Oswaldo Keith Okamoto

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The identification of mesenchymal stem cell (MSC) sources that are easily obtainable is of utmost importance. Several studies have shown that MSCs could be isolated from umbilical cord (UC) units. However, the presence of MSCs in umbilical cord blood (UCB) is controversial. A possible explanation for the low efficiency of MSCs from UCB is the use of(More)
Regulation of antioxidant enzymes is critical to control the levels of reactive oxygen species in cell compartments highly susceptible to oxidative stress. In this work, we studied the regulation of a chloroplastic iron superoxide dismutase (Fe-SOD) from Lingulodinium polyedrum (formerly Gonyaulax polyedra) under different physiological conditions. A(More)
Tumorigenicity of human pluripotent stem cells is a major threat limiting their application in cell therapy protocols. It remains unclear, however, whether suppression of tumorigenic potential can be achieved without critically affecting pluripotency. A previous study has identified hyperexpressed genes in cancer stem cells, among which is E2F2, a gene(More)
Regulation and evolution of dinoflagellate luciferases are of particular interest since the enzyme is structurally unique and bioluminescence is under circadian control. In this study, three new members of the dinoflagellate luciferase gene family were identified and characterized from Pyrocystis lunula. These genes, lcfA, lcfB, and lcfC, also exhibit the(More)
We have performed cDNA microarray analyses to identify gene expression differences between highly invasive glioblastoma multiforme (GBM) and typically benign pilocytic astrocytomas (PA). Despite the significant clinical and pathological differences between the 2 tumor types, only 63 genes were found to exhibit 2-fold or greater overexpression in GBM as(More)
Aberrant expression of stem cell-related genes in tumors may confer more primitive and aggressive traits affecting clinical outcome. Here, we investigated expression and prognostic value of the neural stem cell marker CD133, as well as of the pluripotency genes LIN28 and OCT4 in 37 samples of pediatric medulloblastoma, the most common and challenging type(More)
To investigate adaptive responses to metal stress at the subcellular level, the oxidative balance in isolated chloroplasts was evaluated for the first time in the unicellular alga Gonyaulax polyedra exposed to the toxic metals Hg(2+), Cd(2+), Pb(2+), and Cu(2+). Different antioxidant responses were verified according to the metal and model of stress(More)
NaPi2b, a sodium-dependent phosphate transporter, is highly expressed in ovarian carcinomas and is recognized by the murine monoclonal antibody MX35. The antibody had shown excellent targeting to ovarian cancer in several early phase clinical trials but being murine the antibody's full therapeutic potential could not be explored. To overcome this impediment(More)
Isolation of highly tumorigenic stem-like cells from human glioblastoma specimens and cell lines has been focusing on their neural stem cells properties or capacity to efflux fluorescent dyes. Here, we report that, under standard culture conditions, human glioblastoma cells of the U87MG cell line display a predominant mesenchymal phenotype and share some of(More)
Superoxide dismutase (SOD) was studied in the agarophyte Gracilariopsis tenuifrons. Similar SOD activity (130 ± 9U mg-1) was observed in material from different regions of SouthAmerica, from different phases of the life cycle (gametophytes andtetrasporophytes), and from apical and basal sections of the thallus.In alga grown under a light-dark cycle, SOD(More)