Comparing the quality of ChatGPT- and physician-generated responses to patients' dermatology questions in the electronic medical record.

BACKGROUND: ChatGPT is a free artificial intelligence (AI)-based natural language processing tool that generates complex responses to inputs from users. OBJECTIVES: To determine whether ChatGPT is able to generate high-quality responses to patient-submitted questions in the patient portal. METHODS: Patient-submitted questions and the corresponding responses from their dermatology physician were extracted from the electronic medical record for analysis. The questions were input into ChatGPT (version 3.5) and the outputs extracted for analysis, with manual removal of verbiage pertaining to ChatGPT's inability to provide medical advice. Ten blinded reviewers (seven physicians and three nonphysicians) rated and selected their preference in terms of 'overall quality', 'readability', 'accuracy', 'thoroughness' and 'level of empathy' of the physician- and ChatGPT-generated responses. RESULTS: Thirty-one messages and responses were analysed. Physician-generated responses were vastly preferred over the ChatGPT -responses by the physician and nonphysician reviewers and received significantly higher ratings for 'readability' and 'level of empathy'. CONCLUSIONS: The results of this study suggest that physician-generated responses to patients' portal messages are still preferred over ChatGPT, but generative AI tools may be helpful in generating the first drafts of responses and providing information on education resources for patients.

Prevalence and clinical presentation of EV-D68 infections in Kansas City children during the 2022 season.

Seasonal EV-D68 infections can strain medical care resources due to increased pediatric hospitalizations for respiratory illness. In this study, we examine Kansas City's 2022 EV-D68 season. Rhinovirus/enterovirus (RV/EV) positive respiratory specimens from standard of care testing were salvaged and tested by EV-D68 specific PCR. Of the 1412 respiratory specimens tested from July 1 to September 15, 2022, 346 (23%) were positive for RV/EV and EV-D68 was detected in 134/319 (42%) salvaged RV/EV positive specimens. The median age of children with EV-D68 infections was 35.2 months (IQR 16.1, 67.3), which was older than children with non-EV-D68 RV/EV infections (16 months, IQR 5, 47.8), but younger than children infected during the 2014 EV-D68 outbreak. EV-D68 infection was more likely to cause severe disease in children with asthma compared to those without asthma. Real-time EV-D68 monitoring for outbreaks could potentially improve resource utilization by hospitals and help prepare for surges of respiratory disease.

Chemiluminescent Measurement of Hydrogen Peroxide in the Exhaled Breath Condensate of Healthy and Asthmatic Adults.

Reactive oxygen species are centrally involved in the pathophysiology of airway diseases such as asthma and chronic obstructive pulmonary disease. This study reports the development of a chemiluminescence assay and a device for measuring hydrogen peroxide in the exhaled breath condensate of asthma patients and healthy participants. A stand-alone photon detection device was constructed for use with an optimized chemiluminescence assay. Calibrations using a catalase control to scavenge residual hydrogen peroxide in calibrant solutions provided analytically sensitive and specific measurements. We evaluated exhaled breath condensate hydrogen peroxide in 60 patients (ages 20-83; 30 healthy patients and 30 asthma patients) recruited from the John Peter Smith Hospital Network. The exhaled breath condensate hydrogen peroxide concentrations trended toward higher values in asthma patients compared to healthy participants (mean 142.5 vs 115.5 nM; p = 0.32). Asthma patients who had not used an albuterol rescue inhaler in the past week were compared to those who had and showed a trend toward higher hydrogen peroxide levels (mean 172.8 vs 115.9 nM; p = 0.25), and these patients also trended toward higher hydrogen peroxide than healthy participants (mean 172.8 vs 115.5 nM; p = 0.14). This pilot study demonstrates the ability of the newly developed assay and device to measure exhaled breath condensate hydrogen peroxide in asthma patients and healthy participants. The trends observed in this study are in agreement with previous literature and warrant further investigation of using this system to measure exhaled breath condensate hydrogen peroxide for monitoring oxidative stress in asthma.

Viability of tDCS in Military Environments for Performance Enhancement: A Systematic Review.

