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Overview of human exposure to dieldrin residues in the environment and current trends of residue levels in tissue.

An overview of available literature indicates that dieldrin residues are still found routinely in soil, air, water, and food, despite the 1974 U.S. Environmental Protection Agency ban on the use of aldrin and dieldrin. Dieldrin residue levels in environmental substrates, which are indicative of aldrin or dieldrin use, have decreased significantly since the mid-1960s, the peak usage years. However, human tissue studies do not show a corresponding decline in dieldrin residue levels. Thirteen studies, conducted between 1963 and 1976, show that average dieldrin levels in human adipose tissue and human milk fat remain between 0.160 ppm and 0.220 ppm. Other studies suggest that an equilibrium exists in the distribution of dieldrin among various tissues in humans, including blood, fat, brain, and liver. This relationship indicates that the concentration of dieldrin in any tissue may be used as an index of total body burden. Thus it appears that the concentration of dieldrin in the human body has reached a constant level at which the amount ingested and absorbed equals the amount metabolized and excreted. The mechanism of the stable concentrations is unknown, as are the possible health effects of chronic, low-level exposure to dieldrin.

Adipose Tissue

Teratogenesis, toxicity, and bioconcentration in frogs exposed to dieldrin.

Teratogenesis, acute and chronic toxicity, growth and bioconcentration were investigated in various life stages (embryos, tadpoles, juveniles, adults) of the frogs Xenopus laevis (African clawed frog), Rana catesbeiana (bullfrog) and Rana pipiens (leopard frog) exposed to aqueous dieldrin in static-renewal and flow-through systems in a study on the development of wildlife-based water quality criteria. R. catesbeiana was the most sensitive tadpole in acute tests; X. laevis was the most sensitive in embryo-larval and chronic tadpole tests. Tadpole 96-h LC50s ranged from 40.4 to 49.5 micrograms/L dieldrin for X. laevis, from 8.7 to 30.3 micrograms/L for R. catesbeiana and was 71.3 micrograms/L for R. pipiens. The 24-day LC50 for X. laevis tadpoles was 5.5 micrograms/L dieldrin; the 28-day LC50 for R. pipiens tadpoles was 8.3 micrograms/L. Adult R. pipiens had a 28-day LC50 of 53.4 micrograms/L dieldrin. Gross spinal deformities in embryo-larval tests were observed at dieldrin concentrations as low as 1.3 micrograms/L after 10-days exposure to X. laevis and at 25.4 micrograms/L for a 21-day exposure to R. catesbeiana. Mean X. laevis 14 to 21-day LOAEL (Lowest Observed Adverse Effect Level) and NOAEL (No Observed Adverse Effect Level) values for embryo-larval tests (25.5 and 11.0 micrograms/L dieldrin, respectively) were virtually the same as the 21-day single test values obtained for R. catesbeiana (25.1 and 11.0 micrograms/L dieldrin). Mean 14 to 24-day X. laevis LOAEL and NOAEL values for tadpole chronic tests (1.6 and less than 1.4 micrograms/L dieldrin, respectively) were lower than the 28-day single test values obtained for R. pipiens (4.1 and 1.9 micrograms/L, respectively). Tissue dieldrin levels at the LC50, LOAEL and NOAEL in the tadpole acute tests were fairly similar between X. laevis (11, 24 and 7 micrograms/g, respectively) and R. catesbeiana (means of 8.6, 12.0 and 1.2 micrograms/g, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals

Dual action of the cyclodiene insecticide dieldrin on the gamma-aminobutyric acid receptor-chloride channel complex of rat dorsal root ganglion neurons.

