Lack of effect of cimetidine on cigarette smoking

Summary The efficacy of cimetidine as a treatment that could reduce smoking in heavily dependent smokers has been determined. In a randomised, double-blind, double-crossover experiment, 43 heavy smokers were divided into two groups, one receiving cimetidine 400 mg orally three times a day, and the other receiving placebo for two weeks followed by the alternative treatment (placebo or cimetidine).No significant difference in the mean alveolar carbon monoxide, nicotine or cotinine levels was found between the two treatment groups compared to baseline. Since the alveolar carbon monoxide level reflects the intensity of smoking behaviour, the results suggest that no change in smoking behaviour occurred in the subjects.Contrary to our previous findings that cimetidine decreased the total body clearance of nicotine by 30% in a population of non-smokers, in the heavily dependent smokers, cimetidine did not appear to alter nicotine elimination. One possible explanation for the discrepancy is that tobacco smoking is known to induce nicotine metabolism and the induction might have offset any effect of cimetidine on nicotine elimination.Cimetidine does not appear to be a useful treatment leading to a reduction or cessation of cigarette smoking.     

Positive Outcome Expectancies and Smoking Behavior: The Role of Expectancy Accessibility

This study examined the association between smoking outcome expectancy accessibility and smoking behavior. Daily smokers completed a smoking expectancy accessibility task in which they made timed judgments to a series of positive consequences of smoking either after 6 hr deprivation or within 10 min of smoking. Participants then completed a questionnaire battery that contained assessments of smoking behavior and smoking outcome expectancies. Results of hierarchical regression analyses showed that expectancy accessibility was associated with the number of cigarettes smoked per day even when controlling for corresponding questionnaire measures of smoking expectancies. Moreover, smoking expectancy accessibility predicted urge to smoke ratings following exposure to a smoking cue after controlling for the effects of deprivation. Findings suggest that smoking expectancy accessibility may play a central role in smoking behavior and that individual differences in this attribute may be assessed directly through reaction time assessment.     

苹果提取物抗辐射效应的研究

目的 :　研究苹果提取物的组成成分及其抗辐射效应。方法 :　利用分光光度法及HPLC法分析苹果提取物中酚类物质 ,并采用灌胃方式给予实验小鼠 ,连续灌胃 30 d后接受 7Gy60 Co-γ射线一次性辐照 ,照射后一半动物取血进行白细胞计数 ,另一半动物观察平均存活时间和 30d存活率。结果 :　 (1 )苹果提取物中主要的酚类成分为原花青素低聚体 ,儿茶素单体 ,酚酸 ,黄酮等酚类物质。 (2 )灌胃高剂量苹果提取物 30 d的小鼠经 7Gy一次性辐射后 ,第 7d小鼠白细胞数量比辐射对照组提高了 1 1 2 % (P<0 .0 1 ) ,第 1 4 d小鼠白细胞数量提高了 52 % (P<0 .0 5) ;且苹果提取物高剂量组小鼠的 30 d存活率明显高于辐射对照组 (P<0 .0 5)。 (3)服用中、高剂量的小鼠比辐射对照组平均存活天数分别提高了 72 % (P<0 .0 1 )和 69% (P<0 .0 1 )。结论 :　苹果提取物对 7Gy剂量一次性照射具有拮抗作用。其主要成分可能为原花青素低聚体 ,儿茶素等酚类物质。     

主动吸入药物烟对大鼠一氧化氮的影响

目的　探讨主动吸入药物烟对大鼠NO的影响。方法　制备大鼠主动吸烟模型 ,采用硝酸还原酶法测定各组大鼠血清、肺、心肌及脑组织的NO含量。结果　非药物烟组大鼠血清、肺、心肌及脑组织中NO含量明显低于非给烟对照组 ,药物烟高、中剂量组NO含量明显高于非药物烟组 ,接近非给烟对照组。结论　吸烟对大鼠血液、肺、心肌及脑组织有不同程度的损伤作用 ,使NO含量降低 ;药物烟具有一定的保护和防止NO含量降低的作用。     

香烟烟雾吸入对大鼠局灶性脑缺血后梗死灶的影响

目的 观察香烟烟雾吸入对大鼠局灶性脑缺血后梗死灶的影响，探讨其机制。方法 建立吸烟大鼠模型。用TTC染色法测定梗死灶体积，检测大鼠局灶性脑缺血后神经功能缺陷评分及梗死灶体积占同侧半球百分比。结果 除戒烟组外各吸烟组大鼠神经功能缺陷评分及梗死灶体积与对照组相比显著增加，吸烟4周、8周及12周依次增加。戒烟组神经功能评分及梗死体积明显低于吸烟4周组，与对照组无显著差别。结论 吸烟可加重大鼠局灶性脑缺血后脑组织损害，且随着吸烟时间增加而加重，戒烟可使这种脑损害得到一定程度的恢复。     