INTRODUCTION: Transcranial electrical stimulation (tES) as a method of cognitive enhancement in both diseased and healthy individuals has gained popularity. Its potential for enhancing cognition in healthy individuals has gained the interest of the military. However, before it being implemented into military training or operational settings, further work is needed to determine its efficacy and safety. Although a considerable amount of literature exists, few studies have specifically evaluated its use in enhancing cognition relative to operational, military tasks. Therefore, in a first step to evaluate its efficacy, we completed a systematic literature review of studies using transcranial direct current stimulation (tDCS), a type of tES, to enhance cognitive processes in healthy individuals. METHODS: A systematic literature review was conducted to identify literature published between 2008 and 2018 that used a method of tES for cognitive enhancement. As part of a larger literature review effort, 282 articles were initially retrieved. These were then screened to identify articles meeting predetermined criteria, to include those using various methods of tES, resulting in 44 articles. Next, the articles were screened for those using tDCS or high-definition tDCS, resulting in 34 articles for review and information extraction. RESULTS: Of the 34 articles reviewed, 28 reported some degree of enhancement (eg, improved accuracy on tasks and reduced reaction times). Areas of cognitive enhancements included executive functioning, creativity/cognitive flexibility, attention/perception, decision-making, memory, and working memory. However, the precise outcomes of enhancement varied given the range in tasks that were used to assess the constructs. Additionally, the stimulation parameters in terms of intensity applied, duration of stimulation, and brain region targeted for stimulation varied. CONCLUSIONS: The conclusions to be drawn from this systematic literature review include the identification of a brain region for targeting with stimulation to enhance a broad range of cognitive constructs applicable to military tasks, as well as stimulation parameters for duration and intensity. The dorsolateral prefrontal cortex was most frequently targeted in the studies that found enhanced performance across several cognitive constructs. Stimulation intensities of 2 mA and durations of 20 minutes or longer appeared frequently as well. Although several parameters were identified, further work is required before this type of technology can be recommended for operational use.

Sodium halides as the source of electrophilic halogens in green synthesis of 3-halo- and 3,n-dihalobenzo[b]thiophenes.

A convenient methodology for the synthesis of mono- and di-halogenated benzo[b]thiophenes is described herein, which utilizes copper(II) sulfate pentahydrate and various sodium halides in the presence of substituted 2-alkynylthioanisoles. The proposed method is facile, uses ethanol as a green solvent, and results in uniquely substituted benzo[b]thiophene structures with isolated yields up to 96%. The most useful component of this methodology is the selective introduction of bromine atoms at every available position (2-7) around the benzo[b]thiophene ring, while keeping position 3 occupied by a specific halogen atom such as Cl, Br or I. Aromatic halogens are useful reactive handles; therefore, the selective introduction of halogens at specific positions would be valuable in the targeted synthesis of bioactive molecules and complex organic materials via metal-catalyzed cross coupling reactions. This work is a novel approach towards the synthesis of dihalo substituted benzo[b]thiophene core structures, which provides a superior alternative to the current methods discussed herein.

The Influence of Combat Experience on Psychologically Healthy Soldiers' Attentiveness to Environmental Threats.

INTRODUCTION: In contrast to previous research that has primarily examined how psychological disorders (e.g., post-traumatic stress disorder [PTSD], anxiety) are affected by and affect individuals' threat perceptions, this study examines the relationship between combat experience and threat-monitoring in psychologically healthy Soldiers. Existing research has established how prolonged or intense experiences with war-related stressors can lead individuals to undergo an unconscious fear-conditioning process that affects the circuitry of the prefrontal cortex, hippocampus, amygdala, and anterior cingulate cortex regions of the brain. We predict that the intensity of one's combat experience positively influences Soldiers' attention to environmental threats. MATERIALS AND METHODS: Participants included U. S. Army Soldiers with a score of 50 or below on the PTSD Checklist-Military Version. Participants completed the Combat Exposure Scale and the State-Trait Anxiety Inventory. The experimental prediction task we employed assesses the expectation of an intrusively loud white noise sound that occurred on three variable patterns in a pseudorandomized order. Each tone pattern was used 20 times over a total of 60 trials. The experimental prediction task included two neutral tones (700 and 1,300 Hz) that were presented in a repeated pattern along with a 100-dB burst of white noise (0.5-second duration). In each trial, one of three possible tone combinations was presented. To assess their attentiveness to threats, participants were asked to continuously rate their expectancy of the burst of white noise using a visual analogue scale (VAS) ranging from 0 to 100. VAS ratings were collected at controlled points throughout the task. RESULTS: None of the participants reported scores on any of the diagnostic surveys that met standards for clinical significance. A repeated-measures analysis of variance was conducted to assess the overall effect of the three prediction conditions on participants' VAS ratings. There was a significant main effect for Combat Exposure Scale scores on VAS ratings [F(1, 27) = 5.19, p = 0.031], with high scorers demonstrating a generally higher expectancy of the white noise burst throughout the entire experimental sequence. Results suggest that within subclinical populations of Soldiers, the intensity of one's combat experience is positively associated with their attention to threats. CONCLUSION: These findings suggest that Soldiers who experience combat should be observed for signs of increased threat-attention bias, as this may indicate that their capacities for information processing, decision-making, and emotion regulation could be compromised. The positive relationship we observe between a level of combat experience and attentional biases toward threatening stimuli may also help to explain why these veterans engage in "externalizing" behaviors that are risky, aggressive, or violent as well as relational problems and antisocial behaviors that are reported in higher-than-average rates among these populations of Soldiers. Acknowledging that increased threat attention may be a preclinical indication of developing PTSD or other related psychological conditions (e.g., depression, anxiety) should motivate clinicians to more actively diagnose and treat this condition.

