CYP2A6 genetic variation and potential consequences

Human cytochrome P450 2A6 (CYP2A6) has been shown to have large interindividual and interethnic variability in levels of expression and activity. This is thought to be largely due to genetic polymorphisms. In recent years, 13 genetic variants (CYP2A6*1-*11 and the gene duplication, *1 x 2) of CYP2A6 have been identified and a number of these have been shown to result in altered CYP2A6 enzyme activity. For example, there are alleles which result in variants that are in inactive (e.g. due to a gene deletion), have decreased activity (e.g. altered enzyme structure or transcriptional activity) or have increased activity (e.g. due to gene duplications). The resulting interindividual variation in metabolic activity may affect the metabolism of CYP2A6 substrates including nicotine, cotinine (the major metabolite of nicotine), several tobacco-specific procarcinogens, coumarin and many toxins. The frequencies of the CYP2A6 alleles vary considerably among different ethnic populations, which may partially explain the interethnic variability found in CYP2A6-related metabolic activity (e.g. nicotine metabolism), behaviors (i.e. smoking) and disease (i.e. lung cancer). Investigations of the genetic variation of CYP2A6 and its resulting effects on metabolism and health consequences are still fairly early; this review summarizes what is presently known about CYP2A6, its genetic variants and their clinical consequences.

Correlation between a single nucleotide polymorphism in the matrix metalloproteinase-2 promoter and risk of lung cancer

Matrix metalloproteinases (MMPs) play an important role in several steps of cancer development. A single nucleotide polymorphism (-1306C-->T) in the MMP2 promoter sequence disrupts an Sp1 site and thus results in strikingly lower promoter activity. We examined the relationship between this polymorphism and risk for lung cancer in 781 cases and 852 age- and sex-matched controls in a Chinese population. We found that the allele frequency of MMP2-1306C was significantly higher among cases than among controls (0.91 versus 0.83). Subjects with the CC genotype had an overall 2-fold increased risk for developing lung cancer [adjusted odds ratio (OR) 2.18; 95% confidence interval (CI), 1.70-2.79] compared with those with the CT or TT genotype. The elevated risk was observed evenly among different subtypes of this cancer. Stratified analysis indicated an additive interaction between the CC genotype and smoking on the elevated risk. The ORs of lung cancer for the CC genotype, smoking, and both factors combined were 2.38 (95% CI 1.64-3.45), 4.26 (95% CI 2.57-8.44), and 7.64 (95% CI 4.74-12.33), respectively. Furthermore, when the data were stratified by the pack-years smoked, this joint effect was more evident and stronger in heavy smokers (OR 10.25, 95% CI 5.80-18.09) than in light smokers (OR 5.55, 95% CI 3.34-9.22). These results demonstrate a significant association between the MMP2 -1306C/T polymorphism and risk of developing lung cancer solely or in a manner of interaction with carcinogen exposure.

Pi*S and Pi*Z alpha 1 antitrypsin polymorphism and the risk for asbestosis in occupational exposure to asbestos

Alpha 1 antitrypsin is a highly polymorphic anti-elastase enzyme, especially active in the protection of alveoli and liver. Here we studied the distribution of two deficient alleles Pi*Z and Pi* S, in 194 asbestos workers, of whom 100 were asbestosis cases, and 94 were controls without disease (exposed controls, EC). A second group of controls without asbestos exposure (non-exposed controls, NEC; n=122) was also included. Multivariate analysis adjusted by age and smoking habit showed ninefold risk for asbestosis in Pi*Z heterozygous individuals and 5.9-fold risk for Pi*S homozygous although differences were only significant in the first case (cases vs. EC: OR 8.9; p=0.04). Considering both genotypes (Pi*Z heterozygous, Pi*S homozygous) we obtained an OR of 8 (p=0.01). Our results suggest that the alpha 1 antitrypsin polymorphisms, especially Pi*Z, could help to predict asbestosis risk and confirm the high prevalence of the Pi*S allele in Spain.

