An organothiophosphate cholinesterase inhibitor that is used as an insecticide and as an acaricide.
Pesticides designed to control insects that are harmful to man. The insects may be directly harmful, as those acting as disease vectors, or indirectly harmful, as destroyers of crops, food products, or textile fabrics.
A cholinesterase inhibitor that is used as an organothiophosphorus insecticide.
Drugs that inhibit cholinesterases. The neurotransmitter ACETYLCHOLINE is rapidly hydrolyzed, and thereby inactivated, by cholinesterases. When cholinesterases are inhibited, the action of endogenously released acetylcholine at cholinergic synapses is potentiated. Cholinesterase inhibitors are widely used clinically for their potentiation of cholinergic inputs to the gastrointestinal tract and urinary bladder, the eye, and skeletal muscles; they are also used for their effects on the heart and the central nervous system.
Pyridine derivatives with one or more keto groups on the ring.
Cholinesterases are a group of enzymes that catalyze the hydrolysis of acetylcholine and other choline esters, playing crucial roles in the termination of impulse transmission at cholinergic synapses and neuro-muscular junctions, and in the metabolism of certain drugs and toxic substances.
Pesticides or their breakdown products remaining in the environment following their normal use or accidental contamination.
A highly toxic cholinesterase inhibitor that is used as an acaricide and as an insecticide.
Chemicals used to destroy pests of any sort. The concept includes fungicides (FUNGICIDES, INDUSTRIAL); INSECTICIDES; RODENTICIDES; etc.
The reduction or regulation of the population of noxious, destructive, or dangerous plants, insects, or other animals. This includes control of plants that serve as habitats or food sources for animal pests.
An enzyme that catalyzes the hydrolysis of ACETYLCHOLINE to CHOLINE and acetate. In the CNS, this enzyme plays a role in the function of peripheral neuromuscular junctions. EC 3.1.1.7.
An organochlorine insecticide whose use has been cancelled or suspended in the United States. It has been used to control locusts, tropical disease vectors, in termite control by direct soil injection, and non-food seed and plant treatment. (From HSDB)
Neurologic disorders caused by exposure to toxic substances through ingestion, injection, cutaneous application, or other method. This includes conditions caused by biologic, chemical, and pharmaceutical agents.
An organophosphate cholinesterase inhibitor that is used as a pesticide.
Carbon-containing phosphoric acid derivatives. Included under this heading are compounds that have CARBON atoms bound to one or more OXYGEN atoms of the P(=O)(O)3 structure. Note that several specific classes of endogenous phosphorus-containing compounds such as NUCLEOTIDES; PHOSPHOLIPIDS; and PHOSPHOPROTEINS are listed elsewhere.
An aspect of cholinesterase (EC 3.1.1.8).
A carbamate insecticide and parasiticide. It is a potent anticholinesterase agent belonging to the carbamate group of reversible cholinesterase inhibitors. It has a particularly low toxicity from dermal absorption and is used for control of head lice in some countries.
Poisoning due to exposure to ORGANOPHOSPHORUS COMPOUNDS, such as ORGANOPHOSPHATES; ORGANOTHIOPHOSPHATES; and ORGANOTHIOPHOSPHONATES.
Carboxylesterase is a serine-dependent esterase with wide substrate specificity. The enzyme is involved in the detoxification of XENOBIOTICS and the activation of ester and of amide PRODRUGS.
An agent used as a substrate in assays for cholinesterases, especially to discriminate among enzyme types.
The methyl homolog of parathion. An effective, but highly toxic, organothiophosphate insecticide and cholinesterase inhibitor.
Pesticides used to destroy unwanted vegetation, especially various types of weeds, grasses (POACEAE), and woody plants. Some plants develop HERBICIDE RESISTANCE.
Graphic representations, especially of the face, of real persons, usually posed, living or dead. (From Thesaurus for Graphic Materials II, p540, 1995)
The planning of the furnishings and decorations of an architectural interior.
Organic compounds that contain phosphorus as an integral part of the molecule. Included under this heading is broad array of synthetic compounds that are used as PESTICIDES and DRUGS.
A plant genus of the family SALICACEAE. Members contain salicin, which yields SALICYLIC ACID.
The science, art or practice of cultivating soil, producing crops, and raising livestock.
The active insecticidal constituent of CHRYSANTHEMUM CINERARIIFOLIUM flowers. Pyrethrin I is the pyretholone ester of chrysanthemummonocarboxylic acid and pyrethrin II is the pyretholone ester of chrysanthemumdicarboxylic acid monomethyl ester.
Potent cholinesterase inhibitor used as an insecticide and acaricide.
A mitosporic Loculoascomycetes fungal genus including some economically important plant parasites. Teleomorphs include Mycosphaerella and Venturia.
N,N',N'',N'''-Tetraisopropylpyrophosphamide. A specific inhibitor of pseudocholinesterases. It is commonly used experimentally to determine whether pseudo- or acetylcholinesterases are involved in an enzymatic process.
A mixture of isomeric tritolyl phosphates. Used in the sterilization of certain surgical instruments and in many industrial processes.
Standards for limiting worker exposure to airborne contaminants. They are the maximum concentration in air at which it is believed that a particular substance will not produce adverse health effects with repeated daily exposure. It can be a time-weighted average (TLV-TWA), a short-term value (TLV-STEL), or an instantaneous value (TLV-Ceiling). They are expressed either as parts per million (ppm) or milligram per cubic meter (mg/m3).
A wide spectrum aliphatic organophosphate insecticide widely used for both domestic and commercial agricultural purposes.
The exposure to potentially harmful chemical, physical, or biological agents in the environment or to environmental factors that may include ionizing radiation, pathogenic organisms, or toxic chemicals.

