Amitrole: A non-selective post-emergence, translocated herbicide. According to the Seventh Annual Report on Carcinogens (PB95-109781, 1994) this substance may reasonably be anticipated to be a carcinogen. (From Merck Index, 12th ed) It is an irreversible inhibitor of CATALASE, and thus impairs activity of peroxisomes.Pesticide Residues: Pesticides or their breakdown products remaining in the environment following their normal use or accidental contamination.Lethal Dose 50: The dose amount of poisonous or toxic substance or dose of ionizing radiation required to kill 50% of the tested population.Carbonates: Salts or ions of the theoretical carbonic acid, containing the radical CO2(3-). Carbonates are readily decomposed by acids. The carbonates of the alkali metals are water-soluble; all others are insoluble. (From Grant & Hackh's Chemical Dictionary, 5th ed)Toxicity Tests, Acute: Experiments designed to determine the potential toxic effects of one-time, short-term exposure to a chemical or chemicals.Sodium Bicarbonate: A white, crystalline powder that is commonly used as a pH buffering agent, an electrolyte replenisher, systemic alkalizer and in topical cleansing solutions.Pesticides: Chemicals used to destroy pests of any sort. The concept includes fungicides (FUNGICIDES, INDUSTRIAL); INSECTICIDES; RODENTICIDES; etc.United States Indian Health Service: A division of the UNITED STATES PUBLIC HEALTH SERVICE that is responsible for the public health and the provision of medical services to NATIVE AMERICANS in the United States, primarily those residing on reservation lands.AlaskaIndians, North American: Individual members of North American ethnic groups with ancient historic ancestral origins in Asia.Inuits: Inuktitut-speakers generally associated with the northern polar region.Federal Government: The level of governmental organization and function at the national or country-wide level.Health Services, Indigenous: Health care provided to specific cultural or tribal peoples which incorporates local customs, beliefs, and taboos.United StatesMaximum Allowable Concentration: The maximum exposure to a biologically active physical or chemical agent that is allowed during an 8-hour period (a workday) in a population of workers, or during a 24-hour period in the general population, which does not appear to cause appreciable harm, whether immediate or delayed for any period, in the target population. (From Lewis Dictionary of Toxicology, 1st ed)Occupational Exposure: The exposure to potentially harmful chemical, physical, or biological agents that occurs as a result of one's occupation.Air Pollutants, Occupational: Air pollutants found in the work area. They are usually produced by the specific nature of the occupation.Workplace: Place or physical location of work or employment.Hazardous Substances: Elements, compounds, mixtures, or solutions that are considered severely harmful to human health and the environment. They include substances that are toxic, corrosive, flammable, or explosive.Occupational Diseases: Diseases caused by factors involved in one's employment.Asthma, Occupational: Asthma attacks caused, triggered, or exacerbated by OCCUPATIONAL EXPOSURE.2H-Benzo(a)quinolizin-2-ol, 2-Ethyl-1,3,4,6,7,11b-hexahydro-3-isobutyl-9,10-dimethoxy-: Proposed catecholamine depletor.WashingtonFlatfishes: Common name for the order Pleuronectiformes. A very distinctive group in that during development they become asymmetrical, i.e., one eye migrates to lie adjacent to the other. They swim on the eyeless side. FLOUNDER, sole, and turbot, along with several others, are included in this order.Oncorhynchus kisutch: An anadromous species of SALMON ranging from the Arctic and Pacific Oceans to Monterey Bay, California and inhabiting ocean and coastal streams. It is familiarly known as the coho or silver salmon. It is relatively small but its light-colored flesh is of good flavor.Pacific OceanSound: A type of non-ionizing radiation in which energy is transmitted through solid, liquid, or gas as compression waves. Sound (acoustic or sonic) radiation with frequencies above the audible range is classified as ultrasonic. Sound radiation below the audible range is classified as infrasonic.Water Pollutants, Chemical: Chemical compounds which pollute the water of rivers, streams, lakes, the sea, reservoirs, or other bodies of water.Lolium: Common member of the Gramineae family used as cattle FODDER. It harbors several fungi and other parasites toxic to livestock and people and produces allergenic compounds, especially in its pollen. The most commonly seen varieties are L. perenne, L. multiflorum, and L. rigidum.Herbicide Resistance: Diminished