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PubMed1994

Changes in gap-junction permeability, phosphorylation, and number mediated by phorbol ester and non-phorbol-ester tumor promoters in rat liver epithelial cells.

The effects of three tumor promoters on gap-junction permeability; connexin 43 and 26 mRNA levels, protein levels, and phosphorylation; and the numbers of gap-junctional membrane plaques were studied in the rat liver epithelial cell line WB-F344 to determine whether changes in these parameters correlated with the inhibition of gap-junction function. 12-O-tetradecanoylphorbol-13-acetate (TPA; 10 ng/mL), dieldrin (10 micrograms/mL), and heptachlor epoxide (10 micrograms/mL) inhibited gap-junctional intercellular communication (GJIC) assayed by fluorescent dye transfer by 80-90% after a 5-min exposure and by more than 90% within 1 h. Decreases in steady-state connexin 43 mRNA levels were detected by northern blot analysis within 1 h and paralleled changes in steady-state beta-actin mRNA, but these changes did not occur rapidly enough to account for the rapid loss of gap-junction function. A substantial loss in the number of connexin 43 immunostained gap-junctional membrane plaques was detected after a 15-min exposure to all three promoters, but little change had occurred at 5 min. Western blot analyses using connexin 43-specific antibodies showed changes in the degree of connexin 43 phosphorylation for all three tumor promoters. TPA induced the appearance of a fourth connexin 43-immunoreactive band (P3) and a concomitant decrease in the relative intensity of the unphosphorylated (P0) band within 5 min of treatment. P3, in addition to bands P1 and P2, disappeared after treatment with alkaline phosphatase. In contrast, dieldrin and heptachlor expoxide induced loss of P2 with a concomitant increase in the relative staining intensity of P0 within 1 h of exposure, but no changes were seen after 5 min. Connexin 43 phosphorylation levels recovered in parallel with the recovery of GJIC for all three tumor promoters. Connexin 26 mRNA levels showed little change after a 1-h exposure to three promoters, but reductions in connexin 26 immunofluorescent staining were observed. These results suggest that (i) TPA-induced hyperphosphorylation of connexin 43 occurred fast enough to account for inhibition of GJIC, (ii) dieldrin and heptachlor expoxide modulated connexin phosphorylation in a manner different from TPA by promoting hypophosphorylation of connexin 43, (iii) redistribution of plasma membrane gap-junctional plaques after treatment with phorbol ester and non-phorbol-ester tumor promoters occurred subsequent to changes in gap-junction permeability, and (iv) changes in connexin mRNA levels could not account for the losses in fluorescent dye coupling induced by these promoters.

Animals↗
PubMed1977

Hepatic vein thrombosis in mice ingesting chlorinated hydrocarbons.

Hepatic vein thrombosis, as well as hepatocellular carcinomas, was induced in inbred C3H male and female mice ingesting 10 ppm of dieldrin, aldrin, heptachlor, or heptachlor epoxide in the diet. Thrombosis was present in 5% of mice ingesting dieldrin or aldrin and in 10.5% of mice ingesting heptachlor or heptachlor epoxide. Occlusion of the hepatic vein often resulted in infarcts of the liver. Females ingesting heptachlor or heptachlor epoxide were slightly more susceptible than males. There was no difference between male and female mice ingesting dieldrin or aldrin. Hepatic vein thrombosis did not appear to be related to the development of carcinoma of the liver because it was present in livers without carcinomas as well. Thrombosis was usually seen only in the liver but also rarely was present in the atria of the heart.

Aldrin↗
PubMed1980

The effect of hepatic microsomal monooxygenase induction on the metabolism and toxicity of the organophosphorus insecticide chlorfenvinphos.

The induction of rat liver microsomal monooxygenase by pretreatment of rats with dieldrin affords a 10-fold protection against the acute toxic effects of the organophosphorus insecticide, chlorfenvinphos. Metabolism studies were carried out to confirm that the protection was due to an enhanced rate of detoxification (via oxidative deethylation). At low doses of chlorfenvinphos (2.5 mg . kg-1), dieldrin pretreatment caused minimal changes in the metabolic profiles. However, at a higher dose (13.2 mg . kg-1), giving clinical signs of intoxication in the control animals, the dieldrin pretreated rats produced 5 times more deethylchlorofenvinphos than did the control animals. The results support the conclusion that the effect of enzyme induction on the metabolism of substrates of that enzyme are dose-dependent. Alterations in metabolism, therefore, are not an automatic consequence of enzyme induction.

