In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.

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.\Question: Does purification of polyethylenimine polyplexes highlight the role of free polycations in gene transfer?
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.

Context: Two recent genome-wide association studies identified the liver expressed transmembrane protein adiponutrin to be associated with liver related phenotypes such as non-alcoholic fatty liver disease and liver function enzymes. These associations were not uniformly reported for various ethnicities. The aim of this study was to investigate a common non-synonymous variant within adiponutrin (rs738409, exon 3) with parameters of liver function in three independent West Eurasian study populations including a total of 4290 participants.', 'The study was performed in (1) the population based Bruneck Study (n=783), (2) the Salzburg Atherosclerosis Prevention Program in Subjects at High Individual Risk Study from Austria based on a healthy working population (n=1705), and the Utah Obesity Case-Control Study including a group of 1019 severely obese individuals (average body mass index 46.0 kg/m(2)) and 783 controls from the same geographical region of Utah. Liver enzymes measured were alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyl transferase (GGT).', 'A strong recessive association of this polymorphism was found with age and gender adjusted ALT and AST concentrations: being homozygous for the minor allele resulted in a highly significant increase of ALT concentration of 3.53 U/l (p=1.86 x 10(-9)) and of AST concentration of 2.07 U/l (p=9.58 x 10(-6)), respectively. The associations were consistently found in all three study populations.\Question: Does a common variant in the adiponutrin gene influence liver enzyme values?
The highly significant associations of this transversion polymorphism within the adiponutrin gene with increased ALT and AST concentrations support a role for adiponutrin as a susceptibility gene for hepatic dysfunction.

Context: The ratio between urinary albumin concentration (UAC) and urinary creatinine concentration (UCC) is widely used to estimate renal involvement. We examined how UAC and UCC associate with each other, with other risk factors, and with diabetic complications in a population-based sample of Type 2 diabetic patients.', 'A freshly voided morning urine specimen was provided by 1,284 consecutive, newly diagnosed diabetic patients aged 40 years or over in general practice. Albumin was measured by a polyethyleneglycol radioimmunoassay and creatinine by a modified Jaffe method.', 'In a multivariate model including UAC, UCC, age, sex, HbA1c, and urinary glucose concentration, UAC increased with both age (P=.042) and HbA1c (P=.014), while UCC decreased (P<.001 and P<.001, respectively). In two regression models, the prevalence of diabetic retinopathy (P<.001) and relatively high resting heart rate (P<.001) increased with increasing UAC but decreased with increasing UCC (P=.002 and P=.005, respectively).\Question: Is urinary creatinine concentration inversely related to glycaemic control and the presence of some diabetic complications in patients with newly diagnosed Type 2 diabetes?
The use of albumin/creatinine ratio (ACR) may introduce bias of unpredictable size and direction in comparisons of ACR with variables that are associated with UCC in their own right. In daily clinical practice, renal involvement in the individual patient can be estimated reliably with UAC or ACR measured in a freshly voided morning urine specimen, especially when considered together. However, the associations of the combined measure ACR should be interpreted with great caution in clinical and epidemiological research.