Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 45
Filtrar
1.
Nicotine Tob Res ; 23(3): 462-470, 2021 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-32770246

RESUMO

INTRODUCTION: The QuitNic pilot trial aimed to test the feasibility of providing a nicotine vaping product (NVP) compared with combination nicotine replacement therapy (NRT) to smokers upon discharge from a smoke-free residential substance use disorder (SUD) treatment service. METHODS: QuitNic was a pragmatic two-arm randomized controlled trial. At discharge from residential withdrawal, 100 clients received telephone Quitline behavioral support and either 12-week supply of NRT or an NVP. Treatment adherence and acceptability, self-reported abstinence, cigarettes smoked per day (CPD), frequency of cravings, and severity of withdrawal symptoms were assessed at 6 and 12 weeks. Results are reported for complete cases and for abstinence outcomes, penalized imputation results are reported where missing is assumed smoking. RESULTS: Retention on was 63% at 6 weeks and 50% at 12 weeks. At 12 weeks, 68% of the NRT group reported using combination NRT while 96% of the NVP group used the device. Acceptability ratings for the products were high in both groups. At 12 weeks, 14% of the NVP group and 18% of the NRT group reported not smoking at all in the last 7 days. Mean CPD among continued smokers decreased significantly between baseline to 12 weeks in both groups; from 19.91 to 4.72 for the NVP group (p < .001) and from 20.88 to 5.52 in the NRT group (p < .001). Cravings and withdrawal symptoms significantly decreased for both groups. CONCLUSIONS: Clients completing residential withdrawal readily engaged with smoking cessation post-treatment when given the opportunity. Further research is required to identify the most effective treatments postwithdrawal for this population at elevated risk of tobacco-related harm. TRIAL REGISTRATION NUMBER: ACTRN12617000849392. IMPLICATIONS: This pilot study showed that smoking cessation support involving options for nicotine replacement and Quitline-delivered cognitive behavioral counseling is attractive to people after they have been discharged from SUD treatment. Both nicotine vaping products and nicotine replacement therapies were highly acceptable and used by participants who reported reductions in cravings for cigarettes and perceptions of withdrawal symptoms and reductions in number of cigarettes smoked. Some participants self-reported abstinence from cigarettes-around one in five reported having quit smoking cigarettes at 12 weeks postdischarge. The results have significant public health implications for providing quit support following discharge from SUD treatment.


Assuntos
Sistemas Eletrônicos de Liberação de Nicotina/estatística & dados numéricos , Agonistas Nicotínicos/administração & dosagem , Abandono do Hábito de Fumar/métodos , Síndrome de Abstinência a Substâncias/terapia , Dispositivos para o Abandono do Uso de Tabaco/estatística & dados numéricos , Vaping/epidemiologia , Adulto , Assistência ao Convalescente , Terapia Comportamental , Aconselhamento , Feminino , Humanos , Masculino , Agonistas Nicotínicos/análise , Projetos Piloto , Resultado do Tratamento
2.
J Med Toxicol ; 16(4): 452-457, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32180139

RESUMO

INTRODUCTION: Cigarettes and other tobacco products may be extinguished by submersion in liquids in beverage cans or bottles. Cases of nicotine poisoning in children have been reported following ingestion of such liquids. The aim of this study is to analyze the variability of nicotine concentrations with respect to number of cigarettes immersed and the duration of immersion in a soda can METHODS: One unsmoked cigarette was immersed in a cola containing soda can. Three separate samples of the mixture were obtained at different intervals of time post immersion up to 1 week. At the same time, a set of four cola cans were immersed with an increasing number of unsmoked cigarettes and samples obtained. All the samples were then analyzed for nicotine concentrations using liquid chromatography-mass spectrometry. RESULTS: The mean concentration of nicotine measured over the course of 6 hours from one full cigarette in 55 ml of a cola beverage was 0.48 mg/ml. Nicotine concentrations steadily increased in the first 6 hours following submersion, after which, the levels plateaued (r = 0.530, n = 18, p = 0.024). There was a strong positive correlation between nicotine concentrations and the number of cigarettes (r = 0.967, n = 12, p = 3e-7). CONCLUSIONS: The mean concentration of nicotine measured over the course of 6 hours from one immersed cigarette can be potentially toxic especially to children. Nicotine concentrations are positively correlated with the number of cigarettes and time of immersion.


