Browsing by Author "Alvarez, Karin"

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    EGFR pathway subgroups in Chilean colorectal cancer patients, detected by mutational and expression profiles, associated to different clinicopathological features
    (2017) Alvarez, Karin; Orellana, Paulina; Villarroel, Cynthia; Contreras, Luis; Kawachi, Hiroshi; Kobayashi, Maki; Wielandt, Ana María; De la Fuente, Marjorie; Triviño, Juan Carlos; Carvallo de Saint Quentin, Pilar; Kronberg, Udo; López-Köstner, Francisco
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    Increase in decorin and biglycan in Duchenne Muscular Dystrophy: role of fibroblasts as cell source of these proteoglycans in the disease
    (2006) Fadic, Ricardo; Mezzano, Valeria; Alvarez, Karin; Cabrera, Daniel; Holmgren, Jenny; Brandan, Enrique
    Fibrosis is a common pathological feature observed in muscles of patients with. Duchenne muscular dystrophy (DMD). Biglycan and decorin are small chondroitin/dermatan sulfate proteoglycans in the muscle extracellular matrix (ECM) that belong to the family of structurally related proteoglycans called small leucine-rich repeat proteins. Decorin is considered an anti-fibrotic agent, preventing the process by blocking TGF-beta activity. There is no information about their expression in DMD patients. We found an increased amount of both proteoglycans in the ECM of skeletal muscle biopsies obtained from DMD patients. Both biglycan and decorin were augmented in the perimysium of muscle tissue, but only decorin increased in the endomysium as seen by immunohistochemical analyses. Fibroblasts were isolated from explants obtained from muscle of DMD patients and the incorporation of radioactive sulfate showed an increased synthesis of both decorin and biglycan in cultured fibroblasts compared to controls. The size of decorin and biglycan synthesized by DMD and control fibroblasts seems to be similar in size and anion charge. These findings show that decorin and biglycan are increased in DMD skeletal muscle and suggest that fibroblasts would be, at least, one source for these proteoglycans likely playing a role in the muscle response to dystrophic cell damage.
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    Lynch syndrome: selection of families by microsatellite instability and immunohistochemistry
    (SOC MEDICA SANTIAGO, 2012) Maria Wielandt, Ana; Zarate, Alejandro J.; Hurtado, Claudia; Orellana, Paulina; Alvarez, Karin; Pinto, Eliana; Contreras, Luis; Corvalan, Alejandro; Kronberg, Udo; Lopez Koestner, Francisco
    Background: Selection of patients with Lynch Syndrome (LS) for a genetic study involves the application of clinical criteria. To increase the rate of identification of mutations, the use of molecular studies as Microsatellite Instability (MSI) and Immunohistochemistry (IHC) in the tumor has been proposed. Aim: To demonstrate the usefulness of MSI and IHC in the detection of mutations in patients with LS. Material and Methods: From our Familial Colorectal Cancer Registry, families suspected of LS were selected according to Amsterdam or Bethesda clinical criteria. Screening of germline mutations of MLH1, MSH2 and MSH6 genes was performed. In addition, analysis of MS I and IHC were performed in colorectal tumors. Results: A total of 35 families were studied (19 met Amsterdam and 16 met Bethesda criteria). Twenty one families harbored a germline alteration in MLH1, MSH2 or MSH6 (18 Amsterdam and 3 Bethesda). In these families, eighteen different alterations were found, 15 of which were mutations and 3 corresponded to variants of uncertain pathogenicity. On the other hand, 80% of the tumors showed positive microsatellite instability (27 MSI-high and 1 MSI-low), and immunohistochemical testing showed that 77% of tumors had the loss of a protein. Correlation between results of tumor molecular studies and the finding of germline nucleotide change showed that IHC and MSI predicted mutations in 81 and 100% of patients, respectively. Conclusions: MSI and IHC can efficiently select patients with a high probability of carrying a mutation in DNA repair genes. (Rev Med Chile 2012; 140: 1132-1139).
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    MUSCLE MAGNETIC RESONANCE IMAGING AND HISTOPATHOLOGY IN ACTA1-RELATED CONGENITAL NEMALINE MYOPATHY
    (2014) Castiglioni, Claudia; Cassandrini, Denis; Fattori, Fabiana; Bellacchio, Emanuele; D'Amico, Adele; Alvarez, Karin; Gejman Enríquez, Roger; Diaz, Jorge; Santorelli, Filippo M.; Romero, Norma B.; Bertini, Enrico; Bevilacqua, Jorge A.