Cerium oxide nanoparticle uptake kinetics from the gas-phase into lung cells in vitro is transport limited

Nowadays, aerosol processes are widely used for the manufacture of nanoparticles (NPs), creating an increased occupational exposure risk of workers, laboratory personnel and scientists to airborne particles. There is evidence that possible adverse effects are linked with the accumulation of NPs in target cells, pointing out the importance of understanding the kinetics of particle internalization. In this context, the uptake kinetics of representative airborne NPs over 30 min and their internalization after 24 h post-exposure were investigated by the use of a recently established exposure system. This system combines the production of aerosolized cerium oxide (CeO(2)) NPs by flame spray synthesis with its simultaneous particle deposition from the gas-phase onto A549 lung cells, cultivated at the air-liquid interface. Particle uptake was quantified by mass spectrometry after several exposure times (0, 5, 10, 20 and 30 min). Over 35% of the deposited mass was found internalized after 10 min exposure, a value that increased to 60% after 30 min exposure. Following an additional 24 h post-incubation, a time span, after which adverse biological effects were observed in previous experiments, over 80% of total CeO(2) could be detected intracellularly. On the ultrastructural level, focal cerium aggregates were present on the apical surface of A549 cells and could also be localized intracellularly in vesicular structures. The uptake behaviour of aerosolized CeO(2) is in line with observations on cerium suspensions, where particle mass transport was identified as the rate-limiting factor for NP internalization.

A comparison of acute and long-term effects of industrial multiwalled carbon nanotubes on human lung and immune cells in vitro

The close resemblance of carbon nanotubes to asbestos fibers regarding their high aspect ratio, biopersistence and reactivity increases public concerns on the widespread use of these materials. The purpose of this study was not only to address the acute adverse effects of industrially produced multiwalled carbon nanotubes (MWCNTs) on human lung and immune cells in vitro but also to further understand if their accumulation and biopersistence leads to long-term consequences or induces adaptive changes in these cells. In contrast to asbestos fibers, pristine MWCNTs did not induce overt cell death in A549 lung epithelial cells and Jurkat T lymphocytes after acute exposure to high doses of this material (up to 30 g/ml). Nevertheless, very high levels of reactive oxygen species (ROS) and decreased metabolic activity were observed which might affect long-term viability of these cells. However, the continuous presence of low amounts of MWCNTs (0.5 g/ml) for 6 months did not have major adverse long-term effects although large amounts of nanotubes accumulated at least in A549 cells. Moreover, MWCNTs did not appear to induce adaptive mechanisms against particle stress in long-term treated A549 cells. Our study demonstrates that despite the high potential for ROS formation, pristine MWCNTs can accumulate and persist within cells without having major long-term consequences or inducing adaptive mechanisms.

New exposure system to evaluate the toxicity of (scooter) exhaust emissions in lung cells in vitro

A constantly growing number of scooters produce an increasing amount of potentially harmful emissions. Due to their engine technology, two-stroke scooters emit huge amounts of adverse substances, which can induce adverse pulmonary and cardiovascular health effects. The aim of this study was to develop a system to expose a characterized triple cell coculture model of the human epithelial airway barrier, to freshly produced and characterized total scooter exhaust emissions. In exposure chambers, cell cultures were exposed for 1 and 2 h to 1:100 diluted exhaust emissions and in the reference chamber to filtered ambient air, both controlled at 5% CO(2), 85% relative humidity, and 37 degrees C. The postexposure time was 0-24 h. Cytotoxicity, used to validate the exposure system, was significantly increased in exposed cell cultures after 8 h postexposure time. (Pro-) inflammatory chemo- and cytokine concentrations in the medium of exposed cells were significantly higher at the 12 h postexposure time point. It was shown that the described exposure system (with 2 h exposure duration, 8 and 24 h postexposure time, dilution of 1:100, flow of 2 L/min as optimal exposure conditions) can be used to evaluate the toxic potential of total exhaust emissions.

Fluorescent-magnetic hybrid nanoparticles induce a dose-dependent increase in proinflammatory response in lung cells in vitro correlated with intracellular localization

Iron-platinum nanoparticles embedded in a poly(methacrylic acid) (PMA) polymer shell and fluorescently labeled with the dye ATTO 590 (FePt-PMA-ATTO-2%) are investigated in terms of their intracellular localization in lung cells and potential to induce a proinflammatory response dependent on concentration and incubation time. A gold core coated with the same polymer shell (Au-PMA-ATTO-2%) is also included. Using laser scanning and electron microscopy techniques, it is shown that the FePt-PMA-ATTO-2% particles penetrate all three types of cell investigated but to a higher extent in macrophages and dendritic cells than epithelial cells. In both cell types of the defense system but not in epithelial cells, a particle-dose-dependent increase of the cytokine tumor necrosis factor alpha (TNFalpha) is found. By comparing the different nanoparticles and the mere polymer shell, it is shown that the cores combined with the shells are responsible for the induction of proinflammatory effects and not the shells alone. It is concluded that the uptake behavior and the proinflammatory response upon particle exposure are dependent on the time, cell type, and cell culture.

