|Author||Rajasree, S. ♦ Umashankar, P. R. ♦ Lal, A. V. ♦ Sarma, P. S. ♦ Kartha, C. C.|
|Source||Sree Chitra Tirunal Institute for Medical Sciences & Technology|
|Subject Domain (in DDC)||Technology ♦ Medicine & health ♦ Human physiology|
|Subject Domain (in MeSH)||Cell Physiological Phenomena ♦ Physiological Phenomena ♦ Musculoskeletal and Neural Physiological Phenomena ♦ Biological Sciences|
|Abstract||Several studies have demonstrated that excess of vitamin D-3 is toxic particularly to vascular tissues. A notable pathological feature is arterial calcification. The nature of the toxic metabolite in hypervitaminosis D and the pathogenesis of arterial calcification are not clearly understood. The present study was undertaken to explore whether arterial calcification is a sequel of increased calcium uptake by arterial smooth muscle mediated by up regulation of vitamin D receptor in the cells in response to elevated circulating levels of vitamin D-3 in serum. The experimental study was performed in 20 New Zealand white female rabbits aged 6 months. Animals in the test group were injected 10,000 IU of cholecalciferol intramuscularly twice a week for one month. Six control animals were given intra-muscular injections of plain cottonseed oil. Animals were sacrificed and aortas were examined for pathological lesions, 1,25-dihyroxyvitamin D-3 (1,25(OH)(2) D-3) receptor levels and Ca-45 uptake in smooth muscle cells. Serum samples collected at intervals were assayed for levels of 25-OH-D-3 and calcium. The results showed that in animals given injections of cholecalciferol, serum levels of 25-OH-D-3 Were elevated. In four of these animals calcification and aneurysmal changes were seen in the aorta. Histological lesions comprised of fragmentation of elastic fibers as well as extensive loss of elastic layers. 1,25(OH)(2) D-3 receptor levels were up regulated and Ca-45 uptake enhanced in aortas of animals which were given excessive vitamin D-3. The evidences gathered suggest that excess vitamin D is arteriotoxic and that the vitamin induces arterial calcification through up regulation of 1,25(OH)(2)D-3 receptor and increased calcium uptake in smooth muscle cells of the arteries. (C) 2002 Elsevier Science Inc. All rights reserved.|
|Education Level||UG and PG|
|Learning Resource Type||Article|
|Educational Framework||Medical Council of India (MCI)|
Ministry of Human Resource Development (MHRD) under its National Mission on Education through Information and Communication Technology (NMEICT) has initiated the National Digital Library of India (NDLI) project to develop a framework of virtual repository of learning resources with a single-window search facility. Filtered and federated searching is employed to facilitate focused searching so that learners can find out the right resource with least effort and in minimum time. NDLI is designed to hold content of any language and provides interface support for leading vernacular languages, (currently Hindi, Bengali and several other languages are available). It is designed to provide support for all academic levels including researchers and life-long learners, all disciplines, all popular forms of access devices and differently-abled learners. It is being developed to help students to prepare for entrance and competitive examinations, to enable people to learn and prepare from best practices from all over the world and to facilitate researchers to perform inter-linked exploration from multiple sources. It is being developed at Indian Institute of Technology Kharagpur.
NDLI is a conglomeration of freely available or institutionally contributed or donated or publisher managed contents. Almost all these contents are hosted and accessed from respective sources. The responsibility for authenticity, relevance, completeness, accuracy, reliability and suitability of these contents rests with the respective organization and NDLI has no responsibility or liability for these. Every effort is made to keep the NDLI portal up and running smoothly unless there are some unavoidable technical issues.
Ministry of Human Resource Development (MHRD), through its National Mission on Education through Information and Communication Technology (NMEICT), has sponsored and funded the National Digital Library of India (NDLI) project.
For any issue or feedback, please write to email@example.com