Comparison of two in vitro activation systems for protoxicant organophosphorous esterase inhibitors. (1/305)

In order to perform in vitro testing of esterase inhibition caused by organophosphorous (OP) protoxicants, simple, reliable methods are needed to convert protoxicants to their esterase-inhibiting forms. Incubation of parathion or chlorpyrifos with 0.05% bromine solution or uninduced rat liver microsomes (RLM) resulted in production of the corresponding oxygen analogs of these OP compounds and markedly increased esterase inhibition in SH-SY5Y human neuroblastoma cells. Neither activation system affected cell viability or the activity of AChE or NTE in the absence of OP compounds. Although parathion and chlorpyrifos were activated by RLM, bromine activation required fewer steps and produced more esterase inhibition for a given concentration of chlorpyrifos. However, RLM activation of OP protoxicants produced metabolites other than oxygen analogs and may, therefore, be more relevant as a surrogate for OP biotransformation in vivo. This methodology makes the use of intact cells for in vitro testing of esterase inhibition caused by protoxicant organophosphate compounds a viable alternative to in vivo tests.  (+info)

Developmental cholinotoxicants: nicotine and chlorpyrifos. (2/305)

The stimulation of cholinergic receptors in target cells during a critical developmental period provides signals that influence cell replication and differentiation. Accordingly, environmental agents that promote cholinergic activity evoke neurodevelopmental damage because of the inappropriate timing or intensity of stimulation. Nicotine evokes mitotic arrest in brain cells possessing high concentrations of nicotinic cholinergic receptors. In addition, the cholinergic overstimulation programs the expression of genes that evoke apoptosis and delayed cell loss. Effects of cholinesterase inhibitors exhibit many similarities to those of nicotine. Chlorpyrifos administered to developing rats in doses that do not evoke signs of overt toxicity decreased DNA synthesis and caused shortfalls in cell numbers in brain regions enriched in cholinergic innervation. In embryo cultures, chlorpyrifos also evoked apoptosis during neurulation. However, chlorpyrifos also evokes noncholinergic disruption of cell development by interfering with cell signaling via adenylyl cyclase, leading to widespread disruption that is not limited to cholinergic systems. We have tested this hypothesis in vitro with PC12 cells, which lack the enzymes necessary to produce chlorpyrifos oxon, the metabolite that inhibits cholinesterase. Chlorpyrifos inhibited DNA synthesis in undifferentiated PC12 cells, which have relatively few cholinergic receptors. Furthermore, chlorpyrifos was more effective than nicotine and its effects were not blocked by cholinergic antagonists. When cells were allowed to differentiate in the presence of chlorpyrifos, cell replication was inhibited even more profoundly and cell acquisition was arrested. At higher concentrations, chlorpyrifos also inhibited neuritic outgrowth. Thus, chlorpyrifos elicits damage by both noncholinergic and cholinergic mechanisms extending from early stages of neural cell replication through late stages of axonogenesis and terminal differentiation. Accordingly, the window of developmental vulnerability to chlorpyrifos is likely to extend from the embryonic period into postnatal life.  (+info)

Dermal transfer of chlorpyrifos residues from residential surfaces: comparison of hand press, hand drag, wipe, and polyurethane foam roller measurements after broadcast and aerosol pesticide applications. (3/305)

Indoor residential pesticide applications present the potential for human exposures, particularly for small children. Personal contact with target and nontarget surfaces can result in transfer of pesticides to the skin, but the magnitude of such transfer is uncertain. This research compared surface sampling techniques [wipe and polyurethane foam (PUF) roller] with the removal ability of human skin following broadcast and total aerosol release applications of Dursban (Dow Elanco, Midland, MI), a residential formulation containing the insecticide chlorpyrifos. Hands were washed immediately after surface contact, following a protocol that included a laboratory-generated adjustment factor to account for incomplete removal of chlorpyrifos from skin. Chlorpyrifos transfer was similar for hand press and hand drag techniques, averaging approximately 1-6 ng/cm2 of carpet contacted. These amounts represented < 1% of the amount of chlorpyrifos deposited on the surfaces 3.5 hr earlier. Chlorpyrifos transfer from carpet to skin was 23-24 times lower than for wipe sampling and 33-36 times lower than for PUF roller sampling (p = 0.0007 and p = 0.0006 for broadcast and aerosol applications, respectively). Hand press sampling removed approximately 4.5 times less chlorpyrifos from nontarget furniture surfaces (12 ng/cm2) than did wipe sampling (56 ng/cm2; p = 0.009). Chlorpyrifos residues on carpet were substantially higher after broadcast applications than after aerosol applications, but residues on such nontarget surfaces as furniture were substantially higher for the aerosol application. This study indicates that human skin removes substantially less residue from carpets and furniture than either conventional wipe or PUF roller sampling methods following residential pest control applications of chlorpyrifos. Although this paper focuses on quantifying residue transfer from surface to skin using different surface sampling techniques, no attempt is made to quantify the amount of chlorpyrifos residue that is subsequently absorbed.  (+info)

