Maternal cigarette smoking, metabolic gene polymorphism, and infant birth weight

CONTEXT

Little is known about genetic susceptibility to cigarette smoke in relation to adverse pregnancy outcomes.

OBJECTIVE

To investigate whether the association between maternal cigarette smoking and infant birth weight differs by polymorphisms of 2 maternal metabolic genes: CYP1A1 and GSTT1.

DESIGN, SETTING, AND PARTICIPANTS

Case-control study conducted in 1998-2000 among 741 mothers (174 ever smokers and 567 never smokers) who delivered singleton live births at Boston Medical Center. A total of 207 cases were preterm or low-birth-weight infants and 534 were non-low-birth-weight, full-term infants (control).

MAIN OUTCOME MEASURE

Birth weight, gestation, fetal growth by smoking status and CYP1A1 MspI (AA vs Aa and aa, where Aa and aa were combined because of small numbers of aa and similar results), and GSTT1 (present vs absent) genotypes.

RESULTS

Without consideration of genotype, continuous maternal smoking during pregnancy was associated with a mean reduction of 377 g (SE, 89 g) in birth weight (odds ratio [OR], 2.1; 95% confidence interval [CI], 1.2-3.7). When CYP1A1 genotype was considered, the estimated reduction in birth weight was 252 g (SE, 111 g) for the AA genotype group (n = 75; OR, 1.3; 95% CI, 0.6-2.6), but was 520 g (SE, 124 g) for the Aa/aa genotype group (n = 43 for Aa, n = 6 for aa; OR, 3.2; 95% CI, 1.6-6.4). When GSTT1 genotype was considered, the estimated reduction in birth weight was 285 g (SE, 99 g) (OR, 1.7; 95% CI, 0.9-3.2) and 642 g (SE, 154 g) (OR, 3.5; 95% CI, 1.5-8.3) for the present and absent genotype groups, respectively. When both CYP1A1 and GSTT1 genotypes were considered, the greatest reduction in birth weight was found among smoking mothers with the CYP1A1 Aa/aa and GSTT1 absent genotypes (-1285 g; SE, 234 g; P<.001). Among never smokers, genotype did not independently confer an adverse effect. A similar pattern emerged in analyses stratified by maternal ethnicity and in analyses for gestation.

CONCLUSIONS

In our study, maternal CYP1A1 and GSTT1 genotypes modified the association between maternal cigarette smoking and infant birth weight, suggesting an interaction between metabolic genes and cigarette smoking.

Lipid peroxidation and glutathione peroxidase activity in chronic obstructive pulmonary disease exacerbation: prognostic value of malondialdehyde

Results of recent studies have indicated that during exacerbation of chronic obstructive pulmonary disease (COPD), antioxidant capacity is lower and the levels of lipid peroxidation products are higher than those in age-matched healthy subjects. The aim of this study was to assess the time course of changes in oxidant stress during the treatment of exacerbation of COPD. For this purpose, we measured erythrocyte glutathione peroxidase (GPx) activity and serum levels of the lipid peroxidation product malondialdehyde (MDA) in 18 male patients with acute exacerbation of COPD. Fifteen healthy non-smokers having no history of lung disease served as control subjects. Mean erythrocyte GPx values of patients were 45.54 +/- 9.04 u/gHb on admission and had increased to 72.77 +/- 9.68 by the tenth day of treatment, but still remained lower than those of healthy subjects (83.13 +/- 10.91) (p=0.007). Serum MDA values in patients were Vol. 12, No. 1, 2001 significantly higher (2.68 +/- 1.28 nmol/ml) than those in control subjects (1.04 +/- 0.36 nmol/ml) (p=0.000) and returned to normal values by the tenth day of treatment (1.08 +/- 0.36 nmol/ml) (p=0.766). Erythrocyte GPx values in patients who were current smokers (39.87 +/- 3.82 u/gHb) were lower than those in ex-smokers (49.15 +/- 9.67 u/gHb) (p=0.021). Moreover, serum MDA values in patients who were current smokers (3.32 +/- 1.18 nmol/ml) were higher than those in ex-smokers (1.66 +/- 0.60 nmol/ml) (p=0.007). The results show that oxidative stress in patients with acute exacerbation of COPD is related to higher MDA levels that return to normal conditions during the course of treatment. In conclusion, the results suggest that MDA levels can serve as a marker of prognosis and of the success of treatment of the exacerbation of COPD.

