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PubMed1963

THE AREA DISTRIBUTION OF AN INSECTICIDE (FENTHION) SPRAYED INSIDE THE HUTS OF AN AFRICAN VILLAGE.

In the course of a village-scale trial of fenthion, carried out in a village near Lagos, Nigeria, 40% fenthion water-dispersible powder was used at a 3.75% concentration. This was applied by Galeazzi "OM" sprayers with constant-pressure assemblies. The target concentration was 1.5 g/m(2). Filter-papers were placed on walls, ceilings and roof beams to determine the actual average rate of application, and glass plates were placed on the floors to determine the rate of "bounce-off" from the walls or of "drop-out" from the ceilings. The results of chemical tests show that the rate actually applied came closest to the target concentration on the walls, followed, in that order, by ceilings and roof beams. There were heavy deposits on the floors up to 30 cm away from the walls. The authors analyse the causes for the variations encountered.

Fenthion↗

PubMed1963

A VILLAGE-SCALE TRIAL OF FENTHION AS A RESIDUAL SPRAY IN NIGERIA.

In the course of an insecticide-testing programme, fenthion was applied in mud-walled huts at an intended concentration of 1.5 g/m(2) in a village near Lagos, Nigeria. This paper describes the entomological results obtained. Bio-assays on Anopheles gambiae showed an effective kill (i.e., over 70%) for 7 weeks on mud surfaces, 11 weeks on wood surfaces and 16 weeks on raffia-palm mid-ribs. No mosquitos were found in pyrethrum spray catches in the treated village for 7 weeks after the application of fenthion, although low numbers persisted in the control village near by.

Animals↗

PubMed1963

OBSERVATIONS ON HUMAN EXPOSURE TO THE ORGANOPHOSPHORUS INSECTICIDE FENTHION IN NIGERIA.

The search for substitutes for chlorinated hydrocarbon insecticides has led to the trial of organophosphorus compounds. Fenthion is promising as a residual spray in malaria eradication, but information on its human toxicology is scanty. In the work reported in this paper the inhabitants of a Nigerian village have been studied during a trial of fenthion. Moderate depressions of plasma cholinesterase were observed for five weeks after spraying, though there was no effect on red blood cell cholinesterase. A search was also made for other possible effects, including measurements of peak expiratory flow rate. No serious toxic effects were found.

Environment↗

PubMed1979

The safety of fenthion 29% m/v when applied topically to pregnant cows.

A pilot trial was conducted with fenthion 20% m/v to determine possible abortifacient or other toxic effects when applied to 4 1/2 month pregnant beef cows. No abortions or other clinical symptoms which could be attributed to the fenthion were observed after two topical applications, at a 3-week interval, of up to 5 times the therapeutic dose.

Abortion, Veterinary↗

PubMed1981

Possible fenthion toxicity in magpies (Pica pica).

Unusual mortality in magpies (Pica pica) is described. Dead or sick birds were discovered in proximity to cattle in Alberta feedlots. Subsequent examinations indicated magpies were being exposed to fenthion, an organophosphate used on cattle for control of warble larvae and lice. The possibility of toxicity with fenthion is suggested.

Animals↗

PubMed1993

[The effect of organophosphorus pesticide (fenthion) on GABA-cells in the central nuclei].

Organophosphorus pesticide (OP) produces abnormal eye movements. This is possibly due to an inhibition of central cholinergic neurons as well as GABAnergic neurons. Using anti-GABA-antibody, the authors studied the effect of OP on GABA-positive cells in the central nervous system. Fenthion (dimethyl 4-methylthion-m-tolyl-phosphorothionate, 20 mg/kg body weight), was given subcutaneously to the dorsal portion of Wistar rats for 30 days. After staining, the number of GABA-positive cells were counted at the superior colliculus (SC), the cerebellum, and the substantia nigra reticularis (SNR) on day 6, 10, 14, 18, 22, 26 and 30 respectively. The number of GABA-positive cells reduced in the cerebellum, SNR and SC decreasing remarkably after the initiation of fenthion administration. The number of GABA-positive cells also decreased in lateral geniculate nucleus and pretectal nuclei. Those results suggest that the reduction of GABA-positive cells produces abnormal eye movements in human OP intoxication.

