Dilution of non-reactive tracers in variably saturated sandy structures

Based on a dye tracer experiment in a sand tank we addressed the problem of local dispersion of conservative tracers in the unsaturated zone. The sand bedding was designed to have a defined spatial heterogeneity with a strong anisotropy. We estimated the parameters that characterize the local dispersion and dilution from concentration maps of a high spatial and temporal resolution obtained by image analysis. The plume spreading and mixing behavior was quantified on the basis of the coefficient of variation of the concentration and of the dilution index. The heterogeneous structure modified the flow pattern depending on water saturation. The shape of the tracer plumes revealed the structural signature of the sand bedding at low saturation only. In this case pronounced preferential flow was observed. At higher flow rates the structure remained hidden by a spatially almost homogeneous behavior of the plumes. In this context, we mainly discuss the mechanism of re-distributing a finite mass of inert solutes over a large volume, due to macro- and micro-heterogeneities of the structure. (C) 2001 Elsevier Science Ltd. AU rights reserved.

The lectin-like domain of tumor necrosis factor improves lung function after rat lung transplantation--potential role for a reduction in reactive oxygen species generation

To test the hypothesis that the lectin-like domain of tumor necrosis factor, mimicked by the TIP peptide, can improve lung function after unilateral orthotopic lung isotransplantation. Because of a lack of a specific treatment for ischemia reperfusion-mediated lung injury, accompanied by a disrupted barrier integrity and a dysfunctional alveolar liquid clearance, alternative therapies restoring these parameters after lung transplantation are required.

Postoperative serum pro-calcitonin and C-reactive protein levels in patients with orthopedic infections

QUESTIONS UNDER STUDY / PRINCIPLES: The value of postoperative pro-calcitonin (PCT) in the follow-up of patients with localised infections in the orthopaedic domain is unknown.

Reactive oxygen species mediate functional differences in human radial and internal thoracic arteries from smokers

Smoking not only increases the risk that coronary heart disease will develop but also morbidity and mortality in patients with known coronary atherosclerosis and after coronary artery bypass grafting. Excessive generation of reactive oxygen species (ROS) has been implicated as the final common pathway for the development of endothelial dysfunction in various cardiovascular risk factors. This study assessed the influence of smoking on two different human arteries routinely used as coronary artery bypass graft conduits.

Loss of sphingosine kinase-1 in carcinoma cells increases formation of reactive oxygen species and sensitivity to doxorubicin-induced DNA damage

Sphingosine kinases (SK) catalyse the formation of sphingosine 1-phosphate, which is a key lipid mediator regulating cell responses such as proliferation, survival and migration. Here we have investigated the effect of targeted inhibition of SK-1 on cell damage and elucidated the mechanisms involved.

Associations of Reactive Hyperemia Index and Intravascular Ultrasound-Assessed Coronary Plaque Morphology in Patients With Coronary Artery Disease

Although reactive hyperemia index (RHI) predicts future coronary events, associations with intravascular ultrasound (IVUS)-assessed coronary plaque structure have not been reported. This study therefore investigated associations between RHI and IVUS-assessed coronary plaques. In 362 patients RHI was measured by noninvasive peripheral arterial tonometry and coronary plaque components (fibrous, fibrofatty, necrotic core, and dense calcium) were identified by IVUS in 594 vessel segments of the left anterior descending, circumflex, and/or right coronary arteries. RHI values <1.67 were considered abnormal. Analysis of variance was used to detect independent associations between RHI and plaque composition. Patients with an abnormal RHI had greater plaque burden (41% vs 39% in patients with normal RHI, p = 0.047). Compared to patients with normal RHI, plaque of patients with abnormal RHI had more necrotic core (21% vs 17%, p <0.001) and dense calcium (19% vs 15%, p <0.001) and less fibrous (49% vs 54%, p <0.001) and fibrofatty (11% vs 14%, p = 0.002) tissue. After adjustment for age, gender, cardiovascular risk factors, and drug therapy, abnormal RHI remained significantly associated with fibrous (F ratio 14.79, p <0.001), fibrofatty (F ratio 5.66, p = 0.018), necrotic core (F ratio 14.47, p <0.001), and dense calcium (F ratio 10.80, p = 0.001) volumes. In conclusion, coronary artery plaques of patients with abnormal RHI had a larger proportion of necrotic core and dense calcium. The association of an abnormal RHI with a plaque structure that is more prone to rupture may explain why these patients exhibit a greater risk of coronary events.

Effect of Alzheimer Caregiving on Circulating Levels of C-Reactive Protein and Other Biomarkers Relevant to Cardiovascular Disease Risk: A Longitudinal Study

Providing care to a spouse with Alzheimer's disease (AD) may contribute to cardiovascular disease (CVD). The acute phase reactant C-reactive protein (CRP) is a well-established biomarker of an increased CVD risk.

Quantification of oxidized levels of specific RNA species using an aldehyde reactive probe

Emerging evidence has shown that oxidation of RNA, including messenger RNA (mRNA), is elevated in several age-related diseases, although investigation of oxidized levels of individual RNA species has been limited. Recently we reported that an aldehyde reactive probe (ARP) quantitatively reacts with oxidatively modified depurinated/depyrimidinated (abasic) RNA. Here we report a novel method to isolate oxidized RNA using ARP and streptavidin beads. An oligo RNA containing abasic sites that were derivatized with ARP was pulled down by streptavidin beads, whereas a control oligo RNA was not. In vitro oxidized RNA, as well as total cellular RNA, isolated from oxidatively stressed cells was also pulled down, dependent on oxidation level, and concentrated in the pull-down fraction. Quantitative reverse transcription polymerase chain reaction (RT-PCR) using RNA in the pull-down fraction demonstrated that several gene transcripts were uniquely increased in the fraction by oxidative stress. Thus, our method selectively concentrates oxidized RNA by pull-down and enables the assessment of oxidation levels of individual RNA species. (C) 2011 Elsevier Inc. All rights reserved.