Effects of smoking cessation or reduction on hormone profiles and bone turnover in postmenopausal women

The purpose of this study was to prospectively evaluate the impact of smoking cessation on hormonal concentrations, sex hormone-binding globulin (SHBG) and markers of bone turnover in postmenopausal women. Sixty-six women who were either users or non-users of estrogen replacement therapy (ERT) were randomly assigned, using a weighted randomization scheme, to smoking cessation (SC) or to smoking cessation after 6 weeks of monitoring (wait-list control group, WLC). We measured hormones [estrone, estradiol, testosterone, parathyroid hormone, dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS) and androstenedione] and SHBG, markers of bone turnover [procollagen peptide (PINP), bone alkaline phosphatase (BAP), and osteocalcin (OC), N- and C-terminal collagen cross-links (NTx and CTx)], and cotinine, at baseline and again at 6 weeks in women who reported smoking cessation and in women randomized to the WLC group. Analyses included 20 subjects who quit or significantly reduced their smoking and 18 subjects in the WLC group. After controlling for differences in age and ERT use between groups, we found a significant change in SHBG in the SC vs. the WLC group (-8% vs. +5%, respectively; p = 0.01), and in DHEA (-18% vs. -5%, respectively; p = 0.04), but not in other hormonal concentrations. We also noted a significant change in NTx in the SC vs. WLC group (-5% vs. +56%, respectively, p = 0.01), but not in other markers of bone turnover. Percentage changes in SHBG and NTx were correlated with changes in plasma cotinine (r = 0.48; p = 0.004 and r = 0.36; p = 0.04, respectively). Six weeks of smoking abstinence produces reductions in SHBG and NTx. This may partly explain how smoking contributes to osteoporosis in postmenopausal women.

Specific p53 immunostaining patterns are associated with smoking habits in patients with oral squamous cell carcinomas

AIMS

To identify immunostaining patterns that are predictive for p53 mutations and to investigate whether p53 mutations are associated with established risk factors for oral squamous cell carcinoma (OSCC).

METHODS

Fifty five OSCCs were investigated for p53 protein expression by immunohistochemistry (IHC). Ten of these cases, including five p53 immunopositive and five p53 immunonegative cases, were subjected to microdissection of representative tumour areas followed by sequence analysis for the detection of TP53 mutations.

RESULTS

Paired IHC and sequence analysis revealed that p53 immunoexpression in more than 25% of tumour cells was indicative of TP53 mutations, whereas p53 immunonegativity was not informative. Therefore, for p53 immunohistochemical interpretation, p53 immunonegative cases were excluded from the analysis and the cut off value for p53 immunoexpression was set at 25%. Of the OSCCs showing any p53 immunoexpression, 64% revealed staining in more than 25% of the tumour cells. p53 immunoexpression in more than 25% of the neoplastic cells was significantly associated with smoking but not with alcohol consumption. No significant association with smoking habits was found when OSCCs were dichotomised into p53 immunonegative and p53 immunopositive.

CONCLUSIONS

In OSCCs the following conclusions can be made: (1) p53 immunonegativity is not informative for TP53 mutations; (2) 25% p53 immunopositive cells appears to be a good cut off value to predict TP53 mutations; (3) p53 immunostaining patterns that appeared to be predictive for TP53 mutations were associated with the smoking habits of the patients.

