Heptachlor
Heptachlor Epoxide
Chlordan
Aldrin
Hydrocarbons, Chlorinated
Insecticides
Dieldrin
Polarography
Lindane
Pesticides
Pesticide Residues
Mineral Oil
Neurotoxicological outcomes of perinatal heptachlor exposure in the rat. (1/22)
The developing nervous system has been identified as a potential target of pesticide exposure. Heptachlor is a cyclodiene pesticide that was widely used for many years, and for which inadvertent exposure to children and fetuses took place in the early 1980s; yet little is known regarding the developmental neurotoxicity of it and other cyclodienes. The aim of this study was to determine whether perinatal heptachlor exposure results in persistent alterations in nervous system function. Pregnant Sprague-Dawley dams were dosed from gestational day (GD) 12 to postnatal day (PND) 7, whereupon the rat pups were dosed directly until PND 21 (group A) or PND 42 (group B). Dose levels were 0, 0.03, 0.3, or 3 mg/kg/day, po. There were no dose-related effects on maternal weight, litter size, or pup growth. GABA(A) receptor binding (using [(35)S] tert-butylbicyclophosphorothionate; TBPS) and GABA-stimulated Cl- flux were evaluated in control and high-dose brain tissues taken on PND 7, 21, and 43. The B(max) values for [(35)S]-TBPS binding in brainstem, but not cortex, were decreased in female rats across all ages tested. There were no such changes in male rats, nor were K(D) values altered in either tissue or gender. GABA-stimulated Cl- flux was decreased in female cortex synaptoneurosomes only on PND 21. The ontogeny of the righting response (PND 2-5) was delayed in the high-dose females. All subsequent testing took place a week to months after dosing ceased. The functional observational battery (FOB) showed treatment-related, but not necessarily dose-related, changes in different aspects of the rat's reactivity and activity levels. Group-A rats also showed altered within-session habituation of motor activity. There were no heptachlor-related differences in motor activity following challenge with a range of chlordiazepoxide doses. Cognitive assessments were conducted in both groups of rats. There were no statistically significant differences among treatment groups in a one-trial passive avoidance test, although there was a trend toward less learning. In group B, rats (both sexes), heptachlor altered spatial learning in the Morris water maze during two weeks of daily training (2 trials/day). On probe trials, heptachlor-treated rats did not show significant preference for the correct quadrant (all dose groups in males, high dose in females). These rats did not show alterations on subsequent working-memory training (where the platform position was relearned each day). Thus, perinatal exposure to heptachlor produced neurochemical and persistent neurobehavioral changes, including alterations in spatial learning and memory. (+info)Neurotoxicity of the organochlorine insecticide heptachlor to murine striatal dopaminergic pathways. (2/22)
Changes in biochemical status of nerve terminals in the corpus striatum, one of the primary brain regions affected in Parkinson's disease, were studied in groups of C57BL/6 mice treated by ip injection three times over a 2-week period with 3--100 mg/kg heptachlor. On average, the maximal rate of striatal dopamine uptake increased > 2-fold in mice treated at doses of 6 mg/kg heptachlor and 1.7-fold at 12 mg/kg heptachlor. Increases in maximal rate of striatal dopamine uptake were attributed to induction of the dopamine transporter (DAT) and a compensatory response to elevated synaptic levels of dopamine. Significant increase in V(max) of striatal DAT was not observed at doses > 12 mg/kg, which suggested that toxic effects of heptachlor epoxide may be responsible for loss of maximal dopamine uptake observed at higher doses of heptachlor. In support of this conclusion, polarigraphic measurements of basal synaptosomal respiration rates from mice treated with doses of heptachlor > 25 mg/kg indicated marked, dose-dependent depression of basal tissue respiration. At doses of 6 and 12 mg/kg heptachlor, which increased expression of striatal DAT, uptake of 5-hydroxytryptamine into cortical synaptosomes was unaffected. Thus, striatal dopaminergic nerve terminals were found to be differentially sensitive to heptachlor. This reduced sensitivity of serotonergic pathways was mirrored in the greater potency of heptachlor epoxide to cause release of dopamine from preloaded striatal synaptosomes in vitro compared to release of serotonin from cortical membranes. These results suggest that heptachlor, and perhaps other organochlorine insecticides, exert selective effects on striatal dopaminergic neurons and may play a role in the etiology of idiopathic Parkinson's disease. (+info)The effects of perinatal/juvenile heptachlor exposure on adult immune and reproductive system function in rats. (3/22)
