Effect of dimethoate on the immune system of female mice

The functional status of the immune system of female mice exposed to a single oral dose of dimethoate (16 mg/kg) was evaluated by assessing cell mediated and humoral immune responses, in addition to the effect of dimethoate on spleen and body weights after different time intervals. The data showed that dimethoate caused a time-depended decrease in spleen weights in the absence of a change in body weights. The immunologic effect of dimethoate to female mice produced a dose-dependent decrease in the number of the rosette forming cells (total and active erythrocyte rosette). The ability of splenocytes to proliferation in response to mitogens; phytohemagglutinin (PHA) for T cell and lipopolysaccharide (LPS) for B cell were significantly decreased at the different times. As compared to control, a significant decrease in serum total immunoglobulins (Ig) and IgM was found, while IgG was non-significant deceased. Results of this study also revealed that dimethoate caused a significant decrease in the number of plaque forming cell (PFC/10(6) splenocytes) in a time dependent manner.     

Effect of dimethoate on the immune system of female mice

Abstract

The functional status of the immune system of female mice exposed to a single oral dose of dimethoate (16 mg / kg) was evaluated by assessing cell mediated and humoral immune responses, in addition to the effect of dimethoate on spleen and body weights after different time intervals. The data showed that dimethoate caused a time ‐ depended decrease in spleen weights in the absence of a change in body weights. The immunologic effect of dimethoate to female mice produced a dose‐dependent decrease in the number of the rosette forming cells (total and active erythrocyte rosette). The ability of splenocytes to proliferation in response to mitogens; phytohemagglutinin (PHA) for T cell and lipopolysaccharide (LPS) for B cell were significantly decreased at the different times. As compared to control, a significant decrease in serum total immunoglobulins (Ig) and IgM was found, while IgG was non‐significant deceased. Results of this study also revealed that dimethoate caused a significant decrease in the number of plaque forming cell (PFC / 10⁶ splenocytes) in a time dependent manner.     

T cell-derived IL-5 production is a sensitive target of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

The immune system is one of the organs most vulnerable to the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Among the various immunotoxic effects of TCDD, the thymus involution and suppression of IgM antibody production are well known sensitive reactions of the thymocytes and B cells affected by TCDD. Recently, we reported that TCDD greatly inhibits the production of type-2 helper T (Th2) cell-derived cytokines, especially IL-5, by the splenocytes in mice immunized with ovalbumin (OVA). In the present study, we investigated the dose-dependency of these TCDD immunotoxic effects in OVA-immunized mice to identify the most sensitive target. Mice of two age groups, 6 weeks old and 3 weeks old, were dosed with 0.3, 1.0, or 3.0 microg TCDD/kg and immunized with OVA using alum as an adjuvant. Seven days later, the thymus weight, thymocyte population, antigen-specific IgM in the plasma, and IL-5 production by the splenocytes were examined. Among them, IL-5 production was significantly suppressed by all three doses of TCDD and reduced to about 30% by even a small dose of 0.3 microg TCDD/kg in both age groups. The thymus weight was significantly reduced by 1.0 microg or 3.0 microg TCDD/kg, but IgM production was not affected by up to 3.0 microg/kg of TCDD in both age groups. Taken together, the Th2 cell-derived IL-5 production was the most sensitive endpoint detecting TCDD toxicity among those examined. Our results also suggest that effector T cells are targets more vulnerable to TCDD toxicity than thymocytes or antibody-producing B cells in the OVA-immunized mice.     