Poor expectations of knee replacement benefit are associated with modifiable psychological factors and influence the decision to have surgery: A cross-sectional and longitudinal study of a community-based sample.

BACKGROUND: Total knee arthroplasty (TKA) is a highly effective surgery, but is underutilized by some patient groups. This study determined factors associated with a person's expectations with respect to pain and walking function following a TKA procedure, should they elect to undergo a TKA. METHODS: A total of 3542 people were studied with or at risk of knee osteoarthritis and enrolled in the community-based Osteoarthritis Initiative (OAI). Multivariable logistic regression analyses identified demographic, socioeconomic, osteoarthritis-related, joint replacement awareness, and psychological correlates as poor outcome expectations. Logistic regression determined if outcome expectation was associated with future knee arthroplasty utilization. RESULTS: Approximately 25% of the sample expected a poor outcome. Several factors were associated with poor pain outcome expectation, with the most powerful being African American race (Odds Ratio (OR)=2.11, 95% CI=1.69, 2.64) and an interaction between clinical depression symptoms and pain catastrophizing (OR=3.17, 95% CI=2.26, 4.44 when both were coded 'yes'). Whether a person had knee OA did not affect expectations. Pain outcome expectations were strongly associated with future TKA utilization (OR=4.9, 95% CI=2.2, 11.1). CONCLUSION: A variety of modifiable psychological factors impact people's expectations of the extent of pain and walking difficulty following a potential future TKA. Expectations strongly predict future TKA utilization. Given the high prevalence of knee osteoarthritis, mass media educational interventions for the population may assist in better aligning expectations with evidence-based knee arthroplasty outcomes and lead to more appropriate utilization of an effective procedure.

Toxicological Considerations, Toxicity Assessment, and Risk Management of Inhaled Nanoparticles.

Novel engineered nanoparticles (NPs), nanomaterial (NM) products and composites, are continually emerging worldwide. Many potential benefits are expected from their commercial applications; however, these benefits should always be balanced against risks. Potential toxic effects of NM exposure have been highlighted, but, as there is a lack of understanding about potential interactions of nanomaterials (NMs) with biological systems, these side effects are often ignored. NPs are able to translocate to the bloodstream, cross body membrane barriers effectively, and affect organs and tissues at cellular and molecular levels. NPs may pass the blood-brain barrier (BBB) and gain access to the brain. The interactions of NPs with biological milieu and resulted toxic effects are significantly associated with their small size distribution, large surface area to mass ratio (SA/MR), and surface characteristics. NMs are able to cross tissue and cell membranes, enter into cellular compartments, and cause cellular injury as well as toxicity. The extremely large SA/MR of NPs is also available to undergo reactions. An increased surface area of the identical chemical will increase surface reactivity, adsorption properties, and potential toxicity. This review explores biological pathways of NPs, their toxic potential, and underlying mechanisms responsible for such toxic effects. The necessity of toxicological risk assessment to human health should be emphasised as an integral part of NM design and manufacture.

A cybercycling intervention to improve behavioral regulation and classroom functioning among children with behavioral health disorders: Pragmatic randomized trial design for Manville Moves.

