A systematic review of longitudinal population-based studies on the predictors of smoking cessation in adolescent and young adult smokers

Le tabagisme est responsable de plus de 5 million de décès par an à travers le monde. En Suisse (2010), la prévalence de fumeurs chez les 14-19 ans était de 22% et la prévalence d'ex-fumeurs de 3%, taux qui reste relativement stable au fil des dernières années. La plupart des jeunes fumeurs désirant arrêter de fumer rencontrent des difficultés pour y parvenir. Les revues empiriques ont conclu que les programmes ayant pour but l'arrêt du tabagisme chez les jeunes ont une efficacité limitée. Afin de fournir une base solide de connaissances pour les programmes d'interventions contre le tabagisme, les déterminants de l'auto-cessation ont besoin d'être compris. Nous avons systématiquement recherché dans PUBMED et EMBASE des études longitudinales, basées sur la population, portant sur les déterminants de l'auto-cessation chez des adolescents et des jeunes adultes fumeurs. Nous avons passé en revue 4'502 titres et 871 abstracts, tous examinés indépendamment par deux et trois examinateurs, respectivement. Les critères d'inclusion étant : articles publiés entre janvier 1984 et août 2010, concernant les jeunes entre 10 et 29 ans et avoir une définition de cessation de fumer d'au moins 6 mois. Neuf articles ont été retenus pour une analyse détaillée. Les données suivantes ont été extraites de chaque article : le lieu de l'étude, la période étudiée, la durée du suivi, le nombre de collecte de données, la taille de l'échantillon, l'âge ou l'année scolaire des participants, le nombre de participants qui arrêtent de fumer, le status tabagique lors de la première collecte, la définition de cessation, les co-variantes et la méthode analytique. Le nombre d'études qui montrent une association significativement significative entre un déterminant et l'arrêt du tabagisme a été tabulé à partir de toutes les études qui ont évalués ce déterminant. Trois des neufs articles retenus ont défini l'arrêt du tabagisme comme une abstinence de plus de 6 mois et les six autres comme 12 mois d'abstinence. Malgré l'hétérogénéité des méthodes utilisées, cinq facteurs principaux ressortent comme prédicteur de l'arrêt du tabagisme : 1) ne pas avoir d'amis qui fument, 2) ne pas avoir l'intention de continuer de fumer dans le futur, 3) résister à la pression sociale, 4) être âgé de plus de 18 ans lors de la première cigarette, et 5) avoir un avis négatif au sujet du tabagisme. D'autres facteurs sont significatifs mais ne sont évalués que dans peu d'articles. La littérature au sujet des prédicteurs de cessation chez les adolescents et les jeunes adultes est peu développée. Cependant, nous remarquons que les facteurs que nous avons mis en évidence ne dépendent pas que de l'individu, mais aussi de l'environnement. La prévention du tabagisme peut se centrer sur les bienfaits de l'arrêt (p.ex., par rapport à l'asthme ou les performances sportives) et ainsi motiver les jeunes gens à songer d'arrêter de fumer. Une taxation plus lourde sur le prix des cigarettes peut être envisagée afin de retarder l'âge de la première cigarette. Les publicités anti-tabagiques (non sponsorisées par les entreprises de tabac) peuvent influencer la perception des jeunes par rapport au tabagisme, renforçant ou créant une attitude anti-tabagique. Les prochaines campagnes anti- tabac devraient donc tenir compte de ces différents aspects

Protective role of resveratrol on testicular germ cells in mice with testicular toxicity

WOS: 000416270600010Objective: The aim of the present study was to investigate the possible beneficial effects of resveratrol in mice subjected to vinyl cyclohexene dieposide (VCD) -induced testicular toxicity. Material and methods: A total of thirty-six Swiss albino male mice aged 28-days were used in the present study. The study was composed of two stages where mice which received or did not receive VCD (320 mg/kg/day) were administered resveratrol. The animals were assigned into control and resveratrol-treated groups in the first stage and into groups of VCD- and VCD+resveratrol-treated groups in the second stage. At the end of the experiments, relative testicular weight (TW/BW) and dry/wet weight of testis (TDW/TWW) were calculated. Histological analysis by hematoxylin and eosin (H&E) staining and immunohistochemical staining by BAX and Bcl-2 were performed. Serum testosterone, LH and FSH levels were measured by a commercially available ELISA kit. Results: Resveratrol caused a dose-dependent increase in TW/BW and decrease in TDW/TWW (p<0.05). Resveratrol at a dose of 20 mg/kg resulted in an improvement in testosterone, LH and FSH levels in mice with VCD-induced testicular toxicity (p<0.001). Resveratrol also improved apoptotic index and epithelial cell height of testicular seminipherous tubuli significantly after VCD exposure (p<0.001). Conclusion: Results of the present study suggest that resveratrol can be used as a protective and/or therapeutic agent particularly for cases with male infertility caused by testicular toxicity