This study was performed to determine if developmental exposure of rats to heptachlor (H) during the last half of gestation through puberty adversely affects adult functioning of the immune and reproductive systems. Time-bred pregnant female Sprague-Dawley rats were dosed by gavage with H (0, 30, 300, or 3000 microg/kg/day) from gestation day (GD) 12 to postnatal day (PND) 7, followed by direct dosing of the pups with H through PND 42. Separate groups of rats were evaluated with a battery of immune function tests, while other groups of rats were evaluated for reproductive development and function. Additional groups of rats were euthanized at the end of the dosing period for histological analyses of major organ systems. Some dams and PND 7 pups were euthanized; milk, plasma, fat and/or tissues were assayed for H and heptachlor epoxide B (HEB), a major metabolite of H. The amount of H and HEB found in milk, blood, fat, and tissues was proportional to the dose of H administered. There were no effects on the number or survival of pups born to H-exposed dams nor to pups exposed postnatally. There were no effects on the number of treated dams delivering litters or on litter size, nor were there any effects on any of the reproductive end points examined in the F(0) or F(1) rats. There were no effects of H exposure on lymphoid organ weights, splenic natural killer (NK) cell activity, and splenic lymphoproliferative (LP) responses to mitogens and allogeneic cells in a mixed lymphocyte response (MLR) assay at 8 weeks of age. H exposure did not alter delayed or contact hypersensitivity at 10 or 17 weeks of age, respectively. However, the primary IgM antibody response to sheep red blood cells (SRBCs) was suppressed in a dose-dependent manner in males, but not females, at 8 weeks of age. The percentage of B lymphocytes (OX12(+)OX19(-)) in spleen was also reduced in the high-dose males. The anti-SRBC IgM response was reduced only in males exposed to 30 microg H/kg/day in a separate group of rats 21 weeks of age. In these same rats, at 26 weeks of age, the secondary IgG antibody response to SRBCs was suppressed in all of the H-exposed males, but not females. These data indicate that perinatal exposure of male rats to H results in suppression of the primary IgM and secondary IgG anti-SRBC responses. Suppression of these antibody responses persisted for up to 20 weeks after the last exposure to H, at a total exposure of approximately 1500 microg H/kg/rat. (+info)Dopamine transporter binding in the rat striatum is increased by gestational, perinatal, and adolescent exposure to heptachlor. (4/22)
Heptachlor is a persistent cyclodiene pesticide that affects GABAergic function. Recent reports indicate that heptachlor exposure also alters dopamine transporter (DAT) expression and function in adult mice. The aim of this study was to determine whether gestational, perinatal, and/or adolescent heptachlor exposure in rats altered dopamine-receptor and DAT binding. Adolescent exposure to dieldrin was included to evaluate the generality of the findings. Sprague-Dawley rats received doses (po) ranging from 0 to 8.4 mg/kg/day of heptachlor, or dieldrin, 3 mg/kg/day, during different developmental periods. There were dose-related decreases in maternal weight gain and pup survival, as well as delayed righting reflex, at heptachlor doses > or =3 mg/kg/day. There were no changes in striatal dopamine receptor-D1 ([(3)H]SCH-23390) and -D2 ([(3)H]spiperone) binding in preweanling pups exposed perinatally to heptachlor, and no differences in the response of adult rats to the motor activity-increasing effects of d-amphetamine. However, there were significant (27-64%) increases in striatal DAT binding of [(3)H]mazindol in preweanling rats exposed only gestationally. In rats exposed perinatally and/or during adolescence, there were also increases (34-65%) in striatal DAT binding at postnatal days (PND) 22, 43, and 128. Adolescent exposure to dieldrin also increased DAT binding. In other rats exposed perinatally and throughout adolescence, even the lowest dose of heptachlor 0.3 mg/kg/d increased DAT binding on PND 130. The DAT affinity for mazindol was unchanged in heptachlor-exposed striata. In vitro binding studies indicated that heptachlor (> or =10 microM) displaced mazindol binding. Thus, gestational, perinatal, and/or adolescent exposure to heptachlor produced an increase in DAT binding as early as PND 10, and this change persisted into adulthood. (+info)Comparative biodegradation of alkyl halide insecticides by the white rot fungus, Phanerochaete chrysosporium (BKM-F-1767). (5/22)
