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PubMed1988

Organochlorine pesticide residues in chicken eggs: a survey.

One hundred and five chicken egg samples were taken from seven geographical locations in Kenya and analyzed for organochlorine pesticide residues using gas-liquid chromatography. Nine organochlorine compounds were detected: alpha- and gamma-HCH/BHC (hexachlorocyclohexane/benzene hexachloride), aldrin, dieldrin, p,p'-DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene], p,p'-DDD (TDE) [2,2-bis(p-chlorophenyl)-1,1-dichloroethane] (tetrachlorodiphenylethane), o,p'-DDD [2-(o-chlorophenyl)-2-(p-chlorophenyl)-1,1-dichloroethane], o,p'-DDT [2-(o-chlorophenyl)-2-(p-chlorophenyl)-1,1,1-trichloroethane], and p,p'-DDT. Eighteen of the samples contained DDT levels exceeding the practical residue limit (0.5 ppm). The mean DDT residue content was 0.68 ppm, a result influenced greatly by the high contamination in the 18 samples. Both individual and mean residue levels for other organochlorine pesticides detected were well within the respective practical residue limits.

Animals↗
PubMed1989

Demographic and seasonal influences on human serum pesticide residue levels.

This study was intended to characterize more fully the distribution of serum concentrations of 16 pesticide residues with regard to key demographic and seasonal variables in a subsample of persons from the Second National Health and Nutrition Examination Survey between the ages of 12 and 74 yr old. Blood sera in 2-ml aliquots were analyzed, and the results were confirmed for 5994 persons. Almost all participants (99.5%) had p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) concentrations greater than or equal to 1 ppb, ranging as high as 378.6 ppb. For the other pesticide residues, only beta-benzene hexachloride (beta-BHC) (quantified in 17.2% of the sera), dieldrin (10.6%), and another DDT-related residue, p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT) (35.7%) were found at quantifiable levels in more than 10% of the serum specimens. Of the remaining analytes, hexachlorobenzene (HCB), trans-nonachlor (TNC), and heptachlor epoxide (HE) were found at quantifiable concentrations in 1-10% of the specimens, whereas o,p'-DDT, o,p'-DDE, p,p'-DDD, mirex, alpha-BHC, gamma-BHC, heptachlor, delta-BHC, and aldrin were found in less than 1% of the serum specimens. Results showed that increasing age, residing on a farm, or being a male conferred increased risks of exposure to most of the pesticide residues, independent of all other demographic and seasonal factors. In a pattern less consistent across the different pesticide residues and for fewer of the pesticides, persons who lived below the national poverty level, were nonwhite, resided in the South or West, or were examined in the spring or winter also seemed to have an increased likelihood of having quantifiable serum levels.

Adolescent↗
PubMed1995

Induction of cytochrome P-450 in the Norway rat, Rattus norvegicus, following exposure to potential environmental contaminants.

Cytochrome P-450 (CYP) induction (consisting of increases in cellular RNA and protein content and associated catalytic activities) occurs predominantly in the liver, but also in small intestine, lung, kidney, and placenta, of Norway rats (Rattus norvegicus) exposed to certain types of potential environmental contaminants. The specific isoform(s) induced in the rat and the magnitudes of the increases observed depend upon the chemical nature of the xenobiotic. For instance, the predominant isoforms induced by nonhalogenated polycyclic aromatic hydrocarbons, such as petroleum derivatives and coal-tar constituents such as the benzopyrenes and the anthracenes, are those of the CYP1A subfamily. Polyhalogenated aromatic hydrocarbons, such as the halogenated dibenzodioxins, dibenzofurans, and biphenyls, may cause the induction of predominantly the CYP1A subfamily, predominantly the CYP2B subfamily, or mixed CYP1A- and CYP2B-type induction, depending upon the halogen substitution pattern. In contrast, the chlorinated hydrocarbon pesticides, such as DDT, dieldrin, chlordane, and mirex, cause almost exclusively the induction of isoforms of the CYP2B (and to a lesser extent the CYP3A) subfamilies. The commonly employed plasticizing agent di-(2-ethylhexyl)phthalate elicits predominantly induction of the CYP4A subfamily. Those xenobiotics that would be expected to be the most pervasive environmental contaminants are typically those that have also been found to cause the most profound CYP induction responses. Such chemicals are extremely lipophilic and tend to accumulate in animal tissues, especially fatty tissues such as the liver. The hepatic CYP induction response to such potential environmental contaminants is typical of the animals' response to lipophilic xenobiotics in general, and serves as a mechanism by which the excretion of such compounds from the body is facilitated.

