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.

Q: 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?

A: 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.
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Q: Context: Cord blood (CB) hematopoietic stem cell transplantation has often been limited by the scarcity of stem cells. Therefore, the number of CB hematopoietic stem/progenitor cells (HSPCs) should be increased while maintaining the stem cell characteristics.', 'We designed an ex vivo culture system using endothelial progenitor cells (EPCs) as stroma to determine the capacity of expanding CB-HSPCs in a defined medium, the effect on engraftment of the expanded cells in a mouse model and the underlying mechanism.', "After 7 days of culture, compared with those cultured with cytokines alone (3.25 0.59), CD34+ cells under contact and non-contact co-culture with EPCs were expanded by 5.38 0.61 (P = 0.003) and 4.06 0.43 (P = 0.025)-fold, respectively. Direct cell-to-cell contact co-culture with EPCs resulted in more primitive CD34+ CD38- cells than stroma-free culture (156.17 21.32 versus 79.12 19.77-fold; P = 0.010). Comparable engraftment of day 7 co-cultured HSPCs with respect to HSPCs at day 0 in nonobese diabetic-severe combined immunodeficiency disease (NOD/SCID) mice was measured as a percentage of chimerism (13.3% 11.0% versus 16.0% 14.3%; P = 0.750). EPCs highly expressed interleukin 6 (IL6) and angiopoietin 1 (ANGPT1), the hematopoietic- related cytokines. A higher transcriptional level of WNT5A genes in EPCs and co-cultured HSPCs suggests that the activation of Wnt signaling pathway may play a role in HSPCs' expansion ex vivo.\Question: Do endothelial progenitor cells promote efficient ex vivo expansion of cord blood-derived hematopoietic stem/progenitor cells?

A: These data demonstrated that EPCs improve the CD34+ population but do not compromise the repopulating efficacy of the amplified HSPCs, possibly via cytokine secretion and Wnt signaling pathway activation.
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Q: Context: Coronary artery calcium (CAC) is a powerful CAD risk marker when assessed by dedicated calcium scoring CT scan. We assessed diagnostic implications of CAC visible on attenuation correction CT scans (CTAC) from SPECT/CT myocardial perfusion imaging (MPI).', 'Visual presence or absence of CAC was assessed on CTAC in 1047 consecutive patients undergoing SPECT/CT MPI. Accuracy of MPI was assessed in patients undergoing invasive coronary angiography (ICA) within 1year (n=109). Outcomes were identified by retrospective chart review.', 'Prevalence of true positive SPECT/CT MPI studies was greater among patients with CAC on CTAC (70% vs 16%; p<.001); prevalence of false positive studies was greater among those without (68% vs 15%; p<.001). PPV of MPI was 0.82 in patients with CAC, but only 0.19 in those without. Within median follow-up of 27.7months, patients with CAC had higher all-cause mortality (6% vs 0.4%; p<.001), more late revascularizations (8% vs 0.4%; p<.001), and more MI (5% vs 0.2%; p<.001). Hazard ratio for all-cause mortality, MI, or late revascularization was 22.7 (p<.001) for patients with CAC vs those without.\Question: Does visual identification of coronary calcifications on attenuation correction CT improve diagnostic accuracy of SPECT/CT myocardial perfusion imaging?

A:
Visual assessment of CAC on CTAC should be performed during SPECT/CT MPI because it affects diagnostic certainty and may improve risk stratification.
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