An in vitro toxicological assessment of two electronic cigarettes: E-liquid to aerosolisation

Interest in the toxicological assessment of iterations of e-cigarette devices, e-liquid formulations and flavour use is increasing. Here, we describe a multiple test matrix and in vitro approach to assess the biological impact of differing e-cigarette activation mechanism (button vs. puff-activated) and heating technology (cotton vs. ceramic wick). The e-liquids selected for each device contained the same nicotine concentration and flavourings. We tested both e-liquid and aqueous extract of e-liquid aerosol using a high throughput cytotoxicity and genotoxicity screen. We also conducted whole aerosol assessment both in a reconstituted human airway lung tissue (MucilAir) with associated endpoint assessment (cytotoxicity, TEER, cilia beat frequency and active area) and an Ames whole aerosol assay with up to 900 consecutive undiluted puffs. Following this testing it is shown that the biological impact of these devices is similar, taking into consideration the limitations and capturing efficiencies of the different testing matrices. We have contextualised these responses against previous published reference cigarette data to establish the comparative reduction in response consistent with reduced risk potential of the e-cigarette products tested in this study as compared to conventional cigarettes.

A contextualised e-cigarette testing strategy shows flavourings do not impact lung toxicity in vitro

Vaping has the potential to reduce the individual health risks associated with smoking and e-cigarette flavours have been reported to help smokers' transition from cigarettes. In this manuscript, we provide evidence to support the reduced risk potential of e-cigarette aerosols and flavours by assessing commercially available e-liquids (Vuse ePod - Manufactured by British American Tobacco) in a 2D in vitro screening approach. We also analysed selected flavours using a more physiologically relevant 3D (MucilAir) whole aerosol exposure model, measuring toxicity and functional endpoints such as Trans Epithelial Electrical Resistance, Cilia Beat Frequency and Active Area. To contextualise responses, we have compared e-cigarette aerosol to cigarette smoke (1R6F research cigarette) and calculated the percentage reduction using a point of departure approach. We show that aerosolised flavoured e-liquids, (appropriately stewarded) do not increase the overall measured aerosol toxicity when compared to cigarette smoke. In fact, we demonstrate that the measured in vitro cellular toxicity of flavoured e-cigarette products remains >95% reduced when compared to cigarette smoke toxicity, using point of departure (IC₈₀) approach. These data indicate that the overall product toxicity is not increased in a flavour dependent manner and that flavoured e-cigarette products can potentially play a role in tobacco harm reduction.

A 3D in vitro comparison of two undiluted e-cigarette aerosol generating systems

In vitro studies play an important role in supporting the toxicological assessment of e-cigarettes, with many current methods reliant on sophisticated in vitro exposure systems designed for conventional cigarette testing. In this study, we have compared two distinct systems; the modified Vitrocell VC10 and Borgwaldt LM4E designed to deliver undiluted e-cigarette aerosol. We assessed the cytotoxicity response of 3D reconstituted lung tissue (MucilAir) exposed to undiluted aerosol from ePen3 (closed modular e-cigarette) using these two exposure systems. As the induced cytotoxicity profiles were comparable, we then compared these responses against historical eBox (open modular e-cigarette) and 3R4F reference cigarette data to show evolution of product technology. This latter approach was deemed possible by monitoring intrinsic donor-to-donor control variability over a three-year period, bridging between exposure systems and observed biological responses. Despite the differences in the technology, on a puff-by-puff basis these machines gave remarkably similar cytotoxicity profiles for ePen3, as determined by MTT, and consistency of pre-cytotoxicity markers: transepithelial electrical resistance (TEER), cilia beat frequency and cilia active area. When responses are compared as a function of exposed nicotine concentration, we see differences due to the dynamics of the exposure systems. The parity of responses between the systems in generated undiluted aerosol has allowed us to compare back to previously published eBox data, irrespective of aerosol generating system and MucilAir donor, showing how evolution from open systems to podmod e-cigarette design can make a step change in the cytotoxicity profile of the product.

