experimental data. Our statistical results of the carbon-carbon bond length shown that hydroxyl groups disturbs the structure of graphene more than epoxide groups, however, both hydroxyl and epoxide groups are responsible of the change of hybridization sp2 to sp3, while the degree of oxidation increase. In addition, our electronic structure calculations confirm that with low degree of oxidation, the graphene oxide is semiconductor, and with full degree of oxidation graphene oxide is an insulating material. The minimum of total energy is found when the graphene oxide has full coverage. This work can contribute to understand the plasticity and ductility properties of graphene oxide recently reported

The 4G/5G PAI-1 polymorphism influences the endothelial response to IL-1 and the modulatory effect of pravastatin

BACKGROUND: Increased plasminogen activator inhibitor (PAI-1) levels lead to impaired fibrinolytic function associated with higher cardiovascular risk. PAI-1 expression may be regulated by different inflammatory cytokines such as interleukin-1alpha (IL-1). Several polymorphisms have been described in the PAI-1 gene. AIM: We examined the influence of the 4G/5G polymorphism in the promoter region on IL-1alpha-induced PAI-1 expression by human umbilical vein endothelial cells (HUVEC) in presence or absence of pravastatin. METHODS AND RESULTS: Genotyped HUVEC were incubated with IL-1alpha (500 U mL(-1)) in presence or absence of pravastatin (1-10 microm). PAI-1 expression was analyzed by real time polymerase chain reaction (PCR), and PAI-1 antigen measured in supernatants by ELISA. IL-1alpha increased PAI-1 secretion in a genotype-dependent manner, and higher values were observed for 4G/4G compared with both 4G/5G and 5G/5G cultures (P < 0.05). Preincubation of HUVEC with 10 microm pravastatin significantly reduced IL-1-induced PAI-1 expression in 4G/4G HUVEC compared with untreated cultures (177.5% +/- 24.5% vs. 257.9% +/- 39.0%, P < 0.05). Pravastatin also attenuated the amount of secreted PAI-1 by 4G/4G HUVEC after IL-1 stimulation (5020.6 +/- 165.7 ng mL(-1) vs. 4261.1 +/- 309.8 ng mL(-1), P < 0.05). This effect was prevented by coincubation with mevalonate, indicating a dependence on HMG-CoA reductase inhibition. CONCLUSIONS: The endothelial 4G/5G PAI-1 genotype influences the PAI-1 response to IL-1alpha and the modulatory effect of pravastatin. As increased PAI-1 levels have been linked to cardiovascular disease the observed endothelial modulation by pravastatin may have potential clinical implications

Validation of plasma fibrinogen as a marker of carotid atherosclerosis in subjects free of clinical cardiovascular disease

BACKGROUND AND OBJECTIVES: Fibrinogen has been found to be an independent risk factor for cardiovascular disease. The aim of this study was to validate the measurement of plasma fibrinogen as a marker of subclinical atherosclerosis in a series of asymptomatic subjects (n=519, median age 55.5 years, 80% men). DESIGN AND METHODS: All individuals had a complete clinical examination, lipid profile (cholesterol and its high and low density lipoprotein fractions and triglycerides), global vascular risk assessment (PROCAM), and B-mode ultrasonography of the carotid arteries to determine the intima-media thickness (IMT) and the presence of atheroma plaques. C-reactive protein (CRP), and von Willebrand factor (vWF) were also measured in all subjects as markers of inflammation/endothelial damage. RESULTS: In the univariate model, a positive relationship was found between plasma fibrinogen concentration and carotid IMT (p<0.001). Fibrinogen concentration also correlated positively with age (p<0.001), systolic blood pressure (p<0.001), smoking (p<0.05), diabetes (p<0.05), PROCAM (p<0.001), CRP and vWF (p<0.001). In the multivariate analysis, the association of fibrinogen with carotid IMT remained significant (p=0.008) after adjustment for all parameters analyzed. INTERPRETATION AND CONCLUSIONS: In a population sample of adults without clinically overt atherosclerotic disease, elevated fibrinogen levels was related to carotid IMT independently of a wide range of important confounding variables. Plasma fibrinogen may represent a systemic marker of carotid atherosclerosis