Assuntos
Bebidas Gaseificadas , Nicotina/análise , Agonistas Nicotínicos/análise , Produtos do Tabaco/análise , Cromatografia Líquida , Espectrometria de Massas por Ionização por Electrospray , Fatores de Tempo
3.
Arch Toxicol ; 94(6): 1985-1994, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32189038

RESUMO

The popularity and the high nicotine content of the American pod e-cigarette JUUL have raised many concerns. To comply with European law, the nicotine concentration in the liquids of the European version, which has been recently released on the market, is limited to below 20 mg/mL. This limit can possibly be circumvented by technological adjustments that increase vaporization and consequently, elevate nicotine delivery. In this study, we compare vapor generation and nicotine delivery of the initial European version, a modified European version, and the original American high-nicotine variant using a machine vaping set-up. Additionally, benzoic acid and carbonyl compounds are quantified in the aerosol. Further, concentrations of nicotine, benzoic acid, propylene glycol, and glycerol, along with the density and pH value of JUUL e-liquids have been assessed. Whereas the initial European version did not compensate for the low nicotine content in the liquid, we provide evidence for an increased vaporization by the modified European version. As a consequence, nicotine delivery per puff approximates the American original. Notably, this is not associated with an increased generation of carbonyl compounds. Our data suggest a similar addictiveness of the enhanced European version and the original American product.


Assuntos
Vapor do Cigarro Eletrônico/análise , Sistemas Eletrônicos de Liberação de Nicotina , Nicotina/análise , Agonistas Nicotínicos/análise , Vaping , Aerossóis , Qualidade de Produtos para o Consumidor , Vapor do Cigarro Eletrônico/efeitos adversos , Europa (Continente) , Humanos , Nicotina/efeitos adversos , Agonistas Nicotínicos/efeitos adversos , Medição de Risco , Vaping/efeitos adversos
5.
Harm Reduct J ; 15(1): 50, 2018 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-30285882

RESUMO

BACKGROUND: Article 10 of the World Health Organization Framework Convention on Tobacco Control states the need for industry disclosure of tobacco contents and emissions. Currently, the profiles of key tobacco compounds in legal and illegal cigarettes are largely unknown. We aimed to analyze and compare concentrations of nicotine, nitrosamines, and humectants in legal and illegal cigarettes collected from a representative sample of smokers. METHODS: Participants of the International Tobacco Control cohort provided a cigarette pack of the brand they smoked during the 2014 wave. Brands were classified as legal or illegal according to the Mexican legislation. Nicotine, nitrosamines, glycerol, propylene glycol, and pH were quantified in seven randomly selected packs of each brand. All analyses were done blinded to legality status. Average concentrations per brand and global averages for legal and illegal brands were calculated. Comparisons between legal and illegal brands were conducted using t tests. RESULTS: Participants provided 76 different brands, from which 6.8% were illegal. Legal brands had higher nicotine (15.05 ± 1.89 mg/g vs 12.09 ± 2.69 mg/g; p < 0001), glycerol (12.98 ± 8.03 vs 2.93 ± 1.96 mg/g; p < 0.001), and N-nitrosanatabine (NAT) (1087.5 ± 127.0 vs 738.5 ± 338 ng/g; p = 0.006) concentrations compared to illegal brands. For all other compounds, legal and illegal brands had similar concentrations. CONCLUSION: Compared to illegal cigarettes, legal brands seem to have higher concentrations of nicotine, NAT, and glycerol. Efforts must be made to implement and enforce Article 10 of the Framework Convention on Tobacco Control to provide transparent information to consumers, regulators, and policy-makers; and to limit cigarette engineering from the tobacco industry.


Assuntos
Higroscópicos/análise , Nicotina/análise , Agonistas Nicotínicos/análise , Nitrosaminas/análise , Produtos do Tabaco/análise , Comércio/legislação & jurisprudência , Crime , México , Produtos do Tabaco/legislação & jurisprudência
6.
Drug Test Anal ; 9(6): 944-948, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27943582

