TASK DEFINITION: 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.
PROBLEM: Context: P53 is a key protein which controls cell cycle arrest and apoptosis in response to DNA damage. Auto-antibodies against p53 have been detected in some cancer patients and also in patients with autoimmune diseases. In these patients, the main cause of anti-p53 antibody occurrence was considered to be increased intracellular p53 protein in cancer cells and autoreactive lymphocytes, respectively. Intracellular p53 also increases with cardiomyocyte apoptosis during heart failure and autoreactive lymphocytes play a role in the course of idiopathic dilated cardiomyopathy (IDC) and ischemic cardiomyopathy (ICM). Based on these observations, we hypothesized that anti-p53 antibody response may also occur in patients with heart failure due to ICM and IDC.', 'The aim of this study was to evaluate anti-p53 antibodies in the serum of patients with heart failure due to IDC and ICM.', '70 eligible patients with heart failure and severe left ventricular systolic dysfunction (mean fractional shortening 12.03 +/- 3.93%) were included in the study. The aetiology of heart failure was IDC in 26 patients and ICM in 44 patients, according to the angiographic and echocardiographic findings.', 'Anti-p53 antibodies were not detected in any of the patients.\Question: Do serum anti-p53 antibodies occur in patients with heart failure due to idiopathic dilated and ischemic cardiomyopathies?

SOLUTION: Anti-p53 antibodies do not occur in patients with heart failure due to IDC and ICM, possible explanations are discussed in the text.

PROBLEM: 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?

SOLUTION: 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.

PROBLEM: Context: Self-reported health-related quality of life (HRQL) and changes in HRQL have been shown to predict mortality and/or adverse events in patients with coronary artery disease. MacNew Heart Disease HRQL questionnaire scores were examined as predictors of 4-year all-cause mortality.', 'Following referral for angioplasty in 385 patients with coronary artery disease, data were analyzed for differences in all-cause mortality by MacNew Global and subscale baseline and 1- and 3-month change scores (deteriorated ≥0.50; unchanged (-0.49 to +0.49); and improved ≥0.50 points).', 'Mean baseline, 1-month, and 3-month MacNew Global and subscale scores were similar in survivors and non-survivors. Mean 1- and 3-month Global and emotional subscale and mean 1-month social subscale change scores decreased more in non-survivors than survivors. Compared with patients whose Global MacNew HRQL scores improved at one month, 4-year all-cause mortality hazard ratio (HR) was higher in patients whose HRQL deteriorated (HR, 1.70, 95% CI, 1.09, 2.65; p=0.021). Compared with patients whose Global MacNew HRQL improved at three months, 4-year all-cause mortality was higher in both patients whose HRQL had deteriorated (HR, 2.07, 95% CI, 1.29, 3.32; p=0.003) and patients with unchanged HRQL (HR, 2.62, 95% CI, 1.11, 6.17; p=0.028).\Question: Does change in health-related quality of life in patients with coronary artery disease predict 4-year mortality?

SOLUTION:
A deterioration of ≥0.50 points in MacNew HRQL Global scores at both one and three months is predictive of 4-year all-cause mortality. Serial HRQL information may be useful to identify patients at higher risk for adverse cardiac events and mortality and may have implications for determining follow-up frequency and treatment in individual patients.