Oral and dermal absorption of chlorpyrifos: a human volunteer study. (4/305)

OBJECTIVES: To determine the kinetics of elimination of urinary dialkylphosphate metabolites after oral and dermally applied doses of the organophosphate pesticide chlorpyrifos to human volunteers and to determine whether these doses affected plasma and erythrocyte cholinesterase activity. METHOD: Five volunteers ingested 1 mg (2852 nmol) of chlorpyrifos. Blood samples were taken over 24 hours and total void volumes of urine were collected over 100 hours. Four weeks later 28.59 mg (81567 nmol) of chlorpyrifos was administered dermally to each volunteer for 8 hours. Unabsorbed chlorpyrifos was washed from the skin and retained for subsequent measurement. The same blood and urine sampling regime was followed as for the oral administration. Plasma and erythrocyte cholinesterase concentrations were determined for each blood sample. The concentration of two urinary metabolites of chlorpyrifos--diethylphosphate and diethyl-thiophosphate--was determined for each urine sample. RESULTS: The apparent elimination half life of urinary dialkylphosphates after the oral dose was 15.5 hours and after the dermal dose it was 30 hours. Most of the oral dose (mean (range) 93% (55-115%)) and 1% of the applied dermal dose was recovered as urinary metabolites. About half (53%) of the dermal dose was recovered from the skin surface. The absorption rate through the skin, as measured by urinary metabolites was 456 ng/cm2/h. Blood plasma and erythrocyte cholinesterase activity did not fall significantly during either dosing regime. CONCLUSION: An oral dose of chlorpyrifos was readily absorbed through the skin and almost all of the dose was recovered as urinary dialkylphosphate metabolites. Excretion was delayed compared with the oral dose. Only a small proportion of the applied dose was recovered during the course of the experiment. The best time to collect urine samples for biological monitoring after dermal exposure is before the shift the next day. The amounts of chlorpyrifos used did not depress acetyl cholinesterase activity but could be readily detected as urinary dialkylphosphate metabolites indicating that the urinary assay is a more sensitive indicator of exposure.  (+info)

Pitfalls when determining tissue distributions of organophosphorus chemicals: sodium fluoride accelerates chemical degradation. (5/305)

This paper describes the tissue distributions of dichlorvos, an organophosphate, and chlorpyrifos-methyl, an organophosphorothioate, in a male individual who died after ingesting an insecticidal preparation containing these chemicals and the results of an in vitro stability study on dichlorvos and chlorpyrifos-methyl in blood and buffers. Tiny amounts of dichlorvos, 0.067 and 0.027 mg/L, were detected in the vitreous humor and cerebrospinal fluid, respectively. Although dichlorvos (0.082-8.99 mg/L or mg/kg) was detected in the thoracic aortic blood, thoracic inferior vena caval blood, pericardial fluid, bile, and spleen, it was strongly suggested that it had diffused postmortem from the stomach, which contained 879 mg, because no dichlorvos was detected in the other blood samples and tissues tested. Substantial amounts (0.615-4.15 mg/L) of chlorpyrifos-methyl were detected in all blood samples, and the order of its concentrations was as follows: pulmonary vessel blood > thoracic inferior vena caval blood > blood in the right cardiac chambers > blood in the left cardiac chambers approximately thoracic aortic blood > right femoral venous blood. The total amount of chlorpyrifos-methyl in the stomach was 612 mg. However, it was strongly suggested that virtually no chlorpyrifos-methyl diffused from the stomach into surrounding fluids and tissues postmortem because no chlorpyrifos-methyl was detected in the bile and little was found in the pericardial fluids. Neither compound was detected in the urine. In vitro experiments showed that dichlorvos (10 mg/L) almost disappeared from fresh (pH 7.4) and acidified (pH 6.2) blood samples within 24 and 72 h, respectively. However, 53 and 77% of the original amount of dichlorvos in 0.05M phosphate buffers at pH 7.4 and 6.2 were detected 72 h later. Chlorpyrifos-methyl (1 mg/L) was very stable in blood samples, regardless of the pH, during the 72-h study period, but in the pH 7.4 and 6.2 phosphate buffers, approximately 80% of the original amount had degraded after 72 h. These results indicate that organophosphates are degraded more rapidly by esterase activities than by chemical mechanisms and that organophosphorothioates are hydrolyzed chemically in aqueous solutions but are very stable in biological specimens and not metabolized by esterases. When sodium fluoride was added to blood samples, dichlorvos degraded completely within 15 min, and chlorpyrifos-methyl became very unstable. Thus, when analyzing samples to detect organophosphorus chemicals, this common preservative should not be added to fluid specimens.  (+info)

Changes in rat brain cholinesterase activity and muscarinic receptor density during and after repeated oral exposure to chlorpyrifos in early postnatal development. (6/305)

