ABCC1 Is Related to the Protection of the Distal Nephron against Hyperosmolality and High Sodium Environment: Possible Implications for Cancer Chemotherapy

Aims

Glutathione (GSH) plays an important role in protecting cells against oxidative damage. ABCC1 protein transports GSH. Although this protein is largely studied in cancer, due to multidrug resistance phenotype, its role in the tubular cells of the kidney is unknown. The goal of this study was to find out whether ABCC1 has a role in protecting cells from the distal nephron against the stress caused by high medullar osmolality.

Main Methods

MA104 cells were treated with high concentrations of sodium chloride, urea, or both to raise the osmolality of the culture medium. Cell viability was accessed by MTT and trypan blue assays. ABCC1 expression and extrusion of carboxi-fluorescein (CF), a fluorescent ABCC1 substrate, were measured by flow cytometry.

Key Findings

Incubation of MA104 cells in a high sodium concentration medium resulted in changes in cell granularity and altered expression and activity of ABCC1. Urea did not alter ABCC1 expression or activity, but reversed the observed NaCl effects. High sodium concentrations also had a negative effect on cell viability and urea also protected cells against this effect.

Significance

Our findings demonstrate that ABCC1 plays a significant role in the protection of kidney epithelial cells against the stress caused by high sodium environment present in renal medulla.     

Genome-wide association mapping of sexual incompatibility genes in cacao (<Emphasis Type="Italic">Theobroma cacao</Emphasis> L.)

Sexual compatibility limits the production of cacao plantations, being an important selection criterion in breeding programs. However, the current method for characterizing compatibility, based on the frequency of flower setting after controlled pollination, is time consuming, requiring a long time to identify self-compatible individuals. The identification of molecular markers in genomic regions can be an alternative to allow early selection of self-compatible plants. The present study aimed to identify SNP markers associated with sexual compatibility in cacao, by utilizing genome-wide association (GWAS) mapping. A population of 295 individuals mostly from third-generation breeding populations, but also founder clones, was used. This population was phenotypically characterized by hand pollinating 8199 flowers and evaluating the flower retention 15 days after pollination. In addition, leaf samples of each individual were collected and DNA extracted for genotyping by sequencing, generating 5301 SNP markers after cleaning. Genome-wide association mapping analysis was performed using Synbreed, GCTA, and TASSEL softwares. Significant markers associated to incompatibility, likely in strong linkage disequilibrium, were found within a region of 196 kb, in the proximal end of chromosome 4, suggesting the existence of a major gene in that region. However, this result should be validated in a larger population, considering that only 295 trees were used here. When the SNP effects were treated as random in the estimation process, many other regions in the genome appears to be involved with sexual incompatibility in cacao. Candidate genes were found not only in the proximal end of chromosome 4 but also spread in several other regions of the genome.     

Epidemiology and Microbiologic Characterization of Nosocomial Candidemia from a Brazilian National Surveillance Program

Candidemia is a growing problem in hospitals all over the world. Despite advances in the medical support of critically ill patients, candidiasis leads to prolonged hospitalization, and has a crude mortality rate around 50%. We conducted a multicenter surveillance study in 16 hospitals distributed across five regions of Brazil to assess the incidence, species distribution, antifungal susceptibility, and risk factors for bloodstream infections due to Candida species. From June 2007 to March 2010, we studied a total of 2,563 nosocomial bloodstream infection (nBSI) episodes. Candida spp. was the 7^th most prevalent agent. Most of the patients were male, with a median age of 56 years. A total of 64 patients (46.7%) were in the ICU when candidemia occurred. Malignancies were the most common underlying condition (32%). The crude mortality rate of candidemia during the hospital admission was 72.2%. Non-albicans species of Candida accounted for 65.7% of the 137 yeast isolates. C. albicans (34.3%), Candida parapsilosis (24.1%), Candida tropicalis (15.3%) and Candida glabrata (10.2%) were the most prevalent species. Only 47 out of 137 Candida isolates were sent to the reference laboratory for antifungal susceptibility testing. All C. albicans, C. tropicalis and C. parapsilosis isolates were susceptible to the 5 antifungal drugs tested. Among 11 C. glabrata isolates, 36% were resistant to fluconazole, and 64% SDD. All of them were susceptible to anidulafungin and amphotericin B. We observed that C. glabrata is emerging as a major player among non-albicans Candida spp. and fluconazole resistance was primarily confined to C. glabrata and C. krusei strains. Candida resistance to echinocandins and amphotericin B remains rare in Brazil.Mortality rates remain increasingly higher than that observed in the Northern Hemisphere countries, emphasizing the need for improving local practices of clinical management of candidemia, including early diagnosis, source control and precise antifungal therapy.     

