Effects Of Organophosphorus Pesticides Research Articles

Chlorpyrifos with Age-Dependent Effects in Cardiac Tissue of Male Rats.

Age-dependent toxic effects of organophosphorus pesticides (OPs) have not been fully understood. The current study aimed to investigate the cardiotoxic damage of chlorpyrifos (CPF) by evaluating oxidative modifications in young (2-month old), middle-aged (10- month old), and aged (20-month old) rats. Five mg/kg of CPF was administered orally for 45 days to young, middle-aged, and aged male Wistar rats. In the end, animals were anesthetized and the heart of each rat was dissected for biochemical assay. Malondialdehyde (MDA), nitric oxide (NO), glutathione (GSH), total antioxidant capacity (TAC), and superoxide dismutase (SOD) were assessed in the cardiac tissue of rats. The results indicated an increase in the levels of MDA and NO, and also a decline in the levels of GSH and TAC as well as a decrease in the SOD activity in the heart of aged rats compared with young rats. CPF administration deteriorated these changes in the heart of exposed rats compared with the age-matched controls. Additionally, these oxidative modifications were more severe in aged rats versus other age. In conclusion, advancing age may increase oxidative changes in the heart of animals exposed to CPF. It is suggested that aging can affect cardiac toxicity induced by OPs.

Effect of organophosphorus pesticides in juveniles of Litopenaeus vannamei: alteration of glycogen, triglycerides, and proteins.

The presence of pesticides has recently been reported in shrimp farms adjacent to agricultural areas on the east coast of the Gulf of California. This study assessed the possible effect of organophosphorus pesticides in the coastal environment of Sinaloa, México, using the white shrimp Litopenaeus vannamei as a bioindicator since their presence, abundance or behavior indicate some process or state of the system in which they live. Sublethal bioassays were performed on shrimps in intermolt state using commercial brands of organophosphorus pesticides, chlorpyrifos (0.0015 mg l-1), diazinon (0.0120 mg l-1), methamidophos (1.207 mg l-1), azinphos-methyl (0.0101 mg l-1), and methyl parathion (0.0075 mg l-1) were tested. Results showed reductions in glycogen, triglycerides, and total protein concentrations in shrimp muscle, except for the diazinon treatments, in which an increase in triglyceride level was detected. The observed alterations in the three cellular components were probably due to the metabolic compensation mechanism of the shrimp in reaction to the stress produced by organophosphorus pesticides, which act as endocrine disruptors. The establishment of continuous environmental monitoring programs of the coastal zone of Northwestern Mexico is strongly recommended.

Effects of Organophosphorus Pesticides on Cardiorespiratory Parameters among the Farmers.

Indiscriminate use and improper handling of synthetic pesticides in agriculture have resulted in serious problems such as asthma, wheeze and chronic bronchitis among the farmers. Though number of studies have been done on pesticide exposure and its effect on cardiorespiratory parameters in Northern India, only few studies were done in Southern India, thus this study was chosen. To find the cardiorespiratory changes in farm workers exposed to organophosphorus pesticides. Peak Expiratory Flow Rate (PEFR), blood pressure, pulse rate were measured among 35 farm workers of Palayam and Naduveerpattu village of Cuddalore district and 35 age, sex, BMI matched controls were taken from urban area and the same parameters were measured in both groups from 10 am-12 am in the morning. History of use of personal protective equipments like face mask, eye mask, special clothes, shoes, hat, history of respiratory symptoms and hygienic work practices was also obtained from the farmers. Chi-square test was used to analyse the qualitative data. All values were expressed as Mean±SD. Students unpaired t-test was used to compare PEFR between two groups and to compare the duration of exposure and PEFR using GRAPH PAD PRISM. The p<0.05 was considered to be statistically significant. There was a significant decrease in PEFR among the farmers (p<0.001) compared to the controls. On comparing the duration of exposure of pesticide and the PEFR values by unpaired Students t-test, there was a significant difference with p-value of 0.03. Blood Pressure did not show any significant difference between the two groups. But the pulse rate was significantly decreased among the farmers (p<0.001) which could be due to their regular physical activity. About 71% of the farmers used personal protective equipments. Thus, chronic exposure to organophosphorus pesticides has an impact on PEFR among the farmers.

Modulation of immune response by organophosphorus pesticides: fishes as a potential model in immunotoxicology.

