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PubMedDate not supplied

Carbamate poisoning: high resolution CT and pathologic findings.

Carbamate insecticides are commonly used agricultural insecticides. The major cause of morbidity and mortality in acute carbamate poisoning is respiratory failure associated with pulmonary edema. Although carbamate poisoning is well recognized in the clinical literature, the findings of high resolution CT (HRCT) with carbamate have not been reported. We report the radiographic and HRCT findings of a patient with acute carbamate poisoning who had pathologically proven interstitial pneumonitis after resolution of initial pulmonary edema.

Acute Disease↗
PubMed2001

Agricultural exposure to carbamate pesticides and risk of non-Hodgkin lymphoma.

Recent epidemiological studies have suggested an increased risk of non-Hodgkin lymphoma (NHL) from carbamate insecticide use among farmers. To further explore the possible relationships, we conducted a pooled analysis of three population-based case-control studies conducted in four midwestern states in the United States. A total of 985 white male subjects and 2895 control subjects were included in this analysis. Unconditional logistic regression was used to estimate the association and control for confounding. Compared with nonfarmers, farmers who had ever used carbamate pesticides had a 30% to 50% increased risk of NHL, whereas farmers without carbamate pesticide use showed no increased risk. Analyses for individual carbamate pesticides found a more consistent association with Sevin but not carbofuran, butylate, or S-ethyl dipropylthiocarbamate plus protectant. Among farmers using Sevin, the risk of NHL was limited to those who personally handled the product, those who first used the product for > or = 20 years before their disease diagnosis, and those who used the product for a longer period. These associations persisted after adjusting for other major classes of pesticides. These results suggest an increased risk of NHL associated with carbamate pesticide use, particularly Sevin. Further investigation of the association is warranted.

Adult↗
PubMed1999

Carbamate kinase: New structural machinery for making carbamoyl phosphate, the common precursor of pyrimidines and arginine.

The enzymes carbamoyl phosphate synthetase (CPS) and carbamate kinase (CK) make carbamoyl phosphate in the same way: by ATP-phosphorylation of carbamate. The carbamate used by CK is made chemically, whereas CPS itself synthesizes its own carbamate in a process involving the phosphorylation of bicarbonate. Bicarbonate and carbamate are analogs and the phosphorylations are carried out by homologous 40 kDa regions of the 120 kDa CPS polypeptide. CK can also phosphorylate bicarbonate and is a homodimer of a 33 kDa subunit that was believed to resemble the 40 kDa regions of CPS. Such belief is disproven now by the CK structure reported here. The structure does not conform to the biotin carboxylase fold found in the 40 kDa regions of CPS, and presents a new type of fold possibly shared by homologous acylphosphate-making enzymes. A molecular 16-stranded open beta-sheet surrounded by alpha-helices is the hallmark of the CK dimer. Each subunit also contains two smaller sheets and a large crevice found at the location expected for the active center. Intersubunit interactions are very large and involve a central hydrophobic patch and more hydrophilic peripheral contacts. The crevice holds a sulfate that may occupy the site of an ATP phosphate, and is lined by conserved residues. Site-directed mutations tested at two of these residues inactivate the enzyme. These findings support active site location in the crevice. The orientation of the crevices in the dimer precludes their physical cooperation in the catalytic process. Such cooperation is not needed in the CK reaction but is a requirement of the mechanism of CPSs.

Arginine↗
PubMed1993

Mechanisms of action of cephalosporin 3'-quinolone esters, carbamates, and tertiary amines in Escherichia coli.