Extended NO analysis applied to patients with COPD, allergic asthma and allergic rhinitis

The recommended method to measure exhaled nitric oxide (NO) cannot reveal the source of NO production. We applied a model based on the classical Fick's first law of diffusion to partition NO in the lungs. The aim was to develop a simple and robust solution algorithm with a data quality control feature, and apply it to patients with known alterations in exhaled NO. Subjects with allergic rhinitis, allergic asthma, chronic obstructive pulmonary disease (COPD) smokers and controls were investigated. NO was measured at three expiratory flow rates. An iteration method was developed to partition NO. The airway tissue content of NO was increased in asthma, 144 +/- 80 ppb (P = 0.04) and decreased in smokers, 56 +/- 36 ppb (P = 0.02). There was no difference between subjects with rhinitis, 98 +/- 40 ppb and controls, 98 +/- 44 ppb. The airway transfer rate was increased in allergic asthma and allergic rhinitis, 12 +/- 4 vs. 12 +/- 5 ml sec(-1), compared to controls, 8 +/- 2 ml sec(-1) (P < 0.001). The alveolar levels were no different from controls, 2 +/- 1 ppb. In COPD the alveolar levels were increased, 4 +/- 2 ppb (P < 0.001). Extended NO analysis reveals from where in the respiratory system NO is generated. Hence, this new test can be added to the tools the physician has for the diagnosis and treatment of patients with respiratory disorders.

Mechanism of cigarette smoke condensate-induced acute inflammatory response in human bronchial epithelial cells

BACKGROUND

To demonstrate the involvement of tobacco smoking in the pathophysiology of lung disease, the responses of pulmonary epithelial cells to cigarette smoke condensate (CSC) - the particulate fraction of tobacco smoke - were examined.

METHODS

The human alveolar epithelial cell line A549 and normal human bronchial epithelial cells (NHBEs) were exposed to 0.4 microg/ml CSC, a concentration that resulted in >90% cell survival and <5% apoptosis. Changes in gene expression and signaling responses were determined by RT-PCR, western blotting and immunocytofluorescence.

RESULTS

NHBEs exposed to CSC showed increased expression of the inflammatory mediators sICAM-1, IL-1beta, IL-8 and GM-CSF, as determined by RT-PCR. CSC-induced IL-1beta expression was reduced by PD98059, a blocker of mitogen-actived protein kinase (MAPK) kinase (MEK), and by PDTC, a NFkappaB inhibitor. Analysis of intracellular signaling pathways, using antibodies specific for phosphorylated MAPKs (extracellular signal-regulated kinase [ERK]-1/2), demonstrated an increased level of phosphorylated ERK1/2 with increasing CSC concentration. Nuclear localization of phosphorylated ERK1/2 was seen within 30 min of CSC exposure and was inhibited by PD98059. Increased phosphorylation and nuclear translocation of IkappaB was also seen after CSC exposure. A549 cells transfected with a luciferase reporter plasmid containing a NFkappaB-inducible promoter sequence and exposed to CSC (0.4 microg/ml) or TNF-alpha (50 ng/ml) had an increased reporter activity of approximately 2-fold for CSC and 3.5-fold for TNF-alpha relative to untreated controls.

CONCLUSION

The acute phase response of NHBEs to cigarette smoke involves activation of both MAPK and NFkappaB.