Animals↗
PubMed1989

Clastogenicity evaluation of seven chemicals commonly found at hazardous industrial waste sites.

7 chemicals commonly found at the industrial waste sites were tested with the Tradescantia-Micronucleus (Trad-MCN) assay to evaluate their clastogenic potential. Chemicals selected from the US EPA Superfund Priority 1 list were: aldrin, arsenic trioxide, 1,2-benz[a, h]anthracene, dieldrin, heptachlor, lead tetraacetate and tetrachloroethylene. Results of repeated tests for clastogenicity yielded the minimum effective dose (MED) for clastogenicity of 0.44 ppm for lead tetraacetate, 1.88 ppm for heptaclor, 3.81 ppm for dieldrin and arsenic trioxide and 1,2-benz[a, h]anthracene yielded positive responses at the MED of 3.96 ppm and 12.50 ppm respectively. Aldrin and tetrachloroethylene were considered to be immiscible with water, and the tests yielded negative responses. Tetrachloroethylene in gaseous state was also used to treat the flower buds. Results of tetrachloroethylene vapor phase treatment yielded a positive response at the MED of 30 ppm/min after a 2-h exposure. 5 chemicals determined to be clastogens by this test were ranked according to their MED in the descending order of potency as follows: lead tetraacetate, heptachlor, dieldrin, arsenic trioxide and 1,2-benz[a, h]anthracene. Results of this study indicate that the Trad-MCN bioassay could be effectively utilized for assessing the potential clastogenicity of the chemicals commonly found at the industrial hazardous waste sites.

Aldrin↗
PubMed1987

Strain and species effects on the inhibition of hepatocyte intercellular communication by liver tumor promoters.

The effect of the liver tumor promoters phenobarbital (PB), 1,1-bis(4-chlorophenyl)-2,2,2-trichlorethane (DDT), and dieldrin on gap junction-mediated intercellular communication between primary cultured hepatocytes from male mice (B6C3F1), C3H, C57BL, and Balb/c strains) and male F344 rats was determined. Intercellular communication was detected autoradiographically as the passage and incorporation of [5-3H]uridine nucleotides from prelabelled donor hepatocytes to donor-contacting recipient hepatocytes. At non-toxic concentrations, PB (20-500 micrograms/ml) inhibited intercellular communication between B6C3F1, C3H, and Balb/c mouse hepatocytes and F344 rat hepatocytes, but not between C57BL mouse hepatocytes. DDT (1-10 micrograms/ml) inhibited intercellular communication between hepatocytes from all 4 strains of mice and the F344 rat. Dieldrin (1-10 micrograms/ml) inhibited intercellular communication between hepatocytes from the 4 strains of mice but not between rat hepatocytes. These findings showed a good correlation with the in vivo liver tumor promoting/hepatocarcinogenic actions of PB, DDT and dieldrin in the 4 mouse strains and the F344 rat strain.

Animals↗
PubMed1996

Wild-type and insecticide-resistant homo-oligomeric GABA receptors of Drosophila melanogaster stably expressed in a Drosophila cell line.

RDL is an ionotropic GABA receptor subunit, a product of the Rdl gene, originally identified in the Maryland strain of Drosophila melanogaster. Here, we report the generation of a Drosophila melanogaster cell line (S2-RDLA302S) stably expressing a mutated, dieldrin-resistant (A302S) form of RDL. The properties of this dieldrin-resistant, homo-oligomeric receptor have been compared with those of the stably expressed, wild-type form (S2-RDL). Using these stable lines, a striking reduction in sensitivity to both picrotoxinin and dieldrin was observed for responses to GABA of S2-RDLA302S compared to S2-RDL. To determine if these stable insect cell lines generate results similar to those obtained by transient expression in Xenopus laevis oocytes, we have examined the actions of two widely used convulsants, EBOB and TBPS, and a recently developed convulsant BIDN, on RDL-mediated GABA responses in the two expression systems. In both oocytes and S2 cells, the three convulsants suppressed the amplitude of responses to GABA. Thus, in accord with earlier work on agonist and allosteric sites, the S2-RDL cell line is found to yield similar pharmacological results to those obtained in transient expression studies. Stable cell lines are now available expressing susceptible and resistant forms of an ionotropic receptor by GABAergic insecticides.

