声光可调-NIR法预测烟草中的总烟碱、总糖、还原糖和总氮

采用声光可调(AOTF)-近红外光谱(NIR)仪和Unscrambler化学计量学光谱分析软件,通过旋转扫描的方式测定了534个不同年份、不同地区、不同等级国产烤烟烟叶样品的NIR,采用PLS1建立了测定烟草中总烟碱、总糖、还原糖和总氮的校正模型,并用这些模型对41个未知烤烟烟叶样品进行了预测。结果表明:总烟碱、总糖、还原糖和总氮含量的NIR预测模型的决定系数R2分别为0.9869、0.9851、0.9733和0.9721,预测的平均相对偏差分别为4.21%、2.23%、2.91%和3.60%。AOTF-NIR技术适用于烟草中总烟碱、总糖、还原糖和总氮含量的快速分析。     

尼古丁对药物性胃溃疡影响的实验研究

目的 探讨尼古丁对小鼠药物性胃溃疡的影响.方法 随机将昆明种小鼠分为5组:生理盐水对照组及0.25,0.5,1.0,10 mg/kg尼古丁实验组.消炎痛灌胃制成小鼠胃溃疡模型,造模前和造模后用尼古丁灌胃,计算溃疡指数.结果 尼古丁组胃溃疡指数明显低于生理盐水对照组.结论 在一定剂量范围内,尼古丁能预防药物性胃溃疡生成,...     

烟碱脱氢酶基因的原核表达及酶学特性研究

将含烟碱脱氢酶基因重组质粒pBlueScript SK-ndh用限制性内切酶EcoRI、SpeI双酶切,目的基因再亚克隆到非融合表达质粒载体pET-17B,获得重组子质粒pET-17B-ndh,转化大肠杆菌BL21(DE3)pLYS获得高酶活力表达的工程菌株。即使在不用IPTG诱导情况下,该工程菌也产生较高酶活力的可溶性酶,酶产量比野生菌A. nicotinovorans提高25倍。通过硫酸铵沉淀、离子交换层析、凝胶过滤提纯了烟碱脱氢酶,酶被纯化了39.82倍,SDS-PAGE分析得到电泳纯单一条带。该酶活力的最适温度为40℃,该酶组分在pH5.5~8.0范围内稳定,最适pH7.0,对烟碱作用的Km值为7.694×10-4mol/L。Mn2+、Co2+是酶的激活剂,Cu2+是酶的抑制剂。烟碱降解条件研究表明在反应体系中需要辅酶或电子接受体参与介导质子(H+)的转移,该酶催化反应是一种氧化还原反应体系。      

索氏抽提法萃取活性炭滤嘴中吸附的烟碱

研究了采用索式抽提法萃取活性炭滤嘴中吸附的烟碱,包括萃取剂酸碱性的影响、抽提的条件以及方法的精密度和准确度。结果表明：①甲醇的酸碱性对醋酸纤维滤嘴中烟碱的萃取效果无明显影响,酸性甲醇溶液对活性炭滤嘴中的烟碱萃取效果较好;②振荡提取对活性炭滤嘴中吸附的烟碱量萃取不完全;③索式抽提法对萃取活性炭滤嘴中吸附的烟碱效果较好,回收率大于98%;④采用索式提取-气相色谱法测定活性炭滤嘴中的烟碱,重复性变异系数小于4%。     

Wound-induced changes in root and shoot jasmonic acid pools correlate with induced nicotine synthesis inNicotiana sylvestris spegazzini and comes

Leaf damage by herbivores inNicotiana sylvestris Spegazzini and Comes (Solanaceae) produces a damage signal that dramatically increasesde novo nicotine synthesis in the roots. The increased synthesis leads to increases in whole-plant nicotine pools, which in turn make plants more resistant to further herbivore attack. Because signal production and the response to the signal occur in widely separated tissues, the speed with which different damage signals exit a damaged leaf can be studied. We propose that electrical damage signals should exit a leaf faster (less than 60 min) than chemical damage signals. Excision of a leaf induces a smaller increase in nicotine production than does puncture damage, so we examined our proposition by excising previously punctured leaves at 1, 60, and 960 min after leaf puncture and quantifying the induced whole-plant nicotine pools six days later when the induced nicotine production had reached a maximum. Significant induced nicotine production occurred only if punctured leaves were excised more than 1 hr after puncture, which is consistent with the characteristics of a slow-moving chemical signal rather than a fast-moving electrical signal. We explore the nature of the chemical signal and demonstrate that additions of 90µg or more of methyl jasmonate (MJ) in an aqueous solution to the roots of hydroponically grown plants inducede novo nicotine synthesis from¹⁵NO₃ in a manner similar to that induced by leaf damage. We examine the hypothesis that jasmonic acid (JA) functions in the transfer of the damage signal from shoot to root. Using GC-MS techniques to quantify whole-plant JA pools, we demonstrate that leaf damage rapidly (<0.5 hr) increases shoot JA pools and, more slowly (<2 hr), root JA pools. JA levels subsequently decay to levels found in undamaged plants within 24 hr and 10 hr for shoots and roots, respectively. The addition of sufficient quantities (186µg) of MJ in a lanolin paste to leaves from hydroponically grown plants significantly increased endogenous root JA pools and increasedde novo nicotine synthesis in these plants. However, the addition of 93µg or less of MJ did not significantly increase endogenous root JA pools and did not significantly affectde novo nicotine synthesis. We propose that wounding increases shoot JA pools, which either directly through transport or indirectly through a systemin-like signal increase root JA pools, which, in turn, stimulate root nicotine synthesis and increase whole-plant nicotine pools.     

