Effects of cessation of cigarette smoking on eicosanoid biomarkers of inflammation and oxidative damage.

The urinary metabolites "prostaglandin E2 metabolite" (PGE-M) and (Z)-7-[1R,2R,3R,5S)-3,5-dihydroxy-2-[(E,3S)-3-hydroxyoct-1-enyl]cyclopentyl]hept-5-enoic acid (8-iso-PGF2α) are biomarkers of inflammation and oxidative damage, respectively, and are elevated in cigarette smokers. Relatively little is known about the effects of smoking cessation on these biomarkers. To investigate this, current cigarette smokers interested in quitting were recruited and invited to participate in a smoking cessation study where varenicline (Chantix) and brief supportive behavioral counseling were offered at each visit after baseline. Subjects returned to the clinic during the 12 week treatment phase for 9 visits post cessation on days 3, 7, 14, 21, 28, 42, 56, 70 and 84. Urine samples were collected at each visit and analyzed by liquid chromatography-tandem mass spectrometry for PGE-M, 8-iso-PGF2α, and cotinine. Cotinine values demonstrated that 15 of 38 subjects quit smoking for the entire 84 day period. Significant decreases in mean levels of PGE-M and 8-iso-PGF2α per milligram creatinine were observed in these subjects, by 44% (p = 0.0014) and 27% (p<0.001), respectively. The results of this study demonstrate that cessation of smoking for 84 days results in modest but significant declines in urinary PGE-M and 8-iso-PGF2α indicating reductions in systemic inflammation and oxidative damage. Given that levels were only modestly decreased, these markers are not specific to tobacco-smoke exposure. The modest declines in these biomarkers should be considered when planning studies with ex-smokers. There is a "hangover" from smoking that lasts at least 3 months

Effects of immediate versus gradual nicotine reduction in cigarettes on biomarkers of biological effects.

AimA previous study showed significantly greater reductions in number of cigarettes smoked and biomarkers of toxicant and carcinogen exposure in smokers assigned to immediate reduction of nicotine in cigarettes to very low levels versus gradually over time or continued smoking of normal nicotine content cigarettes. This study examines the effects of these approaches on selected biomarkers associated with harmful biological effects.DesignThree-arm, randomized controlled trial.SettingTen United States academic institutional sites.ParticipantsDaily smokers uninterested in quitting smoking with a mean age of 45.1 [standard deviation (SD)&nbsp;=&nbsp;13.4)] years and smoking 17.1 (SD&nbsp;=&nbsp;8.5) cigarettes/day; 43.9% (549 of 1250) female; 60.6% (758 of 1250) white ethnicity.Interventions(1) Smoking cigarettes where nicotine content was immediately reduced to very low levels (n&nbsp;=&nbsp;503); (2) smoking cigarettes where nicotine content was gradually reduced, with dose changes occurring monthly (n&nbsp;=&nbsp;498); and (3) continued smoking with normal nicotine content cigarettes (n&nbsp;=&nbsp;249).MeasurementsSmokers were assessed at baseline while smoking their usual brand cigarettes, and again at 4, 8, 12, 16 and 20&nbsp;weeks. Outcomes were areas under the concentration time curve (AUC) for the period of study of biomarkers of inflammation, oxidative stress and hematological parameters.FindingsNo consistent significant differences were observed across groups (Bayes factors showing data to be insensitive), with the only exception being red blood cell size variability, which was observed to be lower in the immediate versus gradual nicotine reduction [mean difference&nbsp;=&nbsp;&nbsp;-0.11; 95% confidence interval (CI)&nbsp;=&nbsp;-0.18, -0.04, P&nbsp;=&nbsp;0.004] and normal nicotine control groups (mean difference&nbsp;=&nbsp;-&nbsp;0.15, 95% CI&nbsp;=&nbsp;-0.23, -0.06, P&nbsp;=&nbsp;0.001).ConclusionIt remains unclear whether switching to very low nicotine cigarettes leads to a short-term reduction in biomarkers of tobacco-related harm

Effects of immediate versus gradual nicotine reduction in cigarettes on biomarkers of biological effects.

AimA previous study showed significantly greater reductions in number of cigarettes smoked and biomarkers of toxicant and carcinogen exposure in smokers assigned to immediate reduction of nicotine in cigarettes to very low levels versus gradually over time or continued smoking of normal nicotine content cigarettes. This study examines the effects of these approaches on selected biomarkers associated with harmful biological effects.DesignThree-arm, randomized controlled trial.SettingTen United States academic institutional sites.ParticipantsDaily smokers uninterested in quitting smoking with a mean age of 45.1 [standard deviation (SD)&nbsp;=&nbsp;13.4)] years and smoking 17.1 (SD&nbsp;=&nbsp;8.5) cigarettes/day; 43.9% (549 of 1250) female; 60.6% (758 of 1250) white ethnicity.Interventions(1) Smoking cigarettes where nicotine content was immediately reduced to very low levels (n&nbsp;=&nbsp;503); (2) smoking cigarettes where nicotine content was gradually reduced, with dose changes occurring monthly (n&nbsp;=&nbsp;498); and (3) continued smoking with normal nicotine content cigarettes (n&nbsp;=&nbsp;249).MeasurementsSmokers were assessed at baseline while smoking their usual brand cigarettes, and again at 4, 8, 12, 16 and 20&nbsp;weeks. Outcomes were areas under the concentration time curve (AUC) for the period of study of biomarkers of inflammation, oxidative stress and hematological parameters.FindingsNo consistent significant differences were observed across groups (Bayes factors showing data to be insensitive), with the only exception being red blood cell size variability, which was observed to be lower in the immediate versus gradual nicotine reduction [mean difference&nbsp;=&nbsp;&nbsp;-0.11; 95% confidence interval (CI)&nbsp;=&nbsp;-0.18, -0.04, P&nbsp;=&nbsp;0.004] and normal nicotine control groups (mean difference&nbsp;=&nbsp;-&nbsp;0.15, 95% CI&nbsp;=&nbsp;-0.23, -0.06, P&nbsp;=&nbsp;0.001).ConclusionIt remains unclear whether switching to very low nicotine cigarettes leads to a short-term reduction in biomarkers of tobacco-related harm

Ritmos de reconhecimento do litoral chinês na cartografia histórica portuguesa (século XVI)

UID/HIS/04666/2013Este artigo pretende proporcionar uma leitura de conjunto sobre os litorais chineses conforme representados na cartogra a portuguesa de base náutica durante o século XVI.publishersversionpublishe