The combined effect of lead exposure and high or low dietary calcium on health and immunocompetence in the zebra finch (Taeniopygia guttata)

The widespread contamination by lead and the acidification of the environment ask for a better understanding of the effects of the interaction between lead and calcium on various aspects of health, including disease defense, in wildlife. Here, we investigated the effects of chronic exposure to sublethal levels of lead, combined with high or low dietary calcium, on health and several components of immunity in male and female zebra finches (Taeniopygia guttata). Thirty individuals of each sex were randomly assigned to three groups: a control group, a group exposed to lead with an additional calcium source (i.e. grit) and a group exposed to lead without access to an extra calcium source. Lead was administered as lead acetate via the drinking water (20 ppm) for 38 consecutive days. Exposure to lead increased significantly the concentrations of lead in kidney and bone in individuals of the experimental groups. Furthermore, the lack of a calcium supplement significantly enhanced the uptake of lead. Lead did not affect health indices such as hematocrit, spleen mass and body mass, nor the adrenal stress response. Cell-mediated immune responsiveness, assessed by a delayed-type hypersensitivity response to phytohaemagglutinin, was also not affected by lead exposure. On the other hand, lead exposure did significantly suppress the secondary humoral immune response towards sheep red blood cells in females, but only when the additional calcium source was not available. This effect was not found in males, suggesting sexual differences in susceptibility of humoral immunity to lead treatment in zebra finches.     

Photolysis of atrazine in aqueous solution: role of process variables and reactive oxygen species

Photochemical advanced oxidation processes have been considered for the treatment of water and wastewater containing the herbicide atrazine (ATZ), a possible human carcinogen and endocrine disruptor. In this study, we investigated the effects of the photon emission rate and initial concentration on ATZ photolysis at 254 nm, an issue not usually detailed in literature. Moreover, the role of reactive oxygen species (ROS) is discussed. Photon emission rates in the range 0.87?×?10¹⁸–3.6?×?10¹⁸ photons L^?1 s^?1 and [ATZ]₀?=?5 and 20 mg L^?1 were used. The results showed more than 65 % of ATZ removal after 30 min. ATZ photolysis followed apparent first-order kinetics with k values and percent removals decreasing with increasing herbicide initial concentration. A fivefold linear increase in specific degradation rate constants with photon emission rate was observed. Also, regardless the presence of persistent degradation products, toxicity was efficiently removed after 60-min exposure to UV radiation. Experiments confirmed a noticeable contribution of singlet oxygen and radical species to atrazine degradation during photolysis. These results may help understand the behavior of atrazine in different UV-driven photochemical degradation treatment processes.     

Atrazine removal by ozonation processes in surface waters

Abstract

Atrazine (6‐chloro‐N‐ethyl‐N'‐isopropyl‐1,3,5‐triazinedyl‐2,4‐diamine) was treated with ozone alone and in combination with hydrogen peroxide or UV radiation in three surface waters. Experiments were carried out in two bubble reactors operated continously. Variables investigated were the ozone partial pressure, temperature, pH, mass flow ratio of oxidants fed: hydrogen peroxide and ozone and the type of oxidation including UV radiation alone. Residence time for the aqueous phase was kept at 10 min. Concentrations of some intermediates, including deethylatrazine, deisopropylatrazine and deethyldeisopropylatrazine, were also followed. The nature of water, specifically the alkalinity and pH were found to be important variables that affected atrazine (ATZ) removal. Surface waters with low alkalinity and high pH allowed the highest removal of ATZ to be reached. There was an optimum hydrogen peroxide to ozone mass flow ratio that resulted in the highest ATZ removal in each surface water treated. This optimum was above the theoretical stoichiometry of the process. Therefore, to reach the maximum removal of ATZ in a O₃/H₂O₂ process, more hydrogen peroxide was needed in the surface waters treated than in ultrapure water under similar experimental conditions. In some cases, UV radiation alone resulted in the removal of ATZ higher than ozonation alone. This was likely due to the alkalinity of the surface water. Ozonation and UV radiation processes yield different amounts of hydrogen peroxide. Combined ozonations (O₃/H₂O₂ and O₃/UV) lead to ATZ removals higher than single ozonation or UV radiation but the formation of intermediates was higher.     