Effects of aldehyde dehydrogenase-2 genetic polymorphisms on metabolism of structurally different aldehydes in human liver

Genotype analysis of the aldehyde dehydrogenase (ALDH)-2 gene was performed using an improved simplified method, and effects of the genotype on the metabolism of a variety of aldehydes in different fractions of human liver cells were investigated. The effects of sex, aging, smoking, drinking alcohol, liver function, and various drugs on ALDH activity were also analyzed. Of the 39 subjects, eight were heterozygotes of the wild (ALDH2*1) and mutant (ALDH2*2) alleles, and the others were homozygotes of the wild allele. ALDH activity toward acetaldehyde in liver mitochondria from subjects with a mutant allele was less than 10% of that with two alleles of wild-type, and the activities toward formaldehyde, propionaldehyde, n-butyraldehyde, capronaldehyde, and heptaldehyde were also significantly lower in the ALDH2*1/*2 rather than ALDH2*1/*1 group. However, the metabolism of octylaldehyde, decylaldehyde, retinaldehyde, benzaldehyde, 3-hydroxybenzaldehyde, and 2,5-dihydroxybenzaldehyde was similar in the two genotypes. Changes in activity in the cytosolic fraction were similar to those in mitochondria. There was no significant difference in ALDH activity in microsomes between the two groups. Total activities of ALDH toward acetaldehyde and other short-chain aliphatic aldehydes in supernatant fractions of homogenized liver were affected in a manner similar to that in mitochondria. Our results suggest that the single nucleotide polymorphisms of the ALDH2 gene only alter the metabolism of aldehydes with a short aliphatic chain. Furthermore, sex, drinking alcohol, and smoking had little effect on ALDH activity, although the activity in elderly individuals tended to be lower albeit statistically insignificant.

Association between bone loss in periodontal disease and polymorphism of N-acetyltransferase (NAT2)

BACKGROUND

The individual susceptibility to periodontal disease is probably the result of an interaction of multiple genetic and environmental influences. Polymorphism of the N-acetyltransferase (NAT 2) modifies the individual susceptibility to toxicity from certain therapeutic drugs or heterocyclic amines including substances from cigarette smoke. Subjects are to be classified as 'slow' or 'rapid' acetylators according to how fast their bodies metabolise such xenobiotics. Differences in their ability to detoxify these substances may contribute to an increased risk for periodontitis in subjects exposed to cigarette smoke or other xenobiotics.

OBJECTIVE

The purpose of this study was to assess whether the NAT2 genotype is a risk factor for periodontal disease in Caucasian patients suffering from adult periodontitis.

MATERIAL AND METHODS

154 Caucasian subjects were assigned to one of the 3 groups: no, moderate, and severe periodontal disease based on bone and attachment loss. In all subjects, genotyping for mutations on the N-acetyltransferase (NAT2) gene was performed by means of PCR and RFLP analysis.

RESULTS

Comparison of frequency distribution of NAT2 acetylation types between the most diseased group and not or moderately affected subjects showed a tendency to over-representation of slow acetylators with severe disease. When using bone loss as measure of periodontitis, this over-representation shows a significant association with the disease (odds ratio=2.13, p=0.025). In the logistic regression analysis, adjusted for age and smoking, NAT2 slow phenotype was significantly associated with the severity of bone loss, the odds ratio being 2.09 (95% C.I. 1.02-4.26, p=0.043). In a case-control analysis (controlled for smoking, gender and age) mean bone loss showed a significant difference between the 2 NAT2-type groups (Mann-Whitney test p=0.041).

CONCLUSION

The data suggest that the slow acetylator phenotype may be associated with a higher risk of periodontitis, especially in smokers. Possible explanations regarding the mechanism are discussed; however, such attempts are highly speculative at this time.

Quantitative analysis of substance P, neurokinin A and calcitonin gene-related peptide in pulp tissue from painful and healthy human teeth

AIM

The purpose of this study was to investigate the levels of substance P (SP), neurokinin A (NKA) and calcitonin gene-related peptide (CGRP) in painful and healthy human dental pulps.

METHODOLOGY

Forty-six samples of pulp tissue were collected from extracted or endodontically treated painful teeth and 20 from clinically healthy teeth extracted for orthodontic reasons. All pulp samples were boiled in 0.5 m acetic acid for 10 min, centrifuged and the supernatant collected. SP, NKA and CGRP levels were measured using radioimmunoassay.

RESULTS

Substance P and CGRP were present in all samples and NKA was detected in 96% of the pulps. CGRP was present in much higher concentrations than SP and NKA in both painful and non-painful teeth. The painful teeth had significantly higher concentrations of SP (P = 0.02), NKA (P < 0.001) and CGRP (P = 0.03) than non-painful teeth. The concentration of CGRP was significantly higher in the pulps of smokers compared with non-smokers (P = 0.02).

