Inhalation toxicology
-
Inhalation toxicology · Jul 2009
Evaluation of a novel inhalation exposure system to determine acute respiratory responses to tobacco and polymer pyrolysate mixtures in Swiss-Webster mice.
Modern cigarette production processes are highly automated and yield millions of cigarettes per day. The forming cigarette and its components contact many different materials in the production process, some of which may leave minute residues. The potential for small inclusions of non-cigarette materials such as wood, plastic, cardboard and other materials exists from the bulk handling and processing of tobacco, in spite of vigilant workers and numerous online systems designed to keep the tobacco stream clean. ⋯ These included DIN-generated wet total particulate matter (TPM) DIN-Generated wet TPM (DWTPM), nicotine, cyanide, formaldehyde, acetaldehyde, acrolein, carbon monoxide, carbon dioxide, and nitrogen oxides. We attempted to correlate analyte differences in the test atmospheres with the resulting biological findings in the mice. The results demonstrated that this approach could detect minimal toxicological effects in mice exposed to test atmospheres of 100% tobacco or 70%/30% tobacco/polymer pyrolysates.
-
Inhalation toxicology · Jul 2009
Effect of filtration by activated charcoal on the toxicological activity of cigarette mainstream smoke from experimental cigarettes.
Activated charcoal (AC) filtration reportedly decreases the yields of smoke vapor phase constituents including some identified as human carcinogens and respiratory irritants. Non-clinical studies including chemical smoke analysis, in vitro cytotoxicity and mutagenicity (bacterial and mammalian cells), and in vivo subchronic rat inhalation studies were carried out using machine smoking at ISO conditions with lit-end research cigarettes containing AC filters. The objective was to assess whether AC filter technology would alter the established toxicity profile of mainstream smoke by increasing or decreasing any known toxicological properties, or elicit new ones. ⋯ The in vitro bacterial mutagenicity of AC filtered smoke particulate preparations was occasionally increased over control levels. Laryngeal epithelial thickness was increased in some rats inhaling AC filtered smoke in comparison to controls, an effect perhaps related to higher inspiratory flow. When tested under more intense Massachusetts Department of Public Health smoking conditions, AC filter associated reductions in vapor phase constituent yields were smaller than those seen with ISO conditions, but the effect on in vitro cytotoxicity remained.
-
Inhalation toxicology · Jun 2009
Comparative StudyExposure to cigarette smoke upregulates AP-1 activity and induces TNF-alpha overexpression in mouse lungs.
Cigarette smoke-triggered inflammation is important in the pathophysiology of chronic obstructive pulmonary disease, and involves overexpression of many proinflammatory genes. Transcription factors regulating expression of inflammatory mediators may play a key role in characterizing the disease. To observe alterations in pulmonary function, observe pathological changes in lung tissues, and detect changes in transcriptional factors, mice were exposed to 30 days of cigarette smoke. ⋯ EMSA demonstrated that smoke exposure enhanced activator protein (AP)-1 DNA binding activation, but only slightly changed NF-kappaB activation in mouse lung. Compared to the control group, smoke exposure induced a notable increase in TNF-alpha in BALF. These data demonstrated that subacute smoke-triggered lung inflammation was accompanied by inflammatory cell influx, AP-1 activation, and proinflammatory gene overexpression in mouse lungs.
-
Inhalation toxicology · May 2009
Comparative StudyPrenatal developmental toxicity studies of inhaled methyl iodide vapor in rabbits reveal a susceptible window of exposure inducing late gestational fetotoxicity.
Methyl iodide (MeI), an intermediate used in the manufacture of some insecticides and pharmaceuticals, is under review for U. S. registration as a non-ozone-depleting alternative to methyl bromide in the pre-plant soil fumigation market. Guideline (OPPTS 870.3700) developmental toxicity studies in New Zealand White (NZW) rabbits showed dose-dependent increases in the litter proportions of late fetal deaths and postimplantation loss and/or decreased fetal body weight following inhalation exposure of pregnant rabbits to MeI during gestation days (GD) 6-28. ⋯ No maternal or developmental toxicity was elicited from maternal exposure during GD 6-14, 15-22, or 27-28. However, MeI-related fetotoxicity, including increased litter proportions of late fetal deaths with or without corresponding decreases in fetal body weight, were observed for females exposed during GD 6-28 (p < .01), 23-24 and 25-26. Although the increase in late-stage fetal death for each of the 2-day exposures on GD 23-24 and GD 25-26 was not statistically significant, as noted for the combined total of fetal deaths during the GD 6-28 exposure, it can be deduced that the gestational window of GD 23-26 was the most susceptible window of exposure for eliciting developmental toxicity in rabbits exposed to MeI vapors.
-
Inhalation toxicology · Apr 2009
Comparative StudyDoes use of flue-cured rather than blended cigarettes affect international variation in mortality from lung cancer and COPD?
We compared risk of lung cancer and chronic obstructive pulmonary disease (COPD) associated with flue-cured and blended cigarettes. Mortality and smoking data were collected for 1971-2000 by sex, age, and period for three countries with a mainly flue-cured market and four with a blended market. Epidemiological relative risk estimates for current and ex smoking were summarized. ⋯ There was little indication of any difference between flue-cured and blended cigarettes on risk of lung cancer or COPD. Our approach could have detected differences of about 40% for male lung cancer, or twofold differences for females or for COPD, had they existed. Between-country differences in rates of two major diseases predominantly caused by smoking cannot materially be explained by whether the countries use flue-cured or blended cigarettes.