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.

Q: Context: The tumor necrosis factor (TNF) gene is located within the highly polymorphic major histocompatibility complex region, exhibiting the -308 GA promoter region polymorphism and six microsatellites (TNFa-f) spanning the region nearby the TNF locus.', 'In the present study, we evaluated the frequency of -308 GA and TNFa-e polymorphisms and respective haplotypes (in chromosomal sequence: TNFd-TNFe-308GA-TNFc-TNFa-TNFb), in 222 patients with AIDS, 52 of whom exhibited cytomegalovirus retinitis, and in 202 healthy HIV-negative individuals.', 'TNF microsatellite and single nucleotide polymorphism typings were performed by PCR followed by polyacrylamide gel electrophoresis.', 'The TNF-308A allele and the 4-3-G-2-7-1 haplotype were associated with susceptibility to AIDS, whereas the TNFb4 allele and the 3-3-G-1-11-4 haplotype were associated with protection against AIDS development. The TNFc2 allele and the 4-1-G-2-2-1 haplotype, which contains the TNFc2 allele, were associated with cytomegalovirus retinitis.
Answer: This study highlights that polymorphic sites spanning the region nearby the TNF locus are associated with AIDS per se and with cytomegalovirus retinitis in AIDS patients.

A: Are tumor necrosis factor region polymorphisms associated with AIDS and with cytomegalovirus retinitis?
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Q: Context: DNA methylation at CpG dinucleotides is modified in tumorigenesis with potential impact on transcriptional activity.', 'We used the Illumina 450 K platform to evaluate DNA methylation patterns of 50 metastatic melanoma tumors, with matched gene expression data.', 'We identified three different methylation groups and validated the groups in independent data from The Cancer Genome Atlas. One group displayed hypermethylation of a developmental promoter set, genome-wide demethylation, increased proliferation and activity of the SWI/SNF complex. A second group had a methylation pattern resembling stromal and leukocyte cells, over-expressed an immune signature and had improved survival rates in metastatic tumors (p < 0.05). A third group had intermediate methylation levels and expressed both proliferative and immune signatures. The methylation groups corresponded to some degree with previously identified gene expression phenotypes.
Answer: Melanoma consists of divergent methylation groups that are distinguished by promoter methylation, proliferation and content of immunological cells.

A: Are dNA methylation subgroups in melanoma associated with proliferative and immunological processes?
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Q: Context: Determination of endothelial function has emerged as a crucial factor in the assessment of individual cardiovascular risk. Sonographic measurement of flow-mediated dilation (FMD) is the most widespread technique to assess endothelial function, but analysis is very time-consuming and requires an experienced examiner. Recently, it was speculated that a reduction of small artery compliance (C2) measured by pulse wave analysis might be an indicator of endothelial dysfunction. In the present study, we investigated the correlation of pulse wave analysis parameters and endothelial function with special regard to patients who are at increased risk for endothelial dysfunction.', 'One hundred and thirty-six subjects (65 male, 71 female) were included in the study. One hundred and twenty-three probands were hypertensive. Endothelium-dependent vasodilation was assessed sonographically (flow-mediated dilation) using standard protocols and as a change of reflection index (deltaRI) after application of salbutamol by photoplethysmography. Small artery compliance, large artery compliance (C1), and systemic vascular resistance (SVR) were measured by computerized pulse wave analysis of the radial artery (CR-2000; Hypertension Diagnostics, Eagan, Minnesota, USA) and were tested for correlation with FMD.', 'Mean FMD was 6.29 +/- 2.86%. Means of pulse wave analysis-derived vascular parameters were 4.91 +/- 2.86 ml/mmHg x 100 (C2), 13.35 +/- 5.41 ml/mmHg x 10 (C1) and 1611.6 +/- 348.5 dynes x s x cm(-5) (SVR). Regression analysis excluded a significant correlation between FMD, C2, C1 and SVR (r2 < 0.05 each) both in hypertensives and normotensives. There was no significant correlation between C2 and deltaRI (r2 = 0.023).
Answer: Our findings show that static measurement of vascular parameters by an automated pulse-wave analysis procedure cannot be used to assess endothelial function. Further studies are needed to examine whether a dynamic measurement of arterial compliance before and after stimulation of the endothelium (e.g. by ischemia) might quantify endothelial dilatory capacity in a better way.

A:
Is small artery elasticity assessed by pulse wave analysis no measure of endothelial dysfunction?
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