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.

[EX Q]: Context: The purpose of this study was to investigate the ability of neutrophil gelatinase-associated lipocalin (NGAL), cystatin C, and their combination in predicting the duration and severity of acute kidney injury (AKI) after cardiac surgery in adults.', 'Using data from a prospective observational study of 100 adult cardiac surgical patients, we correlated early postoperative concentrations of plasma NGAL and serum cystatin C with the duration (time during which AKI persisted according to the Acute Kidney Injury Network criteria) and severity of AKI (change in serum creatinine) and with length of stay in intensive care.', 'We found a mean AKI duration of 67.2 +/- 41.0 hours which was associated with prolonged hospitalization (p < 0.001). NGAL, cystatin C, and their combination on arrival in intensive care correlated with subsequent AKI duration (all p < 0.01) and severity (all p < 0.001). The area under the receiver operating characteristic curve for AKI prediction was 0.77 (95% confidence interval: 0.63 to 0.91) for NGAL and 0.76 (95% confidence interval: 0.61 to 0.91) for cystatin C on arrival in intensive care. Both markers also correlated with length of stay in intensive care (p = 0.037; p = 0.001). Neutrophil gelatinase-associated lipocalin and cystatin C were independent predictors of AKI duration and severity and of length of stay in intensive care (all p < 0.05). The value of cystatin C on arrival in intensive care appeared to be due to a carry-over effect from preoperative values.\Question: Do novel biomarkers early predict the severity of acute kidney injury after cardiac surgery in adults?
[EX A]: Immediately postoperatively, NGAL and cystatin C correlated with and were independent predictors of duration and severity of AKI and duration of intensive care stay after adult cardiac surgery. The combination of both renal biomarkers did not add predictive value.

[EX Q]: Context: Chronic pancreatitis (CP) and pancreatic cancer (PCa) are characterized by intrapancreatic neuropathic alterations, including increased neural density and hypertrophy, pancreatic neuritis and neural invasion (NI) by cancer cells in PCa. The aim of this study was to identify the influence of these neuropathic changes on the quality of pancreatic innervation, intrapancreatic glia, and visceral pain.', 'Pancreatic nerve fiber qualities were characterized by immunohistochemical visualization of various markers, including those for sympathetic (tyrosine hydroxylase, TH) and cholinergic innervation (choline acetyltransferase, ChAT), as well as the glial transcription factor, Sox10, and the neuroepithelial progenitor cell marker, Nestin, in normal pancreas (NP, n=16), CP (n=20), and PCa (n=20) patients. The neural immunoreactivity scores of these markers were correlated with the severity of intrapancreatic neuropathic changes and with abdominal pain sensation of patients.', 'Pancreatic sympathetic innervation was significantly reduced in CP and PCa, whereas parasympathetic innervation did not show major changes. Nestin neuro-immunoreactivity was stronger, and Sox10-immunoreactivity was weaker in CP and PCa than in NP. Pancreatic sympathetic and cholinergic innervation was noticeably decreased in patients with severe pancreatic neuritis, NI by cancer cells, or abdominal pain. Moreover, the neural immunoreactivity for Sox10 and Nestin also varied with intrapancreatic neuropathic alterations and abdominal pain.\Question: Does pancreatic neuropathy result in `` neural remodeling '' and altered pancreatic innervation in chronic pancreatitis and pancreatic cancer?
[EX A]: The quality of intrapancreatic nerve fibers and the activation state of intrapancreatic glia in CP and PCa are strikingly different from those in normal pancreas. This novel phenomenon of "neural remodeling" shows how pancreatic neuropathic pain and "visceral neuropathy" are associated with altered pancreatic innervation in CP and PCa.

[EX Q]: Context: To examine the utility of four criteria for distinguishing aortic from mitral valve prostheses on supine anteroposterior (AP) chest x rays in critically ill patients.', 'Two reviewers independently examined the post operative chest X-rays (CXR) of all patients undergoing either an aortic or mitral valve replacement over a 32 month period, in a blinded fashion. They applied four criteria to each film. For each criterion a sensitivity and specificity of differentiating the valve positions correctly was calculated for each reviewer, as well as a kappa statistic for inter-observer agreement between the two reviewers.', "Two hundred and twenty seven CXR's were evaluated by each of the reviewers. There were 174 aortic and 53 mitral valve replacements. There was a high level of inter-observer agreement for all four criteria applied (kappa values 0.785 to 0.966). Criterion one (imaginary line method) could be applied by both reviewers to less than 50% of CXR's, and when applied was specific but not sensitive. The other three criteria could be applied by both reviewers to approximately 80% of films. Criterion 2 (orientation method) was sensitive but not specific. Criteria 3 (valve orifice method) and 4 (perceived direction of blood flow method) were both highly sensitive and specific and are therefore the best methods.\Question: Is the imaginary line method reliable for identification of prosthetic heart valves on AP chest radiographs?
[EX A]:
The well known imaginary line method is of limited value when identifying prosthetic valve positions on supine AP CXR's. We advocate the use of the "valve orifice" method or the "perceived direction of blood flow" method to gain valuable information regarding the presence and position of prosthetic heart valves.