Adaptation of topoisomerase I paralogs to nuclear and mitochondrial DNA

Topoisomerase I is essential for DNA metabolism in nuclei and mitochondria. In yeast, a single topoisomerase I gene provides for both organelles. In vertebrates, topoisomerase I is divided into nuclear and mitochondrial paralogs (Top1 and Top1mt). To assess the meaning of this gene duplication, we targeted Top1 to mitochondria or Top1mt to nuclei. Overexpression in the fitting organelle served as control. Targeting of Top1 to mitochondria blocked transcription and depleted mitochondrial DNA. This was also seen with catalytically inactive Top1 mutants, but not with Top1mt overexpressed in mitochondria. Targeting of Top1mt to the nucleus revealed that it was much less able to interact with mitotic chromosomes than Top1 overexpressed in the nucleus. Similar experiments with Top1/Top1mt hybrids assigned these functional differences to structural divergences in the DNA-binding core domains. We propose that adaptation of this domain to different chromatin environments in nuclei and mitochondria has driven evolutional development and conservation of organelle-restricted topoisomerase I paralogs in vertebrates

Conférence générale de l'EAPR 2014, un succès international

National audienceDu 6 au 11 juillet, l'Association européenne pour la recherche sur la pomme de terre (EAPR) a organisé la 19e édition de sa conférence triennale en Belgique à Bruxelles. Cette conférence a rassemblé plus de 400 participants issus de 6 continents et de 56 pays différents

Bilan de l'expérimentation. Synthèse des analyses

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Les céphalées post-ponction durale: traitement et prévention

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Carotid blowout syndrome in patients with nasopharyngeal carcinoma: three cases

Carotid blowout syndrome (CBS) is a rare complication of radiation therapy for nasopharyngeal carcinoma (NPC), for which angiography is the gold standard for diagnosis and treatment. We report three NPC cases treated with irradiation and complicated by bleeding from the internal carotid artery. The first case presented with multiple episodes of limited nosebleeding followed by massive bleeding. Bleeding was initially stopped by internal carotid artery embolisation. A few months later, meningitis related to skull base osteoradionecrosis occurred and the patient died from sceptic shock. The second case was admitted to the hospital with severe repetitive epistaxis and despite several attempts to manage the bleeding, the patient passed away. The third case presented with a massive epistaxis that resolved itself without any treatment. Spontaneous occlusion of the internal carotid artery occurred without any neurological defects. A nasopharyngeal muscle flap was constructed to prevent meningitis. CBS is a rare but life-threatening complication that requires emergency treatment. Re-irradiation and skull base radioosteonecrosis are strong predisposing factors

Relationship between isometric strength of six lower limb muscle groups and motor skills among nursing home residents

peer reviewedAbstract: This research aimed to assess the correlation between isometric muscle strength of the lower limb and motor skills. This is a cross sectional study performed among volunteer nursing home residents included in the SENIOR (Sample of Elderly Nursing home Individuals: an Observational Research) cohort. The present analysis focused on isometric muscle strength of 6 lower limb muscle groups (i.e. knee extensors, knee flexors, hip abductors, hip extensors, ankle flexors and ankle extensors), assessed using a validated hand-held dynamometer (i.e. the MicroFET2 device), and motor skills evaluated using the Tinetti test, the Timed Up and Go test, the Short Physical Performance Battery test (SPPB) and the walking speed. The relationship between all these parameters was tested by means of a multiple correlation, adjusted on age, sex and body mass index. 450 nursing home residents (69.8% of women) with a mean age of 83.1±9.4 years were included in this study. Our results showed a significant inverse correlation between lower limb muscle strength and the time required to perform the TUG test or gait speed, except for ankle flexors and ankle extensors. The relationship between the Tinetti test or the SPPB score, and lower limb muscle strength was significant, except for ankle flexors and ankle extensors. In conclusion, a positive association between lower limb muscle strength of the four main muscle groups and motor skills of the elderly nursing residents was found in this research. Therefore, special attention should be given to these muscle groups during rehabilitation programs

Relationship between isometric strength of 6 muscle groups of the lower limbs and motor skills among nursing home residents

peer reviewe

Physical abilities of elderly nursing home residents: The SENIOR cohort

peer reviewe

Post-irradiated Carotid Blowout Syndrome in patients with Nasopharyngeal Tumor: about 3 cases

Introduction Rupture of the internal carotid artery (Carotid blowout syndrome) is a rare complication of irradiated nasopharyngeal tumor. We report three cases nasopharyngeal tumors treated with radiotherapy complicated with bleeding of the internal carotid artery presenting as a massive epistaxis. Case Series The first case presented a few episodes of small nose bleeding before a massive one. Internal carotid embolisation was performed to stop the bleeding. Unfortunately, few month later, he presented a meningitis related to skull base osteoradionecrosis and died from sceptic shock. The second case was transferred to our hospital with severe repetitive epistaxis that had been occurring for hours. No endovascular treatment was possible in his case and he died in intensive care unitthe dayof his admission. The thrid case presented one massive epistaxis which stopped without any treatment or compression. A spontaneous occlusion of his internal carotid artery occured without any neurological defects. He recently benefited from a nasopharyngeal muscle flap for the coverage of the carotid artery. These three patients all presented with a history of nasopharyngeal tumor handled by radiotherapy. Pathogenesis, treatment, and outcome are discussed on the light of a comprehensive literature review. Conclusions Carotid blowout syndrome secondary to radiation therapy is rare but life-threatening. Re-irradiation and skull base osteoradionecrosis are strong predisposing factors