Maastricht University

About: Maastricht University is a education organization based out in Maastricht, Limburg, Netherlands. It is known for research contribution in the topics: Population & Health care. The organization has 19263 authors who have published 53291 publications receiving 2266866 citations. The organization is also known as: Universiteit Maastricht & UM.

Unpacking Black Boxes: Mechanisms and Theory Building in Evaluation:

Abstract: There is growing interest in the concept of ‘‘mechanism’’ across many areas of the social sciences. In the field of program and policy evaluation, a number of scholars have also emphasized the importance of causal mechanisms for explaining how and why programs work. However, there appears to be some ambiguity about the meaning and uses of mechanism-based thinking in both the social science and evaluation literature. In this article we attempt to clarify what is meant by mechanisms in the context of program evaluation by identifying three main characteristics of mechanisms and outlining a possible typology of mechanisms. A number of theoretical and practical implications for evaluators are also discussed, along with some precautions to consider when investigating mechanisms that might plausibly account for program outcomes.

Differential Expression of Bone Matrix Regulatory Proteins in Human Atherosclerotic Plaques

Abstract: In the present study, we examined the expression of regulators of bone formation and osteoclastogenesis in human atherosclerosis because accumulating evidence suggests that atherosclerotic calcification shares features with bone calcification. The most striking finding of this study was the constitutive immunoreactivity of matrix Gla protein, osteocalcin, and bone sialoprotein in nondiseased aortas and the absence of bone morphogenetic protein (BMP)-2, BMP-4, osteopontin, and osteonectin in nondiseased aortas and early atherosclerotic lesions. When atherosclerotic plaques demonstrated calcification or bone formation, BMP-2, BMP-4, osteopontin, and osteonectin were upregulated. Interestingly, this upregulation was associated with a sustained immunoreactivity of matrix Gla protein, osteocalcin, and bone sialoprotein. The 2 modulators of osteoclastogenesis (osteoprotegerin [OPG] and its ligand, OPGL) were present in the nondiseased vessel wall and in early atherosclerotic lesions. In advanced calcified lesions, OPG was present in bone structures, whereas OPGL was only present in the extracellular matrix surrounding calcium deposits. The observed expression patterns suggest a tight regulation of the expression of bone matrix regulatory proteins during human atherogenesis. The expression pattern of both OPG and OPGL during atherogenesis might suggest a regulatory role of these proteins not only in osteoclastogenesis but also in atherosclerotic calcification.