Showing papers by "Pilje Kim published in 2012"

Toxicity of Citrate-Capped Silver Nanoparticles in Common Carp (Cyprinus carpio)

Abstract: Juvenile common carp (Cyprinus carpio) were used as a model to investigate acute toxicity and oxidative stress caused by silver nanoparticles (Ag-NPs). The fish were exposed to different concentrations of Ag-NPs for 48 h and 96 h. After exposure, antioxidant enzyme levels were measured, including glutathione-S-transferase (GST), superoxidase dismutase, and catalase (CAT). Other biochemical parameters and histological abnormalities in different tissues (i.e., the liver, gills, and brain) were also examined. The results showed that Ag-NPs agglomerated in freshwater used during the exposure experiments, with particle size remaining <100 nm. Ag-NPs had no lethal effect on fish after 4 days of exposure. Biochemical analysis showed that enzymatic activities in the brain of the fish exposed to 200 𝜇g/L of Ag-NPs were significantly reduced. Varied antioxidant enzyme activity was recorded in the liver and gills. Varied antioxidant enzyme activity was recorded for CAT in the liver and GST in the gills of the fish. However, the recovery rate of fish exposed to 200 𝜇g/L of Ag-NPs was slower than when lower particle concentrations were used. Other biochemical indices showed no significant difference, except for NH3 and blood urea nitrogen concentrations in fish exposed to 50 𝜇g/L of Ag-NPs. This study provides new evidence about the effects of nanoparticles on aquatic organisms.

A Transfer of Silver Nanoparticles from Pregnant Rat to Offspring

Abstract: Silver nanoparticles (size: 7.9 ± 0.95 nm, dosage: 250 mg/kg) were orally administered to pregnant rats. At 4 days after parturition, four pups were randomly selected (one pup from one dam) and silver level in liver, kidney, lung and brain was determined by ICP-MS and electron microscope. As results, silver nanoparticles highly accumulated in the tissues of the pups. Silver level in the treated group was 132.4 ± 43.9 ng/g in the kidney (12.3 fold compared to control group), 37.3 ± 11.3 ng/g in the liver (7.9 fold), 42.0 ± 8.6 ng/g in the lung (5.9 fold), and 31.1 ± 4.3 ng/g in the brain (5.4 fold). This result suggested that the possible transfer of silver nanoparticles from pregnant dams to the fetus through mainly placenta.

Serum kinetics, distribution and excretion of silver in rabbits following 28 days after a single intravenous injection of silver nanoparticles

Abstract: Serum kinetics, tissue distribution, and excretion of citrate-coated silver nanoparticles (AgNPs) were investigated in rabbits (n = 4) up to 28 days after a single intravenous injection. Following a single injection of AgNPs, the AUC(last) was reported to be 3.65 ± 0.68 μg·day/ml in 5 mg/kg-treated group and 0.90 ± 0.16 μg·day/ml in 0.5 mg/kg-treated group, respectively. The accumulation of silver was observed in all the tested organs including liver, kidney, spleen, lung, brain, testis, and thymus at 1 day, 7 day, and 28 day of measurement. The liver and spleen seemed to be the major targets because of high accumulation of silver. Excretion via feces and urine was also monitored during the entire experimental period. Unexpectedly, much more excretion of silver occurred via feces than through urine after an intravenous injection, which suggests biliary excretion of AgNPs. General toxicity was analyzed and histopathological changes were also evaluated.

Task-based exposure assessment of nanoparticles in the workplace

Abstract: Although task-based sampling is, theoretically, a plausible approach to the assessment of nanoparticle exposure, few studies using this type of sampling have been published. This study characterized and compared task-based nanoparticle exposure profiles for engineered nanoparticle manufacturing workplaces (ENMW) and workplaces that generated welding fumes containing incidental nanoparticles. Two ENMW and two welding workplaces were selected for exposure assessments. Real-time devices were utilized to characterize the concentration profiles and size distributions of airborne nanoparticles. Filter-based sampling was performed to measure time-weighted average (TWA) concentrations, and off-line analysis was performed using an electron microscope. Workplace tasks were recorded by researchers to determine the concentration profiles associated with particular tasks/events. This study demonstrated that exposure profiles differ greatly in terms of concentrations and size distributions according to the task performed. The size distributions recorded during tasks were different from both those recorded during periods with no activity and from the background. The airborne concentration profiles of the nanoparticles varied according to not only the type of workplace but also the concentration metrics. The concentrations measured by surface area and the number concentrations measured by condensation particle counter, particulate matter 1.0, and TWA mass concentrations all showed a similar pattern, whereas the number concentrations measured by scanning mobility particle sizer indicated that the welding fume concentrations at one of the welding workplaces were unexpectedly higher than were those at workplaces that were engineering nanoparticles. This study suggests that a task-based exposure assessment can provide useful information regarding the exposure profiles of nanoparticles and can therefore be used as an exposure assessment tool.

Subacute inhalation toxicity assessment of fly ash from industrial waste incinerators.

Abstract: Fly ash from industrial waste incinerators has been a significant concern because of their constituent toxic heavy metals and organic compounds. The objective of this study was to identify the subacute inhalation toxicity of fly ash from industrial waste incinerators, using whole body inhalation exposure chambers. Male and female groups of Sprague-Dawley rats were exposed to fly ash by inhalation of concentrations of 0, 50, 100, 200 mg/m3, for 6 h/day, 5 days/week for 4 weeks. There was no significant difference in body weight, and relative organ weight to body weight, between the exposure groups and the control group. Hematological examinations revealed a significant increase of monocyte counts in fly ash exposed rats and brown pigment laden macrophage was found in the lungs of rats exposed to high concentration of fly ash. A decrease of blood glucose levels and an increase in glutamate oxaloacetate transaminase activity were observed in fly ash treated rats. There was also a significant increase of lact...