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 Q]: It has already been demonstrated that the rat esophagus produces retinoic acid from retinol. In this study, this process is further characterized and the effect of acetaldehyde examined to elucidate the possible mechanisms behind the epidemiological evidence that the incidence of esophageal cancer is higher in alcoholics.', 'Rat esophageal samples were incubated with all-trans retinal and newly formed all-trans retinoic acid (ATRA) was quantified using high-performance liquid chromatography (HPLC). Furthermore, beta-nicotinamide adenine dinucleotide (NAD)-dependent acetaldehyde oxidation by the rat esophagus was examined by tracing NAD reduction using a spectrophotometer.', 'Rat esophageal samples produced ATRA from all-trans retinal in a NAD-dependent manner and the potential was significantly attenuated by phenetyl isothiocynate, an ALDH inhibitor, or acetaldehyde depending on the concentration used. Rat esophageal samples also oxidized acetaldehyde of various concentrations NAD dependently. The ATRA formation potential that was temporarily inhibited by acetaldehyde was recovered to the control level by dialysis when the specimen was incubated with up to 50 microM of acetaldehyde.
[EX A]: Does acetaldehyde inhibit the formation of retinoic acid from retinal in the rat esophagus?

[EX Q]: Hypocalcemia is the most common complication after total thyroidectomy. Some patients need to stay in the hospital for monitoring of hypocalcemic symptoms and serum calcium levels for several days. We investigated the efficacy and safety of using early postoperative parathyroid hormone (PTH) results for early discharge after thyroidectomy.', 'A retrospective cohort study of 2 sequential groups of patients undergoing total thyroidectomy between January 2010 and March 2013 was undertaken. Patients were divided into 2 groups. In Group 1 (before June 2011), patients had daily monitoring of serum calcium level and hypocalcemic symptoms. They were discharged when calcium level was static and asymptomatic. Postoperative PTH was not utilized for discharge plan. In Group 2 (after June 2011), postoperative PTH and calcium level on day 1 were utilized to dictate subsequent management and discharge plan.', 'Of the 107 patients reviewed, 54 (50.5%) were in Group 1 and 53 (49.5%) were in Group 2. A total of 51 (47.7%) patients developed hypocalcemia. The two groups were comparable in demographic data, early postoperative PTH value, rate of hypocalcemia, the need for oral calcium and vitamin D supplements and rate of permanent hypoparathyroidism. Fewer patients in Group 2 experienced hypocalcemic symptoms, p=0.005. None of the patients in Group 2 needed intravenous calcium supplement (p=0.003). The median postoperative hospital stay for Group 1 was 4 days and for Group 2 was 1 day (p<0.0001).
[EX A]: Does postoperative PTH monitoring of hypocalcemia expedite discharge after thyroidectomy?

[EX Q]: In HCV-related graft hepatitis, immunosuppression has been implicated in rapid progression to cirrhosis, a serious clinical issue. We investigated the effects of cyclosporine or tacrolimus on cell growth and collagen production by hepatic stellate cells (HSC), which play a role in hepatic fibrosis.', 'Cultured rat HSCs and human HSC-derived TWNT-4 cells were evaluated for proliferation, type I collagen, phosphorylation states of mitogen-activated protein kinases extracellular signal-regulated kinase 1/2; [MAPKs Erk1/2], c-Jun N-terminal kinase (JNK, p38), as well as the expression of collagen, matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) genes.', 'Cyclosporine suppressed cell growth and collagen production in a concentration-dependent manner. At clinically relevant concentrations of 0.125 micromol (150 ng/mL) cyclosporine significantly reduced collagen production per cell by more than 50%. Similarly, tacrolimus also reduced both collagen concentration and cell number; however, tacrolimus at a clinically relevant concentration of 12.5 nmol (10 ng/mL) did not significantly reduce collagen production. Treatment with cyclosporine reduced type I collagen and TIMP-1 expression and enhanced MMP-1 expression. Cyclosporine also inhibited phosphorylation strongly for JNK and p38, and weakly inhibited for Erk1/2.
[EX A]:
Does cyclosporine suppress cell growth and collagen production in hepatic stellate cells?