Toenail nicotine levels as a biomarker of tobacco smoke exposure

Currently used biomarkers of tobacco smoke exposure have several disadvantages, including that they reflect short-term exposure and can therefore be affected by day-to-day variations. The aim of this study was to assess the validity of toenail nicotine levels as a biomarker of exposure to tobacco smoke for use in epidemiological studies. Toenails were collected in 1982 from 62,641 women participating in the Nurses' Health Study, whereas questionnaire data at that time provided information on active and passive smoke exposure. A stratified random sample of stored toenails from 106 women were selected according to their reported exposure category. Toenails were analyzed for nicotine levels by high-performance liquid chromatography. Toenail nicotine levels differed significantly according to tobacco smoke exposure (P < 0.0001). Among nonactive smokers, there was a significant difference in toenail nicotine levels between passive smokers (mean = 0.28 ng/mg) and nonexposed women (mean = 0.08 ng/mg; P = 0.0006). Among active smokers, there was also a significant difference (P = 0.04) in mean nicotine levels according to categories of cigarettes smoked (means for smokers of 1-14, 15-24, and 25 or more cigarettes/day were 0.94, 1.81, and 2.40 ng/mg). An overlap of the distribution of nicotine levels among passive and active smokers was found. Among all women, the correlation between nail nicotine levels and smoking exposure categories was r = 0.80 (P < 0.0001). The results of this study indicate that toenail nicotine level measurement is a valid biomarker for assessment of active and passive exposure to tobacco smoke. Nail nicotine levels may reflect aspects of active and passive exposure not captured by standard questionnaires and, thus, have the potential to provide better assessment of associations with health risk.

Abnormal movements and tardive dyskinesia in smokers and nonsmokers with schizophrenia genotyped for cytochrome P450 2D6

STUDY OBJECTIVE

To investigate the relationships between cytochrome P450 (CYP) 2D6 genotype, antipsychotic drug exposure, abnormal movements and tardive dyskinesia, and cigarette smoking.

DESIGN

Prospective, longitudinal study.

SETTING

University mental health research center.

PATIENTS

Thirty-seven patients with schizophrenia.

INTERVENTION

Patients were genotyped for CYP2D6*1, *3, and *4 alleles, and data were collected on their psychiatric symptoms, cigarette smoking status, and antipsychotic drug exposure. Abnormal movements were measured using the Abnormal Involuntary Movement Scale (AIMS). Presence of tardive dyskinesia was also evaluated.

MEASUREMENTS AND MAIN RESULTS

A linear regression model used the AIMS scores as the dependent variable, and genotype, sex, smoking status, and antipsychotic drug exposure as independent variables. Antipsychotic drug exposure, genotype, and cigarette smoking interaction was significant (p<0.0212) for patients with the CYP2D6*1/*3, *4 genotype. Seventy-eight percent of smokers with the CYP2D6*1/*3, *4 genotype had tardive dyskinesia compared with 20-33% of patients in other groups.

CONCLUSION

Patients with a CYP2D6*3 or *4 allele may shunt antipsychotic metabolism through other pathways that are induced by cigarette smoke. This induction may result in formation of neurotoxic metabolites, leading to increased AIMS scores and a higher frequency of tardive dyskinesia compared with patients without these alleles.

Acetaldehyde in mainstream tobacco smoke: formation and occurrence in smoke and bioavailability in the smoker

A review is presented of the scientific literature on the effects of sugars (mono- and disaccharides), when used as tobacco additives, on the formation of acetaldehyde in mainstream (MS) smoke and the potential bioavailablity of MS smoke acetaldehyde derived from sugars to the smoker. The experimental data supports the following conclusions. Sugars, e.g., D-glucose, D-fructose, and sucrose, do not produce greater yields of acetaldehyde in MS smoke than are produced from tobacco itself on a weight-for-weight basis. A variety of studies suggests that natural tobacco polysaccharides, including cellulose, are the primary precursors of acetaldehyde in MS smoke. In a number of different studies using commercial cigarette brands, MS smoke yields of acetaldehyde correlate (r > 0.9) with both MS smoke "tar" and carbon monoxide. MS smoke acetaldehyde yields are affected more by cigarette design characteristics that influence total smoke production, such as filter ventilation, filtration, and paper porosity, than by reducing sugars. MS smoke acetaldehyde deposits primarily in the upper respiratory tract, including the mouth, of the smoker. Acetaldehyde is rapidly metabolized by aldehyde dehydrogenase in the blood and elsewhere in the body, including at the blood-brain barrier. Tobacco sugar-derived MS smoke acetaldehyde from commercial cigarettes is unlikely to result in direct central nervous system effects on the smoker.

[The detection of DNA adduct in human peripheral lymphocytes by bioluminescence method]

OBJECTIVE

To develop bioluminescence method to measure DNA adducts in human peripheral lymphocytes and study the factors that affect the level of DNA adduct, in order to use it in studying the relationship between water pollution and human DNA adduct levels.

