Characterization of cerebral glucose dynamics in vivo with a four-state conformational model of transport at the blood-brain barrier.

Determination of brain glucose transport kinetics in vivo at steady-state typically does not allow distinguishing apparent maximum transport rate (T(max)) from cerebral consumption rate. Using a four-state conformational model of glucose transport, we show that simultaneous dynamic measurement of brain and plasma glucose concentrations provide enough information for independent and reliable determination of the two rates. In addition, although dynamic glucose homeostasis can be described with a reversible Michaelis-Menten model, which is implicit to the large iso-inhibition constant (K(ii)) relative to physiological brain glucose content, we found that the apparent affinity constant (K(t)) was better determined with the four-state conformational model of glucose transport than with any of the other models tested. Furthermore, we confirmed the utility of the present method to determine glucose transport and consumption by analysing the modulation of both glucose transport and consumption by anaesthesia conditions that modify cerebral activity. In particular, deep thiopental anaesthesia caused a significant reduction of both T(max) and cerebral metabolic rate for glucose consumption. In conclusion, dynamic measurement of brain glucose in vivo in function of plasma glucose allows robust determination of both glucose uptake and consumption kinetics.

Metabolic alterations and increased liver mTOR expression precede the development of autoimmune disease in a murine model of lupus erythematosus

Although metabolic syndrome (MS) and systemic lupus erythematosus (SLE) are often associated, a common link has not been identified. Using the BWF1 mouse, which develops MS and SLE, we sought a molecular connection to explain the prevalence of these two diseases in the same individuals. We determined SLE- markers (plasma anti-ds-DNA antibodies, splenic regulatory T cells (Tregs) and cytokines, proteinuria and renal histology) and MS-markers (plasma glucose, non-esterified fatty acids, triglycerides, insulin and leptin, liver triglycerides, visceral adipose tissue, liver and adipose tissue expression of 86 insulin signaling-related genes) in 8-, 16-, 24-, and 36-week old BWF1 and control New-Zealand-White female mice. Up to week 16, BWF1 mice showed MS-markers (hyperleptinemia, hyperinsulinemia, fatty liver and visceral adipose tissue) that disappeared at week 36, when plasma anti-dsDNA antibodies, lupus nephritis and a pro-autoimmune cytokine profile were detected. BWF1 mice had hyperleptinemia and high splenic Tregs till week 16, thereby pointing to leptin resistance, as confirmed by the lack of increased liver P-Tyr-STAT-3. Hyperinsulinemia was associated with a down-regulation of insulin related-genes only in adipose tissue, whereas expression of liver mammalian target of rapamicyn (mTOR) was increased. Although leptin resistance presented early in BWF1 mice can slow-down the progression of autoimmunity, our results suggest that sustained insulin stimulation of organs, such as liver and probably kidneys, facilitates the over-expression and activity of mTOR and the development of SLE.

Confirmatory factor analysis of an integrated model of psycopathology assessed with MMPI-2-RF and the MCMI-III

We presented an integrated hierarchical model of psychopathology that more accurately captures empirical patterns of comorbidity between clinical syndromes and personality disorders.In order to verify the structural validity of the model proposed, this study aimed to analyze the convergence between the Restructured Clinical (RC) scales and Personality scales (PSY-5) of the MMPI-2-RF and the Clinical Syndrome and Personality Disorder scales of the MCMI-III.The MMPI-2-RF and MCMI-III were administered to a clinical sample of 377 outpatients (167 men and 210 women).The structural hypothesiswas assessed by using a Confirmatory Factor Analytic design with four common superordinate factors. An independent-cluster-basis solution was proposed based on maximum likelihood estimation and the application of several fit indices.The fit of the proposed model can be considered as good and more so if we take into account its complexity.

Nonequilibrium phase transition in a model for the propagation of innovations among economic agents

We characterize the different morphological phases that occur in a simple one-dimensional model of propagation of innovations among economic agents [X. Guardiola et al., Phys. Rev E 66, 026121 (2002)]. We show that the model can be regarded as a nonequilibrium surface growth model. This allows us to demonstrate the presence of a continuous roughening transition between a flat (system size independent fluctuations) and a rough phase (system size dependent fluctuations). Finite-size scaling studies at the transition strongly suggest that the dynamic critical transition does not belong to directed percolation and, in fact, critical exponents do not seem to fit in any of the known universality classes of nonequilibrium phase transitions. Finally, we present an explanation for the occurrence of the roughening transition and argue that avalanche driven dynamics is responsible for the novel critical behavior.