Cephalosporin 3'-quinolone esters, carbamates, and tertiary amines are potent antibiotics whose antibacterial activities reflect the action of both the beta-lactam and the quinolone components. The biological properties of representative compounds from each class were compared in Escherichia coli. All compounds bound to the essential PBP 3, inhibited DNA gyrase, and caused filamentation in growing cells. To distinguish between cephalosporin- and quinolone-induced filaments, nucleoid segregation was also examined, as quinolones disrupt nucleoid segregation while the beta-lactams do not (N. H. Georgopapadakou and A. Bertasso, Antimicrob. Agents Chemother. 35:2645-2648, 1991). The cephalosporin quinolone esters Ro 23-9424 and Ro 24-6392, at concentrations causing filamentation in E. coli ATCC 25922, did not affect nucleoid segregation after 1 h of incubation (cephalosporin response) but did not affect it after 2 h (quinolone response), indicating the release of free quinolone. Accordingly, only the quinolone response was produced in a strain possessing TEM-3, an expanded-spectrum beta-lactamase. The cephalosporin carbamate Ro 24-4383 and the tertiary amine Ro 24-8138 produced a quinolone response in E. coli ATCC 25922, though they produced a cephalosporin response in a quinolone-resistant strain. Carbamate and tertiary amine linkages are chemically more stable than the ester linkage, and both cephalosporin 3'-quinolone carbamates and tertiary amines are more potent inhibitors of DNA gyrase than are the corresponding esters. The results suggest that, while intact cephalosporin 3'-quinolone esters act as cephalosporins, carbamates and amines may possess both cephalosporin and quinolone activity in the intact molecule.

Amines↗
PubMed2001

[Formation of ethyl carbamate in umeshu (plum liqueur)].

Samples of umeshu, a Japanese plum liqueur made from unripe plums, shochu and crystal sugar, were stored under fluorescent light, in the dark and in the refrigerator. The amount of ethyl carbamate formed in umeshu exposed to light or room temperature was larger than that in the dark or at low temperature. The amount of ethyl carbamate formed in umeshu to which cyanide had been added was larger than that in the absence of added cyanide. Thus, the amount of ethyl carbamate formed in the umeshu was increased by not only light and higher temperature, but also cyanide. Samples of model alcoholic beverages were stored under various conditions using red, yellow and blue cellophanes. The amount of ethyl carbamate formed in the model alcoholic beverage with blue cellophane was larger than in the cases of red and yellow cellophanes. It was found that the amount of ethyl carbamate formed in the model alcoholic beverage was increased by light in the wavelength range of 375-475 nm.

Alcoholic Beverages↗
PubMedDate not supplied

Determination of ethyl carbamate in distilled alcoholic beverages by gas chromatography with flame ionization or mass spectrometric detection.

Quantitative methods are detailed for determination of ethyl carbamate in distilled alcoholic beverages by capillary gas chromatography with flame ionization detection (GC/FID) and by packed-column gas chromatography/mass spectrometry (GC/MS) using selected ion monitoring. Five g samples of distillate of known ethanol concentration are diluted with water to 25% ethanol (v/v), washed with petroleum ether, and extracted with dichloromethane prior to GC/FID or GC/MS analysis. As necessary, sample extracts that exhibit GC/FID interference are passed through alumina for additional cleanup. When internal standards (tert-butyl carbamate and n-butyl carbamate for GC/FID, or ethyl 13C-15N-carbamate for GC/MS) were used for quantitation, the limit of detection for ethyl carbamate was in the range of 5-25 ppb. Coefficients of variation ranged from 3.5 to 6.0% for GC/FID determinations, and from 1.4 to 3.2% for GC/MS. Correlation between methods for 22 random distillate samples ranging in concentration from approximately 40 to 800 ppb gave a correlation coefficient (r) of 0.996.

Alcoholic Beverages↗
PubMed1965

STUDIES ON THE INHERITANCE OF CARBAMATE-RESISTANCE IN THE HOUSEFLY (MUSCA DOMESTICA L.).

