David L. Ashley

Botulinum Neurotoxin Detection and Differentiation by Mass Spectrometry

A new rapid, mass spectrometry-based method to detect and differentiate botulinal neurotoxins is described.

Assessing secondhand smoke using biological markers

Secondhand smoke exposure (SHSe) is a known cause of many adverse health effects in adults and children. Increasingly, SHSe assessment is an element of tobacco control research and implementation worldwide. In spite of decades of development of approaches to assess SHSe, there are still unresolved methodological issues; therefore, a multidisciplinary expert meeting was held to catalogue the approaches to assess SHSe and with the goal of providing a set of uniform methods for future use by investigators and thereby facilitate comparisons of findings across studies. The meeting, held at Johns Hopkins, in Baltimore, Maryland, USA, was supported by the Flight Attendant Medical Research Institute (FAMRI). A series of articles were developed to summarise what is known about self-reported, environmental and biological SHSe measurements. Non-smokers inhale toxicants in SHS, which are mainly products of combustion of organic materials and are not specific to tobacco smoke exposure. Biomarkers specific to SHSe are nicotine and its metabolites (eg, cotinine), and metabolites of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). Cotinine is the preferred blood, saliva and urine biomarker for SHSe. Cotinine and nicotine can also be measured in hair and toenails. NNAL (4-[methylnitrosamino]-1-[3-pyridyl]-1-butanol), a metabolite of NNK, can be determined in the urine of SHS-exposed non-smokers. The selection of a particular biomarker of SHSe and the analytic biological medium depends on the scientific or public health question of interest, study design and setting, subjects, and funding. This manuscript summarises the scientific evidence on the use of biomarkers to measure SHSe, analytical methods, biological matrices and their interpretation.

Methyl Tertiary Butyl Ether in Human Blood after Exposure to Oxygenated Fuel in Fairbanks, Alaska

Residents of Fairbanks, Alaska reported health complaints when 15%, by volume, methyl tertiary butyl ether (MTBE) was added to gasoline during an oxygenated fuel program. We conducted an exposure survey to investigate the effect of the program on human exposure to MTBE. We studied 18 workers in December 1992 during the program and 28 workers in February 1993 after the program was suspended. All workers were heavily exposed to motor vehicle exhaust or gasoline fumes. In December, the median post-shift blood concentration of MTBE in the workers was 1.8 micrograms/l (range, 0.2-37.0 micrograms/l), and in February the median post-shift blood concentration of MTBE in the 28 workers was 0.24 micrograms/l (range, 0.05-1.44 micrograms/l; p = .0001). Blood MTBE levels were measurably higher during the oxygenated fuel program in Fairbanks than after the program was suspended.

Nicotine Reduction Revisited: Science and Future Directions

Regulation of nicotine levels in cigarettes and other tobacco products is now possible with the passage of the Family Smoking Prevention and Tobacco Control Act (FSPTCA) in 2009, giving the US Food and Drug Administration (FDA) authority to regulate tobacco products, and with Articles 9-11 of the WHO Framework Convention on Tobacco Control. Both regulatory approaches allow establishing product standards for tobacco constituents, including nicotine. The FSPTCA does not allow nicotine levels to be decreased to zero, although the FDA has the authority to reduce nicotine yields to very low, presumably non-addicting levels. The proposal to reduce levels of nicotine to a level that is non-addicting was originally suggested in 1994. Reduction of nicotine in tobacco products could potentially have a profound impact on reducing tobacco-related morbidity and mortality. To examine this issue, two meetings were convened in the US with non-tobacco-industry scientists of varied disciplines, tobacco control policymakers and representatives of government agencies. This article provides an overview of the current science in the area of reduced nicotine content cigarettes and key conclusions and recommendations for research and policy that emerged from the deliberations of the meeting members.

Global surveillance of oral tobacco products: total nicotine, unionised nicotine and tobacco-specific N-nitrosamines

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, chimó, 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.