or failed response of PLANTS to HERBICIDES.Herbicides: Pesticides used to destroy unwanted vegetation, especially various types of weeds, grasses (POACEAE), and woody plants. Some plants develop HERBICIDE RESISTANCE.Acetolactate Synthase: A flavoprotein enzyme that catalyzes the formation of acetolactate from 2 moles of PYRUVATE in the biosynthesis of VALINE and the formation of acetohydroxybutyrate from pyruvate and alpha-ketobutyrate in the biosynthesis of ISOLEUCINE. This enzyme was formerly listed as EC A genus in the family Myrtaceae sometimes known as "stoppers" in FOLK MEDICINE. Many species of the genus SYZYGIUM have synonymous names that begin with the Eugenia genus name.Triazines: Heterocyclic rings containing three nitrogen atoms, commonly in 1,2,4 or 1,3,5 or 2,4,6 formats. Some are used as HERBICIDES.GreeceCirsium: A plant genus of the family ASTERACEAE. Members contain pectolinarin (a flavonoid glycoside).Weevils: BEETLES in the family Curculionidae and the largest family in the order COLEOPTERA. They have a markedly convex shape and many are considered pests.Milk Thistle: The plant Silybum marianum in the family ASTERACEAE containing the bioflavonoid complex SILYMARIN. For centuries this has been used traditionally to treat liver disease. Silybum marianum (L.) Gaertn. = Carduus marianus L.Seasons: Divisions of the year according to some regularly recurrent phenomena usually astronomical or climatic. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Plant Leaves: Expanded structures, usually green, of vascular plants, characteristically consisting of a bladelike expansion attached to a stem, and functioning as the principal organ of photosynthesis and transpiration. (American Heritage Dictionary, 2d ed)Oviposition: The process of laying or shedding fully developed eggs (OVA) from the female body. The term is usually used for certain INSECTS or FISHES with an organ called ovipositor where eggs are stored or deposited before expulsion from the body.Water Pollutants: Substances or organisms which pollute the water or bodies of water. Use for water pollutants in general or those for which there is no specific heading.Spectrophotometry, Ultraviolet: Determination of the spectra of ultraviolet absorption by specific molecules in gases or liquids, for example Cl2, SO2, NO2, CS2, ozone, mercury vapor, and various unsaturated compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Environmental Pollutants: Substances or energies, for example heat or light, which when introduced into the air, water, or land threaten life or health of individuals or ECOSYSTEMS.Polycyclic Hydrocarbons, Aromatic: A major group of unsaturated cyclic hydrocarbons containing two or more rings. The vast number of compounds of this important group, derived chiefly from petroleum and coal tar, are rather highly reactive and chemically versatile. The name is due to the strong and not unpleasant odor characteristic of most substances of this nature. (From Hawley's Condensed Chemical Dictionary, 12th ed, p96)Air Pollutants: Any substance in the air which could, if present in high enough concentration, harm humans, animals, vegetation or material. Substances include GASES; PARTICULATE MATTER; and volatile ORGANIC CHEMICALS.Databases, Factual: Extensive collections, reputedly complete, of facts and data garnered from material of a specialized subject area and made available for analysis and application. The collection can be automated by various contemporary methods for retrieval. The concept should be differentiated from DATABASES, BIBLIOGRAPHIC which is restricted to collections of bibliographic references.Hair Preparations: Hair grooming, cleansing and modifying products meant for topical application to hair, usually human. They include sprays, bleaches, dyes, conditioners, rinses, shampoos, nutrient lotions, etc.Petroleum: Naturally occurring complex liquid hydrocarbons which, after distillation, yield combustible fuels, petrochemicals, and lubricants.Carcinogens: Substances that increase the risk of NEOPLASMS in humans or animals. Both genotoxic chemicals, which affect DNA directly, and nongenotoxic chemicals, which induce neoplasms by other mechanism, are included.Clothing: Fabric or other material used to cover the body.Interior Design and Furnishings: The planning of the furnishings and decorations of an architectural interior.BooksLice Infestations: Parasitic attack or subsistence on the skin by members of the order Phthiraptera, especially on humans by Pediculus humanus of the family Pediculidae. The hair of the head, eyelashes, and pubis is a frequent site of infestation. (From Dorland, 28th ed; Stedman, 26th ed)

