海洛因滥用者尿液过氧化脂质含量的探讨

检测３８例海洛因滥用者和４０例健康对照者尿液过氧化脂质（Ｕ—ＬＰＯ）含量的结果表明，海洛因滥用者组的Ｕ－ＬＰＯ平均含量显著高于健康对照组（Ｐ＜０．００１），海洛因滥用者的Ｕ－ＬＰＯ含量随其尿液吗啡含量及滥用海洛因时间的增加而升高，并均呈线性正相关（ｒ＝０．７８５５，Ｐ＜０．００１：ｒ＝０．６６７４．Ｐ＜０．００１），提示海洛因滥用者体内的脂质过氧化反应呈现病理性加剧。     

香烟依赖与血浆维生素C、E浓度的关系

检测配对设计的５７例吸烟者和５７例健康非吸烟者血浆维生素Ｃ（Ｐ－ＶＣ）和血浆维生素Ｅ（Ｐ－ＶＥ）浓度的结果表明，吸烟组的Ｐ－ＶＣ和Ｐ－ＶＥ平均浓度显著低于健康非吸烟组之值（Ｐ＜０．００１），吸烟者的Ｐ－ＶＣ和Ｐ－ＶＥ浓度均随吸烟史的增加而降低（ｒ＝－０．５７８７，Ｐ＜０．０００１；ｒ＝－０．５３１０，Ｐ＜０．０００１），也均随吸烟量的增加而降低（ｒ＝－０．５８９９，Ｐ＜０．０００１；ｒ＝－０．５４６６，Ｐ＜０．０００１），吸烟者的Ｐ－ＶＥ浓度随Ｐ－ＶＣ浓度的下降而降低（ｒ＝０．８４２７，Ｐ＜０．０００１）；提示吸烟者体内的抗氧化剂水平显著降低，氧化和抗氧化平衡严重失调。     

海洛因滥用者尿泫过氧化脂质含量的探讨

检测３８例海洛因滥用者和４０例健康对照者尿液过氧化脂质（Ｕ－ＬＰＯ）含量的结果表明，海洛因滥用者组的Ｕ－ＬＰＯ平均含量显著高于健康对照组（Ｐ〈０．００１），海洛因滥用的Ｕ－ＬＰＯ含量随其尿液吗啡含量及滥用海洛因时间的增加而升高，并均呈线性正相关（ｒ＝０．７８５５，ｐ〈０．００１；ｒ＝０．６６７４，ｐ〈０．００１），提示海洛因滥用者体内的脂质过氧化反应呈现病理性加剧。     

肾脏病患者血浆过氧化脂质含量和血清超氧化物歧化酶含量的观察

测定了５７例肾脏疾病和４７例正常人的血浆过氧化脂质和血清超氧化歧化酶（ＳＯＤ）含量，结果显示慢性肾盂肾炎患者血浆ＬＰＯ均值显著高于正常（Ｐ〈０．０５），而血清ＳＯＤ显著低正常（Ｐ〉０．０５）；肾病综合征Ⅱ型的ＬＰＯ均显著高于正常（Ｐ〈０．００１），肾病综合征Ⅰ型的ＬＰＯ与正常人相比无显著性差异（Ｐ〉０．０５）；肾病综合Ⅰ型和Ⅱ型患者血清ＳＯＤ与正常人相比无显著性差异（Ｐ〈０．０５）；慢性肾功能不全     

纳络酮对缺血再灌注心肌脂质过氧化物和钙含量的影响

利用大心肌缺血、再灌注模型，观察了纳络酮对缺血再藻注心肌脂质过氧化物（ＬＰＯ）、超氧化物歧化酶（ＳＯＤ）和钙含量的影响。结果表明：缺血、再灌注心肌ＬＰＯ和钙含量明显增加（Ｐ＜０．０５，Ｐ＜０．０１），再灌注心肌ＬＰＯ含量和钙含量明显高于缺血心肌（Ｐ＜０．０５，Ｐ＜０．０１），而缺血、再灌注心肌ＳＯＤ明显降低（Ｐ＜０．０１）；纳络用明显降低缺血、再灌注心肌ＬＰＯ和钙含量（Ｐ＜０．０５，Ｐ＜００１），但对ＳＯＤ的影响不明显（Ｐ＞０．０５）。提示：纳络酮抑制心肌缺血、再灌注时的脂质过氧化物反应，部份阻止细胞外钙跨膜内流，对心肌只响保护作用。     