RESUMO

Recently, a variety of new tobacco-free-nicotine, TFN, products have been commercialized as e-liquids. Tobacco-derived nicotine contains predominantly (S)-(-)-nicotine, whereas TFN products may not. The TFN products are said to be cleaner, purer substances, devoid of toxic components that come from the tobacco extraction process. A variety of commercial tobacco and TFN products were analyzed to identify the presence and composition of each nicotine enantiomer. A rapid and effective enantiomeric separation of nicotine has been developed using a modified macrocyclic glycopeptide bonded to superficially porous particles. The enantiomeric assay can be completed in <2 min with high resolution and accuracy using high performance liquid chromatography with electrospray ionization mass spectrometry. The results of this study suggest the need for pharmacological studies of (R)-(+)-nicotine, which is present in much greater quantities in commercial TFN products compared to commercial tobacco-derived products. Such studies are required by the FDA for new enantiomeric pharmacological products. Copyright © 2016 John Wiley & Sons, Ltd.


Assuntos
Nicotina/análise , Agonistas Nicotínicos/análise , Cromatografia Líquida de Alta Pressão , Sistemas Eletrônicos de Liberação de Nicotina , Glicopeptídeos/química , Espectrometria de Massas por Ionização por Electrospray , Estereoisomerismo , Nicotiana/química
7.
Regul Toxicol Pharmacol ; 79: 64-73, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27181452

RESUMO

The use of very low nicotine tobacco cigarettes is currently being investigated as a possible harm reduction strategy. Here, we report the smoke chemistry, toxicity, and physical characteristics of very low nicotine cigarettes that were made using blended tobacco processed through a supercritical CO2 fluid extraction, which resulted in elimination of 96% of nicotine content (denicotinized (denic) tobacco). Three types of test cigarettes (TCs) were manufactured with tobacco filler containing 100% denic tobacco (TC100), 50% denic tobacco and 50% unextracted tobacco (TC50/50), and 100% unextracted tobacco (TC0). Mainstream smoke (MS) was generated for measurement of 46 analytes and cytotoxicity and mutagenicity determination. Analysis of physical characteristics of TCs demonstrated they were well made with <5% variability among cigarettes for most parameters measured. We observed significant changes in the levels of smoke constituents, including decreases in formaldehyde, nitrosamines, and phenol, and increases in aliphatic hydrocarbons, aliphatic nitrogen compounds, aromatic amines, halogen compounds, and metals. Use of denic tobacco resulted in changes in the chemical composition of MS, but these changes did not modify biological activity as measured in the mutagenicity and cytotoxicity assays.


Assuntos
Nicotiana/química , Nicotina/análise , Agonistas Nicotínicos/análise , Fumaça/análise , Fumar , Produtos do Tabaco/análise , Células 3T3 , Animais , Cromatografia com Fluido Supercrítico , Qualidade de Produtos para o Consumidor , DNA Bacteriano/efeitos dos fármacos , DNA Bacteriano/genética , Fibroblastos/efeitos dos fármacos , Fibroblastos/patologia , Humanos , Camundongos , Mutagênese , Testes de Mutagenicidade , Mutação , Nicotina/toxicidade , Agonistas Nicotínicos/toxicidade , Medição de Risco , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/genética , Fumaça/efeitos adversos , Fumar/efeitos adversos , Nicotiana/toxicidade , Produtos do Tabaco/toxicidade
8.
Regul Toxicol Pharmacol ; 79: 144-148, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27058761

RESUMO

Electronic cigarette use has rapidly increased in recent years. In assessing their safety, and in view of coming regulations, trace elements (TE) are among the potentially toxic compounds required to be evaluated in electronic cigarette refill fluids ("e-liquids"). An analytical method using inductively coupled plasma with mass spectrometric detection (ICP-MS) was developed and rigorously validated in order to determine concentrations of 15 TE in 54 e-liquids from a French brand. Despite a significant matrix effect from the main e-liquid constituents, and difficulties related to the current lack of reference materials, our method demonstrated satisfactory linearity, precision and robustness, and permitted the quantification of low concentrations of these 15 elements: lower limits of quantification (LLQ) obtained were ≤4 ppb for all elements except for Ni, Cu and Zn (16 ppb, 20 ppb and 200 ppb, respectively). All TE concentrations in all tested samples were <510 ppb, mostly near or below the LLQs. This method is transposable and is timely for laboratories seeking to meet a prospective demand in light of current or future regulations.


