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 Input:
Context: Chromatin epigenetics participate in control of gene expression during metazoan development. DNA methylation and post-translational modifications (PTMs) of histones have been extensively characterised in cell types present in, or derived from, mouse embryos. In embryonic stem cells (ESCs) derived from blastocysts, factors involved in deposition of epigenetic marks regulate properties related to self-renewal and pluripotency. In the germ lineage, changes in histone PTMs and DNA demethylation occur during formation of the primordial germ cells (PGCs) to reset the epigenome of the future gametes. Trimethylation of histone H3 on lysine 27 (H3K27me3) by Polycomb group proteins is involved in several epigenome-remodelling steps, but it remains unclear whether these epigenetic features are conserved in non-mammalian vertebrates. To investigate this question, we compared the abundance and nuclear distribution of the main histone PTMs, 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) in chicken ESCs, PGCs and blastodermal cells (BCs) with differentiated chicken ESCs and embryonic fibroblasts. In addition, we analysed the expression of chromatin modifier genes to better understand the establishment and dynamics of chromatin epigenetic profiles.', 'The nuclear distributions of most PTMs and 5hmC in chicken stem cells were similar to what has been described for mammalian cells. However, unlike mouse pericentric heterochromatin (PCH), chicken ESC PCH contained high levels of trimethylated histone H3 on lysine 27 (H3K27me3). In differentiated chicken cells, PCH was less enriched in H3K27me3 relative to chromatin overall. In PGCs, the H3K27me3 global level was greatly reduced, whereas the H3K9me3 level was elevated. Most chromatin modifier genes known in mammals were expressed in chicken ESCs, PGCs and BCs. Genes presumably involved in de novo DNA methylation were very highly expressed. DNMT3B and HELLS/SMARCA6 were highly expressed in chicken ESCs, PGCs and BCs compared to differentiated chicken ESCs and embryonic fibroblasts, and DNMT3A was strongly expressed in ESCs, differentiated ESCs and BCs.\Question: Do chicken embryonic stem cells and primordial germ cells display different heterochromatic histone marks than their mammalian counterparts?

Ex Output:
Chicken ESCs and PGCs differ from their mammalian counterparts with respect to H3K27 methylation. High enrichment of H3K27me3 at PCH is specific to pluripotent cells in chicken. Our results demonstrate that the dynamics in chromatin constitution described during mouse development is not universal to all vertebrate species.


Ex Input:
Context: To ascertain the prevalence of psychiatric symptoms and substance use disorders among adolescents with a lifetime history of foster care placement, using data from a nationally representative sample of U.S. adolescents.', 'We studied adolescents aged 12-17 years in the public use file of the 2000 National Household on Drug Abuse (n = 19,430, including 464 adolescents with history of foster care placement). Psychiatric symptoms and substance use disorders were ascertained through direct interviewing of adolescents. Logistic regression analyses were used to estimate the odds of past-year psychiatric symptoms and substance use disorders among adolescents involved with foster care, as compared to those without a lifetime history of foster care placement (comparison group).', 'Adolescents involved with foster care had more past-year psychiatric symptoms, and especially more conduct symptoms, and past-year substance use disorders than those never placed in foster care. Adolescents involved with foster care were about four times more likely to have attempted suicide in the preceding 12 months (adjusted odds ratio [AOR] 3.95; 95% confidence interval [CI] 2.78, 5.61), and about five times more likely to receive a drug dependence diagnosis in the same period (AOR 4.81; 95% CI 3.22, 7.18).\Question: Do psychiatric symptoms and substance use disorders in a nationally representative sample of American adolescents involved with foster care?

Ex Output:
Adolescents involved with foster care have a higher prevalence of psychiatric symptoms and drug use disorders than those never placed in foster care. Additionally, the results of this study suggest that they may be at elevated risk for suicide attempts.


Ex Input:
Context: Only a few small studies have evaluated risk factors related to early death following emergency surgery for colonic cancer. The aim of this study was to identify risk factors for death within 30 days after such surgery.', 'Some 2157 patients who underwent emergency treatment for colonic cancer from May 2001 to December 2005 were identified from the national colorectal cancer registry. Thirty-day mortality rates were calculated and risk factors for early death were identified using logistic regression analysis.', 'The overall 30-day mortality rate was 22.1 per cent. The strongest risk factor for early death was postoperative medical complications (cardiopulmonary, renal, thromboembolic and infectious), with an odds ratio of 11.7 (95 per cent confidence interval 8.8 to 15.5). Such complications occurred in 24.4 per cent of patients, of whom 57.8 per cent died. Other independent risk factors were age at least 71 years, male sex, American Society of Anesthesiologists grade III or more, palliative outcome, tumour perforation, splenectomy and adverse intraoperative surgical events. Postoperative surgical complications were noted in 20.4 per cent of the patients but had no statistically significant influence on mortality.\Question: Are postoperative medical complications the main cause of early death after emergency surgery for colonic cancer?

Ex Output:

Emergency surgery for colonic cancer is still associated with an increased risk of death. There is a need for a system providing increased safety in the perioperative period.