TASK DEFINITION: Given a passage, 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.
PROBLEM: Apelin has been shown ex vivo to be a potent cardiac inotrope. This study was undertaken to evaluate the in vivo effects of apelin on cardiac function in native and ischemic cardiomyopathic rat hearts using a novel combination of a perivascular flow probe and a conductance catheter.', 'Native rats (n =32) and rats in heart failure 6 weeks after left anterior descending coronary artery ligation (n =22) underwent median sternotomy with placement of a perivascular flow probe around the ascending aorta and a pressure volume conductance catheter into the left ventricle. Compared with sham-operated rats, the ligated rats had significantly decreased baseline Pmax and max dP/dt. Continuous infusion of apelin at a rate of 0.01 microg/min for 20 minutes significantly increased Pmax and max dP/dt compared with infusion of vehicle alone in both native and failing hearts. Apelin infusion increased cardiac contractility, indicated by a significant increase in stroke volume (SV) without a change in left ventricular end diastolic volume (102+/-16% change from initial SV versus 26+/-20% for native animals, and 110+/-30% versus 26+/-11% for ligated animals), as well as an increase in preload recruitable stroke work (180+/-24 mm Hg versus 107+/-9 mm Hg for native animals).

SOLUTION: Does apelin have in vivo inotropic effects on normal and failing hearts?

PROBLEM: Diastolic runoff in the abdominal aorta, with subsequent circulatory mesenteric insufficiency, has been postulated as a cause of necrotizing enterocolitis in term infants with congenital heart disease. With this study we sought to determine whether Doppler-flow characteristics in the abdominal aorta can predict which infants are at specific risk, independent of gestational age and type of congenital heart disease.', 'We conducted a case-control study of term infants with congenital heart disease and proven necrotizing enterocolitis (n = 18) compared with gestational age-matched and diagnosis-matched control subjects (n = 20). Abdominal aortic Doppler velocities, time intervals, and reversals were analyzed. Groups were compared, and independent risk factors for necrotizing enterocolitis were determined.', 'The groups were similar with regard to weight, pulse pressure, use of prostaglandins or inotropes, presence of a patent ductus arteriosus, and systolic function. However, 47% of the case subjects with necrotizing enterocolitis had persistent retrograde diastolic flow in the abdominal aorta compared with 15% of the control subjects. When adjusting for multiple risk factors, persistent diastolic flow reversal remained the only factor significantly associated with necrotizing enterocolitis.

SOLUTION: Is persistent diastolic flow reversal in abdominal aortic Doppler-flow profiles associated with an increased risk of necrotizing enterocolitis in term infants with congenital heart disease?

PROBLEM: Regenerative endodontics aims to re-establish a functional pulp-dentin complex. First, the root canal system is disinfected primarily by irrigants and medicaments. Triple antibiotic paste (TAP), a commonly used intracanal medicament, has been shown to be directly toxic to stem cells at concentrations greater than 0.1 g/mL. Thus, its complete removal is a crucial step in regenerative endodontic procedures. We hypothesized that currently used irrigation techniques do not completely remove TAP from root canal system.', 'TAP was radiolabeled by the incorporation of I(125), and calcium hydroxide (Ultracal; Ultradent, South Jordan, UT) was radiolabeled with Ca(45). The intracanal medicaments were placed into standardized human root segments and incubated for 28 days at 37°C. Then, canals were irrigated with EndoActivator (Dentsply, Tulsa, OK), passive ultrasonic irrigation, EndoVac (SybronEndo, Coppell, TX), or a syringe/Max-i-Probe needle (Dentsply Rinn, Elgin, IL) using a standardized irrigation protocol in a closed system. Radioactivity levels (counts per minute values) were measured for each tooth before and after the irrigation protocols. Furthermore, the canals were sequentially enlarged and dentin samples collected and evaluated for radioactivity. Data were analyzed with analysis of variance and Bonferroni post hoc testing (P < .05).', 'Approximately 88% of the TAP was retained in the root canal system regardless of the irrigation technique used (no difference among groups). Furthermore, approximately 50% of the radiolabeled TAP was present circumferentially up to 350 μm within the dentin. Conversely, up to 98% of the radiolabeled intracanal calcium hydroxide was removed, and most residual medicament was found present in the initial 50 μm of dentin.

SOLUTION:
Do evaluation of triple antibiotic paste removal by different irrigation procedures?