Purification of alpha-toxin from Clostridium perfringens type A in PEG-phosphate aqueous two-phase systems: a factorial study

BACKGROUND: Purification of a-toxin produced by Clostridium perfringens type A in aqueous two-phase systems (ATPS) was studied with a full two-level factorial design on two factors (concentrations of 8000 g mol(-1) PEG and phosphate salt at pH 8.0), to estimate the influence of these factors on the purification results. RESULTS: The partition coefficient (K), purification factor (PF) and activity yield (Y) were strongly influenced by the PEG and phosphate concentrations. Raising the levels of the two factors increased these responses. The highest purification factor (5.7) was obtained with PEG and phosphate concentrations of 17.5% and 15%, respectively. CONCLUSION: These results support the proposal that polymer excluded volume and hydrophobic interactions are the factors that drive the alpha-toxin in PEG/phosphate aqueous two-phase systems. (c) 2008 Society of Chemical Industry

Activity of the medial prefrontal cortex and amygdala underlies one-trial tolerance of rats in the elevated plus-maze

The anxiolytic effects of benzodiazepines are reduced after a single exposure of rats to elevated plus-maze test (EPM). Midazolam showed an anxioselective profile in animals submitted to one session (T1) but did not change the usual exploratory behavior of rats exposed twice (T2) to the EPM. In this study we examined further the one-trial tolerance by performing a factor analysis of the exploratory behavior of rats injected with saline before both trials as well as an immunohistochemistry study for quantification of Fos expression in encephalic structures after these sessions. Factor analysis of all behavioral categories revealed that factor I consisted of anxiety-related categories in T1 whereas these same behavioral categories loaded on factor 2 in T2. Risk assessment was also dissociated as it loaded stronger on T2 (factor 3) than on T1 (factor 4). Locomotor activity in T1 loaded on factor 5. Immunohistochemistry analyses showed that Fos expression predominated in limbic structures in T1 group. The medial prefrontal cortex and amygdala were the main areas activated in T2 group. These data suggest that anxiety and risk assessment behaviors change their valence across the EPM sessions. T2 is characterized by the emergence of a fear factor, more powerful risk assessment and medial prefrontal cortex activation. The amygdala functions as a switch between the anxiety-like patterns of T1 to the cognitive control of fear prevalent in T2. The EPM retest session is proposed as a tool for assessing the cognitive activity of rodents in the control of fear. (c) 2007 Elsevier B.V. All rights reserved.

Effects of a mixture of growth factors and proteins on the development of the osteogenic phenotype in human alveolar bone cell cultures

Strategies to promote bone repair have included exposure of cells to growth factor (GF) preparations from blood that generally include proteins as part of a complex mixture. This study aimed to evaluate the effects of such a mixture on different parameters of the development of the osteogenic phenotype in vitro. Osteoblastic cells were obtained by enzymatic digestion of human alveolar bone and cultured under standard osteogenic conditions until subconfluence. They were subcultured on Thermanox coverslips up to 14 days. Treated cultures were exposed during the first 7 days to osteogenic medium supplemented with a GFs + proteins mixture containing the major components found in platelet extracts [plate I et-derived growth factor-BB, transforming growth factor (TGF)-beta 1, TGF-beta 2, albumin, fibronectin, and thrombospondin] and to osteogenic medium alone thereafter. Control cultures were exposed only to the osteogenic medium. Treated cultures exhibited a significantly higher number of adherent cells from day 4 onward and of cycling cells at days 1 and 4, weak alkaline phosphatase (ALP) labeling, and significantly decreased levels of ALP activity and mRNA expression. At day 14, no Alizarin red-stained nodular areas were detected in cultures treated with GFs + proteins. Results were confirmed in the rat calvaria-derived osteogenic cell culture model. The addition of bone morphogenetic protein 7 or growth and differentiation factor 5 to treated cultures upregulated Runx2 and ALP mRNA expression, but surprisingly, ALP activity was not restored. These results showed that a mixture of GFs + proteins affects the development of the osteogenic phenotype both in human and rat cultures, leading to an increase in the number of cells, but expressed a less differentiated state.