三七总皂苷对冠心病患者过氧化脂质及纤维蛋白溶酶原激活物的影响

目的：观察三七总皂苷对冠心病患者血清超氧化物歧化酶（ＳＯＤ）、过氧化脂质（ＬＰＯ）、组织型纤维蛋白溶酶原激活物（ｔＰＡ）及组织型纤维蛋白溶酶原激活物抑制剂（ＰＡＩ－１）的影响。方法：将４５例患者分成２组,三七总皂苷治疗组用三七总皂苷注射液５００ｍｇ加入２５０ｍｌ液体中静滴,ｑｄ,共１周,余治疗同对照组。结果：治疗组血清ＳＯＤ活力明显增高（Ｐ〈０．０１）,ＬＰＯ含量降低（Ｐ〈０．０１）。对照组ＳＯＤ活力及ＬＰＯ含量用药前后无明显改变（Ｐ均〉０．０５）,血清ＳＯＤ的含量在治疗组用药前后和对照组皆无明显差别（Ｐ均〉０．０５）。三七总皂苷治疗后ｔＰＡ明显高于治疗组,ＰＡＩ－１明显低于治疗前（Ｐ均〈０．０１）。而对照组治疗前后无明显变化（Ｐ均〉０．０５）。结论：三七总皂苷能升高冠心病患者ＳＯＤ活力,降低ＬＰＯ含量,提高纤     

钙通道阻滞剂抗肝缺血—再灌注损伤作用机制的实验研究

目的 探讨钙通道阻滞剂（ＣＣＥＢ）对肝缺血一再灌注损伤（ＨＩＲＩ）防治作用的机制。方法制备家兔ＨＩＲＩ模型,动态观察维拉帕米（ＶＰ）和地尔硫卓（ＤＴ）对肝组织及血中黄嘌呤氧化酶（ＸＯ）、超氧化物歧化酶（ＳＯＤ）活性及脂质过氧化物（ＬＰＯ）浓度的影响。结果 ＶＰ组和ＤＴ组ＯＸ活性及ＭＤＡ含量分别显著低于对照组（均Ｐ＜０．０１）,而ＳＯＤ活性与对照组比较均无显著性差异（均 Ｐ＞ ０．０５）。结论 ＣＣＥＢ抗 ＨＩＲＩ的机制与其降低 ＸＯ活性、抑制脂质过氧化反应密切相关。     

海脉冲营养素抗衰老作用的实验研究

本文报道了海脉冲营养素对老龄大鼠体内过氧化脂质（ＬＰＯ）,脂褐素（ＬＰＦ）的含量和超氧化物歧化酶（ＳＯＤ）,光胱甘肽过氧化物酶（ＧＳＨ－Ｐｘ）活性的影响。给老龄大鼠灌服海脉冲营养６０ｄ,结果表明：血液及肝脏中ＬＰＯ含量明显降低（Ｐ〈０．０５）;ＳＯＤ和ＧＳＨ－Ｐｘ酶活性显著提高（Ｐ〈０．０５）;大脑皮层中ＬＰＦ的生成明显减少（Ｐ〈０．０１）。提示海脉冲营养素具有提高老龄大鼠体内抗氧化酶活性、清除自由基、抑制脂质过氧化的作用。     

硒多糖、亚砷酸钠对大鼠肝微粒体酶和GSH-Px等的影响

研究了硒多糖、亚砷酸钠在体内、外对大鼠肝微粒体酶细胞色素Ｐ－４５０、ｂ５、ＮＡＤ（Ｐ）Ｈ－细胞色素Ｃ还原酶、谷胱甘肽硫转移酶（ＧＳＴ）的影响;并通过测定硒多糖、亚砷酸钠对肝谷胱甘肽过氧化物酶（ＧＳＨ－Ｐｘ）和脂质过氧化（ＬＰＯ）的影响,探讨了硒、砷相互作用的机理。结果表明：连续７天腹腔注射０．２ｍｇ／ｋｇ硒多糖,细胞色素Ｐ－４５０、ｂ５的含量、ＧＳＴ的活性降低（Ｐ＜０．０５）;硒多糖明显诱导ＧＳＨ－Ｐｘ的活性,降低脂质过氧化,拮抗亚砷酸钠对ＬＰＯ的作用。亚砷酸钠显著增强肝细胞脂质过氧化（Ｐ＜０．０５）,对ＧＳＨ－Ｐｘ和肝微粒体酶无明显影响     

