Assessment of immune function after short-term administration of recombinant human growth hormone in healthy young males

Growth hormone (GH) is a commonly used drug aimed at improving sport performance. The aim of this study is to evaluate the immunomodulatory effects of short-term administration of recombinant GH (rhGH) in healthy young males. NK cell number, activity and phenotype, T cell number, CD4(+) (Th1/Th2) cytokine production of IL2, IL4, IL6, IL10, TNF-alpha and IFN-gamma and CD4(+)/CD8(+) ratio with particular attention to the possible correlation to IGF-I production were investigated. 30 males (27 +/- A 9 years) were randomly assigned to placebo (n = 15) or drug (rhGH) 1 mg/day groups (n = 15) with daily injection for 7 days. IGF-I plasma concentration and flow cytometry data were generated at baseline and days 8, 15, 22 and 29 post injection. Data analysis used General Linear Model with repeated measures, Bonferroni correction factor and significance at p a parts per thousand currency sign 0.05. Serum IGF-I levels (ng/mL) increased significantly (p a parts per thousand currency sign 0.01) on day 8 (0.48 +/- A 0.78) after injections compared to baseline (0.31 +/- A 0.07) and days 15 (0.33 +/- A 0.06), 22 (0.29 +/- A 0.05) and 29 (0.29 +/- A 0.06). A significant time effect was noted in IL10 secretion (pg/mL) from day 15 (P = 35.14 +/- A 19.93, rhGH = 26.63 +/- A 16.39) to days 22 (P = 61.32 +/- A 20.41, rhGH = 74.99 +/- A 46.91) and 29 (P = 101.98 +/- A 67.25, rhGH = 107.74; +/- A 122.58). There was no correlation between IGF-I and NK activity, phenotype or number along with T lymphocyte number, CD4(+)/CD8(+) ratio or Th1 and Th2 cytokine production. In conclusion, cytokine secretion spectrum was not affected by short-term rhGH administration in young males

Evolutionary food web model based on body masses gives realistic networks with permanent species turnover

The networks of predator-prey interactions in ecological systems are remarkably complex, but nevertheless surprisingly stable in terms of long term persistence of the system as a whole. In order to understand the mechanism driving the complexity and stability of such food webs, we developed an eco-evolutionary model in which new species emerge as modifications of existing ones and dynamic ecological interactions determine which species are viable. The food-web structure thereby emerges from the dynamical interplay between speciation and trophic interactions. The proposed model is less abstract than earlier evolutionary food web models in the sense that all three evolving traits have a clear biological meaning, namely the average body mass of the individuals, the preferred prey body mass, and the width of their potential prey body mass spectrum. We observed networks with a wide range of sizes and structures and high similarity to natural food webs. The model networks exhibit a continuous species turnover, but massive extinction waves that affect more than $50 \%$ of the network are not observed