Multifunctional Magnetic-fluorescent Nanocomposites for Biomedical Applications

Nanotechnology is a fast-growing area, involving the fabrication and use of nano-sized materials and devices. Various nanocomposite materials play a number of important roles in modern science and technology. Magnetic and fluorescent inorganic nanoparticles are of particular importance due to their broad range of potential applications. It is expected that the combination of magnetic and fluorescent properties in one nanocomposite would enable the engineering of unique multifunctional nanoscale devices, which could be manipulated using external magnetic fields. The aim of this review is to present an overview of bimodal “two-in-one” magnetic-fluorescent nanocomposite materials which combine both magnetic and fluorescent properties in one entity, in particular those with potential applications in biotechnology and nanomedicine. There is a great necessity for the development of these multifunctional nanocomposites, but there are some difficulties and challenges to overcome in their fabrication such as quenching of the fluorescent entity by the magnetic core. Fluorescent-magnetic nanocomposites include a variety of materials including silica-based, dye-functionalised magnetic nanoparticles and quantum dots-magnetic nanoparticle composites. The classification and main synthesis strategies, along with approaches for the fabrication of fluorescent-magnetic nanocomposites, are considered. The current and potential biomedical uses, including biological imaging, cell tracking, magnetic bioseparation, nanomedicine and bio- and chemo-sensoring, of magnetic-fluorescent nanocomposites are also discussed

Nanomaterials for Neural Interfaces

This review focuses on the application of nanomaterials for neural interfacing. The junction between nanotechnology and neural tissues can be particularly worthy of scientific attention for several reasons: (i) Neural cells are electroactive, and the electronic properties of nanostructures can be tailored to match the charge transport requirements of electrical cellular interfacing. (ii) The unique mechanical and chemical properties of nanomaterials are critical for integration with neural tissue as long-term implants. (iii) Solutions to many critical problems in neural biology/medicine are limited by the availability of specialized materials. (iv) Neuronal stimulation is needed for a variety of common and severe health problems. This confluence of need, accumulated expertise, and potential impact on the well-being of people suggests the potential of nanomaterials to revolutionize the field of neural interfacing. In this review, we begin with foundational topics, such as the current status of neural electrode (NE) technology, the key challenges facing the practical utilization of NEs, and the potential advantages of nanostructures as components of chronic implants. After that the detailed account of toxicology and biocompatibility of nanomaterials in respect to neural tissues is given. Next, we cover a variety of specific applications of nanoengineered devices, including drug delivery, imaging, topographic patterning, electrode design, nanoscale transistors for high-resolution neural interfacing, and photoactivated interfaces. We also critically evaluate the specific properties of particular nanomaterials—including nanoparticles, nanowires, and carbon nanotubes—that can be taken advantage of in neuroprosthetic devices. The most promising future areas of research and practical device engineering are discussed as a conclusion to the review.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/64336/1/3970_ftp.pd