The effects of repeated oral exposures to the organophosphorus insecticide chlorpyrifos (CPS) on brain muscarinic receptor densities, together with cholinesterase (ChE) activity, were studied in early postnatal rats. Initially, the effects on esterases from lactational exposure to CPS were investigated in young rats by administering CPS (100, 150, or 200 mg/kg subcutaneously in corn oil) to dams 1 day postpartum, yielding a significant body burden of CPS in the dams for possible excretion in the milk. Brain ChE inhibition in pups was less severe than in dams, whereas liver carboxylesterase (CbxE) inhibition in pups was at the same level as in dams. Because of the limited brain ChE inhibition obtained following lactation, pups were exposed to CPS directly by gavage, using 3 dosing regimens to yield a dose response. The rats were gavaged with CPS in corn oil on alternate days from postnatal day (PND) 1 through PND 21. Rats in the low-dosage group received 11 treatments at 3 mg/kg, those in the medium-dosage group received 3 treatments at 3 mg/kg and 8 at 6 mg/kg, and those in the high dosage group received 3 treatments at 3 mg/kg, 4 at 6 mg/kg, and 4 at 12 mg/kg. ChE activity in brain homogenates were inhibited significantly by 29% and 63% in the low- and high-dosage groups, respectively, on PND 22 and by 17% in the high dosage group on PND 40. Muscarinic receptor densities in brain synaptosomes were reduced using 3H-N-methylscopolamine (NMS) and 3H-quinuclidinyl benzilate (QNB) as ligands, with the effects more prominent from 3H-NMS. Densities of both ligands recovered to the control level several days after terminating treatment. The results indicate that pups are apparently exposed to only limited amounts of chlorpyrifos and/or its oxon through the milk when dams are exposed to extremely high chlorpyrifos levels. In addition, repeated direct oral exposures of early postnatal rats to CPS will result in persistent brain ChE inhibition and will transiently reduce muscarinic receptor density.  (+info)

Gestational exposure to chlorpyrifos: dose response profiles for cholinesterase and carboxylesterase activity. (7/305)

This study investigates the in vivo dose response profiles of the target enzyme cholinesterase (ChE) and the detoxifying enzymes carboxylesterase (CaE) in the fetal and maternal compartments of pregnant rats dosed with chlorpyrifos [(O,O'-diethyl O-3,5,6-trichloro-2-pyridyl) phosphorothionate], a commonly used organophosphorus insecticide. Pregnant rats were dosed daily (po) with chlorpyrifos in corn oil (0, 3, 5, 7, or 10 mg/kg) on gestational days (GD) 14-18. Animals were sacrificed 5 h after the last chlorpyrifos dose (time of maximum brain cholinesterase inhibition) for analysis of ChE and CaE activity in maternal blood, liver, brain, placenta, and fetal liver and brain. The in vitro sensitivity (i.e., IC50, 30 min, 26 degrees C) of CaE also was determined by assaying the activity remaining after incubation with a range of chlorpyrifos-oxon concentrations. In vivo exposure to 10 mg/kg chlorpyrifos from GD14-18 caused overt maternal toxicity, with dose-related decreases in ChE activity more notable in maternal brain than fetal brain. Dose-related effects were also seen with chlorpyrifos-induced inhibition of fetal liver ChE and maternal brain CaE activities. Gestational exposure caused no inhibition of placental ChE or CaE, fetal brain CaE, or maternal blood CaE. ChE activities in the maternal blood and liver, as well as fetal and maternal liver CaE, however, were maximally inhibited by even the lowest dosage of chlorpyrifos. The in vitro sensitivity profiles of CaE to chlorpyrifos-oxon inhibition were valuable in predicting and verifying the in vivo CaE response profiles. Both the in vivo and in vitro findings indicated that fetal liver CaE inhibition was an extremely sensitive indicator of fetal chlorpyrifos exposure.  (+info)

Studies of toxicity of dermally-absorbed nurelle D 550 EC preparations. (8/305)

The aim of the study was the evaluation of the toxic effect of a two-component, preparation Nurelle D 550 EC (500 g of chlorpyrifos and 50 g cypermethrin per 1 l), administrated dermally. Toxicity was evaluated from histological and ultrastructural studies of the internal organs and immunotoxic effects (evaluation of phagocytical and bactericidal activity of neutrophils). The preparation for dermal application was applied in 2 concentrations (200 mg/kg/day of chlorpyrifos plus 20 mg/kg/day of cypermethrin or 1000 mg/kg/day of chlorpyrifos, plus 100 mg/kg/day of cypermethrin). The preparation was administrated on the tail skin of female Wistar rats for 4 hours daily for a period of 4 weeks. After 28 days of the experiment, the animals were anaesthetised and blood was taken from the heart to evaluate the granulocyte system. The following organs were taken for histological studies: liver, kidney, lung, heart, spleen, thymus and lymph nodes. Ultrastructural studies were carried out on the lung, liver, kidney and heart. The results of the study showed that dermal application of the pesticide Nurelle D 550 EC resulted in slight morphological and ultrastructural changes in the liver, kidney, lung and heart. The preparation examined slightly elevated the bactericidal activity of neutrophils. The differences, however, were not statistically significant. The phagocytic reaction in animals of both experimental groups did not differ from that observed in control group  (+info)

Chlorpyrifos is a type of pesticide that belongs to the class of organophosphates. It works by inhibiting the enzyme acetylcholinesterase, which leads to an accumulation of the neurotransmitter acetylcholine and causes toxic effects in insects. Chlorpyrifos is used to control a wide variety of pests, including insects that infest crops, homes, and gardens. It is also used to protect wood from termites and other wood-boring insects.

Chlorpyrifos can be harmful to humans if it is ingested, inhaled, or comes into contact with the skin. Exposure to chlorpyrifos can cause a range of symptoms, including nausea, vomiting, headache, dizziness, and muscle twitching. In severe cases, it can lead to respiratory failure, convulsions, and even death. Chlorpyrifos has been linked to developmental problems in children, including reduced IQ and attention deficit disorder. As a result, the use of chlorpyrifos in residential settings has been restricted in many countries.

