Maria Pilar Fernandez

Breakthroughs spotlighting roles for extracellular nucleotides and apyrases in stress responses and growth and development.

Animal and plant cells release nucleotides into their extracellular matrix when touched, wounded, and when their plasma membranes are stretched during delivery of secretory vesicles and growth. These released nucleotides then function as signaling agents that induce rapid increases in the concentration of cytosolic calcium, nitric oxide and superoxide. These, in turn, are transduced into downstream physiological changes. These changes in plants include changes in the growth of diverse tissues, in gravitropism, and in the opening and closing of stomates. The concentration of extracellular nucleotides is controlled by various phosphatases, prominent among which are apyrases EC 3.6.1.5 (nucleoside triphosphate diphosphohydrolases, NTPDases). This review provides phylogenetic and pHMM analyses of plant apyrases as well as analysis of predicted post-translational modifications for Arabidopsis apyrases. This review also summarizes and discusses recent advances in research on the roles of apyrases and extracellular nucleotides in controlling plant growth and development. These include new findings that document how apyrases and extracellular nucleotides control auxin transport, modulate stomatal aperture, and mediate biotic and abiotic stress responses, and on how apyrase suppression leads to growth inhibition.

Analysis of unbalanced factorial designs with heteroscedastic data

The present study investigates the operating characteristics of several Box-type and Welch–James (WJ) modifications on factorial designs lacking homogeneity, normality, and orthogonality. For comparison purposes the behaviours of Proc Mixed and Proc GLM, available from the SAS program, were also examined. When the shape of the distribution was symmetric, the Box-type, WJ, and Proc Mixed approaches consistently controlled the rates of error; however, when the distribution was moderately skewed only the Box-type approach limited the number of errors to the nominal value. In distributions with extreme skewness, the procedure was predominantly conservative but showed improved rates of Type-I error control using the Box–Cox method of power transformation. The execution of Proc GLM was considerably influenced by the presence of heterogeneity and scarcely affected by the absence of normality. With regard to test sensitivity, the WJ and Proc Mixed approaches were substantially more powerful than the Box-type approach when variances and cells sizes were negatively paired. However, they were equally powerful when this relationship was positive. When the population variances were homogeneous, the differences in power slightly favoured the Proc GLM approach.

Audiovestibular manifestations in systemic vasculitis

Abstract Systemic vasculities constitute a heterogeneous group of diseases with frequent overlapping in their clinical findings and the size of the vessels involved. They may be primary or secondary to other diseases. Their common characteristic is the inflammation of blood vessels, giving rise to ischaemia. In the present article, we have reviewed the most common audiovestibular features that may be observed in patients with systemic vasculitides. Audiovestibular manifestations may be the first symptom of a systemic vasculitis. Audiological manifestations include sudden hearing loss and progressive sensorineural hearing loss. Vertigo and nystagmus are vestibular symptoms that may be observed in several systemic vasculitides. Vestibular loss in caloric test, abnormal head-shaking nystagmus, head thrust test, and positioning test (benign paroxysmal positioning vertigo) may also be found. Improvement of audiovestibular function is frequently observed in patients with giant cell arteritis following corticosteroid therapy.

Manifestaciones audiovestibulares en las vasculitis sistémicas

Systemic vasculitides constitute a heterogeneous group of diseases with frequent overlapping in their clinical findings and the size of the vessels involved. They may be primary or secondary to other diseases. Their common characteristic is the inflammation of blood vessels, giving rise to ischaemia. In the present article, we have reviewed the most common audiovestibular features that may be observed in patients with systemic vasculitides. Audiovestibular manifestations may be the first symptom of a systemic vasculitis. Audiological manifestations include sudden hearing loss and progressive sensorineural hearing loss. Vertigo and nystagmus are vestibular symptoms that may be observed in several systemic vasculitides. Vestibular loss in caloric test, abnormal head-shaking nystagmus, head thrust test and positioning test (benign paroxysmal positioning vertigo) may also be found. Improvement of audiovestibular function is frequently observed in patients with giant cell arteritis following corticosteroid therapy.

Comparison of Modern Methods for Analyzing Repeated Measures Data With Missing Values.

Missing data are a pervasive problem in many psychological applications in the real world. In this article we study the impact of dropout on the operational characteristics of several approaches that can be easily implemented with commercially available software. These approaches include the covariance pattern model based on an unstructured covariance matrix (CPM-U) and the true covariance matrix (CPM-T), multiple imputation-based generalized estimating equations (MI-GEE), and weighted generalized estimating equations (WGEE). Under the missing at random mechanism, the MI-GEE approach was always robust. The CPM-T and CPM-U methods were also able to control the error rates provided that certain minimum sample size requirements were met, whereas the WGEE was more prone to inflated error rates. In contrast, under the missing not at random mechanism, all evaluated approaches were generally invalid. Our results also indicate that the CPM methods were more powerful than the MI-GEE and WGEE methods and their superiority was often substantial. Furthermore, we note that little or no power was sacrificed by using CPM-U method in place of CPM-T, although both methods have less power in situations where some participants have incomplete data. Some aspects of the CPM-U and MI-GEE methods are illustrated using real data from 2 previously published data sets. The first data set comes from a randomized study of AIDS patients with advanced immune suppression, the second from a cohort of patients with schizotypal personality disorder enrolled in a prevention program for psychosis.