The gamma-aminobutyric acidA (GABAA) receptor-chloride channel complex is known to be the target site of dieldrin, a cyclodiene insecticide, and lindane. In order to elucidate the mechanisms of dieldrin interaction with the GABA system, whole-cell patch clamp experiments were performed with rat dorsal root ganglion neurons in primary culture. When co-applied with GABA, dieldrin exerted a dual effect on the GABA-induced chloride current. The chloride current induced by 10 microM GABA was greatly enhanced by the first 20-sec co-application with 1 microM dieldrin, but the enhancement subsided during repeated co-applications, and the current was eventually suppressed below the control level. No recovery occurred after a prolonged washing with dieldrin-free solution. Desensitization of the chloride current was accelerated by dieldrin. However, when the period of co-application was limited to 2 sec, which was short enought to avoid desensitization, no suppression of current was observed during repeated co-applications and recovery occurred after washing. The desensitization and suppression occurred with an EC50 of 92 nM, whereas the enhancement required a higher EC50 at 754 nM. The GABA-induced chloride current comprised two components, one with a high sensitivity to dieldrin suppression with an EC50 of 5 nM and the other with a lower sensitivity with an EC50 of 92 nM. Dieldrin exerted its inhibitory effect on the GABA-induced current regardless of the presence or absence of pentobarbital and chlordiazepoxide. However, its effect was attenuated by the presence of picrotoxin. Furthermore, dieldrin suppressed the GABA-induced chloride current in a noncompetitive manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals

Subchronic effects of dieldrin and phenobarbital on hepatic DNA synthesis in mice and rats.

Dieldrin, an organochlorine pesticide, has been shown to be hepatocarcinogenic in mice but not rats. Phenobarbital, in contrast, induces hepatic tumors in both mice and rats. Previous studies have shown that acute dietary exposure of rats or mice to either dieldrin or phenobarbital produces several liver changes, including centrilobular hypertrophy, induction of hepatic cytochrome P450, and increased liver weight. The present study examined the subchronic effect of dieldrin (0.1, 1.0, 3.0, 10.0 mg dieldrin/kg diet) and phenobarbital (10, 50, 100, 500 mg phenobarbital/kg diet) on the induction of hepatic DNA synthesis and hepatocyte lethality in male B6C3F1 mice and male F344 rats. Eight-week-old animals were treated as above and evaluated for hepatic DNA synthesis after 7, 14, 21, 28, and 90 days of continual treatment to dieldrin or phenobarbital. Maximal induction of hepatic DNA synthesis in mice was seen at the 14-, 21-, and 28-day sampling times. In rats, no significant increase in hepatic DNA synthesis or hepatocyte lethality was observed at any dose of dieldrin investigated. Phenobarbital produced a significant increase in hepatic DNA synthesis in both rat and mouse liver following 7 days of treatment. The induction of DNA synthesis in rat liver was transient, with the labeling index returning to control levels by 14 days of treatment. In contrast, mice treated with phenobarbital showed a significant increase in hepatic DNA synthesis throughout the treatment. In both mice and rats, dieldrin and phenobarbital induced hepatic DNA synthesis selectively in the centrilobular region of the hepatic lobule. The lack of an increase in serum enzymes indicative of hepatic damage and the absence of liver histopathology in mice or rats fed dieldrin or phenobarbital indicate that the induction of DNA synthesis was not mediated by a cytolethal, compensatory hyperplastic response, suggesting a mitogenic mechanism. Therefore, the species-specific induction of hepatic DNA synthesis by either dieldrin or phenobarbital correlated with the previously observed species-specific induction of hepatic cancer by these two compounds.

Analysis of Variance

Selective effects of dieldrin on the GABAA receptor-channel subunits expressed in human embryonic kidney cells.