Interactions between cells and functionalized nanoparticles

In this present thesis Superparamagnetic Iron Oxide Nanoparticles (SPIONs) with 9 nm in diameter were selected as nanocarriers in order to study their potential application as drug delivery systems. Therefore the aim of the study was to demonstrate the proof of concept by establishing an efficient system of drug delivery, which would be a valuable tool in biomedical applications, such as the treatement of cancer, by reducing the side effects due to administration of a high concentration of therapeutic agents. As demonstrated in a previous study, the uptake of SPIONs by tumoral human cells was enhanced by the presence of amino groups on their surface. The stabilization of SPIONs were then performed and optimized by the coating of poly(vinylalcohol) and poly(vinylalcohol/vinylamine). Such nanoparticles were known as aminoPVA-SPIONs. The toxicity and the inflammatory reaction of aminoPVA-SPIONs were evaluated in order to establish their potentiel use in the human body. The results demonstrated that the human cells were able to invaginate aminoPVA-SPIONS without revealing any toxicity and inflammatory reaction. The analysis by transmission electron microscopy (TEM), scanning electron microscopy (SEM), cryo-TEM, confocal microscopy and histological staining (i.e. Prussian Blue) showed that the iron oxide core of SPIONs were located in the cytoplasm of cells and concentrated in vesicles. The evaluation of the mechanism of uptake of aminoPVA-SPIONs revealed that their uptake by monolayer cell culture was performed via an active mechanism, which was achieved by a clathrin-mediated endocytosis. Consequently, it was suggested that aminoPVA-SPIONs were good candidates as nanocarriers in drug delivery systems, which were able to reach the cytoplasm of cells. Their incubation with three-dimensional models mimicing tissues, such as differentiated rat brain cell-derived aggregates and spheroids, revealed that aminoPVA-SPIONs were able to invade into deep cell layers according to the stage of growth of these models. In the view of these promising results, drug-SPIONs were prepared by the functionalization of aminoPVA-SPIONs via a biological labile chemical bond by one of these three antineoplastic agents, which are widely used in clinical practice: 5-fluorourdine (Fur) (an antimetabolite), or camptothecin (CPT) (a topoisomerase inhibitor) or doxorubicin (DOX) (an anthracycline which interfere with DNA). The results shown that drug-SPIONs were internalized by human melanoma cells, as it was expected due the previous results with aminoPVA-SPIONs, and in addition they were active as anticancer agents, suggesting the efficient release of the drug from the drug-SPIONs. The results with CPT-SPIONs were the most promising, whereas DOX- SPIONs did not demonstrate a prononced activity of DOX. In conclusion, the results demonstrated that functionalized iron oxide nanoparticles are a promising tool in order to deliver therapeutic agents. - Dans le cadre de ce travail de thèse, les nanoparticules superparamagnétiques d'oxyde de fer (SPIONs) ayant un diamètre de 9 nm ont été choisies, afin d'étudier leur éventuelle utilisation dans un système de délivrance d'agents thérapeutiques. Ainsi le but de la thèse est de démontrer la faisabilité de fabriquer un système efficace de délivrance d'agents thérapeutiques, qui serait un outil intéressant dans le cadre d'une utilisation biomédicale, par exemple lors du traitement du cancer, qui pourrait réduire les effets secondaires provoqués par le dosage trop élevé de médicaments. Comme il a été démontré dans une précédente étude, l'invagination des SPIONs par des cellules humaines cancéreuses est améliorée par la présence de groupes fonctionnels amino à leur surface. La stabilisation des SPIONs est ainsi effectuée et optimisée par l'enrobage de poly(vinylalcool) et de (poly(vinylalcool/vinylamine), qui sont connues sous le nom de aminoPVA-SPIONs. La toxicité et la réaction inflammatoire des aminoPVA-SPIONs ont été évaluées dans le but de déterminer leur potentielle utilisation dans le corps humain. Les résultats démontrèrent que les cellules humaines sont capables d'invaginer les aminoPVAS-SPIONs sans induire une réaction toxique ou inflammatoire. L'analyse par la microscopie électronique en transmission électronique (TEM), la microscopie électronique à balayage (SEM), le cryo-microscopie électronique (SEM), la microscopie confocale et la coloration histologique (par ex, le bleu de Prusse) a montré que l'oxyde de fer des SPIONs est localisé dans le cytoplasme des cellules et est concentré dans des vesicules. L'évaluation du méchanisme d'invagination des aminoPVA-SPIONs ont révélé que leur invagination par des monocultures de cellules est effectué par un méchanisme actif, contrôlé par une endocytose induite par les clathrins. Par conséquent, les aminoPVA-SPIONs sont de bons candidats en tant que transporteurs (nanocamers) dans un système de délivrance d'agents thérapeuthique, capable d'atteindre le cytoplasme des cellules. Leur incubation avec des modèles tridimenstionnels imitant les tissues, tels que les aggrégats de cellules de cerveau différenciées et les sphéroïdes, a montré que les aminoPVA-SPIONs sont capable de pénétrer dans les couches profondes des modèles, selon l'état d'avancement de leur croissance. En vue de ces résultats prometteurs, les drug-SPIONs ont été préparés en fonctionalisant les aminoPVA-SPIONs par le biai d'une liaison chimique labile par un des trois agents thérapeutiques, déjà utilisé en pratique : 5-fluorourdine (Fur) (un antimétabolite), or camptothecin (CPT) (un inhibiteur de la topoisomerase) or doxorubicin (DOX) (un anthracycline qui interfère avec le DNA). Les résultats ont montré que les drug-SPIONs sont capable d'être internalisés par les mélanomes, comme il a été attendu d'après les résultats obtenus précédemment avec les aminoPVA-SPIONs, et de plus, les drug-SPIONs sont actifs, ce qui suggère un relargage efficace de l'agent thérapeutique du drug-SPIONs. Les résultats obtenus avec les CPT-SPIONs sont les plus prometteurs, tandis que ceux avec les DOX-SPIONs, ce n'est pas le cas, dont l'activité thérapeutique de DOX n'a pas été aussi efficace. En conclusion, les résultats ont pu démontrer que les nanoparticules d'oxyde de fer fonctionnalisées sont un outil prometteur dans la délivrance d'agents thérapeutiques

