[Particle size in the smoke produced by six different types of cigarette]

Aerosol droplet-size distribution and airborne nicotine portioning in particle and gas phases emitted by electronic cigarettes

The reliable characterization of particle size distribution and nicotine delivery emitted by electronic cigarettes (ECs) is a critical issue in their design. Indeed, a better understanding of how nicotine is delivered as an aerosol with an appropriate aerodynamic size is a necessary step toward obtaining a well-designed nicotine transfer from the respiratory tract to the bloodstream to better satisfy craving and improve smoking cessation rates. To study these two factors, recent models of EC devices and a dedicated vaping machine were used to generate aerosols under various experimental conditions, including varying the EC power level using two different types of atomizers. The aerodynamic particle sizing of the resulting aerosol was performed using a cascade impactor. The nicotine concentration in the refill liquid and the aerosol droplet was quantified by liquid chromatography coupled with a photodiode array. The vaporization process and the physical and chemical properties of the EC aerosol were very similar at 15 watts (W) and 25 W using the low-power atomizer but quite distinct at 50 W using the high-power atomizer, as follows: (1) the mass median aerodynamic diameters ranged from 1.06 to 1.19 µm (µm) for low power and from 2.33 to 2.46 µm for high power; (2) the nicotine concentrations of aerosol droplets were approximately 11 mg per milliliter (mg/mL) for low power and 17 mg/mL for high power; and (3) the aerosol droplet particle phase of the total nicotine mass emitted by EC was 60% for low power and 95% for high power. The results indicate that varying the correlated factors (1) the power level and (2) the design of atomizer (including the type of coil and the value of resistance used) affects the particle-size distribution and the airborne nicotine portioning between the particle phase and the gas phase in equilibrium with the airborne droplets.

Mechanisms of Particles in Sensitization, Effector Function and Therapy of Allergic Disease

Humans have always been in contact with natural airborne particles from many sources including biologic particulate matter (PM) which can exhibit allergenic properties. With industrialization, anthropogenic and combustion-derived particles have become a major fraction. Currently, an ever-growing number of diverse and innovative materials containing engineered nanoparticles (NPs) are being developed with great expectations in technology and medicine. Nanomaterials have entered everyday products including cosmetics, textiles, electronics, sports equipment, as well as food, and food packaging. As part of natural evolution humans have adapted to the exposure to particulate matter, aiming to protect the individual's integrity and health. At the respiratory barrier, complications can arise, when allergic sensitization and pulmonary diseases occur in response to particle exposure. Particulate matter in the form of plant pollen, dust mites feces, animal dander, but also aerosols arising from industrial processes in occupational settings including diverse mixtures thereof can exert such effects. This review article gives an overview of the allergic immune response and addresses specifically the mechanisms of particulates in the context of allergic sensitization, effector function and therapy. In regard of the first theme (i), an overview on exposure to particulates and the functionalities of the relevant immune cells involved in allergic sensitization as well as their interactions in innate and adaptive responses are described. As relevant for human disease, we aim to outline (ii) the potential effector mechanisms that lead to the aggravation of an ongoing immune deviation (such as asthma, chronic obstructive pulmonary disease, etc.) by inhaled particulates, including NPs. Even though adverse effects can be exerted by (nano)particles, leading to allergic sensitization, and the exacerbation of allergic symptoms, promising potential has been shown for their use in (iii) therapeutic approaches of allergic disease, for example as adjuvants. Hence, allergen-specific immunotherapy (AIT) is introduced and the role of adjuvants such as alum as well as the current understanding of their mechanisms of action is reviewed. Finally, future prospects of nanomedicines in allergy treatment are described, which involve modern platform technologies combining immunomodulatory effects at several (immuno-)functional levels.

Extrafine compared to non-extrafine particle inhaled corticosteroids in smokers and ex-smokers with asthma

BACKGROUND

Smoking is as prevalent in asthmatics as in the general population. Asthmatic smokers benefit less from inhaled corticosteroids (ICS) than non-smoking asthmatics, possibly due to more smoking-induced small airways disease. Thus targeting small airways may be important in treating asthmatic (ex-)smokers. We hypothesized that extrafine particle ICS improve small airways function more than non-extrafine particle ICS in asthmatic (ex-)smokers.

METHODS

We performed an open-label, randomized, three-way cross-over study comparing extrafine beclomethasone (HFA-QVAR) to non-extrafine beclomethasone (HFA-Clenil) and fluticasone (HFA-Flixotide) in 22 smokers and 21 ex-smokers with asthma (?5 packyears).

RESULTS

Improvement from baseline in PD₂₀ adenosine after using QVAR, Clenil or Flixotide was 1.04 ± 1.71, 1.09 ± 2.12 and 0.94 ± 1.97 doubling doses, mean ± standard deviation (SD), respectively. The change from baseline in R₅-R₂₀ at PD₂₀ adenosine after using QVAR, Clenil or Flixotide was ?0.02 ± 0.27, 0.02 ± 0.21, and ?0.02 ± 0.31 kPa sL^?1, mean ± SD, respectively. The change in PD₂₀ adenosine and R₅-R₂₀ at PD₂₀ adenosine were neither statistically significant different between QVAR and Clenil (p = 0.86 and p = 0.82) nor between QVAR and Flixotide (p = 0.50 and p = 0.96).

