Characterization of Spontaneous Bone Marrow Recovery after Sublethal Total Body Irradiation: Importance of the Osteoblastic/Adipocytic Balance

Many studies have already examined the hematopoietic recovery after irradiation but paid with very little attention to the bone marrow microenvironment. Nonetheless previous studies in a murine model of reversible radio-induced bone marrow aplasia have shown a significant increase in alkaline phosphatase activity (ALP) prior to hematopoietic regeneration. This increase in ALP activity was not due to cell proliferation but could be attributed to modifications of the properties of mesenchymal stem cells (MSC). We thus undertook a study to assess the kinetics of the evolution of MSC correlated to their hematopoietic supportive capacities in mice treated with sub lethal total body irradiation. In our study, colony-forming units – fibroblasts (CFU-Fs) assay showed a significant MSC rate increase in irradiated bone marrows. CFU-Fs colonies still possessed differentiation capacities of MSC but colonies from mice sacrificed 3 days after irradiation displayed high rates of ALP activity and a transient increase in osteoblastic markers expression while pparγ and neuropilin-1 decreased. Hematopoietic supportive capacities of CFU-Fs were also modified: as compared to controls, irradiated CFU-Fs significantly increased the proliferation rate of hematopoietic precursors and accelerated the differentiation toward the granulocytic lineage. Our data provide the first evidence of the key role exerted by the balance between osteoblasts and adipocytes in spontaneous bone marrow regeneration. First, (pre)osteoblast differentiation from MSC stimulated hematopoietic precursor's proliferation and granulopoietic regeneration. Then, in a second time (pre)osteoblasts progressively disappeared in favour of adipocytic cells which down regulated the proliferation and granulocytic differentiation and then contributed to a return to pre-irradiation conditions

Belgium General Election Study 1999

Following the first two Belgian National Election Studies, which were held after the General Election of 24 November 1991 and 21 May 1995, a third, similar study was set up in connection with the General Election of 13 June 1999. The Study was supported financially by the Federal Services for Technical, Cultural and Scientific Affairs, under the National Ministry of Science. Similar to the first two General Election Studies, this third study focuses on general political attitudes and behavior. Data has been collected on political information and knowledge, perceptions of political bodies such as parties, and perceptions of problems and important issues. Other questions deal with party identification, party preferences, feelings of political efficacy, and the nature and extent of political participation. Perceptions of social class and (economic) well-being, authoritarian attitudes, attitudes to immigrant workers, political corruption and the environment are some of the other areas investigated in this study. Extensive demographic data on the respondents and their families have also been collected

Belgium, General Election Study 1991

Systematic analysis of change in political opinions and behaviour of the Belgium electorate. Individualism / feelings of loneliness and emptiness, social contacts / social leadership / placement of political parties on left-right scale / reasons for ( not ) casting vote for party in last elections for Chamber of Representatives / list or name vote / voted for same party for Senate and Chamber/ reasons for different party choice / 4 most important issues in party choice / called upon services of politicians in the last 4 years/ party of involved politician / did respondent vote for this particular politician / membership of health insurance organization / active membership of ( religious, political ) organizations / respondent considers himself as a follower of one or more parties / ranking of parties on best-worse dimension / political participation and action / viewpoints of respondent himself and of parties on environment, immigrants, free enterprise, privacy, economic growth, public order, Flanders-Wallonia, autonomy of Brussels / materialism-postmaterialism / economic and cultural conservatism / emancipation of women / authoritarianism / influence on politics / ethnocentrism / party membership of well-known politicians / cultural community identification/ Flemish-Walloons culture / environmental involvement / influence of election campaign on vote / language of questionnaire / date of interview / atmosphere of interview. Background variables: basic characteristics/ residence/ household characteristics/ occupation/employment/ income/capital assets/ education/ social class/ politics/ religion/ consumption of durables/ organizational membershi