Protective effect of the G-765C COX-2 polymorphism on subclinical atherosclerosis and inflammatory markers in asymptomatic subjects with cardiovascular risk factors

BACKGROUND: Cyclooxygenase (COX)-2, a key regulatory enzyme in prostanoid synthesis, plays an important role in inflammatory processes. The -765G>C COX-2 polymorphism has been associated with lower promoter activity in vitro and reduced levels of C-reactive protein (CRP) in atherosclerotic carriers of the C allele. However, its pathophysiological relevance in vivo has not been fully elucidated. METHODS AND RESULTS: We assessed the -765G>C polymorphism and COX-2 expression in 220 asymptomatic subjects free of cardiovascular disease, in relation to global vascular risk, carotid intima-media thickness (IMT), and inflammatory markers (fibrinogen, C-reactive protein [CRP], von Willebrand factor [vWF] and interleukin-6 [IL-6]). Genotype frequencies were: CC (7.7%), CG (34.5%), GG (57.7%). Among hypercholesterolemic subjects (n=140), C allele carriers had lower COX-2 expression (p<0.05), reduced carotid IMT (p<0.01) and diminished levels of inflammatory markers CRP, vWF and IL-6 (p<0.05), as compared to GG homozygous subjects. The association between carotid IMT and COX-2 polymorphism remained significant after adjusting for cardiovascular risk factors and inflammatory markers (p=0.008). CONCLUSIONS: In asymptomatic hypercholesterolemic subjects the C allele of -765G>C COX-2 polymorphism was associated with lower COX-2 expression, and reduced subclinical atherosclerosis and systemic inflammation compared with GG homozygous, thus conferring atherosclerosis protection in this cardiovascular risk population

Antioxidant vitamins increase the collagen content and reduce MMP-1 in a porcine model of atherosclerosis: implications for plaque stabilization

Degradation of extracellular matrix, particularly interstitial collagen, promotes plaque instability and contributes to restenosis after vascular injury. We have explored the effects of vitamins C and E on the collagen content and metalloproteinase-1 (MMP-1) expression after angioplasty in hypercholesterolemic pigs. Iliac angioplasty was performed on 18 minipigs divided into three diet groups: a normal-cholesterol (NC), a high-cholesterol (HC) and a high-cholesterol plus vitamins C+E (HCV). Four weeks later, after sacrifice, the vascular collagen content and MMP-1 protein expression, along with the plasma caseinolytic activity and lipid peroxidation, were measured. MMP-1 was also determined in arterial rings stimulated with native low-density lipoproteins (LDL) isolated from experimental groups. Cholesterol-rich diet augmented plasma lipid peroxidation (P<0.05), reduced the collagen content and increased vascular MMP-1 expression after injury (P<0.05). Enhanced caseinolytic activity (identified as MMP-1) was also observed in HC plasma samples and in supernatants from arterial rings incubated with HC-LDL. Vitamins C and E markedly increased neointimal collagen content (P<0.01), reduced the hypercholesterolemia-induced changes in vascular MMP-1 (P<0.05) and diminished plasma and ex vivo caseinolytic activity. Vitamins C and E may help stabilize atherosclerotic plaque after angioplasty and favor vascular remodeling by increasing collagen content and reducing vascular MMP-1 expression in porcine hypercholesterolemia

Long-Term Ozone Variability and Trends from Reanalyses

Stratospheric ozone has a profound impact on radiation and chemistry over various spatial and temporal scales. The evolution of stratospheric ozone over the 21st century, however, is not well understood, especially in the lower stratosphere. Highly vertically resolved ozone data from satellite-borne limb sounders have proved to be invaluable for studying ozone in the middle and upper stratosphere but it was not until recently that these measurements were successfully incorporated in atmospheric reanalyses. Validation and comparison studies have demonstrated that the addition of observations from the Microwave Limb Sounder (MLS) on EOS (Earth Observing System) Aura greatly improved the quality of ozone fields in MERRA-2 (Modern-Era Retrospective analysis for Research and Applications, Version 2) making these assimilated data sets more useful for scientific research. In this presentation we demonstrate that multidecadal lower-stratospheric ozone variability and trends can be derived from NASA's MERRA-2 reanalysis ozone. In particular, the reanalysis ozone bias-corrected using a chemistry model simulation as a transfer function agrees very well with recently reprocessed long ozonesonde records. Ozone trends in the lower stratosphere will be discussed in the context of recent findings (Ball et al., 2018) and interpreted in connection with long-term circulation changes in the lower stratosphere. Next, we show that the use of ozone data retrieved from the next generation OMPS (Ozone Mapping Profiler Suite) instruments, including the OMPS Limb Profiler, can successfully extend the reanalyses into the future allowing comprehensive monitoring of global ozone and interpretation of its evolution during the critical period of expected ozone recovery and climate change from increasing concentration of greenhouse gases

