Given a passage with a context and an answer, 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:
Context: Before desflurane is advocated for patients undergoing neurosurgical procedures, it is necessary to determine the effect of desflurane on cerebral blood flow (CBF). In this study, CBF values are compared between desflurane and isoflurane at two doses. In addition, CBF reactivity to CO2 and the effect of prolonged exposure were compared between the two agents.', 'Cerebral blood flow measurements with intravenous 133Xe were performed in 24 patients undergoing craniotomy for mass lesions, randomized to receive either isoflurane or desflurane in oxygen and air. Cerebral blood flow was determined at 1 and 1.5 MAC concentrations at PaCO2 of 25 mmHg in the absence of surgical stimulation. Intraoperatively, with 1.25 MAC anesthesia, CBF was determined at target PaCO2 of 25 and 35 mmHg. In 15 patients, an additional measurement at 1.25 MAC was made before closure.', 'At 1.0 MAC, mean +/- SD CBF values for the desflurane and isoflurane groups were 18 +/- 2 and 20 +/- 3 ml x 100 g-1 x min-1, respectively. At 1.5 MAC, CBF values were the same for the two anesthetics; 17 +/- 3 ml x 100 g-1 x min-1 for isoflurane and 19 +/- 4 ml.100 g-1 x min-1 for desflurane. During 1.25 MAC anesthesia, there were no differences between groups, with CO2 reactivity 1.3 +/- 1.2 ml x 100 g-1 x min-1 x mmHg-1 for desflurane and 1.6 +/- 0.6 ml.100 g-1 x min-1 x mmHg-1 for isoflurane. There was no demonstrable decrease in CBF with prolonged exposure to either agent.
Answer: Desflurane and isoflurane are similar in terms of absolute CBF, the response to increasing doses, and the preservation of CO2 reactivity.

Ex Output:
Do desflurane and isoflurane have similar effects on cerebral blood flow in patients with intracranial mass lesions?


Ex Input:
Context: Noninvasive pacemaker stress echocardiography is a newly introduced method for the diagnosis of coronary artery disease in patients with a permanent pacemaker. The prognostic value of pacemaker stress echocardiography has not been studied.', 'We studied 136 patients (mean age 64+/-12 years) with a permanent pacemaker who underwent pacemaker stress echocardiography for evaluation of coronary artery disease. All patients underwent pacemaker stress echocardiography by external programming (pacing heart rate up to ischemia or target heart rate).', 'Thirty-one patients (23%) had normal study results. Ischemia was detected in 75 patients (55%). During a mean follow-up of 3.5+/-2.4 years, 35 deaths (26%) (20 the result of cardiac causes) and 2 nonfatal myocardial infarctions (1%) occurred. The annual cardiac death rate was 1.3% in patients without ischemia and 4.6% in patients with ischemia (P=.01). The annual all-cause mortality rate was 3.1% in patients without ischemia and 7% in patients with ischemia (P=.004). The presence of ischemia during pacemaker stress echocardiography was the strongest independent predictor of cardiac death (hazard ratio 4.1, confidence interval 1.2-14.5) and all-cause mortality (hazard ratio 2.7, confidence interval 1.2-6.0) in a multivariable model.
Answer: Myocardial ischemia during pacemaker stress echocardiography is an independent predictor of cardiac death and all-cause mortality in patients with a permanent pacemaker.

Ex Output:
Does pacemaker stress echocardiography predict cardiac events in patients with permanent pacemaker?


Ex Input:
Context: Lieber-DeCarli diet has been used to induce obesity and non-alcoholic steatohepatitis (NASH). As scarce anatomical and clinical-related information on this diet model exists and being exercise an advised strategy to counteract metabolic diseases, we aimed to analyze the preventive (voluntary physical activity - VPA) and therapeutic (endurance training - ET) effect of exercise on clinical/anatomical features of rats fed with Lieber-DeCarli diet.', 'In the beginning of the protocol, Sprague-Dawley rats were divided into standard-diet sedentary (SS, n = 20), standard-diet VPA (SVPA, n = 10), high-fat diet sedentary (HS, n = 20) and high-fat diet VPA (HVPA, n = 10) groups. After 9-weeks, half (n = 10) of SS and HS groups were engaged in an ET program (8 wks/5 d/wk/60 min/day). At this time, a blood sample was collected for biochemical analysis. At the end of protocol (17-weeks) anatomic measures were assessed. Heart, liver, femur and visceral fat were weighted and blood was collected again. Liver section was used for histopathological examination.', 'At 17-weeks, high-fat diet increased visceral adiposity (HS vs. SS), which was counteracted by both exercises. However, ET was the only intervention able to diminished obesity-related measures and the histological features of NASH. Moreover, blood analysis at 9 weeks showed that high-fat diet increased ALT, AST, cholesterol and HDL while VLDL and TG levels were decreased (HS vs. SS). Notably, although these parameters were counteracted after 9-weeks of VPA, they were transitory and not observed after 17-weeks.
Answer: ET used as a therapeutic tool mitigated the clinical/anatomical-related features induced by Liber-DeCarli diet, thus possibly contributing to control obesity and metabolic disorders.

Ex Output:

Does physical exercise antagonize clinical and anatomical features characterizing Lieber-DeCarli diet-induced obesity and related metabolic disorders?