Animals↗

PubMed1977

Altered sensitivity to acetylcholine during chronic administration of organophosphorus anticholinesterase (fenthion) in albino mice.

Tissue sensitivity to acetylcholine during chronic administration of fenthion was assessed in mice. Fenthion was injected intra-muscularly every fourth day and experiments were carried out at various intervals. The parameters selected for testing cholinergic effects were, acetyl choline-induced contraction of isolated ileum and salivary secretion in vivo. In both types of experiments an initial supersensitivity followed by tolerance to acetylcholine were observed. The underlying mechanisms are discussed.

Acetylcholine↗

PubMed1997

Effects of fenthion, isoxathion, dichlorvos and propaphos on the serum cholinesterase isoenzyme patterns of dogs.

The serum cholinesterase (ChE) isoenzyme patterns consist of 5 bands for normal beagle dogs. We examined the ChE isoenzyme patterns and ChE activities of 4 groups, each of which consisted of 4 dogs, given the organophosphate (OP) compounds fenthion (P = S type), isoxathion (P = S type), dichlorvos (P = O type) or propaphos (P = O type) po at 220, 75, 120 or 90 mg/kg respectively. Blood samples were collected for 30 d after the OP administrations. ChE isoenzyme bands 4 and 5 were inhibited 12 h after fenthion and isoxathion administration; dichlorvos and propaphos produced suppression of main bands 4 and 5 20 min after administration. This change was effective to differentiate the type of OP administered (P = S and P = O), while the main ChE isoenzyme bands of dog serum reflected inhibition of serum ChE activity.

Animals↗

PubMed1997

Field evaluation of biodegradable controlled release formulation of fenthion against Mansonia mosquitos.

Controlled release monolithic formulation of fenthion, an organophosphorus mosquito larvicide, prepared by the physical entrapment of the active agent into biodegradable polymer matrices was evaluated against Mansonia mosquito larvae breeding in hydrophytes infested coconut husk retting ponds. Field evaluation was carried out at two application rates viz, 2.5 and 1.0 ppm. Absolute control of larval breeding was observed for 25 and 17 weeks and over 50% reduction in breeding density was observed for another 3 and 2 weeks for the respective application rates of 2.5 and 1.0 ppm. The bioassay carried out with the water samples collected from the ponds treated at 2.5 ppm against the fourth instar larvae of Mansonia annulifera showed larval mortality of more than 95% for 14 weeks and 80-95% from 15 to 25th week. The concentration of fenthion in the treated ponds was found to vary between 0.006 and 0.095 ppm during the evaluation period.

Animals↗

PubMed1970

Inheritance of resistance to fenthion in Culex pipiens fatigans Wied.

The insecticide fenthion, which shows great promise for controlling the filariasis vector Culex pipiens fatigans, has been found in the laboratory to induce a certain amount of resistance. As the biochemical nature of fenthion resistance was known to be due to an increase in a particular esterase activity, the inheritance of the character was investigated in the present study. It was found to be mainly due to a single slightly recessive gene associated with linkage-group 2, and the increase in detoxifying esterase activity showed a similar inheritance.

Animals↗

PubMed1993

Genetic characterization of the Pto locus of tomato: semi-dominance and cosegregation of resistance to Pseudomonas syringae pathovar tomato and sensitivity to the insecticide Fenthion.

The Pto locus governs resistance to bacterial speck disease in tomato caused by race 0 strains of Pseudomonas syringae pathovar tomato (Pst). Large populations segregating for the Pto locus were generated and genetically characterized. Analysis of the locus has revealed that Pto acts in a semi-dominant manner and cosegegrates with sensitivity to an organophosphorous insecticide, Fenthion, suggesting that Pto may be a complex locus responsible for both phenotypes. We have redefined its map position on chromosome five of the classical genetic map and assigned its position on the molecular map, thus facilitating the alignment of the two genetic maps of the short arm of chromosome five of tomato. Furthermore, we have screened random amplified polymorphic (RAPD) markers for their ability to differentiate near-isogenic lines that differ only with respect to Pto and have identified and mapped seven of these markers. Our results suggest that Pto may be located in a euchromatic region on chromosome five which will be advantageous for the cloning of this locus by one of several molecular strategies.