Influence of tap water quality and household water use activities on indoor air and internal dose levels of trihalomethanes

Individual exposure to trihalomethanes (THMs) in tap water can occur through ingestion, inhalation, or dermal exposure. Studies indicate that activities associated with inhaled or dermal exposure routes result in a greater increase in blood THM concentration than does ingestion. We measured blood and exhaled air concentrations of THM as biomarkers of exposure to participants conducting 14 common household water use activities, including ingestion of hot and cold tap water beverages, showering, clothes washing, hand washing, bathing, dish washing, and indirect shower exposure. We conducted our study at a single residence in each of two water utility service areas, one with relatively high and the other low total THM in the residence tap water. To maintain a consistent exposure environment for seven participants, we controlled water use activities, exposure time, air exchange, water flow and temperature, and nonstudy THM sources to the indoor air. We collected reference samples for water supply and air (pre–water use activity), as well as tap water and ambient air samples. We collected blood samples before and after each activity and exhaled breath samples at baseline and postactivity. All hot water use activities yielded a 2-fold increase in blood or breath THM concentrations for at least one individual. The greatest observed increase in blood and exhaled breath THM concentration in any participant was due to showering (direct and indirect), bathing, and hand dishwashing. Average increase in blood THM concentration ranged from 57 to 358 pg/mL due to these activities. More research is needed to determine whether acute and frequent exposures to THM at these concentrations have public health implications. Further research is also needed in designing epidemiologic studies that minimize data collection burden yet maximize accuracy in classification of dermal and inhalation THM exposure during hot water use activities.

Children's exposure to volatile organic compounds as determined by longitudinal measurements in blood

Blood concentrations of 11 volatile organic compounds (VOCs) were measured up to four times over 2 years in a probability sample of more than 150 children from two poor, minority neighborhoods in Minneapolis, Minnesota. Blood levels of benzene, carbon tetrachloride, trichloroethene, and m-/p-xylene were comparable with those measured in selected adults from the Third National Health and Nutrition Examination Survey (NHANES III), whereas concentrations of ethylbenzene, tetrachloroethylene, toluene, 1,1,1-trichloroethane, and o-xylene were two or more times lower in the children. Blood levels of styrene were more than twice as high, and for about 10% of the children 1,4-dichlorobenzene levels were ≥10 times higher compared with NHANES III subjects. We observed strong statistical associations between numerous pairwise combinations of individual VOCs in blood (e.g., benzene and m-/p-xylene, m-/p-xylene and o-xylene, 1,1,1-trichloroethane and m-/p-xylene, and 1,1,1-trichloroethane and trichloroethene). Between-child variability was higher than within-child variability for 1,4-dichlorobenzene and tetrachloroethylene. Between- and within-child variability were approximately the same for ethylbenzene and 1,1,1-trichloroethane, and between-child was lower than within-child variability for the other seven compounds. Two-day, integrated personal air measurements explained almost 79% of the variance in blood levels for 1,4-dichlorobenzene and approximately 20% for tetrachloroethylene, toluene, m-/p-xylene, and o-xylene. Personal air measurements explained much less of the variance (between 0.5 and 8%) for trichloroethene, styrene, benzene, and ethylbenzene. We observed no significant statistical associations between total urinary cotinine (a biomarker for exposure to environmental tobacco smoke) and blood VOC concentrations. For siblings living in the same household, we found strong statistical associations between measured blood VOC concentrations.

Simultaneous analysis of 28 urinary VOC metabolites using ultra high performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (UPLC-ESI/MSMS) ☆