Role of antioxidant defenses against ethanol-induced damage in cultured rat gastric epithelial cells. (1/160)

Reactive oxygen species appears to be involved in the pathogenesis of ethanol-induced gastric mucosal injury in vivo. Because ingested ethanol diffuses into the gastric mucosa, targeting both epithelium and endothelium, in the present study we examined the possible protective effect of antioxidants on ethanol damage in gastric epithelial cells and endothelial cells in vitro. Cytotoxicity by ethanol was quantified by measuring 51Cr release. The effects of impairment of the glutathione redox cycle and of inhibition of cellular catalase were examined. The generation of superoxide was assessed by the reduction in cytochrome c. Ethanol caused a time- and dose-dependent increase in 51Cr release from epithelial cells. Incubation of cells with DL-buthionine-(S,R)-sulfoximine, while reducing glutathione production, dose dependently enhanced ethanol-induced injury. 1,3-Bis(chloroethyl)-nitrosourea, while inhibiting glutathione reductase activity, also sensitized cells to ethanol. In contrast, the inhibition of catalase with 3-amino-1,2, 4-triazole did not alter the susceptibility of epithelial cells to ethanol. Ethanol induced damage to endothelial cells in a similar fashion. In endothelial cells, however, neither impairment of the glutathione cycle nor inhibition of catalase influenced ethanol-induced damage. Epithelial cells, when exposed to ethanol, increased superoxide production as a function of ethanol concentration, whereas endothelial cells did not. The glutathione redox cycle, but not cellular catalase, plays a critical role in protecting epithelial cells against ethanol damage, whereas neither antioxidant seems to play a role in protection of endothelial cells. The distinct difference in antioxidant protection against ethanol appears to depend on the capability of each cell to produce cytotoxic oxygen species in response to ethanol exposure.  (+info)

Reactive oxygen species participate in mdr1b mRNA and P-glycoprotein overexpression in primary rat hepatocyte cultures. (2/160)

P-glycoproteins encoded by multidrug resistance type 1 (mdr1) genes mediate ATP-dependent efflux of numerous lipophilic xenobiotics, including several anticancer drugs, from cells. Overexpression of mdr1-type transporters in tumour cells contributes to a multidrug resistance phenotype. Several factors shown to induce mdr1 overexpression (UV irradiation, epidermal growth factor, tumour necrosis factor alpha, doxorubicin) have been associated with the generation of reactive oxygen species (ROS). In the present study, primary rat hepatocyte cultures that exhibit time-dependent overexpression of the mdr1b gene were used as a model system to investigate whether ROS might participate in the regulation of intrinsic mdr1b overexpression. Addition of H2O2 to the culture medium resulted in a significant increase in mdrlb mRNA and P-glycoprotein after 3 days of culture, with maximal (approximately 2-fold) induction being observed with 0.5-1 mM H2O2. Furthermore, H2O2 led to activation of poly(ADP-ribose) polymerase, a nuclear enzyme activated by DNA strand breaks, indicating that ROS reached the nuclear compartment. Thus, extracellularly applied H2O2 elicited intracellular effects. Treatment of rat hepatocytes with the catalase inhibitor 3-amino-1,2,4-triazole (2-4 mM for 72 h or 10 mM for 1 h following the hepatocyte attachment period) also led to an up-regulation of mdrlb mRNA and P-glycoprotein expression. Conversely, antioxidants (1 mM ascorbate, 10 mM mannitol, 2% dimethyl sulphoxide, 10 mM N-acetylcysteine) markedly suppressed intrinsic mdr1b mRNA and P-glycoprotein overexpression. Intracellular steady-state levels of the mdrl substrate rhodamine 123, determined as parameter of mdr1-type transport activity, indicated that mdr1-dependent efflux was increased in hepatocytes pretreated with H2O2 or aminotriazole and decreased in antioxidant-treated cells. The induction of mdr1b mRNA and of functionally active mdr1-type P-glycoproteins by elevation in intracellular ROS levels and the repression of intrinsic mdrlb mRNA and P-glycoprotein overexpression by antioxidant compounds support the conclusion that the expression of the mdr1b P-glycoprotein is regulated in a redox-sensitive manner.  (+info)

