Thermodynamically immiscible poly(lactic acid) (PLA) and poly(ε-caprolactone) (PCL) were blended and solution-cast by adding the 3% compatibilizer (tributyl citrate, TBC) of the PCL weight. In the PLA/PCL composition range of 99/1–95/5 wt%, mechanical properties of the PLA/PCL films with TBC were always superior to those of the films without TBC. The tensile strength of 42.9 ± 3.5 MPa and the elongation at break of 10.3 ± 2.7% were observed for the 93/7 PLA/PCL films without TBC, indicating that PCL addition is effective for strength and ductility. However, the tensile strength of 54.1 ± 3.4 MPa and the elongation at break of 8.8 ± 1.8% were found for the 95/5 PLA/PCL with TBC, indicating that the effect of co-addition of PCL and TBC on mechanical properties of the films is more pronounced. No cytotoxicity was observed for the PLA/PCL films regardless of TBC addition.
Cell Proliferation ; Citric Acid ; Tensile Strength

15-deoxy-delta12,14-PGJ2(15d-PGJ2) is a natural ligand that activates the peroxisome proliferators-activated receptor (PPAR) gamma, a member of nuclear receptor family implicated in regulation of lipid metabolism and adipocyte differentiation. Recent studies have shown that 15d-PGJ2 is the potent anti-inflammatory agent functioning via PPARgamma-dependent and -independent mechanisms. Most postulated mechanisms for anti-inflammatory action of PPARgamma agonists are involved in inhibiting NF-kappaB signaling pathway. We examined the possibility that IL-6 signaling via the Jak-Stat pathway is modulated by 15d-PGJ2 in lymphocytes and also examined whether the inhibition of IL-6 signaling is dependent of PPARgamma. 15d-PGJ2 blocked IL-6 induced Stat1 and Stat3 activation in primary human lymphocytes, Jurkat cells and immortalized rheumatoid arthritis B cells. Inhibition of IL-6 signaling was induced rapidly within 15 min after treatment of 15d-PGJ2. Other PPARgamma-agonists, such as troglitazone and ciglitazone, did not inhibit IL-6 signaling, indicating that 15d-PGJ2 affect the IL-6-induced Jak-Stat signaling pathway via PPARgamma-independent mechanism. Although cycloheximide reversed 15d-PGJ2-mediated inhibition of Stat3 activation, actinomycin D had no effect on 15d-PGJ2-mediated inhibition of IL-6 signaling, indicating that inhibition of IL-6 signaling occur independent of de novo gene expression. These results show that 15d-PGJ2 specifically inhibit Jak-Stat signaling pathway in lymphocytes, and suggest that 15d-PGJ2 may regulate inflammatory reactions through the modulation of different signaling pathway other than NF-kappaB in lymphocytes.
Arthritis, Rheumatoid/metabolism/pathology ; Chromans/pharmacology ; Cycloheximide/pharmacology ; DNA-Binding Proteins/*metabolism ; Dactinomycin/pharmacology ; Gene Expression Regulation ; Humans ; Hypoglycemic Agents/pharmacology ; Interleukin-6/*pharmacology ; Jurkat Cells/metabolism/pathology ; Lymphocytes/cytology/*drug effects/*metabolism ; NF-kappa B/metabolism ; PPAR gamma/metabolism ; Phosphorylation ; Prostaglandin D2/*analogs & derivatives/pharmacology ; Protein Synthesis Inhibitors/pharmacology ; Research Support, Non-U.S. Gov't ; *Signal Transduction ; Thiazolidinediones/pharmacology ; Trans-Activators/*metabolism