ETUDE DE LA CYTOTOXICITE ET DU STRESS OXYDANT INDUIT PAR UN ANTAGONISTE DU GABA, LA CIPROFLOXACINE

Dans cette etude nous preséntons les effets toxiques prooxydants d'un antibiotique du groupe des fluoroquinolones, la ciprofloxacine (CPR) dont les effets secondaires etaiént jusqu la attribues a son action antagoniste du GABA. Nous montrons que la CPR est cytotoxique a haute concentrations et induit une peroxydation lipidique pour des fibroblastes humains cutaneus normaux en culture ainsi que pour des astrocytes de rat en culture primaire. La pré-incubation de ces deux culture cellulaires avec de la vitamine E assure a la fois une forte protection contre la mort cellulaire et la peroxydation lipidique. L'incubation de microsomes cérébraux au hépatiques de rat avec la CPR induit une fort niveau de peroxydation lipidique et une diminition de la quantité des groupements thiols en même temps que la production de radicaux libres démontrée par RPE après piégeage par un agent spécifique de spin-trapping la 4-POBN. L'analyse du signal de RPE réléve un spectre caractéristique formé da six pics, correspondant à une radical carbone centré 4-POBN-derivé lipidique (aN= 15,44 G, aHb= 2,86 G). L'intensité du signal RPE se révèle proportionnelle à la dose de CPR et au temps d'incubation, et nécessite le fonctionnement du système CYP450 en présence de NADPH, comme le montre l'incubation induite par SKF 525A et ZnCl2. La formation du radical est de plus dépendante de la présence de Fer car elle est amplifiée par addition de ce métal et inhibée par des agents chélateurs comme la desferrioxamine au l'acide deethylénetriamine pentaacétique, ainsi que par la vitamin E son analogue hydrosoluble, le Trolox. L'analyse directe du mélange réactionnel microsomial en couplage HPLC-ESI MS, montre la présence de fragments compatibles avec le piégeage d'un radical "pentenyl" par la 4-POBN. D'autres signaux de spectrométrie de masse suggèrent la formation dans le milieu réactionnel de 4Ø N du métabolite oxo de la CPR.In this study, in vitro oxidative stress and lipid peroxidation inducing effects of the fluoroquinolone antibiotic, ciprofloxacin (CPR), the adverse effects of which has been attributed to its GABA antagonistic activity was investigated. CPR was found to be cytotoxic at high concentrations and induced significant lipid peroxidation in normal human fibroblast cell cultures, and primary cultures of rat astrocyte cells. Preincubation of both cell cultures with vitamin E provided significant protection against both cytotoxicity and induction of lipid peroxidation. Incubation of rat cerebral or liver microsomes with CPR induced significant level of lipid peroxidation and caused significant loss of cellular thiols, in addition to the production of radicals as shown by ESR-spin trapping with 4-POBN. The ESR analysis revealed a spectrum of a characteristic six-line and signal corresponding to a carbon-centered 4-POBN/lipid-derived radical (aN= 15,44 G, aHb= 2,86 G). The ESR signal intensity was dependent on the concentration of CPR and incubation time; radical generation required the presence of CYP450 activity and NADPH as shown with the incubation caused by SKF 525A and ZnCl2, and seemed to be dependent on iron. Iron chelators such as desferrioxaimine and DTPA, and vitamin E and its hydrosoluble analog Trolox inhibited the radical production while the addition of iron increased the signal intensity. The on-line HPLC-ESI MS analysis of microsomal incubation mixture showed that the mass spactra contained ions consistent with the trapping of the "pentenyl radical" by 4-POBN. Further analysis of the mass spectra suggested that a 4Ø N radical form of the oxo metabolite of CPR might have been produced in the microsomal mixture.GRENOBLE1-BU Médecine pharm. (385162101) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF

Expired air- co and urinary cotinine levels of the electronic cigarette users: Descriptive study from Turkey

The electronic cigarette (e-cigarette), which is accepted as a new market by the tobacco industry, is highly dependent on health and is addictive due to its nicotine content. Informing and raising awareness is extremely valuable to protect the identified risks of e-cigarette in society. The aim of this study was to determine the socio-demographic characteristics of volunteer e-cigarette users, to determine the causes of e-cigarette smoking, to identify some risks (nicotine, carbon monoxide). In this descriptive study, volunteer electronic cigarette smokers participated in the questionnaire, carbon monoxide was measured, urine sample was taken and directed to the toxicology laboratory for measurement of cotinine, and cotinine was measured in urine. Twenty volunteer e-cigarette smokers participated in the survey. Eighty five percent of the participants were male, 60% were married, 75% were college / university graduates, 80% were working, 65% of them were economical, 35% were good, 40% and 35% regularly use medicines. The median age of participants was 38.5 years, the youngest participant was 22, the oldest was 69 years old. Fifteen (75%) of the respondents stated that they were passively affected by tobacco smoke. Eight of these 15 (73%) were exposed to friends, eight (54%) were at home, eight (54%) were at cafes, etc., and four were exposed at work. The participants' main reasons for starting to smoke are friend influence and curiosity. Thirty percent of participants had tried e-cigarette before using e-cigarette, 90% used e-cigarette every day, e-cigarette was most frequently obtained from internet and friends / relatives, 79% did not use cigarette e-cigarette and all use nicotine. Participants' median e-cigarette smoking duration was 5.5 months; monthly e-cigarette expenditures are median 60 TL. Participants main reasons to smoke e-cigarette are to quit smoking, reduce smoking cigarettes and for reasons of cheapness. Eleven of the respondents (55%) stated that they never smoked together with e-cigarette but 9 (45%) smoked together with e-cigarette, but e-cigarette smoking significantly reduced the cigarette. Only 15% of the participants (three people) knew that smoking was harmful to health; only 45% of e-cigarette users knew that e-cigarette is addictive although they all use nicotine in their e-cigarettes. Of the 19 people who responded to the question 15 (79%) do not consider leaving e-cigarettes. Participants' carbon monoxide levels were measured as median 3, lowest 1, highest 22. Carbon monoxide level in 25% of participants was found to be above 7 ppm, which is used as threshold value in determining smokers. The levels of cotinine detected in urine samples are 709.9, lowest 318.6, highest 825.3 ng / ml. A moderate and statistically significant correlation was found between the amount of fluids used by the participants in one day (ml) and cotinine levels in urine specimens (Pearson correlation test, r = 0.511, p = 0.025). As a result, this study, in which nicotine exposure and increase in carbon monoxide and urine cotinine levels due to the use of e-cigarettes is documented, is an important proof of the country's scientific work on e-cigarettes. Preventive strategies should be strictly used for any tobacco products including e-cigarettes. Funding Statement: This project was funded by Hacettepe University, Scientific Research Projects Coordination Unit (Project nb. TAY-2016-9469)