CONCLUSIONS

Elevated levels of these neuropeptides in pulps from painful teeth indicate that they may play an important role in the process of pulpal inflammation and pain. Further investigation of the association between these neuropeptides and pulpal status may help to improve our understanding of pulpal inflammation and dental pain.

Liver protein synthesis in physiology and in disease states

Liver protein synthesis is usually estimated in humans by measuring the synthesis rates of major exported liver proteins. Among these, the synthesis rates of albumin and fibrinogen have been more commonly studied. Recently, it was reported that several physiological stimuli such as physical exercise followed by recovery in the upright position, active and passive ascent to high altitude or life-style habits like vegetarian diet or smoking affect the synthesis rates of albumin and fibrinogen. Among disease states, the most recent literature addresses the effects of kidney diseases (hemodialysis, nephrotic syndrome), type 2 diabetes mellitus and growth hormone administration to critically ill patients and to patients undergoing laparoscopic colecystectomy. The results of these studies have clarified several aspects of the regulation of liver protein synthesis in humans and raise open questions that will stimulate the future research in the area.

Newly identified proteins in human nasal lavage fluid from non-smokers and smokers using two-dimensional gel electrophoresis and peptide mass fingerprinting

Human nasal lavage fluids (NLFs) were analyzed with two-dimensional gel electrophoresis (2-DE) and proteins were identified with peptide mass fingerprinting using matrix-assisted laser desoption/ionization time of flight mass spectrometry. In some cases, the identification was verified by analysis of post-source decay fragmentation spectra. Many of the identified proteins were new forms or fragments of previously found proteins (e.g. albumin, lactoferrin, cystatin, calgranulin, von Ebners gland protein and palate lung nasal epithelium clone), while others were proteins that have previously been indicated by 2-DE image matching or immunoblots (e.g. apolipoprotein AI, lysozyme C, and Clara cell secretory protein). Some new proteins, not shown before in 2-DE patterns of NLF were also found, e.g. mammaglobin B, (2)-microglobulin and immunoglobulin J chain. Of the identified NLF proteins many appear to be involved in inflammatory and immune responses. A study was therefore conducted to investigate if the levels of these proteins were changed in smokers compared to nonsmokers. It was found that NLF from smokers contained decreased levels of Clara cell secretory protein, and increased proportions of a truncated variant of lipocortin-1, three acidic forms of alpha(1)-antitrypsin, and one phosphorylated form of cystatin S. Furthermore, NLF from smokers contained increased proportions of a new variant of palate lung nasal epithelium clone (PLUNC), a recently identified airway irritation marker. The results demonstrate that 2-DE of NLF may be used to assess alterations of proteins or post-translationally modified proteins in smokers. Clara cell secretory protein (CC 16, CC 10) and lipocortin-1 are two anti-inflammatory, phospholipase A(2) inhibitory proteins, and alpha(1)-antitrypsin and cystatin S are two proteinase inhibitors. Changed levels of these proteins may therefore be of importance to the airway inflammation caused by smoking. The results also support the notion that PLUNC is involved in inflammatory responses in the upper airways.

Clara cell protein (CC16) in serum and bronchoalveolar lavage fluid of subjects exposed to asbestos