Disseny d'un acoblador direccional amb metamaterials

En aquest treball es descriu el disseny d’un acoblador direccional en anell de 1.5λ, habitualment anomenat rat-race, mitjançant metamaterials. S’utilitza una línia microstrip amb gap capacitiu en sèrie i una cel·la left-handed basada en un ressonador d’anells oberts complementari (CSRR), fent així possible una reducció de la longitud de la línia de 270º en un factor 5. Gràcies a aquesta disminució de longitud, l’àrea del dispositiu és 4 vegades menor que la del rat-race convencional. La mesura mostra que el comportament és el desitjat a la freqüència d’operació.

Staff eye lens and extremity exposure in interventional cardiology: Results of the ORAMED project

Within the ORAMED project a coordinated measurement program for occupationally exposed medical staff was performed in different hospitals in Europe. The main objectives of ORAMED were to obtain a set of standardized data on doses for staff in interventional cardiology and radiology and to optimize staff protection. Doses were measured with thermoluminescent dosemeters on the ring finger and wrist of both hands, on legs and at the level of the eyes of the main operator performing interventional procedures. In this paper an overview of the doses per procedure measured during 646 interventional cardiology procedures is given for cardiac angiographies and angioplasties (CA/PTCA), radiofrequency ablations (RFA) and pacemaker and defibrillator implantations (PM/ICD). 31% of the monitored procedures were associated with no collective protective equipment, whereas 44% involved a ceiling screen and a table curtain. Although associated with the smallest air kerma - area product (KAP), PM/ICD procedures led to the highest doses. As expected, KAP and doses values exhibited a very large variability. The left side of the operator, most frequently the closest to the X-ray scattering region, was more exposed than his right side. An analysis of the effect of parameters influencing the doses, namely collective protective equipment, X-ray tube configuration and catheter access route, was performed on the doses normalized to KAP. Ceiling screen and table curtain were observed to reduce normalized doses by atmost a factor 4, much smaller than theoretical attenuation factors typical for such protections, i.e. from 10 to 100. This observation was understood as their inappropriate use by the operators and their non-optimized design. Configurations with tube above the patient led to higher normalized doses to the operator than tube below, but the effect of using a biplane X-ray suite was more complex to analyze. For CA/PTCA procedures, the upper part of the operator's body received higher normalized doses for radial than for femoral catheter access, by atmost a factor 5. This could be seen for cases with no collective protection. The eyes were observed to receive the maximum fraction of the annual dose limit almost as frequently as legs and hands, and clearly the most frequently, if the former 150 mSv and new 20 mSv recommended limits for the lens of the eye are considered, respectively.

The systemic lupus erythematosus IRF5 risk haplotype is associated with systemic sclerosis

Systemic sclerosis (SSc) is a fibrotic autoimmune disease in which the genetic component plays an important role. One of the strongest SSc association signals outside the human leukocyte antigen (HLA) region corresponds to interferon (IFN) regulatory factor 5 (IRF5), a major regulator of the type I IFN pathway. In this study we aimed to evaluate whether three different haplotypic blocks within this locus, which have been shown to alter the protein function influencing systemic lupus erythematosus (SLE) susceptibility, are involved in SSc susceptibility and clinical phenotypes. For that purpose, we genotyped one representative single-nucleotide polymorphism (SNP) of each block (rs10488631, rs2004640, and rs4728142) in a total of 3,361 SSc patients and 4,012 unaffected controls of Caucasian origin from Spain, Germany, The Netherlands, Italy and United Kingdom. A meta-analysis of the allele frequencies was performed to analyse the overall effect of these IRF5 genetic variants on SSc. Allelic combination and dependency tests were also carried out. The three SNPs showed strong associations with the global disease (rs4728142: P  = 1.34×10(-8), OR  = 1.22, CI 95%  = 1.14-1.30; rs2004640: P  = 4.60×10(-7), OR  = 0.84, CI 95%  = 0.78-0.90; rs10488631: P  = 7.53×10(-20), OR  = 1.63, CI 95%  = 1.47-1.81). However, the association of rs2004640 with SSc was not independent of rs4728142 (conditioned P  = 0.598). The haplotype containing the risk alleles (rs4728142*A-rs2004640*T-rs10488631*C: P  = 9.04×10(-22), OR  = 1.75, CI 95%  = 1.56-1.97) better explained the observed association (likelihood P-value  = 1.48×10(-4)), suggesting an additive effect of the three haplotypic blocks. No statistical significance was observed in the comparisons amongst SSc patients with and without the main clinical characteristics. Our data clearly indicate that the SLE risk haplotype also influences SSc predisposition, and that this association is not sub-phenotype-specific.

