69 research outputs found

    THE USE OF SEXUALLY PROPAGATED SCLERACTINIAN CORALS FOR REEF RESTORATION

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    Ph.DDOCTOR OF PHILOSOPH

    25-Hydroxyvitamin D-3 induces osteogenic differentiation of human mesenchymal stem cells

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    25-Hydroxyvitamin D-3 [25(OH)D-3] has recently been found to be an active hormone. Its biological actions are demonstrated in various cell types. 25(OH)D-3 deficiency results in failure in bone formation and skeletal deformation. Here, we investigated the effect of 25(OH)D-3 on osteogenic differentiation of human mesenchymal stem cells (hMSCs). We also studied the effect of 1 alpha, 25-dihydroxyvitamin D-3[1 alpha,25-(OH)(2)D-3], a metabolite of 25(OH)D-3. One of the vitamin D responsive genes, 25(OH)D-3-24-hydroxylase (cytochrome P450 family 24 subfamily A member 1) mRNA expression is up-regulated by 25(OH)D-3 at 250-500 nM and by 1 alpha, 25-(OH)(2)D-3 at 1-10 nM. 25(OH)D-3 and 1 alpha, 25-(OH)(2)D-3 at a time-dependent manner alter cell morphology towards osteoblast-associated characteristics. The osteogenic markers, alkaline phosphatase, secreted phosphoprotein 1 (osteopontin), and bone gamma-carboxyglutamate protein (osteocalcin) are increased by 25(OH)D-3 and 1 alpha,25-(OH)(2)D-3 in a dose-dependent manner. Finally, mineralisation is significantly increased by 25(OH)D-3 but not by 1 alpha, 25-(OH)(2)D-3. Moreover, we found that hMSCs express very low level of 25(OH)D-3-1 alpha-hydroxylase (cytochrome P450 family 27 subfamily B member 1), and there is no detectable 1 alpha, 25-(OH)(2)D-3 product. Taken together, our findings provide evidence that 25(OH)D-3 at 250-500 nM can induce osteogenic differentiation and that 25(OH)D-3 has great potential for cell-based bone tissue engineering.Peer reviewe

    Graft-vs-tumor effect in patients with advanced nasopharyngeal cancer treated with nonmyeloablative allogeneic PBSC transplantation

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    While nonmyeloablative peripheral blood stem cell transplantation (NST) has shown efficacy against several solid tumors, it is untested in nasopharyngeal cancer (NPC). In a phase II clinical trial, 21 patients with pretreated metastatic NPC underwent NST with sibling PBSC allografts, using CY conditioning, thymic irradiation and in vivo T-cell depletion with thymoglobulin. Stable lymphohematopoietic chimerism was achieved in most patients and prophylactic CYA was tapered at a median of day +30. Seven patients (33%) showed partial response and three (14%) achieved stable disease. Four patients were alive at 2 years and three showed prolonged disease control of 344, 525 and 550 days. With a median follow-up of 209 (4–1147) days, the median PFS was 100 days (95% confidence interval (CI), 66–128 days), and median OS was 209 days (95% CI, 128–236 days). Patients with chronic GVHD had better survival—median OS 426 days (95% CI, 194–NE days) vs 143 days (95% CI, 114–226 days) (P=0.010). Thus, NST may induce meaningful clinical responses in patients with advanced NPC

    Collegiate Commentary

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    University of Edinburg Teaching Matters Newslette

    Educational Technology Tools to Support Online Teaching

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    Teaching ConnectionsSingapor

    Osteoinductive effects of 1α, 25 Dihydroxyvitamin D3 on human mesenchymal stem cells.

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    Bone healing poses a challenge for clinicians due to the bone’s poor regenerative property. While autologous bone grafting remains the most common solution for bone defects, it causes various proven side effects. Recent developments seem to suggest that cell-based bone tissue engineering (BTE) involving human mesenchymal stem cells (hMSCs) is a more viable solution. This project aims to characterize the proliferative and osteoinductive effects of 1,25-(OH)2-D3 on hMSCs, by subjecting the cells to various concentrations of 1,25-(OH)2-D3 in vitro. Our results highlighted the dose-dependent growth inhibitory effects on hMSCs after 1,25-(OH)2-D3 administration. In addition, we have shown that supra-physiological concentrations (1 nM and 10 nM) of 1,25-(OH)2-D3 up-regulated various osteogenic markers including alkaline phosphatase (ALP) activity, extracellular mineralization, osteocalcin secretion, mRNA expression of osteocalcin and osteopontin , and also promoted early onset of hMSC morphological changes. Conversely, physiological concentrations (0.05 nM and 0.1 nM) of 1,25-(OH)2-D3 produced limited osteoinductive effects in vitro. As a practical application, 1,25-(OH)2-D3 was encapsulated in a nanoparticle, PEGylated polyaspartic acid with L-phenylalanine side chains (PAph-5), as a vehicle for in vitro delivery to hMSCs. This project has underlined the clinical implications of 1,25-(OH)2-D3 and demonstrated its potential application to BTE with the aid of nanotechnology. *I will like to express my gratitude to Institute of Bioengineering and Nanotechnology (IBN), IBN Youth Research Program, Biomedical Research Council and A*STAR, for their support that made this work possible.Bachelor of Science in Biological Science

    High Impact Practices in Internships

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    CDTL Teaching Connection

    3 Reasons Why Educators Should Partner Students in Teaching and Learning

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    CDTL Teaching ConnectionsSingapor

    From Specialist to Teacher-Scholar: The Influence of SoTL on the Journey of an Early Career Academic

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    Asian Journal of the Scholarship of Teaching and Learning12188-95Singapor

    Lessons learnt from our interdisciplinary team-teaching experience

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    CDTL Teaching Connection
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