METHOD

The measurement of DNA adduct in peripheral lymphocytes was carried out in 234 normal persons, and the relationship between DNA adducts levels and age, smoking and eating habit etc. was analyzed.

RESULTS

(1) The level of DNA adduct in males was higher than that in females, but without significance (P > 0.05); (2) The level of DNA adduct was significantly correlated with age, smoking, tea drinking, eating habit and alcohol drinking. Among them, age plus smoking were the most important factors affected the DNA adduct levels (P < 0.01). The level of DNA adduct increased with age. The more cigarette smoked, the higher was the level of DNA adduct.

CONCLUSION

The level of DNA adduct is affected by many factors, so it needs further research to apply it in the biomonitoring and risk assessment of environment chemicals.

Serum nitrates and vasoactive intestinal peptide in patients with gastroesophageal reflux disease

BACKGROUND

The normal esophageal motility is a balance between excitatory cholinergic "muscarinic" innervations and noncholinergic nonadrenergic inhibitory innervations. The latter is mediated by nitric oxide (NO) and/or vasoactive intestinal polypeptide (VIP).

METHODS

The study included 50 patients with gastro-esophageal reflux disease (GERD), and 10 healthy controls of matched age and sex. Patients were divided into five groups according to the degree of lower end esophagitis (Savary-Miller classification). Serum VIP was measured using enzyme immunoassay after peptide purification. Serum nitrate as an index of nitric oxide generation was determined biochemically.

RESULTS

Serum nitrate and VIP levels were significantly higher in GERD patients than the control group (p < 0.001). Grade 0 serum nitrates was significantly higher than the control group (p < 0.05) with some overlap between the individual values of the two groups. Serum VIP was significantly higher in grade 0 group compared to control group (p < 0.001) with no overlap in the individual values. There was a significant positive correlation between the grade of lower end esophagitis and each of serum nitrate and VIP (p < 0.001), as well as between serum nitrate and each of serum VIP, cigarette smoking index (CSI) and BMI (p < 0.001).

CONCLUSION

Abnormally high levels of serum VIP and NO may have a role in the pathogenesis of GERD. Exposure of esophageal mucosa to noxious effect of acid refluxed due to the relaxant effect of VIP on lower esophageal sphincter may cause increased NO levels. BMI and CSI are risk factors for GERD progression.

Correlation of the genotypes for N-acetyltransferases 1 and 2 with double bladder and prostate cancers in a case-comparison study

BACKGROUND

The arylamine N-acetyltransferases play a major role in the metabolic activation of carcinogenic amines that are present in cigarette smoke and a variety of other exogenous sources. The objective of this study was to determine the association of rapid or slow arylamine N-acetyltransferase (NAT) genotypes with smoking history and the risk for developing both bladder and prostate cancer.

PATIENTS AND METHODS

The subjects analyzed were a case group of 17 double-cancer patients and 34 age-matched controls who had benign prostatic hypertrophy, but were asymptomatic for prostate or bladder cancers. Genotyping of NAT1 and NAT2 alleles was done by restriction fragment length polymorphism and/or sequencing of NAT genes amplified from genomic DNAs by the polymerase chain reaction (PCR).

RESULTS

No significant correlation was found between NAT1 genotypes, double cancer, and smoking history. While NAT2-smoking interaction gave an odds ratio of only 1.70 (p = 0.117), a disproportionate number of cancer cases were genotypically rapid: 12 of 17 cancer cases vs. 13 of 34 controls (odds ratio 3.88; p = 0.040).

CONCLUSION

Rapid NAT2 genotype correlated significantly with the development of double prostate-bladder cancer.

