86,546 research outputs found
FGF and EGF differently affect differentiation of murine retinal stem cells in vitro
No full textPurpose: The developmental processes that mediate differentiation from retinal stem cells (RSC) to different retinal neuronal types remain unclear. During retinal development, progenitor cells modify expression of growth factor (GF) receptors and their differentiation potentials. Similarly, RSC in culture may exhibit alternative molecular characteristics in response to different GF stimuli.Methods: RSC were purified from the adult ciliary margin and exposed to fibroblast growth factor (FGF), epidermal growth factor (EGF), or FGF+EGF. Proliferation was analyzed by bromodeoxyuridine (BrdU) labeling. Differentiation was evaluated by immunofluorescence with antibodies recognizing specific markers of different retinal cell types.Results: In the absence of GF stimuli, RSC in culture expressed FGFR1, similar to early progenitors in vivo. Treatment with GFs up-regulated the expression of both fibroblast growth factor receptor 1 (FGFR1) and epidermal growth factor receptor (EGFR). Exposure to either FGF, EGF, or FGF+EGF strongly affected retinal stem cell-renewal and differentiation. Specifically, expression of progenitor/stem cell markers and stem cell-renewal was higher in the presence of FGF than in that of EGF. FGF favored differentiation of RSC into photoreceptor-like cells. Finally, we showed that the treatment of the primary culture with FGF+EGF imprinted the cells and limited plasticity in subsequent differentiation.Conclusions: We provide evidence that conditions of the primary culture have a strong influence on cell-renewal and differentiation potentials of RSC
The mouse model for ocular albinisin type 1 (OA1) as a tool to study Oa1 function in RPE development
No full textPurpose: Ocular Albinism type 1 (OA1) is an X-linked form of albinism isolated to the eye. The disease causes a severe visual handicap in affected males, manifesting foveal hypoplasia, horizontal and rotatory nystagmus, strabismus, photophobia and lack of stereoscopic vision. Histological analysis of patient melanocytes from the RPE and the skin reveals giant melanosomes (macromelanosomes). Mutations causing this disease were identified in OA1 gene. OA1 is specifically expressed in the retinal pigment epithelium (RPE) and in skin melanocytes . The protein is localized on the melanosomal membrane and displays characteristics typical of the seven transmembrane G protein coupled receptors. In order to understand the biological function of OA1, we generated a mouse model for the disease.
Methods: To generate Oa1 null mice, we deleted the first exon of Oa1 by homologous recombination in ES cells. Histological studies were performed on RPE of wild-type and mutant mice. Interactions of Oa1 with other melanosomal proteins was investigated by mating Oa1 null mice with p and c mice. Ultrastructural and biochemical analyses were conducted in double mutant mice.
Results: Histological analysis of the eyes in Oa1 mutants showed that the RPE was more lightly pigmented. Abnormally large melanosomes (macromelanosomes) could be identified by electron microscopy within the RPE. Interestingly, macromelanosomes could be seen just after birth in mutant mice. Oa1 knock-out mice display a misrouting of the optic fibers as in OA1 patients. A significant decrease of ipsilateral optic fibers could be measured in Oa1 knock-out mice as found in other albino mice. To investigate the function of Oa1 on the melanosomal membrane and its interaction with other genes causing different forms of albinism, we mated Oa1 null mice with p and c mice. Ultrastructural and biochemical analyses were performed in double mutant mice, finding a correlation of the macromelanosomal phenotype and level of pigmentation. We have also studied genes regulating Oa1 expression during development (e.i. Mitf) and we have started experiments aimed to the identification of genes downstream to it.
Conclusion: We developed a mouse model for OA1. Our data demonstrate that the Oa1 knock-out mouse is indeed a good model for the study of OA1 pathology. Furthermore the mouse model will be valuable for the identification of factors mediating RPE influence on retinal development
"Completamento del sistema automatico per la preparazione dei vetrini di base"
No full textAcquisizione di medie e grandi attrezzature scientifiche, dal titolo "Completamento del sistema automatico per la preparazione dei vetrini di base, nel corso della ricerca "Caratteristiche morfologiche, Istochimiche ed immunochimiche dei vasi, dei nervi e deimuscoli implicati nelle malformazioni cranio-facciali,su frammenti di tessutoprelevati durante gli interventichirurgici in camerca operatoria".
Progetto C26G065NA
Vasoactive intestinal peptide increases hepatic transduction and reduces innate immune response following administration of helper-dependent Ad.
No full textMicrophthalmia transcription factor controls expression of the Ocular albinism type 1 gene.
No full textsubmitte
The microphthalmia transcription factor (Mitf) controls expression of the ocular albinism type 1 gene: link between melanin synthesis and melanosome biogenesis.
No full textMelanogenesis is the process that regulates skin and eye pigmentation. Albinism, a genetic disease causing pigmentation defects and visual disorders, is caused by mutations in genes controlling either melanin synthesis or melanosome biogenesis. Here we show that a common transcriptional control regulates both of these processes. We performed an analysis of the regulatory region of Oa1, the murine homolog of the gene that is mutated in the X-linked form of ocular albinism, as Oa1's function affects melanosome biogenesis. We demonstrated that Oa1 is a target of Mitf and that this regulatory mechanism is conserved in the human gene. Tissue-specific control of Oa1 transcription lies within a region of 617 bp that contains the E-box bound by Mitf. Finally, we took advantage of a virus-based system to assess tissue specificity in vivo. To this end, a small fragment of the Oa1 promoter was cloned in front of a reporter gene in an adeno-associated virus. After we injected this virus into the subretinal space, we observed reporter gene expression specifically in the retinal pigment epithelium, confirming the cell-specific expression of the Oa1 promoter in the eye. The results obtained with this viral system are a preamble to the development of new gene delivery approaches for the treatment of retinal pigment epithelium defects
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
[Newspaper Clipping: Author Claims Evidence of Second JFK Assassin #1]
No full textNewspaper article titled "Author Claims Evidence of Second JFK Assassin." The article states that author Richard J. Whalen concluded "that there is circumstantial evidence to support the theory of a second assassin in the shooting of President John F. Kennedy.
Also By The Same Author: AKTiveAuthor, a Citation Graph Approach to Name Disambiguation
No full textThe desire for definitive data and the semantic web drive for inference over heterogeneous data sources requires co-reference resolution to be performed on those data. In particular, name disambiguation is required to allow accurate publication lists, citation counts and impact measures to be determined. This paper describes a graph-based approach to author disambiguation on large-scale citation networks. Using self-citation, co-authorship and document source analyses, AKTiveAuthor clusters papers, achieving precision of 0.997 and recall of 0.818 over a test group of eight surname clusters
John F. Kennedy telegram to Roosevelt
No full textJersey Homesteads (later the Borough of Roosevelt) was established in the 1930s as an agro-industrial cooperative community. It was established specifically for urban Jewish garment workers, many of whom had emigrated from Europe. President John F. Kennedy sent a telegram to the citizens of Roosevelt, New Jersey, apologizing for not being able to attend the memorial dedication in honor of former President Franklin Delano Roosevelt. (Jersey Homesteads became Roosevelt in 1945 in honor of the president.) President Kennedy expressed his gratitude to the people of Roosevelt for constructing the memorial, and commented that it will serve as a constant reminder of Roosevelt's good works
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