We have recently demonstrated that the cyclodiene insecticide dieldrin modulates the kinetics of the GABAA receptor-chloride channel complex of rat dorsal root ganglion neurons in a complex manner, causing both stimulatory and inhibitory effects. We now report that the differential effects of dieldrin on the GABA-induced chloride current of human embryonic kidney cells expressing three different combinations of alpha, beta and gamma subunits. The EC50 values for GABA induction of current were estimated to be 9.8 microM for the alpha 1 beta 2 gamma 2s combination, 2.0 microM for the alpha 1 beta 2 combination and 3.0 microM for the alpha 6 beta 2 gamma 2s combination. When co-applied with GABA, dieldrin exerted a dual effect, enhancement and suppression, on the GABA-induced chloride currents in the alpha 1 beta 2 gamma 2s and alpha 6 beta 2 gamma 2s combinations. However, only suppression was observed in the alpha 1 beta 2 combination, indicating that the gamma subunit is necessary for dieldrin's enhancing effect. Dieldrin was more efficacious in enhancing the current in the alpha 6 beta 2 gamma 2s combination than in the alpha 1 beta 2 gamma 2s combination, indicating some specific role of alpha subunits in the dieldrin enhancement of current. Dieldrin suppressed the GABA-induced current in a non-competitive manner, with an EC50 value of 2.1 microM for alpha 1 beta 2 gamma 2s, 2.8 microM for alpha 1 beta 2 and 1.0 microM for alpha 6 beta 2 gamma 2s combination. These results indicated that dieldrin suppression did not require specific subunit combinations among the three tested.

Cell Line

Increased susceptibility to mouse hepatitis virus 3 of peritoneal macrophages exposed to dieldrin.

Interaction of a single dose (36 mg/kg body wt) of the organochlorine pesticide dieldrin with mouse peritoneal macrophages was examined in C57Bl/6, (C57Bl/6 X A/J)F1, and A/J strains of different genetic resistance to mouse hepatitis virus 3 (MHV3) infection. In vivo studies showed increased susceptibility to MHV3 acute disease of C57Bl/6 and (C57Bl/6 X A/J)F1 animals challenged with the pesticide. Significant decrease of mean time of death in dieldrin-exposed, MHV3-infected susceptible C57Bl/6 mice was observed similarly upon po or ip administration of a single, sublethal dose of dieldrin. In addition, decrease of humoral response to the virus was quantified by determination of anti-MHV3 IgG antibodies in spleen cell supernatant fractions and in blood sera of dieldrin-exposed C57Bl/6 mice. A single dose of dieldrin did not alter the in vivo resistance of A/J animals to acute MHV3 disease. The resistant A/J mice, however, showed increased mortality upon two subsequent exposures to dieldrin followed by infection with high lethal doses of MHV3. Phagocytic activity, cell adherence capacity, and attachment and uptake of 3H-radiolabeled MHV3 by C57Bl/6 peritoneal macrophages were determined by in vitro studies. These affector activities of peritoneal macrophages were slightly decreased or unchanged in cells originating from animals exposed to the pesticide. However, the intrinsic activity of MHV3 restriction appeared to be affected in macrophages derived from dieldrin-treated animals: (i) peritoneal C57Bl/6 macrophages collected from the early phase of acute MHV3 disease contained increased MHV3 antigen and (ii) increased cytolysis was observed after in vitro MHV3 infection of macrophages originating from dieldrin-exposed C57Bl/6 mice.

Animals

Effect of dieldrin and calcium on the performance of adult Japanese quail (Coturnix coturnix japonica).

Two experiments were conducted to determine the effects of dieldrin and calcium on reproductive performance of quail. At 25% egg production the quail received diets containing 0,10 or 25 p.p.m. of dieldrin for 6, 28-day periods in experiment 1 and 0, 5, or 25 p.p.m. of dieldrin for 4, 28-day periods in experiment 2. Pesticide treatments were employed with diets containing 0.5% and 3.0% calcium. The results show that egg shell thickness, cracked eggs, egg production, feed consumption, egg weights, fertility, hatchability and body weights were not affected by dieldrin treatments. However, egg shell thickness, cracked eggs, egg production and hatchability were adversely affected by the lower calcium level. Female body weights were consistently heavier for the low calcium diet. Mortality increased in the presence of 10 and especially 25 p.p.m. of dieldrin. Livability of chicks from hens receiving rations with 10 and 25 p.p.m. of dieldrin was significantly lower than those fed no dieldrin. In summary, dieldrin was without effect on egg shell quality or other reproductive factors but did exert a detrimental effect on adult mortality and livability of progeny.

