Medicine and Health Sciences Commons^™

Nicotine In Tobacco Product Aerosols: 'It's Deja Vu All Over Again', Anna K. Duell, James F. Pankow, David H. Peyton

Chemistry Faculty Publications and Presentations

Introduction: The distribution of nicotine among its free-base (fb) and protonated forms in aerosolised nicotine affects inhalability. It has been manipulated in tobacco smoke and now in electronic cigarettes by the use of acids to de-freebase nicotine and form ‘nicotine salts’.

Methods: Measurements on electronic cigarette fluids (e-liquids) were carried out to determine (1) the fraction of nicotine in the free-base form (α fb) and (2) the levels of organic acid(s) and nicotine. Samples included JUUL ‘pods’, ‘look-a-like/knock-off’ pods and some bottled ‘nicotine salt’ and ‘non-salt’ e-liquids.

Results: α fb= 0.12 ±0.01 at 40°C (≈ 37°C) for 10 JUUL products, …

E-Cigarette Chemistry And Analytical Detection, Robert M. Strongin

Chemistry Faculty Publications and Presentations

The study of e-cigarette aerosol properties can inform public health while longer-term epidemiological investigations are ongoing. The determination of aerosol levels of known toxins, as well as of molecules with unknown inhalation toxicity profiles, affords specific information for estimating the risks of e-cigarettes and for uncovering areas that should be prioritized for further investigation.

Benzene Formation In Electronic Cigarettes, James F. Pankow, Kilsun Kim, Kevin J. Mcwhirter, Wentai Luo, Jorge O. Escobedo, Robert M. Strongin, Anna K. Duell, David H. Peyton

Chemistry Faculty Publications and Presentations

The heating of the fluids used in electronic cigarettes (“e-cigarettes”) used to create “vaping” aerosols is capable of causing a wide range of degradation reaction products. We investigated formation of benzene (an important human carcinogen) from e-cigarette fluids containing propylene glycol (PG), glycerol (GL), benzoic acid, the flavor chemical benzaldehyde, and nicotine.

Distribution, Quantification And Toxicity Of Cinnamaldehyde In Electronic Cigarette Refill Fluids And Aerosols, Rachel Z. Behar, Wentai Luo, Sabrina C. Lin, Yuhuan Wang, Jackelyn Valle, James F. Pankow, Prue Talbot

Chemistry Faculty Publications and Presentations

Objective The aim of this study was to evaluate the distribution, concentration and toxicity of cinnamaldehyde in electronic cigarette (e-cigarette) refill fluids and aerosols.

Methods The distribution and concentration of cinnamaldehyde were determined in 39 e-cigarette refill fluids plus 6 duplicates using gas chromatography and mass spectrometry (GC/MS). A cinnamaldehyde toxicity profile was established for embryonic and adult cells using a live cell imaging assay, immunocytochemistry, the comet assay and a recovery assay.

Results Twenty of the 39 refill fluids contained cinnamaldehyde at concentrations that are cytotoxic to human embryonic and lung cells in the MTT assay. Cinnamon Ceylon aerosol …

Formaldehyde From E-Cigarettes - It's Not As Simple As Some Suggest, James F. Pankow, Robert M. Strongin, David H. Peyton

Chemistry Faculty Publications and Presentations

The Authors address critics of a previously published letter to the Editor in The New England Journal of Medicine, pertaining to hidden formaldehyde in E-Cigarette aerosols and the need for future testing of their safety.

Flavour Chemicals In Electronic Cigarette Fluids, Peyton A. Tierney, Clarissa D. Karpinski, Jessica E. Brown, Wentai Luo, James F. Pankow

Chemistry Faculty Publications and Presentations

Background: Most e-cigarette liquids contain flavour chemicals. Flavour chemicals certified as safe for ingestion by the Flavor Extracts Manufacturers Association may not be safe for use in e-cigarettes. This study identified and measured flavour chemicals in 30 e-cigarette fluids.

Methods: Two brands of single-use e-cigarettes were selected and their fluids in multiple flavour types analysed by gas chromatography/mass spectrometry. For the same flavour types, and for selected confectionary flavours (eg, bubble gum and cotton candy), also analysed were convenience samples of e-cigarette fluids in refill bottles from local ‘vape’ shops and online retailers.