Animals↗
PubMed2001

Prevention of organochlorine-induced inhibition of gap junctional communication by chaetoglobosin K in astrocytes.

Innumerable toxic substances present in the environment inhibit gap junctions, intercellular membrane channels that play fundamental roles in coordinated function of cells and tissues. Included are persistent organochlorine compounds, which pose health risks to humans and animals owing to their widespread use, bioaccumulation, and ability to inhibit gap junction channel-mediated intercellular communication in liver, lung, skin, heart, and brain cells. In this study, the organochlorine xenobiotics dieldrin and endosulfan, at micromolar concentrations, were found to inhibit gap junction-mediated intercellular communication and induce hypophosphorylation of connexin 43 in cultured rat astrocytes, the predominant cell type in the brain coupled through gap junctions. This inhibition of gap junctional communication was substantially reduced by preincubation with chaetoglobosin K (ChK), a bioactive natural produce previously shown to have ras tumor suppressor activity. Chaetoglobosin K also prevented dieldrin and endosulfan-induced hypophosphorylation of connexin 43 and prevented dieldrin-induced connexin 43 plaque dissolution in both astrocytes and cultured liver epithelial cells. The results suggest that stabilization of the native, phosphorylated form of connexin 43 by ChK may contribute to its ability to prevent organochlorine-induced inhibition of gap junction-mediated communication and dissolution of gap junction plaques within the plasma membrane.

Animals↗
PubMed1989

Review of tsetse control measures taken in the Lambwe Valley in 1980-1984.

During an outbreak of Rhodesian sleeping sickness in the Lambwe Valley in 1980 initial tsetse control measures consisted of applications of dieldrin to the periphery of the Ruma National Park. This activity had a marked effect on the prevalence of sleeping sickness. Concern about the use of dieldrin caused the cessation of this programme and justified an aerial spray programme using endosulfan. Although the Lambwe Valley did not appear to be a good candidate for aerial spray, the endosulfan had a marked effect on tsetse fly levels and on the prevalence of sleeping sickness. Sleeping sickness cases were detected in decreasing numbers for eight months following the endosulfan programme, but the subsequent five months yielded no cases of sleeping sickness in the area. Some flies persisted, however, and they had regained high levels in about a year. As the prevalence of sleeping sickness increased another aerial spray programme was initiated in 1983, using pyrethrum as insecticide. The pyrethrum aerial spray programme did not make significant reductions in the Glossina pallidipes population or in the prevalence of sleeping sickness. A subsequent ground control programme using insecticides (dieldrin and cypermethrin) and bush clearing, conducted primarily within the National Park, has subsequently limited the prevalence of sleeping sickness to low levels.

Aerosols↗
PubMed2005

Bioaccumulation studies of organochlorinated pesticides in tissues of Cyprinus carpio.

Freshwater fish Cyprinus carpio was selected for the study of bioaccumulation of organochlorinated pesticides in tissues like gills, muscle, intestine, kidney, and liver in a continuous fed system. The pesticides used were Aldrin, Dieldrin, BHC, and DDT. The bioaccumulation of Dieldrin was maximum of 85.0 microg g(-1) wet weight in liver tissue while minimum of 7.30 microg g(-1) wet weight for DDT at 30 days exposure time. Bioconcentration factor (BCF) has followed the same trend in liver tissue for Dieldrin and DDT. The rate of bioaccumulation was found to be maximum of 4.3879 microg g(-1) wet weight in liver tissue and minimum of 0.0021 microg g(-1) wet weight in gill tissue for 30 days exposure. As evidenced by the increasing values of BCF, pesticide uptake also showed increased trend with the increase in exposure time. A high correlation coefficient ranging between 0.7247 and 0.9616 between the pesticide concentration and exposure time was observed. Based on actual BCF values, log Kow were calculated and the values are well within the reported values of 6.5 indicating efficient relationship between BCF and log Kow because beyond the 6.5 the bioconcentration levels off.

Aldrin↗
PubMed1990

Testing Anopheles albimanus for genetic linkage of insecticide resistance genes by combining insecticide bioassay and biochemical methods.

