Effects of electronic cigarette liquid on monolayer and 3D tissue-engineered models of human gingival mucosa.

Background: There is limited data available on potential biological effects of E-cigarettes on human oral tissues. The aim of this study was to evaluate the effects of E-cigarette liquid on the proliferation of normal and cancerous monolayer and 3D models of human oral mucosa and oral wound healing after short-term and medium-term exposure. Methods: Normal human oral fibroblasts (NOF), immortalized OKF6-TERET-2 human oral keratinocytes, and cancerous TR146 keratinocyte monolayer cultures and 3D tissue engineered oral mucosal models were exposed to different concentrations (0.1%, 1%, 5% and 10%) of E-cigarette liquid (12 mg/ml nicotine) for 1 hour daily for three days and for 7 days. Tissue viability was monitored using the PrestoBlue assay. Wounds were also produced in the middle surface of the monolayer systems vertically using a disposable cell scraper. The alterations in the cell morphology and wound healing were visualized using light microscopy and histological examination. Results: Statistical analysis showed medium-term exposure of TR146 keratinocytes to 5% and 10% E-liquid concentrations significantly increased the viability of the cancer cells compared to the negative control. Short-term exposure of NOFs to 10% E-liquid significantly reduced the cell viability, whereas medium-term exposure to all E-liquid concentrations significantly reduced the NOF cells' viability. OKF6 cells exhibited significantly lower viability following short-term and mediumterm exposure to all E-cigarette concentrations compared to the negative control. 3D oral mucosal model containing normal oral fibroblasts and keratinocytes showed significant reduction in tissue viability after exposure to 10% E-liquid, whereas medium-term exposure resulted in significantly lower viability in 5% and 10% concentration groups compared to the negative control. There was a statistically significant difference in wound healing times of both NOF and OKF6 cells after exposure to 1%, 5% and 10% E-cigarette liquid. Conclusion: Medium-term exposure to high concentrations of the E-cigarette liquid had cytotoxic effects on normal human oral fibroblasts and OKF6 keratinocytes, but a stimulatory cumulative effect on the growth of cancerous TR146 keratinocyte cells as assessed by the PrestoBlue assay and histological evaluation of 3D oral mucosal models. In addition, E-liquid exposure prolonged the wound healing of NOF and OKF6 oral mucosa cells.

[Infections with respiratory syncytial virus in North Lebanon--prevalence during winter 2008]. / Les infections à virus respiratoire syncytial au Nord du Liban--prévalence au cours de l'hiver 2008.

Between 1 December 2007 and 31 May 2008, we analysed 120 nasopharyngeal swabs for the presence respiratory syncytial virus (RSV) infection in 120 children aged 15 days to 6 years, hospitalized in 2 hospitals in North Lebanon. Of the 120 samples, 32 were positive (26.7%) for RSV. There was a peak in January which progressively disappeared from February to May. Being positive for RSV was significantly associated with the presence of rhinorrhoea and dyspnoea as clinical symptoms and the absence of pneumonia signs on chest X-ray and the diagnosis of bronchitises or bronchiolitis. Testing for RSV is important in cases of respiratory infections in children as it may limit unnecessary prescription of antibiotics.

[Infections with respiratory syncytial virus in North Lebanon-prevalence during winter 2008]

Between 1 December 2007 and 31 May 2008, we analysed 120 nasopharyngeal swabs for the presence respiratory syncytial virus [RSV] infection in 120 children aged 15 days to 6 years, hospitalized in 2 hospitals in North Lebanon. Of the 120 samples, 32 were positive [26.7%] for RSV. There was a peak in January which progressively disappeared from February to May. Being positive for RSV was significantly associated with the presence of rhinorrhoea and dyspnoea as clinical symptoms and the absence of pneumonia signs on chest X-ray and the diagnosis of bronchitises or bronchiolitis. Testing for RSV is important in cases of respiratory infections in children as it may limit unnecessary prescription of antibiotics