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.

Diazinon is a type of organophosphate insecticide that works by inhibiting the enzyme acetylcholinesterase, which leads to an accumulation of the neurotransmitter acetylcholine in the synaptic cleft and results in overstimulation of cholinergic receptors. This can cause a variety of symptoms, including muscle twitching, tremors, convulsions, and respiratory failure, which can be fatal if not treated promptly.

Diazinon is used to control a wide range of insect pests in agriculture, horticulture, and residential settings. However, it is highly toxic to both insects and mammals, including humans, and its use is regulated by environmental and public health agencies around the world. Exposure to diazinon can occur through inhalation, skin contact, or ingestion, and can cause acute and chronic health effects depending on the level and duration of exposure.

In the medical field, diazinon poisoning is treated with atropine, which blocks the action of acetylcholine at muscarinic receptors, and oximes, which reactivate acetylcholinesterase. Supportive care, such as oxygen therapy, mechanical ventilation, and fluid replacement, may also be necessary in severe cases.

Cholinesterase inhibitors are a class of drugs that work by blocking the action of cholinesterase, an enzyme that breaks down the neurotransmitter acetylcholine in the body. By inhibiting this enzyme, the levels of acetylcholine in the brain increase, which can help to improve symptoms of cognitive decline and memory loss associated with conditions such as Alzheimer's disease and other forms of dementia.

Cholinesterase inhibitors are also used to treat other medical conditions, including myasthenia gravis, a neuromuscular disorder that causes muscle weakness, and glaucoma, a condition that affects the optic nerve and can lead to vision loss. Some examples of cholinesterase inhibitors include donepezil (Aricept), galantamine (Razadyne), and rivastigmine (Exelon).

It's important to note that while cholinesterase inhibitors can help to improve symptoms in some people with dementia, they do not cure the underlying condition or stop its progression. Side effects of these drugs may include nausea, vomiting, diarrhea, and increased salivation. In rare cases, they may also cause seizures, fainting, or cardiac arrhythmias.

Pyridones are a class of organic compounds that contain a pyridone ring, which is a heterocyclic ring consisting of a six-membered ring with five carbon atoms and one nitrogen atom, with one oxygen atom attached to the nitrogen atom by a double bond. Pyridones can be found in various natural sources, including plants and microorganisms, and they also have important applications in the pharmaceutical industry as building blocks for drug design and synthesis. Some drugs that contain pyridone rings include antihistamines, anti-inflammatory agents, and antiviral agents.

Cholinesterases are a group of enzymes that play an essential role in the nervous system by regulating the transmission of nerve impulses. They work by breaking down a type of chemical messenger called acetylcholine, which is released by nerves to transmit signals to other nerves or muscles.

There are two main types of cholinesterases: acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). AChE is found primarily in the nervous system, where it rapidly breaks down acetylcholine to terminate nerve impulses. BChE, on the other hand, is found in various tissues throughout the body, including the liver and plasma, and plays a less specific role in breaking down various substances, including some drugs and toxins.

Inhibition of cholinesterases can lead to an accumulation of acetylcholine in the synaptic cleft, which can result in excessive stimulation of nerve impulses and muscle contractions. This effect is exploited by certain medications used to treat conditions such as myasthenia gravis, Alzheimer's disease, and glaucoma, but can also be caused by exposure to certain chemicals or toxins, such as organophosphate pesticides and nerve agents.

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.

Parathion is not a medical term, but a chemical one. It refers to a type of organophosphate insecticide that is highly toxic and can be absorbed through the skin or ingested. Parathion works by inhibiting an enzyme called acetylcholinesterase, which leads to an overstimulation of the nervous system and can cause symptoms such as muscle twitching, convulsions, respiratory failure, and death. Although parathion is not used in medical treatments, it is important for healthcare providers to be aware of its potential health effects, particularly in cases of accidental or intentional exposure.

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.

I'm sorry for any confusion, but "pest control" is not a term typically used in medical definitions. Pest control refers to the regulation or management of species considered to be pests, which can include insects, rodents, and other organisms that can cause damage to crops, transmit diseases, or otherwise negatively impact human activities.

In a medical context, you might be looking for information on "pesticide exposure" or "insect-borne diseases." Pesticide exposure refers to the contact with pesticides, which are substances used to control pests. These exposures can occur through inhalation, ingestion, or skin contact and may lead to a variety of health effects depending on the type and amount of pesticide involved. Insect-borne diseases are illnesses transmitted to humans through the bite of infected insects, such as mosquitoes, ticks, or fleas. Examples include malaria, Lyme disease, and Zika virus infection.

Acetylcholinesterase (AChE) is an enzyme that catalyzes the hydrolysis of acetylcholine (ACh), a neurotransmitter, into choline and acetic acid. This enzyme plays a crucial role in regulating the transmission of nerve impulses across the synapse, the junction between two neurons or between a neuron and a muscle fiber.

Acetylcholinesterase is located in the synaptic cleft, the narrow gap between the presynaptic and postsynaptic membranes. When ACh is released from the presynaptic membrane and binds to receptors on the postsynaptic membrane, it triggers a response in the target cell. Acetylcholinesterase rapidly breaks down ACh, terminating its action and allowing for rapid cycling of neurotransmission.