银杏叶制剂对心绞痛患者的抗氧化和抗脂质过氧化作用

目的：探讨银杏叶制剂对心绞痛患者的抗氧化和抗脂质过氧化作用。方法：检测了７８例心绞痛患者经银杏叶制剂“天宝宁”治疗前后的血浆维生素Ｃ（Ｐ－ＶＣ）、维生素Ｅ（Ｐ－ＶＥ）、β－胡萝卜素（Ｐ－β－ＣＡＲ）、过氧化脂质（Ｐ－ＬＰＯ）以及红细胞超氧化物歧化酶（Ｅ－ＳＯＤ）、过氧化氢酶（Ｅ－ＣＡＴ）、谷胱甘肽过氧化物酶（Ｅ－ＧＳＨ－ＰＸ）、过氧化脂质（Ｅ－ＬＰＯ）值。结果：与治疗前比较,治疗后的Ｐ－ＶＣ、Ｐ－     

Individual change amid stable smoking patterns in polydrug users over 3 years

The pattern of stability/change in smoking status was examined annually in 254 community-dwelling polydrug users over 3 years. Respondents' smoking status was classified as nonsmoker, intermittent smoker, or "everyday" smoker. Results showed that the typical probability of retaining the same smoking status across any two consecutive assessments was: 0.77 for nonsmokers (never smokers and former smokers combined), 0.82 for everyday smokers, and 0.16 for intermittent smokers. The transition matrix proved stable across three observations; the predicted equilibrium distribution matched well with observed distributions. Fifty-five percent of intermittent smokers converted to everyday smoking within a year, but 29% converted to former-smoker status in the same period. No other transition exceeded 12%. Considerable flux in individual smoking status, particularly among intermittent smokers, was observed despite stable prevalence of smoking status in this population. Intermittent smoking status appeared to be a temporary "way station" between the two more stable everyday smoker and nonsmoker classifications. Results challenge current assumptions about "occasional" or "chipper" smokers.     

Hypothesis for temporal displacement of metabolic and neuronal accommodation in smoking addiction

Using the overlapping criteria of (1) current smoking status and (2) homeostatic accommodation of smoking, the categories of nonsmoker, beginning smoker, smoker, and quitting smoker are structured into a cyclic representation of smoking addiction. This cyclic representation reveals that elimination of homeostatic accommodation of smoking is a critical success factor to the process of becoming a nonsmoker, while the act of stopping smoking is necessary yet insufficient to the success of that process. Homeostatic accommodation is described as having two components: metabolic and neuronal. A hypothesis for temporal displacement of metabolic and neuronal accommodation is presented to explain the behavior of "chippers" (occasional smokers) and adolescent smokers. Recommendations are made for research on the rates of development and dissipation of metabolic and neuronal accommodation of smoking, and for the development of a bimodal therapy that addresses both metabolic and neuronal accommodation and reduces relapse for quitting smokers.     

The effect of cigarette burn time on exposure to nicotine and carbon monoxide in adult smokers

Cigarette burn time (CBT), conventionally defined as the time a cigarette burns during smoking, can be affected by cigarette design and smoking behavior. A previous study showed a strong negative correlation between CBT and nicotine yield under machine smoking conditions. This study for the first time examined the relationship of CBT and exposure to nicotine and carbon monoxide in adult smokers in a controlled clinical study. 24h nicotine equivalents excretion (NE), carboxyhemoglobin (COHb) and CBT were measured in two groups of 20 adults smoking Marlboro Lights and 20 adults smoking Marlboro Ultra on two consecutive days. Approximately 20% of the total variability in CBT was attributed to cigarette brand, 34% to smokers and 1% to study day. The exposure index, defined as the number of cigarettes smoked per day divided by average daily CBT for each smoker, accounted for a large proportion of the total variability in NE (R(2)=0.79-0.91) and COHb (R(2)=0.85-0.90). We conclude that CBT has an important influence on levels of NE and COHb in adult smokers. CBT, along with the number of cigarettes smoked per day, can be used to estimate adult smokers' exposure to nicotine and carbon monoxide.     

