The mouse lymphoma thymidine kinase assay for the assessment and comparison of the mutagenic activity of cigarette mainstream smoke particulate phase

Chemical analysis of up to 49 harmful and potentially harmful constituents (HPHC) in mainstream smoke, in vitro cytotoxicity of the particulate and gas/vapor phase of mainstream smoke determined in the Neutral Red Uptake assay, and in vitro bacterial mutagenicity of the particulate phase determined in the Salmonella typhimurium Reverse Mutation (Ames) assay are reported for three Electrically Heated Cigarette Smoking System (EHCSS) series-K cigarettes, the University of Kentucky Reference Cigarette 2R4F, and a number of comparator commercial conventional lit-end cigarettes (CC) under ISO machine-smoking conditions and a total of 25 additional smoking regimens reflecting 'human puffing behavior' (HPB). The smoking machines were set to deliver nicotine yields for the EHCSS and comparator CC derived from the 10th percentile to the 90th percentile of nicotine uptake distributions in smokers determined in two clinical studies. Duplication of the smoking intensity 'per cigarette' on a smoking machine may provide an insight into product performance that is directly relevant to obtaining scientific evidence for reduced exposure substantiation based on mainstream cigarette smoke HPHC-to-nicotine regressions. The reported data support an overall evaluation of reduced exposure to HPHC and biological activity.

Section: Introductionmentioning

confidence: 99%

Reduced exposure evaluation of an Electrically Heated Cigarette Smoking System. Part 2: Smoke chemistry and in vitro toxicological evaluation using smoking regimens reflecting human puffing behavior

Zenzen

Diekmann

Gerstenberg

et al. 2012

“…Genotoxicity of eugenol and TPM was assessed in the Mouse Lymphoma Assay (MLA) developed by Clive (Clive et al, 1972), and was performed according to OECD guideline 476 (OECD, 1997b) in the microtiter plate version (Cole et al, 1986) as described in detail by Schramke et al (2006). of water was decreased up to À20%.…”

Section: In Vitro Mammalian Cell Genotoxicitymentioning

confidence: 99%

Toxicological assessment of kretek cigarettes part 4: Mechanistic investigations, smoke chemistry and in vitro toxicity

Roemer

Dempsey

Lawless-Pyne

et al. 2014

Self Cite

The smoke chemistry and in vitro toxicity of mainstream smoke (MS) was investigated in American-blended cigarettes with or without the addition of 2.5%, 5% or 10% eugenol to the tobacco and in Indonesian-blended cigarettes with and without the addition of cloves, cloves extracted with hot ethanol, and extracted cloves replenished with eugenol or clove oil. The addition of eugenol reduced the concentration of nearly all toxicants measured in MS as well as the in vitro cytotoxicity of the gas/vapor phase. Reductions were also seen in bacterial mutagenicity of the total particulate matter (TPM) assessed by the Ames Assay. The addition of extracted cloves led to increases and decreases of toxicant concentrations in MS. Replenishment with eugenol or clove oil decreased the toxicant concentrations; with most smoke constituent concentrations reduced below the concentration found in tobacco-only cigarettes. Cytotoxicity of the TPM was not affected by the clove preparations. However, GVP cytotoxicity was reduced (untreated cloves showing the highest reductions). Mutagenicity of TPM was decreased by the clove preparations. Mechanisms for the reductions, (up to 40%), are most likely due to dilution effects by eugenol, changed burning characteristics of the tobacco, and free radical scavenging by eugenol.

“…On a per milligram total particulate matter (TPM) basis the concentration of formaldehyde was increased approximately sevenfold (Stabbert et al, 2003). The in vitro genotoxicity and cytotoxicity of mainstream smoke (Tewes et al, 2003;Roemer et al, 2004;Schramke et al, 2006) and the biological activity of mainstream smoke was reduced in a 90-day sub-chronic rat inhalation study, compared to the 1R4F cigarette (Terpstra et al, 2003). A clinical evaluation performed in the US confirmed that exposure to selected mainstream cigarette smoke constituents was reduced (Roethig et al, 2005).…”

Section: The Electrically Heated Cigarette Smoking System (Ehcss)mentioning

confidence: 96%

Reduced exposure evaluation of an Electrically Heated Cigarette Smoking System. Part 1: Non-clinical and clinical insights

Schorp

Tricker

Dempsey

2012

The following series of papers presents an extensive assessment of the Electrically Heated Cigarette Smoking System EHCSS series-K cigarette vs. conventional lit-end cigarettes (CC) as an example for an extended testing strategy for evaluation of reduced exposure. The EHCSS produces smoke through electrical heating of tobacco. The EHCSS series-K heater was designed for exclusive use with EHCSS cigarettes, and cannot be used to smoke (CC). Compared to the University of Kentucky Reference Research cigarette 2R4F and a series of commercial CC, mainstream cigarette smoke of both the non-menthol and menthol-flavored EHCSS cigarettes showed a reduced delivery of a series of selected harmful and potentially harmful constituents (HPHC), mutagenic activity determined using the Salmonella typhimurium Reverse Mutation (Ames) assay, and cytotoxicity in the Neutral Red Uptake Assay. Clinical evaluations confirmed reduced exposure to HPHC and excretion of mutagenic material under controlled clinical conditions. Reductions in HPHC exposure were confirmed in a real-world ambulatory clinical study. Potential biomarkers of cardiovascular risk were also reduced under real-world ambulatory conditions. A modeling approach, 'nicotine bridging', was developed based on the determination of nicotine exposure in clinical evaluations which indicated that exposure to HPHC for which biomarkers of exposure do not exist would also be reduced.