Immune response is modulated by different substances that are present in the environment. Nevertheless, some of these may cause an immunotoxic effect. In this paper, the effect of organophosphorus pesticides (frequent substances spilled in aquatic ecosystems) on the immune system of fishes and in immunotoxicology is reviewed. Furthermore, some cellular and molecular mechanisms that might be involved in immunoregulation mechanisms of organophosphorus pesticides are discussed.

Temperature changes among organophosphate poisoned patients, Tehran- Iran

BackgroundAcute poisoning with organophosphorus compounds (OPs) is a major global clinical problem in the developing countries. There have been many animal studies and few human surveys on the effects of organophosphorus pesticide (OP) poisoning on thermoregulation. The aim of this prospective study was to document the pattern of tympanic temperature changes among OP poisoned patients throughout the length of their hospital stay.Methods60 patients with diagnose of organophosphate poisoning were included in this study. Questioner was filled out by trained nurses including demographic, clinical and paraclinical data. Tympanic temperature and Pulse rate data of the cases were collected on five- occasions after admission.ResultsThere were 41 (68.3%) male and 19 (31.7%) female, with a mean age of 34.4 ±19.4 years (range 13–89 years). Forty five patients had intentional poisoning for suicidal attempt. At the time of entry, the mean tympanic temperature, pulse rate, respiratory rate and blood pressure (systolic and diastolic) of the OP poisoned patients were respectively 37.1+/−0.6°C (36.0- 39.5), 91+/−18 (55–145), 18+/−5.6 (8–44), 116+/−20 mm Hg (70–170) and 75+/−11.6 mm Hg (40–110). 41.7% of the cases had serum butyryl cholinesterase activities (BChE) ≥ 50% normal (≥1600 mU/ml). Our patients had normal temperature at the time entry (mean = 37.1). Tympanic temperature decreasing below 36°C was not detected among the patients during the study period. A rise in mean tympanic temperature was found after atropine administration.ConclusionOur study showed hypothermia was not considerable factor among organophosphate poisoned patients, although more studies with similar situations in tropical countries are needed.

Hypothermia and Fever After Organophosphorus Poisoning in Humans—A Prospective Case Series

There have been many animal studies on the effects of organophosphorus pesticide (OP) poisoning on thermoregulation with inconsistent results. There have been no prospective human studies. Our aim was to document the changes in body temperature with OP poisoning. A prospective study was conducted in a rural hospital in Polonnaruwa, Sri Lanka. We collected data on sequential patients with OP poisoning and analyzed 12 patients selected from 53 presentations who had overt signs and symptoms of OP poisoning and who had not received atropine prior to arrival. All patients subsequently received specific management with atropine and/or pralidoxime and general supportive care. Tympanic temperature, ambient temperature, heart rate, and clinical examination and interventions were recorded prospectively throughout their hospitalization. Initial hypothermia as low as 32°C was observed in untreated patients. Tympanic temperature increased over time from an early hypothermia (<35°C in 6/12 patients) to later fever (7/12 patients >38°C at some later point). While some of the late high temperatures occurred in the setting of marked tachycardia, it was also apparent that in some cases fever was not accompanied by tachycardia, making excessive atropine or severe infection an unlikely explanation for all the fevers. In humans, OP poisoning causes an initial hypothermia, and this is followed by a period of normal to high body temperature. Atropine and respiratory complications may contribute to fever but do not account for all cases.

Morbidity in newborns exposed to organophosphorus pesticides

Insecticides are toxins by which we destroy harmful insects. The most frequent insecticides which are used today are organophosphorus pesticides. This group of compounds make substances whose activity mechanism is based on the inhibition of acetylcholinesterase in nerve synapsis, thus producing holynergic syndrome, resulting from the accumulation of acetylcholine which developed due to the absence of decomposition under the influence of cholinesterase. In the clinical picture of acute toxication by cholinesterase inhibitors there is a clear difference between muscarinic and nicotine effects. The basic aim of the study was to establish the effects of organophosphorus pesticides present in blood and breast milk of mothers on newborns morbidity. The study group consisted of 18 newborns whose mothers had isolated organophosphorus pesticides in their blood and breast-milk on the third day after delivery, and the control group consisted of 84 newborns whose mothers did not have isolated organophosphorus pesticides in their blood and breastmilk. Morbidity is three times greater, often in combination with some disorders of the central nervous system, and the relative risk for its appearance is eight time greater in newborns exposed to organophosphorus pesticides. Disorders that appear in newborns exposed to pesticides are mutagenic, cancerogenic and neurotoxic and some agenses could disturb the immune system which is reflected in morbidity increase, primarly of the central nervous system. The presence of organophosphorus pesticides in blood and breast milk has negative effects on newborns. In addition to acetylcholinesterase inhibition, organophosphorus pesticides react by means of other mechanisms as well.

