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.
--------
Question: 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?

Answer: 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.


Question: Context: Abnormalities of serum sodium are common after subarachnoid hemorrhage (SAH) and have been linked to poor outcome. This study analyzed whether abnormal serum sodium levels are associated with cardiac outcomes and mortality after subarachnoid hemorrhage (SAH).', "In a prospective cohort study of SAH patients, the primary predictor variable was subjects' sodium level. Hypernatremia was defined as sodium >143 mmol/L and hyponatremia was <133 mmol/L. Cardiac troponin I (cTi) was measured and echocardiography was performed on three study days. Dichotomous outcome variables were cTi > 1.0 microg/L, left-ventricular ejection fraction (LVEF) <50%, presence (vs absence) of regional wall motion abnormalities (RWMA) of the LV, pulmonary edema, and death. Additional analyses studied the degree of hypernatremia and sodium supplementation, and the temporal relationship between hypernatremia and cardiac outcomes.", 'The study included 214 subjects. Forty-eight subjects (22%) were hypernatremic on at least one study day, and 45 (21%) were hyponatremic. After multivariate adjustment, hypernatremia was an independent predictor of LVEF <50% (OR 4.7, CI 1.3-16.2, p = 0.015), elevated cTi (OR 3.7, CI 1.2-11.9, p = 0.028), and pulmonary edema (OR 4.1 CI 1.4-1.5, p = 0.008). It was not, however a statistically significant predictor of mortality (p = 0.075).\Question: Does hypernatremia predict adverse cardiovascular and neurological outcomes after SAH?

Answer: In the acute period after SAH, hypernatremia is associated with adverse cardiac outcomes and death. SAH patients with hypernatremia should be monitored for evidence of cardiac dysfunction.


Question: Context: To assess prospectively the impact of psychiatric disorders on risk for exacerbations. The course of chronic obstructive pulmonary disease (COPD) is punctuated by acute exacerbations. Although anxiety and mood disorders are common in patients with COPD, no studies have assessed prospectively the association between these disorders and exacerbations.', "Psychiatric disorders were evaluated by a structured psychiatric interview in 110 patients (51% women, age (mean +/- standard deviation) = 66 +/- 8 years) with stable COPD and previous admission for exacerbations recruited from two outpatient clinics. Patients were followed for a mean of 2 years and both inpatient-treated (i.e., treated in the emergency department or hospital) and outpatient-treated (i.e., treated with medication in the patient's own environment) exacerbations were recorded.", 'Independent of covariates, patients with psychiatric disorders exhibited a significantly higher weighted annual rate of exacerbations treated in an outpatient setting after adjustment for covariates (3 versus 2, p = .003) than patients without psychiatric disorders, but no difference in exacerbations treated in the inpatient setting. They were also at a higher risk for any (relative risk (RR) = 1.56, 95% Confidence Interval (CI) = 1.02-2.37) and outpatient (RR = 1.68, 95% CI = 1.08-2.59) exacerbations, but not inpatient exacerbations (RR = 1.36, 95% CI = 0.82-2.25).\Question: Are chronic obstructive pulmonary disease patients with psychiatric disorders at greater risk of exacerbations?

Answer:
Patients with psychiatric disorders are at greater risk of exacerbations treated in an outpatient setting but not those treated in an inpatient setting. These outpatient-managed exacerbations account for a significant proportion of the healthcare burden for COPD, so interventions should target patients with psychiatric disorders to improve management of COPD.