Cell culture techniques essential for toxicity testing of inhaled materials and nanomaterials in vitro

Human tissue is bombarded by a huge range of chemicals. Our lungs are inhaling pollution from both stationary and mobile sources as well as inhaled nanoparticles (NPs) and therapeutic products designed to provide new and innovative medical solutions. Our challenge is to identify what exposures are putting us at risk and balance the risk against benefits that we may receive from these chemicals and new products. Advances inin vitrocell culture technology may provide some of the answers. Regulatory toxicologists and health and safety professionals need rapid and reliable information on hazard profiles of chemicals to be able to assess the risk and manage potential exposures to harmful materials. in vivo studies require a large number of expensive, time consuming and in some cases non humane tests in animal species. Recent innovations in human cell culture exposure and test systems has allowed the development ofin vitro assay systems that are predictive, representative and suitable for toxicity screening of a diverse range of chemicals including airborne materials and nanomaterials (NMs). Innovative in vitro exposure techniques that have been developed to provide direct exposure of human lung cells to inhaled materials and nanomaterials will be discussed. Further development and validation of such test systems are crucial for evidence based safety evaluation and risk assessment of inhaled materials, nanomaterials and therapeutic products

Air pollution effects on the activity of antioxidant enzymes in Nerium oleander and Robinia pseudo acacia plants in Tehran

The air pollution effects on the activity of antioxidant enzymes were investigated on Nerium oleander and Robinla pseudo acacia in Tehran. Considering the information obtained from the Department of the Environment of Iran, Sorkh Hesar Park as well as South Azadi were selected as two sampling sites representing the unpolluted and polluted area respectively. A number of plant leave samples were collected from both sampling sites simultaneously. The activity of plant enzymes including peroxidase, catalase and ascorbate peroxidase was investigated using spectrophotometric methods. A higher level of peroxidase and catalase enzymes were measured in both plant samples collected from polluted area. However, this higher level was only statistically significant for the activity of peroxidase enzyme in Robinia pseudo acacia plants compare of to the control group (p < 0.05). The lower level of ascorbate peroxidase was observed in Nerium oleander plant leaves collected from the contaminated sampling site (p < 0.05), but though, the activity of this enzyme in Robinia pseudo acacia did not change significantly. The overall plant injury symptoms found in this study demonstrated that both Nerium oleander and Robinia pseudo acacia have a potential to be considered as effective bioindicators to reflect the environmental air quality in polluted areas

The Prevalence of Needle sticks injuries among health care workers at a hospital in Tehran

ABSTRACT Needle stick injuries (NSIs) are one of the most significant and preventable hazards in relation to Healthcare workers (HCWs). Such injuries have been shown to be of high prevalence within developing countries. To determine the prevalence and circumstances pertaining to the occurrence of NSIs among HCWs employed at a special hospital. The study conducted was a cross-sectional study on HCWs and was carried out in one of Tehran's special hospitals in the year 2012. In this study, in order to identify and determine hazardous potential due to needle stick, HFMEA method was chosen. This resulted in the collection of 240 valid and reliable questionnaires. The validity and reliable nature of the questionnaires was confirmed by experts and by means of the test re-test method. The gathered data was analyzed with SPSS software, version 16.From the analysis of the data it was shown that, a total of 97 (40.42%) HCWs had suffered NSIs in the last year. The patient ward showed the highest prevalence of NSIs (47.42%) in the hospital. Nurses had the highest risk of suffering NSIs (56.7%) in comparison with the other occupational groups. All in all 175 NSIs occurred for the 240 HCWs trialed during the selected period of clinical practice. Of those that received injuries, only roughly 1 in 3 (38.14%) reported it to their infection control officer. Just over a quarter (26.80%) of the injured HCWs used post exposure prophylaxis (PEP) against HIV. Almost all (88.75%) of the HCWs had received a safe injection course. In general, NSIs and their subsequent underreporting are commonplace among hospital healthcare professionals. Significantly, more than two-thirds of the injured HCWs did not use post-exposure prophylaxis (PEP) against HIV. Improved prevention and reporting strategies are needed if the occupational health and safety of healthcare workers is to improve

An integrated in vitro approach for toxicity testing of airborne contaminants

While it is possible to establish the chemical composition of air pollutants through conventional air sampling and analytical techniques, such data do not provide direct measures of toxicity and the potential mechanisms that induce adverse effects. The aim of this study was to optimize in vitro methods for toxicity testing of airborne contaminants. An integrated approach was designed in which appropriate exposure techniques were developed. A diversified range of in vitro assays using multiple human cell systems were implemented. Direct exposure of cells to airborne contaminants was developed by culturing cells on porous membranes in conjunction with a horizontal diffusion chamber system. Concentration-response curves were generated allowing the measurement of toxicity endpoints. Regression analysis indicated a significant correlation between in vitro and published in vivo toxicity data for the majority of selected chemical contaminants. Airborne IC50 values were calculated for selected volatile organic compounds (xylene, 5350 ± 328 ppm > toluene, 10500 ± 527 ppm) and gaseous contaminants (NO2, 11 ± 3.54 ppm > SO2, 48 ± 2.83 ppm and > NH3, 199 ± 1.41 ppm). Results of this study indicate the significant potential of in vitro methods as an advanced technology for toxicity assessment of airborne contaminants. Copyright © Taylor & Francis Group, LLC

Comparative in vitro cytotoxicity assessment of selected gaseous compounds in human alveolar epithelial cells

Exposure to airborne contaminants is significantly associated with human health risks, ranging from bronchial reactivity to morbidity and mortality due to acute intense or long term low level repeated exposures. However, the precise mechanisms that derive such effects are not always understood. Although inhalation studies are technologically complicated, correct hazard characterisation is essential for comparable risk assessment of inhaled materials. The aim of this study was to investigate the comparative in vitro cytotoxicity of selected gaseous contaminants in human lung cells. The cytotoxicity of nitrogen dioxide (NO2), sulphur dioxide (SO2) and ammonia (NH3) was investigated in A549- human pulmonary type II-like epithelial cell lines cultured on porous membranes in Snapwell inserts. A dynamic direct exposure method was established by utilizing the horizontal diffusion chamber system (Harvard Apparatus Inc, USA) for delivery of test atmospheres. Test atmospheres were generated using a dynamic direct dilution method and the concentration monitored by appropriate analytical methods. A diversified battery of in vitro assays including the MTS (tetrazolium salt; Promega), NRU (neutral red uptake; Sigma) and ATP (adenosine triphosphate; Promega) assays was implemented. Airborne IC50 (50 inhibitory concentration) values were calculated based on the most sensitive assay for each test gas including NO2 (IC50 = 11 ± 3.54 ppm; NRU) &gt; SO2 (IC50 = 48 ± 2.83 ppm; ATP)&gt; and NH3 (IC50 = 199 ± 1.41 ppm; MTS). However, all in vitro assays revealed similar toxicity ranking for selected gaseous contaminants. Identical toxicity ranking was achieved using both in vitro and published in vivo data. This comparison suggests that results of in vitro methods are comparable to in vivo data and may provide greater sensitivity for respiratory toxicity studies of gaseous contaminants. © 2007 Elsevier Ltd. All rights reserved