Browsing by Author "Salech, Felipe"

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    Frizzled-1 receptor regulates adult hippocampal neurogenesis
    (2016) Inestrosa Cantín, Nibaldo; Mardones, Muriel D.; Andaur, Gabriela A.; Varas-Godoy, Manuel; Henriquez, Jenny F.; Salech, Felipe; Behrens, María I.; Couve, Andrés; Varela-Nallar, Lorena
    Abstract Background In the adult hippocampus new neurons are continuously generated from neural stem cells (NSCs) present at the subgranular zone of the dentate gyrus. This process is controlled by Wnt signaling, which plays a complex role in regulating multiple steps of neurogenesis including maintenance, proliferation and differentiation of progenitor cells and the development of newborn neurons. Differential effects of Wnt signaling during progression of neurogenesis could be mediated by cell-type specific expression of Wnt receptors. Here we studied the potential role of Frizzled-1 (FZD1) receptor in adult hippocampal neurogenesis. Results In the adult dentate gyrus, we determined that FZD1 is highly expressed in NSCs, neural progenitors and immature neurons. Accordingly, FZD1 is expressed in cultured adult hippocampal progenitors isolated from mouse brain. To evaluate the role of this receptor in vivo we targeted FZD1 in newborn cells using retroviral-mediated RNA interference. FZD1 knockdown resulted in a marked decrease in the differentiation of newborn cells into neurons and increased the generation of astrocytes, suggesting a regulatory role for the receptor in cell fate commitment. In addition, FZD1 knockdown induced an extended migration of adult-born neurons within the granule cell layer. However, no differences were observed in total dendritic length and dendritic arbor complexity between control and FZD1-deficient newborn neurons. Conclusions Our results show that FZD1 regulates specific stages of adult hippocampal neurogenesis, being required for neuronal differentiation and positioning of newborn neurons into the granule cell layer, but not for morphological development of adult-born granule neurons.Abstract Background In the adult hippocampus new neurons are continuously generated from neural stem cells (NSCs) present at the subgranular zone of the dentate gyrus. This process is controlled by Wnt signaling, which plays a complex role in regulating multiple steps of neurogenesis including maintenance, proliferation and differentiation of progenitor cells and the development of newborn neurons. Differential effects of Wnt signaling during progression of neurogenesis could be mediated by cell-type specific expression of Wnt receptors. Here we studied the potential role of Frizzled-1 (FZD1) receptor in adult hippocampal neurogenesis. Results In the adult dentate gyrus, we determined that FZD1 is highly expressed in NSCs, neural progenitors and immature neurons. Accordingly, FZD1 is expressed in cultured adult hippocampal progenitors isolated from mouse brain. To evaluate the role of this receptor in vivo we targeted FZD1 in newborn cells using retroviral-mediated RNA interference. FZD1 knockdown resulted in a marked decrease in the differentiation of newborn cells into neurons and increased the generation of astrocytes, suggesting a regulatory role for the receptor in cell fate commitment. In addition, FZD1 knockdown induced an extended migration of adult-born neurons within the granule cell layer. However, no differences were observed in total dendritic length and dendritic arbor complexity between control and FZD1-deficient newborn neurons. Conclusions Our results show that FZD1 regulates specific stages of adult hippocampal neurogenesis, being required for neuronal differentiation and positioning of newborn neurons into the granule cell layer, but not for morphological development of adult-born granule neurons.
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    Thalidomide for the treatment of metastatic hepatic epithelioid hemangioendothelioma: A case report with a long term follow-up
    (ELSEVIER ESPANA, 2011) Salech, Felipe; Valderrama, Sebastian; Nervi, Bruno; Carlos Rodriguez, Juan; Oksenberg, Danny; Koch, Alvaro; Smok, Gladys; Duarte, Ignacio; Maria Perez Ayuso, Rosa; Jarufe, Nicolas; Martinez, Jorge; Soza, Alejandro; Arrese, Marco; Riquelme, Arnoldo
    Hepatic epithelioid hemangioendothelioma (HEH) is an unusual, low-grade malignant vascular tumor of the liver. Here we describe a case of a 40-year-old woman who presented with abdominal pain in the upper right quadrant and giant hepatomegaly, in which imaging studies and a fine-needle liver biopsy confirmed the presence of a large EHE with an isolated lung metastasis. After balancing all possible therapeutic modalities the patient was treated conservatively with thalidomide (300 mg/day). The drug was well tolerated with minimal toxicity and the patient continues on therapy 109 months after treatment was started with no disease progression. Current therapeutic options for HEH are discussed in light of the clinical case with particular emphasis on anti-angiogenic therapies.
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    Value of adenosine deaminase (ADA) in ascitic fluid for the diagnosis of tuberculous peritonitis - A meta-analysis
    (LIPPINCOTT WILLIAMS & WILKINS, 2006) Riquelme, Arnoldo; Calvo, Mario; Salech, Felipe; Valderrama, Sebastian; Pattillo, Alejandro; Arellano, Marco; Arrese, Marco; Soza, Alejandro; Viviani, Paola; Letelier, Luz Maria
    Background and Goals: Adenosine deaminase (ADA) levels are used for diagnosing tuberculosis in several locations and although many studies have evaluated ADA levels in ascitic fluid. These studies have defined arbitrary cut-off points creating difficulties in the clinical application of the results. The goals of this study are: to determine the usefulness of ADA levels in ascitic fluid as a diagnostic test for peritoneal tuberculosis (PTB) and define the best cut-off point.