Assuntos
Contaminação de Medicamentos , Sistemas Eletrônicos de Liberação de Nicotina , Espectrometria de Massas/métodos , Agonistas Nicotínicos/análise , Abandono do Hábito de Fumar/métodos , Solventes/análise , Oligoelementos/análise , Calibragem , Limite de Detecção , Modelos Lineares , Espectrometria de Massas/normas , Padrões de Referência , Reprodutibilidade dos Testes
10.
Tob Control ; 25(e1): e10-5, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25877377

RESUMO

BACKGROUND: Most e-cigarette liquids contain flavour chemicals. Flavour chemicals certified as safe for ingestion by the Flavor Extracts Manufacturers Association may not be safe for use in e-cigarettes. This study identified and measured flavour chemicals in 30 e-cigarette fluids. METHODS: Two brands of single-use e-cigarettes were selected and their fluids in multiple flavour types analysed by gas chromatography/mass spectrometry. For the same flavour types, and for selected confectionary flavours (eg, bubble gum and cotton candy), also analysed were convenience samples of e-cigarette fluids in refill bottles from local 'vape' shops and online retailers. RESULTS: In many liquids, total flavour chemicals were found to be in the ∼1-4% range (10-40 mg/mL); labelled levels of nicotine were in the range of 0.6-2.4% (6 to 24 mg/mL). A significant number of the flavour chemicals were aldehydes, a compound class recognised as 'primary irritants' of mucosal tissue of the respiratory tract. Many of the products contained the same flavour chemicals: vanillin and/or ethyl vanillin was found in 17 of the liquids as one of the top three flavour chemicals, and/or at ≥0.5 mg/mL. CONCLUSIONS: The concentrations of some flavour chemicals in e-cigarette fluids are sufficiently high for inhalation exposure by vaping to be of toxicological concern. Regulatory limits should be contemplated for levels of some of the more worrisome chemicals as well as for total flavour chemical levels. Ingredient labeling should also be required.


Assuntos
Sistemas Eletrônicos de Liberação de Nicotina , Aromatizantes/análise , Nicotina/análise , Agonistas Nicotínicos/análise , Abandono do Hábito de Fumar/métodos , Vaping , Composição de Medicamentos , Aromatizantes/efeitos adversos , Cromatografia Gasosa-Espectrometria de Massas , Medição de Risco , Volatilização
11.
Regul Toxicol Pharmacol ; 74: 1-11, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26617410

RESUMO

E-cigarettes are gaining popularity in the U.S. as well as in other global markets. Currently, limited published analytical data characterizing e-cigarette formulations (e-liquids) and aerosols exist. While FDA has not published a harmful and potentially harmful constituent (HPHC) list for e-cigarettes, the HPHC list for currently regulated tobacco products may be useful to analytically characterize e-cigarette aerosols. For example, most e-cigarette formulations contain propylene glycol and glycerin, which may produce aldehydes when heated. In addition, nicotine-related chemicals have been previously reported as potential e-cigarette formulation impurities. This study determined e-liquid formulation impurities and potentially harmful chemicals in aerosols of select commercial MarkTen(®) e-cigarettes manufactured by NuMark LLC. The potential hazard of the identified formulation impurities and aerosol chemicals was also estimated. E-cigarettes were machine puffed (4-s duration, 55-mL volume, 30-s intervals) to battery exhaustion to maximize aerosol collection. Aerosols analyzed for carbonyls were collected in 20-puff increments to account for analyte instability. Tobacco specific nitrosamines were measured at levels observed in pharmaceutical grade nicotine. Nicotine-related impurities in the e-cigarette formulations were below the identification and qualification thresholds proposed in ICH Guideline Q3B(R2). Levels of potentially harmful chemicals detected in the aerosols were determined to be below published occupational exposure limits.


Assuntos
Aldeídos/análise , Sistemas Eletrônicos de Liberação de Nicotina , Nicotina/análise , Agonistas Nicotínicos/análise , Nitrosaminas/análise , Aerossóis , Aldeídos/efeitos adversos , Amônia/análise , Arsênio/análise , Cádmio/análise , Química Farmacêutica , Contaminação de Medicamentos , Estabilidade de Medicamentos , Sistemas Eletrônicos de Liberação de Nicotina/efeitos adversos , Humanos , Nicotina/efeitos adversos , Agonistas Nicotínicos/efeitos adversos , Nitrosaminas/efeitos adversos , Medição de Risco , Volatilização
12.
Environ Sci Pollut Res Int ; 22(18): 14000-6, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25956519