Atrazine removal by ozonation processes in surface waters

Atrazine (6-chloro-N-ethyl-N'-isopropyl-1,3,5-triazinedyl-2,4-diamine) was treated with ozone alone and in combination with hydrogen peroxide or UV radiation in three surface waters. Experiments were carried out in two bubble reactors operated continuously. Variables investigated were the ozone partial pressure, temperature, pH, mass flow ratio of oxidants fed: hydrogen peroxide and ozone and the type of oxidation including UV radiation alone. Residence time for the aqueous phase was kept at 10 min. Concentrations of some intermediates, including deethylatrazine, deisopropylatrazine and deethyldeisopropylatrazine, were also followed. The nature of water, specifically the alkalinity and pH were found to be important variables that affected atrazine (ATZ) removal. Surface waters with low alkalinity and high pH allowed the highest removal of ATZ to be reached. There was an optimum hydrogen peroxide to ozone mass flow ratio that resulted in the highest ATZ removal in each surface water treated. This optimum was above the theoretical stoichiometry of the process. Therefore, to reach the maximum removal of ATZ in a O3/H2O2 process, more hydrogen peroxide was needed in the surface waters treated than in ultrapure water under similar experimental conditions. In some cases, UV radiation alone resulted in the removal of ATZ higher than ozonation alone. This was likely due to the alkalinity of the surface water. Ozonation and UV radiation processes yield different amounts of hydrogen peroxide. Combined ozonations (O3/H2O2 and O3/UV) lead to ATZ removals higher than single ozonation or UV radiation but the formation of intermediates was higher.     

Modeling the reaction kinetics of Fenton's process on the removal of atrazine

The degradation of pesticide, atrazine (ATZ), 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine, by Fenton's reagent (FR) was investigated as a function of reagents' concentrations and ratios in a batch reactor. The degradation of ATZ was effectively achieved by hydroxyl radicals, which were generated in the FR process. The decay rates of ATZ and the oxidation capacities of FR were found to depend on the concentrations of hydrogen peroxide and ferrous ion. The removal kinetics of ATZ are initiated by a rapid decay and then followed by a much slower one. After an extended reaction time (5-10 min), the reactions ceased because the Fe(II) and H(2)O(2) were consumed and would be deactivated in the process. A mathematical model was successfully developed to describe the two-stage reaction kinetics by using two simple but critical parameters: the initial ATZ decay rate and the final oxidation capacity of Fenton's process. In general, higher [Fe(II)] or H(2)O(2) concentrations result in faster initial decay rate and higher oxidation capacity. However, the oxidation capacity is more sensitive to the initial [Fe(II)] due to the presence of side reactions as discussed in the paper.     

Immunostimulating effects of Ginkgo biloba extract against toxicity induced by organophosphate pesticide,diazinon in rainbow trout,Oncorhynchus mykiss: innate immunity components and immune-related genes

The immunostimulating and therapeutic properties of Ginkgo biloba (GB) have always been the focus of traditional medicine over thousands of years. During last decade, special attentions were paid to use of GB in aquaculture to enhance fish health and survival. In the present study, we investigated for the first time the immunogenic effects of dietary GB against oxidative and toxicity induced by organophosphate pesticide, diazinon. In non-diazinon-exposed fish, the plasma total immunoglobulin, lysozyme activity, and peroxidase activity significantly elevated after 60-day experiment in fish supplemented with 1 and 2 g GB/kg diet (p < 0.05). The respiratory burst activity and complement activity significantly increased only in groups supplemented with 0.5 g GB/kg diet (p < 0.05). Furthermore, the peroxidase activity, total immunoglobulin, and lysozyme activity significantly declined in groups supplemented with 4 g GB/kg diet during feeding trial (p < 0.05). There were no significant differences in expression of interleukin 1 beta (IL-1β) and transforming growth factor beta 1 (TGF-β1) genes in kidney between control group (non-GB-supplemented fish) and GB-supplemented fish (p > 0.05). In diazinon-exposed fish, all immunity components significantly decreased during exposure in control and those fed 0.5 and 4 g GB/kg diet (p < 0.05). In fish fed 1 and 2 g GB/kg diet, no alternations were found in immunity components during exposure period (p > 0.05). In addition, diazinon induced the expression of IL-1β and TGF-β1 genes in control and fish fed 0.5 and 4 g GB/kg diet (p < 0.05). No significant changes were observed in expression of IL-1β and TGF-β1 genes in fish supplemented with 1 and 2 g GB/kg (p > 0.05). In conclusion, the results of the present study suggest an immunogenic role for dietary GB at optimum dietary levels (1–2 g GB/kg diet) against toxicity induced by diazinon. Nevertheless, GB at high dietary levels (4 g GB/kg diet) showed immunosuppressive effects, which makes it necessary to optimize its levels in diet.