Cognitive mechanisms of nicotine on visual attention

Understanding nicotine's neurobiological and cognitive mechanisms may help explain both its addictive properties and potential therapeutic applications. As such, functional MRI was used to determine the neural substrates of nicotine's effects on a sustained attention (rapid visual information-processing) task. Performance was associated with activation in a fronto-parietal-thalamic network in both smokers and nonsmokers. Along with subtle behavioral deficits, mildly abstinent smokers showed less task-induced brain activation in the parietal cortex and caudate than did nonsmokers. Transdermal nicotine replacement improved task performance in smokers and increased task-induced brain activation in the parietal cortex, thalamus, and caudate, while nicotine induced a generalized increase in occipital cortex activity. These data suggest that nicotine improves attention in smokers by enhancing activation in areas traditionally associated with visual attention, arousal, and motor activation.

Smoking-related increase of O(6)-methylguanine-DNA methyltransferase expression in squamous cell carcinoma of the esophagus

DNA repair protein O(6)-methylguanine-DNA methyltransferase (MGMT) has a defensive role against alkylating agents associated with increased incidence of malignant tumors. The aim of the current study was to elucidate the significance of immunohistochemical expression of MGMT in squamous cell carcinoma (SCC) of the esophagus, with a special reference to the correlation of smoking. Immunohistostaining of MGMT was performed in the specimens collected from 100 patients with SCC of the esophagus. The relationship between the personal history of smoking and MGMT expression was examined and the value of Brinkman index was compared between patients with and without MGMT expression. Fifty-five SCCs (55.0%) had a positive response to MGMT inununostaining. The proportion of patients who had tumors with MGMT expression among patients with smoking habits was 62.0% (49 out of 79), which was significantly higher than that among patients without smoking habits (28.6%, 6 out of 21; P=0.005). The mean value of Brinkman index in patients who had tumors with MGMT expression (1189+/-604) was significantly higher than that in patients who had tumors without MGMT expression (871+/-656; P=0.020). Our results suggested that MGMT expression in esophageal SCC might be correlated with smoking habits of the patients.

Tobacco smoking, harm reduction, and biomarkers

The only known way to reduce cancer risk in smokers is complete cessation, but many smokers are unable or unwilling to quit. Consequently, tobacco companies are now marketing products that purport to reduce carcinogen exposure, with the implication that such products provide a safer way to smoke. Moreover, researchers are exploring ways to reduce the amount of cigarette smoke carcinogens to which the smokers are exposed. Although these methods are, in theory beneficial, it is possible that the perceived availability of "safe" ways to smoke will cause some former smokers to resume smoking and some current smokers to delay quitting. Thus, the extent of exposure reduction and the impact on public health of these methods need to be considered carefully. However, risk reduction and its relation to exposure are not simple to estimate. The way people smoke and the way they respond to carcinogen exposure are both highly variable, as evidenced by the previous history of smokers who switched to light, or low-tar cigarettes. This can actually increase risk in some smokers. The evaluation of exposure reduction will therefore need to be multidisciplinary and include in vitro cell culture studies, animal studies, human clinical studies, and epidemiologic studies. Biomarkers will be critical for rapidly evaluating the effects of new strategies or products to reduce exposure to tobacco smoke carcinogens. No single biomarker will likely satisfy our assessment needs, and so a panel of biomarkers should be used that includes biomarkers of exposure, biologically effective dose, and potential harm. In addition, usefulness of new products will need to be tested in people of different susceptibilities (i.e., who vary in behavior, sex, age, genetics, and prior tobacco use). Even if the new products are shown to be effective at reducing lung carcinogens, they should not be used alone but rather be incorporated into a comprehensive tobacco control program.

Gender difference in the interaction of smoking and monoamine oxidase B intron 13 genotype in Parkinson's disease

We tested for gender-specific interactions between smoking and genetic polymorphisms of monoamine oxidase B (MAO-B) intron 13 (G or A allele), monoamine oxidase A (MAO-A) EcoRV (Yor N allele), and dopamine D2 recepor (DRD2) Taq1B (B1 or B2 allele) in a case-control study of 186 incident idiopathic Parkinson's disease (PD) cases and 296 age- and gender-matched controls. The odds ratios (ORs) for PD risk for ever smokers versus never smokers were 0.27 (95% CI: 0.13-0.58) for men of genotype G, and 1.26 (0.60-2.63) for men of genotype A (interaction chi2 = 8.14, P = 0.004). In contrast, for women, the OR for ever smokers versus never smokers were 0.62 (95% CI: 0.25-1.34) and 0.64 (95% CI: 0.18-2.21) for women of genotype GG/GA and AA, respectively (interaction chi2 = 0.001, P = 0.975). No interactions were detected between smoking and either MAO-A EcoRV or DRD2 Taq1B genotypes. These results suggest that a strong gender difference exists with respect to the modifying effect of MAO-B genotype on the smoking association with PD.

