Search results for "Acellular"
showing 10 items of 1986 documents
Allelic age of the USH2A c.2299delG mutation
2010
24 p., figuras y bibliografía
Centrins in retinal photoreceptor cells: regulators in the connecting cilium.
2008
Changes in the intracellular Ca2+ concentration regulate the visual signal transduction cascade directly or more often indirectly through Ca2+-binding proteins. Here we focus on centrins, which are members of a highly conserved subgroup of the EF-hand superfamily of Ca2+-binding proteins in photoreceptor cells of the vertebrate retina. Centrins are commonly associated with centrosome-related structures. In mammalian retinal photoreceptor cells, four centrin isoforms are expressed as prominent components in the connecting cilium linking the light-sensitive outer segment compartment with the metabolically active inner segment compartment. Our data indicate that Ca2+-activated centrin isoforms…
Membrane potential dye imaging of ventromedial hypothalamus neurons from adult mice to study glucose sensing
2013
Studies of neuronal activity are often performed using neurons from rodents less than 2 months of age due to the technical difficulties associated with increasing connective tissue and decreased neuronal viability that occur with age. Here, we describe a methodology for the dissociation of healthy hypothalamic neurons from adult-aged mice. The ability to study neurons from adult-aged mice allows the use of disease models that manifest at a later age and might be more developmentally accurate for certain studies. Fluorescence imaging of dissociated neurons can be used to study the activity of a population of neurons, as opposed to using electrophysiology to study a single neuron. This is par…
Central cholinergic functions in human amyloid precursor protein knock-in/presenilin-1 transgenic mice.
2004
Alzheimer's disease is characterized by amyloid peptide formation and deposition, neurofibrillary tangles, central cholinergic dysfunction, and dementia; however, the relationship between these parameters is not well understood. We studied the effect of amyloid peptide formation and deposition on central cholinergic function in knock-in mice carrying the human amyloid precursor protein (APP) gene with the Swedish/London double mutation (APP-SL mice) which were crossbred with transgenic mice overexpressing normal (PS1wt) or mutated (M146L; PS1mut) human presenilin-1. APP-SLxPS1mut mice had increased levels of Abeta peptides at 10 months of age and amyloid plaques at 14 months of age while AP…
GroEL and the maintenance of bacterial endosymbiosis
2004
Many eukaryotic organisms have symbiotic associations with obligate intracellular bacteria. The clonal transmission of endosymbionts between host generations should lead to the irreversible fixation of slightly deleterious mutations in their non-recombinant genome by genetic drift. However, the stability of endosymbiosis indicates that some mechanism is involved in the amelioration of the effects of these mutations. We propose that the chaperone GroEL was involved in the acquisition of an endosymbiotic lifestyle not only by means of its over-production, as proposed by Moran, but also by its adaptive evolution mediated by positive selection to improve the interaction with the unstable endosy…
Expression profiling of human fetal growth plate cartilage by EST sequencing.
2005
The differentiation of mesenchymal stem cells into hypertrophic chondrocytes is an integral and multistep process important in pattern formation, endochondral ossification, and postnatal growth of the skeleton. In recent years, novel genes involved in these processes have been identified, but still only little is known about the large-scale gene expression profile during skeletal development. We initiated an expressed sequence tag (EST) project aiming at the identification of genes and pathways involved in this complex process. Candidate genes are expected to be of value for diagnosis and treatment of monogenic and multigenic heritable disorders of the skeleton. Here, we describe the sequen…
GroEL buffers against deleterious mutations
2002
GroEL, a heat-shock protein that acts as a molecular chaperone1, is overproduced in endosymbiotic but not in free-living bacteria2,3,4, presumably to assist in the folding of conformationally damaged proteins. Here we show that the overproduction of GroEL in Escherichia coli masks the effects of harmful mutations that have accumulated during a simulated process of vertical transmission. This molecular mechanism, which may be an adaptation to the bacterium's intracellular lifestyle, is able to rescue lineages from a progressive fitness decline resulting from the fixation of deleterious mutations under strong genetic drift5,6.
Five Novel Mutations in F13B Gene Resulting in Mild FXIII Deficiency
2008
FXIII deficiency is a rare autosomal recessive disorder affecting approximately 1 out of 1–3 million inhabitants. The disease is characterized by bleeding, impaired wound repair and spontaneous abortions in females. Extracellular FXIII molecule has a tetramer structure composing of two catalytic A-subunits and two B-subunits that act as a carrier molecule. Based on genotype there are two types of FXIII deficiency: A-subunit deficiency (XIIIA) when mutations affect F13A gene and much rarely B-subunit deficiency (XIIIB) when mutations affect F13B gene. Both types result in absence of FXIII catalytical activity in plasma.
Tumor microenvironmental physiology and its implications for radiation oncology.
2004
Abstract The microenvironmental physiology of tumors is uniquely different from that of normal tissues. It is characterized, inter alia, by O 2 depletion (hypoxia, anoxia), glucose and energy deprivation, high lactate levels, and extracellular acidosis, parameters that are anisotropically distributed within the tumor mass. This hostile microenvironment is largely dictated by the abnormal tumor vasculature and heterogeneous microcirculation. Hypoxia and other hostile microenvironmental parameters are known to directly or indirectly confer resistance to irradiation leading to treatment failure. Hypoxia directly leads to a reduced "fixation" of radiation-induced DNA damage. Indirect mechanisms…
Genetic analysis of 2299delG and C759F mutations (USH2A) in patients with visual and/or auditory impairments
2004
The most common mutation in the USH2A gene (Usherin), 2299delG, causes both typical Usher (USH) syndrome type II and atypical USH syndrome, two autosomal recessive disorders, characterised by moderate to severe sensorineural hearing loss and retinitis pigmentosa (RP). Furthermore, the C759F mutation in the USH2A gene has been described in 4.5% of patients with nonsyndromic recessive RP. We have investigated the presence of the 2299delG and/or the C759F mutations in 191 unrelated Spanish patients with different syndromic and nonsyndromic retinal diseases, or with nonsyndromic hearing impairment. The 2299delG mutation was observed in patients with clinical signs of USHII or of atypical USH sy…