RESUMO

The aim of this study was to compare estimation of nicotine use in Slovakia (SR) and the Czech Republic (CR) based on cotinine analysis in wastewater from seven selected wastewater treatment plants (WWTPs) with conventional estimation based on tobacco product sales. Urinary bio-markers of nicotine use were analyzed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The study was performed concurrently at all the WWTPs (from 11 to 18 March 2014). Representative 24 h composite samples were analyzed with on line SPE/LC-MS/MS method. Based on the average residence time of wastewater in the sewers and the average time in the sampling device, specific correction coefficients were designed to improve estimation of nicotine consumption. Nicotine ingestion level was back-calculated and expressed as mass of pure drug consumed per day and per 1000 inhabitants for selected cities of both countries (mean, 2.2 g for Piestany and 8.0 g for Nitra, respectively). Consequently, the cigarette consumption results were recalculated for each country separately and compared with the data of both national statistical offices (2362 cigarettes/year/person--SR and 2088 cigarettes/year/person--CR). Our results highly correspond to the data of national statistical offices (up to 99.9% in SR and to 96% in CR). The average amount of money invested in cigarette sales was estimated in the capitals of both countries. It is about 1 million EUR/day for Prague and about 0.3 million EUR/day for Bratislava. The calculation of nicotine consumption, utilizing a specific correction coefficient, is the correct way to obtain more accurate data in drug studies of this kind, thus allowing a better drug abuse assessment.


Assuntos
Nicotina/análise , Agonistas Nicotínicos/análise , Fumar/epidemiologia , Águas Residuárias/análise , Cromatografia Líquida , Cidades , República Tcheca/epidemiologia , Humanos , Eslováquia/epidemiologia , Espectrometria de Massas em Tandem
13.
Int J Legal Med ; 127(1): 85-91, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22673800

RESUMO

The smoking cessation agent varenicline acts as a partial agonist on α(4)ß(2) nicotinic acetylcholine receptors. Although debated, several reports have linked varenicline therapy to an increased risk of suicidal thoughts and/or suicide. In addition, several non-fatal overdose cases have been reported. In this report, we utilised a sample preparation procedure suitable for postmortem samples and gas chromatography coupled to mass spectrometry to analyse samples obtained from a suicidal case in which ingestion of an overdose of varenicline had occurred. Extremely high concentrations of varenicline (>250 ng/ml) were detected in the blood of the deceased, in addition to high concentrations in urine and vitreous humour. To the best of our knowledge, similar high concentrations have not been reported yet. Although, with respect to the mechanism of death in this case, confounding factors were concomitant ethanol consumption and, importantly, potentially fatal hypothermia, this is the first report of a fatality associated with the ingestion of an overdose of varenicline.


Assuntos
Benzazepinas/intoxicação , Overdose de Drogas , Agonistas Nicotínicos/intoxicação , Quinoxalinas/intoxicação , Suicídio , Adulto , Benzazepinas/análise , Depressores do Sistema Nervoso Central/análise , Etanol/análise , Toxicologia Forense , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Hipotermia/patologia , Masculino , Agonistas Nicotínicos/análise , Quinoxalinas/análise , Vareniclina , Corpo Vítreo/química
14.
J Pharmacol Exp Ther ; 343(2): 434-40, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22899751

RESUMO

We have developed a new radioligand binding assay method to measure the concentration of nonradiolabeled drugs in the brain ex vivo. This new method fuses the concepts of standard competition and saturation binding assays and uses a transformed version of the Cheng-Prusoff equation (Biochem Pharmacol 22:3099-3108, 1973) to calculate the drug concentration. After testing the validity of this method, we demonstrated its utility by measuring the brain concentration of sazetidine-A, a newly developed nicotinic receptor ligand, and its elimination rate after a single subcutaneous administration. Our results indicate that sazetidine-A reaches brain concentrations that are known to occupy and desensitize the majority of neuronal nicotinic acetylcholine receptor binding sites. Furthermore, using this method, we estimated the half-life of sazetidine-A in the rat brain to be ∼65 min. It is important to note that the method described here to measure sazetidine-A in brain should be generalizable to other drugs acting at any receptor that can be reliably measured with a radiolabeled ligand.


