Comparison of gamma- and UV-light-induced EPR spectra of enamel from deciduous molar teeth.

From previous work, it is known that CO2- radicals in tooth enamel are induced by gamma as well as by UV-light exposure. The parameters of the EPR signal of the CO2- radical were found to be independent of the source of exposure. However, it would be desirable for retrospective dosimetry to identify other characteristic features of the EPR spectrum of tooth enamel, which would allow differentiation between the two sources of exposure. In the present work, enamel of deciduous molars was exposed to gamma-radiation from a 60Co-source and 254 nm UV-light from a low-pressure mercury lamp. The resulting EPR spectra were deconvoluted, and the native spectrum simulated from spectra of the CO2- radical, and two further EPR lines. Both EPR signals of the native spectrum were located at g=2.0046, but were different in line shape and width. One was a 1 mT wide isotropic signal of Gaussian line shape while the other was a 0.7 mT wide axial signal of Lorentzian line shape. A comparable study of the amplitudes of the native and CO2- signals was done before and after gamma- and UV-light exposure. While the native signals were found to be only slightly sensitive to gamma-radiation, their amplitude increased significantly on UV-light exposure. Feasibilities are discussed to distinguish different radiation sources by exposure-induced alterations of the native EPR spectrum.     

In-vivo generation of leukaemia-derived dendritic cells

Adoptive immunotherapy with transfusion of donor lymphocytes in allogeneic stem cell chimeras has been successful in the treatment of recurrent chronic myelogenous leukaemia (CML) and some patients with acute myeloid leukaemia (AML). The hypothesis that the graft-vs-leukaemia effect (GVL) is promoted by leukaemia-derived dendritic cells has been supported by the concurrent treatment of patients with cytokines that are known to induce differentiation of leukaemia cells towards dendritic cells. In combination with donor lymphocyte transfusions, treatment with interferon-alpha and granulocyte-macrophage colony-stimulating factor has been studied in patients with recurrent CML and AML, and pre-emptively in patients with high-risk AML. Long-term remissions have been observed in cytokine-treated patients, indicating the beneficial effect of cytokine stimulation of GVL reactions. This is likely to be due to differentiation of leukaemia progenitor cells towards dendritic cells in vivo.     

The GSF family of voxel phantoms

Voxel phantoms are human models based on computed tomographic or magnetic resonance images obtained from high-resolution scans of a single individual. They consist of a huge number of volume elements (voxels) and are at the moment the most precise representation of the human anatomy. The purpose of this paper is to introduce the GSF voxel phantoms, with emphasis on the new ones and highlight their characteristics and limitations. The GSF voxel family includes at the moment two paediatric and five adult phantoms of both sexes, different ages and stature and several others are under construction. Two phantoms made of physical calibration phantoms are also available to be used for validation purposes. The GSF voxel phantoms tend to cover persons of individual anatomy and were developed to be used for numerical dosimetry of radiation transport but other applications are also possible. Examples of applications in patient dosimetry in diagnostic radiology and in nuclear medicine as well as for whole-body irradiations from idealized external exposures are given and discussed.     

Persistent Pollutants in Sediments of the Yangtse River

Received: 25 June 1999/Accepted: 23 November 1999     

Determinants of health policy impact: a theoretical framework for policy analysis

Summary This paper addresses the role of policy and evidence in health promotion. The concept of von Wrights logic of events is introduced and applied to health policy impact analysis.According to von Wright (1976), human action can be explained by a restricted number of determinants: wants, abilities, duties, and opportunities. The dynamics of action result from changes in opportunities (logic of events). Applied to the policymaking process, the present model explains personal wants as subordinated to political goals. Abilities of individual policy makers are part of organisational resources. Also, personal duties are subordinated to institutional obligations. Opportunities are mainly related to political context and public support. The present analysis suggests that policy determinants such as concrete goals, sufficient resources and public support may be crucial for achieving an intended behaviour change on the population level, while other policy determinants, e.g., personal commitment and organisational capacities, may especially relate to the policy implementation process. The paper concludes by indicating ways in which future research using this theoretical framework might contribute to health promotion practice for improved health outcomes across populations.     

Therapeutic vaccination with MVA-HIV-1 nef elicits Nef-specific T-helper cell responses in chronically HIV-1 infected individuals

Vaccination is currently considered as an additional therapeutic approach to stimulate HIV-specific immune response in subjects that could not naturally control HIV. Ten chronically HIV infected individuals have been vaccinated with a modified vaccinia Ankara (MVA)-HIV-1(LAI)-nef vector in order to assess safety and immunogenicity. No significant adverse effects were observed during the course of vaccination indicating for the first time that the highly attenuated vaccinia-virus vector MVA is safe in HIV-1 infected individuals. We observed a CD4 T-cell response to Nef in the majority of vaccinated chronically HIV infected individuals. In two subjects CD4 T-cell response was directed to previously unidentified Nef epitopes. The strong Nef-specific CD4 T-cell response elicited by MVA-nef vaccination provides a rationale for immunotherapeutic interventions in HIV infected individuals with suppressed CD4 T-cell responses. Moreover, the CD4 T-cell response elicited was comparable with that usually detected in long-term non-progressor (LTNP) suggesting an improvement in the immunological status of the vaccinated subjects. Furthermore, the new putative CD4 epitopes described here hold promise as important tools for epitope-based vaccination.