CONCLUSION

Similar effectiveness in improving small airways function was found for extrafine and non-extrafine particle ICS treatment for asthmatic smokers and ex-smokers.

Characterization of particle size distribution of mainstream cigarette smoke generated by smoking machine with an electrical low pressure impactor

Cigarette smoking is a particle-related exposure. Studying the characteristics of the particle size distribution of cigarette smoke can aid in providing knowledge of smoke aerosol attributes. We used an electrical low pressure impactor (ELPI) to measure the particle size distribution of mainstream cigarette smoke generated by a smoking machine and provided a continuum of particle sizes of cigarette smoke from a whole cigarette. The results showed that the aerodynamic diameters (D, geometric mean of a channel) of particles ranged from 0.021 to 1.956 μm, and the number concentrations were on the order of 10(5)-10(9) cm(-3) for different sizes of particles. The particle number of the size category below 0.1 μm approximated that of the category 0.1-2.0 μm, and the particles in the size category of 0.1-2.0 μm contributed extremely heavily to total particulate mass. In addition, the results with small samples indicated that the tar yields normalized per milligram of nicotine showed an approximately linear increase with increasing concentration of total particles.

Increased frequency of circulating invariant natural killer T cells in malignant pleural mesothelioma patients

Invariant natural killer T (iNKT) cells are a distinct subset of human T cells, which expresses an invariant T cell receptor Vα24 Jα18 and recognizes glycolipid antigens in the context of CD1d molecules. iNKT cells exert pivotal regulatory roles in many immune responses, including antitumor immune responses. Alterations in iNKT cell frequency, phenotype, and activation state have been reported in cancer patients. No data are available on the iNKT cells in malignant pleural mesothelioma (MPM), a rare, but very aggressive, malignancy of the pleura with a very poor prognosis. Here, we studied the frequency, phenotype, and cytokine profile of circulating iNKT cells in MPM patients, and correlated results with tumor histological types (epithelioid, sarcomatoid, biphasic) and clinical stages (I-III). We found that the iNKT cell frequency was significantly increased in MPM patients with epithelioid and sarcomatoid types in comparison with healthy volunteers (HV); only three biphasic mesotheliomas were available in this study, thus no conclusions can be drawn for this MPM type. The increased frequency significantly correlates with the clinical stage of tumor with the highest value at the stage III in both epithelioid and sarcomatoid subtypes. According to the histological types, we measured changes in the frequencies of CD4⁺ CD8⁺ (DP) and CD4⁻CD8⁻ (DN), but not in the cytokine profiles (IFN-γ/IL-4 expression). These results demonstrate that the frequency of iNKT cells is increased in MPM patients and that this increase correlates with MPM type and stage.

Particulate matter in cigarette smoke increases ciliary axoneme beating through mechanical stimulation

BACKGROUND

The lung's ability to trap and clear foreign particles via the mucociliary elevator is an important mechanism for protecting the lung against respirable irritants and microorganisms. Although cigarette smoke (CS) exposure and particulate inhalation are known to alter mucociliary clearance, little is known about how CS and nanoparticles (NPs) modify cilia beating at the cytoskeletal infrastructure, or axonemal, level.

METHODS

We used a cell-free model to introduce cigarette smoke extract (CSE) and NPs with variant size and surface chemistry to isolated axonemes and measured changes in ciliary motility. We hypothesized that CSE would alter cilia beating and that alterations in ciliary beat frequency (CBF) due to particulate matter would be size- and surface chemistry-dependent. Demembranated axonemes were isolated from ciliated bovine tracheas and exposed to adenosine triphosphate (ATP) to initiate motility. CBF was measured in response to 5% CSE, CSE filtrate, and carboxyl-modified (COOH), sulphate (SO(4))-modified (sulfonated), or PEG-coated polystyrene (PS) latex NPs ranging in size from 40 nm to 500 nm.

RESULTS

CSE concentrations as low as 5% resulted in rapid, significant stimulation of CBF (p<0.05 vs. baseline control). Filtering CSE through a 0.2-μm filter attenuated this effect. Introduction of sulphate-modified PS beads ~300 nm in diameter resulted in a similar increase in CBF above baseline ATP levels. Uncharged, PEG-coated beads had no effect on CBF regardless of size. Similarly, COOH-coated particles less than 200 nm in diameter did not alter ciliary motility. However, COOH-coated PS particles larger than 300 nm increased CBF significantly and increased the number of motile points.

CONCLUSIONS

These data show that NPs, including those found in CSE, mechanically stimulate axonemes in a size- and surface chemistry-dependent manner. Alterations in ciliary motility due to physicochemical properties of NPs may be important for inhalational lung injury and efficient drug delivery of respirable particles.