Case-control study of silicosis, silica exposure, and lung cancer in white South African gold miners

A case-control study was undertaken to assess the association between lung cancer and silicosis or silica dust exposure in white South African gold miners. Cases and controls were identified from deaths reported to the Gold Miners Provident Fund for the period January, 1979-October, 1983. Two controls were matched to each case by year of birth (+/- 2 years) and by smoking (+/- 5 cigarettes or equivalents per day) assessed 10 years (+/- 2 years) prior to death. One hundred thirty-three matched triplets were identified. The results showed no overall association between lung cancer and radiological silicosis (OR = 1.08, p = 0.92). Autopsy data indicated no overall associations between lung cancer and silicosis of the lung parenchyma (OR = 1.49, p = 0.11), the pleura (OR = 0.72, p = 0.30), or the hilar glands (OR = 0.85, p = 0.72). A trend toward increased severity of silicosis of the parenchyma was evident; however, this was not statistically significant (p = 0.08). Odds ratios for lung cancer and silicosis were higher at lower levels of cumulative silica dust exposure (ORs = 2.43, 1.72, 1.35 and 0.62 for lung cancer and autopsy silicosis of the parenchyma for the lowest, second, third, and highest quartiles of dust exposure, respectively; all p greater than 0.05). Cases did not differ from controls for total silica dust exposure, length of exposure, weighted average intensity of exposure, or number of shifts at high dust (all p greater than 0.20). The data do not support the hypothesis of a carcinogenic role for silica dust and no statistically significant associations were found between lung cancer and silicosis.(ABSTRACT TRUNCATED AT 250 WORDS)     

被动吸烟与婴幼儿呼吸系统疾病及生长发育关系的研究

目的 探讨被动吸烟对婴幼儿乎吸系统疾病发病及对生长发育的影响。方法 将我院保健科负责保健的0～3岁的婴幼儿400名，以家长是否吸烟分为被动吸烟组和对照组，每组200名，定期询问患病史，同时翻身高、体重对其进行评价，追踪观察，经统计学处理后进行分析。结果 婴幼儿乎吸系统疾病的发病与被动吸烟密切相关，被动吸烟影响婴幼儿的生长发育，与国内外的相关报道基本一致。结论 被动吸烟对婴幼儿健康速成严重损害，如不加以保护，有演变为严重社会问题的危险。     

Improvement of fruit allergenic extracts for immunoblotting experiments

A method based on ion-exchange column chromatography to enhance the protein content of fruit allergenic extracts was found to help make the subsequent SDS-PAGE immunoblotting assays possible; otherwise, they were difficult to achieve due to the high carbohydrate content. Fractionated extracts of apple, pear, and peach (peel and pulp) were obtained by anion-exchange chromatography (Q-Sepharose^TM column), providing clear electrophoretic patterns which allowed IgE detection by enzymatic assays of the transferred membranes. This chromatographic method produced in one single step an enriched extract directly from the standard crude aqueous one, with an increment in the protein content of more than sixfold, on average; thus, it proved to be more suitable than the usual chemical fractionation procedures.     

麦胚提取物对辐射损伤修复的实验研究

目的 研究麦胚提取物对小鼠辐射损伤修复的调节和保护作用。方法 采用辐射前或辐射同时饲喂一定量的麦胚提取物，观察小鼠经X射线一次性全身照射后的临床症状、30d存活率、骨髓微核率、外周血白细胞总数在不同时间的变化。结果 与对照组(单纯照射)比较，饲喂麦胚提取物可使小鼠的头面部皮肤、小肠黏膜、肾脏损伤症状得到明显改善；30d存活率为86．17％(P＜0．01)，提高存活率41．79％，保护系数为1．72；骨髓微核率4．62‰；比对照组(12．14‰)降低(P＜0．01)；外周血白细胞总数在7，13，20，30d均显回升(P＜0.05，P＜0．01，P＜0．01，P＜0．01)。结论 麦胚提取物对小鼠辐射损伤修复有一定程度的调节和保护作用，对于辅助肿瘤放射治疗具有重要意义。