Hyperhomocysteinaemia: a risk factor for extracranial carotid artery atherosclerosis

Hyperhomocysteinemia arising from impaired methionine metabolism, and usually due to a deficiency of cystathionine ß-synthase is a significant and independent risk factor for symptomatic vascular disease. It is not known if hyperhomocysteinemia in apparently healthy asymptomatic subjects is associated with atherosclerosis and whether such a relationship is independent of conventional risk factors. The prevalence of asymptomatic extracranial carotid artery atherosclerosis was determined by duplex ultrasound examination in 25 obligate heterozygotes with respect for cystathionine ß-synthase deficiency (whose children were known to be homozygous for this genetic defect) and in 21 controls. Hyperhomocysteinemia was determined by a standard methionine-loading test and conventional risk factors were also recorded. Twelve of 25 obligate heterozygotes and 8 of 21 normal controls had evidence of extracranial carotid artery atherosclerosis. Hyperhomocysteinemia as a genetic trait was not a significant risk marker, but the actual homocysteine level was associated with an increased risk of carotid disease. After adjustment for the effects of other significant risk factors, the odds ratio of hyperhomocysteinemia for carotid disease was 1.038 per unit increase in homocysteine level (P=0.03). Hyperhomocysteinemia is a weak risk factor for asymptomatic extracranial carotid atherosclerosis and the relative risk associated with this genetic trait is less than that observed in a study of patients presenting with clinical manifestations of vascular disease.     

颈动脉颅外段粥样硬化对不同年龄段脑梗死的相关性研究

目的 探讨颈动脉颅外段粥样硬化与不同年龄段患者脑梗死的关系.方法 选取本院2008年1月至2010年1月诊治的130例脑梗死患者,根据患者年龄分布分为3组,即40～<56岁为A组,56～<66岁为B组,≥66岁为C组,分别测定并比较3组患者总胆固醇(TC)、三酰甘油(TG)、高密度脂蛋白 (HDL)、纤维蛋白原(FIB...     

Kuang Yao-lin邝耀麟，Chen Zhi-ping陈治平，Wu Zhi-yong吴志勇 Huang An黄 安，Yuan Ji-min袁济民，Zheng Zhong-hua郑忠华 Rerj i Hospital, Shanghai Second Medical University, Shanghai Xiao Shu-dong萧树东and Zeng Min-de曾民德 Shanghai Institute of Digestive Disease, Shanghai

This paper reports the real time B-mode Doppler scanning findings of the extracranial portion of carotid arterial system (CAS) in 182 healthy persons (119 males and 63 females). The results showed that the diameter of the lumen of common carotid artery (CCA), bifurcation of common carotid artery (BCCA) and internal carotid artery (ICA) was larger in males than in females; there was no relationship between the diameter of the lumen of CCA, BCCA and ICA and body height; the diameter of lumen of CCA increased with age; 29 cases of atherosclerosis of the arterial wall (11 lesions with thickening of intima, 16 with hard plaque, one with soft plaque and 5 with stenosis) were observed; and the incidence of positive findings of atherosclerotic lesion of extracranial portion of CAS in the 40-49 age group and 50-59 age group was only 4.2% and 4.8% respectively, while the incidence in those aged over 60 increased markedly to 26.5-41.7%. These suggested that incidence of atherosclerosis in extracranial portion of CAS was not low in healthy persons without any evidence of stroke. As atheromatous lesions may be related to the consequent onset of stroke in the future, follow-up study and repeated Doppler scanning are necessary so as to observe the relationship between the location and severity of the lesion and the occurrence of cerebrovasculor disease. They may be helpful in determining the indication for carotid artery operation and also play a role in the prevention and treatment of CVD.     

尼古丁依赖与烟瘾治疗

吸食烟草是世界上可以预防的致死、致残、引发疾病的重要因素之一,至2020年它可能成为所有发达国家和发展中国家要面对的头号健康问题。尼古丁是导致机体对烟草产生依赖的重要物质,作用于中枢神经系统,引起多巴胺等神经递质的释放。像其他产生依赖的化学物质一样,尼古丁被认为是激活中脑边缘多巴胺系统产生犒赏作用。有很多治疗尼古丁依赖的方法,目前被证实有效的有行为治疗（包括5A 简单干预）和药物疗法2种。研究发现, 5A 简单干预是最好的简短干预方法之一,特别适用于工作繁忙的内科医师治疗成瘾者。尼古丁替换替代疗法（如皮肤贴剂、口香糖、吸入剂、鼻喷雾液、糖锭）,安非他酮缓释剂和伐尼克兰3种药物疗法可用于解除烟瘾。伐尼克兰是一种新的α4β2尼古丁受体部分激动剂。III期临床试验显示,它可能比尼古丁替代和安非他酮更有效。伐尼克兰的常见不良反应有恶心等消化道症状,但较轻微,多可以忍受。但此药上市后有报告出现焦虑、抑郁和自杀的案例,故在伐尼克兰的使用说明中添加进了新的安全性警告。不过到目前为止,这些神经精神不良反应与服用伐尼克兰的因果关系尚未被证实。     

The smoking cessation process

The purpose of this study was to identify and describe the smoking cessation process as perceived by smokers and ex-smokers. In-depth, open-ended interviews were conducted with 25 ex-smokers who had quit smoking for at least 1 year, but not more than 7 years, and 22 smokers who had quit smoking for at least 2 weeks and returned to smoking. A systematic analysis of content was used to generate categories of responses regarding the smoking cessation process. The results of this study support and enhance what is known about behavioral change. Although further testing for verification is needed, the smoking cessation process as described by the study participants is: thinking about quitting, making a case, quitting, making adjustments, meeting the challenge, resumption, or maintenance.     