The Clara cell protein (CC16) is a small and readily diffusible protein of 16 kDa secreted by bronchiolar Clara cells in the distal airspaces. These epithelial cells are altered in several pulmonary pathological processes induced by various lung toxicants. In the search for a new biomarker of asbestos-induced lung impairment, we used a sensitive immunoassay to determine the levels of CC16 in bronchoalveolar fluid (BALF) and serum of subjects exposed to asbestos compared with a group of healthy controls. In the BALF of asbestos-exposed subjects there was an insignificant trend towards CC16 elevation compared with controls, with a (mean +/- SD of 0.81 +/- 0.65 mg l-1 for asbestos-exposed subjects (n = 23) versus 0.39 +/- 0.19 mg l-1 for controls (n = 11) (p = 0.09). In serum, CC16 concentration was significantly increased among asbestos-exposed subjects, with values of 27.2 +/- 24.0 micrograms l-1 for asbestos-exposed subjects (n = 34) versus 16.1 +/- 7.6 micrograms l-1 for controls (n = 34) (p = 0.01). Regarding the effects of smoking, there were significant differences between generally lower CC16 levels in serum and BALF (p = 0.05 and 0.001, respectively) of smokers compared with the higher levels in non-smokers. Serum CC16 levels positively correlated with those in BALF, which is consistent with a diffusional transfer of CC16 from the bronchoalveolar space into the serum. No association, however, emerged between the levels of CC16 in serum or BALF and either the duration of asbestos exposure or the severity of the lung impairment as assessed by chest X-ray. These findings suggest that exposure to asbestos elicits early changes in the local and, importantly, also the systemic levels of CC16. This pneumoprotein therefore appears as a promising non-invasive biomarker of asbestos-induced lung injury and occupational disease in both smoking and non-smoking exposed subjects.

Relationships between intestinal calcium absorption, serum vitamin D metabolites and smoking in postmenopausal women

Smoking has been associated with low bone density, fractures and poor intestinal calcium absorption. Calcium absorption is a critical factor in calcium balance in postmenopausal women but the mechanisms causing decreased absorption efficiency in postmenopausal smokers are controversial and poorly defined. We performed a cross-sectional study of 405 postmenopausal women attending a clinic for the management of osteoporosis to compare intestinal calcium absorption efficiency, serum vitamin D metabolites and parathyroid hormone levels in postmenopausal women who had never smoked, who were smokers previously or who were current smokers, to examine the relationships between these variables in smokers. Two hundred and fifty-two of the women had never smoked, 79 had smoked previously and 74 were current smokers. The hourly fractional rate of calcium absorption was similar in non-smokers and those who had previously smoked. Radiocalcium absorption was less in the 74 smokers compared with the 331 non-smokers [0.60 (0.29 SD) vs 0.71 (0.27); p = 0.004], as were serum calcitriol (p<0.001) and parathyroid hormone (PTH) (p<0.01). There was no difference in the relationship between calcium absorption and serum calcitriol between smokers (r = 0.38) and non-smokers (r = 0.28); hence the impaired calcium absorption in the smokers was almost entirely attributable to suppression of the PTH-calcitriol endocrine axis. In postmenopausal women smoking is associated with a reduction in calcium absorption efficiency due to suppression of the PTH-calcitriol axis. This impairment of calcium absorption could lead to accelerated bone loss and limit the usefulness of dietary calcium supplementation.

Cigarette smoke-induced lipid peroxidation in human skin and its inhibition by topically applied antioxidants

Cigarette smoke, whether indirect or direct stream, is an environmental pollutant which presents an increasing health problem. In order to determine damage to human skin at the biochemical level, volar forearms were exposed to cigarette smoke for fifteen minutes and then assayed for the presence of stratum corneum lipid peroxides. A time-dependent increase was observed over a 24-hour post-exposure period. At 24 h, the average baseline level of lipid peroxides was 14.9 nmol/unit area of skin as compared to 32.0 nmol/unit area of skin for the smoke-exposed arms. In addition, when topical antioxidants were pre-applied to the skin and then exposed to cigarette smoke, an average decrease of 40.9% in lipid peroxide values was observed. These data demonstrate that peroxidation was induced in human skin by cigarette smoke and subsequently inhibited by the presence of antioxidants.

[Effect of smoking on PaO2 at rest and during moderate exercise]

