We designed and fabricated a novel high throughput brain-on-chip with three dimensional structure with the aim to simulate the in vivo three-dimensional growth environment for brain tissues. The chip consists of a porous filter and 3D brain cell particles, and is loaded into a conventional 96-well plate for use. The filter and the particle molds were fabricated by using computer modeling, 3D printing of positive mold and agarose-PDMS double reversal mold. The 3D cell particles were made by pouring and solidifying a suspension of mouse embryonic brain cells with sodium alginate into a cell particle mold, and then cutting the resulting hydrogel into pieces. The loaded brain-on-chip was used to determine the neurotoxicity of pesticides. The cell particles were exposed to 0, 10, 30, 50, 100 and 200 µmol/L of chlorpyrifos or imidacloprid, separated conveniently from the medium by removing the porous filter after cultivation. Subsequently, cell proliferation, acetylcholinesterase activity and lactate dehydrogenase release were determined for toxicity evaluation. The embryonic brain cells were able to grow and proliferate normally in the hydrogel particles loaded into the filter in a 96-well plate. Pesticide neurotoxicity test showed that both chlorpyrifos and imidacloprid presented dose-dependent inhibition on cell growth and proliferation. Moreover, the pesticides showed inhibition on acetylcholinesterase activity and increase release of lactate dehydrogenase. However, the effect of imidacloprid was significantly weaker than that of chlorpyrifos. In conclusion, a novel brain-on-chip was developed in this study, which can be used to efficiently assess the drug neurotoxicity, pharmacodynamics, and disease mechanism by combining with a microtiterplate reader.
Animals ; Brain ; Chlorpyrifos/toxicity* ; Culture Media ; Mice ; Oligonucleotide Array Sequence Analysis ; Pesticides/toxicity*

Adsorption ; Adult ; Charcoal ; chemistry ; Chlorpyrifos ; chemistry ; toxicity ; Female ; Hemoperfusion ; Humans ; Insecticides ; chemistry ; toxicity ; Male ; Middle Aged ; Organophosphate Poisoning ; blood ; therapy ; Young Adult

OBJECTIVETo investigate toxicokinetic parameters impacted by hemoperfusion after oral chlorpyrifos exposure, to investigate the adsorption effect of hemoperhusion for chlorpyrifos poisoning.

METHODS12 rabbits were divided into two groups after oral exposure with chlorpyrifos 300 mg/kg body weight. Control group: without hemoperfusion; hemoperfusion group: hemoperfusion starts 0.5 h after chlorpyrifos exposure and lasts for 2h. Blood samples were collected at different times, concentrations of chlorpyrifos were tested by GC, then, toxicokinetic parameterswere calculated and analysis by DAS3.0.

RESULTSIn hemoperfusion group, peak time was (7.19±3.74) h, peak concentrations was (1.37±0.56) mg/L, clearance rate was (13.93±10.27) L/h/kg, apparent volume of distribution was (418.18±147.15) L/kg The difference of these parameter were statistically significant compared with control group (P<0.05).

CONCLUSIONHmoperfusion will decrease the inner exposure and load dose of rabbits with chlorpyrifos poisoning.

Animals ; Chlorpyrifos ; pharmacokinetics ; toxicity ; Hemoperfusion ; Metabolic Clearance Rate ; Rabbits ; Toxicokinetics

OBJECTIVE: To determine the chlorpyrifos in human blood by liquid chromatography-tandem mass spectrometry and to validate its application in poisoning cases. METHODS: The samples were extracted by a simple one-step protein precipitation procedure. Chromatography was performed on a Capcell Pack C18 MGII column (250 mm x 2.0 mm, 5 μm) using an isocratic elution of solvent A (0.1% formic acid-water with 2 mmol/L ammonium acetate) and solvent B (methanol with 2 mmol/L ammonium acetate) at 5:95 V:V). RESULTS: The linear ranged from 5 to 500 ng/mL (r = 0.998 7). The limit of detection (LOD) and the lower limit of quantification (LLOQ) were 2 ng/mL and 4 ng/mL, respectively. For this method, the precision and accuracy of intra-day and inter-day were < 10% and 97.44%-101.10%, respectively. The results in stability test of long-term frozen were satisfied. The matrix effect, recovery and process efficiency were 64.97%-86.81%, 76.70%-85.52%, and 55.57%-66.58%, respectively. CONCLUSION This method can provide a rapid approach to chlorpyrifos extraction and determination in toxicological analysis of forensic and clinical treatment.
Chlorpyrifos/blood* ; Chromatography, High Pressure Liquid/methods* ; Chromatography, Liquid/methods* ; Humans ; Limit of Detection ; Poisoning ; Reproducibility of Results ; Tandem Mass Spectrometry/methods*

Chemotherapeutic treatment is still the foundation of tick control programs. This study investigated the acaricidal efficacy of cypermethrin alone and in combination with chlorpyrifos against Haemaphysalis (H.) longicornis. Unfed larval ticks were exposed to 0.1, 1.0, and 10 mg/mL cypermethrin for 60 min, after which the acaricidal efficacy was examined based on tick mortality. All compounds showed similar suppression curves, with the best control being achieved by cypermethrin and chlorpyrifos (1 : 1 ratio) at 10 mg/mL. Effective cypermethrin concentrations for tick control were two to seven times higher than the recommended doses, indicating resistance by H. longicornis.
Chlorpyrifos* ; Ixodidae* ; Mortality ; Tick Control ; Ticks

Aged ; Chlorpyrifos ; Dermatitis, Occupational ; etiology ; Female ; Humans ; Insecticides ; poisoning ; Middle Aged ; Organophosphate Poisoning ; complications

Acute Disease ; Adult ; Chlorpyrifos ; Humans ; Insecticides ; poisoning ; Male ; Organophosphate Poisoning ; complications ; Rhabdomyolysis ; chemically induced

OBJECTIVETo establish the method of detecting the concentrations of chlorpyrifos in air of workplace with high performance liquid chromatographic (HPLC).

