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6 results on '"Sun, Yvonne"'

2. Etanercept induces apoptosis of dermal dendritic cells in psoriatic plaques of responding patients.

Author

Malaviya, Rama, Sun, Yvonne, Tan, Jennifer K., Wang, Andrew, Magliocco, Melissa, Yao, Melissa, Krueger, James G., and Gottlieb, Alice B.

Subjects
APOPTOSIS, PSORIASIS, SKIN diseases, T cells
Abstract

Background: Etanercept is a tumor necrosis factor-α binding fusion protein that demonstrates efficacy in the treatment of psoriasis, which is accompanied by decreased plaque infiltration of T cells and myeloid dendritic cells. We hypothesized that etanercept decreases inflammatory cell infiltration by inducing apoptosis. Objective: We sought to investigate the effect of etanercept on circulating and plaque leukocyte apoptosis in psoriasis. Methods: Blood and plaque specimens were obtained from 10 patients with psoriasis treated with etanercept (25 mg subcutaneously twice weekly) for 24 weeks. Apoptosis was determined in tissue samples using immunohistochemistry and flow cytometry. Results: Etanercept selectively induced apoptosis in dermal dendritic cells in plaques of responding patients at 1 month, before most of the clinical and histologic response was achieved. No apoptosis was detected in plaque or circulating T cells or in circulating monocytes. Limitations: Addition of multiple time points earlier than 1 month would be valuable to establish the time point of maximum induction in cell apoptosis. Conclusion: Etanercept selectively induces apoptosis of pathogenic dermal dendritic cells in responding patients early in the course of treatment. [Copyright &y& Elsevier]

Published
2006
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3. Microbial Interactions with Humic Substances.

Author

Van Trump, J. Ian, Sun, Yvonne, and Coates, John D.

Abstract

The article examines the different geochemical and microbial reactivities of humic substances (HS), the role they play in a diversity of environments and their applicability to bioremediative strategies. HS are constantly encountered components in the environment and can be readily isolated from soils, waters and sediments. They are formed from the decomposition of plant, animal and microbial cells. It concludes that HS interact with microbial populations through a diversity of mechanisms.

Published
2006
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4. Branched-Chain Fatty Acids Promote Listeria monocytogenesIntracellular Infection and Virulence

Author

Sun, Yvonne and O'Riordan, Mary X. D.

Abstract

ABSTRACTAnteiso-branched-chain fatty acids (BCFA) represent the dominant group of membrane fatty acids and have been established as crucial determinants in resistance against environmental stresses in Listeria monocytogenes, a facultative intracellular pathogen. Here, we investigate the role of anteiso-BCFA in L. monocytogenesvirulence by using mutants deficient in branched-chain alpha-keto acid dehydrogenase (BKD), an enzyme complex involved in the synthesis of BCFA. In tissue culture models of infection, anteiso-BCFA contributed to intracellular growth and survival in macrophages and significantly enhanced plaque formation upon prolonged infection in L2 fibroblasts. The intracellular defects observed could be attributed partially to insufficient listeriolysin O (LLO) production, indicating a requirement for anteiso-BCFA in regulating virulence factor production. In a murine model of infection, the BKD-deficient mutant was highly attenuated, further emphasizing the importance of BKD-mediated metabolism in L. monocytogenesvirulence. This study demonstrates an underappreciated role for BCFA in bacterial pathogenesis, which may provide insight into the development and application of antimicrobial agents.

Published
2010
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5. Branched-Chain Fatty Acids Promote Listeria monocytogenes Intracellular Infection and Virulence

Author

Sun, Yvonne and O'Riordan, Mary X. D.

Abstract

Anteiso-branched-chain fatty acids (BCFA) represent the dominant group of membrane fatty acids and have been established as crucial determinants in resistance against environmental stresses in Listeria monocytogenes, a facultative intracellular pathogen. Here, we investigate the role of anteiso-BCFA in L. monocytogenes virulence by using mutants deficient in branched-chain alpha-keto acid dehydrogenase (BKD), an enzyme complex involved in the synthesis of BCFA. In tissue culture models of infection, anteiso-BCFA contributed to intracellular growth and survival in macrophages and significantly enhanced plaque formation upon prolonged infection in L2 fibroblasts. The intracellular defects observed could be attributed partially to insufficient listeriolysin O (LLO) production, indicating a requirement for anteiso-BCFA in regulating virulence factor production. In a murine model of infection, the BKD-deficient mutant was highly attenuated, further emphasizing the importance of BKD-mediated metabolism in L. monocytogenes virulence. This study demonstrates an underappreciated role for BCFA in bacterial pathogenesis, which may provide insight into the development and application of antimicrobial agents.

Published
2010

6. Why you may be more at risk for foodborne infections during the holidays.

Author

Sun, Yvonne

Abstract

The article discuses reasons for travellers for being at higher risk of becoming infected with a foodborne pathogen during Winter holidays. It is stated that Escherichia coli and Salmonella enterica are bacterial pathogens collectively responsible for more than 1.5 million episodes of foodborne illnesses per year. It is noted that susceptibility to infections in a person is determined by the state of the immune system and a competent immune defense can help in protecting from illnesses.

Published
2018

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