Two functional variants of IRF5 influence the development of macular edema in patients with non-anterior uveitis.

OBJECTIVE Interferon (IFN) signaling plays a crucial role in autoimmunity. Genetic variation in interferon regulatory factor 5 (IRF5), a major regulator of the type I interferon induction, has been associated with risk of developing several autoimmune diseases. In the current study we aimed to evaluate whether three sets of correlated IRF5 genetic variants, independently associated with SLE and with different functional roles, are involved in uveitis susceptibility and its clinical subphenotypes. METHODS Three IRF5 polymorphisms, rs2004640, rs2070197 and rs10954213, representative of each group, were genotyped using TaqMan® allelic discrimination assays in a total of 263 non-anterior uveitis patients and 724 healthy controls of Spanish origin. RESULTS A clear association between two of the three analyzed genetic variants, rs2004640 and rs10954213, and the absence of macular edema was observed in the case/control analysis (P FDR =5.07E-03, OR=1.48, CI 95%=1.14-1.92 and P FDR =3.37E-03, OR=1.54, CI 95%=1.19-2.01, respectively). Consistently, the subphenotype analysis accordingly with the presence/absence of this clinical condition also reached statistical significance (rs2004640: P=0.037, OR=0.69, CI 95%=0.48-0.98; rs10954213: P=0.030, OR=0.67, CI 95%=0.47-0.96), thus suggesting that both IRF5 genetic variants are specifically associated with the lack of macular edema in uveitis patients. CONCLUSION Our results clearly showed for the first time that two functional genetic variants of IRF5 may play a role in the development of macular edema in non-anterior uveitis patients. Identifying genetic markers for macular edema could lead to the possibility of developing novel treatments or preventive therapies.

Enhancement of the photoelectrochemical properties of Cl-doped ZnO nanowires by tuning their coaxial doping profile

Arrays of vertically aligned ZnO:Cl/ZnO core-shell nanowires were used to demonstrate that the control of the coaxial doping profile in homojunction nanostructures can improve their surface charge carrier transfer while conserving potentially excellent transport properties. It is experimentally shown that the presence of a ZnO shell enhances the photoelectrochemical properties of ZnO:Cl nanowires up to a factor 5. Likewise, the ZnO shell promotes the visible photoluminescence band in highly conducting ZnO:Cl nanowires. These lines of evidence are associated with the increase of the nanowires" surface depletion layer

Genome-wide association study identifies eight loci associated with blood pressure.

Elevated blood pressure is a common, heritable cause of cardiovascular disease worldwide. To date, identification of common genetic variants influencing blood pressure has proven challenging. We tested 2.5 million genotyped and imputed SNPs for association with systolic and diastolic blood pressure in 34,433 subjects of European ancestry from the Global BPgen consortium and followed up findings with direct genotyping (N ≤ 71,225 European ancestry, N ≤ 12,889 Indian Asian ancestry) and in silico comparison (CHARGE consortium, N = 29,136). We identified association between systolic or diastolic blood pressure and common variants in eight regions near the CYP17A1 (P = 7 × 10(-24)), CYP1A2 (P = 1 × 10(-23)), FGF5 (P = 1 × 10(-21)), SH2B3 (P = 3 × 10(-18)), MTHFR (P = 2 × 10(-13)), c10orf107 (P = 1 × 10(-9)), ZNF652 (P = 5 × 10(-9)) and PLCD3 (P = 1 × 10(-8)) genes. All variants associated with continuous blood pressure were associated with dichotomous hypertension. These associations between common variants and blood pressure and hypertension offer mechanistic insights into the regulation of blood pressure and may point to novel targets for interventions to prevent cardiovascular disease.

