A brief comparative study of four disposable bubble oxygenators

Four widely used bubble oxygenators-the Optiflo I, the Bentley Q 200 A, the Harvey 200, and the Shiley 100 A-were tested and compared in 182 patients undergoing cardiac valve surgery. Fifty-six cases were performed with normothermia and 126 cases incorporated mild hypothermia (28-30 degrees C). There was no significant difference in the average age of the patients (51 yrs) or the perfusion time (60 min). All components of the extracorporeal circuit were identical, and anesthetic regimens and surgical techniques were also similar. In this study, the Shiley 100 A oxygenator was found to be the most suitable for cases requiring mild hypothermia and was generally considered to be the oxygenator of choice.     

MyROOT: a method and software for the semiautomatic measurement of primary root length in Arabidopsis seedlings

Root analysis is essential for both academic and agricultural research. Despite the great advances in root phenotyping and imaging, calculating root length is still performed manually and involves considerable amounts of labor and time. To overcome these limitations, we developed MyROOT, a software for the semiautomatic quantification of root growth of seedlings growing directly on agar plates. Our method automatically determines the scale from the image of the plate, and subsequently measures the root length of the individual plants. To this aim, MyROOT combines a bottom‐up root tracking approach with a hypocotyl detection algorithm. At the same time as providing accurate root measurements, MyROOT also significantly minimizes the user intervention required during the process. Using Arabidopsis, we tested MyROOT with seedlings from different growth stages and experimental conditions. When comparing the data obtained from this software with that of manual root measurements, we found a high correlation between both methods (R² = 0.997). When compared with previous developed software with similar features (BRAT and EZ‐Rhizo), MyROOT offered an improved accuracy for root length measurements. Therefore, MyROOT will be of great use to the plant science community by permitting high‐throughput root length measurements while saving both labor and time.     

Synthesis and inotropic activity of hydroindene derivatives

A synthetic approach to hydroindenic inotropic agents has been developed, starting from enantiopure Hajos-Parrish (1). Hajos-Wiechert (2), and related diketones. Their transformation into C-1 formyl derivatives and other subsequent synthetic targets is described. The results of the thermodynamic equilibration between both epimers of each formyl derivative are analysed. The inotropic activities of selected compounds on right and left atrial preparations are also evaluated and discussed.     

Heterogeneous distribution of plasma membrane glycoconjugates in pancreatic acinar cells

Flow-cytometric studies of lectin binding to individual acinar cells have been carried out in order to analyse the distribution of membrane glycoconjugates in cells from different areas of the pancreas: duodenal lobule (head) and splenic lobule (body and tail). The following fluoresceinated lectins were used: wheat germ agglutinin (WGA), Tetragonolobus purpureus agglutinin (TP) and concanavalin A (Con A), which specifically bind to N-acetyl D-glucosamine and sialic acid, L-fucose and D-mannose, respectively. In both pancreatic areas, two cell populations (R1 and R2) were identified according to the forward scatter (size). On the basis of their glycoconjugate pattern, R1 cells displayed higher density of WGA and TP receptors than R2 cells throughout the pancreas. Although no difference in size was found between the cells from duodenal and splenic lobules, N-acetyl D-glucosamine and/or sialic acid and L-fucose residues were more abundant in plasma membrane cell glycoconjugates from the duodenal lobule. The results provide evidence for biochemical heterogeneity among individual pancreatic cells according to the distribution of plasma membrane glycoconjugates.     

SimArray: a user-friendly and user-configurable microarray design tool

Background  

Microarrays were first developed to assess gene expression but are now also used to map protein-binding sites and to assess allelic variation between individuals. Regardless of the intended application, efficient production and appropriate array design are key determinants of experimental success. Inefficient production can make larger-scale studies prohibitively expensive, whereas poor array design makes normalisation and data analysis problematic.     

High protein binding and cidal activity against penicillin-resistant S. pneumoniae: a cefditoren in vitro pharmacodynamic simulation

Background

Although protein binding is a reversible phenomenon, it is assumed that antibacterial activity is exclusively exerted by the free (unbound) fraction of antibiotics.

