S Hsu

Publications (2)5.02 Total impact

• Article: Response of THP-1 monocytes to blue light from dental curing lights.

  J C Wataha, J B Lewis, P E Lockwood, M Noda, R L Messer, S Hsu
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  ABSTRACT: Blue light curing units (wavelengths of 400-500 nm) are a mainstay of restorative dentistry, and several high-intensity light sources have been developed to polymerize resin composites more rapidly. The biological safety of visible light has been assumed, but some reports of adverse biological effects of blue light in non-dental contexts support further evaluation of the biological safety of high-intensity blue light. The current study tested the hypothesis that blue light provokes cell stress responses resulting in the secretion of cytokines or expression of heat-shock proteins (HSP) in monocytes. Human monocytic cells were irradiated with three light sources (quartz-tungsten-halogen, plasma-arc and laser), then cellular proliferation, secretion of the inflammatory cytokine TNFalpha and induction of HSP72 were measured. Results indicated that although all three light sources significantly inhibited proliferation of monocytes, the secretion of TNFalpha was not induced following exposure to blue light and was not potentiated with administration of the activator lipopolysaccharide. Similarly, treatment with the plasma-arc light, which caused the largest temperature increase in previous studies, did not induce HSP72. The current results do not support activation of monocytes by blue light as an inflammatory risk factor in dental tissues during curing of composites. However, the results of the current study should be further verified in primary monocytes and an animal model before decisions about clinical risks are made.
  Journal of Oral Rehabilitation 03/2008; 35(2):105-10. · 1.53 Impact Factor
• Article: Blue light differentially modulates cell survival and growth.

  J C Wataha, J B Lewis, P E Lockwood, S Hsu, R L Messer, F A Rueggeberg, S Bouillaguet
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  ABSTRACT: Previous studies have reported that blue light (400-500 nm) inhibits cell mitochondrial activity. We investigated the hypothesis that cells with high energy consumption are most susceptible to blue-light-induced mitochondrial inhibition. We estimated cell energy consumption by population doubling time, and cell survival and growth by succinate dehydrogenase (SDH) activity. Six cell types were exposed to 5 or 60 J/cm(2) of blue light from quartz-tungsten-halogen (QTH), plasma-arc (PAC), or argon laser sources in monolayer culture. Post-light SDH activity correlated positively with population doubling time (R(2) = 0.91 for PAC, 0.76 for QTH, 0.68 for laser); SDH activity increased for cell types with the longest doubling times and was suppressed for cell types with shorter doubling times. Thus, light-induced exposure differentially affects SDH activity, cell survival, and growth, depending on cell energy consumption. Blue light may be useful as a therapeutic modulator of cell growth and survival.
  Journal of Dental Research 03/2004; 83(2):104-8. · 3.49 Impact Factor
• Article: Transforming growth factor beta1 dysregulation in a human oral carcinoma tumour progression model

  S. Hsu, J. L. Borke, J. B. Lewis, B. Singh, A. C. Aiken, C. T. Huynh, G. S. Schuster, G. B. Caughman, D. P. Dickinson, A. K. Smith, T. Osaki, X. F. Wang
  Cell Proliferation 01/2002; 35(3):183-192. · 2.52 Impact Factor