Browsing by Author "Sanchez, Natalia"

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    Absence of musculocutaneous nerve associated with the presence of an accessory head of the biceps brachii muscle: report of a bilateral case and its clinical implications
    (2023) Farfán Cabello, Emilio Erasmo; Araya, Felipe; Barroilhet Castillo, Manuel; Cornejo, Francisco; Gutierrez, Agustin; Vergara, Matias; Inzunza Hernández, Oscar Alejandro; Sanchez, Natalia; Tramolao Osses, Jaritza Andrea; Inostroza, Veronica
    The anatomical variants of the biceps brachii muscle (BBM) are frequent, mostly unilaterally than bilaterally, and are associated with supernumerary muscle bellies, the total absence of the muscle or one of its heads, and variations in the points of origin and insertion. In the same way, the variants of the musculocutaneous nerve (MCN) can include alterations in its course, number of branches, or anatomical relations, whereas its absence is considered an atypical variation. The aim of this work was to report the absence of musculocutaneous nerve associated with the presence of one accessory head of the biceps brachii muscle. Dissection of a female cadaver, fixed in 10% buff- ered formaldehyde, which did not present previous surgeries in the studied area was performed. Variations were noted in both upper limbs related to accessory muscle bellies and change in innervation. Anatomical relations of muscles and nerves were determined by following proximal to distal ends, relation, vascularization, and innervation pattern. The absence of MCN associated with the presence of one accessory head of the BBM were found bilaterally. These anatomical variations are atypical. Clinically, these variations can produce compressive symptoms that could generate confusing diagnostics and conduce to unnecessary procedures on the arm, inducing iatrogenic actions.
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    Depression and Antidepressants During Pregnancy: Craniofacial Defects Due to Stem/Progenitor Cell Deregulation Mediated by Serotonin
    (FRONTIERS MEDIA SA, 2021) Sanchez, Natalia; Juarez Balarezo, Jesus; Olhaberry, Marcia; González Oneto, Humberto; Muzard, Antonia; Mardonez, Maria Jesus; Franco, Pamela; Barrera, Felipe; Gaete, Marcia
    Depression is a common and debilitating mood disorder that increases in prevalence during pregnancy. Worldwide, 7 to 12% of pregnant women experience depression, in which the associated risk factors include socio-demographic, psychological, and socioecono
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    Early requirement of Hyaluronan for tail regeneration in Xenopus tadpoles
    (COMPANY OF BIOLOGISTS LTD, 2009) Contreras, Esteban G.; Gaete, Marcia; Sanchez, Natalia; Carrasco, Hector; Larrain, Juan
    Tail regeneration in Xenopus tadpoles is a favorable model system to understand the molecular and cellular basis of tissue regeneration. Although turnover of the extracellular matrix (ECM) is a key event during tissue injury and repair, no functional studies to evaluate its role in appendage regeneration have been performed. Studying the role of Hyaluronan (HA), an ECM component, is particularly attractive because it can activate intracellular signaling cascades after tissue injury. Here we studied the function of HA and components of the HA pathway in Xenopus tadpole tail regeneration. We found that transcripts for components of this pathway, including Hyaluronan synthase2 (HAS2), Hyaluronidase2 and its receptors CD44 and RHAMM, were transiently upregulated in the regenerative bud after tail amputation. Concomitantly, an increase in HA levels was observed. Functional experiments using 4-methylumbelliferone, a specific HAS inhibitor that blocked the increase in HA levels after tail amputation, and transgenesis demonstrated that the HA pathway is required during the early phases of tail regeneration. Proper levels of HA are required to sustain proliferation of mesenchymal cells in the regenerative bud. Pharmacological and genetic inhibition of GSK3 beta was sufficient to rescue proliferation and tail regeneration when HA synthesis was blocked, suggesting that GSK3 beta is downstream of the HA pathway. We have demonstrated that HA is an early component of the regenerative pathway and is required for cell proliferation during the early phases of Xenopus tail regeneration. In addition, a crosstalk between HA and GSK3 beta signaling during tail regeneration was demonstrated.
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    Expression of Transposable Elements in Neural Tissues during Xenopus Development
    (2011) Faunes, Fernando; Sanchez, Natalia; Moreno, Mauricio; Olivares, Gonzalo H.; Lee-Liu, Dasfne; Almonacid, Leonardo; Slater, Alex W.; Norambuena, Tomas; Taft, Ryan J.; Mattick, John S.; Melo, Francisco; Larrain, Juan
    Transposable elements comprise a large proportion of animal genomes. Transposons can have detrimental effects on genome stability but also offer positive roles for genome evolution and gene expression regulation. Proper balance of the positive and deleterious effects of transposons is crucial for cell homeostasis and requires a mechanism that tightly regulates their expression. Herein we describe the expression of DNA transposons of the Tc1/mariner superfamily during Xenopus development. Sense and antisense transcripts containing complete Tc1-2_Xt were detected in Xenopus embryos. Both transcripts were found in zygotic stages and were mainly localized in Spemann's organizer and neural tissues. In addition, the Tc1-like elements Eagle, Froggy, Jumpy, Maya, Xeminos and TXr were also expressed in zygotic stages but not oocytes in X. tropicalis. Interestingly, although Tc1-2_Xt transcripts were not detected in Xenopus laevis embryos, transcripts from other two Tc1-like elements (TXr and TXz) presented a similar temporal and spatial pattern during X. laevis development. Deep sequencing analysis of Xenopus tropicalis gastrulae showed that PIWI-interacting RNAs (piRNAs) are specifically derived from several Tc1-like elements. The localized expression of Tc1-like elements in neural tissues suggests that they could play a role during the development of the Xenopus nervous system.
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    Knockout or Knock-in? A Truncated D2 Receptor Protein Is Expressed in the Brain of Functional D2 Receptor Knockout Mice
    (2021) Sanchez, Natalia; Olivares-Costa, Montserrat; Gonzalez, Marcela P.; Munita, Roberto; Escobar, Angelica P.; Meza, Rodrigo; Herrera-Rojas, Mauricio; Albornoz, Jessica; Merello, Gianluca; Andres, Maria E.
    Null mice for the dopamine D2 receptor (D2R) have been instrumental in understanding the function of this protein. For our research, we obtained the functional D2R knockout mouse strain described initially in 1997. Surprisingly, our biochemical characterization showed that this mouse strain is not a true knockout. We determined by sequence analysis of the rapid 3 ' amplification of cDNA ends that functional D2R knockout mice express transcripts that lack only the eighth exon. Furthermore, immunofluorescence assays showed a D2R-like protein in the brain of functional D2R knockout mice. We verified by immunofluorescence that the recombinant truncated D2R is expressed in HEK293T cells, showing intracellular localization, colocalizing in the Golgi apparatus and the endoplasmic reticulum, but with less presence in the Golgi apparatus compared to the native D2R. As previously reported, functional D2R knockout mice are hypoactive and insensitive to the D2R agonist quinpirole. Concordantly, microdialysis studies confirmed that functional D2R knockout mice have lower extracellular dopamine levels in the striatum than the native mice. In conclusion, functional D2R knockout mice express transcripts that lead to a truncated D2R protein lacking from the sixth transmembrane domain to the C-terminus. We share these findings to avoid future confusion and the community considers this mouse strain in D2R traffic and protein-protein interaction studies.