Animals

Dieldrin-induced changes in isoenzyme composition in the livers of CF-1 mice.

The isoenzyme composition of lactic dehydrogenase (LDH), pyruvate kinase (PK) and alanine-aminotransferase was determined in the livers of CF-1 mice exposed to 0, 5 or 10 ppm dieldrin in the diet, over a period of 14 months. This study was carried out to evaluate whether the liver tumor promoter dieldrin advances the biological age of CF-1 mouse liver. Oral dieldrin exposure induced a dose-dependent shift towards the fetal types of lactic dehydrogenase and pyruvate kinase, within 1.5 months of initiation of treatment. After the initial shift, no additional dieldrin-dependent changes were found in CF-1 mouse liver throughout the experimental observation period. Thus, the initial shifts in isoenzyme composition of LDH and PK appear to reflect the adaptation of the liver to increased functional demands imposed by dieldrin treatment. The expression of the cytoplasmic A-alanine-aminotransferase isoenzyme decreased with age in untreated control mice. Dieldrin treatment enhanced this process in a dose-dependent manner. These data suggest that dieldrin treatment can accelerate age-dependent changes in gene expression.

Aging

Comparative behavior of dieldrin and carbofuran in the field.

To measure the amounts of dieldrin and carbofuran lost to the environment, we incorporated them into soils in small (0.6-1.1 ha) watersheds in separate years. The disappearance of each was monitored by periodically measuring residues in the soil, runoff, maize plants, and overlying air (dieldrin only). Soil residues were nonuniformly distributed. Best estimate for the time for 95% disappearance of dieldrin from the soil was 12.8 years. Carbofuran disappearance conformed to a first-order reaction and gave 95% disappearance times ranging from 145 to 434 days, depending on soil pH, moisture, and temperature. Runoff losses of both pesticides were highest in rainfalls during the first month after application. Over the season, dieldrin losses ranged up to 2.3% of that applied and were concentrated in the solids. Carbofuran losses in runoff occurred largely in the water and comprised up to 1.9% of the application. More than twice as much carbofuran (and metabolites) as dieldrin was accumulated in the maize plants, mainly in the leaves. Volatilization was an important route of dieldrin loss, amounting in the first year to 4.5% of that applied. Volatility of carbofuran, which was only 1/18th that of dieldrin in a laboratory test, was not measured in the field. The data show that use of optimum management practices can substantially reduce the environmental impact of agricultural applications of these pesticides.

Air

Dieldrin-14C elimination from chickens.

A series of experiments was conducted with chickens contaminated with dieldrin-14C to find ways of accelerating the elimination of dieldrin from their bodies. The results of these experiments indicated that charcoal, imbiber beads, and the anion exchanges resins, Dowex XFS-4022 and Dowex SBR-C1, would not be useful agents for increasing the amount of dieldrin eliminated via feces (droppings) of chickens. Further, imbiber beads coalesced in the gizzard of the chickens and reduced their appetites. The anion exchange resin, cholestyramine, might be useful as gastrointestinal absorbant for increasing dieldrin elimination in chickens because it increased carbon-14 elimination in droppings, but its effect on carbon-14 residues in carcasses was not clear. We elected not to investigate this compound further. Probucol, investigated because it might alter gastrointestinal absorption or blood physiology that would affect dieldrin elimination, did not increase dieldrin elimination. Severe starvation was the only method investigated that clearly was useful for increasing dieldrin elimination because it increased carbon-14 elimination in droppings and reduced carbon-14 residues in carcasses.

Animals

Suppression of avidin processing and presentation by mouse macrophages after sublethal exposure to dieldrin.