A screening approach for the evaluation of tobacco-free 'modern oral' nicotine products using Real Time Cell Analysis

In many regulated industries there is an increasing pressure to provide timely and robust risk assessment data to support product launches. Real-time cell analysis (RTCA) is a tool that allows for the fast and relatively labour-free cytotoxic assessment of test compounds, compared to traditional methods. Here, we propose an application for the RTCA platform to provide a screening approach, to evaluate the cytotoxic potential of tobacco-free nicotine pouches, also termed modern oral product (MOP), to determine the contribution of differing nicotine strengths (4-11 mg) and a range of available flavour types from multiple markets, on overall product toxicity. Aqueous extracts were prepared for all products using 1 pouch in 20 mL cell culture media and applied to the cell system for 24 h. Test extract nicotine concentrations reflected the increases in product nicotine strength; however, these changes were not present in the same magnitude in the cytotoxicity data obtained from both primary human gingival fibroblasts (HGF) and an NCI-H292 human bronchial epithelial continuous cell line. Furthermore, across the range of flavours and product nicotine strengths tested, H292 cells whilst not the target organ for oral product use, accurately predicted the results seen in HGFs and could be considered a useful surrogate for fast screening studies. H292 cells are more easily cultured and for longer periods, offering a more compatible test system. In conclusion, the data demonstrate the utility of the RTCA platform for the quick assessment of a large range of product variants. Furthermore, for a cytotoxicity measure with this test product, the simple H292 cell line can predict outcomes in the more complex HGF and provide useful pre-clinical cytotoxicity screening data to inform the risk assessment of MOPs and the relative contribution of flavourings, nicotine and other components.

The in vitro assessment of a novel vaping technology

We have developed a novel vaping product (NVP) IS1.0(TT), which utilises a stainless-steel mesh to transfer and vaporise the e-liquid, mitigating some of the potential sources of toxicants that can be generated using the more traditional 'wick and coil' approach. The emissions from IS1.0(TT) have previously been found to have lower levels of toxicants overall when directly compared with a commercial wick and coil e-cig. This current study assessed the toxicological responses to aerosols from this NVP. Responses induced by IS1.0(TT)were compared to those from a 3R4F reference cigarette, using in vitro test methods which included regulatory genetic toxicological assays as well as some more contemporary screening approaches. The experimental conditions were designed to facilitate the testing of aerosol from this vaping product at doses that in most cases greatly exceeded those of the 3R4F comparator showed little to no toxicological responses and demonstrated significantly reduced effects in these in vitro assays when compared to 3R4F. Furthermore, the extreme doses tested in the present study indicate that the toxicant profile of this NVP translates to lower biological activity in vitro, and suggests that the absolute risk hazard level associated with electronic cigarettes can be reduced through continuous improvement as the technology evolves.

The mutagenic assessment of an electronic-cigarette and reference cigarette smoke using the Ames assay in strains TA98 and TA100

Salmonella typhimurium strains TA98 and TA100 were used to assess the mutagenic potential of the aerosol from a commercially available, rechargeable, closed system electronic-cigarette. Results obtained were compared to those for the mainstream smoke from a Kentucky reference (3R4F) cigarette. Two different test matrices were assessed. Aerosol generated from the e-cigarette was trapped on a Cambridge filter pad, eluted in DMSO and compared to cigarette smoke total particulate matter (TPM), which was generated in the same manner for mutagenicity assessment in the Salmonella assay. Fresh e-cigarette and cigarette smoke aerosols were generated on the Vitrocell® VC 10 smoking robot and compared using a modified scaled-down 35mm air agar interface (AAI) methodology. E-cigarette aerosol collected matter (ACM) was found to be non-mutagenic in the 85mm plate incorporation Ames assay in strains TA98 and TA100 conducted in accordance with OECD 471, when tested up to 2400μg/plate. Freshly generated e-cigarette aerosol was also found to be negative in both strains after an AAI aerosol exposure, when tested up to a 1L/min dilution for up to 3h. Positive control responses were observed in both strains, using benzo[a]pyrene, 2-nitrofluorene, sodium azide and 2-aminoanthracene in TA98 and TA100 in the presence and absence of metabolic activation respectively. In contrast, cigarette smoke TPM and aerosol from 3R4F reference cigarettes were found to be mutagenic in both tester strains, under comparable test conditions to that of e-cigarette exposure. Limited information exists on the mutagenic activity of captured e-cigarette particulates and whole aerosol AAI approaches. With the lower toxicant burden of e-cigarette aerosols compared to cigarette smoke, it is clear that a more comprehensive Ames package of data should be generated when assessing e-cigarettes, consisting of the standard OECD-five, TA98, TA100, TA1535, TA1537 (or TA97) and E. coli (or TA102). In addition, TA104 which is more sensitive to the carbonyl based compounds found in e-cigarette aerosols under dry-wicking conditions may also prove a useful addition in a testing battery. Regulatory standard product testing approaches as used in this study will become important when determining whether e-cigarette aerosols are in fact less biologically active than cigarette smoke, as this study suggests. Future studies should be supported by in vitro dosimetry approaches to draw more accurate comparisons between cigarette smoke, e-cigarette aerosol exposure and human use.

