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.

Context: Although the presence of perineural invasion has been recognized as a poor prognostic factor in extrahepatic cholangiocarcinoma, the molecular mechanisms of perineural invasion in extrahepatic cholangiocarcinoma remain unclear. Nerve growth factor has been reported to be a candidate predictive biomarker of perineural invasion in some cancers.', 'To investigate the impact of intratumoral nerve growth factor expression in resected extrahepatic cholangiocarcinoma on survival.', 'Intratumoral nerve growth factor expression was investigated immunohistochemically in 112 patients with resected extrahepatic cholangiocarcinoma. Associations between nerve growth factor expression and clinicopathological factors were statistically evaluated, and risk factors for poor survival were analyzed using univariate and multivariate analyses.', 'High and low nerve growth factor expression was observed in 62 (55%) and 50 (45%) patients, respectively. For all 112 patients, no significant correlation was found between nerve growth factor expression and presence of perineural invasion (P = 0.942). Moreover, nerve growth factor expression was not associated with recurrence-free survival (P = 0.861) and overall survival (P = 0.973). In multivariate analysis, lymph node metastasis (P = 0.004) was identified as an independent risk factor for early recurrence and the presence of perineural invasion (P = 0.002) and lymph node metastasis (P < 0.001) was identified as independent risk factors for poor survival.
Answer: Intratumoral nerve growth factor expression is not associated with perineural invasion or recurrence-free and overall survival in patients with resected extrahepatic cholangiocarcinoma.
Is nerve Growth Factor Expression Associated with Perineural Invasion in Extrahepatic Cholangiocarcinoma?

Context: To determine the prevalence of five physical frailty phenotype components and to assess the relationship between them and other clinical factors.', "A population-based cross-sectional study was performed. Subjects 75 years and older were randomly selected from primary care databases (with sampling stratified by gender). Physical frailty phenotypes were assessed using Fried's criteria. Sociodemographic data, comorbidities, nutritional status, and functional capacity were assessed.", '126 subjects were recruited (47% women). Prevalence rates were poor muscle strength: 50%; low physical activity: 29%; slow gait: 28%; exhaustion: 27%; and weight loss: 5%. Prefrailty and frailty prevalence rates were 35.7% and 29.4%, respectively. Poor muscle strength and low physical activity showed a close relationship and concordance (kappa = 0.92). Most frailty components were associated with outdoor activity, hours walked daily, and certain comorbidities.
Answer: Poor muscle strength was the most prevalent frailty component and was closely associated with physical activity, suggesting that training programs may revert or prevent the frailty process.
Do poor Muscle Strength and Low Physical Activity Are the Most Prevalent Frailty Components in Community-Dwelling Older Adults?

Context: In some subjects with suspected asthma who have normal spirometry, administration of bronchodilators (BD) improves expiratory flow rates. The predictive value of this phenomenon in adults is not known.', 'To evaluate the predictive value of the response to BD for bronchial hyper-responsiveness (BHR) using the metacholine challenge test (MCT). Patients and methods. The study population included 62 non-smoking adult patients (41.9% women) 29.5 +/- 15.5 years of age (range 18-64 years) with suspected asthma with normal spirometry that underwent MCT within 1 week. The response to BD (200 mu g inhaled salbutamol) was compared between subjects with positive and negative MCT using cutoff levels of provocative concentrations of metacholine causing a 20% decrease in forced expiratory volume in 1 second (FEV(1)) (PC(20)) of 4 and 8 mg/mL.', 'Mean (+/- SD) baseline FEV(1) was 87.8 +/- 12% of predicted. After BD administration the mean FEV(1) increased by 4.3 +/- 3.9%. The prevalence of BHR was 17.7% and 25.8% for PC(20) for PC(20) of 4 mg/mL and 8 mg/mL, respectively. The post-BD FEV(1) increment for subjects with positive and negative MCT tests was 3.9% +/- 3.3% versus 4.4% +/- 4.1%, respectively; p = 0.89, using cutoff of 4 mg/mL. The corresponding figures for cutoff of 8 mg/ml were 4.3% +/- 3.1% vs. 4.3% +/- 4.2%, respectively; p = 0.8465. There was no correlation between post-BD FEV(1) increment and PC(20) values in patients with positive MCT test for the above-mentioned cutoff levels (correlation coefficient r = 0.1645, p = 0.6289; and r = 0.2417, p = 0.4051, respectively).
Answer: In adults with suspected asthma who have normal spirometry, the response to BD cannot be used to predict BHR.

Is the response to bronchodilators in adults predictive of bronchial-hyperreactivity?