Assuntos
Encéfalo/metabolismo , Preparações Farmacêuticas/metabolismo , Ensaio Radioligante/métodos , Algoritmos , Animais , Azetidinas/análise , Azetidinas/farmacocinética , Sítios de Ligação , Ligação Competitiva/efeitos dos fármacos , Compostos Bicíclicos Heterocíclicos com Pontes/farmacocinética , Córtex Cerebral/metabolismo , Masculino , Agonistas Nicotínicos/análise , Agonistas Nicotínicos/farmacocinética , Preparações Farmacêuticas/análise , Piridinas/análise , Piridinas/farmacocinética , Ratos , Receptores Nicotínicos/metabolismo
15.
Addiction ; 107(10): 1857-67, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22594651

RESUMO

AIM: To determine the combined effect of very low nicotine content (VLNC) cigarettes and usual Quitline care [nicotine replacement therapy (NRT) and behavioural support] on smoking abstinence, in smokers motivated to quit. DESIGN: Single-blind, parallel randomized trial. SETTING: New Zealand. PARTICIPANTS Smokers who called the Quitline for quitting support were randomized to either VLNC cigarettes to use whenever they had an urge to smoke for up to 6 weeks after their quit date, in combination with usual Quitline care (8 weeks of NRT patches and/or gum or lozenges, plus behavioural support) or to usual Quitline care alone. MEASUREMENTS: The primary outcome was 7-day point-prevalence smoking abstinence 6 months after quit day. Secondary outcomes included continuous abstinence, cigarette consumption, withdrawal, self-efficacy, alcohol use, serious adverse events and views on the use of the VLNC cigarettes at 3 and 6 weeks and 3 and 6 months. FINDINGS: A total of 1410 participants were randomized (705 in each arm), with a 24% loss to follow-up at 6 months. Participants in the intervention group were more likely to have quit smoking at 6 months compared to the usual care group [7-day point-prevalence abstinence 33 versus 28%, relative risk (RR) = 1.18, 95% confidence interval (CI): 1.01, 1.39, P = 0.037; continuous abstinence 23 versus 15%, RR = 1.50, 95% CI: 1.20, 1.87, P = 0.0003]. The median time to relapse in the intervention group was 2 months compared to 2 weeks in the usual care group (P < 0.0001). CONCLUSIONS: Addition of very low nicotine content cigarettes to standard Quitline smoking cessation support may help some smokers to become abstinent.


Assuntos
Terapia Comportamental/métodos , Nicotina/administração & dosagem , Agonistas Nicotínicos/administração & dosagem , Abandono do Hábito de Fumar/métodos , Produtos do Tabaco/análise , Dispositivos para o Abandono do Uso de Tabaco , Adulto , Terapia Combinada , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Nicotina/análise , Agonistas Nicotínicos/análise , Recidiva , Método Simples-Cego , Abandono do Hábito de Fumar/estatística & dados numéricos , Resultado do Tratamento , Adulto Jovem
16.
Drug Alcohol Depend ; 125(1-2): 49-59, 2012 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-22498344

RESUMO

BACKGROUND: Nicotine is known to generate oxidative stress through cytochrome P450 2A6 (CYP2A6)-mediated metabolism in the liver and other organs, including macrophages. This study has been designed to examine the role of CYP2A6 in nicotine metabolism and oxidative stress in SVGA cells, an immortalized human astrocyte cell line. METHODS: SVGA astrocytes were treated with 1 µM nicotine, followed by determination of mRNA and protein levels of several CYPs using quantitative RT-PCR and western blot analyses, respectively. Quantitation of nicotine and the nicotine metabolites, cotinine and nicotine-derived nitrosamine ketones (NNK), was performed using an LC-MS/MS method. The generation of reactive oxygen species (ROS) was measured using flow cytometry. RESULTS: Nicotine significantly upregulated mRNA and protein expression of the most abundantly expressed CYPs in SVGA astrocytes, CYP2A6 and CYP1A1. To characterize the metabolism of nicotine in astrocytes, a highly sensitive LC-MS/MS method was developed which is capable of quantifying very low concentrations of nicotine (0.3 ng/mL), cotinine and NNK (0.11 ng/mL). The LC-MS/MS results showed that nicotine is steadily metabolized to cotinine and NNK from 0.5 to 4h. Finally, we showed that nicotine initially causes an increase in ROS formation which is then gradually decreased, perhaps due to the increase in superoxide dismutase level. Nicotine metabolism and ROS formation by CYP2A6 were further confirmed by using tryptamine, a selective inhibitor of CYP2A6, which significantly lowered the levels of cotinine and NNK and inhibited ROS formation. CONCLUSIONS: CYP2A6 plays a key role in nicotine metabolism and oxidative stress in astrocytes, and this has implications in nicotine-associated brain toxicity.