Acute and repeated effects of three organophosphorus pesticides on the acquisition and retention of an instrumental learning task in rats

The effects of organophosphorus pesticides on higher functions of the central nervous system are not well understood yet. As a first approach, the acute and repeated effects of three organophosphorus pesticides on learning and memory capabilities of behaving adult rats were studied here. Prior to training, animals received acute or repeated (5-day, 15-day, and 30-day) doses of diazinon, malathion, or fenitrothion. Animals were trained with an operant conditioning test, using a fixed-interval (FI 2 min) paradigm. Fifteen days later, animals were tested for retention of the learned task. Specific modifications in some selected behavioral displays were also quantified across the training process. Although their motor behaviors were not affected, treated animals required longer times for the acquisition of the fixed-interval test than did controls. As opposed to controls, not all (45.8% for diazinon, 66.6% for malathion, and 62.5% for fenitrothion) treated animals reached criterion during the retention test. Specific behaviors, such as grooming, rearing, exploratory whisking, and freezing, were modified at different levels by some (or all) of the three organophosphorus pesticides. According to these results, the three organophosphorus pesticides used here affected the acquisition and, mainly, the retention of instrumental conditioning, using a fixed-interval paradigm. The presentation of some specific behavioral displays was also modified in treated animals.

Effects of organophosphorus pesticides and their ozonation byproducts on gap junctional intercellular communication in rat liver cell line

The effects of organophosphorus pesticides (OPs), oxons and their ozonation byproducts on gap junctional intercellular communication (GJIC) on cultured BRL cell line were investigated using scrape loading and dye transfer (SL/DT) technique. The neutral red uptake assay was used to identify the non-cytotoxic levels of diazinon, parathion and methyl-parathion applied to GJIC assay. The concentration-dependent inhibition of GJIC was observed over a range of 50–350 mg/l diazinon, parathion and methyl-parathion after 90 min incubation compared with the vehicle control. However, oxons and ozonation byproducts of OPs had no inhibition effect on GJIC at any of the concentrations tested. The inhibition of GJIC by OPs was reversible after removal of the tested pesticides followed by incubation with fresh medium. The present study suggested that the ozonation treatment could be used for the detoxification of drinking water and food crops contaminated with diazinon, parathion and methyl-parathion without formation of GJIC toxicity.

Affinity Methods to Immobilize Acetylcholinesterases for Manufacturing Biosensors

Two new affinity methods to immobilize acetylcholinesterase (AChE) onto screen‐printed electrodes (SPE) are described and compared for the fabrication of SPE: one based on metal chelate affinity (MCA) and one based on the Concanavalin A (Con A), a sugar residue binding lectine. The manufacturing and the optimization procedure for each type of biosensor are discussed with respect to no‐specific binding, functionalization of the SPE surface and the amount of enzyme used. A linear response range to acetylthiocholine substrate between 10 and 100 µmol L−1 was obtained for Con A sensors and between 1 and 60 µmol L−1 with the MCA sensors. The possibilities to reuse the sensors fabricated using both affinity immobilization chemistries were also discussed. The optimized sensors were used to study the inhibitory effects of organophosphorus pesticides on immobilized AChE activity. A detection limit of 5 × 10−7 mol L−1 chlorpyrifos methyl‐oxon (ee AChE sensor) and 2 × 10−9 mol L−1 paraoxon (dm AChE sensor) was achieved for the sensors with the enzyme attached via Con A and NTA–Ni, respectively.

Population Responses of Peromyscus Resident in Iowa Cornfields Treated with the Organophosphorus Pesticide COUNTER

We examined the effects of a field application of 1.41 kg/ha active ingredient COUNTER® insecticide on resident small mammal populations in a corn agroecosystem in Iowa. The majority of individuals captured were Peromyscus maniculatus and Peromyscus leucopus; preliminary results showed no differential effects by species and further analyses were done at the generic level. The study design was a treatment-reference and before-after application comparison. Demographic parameters examined were: minimum number known alive, total number of captures as an index of activity, captures by habitat type, number of first captures (recruitment) and last captures (mortality plus emigration), sex ratio, age class structure, and several measures of reproductive activity. Brain ChE levels were also examined for treatment and reference animals. COUNTER® residues were detected only in treatment site mice. There were no significant differences in most demographic parameters. There was a significant interaction between reproductive activity and time (three factor loglinear analysis); however the effect was consistent on the treatment and reference sites. There was a significant increase in activity measured as number of captures on the reference site relative to the treatment site post-application as well as a lower than expected number of captures in the cornfield habitat on the treatment site post-application; this did not appear to be related to mortality on the treatment site. The only possible treatment effect appeared to be some depression of activity, especially in the corn field; this is consistent with other published research on the effect of organophosphorus pesticides on small mammals in agroecosystems.

