Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-8 (of 8 Records) |
Query Trace: Lawler TS[original query] |
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Associations between microbial communities and key chemical constituents in U.S. domestic moist snuff.
Tyxobert RE , Rivera AJ , Satten GA , Keong LM , Kuklenyik P , Lee GE , Lawler TS , Kimbrell JB , Stanfill SB , Valentin-Blasini L , Watson CH . PLoS One 2022 17 (5) e0267104 BACKGROUND: Smokeless tobacco (ST) products are widely used throughout the world and contribute to morbidity and mortality in users through an increased risk of cancers and oral diseases. Bacterial populations in ST contribute to taste, but their presence can also create carcinogenic, Tobacco-Specific N-nitrosamines (TSNAs). Previous studies of microbial communities in tobacco products lacked chemistry data (e.g. nicotine, TSNAs) to characterize the products and identify associations between carcinogen levels and taxonomic groups. This study uses statistical analysis to identify potential associations between microbial and chemical constituents in moist snuff products. METHODS: We quantitatively analyzed 38 smokeless tobacco products for TSNAs using liquid chromatography with tandem mass spectrometry (LC-MS/MS), and nicotine using gas chromatography with mass spectrometry (GC-MS). Moisture content determinations (by weight loss on drying), and pH measurements were also performed. We used 16S rRNA gene sequencing to characterize the microbial composition, and additionally measured total 16S bacterial counts using a quantitative PCR assay. RESULTS: Our findings link chemical constituents to their associated bacterial populations. We found core taxonomic groups often varied between manufacturers. When manufacturer and flavor were controlled for as confounding variables, the genus Lactobacillus was found to be positively associated with TSNAs. while the genera Enteractinococcus and Brevibacterium were negatively associated. Three genera (Corynebacterium, Brachybacterium, and Xanthomonas) were found to be negatively associated with nicotine concentrations. Associations were also investigated separately for products from each manufacturer. Products from one manufacturer had a positive association between TSNAs and bacteria in the genus Marinilactibacillus. Additionally, we found that TSNA levels in many products were lower compared with previously published chemical surveys. Finally, we observed consistent results when either relative or absolute abundance data were analyzed, while results from analyses of log-ratio-transformed abundances were divergent. |
Chemical analysis of snus products from the United States and northern Europe
Lawler TS , Stanfill SB , Tran HT , Lee GE , Chen PX , Kimbrell JB , Lisko JG , Fernandez C , Caudill SP , deCastro BR , Watson CH . PLoS One 2020 15 (1) e0227837 INTRODUCTION: Snus is an oral tobacco product that originated in Sweden. Snus products are available as fine-cut loose tobacco or in pre-portioned porous "pouches." Some snus products undergo tobacco pasteurization during manufacturing, a process that removes or reduces nitrite-forming microbes, resulting in less tobacco-specific nitrosamine content in the product. Some tobacco companies and researchers have suggested that snus is potentially less harmful than traditional tobacco and thus a potential smoking cessation aid or an alternative to continued cigarette consumption. Although snus is available in various countries, limited information exists on snus variants from different manufacturers. METHODS: Moisture, pH, nicotine, and tobacco-specific N'-nitrosamines (TSNAs) were quantified in 64 snus products made by 10 manufacturers in the United States and Northern Europe (NE). Reported means, standard errors, and differences are least-square (LS) estimates from bootstrapped mixed effects models, which accounted for correlation among repeated measurements. Minor alkaloids and select flavors were also measured. RESULTS: Among all product types, moisture (27.4%-59.5%), pH (pH 5.87-9.10), total nicotine (6.81-20.6 mg/g, wet), unprotonated nicotine (0.083-15.7 mg/g), and total TSNAs (390-4,910 ng/g) varied widely. The LS-mean unprotonated nicotine concentration of NE portion (7.72 mg/g, SE = 0.963) and NE loose (5.06 mg/g, SE = 1.26) snus were each significantly higher than US portion snus (1.00 mg/g, SE = 1.56). Concentrations of minor alkaloids varied most among products with the highest total nicotine levels. The LS-mean NNN+NNK were higher in snus sold in the US (1360 ng/g, SE = 207) than in NE (836 ng/g, SE = 132) countries. The most abundant flavor compounds detected were pulegone, eucalyptol, and menthol. CONCLUSION: Physical and chemical characteristics of US and NE products labeled as snus can vary considerably and should not be considered "equivalent". Our findings could inform public health and policy decisions pertaining to snus exposure and potential adverse health effects associated with snus. |