Susceptibility to hydrogen peroxide and catalase activity of root nodule bacteria. (3/160)

The root nodule bacteria (free-living cells) tested had higher susceptibility to hydrogen peroxide (H2O2) than the other genera of aerobic or facultative anaerobic bacteria tested. The catalase activities tended to have a positive correlation with H2O2 resistance among all bacteria tested. Addition of a catalase inhibitor such as 3-amino-1, 2, 4-triazole increased the susceptibility to H2O2. These results suggest that the lower catalase activity brings about the higher susceptibility of root nodule bacteria to H2O2. Root nodule bacteria seemed to have two or three catalase isozymes during growth and their catalase activities were higher in log phase than in stationary phase, contrary to other genera of bacteria tested.  (+info)

A TATA-binding protein mutant defective for TFIID complex formation in vivo. (4/160)

Using an intragenic complementation screen, we have identified a temperature-sensitive TATA-binding protein (TBP) mutant (K151L, K156Y) that is defective for interaction with certain yeast TBP-associated factors (TAFs) at the restrictive temperature. The K151L,K156Y mutant appears to be functional for RNA polymerase I (Pol I) and Pol III transcription, and it is capable of supporting Gal4-activated and Gcn4-activated transcription by Pol II. However, transcription from certain TATA-containing and TATA-less Pol II promoters is reduced at the restrictive temperature. Immunoprecipitation analysis of extracts prepared after culturing cells at the restrictive temperature for 1 h indicates that the K151L,K156Y derivative is severely compromised in its ability to interact with TAF130, TAF90, TAF68/61, and TAF25 while remaining functional for interaction with TAF60 and TAF30. Thus, a TBP mutant that is compromised in its ability to form TFIID can support the response to Gcn4 but is defective for transcription from specific promoters in vivo.  (+info)

Generation of reactive oxygen species by human mesothelioma cells. (5/160)

Malignant mesothelioma cells contain elevated levels of manganese superoxide dismutase (MnSOD) and are highly resistant to oxidants compared to non-malignant mesothelial cells. Since the level of cellular free radicals may be important for cell survival, we hypothesized that the increase of MnSOD in the mitochondria of mesothelioma cells may alter the free radical levels of these organelles. First, MnSOD activity was compared to the activities of two constitutive mitochondrial enzymes; MnSOD activity was 20 times higher in the mesothelioma cells than in the mesothelial cells, whereas the activities of citrate synthase and cytochrome c oxidase did not differ significantly in the two cell lines. This indicates that the activity of MnSOD per mitochondrion was increased in the mesothelioma cells. Superoxide production was assayed in the isolated mitochondria of these cells using lucigenin chemiluminescence. Mitochondrial superoxide levels were significantly lower (72%) in the mesothelioma cells compared to the mesothelial cells. Oxidant production in intact cells, assayed by fluorimetry using 2',7'-dichlorodihydrofluorescein as a fluorescent probe, did not differ significantly between these cells. We conclude that mitochondrial superoxide levels are lower in mesothelioma cells compared to nonmalignant mesothelial cells, and that this difference may be explained by higher MnSOD activity in the mitochondria of these cells. Oxidant production was not different in these cells, which may be due to the previously observed increase in H2O2-scavenging mechanisms of mesothelioma cells.  (+info)