Base Sequence↗

PubMed1979

Gill lesions in Cichlid fishes after intoxication with the insecticide Fenthion.

The toxic effects of Fenthion on the gills of Cichlid fishes were investigated. In Herotilapia multispinosa hyperplasia and separation of the respiratory epithelium, lamellar telangiectasis and thrombosis occurred. The lamellar epithelium of surviving fish regenerated in all cases. In Tilapia leucosticta no telangiectasis was found, but all the secondary lamellae were fused due to the severe hyperplasia of the gill epithelium.

Animals↗

PubMed1983

Effects of fenthion on the blood and tissue chemistry of a teleost fish (Heteropneustes fossilis).

Exposure of a freshwater teleost, Heteropneustes fossilis, to a concentration of 14 . 625 mg per 1 (0.9 of 96 h LC50) fenthion induced muscle and hepatic glycogenolysis with concomitant hyperglycaemia at 2, 6, 12 and 48 h after treatment. The pesticide evoked an initial fall (at 2 and 6 h) and later a rise (at 48 and 96 h) in blood chloride concentration. The treatment also caused anaemia with simultaneous increase in ESR and hypo-coagulability of whole-blood. The results are compared with organophosphate poisoning in this and in other fish species.

Animals↗

PubMed1988

Neuromuscular effects of chronic exposure to fenthion in dogs and predictive value of electromyography.

Chronic exposure to organophosphates (OP) can result in nonspecific neurologic signs in both man and animals. Improved methods are needed to predict toxicity and to better characterize neuromuscular effects. In this study, dogs were exposed to an OP (fenthion) by weekly dermal application of a 20% solution at a dosage of 44 mg/kg. This dosage does not produce signs of acute OP toxicity in dogs, although plasma cholinesterase (ChE) levels are significantly decreased. Electromyograms (EMG) were used to monitor motor unit potential (MUP) activity at minimal and submaximal contractile effort in four different muscles. At 1-month intervals, muscle biopsies were obtained and plasma ChE levels were determined. At 3 months, hyperreflexia and/or mild proprioceptive deficits were observed. The dosage was reduced to 22 mg/kg for the remaining 3 months of the study. At the end of this 6-month study, nerve and muscle biopsies were obtained. Mean plasma ChE levels were decreased (preexposure value of 1775 IU/liter to low of 310 IU/liter) and correlated with duration of exposure and change in dosage level. Fourier analysis of EMG indicated some increase in higher frequency components of the power spectrum with time, and analysis of individual MUPs revealed a significant (p less than 0.05) increase in the product of the amplitude times the duration of the potentials in all muscles examined. Biopsy results were supportive of EMG findings of altered neuromuscular function and loss of small motor units. The EMG changes were most consistent in the gastrocnemius muscle and were detected prior to development of clinical signs. These results indicate that EMG can be useful in monitoring OP exposure and predicting toxicity.

Animals↗

PubMed1989

Release and metabolism of dopamine in a clonal line of pheochromocytoma (PC12) cells exposed to fenthion.

The effects of an organophosphate (OP) pesticide, fenthion (FEN), on the release and metabolism of dopamine were evaluated in a clonal line of rat pheochromocytoma (PC12) cells. HPLC was used to determine media concentrations of DA and the DA metabolites norepinephrine (NE), 3,4-dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA). The FEN formulation solvent did not significantly affect DA metabolism. In the first study, cultures were treated with 10(-5) or 10(-6) M FEN or 10(-5) M neostigmine, a non-OP acetylcholinesterase inhibitor. Concentrations of both catecholamines were elevated in cultures treated with 10(-5) M FEN by 2.8-fold for DA and 3.5-fold for NE. Neostigmine effects were of smaller magnitude and DA was decreased after 24 hr. Cultures were also treated with depolarizing levels of K+, but the effect of FEN was not altered, suggesting that FEN does not act by increasing DA release. In the second study, the effect of 10(-6) M FEN was evaluated in cultures treated with the DA uptake inhibitor benztropine, the monoamine oxidase (MAO) inhibitor pargyline, or the catechol-O-methyltransferase (COMT) inhibitor tropolone. Inhibitor effects were consistent with their known mechanisms of action. In all cultures treated with FEN, the ratio HVA/DOPAC was decreased after 3 and 6 hr of exposure. A decrease in HVA/DOPAC was also observed in cultures treated with neostigmine and tropolone. In combination with pargyline, FEN decreased DA in contrast to its usual effect of increasing DA. Neither the stimulation of DA release nor the inhibition of DA uptake affected the observed action of FEN in PC12 cultures.(ABSTRACT TRUNCATED AT 250 WORDS)

