Dynamic Interaction of TTDA with TFIIH Is Stabilized by Nucleotide Excision Repair in Living Cells

Transcription/repair factor IIH (TFIIH) is essential for RNA polymerase II transcription and nucleotide excision repair (NER). This multi-subunit complex consists of ten polypeptides, including the recently identified small 8-kDa trichothiodystrophy group A (TTDA)/ hTFB5 protein. Patients belonging to the rare neurodevelopmental repair syndrome TTD-A carry inactivating mutations in the TTDA/hTFB5 gene. One of these mutations completely inactivates the protein, whereas other TFIIH genes only tolerate point mutations that do not compromise the essential role in transcription. Nevertheless, the severe NER-deficiency in TTD-A suggests that the TTDA protein is critical for repair. Using a fluorescently tagged and biologically active version of TTDA, we have investigated the involvement of TTDA in repair and transcription in living cells. Under non-challenging conditions, TTDA is present in two distinct kinetic pools: one bound to TFIIH, and a free fraction that shuttles between the cytoplasm and nucleus. After induction of NER-specific DNA lesions, the equilibrium between these two pools dramatically shifts towards a more stable association of TTDA to TFIIH. Modulating transcriptional activity in cells did not induce a similar shift in this equilibrium. Surprisingly, DNA conformations that only provoke an abortive-type of NER reaction do not result into a more stable incorporation of TTDA into TFIIH. These findings identify TTDA as the first TFIIH subunit with a primarily NER-dedicated role in vivo and indicate that its interaction with TFIIH reflects productive NER

KWALITATIEVE CHRONISCHE ZORG IN VLAANDEREN: BELEMMERENDE EN BEVORDERENDE FACTOREN PERCEPTIES EN MENINGEN VAN ZORGVERLENERS IN DE EERSTE LIJN

Background: The highly increased prevalence of chronic conditions challenges the actual health care systems. The Flemish governments has adopted the Chronic Care Model as the mainframe for health policy changes. However until now, there was no major practice change in the way how health care is provided in primary care. Most providers continue to work in the classic way on their own with few multidisciplinary contacts, presence of silos between primary and secondary care, lack of planned population management, little use of existing guidelines... Therefore, the Flemish government ordered Domus Medica, the Flemish General Practice professional organisation, to develop an action research project. The aim of the project was 1. To promote and spread the chronic care model amongst Flemish health care workers; 2. To evaluate both barriers and facilitators towards its implementation. Method: Domus Medica organised a large survey in 16 Flemish regions. Therefore it put up 1 national and 16 regional steering committees. Each regional steering had to involve as many health care workers in the process as possible. Each committee was free to use its own methods. In total, six different methods were used: electronic survey, survey on paper, face to face interviews, workshops, seminars and ‘world cafes’. Most regions used a ‘mixed method’ approach. Each region had to write down the results into a report. The collected reports were analysed. Barriers and facilitators were listed for each region and then brought together. This ‘long’ list was analysed by an expert who used the ‘Implementation model’ (Grol, Wensing) to filter the most relevant items. These results were fed back for validation towards the involved stakeholders: respondents had to mark their agreement on a Likert scale from 1 (strongly disagree) to 4 (strongly agree). Only those items that obtained a score of 3 or 4 by more than 70% of all respondents were selected. This lead to a ‘short list’ summed up according to the pillars of the Chronic Care Model. Finally the results were thoroughly discussed leading to a report with recommendations. Results: 598 people responded to the written surveys and interviews and 943 people participated to the workshops, seminars and world cafes. There was some overlap but in total, more than 1300 different persons participated including about 400 General Practitioners and nurses and 200 physiotherapists and pharmacists. 166 people participated in the validation process. The ‘long list’ contained 349 barriers and 167 facilitators and the short ‘short list’ 63 barriers and 39 facilitators. The report for the Flemish Minister of health contained 17 core recommendations. Main barriers remain the concept of patient empowerment and health promotion, multidisciplinary teamwork, integration and continuity between hospital and primary care and between health care and social welfare. Evidence Based Medicine is inadequately acquired, especially by non-physicians. ICT is experienced as thé necessary tool for integration and communication. However in practice it is a source of major concern because systems are often unstable, necessary knowledge to use the systems and to resolve technical problems are lacking and ICT investment is both expensive and time consuming. Two major structural barriers that hamper all evolution towards integrated chronic care were put forward: the payment system that enables a comfortable revenue by fee for service and unfitted organisational structures in primary care, both at micro level (too small business units) as at meso-level (a patchwork of different organisations with overlapping competences). Finally, health care providers would like to be more involved in government initiatives and campaigns. Major facilitators put forward were the existing and well developed health services as well as the recent initiatives to promote chronic care and spread ICT. As such, the existing structures and initiatives must be considered as the basement of future change. The professional commitment of the providers towards their patients and the open mind towards the upcoming change were also put forward as essential facilitators. Finally, providers experience the patients’ tendencies to more empowerment and independence as a positive evolution. Discussion: The strength of this project is the involvement of a large number of Flemish primary care providers into a movement for better chronic care. It also listed essential barriers towards its implementation as well as key facilitators. Its major weakness is its scope, only based on the experience of primary health care providers without involvement of neither social workers, nor secondary care and expert opinion. However, the project enabled a landmark report for the Ministry of Health with key recommendations to successful future nation-wide implementation of chronic care.status: publishe

Separate MRI quantification of dispersed (ferritin-like) and aggregated (hemosiderin-like) storage iron

A new MRI method is proposed for separately quantifying the two principal forms of tissue storage (nonheme) iron: ferritin iron, a dispersed, soluble fraction that can be rapidly mobilized, and hemosiderin iron, an aggregated, insoluble fraction that serves as a long-term reserve. The method utilizes multiple spin echo sequences, exploiting the fact that aggregated iron can induce nonmonoexponential signal decay for multiple spin echo sequences. The method is validated in vitro for agarose phantoms, simulating dispersed iron with manganese chloride, and aggregated iron with iron oxide microspheres. To demonstrate feasibility for human studies, preliminary in vivo data from two healthy controls and six patients with transfusional iron overload are presented. For both phantoms and human subjects, conventional R 2 and R 2*relaxation rates are also measured in order to contrast the proposed method with established MRI iron quantification techniques. Quantification of dispersed (ferritin-like) iron may provide a new means of monitoring the risk of iron-induced toxicity in patients with iron overload and, together with quantification of aggregated (hemosiderin-like) iron, improve the accuracy of estimates for total storage iron. © 2010 Wiley-Liss, Inc.link_to_OA_fulltex