Expresión de la anexina A2 en los carcinomas epidermoides de cabeza y cuello

Objetivo La expresion de la anexina A2 (ANXA2) se ha hallado elevada en varios canceres. Sin embargo, no hay datos disponibles de la expresion de esta proteina en los carcinomas epidermoides de cabeza y cuello. El objetivo de este estudio preliminar es investigar la expresion de la ANXA2 en estos carcinomas. Material y metodo Se analizo la expresion de la ANXA2 mediante inmunohistoquimica en muestras incluidas en parafina de 9 lesiones premalignas y 21 carcinomas epidermoides de cabeza y cuello. Resultados Todas las lesiones con displasia mostraron una reduccion en la expresion de la ANXA2 respecto al tejido normal. En contraste, se aprecio expresion de la ANXA2 en todos menos uno de los tumores estudiados. La disminucion de la expresion de la ANXA2 en los carcinomas se correlaciono de forma significativa con una peor diferenciacion histologica, con tumores de mayor tamano y con metastasis ganglionares. Conclusiones Nuestros datos muestran por primera vez que la ANXA2 se expresa en los carcinomas epidermoides de cabeza y cuello e indican que su expresion se relaciona con el grado de diferenciacion de estos tumores.

Annexin A2 Expression in Head and Neck Squamous Cell Carcinoma

Objective Over-expression of annexin A2 (ANXA2) has been reported in various cancers. However, no data are available on the expression of this protein in head and neck squamous cell carcinomas (HNSCC). The objective of this preliminary study is to investigate the expression of ANXA2 in these carcinomas. Material and method ANXA2 expression was analyzed by immunohistochemistry in paraffin-embedded sections from 9 patients with premalignant lesions and 21 patients with HNSCC. Results All dysplastic tissues showed significantly reduced ANXA2 expression compared to normal tissue. In contrast, ANXA2 expression was observed in all but 1 of the tumours studied. There was a significant correlation of lower ANXA2 expression with a poorer histological differentiation, larger tumours, and nodal metastases. Conclusions Our data show for the first time that ANXA2 is expressed in head and neck squamous cell carcinomas and that its expression seems to be related with the degree of differentiation status of these tumours.

The genetic origin of mouse annexin VIII

Mouse annexin VIII cDNA was characterized by DNA sequencing of expressed sequence tag clones, molecular systematic analysis, and genetic linkage mapping to investigate its evolutionary origin. Its subfamily identity, divergence pattern, and nucleotide substitution rate were established by comparison with other annexin cDNA and deduced protein sequences. The known phylogenetic association of annexin VIII in an evolutionary clade with annexins XI, IV, V, and VIa identified these close homologs as potential progenitors or duplication products. Cladistic analysis confirmed the base position of annexin XI and its relationship to annexin IV as a direct duplication product. Although annexin VIII also derived from annexin XI, the evolutionary branching order, gene separation times, and mapping results indicated that it was probably a subsequent duplication product of annexin IV about 300 million years ago. Dates were calibrated against the assumed separation time of 75 Mya for rodents from other mammals, divergence rates were based on comparisons of all available annexin species, and relative rate tests implied individually stable gene clocks for most annexins. Linkage mapping of mouse Anx8 to the centromeric region of Chromosome (Chr) 14 placed it in a more distal homology group from previously mapped Anx7 and Anx11. Despite their synteny, the combined proximity and segregation of these three annexins diminished the likelihood that they were mutual gene duplication products.

Cambios en la vía aérea superior de pacientes con apnea obstructiva del sueño y/o roncopatía crónica en tratamiento con posicionadores mandibulares

Resumen Se han estudiado las variaciones de las vias aereas superiores (VAS) en la telerradiografia lateral de craneo en 25 adultos varones con apnea obstructiva del sueno (SAOS) y/o roncopatia cronica (RC), con Clase I dental y esqueletica, tratados con posicionadores de avance mandibular (PAM). Los resultados de nuestro trabajo muestran un claro incremento de las VAS a nivel de orofaringe en todos los casos estudiados. El estudio de los cambios en las VAS, utilizando la telerradiografia lateral de craneo, para valorar la eficacia de los PAM puede contribuir a considerar su eficacia en los casos con SAOS en los que esten indicados, aunque sera necesario contrastarlos con los resultados de la polisomnografia.

Power Differences Between the Modified Brown-Forsythe and Mixed-Model Approaches in Repeated Measures Designs

Abstract. This article compares the sensibility of the modified Brown-Forsythe (MBF) approach developed by Vallejo and Ato (2006) and a modified empirical generalized least squares (EGLS) method adjusted by the Kenward-Roger solution available in the SAS Institutes (2002) Proc Mixed program to detect the presence of an interaction effect under departures from covariance homogeneity and multivariate normality. Although none of the approaches demonstrated superior performance in all situations, our results indicate that the so-called EGLS method, based on the Akaikes Information Criterion or based on always assuming a unstructured between-subjects heterogeneous covariance pattern, was the most powerful alternative. Results also indicate that little power can be achieved with the EGLS method if the covariance matrix is specified correctly.