Castor oil and PEG‐based shape memory polyurethane films for biomedical applications

A series of polyurethane film were prepared from poly(ethylene glycol) with different molecular weight (PEG 1500, 3000, and 8000) and castor oil by one‐shot bulk polymerization method. Hexamethylene diisocyanate and 1,4‐buthane diol were used as diisocyanate and chain extender, respectively. In order to characterize the samples, their density, swelling ratio, water contact angle, surface free energy, gel content, thermal, and viscoelastic properties were determined. The effect of the soft segment length (SSL) and hard segment content (HSC) of all polyurethane films on their shape memory behavior such as shape fixity (R_f) and shape recovery (R_r) rates were investigated by bending test. Direct contact and MTT tests were used for assessment of cell adhesion and proliferation. The relatively high R_f and R_r values were obtained for the samples programmed at high temperature difference. R_f increased with decreasing HSC. On the other hand, R_r tended to decrease with increasing SSL. After evaluating experimental data by a nonlinear equation, it was found that HSC is more effective parameter on shape memory property than SSL. The gel content, swelling ratio, and water contact angle of the samples were dependent on both SSL and HSC in their structures. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40590.     

Nutritional education for management of osteodystrophy: Impact on serum phosphorus,quality of life,and malnutrition

Introduction Osteodystrophy management includes dietary phosphorus restriction, which may limit protein intake, exacerbate malnutrition‐inflammation syndrome and mortality among hemodialysis patients. Methods A multicenter randomized controlled trial was conducted in Lebanon, to test the hypothesis that intensive nutrition education focused on phosphorus‐to‐protein balance will improve patient outcomes. Six hemodialysis units were randomly assigned to the trained hospital dietitian (THD) protocol (210 patients). Six others (184 patients) were divided equally according to the patients’ dialysis shifts and assigned to Dedicated Dietitian (DD) and Control protocols. Patients in the THD group received nutrition education from hospital dietitians who were trained by the study team on renal dietetics, but had limited time for hemodialysis patients. Patients in the DD group received individualized nutritional education on dietary phosphorus and protein management for 6 months (2‐hour/patient/month) from study renal dietitians. Patients in the control group continued receiving routine care from hospital dietitians who had limited time for these patients and were blinded to the study. Serum phosphorus (mmol/L), malnutrition‐inflammation score (MIS), health‐related quality of life (HRQOL) index and length of hospital stay (LOS) were assessed at T0 (baseline), T1 (postintervention) and T2 (post6 month follow up). Findings Only the DD protocol significantly improved serum phosphorus (T0:1.78 ± 0.5, T1:1.63 ± 0.46, T2:1.69 ± 0.53), 3 domains of the HRQOL and maintained MIS at T1, but this protective effect resolved at T2. The LOS significantly dropped for all groups. Discussion The presence of competent renal dietitians fully dedicated to hemodialysis units was superior over the other protocols in temporarily improving patient outcomes.