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Chemical Research in Toxicology 1996O,O,S-Trimethyl phosphorodithioate and phosphorothiolate [(MeO)2P(S)SMe and (MeO)2P-(O)SMe, respectively are known from earlier studies to be impurities, delayed...
O,O,S-Trimethyl phosphorodithioate and phosphorothiolate [(MeO)2P(S)SMe and (MeO)2P-(O)SMe, respectively are known from earlier studies to be impurities, delayed toxicants, and detoxication inhibitors in several major O,O-dimethyl phosphorodithioate insecticides. Our recent studies show extensive S-methylation of mono- and dithiocarbamic acids in mice, suggesting the possibility that phosphorodithioic acids such as (MeO)2P(S)SH might also undergo S-methylation. This possibility was examined in ip-treated mice with emphasis on the metabolites of dimethoate [(MeO)2P(S)SCH2C(O)NHMe], one of the most important organophosphorus insecticides. The urinary metabolites of dimethoate, which contains no P-SMe substituent, were found to include four compounds with P-SMe moieties identified by 31P NMR spectroscopy as MeO(HS)P(O)SMe, MeO(HO)P(O)SMe, (MeO)2P(S)SMe, and (MeO)2P-(O)SMe; the latter two compounds are also established by GC-MS as dimethoate metabolites in mouse urine, liver, kidney, and lung. Several approaches verified unequivocally that the previously unknown P-SMe metabolites in urine and tissues are due to in vivo S-methylation rather than to impurities. Studies with other O,O-dimethyl and O,O-diethyl phosphorodithioate insecticides established the analogous S-methylation pathway for ethion, malathion, phenthoate, phosalone, and phosmet in mice. Thus, metabolism of O,O-dialkyl phosphorodithioate insecticides in mammals is shown here for the first time to yield S-methyl phosphorodithioates and phosphorothiolates from in vivo S-methylation of the intermediate O,O-dialkyl phosphorodithioic acids.
Topics: Animals; Dimethoate; Male; Methylation; Mice; Organothiophosphates; Organothiophosphorus Compounds; Pesticides; Triazenes
PubMed: 8902277
DOI: 10.1021/tx9600715 -
Ecotoxicology and Environmental Safety Jun 1995Histopathological changes in the intestine of Channa punctatus induced by chronic nonlethal levels of Elsan (211 ppb), mercury (16.7 ppb), and ammonia (15.64 ppm) were...
Histopathological changes in the intestine of Channa punctatus induced by chronic nonlethal levels of Elsan (211 ppb), mercury (16.7 ppb), and ammonia (15.64 ppm) were studied at 7-day intervals for 90 days and the data were presented only for days (7, 28, 63, and 90) when the most conspicuous changes were noted after treatment. In the earlier phases of Elsan treatment (7 and 28 days) overall destruction of the structure of villus and other layers was prominent. Histopathology of the intestine of C. punctatus, after 63-day Elsan exposure, could be described as collapsed villi with the tips merged with each other to give a flattened appearance. Ninety-day Elsan exposure demonstrated severe damage in the longitudinal muscle layer. After 7-day mercury treatment a high degree of necrosis was indicated by submucosal area, whereas 28-day mercury treatment revealed collapsed villi due to necrotic mucosal cells and goblet cells. Mercury treatment for 63 days caused disarray of all the layers, but some improvement of villus organization was noted in fish treated with mercury for 90 days. Seven-day exposure to ammonia deteriorated the normal structure of the villus, whereas in 28-day ammonia exposure, lesions were predominant in the submucosal layers. Sixty-three-day ammonia treatment demonstrated an effect similar to that produced by Elsan, associated with a more complete destruction of all the layers. Fishes under ammonia treatment for 90 days demonstrated extensive damage to the mucosal folds. The major changes in thickness of different layers of the intestine were also evaluated.(ABSTRACT TRUNCATED AT 250 WORDS)
Topics: Ammonia; Animals; Fishes; Insecticides; Intestine, Small; Mercury; Organothiophosphorus Compounds; Time Factors; Water Pollutants, Chemical
PubMed: 7544266
DOI: 10.1006/eesa.1995.1044 -
Lack of promoting activity of four pesticides on induction of preneoplastic liver cell foci in rats.Teratogenesis, Carcinogenesis, and... 1995Four pesticides were examined for hepatopromoting activity using a medium-term bioassay based upon induction of glutathione S-transferase placental form (GST-P) positive...