Animals↗
PubMed1988

Application of pharmacokinetics to derive biological exposure indexes from threshold limit values.

The importance of incorporating the fundamental concepts of pharmacokinetics into biological monitoring program that involve the collection of various body fluid and tissue specimens is discussed. The application of these principles to establish biological exposures indexes bioequivalent to airborne exposure limits is described. Specific illustrative examples involving acetone, aniline, benzene, carbon tetrachloride, dieldrin, ethylbenzene, hexane, lead, methylene chloride, pentachlorophenol, phenol, styrene, toluene and xylene are presented.

Acetone↗
PubMed2001

Organochlorine pesticides and heavy metals in muscle and ovaries of Gulf coast striped bass (Morone saxatilis) from the Apalachicola River, Florida, USA.

Eight female Gulf coast striped bass (Morone saxatilis) broodfish collected for induced spawning from the Apalachicola River below the Jim Woodruff Lock and Dam were analyzed for organochlorine pesticides (OCs) and metals in muscle and ovarian tissues. Chemical analyses revealed that muscle and ovaries contained detectable amounts of OCs and metals. Concentrations of p,p'-DDE, a derivative of the pesticide DDT, in muscle and ovary (0.54 and 0.65 microg/g, respectively) were significantly higher than alpha-chlordane, dieldrin, and p,p'-DDD. The presence of p,p'-DDE, an antiandrogenic compound, in females suggests that the compound also may be present in male striped bass. Concentrations of Cr, Hg, Mg, and Mn were higher in muscle than in ovarian tissues. Concentrations of Hg have almost doubled in muscle tissues (0.85 microg/g) and tripled in ovaries (0. 15 microg/g) in our samples, compared with the data from 1986 to 1989. Organochlorine pesticides and metal contaminants were present in muscle and ovarian tissues of adult females and may have been retarding development of eggs leading to low hatching rates.

Animals↗
PubMed2004

Levels of organochlorine pesticide residues in marine-, surface-, ground- and drinking waters from the Eastern Cape Province of South Africa.

Persistent organochlorine pesticides (OCPs) such as DDT and its metabolites (DDDs and DDEs). chlordane, hexachlorobenzene (HCB), heptachlor and endosulfan were determined in drinking-, ground-, surface- and marine waters from the Eastern Cape Province of South Africa. Percentage recoveries of the OCPs from spiked river water ranged from 71.03 +/- 8.15% (dieldrin) to 101.25 +/- 2.17% (alpha-BHC). The levels of OCPs ranged from 5.5 ng/L (2,4-DDD) to 160 ng/L (HCB) in the water samples. Some endocrine disrupting OCPs such as DDT, DDE, heptachlor, endosulfan and chlordane were detected.

Chromatography↗
PubMed1965

Penetration of sugars, steroids, amino acids, and other organic compounds into the interior of the squid giant axon.

Squid axons were exposed to solutions of C(14)-labeled compounds. After 60 minutes the axoplasm was extruded and assayed for radioactivity. The following compounds penetrated to about 3 per cent of what would have been expected had there been no barrier to free diffusion and the subsequent attainment of equivalent distribution: mannitol, sucrose, glutamate, glutamine, aspartate, 3,4-dihydroxyphenylalanine, 3,4-dihydroxyphenylethylamine, lambda-aminobutyrate, serotonin, and dehydroepiandrosterone sulfate. All these compounds are water-soluble; in addition, some are ionized over the entire pH range. Partially ionized indoleacetate, acetylsalicylate, and 5,5-diphenylhydantoin penetrated about 40 per cent and unionized, water-insoluble cortisol and dieldrin, 100 per cent. A striking exception to this grouping was glucose, which penetrated about 20 per cent. Studies with specifically labeled glucose indicate participation of the pentose phosphate pathway as a metabolic route in axonal membrane and associated cell wall material, and partial or complete absence of the oxidative system in the axoplasm. Except for glucose, penetration of the substances studied appears to depend largely on the extent of the non-polar, lipophilic character of the compound. Penetration can be markedly increased by pretreatment of the axons with cottonmouth moccasin venom.

