TASK DEFINITION: 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.
PROBLEM: Context: Elevated myeloperoxidase (MPO) levels are predictive of high cardiovascular (CV) risk in the general population. The value of MPO as a CV marker in the HIV population has not been investigated.', 'Medical records were reviewed to identify HIV+ patients with a documented CV event (myocardial ischemia/infarction) and stored plasma samples within 12 months prior to the event. HIV+ adults with no CV history and with similarly available stored plasma samples were site-, age-, and gender-matched 1:1 to cases.', 'We identified 124 participants (62 case-control pairs): 94% male, median age 46 years. Median (IQR) MPO levels (pmoles/L) were lower in cases vs. controls: 292 (235-376) vs. 320 (249-467); p= .004. Cases were more likely to have other CV risk factors, including smoking, hypertension, and higher cholesterol and triglycerides. The observed MPO directional difference persisted after controlling for CV risk factors. In the reduced model, observed differences in MPO remained independently and negatively associated with CV event (p= .03) after adjusting for two positively associated risk factors, differences in cholesterol levels (p= .01), and differences in smoking history (ever smoked vs. never smoked; p= .04). Differences in triglyceride levels and hypertension were not statistically significant independent risk factors in this sample (p> .05). Within cases, MPO was negatively correlated with CD4 count (rs= -0. 40, p= .0023) and age (rs= -0. 34, p= .01). In contrast, age at blood draw was positively correlated with MPO in controls (rs= 0.28, p= .031) and CD4 was uncorrelated (rs= -0. 01, p> .9). No other factors were significantly correlated with MPO within groups.\Question: Are higher plasma myeloperoxidase levels associated with an increased risk for cardiovascular events in HIV-infected adults?

SOLUTION: In contrast to the general population, higher MPO levels were not predictive of CV events in this study, underscoring the fact that pathways operative in HIV arteriopathy may be distinct from traditional CV disease pathogenesis.

PROBLEM: Context: To systematically review methodological articles which focus on nonpublication of studies and to describe methods of detecting and/or quantifying and/or adjusting for dissemination in meta-analyses. To evaluate whether the methods have been applied to an empirical data set for which one can be reasonably confident that all studies conducted have been included.', 'We systematically searched Medline, the Cochrane Library, and Web of Science, for methodological articles that describe at least one method of detecting and/or quantifying and/or adjusting for dissemination bias in meta-analyses.', 'The literature search retrieved 2,224 records, of which we finally included 150 full-text articles. A great variety of methods to detect, quantify, or adjust for dissemination bias were described. Methods included graphical methods mainly based on funnel plot approaches, statistical methods, such as regression tests, selection models, sensitivity analyses, and a great number of more recent statistical approaches. Only few methods have been validated in empirical evaluations using unpublished studies obtained from regulators (Food and Drug Administration, European Medicines Agency).\Question: Are methods for detecting , quantifying , and adjusting for dissemination bias in meta-analysis described?

SOLUTION: We present an overview of existing methods to detect, quantify, or adjust for dissemination bias. It remains difficult to advise which method should be used as they are all limited and their validity has rarely been assessed. Therefore, a thorough literature search remains crucial in systematic reviews, and further steps to increase the availability of all research results need to be taken.

PROBLEM: Context: The development of transplant coronary artery disease is associated with neovascularization in the thickened neointima. We previously reported that captopril inhibits neointimal proliferation in a rat allograft model. We postulated that angiogenic inducers are upregulated post-transplantation and captopril ameliorates transplant coronary artery disease by suppressing the angiogenic activity of coronaries.', 'Animals received no treatment or captopril (50 mg/kg/day). Allograft hearts were analyzed at post-transplantation Days 0, 14, and 21 and angiogenic inducer, plasma platelet-activating factor, determined. The conditioned media from coronaries and myocardium were tested for vascular endothelial growth factor, thrombospondin-1 and angiogenic activity using an endothelial migration assay and rat corneal neovascularization assay.', 'The captopril-treated group had reduced plasma platelet-activating factor and coronary media revealed earlier upregulation of thrombospondin-1 secretion, diminished vascular endothelial growth factor and no angiogenic activity. At Day 0, the coronary and myocardial conditioned medium had inhibitory activity due to thrombospondin-1, and circulating levels of platelet-activating factor were negligible. By 21 days post-transplantation, plasma platelet-activating factor was elevated and the conditioned medium from untreated coronaries had significantly higher angiogenic activity due to increased vascular endothelial growth factor whereas the myocardium remained non-angiogenic.\Question: Does captopril suppress post-transplantation angiogenic activity in rat allograft coronary vessels?

SOLUTION:
After transplantation, coronary vessels switch to an angiogenic phenotype and vascular endothelial growth factor contributes to the high angiogenic activity, possibly exacerbated by high circulating levels of platelet-activating factor. The ability of captopril to modulate angiogenic mediators and maintain the allograft coronary to its normal anti-angiogenic phenotype may be one mechanism by which it suppresses transplant coronary artery disease.