Arsenic trioxide selectively induces acute promyelocytic leukemia cell apoptosis via a hydrogen peroxide-dependent pathway. (6/160)

Low concentrations of As(2)O(3) (+info)

Role of megalin (gp330) in transcytosis of thyroglobulin by thyroid cells. A novel function in the control of thyroid hormone release. (7/160)

When thyroglobulin (Tg) is endocytosed by thyrocytes and transported to lysosomes, thyroid hormones (T4 and T3) are released. However, some internalized Tg is transcytosed intact into the bloodstream, thereby avoiding proteolytic cleavage. Here we show that megalin (gp330), a Tg receptor on thyroid cells, plays a role in Tg transcytosis. Following incubation with exogenous rat Tg at 37 degrees C, Fisher rat thyroid (FRTL-5) cells, a differentiated thyroid cell line, released T3 into the medium. However, when cells were incubated with Tg plus either of two megalin competitors, T3 release was increased, suggesting that Tg internalized by megalin bypassed the lysosomal pathway, possibly with release of undegraded Tg from cells. To assess this possibility, we performed experiments in which FRTL-5 cells were incubated with either unlabeled or (125)I-labeled Tg at 37 degrees C to allow internalization, treated with heparin to remove cell surface-bound Tg, and further incubated at 37 degrees C to allow Tg release. Intact 330-kDa Tg was released into the medium, and the amount released was markedly reduced by megalin competitors. To investigate whether Tg release resulted from transcytosis, we studied FRTL-5 cells cultured as polarized layers with tight junctions on permeable filters in the upper chamber of dual chambered devices. Following the addition of Tg to the upper chamber and incubation at 37 degrees C, intact 330-kDa Tg was found in fluids collected from the lower chamber. The amount recovered was markedly reduced by megalin competitors, indicating that megalin mediates Tg transcytosis. We also studied Tg transcytosis in vivo, using a rat model of goiter induced by aminotriazole, in which increased release of thyrotropin induces massive colloid endocytosis. This was associated with increased megalin expression on thyrocytes and increased serum Tg levels, with reduced serum T3 levels, supporting the conclusion that megalin mediates Tg transcytosis. Tg transcytosis is a novel function of megalin, which usually transports ligands to lysosomes. Megalin-mediated transcytosis may regulate the extent of thyroid hormone release.  (+info)

Salicylic acid mediated by the oxidative burst is a key molecule in local and systemic responses of cotton challenged by an avirulent race of Xanthomonas campestris pv malvacearum. (8/160)

We analyzed the production of reactive oxygen species, the accumulation of salicylic acid (SA), and peroxidase activity during the incompatible interaction between cotyledons of the cotton (Gossypium hirsutum) cv Reba B50/Xanthomonas campestris pv malvacearum (Xcm) race 18. SA was detected in petioles of cotyledons 6 h after infection and 24 h post inoculation in cotyledons and untreated leaves. The first peak of SA occurred 3 h after generation of superoxide (O(2)(.-)), and was inhibited by infiltration of catalase. Peroxidase activity and accumulation of SA increased in petioles of cotyledons and leaves following H(2)O(2) infiltration of cotyledons from 0.85 to 1 mM. Infiltration of 2 mM SA increased peroxidase activity in treated cotyledons and in the first leaves, but most of the infiltrated SA was rapidly conjugated within the cotyledons. When increasing concentrations of SA were infiltrated 2. 5 h post inoculation at the beginning of the oxidative burst, the activity of the apoplastic cationic O(2)(.-)-generating peroxidase decreased in a dose-dependent manner. We have shown that during the cotton hypersensitive response to Xcm, H(2)O(2) is required for local and systemic accumulation of SA, which may locally control the generation of O(2)(.-). Detaching cotyledons at intervals after inoculation demonstrated that the signal leading to systemic accumulation of SA was emitted around 3 h post inoculation, and was associated with the oxidative burst. SA produced 6 h post infection at HR sites was not the primary mobile signal diffusing systemically from infected cotyledons.  (+info)