The molecular events in macrophage antigen processing and presentation were examined to determine the possible site(s) of cell-xenobiotic interaction. Antigenic processing by mouse peritoneal macrophages of a single protein antigen, avidin, was significantly suppressed following sublethal exposure of animals to an organochlorine pesticide, dieldrin. Exposure of C57B1/6 female mice to dieldrin affected the in vitro uptake of [methyl-14C]avidin by peritoneal macrophages and markedly decreased phagocytosis of fluorescein-labelled microspheres and Salmonella typhimurium. Release of the processed avidin, determined by immunochemical quantification of immunogenic avidin and by bioassay of immunogenicity of the released antigen, was also markedly affected. Dieldrin markedly affected presentation of avidin on the macrophage surface, observed by cytoimmunochemical staining of the antigen with fluorescent antibody and flow cytometry. Inhibition of the release of processed avidin was dieldrin dose- and time-dependent, following single sublethal intraperitoneal (ip) exposure to the pesticide. The antigenic properties of processed avidin, determined by biological assay using lymphocyte cultures of normal C57B1/6 mice primed with avidin, were proportional to the antigen concentration in supernatants of macrophage cultures, for both vehicle controls and dieldrin-exposed animals. This observation and analysis of the kinetics of release of processed avidin by macrophages from control and dieldrin-exposed animals suggested that the release of processed avidin, but not the immunogenicity of the antigen itself, was affected by the pesticide exposure. Generally, impairment of avidin processing and presentation appeared to be more dramatic than other pesticide-related injuries to macrophages, such as the uptake of the antigen. In conclusion, antigen processing could be a sensitive target for dieldrin-related injury of macrophage functional activities, which, in consequence, could produce suppression of the humoral immune response.

Animals

Virus-pesticide interactions with murine cellular immunity after sublethal exposure to dieldrin and aminocarb.

Interaction of two potential immunosuppressive factors, sublethal pesticide exposure and viral inhibition of lymphocyte mitogenesis, was examined in mixed lymphocyte reaction (MLR). Inbred (C57Bl/6 x A/J)F mice, semisusceptible to mouse hepatitis virus 3 (MHV3) infection were exposed to selected pesticides and subsequently infected with the MHV3 virus. The mortality of animals was examined as a function of pesticide exposure. Two pesticides were selected for further studies: the organochlorine pesticide dieldrin, which increased the cumulative mortality of animals, and the carbamate pesticide aminocarb, which did not affect the virus-induced cumulative mortality of animals. Spleen lymphocytes from dieldrin- and aminocarb-exposed C57Bl/6 mice (susceptible to MHV3 infection) were used as responder cells in one-way MLR. A marked immunosuppression of the MLR proliferative response was observed in the dieldrin group, whereas sublethal exposure to aminocarb did not affect the in vitro MLR response. The MLR cultures were subsequently infected in vitro with the MHV3 virus, which resulted in a time-dependent and virus dose-dependent inhibition of lymphocyte proliferation. However, no synergism was observed with the addition of either the MHV3 virus-induced inhibition of in vitro MLR lymphoproliferative response or dieldrin-related immunosuppression, since in vitro MHV3 infection of cells from dieldrin-exposed mice did not aggravate the dieldrin-related immunosuppression. In addition, no "hidden" aminocarb-related damage of the lymphoproliferative response was noted, as the kinetics of the virus-induced inhibition in the aminocarb group were analogous to the control. In conclusion, dieldrin-induced immunosuppression of the cellular immune response, rather than MHV3 virus-induced inhibition of lymphoproliferative activity itself, was the primary factor potentially responsible for the impaired cellular response. Furthermore, the data support the observation that cell-mediated immunity can be a potential target for the adverse effects of pesticide exposure.

Animals

Strategies, systems, value judgements and dieldrin in control of locust hoppers.