Amino Acids↗
PubMed2005

Pesticide use and breast cancer risk among farmers' wives in the agricultural health study.

The authors examined the association between pesticide use and breast cancer incidence among farmers' wives in a large prospective cohort study in Iowa and North Carolina. Participants were 30,454 women with no history of breast cancer prior to cohort enrollment in 1993-1997. Information on pesticide use and other information was obtained by self-administered questionnaire at enrollment from the women and their husbands. Through 2000, 309 incident breast cancer cases were identified via population-based cancer registries. Rate ratios were calculated for individual pesticides using Poisson regression, controlling for confounding factors. Breast cancer standardized incidence ratios were 0.87 (95% confidence interval: 0.74, 1.02) for women who reported ever applying pesticides and 1.05 (95% confidence interval: 0.89, 1.24) for women who reported never applying pesticides. There was some evidence of increased risk associated with use of 2,4,5-trichloro-phenoxypropionic acid (2,4,5-TP) and possibly use of dieldrin, captan, and 2,4,5-trichlorophenoxyacetic acid (2,4,5-TP), but small numbers of cases among those who had personally used the pesticides precluded firm conclusions. The authors found no clear association of breast cancer risk with farm size or washing of clothes worn during pesticide application, but risk was modestly elevated among women whose homes were closest to areas of pesticide application. Further follow-up of this cohort should help clarify the relation between pesticide exposure and breast cancer risk.

Adolescent↗
PubMed1989

Photoactivation of mutagens.

Solutions of several promutagens or of non-genotoxic carcinogens were exposed to sunlight or to artificial sources of UV or fluorescent light, under various experimental conditions. Irradiation resulted in the oxygen-mediated formation of direct-acting mutagenic and DNA-damaging photoproducts in bacteria, with evident structure-activity relationship. Of the aromatic amines tested, 2-aminofluorene and, with lower efficiency, 2-acetylaminofluorene were photoactivated, whereas irradiation of 4-acetylaminofluorene and of the 1- and 2-amino substitutes of anthracene and naphthalene did not produce mutagenic derivatives in Salmonella typhimurium. Of the heterocyclic amines, 2-amino-3-methylimidazo[4,5-f]quinoline and 2-amino-3,4-dimethylimidazo[4,5-f]quinoline were extraordinarily sensitive to activation by sunlight and fluorescent light, which contrasted with the insensitivity of the tryptophan pyrolysis products. Use of optical and interference filters showed that near-UV light is the main component of solar radiation responsible for the formation of highly stable mutagenic derivatives. The mutagenicity of 2-aminofluorene and of the aminoimidazoquinoline compounds, following both metabolic and light activation, was lost in nitroreductase- and O-acetyltransferase-dificient bacteria. Benzo[alpha]pyrene was better activated by 254- than by 365-nm UV light. Sunlight did not affect the lack of mutagenicity of carcinogenic organochlorine pesticides, but exposure to 254-nm UV light selectively resulted in the formation of weak mutagens from dieldrin and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene, but not from 4,4'-dichlorodiphenyltrichloroethane, lacking carbon-carbon double bonds.

DNA Repair↗
PubMed1994

Assessment of chlorinated pesticides and polychlorinated biphenyls in adipose breast tissue using a supercritical fluid extraction method.

