Evidence of Uncoupling between Renal Dysfunction and Injury in Cardiorenal Syndrome: Insights from the BIONICS Study

Objective

The objective of the study was to assess urinary biomarkers of renal injury for their individual or collective ability to predict Worsening renal function (WRF) in patients with acutely decompensated heart failure (ADHF).

Methods

In a prospective, blinded international study, 87 emergency department (ED) patients with ADHF were evaluated with biomarkers of cardiac stretch (B type natriuretic peptide [BNP] and its amino terminal equivalent [NT-proBNP], ST2), biomarkers of renal function (creatinine, estimated glomerular filtration rate [eGFR]) and biomarkers of renal injury (plasma neutrophil gelatinase associated lipocalin [pNGAL], urine kidney injury molecule-1 [KIM-1], urine N-acetyl-beta-D-glucosaminidase [NAG], urine Cystatin C, urine fibrinogen). The primary endpoint was WRF.

Results

26% developed WRF; baseline characteristics of subjects who developed WRF were generally comparable to those who did not. Biomarkers of renal function and urine biomarkers of renal injury were not correlated, while urine biomarkers of renal injury correlated between each other. Biomarker concentrations were similar between patients with and without WRF except for baseline BNP. Although plasma NGAL was associated with the combined endpoint, none of the biomarker showed predictive accuracy for WRF.

Conclusions

In ED patients with ADHF, urine biomarkers of renal injury did not predict WRF. Our data suggest that a weak association exists between renal dysfunction and renal injury in this setting (Clinicaltrials.gov NCT#0150153).     

GAL4-GFP enhancer trap lines for genetic manipulation of lateral root development in Arabidopsis thaliana

Lateral root development occurs throughout the life of the plant and is responsible for the plasticity of the root system. In Arabidopsis thaliana, lateral root founder cells originate from pericycle cells adjacent to xylem poles. In order to study the mechanisms of lateral root development, a population of Arabidopsis GAL4-GFP enhancer trap lines were screened and two lines were isolated with GAL4 expression in root xylem-pole pericycle cells (J0121), i.e. in cells competent to become lateral root founder cells, and in young lateral root primordia (J0192). These two enhancer trap lines are very useful tools with which to study the molecular and cellular bases of lateral root development using targeted gene expression. These lines were used for genetic ablation experiments by targeting the expression of a toxin-encoding gene. Moreover, the molecular bases of the enhancer trap expression pattern were characterized. These results suggest that the lateral-root-specific GAL4 expression pattern in J0192 is due to a strong enhancer in the promoter of the LOB-domain protein gene LBD16.     

Validation of improved recording site to measure phrenic conduction from surface electrodes in humans.

Phrenic nerve stimulation, electrical (ES) or from cervical magnetic stimulation (CMS), allows one to assess the diaphragm contractile properties and the conduction time of the phrenic nerve (PNCT) through recording of an electromyographic response, traditionally by using surface electrodes. Because of the coactivation of extradiaphragmatic muscles, signal contamination can jeopardize the determination of surface PNCTs. To address this, we compared PNCTs with ES and CMS from surface and needle diaphragm electrodes in five subjects (10 phrenic nerves). At a modified recording site, lower and more anterior than usual (lowest accessible intercostal space, costochondral junction) with electrodes 2 cm apart, surface and needle PNCTs were similar (CMS: 6.0 +/- 0.25 ms surface vs. 6.2 +/- 0.13 ms needle, not significant). Electrodes recording the activity of the most likely sources of signal contamination, i.e., the serratus anterior and pectoralis major, showed distinct responses from that of the diaphragm, their earlier occurrence strongly arguing against contamination. With ES and CMS, apparently uncontaminated signals could be consistently recorded from surface electrodes.     

The isthmic organizer links anteroposterior and dorsoventral patterning in the mid/hindbrain by generating roof plate structures

During vertebrate development, an organizing signaling center, the isthmic organizer, forms at the boundary between the midbrain and hindbrain. This organizer locally controls growth and patterning along the anteroposterior axis of the neural tube. On the basis of transplantation and ablation experiments in avian embryos, we show here that, in the caudal midbrain, a restricted dorsal domain of the isthmic organizer, that we call the isthmic node, is both necessary and sufficient for the formation and positioning of the roof plate, a signaling structure that marks the dorsal midline of the neural tube and that is involved in its dorsoventral patterning. This is unexpected because in other regions of the neural tube, the roof plate has been shown to form at the site of neural fold fusion, which is under the influence of epidermal ectoderm derived signals. In addition, the isthmic node contributes cells to both the midbrain and hindbrain roof plates, which are separated by a boundary that limits cell movements. We also provide evidence that mid/hindbrain roof plate formation involves homeogenetic mechanisms. Our observations indicate that the isthmic organizer orchestrates patterning along the anteroposterior and the dorsoventral axis.     

