TASK DEFINITION: In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.
PROBLEM: Context: This study was conducted to determine if there was an increase in the urinary excretion of fluoride, after the use of fluoride mouth rinses in children.', 'The sample consisted of 58 children aged 5-8 years, randomly selected, residents in non-fluoridated water areas. Urine samples were collected prior to mouthwash and also 2 hours after use. The control sample, which received no treatment, consisted of 16 children of equivalent age and from the same community. Urinary excretion of fluoride was analysed by determining the pH, creatinine, F- ion and fluoride (mg)/creatinine (g) (F/Cr) ratio in urine. Results In the studied sample, the mean F/Cr ratio before fluoride mouth rinse was 0.26 mg/g and it rose to 1.58 mg/g 2 hours after mouth rinse. This difference of 1.33 mg/g was statistically highly significant (p<.001). In the control group no significant changes occurred. The average 2 hours afterward F/Cr ratios were 0.29 and 0.27 respectively (p=0.426).\Question: Does renal excretion of fluoride after fluoride mouth rinse in children?

SOLUTION: After the use of a fluoride mouthwash, in children, there is a statistically significant increase of fluoride ion in urine, which can be attributed to the application of this product.

PROBLEM: Context: Perls' stain is routinely used to demonstrate iron in liver biopsies. We tested the hypothesis that it may be unnecessary in cases, where no iron or another similar pigment was seen on the routine hematoxylin and eosin (H and E) stained section.", "The aim of this study was to evaluate the efficiency of H and E stain in demonstrating iron in liver biopsies as well as to determine the possibility of replacing Perls' stain with H and E stain.", "Two hundred pairs of slides of liver biopsies were taken from the archival files of the Department of Pathology from 2006 to 2011. Perls' and H and E slides were independently reviewed for the presence of iron.", "Hundred and one cases showed the presence of iron using H and E stain. 84 of 86 cases showed positive iron using both Perls' and H and E stains. Seventeen cases were positive using H and E stain but negative with Perls'. Only two cases did not show the presence of iron using H and E stain. Ninety-seven cases were negative using both Perls' and H and E stains. H and E stain showed a sensitivity, specificity, accuracy, positive predictive valve, and negative predictive value of 97.67%, 85.08%, 90.5%, 83.16%, and 97.98%, respectively.\Question: Do hematoxylin and eosin stain shows a high sensitivity but sub-optimal specificity in demonstrating iron pigment in liver biopsies?

SOLUTION: We demonstrate that the H and E stain is a sensitive method to detect iron pigment in liver biopsies, particularly when present in large quantities. A negative H and E stain might obviate the need for extra Perls' staining, thus saving costs and shortening report turn-around times.

PROBLEM: Context: The aim of this study was to compare the clinical characteristics of patients enrolled in randomized clinical trials on congestive heart failure treatment with those of real-world patients encountered in daily clinical practice.', 'We searched the Cochrane review methodology, Medline and SilverPlatter databases to obtain the clinical characteristics of both patients enrolled in therapeutic clinical trials and real-world patients with heart failure. We selected 27 clinical trials, and 8 prospective epidemiological studies or registries published between 1987 and 2001 which enrolled 53,859 and 18,207 patients, respectively.', 'On average, compared to real-world heart failure patients, patients enrolled in clinical trials were younger (63 +/- 10 vs 75 +/- 11 years respectively, p < 0.0001), and more likely to be male (72 vs 54% respectively, p < 0.0001). Clinical trial patients showed a lower ejection fraction (26 +/- 7 vs 38 +/- 15% respectively, p < 0.0001) but a lower prevalence of NYHA functional class III-IV (62 vs 75% respectively, p < 0.0001) than real-world patients. In clinical trial patients, the prevalence of ischemic heart disease (67 vs 42% respectively, p < 0.0001) and a history of previous myocardial infarction (62 vs 42% respectively, p < 0.0001) were higher than in real-world patients. Conversely, the prevalence of chronic atrial fibrillation (12 vs 31% respectively, p < 0.0001) and of diabetes (22 vs 24% respectively, p < 0.02) was lower in trial patients than in real-world patients.\Question: Are patients with chronic heart failure encountered in daily clinical practice different from the `` typical '' patient enrolled in therapeutic trials?

SOLUTION:
Our data suggest that most clinical trials on congestive heart failure, on which the guidelines for clinical practice are based, have generally included patients who are not representative of the whole spectrum of patients actually managed in clinical practice.