     

Influence of Cd on atrazine degradation and the formation of three primary metabolites in water under the combined pollution

Environmental Science and Pollution Research - To understand the influence of Cd on atrazine (ATZ) degradation in aqueous solution, the degradation of different initial levels of ATZ (0.1, 0.5,...     

Enhancement of ozone oxidation and its associated processes in the presence of surfactant: degradation of atrazine

In this study, the degradation of atrazine (ATZ) by ozone (O3) oxidation and its associated processes (i.e. UV, UV/O3) in the presence and absence of surfactant was investigated and compared. A non-ionic surfactant, Brij 35, was selected. It was found that the presence of a low concentration of surfactant could improve the removal of ATZ by increasing the dissolution of ozone and the indirect generation of hydroxyl radicals. The saturated ozone level and the reaction rate constants were increased with increasing the concentration of surfactant and then decreased at higher surfactant doses at pH level of 2.5. A similar trend was observed at pH level of 7.0 in the presence of bicarbonate ion, because it is capable of deactivating the hydroxyl radicals generating at higher pH level. However, when the radical reactions become dominant in the ozonation (at pH 7.0 without bicarbonate), the saturated ozone level was higher than that with bicarbonate and the kinetic rate constants were increased first and levelled off with increasing of the dose of surfactant. Through the examining of a proposed unit performance index, the low concentration of surfactant is surely beneficial to the ozonation process. Besides, the direct photolysis and photo-assisted ozonation were compared to the ozonation. A significant enhancement on the decay rate of ATZ was resulted exclusively by adding the surfactant. An enhancement index for quantifying the improvement of the various processes was developed.     

Degradation of atrazine by modified stepwise-Fenton's processes

The removal of atrazine (ATZ) by stepwise Fenton's processes (stepwise-FP) was studied and the system models were developed through the examination of reaction kinetics. The study compared the performance of the removal of ATZ by conventional FP with stepwise-FP, where the total dose of H(2)O(2) was split and inputted into the system at different times and/or quantities. The performance of stepwise-FP was found to be better than that of conventional FP. This was probably due to the minimization of the peak concentration of H(2)O(2) in the solution, which reduced the probability that valuable H(2)O(2) and hydroxyl radicals would be consumed in forming weaker radicals. The reaction kinetics of the decay of ATZ in stepwise-FP was found to be a two-stage process; and in each stage, fast decay followed by stagnant decay was observed. Two characterized constants (the initial decay rate and the oxidative capacity) were introduced and were found to be useful in quantifying the stepwise-FP. The models for predicting stepwise-FP with respect to different dosing times and/or asymmetrical doses were developed, and were found to be very useful for evaluating the system performance and/or for process design.     

