Reduced CSF turnover and decreased ventricular Aβ42 levels are related

International audienceBACKGROUND: The appearance of Aβ42 peptide deposits is admitted to be a key event in the pathogenesis of Alzheimer's disease, although amyloid deposits also occur in aged non-demented subjects. Aβ42 is a degradation product of the amyloid protein precursor (APP). It can be catabolized by several enzymes, reabsorbed by capillaries or cleared into cerebrospinal fluid (CSF). The possible involvement of a decrease in CSF turnover in A4β2 deposit formation is up to now poorly known. We therefore investigated a possible relationship between a reduced CSF turnover and the CSF levels of the A4β2 peptide.To this aim, CSF of 31 patients with decreased CSF turnover were studied. These patients presented chronic hydrocephalus communicating or obstructive, which required surgery (ventriculostomy or ventriculo-peritoneal shunt). Nine subjects had idiopathic normal pressure hydrocephalus (iNPH), and the other 22 chronic hydrocephalus from other origins (oCH).The Aβ42 peptide concentration was measured by an ELISA test in 31 ventricular CSF samples and in 5 lumbar CSF samples from patients with communicating hydrocephalus. RESULTS: The 5 patients with lumbar CSF analysis had similar levels of lumbar and ventricular Aβ42. A significant reduction in Aβ42 ventricular levels was observed in 24 / 31 patients with hydrocephalus. The values were lower than 300 pg/ml in 5 out of 9 subjects with iNPH, and in 15 out of 22 subjects with oCH. CONCLUSION: The decrease of CSF Aβ42 seems to occur independently of the surgical hydrocephalus aetiology. This suggests that a CSF reduced turnover may play an important role in the decrease of CSF Aβ42 concentration

Osteoporosis treatment in patients over 75 years old with fractures living in nursing home

OBJECTIVE: Recommendations for the management of major fractures in institutionalized patients over 75 years old were updated by the GRIO (French group for research and information on osteoporosis) in 2012 and in 2018. This study is an evaluation of practices in osteoporosis management in institutionalized old patients. METHODS: Evaluation of diagnostic and therapeutic management in medical observations of all residents over 75 years old with a history of major fracture in 4 nursing homes. RESULTS: 105 residents were included with the prevalence of osteoporosis fracture of 32.1%. The most common fractures were hip fractures (60.9%) and vertebral fracture (45.8%). Treatments were: calcium supplementation (14.3% of residents), vitamin D (52.4%), rehabilitation (70.5%) and specific treatment (biphosphonates 11.4%). Complete management (calcium supplementation, vitamin D, physical activity and osteoporosis treatment) was found in 5 residents (4.7%). Few factors were related to complete treatment initiation. Residents initially managed in medicine departments were more treated than those in surgical wards (25.0 vs 6.5%; p = 0.0144) rather than those managed by specialists (rheumatologist or geriatrician: 8 vs 4; p \textless 0.001). Creatinine clearance was significantly higher in residents with calcium supplementation (52.7 +/- 27.9 vs 39.1 +/- 9.6; p = 0.0505). Regimen number tend to be higher in residents receiving vitamin D (8.9 +/- 2.7 vs 6.7 +/- 3.4; p = 0.0753). CONCLUSION: This evaluation of professional practices showed that only a minority of residents received complete anti-osteoporotic treatment despite their risk factor for fracture recurrence. Such an evaluation should be systematic at the entry in nursing home, given the number of falling residents

Mesure de la survie des macrophages alvéolaires après irradiation alpha pour l'évaluation de la toxicité des oxydes d'actinides inhalés

Nous avons mesuré la survie de macrophages alvéolaires de rat après une irradiation alpha réalisée in vitro à l'aide de sources électrodéposées de 239-Pu. La survie a été évaluée en mesurant, par puits de culture, le nombre de cellules adhérentes par unité de surface comparée àdes puits non irradiés. La relation dose-effet obtenue suit une fonction exponentielle de la fluence alpha émise par la source. Après mesure des surfaces projetées des cellules entières et de leurs noyaux par microscopie optique, et détermination de la forme cellulaire par microscopie confocale, un calcul dosimétrique a été effectué. Environ 550 alpha/cellule et 150 alpha/noyau induisent une létalité de 63 % des macrophages alvéolaires, soit une Do de l'ordre de 90 Gy pour la cellule ou le noyau. Ces résultats permettent d'évaluer la survie des macrophages in vivo après phagocytose d'oxydes d'actinides, en fonction de la taille et de l'activité alpha spécifique de la particule. Après inhalation, une létalité significative des macrophages alvéolaires serait induite pour des particules d'oxydes d'actinides de diamètre aérodynamique supérieur à 1 micron et d'activité spécifique supérieure à celle du 239-PuO2

Tribo-corrosion of coatings: a review

This paper reviews the available literature relating to the emerging research into the performance of coatings under combined wear and corrosion conditions. Understanding how coatings perform under these tribo-corrosion conditions is essential if the service life of equipment is to be predicted and to allow service life to be extended. Therefore, the tribo-corrosion performance of coatings deposited by a variety of techniques is discussed and the main mechanisms associated with their degradation under combined wear and corrosion highlighted. Coating composition, microstructure, defect level, adhesion, cohesion and substrate properties are seen as some of the critical elements in coating performance when subjected to tribo-corrosion contacts. The importance of post-coating deposition treatments such as laser resurfacing and sealing are also discussed. Interactions between wear and corrosion mechanisms are identified along with some models and mapping techniques that aim to inform coating selection and predict performance. Recent investigations into mono-layer as well as multilayered and functionally graded coatings are reviewed as candidates for wear–corrosion resistant surfaces. The review reveals the need for a more considered approach to tribo-corrosion testing and the way in which the results are analysed and presented. For example, the test conditions should be appropriate to the coating system under test; the level of in situ instrumentation deployed and the post-test analysis of in situ electrochemical data should be carefully selected as well as details given of the composition of any surface tribofilms formed and the identification of the degradation mechanisms