The most data on smoker's arterial oxygen tension (PaO2) were carried out at rest and from non arterial blood sample. The aim of this retrospective study was to compare smokers and nonsmoker's arterial oxygen tension (PaO2) at rest and during a moderate exercise. 98 male smokers between 23 and 69 years old and 98 male nonsmokers with the same age bracket were recruited among subjects submitted to arterial blood gas analysis according to the following protocol: 2 arterial blood samples were taken at rest, with an interval of 5 minutes, followed by a third one taken at the end of a moderate effort (50 watts during 5 minutes) on a bicycle in the supine position. Wilcoxon's test was used to compare the measured biological parameters between smokers and nonsmokers. Unlike nonsmokers, smoker's PaO2 increased meaning fully during moderate exercise. However, like at rest, it remained lower than nonsmoker's PaO2.: 87.6 +/- 15.8 mmHg Versus 94.1 +/- 10.4 mmHg (p < 0.0001). These beneficial effects of exercise on smoker's PaO2, although limited among heavy smokers group, suggested that hypoxia observed at rest must be due to troubles in ventilation/perfusion ratio in the lungs. In comparison to nonsmokers, the most significantly hypoxia was founded in smokers between 40 and 59 years old. The variation of PaO2 in nonsmokers was normal in comparison with age, but strongly disturbed in smokers at rest as well as during a moderate exercise, despite the lack of correlation between PaO2 and the intensity of tobacco consumption (expressed as number of pack-years). Thus, the smokers' PaO2 deterioration concerned together its value and its variation in comparison with age.

Immunohistochemical detection of malondialdehyde-DNA adducts in human oral mucosa cells

Malondialdehyde (MDA) is a major lipid peroxidation product that is mutagenic and tumorigenic. MDA-modified DNA adducts have been detected in animal and human tissues and may be a marker of human cancer risk. An immunohistochemical method, using a previously generated monoclonal antibody specific for MDA-DNA adducts, has been developed for the detection and quantification of DNA damage in human oral mucosa cells. The method was used initially on woodchuck liver cells treated with and without MDA, and then applied to the detection of adducts in oral mucosa cells of smokers and non-smokers. Levels of DNA damage were elevated in 25 smokers (mean relative staining intensity 97 +/- 41) compared with 25 age-, race- and sex-matched non-smokers (74 +/- 17, P < 0.02). These results demonstrate that MDA-DNA adducts can be measured in single cells of human samples by an immunohistochemical method. This methodology provides a simple way to monitor MDA-DNA damage and should be useful for studies investigating the role of exogenous and endogenous agents in oxidative stress and carcinogenesis.

Interleukin-4 and interleukin-5 gene expression and inflammation in the mucus-secreting glands and subepithelial tissue of smokers with chronic bronchitis. Lack of relationship with CD8(+) cells

We wished to determine if the inflammatory cells surrounding the airway mucus-secreting glands in chronic bronchitis (CB) were associated with interleukin (IL)-4 and IL-5 mRNA expression and whether the CD8 T cell population expressed these cytokines. Digoxigenin-labeled IL-4 and IL-5 antisense RNA probes were used to detect gene expression in 11 asymptomic smokers (AS), 11 smokers with CB alone with normal lung function, and 10 smokers with chronic bronchitis and coexisting chronic obstructive pulmonary disease (CB+COPD; FEV(1)% of predicted of 43-77% and FEV(1)/ FVC of 51-68%). There were approximately three times as many IL-4 than IL-5 mRNA(+) cells. The highest number of IL-4 mRNA(+) cells were in the submucosal glands of the CB group with normal lung function (216/mm(2)), significantly higher than the values in either the AS (63/mm(2)) or the CB+COPD (87/mm(2)) groups, respectively (p < 0.01). There were similar group differences when the total numbers of inflammatory cells were compared. Accordingly, there was a positive correlation between the number of IL-4 mRNA(+) cells and the total number of inflammatory cells in both the subepithelium and glandular compartments (r = 0.60; p = 0.01 and r = 0.70; p = 0.02, respectively). There were no significant associations between the numbers of CD8(+) and IL-4 or IL-5 mRNA(+) cells. Of 1328 IL-4(+) and 1404 CD8(+) cells counted none was double labeled. Of 727 IL-5(+) and 1569 CD8(+) cells, none was double labeled. In contrast, as a positive control, 34% of tumor necrosis factor (TNF)-alpha(+) cells were also CD8(+) and 15% of CD8(+) cells were TNF-alpha positive. Thus, cells other than the CD8(+) phenotype produce IL-4 and IL-5 in CB. We conclude that there is increased inflammation and IL-4 gene expression in the mucus-secreting glands and the airway mucosa of smokers with bronchitis: both are lower in those with CB and coexisting COPD suggesting that airway inflammation in CB is reduced when airway obstruction develops.

