165 research outputs found
Histological characterization of CT-identified osteoarthritic subchondral cysts and co-registration of CT with MRI
No full textOsteoarthritis (OA) is a chronic disease that affects the joints, most commonly hands, hips, knees, feet, and spine (Litwic et al. 2013). The disease becomes more common with advanced age and is one of the most prevalent causes of disability in older populations. Currently there is no cure besides total joint replacement surgery, and there will be approximately 4 million Americans living with a hip replacement by the end of the next decade (Maradit Kremers et al. 2015).
Osteoarthritis was classically characterized as a disease of progressive articular cartilage degradation, but the degeneration involves all tissues of the synovial joint including the periarticular muscles, joint capsule, synovium, ligaments, and subchondral and metaphyseal bone. The cause of pain in OA is not well understood, but it is known that bone marrow lesions (BMLs) identified in subchondral bone by MRI are an important determinant of pain (Felson et al. 2001; Kumar et al. 2013). Abnormal blood vessel growth may be responsible MRI signature of BMLs, and the commonality between pathways for angiogenesis and neurogenesis suggests this pathologic process may be the source of pain in OA. The objective of this study was to characterize the histologic nature of subchondral cysts identified by micro computed tomography (μCT) which had been registered with MRI images in which marrow lesions were identified.
Femoral heads were collected from 10 patients (6 females and 4 females; age 29-80) who underwent total hip arthroplasty. All patients had MRIs performed within 6 months prior to surgery. The heads were fixed and scanned with μCT to identify cysts in the subchondral bone. A block of the femoral head containing the cyst of interest was resected and processed for histologic analysis. The sections were stained with either Safranin-O and Fast Green or hematoxylin and eosin to view the nature and composition of the tissue. A two-dimensional image from the μCT that corresponded to the histologic slice was matched with a coronal view from the MRI. The primary compressive group was reliably identified on μCT images and served as good indicator for orienting the CT to match with the MRI. The subchondral cysts that were matched to MRI all consisted of predominantly fibrous bone marrow and frequently had a large number of blood vessels within the tissue. Three of the eight cysts had cartilage intrusions that were located mostly within peripheral trabecular bone, though one cyst contained a nodule of cartilage surrounded by organized fibers with the texture of granulation tissue. The process of image registration was mostly performed manually, but the development of this process will contribute to a more refined, semi-automated process in the future. The ability to correlate the histopathology of CT-identified lesions with a signature patter on MRI will be an important tool for better characterizing the nature of BMLs and understanding the pathogenesis of OA
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Catheter ablation of ventricular tachycardia in patients with post-infarction cardiomyopathy
No full textMonomorphic ventricular tachycardia (VT) in patients with post-infarction cardiomyopathy (CMP) is caused by reentry through slowly conducting tissue with in areas of myocardial scar. The use of implantable cardioverter-defibrillators (ICDs) has helped to
Social policies and socioeconomic indicators for transitional economies
No full textIncludes bibliographySerie de artículosAs part of the United Nations Development Programs thematic focus on poverty eradication and Poverty Strategy Initiatives, the UNDP, in cooperation with the Armenian Government, the World Bank and the Economic Commission for Latin America and the Caribbean (ECLAC), organized a workshop on Social Indicators to be held at Yrevan, Armenia on November 13-14, 1997. In accordance with the United Nations Global Conferences and their goals, the workshop pursued as its goal the elaboration of poverty initiatives to alleviate poverty, preserve the human capital and adjust it to new market conditions, which could be attained by providing detailed and targeted information, improving the survey methodologies, determining the choice of main social indicators to be used with the consideration of the national specifics. This publication presents ECLACs conribution to the workshop. Rolando Franco gives an overview of some economic, political and social characteristics, which are at the core of a transition from planned to market economies. He refers to differences and similarities between the change of the economic model observed in Latin America and the model taking shape in transitional economies, giving charactersitic features of the import-substitution model and the post-adjustment model. Afterwards, the author concentrates in presenting two paradigms within the context of the Latin American social policy characteristics, which correspond to the two development models that have been applied in the region, before and after what has been called the crisis of the 1980s". On the other side, Pascual Gerstenfeld marks that indicators should help to identify the main causes and effects of social trends and provide useful information for the design of social policies. Further he analyses a set of indicators based on data from household surveys, which have contributed in a large measure to the Latin American experience in quantitative socioeconomic analysis. Following the above, he presents reflections on social indicators for the analysis of the well-being and equity in societies in transition. Finally, Ernesto Cohen covers the social policy evaluation through assessing social projects, in a way that they allow a resign of and reallocation of resources and provide a strategic avenue for rationalizing the government social expenditure. He goes through the project cycle, the advantages of the cost-impact analysis, and the importance of monitoring efficiency of social programs.
Ventricular tachycardia recurrence after “failed” endocardial ablation: A Sisyphean challenge?
No full textFunctional Block in the Posterior Left Atrium Another Piece in the Puzzle of Atrial Fibrillation Initiation⁎⁎Editorials published in the Journal of the American College of Cardiology reflect the views of the authors and do not necessarily represent the views of JACC or the American College of Cardiology.
No full textHigh power radiofrequency ablation for atrial fibrillation – establishing a standardized protocol
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Mapping of Complex Atrial Tachycardia Circuits by 3-Dimensional Body Surface Mapping The First Step in the Dawn of a New Era∗
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