Evaluation of uptake and transport of cationic and anionic ultrasmall iron oxide nanoparticles by human colon cells.

Nanoparticles (NPs) are in clinical use or under development for therapeutic imaging and drug delivery. However, relatively little information exists concerning the uptake and transport of NPs across human colon cell layers, or their potential to invade three-dimensional models of human colon cells that better mimic the tissue structures of normal and tumoral colon. In order to gain such information, the interactions of biocompatible ultrasmall superparamagnetic iron oxide nanoparticles (USPIO NPs) (iron oxide core 9-10 nm) coated with either cationic polyvinylamine (aminoPVA) or anionic oleic acid with human HT-29 and Caco-2 colon cells was determined. The uptake of the cationic USPIO NPs was much higher than the uptake of the anionic USPIO NPs. The intracellular localization of aminoPVA USPIO NPs was confirmed in HT-29 cells by transmission electron microscopy that detected the iron oxide core. AminoPVA USPIO NPs invaded three-dimensional spheroids of both HT-29 and Caco-2 cells, whereas oleic acid-coated USPIO NPs could only invade Caco-2 spheroids. Neither cationic aminoPVA USPIO NPs nor anionic oleic acid-coated USPIO NPs were transported at detectable levels across the tight CacoReady? intestinal barrier model or the more permeable mucus-secreting CacoGoblet? model

A systematic review of longitudinal population-based studies on the predictors of smoking cessation in adolescent and young adult smokers.

OBJECTIVE: To describe the determinants of self-initiated smoking cessation of duration of at least 6 months as identified in longitudinal population-based studies of adolescent and young adult smokers. METHODS: A systematic search of the PubMed and EMBASE databases using smoking, tobacco, cessation, quit and stop as keywords was performed. Limits included articles related to humans, in English, published between January 1984 and August 2010, and study population aged 10-29 years. A total of 4502 titles and 871 abstracts were reviewed independently by 2 and 3 reviewers, respectively. Nine articles were retained for data abstraction. Data on study location, timeframe, duration of follow-up, number of data collection points, sample size, age/grade of participants, number of quitters, smoking status at baseline, definition of cessation, covariates and analytic method were abstracted from each article. The number of studies that reported a statistically significant association between each determinant investigated and cessation were tabulated, from among all studies that assessed the determinant. RESULTS: Despite heterogeneity in methods across studies, five factors robustly predicted quitting across studies in which the factor was investigated: not having friends who smoke, not having intentions to smoke in the future, resisting peer pressure to smoke, being older at first use of cigarette and having negative beliefs about smoking. CONCLUSIONS: The literature on longitudinal predictors of cessation in adolescent and young adult smokers is not well developed. Cessation interventions for this population will remain less than optimally effective until there is a solid evidence base on which to develop interventions

Interaction of cationic ultrasmall superparamagnetic iron oxide nanoparticles with human melanoma cells.

Ultrasmall superparamagnetic iron oxide nanoparticles (USPIONs) are currently under development for the intracellular delivery of therapeutics. However, the mechanisms of cellular uptake and the cellular reaction to this uptake, independent of therapeutics, are not well defined. The interactions of biocompatible cationic aminoUSPIONs with human cells was studied in 2D and 3D cultures using biochemical and electron microscopy techniques. AminoUSPIONs were internalized by human melanoma cells in 2D and 3D cultures. Uptake was clathrin mediated and the particles localized in lysosomes, inducing activation of the lysosomal cathepsin D and decreasing the expression of the transferrin receptor in human melanoma cells and/or skin fibroblasts. AminoUSPIONs deeply invaded 3D spheroids of human melanoma cells. Thus, aminoUSPIONs can invade tumors and their uptake by human cells induces cell reaction