An inter-machine comparison of tobacco smoke particle deposition in vitro from six independent smoke exposure systems

There are several whole smoke exposure systems used to assess the biological and toxicological impact of tobacco smoke in vitro. One such system is the Vitrocell® VC 10 Smoking Robot and exposure module. Using quartz crystal microbalances (QCMs) installed into the module, we were able to assess tobacco smoke particle deposition in real-time. We compared regional deposition across the module positions and doses delivered by six VC 10s in four independent laboratories: two in the UK, one in Germany and one in China. Gauge R&r analysis was applied to the total data package from the six VC 10s. As a percentage of the total, reproducibility (between all six VC 10s) and repeatability (error within an individual VC 10) accounted for 0.3% and 7.4% respectively. Thus Gauge R&r was 7.7%, less than 10% overall and considered statistically fit for purpose. The dose-responses obtained from the six machines across the four different locations demonstrated excellent agreement. There were little to no positional differences across the module at all airflows as determined by ANOVA (except for one machine and at three airflows only). These results support the on-going characterisation of the VC 10 exposure system and suitability for tobacco smoke exposure in vitro.

Utopia documents: linking scholarly literature with research data

Motivation: In recent years, the gulf between the mass of accumulating-research data and the massive literature describing and analyzing those data has widened. The need for intelligent tools to bridge this gap, to rescue the knowledge being systematically isolated in literature and data silos, is now widely acknowledged.

Results: To this end, we have developed Utopia Documents, a novel PDF reader that semantically integrates visualization and data-analysis tools with published research articles. In a successful pilot with editors of the Biochemical Journal (BJ), the system has been used to transform static document features into objects that can be linked, annotated, visualized and analyzed interactively (http://www.biochemj.org/bj/424/3/). Utopia Documents is now used routinely by BJ editors to mark up article content prior to publication. Recent additions include integration of various text-mining and biodatabase plugins, demonstrating the system's ability to seamlessly integrate on-line content with PDF articles.

Availability:http://getutopia.com

Contact:teresa.k.attwood@manchester.ac.uk

WIWS: a protein structure bioinformatics Web service collection

The WHAT IF molecular-modelling and drug design program is widely distributed in the world of protein structure bioinformatics. Although originally designed as an interactive application, its highly modular design and inbuilt control language have recently enabled its deployment as a collection of programmatically accessible web services. We report here a collection of WHAT IF-based protein structure bioinformatics web services: these relate to structure quality, the use of symmetry in crystal structures, structure correction and optimization, adding hydrogens and optimizing hydrogen bonds and a series of geometric calculations. The freely accessible web services are based on the industry standard WS-I profile and the EMBRACE technical guidelines, and are available via both REST and SOAP paradigms. The web services run on a dedicated computational cluster; their function and availability is monitored daily.

An active registry for bioinformatics web services

Summary: The EMBRACE Registry is a web portal that collects and monitors web services according to test scripts provided by the their administrators. Users are able to search for, rank and annotate services, enabling them to select the most appropriate working service for inclusion in their bioinformatics analysis tasks.

Availability and implementation: Web site implemented with PHP, Python, MySQL and Apache, with all major browsers supported. (www.embraceregistry.net)

Contact:steve.pettifer@manchester.ac.uk

Intermediate care. Homeward bound

Establishing a community acute and rehabilitation team for stroke patients has reduced the length of acute inpatient stay from 23 to eight days, without adversely affecting outcomes. The numbers of GPs referring directly to the community stroke team exceeded expectations (37 per cent of all referrals), avoiding accident and emergency admissions. Establishing good inter-agency agreements was crucial to the success of the project.

