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.

Ex Input:
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).

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


Ex Input:
Allopregnanolone (3α-hydroxy-5α-pregnan-20-one) is a neurosteroid which has an inhibitory function through interaction with the GABAA receptor. This progesterone metabolite has strong sedative and anxiolytic properties, and low endogenous levels have been associated with depressed mood. This study aimed to investigate whether the very high serum allopregnanolone levels in late pregnancy covary with concurrent self-rated symptoms of depression and anxiety.', 'Ninety-six women in pregnancy weeks 37-40 rated symptoms of depression and anxiety with the Montgomery-Åsberg Depression Rating Scale (MADRS-S) and Spielberger State-Trait Anxiety Inventory. Their serum allopregnanolone was analyzed by Celite chromatography and radioimmunoassay.', "Ten women had elevated depression scores (MADRS-S ≥ 13), and this group had significantly lower allopregnanolone levels compared to women with MADRS-S scores in the normal range (39.0 ± 17.9 vs. 54.6 ± 18.7 nmol/l, p = 0.014). A significant negative correlation was found between self-rated depression scores and allopregnanolone concentrations (Pearson's correlation coefficient = -0.220, p = 0.031). The linear association between self-rated depression scores and allopregnanolone serum concentrations remained significant when adjusted for gestational length, progesterone levels, and parity. Self-rated anxiety, however, was not associated with allopregnanolone serum concentrations during pregnancy.

Ex Output:
Is low serum allopregnanolone associated with symptoms of depression in late pregnancy?


Ex Input:
Inspired by the limited facility of the Penn classification, the authors aimed to determine a rapid and optimal preoperative assessment tool to predict surgical mortality after acute Stanford type-A aortic dissection (AAAD) repair.', 'Patients who underwent an attempted surgical repair of AAAD were determined using a de-identified single institution database. The charts of 144 patients were reviewed retrospectively for preoperative demographics and surrogates for disease severity and malperfusion. Bivariate analysis was used to determine significant (p≤0.05) predictors of in-hospital and 1-year mortality, the primary endpoints. Receiver operating characteristic curve generation was used to define optimal cut-off values for continuous predictors.', 'Single center, level 1 trauma, university teaching hospital.', 'The study included 144 cardiac surgical patients with acute type-A aortic dissection presenting for surgical correction.', 'Surgical repair of aortic dissection with preoperative laboratory samples drawn before patient transfer to the operating room or immediately after arterial catheter placement intraoperatively.', 'The study cohort comprised 144 patients. In-hospital mortality was 9%, and the 1-year mortality rate was 17%. Variables that demonstrated a correlation with in-hospital mortality included an elevated serum lactic acid level (odds ratio [OR] 1.5 [1.3-1.9], p<0.001), a depressed ejection fraction (OR 0.91 [0.86-0.96], p = .001), effusion (OR 4.8 [1.02-22.5], p = 0.04), neurologic change (OR 5.3 [1.6-17.4], p = 0.006), severe aortic regurgitation (OR 8.2 [2.0-33.9], p = 0.006), and cardiopulmonary resuscitation (OR 6.8 [1.7-26.9], p = 0.01). Only an increased serum lactic acid level demonstrated a trend with 1-year mortality using univariate Cox regression (hazard ratio 1.1 [1.0-1.1], p = 0.006). Receiver operating characteristic analysis revealed optimal cut-off lactic acid levels of 6.0 mmol/L and 6.9 mmol/L for in-hospital and 1-year mortality, respectively.

Ex Output:

Does hyperlactemia predict Surgical Mortality in Patients Presenting with Acute Stanford Type-A Aortic Dissection?