Endogenous nicotinic cholinergic activity regulates dopamine release in the striatum

Dopamine is vital for coordinated motion and for association learning linked to behavioral reinforcement. Here we show that the precise overlap of striatal dopaminergic and cholinergic fibers underlies potent control of dopamine release by ongoing nicotinic receptor activity. In mouse striatal slices, nicotinic antagonists or depletion of endogenous acetylcholine decreased evoked dopamine release by 90%. Nicotine at the concentration experienced by smokers also regulated dopamine release. In mutant mice lacking the beta2 nicotinic subunit, evoked dopamine release was dramatically suppressed, and those mice did not show cholinergic regulation of dopamine release. The results offer new perspectives when considering nicotine addiction and the high prevalence of smoking in schizophrenics.

Development of Bowman-Birk inhibitor for chemoprevention of oral head and neck cancer

Leukoplakia in the oral cavity has been used as a putative surrogate marker of head and neck cancer development. A class of chemoprevention compounds, called protease inhibitors, has been shown in vitro and in animal models to effectively suppress premalignant lesions. Bowman-Birk inhibitor (BBI) is a protease inhibitor derived from soybeans that has demonstrated chemoprevention activity in many in vitro and animal systems, including the hamster cheek pouch model. Pilot, Phase I and Phase IIa studies of Bowman-Birk Inhibitor in patients with oral leukoplakia have demonstrated no detectable side effects. In the Phase IIa trial, changes in the protease activity in oral mucosal cells after BBI Concentratec (BBIC) treatment correlated with the changes in neu protein levels. Additionally, evidence for a dose-related treatment effect of BBIC on oral leukoplakia was demonstrated. These results indicate that BBIC should be investigated for chemopreventive activity in a randomized clinical trial.

[Relationship between the fecal mutagenicity and metal content, smoking habit and dietary intake]

OBJECTIVE

The study was carried out to collect basic data on exposure of mucous cells of the large intestine to mutagens by investigating the genotoxicity of fecal samples from the urban population. Simultaneously, relations with food intake (food groups and nutritive components), lifestyle factors and fecal metal content was investigated.

METHODS

A total of 199 self-collected fecal samples from middle aged healthy volunteer living in urban areas of Osaka city were freeze-dried and ground in a mill. The mutagenicity of aqueous extracts of the ground samples was measured by the umu-test. Metal content of the feces was analysed by atomic absorption spectrophotometlly. On the day previous to the feces collection, the contents of meals were recorded and confirmed by interview with a dietitian. Quantification of nutritive components was carried out using the 4th edition of the Japan Food Standard Vomposition Table.

RESULTS

Mutagenicity of feces was higher in males than in females, and in those aged 40-49 years than 50-69 years in males but not females. Large differences were found for content of 8 metals in the feces; concentrations were in the decreasing order of calcium, potassium, magnesium, sodium, zinc, iron, manganese and copper, the highest being 20.4 mg for calcium and the lowest was 53.5 micrograms for copper. Between the metal contents and mutagenicity, values for zinc and iron showed positive correlations and for sodium a negative correlation under S9(+) conditions. A weak but significant correlation was observed between the numbers of cigarettes smoked per day and S9 (+) mutagenicity. However we could not find any relation with food groups or nutritive components.

CONCLUSION

It is well known that human feces contain many mutagens and carcinogens and that these can act directly on the mucous membrane of large intestine. Therefore, it is very important to estimate exposure levels. From the present data we can conclude that relations between mutation-activity of the feces and diet are complex. Their elucidation will require a large number of volunteers who have similar living conditions to obtain appropriate data.

Effect of smoking on single dose pharmacokinetics of phenobarbital

In order to determine interaction of smoking with single dose pharmacokinetics of phenobarbital, a 60 mg tablet of the drug was given to 12 healthy male subjects in two groups (6 smokers and 6 non-smokers) in a double blind study. An HPLC method using UV detection was developed to assess phenobarbital in plasma of the subjects. Pharmacokinetic parameters were calculated and compared in the two groups. Pharmacokinetic parameters of the two groups were not significantly different in the two groups (p<0.05). The results show no considerable effect of cigarette smoking on phenobarbital pharmacokinetics, which is in agreement with enzyme studies performed previously.