Results: In many liquids, total flavour chemicals …

Identification Of Cisplatin-Binding Proteins Using Agarose Conjugates Of Platinum Compounds, Takatoshi Karasawa, Martha Sibrian-Vazquez, Robert M. Strongin, Peter S. Steyger

Chemistry Faculty Publications and Presentations

Cisplatin is widely used as an antineoplastic drug, but its ototoxic and nephrotoxic side-effects, as well as the inherent or acquired resistance of some cancers to cisplatin, remain significant clinical problems. Cisplatin’s selectivity in killing rapidly proliferating cancer cells is largely dependent on covalent binding to DNA via cisplatin’s chloride sites that had been aquated. We hypothesized that cisplatin’s toxicity in slowly proliferating or terminally differentiated cells is primarily due to drug-protein interactions, instead of drug-DNA binding. To identify proteins that bind to cisplatin, we synthesized two different platinum-agarose conjugates, one with two amino groups and another with two chlorides …

Dimethyl Sulfoxide (Dmso) Exacerbates Cisplatin-Induced Sensory Hair Cell Death In Zebrafish (Danio Rerio), Phillip M. Uribe, Melissa A. Mueller, Julia S. Gleichman, Matthew D. Kramer, Qi Wang, Martha Sibrian-Vazquez, Robert M. Strongin, Peter S. Steyger, Douglas A. Cotanche, Jonathan I. Matsui

Chemistry Faculty Publications and Presentations

Inner ear sensory hair cells die following exposure to aminoglycoside antibiotics or chemotherapeutics like cisplatin, leading to permanent auditory and/or balance deficits in humans. Zebrafish (Danio rerio) are used to study drug-induced sensory hair cell death since their hair cells are similar in structure and function to those found in humans. We developed a cisplatin dose-response curve using a transgenic line of zebrafish that expresses membrane-targeted green fluorescent protein under the control of the Brn3c promoter/enhancer. Recently, several small molecule screens have been conducted using zebrafish to identify potential pharmacological agents that could be used to protect sensory hair cells …

Reversed Chloroquine Molecules As A Strategy To Overcome Resistance In Malaria, David H. Peyton

Chemistry Faculty Publications and Presentations

This short review tells the story of how Reversed Chloroquine drugs (RCQs) were developed. These are hybrid molecules, made by combining the quinoline nucleus from chloroquine (CQ) with moieties which are designed to inhibit efflux via known transporters in the membrane of the digestive vacuole of the malaria parasite. The resulting RCQ drugs can have potencies exceeding that of CQ, while at the same time having physical chemical characteristics that may make them favorable as partner drugs in combination therapies. The need for such novel antimalarial drugs will continue for the foreseeable future.

Hiv-1 Matrix Protein Binding To Rna, Ayna Alfadhli, Henry Mcnett, Seyram Tsagli, Hans Peter Bachinger, David H. Peyton

Chemistry Faculty Publications and Presentations

The matrix (MA) domain of the HIV-1 precursor Gag (PrGag) protein plays multiple roles in the viral replication cycle. One essential role is to target PrGag proteins to their lipid raft-associated phosphatidylinositol-(4,5)-bisphosphate (PI[4,5]P2) assembly sites at the plasma membranes (PMs) of infected cells. In addition to this role, several reports have implicated nucleic acid binding properties to retroviral MAs. Evidence indicates that RNA binding enhances the binding specificity of MA to PI(4,5)P2-containing membranes, and supports a hypothesis in which RNA binding to MA acts as a chaperone that protects MA from associating with inappropriate cellular membranes prior to PrGag delivery …

Electrical Detection Of The Temperature Induced Melting Transition Of A Dna Hairpin Covalently Attached To Gold Interdigitated Microelectrodes, Greg P. Brewood, Yaswanth Rangineni, Daniel J. Fish, Ashwini Bhandiwad, David R. Evans, Raj Solanki, Albert S. Benight

Chemistry Faculty Publications and Presentations

The temperature induced melting transition of a self-complementary DNA strand covalently attached at the 5' end to the surface of a gold interdigitated microelectrode (GIME) was monitored in a novel, label-free, manner. The structural state of the hairpin was assessed by measuring four different electronic properties of the GIME (capacitance, impedance, dissipation factor and phase angle) as a function of temperature from 25 degrees C to 80 degrees C. Consistent changes in all four electronic properties of the GIME were observed over this temperature range, and attributed to the transition of the attached single-stranded DNA (ssDNA) from an intramolecular, folded …

Dna Multiplex Hybridization On Microarrays And Thermodynamic Stability In Solution: A Direct Comparison, Daniel J. Fish, M. Todd Horne, Greg P. Brewood, Jim P. Goodarzi, Saba Alemayehu, Ashwini Bhandiwad, Robert P. Searles, Albert S. Benight

Chemistry Faculty Publications and Presentations

Hybridization intensities of 30 distinct short duplex DNAs measured on spotted microarrays, were directly compared with thermodynamic stabilities measured in solution. DNA sequences were designed to promote formation of perfect match, or hybrid duplexes containing tandem mismatches. Thermodynamic parameters DeltaH degrees , DeltaS degrees and DeltaG degrees of melting transitions in solution were evaluated directly using differential scanning calorimetry. Quantitative comparison with results from 63 multiplex microarray hybridization experiments provided a linear relationship for perfect match and most mismatch duplexes. Examination of outliers suggests that both duplex length and relative position of tandem mismatches could be important factors contributing to …