Dopamine D1 and D2 receptor mRNA up-regulation in the caudate-putamen and nucleus accumbens of rat brains by smoking

Nicotine, the toxic substance that is exclusively absorbed from smoking, produces a wide array of behavior and collectively propels drug-seeking behaviors when abused. The neurotransmitter dopamine (DA) is important in the reward and reinforcing properties of many addictive drugs: however, the effect of nicotine by cigarette smoking itself on the expression of DA receptors in the caudate-putamen (CPu), nucleus accumbens (NAc) and olfactory tubercle (OTu) has not been elucidated completely. Hence, the effects of smoking and nicotine on DA receptors need to be defined. In this research, the effect of smoking and nicotine addiction on the DA D1 and D2 receptors in the rat CPu, NAc and OTu were studied. Adult male Spraque-Dawley (S.D., n=50) rats were administered with cigarette smoke (passive inhaled for 10 min and 1 h, 500 ml x 3 times/day, 4 weeks) and nicotine (oral, 3 mg/day). DA D1 and D2 receptor mRNA levels were determined by in situ hybridization and RNase protection assay (RPA). In the smoking groups (10 min and 1 h), DA D1 and D2 receptor mRNA greatly increased in the CPu and NAc, and most of all in the NAc. The nicotine treated group showed increased expression of DA D1 and D2 receptor mRNA too, but statistically less than in the smoking group. In the smoking group, DA D1 and D2 receptor mRNA levels were significantly higher in the CPu and NAc than in the nicotine group (P<.01). These results suggest that smoking and nicotine administration both influence DA receptor mRNAs in the CPu, NAc and OTu, in terms of up-regulation. The up-regulation was much more evident in the smoking group than in the nicotine group. In conclusion, we believe that smoking up-regulate the DA receptor mRNA expression significantly higher in rat CPu and NAc than nicotine but only a little bit higher in OTu.

Alveolar macrophage-mediated elastolysis: roles of matrix metalloproteinases, cysteine, and serine proteases

Chronic obstructive pulmonary disease (COPD) is a common lung disease with cigarette smoking as the major etiological factor, but only 15% of smokers develop COPD. Destruction of lung elastin observed in COPD is mediated by many enzymes, including cysteine, serine, and matrix metalloproteinases (MMP). The contribution of these enzymes to the lung elastolytic load, released from alveolar macrophages collected from nonsmokers, healthy smokers, and COPD patients, was examined by radiolabeled elastin as substrate in the presence of specific enzyme inhibitors. The activity of MMP was further examined by zymography and Western blotting. COPD macrophages degraded more elastin than either of the other groups. Elastolysis was greatest in the initial 24 h. Through the 72-h culture period, the contribution to elastolysis of serine elastases decreased, MMP increased, and cysteine elastases remained constant. The increased release of elastolytic enzymes in COPD subjects may explain why some smokers develop COPD. This difference may be due to unknown susceptibility factors. Serine proteases play a significant role; however, other enzymes, particularly the MMP, deserve further investigation.

Correlation and predictive performances of saliva and plasma nicotine concentration on tobacco withdrawal-induced craving

AIMS

To investigate whether saliva is a useful alternative to plasma for routine monitoring of nicotine and evaluate the predictive performances of saliva and plasma concentration on craving estimated by a Tiffany Questionnaire on Smoking Urge-Brief Form.

METHODS

Thirteen healthy smokers were enrolled in a randomized, two period, crossover trial. Linear and power models were evaluated to predict the plasma nicotine concentrations from the saliva measurements, whereas a population PK/PD indirect response model was used to predict craving using either saliva or plasma nicotine concentration as the independent variable.