While positive and clinically meaningful effects of exercise on cognition and behavior in children have been demonstrated in controlled experimental settings, they have rarely been translated and rigorously evaluated in real-world environments. In particular, there is a lack of research on school-based approaches to sustainable physical activity and exercise interventions targeting children with behavioral health disorders. Manville Moves is an exercise intervention designed to improve behavioral regulation and classroom functioning among children with neurodevelopmental and affective disorders within a therapeutic day-school environment. The curriculum is built around virtual-reality exergaming bicycles (cybercycles) and integrated into physical education (PE) classes. Manville Moves was developed using community based participatory research (CBPR) and implemented as a pragmatic trial. In this paper, we describe (a) the background, theoretical framework and intervention setting, (b) the Manville Moves curriculum, (c) the study design and outcome and process measures, and (d) the strategies used to support implementation compliance and intervention uptake by a population with a variety of behavioral challenges. We conclude with a detailed description of the participatory process by which the intervention was developed and integrated into school programming and a review of the program's key innovations and approaches to addressing threats to internal and external validity.

The role of the speech-language pathologist in home care.

Speech language pathologists play an important role in the care of patients with speech, language, or swallowing difficulties that can result from a variety of medical conditions. This article describes how speech language pathologists assess and treat these conditions and the red flags that suggest a referral to a speech language pathologist is indicated.

Toxicological perspectives of inhaled therapeutics and nanoparticles.

INTRODUCTION: The human respiratory system is an important route for the entry of inhaled therapeutics into the body to treat diseases. Inhaled materials may consist of gases, vapours, aerosols and particulates. In all cases, assessing the toxicological effect of inhaled therapeutics has many challenges. AREAS COVERED: This article provides an overview of in vivo and in vitro models for testing the toxicity of inhaled therapeutics and nanoparticles implemented in drug delivery. Traditionally, inhalation toxicity has been performed on test animals to identify the median lethal concentration of airborne materials. Later maximum tolerable concentration denoted by LC0 has been introduced as a more ethically acceptable end point. More recently, in vitro methods have been developed, allowing the direct exposure of airborne material to cultured human target cells on permeable porous membranes at the air-liquid interface. EXPERT OPINION: Modifications of current inhalation therapies, new pulmonary medications for respiratory diseases and implementation of the respiratory tract for systemic drug delivery are providing new challenges when conducting well-designed inhalation toxicology studies. In particular, the area of nanoparticles and nanocarriers is of critical toxicological concern. There is a need to develop toxicological test models, which characterise the toxic response and cellular interaction between inhaled particles and the respiratory system.

Treatment of obstructive sleep apnea alters cancer-associated transcriptional signatures in circulating leukocytes.

RATIONALE: Obstructive sleep apnea (OSA) has been associated with a number of chronic disorders that may improve with effective therapy. However, the molecular pathways affected by continuous positive airway pressure (CPAP) treatment are largely unknown. We sought to assess the system-wide consequences of CPAP therapy by transcriptionally profiling peripheral blood leukocytes (PBLs). METHODS: Subjects in whom severe OSA was diagnosed were treated with CPAP, and whole-genome expression measurement of PBLs was performed at baseline and following therapy. We used gene set enrichment analysis (GSEA) to identify pathways that were differentially enriched. Network analysis was then applied to highlight key drivers of processes influenced by CPAP. RESULTS: Eighteen subjects with significant OSA underwent CPAP therapy and microarray analysis of their PBLs. Treatment with CPAP improved apnea-hypopnea index (AHI), daytime sleepiness, and blood pressure, but did not affect anthropometric measures. GSEA revealed a number of enriched gene sets, many of which were involved in neoplastic processes and displayed downregulated expression patterns in response to CPAP. Network analysis identified several densely connected genes that are important modulators of cancer and tumor growth. CONCLUSIONS: Effective therapy of OSA with CPAP is associated with alterations in circulating leukocyte gene expression. Functional enrichment and network analyses highlighted transcriptional suppression in cancer-related pathways, suggesting potentially novel mechanisms linking OSA with neoplastic signatures.

Validation of the dynamic direct exposure method for toxicity testing of diesel exhaust in vitro.