Neural basis of alertness and cognitive performance impairments during sleepiness. I. Effects of 24 h of sleep deprivation on waking human regional brain activity

The negative effects of sleep deprivation on alertness and cognitive performance suggest decreases in brain activity and function, primarily in the thalamus, a subcortical structure involved in alertness and attention, and in the prefrontal cortex, a region subserving alertness, attention, and higher-order cognitive processes. To test this hypothesis, 17 normal subjects were scanned for quantifiable brain activity changes during 85 h of sleep deprivation using positron emission tomography (PET) and (18)Fluorine-2-deoxyglucose ((18)FDG), a marker for regional cerebral metabolic rate for glucose (CMRglu) and neuronal synaptic activity. Subjects were scanned prior to and at 24-h intervals during the sleep deprivation period, for a total of four scans per subject. During each 30 min (18)FDG uptake, subjects performed a sleep deprivation-sensitive Serial Addition/Subtraction task. Polysomnographic monitoring confirmed that subjects were awake. Twenty-four hours of sleep deprivation, reported here, resulted in a significant decrease in global CMRglu, and significant decreases in absolute regional CMRglu in several cortical and subcortical structures. No areas of the brain evidenced a significant increase in absolute regional CMRglu. Significant decreases in relative regional CMRglu, reflecting regional brain reductions greater than the global decrease, occurred predominantly in the thalamus and prefrontal and posterior parietal cortices. Alertness and cognitive performance declined in association with these brain deactivations. This study provides evidence that short-term sleep deprivation produces global decreases in brain activity, with larger reductions in activity in the distributed cortico-thalamic network mediating attention and higher-order cognitive processes, and is complementary to studies demonstrating deactivation of these cortical regions during NREM and REM sleep.

A comparison of subcutaneous morphine and fentanyl in hospice cancer patients

This study compares subcutaneous (s.c.) morphine and fentanyl with respect to pain control and side effects using a 6-day randomized, double-blind, cross-over design. Results were obtained from 23 patients (12 males and 11 females: mean age of 70.5 years) who could tolerate morphine. Thirteen patients were randomized to receive morphine for the first 3 days followed by fentanyl; 10 received fentanyl first followed by morphine. There were no significant differences in the scores for pain between the two drugs, suggesting that fentanyl is equally efficacious and the conversion ratio of morphine 10 mg: fentanyl 150 micrograms is appropriate. Patients had more frequent bowel movements during days 4-6 while on the fentanyl arm [t-test, df (22), P = 0.015]. Other measures for nausea, delirium, and cognitive function showed no differences between the two drugs. This study highlights the need to further assess the role of various opioids in hospice patients, and emphasizes the requirement for sensitive and simple cognitive tests in this population.

Dextromoramide pharmacokinetics following sublingual administration

The extent of absorption and other pharmacokinetic parameters of dextromoramide following sublingual administration were assessed in five patients receiving chronic opioid analgesia. The use of the standard 5 mg tablet formulation was associated with negligible absorption in two patients, a prolonged time to peak concentration in the other three and substantial variability in clearance. The study concluded that the standard tablet formulation cannot be recommended for sublingual use where reliable, rapid onset analgesia is required.

Reusing disposables: same old story--more characters added

In recent years health care professionals have become increasingly concerned with the economic issues of patient care. One of the most controversial issues is the practice of reprocessing items labeled "single use." Professionals in varied health care settings have different priorities to consider on the basis of their clinical responsibilities. This article explores resterilization and reuse considerations, including the use of manufacturers' written guidelines; legal and ethical issues of patient rights; health care providers' responsibilities with regard to informed consents, clinical trials, and testing of reprocessed items; and performing cost comparisons of reused versus single-use items, in both hospital and free-standing health care facilities.

The effects of L-dihydroxyphenylalanine on alertness and mood in alpha-methyl-para-tyrosine-treated healthy humans. Further evidence for the role of catecholamines in arousal and anxiety