Assuntos
Hidrocarboneto de Aril Hidroxilases/metabolismo , Astrócitos/metabolismo , Nicotina/análogos & derivados , Nicotina/análise , Agonistas Nicotínicos/análise , Estresse Oxidativo/fisiologia , Hidrocarboneto de Aril Hidroxilases/biossíntese , Astrócitos/química , Astrócitos/enzimologia , Western Blotting , Linhagem Celular , Cromatografia Líquida de Alta Pressão , Cotinina/análise , Citocromo P-450 CYP1A1/biossíntese , Citocromo P-450 CYP1A1/metabolismo , Citocromo P-450 CYP2A6 , Indução Enzimática/efeitos dos fármacos , Humanos , Cetonas/análise , Limite de Detecção , Nicotina/farmacologia , Agonistas Nicotínicos/farmacologia , Nitrosaminas/análise , RNA/genética , RNA/isolamento & purificação , Espécies Reativas de Oxigênio/análise , Reação em Cadeia da Polimerase em Tempo Real , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem
17.
Bull Environ Contam Toxicol ; 88(6): 885-90, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22398693

RESUMO

A modified QuEChERS and LC-MS/MS method has been developed for the simultaneous determination of residues of six neonicotinoids in various crops, including spinach, cucumber, apple and pomelo. The method showed good linearity (R(2) ≥ 0.9995) and precision (RSD ≤ 14.0%). Average recoveries of the six neonicotinoids ranged between 73.7% and 103.8% at spiking levels 0.005, 0.1 and 1 mg kg(-1). The LODs and LOQs were in the ranges of 0.20-0.85 µg kg(-1) and 0.66-2.84 µg kg(-1), respectively. The method was satisfactorily validated for the analysis of 50 agricultural samples. Imidacloprid and imidaclothiz were detected at concentration levels ranging from 7 to 5.3 µg kg(-1).


Assuntos
Citrus/química , Cucumis sativus/química , Inseticidas/análise , Malus/química , Spinacia oleracea/química , Cromatografia Líquida , Contaminação de Alimentos/análise , Inseticidas/química , Agonistas Nicotínicos/análise , Agonistas Nicotínicos/química , Resíduos de Praguicidas/análise , Receptores Nicotínicos/metabolismo , Medição de Risco , Espectrometria de Massas em Tandem
18.
J Biomol Screen ; 16(8): 917-24, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21799121

RESUMO

This study describes the evaluation, validation, and use of contactless postcolumn fractionation of bioactive mixtures with acetylcholine binding protein (AChBP) affinity analysis with help of a spotter technology. The high-resolution fractionation tailors the fractionation frequency to the chromatographic peaks. Postcolumn reagents for AChBP bioaffinity profiling are mixed prior to droplet ejection into 1536-well plates. After an incubation step, microplate reader analysis is used to determine bioactive compounds in a mixture. For ligands tested, a good correlation was found for IC(50)s determined in flow injection analysis mode when compared with traditional radioligand binding assays. After the evaluation and validation, bioaffinity profiling of actual mixtures was performed. The advantage of this "atline" technology using postcolumn bioaffinity analysis when compared to continuous flow online postcolumn bioaffinity profiling is the possibility to choose postcolumn incubation times freely without compromising resolution due to diffusion effects.


Assuntos
Proteínas de Transporte , Cromatografia de Afinidade/métodos , Cromatografia Líquida de Alta Pressão/métodos , Misturas Complexas/análise , Análise de Injeção de Fluxo/métodos , Ensaios de Triagem em Larga Escala , Compostos Bicíclicos Heterocíclicos com Pontes/análise , Compostos Bicíclicos Heterocíclicos com Pontes/metabolismo , Proteínas de Transporte/química , Proteínas de Transporte/metabolismo , Fracionamento Químico/métodos , Cromatografia de Afinidade/instrumentação , Misturas Complexas/química , Análise de Injeção de Fluxo/instrumentação , Ligantes , Espectrometria de Massas/métodos , Nanotecnologia/métodos , Nicotina/análise , Nicotina/metabolismo , Agonistas Nicotínicos/análise , Agonistas Nicotínicos/metabolismo , Ligação Proteica , Piridinas/análise , Piridinas/metabolismo , Ensaio Radioligante , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Reprodutibilidade dos Testes
19.
J Anal Toxicol ; 34(7): 357-66, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20822672

