Transcriptional down-regulation of myogenin expression is associated with v-ras-induced block of differentiation in unestablished quail muscle cells

Unestablished quail myoblasts were infected with a retroviral vector encoding the oncogenic form of II-Pas in order to investigate the mechanism by which this oncoprotein interferes with terminal differentiation. Primary quail myogenic cells exhibit the simultaneous expression of the muscle regulatory genes myf-5, MyoD and myogenin in proliferative conditions. v-ras-transformed myoblasts displayed an altered growth control and lost the competence for terminal differentiation. When expression of myogenic regulatory genes was analysed, it was immediately apparent that the difference between normal and v-ras-transformed cells was limited to a severely decreased level of myogenin expression. Forced expression of exogenous myogenin in v-ras-transformed quail myoblasts led to a striking recovery of the competence for terminal differentiation. The present data show that: (i) repression of myogenin expression is linked to the differentiation defective phenotype of quail myoblasts transformed by v-ras as well as other retroviral oncogenes; (ii) correction of the differentiation-defective phenotype of v-uas-transformed myoblasts by exogenous myogenin entailed reactivation of endogenous myogenin and of the E-box-dependent transactivating function. These results strongly indicate that myogenin expression plays a central role in regulating the transition into the terminally differentiated state and that its transcriptional down-regulation represents a nodal step in v-ras-induced block of differentiation

INVESTIGACIONES EUROPEAS DE DIRECCIÓN Y ECONOMÍA DE LA EMPRESA. INFORME EDITORIAL

En este informe se revisa el proceso editorial de Investigaciones Europeas de Dirección y Economía de la Empresa durante 2009 y se avanzan algunos datos del año 2010. En 2009 se recibieron 92 manuscritos procedentes fundamentalmente de España (95,7%). Consecuentemente, el idioma más utilizado fue el español, seguido del portugués y el inglés. En este año, el tiempo medio entre recepción y publicación ha sido relativamente bajo (296 días) para lo que resulta habitual en la mayoría de publicaciones del área de economía de la empresa. La tasa de rechazo fue del 70,71%, publicándose un total de 34 artículos de investigación originales

Parathyroid hormone, calcitonin and vitamin D metabolites in beta-thalassaemia major

Serum calcium (Ca), phosphorus (P), alkaline phosphatase (Al-P), parathyroid hormone (PTH), calcitonin (CT), 25-hydroxyvitamin D3 (25OHD3), 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) levels and urinary excretion of Ca, P, hydroxyproline (OH-P) and cyclic AMP (cAMP) were determined in summer and in winter in 13 thalassaemic children (7 aged 3-5 years-group 1-; and 6 aged 10-13 years-group 2-), who had never taken vitamin D supplements or therapy, and in two groups of 14 controls of the same age. In thalassaemics of group 1 only serum Al-P levels and OH-P urinary excretion were higher than in controls (P less than 0.01). In thalassaemics of group 2 Ca (P less than 0.05), P (P less than 0.05), PTH (P less than 0.001), CT (P less than 0.001), 25OHD3 (P less than 0.05), 1,25(OH)2D3 (P less than 0.001) levels and cAMP urinary excretion (P less than 0.001) were lower, whereas Al-P (P less than 0.001) and CT (P less than 0.001) levels and urinary excretion of P (P less than 0.05) and of OH-P (P less than 0.001) were higher than in controls, both in summer and in winter. Advancing age induces in thalassaemic patients a decrease in PTH secretion and a consequent deficit in synthesis of 1,25(OH)2D3 that may explain some aspects of bone changes, which CT hypersecretion may tend to counteract

Serum GHBPs, IGFs and IGFBPs in congenital hypothyroidism during the first months of therapy

Serum GHBPs, IGFs and IGFBPs in congenital hypothyroidism during the first months of therap

Body composition after discontinuation of growth hormone (GH) in GH deficiency (GHD).

Adults with acquired GH deficiency (GHD) have been shown to have osteopenia associated with a 3-fold increase in fracture risk and exhibit increased body fat and decreased lean mass. Replacement of GH results in decreased fat mass, increased lean mass, and increased bone mineral density (BMD)