RESULTS

The results of the analysis revealed that the power model was preferred over the linear one. The bias on the predicted plasma concentrations was of 0.47 ng ml-1 with a 95% confidence interval of [-0.57, 1.52] and a precision of 5.68 ng ml-1. The placebo effect model was initially fitted to data, then the indirect response approach (with inhibition in k(in)) was used to model the craving scores using plasma and saliva nicotine concentrations as independent variables. The two indirect response PK/PD models based on saliva and plasma nicotine concentrations, adequately described the onset, extent, and duration of craving. The maximal inhibition I(max) was 0.722 and 1 for saliva and plasma concentrations while the estimated nicotine concentrations giving 50% of the maximal inhibition were 269 ng ml-1 and 24.3 ng ml-1 for saliva and plasma, respectively.

CONCLUSIONS

A good correlation between plasma and saliva nicotine concentrations has been found using a power model. Comparable values of bias and precision on the model-predicted craving indicate that plasma and saliva concentration can equally well be used to predict the onset of tobacco withdrawal induced craving. Analysis of saliva definitely offers a potentially more attractive way to assess nicotine concentration values, as samples can be collected easily and noninvasively. In addition, saliva sampling avoids the pain and discomfort involved in venepuncture. In studies that assess psychological measures, such as subjective mood, blood collection could present a possible confounding factor because of the anxiety and pain that accompanies it. For these reasons saliva can reasonably be considered as the ideal sampling site for all clinical studies conducted for the evaluation of the potential activity of drugs on nicotine deprivation symptoms.

Nicotine decreases bradykinesia-rigidity in haloperidol-treated patients with schizophrenia

We applied nicotine 21 mg and matching placebo transdermal patches to thirty haloperidol-treated patients with schizophrenia who smoked. Clinical assessments of bradykinesia-rigidity were lower during nicotine patch administration than during placebo patch administration.

The interaction of cigarette smoking and antioxidants. Part I: diet and carotenoids

It is logical that the requirement for antioxidant nutrients depends on a person's exposure to endogenous and exogenous reactive oxygen species. Since cigarette smoking results in an increased cumulative exposure to reactive oxygen species from both sources, it would seem cigarette smokers would have an increased requirement for antioxidant nutrients. Logic dictates that a diet high in antioxidant-rich foods such as fruits, vegetables, and spices would be both protective and a prudent preventive strategy for smokers. This review examines available evidence of fruit and vegetable intake, and supplementation of antioxidant compounds by smokers in an attempt to make more appropriate nutritional recommendations to this population.

Interleukin-1beta, tumor necrosis factor-alpha levels and neutrophil elastase activity in peri-implant crevicular fluid

The aim of this study was to determine interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha) levels and neutrophil elastase (NE) activity in peri-implant crevicular fluid (PICF) of smoker and nonsmoker patients, and to investigate their relationships with clinical parameters. A total of 42 endosseous root-form dental implants of 14 patients were clinically examined by modified Plaque index (PI), modified Gingival index (GI) and probing depth (PD). Smoking habits of the patients were recorded. PICF of implants were collected by Periopaper strips and IL-1beta, TNF-alpha levels were determined by enzyme-linked immunosorbent assay (ELISA). NE was analyzed with a neutrophil specific chromogenic substrate, N-methoxysuccinyl-Ala-Ala-Pro-Val-p-nitroanilide. The cytokine and enzyme levels in PICF were expressed as total amount/activity and as concentrations. NE activity in PICF significantly correlated with GI and PD, and IL-1beta levels with GI and PICF volume (P < 0.05). The correlations were stronger when the PICF levels were expressed as total IL-1beta amount and as total NE activity. The implants with inflamed gingiva (GI > 1) had higher levels of IL-1beta and NE activity than implants with noninflamed or slightly inflamed gingiva (GI <or= 1) (P < 0.05). Total NE activity in implants with deep pockets (PD > 3 mm) was greater than the implants with shallow pockets (PD <or= 3 mm) (P < 0.05). The implants of smoker patients had significantly lower PICF NE activity and IL-1beta levels, and significantly higher TNF-alpha levels than the implants of nonsmokers (P < 0.05). The findings of the present study indicate that NE activity and IL-1beta levels in PICF may be used to measure implant health status of patients who do not smoke.