Diesel exhaust emission is a major health concern because of the complex nature of its gaseous content (e.g., NO2, NO, CO, and CO2) and high concentration of particulate matter (PM) less than 2.5 µ m which allows for deeper penetration into the human pulmonary system upon inhalation. The aim of this research was to elucidate the potential toxic effects of diesel exhaust on a human pulmonary-based cellular system. Validation of a dynamic direct exposure method for both laboratory (230 hp Volvo truck engine) and field (Volkswagen Passat passenger car) diesel engines, at idle mode, was implemented. Human pulmonary type II epithelial cells (A549) grown on porous membranes were exposed to unmodified diesel exhaust at a low flow rate (37.5 mL/min). In parallel, diesel emission sampling was also conducted using real-time air monitoring techniques. Induced cellular effects were assessed using a range of in vitro cytotoxicity assays (MTS, ATP, and NRU). Reduction of cell viability was observed in a time-dependent manner following 30-60 mins of exposure with NRU as the most sensitive assay. The results suggest that the dynamic direct exposure method has the potential to be implemented for both laboratory- and field-based in vitro toxicity studies of diesel exhaust emissions.

A pathway-based analysis on the effects of obstructive sleep apnea in modulating visceral fat transcriptome.

RATIONALE: Obstructive sleep apnea (OSA) has been associated with metabolic dysregulation and systemic inflammation. This may be due to pathophysiologic effects of OSA on visceral adipose tissue. We sought to assess the transcriptional consequences of OSA on adipocytes by utilizing pathway-focused analyses. METHODS: Patients scheduled to undergo ventral hernia repair surgery were recruited to wear a portable home sleep monitor for 2 nights prior to surgery. Visceral fat biopsies were obtained intraoperatively. RNA was extracted and whole-genome expression profiling was performed. Gene Set Enrichment Analysis (GSEA) was used to identify curated gene sets that were differentially enriched in OSA subjects. Network analysis was applied to a select set of highly enriched pathways. RESULTS: Ten patients with OSA and 8 control subjects were recruited. There were no differences in age, gender, or body mass index between the 2 groups, but the OSA subjects had a significantly higher respiratory disturbance index (19.2 vs. 0.6, P = 0.05) and worse hypoxemia (minimum oxygen saturation 79.7% vs. 87.8%, P < 0.001). GSEA identified a number of gene sets up-regulated in adipose tissue of OSA patients, including the pro-inflammatory NF-κB pathway and the proteolytic ubiquitin/proteasome module. A critical metabolic pathway, the peroxisome proliferator-activated receptor (PPAR), was down-regulated in subjects with OSA. Network analysis linked members of these modules together and identified regulatory hubs. CONCLUSIONS: OSA is associated with alterations in visceral fat gene expression. Pathway-based network analysis highlighted perturbations in several key pathways whose coordinated interactions may contribute to the metabolic dysregulation observed in this complex disorder.

Snake modulates constriction in response to prey's heartbeat.

Many species of snakes use constriction-the act of applying pressure via loops of their trunk-to subdue and kill their prey. Constriction is costly and snakes must therefore constrict their prey just long enough to ensure death. However, it remains unknown how snakes determine when their prey is dead. Here, we demonstrate that boas (Boa constrictor) have the remarkable ability to detect a heartbeat in their prey and, based on this signal, modify the pressure and duration of constriction accordingly. We monitored pressure generated by snakes as they struck and constricted warm cadaveric rats instrumented with a simulated heart. Snakes responded to the beating heart by constricting longer and with greater total pressure than when constricting rats with no heartbeat. When the heart was stopped midway through the constriction, snakes abandoned constriction shortly after the heartbeat ceased. Furthermore, snakes naive to live prey also responded to the simulated heart, suggesting that this behaviour is at least partly innate. These results are an example of how snakes integrate physiological cues from their prey to modulate a complex and ancient behavioural pattern.

Nanoparticles: a review of particle toxicology following inhalation exposure.

It is expected that the rapid expansion of nanotechnology will bring many potential benefits. However, initial investigations have demonstrated that nanomaterials may adversely affect human health and the environment. By increasing the application of nanoparticles, protection of the human respiratory system from exposure to airborne nanoparticles and ultrafine particulates has become an emerging health concern. Available research has demonstrated an association between exposure to ambient airborne particulates and ultrafine particles and various adverse heath effects including increased morbidity and mortality. Nanomaterial structures are more likely to be toxic than the same materials of conventional sized samples and can be inhaled more deeply into the lungs. While the respiratory tract is considered as the primary target organ for inhaled nanoparticles, recent research has demonstrated that extrapulmonary organs are also affected. The very small size distribution and large surface area of nanoparticles available to undergo reactions may play a significant role in nanotoxicity, yet very little is known about their interactions with biological systems. This review explores the possible underlying toxicity mechanisms of nanoparticles following inhalational exposure. Nanoparticles differ from the same conventional material at a larger scale in physical, chemical and biological characteristics; therefore it is critical to recognize the potential risk of nanoparticle exposure using appropriate toxicity test methods. Current advances and limitations of toxicity assessment methods of nanoparticles are discussed highlighting the recent improvements of in vitro screening tools for the safety evaluation of the rapidly expanding area of nanotechnology.