In view of the increasing importance of carbamic acid esters in insect control, the authors have conducted studies on the inheritance of carbamate-resistance in the housefly Resistance to Isolan (1-isopropyl-3-methyl-5-pyrazolyl dimethylcarbamate) in carbamate-selected strains is inherited as a partially dominant major single factor, without sex linkage or appreciable cytoplasmic influence. Inclusion of piperonyl butoxide as a synergist with Sevin (1-naphthyl methylcarbamate), Zectran (4-dimethylamino-3,5-xylyl methylcarbamate), or m-isopropylphenyl methylcarbamate also produced evidence of monofactorial inheritance.In contrast, resistance to Isolan and to a combination of Sevin and piperonyl butoxide in a ronnel-selected strain is inherited in a pattern suggestive of a polygenic system.The results obtained are discussed in the light of previously established data on the rate of development, stability and regression of carbamate-resistance.

Animals↗
PubMed1979

Studies on drug metabolism by use of isotopes. XXIV-Determination of 3-phenylpropyl carbamate metabolites using stable isotope labelling with deuterium or carbon-13.

Metabolism of 3-phenylproply carbamate was investigated by using a stable isotope tracer technique. 3-Phenylpropanol, 3-hydroxy-3-phenylpropanol, 3-hydroxy-3-phenylpropyl carbamate, 2,3-dihydroxy-3-phenylproply carbamate, benzoic acid and hippuric acid were identified as the rat urinary metabolites. Using the dilution analysis, the amounts of metabolites in urine and faeces in rat and man were determined. In rats, 2,3-dihydroxy-3-phenylproply carbamate and 3-phenylpropanol glucuronide were excreted into the urine as the major metabolites of this drug. On the other hand, in man, the major metabolite was hippuric acid and about 30% of the administered dose was excreted as hippuric acid in the 24 h urine. The tracer technique using a singly labelled drug with carbon-13 employed in the present study provided a reliable methods for the analysis of drug metabolites and was comparable with the tracer technique using a multilabelled drug with deuterium.

1-Propanol↗
PubMed2004

Efficacy of insecticide mixtures against larvae of Culex quinquefasciatus (Say) (Diptera: Culicidae) resistant to pyrethroids and carbamates.

The efficacy of insecticide mixtures of permethrin (pyrethroid) and propoxur (carbamate) was tested by larval bioassays on two strains of Culex quinquefasciatus (Say), one resistant to pyrethroids and the other resistant to carbamates. The method consisted in combining one insecticide at the highest concentration causing no mortality (LC0) with increasing concentrations of the second one. The concentration-mortality regression lines were determined for permethrin and propoxur alone and in combination, and synergism ratios (SR) were calculated in order to determine the magnitude of an increase or decrease in efficacy with use of the mixtures. With the pyrethroid-resistant strain (BK-PER), the results showed that propoxur at LC0 significantly enhanced the insecticidal activity of permethrin (SR50 = 1.54), especially on the upper range of the concentration-mortality regression. Conversely, when permethrin at LC0 was tested with propoxur against the carbamate resistant strain (R-LAB), an antagonistic effect was observed (SR50 = 0.67). With the BK-PER strain, an increased oxidative detoxification (MFO) appeared to be the main mechanism responsible for the synergistic interaction. Nevertheless, antagonism in the R-LAB strain is probably due to a physiological perturbation implying different target sites for pyrethroid (ie sodium channel) and carbamate insecticides [ie acetylcholinesterase (EC 3.3.3.7) and choline acetyltransferase (EC 2.3.1.6)].

Animals↗
PubMed1976

The effect of N-alkyl groups of substituted phenyl-N-alkyl carbamates on the inhibition of human plasma cholinesterase.

The inhibition constants for human plasma cholinesterase (dissociation, carbamylation, decarbamylation, overall bimolecular rate constants) were determined for two series of substituted phenyl-N-alkyl carbamates. N-propyl carbamates were found to be better inhibitors than the corresponding compounds carrying smaller N-alkyl groups. In both series the carbamylation constants of N-ethyl carbamates were lower than those of the N-methyl and N-propyl analogues, whereas the decarbamylation constants of the former were found to be higher than those of the latter carbamates. The experimental results obtained with human plasma cholinesterase are compared with published inhibition constants determined for several types of acetylcholinesterases.