A precise and highly reproducible analytical method was developed for the assessment of organochlorinated pesticide and polychlorinated biphenyl residues in adipose tissue (> or = 50 mg). The method can be utilized for epidemiological studies on the significance of these environmental pollutants in the etiology of breast cancer. Supercritical fluid extraction (SFE) with CO2 and modified CO2 (addition of 5% dichloromethane) is employed to remove incurred pesticide residues from adipose tissues that have been surgically removed from breast cancer patients and controls. An alumina sorbent, placed in the extracting vessel together with a specimen, removes the bulk of co-extracted lipids; a subsequent purification of the SFE extracts by column chromatography on alumina removes the remaining traces of lipids that would interfere with the gas chromatographic analysis with electron capture detection. The method was tested by analyzing a Certified Reference Material 430 pork fat with known amounts of pesticide residues that are commonly found in fat or in foods with a high fat content. The recoveries of analytes ranged from 73.4% for endrin to 115% for alpha-, beta- and gamma-hexachlorocyclohexane, hexachlorobenzene and dieldrin, with standard deviations of 4-12% for individual analytes. The analysis of adipose tissue for organochlorinated compounds on the basis of this new method suggested that the pesticide levels were higher in breast cancer patients than in controls. However, the small number of samples analyzed in this study (n = 5, both groups) precludes definitive conclusions. The most abundant compounds in both cases and controls were p, p-DDE (379 +/- 286 and 160 +/- 149 p.p.b.) and PCB (223 +/- 145 and 124 +/- 65.7 p.p.b.), followed by the termiticide chlordane residues oxychlordane and transnonachlor.

Adipose Tissue↗
PubMed2001

Transforming growth factor-beta1-induced Smad signaling, cell-cycle arrest and apoptosis in hepatoma cells.

Transforming growth factor-beta1 (TGFbeta) is involved in the regulation of liver cell proliferation and apoptosis, and escape of hepatoma cells from the growth restraining signals of TGFbeta has been suggested to contribute to tumor development. TGFbeta modulates gene transcription by receptor-mediated activation of Smad proteins which act as transcription factors. TGFbeta-mediated primary signaling responses as well as effects on the cell cycle and apoptosis were investigated in the human hepatoblastoma line HepG2, the rat hepatoma line FTO-2B and the mouse hepatoma line 55.1c. Activation of a Smad (Sma and Mad homolog) response-element-driven luciferase reporter by TGFbeta was very similar in all three cell lines, indicating functionality of the primary TGFbeta signaling pathway. Moreover, TGFbeta-inducible early gene was transiently activated by TGFbeta in all cell lines as shown by RT-PCR. HepG2 cells, however, were completely resistant to TGFbeta-induced growth arrest and apoptosis and 55.1c cells were only slightly susceptible to TGFbeta-induced apoptosis. By contrast, treatment of FTO-2B cells with TGFbeta led to a partial G0/G1 arrest and a strong induction of apoptosis. TGFbeta-induced apoptosis of FTO-2B cells was inhibited by dexamethasone, insulin, phenobarbital and dieldrin. Of these agents, only insulin led to a significant reduction of TGFbeta-stimulated Smad-reporter activity, suggesting that the other compounds interfere with TGFbeta-induced apoptosis downstream of Smad-mediated primary transcriptional responses at a level that may be constitutively altered in apoptosis-resistant hepatoma cell lines.

Apoptosis↗
PubMed1996

An integrated genetic map of the African human malaria vector mosquito, Anopheles gambiae.

We present a genetic map based on microsatellite polymorphisms for the African human malaria vector, Anopheles gambiae. Polymorphisms in laboratory strains were detected for 89% of the tested microsatellite markers. Genotyping was performed for individual mosquitos from 13 backcross families that included 679 progeny. Three linkage groups were identified, corresponding to the three chromosomes. We added 22 new markers to the existing X chromosome map, for a total of 46 microsatellite markers spanning a distance of 48.9 cM. The second chromosome has 57 and the third 28 microsatellite markers spanning a distance of 72.4 and 93.7 cM, respectively. The overall average distance between markers is 1.6 cM (or 1.1, 1.2, and 3.2 cM for the X, second, and third chromosomes, respectively). In addition to the 131 microsatellite markers, the current map also includes a biochemical selectable markers, Dieldrin resistance (Dl), on the second chromosome and five visible markers, pink-eye (p) and white (w) on the X, collarless (c) and lunate (lu) on the second, and red-eye (r) on the third. The cytogenetic locations on the nurse cell polytene chromosomes have been determined for 47 markers, making this map an integrated tool for cytogenetic, genetic, and molecular analysis.