Behavioral and biochemical effects of gradual reductions in cigarette yields in pregnant and nonpregnant smokers

Smoking-related risks have been well-documented for both the smoker and the pregnant smoker's unborn child, but the risks associated with low tar/nicotine cigarette smoking are still controversial. The present study examined some of the behavioral and biochemical effects of gradual reductions in tar and nicotine yields in six pregnant and six nonpregnant smokers. Over four sessions spanning a 6-week period, smokers switched to cigarette brands progressively lower in tar and nicotine. Examination of the topographical variables assessed both during (cigarette frequency, puff frequency, and cigarette duration) and between sessions (daily cigarette rate and nicotine intake) revealed significant decreases in both pregnant and nonpregnant smokers' cigarette duration and nicotine intake. Also observed were significantly lower and less variable carboxyhemoglobin (COHb) levels among the pregnant smokers when they smoked the lowest tar and nicotine brands. However, even the pregnant smokers' lower mean COHb levels did not drop below the 3% minimal cardiovascular risk level. The pregnant smokers also tended to have lower and less variable salivary thiocyanate (SCN) levels, but these differences were nonsignificant. The results were discussed in terms of implications for controlled smoking treatment programs for pregnant smokers.     

Effects of cigarette smoking on phobic anxiety

Smokers report that smoking reduces anxiety. However, experimental research on the anxiety-reducing effects of smoking is limited to two self-report studies, both of which have methodological problems. We tested the effects of smoking on self-reported anxiety and avoidance behavior in a behavioral avoidance test (BAT) using a large white rat. In a counterbalanced within subjects design, 20 rat phobic female smokers smoked or were smoking deprived in two separate administrations of the BAT. A second group of 20 rat phobic nonsmokers also received two BATs. Subjects manifested substantial anxiety during BATs. However, neither smoking condition nor smoker versus nonsmoker status affected self-reported or motoric anxiety. Although smoking did not reduce anxiety in this study, smoking may affect anxiety in other situations, such as social settings, where the stimulus is more diffuse or less intense. It may also affect anxiety in individuals who are heavier smokers than our subjects, who smoked only 10-20 cigarettes per day.     

Meaning in Life: Does It Play a Role in Smoking?

The aim of this study was to investigate whether a relationship exists between a decreased level of meaning in life and smoking. In 2006, 341 Hungarian respondents (48.1% males, 51.9% females) completed a questionnaire that included the Purpose in Life test, a shortened version of the Aspiration Index and the Beck Depression Inventory, as well as questions about sociodemographic characteristics, past year alcohol and illicit drug consumption, and smoking behavior. The mean age of the participants was 33.0 years (SD = 14.6), while the average years of education of the respondents was 14.5 (SD = 2.7). According to the results of the regression analysis, meaning in life proved to be significant in differentiating between nonsmokers and daily smokers. With regard to the nonsmoker vs. occasional smoker and the daily vs. occasional smoker relationship, level of life meaning was not a significant predictor. The gender-meaning in life interaction was insignificant in all three relations. Limitations of this explorative investigation are noted.     

Individual changes in clozapine levels after smoking cessation: results and a predictive model.

