[In vitro study of histocompatibility and clearance of hemoperfusion adsorbents].

Objective: To evaluate the histocompatibility and clearance of chlorpyrifos and its metabolite of activated charcoal and adsorption resin by in vitro study. Methods: Venous blood from volunteers were incubation with activated charcoal or adsorbent resins, cytometry parameters and plasma components were detected for evaluation the histocompatibility of adsorbents. Venous blood from volunteers mixed with chlorpyrifos and its metabolite were incubation with activated charcoal or adsorbent resins, plasma concentration of chlorpyrifos and its metabolite were detected for evaluation the efficacy of adsorbents. Results: Incubation tests show that the absorbents reduce the blood platelet (F=3.671, P<0.05) , serum glucose (F=10.564, P<0.05) , albumin (F=5.239, P<0.05) , uric acid (F=7.175, P<0.05) , creatinine (F=23.673, P<0.05) , T3 (F=11.161, P<0.05) and free T3 (F=10.256, P<0.05) . However, other cytometry parameters and plasma components were not influenced. Both activated charcoal and adsorbent resins could reduce the plasma concentration of chlorpyrifos (F=798.110, P<0.01) and its metabolite (F=1495.212, P<0.05) . Conclusion: In vitro test show that both activated charcoal and adsorbent resins could clear chlorpyrifos and its metabolite, however, could not influence main cytometry parameters and plasma components, the histocompatibility of adsorbents are satisfactory.

An electrochemical immunosensor based on interdigitated array microelectrode for the detection of chlorpyrifos.

An electrochemical immunosensor based on interdigitated array microelectrodes (IDAMs) was developed for sensitive, specific and rapid detection of chlorpyrifos. Anti-chlorpyrifos monoclonal antibodies were orientedly immobilized onto the gold microelectrode surface through protein A. Chlorpyrifos were then captured by the immobilized antibody, resulting in an impedance change in the IDAMs surface. Electrochemical impedance spectroscopy was used in conjunction with the fabricated sensor to detect chlorpyrifos. Under optimum conditions, the impedance value change of chlorpyrifos was proportional to its concentrations in the range of 10(0)-10(5) ng/mL. The detection limit was found to be 0.014 ng/mL for chlorpyrifos. The proposed chlorpyrifos immunosensor could be used as a screening method in pesticide determination for the analysis of environmental, agricultural and pharmaceutical samples due to its rapidity, sensitivity and low cost.

An amperometric immunosensor based on multi-walled carbon nanotubes-thionine-chitosan nanocomposite film for chlorpyrifos detection.

In this work, a novel amperometric immunosensor based on multi-walled carbon nanotubes-thionine-chitosan (MWCNTs-THI-CHIT) nanocomposite film as electrode modified material was developed for the detection of chlorpyrifos residues. The nanocomposite film was dropped onto a glassy carbon electrode (GCE), and then the anti-chlorpyrifos monoclonal antibody was covalently immobilized onto the surface of MWCNTs-THI-CHIT/GCE using the crosslinking agent glutaraldehyde (GA). The modification procedure was characterized by using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under the optimized conditions, a linear relationship between the relative change in peak current of different pulse voltammetry (DPV) and the logarithm of chlorpyrifos solution concentration was obtained in the range from 0.1 to 1.0 × 10(5) ng/mL with a detection limit of 0.046 ng/mL. The proposed chlorpyrifos immunosensor exhibited high reproducibility, stability, and good selectivity and regeneration, making it a potential alternative tool for ultrasensitive detection of chlorpyrifos residues in vegetables and fruits.

Effects of atrazine and chlorpyrifos on the mRNA levels of IL-1 and IFN-γ2b in immune organs of common carp.

Atrazine (ATR) and chlorpyrifos (CPF) are widely used in agriculture has resulted in a series of toxicological and environmental problems. The aim of this study was to investigate the effects of ATR, CPF and their mixture on the mRNA levels of interleukin-1ß (IL-1ß), interleukin receptor I (IL-1RI) and interferon gamma (IFN-γ2b) in both spleen and head kidney of Common carp. In this study, juvenile common carp were exposed to ATR (at concentrations of 4.28, 42.8 and 428 µg/L), CPF (at concentrations of 1.16, 11.6 and 116 µg/L), and their mixture (at concentrations of 1.16, 11.6 and 116 µg/L). The mRNA levels of IL-1ß, IL-1R1 and IFN-γ2b in spleen and head kidney were detected by using RT-PCR. Our results indicated that IL-1ß, IL-1R1 expression significantly increased after exposure in high concentration ATR, CPF and their mixture, but IFN-γ2b mRNA shown different expression trends. Our results suggested that ATR, CPF and their mixture probably induced damages on spleen and head kidney may be association with increasing IL-1ß, IL-1R1 mRNA synthesis. After 20-day recovery test, IL-1ß, IL-1R1 and IFN-γ2b mRNA expression remain at high level in majority of the treated groups, we concluded that the restoration of tissue and immune system damage probably needs longer time.

The cytotoxic effects of the organophosphates chlorpyrifos and diazinon differ from their immunomodulating effects.