Animals↗
PubMed1992

Chlorinated hydrocarbon content of fetal and maternal body tissues and fluids in full term pregnant women: a comparison of Germany versus Tanzania.

Chlorinated hydrocarbons are distributed worldwide and due to their lipophilic properties and chemical stability they accumulate in the foodchain. The concentrations of 19 different chlorinated hydrocarbons (hexachlorohexane (HCH), DDT and various metabolites and nine different polychlorinated phenyl (PCB) congeners were detected in various body tissues and fluids (maternal and fetal serum, adipose tissue, placenta, amniotic fluid) of full term pregnant women from Germany and Tanzania. Great variation of total toxin burden and toxin distribution within the different body compartments was found. This was in part due to local differences of exposure to some of the chlorinated hydrocarbons. Comparing samples from Germany and Tanzania, typical distribution patterns reflected the specific economic situation of the two countries with a high burden of insecticides (DDT and Dieldrin) in the agricultural country and high levels of constituents of industrial products (hexachlorobenzene (HCB) and PCBs) in Germany. Different chlorinated hydrocarbons seem to show different distribution patterns in body tissues, probably due to their chemical structure, the lipid content of the compartment and the overall toxin burden of the individual. A 10 to 100 fold accumulation of chlorinated hydrocarbons was observed in maternal adipose tissue compared with the other compartments. The concentrations of certain toxins in fetal cord serum and placenta were higher than in maternal serum.

Adipose Tissue↗
PubMedDate not supplied

Determination of chlorinated hydrocarbon pesticides by solid-phase extraction and capillary GC with electron capture detection.

Pesticides and their metabolites are extracted and concentrated from serum using C18 solid-phase extraction cartridges. The internal standard aldrin is added to 4 mL of serum or plasma, treated with 2 mL of methanol, and the resultant supernatant applied to the C18 cartridge. After several washes, pesticides are eluted from the column with isoctane and the eluate quantified with capillary gas chromatography using electron capture detection. Extraction efficiency is from 70 to 75% and the method detection limit ranges from 0.1-0.7 ng/mL depending on the analyte. Precision studies demonstrate that CVs range from 3.5 to 25.2%. Standard curves are linear to at least 7 ng/mL for lindane and chlordane isomers, heptachlor, heptachlor epoxide, oxychlordane, trans-nonachlor, dieldrin, dichlorodiphenyldichloroethylene (p,p'-DDE), dichlorodiphenyldichloroethane (p,p'-DDD), and dichlorodiphenyltrichloroethylene (p,p'-DDT).

Chromatography, Gas↗
PubMed1990

Cyromazine resistance in the house fly (Diptera: Muscidae): genetics and cross-resistance to diflubenzuron.

Larvae of a house fly, Musca domestica L., strain collected in a chicken house near Pittsburg, Tex, after a control failure with the poultry feedthrough insecticide cyromazine showed 6.5-fold resistance to cyromazine and 10-fold resistance to diflubenzuron. Adults of the strain showed high levels of resistance to carbaryl, DDT, and diazinon; moderate resistance to cypermethrin and permethrin; and low resistance to dieldrin. In contrast, no resistance to cyromazine was observed in eight laboratory house fly strains with resistance to four groups of conventional insecticides. When the genetics of cyromazine resistance was investigated in crosses to susceptible strains with visible mutant markers, results indicated cyromazine resistance was incompletely dominant over susceptibility and the resistance gene was on chromosome V. The same or a closely linked gene conferred resistance to diflubenzuron. A strain containing only chromosome V from the original resistant strain was resistant to cyromazine and diflubenzuron, but not to other insecticides except for low level resistance to DDT and carbaryl. Resistance to the latter insecticides appeared to be due to a linked, but distinct, gene. Therefore, resistance to cyromazine and probably diflubenzuron appears to be genetically distinct from other types of insecticide resistance.