Proposed protocols for the determination of potential ocular effects of organophosphorus pesticides.

The US Environmental Protection Agency now requires ocular toxicity testing to support the registration of organophosphorus pesticides. As a first step toward guideline development for the conduct of these studies, preliminary protocols for ocular toxicity testing in the non-rodent and rodent are being proposed by the Office of Pesticide Programs. Proposed protocol parameters include determination of animal health status, measurement of plasma, erythrocyte and retinal cholinesterase activities, ocular assessment by routine ophthalmological examination, slit lamp biomicroscopy, fundic observations, tonometry, electroretinography and determination of objective refractivity, pupillary response and tracking. Gross and detailed histopathological examinations of ocular system components would also be conducted. Associated questions and concerns with regard to ocular toxicity testing are presented. The Agency plans to hold a workshop in the near future to discuss issues related to protocol refinement and guideline development.

Mutagenicity studies on fenitrothion in Drosophila.

To extend the data on the possible genotoxic effects of organophosphorus pesticides, the insecticide fenitrothion was tested for the induction of gene and chromosome mutations in male germ cells of Drosophila melanogaster. Sex-linked recessive lethals, total and partial sex-chromosome losses and non-disjunction were studied following different exposure methods: adult feeding, injection and larval feeding. In the tests assaying for recessive lethals, we used a MRA strain resistant to malathion. Our results indicate that fenitrothion, at concentrations ranging from 50 to 150 p.p.m., is unable to induce any kind of genetic damage in D. melanogaster, at least under the conditions of testing.

Pesticide interactions: Effects of organophosphorus pesticides on the metabolism, toxicity, and persistence of selected pyrethroid insecticides

The organophosphorus pesticides profenofos, sulprofos, O-ethyl O-(4-nitrophenyl) phenylphosphonothioate (EPN), and S,S,S,-tributyl phosphorotrithioate (DEF) administered intraperitoneally to mice at 0.5 to 5 mg/kg strongly inhibit the liver microsomal esterase(s) hydrolyzing trans-permethrin. Profenofos, EPN, and DEF at 25 mg/kg increase the intraperitoneal toxicity of fenvalerate > 25-fold and of malathion > 100-fold. Topically applied profenofos, sulprofos, and DEF significantly synergize the toxicity of cis-cypermethrin to cabbage looper larvae and house fly adults but these phosphorus compounds are much less effective in synergizing the toxicity of trans-permethrin. The magnitude of synergism appears to depend on the species, organophosphorus compound, and pyrethroid involved. Profenofos, sulprofos, and EPN do not significantly alter the persistence of trans-permethrin on bean foliage.

The effects of organo-phosphorus pesticides on the respiration of Azotobacter vinelandii

The effects often organo-phosphorus pesticides at 2 and 100 parts/10 6 upon O 2-uptake of Azotobacter vinelandii with glucose as substrate was studied by means of polarography. When washed suspensions of the bacterium were exposed to the pesticides for 2 h before measurement of oxygen uptake. respiration rate was greatly reduced in the case of Naled, Terracur-P, Coumaphos. DDVP, Malathion. Nemacur-P, Chlorpyrifos, DOWCO 217 and DOWCO 214 at 100 parts/10 6 concn. At 2 parts/10 6, respiration was inhibited with Naled, Coumaphos, DDVP, Chlorpyrifos and to a lesser extent with DOWCO 217 and Nemacur-P. No inhibition was found with Terracur-P, or DOWCO 214 at 2 parts/10 6 concn. Malathion stimulated respiration at 2 parts/10 6 concn whereas Diazinon stimulated respiration at both concentrations. Endogenous respiration was stimulated by Naled at 2 parts/10 6 and by Nemacur-P and DDVP at both the concentrations. The effect on respiration was less when the bacterium was grown in the presence of 100 parts/10 6 DDVP or Naled, but in the case of Terracur-P there was still a marked inhibition.