114 research outputs found

    Defective transcription-coupled repair in Cockayne syndrome B mice is associated with skin cancer predisposition.

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    A mouse model for the nucleotide excision repair disorder Cockayne syndrome (CS) was generated by mimicking a truncation in the CSB(ERCC6) gene of a CS-B patient. CSB-deficient mice exhibit all of the CS repair characteristics: ultraviolet (UV) sensitivity, inactivation of transcription-coupled repair, unaffected global genome repair, and inability to resume RNA synthesis after UV exposure. Other CS features thought to involve the functioning of basal transcription/repair factor TFIIH, such as growth failure and neurologic dysfunction, are present in mild form. In contrast to the human syndrome, CSB-deficient mice show increased susceptibility to skin cancer. Our results demonstrate that transcription-coupled repair of UV-induced cyclobutane pyrimidine dimers contributes to the prevention of carcinogenesis in mice. Further, they suggest that the lack of cancer predisposition in CS patients is attributable to a global genome repair process that in humans is more effective than in rodents

    Mouse model for the DNA repair/basal transcription disorder Trichothiodystrophy reveals cancer predisposition.

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    Patients with the nucleotide excision repair (NER) disorder xeroderma pigmentosum (XP) are highly predisposed to develop sunlight-induced skin cancer, in remarkable contrast to photosensitive NER-deficient trichothiodystrophy (TTD) patients carrying mutations in the same XPD gene. XPD encodes a helicase subunit of the dually functional DNA repair/basal transcription complex TFIIH. The pleiotropic disease phenotype is hypothesized to be, in part, derived from a repair defect causing UV sensitivity and, in part, from a subtle, viable basal transcription deficiency accounting for the cutaneous, developmental, and the typical brittle hair features of TTD. To understand the relationship between deficient NER and tumor susceptibility, we used a mouse model for TTD that mimics an XPD point mutation of a TTD patient in the mouse germline. Like the fibroblasts from the patient, mouse cells exhibit a partial NER defect, evident from the reduced UV-induced DNA repair synthesis (residual repair capacity approximately 25%), limited recovery of RNA synthesis after UV exposure, and a relatively mild hypersensitivity to cell killing by UV or 7,12-dimethylbenz[a]anthracene. In accordance with the cellular studies, TTD mice exhibit a modestly increased sensitivity to UV-induced inflammation and hyperplasia of the skin. In striking contrast to the human syndrome, TTD mice manifest a dear susceptibility to UV- and 7,12-dimethylbenz[a]anthracene-induced skin carcinogenesis, albeit not as pronounced as the totally NER-deficient XPA mice. These findings open up the possibility that TTD is associated with a so far unnoticed cancer predisposition and support the notion that a NER deficiency enhances cancer susceptibility. These findings have important implications for the etiology of the human disorder and for the impact of NER on carcinogenesis

    How to promote healthy behaviours in patients? An overview of evidence for behaviour change techniques

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    To identify the evidence for the effectiveness of behaviour change techniques, when used by health-care professionals, in accomplishing health-promoting behaviours in patients. Reviews were used to extract data at a study level. A taxonomy was used to classify behaviour change techniques. We included 23 systematic reviews: 14 on smoking cessation, 6 on physical exercise, and 2 on healthy diets and 1 on both exercise and diets. None of the behaviour change techniques demonstrated clear effects in a convincing majority of the studies in which they were evaluated. Techniques targeting knowledge (n = 210 studies) and facilitation of behaviour (n = 172) were evaluated most frequently. However, self-monitoring of behaviour (positive effects in 56% of the studies), risk communication (52%) and use of social support (50%) were most often identified as effective. Insufficient insight into appropriateness of technique choice and quality of technique delivery hinder precise conclusions. Relatively, however, self-monitoring of behaviour, risk communication and use of social support are most effective. Health professionals should avoid thinking that providing knowledge, materials and professional support will be sufficient for patients to accomplish change and consider alternative strategies which may be more effective

    Appreciation and implementation of the Krachtvoer healthy diet promotion programme for 12- to 14- year-old students of prevocational schools

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    <p>Abstract</p> <p>Background</p> <p>Krachtvoer is a school-based healthy diet programme, developed in 2001 and revised in 2007 to meet the needs of particular segments of the target population as well as a wider target group. The main aims of the present process evaluation of the revised programme were to examine student and teacher appreciation of the programme, completeness of and adherence to its implementation, and relations between appreciation and completeness of implementation.</p> <p>Methods</p> <p>Data were collected among 22 teachers and 1117 students of 13 schools, using student evaluation forms, teacher logbooks, telephone interviews, and classroom observations.</p> <p>Results</p> <p>Results indicate favourable levels of teacher and student appreciation for the programme in general and the revised elements. Girls, first-year students and students with more favourable dietary intakes particularly appreciated individual programme elements. Levels of completeness of implementation were high, but several teachers did not adhere to the intended implementation period. Some moderately strong relations were found between teacher appreciation and completeness of implementation scores.</p> <p>Conclusion</p> <p>We conclude that the revisions have resulted in a programme that was appreciated well, also by the extended target group, and was implemented with a high degree of completeness. Teacher appreciation proved potentially important for completeness of implementation. We identified several aspects requiring improvement, indicating the importance of continued programme updates and repeated evaluation.</p

    The (cost-)effectiveness of an individually tailored long-term worksite health promotion programme on physical activity and nutrition: design of a pragmatic cluster randomised controlled trial

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    Cardiovascular disease is the leading cause of disability and mortality in most Western countries. The prevalence of several risk factors, most notably low physical activity and poor nutrition, is very high. Therefore, lifestyle behaviour changes are of great importance. The worksite offers an efficient structure to reach large groups and to make use of a natural social network. This study investigates a worksite health promotion programme with individually tailored advice in physical activity and nutrition and individual counselling to increase compliance with lifestyle recommendations and sustainability of a healthy lifestyle. METHODS: The study is a pragmatic cluster randomised controlled trial with the worksite as the unit of randomisation. All workers will receive a standard worksite health promotion program. Additionally, the intervention group will receive access to an individual Health Portal consisting of four critical features: a computer-tailored advice, a monitoring function, a personal coach, and opportunities to contact professionals at request. Participants are employees working for companies in the Netherlands, being literate enou

    Tissue specific mutagenic and carcinogenic responses in NER defective mouse models.

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    Several mouse models with defects in genes encoding components of the nucleotide excision repair (NER) pathway have been developed. In NER two different sub-pathways are known, i.e. transcription-coupled repair (TC-NER) and global-genome repair (GG-NER). A defect in one particular NER protein can lead to a (partial) defect in GG-NER, TC-NER or both. GG-NER defects in mice predispose to cancer, both spontaneous as well as UV-induced. As such these models (Xpa, Xpc and Xpe) recapitulate the human xeroderma pigmentosum (XP) syndrome. Defects in TC-NER in humans are associated with Cockayne syndrome (CS), a disease not linked to tumor development. Mice with TC-NER defects (Csa and Csb) are - except for the skin - not susceptible to develop (carcinogen-induced) tumors. Some NER factors, i.e. XPB, XPD, XPF, XPG and ERCC1 have functions outside NER, like transcription initiation and inter-strand crosslink repair. Deficiencies in these processes in mice lead to very severe phenotypes, like trichothiodystrophy (TTD) or a combination of XP and CS. In most cases these animals have a (very) short life span, display segmental progeria, but do not develop tumors. Here we will overview the available NER-related mouse models and will discuss their phenotypes in terms of (chemical-induced) tissue-specific tumor development, mutagenesis and premature aging features
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