RESUMO

The objective of this preliminary study was to identify and quantify potential nicotine (NIC) biomarkers in post-exposure oral fluid samples collected from 10 NIC-abstinent human participants administered 7 mg transdermal NIC using liquid chromatography-tandem mass spectrometry (LC-MS-MS). Oral fluid samples were collected prior to NIC patch application and at 0.5 and 0.75 h after patch removal using the Quantisal() oral fluid collection device. The validated LC-MS-MS analyte panel included nicotine-Nbeta-D-glucuronide, cotinine-N-oxide, trans-3-hydroxycotinine, norcotinine, trans-nicotine-1'-N-oxide, cotinine (COT), nornicotine, NIC, anatabine, anabasine, and cotinine-N-beta-D-glucuronide. Analytes and corresponding deuterated internal standards were extracted by solid-phase extraction. NIC and COT concentrations were quantifiable in oral fluid samples collected from 6 of the 10 participants 0.5 h after patch removal and in oral fluid samples collected from 7 of the 10 participants 0.75 h after patch removal. Based on the mean NIC and COT concentrations in oral fluid and plasma for the participants with both quantifiable NIC and COT at the 0.5 and 0.75 h collection times, the oral fluid-plasma ratio was 6.4 for NIC and 3.3 for COT. An ELISA procedure was also validated and successfully applied as a screening tool for these oral fluid samples in conjunction with LC-MS-MS confirmation. An ELISA cut-off concentration of 5.0 ng/mL provided excellent sensitivity for discrimination of COT-positive post-exposure oral fluid samples collected after low-level transdermal NIC exposure and oral fluid samples collected prior to patch application.


Assuntos
Cotinina/análise , Nicotina/análise , Agonistas Nicotínicos/análise , Saliva/química , Detecção do Abuso de Substâncias/métodos , Administração Cutânea , Biomarcadores/análise , Cromatografia Líquida , Ensaio de Imunoadsorção Enzimática , Humanos , Nicotina/administração & dosagem , Agonistas Nicotínicos/administração & dosagem , Reprodutibilidade dos Testes , Extração em Fase Sólida , Espectrometria de Massas em Tandem
20.
Hum Psychopharmacol ; 25(7-8): 577-81, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21312293

RESUMO

OBJECTIVE: A growing body of evidence suggests that non-pharmacological factors may play an important role in smoking cessation outcomes using nicotine replacement therapies. This study examined the role of information about nicotine content in smokers' subjective responses to nicotine and placebo inhalers, using the four conditions of the balanced-placebo design in a mixed within/between-subjects design. METHODS: Twenty-four adult smokers (12 male) completed two laboratory sessions following overnight abstinence from smoking. Participants were randomly assigned to receive either nicotine inhalers or placebo inhalers in both sessions but were told that they received a nicotine-containing inhaler in one session and a nicotine-free inhaler in the other. In each session participants completed subjective assessments before and after inhaler administration using visual analogue scales and the Brief Questionnaire of Smoking Urges. RESULTS: While neither nicotine content nor information about it significantly affected cigarette craving associated with withdrawal relief, participants reported a greater reduction in craving associated with intention to smoke when told the inhalers contained nicotine than when told the inhalers were nicotine-free, regardless of actual nicotine content. CONCLUSIONS: Findings suggest that psychological factors play an important role in smokers' subjective responses to nicotine inhalers, the effects of which cannot be solely attributed to the direct pharmacological effects of nicotine.


Assuntos
Nicotina/farmacologia , Agonistas Nicotínicos/farmacologia , Fumar/psicologia , Adulto , Afeto/efeitos dos fármacos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Nebulizadores e Vaporizadores , Nicotina/administração & dosagem , Nicotina/análise , Agonistas Nicotínicos/administração & dosagem , Agonistas Nicotínicos/análise , Placebos , Psicometria , Nicotiana , Resultado do Tratamento , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...