Immunological alterations in juvenile Pacific herring, Clupea pallasi, exposed to aqueous hydrocarbons derived from crude oil

The effects of acute and subchronic aqueous hydrocarbon exposures in the ppb range (0.2-127microg/L total PAH) on the immune system in Pacific herring (Clupea pallasi) were examined through specific immunocompetency assays and a host resistance model using Listonella anguillarum. Short-term hydrocarbon exposure at the highest concentration significantly enhanced respiratory burst activity (RBA) in macrophages and decreased plasma lysozyme concentrations, however, subchronic exposure (4-57d) reduced RBA. Fish in the high exposure group were also less susceptible to the pathogen L. anguillarum following acute hydrocarbon exposure; however, this group was the most susceptible following subchronic exposures. These results are explained by a measured transient physiological stress response and long-term effects on ionoregulation. This study illustrates that hydrocarbon-elicited effects are dynamic and that toxic outcomes with respect to the teleost immune system depend on chemical concentrations and composition, exposure durations and the specific pathogen challenge.     

Chronic exposure to contaminated drinking water stimulates PPAR expression in mice livers

Mice were fed with source water (SW) and tap water (TW) for 90 d to evaluate hepatotoxicity induced by the drinking water. Histopathologic observation showed no obvious damage to hepatic tissue in the SW and TW groups. However, microarray analysis indicated that the SW and TW exposures affected many metabolic pathways, among which PPAR (peroxisome proliferator-activated receptors) signaling was most susceptible. Immunohistochemical staining demonstrated that both PPAR-α and PPAR-γ were significantly increased in the exposure groups compared to control. Enzyme-linked immunosorbent assay revealed that PPAR-α expression level was increased from 23.37±0.53 ng g(-1) liver weight in control group to 26.60±1.43 ng g(-1) liver weight in SW group and 27.68±1.10 ng g(-1) liver weight in TW group (p<0.05). For PPAR-γ, the expression level was also significantly enhanced from 0.83±0.07 ng g(-1) liver weight in control group to 1.11±0.20 ng g(-1) liver weight in SW group and 1.16±0.07 ng g(-1) liver weight in TW group (p<0.05). The SW and DW posed no obvious hepatotoxicity on mice and PPAR-α/-γ could be used as a novel biomarker to assess public health risk induced by slightly contaminated drinking water.     

Effect of inducers of P-450 cytochrome isoenzymes on TCDD immunosuppressive activity

Drugs inducing different forms of P-450 cytochrome isoenzymes and binding the Ah receptor or not were investigated for their ability to modify 2,3,7,8, tetrachlorodibenzo-p-dioxin (TCDD) immunotoxicity in mice. 3-Methyl-cholanthrene (3MC) and β-naphthoflavone (BNF) administered to TCDD-treated mice caused additive inhibition of humoral antibody production and of responsiveness to concanavallin A (ConA) but not to phytohemagglutinin (PHA) and lipopolisaccharide (LPS) while phenobarbital (PB) never modified TCDD immunosuppression. Natural killer (NK) cell activity was not reduced by single drug treatment or by combined treatments. Hepatic aryl hydrocarbon hydroxylase (AHH) induction by TCDD was not significantly modified by PB, 3MC or BNF.     

Selective effects of fenitrothion on murine splenic T-lymphocyte populations and cytokine/granzyme production

The aim of this study was to investigate in vitro effects of fenitrothion (FNT) on mouse splenic lymphocytes. Here, naïve mice had their spleens harvested and splenocytes isolated. After exposure to FNT for 48 hr: splenocyte viability was measured using a tetrazolium dye assay; cell phenotypes, i.e., B-cells (CD19⁺), T-cells (CD3⁺), and T-cell subsets (CD4⁺ and CD8⁺), were quantified by flow cytometry; and, production of cytokines/granzyme-B was assessed via enzyme-linked immunosorbent assay. The ability for FNT to induce oxidative stress in the cells was evaluated by measuring hydroxyl radical (·OH) and malondialdehyde (MDA) production and changes in glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activity. The results showed that FNT significantly inhibited splenocyte proliferation, and decreased production of interleukin (IL)-2, interferon gamma, IL-4, and granzyme B, but had no impact on IL-6 production. FNT also selectively decreased splenic T-cell levels but did not induce changes in CD19⁺ B-cells. Further, within the T-cell populations, percentages of CD3⁺, CD4⁺, and CD8⁺ T-cells (particularly CD8⁺ T-cells) were reduced. Lastly, FNT selectively increased MDA and ·OH production and inhibited SOD and GSH-Px activities in the splenic lymphocytes. These findings suggest that, due to oxidative damage, FNT selectively inhibits splenic T-lymphocyte survival and cytokine/granzyme production in vitro.     