3,4-Dihydroxyphenylacetic Acid↗

PubMed1988

Effects of fenthion, fenitrothion and desbromoleptophos on gait, acetylcholinesterase, and neurotoxic esterase in young chicks after in ovo exposure.

Previous studies have demonstrated that gait is affected in chicks exposed to organophosphorus esters (OPs) that induce delayed neurotoxicity (OPIDN) in adult hens. To investigate the developmental relationship between such functional deficits and OPIDN, chicks were exposed to 3 OPs with different OPIDN potential. Desbromoleptophos (DBL) induces OPIDN in adult hens; fenthion (FEN) has uncertain OPIDN potential; fenitrothion (FTR) does not induce OPIDN. Chicks were treated by injection into the egg on day 15 of incubation, after the presumed period of OP-induced structural teratogenesis. AChE and neurotoxic esterase (NTE) were assayed during incubation and in parallel with post-hatching evaluations of gait. DBL, 125 mg/kg in ovo, caused paralysis in 70% of chicks after hatching. The gait of surviving chicks was affected for at least 6 weeks and marked by toes curling under. NTE was inhibited until 10 days post-hatching and AChE until hatching. FEN did not inhibit NTE significantly, but AChE was significantly inhibited until hatching. Chicks exposed as embryos to FEN were hyperactive and aggressive. Gait was still affected 6 weeks after treatment with 3 mg/kg FEN. FTR at 125 mg/kg inhibited AChE until day 10 post-hatching, but neither inhibited NTE nor affected gait. The growth of OP-exposed chicks was not significantly decreased, so the decreased length and increased width of the stride could not be ascribed to stunted growth. We conclude that OPs cause irreversible effects on gait that are not related to their defined neurotoxic effects, since altered gait (1) occurs below the age of sensitivity to OPIDN, (2) is seen in the absence of NTE inhibition and (3) does not invariably accompany AChE inhibition.

Animals↗

PubMed2006

Development and single-laboratory validation of a new gas chromatographic multi-pesticide method of analysis of commercial emulsifiable concentrate formulations containing alachlor, chlorpyrifos methyl, fenthion and trifluralin as active ingredients.

A multi-pesticide (MP) method was developed and single-laboratory validated for the quality control of commercial pesticide products containing alachlor, chlorpyrifos methyl, fenthion and trifluralin as active ingredients (a.i.). A capillary gas chromatographic system with flame ionization detection (FID) and a programmable temperature vaporising split injector was used. The performance characteristics (specificity, linearity, precision and repeatability) of the method satisfied international acceptability criteria.

Acetamides↗

PubMed2004

New insights into the photoreactivity of the organophosphorus pesticide fenthion: a sigma aryl cation as a key intermediate in the photodecomposition.

The primary photodegradation processes of fenthion (FN), one of the most photosensitive pesticides used in agriculture, have been investigated by combining laser flash photolysis and steady-state measurements. The triplet state of FN is produced quite efficiently (Phi(isc) approximately 0.3). However, this excited state does not seem to trigger the primary photodecomposition pathways of the pesticide. It is demonstrated that FN undergoes photoheterolysis via the excited singlet state and gives the corresponding singlet "sigma aryl cation". Chemical evidence for the generation of this transient species is given by trapping with typical "sigma nucleophiles" such as chloride and methanol. This photodegradation mechanism is, in part, quite different with respect to what is known to date and may account for the formation of the O,O-dimethyl S-[3-methyl-4-(methylthio)phenyl] phosphorothioate discovered as a novel photodegradation product of FN.

Cations↗