Reproducing the organic matter model of anthropogenic dark earth of Amazonia and testing the ecotoxicity of functionalized charcoal compounds

The objective of this work was to obtain organic compounds similar to the ones found in the organic matter of anthropogenic dark earth of Amazonia (ADE) using a chemical functionalization procedure on activated charcoal, as well as to determine their ecotoxicity. Based on the study of the organic matter from ADE, an organic model was proposed and an attempt to reproduce it was described. Activated charcoal was oxidized with the use of sodium hypochlorite at different concentrations. Nuclear magnetic resonance was performed to verify if the spectra of the obtained products were similar to the ones of humic acids from ADE. The similarity between spectra indicated that the obtained products were polycondensed aromatic structures with carboxyl groups: a soil amendment that can contribute to soil fertility and to its sustainable use. An ecotoxicological test with Daphnia similis was performed on the more soluble fraction (fulvic acids) of the produced soil amendment. Aryl chloride was formed during the synthesis of the organic compounds from activated charcoal functionalization and partially removed through a purification process. However, it is probable that some aryl chloride remained in the final product, since the ecotoxicological test indicated that the chemical functionalized soil amendment is moderately toxic.

Preclinical evaluation of the immunogenicity of C-type HIV-1-based DNA and NYVAC vaccines in the Balb/C mouse model.

As part of a European initiative (EuroVacc), we report the design, construction, and immunogenicity of two HIV-1 vaccine candidates based on a clade C virus strain (CN54) representing the current major epidemic in Asia and parts of Africa. Open reading frames encoding an artificial 160-kDa GagPolNef (GPN) polyprotein and the external glycoprotein gp120 were fully RNA and codon optimized. A DNA vaccine (DNA-GPN and DNA-gp120, referred to as DNA-C), and a replication-deficient vaccinia virus encoding both reading frames (NYVAC-C), were assessed regarding immunogenicity in Balb/C mice. The intramuscular administration of both plasmid DNA constructs, followed by two booster DNA immunizations, induced substantial T-cell responses against both antigens as well as Env-specific antibodies. Whereas low doses of NYVAC-C failed to induce specific CTL or antibodies, high doses generated cellular as well as humoral immune responses, but these did not reach the levels seen following DNA vaccination. The most potent immune responses were detectable using prime:boost protocols, regardless of whether DNA-C or NYVAC-C was used as the priming or boosting agent. These preclinical findings revealed the immunogenic response triggered by DNA-C and its enhancement by combining it with NYVAC-C, thus complementing the macaque preclinical and human phase I clinical studies of EuroVacc.

A multi-temporal approach to model endangered species distribution in Europe: the case of the Eurasian otter in Italy

We analysed the relationship between changes in land cover patterns and the Eurasian otter occurrence over the course of about 20 years (1985-2006) using multi-temporal Species Distribution Models (SDMs). The study area includes five river catchments covering most of the otter's Italian range. Land cover and topographic data were used as proxies of the ecological requirements of the otter within a 300-m buffer around river courses. We used species presence, pseudo-absence data, and environmental predictors to build past (1985) and current (2006) SDMs by applying an ensemble procedure through the BIOMOD modelling package. The performance of each model was evaluated by measuring the area under the curve (AUC) of the receiver-operating characteristic (ROC). Multi-temporal analyses of species distribution and land cover maps were performed by comparing the maps produced for 1985 and 2006. The ensemble procedure provided a good overall modelling accuracy, revealing that elevation and slope affected the otter's distribution in the past; in contrast, land cover predictors, such as cultivations and forests, were more important in the present period. During the transition period, 20.5% of the area became suitable, with 76% of the new otter presence data being located in these newly available areas. The multi-temporal analysis suggested that the quality of otter habitat improved in the last 20 years owing to the expansion of forests and to the reduction of cultivated fields in riparian belts. The evidence presented here stresses the great potential of riverine habitat restoration and environmental management for the future expansion of the otter in Italy

Bactericidal synergism between daptomycin and the phage lysin Cpl-1 in a mouse model of pneumococcal bacteraemia.