Whole brain radiotherapy with a conformational external beam radiation boost for lung cancer patients with 1-3 brain metastasis: a multi institutional study

To determine the outcome of patients with brain metastasis (BM) from lung cancer treated with an external beam radiotherapy boost (RTB) after whole brain radiotherapy (WBRT).

Effectiveness of nitric oxide during spontaneous breathing in experimental lung injury

Inhaled nitric oxide (iNO) improves gas exchange in about 60% of patients with acute respiratory distress syndrome (ARDS). Recruitment of atelectatic lung areas may improve responsiveness and preservation of spontaneous breathing (SB) may cause recruitment. Accordingly, preservation of SB may improve effectiveness of iNO. To test this hypothesis, iNO was evaluated in experimental acute lung injury (ALI) during SB. In 24 pigs with ALI, effects of 10 ppm iNO were evaluated during controlled mechanical ventilation (CMV) and SB in random order. Preservation of SB was provided by 4 different modes: Unassisted SB was enabled by biphasic positive airway pressure (BIPAP), moderate inspiratory assist was provided by pressure support (PS) and volume-assured pressure support (VAPS), maximum assist was ensured by assist control (A/C). Statistical analysis did not reveal gas exchange improvements due to SB alone. Significant gas exchange improvements due to iNO were only achieved during unassisted SB with BIPAP (P <.05) but not during CMV or assisted SB. The authors conclude that effectiveness of iNO may be improved by unassisted SB during BIPAP but not by assisted SB. Thus combined iNO and unassisted SB is possibly most effective to improve gas exchange in severe hypoxemic ARDS.

The relationship between extravascular lung water and oxygenation in three patients with influenza A (H1N1)-induced respiratory failure

This case series reports the correlation between extravascular lung water (EVLW) and the partial arterial oxygen pressure/fractional inspiratory oxygen (PaO(2)/FiO(2)) ratio in three patients with severe influenza A (H1N1)-induced respiratory failure. All patients suffered from grave hypoxia (PaO(2), 26-42 mmHg) and were mechanically ventilated using biphasic airway pressure (PEEP, 12-15 mmHg; FiO(2), 0.8-1) in combination with prone positioning at 12 hourly intervals. All patients were monitored using the PICCO system for 8-11 days. During mechanical ventilation, a total of 62 simultaneous determinations of the PaO(2)/FiO(2) ratio and EVLW were performed. A significant correlation between EVLW and the PaO(2)/FiO(2) ratio (Spearman-rho correlation coefficient, -0.852; p < 0.001) was observed. In all patients, a decrease in EVLW was accompanied by an improvement in oxygenation. Serum lactate dehydrogenase levels were elevated in all patients and significantly correlated with EVLW during the intensive care unit stay (Spearman-rho correlation coefficient, 0.786; p < 0.001). In conclusion, EVLW seems increased in patients with severe H1N1-induced respiratory failure and appears to be closely correlated with impairments of oxygenatory function.

Src inhibitors in lung cancer: current status and future directions

Src tyrosine kinases regulate multiple genetic and signaling pathways involved in the proliferation, survival, angiogenesis, invasion, and migration of various types of cancer cells They are frequently expressed and activated in many cancer types, including lung cancer. Several Src inhibitors, including dasatinib, saracatinib, bosutinib, and KX2-391, are currently being investigated in clinical trials. Preliminary results of the use of single-agent Src inhibitors in unselected patients with lung cancer show that these inhibitors have a favorable safety profile and anticancer activity. Their combination with cytotoxic chemotherapy, other targeted therapy, and radiation therapy is currently being explored. In this review, we summarize the rationale for and the current status of Src inhibitor development and discuss future directions based on emerging preclinical data.

Lung fluid movements in hypoxia

Pulmonary edema is a problem of major clinical importance resulting from a persistent imbalance between forces that drive water into the airspace of the lung and the biological mechanisms for its removal. Here, we will first review the fundamental mechanisms implicated in the regulation of lung fluid homeostasis, namely, the Starling forces and the respiratory transepithelial sodium transport. Second, we will discuss the contribution of hypoxia to the perturbation of this fine balance and the role of such perturbations in the development of high-altitude pulmonary edema, a disease characterized by a very high morbidity and mortality. Finally, we will review possible interventions aimed to maintain/restore lung fluid homeostasis and their importance for the prevention/treatment of pulmonary edema.

Detection of Merkel cell polyomavirus in epidermodysplasia-verruciformis-associated skin neoplasms

BACKGROUNd: Epidermodysplasia verruciformis (EV) is a rare genodermatosis that is characterized by susceptibility to infection with specific human papillomavirus (HPV) genotypes. Among polyomaviruses, the novel Merkel cell polyomavirus (MCPyV) has been found in different epithelial skin neoplasias.