The physiology and field biology of locusts have been extensively studied, and ecological control of Red Locusts has been investigated by field experiment. No fruitful or even promising non-insecticidal method of control has emerged. An effective and economical system requires an insecticide that is: (i) effective at very small area dosages, as a stomach poison placed on the natural vegetation can be, if it is also cumulative; (ii) persistent enough in sunshine and rain to retain effectiveness over the locust's non-feeding periods; (iii) capable of being well distributed by well-tried methods; and (iv) not dangerous to users or consumers and posing a minimal overall risk. Only one insecticide, dieldrin, satisfies all these requirements. Dieldrin is not in the small class of insecticides that are dangerous to man by skin absorption (such as parathion, arsenicals, DNC) and, at the area dosages needed for locust control, is not dangerous to stock. The Sayer exhaust sprayer in a Land Rover, with work rates of the order of square kilometres per hour is excellent for many situations; aircraft spraying at he rate of square kilometres per minute is quicker and less subject to difficulties of terrain, but requires trained and appropriately directed aircrew. Apart from checking, aircraft methods require no party on the ground to find, assess and control locust hoppers. Several ideas about dieldrin are found to be based on insufficient evidence and are probably not true: for example that dieldrin in the atmosphere at a few parts in a million million (10(12)) becomes concentrated in a food web and harmful to man, or that dieldrin is carcinogenic in man. It is noteworthy, however, that one species of antelope in South Africa is exceptionally susceptible to dieldrin poisoning, though harm occurs at area dosages considerably greater than are required in the method of aircraft spraying of Courshee & McDonald (1963). To attack tsetse flies, emissions two orders of magnitude greater have been used. Care must be taken with any insecticide, but the risks of using dieldrin as properly used in locust hopper control have been exaggerated by propaganda. If harm is to be expected, then a quantitative comparison of that with the undoubted benefits of locust control is required to enable one to make a value judgement.

Aircraft

Uptake and disposition of aldrin and dieldrin by isolated perfused rabbit lung.

The uptake, metabolism, and release of aldrin and dieldrin by the lungs were studied by use of isolated perfused rabbit lungs that were artificially ventilated and perfused through the pulmonary artery. Both recirculating and single-pass experiments were conducted using an artificial medium as perfusate. Aldrin accumulated in the lung from the perfusate through two distinct phases of uptake: a rapid phase involving simple diffusion and nonspecific binding and a slower phase representing its metabolic turnover as dieldrin. Dieldrin was not metabolized but accumulated in the lungs by a saturable and a nonsaturable process. Single-pass experiments with aldrin indicated that the initial velocity of uptake could be fitted to one component and a constant representing the rate of metabolism. Uptake of dieldrin was biphasic: one phase independent of the perfusate concentration and the other saturable with respect to the perfusate concentration. By the application of Michaelis-Menten kinetics, the maximum amount of dieldrin accumulation attributable to the saturable component was calculated to be 0.64 mumol/lung. Our results indicate that the accumulation of these chlorinated xenobiotics takes place through the processes of simple diffusion followed by nonspecific tissue binding. There was no evidence for irreversible binding of aldrin or dieldrin, its epoxide, in the lung. While the lung plays a role in metabolizing aldrin to dieldrin followed by a transient storage, neither substrate has the potential for long-term storage in the lung.

Aldrin

The morphologic effects of dieldrin and methyl mercuric chloride on pars recta segments of rat kidney proximal tubules.

This investigation was undertaken to evaluate the morphologic effects in rat kidney resulting from chronic exposure to low doses of the pesticide dieldrin, methyl mercuric chloride (CH(3)HgCl) and the combination of dieldrin plus CH(3)HgCl. Histologic and ultrastructural changes were confined to the proximal tubules. Alterations in these tubules were consistent and reproducible for each regimen and did not become more severe with duration of exposure. The straight segment of the proximal tubule (pars recta) was more severely affected by dieldrin and CH(3)HgCl than the convoluted portion. Female rats were more markedly affected than males. Pars recta tubule cells of male and female rats exposed to dieldrin showed an increase of smooth endoplasmic reticulum (SER). Male rats displayed a greater increase in SER than females. Pars recta tubule cells of animals given CH(3)HgCl also exhibited increased amounts of SER, degenerating mitochondria and cell death. Pars recta tubules of females were dilated and contained within the lumens many spherical, hematoxylin-positive staining, cytoplasmic masses, which were visible by light microscopy. These masses were characterized ultrastructurally by the presence of an SER aggregate in an area of material similar to cell matrix. In addition, cells of the pars recta of female animals contained electron-dense membranous cytosomes not present in control animals. Pars recta cells of males showed an increase in SER, but the dense membranous cytosomes observed in the pars recta cells of female rats were not seen. Rats exposed to dieldrin plus CH(3)CgCl showed less morphologic alteration of the pars recta tubules than animals given methyl mercuric chloride; however, increased amounts of SER and more degeneration in tubule cells were observed in these animals when compared to control animals. The findings are discussed in relation to the conversion of CH(3)HgCl to inorganic mercury in vivo and the known toxicity of inorganic mercury to the pars recta. Decreased tubular alteration in males and dieldrin-treated animals may be explained by sexual differences in renal enzyme levels or activities and the induction of microsomal enzyme systems by dieldrin.