METHODSAccording to standards of methods for determining the chemical substances in workplace air, chlorpyrifos in the air was collected by silicone tube, then dissolved by acetonitrile and determined by high performance liquid chromatography with UV-detector.

RESULTSThere was a linear relationship within the range of 0 ∼ 10.0 µg/ml, and regression equation was y = 5206.1x - 104.7, correlation coefficient was 0.9999, the detection limit was 0.006 µg/ml. The lowest detected concentration was 0.001 mg/m(3) (sampling volume 4.5 L). The average recoveries was 98.3% ∼ 102.5%. The within-run precision was 1.96% ∼ 4.39%, the between-run precision was 2.76% ∼ 5.87%. The desorption efficiencies were 99.0% ∼ 103.3% and the sampling efficiencies were 94%. The samples in silicone tube could be stored for 15 days at room temperature.

CONCLUSIONThe present method could meet with the requirements of Guide for establishing occupational health standards-Part 4 Determination methods of air chemicals in workplace and be feasible for determination of chlorpyrifos in workplace air.

Air Pollutants, Occupational ; analysis ; Chlorpyrifos ; analysis ; toxicity ; Chromatography, High Pressure Liquid ; methods ; Limit of Detection ; Reproducibility of Results ; Workplace

OBJECTIVETo explore the effects of low-dose chlorpyrifos (CPF) exposure on dopaminergic (DA) neurons in the midbrain substantia nigra and neural behavioral development in neonatal rats.

METHODSPostnatal 11 day old Sprague-Dawley rats were randomly assigned into CPF, menstruum dimethysulfoxide (DMSO) and normal saline (NS) groups. The rats in the CPF group were injected with low-dose CPF (5 mg/kg?d) on postnatal days 11-14. The two control groups were injected with DMSO or NS respectively. The rats were sacrificed on postnatal days 15, 20, 30, and 60. Body weight gain, outward appearance of brain tissue, the coefficient of brain and the water content of brain tissue were measured. Tyrosine hydroxylase (TH) expression in DA neurons in the midbrain substantial nigra was examined by immunohistochemical straining. Immune electron microscopy was used to examine the subcellular structure of DA neurons. Open field test, grip strength test, slope test and Morris water maze test were used to examine the neurobehavioral changes.

RESULTSThe outward appearance of brain tissue was normal in the three groups. There were no significant differences in the absolute value of body weight gain, the coefficient of brain and the water content of brain tissue among the three groups. CPF exposure decreased the level of TH immunoreactivity (P<0.05) in the substantia nigra of CPF group since postnatal day 30 compared with the DMSO and NS groups. The subcellular structures of some DA neurons in the CPF group were impaired. Decreased motor activity and learning and memory impairments were observed in the CPF group compared with those in the DMSO and NS groups (P<0.05) since postnatal day 30.

CONCLUSIONSCPF exposure during the neonatal period can cause long-term motor activity and learning and memory impairments in accompany with DA neurons damage in the midbrain substantia nigra.

Animals ; Animals, Newborn ; Behavior, Animal ; drug effects ; Chlorpyrifos ; toxicity ; Dopaminergic Neurons ; drug effects ; Female ; Insecticides ; toxicity ; Learning ; drug effects ; Male ; Motor Activity ; drug effects ; Rats ; Rats, Sprague-Dawley ; Substantia Nigra ; drug effects

The extensive and intensive use of pesticides in agricultural practices has exposed farmers to various hazards resulting in varying degrees of health outcomes. We conducted a cross-sectional study among paddy farmers in Sabak Bernam district, Malaysia. The objective of this study was to gather baseline information on chlorpyrifos blood level and its relationship with pesticides exposure symptoms. We detected chlorpyrifos in farmers’ blood in 7 percent of the respondents, with mean 7.29 nanogram per millilitre blood (sd 5.84 nanogram per millilitre). The percentage of farmers who experienced at least one pesticide exposure symptoms was 75 percent. However, we found no significant association between chlorpyrifos blood level and its exposure symptoms. The farmers had low scores on safe practice of pesticide use even though they have high marks on knowledge and attitude. We found no significant association between the scores on knowledge, attitude and practice on pesticide use and the chlorpyrifos blood level. The presence of pesticide exposure symptoms proved that most of the farmers were exposed to hazardous effects of pesticides. Specific trainings on safe use and handling of pesticides should be given on regular basis to these farmers to ensure they are protected from hazardous effects of pesticides exposure.
Chlorpyrifos ; Pesticides ; Hazardous Substances