instruction:
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.
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Context: To investigate the incidence of acute kidney injury after cardiac surgery and its association with mortality in a patient population receiving ibuprofen and gentamicin perioperatively.', 'Retrospective study with Cox regression analysis to control for possible preoperative, intraoperative and postoperative confounders.', 'University hospital-based single-center study.', 'All patients who underwent coronary artery bypass grafting ± valve surgery during 2012.', 'None.', 'Acute surgery within 24 hours of coronary angiography, previous nephrectomy, preoperative sCr >2.26 mg/dL and selective cerebral perfusion during cardiopulmonary bypass were used as exclusion criteria. Acute kidney injury was defined, using the Acute Kidney Injury Network (AKIN) criteria. Six hundred eight patients were included in the study. Mean age was 68.2 ± 9.7 years, and 81% were males. Acute kidney injury was seen in 28.1% of the patients. Overall mortality at one year was 7% and 3% in the no-AKI group. At one year, mortality was 15% in patients with AKIN stage 1 and AKIN stage 2 compared to 70% in AKIN stage 3. A hazard ratio of 2.34 (95% CI: 1.21-4.51, p = 0.011) and 5.62 (95% CI: 2.42-13.06), p<0.0001) were found for AKIN stage 1 and 2/3 combined, respectively.\Question: Is acute kidney injury independently associated with higher mortality after cardiac surgery?
answer:
More than 28% of the patients undergoing elective or subacute cardiac surgery developed AKI in this contemporary cohort. Furthermore, acute kidney injury was an independent predictor of increased mortality irrespective of the perioperative risk factors.


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Context: Next-generation sequencing (NGS) allows for sampling numerous viral variants from infected patients. This provides a novel opportunity to represent and study the mutational landscape of Hepatitis C Virus (HCV) within a single host.', 'Intra-host variants of the HCV E1/E2 region were extensively sampled from 58 chronically infected patients. After NGS error correction, the average number of reads and variants obtained from each sample were 3202 and 464, respectively. The distance between each pair of variants was calculated and networks were created for each patient, where each node is a variant and two nodes are connected by a link if the nucleotide distance between them is 1. The work focused on large components having > 5% of all reads, which in average account for 93.7% of all reads found in a patient.\Question: Does next-generation sequencing reveal large connected networks of intra-host HCV variants?
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Most intra-host variants are organized into distinct single-mutation components that are: well separated from each other, represent genetic distances between viral variants, robust to sampling, reproducible and likely seeded during transmission events. Facilitated by NGS, large components offer a novel evolutionary framework for genetic analysis of intra-host viral populations and understanding transmission, immune escape and drug resistance.


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Context: MicroRNA-222 (miR-222) has been shown to play a potential oncogenic role in bladder cancer. The aim of this study was to evaluate the expression of miR-222 in bladder cancer and its potential relevance to clinicopathological characteristics and patient survival.', 'Surgical specimens of cancer tissue and adjacent normal tissue were obtained from 97 patients with bladder cancer. The relative expression levels of miR-222 in the cancer and the normal adjacent tissue were measured by quantitative reverse-transcriptase PCR. We analyzed their correlation with clinicopathological parameters and prognostic value.', 'The expression level of miR-222 was significantly higher in tumor tissues than in corresponding non-cancerous tissues (5.46\u2009±\u20091.45 versus 1.92\u2009±\u20090.65, P\u2009< \u20090.0001), and a high expression of miR-222 was found to be significantly associated with tumor grade (P\u2009=\u20090.003) and tumor stage (P\u2009=\u20090.005). The miR-222 expression level was classified as high or low in relation to the median value (cutoff value\u2009=\u20095.15). Kaplan-Meier analysis showed that patients with higher levels of miR-222 had significantly poorer survival than those with lower expression of this miRNA in patients, with a 5-year overall survival of 29.53% and 52.75%, respectively (P\u2009=\u20090.0034). In the multivariate Cox proportional hazards analysis, which included miR-222 level, tumor grade, tumor stage, and tumor number, high miR-222 expression was independently associated with poor survival (P\u2009<\u20090.001; hazard ratio 6.17; 95% CI 2.33 to 10.39).\Question: Is increased expression of miR-222 associated with poor prognosis in bladder cancer?
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miR-222 overexpression is involved in the poor prognosis of bladder cancer and can be used as a biomarker for selection of cases requiring special attention.