The ability of Phanerochaete chrysosporium to degrade six alkyl halide insecticides (aldrin, dieldrin, heptachlor, chlordane, lindane, and mirex) in liquid and soil-corncob matrices was compared by using 14C-labeled compounds. Of these, only [14C]lindane and [14C]chlordane underwent extensive biodegradation, as evidenced by the fact that 9.4 to 23.4% of these compounds were degraded to 14CO2 in 30 days in liquid cultures and 60 days in soil-corncob cultures inoculated with P. chrysosporium. Although [14C]aldrin, [14C]dieldrin, [14C]heptachlor, and [14D]mirex were poorly mineralized, substantial bioconversion occurred, as determined by substrate disappearance and metabolite formation. Nonbiological disappearance was observed only with chlordane and heptachlor. (+info)Occupational exposure to organochlorine insecticides and cancer incidence in the Agricultural Health Study. (6/22)
Organochlorine (OC) insecticides have been regulated as possible human carcinogens primarily on the basis of animal studies. However, the epidemiologic evidence is inconsistent. We investigated the relationship between cancer incidence and OC insecticide use among pesticide applicators enrolled in the Agricultural Health Study, a prospective cohort study of 57,311 licensed applicators in Iowa and North Carolina enrolled between 1993 and 1997. Information on ever use of 7 OC insecticides (aldrin, chlordane, DDT, dieldrin, heptachlor, lindane, toxaphene) was collected from a self-administered questionnaire at enrollment. Lifetime exposure-days to OC insecticides were calculated using additional data from a take-home questionnaire completed by 25,291 participants (44% of total). We found no clear evidence of an association between use of OC insecticides and incident cancers (N = 1,150) ascertained through December, 2002. When we focused on individual insecticides and structurally similar groups (aldrin and dieldrin; chlordane and heptachlor), significantly increased relative risks of some cancers were observed for use of some chemicals (rectal cancer and chlordane, lung cancer and dieldrin, non-Hodgkin lymphoma (NHL) and lindane, melanoma and toxaphene, leukemia and chlordane/heptachlor). Some significant decreased relative risks were also observed (colon cancer and aldrin; overall cancer and heptachlor). In conclusion, we did not observe any clear relationship between cancer risk and the use of OC insecticides. Our chemical-specific findings are based on small numbers and multiple comparisons, and should be interpreted with caution; however, some observed associations (lindane and NHL, chlordane/heptachlor and leukemia) are supported by previous evidence. (+info)Pesticide use and chronic bronchitis among farmers in the Agricultural Health Study. (7/22)
BACKGROUND: Farmers have increased risk for chronic bronchitis. Few investigators have considered pesticides. METHODS: We evaluated pesticides as risk factors for chronic bronchitis using the Agricultural Health Study enrollment data on lifetime pesticide use and history of doctor-diagnosed chronic bronchitis from 20,908 private pesticide applicators, primarily farmers. RESULTS: A total of 654 farmers (3%) reported chronic bronchitis diagnosed after age 19. After adjustment for correlated pesticides as well as confounders, 11 pesticides were significantly associated with chronic bronchitis. Heptachlor use had the highest odds ratio (OR=1.50, 95% Confidence Interval (CI)=1.19, 1.89). Increased prevalence for chronic bronchitis was also seen for individuals who had a history of a high pesticide exposure event (OR=1.85, 95% CI=1.51, 2.25) and for those who also applied pesticides in off-farm jobs (OR=1.40, 95% CI=1.04, 1.88). Co-morbid asthma and current farm activities did not explain these results. CONCLUSIONS: These results provide preliminary evidence that pesticide use may increase chronic bronchitis prevalence. (+info)Developmental heptachlor exposure increases susceptibility of dopamine neurons to N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)in a gender-specific manner. (8/22)
(+info)Heptachlor is a synthetic, chlorinated hydrocarbon insecticide that was widely used in the past for agricultural and residential pest control. It is a colorless to white crystalline solid with a mild chemical odor. Heptachlor is highly toxic to both insects and mammals, including humans. It can cause damage to the liver and nervous system, and long-term exposure has been linked to cancer in animals.