Carbamates↗
PubMed1975

The excretion in urine of four insecticidal carbamates and their phenolic metabolites after oral administration to rats.

4 insecticidal carbamates: 3-methyl, 5-isopropylphenyl N-methyl-carbamate (Promecarb), 4-methylthio, 3,5 dimethylphenyl N-methylcarbamate (Mesurol), 4-dimethyl-amino, 3,5 dimethylphenyl N-methylcarbamate (Zectran), and 4-benzothienyl N-methyl-carbamate (Mobam) were orally administered to male Wistar rats. The excretion of the unchanged products was followed in 24 hrs urine collections. The corresponding phenols of the different carbamates could be identified as metabolites by gas-chromatography-mass spectrometyr. These metabolites were quantified afterward by gas-liquid chromatography. In all cases only minor quantities of unchanged products and metabolites were excreted in the urine over the 48 hrs after administration.

Administration, Oral↗
PubMed1979

[Determination of carbamate pesticides in fruits and vegetables by means of high pressure liquid chromatography (author's transl)].

It is shown that carbamate pesticides can be determined at the ppm level in different kinds of fruits and vegetables using high pressure liquid chromatography. The lower detection limit corresponding to a signal to noise ratio of three is between 0,025 and 0,25 ppm depending on the type of carbamate and plant material. In all cases it is below the maximum permissible value for pesticide residues. Due to the high separating power of high pressure liquid chromatography a simple sample pretreatment procedure can be used. The carbamates are extracted from the biological sample by dichloromethane and injected directly into the liquid chromatograph after replacing the extraction solvent by the mobile phase. In many cases a definite identification and quantitation of the carbamate is possible with a single chromatographic column. Some plants with a more complex matrix require a two-column operation in which the effluent fraction of the first column containing the pesticide is transferred by column switching to a second column in order to achieve a complete separation. The improved resolution in the two-column operation is caused by the relative enrichment effect of the fractionation and the increased column length.

Carbamates↗
PubMed1975

Uptake and excretion of organophosphorus and carbamate insecticides by fresh water fish, motsugo, Pseudorasbora parva.

Fresh water fish, Motsugo was reared in aquarium water tank containing about 1 ppm of 3 organophosphorus and 3 carbamate insecticides for about 30 days. The persistence of these insecticides in water and uptake and excretion of insecticides by fish were examined. Among organophosphorus insecticides, malathion is the most unstable in water, and degraded more than 99% for 7 days. Fenitrothion is moderately stable, and degraded 97% for 29 days. Diazinon is the most stable, and degraded 72% for 30 days. Among carbamates, carbaryl is the most unstable in water, and degraded more than 95% for 6 days. BPMC is moderately stable, and degraded 80% for 32 days. XMC is the most stable, and degraded 45% for 34 days. As for the uptake of the pesticides by fish, organophosphorus insecticides were generally higher than carbamate insecticides. The concentration of diazinon in fish reached to 211 ppm of the maximum level after 3 days, and that of fenitrothion reached to 162 ppm of the maximum level after 4 days. Afterwards, the concentration of both the insecticides decreased gradually due to the metabolism and excretion of the insecticides in fish. Uptake of malathion was very low and metabolized rapidly, and its concentration became to less than 0.01 ppm after 7 days. Among carbamate insecticides, the concentration of carbaryl in fish after one day reached to 7.5 ppm which was the maximum level of uptake. On the other hand, the concentration of BPMC in fish after 4 days became to 4.8 ppm, which was the maximum level, and decreased gradually. The concentration of XMC in fish was only 1.4 ppm after one day, but the metabolism rate of XMC in fish was fairly slow. Therefore, 0.55 ppm of XMC in fish remained even after 34 days. Moreover, in the test tank of diazinon, fenitrothion and BPMC, the appearance of deformed fish with spinal curvature of back bone came out at the rate of 10 to 30%.