Animals↗
PubMed2003

Origin and extent of resistance to fipronil in the German cockroach, Blattella germanica (L.) (Dictyoptera: Blattellidae).

Fipronil, a phenylpyrazole insecticide, was made available in 1999 in bait formulations for use against the German cockroach, Blattella germanica (L.). We have investigated resistance to fipronil in the descendants of cockroaches collected just before, or contemporaneously with, the introduction of fipronil baits. Cockroaches were obtained in two types of settings: homes that either had or had not been serviced by a pest management professional while occupied by their current residents. Thorough inspections by us turned up no evidence that fipronil had been used in any of the homes, and in addition, no residents claimed to have used baits containing fipronil. Resistance to fipronil was detected by topically dosing adult males with the LC99 of fipronil, the value of which was determined in a dose-response assay with males of an insecticide-susceptible strain. Fewer than 99 of 100 males of all field-collected strains died within 72 h of being treated. Moreover, substantial numbers of males survived doses three and 10-fold greater than the LC99. Regression analysis showed that 67% of the variation in the percentage of males that died after being treated with fipronil was explained by a linear relationship with the percentage that died after being treated with dieldrin. Therefore, it appears that resistance to fipronil in German cockroaches--whose ancestors had never been exposed to it--is attributable to enduring resistance to the cyclodienes, which were formerly used for cockroach control and have a similar mode of action as fipronil. Lastly, we found that insects resistant to topically administered fipronil were likewise resistant, and to a similar degree, to ingested fipronil.

Animals↗
PubMedDate not supplied

Genetic traits of the mosquito Anopheles gambiae: red stripe, frizzled, and homochromy1.

The expression, inheritance, and linkage relationships of three genetic traits were studied in the malaria vector Anopheles gambiae. Red stripe (Rs) is a common phenotypic polymorphism in numerous A. gambiae populations, whereas frizzled (f) and homochromy1 (hom1) were isolated from (60)Co-irradiated mosquitoes. Red stripe appears as a diffuse stripe of pigment on the dorsum of larvae and pupae and is variable in expressivity and penetrance. Our data demonstrate that Red stripe results from a heterozygous collarless genotype (i.e., c+ c, chromosome 2) and is essentially sex-limited to females. frizzled is a sex-linked recessive semi-lethal identified by deformed lateral larval setae; its lethality manifests as low rates of adult emergence and brief adult survival. frizzled is located on the X chromosome between pink eye and Mosaic, 3 cM from Mosaic and approximately 12 cM from pink eye. Finally, the mutation homochromy1 (hom1) is on chromosome 2 and causes a recessive phenotype that prevents normal darkening of larvae when reared in a black container. Unlike mutants with this characteristic described thus far, the eye color of hom1 mutants is normal. We determined that hom1 is located between Dieldrin resistance and collarless, approximately 3 cM from the latter. We discuss the possibility of differences in male and female recombination values and the range of values that have been observed in test crosses for chromosome 2 markers.

Alleles↗
PubMedDate not supplied

Molecular mapping of insecticide resistance genes in the yellow fever mosquito (Aedes aegypti).

Several loci conferring insecticide resistance in the yellow fever mosquito (Aedes aegypti) have previously been mapped by simple recombinational mapping. Here we describe correlation of these resistance phenotypes with molecular gene probes for insecticide target sites by RFLP mapping. The para sodium channel gene homologue and the GABA receptor gene Resistance to dieldrin map to the same genome regions as the DDT/pyrethroid and cyclodiene resistance loci, respectively. Although the acetylcholinesterase (target site of organophosphorus and carbamate insecticides) gene Ace does not map to any known resistance locus, it maps very close to the sex-determining locus. We discuss the possibilities that, if identified, Ace-mediated resistance in A. aegypti will be sex linked or that, as suggested for anopheline mosquitoes, two independent Ace loci may exist, one of which is autosomal. These results support the importance of target site insensitivity as an insecticide resistance mechanism in mosquitoes.

Aedes↗