Inhibition of acetylcholinesterase leads to an accumulation of ACh in the synaptic cleft, prolonging its effects on the postsynaptic membrane. This can result in excessive stimulation of cholinergic receptors and overactivation of the cholinergic system, which may cause a range of symptoms, including muscle weakness, fasciculations, sweating, salivation, lacrimation, urination, defecation, bradycardia, and bronchoconstriction.

Acetylcholinesterase inhibitors are used in the treatment of various medical conditions, such as Alzheimer's disease, myasthenia gravis, and glaucoma. However, they can also be used as chemical weapons, such as nerve agents, due to their ability to disrupt the nervous system and cause severe toxicity.

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.

Neurotoxicity syndromes refer to a group of conditions caused by exposure to neurotoxins, which are substances that can damage the structure or function of the nervous system. Neurotoxicity syndromes can affect both the central and peripheral nervous systems and may cause a wide range of symptoms depending on the type and severity of the exposure.

Symptoms of neurotoxicity syndromes may include:

* Headache
* Dizziness
* Tremors or shaking
* Difficulty with coordination or balance
* Numbness or tingling in the hands and feet
* Vision problems
* Memory loss or difficulty concentrating
* Seizures or convulsions
* Mood changes, such as depression or anxiety

Neurotoxicity syndromes can be caused by exposure to a variety of substances, including heavy metals (such as lead, mercury, and arsenic), pesticides, solvents, and certain medications. In some cases, neurotoxicity syndromes may be reversible with treatment, while in other cases, the damage may be permanent.

Prevention is key in avoiding neurotoxicity syndromes, and it is important to follow safety guidelines when working with or around potential neurotoxins. If exposure does occur, prompt medical attention is necessary to minimize the risk of long-term health effects.

Paraoxon is the active metabolite of the organophosphate insecticide parathion. It functions as an acetylcholinesterase inhibitor, which means it prevents the breakdown of the neurotransmitter acetylcholine in the synaptic cleft. This leads to an accumulation of acetylcholine and overstimulation of cholinergic receptors, causing a variety of symptoms such as muscle weakness, increased salivation, sweating, lacrimation, nausea, vomiting, and potentially fatal respiratory failure.

Paraoxon is also used in research and diagnostic settings to measure acetylcholinesterase activity. It can be used to determine the degree of inhibition of this enzyme by various chemicals or toxins, including other organophosphate compounds.

Organophosphates are a group of chemicals that include insecticides, herbicides, and nerve gases. They work by inhibiting an enzyme called acetylcholinesterase, which normally breaks down the neurotransmitter acetylcholine in the synapse between nerves. This leads to an overaccumulation of acetylcholine, causing overstimulation of the nervous system and resulting in a wide range of symptoms such as muscle twitching, nausea, vomiting, diarrhea, sweating, confusion, and potentially death due to respiratory failure. Organophosphates are highly toxic and their use is regulated due to the risks they pose to human health and the environment.

Butyrylcholinesterase (BChE) is an enzyme that catalyzes the hydrolysis of esters of choline, including butyrylcholine and acetylcholine. It is found in various tissues throughout the body, including the liver, brain, and plasma. BChE plays a role in the metabolism of certain drugs and neurotransmitters, and its activity can be inhibited by certain chemicals, such as organophosphate pesticides and nerve agents. Elevated levels of BChE have been found in some neurological disorders, while decreased levels have been associated with genetic deficiencies and liver disease.

Carbaryl is a carbamate pesticide that is used to control a wide variety of insects, including fleas, ticks, and mosquitoes. It works by inhibiting the action of an enzyme called cholinesterase, which is necessary for the proper functioning of the nervous system in insects. This leads to paralysis and death of the pests. Carbaryl is also used in some veterinary products to treat parasitic infestations. It can be found in various forms, such as powders, granules, and solutions, and can be applied to plants, animals, and indoor/outdoor surfaces. However, it can be harmful to non-target organisms, including humans, if not used properly. Therefore, it is important to follow the label instructions carefully when using carbaryl products.

Organophosphate (OP) poisoning refers to the toxic effects that occur after exposure to organophosphate compounds, which are commonly used as pesticides, nerve agents, and plasticizers. These substances work by irreversibly inhibiting acetylcholinesterase, an enzyme that breaks down the neurotransmitter acetylcholine in the nervous system. As a result, excessive accumulation of acetylcholine leads to overstimulation of cholinergic receptors, causing a wide range of symptoms.

The severity and type of symptoms depend on the dose, duration, and route of exposure (inhalation, ingestion, or skin absorption). The primary manifestations of organophosphate poisoning are:

1. Muscarinic effects: Excess acetylcholine at muscarinic receptors in the parasympathetic nervous system results in symptoms such as narrowed pupils (miosis), increased salivation, lacrimation, sweating, bronchorrhea (excessive respiratory secretions), diarrhea, bradycardia (decreased heart rate), and hypotension.
2. Nicotinic effects: Overstimulation of nicotinic receptors at the neuromuscular junction leads to muscle fasciculations, weakness, and paralysis. This can also cause tachycardia (increased heart rate) and hypertension.
3. Central nervous system effects: OP poisoning may result in headache, dizziness, confusion, seizures, coma, and respiratory depression.

