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The aim of this study was to evaluate the appearance, extent, and distribution of parenchymal changes in the lung after acute respiratory distress syndrome (ARDS) as a function of disease severity and therapeutic procedures. High-resolution computed tomography (HRCT), clinical examination, and lung function tests were performed in 15 patients, 6-10 months after ARDS. The appearance and extent of parenchymal changes were compared with the severity of ARDS, as well as with clinical and therapeutic data. Lung parenchymal changes resembling those found in the presence of pulmonary fibrosis were observed in 13 of 15 patients (87%). The changes were significantly more frequent and more pronounced in the ventral than in the dorsal portions of the lung ( p<0.01). A significant correlation was observed between the extent of lung alterations and the severity of ARDS ( p<0.01), and the duration in which patients had received mechanical ventilation either with a peak inspiratory pressure greater than 30 mmHg ( p<0.05), or with more than 70% oxygen ( p<0.01). Acute respiratory distress syndrome frequently is followed by fibrotic changes in lung parenchyma. The predominantly ventral distribution of these changes indicates that they may be caused by the ventilation regimen and the oxygen therapy rather than by the ARDS. [ABSTRACT FROM AUTHOR]

Background: Acute renal failure (ARF) can be triggered or aggravated by reactive oxygen species (ROS) but established ARF per se might also affect the antioxidant defence mechanisms of the organism. We evaluated a broad pattern of antioxidants in critically ill patients with multiple organ failure with (MOF-ARF) and without acute renal failure (MOF) to identify any potential involvement of renal dysfunction in the depletion of the antioxidant system.Methods: Observational study; 13 patients with MOF were investigated (9 with and 4 without ARF), and 17 healthy subjects served as controls. Blood samples were drawn after establishment of MOF. Plasma levels of ascorbate, alpha-tocopherol, retinol, beta-carotene, selenium and lipid peroxidation products (MDA) were determined and the activities of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione-peroxidase (GSH-PX) in erythrocytes were measured. In addition, ROS production (superoxide anion and hydrogen peroxide) in activated neutrophils was assessed.Results: Plasma levels of ascorbate, beta-carotene and selenium were reduced in both patient groups, when compared to controls. Decrease in selenium was more pronounced in the MOF-ARF group. MDA levels were increased in both groups, again being more pronounced in MOF-ARF patients compared to MOF patients. Hydrogen peroxide production by neutrophils from both patient groups was lower than from controls.Conclusion: A depression of the antioxidative system is present in critically ill patients with MOF. In patients with associated ARF this was even more pronounced and plasma MDA levels were higher, suggesting an additional effect on the antioxidative potential in the presence of renal dysfunction and/or renal replacement therapy. [ABSTRACT FROM AUTHOR]

Background: Mechanical hyperventilation is an established treatment to reduce brain edema and intracranial pressure in patients with encephalopathia caused by acute liver failure. Hyperventilation and ensuing hypocarbia may also affect central and systemic circulation and thereby influence graft performance in patients following orthotopic liver transplantation (OLT).Methods: We measured the effects of normocapnia and hypocapnia on systemic hemodynamics, gastric tonometry, as a marker of splanchnic oxygenation, and the indocyanine green kinetic, as a global marker of graft function, in humans post OLT.Results: Hyperventilation was performed to a PaCO2 of 4.2 +/- 0.4 kPa (31 +/- 3.4 mm Hg) for about 1 h in 14 liver transplant recipients. Systemic hemodynamics as well as indices of splanchnic oxygenation and indocyanine green kinetics remained statistically unchanged.Conclusion: We did not observe any statistically significant circulatory effects or changes in indocyanine green kinetics in liver transplant recipients in the immediate OLT postoperative period caused by short-term mechanical hyperventilation. [ABSTRACT FROM AUTHOR]

Increasing deposition of anthropogenic N may detrimentally impact terrestrial and aquatic ecosystems. Research on the impacts of Ndeposition has focused primarily on regions with rates greater than 10 kg N ha-1 yr-1, yet lower rates may substantially impact ecosystems with lower biological capacity to sequester the additional inputs of N. Alpine tundra, due to low rates of primaryproduction and soil microbial activity, is susceptible to biotic impacts resulting from high N deposition. Increases in N availability in alpine tundra of the southern Rocky Mountains, which is experiencing elevated rates of N deposition from anthropogenic sources (8-10 kg N ha-1 yr-1), will lead to changes in plant species composition as a result of competitive displacement. Such changes in plant community structure will have positivefeedbacks to rates of N cycling. In moist meadow communities, replacement of the dominant Acomastylis rossii by Deschampsia caespitosa will lead to an eightfold increase in net N mineralization and nitrification rates, which in turn will increase groundwater loss of NO3- to aquatic ecosystems. [ABSTRACT FROM AUTHOR]