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: Guanidinoacetic acid (GAA) is an experimental dietary additive that might act as a creatine source in tissues with high-energy requirements. In this case study, we evaluated brain levels of creatine in white matter, gray matter, cerebellum, and thalamus during 8\xa0wk oral GAA administration in five healthy men and monitored the prevalence and severity of side effects of the intervention.', 'Volunteers were supplemented daily with 36\xa0mg/kg body weight (BW) of GAA for the first 4\xa0wk of the intervention; afterward GAA dosage was titrated ≤60\xa0mg/kg BW of GAA daily. At baseline, 4, and 8\xa0wk, the participants underwent brain magnetic resonance spectroscopy, clinical chemistry studies, and open-ended questionnaire for side-effect prevalence and severity.', 'Brain creatine levels increased in similar fashion in cerebellum, and white and gray matter after GAA supplementation, with an initial increase of 10.7% reported after 4\xa0wk, and additional upsurge (7.7%) from the weeks 4 to 8 follow-up (P\xa0<\xa00.05). Thalamus creatine levels decreased after 4\xa0wk for 6.5% (P\xa0=\xa00.02), and increased nonsignificantly after 8\xa0wk for 8% (P\xa0=\xa00.09). GAA induced an increase in N-acetylaspartate levels at 8-wk follow-up in all brain areas evaluated (P\xa0<\xa00.05). No participants reported any neurologic adverse event (e.g., seizures, tingling, convulsions) during the intervention.
Answer: Supplemental GAA led to a region-dependent increase of the creatine pool in the human brain. This might be relevant for restoring cellular bioenergetics in disorders characterized by low brain creatine and functional enzymatic machinery for creatine synthesis, including neurodegenerative diseases, brain tumors, or cerebrovascular disease.

A: Does dietary guanidinoacetic acid increase brain creatine levels in healthy men?
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Q: Context: Tissue factor (TF) contributes to thrombosis following plaque disruption in acute coronary syndromes (ACS). Aim of the study was to investigate the impact of plasma TF activity on prognosis in patients with ACS.', 'One-hundred seventy-four patients with unstable Angina pectoris (uAP) and 112 patients with acute myocardial infarction (AMI) were included with a mean follow up time of 3.26 years. On admission, plasma TF activity was assessed. Patients were categorized into 2 groups: a high-TF activity group with TF >24 pmol/L and low TF activity group with TF ≤ 24 pmol/L. Fifteen cardiovascular deaths occurred in the uAP group and 16 in the AMI group. In AMI TF activity was 24,9 ± 2,78 pmol/l (mean ± SEM) in survivors and 40,9 ± 7,96 pmol/l in nonsurvivors (P = 0.024). In uAP no differences were observed (25.0 ± 8.04 pmol/L nonsurvivors vs. 25.7 ± 2.14 pmol/L survivors; P = 0.586). Kaplan-Meier estimates of survival at 3.26 years regarding TF activity in AMI were 81.3% and 92.2% with an hazard ratio of 3.02 (95% CI [1.05-8.79], P = 0.03). The Cox proportional hazards model adjusting for correlates of age and risk factors showed that plasma TF activity was an independent correlate of survival (hazard ratio 9.27, 95% CI [1.24-69.12], P = 0.03). In an additional group of patients with uAP and AMI, we identified circulating microparticles as the prevailing reservoir of plasma TF activity in acute coronary syndromes.
Answer: Systemic TF activity in AMI has an unfavorable prognostic value and as a marker for dysregulated coagulation may add to predict the atherothrombotic risk.

A: Does plasma TF activity predict cardiovascular mortality in patients with acute myocardial infarction?
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Q: Context: We evaluated assays for the measurement of acute phase protein levels in plasma for their usefulness to identify sensitively an inflammatory response to active cytomegalovirus CMV infection in HIV-infected patients.', 'Plasma samples were collected from 28 CMV-seropositive patients with advanced HIV-infection (CD4-cell count <200/microl) before commencement of antiretroviral therapy. Sensitivity, specificity, and area under receiver operating characteristic curve for the selected acute phase protein assays (haptoglobin, fibronectin, high-sensitivity C-reactive protein (hs-CRP), human interleukin-6, serum amyloid A (SAA), and human lipopolysacharide binding protein) were compared with results of a CMV-specific PCR assay.', "CMV viremia was detectable in 8/28 patients. Levels of SAA correlated well with those of hs-CRP (r' = 0.439, P = 0.019 (Spearman rank correlation)). Levels of SAA >3 mg/L discriminated with 100% sensitivity and 40% specificity between HIV-infected patients with and without active CMV infection. Sensitivity of fibronectin was 100% and specificity 15% at a threshold-value corresponding with the lower limit of normal values as defined by the manufacturer of the assay (>29 mg/dL). Levels of the other acute phase proteins evaluated did not correlate with detection of CMV-DNA in plasma.
Answer: Increased levels of SAA indicate sensitively an inflammatory response to active CMV infection. Use of a CMV-specific virological assay is required to confirm the specificity of a high SAA-level but may be limited to samples with high SAA-levels. Hence, screening for increased levels of SAA in patients with advanced HIV-infection may allow early identification of active CMV infection.

A:
Is aymptomatic CMV viremia associated with increased levels of serum amyloid A in patients with advanced HIV-infection?
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