No abstract

No abstract

The MTT test has been widely used as a rapid and sensitive method for screening anticancer drugs. In this paper, we used this method to assess the cytocompatibility of three materials: Kevlar 29, silicon carbide and polyvinyl chloride (PVC) in both a quantitative and a qualitative manner. The materials were prepared by cleaning in 70% ethanol, autoclaved or gammasterilized. Extracts were prepared at four time periods (1, 2, 3 and 4 weeks) and two temperatures (37°C and 80°C). The extracts were used in the MTT assay and the data were collected and analysed with ONEWAY and DUNCAN procedures using the statistical computer package SPSS x. The MTT staining procedure was also used in direct contact with the materials. The result from the MTT assay demonstrated that Kevlar, SiC and PVC extracted at 37 °C were not cytotoxic while PVC extracted at 80 °C did show some cytotoxicity, especially the material that had been gamma-sterilized. In the direct contact test the Kevlar showed no cytotoxicity. The SiC did show some localized toxicity when the material had been autoclaved, however, SiC subject to prior cleaning with ethanol showed no cytotoxicity. The PVC that had been autoclaved caused a cytotoxic response whereas the material that had been gamma-sterilized or cleaned in ethanol showed good cytocompatibility. This paper demonstrates that the MTT staining procedure is a useful technique to study the cytocompatibility of materials in both a quantitative and a qualitative manner. It is also shown that the cellular response to the materials tested is dependent on the method of preparation.

Since many fibres are very strong, they are considered to have useful potential for fibre reinforcement of orthopaedic and dental implant materials. Fibres exposed on the surface of composites may significantly influence the cellular response not only due to the chemistry but also due to the fibre size and shape. This study has concentrated on investigation of cellular responses to fibre-specific aspects of fibre-reinforced composites. Four multifilament materials with diameter less than 20 microm were used: Kevlar 29(K), silicon carbide(SiC), nylon 66(N), and polyethylene terephthalate(PET). Established cell line L929 fibroblasts were used as the cell model. Cell behaviour on the surfaces of fibres was examined using direct cell counting (after 3, 5, 8 h and 1, 2, 3 days), scanning electron microscopy (SEM) (after 2 h and 2 days), and fluorescent staining of F-actin, which was analysed by confocal laser scanning microscopy (CLSM) (after 2 h and 2 days). The results showed that fibroblasts adhered and grew very well on all fibre surfaces, although less cells were observed on PET from direct cell counting. Significant orientational behaviour of cells was found on all fibre surfaces from the SEM and CLSM analysis, independent of the bulk chemistry of the fibres.

The cell-based antioxidant activity assay as more biological relevant assay was considered to be more accurate to predict antioxidant activity in vivo than chemical activity assays. In the present study, the five main Phyllanthus emblica L. cultivars in China were subjected for cellular antioxidant activity based on HepG2 cells as well as antiproliferative activity. Total phenolics, total flavonoids and oxygen radical absorbance capacity were also measured. The results showed that Qingyougan, Binggan and Boligan (832±100, 774±52 and 704±28 μmol of quercetin equivalents/100 g) had higher cellular antioxidant activity than Tianyougan and Yougan (553±50 and 457±24 μmol of quercetin equivalents/100 g) in phosphate buffered saline wash protocol whereas, Boligan (3735±217 μmol of quercetin equivalents/100 g) had the highest cellular antioxidant activity and Tianyougan (2025±171 μmol of quercetin equivalents/100 g) had the lowest cellular antioxidant activity in no phosphate buffered saline wash protocol. The highest and lowest antiproliferative activities were observed in Binggan and Tianyougan (median effective dose: 6.95±0.11 and 14.03±0.10 mg/ml), respectively. The significant correlation was only observed between total flavonoids and cellular antioxidant activity from no phosphate buffered saline wash protocol (R2 =0.908, P<0.05), and total flavonoids and antiproliferative activity (R2 =0.887, P<0.05), suggesting the major contribution of flavonoids to the bioactivities of emblica. Overall, the data obtained revealed that different Phyllanthus emblica L. cultivars had strong cellular antioxidant and antiproliferative activities, thus should be recommended to increase consumption for health.