Heptachlor was banned for most uses in the United States in 1978 due to its persistence in the environment and potential health risks. However, it can still be found in some older pesticide formulations and in contaminated soil, water, and air. Heptachlor is highly persistent in the environment and can accumulate in the food chain, posing a risk to wildlife and human health.
Heptachlor epoxide is a metabolite and environmental breakdown product of heptachlor, which is a chlorinated hydrocarbon insecticide. It is an organochlorine compound that was widely used in the past for agricultural and residential pest control purposes, including termite treatments and crop protection.
Heptachlor epoxide is formed through the oxidation of heptachlor by various biological and environmental processes. It is more stable and persistent in the environment compared to heptachlor, making it a significant contaminant in soil, water, and air. Heptachlor epoxide has been classified as a probable human carcinogen by the International Agency for Research on Cancer (IARC) and the United States Environmental Protection Agency (EPA). It can accumulate in the fatty tissues of living organisms, including humans, and poses potential risks to human health and the environment.
Chlordane is a man-made chlorinated hydrocarbon compound that was widely used as a pesticide, particularly for termite control, from the 1940s until it was banned in the United States in 1988 due to its toxicity and persistence in the environment. It is a colorless or light brown liquid with a mild, aromatic odor.
Chlordane is an extremely toxic compound to insects and has been shown to have negative effects on human health as well. Exposure to chlordane can cause a range of adverse health effects, including neurological damage, liver toxicity, and an increased risk of cancer. It is classified as a probable human carcinogen by the International Agency for Research on Cancer (IARC) and the United States Environmental Protection Agency (EPA).
Chlordane is highly persistent in the environment and can accumulate in the food chain, posing a particular risk to wildlife and humans who consume contaminated food or water. It can also volatilize from soil and water into the air, where it can be transported long distances and contribute to air pollution. As a result, chlordane continues to pose a significant environmental and health hazard, even though its use has been banned for several decades.
Aldrin is a chemical compound with the formula C12H15ClN2. It is an organochlorine insecticide that was widely used in the past for agricultural and household pest control. Aldrin is a gray, crystalline solid that is almost insoluble in water but soluble in organic solvents.
Aldrin is a persistent organic pollutant (POP) that can accumulate in the fatty tissues of living organisms and pose a risk to human health and the environment. It has been banned or restricted in many countries due to its toxicity and environmental persistence.
In humans, exposure to aldrin can cause a range of health effects, including headaches, dizziness, nausea, vomiting, muscle weakness, tremors, and convulsions. Long-term exposure has been linked to damage to the nervous system, liver, and kidneys, as well as an increased risk of cancer.
It's important to note that Aldrin is not a medical term, but a chemical one. Therefore, it doesn't have a medical definition in terms of a condition or disease, but rather as a chemical compound with certain properties and uses, as well as potential health risks.