Treatment with alpha-methyl-para-tyrosine (AMPT), a catecholamine synthesis inhibitor, has been shown to produce pronounced increases in sleepiness and mild increases in negative mood and anxiety when administered to healthy male adults. The present study was conducted to ascertain whether these effects of AMPT are secondary to decreases in brain catecholamines or whether they represent nonspecific drug effects. Forty-one healthy males were randomized to one of four treatment groups. (1) Treatment with AMPT alone (AMPT/placebo); (2) treatment with AMPT plus L-dopa/carbidopa (AMPT plus L-dopa/carbidopa); (3) treatment with L-dopa/carbidopa alone (placebo plus L-dopa/carbidopa); or (4) treatment with placebo alone (placebo plus placebo). Repeated measures of alertness, mood, and anxiety were obtained over a three-day period of drug treatment and following drug discontinuation. As before, AMPT treatment led to increased sleepines. In addition, AMPT treatment led to decreased calmness, increased tension and anger, and a trend for increased depression. Replacement of catecholamine stores with L-dopa reversed the effects of AMPT and was associated with a more rapid recovery from AMPT's effects. These findings indicate that AMPT's effects on alertness and anxiety are catecholamine-specific. Further, they provide additional evidence that catecholamines are involved in the regulation of normal states of arousal, and they are consistent with the view that brain catecholaminergic dysregulation is involved in pathological anxiety states.

Effective dose to patients due to fluoroscopic screening in barium meal examinations: comparison between free and restricted X-ray beams

Four complete barium meal (BM) fluoroscopic examinations were digitised as sequences of 160 x 128 pixel, 8 bit images, at a rate of about 100 per min using a computer frame-grabber system and were recorded on disk for processing. The images were latter replayed and, using a suitable program, were superimposed in a new picture so that anatomic details coincided. At the same time, two more pictures were created by summing the radiation fields corresponding to the images grabbed, one with open diaphragms at 26 x 22 cm field size and one with simulated closed diaphragms at 7 x 11 cm. The average effective dose rate delivered to the patient during fluoroscopic screening was calculated for a hermaphrodite mathematical phantom and was found to be 0.21 mSv/min and 0.005 mSv/min, respectively, if either technique had been used exclusively. The average effective dose delivered to the patients with the actual techniques used in the 4 BM examinations recorded was 0.394 mSv. Data from these examinations was extrapolated to a sample group of 122 BM examinations, performed during a 9-week period, for which total exposure duration was known. The average effective dose calculated for fluoroscopy was shown to be negligible, particularly if only the 'closed' diaphragm technique was used, when compared to the estimated average effective dose of about 8.6 mSv delivered by the radiographs made during each examination.

Caffeine reversal of sleep deprivation effects on alertness and mood

This study assessed the ability of high doses of caffeine to reverse changes in alertness and mood produced by prolonged sleep deprivation. Fifty healthy, nonsmoking males between the ages of 18 and 32 served as volunteers. Following 49 h without sleep, caffeine (0, 150, 300, or 600 mg/70 kg, PO) was administered in a double-blind fashion. Measures of alertness were obtained with sleep onset tests, the Stanford Sleepiness Scale (SSS), and Visual Analog Scales (VAS). Sleep deprivation decreased onset to sleep from a rested average of 19.9 min to 7 min. Following the highest dose of caffeine tested, sleep onset averaged just over 10 min; sleep onset for the placebo group averaged 5 min. Scores on the SSS increased from a rested mean of 1.6-4.8 after sleep deprivation. Caffeine reduced this score to near rested values. Caffeine reversed sleep deprivation-induced changes in three subscales of the POMS (vigor, fatigue, and confusion) and produced values close to fully rested conditions on several VAS. Serum caffeine concentrations peaked 90 min after ingestion and remained elevated for 12 h. This study showed that caffeine was able to produce significant alerting and long-lasting beneficial mood effects in individuals deprived of sleep for 48 h.

The effects of d-amphetamine on arousal, cognition, and mood after prolonged total sleep deprivation

Thirty-six normal male subjects underwent total sleep deprivation for 48 hours, were then administered either placebo, 5, 10, or 20 mg of d-amphetamine, and sleep deprived for an additional 12 hours. Sleep deprivation produced a significant reduction in sleep latency, as well as marked decrements in cognitive performance and self-ratings reflecting vigor and fatigue. Amphetamine reversed these effects in a dose-related way but the pattern and persistence of the reversal varied across measures. After 20 mg, sleep latency normalized for several hours, but then declined. Behavioral effects tended to follow the pattern of sleep latency. On cognitive tasks, 20 mg produced a sustained return to normal performance in an attentional arithmetic task and a gradual improvement in a verbal reasoning task. The partial temporal dissociation among sleep latency, behavioral, and cognitive effects suggests that varying doses of amphetamine may have time-related differential neurochemical effects or that various dimensions of arousal and alertness may be differentially sensitive to amphetamine.