Chemical characterization of smokeless tobacco products from South Asia: Nicotine, unprotonated nicotine, tobacco-specific N-Nitrosamines, and flavor compounds
Stanfill SB , Croucher RE , Gupta PC , Lisko JG , Lawler TS , Kuklenyik P , Dahiya M , Duncan B , Kimbrell JB , Peuchen EH , Watson CH . Food Chem Toxicol 2018 118 626-634 Certain South Asian smokeless tobacco, including ready-to-use products, are not well characterized. | | • | In this study, we measured pH and concentrations of nicotine, tobacco-specific nitrosamines, and flavor compounds. | | • | Products had a wide range of moisture (4.0–46.6%), pH (pH 4.99–10.0), total nicotine (0.39–35.2 mg/g) and unprotonated nicotine (<0.01–11.9 mg/g). | | • | Two khaini products analyzed contained higher levels of N′-Nitrosonornicotine, a compound associated with oral cancer. | | • | Understanding the constituents in these products is necessary for characterizing potential harm as these products become more available worldwide. |
Surveillance of nicotine and pH in cigarette and cigar filler
Lawler TS , Stanfill SB , deCastro BR , Lisko JG , Duncan BW , Richter P , Watson CH . Tob Regul Sci 2017 3 101-116 OBJECTIVE: We examined differences between nicotine concentrations and pH in cigarette and cigar tobacco filler. METHODS: Nicotine and pH levels for 50 cigarette and 75 cigar brands were measured. Non-mentholated and mentholated cigarette products were included in the analysis along with several cigar types as identified by the manufacturer: large cigars, pipe tobacco cigars, cigarillos, mini cigarillos, and little cigars. RESULTS: There were significant differences found between pH and nicotine for cigarette and cigar tobacco products. Mean nicotine concentrations in cigarettes (19.2 mg/g) and large cigars (15.4 mg/g) were higher than the other cigars types, especially the pipe tobacco cigars (8.79 mg/g). The mean pH for cigarettes was pH 5.46. Large cigars had the highest mean pH value (pH 6.10) and pipe tobacco cigars had the lowest (pH 5.05). CONCLUSIONS: Although cigarettes are the most common combustible tobacco product used worldwide, cigar use remains popular. Our research provides a means to investigate the possibility of distinguishing the 2 tobacco product types and offers information on nicotine and pH across a wide range of cigarette and cigar varieties that may be beneficial to help establish tobacco policies and regulations across product types. |
Characterization of SPECTRUM variable nicotine research cigarettes
Richter P , Steven PR , Bravo R , Lisko JG , Damian M , Gonzalez-Jimenez N , Gray N , Keong LM , Kimbrell JB , Kuklenyik P , Lawler TS , Lee GE , Mendez M , Perez J , Smith S , Tran H , Tyx R , Watson CH . Tob Regul Sci 2016 2 (2) 94-105 OBJECTIVE: To provide researchers an extensive characterization of the SPECTRUM variable nicotine research cigarettes. METHODS: Data on cigarette physical properties, nicotine content, harmful and potentially harmful constituents in the tobacco filler was compiled. RESULTS: Data on physical properties, concentrations of menthol, nicotine and minor alkaloids, tobacco-specific nitrosamines, polycyclic aromatic hydrocarbons, ammonia, and toxic metals in the filler tobacco for all available varieties of Spectrum research cigarettes are provided. The similarity in the chemistry and physical properties of SPECTRUM cigarettes to commercial cigarettes renders them acceptable for use in behavioral studies. Baseline information on harmful and potentially harmful constituents in research tobacco products, particularly constituent levels such as minor alkaloids that fall outside typical ranges reported for commercial, provide researchers with the opportunity to monitor smoking behavior and to identify biomarkers that will inform efforts to understand the role of nicotine in creating and sustaining addiction. CONCLUSIONS: Well characterized research cigarettes suitable for human consumption are an important tool in clinical studies for investigating the physiological impacts of cigarettes delivering various levels of nicotine, the impact of reduced nicotine cigarettes on nicotine addiction, and the relationship between nicotine dose and smoking behavior. |
Comprehensive chemical characterization of rape tobacco products: nicotine, un-ionized nicotine, tobacco-specific n'-nitrosamines, polycyclic aromatic hydrocarbons, and flavor constituents