  • Evaluates the risks to human health and the environment posed by exposure to amitrole, a herbicide with a very wide spectrum of activity against annual and perennial broad leaf and grass type weeds. (
  • The book further concludes that amitrole poses no significant threat to the environment, that levels in food and drinking-water should be extremely low, and that the herbicide poses no threat to the health of workers or the general population when manufactured and used as recommended. (
  • Amitrole is a nonselective systemic triazole herbicide and taken in by the target plant as a foliar spray. (
  • As an herbicide, it is known as aminotriazole, amitrole or amitrol. (
  • Minimise herbicide contact with the soil and other vegetation as Amitrole is non-selective, residual and corrosive. (
  • Spot-spraying of hexazinone and amitrole/atrazine in the establishment of first and second rotations of Pinus radiata in south-western Victoria. (
  • Recent studies done in Sweden this year, have found a link between hive collapse disorder and a number of pesticides banned throughout Europe ,including 2,4D Amitrole, Amitraz, 1,3-dichloropropene, Atrazine etc. ehich are still used throughout the Canada,Britian, U.S.A and China is are guilty of using these pesticides and more. (
  • Pesticide Action Network lists amitrole as a carcinogen and suspected endocrine disruptor. (
  • Amitrole is classified as a Restricted Use Pesticide and may be purchased and used only by certified applicators. (
  • Amitrole treatment of etiolated barley seedlings leads to deregulation of tetrapyrrole synthesis and to reduced expression of Lhc and RbcS genes. (
  • Observed similarities between the bleaching symptomology displayed by these herbicides and amitrole suggested that hydroxytriazolopyrimidines could be acting as elaborate propesticides of amitrole, and this was subsequently demonstrated in plant metabolism studies using Amaranthus retroflexus. (
  • Eventually, it was decided to use preparations of powerful, highly toxic herbicides including 2,4-D, amitrole and bromacil to control the outbreak. (
  • A review of studies on the environmental fate of amitrole concludes that the compound is relatively rapidly degraded in the environment, with no evidence of either bioaccumulation or entry into the food chain. (
  • Amitrole was and is used widely across irrigation areas of Victoria as a control to aquatic weeds such as couch grass in drains and channels. (
  • These findings support the conclusion that amitrole is goitrogenic, causing thyroid hypertrophy and hyperplasia, depletion of colloid, and increased vascularity. (
  • Although studies of occupationally-exposed workers are largely reassuring, the book recommends annual monitoring of thyroid function in workers regularly handling amitrole at either the formulation or application stage. (
  • Studies in both humans and animals show that amitrole is rapidly absorbed and rapidly excreted in urine in an unchanged form. (
  • Replacement of NF by other inhibitors of carotenoid biosynthesis (such as amitrole) revealed that the growth and pigmentation phenotype is not coupled to the LHCB1.2 mRNA accumulation phenotype. (
  • Amitrole / published under the joint sponsorship of the United Nations Environment Programme, the International Labour Organisation, and the World Health Organization. (
  • Approval was first given in September 1962 at the Intergovernmental Committee on Pesticides for the State Rivers and Water Supply Commission (SRWSC) to use amitrole provided that the level in domestic drinking water did not exceed 300 parts per billion. (
  • Other information on identity and properties Amitrole is a white, crystalline solid with a molecular weight of 84 and a melting point of 150-153 C. It is soluble in water to the extent of 28 g/100 g and in ethanol and methanol to an extent of 26 g/100 g. (
  • It also means that levels of amitrole under 10 ppb, would not have been regarded as "dangerous" as recently as 2011 before the new Guidelines were published. (
  • Treat the new growth with 2,4-D or Amitrole, misting the foliage to keep the runoff onto the ground to a minimum. (
  • In June 1963 the Commission adopted a maximum concentration of amitrole in streams of 2 ppb. (
  • Amitrole, which appears to act by inhibiting the formation of chlorophyll, is widely used around orchard trees, on fallow land prior to sowing, along roadsides and railway lines, and for weed control in ponds. (