The Development and Application of a Quasi-dynamic Food Chain Model in Chinese Agricultural Conditions.

ABSTRACT: A quasi-dynamic food chain model (Chi-FDMT) was developed to predict the consequences of nuclear accidents on the food chain through the ingestion pathway in Chinese agricultural conditions. The Chi-FDMT structure is based on ECOSYS-87, with some revised calculation processes and the adoption of new parameters; herein, it was applied to two regions in China. The model was used to estimate the spatial and temporal patterns of crop plant activity and ingestion dose in the Chinese agricultural environment at the scale of the Fukushima nuclear disaster. A comparative study between Chi-FDMT and an equilibrium model demonstrated good agreement for depositions occurring during the growth season. The parameter sensitivity analysis of Chi-FDMT indicated that the parameters of food intake and processing factor are sensitive, and the sensitivity of the transfer factors within plant and soil-plant systems are dependent on the deposition scenario.

[Effect of monocytes activated with lipopolysaccharide on human Th17 cell differentiation].

AIM: To investigate whether monocytes activated with lipopolysaccharide(LPS) have an effect on Th17 cell differentiation in humans, CD4(+) T cell and CD14(+) monocytes activated with LPS were treated in the absence or presence of anti-CD3 mAb with various concentrations at different time points. METHODS: Purification of CD4(+) T cell and CD14(+) monocytes were performed by magnetic cell sorting and cultured together. Cultures were stimulated with LPS alone or anti-CD3 mAb alone or LPS plus anti-CD3 mAb for 3 days. In the anti-CD3 mAb stimulation cells were added different concentrations of LPS. Cells were activated under LPS/anti-CD3 costimulation for 3, 6, or 10 days. The percentage of IL-17(+) T cells and INF-γ(+) T was determined by flow cytometry. RESULTS: LPS or anti-CD3 mAb alone induced only very low levels of IL-17(+) T cells, (1.30 ± 0.19)%, (1.10 ± 0.21)%, respectively. The percentage was substantially higher in the LPS and anti-CD3 mAb costimulationa as much as(2.01 ± 0.46)%. In the presence of 0.1 µg/mL, 1 µg/mL, 10 µg/mL LPS, the proportion of Th17 reached to (1.92 ± 0.21)%, (1.30 ± 0.37)%, (1.01 ± 0.25)%. Low-concentration LPS (0.1 µg/mL) stimulation favored Th17 differentiation. The highest proportion of IL-17(+) T cells was found at day 3(2.13 ± 0.32)%, with levels declining at day 6 and day 10, while, Th1 at day 6(17.45 ± 3.04)%, declining at day 10. CONCLUSION: Low-concentration LPS stimulation plus anti-CD3 mAb in short term support optimal Th17 generation. Nevertheless, this model closely mimics the environment of rheumatoid arthritis in vivo and proposes an effective model for the generation of human Th17 cells.