第三代烟碱类杀虫剂呋虫胺的合成

叙述了第三代烟碱类杀虫剂呋虫胺的5种合成方法。采用"(四氢-3-呋喃)-甲基对甲苯磺酸酯"的合成方法进行了试验。(四氢-3-呋喃)甲醇用对甲苯磺酰氯酯化,甲基硝基胍用甲醛、甲胺环化,1,5-二甲基-2-硝基亚胺六氢-1,3,5-三嗪和3-四氢呋喃甲基对甲苯磺酸酯缩合,分解制得呋虫胺。总收率60.5%(以甲基硝基胍计),含量98%。该法最易工业化。     

The relationship between in-treatment abstinence and post-treatment abstinence in a smoking cessation treatment.

Previous research has indicated that abstinence early in a smoking cessation program is predictive of successful posttreatment abstinence. However, it has not been established whether or not this effect is independent of other in-treatment abstinence patterns. In this paper the relationship between three potentially important aspects of in-treatment smoking abstinence and posttreatment smoking abstinence are examined: early abstinence, extended abstinence, and end-of-treatment abstinence. We examined the relationship between smoking behavior measured each weekday over 70 visits (approximately 14 weeks) of a contingency management smoking cessation program and at a follow-up visit 6 months after study entry (3 months after the scheduled end of treatment). Ninety-five of 102 participants were successfully followed-up. Seven of these 95 participants were confirmed abstinent. Early abstinence, defined as abstinence during the first 10 treatment visits, was significantly and independently related to follow-up abstinence (OR = 56.67 [7.29–440.63]). Extended abstinence and end-of-treatment abstinence were related to follow-up abstinence, but not independent of early abstinence based on multiple regression models. Inclusion of a variety of demographic and environmental characteristics did not significantly alter this relationship. Thus, consistent with the previous literature, the establishment of early abstinence appears to be crucial to establishing longer-term abstinence, independent of other in-treatment abstinence patterns. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Brain fMRI reactivity to smoking-related images before and during extended smoking abstinence.

[Correction Notice: An erratum for this article was reported in Vol 18(3) of Experimental and Clinical Psychopharmacology (see record 2010-11933-011). In the article the authors find it necessary to redefine the thresholding procedure used for data analyses, due to problems in the Brain Voyager software. This does not affect the main findings of the paper.] Reactivity to smoking-related cues may play a role in the maintenance of smoking behavior and may change depending on smoking status. Whether smoking cue-related functional MRI (fMRI) reactivity differs between active smoking and extended smoking abstinence states currently is unknown. We used fMRI to measure brain reactivity in response to smoking-related versus neutral images in 13 tobacco-dependent subjects before a smoking cessation attempt and again during extended smoking abstinence (52 ± 11 days) aided by nicotine replacement therapy. Prequit smoking cue induced fMRI activity patterns paralleled those reported in prior smoking cue reactivity fMRI studies. Greater fMRI activity was detected during extended smoking abstinence than during the prequit assessment subcortically in the caudate nucleus and cortically in prefrontal (BA 6, 9, 44, 46), primary somatosensory (BA 1, 2, 3), temporal (BA 22, 41, 42), parietal (BA 7, 40) anterior cingulate (BA 24, 32), and posterior cingulate (BA 31) cortex. These data suggest that during extended smoking abstinence, fMRI reactivity to smoking versus neutral stimuli persists in brain areas involved in attention, somatosensory processing, motor planning, and conditioned cue responding. In some brain regions, fMRI smoking cue reactivity is increased during extended smoking abstinence in comparison to the prequit state, which may contribute to persisting relapse vulnerability. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Subjective responses to intravenous nicotine: Greater sensitivity in women than in men.

Although approximately 45% of smokers in the United States are women, the influence of sex on nicotine dependence remains incompletely understood. Evidence from preclinical and clinical studies has indicated that there are significant sex differences in nicotine's effects. The authors' goal in this report was to determine whether men and women differ in their acute response to intravenous nicotine, which has not been examined in previous studies. Twelve male and 12 female smokers received saline followed by 0.5 mg/70 kg and 1.0 mg /70 kg nicotine intravenously. In response to nicotine, women, as compared with men, had enhanced ratings for drug strength, head rush, and bad effects. Women and men experienced similar suppression of smoking urges by nicotine as assessed by the Brief Questionnaire on Smoking Urges. Nicotine-induced heart rate and systolic and diastolic blood pressure increases were also similar in magnitude in men and women. The findings, consistent with those of several previous studies, support greater sensitivity of female smokers to some but not all of the subjective effects of nicotine. Further studies are warranted to examine the role of this differential nicotine sensitivity to development of nicotine dependence and response to nicotine replacement treatments in men and women. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nicotine dependence subtypes among adolescent smokers: Examining the occurrence, development and validity of distinct symptom profiles.

To increase understanding of the etiology and epidemiology of nicotine dependence among adolescent smokers, the present study examined the occurrence and development of distinct nicotine dependence symptom profiles in a sample of adolescent smokers. A total of 25 secondary schools throughout the Netherlands participated in a 1-year longitudinal study. Multiple dimensions of nicotine dependence were assessed, at two time points, among 641 adolescents (aged 14–17 years) who were classified as smokers. Results showed 4 distinct, yet stable, nicotine dependence subtypes that could be characterized by quantitative as well as qualitative differences. The symptom profiles were similar for males and females but differentially associated with previously identified correlates of nicotine dependence, namely parental smoking, peer smoking, and depressive mood. Finally, differential links of the 4 subtypes were found with regard to smoking uptake and cessation. The finding of qualitative different subgroups of adolescent smokers may have important implications for intervention efforts regarding nicotine dependence and smoking cessation. Such efforts may need to be tailored to the specific subgroups’ needs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)