Constraining OCT with Knowledge of Device Design Enables High Accuracy Hemodynamic Assessment of Endovascular Implants

Background

Stacking cross-sectional intravascular images permits three-dimensional rendering of endovascular implants, yet introduces between-frame uncertainties that limit characterization of device placement and the hemodynamic microenvironment. In a porcine coronary stent model, we demonstrate enhanced OCT reconstruction with preservation of between-frame features through fusion with angiography and a priori knowledge of stent design.

Methods and Results

Strut positions were extracted from sequential OCT frames. Reconstruction with standard interpolation generated discontinuous stent structures. By computationally constraining interpolation to known stent skeletons fitted to 3D ‘clouds’ of OCT-Angio-derived struts, implant anatomy was resolved, accurately rendering features from implant diameter and curvature (n = 1 vessels, r² = 0.91, 0.90, respectively) to individual strut-wall configurations (average displacement error ~15 μm). This framework facilitated hemodynamic simulation (n = 1 vessel), showing the critical importance of accurate anatomic rendering in characterizing both quantitative and basic qualitative flow patterns. Discontinuities with standard approaches systematically introduced noise and bias, poorly capturing regional flow effects. In contrast, the enhanced method preserved multi-scale (local strut to regional stent) flow interactions, demonstrating the impact of regional contexts in defining the hemodynamic consequence of local deployment errors.

Conclusion

Fusion of planar angiography and knowledge of device design permits enhanced OCT image analysis of in situ tissue-device interactions. Given emerging interests in simulation-derived hemodynamic assessment as surrogate measures of biological risk, such fused modalities offer a new window into patient-specific implant environments.     

Land use,fallow period and the recovery of a Caatinga forest

Caatinga vegetation continues to be converted into mosaics of secondary forest stands, but the affect of this process on biodiversity has not yet been examined. We used 35 regenerating and old‐growth stands of Caatinga to examine the recovery of plant assemblages subsequent to slash‐and‐burn agriculture and cattle ranching/pasture in northeastern Brazil. Plant assemblages were contrasted in terms of community structure (stem density/basal area/species richness/diversity), functional (leaf habit/reproductive traits) and taxonomic composition. Soil attributes were also examined to infer potential drivers for cross‐habitat differences. As expected, plant assemblages clearly differed across a large set of community‐level attributes, including all trait categories relative to leaf habit and reproduction (pollination syndrome/floral color, size, type). Overall, old‐growth forest stands supported distinct and more diverse assemblages at the plot and habitat level; e.g., long‐lived tree species were almost exclusively found in old‐growth forest stands. For most attributes, plant assemblages subsequent to pasture exhibited intermediate values between those exhibited by old‐growth forest and those of agriculture‐related stands. Surprisingly, soils exhibited similar fertility‐related scores across habitats. Our results indicate that: (1) sprouting/resprouting represents an important mechanism of forest regeneration; (2) assemblage‐level attributes suggest recovery at distinct rates; (3) forest regeneration implies community‐level changes in both vegetative and reproductive functional attributes, including directional changes; (4) Caatinga is not able to completely recover in a period of 15‐yr following land abandonment; and (5) historical land use affects recovery rates and successional pathways/taxonomic trajectories. Seasonally dry tropical forests may intrinsically cover a wide range of patterns relative to successional model, recovery rates and successional pathways.     

Genetic analyses of Per.C6 cell clones producing a therapeutic monoclonal antibody regarding productivity and long-term stability

Genetic characterization of protein-producing clones represents additional value to cell line development. In the present study, ten Per.C6 clones producing a Rebmab100 monoclonal antibody were selected using two cloning methods: six clones originated from limiting dilution cloning and four by the automated colony picker ClonePix FL. A stability program was performed for 50 generations, including 4 batches distributed along the timeframe to determine specific productivity (Qp) maintenance. Four stable clones (two from limiting dilution and two from ClonePix FL) were further evaluated. The relative mRNA expression levels of both heavy chain (HC) and light chain (LC) genes were verified at generations 0, 30–35, and 50–55 of the stability program. At generations 0 and 30–35, LC gene expression level was higher than HC gene, whereas at generation 50–55, the opposite prevailed. A high correlation was observed between Qp and HC or LC mRNA expression level for all clones at each generation analyzed along the continuous culture. The mRNA stability study was performed at steady-state culture. The LC gene displayed a higher half-life and lower decay constant than HC gene, accounting for the higher observed expression level of LC mRNA in comparison to HC mRNA. Clone R6 was highlighted due its high Qp, mRNA expression levels, and mRNA stability. Besides the benefits of applying genetic characterization for the selection of stable and high-producing clones, the present study shows for the first time the correlation between Qp and HC or LC expression levels and also mRNA stability in clones derived from human cell line Per.C6(®).