Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

Context: Nonviral vectors based on polyethylenimine (PEI) usually contain an excess of PEI that is not complexed to DNA. Since unbound PEI contributes to cellular and systemic toxicity, purification of polyplexes from unbound PEI is desirable.', 'Size exclusion chromatography (SEC) was used to purify PEI polyplexes of free PEI. Transfection properties of purified polyplexes and the effect of free PEI on gene delivery were studied in vitro and in vivo after systemic application into mice.', 'SEC did not change the size and zeta-potential of polyplexes. Independent of the amount of PEI used for complex formation, purified PEI polyplexes had the same final PEI nitrogen/DNA phosphate ratio of 2.5. Notably, purified PEI polyplexes demonstrated low cellular and systemic toxicity. High transfection efficiency was achieved with purified polyplexes at high DNA concentrations (8-15 microg/ml). At low DNA concentrations (2-4 microg/ml) gene transfer with purified particles was less efficient than with polyplexes containing free PEI both in vitro and in vivo. Mechanistic studies showed that free PEI partly blocked cellular association of DNA complexes but was essential for the following intracellular gene delivery. Adding free PEI to cells treated with purified particles with a delay of up to 4 h resulted in significantly enhanced transfection efficiency compared with non-purified particles or purified particles without free PEI.
Answer: This study presents an efficient method to remove free PEI from PEI polyplexes by SEC. Our results from transfection experiments demonstrate that free PEI substantially contributes to efficient gene expression but also mediates toxic effects in a dose-dependent manner. Purified polyplexes without free PEI have to be applied at increased concentrations to achieve high transfection levels, but exhibit a greatly improved toxicity profile.
Does purification of polyethylenimine polyplexes highlight the role of free polycations in gene transfer?

Context: The orphan G protein-coupled receptor (GPR) 39 was originally identified as the receptor of obestatin. In this study, the effects and mechanisms of GPR39 on cell proliferation and differentiation were investigated in cultured porcine intramuscular preadipocytes.', 'Morphology of preadipocytes and accumulated lipid droplets within cells were identified by an inverted microscope. After transfected with constructed pCMV-GPR39 plasmid, cell proliferation was measured by using methyl thiazolyl tetrazolium method, mRNA expression of GPR39, CCAAT/enhancer binding protein-α (C/EBPα), peroxisome proliferator-activated receptor-γ (PPARγ), Caspase-9 and adipocyte determination and differentiation factor-1 (ADD1) was determined by RNA preparation and reverse transcription polymerase chain reaction, protein expression of phosphoinositide-3 kinase (PI3K), 3-phosphoinositide-dependent protein kinase 1, phosphorylated glycogen synthase kinase 3 (pGSK3), total Akt and phosphorylated Akt (pAkt) was analyzed by Western blot.', 'It found that GPR39 mRNA and protein were expressed in porcine intramuscular preadipocytes and its expression was significantly up-regulated after treatment with Zn(2+) whose function is found to be mediated by GPR39. Furthermore, over-expression of GPR39 further promoted the optical density value of cells, enhanced mRNA expression of PPARγ, C/EBPα and ADD1, and inhibited mRNA expression of Caspase-9. Protein expression of pGSK3 and pAkt was also increased by GPR39 stimulation. In addition, GPR39-induced proliferation and differentiation of porcine intramuscular preadipocytes was partially blocked by the Akt inhibitor (PDTC) and the PI3K inhibitor (LY294002).
Answer: It indicated that GPR39 was a transducer of Zn(2+), and enhanced proliferation and differentiation of porcine intramuscular preadipocytes through activation of the PI3K/Akt signaling pathway.
Does gPR39 activate proliferation and differentiation of porcine intramuscular preadipocytes through targeting the PI3K/AKT cell signaling pathway?

Context: Adolescent patients with chronic health conditions must gradually assume responsibility for their health. Self-management skills are needed for a successful transfer from adolescent to adult health care, but the development of these skills could be resource intensive. Pediatric providers are already instrumental in teaching patients about their health and may improve these skills. The aim of the study was to evaluate whether informal education of pediatric providers regarding transition improves inflammatory bowel disease (IBD) patient self-management skills.', 'Consecutive patients with IBD older than 10 years who presented to the outpatient setting were administered a survey regarding self-management behaviors in 2008 and 2011. During this time, several conferences on transition were presented to the providers.', 'In 2008, 294 patients completed the survey (82%) compared with 121 patients (89%) in 2011. The patient groups were comparable with respect to sex (boys 50% vs 42%), mean age (16.7 vs 16.2 years), and type of IBD (Crohn 68% vs 66%). The 13- to 15-year-olds reported calling in refills (11%, 8%, respectively), scheduling clinic appointment (0, 1%), preparing questions (13%, 5%), and taking the main role in talking during clinic visits (15%, 24%). The 16- to 18-year-olds reported calling in refills (13%, 27%), scheduling clinic appointments (9%, 6%), preparing questions (9%, 16%), and taking the main role in talking in clinic visits (36%, 45%). Responsibility for behaviors gradually increases with age, but did not differ significantly between 2008 and 2011.
Answer: Increasing awareness around transition readiness for pediatric providers had an insignificant effect on the self-management skills of patients with IBD. A more formal or structured approach is likely required to improve transition skills in adolescent patients.

Does provider awareness alone improve transition readiness skills in adolescent patients with inflammatory bowel disease?