Preliminary Evaluation of Efficiency of HOV lane Operation on I-40 Eastbound Memphis, Tennessee

This research is a preliminary ealuation of the effectiveness of the High Occupancy Vehicle (HOV) lane along I-40 eastbound Memphis, TN. This HOVlane is operated from 4 p.m. to 6 p.m. during weekdays. Data for the analysis was collected over a two month period in June and July 2011 using standard techniques as well as low cost smart phone apps and consumer grade GPS navigation products. The data collected included hourly volume data, average vehicle occupancy, violation rates, travel times and carbon emissions estimates. The analysis consisted of three methods of measuring effectiveness: increasing person throughput, providing travel time benefits and environmental benefits. To check for statistically significant differences between HOV lane and other GP lanes statistical methods including the two sample t-test and Mann Whitney test were used. a concept of a beffer index was also used to check the travel time reliability for each lane. The result showed that the objective of increasing person throughput is not met for this corridor within Memphis, TN, and recommendations to improve the effectiveness of the HOV lane are presented

Deficiency of the two-pore-domain potassium channel TREK-1 promotes hyperoxia-induced lung injury

Copyright © 2014 by the Society of Critical Care Medicine and Lippincott Williams & Wilkins. Objectives: We previously reported the expression of the twoporedomain K+ channel TREK-1 in lung epithelial cells and proposed a role for this channel in the regulation of alveolar epithelial cytokine secretion. In this study, we focused on investigating the role of TREK-1 in vivo in the development of hyperoxia-induced lung injury. Design: Laboratory animal experiments. Setting: University research laboratory. Subjects: Wild-type and TREK-1-deficient mice. Interventions: Mice were anesthetized and exposed to 1) room air, no mechanical ventilation, 2) 95% hyperoxia for 24 hours, and 3) 95% hyperoxia for 24 hours followed by mechanical ventilation for 4 hours. Measurements and Main Results: Hyperoxia exposure accentuated lung injury in TREK-1-deficient mice but not controls, resulting in increase in lung injury scores, bronchoalveolar lavage fluid cell numbers, and cellular apoptosis and a decrease in quasi-static lung compliance. Exposure to a combination of hyperoxia and injurious mechanical ventilation resulted in further morphological lung damage and increased lung injury scores and bronchoalveolar lavage fluid cell numbers in control but not TREK-1-deficient mice. At baseline and after hyperoxia exposure, bronchoalveolar lavage cytokine levels were unchanged in TREK-1-deficient mice compared with controls. Exposure to hyperoxia and mechanical ventilation resulted in an increase in bronchoalveolar lavage interleukin-6, monocyte chemotactic protein-1, and tumor necrosis factor-á levels in both mouse types, but the increase in interleukin-6 and monocyte chemotactic protein-1 levels was less prominent in TREK-1-deficient mice than in controls. Lung tissue macrophage inflammatory protein-2, keratinocytederived cytokine, and interleukin-1β gene expression was not altered by hyperoxia in TREK-1-deficient mice compared with controls. Furthermore, we show for the first time TREK-1 expression on alveolar macrophages and unimpaired tumor necrosis factor-á secretion from TREK-1-deficient macrophages. Conclusions: TREK-1 deficiency resulted in increased sensitivity of lungs to hyperoxia, but this effect is less prominent if overwhelming injury is induced by the combination of hyperoxia and injurious mechanical ventilation. TREK-1 may constitute a new potential target for the development of novel treatment strategies against hyperoxiainduced lung injury

Pathway-based predictive approaches for non-animal assessment of acute inhalation toxicity

New approaches are needed to assess the effects of inhaled substances on human health. These approaches will be based on mechanisms of toxicity, an understanding of dosimetry, and the use of in silico modeling and in vitro test methods. In order to accelerate wider implementation of such approaches, development of adverse outcome pathways (AOPs) can help identify and address gaps in our understanding of relevant parameters for model input and mechanisms, and optimize non-animal approaches that can be used to investigate key events of toxicity. This paper describes the AOPs and the toolbox of in vitro and in silico models that can be used to assess the key events leading to toxicity following inhalation exposure. Because the optimal testing strategy will vary depending on the substance of interest, here we present a decision tree approach to identify an appropriate non-animal integrated testing strategy that incorporates consideration of a substance's physicochemical properties, relevant mechanisms of toxicity, and available in silico models and in vitro test methods. This decision tree can facilitate standardization of the testing approaches. Case study examples are presented to provide a basis for proof-of-concept testing to illustrate the utility of non-animal approaches to inform hazard identification and risk assessment of humans exposed to inhaled substances

Computational Prediction of Metabolites of Tobacco-Specific Nitrosamines by CYP2A13

A computational approach for the prediction of tobacco-specific nitrosamine (TSNA) metabolites by cytochrome P450s (CYPs) has been developed that currently predicts all of the known CYP2A13 metabolites of nicotine-derived nitrosamine ketone (NNK), N-nitrosonornicotine (NNN), and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) resulting from hydroxylations and heteroatom oxidations reported in metabolomics literature. This computational approach integrates 1) machine learning models trained on quantum-mechanically-derived molecular surface properties for a set of CYP substrates with known metabolites to identify sites of metabolism across CYP isoforms and 2) validation of machine learning predictions using ensemble docking of the TSNA parent molecules into CYP2A13’s binding site to identify the most likely TSNA reactive atoms. This method is generalizable to any CYP isoform for which there is structural information, opening the door to the prediction of P450-based metabolite prediction, as well as prediction and rationalization of metabolomics data.</div

