Browsing by Author "Garcia, K."

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    Clinical manegment of serous borderline ovarian tumors in Dr Sotero del Rio Hospital
    (2015) Puga, O.; Perez, M. V.; Garcia, K.; Saavedra, M. V.; Sáez Vásquez, Norman; Barriga, M. I.; Farías Jofré, Marcelo; Fernandez, M.; Rodriguez, T.
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    Enzymatic browning in sliced and pureed avocado: A fractal kinetic study
    (ELSEVIER SCI LTD, 2011) Quevedo, R.; Ronceros, B.; Garcia, K.; Lopez, P.; Pedreschi, F.
    Modelling of browning is essential to evaluate the effectiveness of the processes applied to obtain fresh-appearance foods and also to determine their shelf life. Computer vision and the fractal kinetic method were used to quantify browning in three avocado cultivars. Samples (avocado slices and pur e) were stored at 4 degrees C and surface images were captured in the tiff format. Browning kinetic was derived from images using the L* mean method and the fractal method. In another experiment, inhibitor kinetic was also quantified, using the polyphenol oxidase activity method (in puree samples) with 0.1%, 0.5% and 1% of sodium bisulfite. In the results for avocado slices, kinetic rate derived by the fractal kinetic method was higher than that obtained with the L* mean method, but the opposite was observed when the avocado was pulping (avocado puree). Kinetic quantified by the fractal method was similarly inhibited by bisulfite, when compared with the L* mean value or PPO activity value methods. In general, the fractal method can be used to record browning kinetic and to discriminate between avocado cultivars, initial structural state of the sample (slice or puree), or in experiments using browning inhibitors. (C) 2011 Elsevier Ltd. All rights reserved.
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    Shallow anatomy of hydrothermal systems controlled by the Liquin?e-Ofqui Fault System and the Andean Transverse Faults: Geophysical imaging of fluid pathways and practical implications for geothermal exploration
    (PERGAMON-ELSEVIER SCIENCE LTD, 2022) Perez-Estay, N.; Molina-Piernas, E.; Roquer, T.; Aravena, D.; Vargas, J. Araya; Morata, D.; Arancibia, G.; Valdenegro, P.; Garcia, K.; Elizalde, D.
    We combined geoelectric and seismic ambient noise methods to image the shallow depth (<30 m) distribution of thermal waters in two fault-controlled hydrothermal systems located in southern Chile. The bedrock depth was constrained with seismics, while hotsprings and mapped faults were imaged by low-electrical-resistivity domains (<160 omega m) defined with electrical resistivity tomographies (ERT). The distribution and shape of low-resistivitydomains suggest that thermal fluids follow complex pathways, including deep vertical conduits hosted in fractured rock and shallow horizontal bodies hosted in sediments. These results indicate that the studied hydrothermal systems are at least twice longer within the sediments than the superficial area covered by hotsprings.
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    Simvastatin interferes with cancer 'stem-cell' plasticity reducing metastasis in ovarian cancer
    (2018) Kato, S.; Liberona, M. F.; Cerda-Infante, J.; Sanchez, M.; Henriquez, J.; Bizama, C.; Bravo, M. L.; Gonzalez, P.; Gejman, R.; Branes, J.; Garcia, K.; Ibanez, C.; Owen, G. I.; Roa, J. C.; Montecinos, V.; Cuello, M. A.
    Cell plasticity of 'stem-like' cancer-initiating cells (CICs) is a hallmark of cancer, allowing metastasis and cancer progression. Here, we studied whether simvastatin, a lipophilic statin, could impair the metastatic potential of CICs in high-grade serous ovarian cancer (HGS-ovC), the most lethal among the gynecologic malignancies. qPCR, immunoblotting and immunohistochemistry were used to assess simvastatin effects on proteins involved in stemness and epithelial-mesenchymal cell plasticity (EMT). Its effects on tumor growth and metastasis were evaluated using different models (e.g., spheroid formation and migration assays, matrigel invasion assays, 3D-mesomimetic models and cancer xenografts). We explored also the clinical benefit of statins by comparing survival outcomes among statin users vs non-users. Herein, we demonstrated that simvastatin modifies the stemness and EMT marker expression patterns (both in mRNA and protein levels) and severely impairs the spheroid assembly of CICs. Consequently, CICs become less metastatic in 3D-mesomimetic models and show fewer ascites/tumor burden in HGS-ovC xenografts. The principal mechanism behind statin-mediated effects involves the inactivation of the Hippo/YAP/RhoA pathway in a mevalonate synthesis-dependent manner. From a clinical perspective, statin users seem to experience better survival and quality of life when compared with non-users. Considering the high cost and the low response rates obtained with many of the current therapies, the use of orally or intraperitoneally administered simvastatin offers a cost/effective and safe alternative to treat and potentially prevent recurrent HGS-ovCs.