Different expression of MMPs/TIMP-1 in human atherosclerotic lesions. Relation to plaque features and vascular bed

BACKGROUND: Proteolytic imbalance might determine arterial remodeling and plaque destabilization in atherosclerotic vessels. The aim of this study was to examine differences in the patterns of metalloproteinases (MMPs) and MMP inhibitor (TIMP-1) expression in advanced human atheromas, both in relation to the plaque features and the vascular bed involved. METHODS AND RESULTS: Immunohistochemistry for MMP-1, -3, -9 and TIMP-1 as well as the collagen content were measured in vascular sections from patients undergoing peripheral revascularization (carotid n=11, femoral n=23) and aorto-coronary bypass surgery (mammary arteries n=20, as controls). Increased expression of all MMPs was detected in atherosclerotic as compared with control sections (P<0.01). Aneurysmal plaques showed a significant increase of MMP-1 and-3 and a reduction in total collagen (P<0.05) in relation to occlusive lesions. Calcification areas in atherosclerotic plaques were consistently associated with increased TIMP-1 expression (P<0.01). Finally, MMP-9 expression was higher in occlusive lesions from carotid than femoral arteries (P<0.01). CONCLUSIONS: Aneurysm lesions expressed higher MMP-1 and-3 expression than occlusive plaques, and MMP-9 was mainly detected in carotid as compared with femoral arteries. TIMP-1 was associated with arterial calcification. These differences in the MMPs/TIMP-1 expression might determine the evolution of advanced atherosclerotic plaques and contribute to its vulnerability

Association of sepsis-related mortality with early increase of TIMP-1/MMP-9 ratio

Objective: Higher circulating levels of tissue inhibitor of matrix metalloproteinases (TIMP)-1 at the time of severe sepsis diagnosis have been reported in nonsurviving than in surviving patients. However, the following questions remain unanswered: 1) Does TIMP-1/MMP-9 ratio differ throughout the first week of intensive care between surviving and nonsurviving patients? 2) Is there an association between TIMP-1/MMP-9 ratio and sepsis severity and mortality during such period? 3) Could TIMP-1/MMP-9 ratio during the first week be used as an early biomarker of sepsis outcome? 4) Is there an association between TIMP-1/MMP-9 ratio and coagulation state and circulating cytokine levels during the first week of intensive care in these patients? The present study sought to answer these questions. Methods: Multicenter, observational and prospective study carried out in six Spanish Intensive Care Units (ICUs) of 295 patients with severe sepsis. Were measured circulating levels of TIMP-1, MMP-9, tumour necrosis factor (TNF)-alpha, interleukin (IL)-10 and plasminogen activator inhibitor (PAI)-1 at day 1, 4 and 8. End-point was 30-day mortality. Results: We found higher TIMP-1/MMP-9 ratio during the first week in non-surviving (n = 98) than in surviving patients (n = 197) (p, 0.01). Logistic regression analyses showed that TIMP-1/MMP-9 ratio at days 1, 4 and 8 was associated with mortality. Receiver operating characteristic (ROC) curves showed that TIMP-1/MMP-9 ratio at days 1, 4 and 8 could predict mortality. There was an association between TIMP-1/MMP-9 ratio and TNF-alpha, IL-10, PAI-1 and lactic acid levels, SOFA score and platelet count at days 1, 4 and 8. Conclusions: The novel findings of our study were that non-surviving septic patients showed persistently higher TIMP-1/ MMP-9 ratio than survivors ones during the first week, which was associated with severity, coagulation state, circulating cytokine levels and mortality; thus representing a new biomarker of sepsis outcome