Animals↗
PubMed1988

Carbon-13 isotope effects on reactions involving carbamate and carbamoyl phosphate.

Several 13C isotope effects of relevance to reactions involving carbamate and carbamoyl phosphate have been determined. The fractionation factor of carbamate relative to aqueous CO2 is 1.011; the equilibrium isotope effect on the reaction catalyzed by carbamate kinase is 0.9983. From these data we can calculate that the fractionation factor of carbamoyl phosphate relative to aqueous CO2 is 1.013. The kinetic 13C isotope effect on the decomposition of carbamoyl phosphate to cyanate and phosphate is 1.058. The environment of the carbon atom in carbamate and carbamoyl phosphate and the mechanism of carbamoyl phosphate decomposition are discussed in light of these values.

Carbamates↗
PubMed1983

Intracellular inorganic carbon exists as protein carbamate in photosynthesizing Euglena gracilis z.

The form of inorganic carbon accumulated in Euglena gracilis cells was determined. Euglena cell protein bound 0.96 nmol CO2/mg protein. The binding of CO2 was by the formation of protein carbamate as indicated by acid lability of the protein-CO2 complex, stimulation of complex formation by high ionic strength and the carbamate resonance in 13C-NMR spectrum. The protein carbamate could also be isolated from photosynthesizing Euglena. The formation of the carbamate required light energy fixed photosynthetically.

Animals↗
PubMed1979

Direct gas chromatographic determination of carbamate pesticides using Carbowax 20M-modified supports and the electrolytic conductivity detector.

The gas chromatographic behavior of 32 carbamate pesticides was investigated using the Hall electrolytic conductivity detector. Relative retention indices were successfully determined for 24 carbamates on six different columns. Columns investigated included Ultra-Bond, 3% OV-101 on Ultra-Bond, 1% OV-17 on Ultra-Bond, 1% OV-210 on Ultra Bond, 1% Carbowax 20M on Ultra-Bond and 0.5% OV-210 + 0.65% OV-17 on Ultra-Bond. Chemical-ionization gas chromatography-mass spectrometry was used to verify that the carbamates were chromatographed intact. Chemical-ionization mass spectra are reported. Analytical procedures are demonstrated for the determination of carbamate residue in soil.

Carbamates↗
PubMed1977

Mutagenicity screening of five methyl carbamate insecticides and their nitroso derivatives using mutants of Salmonella typhimurium LT2.

The mutagenic activity of five methyl carbamate insecticides-carbaryl, baygon, BUX-Ten, landrin and methomyl-and their nitroso derivatives were investigated using histidine auxotrophs-his TA98, his TA100, his TA1535, his TA1537 and his TA1538--of Salmonella typhimurium LT2 derived by Ames. The methyl carbamate insecticides did not cause a signficant increase in the number of revertant colonies in any of the strains used. In contrast, the nitroso derivatives of the carbamate insecticides greatly increased the number of colonies on plates inoculated with strains his TA100 and his TA1535. We conclude that the nitroso derivatives of the tested methyl carbamate insecticides are potent mutagens; whereas, the parent insecticides are non-mutagenic.

Carbamates↗
PubMed1984

Ferrocene-carbamate as prophylaxis against soman poisoning.

The effect of a carbamate derivative of ferrocene as a prophylactic agent toward soman poisoning was studied in mice. A sixfold decrease of the acute toxicity (24-hr LD50) of soman was obtained when the carbamate (5.5 mg/kg = 1/30 X LD50) was given intraperitoneally 30 min before soman. In this experiment atropine (20 mg/kg ip) was given 10 min before soman as support. The protection was lower when atropine or atropine plus toxogonin were given as therapy (1 min after soman). At these protective doses of the ferrocene -carbamate, a 30% inhibition of blood acetylcholinesterase activity was seen. Like physostigmine, the ferrocene -carbamate inhibited the brain acetylcholinesterase, suggesting that the compound entered the brain tissue.

Animals↗