A microtitre-plate assay which distinguishes propoxur-resistant from susceptibles Anopheles albimanus Weidemann was used to test for linkage between the genes for propoxur- and dieldrin-resistance. The adult progeny of a backcross between a doubly-resistant colony and a fully susceptible colony were exposed in conventional test kits to the standard discriminating dose of dieldrin, and kept in the insectary overnight. Both live and dead insects were then assayed individually for propoxur-resistance. The results showed that heterozygotes for propoxur-resistance could be reliably distinguished from susceptibles whether or not they had been killed up to 24 h previously by dieldrin treatment. In this way all the backcross progeny could be scored at both resistance loci, and all four genotypic classes identified. Resistant and susceptible alleles at the two loci were inherited independently, demonstrating the absence of linkage. The usual method of testing for linkage between resistance genes is inefficient and open to bias, because insects have to be exposed to each insecticide in turn, and only half of them can be scored at both loci. The method shown here avoids these drawbacks.

Alleles↗
PubMed1975

Comparative ability of hybrid and homozygous resistant larvae of Lucilia cuprina to cause strikes under experimental conditions.

The intervals between the jetting of sheep with dieldrin or BHC, and the inducement of flystrike by implants of hybrid and homozygous BHC/dieldrin resistant larvae of Lucilia cuprina, were compared. Flystrikes soon established with homozygous resistant larvae, but considerable protection was afforded against hybrid larvae, the interval being longer with BHC than with dieldrin. Dieldrin was shown to have a residual effect on rr larvae in a mixed population 9 weeks after jetting. It is suggested that wide adoption of mulesing and mid-season's crutching would favour reversion to susceptibility in the blowfly and thus extend the field life of insecticides to which resistance has emerged.

Animals↗
PubMed1997

In vitro synergistic interaction of alligator and human estrogen receptors with combinations of environmental chemicals.

The effect of mixtures of environmental chemicals with hormonal activity has not been well studied. To investigate this phenomenon, the estrogen receptor (ER) from the American alligator (aER) or human (hER) was incubated with [3H]17beta-estradiol in the presence of selected environmental chemicals individually or in combination. The environmental chemicals included the insecticide chlordane, which has no estrogenic activity, and the pesticides dieldrin and toxaphene, which have very weak estrogenic activity. Chlordane, dieldrin, and toxaphene individually demonstrated no appreciable displacement of [3H]17beta-estradiol from aER and hER at the concentration tested. A combination of these chemicals inhibited the binding of [3H]17beta-estradiol by 20 to 40%. Alachlor, a chemical recently discovered to have weak estrogenic activity, also displaced [3H]17beta-estradiol more effectively in combination with dieldrin than alone. These results indicate that combinations of some environmental chemicals inhibit [3H]17beta-estradiol binding in a synergistic manner. This suggests that the ER may contain more than one site for binding environmental chemicals. The possibility that the ER binds multiple environmental chemicals adds another level of complexity to the interaction between the environment and the endocrine system.

Acetamides↗
PubMed1978

Effect of chlorinated hydrocarbons on reproductive performance of adult White Leghorn male chickens.

Two experiments of 20 and 40 weeks duration were conducted to determine the effects of feeding dieldrin or PCB (Aroclor 1254) on the reproductive performance of adult White Leghorn males. Dieldrin at the levels used (0, 25, and 50 ppm) produced no significant changes in semen volume, semen concentration, fertility, and hatchability of fertile eggs. Mortality increased with increased levels of dieldrin and appeared related to duration of exposure to the pesticide. A significant reduction (P less than .05) in feed consumption was observed at the 25 ppm level. No significant differences in body weights were observed except shortly before death when marked reductions in both feed consumption and body weight were noted. PCB at the levels used (0, 10, 20, and 40 ppm) produced no differences in fertiluty, hatchability of fertile eggs, body weights, feed consumption, or mortality. However, over a period of 40 weeks, PCB significantly (P less than .05) reduced semen volume, semen concentrations, and testes weights,

Animal Feed↗
PubMed1986

Residues of chlorinated hydrocarbons in tissues of raptors in Florida.

Dead or moribund raptors (n = 75) representing 11 species were collected between 1971 and 1981 from various locations in Florida. Samples of bran, muscle, liver and adipose tissue were analyzed for DDT, DDE, DDD, dieldrin, and PCB's. Detectable concentrations of DDT or its metabolites were found in 100% of all samples of muscle and liver, and 77% all samples of brain. Dieldrin was determined to be present in 91%, 93%, 87% and 78% of all samples of brain, muscle, liver and adipose tissue, respectively. Lethal or hazardous concentrations of dieldrin were found in brain samples from three birds, but DDT and PCB's were present at sublethal concentrations. When species were grouped according to their dietary habits, it was not possible to identify any trends in pesticide concentrations.