Treatment for organophosphate poisoning includes decontamination, supportive care, and administration of antidotes such as atropine (to block muscarinic effects) and pralidoxime (to reactivate acetylcholinesterase). Delayed treatment can lead to long-term neurological damage or even death.

Carboxylesterase is a type of enzyme that catalyzes the hydrolysis of ester bonds in carboxylic acid esters, producing alcohol and carboxylate products. These enzymes are widely distributed in various tissues, including the liver, intestines, and plasma. They play important roles in detoxification, metabolism, and the breakdown of xenobiotics (foreign substances) in the body.

Carboxylesterases can also catalyze the reverse reaction, forming esters from alcohols and carboxylates, which is known as transesterification or esterification. This activity has applications in industrial processes and biotechnology.

There are several families of carboxylesterases, with different substrate specificities, kinetic properties, and tissue distributions. These enzymes have been studied for their potential use in therapeutics, diagnostics, and drug delivery systems.

Acetylthiocholine is a synthetic chemical compound that is widely used in scientific research, particularly in the field of neuroscience. It is the acetylated form of thiocholine, which is a choline ester. Acetylthiocholine is often used as a substrate for enzymes called cholinesterases, including acetylcholinesterase (AChE) and butyrylcholinesterase (BChE).

When Acetylthiocholine is hydrolyzed by AChE, it produces choline and thioacetic acid. This reaction is important because it terminates the signal transduction of the neurotransmitter acetylcholine at the synapse between neurons. Inhibition of AChE can lead to an accumulation of Acetylthiocholine and acetylcholine, which can have various effects on the nervous system, depending on the dose and duration of inhibition.

Acetylthiocholine is also used as a reagent in the Ellman's assay, a colorimetric method for measuring AChE activity. In this assay, Acetylthiocholine is hydrolyzed by AChE, releasing thiocholine, which then reacts with dithiobisnitrobenzoic acid (DTNB) to produce a yellow color. The intensity of the color is proportional to the amount of thiocholine produced and can be used to quantify AChE activity.

Methyl parathion is an organophosphate insecticide and acaricide. It functions by inhibiting the enzyme cholinesterase, which leads to an accumulation of the neurotransmitter acetylcholine, causing nervous system excitation and ultimately damage or death in insects. However, it can also have toxic effects on mammals, including humans, if ingested, inhaled, or absorbed through the skin. It is classified as a highly hazardous pesticide by the World Health Organization (WHO) and its use is restricted or banned in many countries due to its high toxicity and environmental persistence.

Herbicides are a type of pesticide used to control or kill unwanted plants, also known as weeds. They work by interfering with the growth processes of the plant, such as inhibiting photosynthesis, disrupting cell division, or preventing the plant from producing certain essential proteins.

Herbicides can be classified based on their mode of action, chemical composition, and the timing of their application. Some herbicides are selective, meaning they target specific types of weeds while leaving crops unharmed, while others are non-selective and will kill any plant they come into contact with.

It's important to use herbicides responsibly and according to the manufacturer's instructions, as they can have negative impacts on the environment and human health if not used properly.

I'm sorry for any confusion, but "Portraits as Topic" is not a medical term or concept. It refers to portraits, which are visual representations or images of a person, usually showing the face and shoulders. The term "as Topic" indicates that it is the subject or theme being discussed. Therefore, "Portraits as Topic" generally relates to the study, analysis, or discussion of portraits in various contexts, such as art, psychology, sociology, or history. If you have any medical questions or terms you would like me to define, please don't hesitate to ask!

I'm sorry for any confusion, but "Interior Design and Furnishings" is not a term that has a medical definition. Interior design refers to the planning, designing, and coordinating of spaces in residential, commercial, or industrial buildings to create functional and aesthetically pleasing environments. This can include selecting colors, furniture, lighting, flooring, and other decorative materials. Furnishings generally refer to the items such as furniture, curtains, rugs, and other decorative elements that are used to make a space comfortable and attractive.

If you have any questions related to medical topics or definitions, I would be happy to try to help answer them for you!

Organophosphorus compounds are a class of chemical substances that contain phosphorus bonded to organic compounds. They are used in various applications, including as plasticizers, flame retardants, pesticides (insecticides, herbicides, and nerve gases), and solvents. In medicine, they are also used in the treatment of certain conditions such as glaucoma. However, organophosphorus compounds can be toxic to humans and animals, particularly those that affect the nervous system by inhibiting acetylcholinesterase, an enzyme that breaks down the neurotransmitter acetylcholine. Exposure to these compounds can cause symptoms such as nausea, vomiting, muscle weakness, and in severe cases, respiratory failure and death.

"Salix" is the genus name for a group of plants commonly known as willows. These are deciduous trees and shrubs that belong to the family Salicaceae. While "Salix" is not a medical term itself, certain species of willow have been used in medicine for their medicinal properties.

For instance, the bark of white willow (Salix alba) contains salicin, which has anti-inflammatory and analgesic effects similar to aspirin. The use of willow bark extract as a natural pain reliever and fever reducer dates back thousands of years in various traditional medicine systems.

However, it's important to note that the modern medical definition of "salicylate" refers to a group of compounds that includes both naturally occurring substances like salicin found in willow bark and synthetic derivatives such as aspirin (acetylsalicylic acid). These compounds share similar therapeutic properties and are used to treat pain, inflammation, and fever.