Impact of a cis-associated gene expression SNP on chromosome 20q11.22 on bipolar disorder susceptibility, hippocampal structure and cognitive performance.

BackgroundBipolar disorder is a highly heritable polygenic disorder. Recent enrichment analyses suggest that there may be true risk variants for bipolar disorder in the expression quantitative trait loci (eQTL) in the brain.AimsWe sought to assess the impact of eQTL variants on bipolar disorder risk by combining data from both bipolar disorder genome-wide association studies (GWAS) and brain eQTL.MethodTo detect single nucleotide polymorphisms (SNPs) that influence expression levels of genes associated with bipolar disorder, we jointly analysed data from a bipolar disorder GWAS (7481 cases and 9250 controls) and a genome-wide brain (cortical) eQTL (193 healthy controls) using a Bayesian statistical method, with independent follow-up replications. The identified risk SNP was then further tested for association with hippocampal volume (n = 5775) and cognitive performance (n = 342) among healthy individuals.ResultsIntegrative analysis revealed a significant association between a brain eQTL rs6088662 on chromosome 20q11.22 and bipolar disorder (log Bayes factor = 5.48; bipolar disorder P = 5.85×10(-5)). Follow-up studies across multiple independent samples confirmed the association of the risk SNP (rs6088662) with gene expression and bipolar disorder susceptibility (P = 3.54×10(-8)). Further exploratory analysis revealed that rs6088662 is also associated with hippocampal volume and cognitive performance in healthy individuals.ConclusionsOur findings suggest that 20q11.22 is likely a risk region for bipolar disorder; they also highlight the informative value of integrating functional annotation of genetic variants for gene expression in advancing our understanding of the biological basis underlying complex disorders, such as bipolar disorder.

Baremación de una escala para la orientación heurística VS algorítmica con una muestra de adultos universitarios.

El presente estudio tiene como objetivo ahondar en el conocimiento de los procesos de pensamiento de los seres humanos, concretamente en lo que se refiere a la diferenciación entre las formas de razonamiento heurístico y algorítmico. Se sigue el modelo propuesto por Groner (1991). 191 personas (licenciados y estudiantes universitarios) menores de 26 años; de ellos 103 eran mujeres y 88 hombres. Del total de la muestra, 101 personas realizaron un retest de la escala a los 60 minutos y las restantes 90 personas a los 30 días. Teniendo en cuenta el carácter exploratorio de este estudio se plantearon las siguientes hipótesis: 1. La adaptación a Lengua Española de la escala de orientación heurística de Groner, manteniendo la misma metodología, obtendrá el mismo factor bipolar obtenido en la muestra Suiza, explicando un porcentaje de varianza similar; 2. Una mejora de la metodología empleada permitirá una explicación más adecuada del constructo subyacente; 3. Existe un constructo de razonamiento general, que incorpora dos factores, uno algorítmico y otro heurístico. Escala de orientación heurística de Groner and Groner. En la primera fase (réplica al estudio suizo) se reprodujeron los análisis realizados por el grupo investigador suizo: fiabilidad de la escala, frecuencias de categorías por ítems, análisis factorial y reducción de la escala, correlaciones de las puntuaciones de la escala en las distintas versiones. Segunda fase (replanteamiento metodológico): depuración de ítems, depuración de sujetos, fiabilidad de la escala, estructuración factorial de la escala. 1. La réplica de la metodología utilizada por Groner en la construcción de la escala genera, en nuestro estudio, la reproducción de los resultados obtenidos en Suiza. 2. Esta adaptación, a la Lengua Española, no consigue apresar el factor bipolar del tipo de razonamiento humano, propuesto por Groner. 3. La versión reducida a 30 ítems, siguiendo las propuestas metodológicas de Groner y Groner, tampoco consigue apresar dicho factor. 4. La estructura factorial extraída en la primera fase de nuestra investigación responde a los dos tipos de razonamiento propuestos por Groner, pero sin producirse la dicotomización del factor. 5. La utilización de una metodología diferente mejora el modelo de Groner a nivel explicativo. 6. La versión reducida resultante del replanteamiento metodológico de la investigación, consigue apresar el constructo sugerido en la investigación Suiza. 7. El constructo de razonamiento humano resultante consta de dos factores, uno heurístico general y otro algorítmico, en vez de un único factor bipolar que los recoja. 8. Sin embargo, estos factores parecen no existir ante un análisis más estricto (de ecuaciones estructurales). Parece claro que el devenir del razonamiento humano camina por otros derroteros en las últimas décadas que lo que plantea el prometedor modelo de Groner, tanto en la literatura cognitiva como en la inteligencia artificial. Sin embargo, con las modificaciones metodológicas que planteamos nosotros, los resultados parecen esperanzadores.

