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.

[EX Q]: 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?
[EX A]: 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.

[EX Q]: Context: Acute kidney injury (AKI) is an established indicator of all-cause mortality in a coronary care unit (CCU), and evaluating the risks of renal dysfunction can guide treatment decisions. In this study we used the Society of Thoracic Surgeons (STS) score to predict the incidence of AKI in CCU patients who had not undergone coronary artery bypass surgery (CABG) after a cardiac angiogram.', 'The study cohort comprised 126 patients diagnosed with 2 or 3 coronary vessels disease who did not receive CABG during their hospital course. This study was performed in the CCU of a tertiary referral university hospital between September 2012 and August 2013. The STS score was evaluated with adjustment in all patients and the outcomes of the risk of mortality, morbidity, or mortality and renal failure were selected for predicting assessment. Furthermore, the performance of the STS scores was compared with that of other scoring systems.', 'A total of 28.5% (36 of 126) of the patients had AKI of varying severity. For predicting AKI, the STS renal failure score was excellent, with areas under the receiver operating characteristic curve of 0.851 ± 0.039, p < 0.001. When compared with other scoring systems, the STS renal failure score demonstrated the highest discriminatory power, the most favorable Youden index, and the highest overall correctness of prediction.\Question: Do society of Thoracic Surgeons score predicts kidney injury in patients not undergoing bypass surgery?
[EX A]: The STS score is an effective tool for predicting AKI in patients with coronary artery disease who have not undergone CABG. Frequent monitoring of serum creatinine level or early application of AKI biomarkers are warranted for STS renal failure 5.7% or greater.

[EX Q]: Context: It has been shown that the selective 5-HT4 receptor agonist tegaserod induces an increase in frequency and amplitude of contractions in isolated muscle preparations of equine ileum and pelvic flexure.', 'To investigate the effects of tegaserod on gut motility and transit of spheres in normal horses.', 'Six mature Freiberger horses were kept under standardised conditions. Effects of tegaserod (0.02 mg/kg bwt i.v. b.i.d. for 2 days) or vehicle on intestinal transit of barium-filled spheres, defaecation and gut sounds were studied in a cross-over design. Spheres were given via stomach tube prior to the first dosing of tegaserod or vehicle. Faeces were collected every 3 h and spheres eliminated were identified radiologically in the faeces.', 'Tegaserod significantly accelerated the gastrointestinal (GI) transit time of spheres and increased the frequency of defaecation and scores of gut sounds compared to vehicle. The compound was well tolerated; no effects on behaviour, body temperature, heart rate, respiratory rate and clinical laboratory data were observed.\Question: Does tegaserod ( HTF 919 ) stimulate gut motility in normal horses?
[EX A]:
Tegaserod efficaciously stimulated motility and accelerate GI transit in healthy horses.

