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 Q]: Context: Gastric lipase is an important enzyme for dietary triglyceride digestion in normal subjects. Its regulation is unknown, as is the relation between the quantity and activity of the enzyme.', 'In a dose-response study we investigated the effect of low doses of pentagastrin (less than 1000 ng/kg/h) on the output of gastric lipase measured by a kinetic assay and an enzyme-linked immunosorbent assay (ELISA).', 'In five healthy volunteers stepwise intravenous pentagastrin infusions of 0, 50, 100, 500, and 1000 ng/kg/h resulted in a stepwise increase in the lipase output, as measured with ELISA. However, the lipolytic activity, measured with a kinetic assay, decreased as the pH of the gastric contents decreased.
Answer: We conclude that secretion of the gastric lipase is stimulated by pentagastrin, but the simultaneous secretion of acid counteracts the lipolytic activity of the enzyme when food is not present.
[EX A]: Do low doses of pentagastrin stimulate gastric lipase secretion in man?

[EX Q]: Context: Serum ghrelin levels are elevated in uremic patients. However, no data are available on the relationship between metabolic syndrome and serum ghrelin levels in peritoneal dialysis (PD) patients.', 'Metabolic syndrome and its components were defined using diagnostic criteria recommended by the International Diabetes Federation. Fasting serum samples were taken from 30 PD patients. Serum ghrelin levels were measured by using a commercial enzyme-linked immunosorbent assay kit.', 'Of the 30 PD patients, 53.3% (16/30) had metabolic syndrome. Fasting serum ghrelin corrected inversely with metabolic syndrome among these PDs patients (p = 0.002). By odds ratio (OR) analysis of metabolic syndrome and metabolic syndrome diagnostic criteria, the predictors for metabolic syndrome are fasting glucose [OR: 39.00; 95% confidence interval (CI): 3.80 to 399.85; p < 0.001], triglycerides (OR: 37.50; 95% CI: 3.64 to 386.51; p < 0.001), and waist circumference (OR: 4.20; 95% CI: 1.95 to 9.03; p < 0.001). Univariate linear regression analysis showed that body weight (r = -0.461, p = 0.010), waist circumference (r = -0.390, p = 0.033), and body mass index (r = -0.438, p = 0.016) were negatively correlated with serum ghrelin, and serum high density lipoprotein [HDL (r = 0.626, p < 0.001)] was positively correlated with serum ghrelin. Multivariate forward stepwise linear regression analysis of the significant variables showed that HDL (R(2) change = 0.392; p < 0.001) was the independent predictor of serum ghrelin in PD patients and explained 39.2% of the variance.
Answer: These results indicate an inverse association between circulating fasting ghrelin and metabolic syndrome in PD patients. Serum HDL was associated with serum ghrelin among PD patients.
[EX A]: Is fasting serum ghrelin level associated with metabolic syndrome in peritoneal dialysis patients?

[EX Q]: Context: Extracorporeal circulation is routinely used in thoracoabdominal aortic aneurysm repair to preserve blood perfusion. Despite this protective measure, acute and chronic kidney disorders can develop. Therefore, the aim of this study was to establish a new large-animal model to assess the efficacy of selective renal perfusion (SRP) with extracorporeal circulation in a setting of thoracoabdominal aortic aneurysm repair.', 'Eighteen pigs underwent a thoracolaparotomy, during with the aorta and renal arteries were exposed. The animals were divided into three cohorts of six pigs each: cohort I--control; cohort II--thoracic aortic clamping with distal aortic perfusion (DAP) using a roller pump; and cohort III--thoracic aortic clamping with DAP plus SRP. Kidney metabolism, kidney injury, and red blood cell damage were measured by oxygen extraction ratio (O2ER), neutrophil gelatinase-associated lipocalin, a marker for acute kidney damage, and serum free hemoglobin.', 'With normal mean arterial blood pressures, flow rates in the renal arteries during perfusion decreased to 75% (group II) with DAP and to 50% (group III) with SRP compared with the control animals (group I; P = .0279 for I vs II; P = .0002 for I vs III). Microcirculation, measured by microspheres, did not differ significantly among the groups. In contrast, O2ER (P = .0021 for I vs III) and neutrophil gelatinase-associated lipocalin (P = .0083 for I vs III) levels were significantly increased in group III, whereas free hemoglobin was increased in groups II and III (P = .0406 for I vs II; P = .0018 for I vs III).
Answer: SRP with a roller pump induces kidney tubule injury. Thus, distal aortic and SRP in our model does not provide adequate kidney protection. Furthermore, the perfusion system provokes red blood cell damage with increased free hemoglobin. Hence, the SRP perfusion technique should be revised and tested.
[EX A]:
Does selective renal blood perfusion induce renal tubules injury in a porcine model?