The levels of serum vitamin C, malonyldialdehyde and erythrocyte reduced glutathione in chronic obstructive pulmonary disease and in healthy smokers

There is an increasing interest in the concept that oxidant/antioxidant imbalance plays a role in the pathogenesis of chronic obstructive pulmonary disease (COPD). However, most of the studies are concentrated on the local antioxidant/oxidant balance. In this study, we investigated the oxidant/antioxidant balance in systemic circulation of patients with COPD. Serum malonyldialdehyde (MDA), vitamin C and erythrocyte reduced glutathione (GSH) were determined in patients during acute exacerbation and during the stable phase of the disease, and compared with age- and sex-matched healthy controls. The levels of serum MDA, vitamin C and erythrocyte GSH were determined according to Yagi, Beutler and Bauer et al., respectively. Serum MDA levels were significantly higher in patients compared to controls, and during acute exacerbation compared to the stable phase. MDA levels in patients with acute exacerbation and in those in stable phase were also higher than in controls. We found significantly decreased levels of erythrocyte GSH and serum vitamin C in patients with acute exacerbation and stable COPD compared to controls. Although smoking caused an increase in oxidative stress in controls, the measured parameters were not affected by smoking in the patient group. In conclusion, there is a systemic oxidant/antioxidant imbalance in COPD, and this imbalance is probably independent of smoking.

Effects of selegiline (L-deprenyl) during smoking and short-term abstinence

RATIONALE

Changes in dopamine level are thought to play an important role in both smoking reward and withdrawal symptoms during abstinence. Medications that modulate dopamine levels may have beneficial effects on both withdrawal symptom levels and on response to smoking lapses during abstinence.

OBJECTIVES

To examine the effects of the selective MAO-B inhibitor selegiline on withdrawal symptoms, smoking behavior and smoking satisfaction ratings.

METHODS

Fifteen smokers received selegiline (10 mg/day) and placebo (in counterbalanced order) on Monday through Thursday of 2 study weeks, separated by a 2-week washout. During each study week, ad lib smoking sessions were scheduled to assess smoking behavior both before and after a brief period of abstinence. Subjective withdrawal symptoms and mood were measured daily, and a modified Stroop test sensitive to withdrawal was scheduled during the period of abstinence.

RESULTS

Selegiline decreased craving, especially during abstinence, and impaired performance on the modified Stroop test during subjects' attempts to abstain. Medication also reduced number of cigarettes smoked and smoking satisfaction ratings during the smoking sessions both before and after the brief abstinence attempt.

CONCLUSION

These results are consistent with an important role of dopamine in smoking behavior and abstinence. They suggest that pharmacological reduction of MAO-B levels during the early part of a quit attempt may aid in smoking cessation.

Expression of cell cycle proteins in head and neck cancer correlates with tumor site rather than tobacco use

Head and neck squamous cell carcinomas of non-smoking patients may result from specific defects in cell cycle control. Expression of p53, pRb, p16(INK4a) and Cyclin D1 was examined by immunohistochemistry of biopsies obtained from 24 non-smoking and 25 smoking patients, both groups representing similar clinical features (tumor site, stage of disease, gender). Expression of p16(INK4a) was restricted to carcinomas of the tonsils (8/24), P=0.0069. In 6/8 p16(INK4a)-positive cases, expression of pRb was absent or reduced. p16 was the only marker showing a significant correlation with a negative smoking history (P=0.0208). Overexpression of Cyclin D1 was frequent in carcinomas of the tongue (6/14) but rare in tonsillar carcinomas (2/24), P=0.0303. Expression of p53 was independent of the smoking history and the tumor site. Our results implicate that there are factors other than tobacco consumption which may influence the development of head and neck cancers at distinct tumor sites.