Nanoparticles in cigarette smoke; real-time undiluted measurements by a scanning mobility particle sizer

Cigarette smoke is a complex mixture of smoke constituents, often characterised by size-resolved particle distributions. Since descriptions of ultrafine particles <50 nm are absent, our aim was to explore the existence of these nanoparticles in fresh and undiluted cigarette smoke. We measured undiluted smoke particles real-time by a scanning mobility particle sizer with Faraday cup electrometer, integrated in our custom-made smoking machine. Cigarettes were smoked by 2 s puffs, 30 s puff intervals and 50 ml puff volume. We tested six different cigarettes (1-10 mg tar per cigarette) at ten particle size-ranges between 6 and 50 nm, and repeated measurements five times. The formation of nanoparticles in fresh cigarette smoke was observed over the entire range between 6 and 50 nm, and reproduced in all cigarettes. The highest mean yield was 8.8 × 10(9) (SD = 1.1 × 10(9)) particles per cigarette at the largest particle size range by high-tar cigarettes. Nanoparticle counts appear to increase with particle size, claimed tar values and blocking of filter ventilation holes, and inversely with butt length. Fresh undiluted cigarette smoke contains large amounts of potentially toxic nanoparticles <50 nm. We recommend to further study nanoparticles in the characterisation of cigarette smoke.

Effect of smoking parameters on the particle size distribution and predicted airway deposition of mainstream cigarette smoke

It is known that puffing conditions such as puff volume, duration, and frequency vary substantially among individual smokers. This study investigates how these parameters affect the particle size distribution and concentration of fresh mainstream cigarette smoke (MCS) and how these changes affect the predicted deposition of MCS particles in a model human respiratory tract. Measurements of the particle size distribution made with an electrical low pressure impactor for a variety of puffing conditions are presented. The average flow rate of the puff is found to be the major factor effecting the measured particle size distribution of the MCS. The results of these measurements were then used as input to a deterministic dosimetry model (MPPD) to estimate the changes in the respiratory tract deposition fraction of smoke particles. The MPPD dosimetry model was modified by incorporating mechanisms involved in respiratory tract deposition of MCS: hygroscopic growth, coagulation, evaporation of semivolatiles, and mixing of the smoke with inhaled dilution air. The addition of these mechanisms to MPPD resulted in reasonable agreement between predicted airway deposition and human smoke retention measurements. The modified MPPD model predicts a modest 10% drop in the total deposition efficiency in a model human respiratory tract as the puff flow rate is increased from 1050 to 3100 ml/min, for a 2-s puff.

[The narghile and its effects on health. Part I: the narghile, general description and properties]

A narghile is a water-pipe used to smoke a tobacco preparation. As the smoker inhales, the tobacco smoke is sucked down from the bowl and then bubbles up through the water into the air of the smoke chamber and then through the hose to the smoker. Its origins are mysterious and controversial. Nevertheless it remains, under different names, an object used regularly by more than one hundred million people in the world. Since the eighties and especially nineties, its consumption has grown significantly and is now considered to be a worldwide epidemic. However, the knowledge about the effects of narghile smoke on health is partial and sometimes contradictory. Indeed, we are witnessing increasing confusion in biomedical studies and scientific debate about its health impact is unresolved. Given this situation, revealing a serious and profound lack of information about the real nature and toxicity of hookah smoke, the authors conducted this two-part study. The first part presents epidemiological data, describes the narghile and the different types of narghile tobacco and exposes the composition of narghile smoke. The second part highlights the lack of reliable data about the detrimental effects of the narghile pipe on health and especially on the cardiopulmonary function.

[Particle size in water pipe smoke]

INTRODUCTION

It is a popular perception that narghile (water pipe) smoking is less harmful to the lungs than cigarettes in both active and passive smokers.

METHODS

Using a sinusoidal pump we simulated water pipe smoking in conditions close to users' habits. The particle sizes and concentrations in the smoke streams were measured with an electrical low pressure impactor (ELPI), sorting particle numbers and size into 12 classes ranging from 0.028 to 10 microm in diameter.

RESULTS

Water pipe smoke contains microparticles and nanoparticles. The main inhaled smoke stream (C1) contains particles in a concentration of 3.55 x 10(6) ml(-1) with a median particle diameter (D50) of 0.34microm before bubbling through water. After bubbling, it retains 1.20 x 10(6) ml(-1) particles with a D50 of 0.27 mm, indicating that 2/3 of the particles are retained in the water, the smallest being trapped the less. Compared with C1, the D50 of the side stream smoke (C2) is smaller (0.11mm) while the D50 of the expired stream (C3) is similar (0.25mm).

CONCLUSION

After bubbling, C1 particle sizes are similar to those measured in cigarette smoke but the volumes inhaled by a water pipe smoker are higher allowing prediction of greater deposition in the respiratory tract than with cigarette smoking.