Four pesticides were examined for hepatopromoting activity using a medium-term bioassay based upon induction of glutathione S-transferase placental form (GST-P) positive foci in the rat liver. Male F344 rats were initially injected with diethylnitrosamine (DEN; 200 mg/kg body weight) intraperitoneally and 2 weeks later were treated with O-ethyl O-4-nitrophenyl phenylphosphonothioate (EPN; 75 and 150 ppm), diazinon (500 and 1,000 ppm), phenthoate (500 and 1,000 ppm), or iprobenfos (500 and 1,000 ppm) in the diet for 6 weeks and then killed, all rats being subjected to partial hepatectomy at week 3. All of the pesticides gave negative results, the numbers and areas of GST-P positive foci not exceeding the control values for animals given DEN alone. Indeed, a significant reduction of foci development was seen for EPN (75 ppm). These findings provide experimental evidence that the presently examined four pesticides do not have hepatocarcinogenic potential in rats.
Topics: Animals; Carcinogens; Diazinon; Diethylnitrosamine; Liver Neoplasms, Experimental; Male; Organothiophosphorus Compounds; Pesticides; Phenylphosphonothioic Acid, 2-Ethyl 2-(4-Nitrophenyl) Ester; Precancerous Conditions; Rats; Rats, Inbred F344
PubMed: 8867880
DOI: 10.1002/tcm.1770150504 -
Ecotoxicology and Environmental Safety Dec 1994Histopathological changes in the head and trunk kidneys of Channa punctatus induced by chronic nonlethal levels of Elsan (211 ppb), mercuric chloride (16.7 ppb), and...
Histopathological changes in the head and trunk kidneys of Channa punctatus induced by chronic nonlethal levels of Elsan (211 ppb), mercuric chloride (16.7 ppb), and aqueous ammonia (15.64 ppm) were studied on 7, 28, 63, and 90 days of exposure. The pathology of the head kidney was characterized by degeneration and dispersion of interrenal and chromaffin tissue and necrosis in the haemopoietic elements. Kidney lesions were observed throughout the entire experimental period in fish exposed to Elsan and mercuric chloride. In contrast, the lesion induced by exposure to aqueous ammonia began to heal during the first phase of treatment. Marked abnormalities in trunk kidney histology were also found. Renal lesions consisted of minimal to mild multifocal, acute tubular epithelial degeneration, karyolysis, and dilation or shrinkage of Bowman's capsule and glomerulus. Elsan treatment resulted in a highly significant decrease in the dimension of Bowman's capsule and glomerulus at all days of sampling, except on Day 28. The response of the fish trunk kidney tissue to mercuric chloride was similar to that observed with Elsan exposure in terms of the alteration in the mean dimensions of Bowman's capsule and glomerulus. The response to ammonia was significant reduction in the size of Bowman's capsule and glomerulus throughout the experimental period except at Day 28. Little dilation of Bowman's capsule and a significant dilation of glomerulus were found at Day 28 of ammonia exposure. This study demonstrated that a chronic nonlethal exposure to Elsan, mercuric chloride affect both endocrine and excretory parts of the kidney while ammonia specifically damages the excretory part of the kidney of C. punctatus.
Topics: Ammonia; Animals; Dose-Response Relationship, Drug; Fishes; Insecticides; Kidney; Kidney Glomerulus; Mercury; Organothiophosphorus Compounds; Time Factors
PubMed: 7534687
DOI: 10.1016/0147-6513(94)90003-5 -
Journal of Toxicology. Clinical... 1994Five metabolites were detected in the plasma and urine of a patient following ingestion of the organophosphate insecticide, phenthoate. Intact phenthoate was detected...
Five metabolites were detected in the plasma and urine of a patient following ingestion of the organophosphate insecticide, phenthoate. Intact phenthoate was detected only in gastric lavage fluid. After methylation of acidic extracts of plasma and urine, phenthoate acid, demethyl phenthoate, demethyl phenthoate oxon acid, demethyl phenthoate S-isomer, and demethyl phenthoate acid S-isomer were identified with synthesized phenthoate analogues by gas chromatography and gas chromatograph-mass spectrometry. The main metabolites were phenthoate acid and demethyl phenthoate oxon acid. Although demethyl phenthoate oxon acid was a significant metabolite, no phenthoate oxon, phenthoate oxon acid or demethyl phenthoate oxon were detected. If the oxon was formed in the patient, it may have been rapidly degraded by carboxylesterase or glutathione transferase to demethyl phenthoate oxon acid.
Topics: Chromatography, Gas; Humans; Insecticides; Male; Middle Aged; Organothiophosphorus Compounds; Poisoning
PubMed: 8308949
DOI: 10.3109/15563659409000430 -
Ecotoxicology and Environmental Safety Apr 1989Histopathological changes were induced in the ovary by chronic nonlethal levels of Elsan (211 ppb), mercury (16.7 ppb), and ammonia (15.64 ppm). In the breeding season,...