Published reports document 20-40% lower mean serum clozapine concentrations in smokers compared with nonsmokers due to enzyme induction. Despite the increase in nonsmoking psychiatric facilities in the United States, previous studies have not tracked individual changes in serum clozapine levels after smoking cessation. Clozapine level changes were analyzed in 11 patients at Oregon State Hospital who were on stable clozapine doses, before and after implementation of a hospital-wide nonsmoking policy. A mean increase in clozapine levels of 71.9% (442.4 ng/ml +/- 598.8 ng/ml) occurred upon smoking cessation (p < .034) from a baseline level of 550.2 ng/ml (+/- 160.18 ng/ml). One serious adverse event, aspiration pneumonia, was associated with a nonsmoking serum clozapine level of 3066 ng/ml. Elimination of statistically extreme results generated a mean increase of 57.4 % or 284.1 ng/ml (+/- 105.2 ng/ml) for the remaining cases (p < .001) and permitted construction of a linear model which explains 80.9% of changes in clozapine levels upon smoking cessation (F = 34.9;p = .001): clozapine level as nonsmoker = 45.3 + 1.474 (clozapine level as smoker). These findings suggest that significant increases in clozapine levels upon smoking cessation may be predicted by use of a model. Those with high baseline levels should be monitored for serious adverse events.     

Smoking Restores Impaired LTD-Like Plasticity in Schizophrenia: a Transcranial Direct Current Stimulation Study

Impaired neuroplastic responses following noninvasive brain stimulation have been reported repeatedly in schizophrenia patients. These findings have been associated with deficits in GABAergic, glutamatergic, and cholinergic neurotransmission. Although various neurophysiological studies have indicated a relationship between nicotine and neuroplasticity in healthy individuals, the present study is the first investigation into the impact of nicotine on LTD-like plasticity in patients with schizophrenia. Cortical excitability and cortical plasticity were explored in 30 schizophrenia patients (17 smoker, 13 nonsmoker) and 45 healthy controls (13 smoker, 32 nonsmoker) by using single-pulse transcranial magnetic stimulation (TMS) before and following cathodal transcranial direct current stimulation (tDCS) applied to the left primary motor cortex. Our analysis revealed abolished LTD-like plasticity in nonsmoking schizophrenia patients. However, these plasticity deficits were not present in smoking schizophrenia patients. In healthy controls, significant MEP reductions following cathodal tDCS were observed in nonsmoking individuals, but only trend-level reductions in smokers. In smoking schizophrenia patients, the severity of negative symptoms correlated positively with reduced neuroplasticity, whereas nonsmoking patients displayed the opposite effect. Taken together, the data of our study support the notion of an association between chronic smoking and the restitution of impaired LTD-like plasticity in schizophrenia patients. Although replication and further research are needed to better understand this relationship, our findings indicate that nicotine intake might stabilize the impaired inhibition–facilitation balance in the schizophrenic brain through a complex interaction between cortical plasticity, and GABAergic and cholinergic neurotransmission, and might explain the reduced prevalence of negative symptoms in this population.     

Influence of cimetidine, sulfinpyrazone, and cigarette smoking on theobromine metabolism in man

Theobromine metabolism and clearance were investigated at steady-state under chronic oral dosing conditions in eight healthy volunteers, four of whom were cigarette smokers. The subjects were studied before and after separate 1 week pretreatments with cimetidine (1 g/day) and sulfinpyrazone (800 mg/day). Theobromine plasma clearance (ClTB) was 33% higher in smokers than in non-smokers due to induction of all metabolic pathways (3-demethylation, 7-demethylation, and formation of 6-amino-5-(N-methylformylamino)-1-methyluracil (AMMU]. 7-Demethylation was induced by cigarette smoking to a greater extent than the other pathways. Cimetidine pretreatment inhibited theobromine 3-demethylation and AMMU formation resulting in a 27% decrease in ClTB in the combined smoker/nonsmoker group. The 7-demethylation pathway was unaffected by cimetidine. In contrast, sulfinpyrazone pretreatment increased ClTB by 50% in the whole group by approximately equal induction of each metabolic pathway. The extent of induction due to sulfinpyrazone was 2.4-fold greater in nonsmokers than in smokers. When compared with previous data relating to theophylline, the results suggest that theobromine 3-demethylation is mediated by the same form(s) of cytochrome P-450 involved in theophylline demethylation, while a second form(s) of cytochrome P-450 is involved in theobromine 7-demethylation and theophylline 8-hydroxylation. In addition, since AMMU formation was inhibited by cimetidine and induced by cigarette smoking and sulfinpyrazone, it would appear that the conversion of theobromine to AMMU is also mediated by cytochrome P-450.