Animals

Toxicity of dieldrin to bobwhite quail in relation to sex and reproductive status.

In a study of dieldrin toxicity to breeding and nonbreeding bob-white quail (Colinus virginianus), breeding birds of both sexes on long photoperiods were more susceptible to dieldrin poisoning than nonbreeding birds, although some differences were not statistically significant at the .10 level. Shortened photoperiods caused gonadal regression, weight loss, and additional mortalities among dieldrin-treated birds previously in breeding condition. Dieldrin did not influence food consumption, body weight, or egg production until about a week or less before death of individual birds. Dieldrin brain residues were higher among birds that died during the study than among survivors sacrificed at its termination. Among those that died, neither dieldrin treatment level, reproductive status, nor sex seemed related to brain residue levels. Nevertheless, within those factors, levels were slightly higher in the birds that died later in the test.

Animals

Suppression of MHV3 virus-activated macrophages by dieldrin.

Dieldrin (36 mg/kg body weight) administered intraperitoneally prolonged recovery from infection with mouse hepatitis virus 3 (MHV3) in the genetically-resistant A/J strain, affected the humoral anti-MHV3 IgG immune response, and inhibited the intrinsic antiviral activity of peritoneal macrophages upon in vitro rechallenge with the virus. Infection of untreated A/J animals and vehicle controls with MHV3 resulted in marked and reproducible activation of peritoneal macrophages, observed in vitro as resistance to MHV3-cytopathic effects 48 hr after rechallenge with the virus, whereas exposure to dieldrin resulted in apparent loss of the intrinsic capacity of cells to restrict replication of MHV3 and to protect them from cytolysis. In addition, in vitro treatment of MHV3 virus-activated macrophages with dieldrin, mitomycin C and X-irradiation, inhibited the intrinsic capacity of cells to restrict MHV3 replication. This mechanism of cellular restriction of the virus by MHV3-activated macrophages from the resistant A/J strain appeared to be one of the sensitive targets for the suppressive action of dieldrin on host resistance, as no major changes in macrophage cellular parameters were observed in in vitro studies of cell viability, adherence to plastic, and superoxide anion generation; the increased cell yield in the peritoneal exudates during MHV3 virus infection was not affected by dieldrin exposure; and the attachment and uptake of [3H]MHV3 by virus-activated macrophages was shown to be unchanged by dieldrin exposure.

Animals

A pesticide (dieldrin)-induced immunohemolytic anemia.

The unusual presentation of a factory worker with severe hemolytic anemia which remitted following splenectomy prompted a search for an environmental cause for red cell injury. The investigation showed the presence of an immunoglobulin in the patient's serum and on the red cells and small amounts of complement on red cells. The patient's serum caused agglutination of a normal person's red cells only when dieldrin-coated, a reaction blocked by first reacting the serum with dieldrin. The spleen of the patient had a greater than normal concentration of dieldrin, the source of dieldrin being dietary. It is concluded that dieldrin became immunogenic and provoked a chemical immunohemolytic anemia. The spleen played a major role in destruction of red cells injured by the immunopathic process and in accumulation of the antigenic substance dieldrin.

Anemia, Hemolytic