Combination therapy may improve the outcome of Streptococcus pneumoniae-induced bacteraemia. Here we tested the combination of two antipneumococcal agents, daptomycin and Cpl-1 (the pneumococcal Cp-1 bacteriophage lysin), in a mouse model of pneumococcal bacteraemia. Mice were challenged intraperitoneally (i.p.) with 10(6)CFU of the extremely virulent serotype 2 S. pneumoniae D39 isolate. Subtherapeutic doses of daptomycin (0.4mg/kg) and Cpl-1 (0.4mg/kg and 1mg/kg) were administrated i.p. either alone or in combination by a single bolus injection 1h after bacterial challenge. Survival rates of animals were followed over a period of 7 days. Daptomycin (0.4mg/kg) in combination with Cpl-1 (0.4mg/kg) significantly increased the percentage of surviving mice at Day 7 (80%) compared with the untreated control (0%) and daptomycin or Cpl-1 monotherapy (35% and 0%, respectively). Whilst increasing the concentration of Cpl-1 to 1.0mg/kg did not improve survival when injected alone, its combination with 0.4mg/kg daptomycin further increased the survival rate to 95%. Thus, it was found that the combination of daptomycin with Cpl-1 was synergistic and bactericidal against S. pneumoniae in a mouse model of pneumococcal bacteraemia. To our knowledge, this is the first report of synergism between daptomycin and a phage lysin demonstrated in vivo. Such a combination could represent an interesting alternative therapy for the treatment of pneumococcal bacteraemia/sepsis and possibly other severe pneumococcal infections.

Limited role of the c-Jun N-terminal kinase pathway in a neonatal rat model of cerebral hypoxia-ischemia

D-JNKI1, a cell-permeable peptide inhibitor of the c-Jun N-terminal kinase (JNK) pathway, has been shown to be a powerful neuroprotective agent after focal cerebral ischemia in adult mice and young rats. We have investigated the potential neuroprotective effect of D-JNKI1 and the involvement of the JNK pathway in a neonatal rat model of cerebral hypoxia-ischemia. Seven-day-old rats underwent a permanent ligation of the right common carotid artery followed by 2h of hypoxia (8% oxygen). Treatment with D-JNKI1 (0.3mg/kg intraperitoneally) significantly reduced early calpain activation, late caspase-3 activation and, in the thalamus, autophagosome formation, indicating an involvement of JNK in different types of cell death: necrotic, apoptotic and autophagic. However the size of the lesion was unchanged. Further analysis showed that neonatal hypoxia-ischemia induced an immediate decrease in JNK phosphorylation (reflecting mainly P-JNK1) followed by a slow progressive increase (including P-JNK3 54kDa), whereas c-jun and c-fos expression were both strongly activated immediately after hypoxia-ischemia. In conclusion, unlike in adult ischemic models, JNK is only moderately activated after severe cerebral hypoxia-ischemia in neonatal rats and the observed positive effects of D-JNKI1 are insufficient to give neuroprotection. Thus, for perinatal asphyxia, D-JNKI1 can only be considered in association with other therapies.

Respiratory failure in a mouse model of myotonic dystrophy does not correlate with the CTG repeat length.

Myotonic dystrophy (DM1) is a multisystemic disease caused by an expansion of CTG repeats in the region of DMPK, the gene encoding DM protein kinase. The severity of muscle disability in DM1 correlates with the size of CTG expansion. As respiratory failure is one of the main causes of death in DM1, we investigated the correlation between respiratory impairment and size of the (CTG)n repeat in DM1 animal models. Using pressure plethysmography the respiratory function was assessed in control and transgenic mice carrying either 600 (DM600) or >1300 CTG repeats (DMSXL). The statistical analysis of respiratory parameters revealed that both DM1 transgenic mice sub-lines show respiratory impairment compared to control mice. In addition, there is no significant difference in breathing functions between the DM600 and DMSXL mice. In conclusion, these results indicate that respiratory impairment is present in both transgenic mice sub-lines, but the severity of respiratory failure is not related to the size of the (CTG)n expansion.