Stanfill SB , da Silva AL , Lisko JG , Lawler TS , Kuklenyik P , Tyx RE , Peuchen EH , Richter P , Watson CH . Food Chem Toxicol 2015 82 50-8 Rape, a diverse group of smokeless tobacco products indigenous to South America, is generally used as a nasal snuff and contains substantial amount of plant material with or without tobacco. Previously uncharacterized, rape contains addictive and harmful chemicals that may have public health implications for users. Here we report % moisture, pH and the levels of total nicotine, un-ionized nicotine, flavor-related compounds, tobacco-specific N-nitrosamines (TSNAs) and polycyclic aromatic hydrocarbons (PAHs) for manufactured and hand-made rape. Most rape products were mildly acidic (pH 5.17 - 6.23) with total nicotine ranging from 6.32 to 47.6 milligram per gram of sample (mg/g). Calculated un-ionized nicotine ranged from 0.03 to 18.5 mg/g with the highest values associated with hand-made rapes (pH 9.75 - 10.2), which contain alkaline ashes. In tobacco-containing rapes, minor alkaloid levels and Fourier transform infrared spectra were used to confirm the presence of Nicotiana rustica, a high nicotine tobacco species. There was a wide concentration range of TSNAs and PAHs among the rapes analyzed. Several TSNAs and PAHs identified in the products are known or probable carcinogens according to the International Agency for Research in Cancer. Milligram quantities of some non-tobacco constituents, such as camphor, coumarin, and eugenol, warrant additional evaluation. |
Chemical characterization of domestic oral tobacco products: total nicotine, pH, unprotonated nicotine and tobacco-specific N-nitrosamines
Lawler TS , Stanfill SB , Zhang L , Ashley DL , Watson CH . Food Chem Toxicol 2013 57 380-6 In the United States, moist snuff has been studied more widely than other distinct categories of oral tobacco. In this study, we measured pH, moisture, nicotine (total and unprotonated), and tobacco-specific N-nitrosamines (TSNAs) for other established (twist, loose leaf, plug, and dry snuff without pouch) and emerging oral tobacco products (dry snuff pouch, US-made snus, and dissolvable tobacco). Among the seven product categories, product pH ranged from 4.7 to 7.9, and total nicotine concentration spanned from 3.9 to 40.1mg/g. The most readily absorbable form of nicotine (unprotonated nicotine) varied more than 350-fold, ranging from 0.01 to 3.7mg/g. While the highest total nicotine concentrations were observed in twist products, snus and dissolvable tobacco had the highest unprotonated nicotine levels. Among all products, total TSNA concentrations ranged from 313 to 76,500ng/g with dry snuff having the highest total TSNA concentrations. This study demonstrates the diversity among oral tobacco products and highlights the potential of these products to deliver a wide range of nicotine and carcinogenic TSNAs. Characterizing the chemical content of these products may be helpful in further understanding the risk of marketing these products to oral tobacco users and smokers as an alternative and discrete form of tobacco. |
Global surveillance of oral tobacco products: total nicotine, unionised nicotine and tobacco-specific N-nitrosamines
Stanfill SB , Connolly GN , Zhang L , Jia LT , Henningfield JE , Richter P , Lawler TS , Ayo-Yusuf OA , Ashley DL , Watson CH . Tob Control 2010 20 (3) e2 OBJECTIVE: Oral tobacco products contain nicotine and carcinogenic tobacco-specific N-nitrosamines (TSNAs) that can be absorbed through the oral mucosa. The aim of this study was to determine typical pH ranges and concentrations of total nicotine, unionised nicotine (the most readily absorbed form) and five TSNAs in selected oral tobacco products distributed globally. METHODS: A total of 53 oral tobacco products from 5 World Health Organisation (WHO) regions were analysed for total nicotine and TSNAs, including 4-(methyl-nitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), using gas chromatography or liquid chromatography with mass spectrometric detection. Unionised nicotine concentrations were calculated using product pH and total nicotine concentrations. Fourier transform infrared spectroscopy was used to help categorise or characterise some products. RESULTS: Total nicotine content varied from 0.16 to 34.1 mg/g product, whereas, the calculated unionised nicotine ranged from 0.05 to 31.0 mg/g product; a 620-fold range of variation. Products ranged from pH 5.2 to 10.1, which translates to 0.2% to 99.1% of nicotine being in the unionised form. Some products have very high pH and correspondingly high unionised nicotine (eg, gul powder, chimo, toombak) and/or high TSNA (eg, toombak, zarda, khaini) concentrations. The concentrations of TSNAs spanned five orders of magnitude with concentrations of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) ranging from 4.5 to 516 000 ng/g product. CONCLUSIONS: These data have important implications for risk assessment because they show that very different exposure risks may be posed through the use of these chemically diverse oral tobacco products. Because of the wide chemical variation, oral tobacco products should not be categorised together when considering the public health implications of their use. |
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