Cigarette smoking in pregnancy

It is likely that the most important example of passive smoking is that which is imposed on the fetus. An article in the April 18, 1988, issue of the "Medical Journal of Australia" makes it clear (Condon and Hilton) that great difficulties will be faced in dealing with the effects of smoking during pregnancy. Gritz (1980) examined the evidence for fetal toxicity from tobacco smoke and the risk ratios for the various hazards. The risk of spontaneous abortion is increased by a factor of 1.8, low birth weight by a factor of 2.0, and perinatal mortality by a factor of 1.35. These increases come as no surprise given what is known regarding the pathophysiology of tobacco's effect on the fetus and the placenta. Condon and Hilton report on the observation that pregnant women find it much easier to stop drinking alcohol than to quit smoking cigarettes. Women who reported positive feelings about their pregnancy also indicated that their concern about, and attachment to, their unborn child provided insufficient motivation to stop using nicotine. It is assumed that the women described in this article were aware of the risks to the fetus from smoking in that such information is available almost as a routine part of antenatal care, and all but 1 of the smokers did try to reduce or to stop their use of nicotine. Yet, 14 of the 35 smokers failed in their efforts to reduce their smoking; another 7 smokers could manage only a small reduction. The 23,000 tobacco-associated deaths/year support the importance of developing a strategy to deal with nicotine dependence, particularly in situations of high risk such as pregnancy. The most reasonable and potentially effective approach would be to expend energy on preventing or dissuading young women from smoking in the 1st place. Over the past decade there have been numerous efforts at mass-media and educational campaigns to dissuade women from smoking, but these efforts have been overwhelmed totally by the determined drive on the part of tobacco companies to recruit female smokers.     

Cigarette smoking and invasive cervical cancer

A case-control study of 480 patients with invasive cervical cancer and 797 population controls, conducted in five geographic areas in the United States, included an evaluation of the relationship of several cigarette smoking variables to cervical cancer risk. Although smoking was correlated with both age at first intercourse and number of sexual partners, a significant smoking-related risk persisted for squamous cell carcinoma after adjustment for these factors (relative risk, 1.5). The risk of squamous cell cancers increased significantly with intensity and duration of smoking. Twofold excess risks were seen for those smoking 40 or more cigarettes per day and those smoking for 40 or more years. In addition, users of nonfilter cigarettes were at particularly high risk. Increased risks, however, were observed only among recent and continuous smokers. In contrast to squamous cell cancer, no relationship was observed between smoking and risk of adenocarcinoma or adenosquamous carcinoma (n = 63). These results suggest a causal relationship between cigarette smoking and invasive squamous cell cervical cancer, perhaps through a late-stage or promotional event, although the mechanisms of action require further elucidation.     

Cigarette smoking and infertility in men

For this study of testosterone concentrations in 2 matched groups of men, 1 of lifelong nonsmokers and 1 of men smoking at least 30 cigarettes daily, 2 specimens of blood were collected with an interval of 7 days without smoking. The first specimens showed plasma testosterone to be higher in nonsmokers than in smokers, indicating that smoking decreases plasma testosterone. The difference in plasma testosterone between the 2 specimens from nonsmokers was insignificant, but in smokers the 2nd specimen showed a statistically significant increase in testosterone concentration. Reduced testosterone biosynthesis caused by carbon monoxide inhibition of Leydig cell microsomal hydroxylases seems to be the probable explanation of this effect. The possibility thus exists that cigarette smoking can contribute to infertility in men.     

Cigarette smoking and urinary organic sulfides

In order to observe how cigarette smoking influences levels of thio-thiazolidine-4-carboxylic acid(TTCA),high performance liquid chromatography(HPLC) was used to detect TTCA in urine from 18 healthy male volunteers.At the sme time,the total amout of urinary organic sulfides was determined by the iodine azide test(IAT).Nine of the volunteers had smoking higtories(5 to 10 cigarettes per day,as the smoking group),and the rest only occasionally smoke (1 to 2 cigarettes per month,as the control group).Samples were collected in the early morning (limosis)and 90 minutes after smoking a cigarette.Results showed that smoking a single cigaretter could elevate the level of urinary organic sulfides both in the smoking and control groups,while a smoking habit appeared to have no significant influence on the urinary organic sulfide level.No significant cumulative effect of cigarette smoking on urinary organic sulfides was found,The influence of cigarette on uinary organic sulfides was temporary.The results suggest that cigaretter smoking might be a confounding factor in biomontoring the levels of carbon disulfide in exposed workers.     

Therapy for cessation of smoking

Tobacco dependence is a chronic relapsing medical illness. Unfortunately more than 1.1 billion people worldwide smoke tobacco. Tobacco consumption rate is very high in India. Providing three minutes counseling by physicians doubles the cessation rate as compared to no intervention. Nicotine replacement products (gums, transdermal patch, nasal spray, inhaler and lozenge), bupropion and varenicline used with counseling by physicians double the cessation rates at one year. There are drugs like buspirone, naltrexone, mecamylamine and silver acetate; some of which either alone or in combination with any of the above drugs may be routinely used in near future for smoking cessation in at least some specific groups of population. The most difficult problem for patients in smoking cessation is withdrawal symptoms. Counseling with continuous support from physician, family members, friends and overall from the society will help in achieving a higher rate of smoking cessation, with the final aim of making ours a tobacco smoke-free world for future generations.