Some organophosphate insecticides have immunomodulating capacities, but it is unknown whether different compounds within this class affect the immune system to the same extent. In this in vitro study, human immortalized T-lymphocytes or bronchial epithelial cells were treated with diazinon or chlorpyrifos in the absence or presence of cellular stress factors, thereby mimicking a stimulated immune system. Cytotoxicity was determined and cytokine release or cytokine-promoter studies were performed to study immunomodulatory effects of these chemicals, whereby the same concentrations of chlorpyrifos and diazinon were used. Results showed that chlor- pyrifos was cytotoxic at concentrations >/= 250 muM, whereas diazinon was not toxic at concentrations up to 1 mM. The immunomodulatory effects of these two compounds were similar for most cytokine promoters tested and induction of cellular stress enhanced these effects. The results were compared to data obtained with blood mononuclear cells, which confirmed the results of stably transfected cell lines, but refer to a higher sensitivity of primary cells. In conclusion, these two pesticides act in a different manner on cell viability and on some immune parameters, but cell viability was not linked to immunomodulation. The results also imply that healthy and diseased individuals are differentially affected by these pollutants.

Immunological abnormalities in humans chronically exposed to chlorpyrifos.

Twenty-nine individuals with chronic health complaints following exposure to chlorpyrifos were compared with 3 control groups (i.e., 1 positive and 2 negative) with respect to the following: (1) peripheral lymphocyte phenotypes; (2) autoantibodies (nucleic acids and nucleoproteins, parietal cell, brush border, mitochondria, smooth muscle, thyroid gland, and central nervous system/peripheral nervous system myelin); (3) mitogenesis to phytohemagglutinin and concanavillin. The data revealed an increase in CD26 expression, a decrease in percentage of CD5 phenotype, decreased mitogenesis in response to phytohemagglutinin and concanavillin, and an increased frequency of autoantibodies. The alterations in these peripheral blood markers were unaffected by medications, age, sex, or season. The authors concluded that chronic exposure to chlorpyrifos causes immunological changes.

Properties of polyclonal, monoclonal, and recombinant antibodies recognizing the organophosphorus pesticide chlorpyrifos-ethyl.

A rabbit polyclonal antiserum and two murine monoclonal antibodies recognizing the organophosphorus pesticide chlorpyrifos-ethyl were produced. The two hybridoma cell lines were then used as sources of immunoglobulin genes for the generation of recombinant scFv antibodies in Escherichia coli. The two scFvs showed either similar or improved limits of detection in an ELISA when compared with the monoclonal antibodies. Cross-reactivity studies showed that all of the antibodies were specific toward the chlorinated aromatic ring. Furthermore, scFv gene sequences were linked directly to sequences coding for either a c-Myc tag, a His-tag, or alkaline phosphatase. The fusion products generated were functional, and their properties were determined. The problems associated with producing scFvs and scFv derivatives for detection of pesticide residues from hybridoma are addressed and discussed.

Functional scFv antibody sequences against the organophosphorus pesticide chlorpyrifos.

Two functional single-chain Fv (scFv) antibodies that recognize specifically the widely used organophosphorus pesticide chlorpyrifos-ethyl were derived from two murine hybridoma cell lines. It is shown that the functional scFvs could be isolated without any rounds of selection, with a success rate dependent on the efficiency of amplification of the functional light chain gene family by the specific primers. Besides four new functional immunoglobulin variable gene sequences, the isolation of a new pseudogene is reported.

The use of regenerable, affinity ligand-based surfaces for immunosensor applications.

The regeneration of antibody-binding surfaces is of major importance for re-usable sensor formats such as required for direct 'real-time' biosensing technologies and is often difficult to achieve. Antibodies commonly bind the antigen with high avidity and may themselves be sensitive to regeneration conditions. The interaction of polyclonal anti-chlorpyriphos antibody with an immobilised chlorpyriphos-ovalbumin (chlor-oval) conjugate and the interaction of soluble recombinant CD4 with covalently immobilised anti-CD4 IgG are presented in order to highlight these difficulties. Affinity-capture is suggested as an alternative format as it facilitates surface regeneration, directed immobilisation and the attainment of interaction progress curves that conform to the ideal pseudo-first-order kinetic interaction model. Protein A, protein G and polyclonal anti-mouse Fe-coated surfaces were used to observe the interaction of captured anti-GST monoclonal antibody with glutathione-s-transferase (GST). It was shown that a protein A affinity-capture surface produced ideal interaction progress curves while both protein G and polyclonal anti-mouse Fe resulted in systemic deviations.

Immunologic abnormalities in humans exposed to chlorpyrifos: preliminary observations.

Twelve individuals who were exposed to chlorpyrifos were studied 1-4.5 y following exposure to determine changes in the peripheral immune system. The subjects were found to have a high rate of atopy and antibiotic sensitivities, elevated CD26 cells (p < .01), and a higher rate of autoimmunity, compared with two control groups. Autoantibodies were directed toward smooth muscle, parietal cell, brush border, thyroid gland, myelin, and ANA. Chlorpyrifos exposure was implicated in the immunologic abnormalities reported. The immunologic changes were similar to those reported for other pesticides.