Search results for "Biological Phenomena"
showing 10 items of 102 documents
MT5-MMP regulates adult neural stem cell functional quiescence through the cleavage of N-cadherin.
2014
The identification of mechanisms that maintain stem cell niche architecture and homeostasis is fundamental to our understanding of tissue renewal and repair. Cell adhesion is a well-characterized mechanism for developmental morphogenetic processes, but its contribution to the dynamic regulation of adult mammalian stem cell niches is still poorly defined. We show that N-cadherin-mediated anchorage of neural stem cells (NSCs) to ependymocytes in the adult murine subependymal zone modulates their quiescence. We further identify MT5-MMP as a membrane-type metalloproteinase responsible for the shedding of the N-cadherin ectodomain in this niche. MT5-MMP is co-expressed with N-cadherin in adult N…
Identification and relevance of the CD95-binding domain in the N-terminal region of ezrin.
2003
The CD95 (Fas/APO-1) linkage to the actin cytoskeleton through ezrin is an essential requirement for susceptibility to the CD95-mediated apoptosis in CD4+ T cells. We have previously shown that moesin was not involved in the binding to CD95. Here we further support the specificity of the ezrin/CD95 binding, showing that radixin did not bind CD95. The ezrin region specifically and directly involved in the binding to CD95 was located in the middle lobe of the ezrin FERM domain, between amino acids 149 and 168. In this region, ezrin, radixin, and moesin show 60-65% identity, as compared with the 86% identity in the whole FERM domain. Transfection of two different human cell lines with a green …
Variabilidad en la utilización de los servicios de urgencias hospitalarios del Sistema Nacional de Salud
2010
ResumenObjetivoLos objetivos de este estudio fueron estimar las tasas de frecuentación a los servicios de urgencias hospitalarios (SUH) del Sistema Nacional de Salud (SNS) por áreas de salud, el porcentaje de ingresos, las razones estandarizadas de utilización de urgencias y analizar la relación con los recursos hospitalarios.MétodosEstudio ecológico combinando información de diversas fuentes (Encuesta de Establecimientos Sanitarios con Régimen de Internado 2006 y Conjunto Mínimo de Datos Básicos 2006) para estimar la frecuentación a los SUH y el porcentaje de ingresos asociado en 164 áreas de salud de 14 comunidades autónomas (CC.AA.).ResultadosLos 35,3 millones de habitantes de las 164 ár…
Imported Stem Cells Strike against Stroke.
2015
Cells with neural stem cell (NSC)-like properties can be isolated from the cortex of adult brains following injury, but their origins and function are unclear. Now in Cell Stem Cell, Faiz et al. (2015) show that subventricular-zone-derived NSCs home to injured cortical area following stroke, where they generate reactive astrocytes.
Gatekeeper of pluripotency: A common Oct4 transcriptional network operates in mouse eggs and embryonic stem cells
2011
Abstract Background Oct4 is a key factor of an expanded transcriptional network (Oct4-TN) that governs pluripotency and self-renewal in embryonic stem cells (ESCs) and in the inner cell mass from which ESCs are derived. A pending question is whether the establishment of the Oct4-TN initiates during oogenesis or after fertilisation. To this regard, recent evidence has shown that Oct4 controls a poorly known Oct4-TN central to the acquisition of the mouse egg developmental competence. The aim of this study was to investigate the identity and extension of this maternal Oct4-TN, as much as whether its presence is circumscribed to the egg or maintained beyond fertilisation. Results By comparing …
Analysis of phosphorylation-dependent modulation of Kv1.1 potassium channels.
2003
The voltage-gated potassium channel Kv1.1 contains phosphorylation sites for protein kinase A (PKA) and protein kinase C (PKC). To study Kv1.1 protein expression and cellular distribution in regard to its level of phosphorylation, the effects of PKA and PKC activation on Kv1.1 were investigated in HEK 293 cells stably transfected with Kv1.1 (HEK 293/1). Without kinase activation, HEK 293/1 cells carry unphosphorylated Kv1.1 protein in the plasma membranes, whereas large amounts of phosphorylated and unphosphorylated Kv1.1 protein were located intracellularly. Activation of PKA resulted in phosphorylation of intracellular Kv1.1 protein, followed by a rapid translocation of Kv1.1 into the pla…
Effect of mesoglycan on macrorheologic and microrheologic parameters
1992
Abstract Whole blood filtration, mean erythrocyte aggregation, and erythrocyte membrane fluidity were examined in 10 patients with vascular atherosclerotic disease (VAD) and in 15 VAD patients with noninsulin-dependent diabetes mellitus (NIDDM) treated with mesoglycan (100 mg orally twice a day) for 30 days. The red cell membrane transverse fluidity gradient was evaluated in the VAD subjects, and the red cell membrane protein lateral mobility was measured in the VAD subjects with NIDDM. In both groups, mesoglycan treatment was responsible for an increase in erythrocyte membrane fluidity. This finding, which reflects an improvement in the dynamic properties of red cell membrane, assumes part…
Gata4 Blocks Somatic Cell Reprogramming By Directly Repressing Nanog
2012
Abstract Somatic cells can be reprogrammed to induced pluripotent stem (iPS) cells by ectopic expression of the four factors Oct4, Klf4, Sox2, and Myc. Here, we investigated the role of Gata4 in the reprogramming process and present evidence for a negative role of this family of transcription factors in the induction of pluripotency. Coexpression of Gata4 with Oct4, Klf4, and Sox2 with or without Myc in mouse embryonic fibroblasts greatly impaired reprogramming and endogenous Nanog expression. The lack of Nanog upregulation was associated with a blockade in the transition from the initiation phase of reprogramming to the full pluripotent state characteristic of iPS cells. Addition of Nanog …
Establishment of Polycomb silencing requires a transient interaction between PC and ESC
2001
Two distinct types of Polycomb complexes have been identified in flies and in vertebrates, one containing ESC and one containing PC. Using LexA fusions, we show that PC and ESC can establish silencing of a reporter gene but that each requires the presence of the other. In early embryonic extracts, we find PC transiently associated with ESC in a complex that includes EZ, PHO, PH, GAGA, and RPD3 but not PSC. In older embryos, PC is found in a complex including PH, PSC, GAGA, and RPD3, whereas ESC is in a separate complex including EZ, PHO, and RPD3.
DNA damage-induced cell death by apoptosis
2006
Following the induction of DNA damage, a prominent route of cell inactivation is apoptosis. During the last ten years, specific DNA lesions that trigger apoptosis have been identified. These include O6-methylguanine, base N-alkylations, bulky DNA adducts, DNA cross-links and DNA double-strand breaks (DSBs). Repair of these lesions are important in preventing apoptosis. An exception is O6-methylguanine-thymine lesions, which require mismatch repair for triggering apoptosis. Apoptosis induced by many chemical genotoxins is the consequence of blockage of DNA replication, which leads to collapse of replication forks and DSB formation. These DSBs are thought to be crucial downstream apoptosis-tr…