SYNOPSISTo obtain poly (lactic acid) (PLA) complex fibers, spinning was performed by wet and dry methods from 5-10 g/dL chloroform solutions of poly(D-lactic acid) (PDLA) and poly( Llactic), both with a viscosity-average molecular weight of 3 X lo5. The dope was extruded from a mono-hole nozzle into coagulation baths from ethanol and chloroform for wet spinning and into a drying column kept at 60°C for dry spinning. Scanning electron microscopic observation of the as-spun fibers showed that the surface of the wet-spun fiber had large basins with diameters of 50-100 pm and many pores with diameters from sub pm to 10 pm, whereas the surface of dry-spun fiber had a microporous structure with the pore diameter of 1-3 pm. The tensile strength of the wet-spun complex fiber was very low and could not be drawn at high temperatures, in contrast to the dry-spun fiber. The tensile strength of dry-spun complex fiber increased upon hot drawing and showed the tensile strength of 94 kg/mm2 by drawing at 160°C to the draw ratio of 13. Differential scanning calorimetry revealed that the complex fibers contained both the stereocomplex crystallites ( racemic crystallites) and the crystallites of the single polymers, PDLA and PLLA, regardless of the spinning methods. The ratio of the racemic crystallites to the single-polymer crystallites increased with the draw ratio of the complex fiber.
Molecularly imprinted polymeric membranes, bearing the tetrapeptide derivative H-Asp-(OcHex)-Ile-Asp(OcHex)-Glu(OBzl)-CH2-, were prepared during the membrane preparation (casting) process in the presence of print molecule Boc-L-Trp. The molecularly imprinted membranes thus obtained showed adsorption selectivity toward a print molecule family, such as L-Trp, L-Phe, L-Ala, L-Arg, and L-Glu. The tetrapeptide derivative in the molecularly imprinted membranes preferentially recognized the L-amino acid from the D-isomer. Enantioselective permeation was attained with the present membrane, and the D-isomer was permeated in preference to the L-isomer by using the concentration difference as a driving force for membrane transport. Electrodialysis of racemic amino acid showed the possibility that permselectivity directly reflects its adsorption selectivity. It was made clear that the optical resolution was attained by the molecularly imprinted polymeric membranes.
Glucocorticoids are the primary therapy for nephrotic syndrome (NS), but have serious side effects and are ineffective in ~20–50% of patients. Thiazolidinediones have recently been suggested to be renoprotective, and to modulate podocyte glucocorticoid-mediated nuclear receptor signaling. We hypothesized that thiazolidinediones could enhance glucocorticoid efficacy in NS. We found that puromycin aminonucleoside-induced proteinuria in rats was significantly reduced by both high-dose glucocorticoids (79%) and pioglitazone (61%), but not low-dose glucocorticoids (25%). Remarkably, pioglitazone + low-dose glucocorticoids also reduced proteinuria (63%) comparably to high-dose glucocorticoids, whereas pioglitazone + high-dose glucocorticoids reduced proteinuria to almost control levels (97%). Molecular analysis revealed that both glucocorticoids and pioglitazone enhanced glomerular synaptopodin and nephrin expression, and reduced COX-2 expression, after injury. Furthermore, the glomerular phosphorylation of glucocorticoid receptor and Akt, but not PPARγ, correlated with treatment-induced reductions in proteinuria. Notably, clinical translation of these findings to a child with refractory NS by the addition of pioglitazone to the treatment correlated with marked reductions in both proteinuria (80%) and overall immunosuppression (64%). These findings together suggest that repurposing pioglitazone could potentially enhance the proteinuria-reducing effects of glucocorticoids during NS treatment.
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