Baremación de una escala para la orientación heurística VS algorítmica con una muestra de adultos no universitarios.

Este trabajo se encuadra, desde el punto de vista teórico, en el contexto de razonamiento humano, y dentro de él en el campo del llamado razonamiento heurístico, entendido como una dimensión del estilo cognitivo para la población canaria de la 'escala de razonamiento heurístico', elaborada por Groner y Groner (1991), como instrumento de medida de tal dimensión. Participaron 148 personas no universitarias, de un gran abanico de profesiones, mayores de 25 años. La primera parte del trabajo presenta una reflexión teórica en torno a la concepción del razonamiento heurístico, a fin de realizar un intento de operacionalizar tal concepto-constructo, como paso previo para su medida. En el segundo capítulo se describe un instrumento de medida surgido en 1991, elaborado por el suizo, Groner que tiene como finalidad diferenciar entre sujetos cuyo razonamiento siga una pauta de carácter heurístico frente a aquella cuya estrategia es algorítmica. Se expone cuál ha sido el desarrollo de la escala original suiza y sus características estadísticas. Los siguientes capítulos se dedican al método empleado en este estudio, para la posible estandarización de la escala en Lengua Castellana. 'Escala de razonamiento heurístico' de Groner y Groner (1991). 1. La réplica de la metodología utilizada por Groner y Groner genera en nuestro estudio la reproducción de los resultados obtenidos en Suiza. 2. Esta adaptación no logra apresar el factor bipolar del tipo de razonamiento humano propuesto por ellos (al igual que la escala original). La versión reducida de 30 ítems tampoco consigue apresar dicho factor. 3. La utilización de una metodología diferente mejora el modelo de Groner a nivel explicativo, pero mantiene las incongruencias teóricas detectadas en su metodología. 4. La estructura factorial de la primera fase de esta investigación responde a los dos tipos de razonamiento propuestos por Groner, pero sin producirse la dicotomización del factor. 5. La versión reducida resultante del replanteamiento metodológico de la investigación, consigue apresar el constructo surgido en la investigación suiza, a nivel empírico. 6. El constructo de razonamiento humano obtenido con la nueva versión de la escala consta de tres factores, uno de razonamiento heurístico general y dos algorítmicos, en vez de un único factor bipolar que los recoja. 7. El instrumento de medida propuesto en este trabajo, no permite diferenciar entre sujetos con modos de razonamiento diferenciales. No existen estilos cognitivos definidos que puedan englobarse en las definiciones propuestas de razonamiento heurístico VS algorítmico. Los datos derivados de las distintas depuraciones a que sometimos la escala parecen indicar dicha afirmación, si bien hay que hacer la salvedad de que la escala debería ser rechazada totalmente si se quiere verificar un nuevo modelo, por ejemplo el modelo de Evans (1984) o Kauswisher (1989) que contempla la interacción 'conocimiento previo x características impuestas por la tarea'.