Dynamic Imaging of Airways During Bronchoconstriction and Deep Inspiration in Intact Rats

Airways are continuously subjected to cyclic mechanical stretch during normal respiratory movements, and large distensions occur periodically with deep sighs. However, there is limited information on the levels of mechanical stretch in vivo and how these might change in hyper-responsive airways. Using a unique microfocal X-ray imaging system to visualize airways coated with tantalum dust, we imaged dynamic changes in dimensions of rat airways in vivo following exposure to methacholine during mechanical ventilation. Circumferential strain and longitudinal strain were measured based upon changes in diameter and length of segments during a breath cycle relative to dimensions at end expiration. We simultaneously performed measurements of lung resistance and compliance using the Flexivent system. We found significant changes in the diameters of airways of all sizes (~0.2 mm to 2 mm), but there was substantially more heterogeneity in smaller airways. We also found that a deep inspiration caused significant relaxation of airways circumferentially, but deep inspiration had little effect on longitudinal dimensions. These measurements allow us to quantify changes in the levels of mechanical stretch in airways during bronchoconstriction and to assess the time-dependent response to a deep inspiration

Biomarkers of Exposure and Potential Harm in Two Weeks of Smoking Abstinence: Changes in Biomarkers of Platelet Function, Oxidative Stress, and Inflammation

: Chronic cigarette smoking is a major risk factor for many serious diseases. While complete cessation of smoking is the best option to reduce harm from smoking, adverse impacts of smoking on health could persist for several years after cessation. Therefore, Biomarkers of Potential Harm (BoPH) are useful in interim evaluations of the beneficial effects of smoking cessation or switching to potentially lower-risk tobacco products. A 14-day smoking abstinence study was conducted under clinical confinement conditions and enrolled 70 subjects into younger (24–34 years, n = 33) and older (35–60 years, n = 37) age cohorts. Biomarkers of Exposure (BoE), which indicate exposure to nicotine and other toxicants, were measured at baseline, 7 and 14 days. Several BoPH including previously identified eicosanoids (leukotriene 4 (LTE4) and 2,3-dinor thromboxane 2 (2,3-d-TXB2) and others were evaluated. Significant declines in BoE, LTE4, 2,3-d-TXB2, neutrophils, WBC and select RBC, and arterial blood gas parameters were observed in both age cohorts at Days 7 and 14 compared to baseline, while other BoPH (e.g., FeNO) showed age-related effects. Rapid and reproducible reductions in LTE4, 2,3-d-TXB2 WBC, and neutrophil counts were consistently detected following smoking abstinence, indicating the value of these markers as useful BoPH

Evaluation of Cytotoxicity and Oxidative Stress of Whole Aerosol from Vuse Alto ENDS Products

Assessment of in vitro cytotoxicity is an important component of tobacco product toxicological evaluations. However, current methods of regulatory testing involve exposing monolayer cell cultures to various preparations of aerosols from cigarettes or other emerging products such as electronic nicotine delivery systems (ENDS), which are not representative of human exposure. In the present study, a whole aerosol (WA) system was used to expose lung epithelial cultures (2D and 3D) to determine the potential of six Vuse Alto ENDS products that varied in nicotine content (1.8%, 2.4%, and 5%) and flavors (Golden Tobacco, Rich Tobacco, Menthol, and Mixed Berry), along with a marketed ENDS and a marked cigarette comparator to induce cytotoxicity and oxidative stress. The WA from the Vuse Alto ENDS products was not cytotoxic in the NRU and MTT assays, nor did it activate the Nrf2 reporter gene, a marker of oxidative stress. In summary, Vuse Alto ENDS products did not induce cytotoxic or oxidative stress responses in the in vitro models. The WA exposures used in the 3D in vitro models described herein may be better suited than 2D models for the determination of cytotoxicity and other in vitro functional endpoints and represent alternative models for regulatory evaluation of tobacco products

Preexposure to hyperoxia causes increased lung injury and epithelial apoptosis in mice ventilated with high tidal volumes

Both high tidal volume mechanical ventilation (HV) and hyperoxia (HO) have been implicated in ventilator-induced lung injury. However, patients with acute lung injury are often exposed to HO before the application of mechanical ventilation. The potential priming of the lungs for subsequent injury by exposure to HO has not been extensively studied. We provide evidence that HO (90%) for 12 h followed by HV (25 μl/g) combined with HO for 2 or 4 h (HO-12h+HVHO-2h or -4h) induced severe lung injury in mice. Analysis of lung homogenates showed that lung injury was associated with cleavage of executioner caspases, caspases-3 and -7, and their downstream substrate poly(ADP-ribose) polymerase-1 (PARP-1). No significant lung injury or caspase cleavage was seen with either HO for 16 h or HV for up to 4 h. Ventilation for 4 h with HO (HVHO) did not cause significant lung injury without preexposure to HO. Twelve-hour HO followed by lower tidal volume (6 μl/g) mechanical ventilation failed to produce significant injury or caspase cleavage. We also evaluated the initiator caspases, caspases-8 and -9, to determine whether the death receptor or mitochondrial-mediated pathways were involved. Caspase-9 cleavage was observed in HO-12h+HVHO-2h and -4h as well as HO for 16 h. Caspase-8 activation was observed only in HO-12h+HVHO-4h, indicating the involvement of both pathways. Immunohistochemistry and in vitro stretch studies showed caspase cleavage in alveolar epithelial cells. In conclusion, preexposure to HO followed by HV produced severe lung injury associated with alveolar epithelial cell apoptosis