Volatile organic compounds (VOCs) are ubiquitous in the environment, originating from many different natural and anthropogenic sources, including tobacco smoke. Long-term exposure to certain VOCs may increase the risk for cancer, birth defects, and neurocognitive impairment. Therefore, VOC exposure is an area of significant public health concern. Urinary VOC metabolites are useful biomarkers for assessing VOC exposure because of non-invasiveness of sampling and longer physiological half-lives of urinary metabolites compared with VOCs in blood and breath. We developed a method using reversed-phase ultra high performance liquid chromatography (UPLC) coupled with electrospray ionization tandem mass spectrometry (ESI/MSMS) to simultaneously quantify 28 urinary VOC metabolites as biomarkers of exposure. We describe a method that monitors metabolites of acrolein, acrylamide, acrylonitrile, benzene, 1-bromopropane, 1,3-butadiene, carbon-disulfide, crotonaldehyde, cyanide, N,N-dimethylformamide, ethylbenzene, ethylene oxide, propylene oxide, styrene, tetrachloroethylene, toluene, trichloroethylene, vinyl chloride and xylene. The method is accurate (mean accuracy for spiked matrix ranged from 84 to 104%), sensitive (limit of detection ranged from 0.5 to 20 ng mL(-1)) and precise (the relative standard deviations ranged from 2.5 to 11%). We applied this method to urine samples collected from 1203 non-smokers and 347 smokers and demonstrated that smokers have significantly elevated levels of tobacco-related biomarkers compared to non-smokers. We found significant (p<0.0001) correlations between serum cotinine and most of the tobacco-related biomarkers measured. These findings confirm that this method can effectively quantify urinary VOC metabolites in a population exposed to volatile organics.

Levels of Tobacco-Specific Nitrosamines and Polycyclic Aromatic Hydrocarbons in Mainstream Smoke from Different Tobacco Varieties

It has been estimated that one in every five cancer deaths worldwide are related to tobacco use. According to the IARC, 10 polycyclic aromatic hydrocarbons (PAH) and 8 tobacco-specific nitrosamines (TSNA), as well as at least 45 other compounds or substances found in tobacco smoke, are potential human carcinogens. The levels of these carcinogens in contents of tobacco and smoke emissions vary between different tobacco products. We evaluated mainstream smoke emissions from cigarettes made with different types of tobacco to examine the relation between their deliveries of TSNAs and PAHs and any possible influence from tobacco nitrate content. To investigate the contribution of tobacco content to mainstream cigarette smoke deliveries without confounders such as filter design, filter ventilation, and paper porosity, we used custom-made, research-grade, unfiltered cigarettes that contained bright, burley, oriental, reconstituted, or mixtures of these tobaccos. Our findings confirm results from other researchers that tobacco type can influence the mainstream smoke delivery of nicotine, TSNAs, and PAHs. However, we found that the effect varies among individual compounds. In addition, we observed a statistically significant relationship between nitrate content and mainstream smoke 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK); nitrate level also influenced the mainstream smoke deliveries of the summed total of the 10 PAHs identified by IARC as potential human carcinogens. The influence of nitrate on mainstream smoke NNK and PAH levels were of different magnitude and direction. Our results tend to indicate an inverse relation exists between NNK and PAH deliveries when considering different tobacco blends. (Cancer Epidemiol Biomarkers Prev 2008;17(12):3366–71)

Exposure to methyl tertiary-butyl ether from oxygenated gasoline in Stamford, Connecticut.

In 1993, state health officials in Connecticut invited the Centers for Disease Control and Prevention (CDC) to assist in an investigation of exposure to methyl tertiary-butyl ether in oxygenated gasoline in Stamford, Connecticut. Venous blood samples were collected from 14 commuters and from 30 other persons who worked in the vicinity of traffic or automobiles, and the samples were analyzed for methyl tertiary-butyl ether, tertiary-butyl alcohol, benzene, m-/p-xylene, o-xylene, and toluene. The highest levels of methyl tertiary-butyl ether in blood were measured among gasoline service station attendants (median = 15 micrograms/l, range = 7.6-28.9 micrograms/l). Blood levels of methyl tertiary-butyl ether were highly variable among persons who worked in car-repair shops (median = 1.73 micrograms/l, range = 0.17-36.7 micrograms/l) and were generally lowest among commuters (median = 0.11 micrograms/l, range = < 0.05-2.60 micrograms/l). Blood levels of methyl tertiary-butyl ether were correlated strongly with personal-breathing-zone samples of methyl tertiary-butyl ether and blood levels of other volatile organic compounds. This exposure information should prove useful to a future risk analysis of this high-volume chemical.