ABSTRACT
<p><b>OBJECTIVE</b>To investigate in vitro cytotoxicity and oxidative stress response induced by multiwalled carbon nanotubes (MWCNTs).</p><p><b>METHODS</b>Cultured macrophages (murine RAW264.7 cells) and alveolar epithelium cells type II (human A549 lung cells) were exposed to the blank control, DNA salt control, and the MWCNTs suspensions at 2.5, 10, 25, and 100 μg/mL for 24 h. Each treatment was evaluated by cell viability, cytotoxicity and oxidative stress.</p><p><b>RESULTS</b>Overall, both cell lines had similar patterns in response to the cytotoxicity and oxidative stress of MWCNTs. DNA salt treatment showed no change compared to the blank control. In both cell lines, significant changes at the doses of 25 and 100 μg/mL treatments were found in cell viabilities, cytotoxicity, and oxidative stress indexes. The reactive oxygen species (ROS) generation was also found to be significantly higher at the dose of 10 μg/mL treatment, whereas no change was seen in most of the indexes. The ROS generation in both cell lines went up in minutes, reached the climax within an hour and faded down after several hours.</p><p><b>CONCLUSION</b>Exposure to MWCNTs resulted in a dose-dependent cytotoxicity in cultured RAW264.7 cells and A549 cells, that was closely correlated to the increased oxidative stress.</p>
Subject(s)
Animals , Humans , Mice , Cell Culture Techniques , Cell Line , Cell Survival , Dose-Response Relationship, Drug , Lung , Metabolism , Pathology , Macrophages, Alveolar , Metabolism , Pathology , Microscopy, Electron, Scanning , Microscopy, Electron, Transmission , Microscopy, Fluorescence , Nanotubes, Carbon , Chemistry , Toxicity , Oxidative Stress , Reactive Oxygen Species , Metabolism , Surface PropertiesABSTRACT
<p><b>OBJECTIVE</b>To investigate the health effects of 1-bromopropane (1-BP) on female exposed workers.</p><p><b>METHODS</b>Four 1-BP manufacturing plants were investigated. Workers were interviewed with questionnaire and examined with neurobehavioral core test battery, nerve conduction velocity tests of nervus tibialis and nervus suralis, vibration sensation test, hematological and biochemical tests. Ambient 1-BP concentration was measured with detection tube, and time-weighed average levels of individual workers were estimated with passive samplers.</p><p><b>RESULTS</b>1-BP concentration in the plants ranged from 0 to 402.40 mg/m3 (Geomean 32.19 mg/m3). Time-weighted average exposure levels (TWA-8 h) ranged from 0.35 to 535.19 mg/m3 (Geomean 14.08 mg/m3). Compared with the control group, 1-BP exposed workers showed reduced motor nerve conduction velocity [(44.8 +/- 8.7) m/s] and sensory nerve conduction velocity [(45.5 +/- 4.9) m/s], prolonged distal latency [(7.5 +/- 2.1) ms], reduced toe vibration perception, and altered neurobehavior parameters(POMS vigor, tension, anxiety, confusion) significantly (P < 0.05). As to hematological and biochemical indicators, the exposed workers showed decreased white blood cell count [(5.6 +/- 2.17) x 10(3)/microl], red blood cell count [(3.9 +/- 0.4) x 10(6)/microl], hemoglobin [(121.1 +/- 14.5) g/L] and creatine kinase [(82.0 +/- 27.5) IU/L] (P < 0.05), and increased serum total protein (8.0 +/- 0.5 g/dl), lactate dehydrogenase [(335.2 +/- 356.6) IU/L], thyroid-stimulating hormone [(3.6 +/- 2.3) microIU/ml] and follicle-stimulating hormone levels (18.7 +/- 24.4 mIU/ml) (P < 0.05).</p><p><b>CONCLUSION</b>1-BP exposure may affect peripheral nerves and central nervous system, and lead to abnormal hematological and biomedical indicators.</p>
Subject(s)
Adult , Female , Humans , Middle Aged , Young Adult , Creatine Kinase , Metabolism , Hematologic Tests , Hemoglobins , Metabolism , Hydrocarbons, Brominated , Nervous System , Neural Conduction , Occupational ExposureABSTRACT
<p><b>OBJECTIVE</b>To explore the dose-effect relationship between 1-bromopropane (1-BP) exposure and health effects in workers.</p><p><b>METHODS</b>Occupational field investigations were conducted in 1-BP factories. Ambient 1-BP concentrations were detected with detection tube, and the 8 h time-weighted average individual exposure levels (TWA-8 h) were measured by passive sampler. Workers underwent questionnaire survey, neurological examination, nerve conduction velocity examination, vibration sensation test. routine blood test as well as blood biochemical test. According to TWA values or TWA x duration values, workers were divided into three dose groups for dose-effect relationship analysis. USEPA BMDS 2.1 software was applied to calculate 1-BP benchmark dose (BMD) and its 95% lower limit (BMDL).</p><p><b>RESULTS</b>The TWA-8h concentrations ranged from 0.35 to 535.19 mg/m3 (geo-mean 14.08 mg/m3). Dose-dependent analysis showed that the motor nerve distal latency (linear regression coefficient was 0.066 6), vibration sensation of toes (linear regression coefficient were 0.157 2 and 0.193 9), creatine kinase (linear regression coefficient was -1.05) and thyroid stimulating hormone levels (linear regression coefficient was 0.1024) of 1-BP exposed workers changed in a dose-dependent manner (P < 0.05). BMD calculation based on DL as 1-BP toxic effect endpoint showed that TWA-8h of the BMD values and BMDL values were 50.55 mg/m3 and 30.78 mg/m3, respectively.</p><p><b>CONCLUSION</b>1-BP causes dose-dependent changes in tibial nerve DL, vibration sensation, CK and TSH levels.</p>