Publications by authors named "Kasey Chan"

The telomere length of human blastocysts exceeds that of oocytes and telomerase activity increases after zygotic activation, peaking at the blastocyst stage. Yet, it is unknown whether aneuploid human embryos at the blastocyst stage exhibit a different profile of telomere length, telomerase gene expression, and telomerase activity compared to euploid embryos. In present study, 154 cryopreserved human blastocysts, donated by consenting patients, were thawed and assayed for telomere length, telomerase gene expression, and telomerase activity using real-time PCR (qPCR) and immunofluorescence (IF) staining.

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Purpose: To investigate whether inhibition of LINE-1 affects telomere reprogramming during 2-cell embryo development.

Methods: Mouse zygotes were cultured with or without 1 µM azidothymidine (AZT) for up to 15 h (early 2-cell, G1/S) or 24 h (late 2-cell, S/G2). Gene expression and DNA copy number were determined by RT-qPCR and qPCR respectively.

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Background: Biochemical changes induced in red blood cells (RBCs) during storage may impair their function upon transfusion. Transfusion-associated stresses may further amplify storage lesion effects including increased phosphatidylserine (PS) exposure at the RBC membrane, microparticle (MP) release, and adhesion to endothelial cells (ECs). RBC stress susceptibility in vitro was investigated in relation to storage time and additive solution.

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Background: Microparticles (MPs) are small phospholipid-containing vesicles that have procoagulant properties. MPs are thought to contribute to the hemostatic potential of plasma. This study investigated the effects of whole blood (WB) hold time and leukoreduction (LR) on the MP profile and hemostatic potential of fresh-frozen plasma (FFP).

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Expression of fetal γ-globin in adulthood ameliorates symptoms of β-hemoglobinopathies by compensating for the mutant β-globin. Reactivation of the silenced γ-globin gene is therefore of substantial clinical interest. To study the regulation of γ-globin expression, we created the GG mice, which carry an intact 183-kb human β-globin locus modified to express enhanced green fluorescent protein (eGFP) from the Gγ-globin promoter.

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Microparticles (MPs) are shed from normal blood cells and may contribute to the coagulation potential of plasma. Transfusion of fresh frozen plasma (FFP) is used to correct coagulopathies and blood loss in trauma or major surgery. The role of MPs in FFP clinical efficacy is unknown.

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A greater understanding of the regulatory mechanisms that govern γ-globin expression in humans, especially the switching from γ- to β-globin, which occurs after birth, would help to identify new therapeutic targets for patients with β-hemoglobinopathy. To further elucidate the mechanisms involved in γ-globin expression, a novel fluorescent-based cellular reporter assay system was developed. Using homologous recombination, two reporter genes, DsRed and EGFP, were inserted into a 183-kb intact human β-globin locus under the control of (G)γ- or (A)γ-globin promoter and β-globin promoter, respectively.

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Background: Ultraviolet radiation (UVR) is known to induce the activation of stress-inflammation signal transduction pathways, and to induce the activity of many proteases in skin cells. It is unknown whether the activation of proteases such as furin is related to changes in the phosphorylation status of p38MAPK.

Methods: The effect of UVR on immortalized keratinocyte (HaCaT) and squamous cell carcinoma (Colo16) cells was investigated with respect to cell survival, phosphorylation of p38MAPK, and the proprotein convertase, furin.

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