I apologize for any confusion, but "agriculture" is not a term that has a medical definition. Agriculture refers to the cultivation and breeding of animals, plants, and fungi for food, fiber, biofuel, medicinal plants, and other products used to sustain and enhance human life. It is an important industry and practice that has been developed over thousands of years and continues to play a critical role in global food production and security.

Pyrethrins are a group of naturally occurring organic compounds extracted from the flowers of Chrysanthemum cinerariaefolium and Chrysanthemum coccineum. They have been used for centuries as insecticides due to their ability to disrupt the nervous system of insects, leading to paralysis and death. Pyrethrins are composed of six esters, pyrethrin I and II, cinerin I and II, and jasmolin I and II, which have different insecticidal properties but share a similar mode of action. They are commonly used in household insect sprays, pet shampoos, and agricultural applications to control a wide range of pests. However, pyrethrins can be toxic to fish and some beneficial insects, so they must be used with caution.

Fenthion is a type of pesticide called an organophosphate insecticide. It works by inhibiting the enzyme cholinesterase, which leads to an accumulation of acetylcholine and ultimately results in nervous system dysfunction in insects. Fenthion can be used to control a variety of pests, including flies, mosquitoes, and ticks. However, it is also toxic to non-target organisms, including humans, and has been linked to various health effects such as neurological damage and cancer. As a result, the use of fenthion has been restricted or banned in many countries.

'Cladosporium' is a genus of fungi that are widely distributed in the environment, particularly in soil, decaying plant material, and indoor air. These fungi are known for their dark-pigmented spores, which can be found in various shapes and sizes depending on the species. They are important causes of allergies and respiratory symptoms in humans, as well as plant diseases. Some species of Cladosporium can also produce toxins that may cause health problems in susceptible individuals. It is important to note that medical definitions typically refer to specific diseases or conditions that affect human health, so 'Cladosporium' itself would not be considered a medical definition.

Tetraisopropylpyrophosphamide (TIPP) is not typically considered a medical compound, but rather a chemical reagent used in laboratory settings for various research purposes. However, I can provide a general chemical definition for you:

Tetraisopropylpyrophosphamide (C12H28N2O4P) is an organophosphorus compound with the molecular formula [(i-Pr)2P(O)]2. It is a colorless liquid that is used as a reagent in organic synthesis, particularly for the preparation of phosphate esters and other organophosphorus compounds.

It's important to note that TIPP is highly toxic and should be handled with appropriate precautions in a laboratory setting. It can cause skin and eye irritation, respiratory problems, and may be harmful if swallowed or inhaled. Therefore, it is not used in medical treatments or therapies for patients.

Tritolyl phosphates are not a medical term, but rather a class of industrial chemicals. They are organophosphate esters made from the reaction of toluene with phosphoric acid. These chemicals have various uses, including as plasticizers, flame retardants, and hydraulic fluids.

Exposure to high levels of tritolyl phosphates can cause irritation to the skin, eyes, and respiratory tract. However, they are not typically considered a significant health concern at the low levels encountered in most occupational or environmental settings. There is no known medical condition specifically associated with "tritolyl phosphates."

Threshold Limit Values (TLVs) are defined by the American Conference of Governmental Industrial Hygienists (ACGIH) as "airborne concentrations of substances and physical agents to which most workers can be exposed day after day for a normal 8-hour workday and 40-hour workweek, without adverse health effects." TLVs are based on available scientific data and are designed to provide guidance to occupational health professionals in making decisions regarding safe levels of exposure to various workplace hazards.

TLVs are divided into three categories:

1. Time-weighted average (TWA): This is the average airborne concentration of a substance or physical agent to which a worker can be exposed for an 8-hour workday and 40-hour workweek, without experiencing adverse health effects.
2. Short-term exposure limit (STEL): This is the maximum concentration of a substance or physical agent to which a worker can be exposed for a short period of time (usually 15 minutes) without experiencing significant irritation, narcosis, or other acute toxic effects. STELs are intended to protect workers from brief, but potentially hazardous, exposures.
3. Ceiling limit (CL): This is the concentration of a substance or physical agent that should not be exceeded at any time during the workday. Ceiling limits are designed to protect workers from the potential acute effects of high-concentration exposures.

It's important to note that TLVs are guidelines and not regulatory standards, meaning they do not have the force of law. However, many organizations and companies use TLVs as a basis for establishing their own exposure limits and workplace safety policies.

Malathion is a type of organophosphate pesticide that is widely used in agriculture, public health, and residential settings for the control of various insect pests. It works by inhibiting an enzyme called acetylcholinesterase, which leads to the accumulation of the neurotransmitter acetylcholine in the synapses, resulting in overstimulation of the nervous system and ultimately death of the insect.

In a medical context, malathion is also used as a topical treatment for head lice infestations. It is available in various forms, such as shampoos, lotions, and sprays, and works by killing the lice and their eggs on contact. However, it is important to follow the instructions carefully when using malathion products to avoid excessive exposure and potential health risks.

Environmental exposure refers to the contact of an individual with any chemical, physical, or biological agent in the environment that can cause a harmful effect on health. These exposures can occur through various pathways such as inhalation, ingestion, or skin contact. Examples of environmental exposures include air pollution, water contamination, occupational chemicals, and allergens. The duration and level of exposure, as well as the susceptibility of the individual, can all contribute to the risk of developing an adverse health effect.

No FAQ available that match "chlorpyrifos"

No images available that match "chlorpyrifos"