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: For the majority of congenital heart diseases (CHDs), the full complexity of the causative molecular network, which is driven by genetic, epigenetic, and environmental factors, is yet to be elucidated. Epigenetic alterations are suggested to play a pivotal role in modulating the phenotypic expression of CHDs and their clinical course during life. Candidate approaches implied that DNA methylation might have a developmental role in CHD and contributes to the long-term progress of non-structural cardiac diseases. The aim of the present study is to define the postnatal epigenome of two common cardiac malformations, representing epigenetic memory, and adaption to hemodynamic alterations, which are jointly relevant for the disease course.', 'We present the first analysis of genome-wide DNA methylation data obtained from myocardial biopsies of Tetralogy of Fallot (TOF) and ventricular septal defect patients. We defined stringent sets of differentially methylated regions between patients and controls, which are significantly enriched for genomic features like promoters, exons, and cardiac enhancers. For TOF, we linked DNA methylation with genome-wide expression data and found a significant overlap for hypermethylated promoters and down-regulated genes, and vice versa. We validated and replicated the methylation of selected CpGs and performed functional assays. We identified a hypermethylated novel developmental CpG island in the promoter of SCO2 and demonstrate its functional impact. Moreover, we discovered methylation changes co-localized with novel, differential splicing events among sarcomeric genes as well as transcription factor binding sites. Finally, we demonstrated the interaction of differentially methylated and expressed genes in TOF with mutated CHD genes in a molecular network.\Question: Does comparative DNA methylation and gene expression analysis identify novel genes for structural congenital heart diseases?
[EX A]: By interrogating DNA methylation and gene expression data, we identify two novel mechanism contributing to the phenotypic expression of CHDs: aberrant methylation of promoter CpG islands and methylation alterations leading to differential splicing.

[EX Q]: Context: Hyperoxia increases oxidative stress through the generation of reactive oxygen species and may therefore enhance inflammation in the lungs. The aim of this study was to investigate whether short term supplementary oxygen (28%) increases oxidative stress and inflammation in the airways by measuring 8-isoprostane and interleukin 6 (IL-6) concentrations in exhaled breath condensate.', 'Twenty three healthy subjects (12 men, mean (SD) age 48 (7) years) and 23 patients with chronic obstructive pulmonary disease (COPD; 15 men, mean (SD) age 56 (5) years) were studied. 8-isoprostane and IL-6 concentrations were measured by immunoassay.', 'Increased concentrations of 8-isoprostane and IL-6 were found in all subjects after breathing 28% oxygen for 1 hour. In healthy subjects the concentrations of 8-isoprostane and IL-6 were 10.9 (2.9) pg/ml and 4.9 (0.8) pg/ml, respectively, compared with baseline concentrations of 6.1 (1.3) pg/ml and 2.9 (0.6) pg/ml, and in patients with COPD the concentrations were 27.9 (3.1) pg/ml and 8.3 (1.2) pg/ml), respectively, compared with baseline concentrations of 18.9 (3.6) pg/ml and 6.3 (0.6) pg/ml. By contrast, breathing air through the same face mask for 1 hour had no significant effects on 8-isoprostane or IL-6 concentrations in normal subjects or those with COPD.\Question: Does supplementary oxygen in healthy subjects and those with COPD increase oxidative stress and airway inflammation?
[EX A]: These findings suggest that short term supplementary oxygen may enhance oxidative stress and inflammation in the airways. Whether this happens with long term oxygen therapy needs to be determined.

[EX Q]: Context: Previous reports have indicated an association between blood transfusion and prognosis of hepatocellular carcinoma (HCC) after hepatectomy. However, clinicopathological biases were not adjusted in these studies. We aimed to clarify the effect of blood transfusions in patients with HCC and Child-Pugh class A after hepatectomy by using inverse probability of treatment weighting (IPTW) analysis for selection bias control.', 'We enrolled 479 patients with primary HCC and Child-Pugh class A retrospectively (91 transfused and 388 nontransfused patients) who underwent curative hepatectomy. After adjusting for different covariate distributions for both groups by IPTW, we analyzed the prognostic outcomes.', 'In the unweighted analyses, overall survival (OS) rate of transfused patients was significantly lower than in nontransfused patients (P < 0.0001). Recurrence-free survival (RFS) rate of transfused patients was significantly lower than that of nontransfused patients (P = 0.0024). Multivariate analysis showed that blood transfusion was an independent prognostic factor of OS and RFS. The different distributive covariates between the two groups were age, presence of liver cirrhosis, serum level of alpha-fetoprotein, maximum tumor diameter, and amount of intraoperative blood loss. After IPTW by these covariates, OS rate of transfused patients was not significantly lower than those of nontransfused patients, whereas RFS rate of transfused patients remained significantly lower than those of nontransfused patients (P = 0.038, adjusted HR 1.45; 95% CI 1.0-2.1).\Question: Is blood transfusion associated with recurrence of hepatocellular carcinoma after hepatectomy in Child-Pugh class A patients?
[EX A]:
These results suggest that blood transfusion was associated with recurrence of HCC after hepatectomy in patients with HCC and Child-Pugh class A.