Chlorinated hydrocarbons are a group of organic compounds that contain carbon (C), hydrogen (H), and chlorine (Cl) atoms. These chemicals are formed by replacing one or more hydrogen atoms in a hydrocarbon molecule with chlorine atoms. The properties of chlorinated hydrocarbons can vary widely, depending on the number and arrangement of chlorine and hydrogen atoms in the molecule.
Chlorinated hydrocarbons have been widely used in various industrial applications, including as solvents, refrigerants, pesticides, and chemical intermediates. Some well-known examples of chlorinated hydrocarbons are:
1. Methylene chloride (dichloromethane) - a colorless liquid with a mild sweet odor, used as a solvent in various industrial applications, including the production of pharmaceuticals and photographic films.
2. Chloroform - a heavy, volatile, and sweet-smelling liquid, used as an anesthetic in the past but now mainly used in chemical synthesis.
3. Carbon tetrachloride - a colorless, heavy, and nonflammable liquid with a mildly sweet odor, once widely used as a solvent and fire extinguishing agent but now largely phased out due to its ozone-depleting properties.
4. Vinyl chloride - a flammable, colorless gas, used primarily in the production of polyvinyl chloride (PVC) plastic and other synthetic materials.
5. Polychlorinated biphenyls (PCBs) - a group of highly stable and persistent organic compounds that were widely used as coolants and insulating fluids in electrical equipment but are now banned due to their toxicity and environmental persistence.
Exposure to chlorinated hydrocarbons can occur through inhalation, skin contact, or ingestion, depending on the specific compound and its physical state. Some chlorinated hydrocarbons have been linked to various health effects, including liver and kidney damage, neurological disorders, reproductive issues, and cancer. Therefore, proper handling, use, and disposal of these chemicals are essential to minimize potential health risks.
Insecticides are substances or mixtures of substances intended for preventing, destroying, or mitigating any pest, including insects, arachnids, or other related pests. They can be chemical or biological agents that disrupt the growth, development, or behavior of these organisms, leading to their death or incapacitation. Insecticides are widely used in agriculture, public health, and residential settings for pest control. However, they must be used with caution due to potential risks to non-target organisms and the environment.
Dieldrin is a chlorinated hydrocarbon insecticide that was widely used in the past for agricultural and household pest control. It is a white, odorless, crystalline solid that is insoluble in water but soluble in organic solvents. Dieldrin has high toxicity to both insects and mammals, including humans. It can cause a range of harmful health effects, such as seizures, damage to the nervous system, and liver and kidney damage. Dieldrin was banned for most uses in the United States in 1974 due to its persistence in the environment and potential to accumulate in the food chain. It is now classified as a persistent organic pollutant (POP) and is regulated under international treaties.
Polarography is a type of electrochemical analysis technique used to determine the concentration of an ion or electron-transferring species in a solution. It involves measuring the current that flows through an electrode as the voltage is varied, which can provide information about the redox potential and the number of electrons transferred during a reaction. The technique is particularly useful for analyzing complex mixtures and for detecting trace amounts of substances.
In polarography, a dropping mercury electrode (DME) is typically used as the working electrode. As the mercury droplets fall from the electrode, they create fresh surfaces for analysis, which helps to minimize interference from surface-adsorbed species. The DME is immersed in a solution containing the analyte along with a supporting electrolyte, and a potential is applied between the DME and a reference electrode.
As the potential is scanned, reduction or oxidation of the analyte occurs at the DME surface, leading to a current that can be measured. The resulting polarogram (a plot of current vs. voltage) shows peaks or waves corresponding to the redox potentials of the analyte, which can be used to identify and quantify the species present in the solution.
Polarography is a sensitive and selective technique that has been widely used in fields such as environmental analysis, pharmaceuticals, and biochemistry. However, it has largely been replaced by more modern electrochemical techniques, such as cyclic voltammetry and differential pulse voltammetry, which offer higher sensitivity and better resolution of complex mixtures.
