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.
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Question: Pathologic change in Alzheimer disease (AD) begins some years before symptoms. MRS has the potential to detect metabolic abnormalities reflecting this early pathologic change. Presenilin 1 (PS1) and amyloid precursor protein (APP) mutation carriers have a nearly 100% risk of developing AD and may be studied prior to symptom onset.', 'Short echo time proton MR spectra were acquired from a midline posterior cingulate voxel in presymptomatic carriers of PS1 or APP mutations ("presymptomatic mutation carriers" [PMCs]; n = 7) and age- and sex-matched control subjects (n = 6). Ratios of N-acetyl aspartate (NAA), myo-inositol (MI), and choline-containing compounds (Cho) to creatine (Cr) were measured and NAA/MI calculated. Regression analyses and t tests were performed after log transformation.', 'PMC and control subjects were matched for age and sex. PMC subjects were 1.7 to 21.6 years (mean 9.8 years) before expected symptom onset, predicted from family-specific mean age at onset. Age did not significantly affect metabolite ratios. Geometric mean ratios in control subjects were as follows: NAA/Cr = 1.75, MI/Cr = 0.59, and NAA/MI = 2.95. NAA/Cr and NAA/MI were significantly reduced in PMC relative to controls (NAA/Cr mean decrease 10% [95% CI 2 to 18%]; NAA/MI mean decrease 25% [95% CI 3 to 44%]). MI/Cr was increased in PMC, but the differences did not achieve significance (19% increase [95% CI 1% decrease to 41% increase]; p = 0.07)). In PMCs, reduction in NAA/MI (p = 0.001) and MI/Cr (p = 0.002) were related to proximity of expected age at onset.

Answer: Does mRS show abnormalities before symptoms in familial Alzheimer disease?

Question: 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.

Answer: Does acetaldehyde inhibit the formation of retinoic acid from retinal in the rat esophagus?

Question: Recent studies evaluated the disease-modifying properties of lithium in mild cognitive impairment and dementia. Although potentially effective for these purposes, chronic lithium use in regard to safety in the elderly needs to be better explored.', 'To evaluate the effect of long-term lithium treatment at subtherapeutic doses on renal function in older adults. Secondary aims were to evaluate the clinical safety and tolerability of this treatment and its effects on thyroid, immune, and glycemic functions.', 'Between February 2007 and October 2011, a 2-year randomized, double-blind, placebo-controlled trial followed by a single-blinded phase for an additional 2 years. Sixty-one patients with mild cognitive impairment (Mayo Clinic criteria) were randomized to receive lithium or placebo. Renal function was estimated by the abbreviated Modification of Diet in Renal Disease (aMDRD) and the Chronic Kidney Disease-Epidemiology study (CKD-EPI) equations. Leukocytes, serum thyroid-stimulating hormone (TSH) and free thyroxine (T), and serum glucose and insulin were determined. Tolerability was evaluated at 3-month intervals through systematic clinical examinations and by the UKU Side Effect Rating Scale.', 'Analysis of longitudinal regression indicated that no significant changes in renal function were detected by the aMDRD (P = .453) and CKD-EPI (P = .213) equations after 4 years of lithium treatment. Significant increases in the number of neutrophils (P = .038), serum TSH (P = .034), and body weight (P = .015) were observed in the lithium group. The lithium group presented more overall adverse events (P = .045), particularly interfering in daily activities (P < .001). In addition, those patients had a higher incidence of diabetes mellitus (P = .037) and arrhythmia (P = .028).

Answer:
Does long-term , low-dose lithium treatment impair renal function in the elderly : a 2-year randomized , placebo-controlled trial followed by single-blind extension?