Adipose Tissue↗
PubMed1978

Residues of organochlorine insecticides and polychlorinated biphenyls in fish from Lakes Huron and Superior, Canada--1968-76.

Five species of fish from Lake Superior and 12 species from Lake Huron were analyzed for organochlorine pesticides and polychlorinated biphenyls (PCBs) between 1968 and 1975. Mean residues of sigma DDT peaked at 1.72 ppm and 7.60 ppm in lake trout (Salvelinus namaycush) from Lakes Superior and Huron, respectively. By 1975, the mean level of sigma DDT had decreased in lake trout and was highest in bloaters (Coregonus hoi) from both lakes: 1.06 ppm and 1.87 ppm, respectively. Dieldrin levels in fish from Lake Superior changed little over the same period. However, in 1969-70, dieldrin levels in fish from Lake Huron exceeded the 0.3 ppm tolerance level set by Health and Welfare Canada or the Food and Drug Administration, U.S. Department of Health, Education, and Welfare in 5 percent of lake whitefish (Coregonus clupeaformis) and 10 percent of bloaters. By 1975, 50 percent of bloaters caught in Georgian Bay and North Channel had dieldrin levels above 0.3 ppm. PCB residues declined in lake trout and lake whitefish caught in Lake Superior between 1971 and 1975, but increased slightly in bloaters and white sucker (Catostomus commersoni). Mean PCB residues in bloaters caught in Lake Huron in 1969-71 and 1975-76, and splake (Salvelinus fontinalis and S. namaycush) and cisco (Coregonus artedii) caught in 1975 exceeded the 2 ppm tolerance level.

Animals↗
PubMed1959

Insecticide resistance in Anopheles sacharovi.

A series of observations is presented on the susceptibility or resistance to insecticides of Anopheles sacharovi in Greece, Iran, Italy, Romania and Turkey. High physiological resistance to DDT was observed in the Tarsus area of southern Turkey. In Greece very marked physiological resistance to dieldrin was found in all the areas examined and was associated, at least in the Peloponnese, with similar resistance to DDT, affecting, however, only a part of the sacharovi population. In Italy and Romania, after 10 years' use of DDT, sacharovi is still susceptible to it; long use of BHC in Romania has not resulted in the development of resistance to dieldrin or to BHC. Further investigation of the situation in Iran is considered necessary.The fact that the use of DDT in Greece, after the development of resistance to this insecticide in 1951, has not resulted in the formation of a highly resistant mosquito population is considered to be due to the irritant effect of the DDT on susceptible mosquitos, causing them to leave sprayed surfaces before they have picked up a lethal dose.The information to date points to the existence in A. sacharovi of two independent mechanisms of physiological resistance-one to DDT and another to dieldrin and BHC-which may or may not be present together.

Animals↗
PubMed1975

Residues of organochlorine pesticides and polychlorinated biphenyls and autopsy data for bald eagles, 1971-72.

Thirty-seven bald eagles found sick or dead in 18 States during 1971-72 were analyzed for organochlorine pesticides and polychlorinated biphenyls (PCB's). DDE and PCB's were detected in all bald eagle carcasses; 30 carcasses contained DDD and 28 contained dieldrin. Four eagles contained possibly lethal levels of dieldrin and nine eagles had been poisoned by thallium. Autopsies revealed that illegal shooting was the most common cause of mortality. Since 1964 when data were first collected, 8 of the 17 eagles obtained from Maryland, Virginia, South Carolina, and Florida possibly died from dieldrin poisoning; all four specimens from Maryland and Virginia were from the Chesapeake Bay Tidewater area.

Animals↗
PubMed1978

Chlorinated hydrocarbon pesticide residues in Pacific oysters (Crassostrea gigas) from Tasmania, Australia--1973.

Pacific oysters (Crassostrea gigas Thunberg) from 19 sites in Tasmania were surveyed for pesticide residues. All samples were analyzed for dieldrin and DDT, and five samples were analyzed for hexachlorobenzene (HCB) and lindane. Only DDT was found in all samples. Dieldrin levels were high in oysters from the Tamar River, but were highest (0.39 mg/kg wet weight) in samples from Ruffin's Bay. In contrast, other residue levels were low. Distribution of pesticides in Tamar River samples differed: dieldrin could be correlated with industrial uses upstream and DDT could be correlated with low-level widespread agricultural use.

Animals↗