Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

[EX Q]: Context: Cardiac overexpression of the β-adrenoreceptor (βAR)-coupled stimulatory G-protein subunit Gαs enhances inotropic responses to adrenergic stimulation and improves survival in mice under βAR blockade. The authors recently identified three common haplotypes in the GNAS gene encoding Gαs, with the greatest Gαs protein expression and signal transduction in haplotype *3 carriers and less in haplotype *2 and *1 carriers. The authors tested the hypothesis that these GNAS variants result in altered mortality in patients after coronary artery bypass graft surgery, particularly in those receiving βAR blockade.', 'This prospective analysis included 1,627 European ancestry patients undergoing primary coronary artery bypass graft surgery. Patients were genotyped for two GNAS haplotype tagging single-nucleotide polymorphisms defining three major haplotypes. Up to 5-yr all-cause mortality was estimated using a Cox proportional hazard model; hazard ratios and 95% CIs were calculated while adjusting for demographics, clinical covariates, and the new EuroSCORE II.', 'Univariate analysis revealed haplotype-dependent 5-yr mortality rates (*1/*1: 18.9%, *2/*1: 13.7%, *2/*2: 9.3%, *3/*1: 10.6%, *3/*2: 9.1%, and *3/*3: 9.6%; P = 0.0006). After adjustment for other predictors of death, homozygote haplotype *1 carriers showed a doubled risk for death (hazard ratio, 2.2; 95% CI, 1.2 to 3.8; P = 0.006). Considering only patients receiving βAR blockers (n = 1,267), the adjusted risk of death even tripled (hazard ratio, 3.0; 95% CI, 1.5 to 6.1; P = 0.002).
Answer: GNAS haplotypes independently associate with an increased risk of death after primary coronary artery bypass graft surgery. These results are most pronounced in patients receiving βAR blockers, strengthening the rationale for personalized treatment, to decrease medication side effects and improve outcomes.
[EX A]: Do gNAS gene variants affect β-blocker-related survival after coronary artery bypass grafting?

[EX Q]: Context: Alterations in epigenetic processes are frequently noted in human disease. These epigenetic processes involve methylation of DNA and post-translational modifications of histones. It is well established that in particular histone methylation plays a key role in gene transcription. In this study, we have investigated the relationship between triple methylation of lysine 27 in histone H3 (H3K27Me3) modifications and atherosclerotic plaque stage.', '28 peri-renal aortic tissue patches covering the entire spectrum of atherosclerotic plaque development were evaluated by immunohistochemistry for the levels of H3K27Me3, EZH2, JMJD3 and BMI1.', 'The results of our studies are in support of a reduction in global levels of the H3K27Me3 modification in vessels with advanced atherosclerotic plaques. This reduction in H3K27Me3 levels is not accompanied by alterations in global levels of the corresponding histone methyltransferase EZH2, the catalytic subunit of the polycomb repressive complex 2 (PRC2). Likewise no alterations in global levels of BMI1, a component of the PRC1 complex, which binds to H3K27Me3-modified histones or the global expression levels of the histone demethylase JMJD3, which removes the methyl marks on H3K27, were observed.
Answer: Together, our data show that in atherosclerosis development alterations in global levels of H3K27Me3 occur. The reduction in the number of nuclei in the tunica media that display the repressive H3K27Me3 mark in vessels with advanced atherosclerosis plaques therefore could be a reflection of the dynamic pattern of smooth muscle cell differentiation and proliferation associated with atherosclerotic disease.
[EX A]: Are global histone H3 lysine 27 triple methylation levels reduced in vessels with advanced atherosclerotic plaques?

[EX Q]: Context: Hepatic artery thrombosis is a rare but extremely troublesome condition after liver transplantation. Recently, urgent arterial revascularization has been used as rescue therapy, leading to improved graft and patient survivals. Hepatic artery ligation produces a progressive reduction in portal vein blood flow. Theoretically, a hyperemic response may be expected following hepatic artery reperfusion (hepatic artery buffer response, HABR). In this study, we tested the hypothesis that HABR can maintain adequate liver oxygenation after temporary liver dearterialization.', 'Seven dogs (19.7 +/- 1.2 kg) subjected to 60 minutes of hepatic artery occlusion were observed for 120 minutes thereafter. Systemic hemodynamics was evaluated through Swan-Ganz and arterial catheters, and splanchnic perfusion by portal vein and hepatic artery blood flows (PVBF and HABF) via an ultrasonic flowprobe. Liver enzymes (ALT and LDH) and systemic and hepatic oxygen delivery (DO2hepat) were calculated using standard formulae.', 'Hepatic artery occlusion induced a progressive reduction in PVBF and DO2hepat. A complete restoration of HABF after hepatic artery declamping was observed; however, the DO2hepat (33.3 +/- 5.9 to 16.5 +/- 5.9 mL/min) did not return to the baseline levels.
Answer: Temporary hepatic artery occlusion induced a progressive decrease in portal vein blood flow during ischemia, an effect that continued during the reperfusion period. The hepatic artery blood flow was promptly restored after declamping. However, HABR was not able to restore hepatic oxygen delivery to baseline levels during the reperfusion period.
[EX A]:
Does hepatic arterial buffer response fail to restore hepatic oxygenation after temporary liver dearterialization in canines?