Clinical presentation of shift workers to a sleep clinic.

PURPOSE: The purpose of this study was to assess the relationship between shift work (SW) history and symptom severity in a sleep clinic population. METHODS: A retrospective chart review of 1,275 employed adult patients referred to a sleep disorders clinic was performed. Patients were categorized as working day shift, fixed evening or night shift, or rotating shifts. Sleep-related symptoms were assessed across three domains-sleepiness, insomnia, and apnea-related symptoms. RESULTS: The distribution of work shift was 69% day shift, 8% fixed evening or night shift, and 23% rotating shifts. In general, sleepiness and insomnia symptoms were greatest in fixed shift workers. In analyses adjusted for age, sex, education, race, BMI, habitual sleep duration, marital status, education level, alcohol intake, and smoking history, fixed shift workers were 4.8 times (95% CI, 1.9-12.5) more likely to report sleep onset difficulties, 3.3 times (95% CI, 1.2-9.1) more likely to report excessive caffeine intake, and 1.8 times (95% CI, 1.1-3.0) more likely to report drowsy driving as compared to day shift workers. In contrast, rotating shift workers reported more difficulty with sleep onset (OR 2.7; 95% CI, 1.3-5.6) relative to day shift workers. No relationship between work shift and apnea-related symptoms was identified. CONCLUSIONS: Among patients referred to a sleep disorders clinic, shift workers and in particular fixed shift workers have greater difficulties with sleep onset, drowsy driving, and excessive caffeine intake. Given the presence of effective treatments for SW-related sleep symptoms, these findings suggest an underutilization of sleep medicine specialists for the care of patients with symptoms related to SW.

Sleep duration and circulating adipokine levels.

INTRODUCTION: Short sleep duration is associated with systemic inflammation and diabetes; however the mechanisms by which reduced sleep leads to these complications are unclear. One possibility is sleep may impact secretion of adipocyte derived hormones that regulate inflammation and insulin resistance. In this study we assessed the association between sleep duration and 3 adipokine levels. METHODS: A total of 561 adults from the Cleveland Family Study underwent standardized laboratory polysomnography followed by a morning fasting blood draw assayed for leptin, visfatin, and retinol binding protein-4 (RBP4) levels. RESULTS: The cohort had an age of 44.5 (16.1) years and total sleep time (TST) of 6.2 (1.3) hours (mean [SD]). Each hour reduction in TST was associated with a 10% increase in leptin (P = 0.01) and a 14% increase in visfatin levels (P = 0.03) in analyses adjusted for age, gender, and race. After additional adjustment for obesity, sleep apnea severity, hypertension, and diabetes, each hour reduction in TST was associated with a 6% increase in leptin (P = 0.01) and a 14% increase in visfatin levels (P = 0.02). Leptin increased by 15% (P = 0.01) and visfatin increased by 31% (P = 0.05) for every 1-h decrease in REM sleep. In contrast, no association between sleep duration and RBP4 was found. CONCLUSIONS: Reduced sleep and reduced REM sleep are associated with elevations in leptin and visfatin, 2 adipokines associated with inflammation and insulin resistance. Further investigation of the effect of sleep on adipose tissue function should be pursued.

Inhalation toxicology.

Inhalation of gases, vapors and aerosols can cause a wide range of adverse health effects, ranging from simple irritation to systemic diseases. The large number of chemicals and complex mixtures present in indoor and outdoor air coupled with the introduction of new materials such as nanoparticles and nanofibers, is an area of growing concern for human health. Animal-based assays have been used to study the toxic effects of chemicals for many years. However, even so, very little is known about the potential toxicity of the vast majority of inhaled chemicals. As well as new or refined OECD test guidelines, continuing scientific developments are needed to improve the process of safety evaluation for the vast number of chemicals and inhaled materials. Although studying the toxic effects of inhaled chemicals is more challenging, promising in vitro exposure techniques have been recently developed that offer new possibilities to test biological activities of inhaled chemicals under biphasic conditions at the air liquid interface. This chapter gives an overview of inhalation toxicology as well as focusing on the potential application of in vitro methods for toxicity testing of airborne pollutants.