Histopathological changes were induced in the ovary by chronic nonlethal levels of Elsan (211 ppb), mercury (16.7 ppb), and ammonia (15.64 ppm). In the breeding season, treated Channa punctatus revealed a significant decrease in ovarian weight throughout the duration of the experiment. Acute changes were noted in the diameter and percentage occurrence of the different stages of oocytes. In all cases, stage I oocytes revealed no difference in diameter with respect to control although they demonstrated an increase in the percentage occurrence. For stages II and III, a remarkable decrease occurred in both the number and the diameter of these mature oocytes. The preponderance of stage I and destruction of stage II and stage III oocytes in all three treatments indicate that chemically diverse xenobiotics have equal reproductive toxicity in fish, interfering with their breeding.
Topics: Ammonia; Animals; Female; Fishes; Mercury; Oocytes; Organothiophosphorus Compounds; Ovary; Water Pollutants; Water Pollutants, Chemical
PubMed: 2737117
DOI: 10.1016/0147-6513(89)90044-4 -
Ecotoxicology and Environmental Safety Feb 1989Inhibition of acetylcholinesterase (AChE) and accumulation of acetylcholine were observed in tissues of fish, Channa punctatus, during carbaryl and/or phenthoate...
Inhibition of acetylcholinesterase (AChE) and accumulation of acetylcholine were observed in tissues of fish, Channa punctatus, during carbaryl and/or phenthoate toxicity. Carbaryl in combination with phenthoate exerted synergism on the AChE system during their interaction.
Topics: Acetylcholinesterase; Animals; Carbaryl; Cholinesterase Inhibitors; Fishes; Insecticides; Organothiophosphorus Compounds
PubMed: 2496969
DOI: 10.1016/0147-6513(89)90003-1 -
Biomedical and Environmental Sciences :... Jun 1988Phenthoate- and carbofuran-containing insecticides are widely used by Indian farmers, thus endangering fish by exposing them to the hazards of a chronic low dose of... (Comparative Study)
Comparative Study
Phenthoate- and carbofuran-containing insecticides are widely used by Indian farmers, thus endangering fish by exposing them to the hazards of a chronic low dose of these xenobiotics. Channa punctatus, cultivated under paddy-cum-fish culture programs, was treated with 176 ppb phenthoate, 333 ppb carbofuran, or a mixture of 88 ppb phenthoate plus 250 ppb carbofuran for 15 days. The rate of mortality was 10% in all treatments. These xenobiotics caused significant inhibition of brain acetylcholinesterase concomitant with low kidney iodide peroxidase activity and depressed blood thyroxine levels. It is surmised that phenthoate and carbofuran compounds are capable of significantly influencing the hormonal status of fish which is mediated via their target action on the nervous system.
Topics: Acetylcholinesterase; Animals; Brain; Carbofuran; Cholinesterase Inhibitors; Drug Combinations; Fishes; India; Insecticides; Iodide Peroxidase; Kidney; Organothiophosphorus Compounds; Radioimmunoassay; Spectrophotometry; Thyroxine
PubMed: 3268109
DOI: No ID Found -
Environmental Pollution (Barking, Essex... 1988The effects of the herbicide (2,4-D) and six organophosphorus insecticides (Diazinon, Dimethoate, Fenitrothion, Malathion, Phenthoate and Quinalphos) on growth,...
The effects of the herbicide (2,4-D) and six organophosphorus insecticides (Diazinon, Dimethoate, Fenitrothion, Malathion, Phenthoate and Quinalphos) on growth, photosynthesis and chlorophyll a synthesis of the fresh water green alga Chlamydomonas reinhardtii (mt +) were studied. At low concentrations (1 and 5 ppm), the herbicide and all six orgnophosphorus insecticides stimulated photosynthesis of the alga. The stimulating effects on algal growth and chlorophyll a synthesis were only observed in the presence of low concentration (1 ppm) of 2,4-D and Fenitrothion, Growth, photosynthesis and chlorophyll a synthesis of the alga were inhibited in the presence of high concentrations (10, 20 and 40 ppm) of the herbicide and all the six organophosphorus insecticides. Results also indicated that the toxicities of these organophosphorus insecticides on the tested alga were dependent on their chemical structures.
PubMed: 15092501
DOI: 10.1016/0269-7491(88)90151-0 -
Medicine, Science, and the Law Oct 1986
Topics: Chromatography, Gas; Humans; Male; Mass Spectrometry; Middle Aged; Organothiophosphorus Compounds
PubMed: 3784847
DOI: 10.1177/002580248602600403