The impact of photodynamic therapy on the viability of Streptococcus mutans in a planktonic culture.

OBJECTIVE: This study investigated the effect of photodynamic therapy (PDT) with toluidine blue O (TBO) and a light-emitting diode (LED) on the viability of Streptococcus mutans cells in a planktonic culture. BACKGROUND DATA: Growth of Streptococcus mutans is the first step in the development of tooth decay. The use of light and dyes promotes cellular death in a noninvasive way, reducing treatment time. METHODS: The LED used in this study had output power of 116 mW, its energy was 21 J, and the fluency was 2.18 J/cm(2). Samples were prepared and divided into five groups: (1) control group (-); (2) control group (+); (3) TBO; (4) LED; and (5) LED + TBO. RESULTS: One hundred percent of the bacteria were killed following irradiation with LED and TBO. The biofilm that formed on the glass surfaces was analyzed by SEM and colony count. CONCLUSIONS: It was demonstrated that PDT was efficient at killing microorganisms and preventing the formation of biofilms.

Willingness to donate blood samples for genetic research: a survey from a community in Singapore.

Studies on the public's willingness to donate blood specimens for genetic research are few and are conducted mainly among Western countries. Little is known about the Asian community's willingness to participate in genetic research. A community-based survey was conducted on 548 adult Singaporeans to examine their willingness to donate blood samples for genetic research and its associated factors. The response rate was 70.3%. About 49.3% (95% CI, 45.1-53.5%) were willing to donate blood for genetic research. In the multivariable Cox regression analysis, willingness was significantly associated with belief in the benefits of genetic research; intention to participate in government studies; having no fear of pain, blood, injections, and needles; and non-concern about the loss of confidentiality. Reasons against donating blood were fear of pain, blood, injections, and needles (38.1%); no self-benefits (24.8%); fear of finding out about having a disease (22.3%); fear of discrimination (18.7%); and concerns about weakness (15.1%) and weight gain (9.4%). Public education programs to promote participation in genetic research should stress its benefits and address people's fears and concerns.