Methodology/Principal Findings

Activity of cefditoren, a highly protein bound 3^rd generation cephalosporin, over 24h after an oral 400 mg cefditoren-pivoxil bid regimen was studied against six S. pneumoniae strains (penicillin/cefditoren MICs; µg/ml): S1 (0.12/0.25), S2 (0.25/0.25), S3 and S4 (0.5/0.5), S5 (1/0.5) and S6 (4/0.5). A computerized pharmacodynamic simulation with media consisting in 75% human serum and 25% broth (mean albumin concentrations = 4.85±0.12 g/dL) was performed. Protein binding was measured. The cumulative percentage of a 24h-period that drug concentrations exceeded the MIC for total (T>MIC) and unbound concentrations (fT>MIC), expressed as percentage of the dosing interval, were determined. Protein binding was 87.1%. Bactericidal activity (≥99.9% initial inocula reduction) was obtained against strains S1 and S2 at 24h (T>MIC = 77.6%, fT>MIC = 23.7%). With T>MIC of 61.6% (fT>MIC = 1.7%), reductions against S3 and S4 ranged from 90% to 97% at 12h and 24h; against S5, reduction was 45.1% at 12h and up to 85.0% at 24h; and against S6, reduction was 91.8% at 12h, but due to regrowth of 52.9% at 24h. Cefditoren physiological concentrations exerted antibacterial activity against strains exhibiting MICs of 0.25 and 0.5 µg/ml under protein binding conditions similar to those in humans.

Conclusions/Significance

The results of this study suggest that, from the pharmacodynamic perspective, the presence of physiological albumin concentrations may not preclude antipneumococcal activity of highly bound cephalosporins as cefditoren.     

Internalization of the receptor for advanced glycation end products (RAGE) is required to mediate intracellular responses

To dissect the rat receptor for advanced glycation end products (RAGE) subcellular distribution and trafficking in eukaryotic cells, an expression system coding for a fusion protein between the RAGE and an enhanced green fluorescent protein (EGFP) has been used. The RAGE-EGFP protein is expressed at the plasma membrane of CHO-k1 and Neuro-2a (N2a) cells and retains the capacity to bind Texas Red-labelled advanced glycation end products (AGEs). AGEs addition to the cell cultures induced a change in the subcellular distribution of the fluorescent RAGE-EGFP protein compatible with an internalization of the AGEs-RAGE complex. Furthermore, while N2a cells expressing the RAGE-EGFP showed an increase in ERK1/2 phosphorylation and NF-kappaB DNA binding in response to AGEs, pre-incubation with dansyl-cadaverine or phenylarsine oxide, inhibitors of receptors internalization, blocked the activation of ERKs and other intracellular responses mediated by AGEs. These results suggest that internalization plays a key role in the signal transduction mediated by RAGE.     

Differential seedling regeneration patterns across forest–grassland ecotones in two tropical treeline species (Polylepis spp.)

Successful forest expansion into grassland can be limited by seed dispersal and adverse conditions for tree seedlings in the grassland environment. In the high‐elevation Andes, human‐induced fragmentation has exacerbated the patchy distribution of Polylepis forests, threatening their unique biological communities and spurring restoration interest. Studies of Polylepis forest extent in Peru suggest that forest borders have remained stable over the past century despite decreasing anthropogenic disturbance, suggesting that tree seedling recruitment is being limited in the open grassland habitat. We studied natural seedling dispersion patterns of Polylepis sericea and Polylepis weberbaueri (Rosaceae) at forest–grassland edges across a range of environmental conditions to examine seedling recruitment and colonization of grasslands in Huascaran National Park (Peru). Using data from 2367 seedlings found in 48 forest–grassland edge plots (15 m × 15 m) at forest patches between 3900–4500 masl, we employed generalized mixed modelling to identify the significant associations of seedling densities with environmental covariates. In addition, we compared these associations to patterns of adult presence on the landscape. Seedling densities were associated with a combination of variables varying within (distance to forest edge) and among (elevation and dry season solar irradiation) plots across the landscape. For both species, seedling densities decreased with increasing distance away from the forest in a manner consistent with short‐distance seed dispersal by wind. Our results suggest that such short‐distance dispersal may slow forest expansion, but that there also appear to be substantial post‐dispersal limitations to seedling establishment in the grassland. Polylepis sericea densities decreased with elevation, while P. weberbaueri increased with elevation and decreased with solar irradiation. Associations of adult presence with elevation and solar irradiation mirrored those of seedling densities. Management of areas with forest patches dominated by these species should consider these differences in their environmental tolerances, particularly during species selection and zonation for reforestation.