Paraquat

Smith, Paul; Heath, Donald; Fishman, Alfred P.

doi:10.1080/10408447609164020

Cited by 200 publications

(78 citation statements)

References 73 publications

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“…In experimental animals or humans who develop an extensive alveolitis but do not succumb during the first few days of poisoning, a fibrosis develops that can be so severe as to destroy the normal architecture of the lung and lead to death from anoxia (6). This fibrosis can be regarded as a consequence of the acute destructive phase and is probably part of the normal reparative response of the lung.…”

Section: Introductionmentioning

confidence: 99%

“…The first is a destructive phase in which the alveolar type I and Type II epithelial cells are damaged within a few days of poisoning (6). If this damage is extensive, an alveolitis develops and is associated with frank hemorrhage, edema, and the infiltration of inflammatory cells into the interstitial and alveolar spaces of the lung.…”

Section: Introductionmentioning

confidence: 99%

“…The second phase of the lung lesion is characterized by an extensive proliferative fibrosis (6). In experimental animals or humans who develop an extensive alveolitis but do not succumb during the first few days of poisoning, a fibrosis develops that can be so severe as to destroy the normal architecture of the lung and lead to death from anoxia (6).…”

Section: Introductionmentioning

confidence: 99%

“…There are two distinct phases in the development of lung lesions provoked by paraquat (6). The first is a destructive phase in which the alveolar type I and Type II epithelial cells are damaged within a few days of poisoning (6).…”

Section: Introductionmentioning

confidence: 99%

“…When paraquat is given to experimental animals (e.g., the rat), many will die within the first few days of dosing as a consequence of this alveolitis. Although there have been occasional reports of endothelial cell damage in the lung, it is generally accepted that the primary target cells of paraquat are those of the alveolar epithelium (6).…”

Section: Introductionmentioning

confidence: 99%

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The Importance of Epithelial Uptake Systems in Lung Toxicity

Smith¹,

Lewis²,

Wyatt³

et al. 1990

Environmental Health Perspectives

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The discovery that the herbicide paraquat was selectively accumulated by the lung, both in vivo and in vitro, in comparison with other tissues, provided an explanation for its selective toxicity to the lung. This uptake process is energy dependent and obeys saturation kinetics. A characterization ofthe process led to the identification of endogenous chemicals that are the natural substrates for the system. Among these are a series of diamines and polyamines, as well as the diaminodisulfide cystamine. It appears that paraquat, because of specific structural similarities to these endogenous polyamines, is mistakenly accumulated by the lung. This uptake process is specifically located in the alveolar Type II cell, the Clara cell, and probably the alveolar Type I cell.With the development of knowledge of the structural requirements of chemicals to be accumulated by this system, it is possible to predict which chemicals will be accumulated by the lung or design molecules that are targeted to the alveolar epithelial and Clara cells.In the wider perspective, this polyamine uptake system has been found on a number of cancerous cells or tissues. With the knowledge of the uptake system in the lung, it should be possible to design drugs that will be specifically concentrated in cells that possess this system. IntroductionBecause the lung is responsible for all gas exchange necessary for oxidative metabolism, it is inevitably exposed to toxic gases, vapors, and particles (if small enough) present in the atmosphere. The respiratory function of the lung requires a large surface area (in man, about the size of a tennis court) that, on the air side, is covered by epithelial cells intimately associated with an extensive capillary network. Apart from inhalation, the lung is also exposed to toxic compounds that have been absorbed into the bloodstream or are in the form of metabolites, formed either in the lung or in extrapulmonary tissue.In order to meet its respiratory function, the lung requires numerous cell types. More than 40 cell types have been identified in the lung (1); these are required to provide the diverse architecture associated with cartilage, smooth muscle, connective tissue, submucosal glands, the vascular system, and the respiratory unit (alveoli)

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The Importance of Epithelial Uptake Systems in Lung Toxicity

Smith¹,

Lewis²,

Wyatt³

et al. 1990

Environmental Health Perspectives

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Nephrotoxicity of Paraquat in Man

Nd¹,

Rl²,

Rd³

et al. 1979

Arch Intern Med

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Herbicides

Francesca,

Tosti,

Wilks

et al. 2023

Patty's Toxicology

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Herbicides are used in agriculture to eliminate weeds that would otherwise damage the crop of interest or to provide practical advantages in facilitating the harvesting of crops (e.g., glyphosate on cereals). They are also used in areas of public interest (e.g., railways, public and private gardens, or lawns). Their phytotoxic action occurs either on the site of contact or following absorption by the plant and systemic translocation to other organs. Postemergence herbicides are applied on developed undesired weeds, while preemergence herbicides are typically applied on the ground soon after seeding of the desired culture to prevent weed's development. Herbicides have different selectivity for plants. The amount of global herbicide use has been increasing over the years, from approximately of 600,000 tonnes in 1990 to more than 1,200,000 tonnes yearly since 2011. When herbicides are applied downward, human exposure during their application may be less than that following the application of insecticides or fungicides. Exposure can quantitatively change if the application is performed by handheld or by vehicle, with the latter generally reporting a lower exposure. In addition, since herbicides exert their pesticidal mode of action on metabolic processes that are generally unique to plants, they are, in principle, of low toxicity in mammals with the notable exception of paraquat. Some herbicides were reported to have irritating properties. Formulated products may contain adjuvants (stabilizers, penetrants, surfactants, dispersants) that could have, alone or in combination, more severe toxicity or irritating properties than the active herbicide alone.

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Paraquat

Cited by 200 publications

References 73 publications

The Importance of Epithelial Uptake Systems in Lung Toxicity

The Importance of Epithelial Uptake Systems in Lung Toxicity

Nephrotoxicity of Paraquat in Man

Herbicides

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