Radioactive soil pollutants refer to radioactive substances that contaminate and negatively impact the chemical, physical, and biological properties of soil. These pollutants can arise from various sources such as nuclear accidents, industrial activities, agricultural practices, and military testing. They include radionuclides such as uranium, plutonium, cesium-137, and strontium-90, among others.
Exposure to radioactive soil pollutants can have serious health consequences for humans and other living organisms. Direct contact with contaminated soil can result in radiation exposure, while ingestion or inhalation of contaminated soil particles can lead to internal radiation exposure. This can increase the risk of cancer, genetic mutations, and other health problems.
Radioactive soil pollutants can also have negative impacts on the environment, such as reducing soil fertility, disrupting ecosystems, and contaminating water sources. Therefore, it is essential to monitor and regulate radioactive soil pollution to protect human health and the environment.
Lindane is defined in medical terms as an agricultural and pharmaceutical compound that contains thegamma-isomer of hexachlorocyclohexane (γ-HCH). It has been used as a topical treatment for scabies and lice infestations, although its use is now limited due to concerns about toxicity and environmental persistence. Lindane works by disrupting the nervous system of insects, leading to paralysis and death. However, it can also have similar effects on mammals, including humans, at high doses or with prolonged exposure. Therefore, its use is restricted and alternatives are recommended for the treatment of scabies and lice.
Pesticides are substances or mixtures of substances intended for preventing, destroying, or repelling pests. Pests can be insects, rodents, fungi, weeds, or other organisms that can cause damage to crops, animals, or humans and their living conditions. The term "pesticide" includes all of the following: insecticides, herbicides, fungicides, rodenticides, bactericides, and various other substances used to control pests.
It is important to note that while pesticides are designed to be toxic to the target pests, they can also pose risks to non-target organisms, including humans, if not used properly. Therefore, it is essential to follow all label instructions and safety precautions when handling and applying pesticides.
Pesticide residues refer to the remaining pesticide chemicals, including their metabolites and degradation products, that are present in or on food commodities or environmental samples after a pesticide application has ended. These residues can result from agricultural use, such as spraying crops to control pests, or from non-agricultural uses, like treating buildings for termite control.
Regulatory agencies establish maximum residue limits (MRLs) to ensure that the levels of pesticide residues in food and feed are below those that may pose a risk to human health. Monitoring programs are in place to check compliance with these MRLs, and enforcement actions can be taken if violations occur.
It's important to note that not all pesticide residues are harmful, as some pesticides degrade into harmless compounds over time or leave behind residues below levels of concern for human health. However, long-term exposure to even low levels of certain pesticide residues may still pose a risk and should be avoided when possible.
Medical Definition of Mineral Oil:
Mineral oil is a commonly used laxative, which is a substance that promotes bowel movements. It is a non-digestible, odorless, and tasteless oil that is derived from petroleum. When taken orally, mineral oil passes through the digestive system without being absorbed, helping to soften stools and relieve constipation by increasing the weight and size of the stool, stimulating the reflexes in the intestines that trigger bowel movements.
Mineral oil is also used topically as a moisturizer and emollient for dry skin conditions such as eczema and dermatitis. It forms a barrier on the skin, preventing moisture loss and protecting the skin from irritants. However, mineral oil should not be used on broken or inflamed skin, as it can trap bacteria and delay healing.
It is important to note that long-term use of mineral oil laxatives can lead to dependence and may interfere with the absorption of fat-soluble vitamins such as A, D, E, and K. Therefore, it should be used only under the guidance of a healthcare professional.
Mirex is not typically defined in a medical context as it is not a medical term. However, Mirex is a chemical compound that was previously used as an insecticide and flame retardant. It is a colorless solid with a weak chemical odor and is highly stable, which led to its use in various applications.
In the medical field, Mirex may be mentioned in relation to environmental health or toxicology due to its potential harmful effects on human health. Exposure to Mirex can occur through contaminated food, water, or air, and it has been linked to several adverse health outcomes, including neurological damage, reproductive problems, and cancer. However, the use of Mirex as an insecticide has been banned in many countries due to its environmental and health hazards.