Oxidative damage induced in hearts, kidneys and spleens of mice by landfill leachate

The effects of the Xingou landfill leachate on levels of thiobarbituric acid reactive substances (TBARS) and the activities of Cu, Zn-superoxide dismutase (Cu, Zn-SOD), Se-dependent glutathione peroxidase (Se-dependent GPx) and catalase (CAT) were investigated in hearts, kidneys and spleens of Kunming albino mice of both sexes. Exposure to leachate caused significant increases of TBARS levels in the organs tested from mice of both sexes. For hearts, Cu, Zn-SOD, Se-dependent GPx and CAT activities were significantly increased at high concentrations for male mice, but the activities of these antioxidant enzymes were significantly increased at low concentration and decreased at high concentrations for female mice. For kidneys, Cu, Zn-SOD and Se-dependent GPx activities were significantly increased at high concentrations for male mice, but the activities were significantly increased at low concentrations and the ratio of increase was reduced with the increasing of concentration for female mice; CAT activities remained unchanged for male mice and were significantly increased at all concentrations tested for female mice. For spleens, Cu, Zn-SOD and Se-dependent GPx activities were significantly increased at high concentrations for male mice, but the activities were significantly increased at low concentrations and decreased at high concentrations for female mice; CAT activities remained unchanged for male mice and were significantly increased at high concentrations for female mice. The results suggest that leachate exposure can cause oxidative damage on hearts, kidneys and spleens of mice, and there were sex difference and organ difference in the response of antioxidant status.     

Effects of individual ozone exposure on lung function in the elderly: a cross-sectional study in China

The aim of this study was to assess the acute health effects of individual ozone (O₃) exposure on the respiratory system in the elderly. A total of 40 non-smoking elderly volunteers completed personal 24 h of measurement for O₃ and fine particulate matter (PM_2.5). To assess health effects, we measured the pulmonary function and five inflammatory biomarkers in exhaled breath condensate (EBC), including interleukin-2 (IL-2), interferon-γ (IFN-γ), prostaglandin E₂ (PGE₂), and tumor necrosis factor α/β (TNFα/β). We used the generalized additive model to analyze the association between O₃ and these health effects, after adjusting PM_2.5, BMI, and sex as confounders. As a result, we found a negative correlation between O₃ and forced vital capacity (FVC) or forced expiratory volume-one second (FEV1). With the increasing of O₃ by 10 μg/m³, FVC and FEV1 decreased by 0.13 L (95% CI 0.01, 0.26) and 0.11 L (95% CI 0.02, 0.20), respectively. We found no statistical significance between O₃ and biomarkers in EBC. The results suggested that individual 24-h O₃ exposure was associated with decreased pulmonary function in the elderly.

     

Bendiocarbamate induced structural alterations in rabbit thymus after experimental peroral administration

In this study histological structure of rabbit thymus after bendiocarbamate (2,3–isopropyledene–dioxyphenyl methylcarbamate) administration was studied. Bendiocarbamate was perorally administered for 90 days. At Day 3, 10, 20, 30, 60, 90 morphometric analysis was realized. Quantitative evaluation showed that in the control group thymus cortex forms 57.94 ± 7.10% and medulla 35.94± 7.38%. In almost all experimental groups significantly higher relative volume of cortex and lower relative volume of medulla was detected. Detail morphometric analysis found that the number of thymocytes per constant area and the diameter of tymocytes was decresed after bendiocarbamate administration. The number and diameter of reticular cells was not affected. Results of this study suggest negative effect of bendiocarbamate on the formation of thymus structures.