Geographic distribution and host plants of Raoiella indica and associated mite species in northern Venezuela

The red palm mite (RPM), Raoiella indica Hirst (Acari: Tenuipalpidae), is an invasive pest in the New World, where it is currently considered a serious threat to coconut and banana crops. It was first reported from northern Venezuela in 2007. To determine its current distribution in this country, surveys were carried out from October 2008 to April 2010 on coconut (Cocos nucifera L.), banana (Musa spp.), ornamental plants and weeds in northern Venezuela. Higher population levels of RPM were registered on commercial coconut farms in Falcón and Sucre states but also on other plant species naturally growing along the coastal line in Anzoategui, Aragua, Carabobo, Monagas and Nueva Esparta states. Out of 34 botanical species evaluated, all RPM stages were observed only on eight arecaceous, one musaceous and one streliziaceous species, indicating that the pest developed and reproduced only on these plants. Mite specimens found on weeds were considered spurious events, as immature stages of the pest were never found on these. Amblyseius largoensis (Muma) (Acari: Phytoseiidae) was the most frequent predatory mite associated with RPM in all sampling sites. The results indicate that RPM has spread to extensive areas of northern Venezuela since its initial detection in Güiria, Sucre state. Considering the report of this pest mite in northern Brazil in the late 2009, additional samplings in southern Venezuela should be carried out, to evaluate the possible presence of RPM also in that region.     

Development of a homogeneous time-resolved fluorescence leukotriene B4 assay for determining the activity of leukotriene A4 hydrolase

Leukotriene A4 (LTA4) hydrolase catalyzes a rate-limiting final biosynthetic step of leukotriene B4 (LTB4), a potent lipid chemotactic agent and proinflammatory mediator. LTB4 has been implicated in the pathogenesis of various acute and chronic inflammatory diseases, and thus LTA4 hydrolase is regarded as an attractive therapeutic target for anti-inflammation. To facilitate identification and optimization of LTA4 hydrolase inhibitors, a specific and efficient assay to quantify LTB4 is essential. This article describes the development of a novel 384-well homogeneous time-resolved fluorescence assay for LTB4 (LTB4 HTRF assay) and its application to establish an HTRF-based LTA4 hydrolase assay for lead optimization. This LTB4 HTRF assay is based on competitive inhibition and was established by optimizing the reagent concentration, buffer composition, incubation time, and assay miniaturization. The optimized assay is sensitive, selective, and robust, with a Z' factor of 0.89 and a subnanomolar detection limit for LTB4. By coupling this LTB4 HTRF assay to the LTA4 hydrolase reaction, an HTRF-based LTA4 hydrolase assay was established and validated. Using a test set of 16 LTA4 hydrolase inhibitors, a good correlation was found between the IC50 values obtained using LTB4 HTRF with those determined using the LTB enzyme-linked immunoassay (R = 0.84). The HTRF-based LTA4 hydrolase assay was shown to be an efficient and suitable assay for determining compound potency and library screening to guide the development of potent inhibitors of LTA4 hydrolase.     

COMMD1-mediated ubiquitination regulates CFTR trafficking

The CFTR (cystic fibrosis transmembrane conductance regulator) protein is a large polytopic protein whose biogenesis is inefficient. To better understand the regulation of CFTR processing and trafficking, we conducted a genetic screen that identified COMMD1 as a new CFTR partner. COMMD1 is a protein associated with multiple cellular pathways, including the regulation of hepatic copper excretion, sodium uptake through interaction with ENaC (epithelial sodium channel) and NF-kappaB signaling. In this study, we show that COMMD1 interacts with CFTR in cells expressing both proteins endogenously. This interaction promotes CFTR cell surface expression as assessed by biotinylation experiments in heterologously expressing cells through regulation of CFTR ubiquitination. In summary, our data demonstrate that CFTR is protected from ubiquitination by COMMD1, which sustains CFTR expression at the plasma membrane. Thus, increasing COMMD1 expression may provide an approach to simultaneously inhibit ENaC absorption and enhance CFTR trafficking, two major issues in cystic fibrosis.     

Cellulase immobilization on magnetic nanoparticles encapsulated in polymer nanospheres

Immobilization of cellulases on magnetic nanoparticles, especially magnetite nanoparticles, has been the main approach studied to make this enzyme, economically and industrially, more attractive. However, magnetite nanoparticles tend to agglomerate, are very reactive and easily oxidized in air, which has strong impact on their useful life. Thus, it is very important to provide proper surface coating to avoid the mentioned problems. This study aimed to investigate the immobilization of cellulase on magnetic nanoparticles encapsulated in polymeric nanospheres. The support was characterized in terms of morphology, average diameter, magnetic behavior and thermal decomposition analyses. The polymer nanospheres containing encapsulated magnetic nanoparticles showed superparamagnetic behavior and intensity average diameter about 150 nm. Immobilized cellulase exhibited broader temperature stability than in the free form and great reusability capacity, 69% of the initial enzyme activity was maintained after eight cycles of use. The magnetic support showed potential for cellulase immobilization and allowed fast and easy biocatalyst recovery through a single magnet.