Smoking and mental illness

Patients with mental illness have a higher incidence of smoking than the general population and are the major consumers of tobacco products. This population includes subjects with schizophrenia, manic depression, depression, posttraumatic stress disorder (PTSD), attention-deficit disorder (ADD), and several other less common diseases. Smoking cessation treatment in this group of patients is difficult, often leading to profound depression. Several recent findings suggest that increased smoking in the mentally ill may have an underlying biological etiology. The mental illness schizophrenia has been most thoroughly studied in this regard. Nicotine administration normalizes several sensory-processing deficits seen in this disease. Animal models of sensory deficits have been used to identify specific nicotinic receptor subunits that are involved in these brain pathways, indicating that the alpha 7 nicotinic receptor subunit may play a role. Genetic linkage in schizophrenic families also supports a role for the alpha 7 subunit with linkage at the alpha 7 locus on chromosome 15. Bipolar disorder has some phenotypes in common with schizophrenia and also exhibits genetic linkage to the alpha 7 locus, suggesting that these two disorders may share a gene defect. The alpha 7 receptor is decreased in expression in schizophrenia. [(3)H]-Nicotine binding studies in postmortem brain indicate that high-affinity nicotinic receptors may also be affected in schizophrenia.

Urinary thioether excretion and erythrocyte glutathione S-transferase activities in smokers and patients with squamous-cell laryngeal cancer

Various biomarkers exist for assessment of exposure to cigarette smoke. The aim of this study is to evaluate whether the urinary thioethers (UT) and erythrocyte glutathione S-transferase (GST) enzyme activities can be used as a biomarker or indicator of a higher risk of laryngeal cancer among smokers. In the present study, the concentration of UT and erythrocyte CST activities were measured in a sample of 84 subjects: controls, smokers, and smokers with squamous-cell carcinoma of the larynx (SLC). For this study, cases were restricted to men, since the number of women was not sufficient for statistical comparisons. Smoking significantly increased UT levels without a marked change in GST activity. However, in SLC smoking patients both UT levels and GST activity were significantly elevated. The use of nonspecific UT levels with GST activity determination seems to be a reliable indicator for the presence of laryngeal cancer in smokers.

Augmented oxidative stress of platelets in chronic smokers. Mechanisms of impaired platelet-derived nitric oxide bioactivity and augmented platelet aggregability

OBJECTIVES

We investigated whether impaired platelet-derived nitric oxide (PDNO) bioactivity and augmented platelet aggregability in chronic smokers are related to the imbalance of the intraplatelet redox state through increased oxidative stress.

BACKGROUND

Chronic smoking impairs PDNO release and augments platelet aggregability. However, their mechanisms are unknown.

METHODS

Collagen-induced PDNO release, platelet aggregation, plasma and intraplatelet vitamin C and reduced glutathione (GSH), intraplatelet cyclic guanosine 3',5'-monophosphate (cGMP) and intraplatelet nitrotyrosine production, which is a marker of the peroxynitrite formation, were measured in 11 chronic smokers and 10 age-matched nonsmokers.

RESULTS

Release of PDNO and levels of intraplatelet cGMP were lower, and platelet aggregation was greater, in smokers than in nonsmokers. Intraplatelet vitamin C and GSH levels were lower in smokers than in nonsmokers. Intraplatelet nitrotyrosine production was greater in smokers than in nonsmokers. Next, we investigated the effects of oral vitamin C administration (2 g). After vitamin C administration, intraplatelet vitamin C levels were increased and not different at 2 h between the two groups. Then, PDNO release, intraplatelet cGMP levels and platelet aggregation in smokers were restored to the levels of nonsmokers. In smokers, PDNO release and consumption of GSH during platelet aggregation were inversely correlated, and consumption was much less after vitamin C administration. Vitamin C administration decreased intraplatelet nitrotyrosine production in smokers.

CONCLUSIONS

Impaired PDNO bioactivity and augmented platelet aggregability may be caused by an imbalance of the intraplatelet redox state through increased oxidative stress in smokers.