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PubMedDate not supplied

Behavior of 14C-atrazine in Argentinean topsoils under different cropping managements.

Atrazine (6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine) behavior was studied in four surface soils during incubations in laboratory conditions. Soils were chosen in relation to their cropping management (tillage and no tillage) and crop rotation system (continuous soybean [Glycine mar (L.) Merr.] and maize (Zea mays L.)-soybean rotation). A natural soil under brushwood was sampled as a reference. Atrazine use in field conditions was associated with maize cropping, thus only one soil received atrazine every other year. Atrazine behavior was characterized through the balance of 14C-U-ring atrazine radioactivity among the mineralized fraction, the extractable fraction, and the nonextractable bound residues. Soil organic matter capacity to form bound residues was characterized using soil size fractionation. Accelerated atrazine mineralization was only observed in the soil receiving atrazine in field conditions. Atrazine application every other year was enough to develop a microflora adapted to triazine ring mineralization. Bound residue formation was rapid and increased with soil organic matter content. The coarsest soil size fractions (2000-200 and 200-50 microm) containing the nonhumified organic matter presented the highest capacity to form bound residues. No effect of tillage system was observed, probably because of the uniform sampling depth at 20 cm, hiding the stratification pattern of soil organic matter in non-tilled soils.

Agriculture↗
PubMedDate not supplied

Herbicide loading to shallow ground water beneath Nebraska's Management Systems Evaluation Area.

Better management practices can counter deterioration of ground water quality. From 1991 through 1996 the influence of improved irrigation practices on ground water pesticide contamination was assessed at the Nebraska Management Systems Evaluation Area. Three 13.4-ha corn (Zea mays L.) fields were studied: a conventional furrow-irrigated field, a surge-irrigated field and a center pivot-irrigated field, and a center pivot-irrigated alfalfa (Medicago sativa L.) field. The corn fields received one identical banded application of Bicep (atrazine [6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4,-diamine] + metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamidel) annually; the alfalfa field was untreated. Ground water samples were collected three times annually from 16 depths of 31 multilevel samplers. Six years of sample data indicated that a greater than 50% reduction in irrigation water on the corn management fields lowered average atrazine concentrations in the upper 1.5 m of the aquifer downgradient of the corn fields from approximately 5.5 to <0.5 microg L(-1). Increases in deethylatrazine (DEA; 2-chloro-4-amino-6-isopropylamino-s-triazine) to atrazine molar ratios indicated that reducing water applications enhanced microbial degradation of atrazine in soil zones. The occurrence of peak herbicide loading in ground water was unpredictable but usually was associated with heavy precipitation within days of herbicide application. Focused recharge of storm runoff that ponded in the surge-irrigated field drainage ditch, in the upgradient road ditch, and at the downgradient end of the conventionally irrigated field was a major mechanism for vertical transport. Sprinkler irrigation technology limited areas for focused recharge and promoted significantly more soil microbial degradation of atrazine than furrow irrigation techniques and, thereby, improved ground water quality.

Agriculture↗
PubMedDate not supplied

Modeling the effects of tillage management practices on herbicide runoff in northern Italy.

The need to quantitatively predict pesticide runoff and erosion under cropping system management has gained increasing importance. In Europe, predictive models have not yet been fully validated because of the lack of field data sets. The objective of this study was to validate the capability of PRZM (Pesticide Root Zone Model) 3.12 to predict water runoff, sediment erosion, and associated transport of atrazine (6-chloro-N(2)-ethyl-N(4)-isopropyl-1,3,5-triazine-2,4-diamine), terbuthylazine (N(2)-tert-butyl-6-chloro-N(4)-ethyl-1,3,5-triazine-2,4-diamine), and metolachlor [2-chloro-6'-ethyl-N-(2-methoxy-l-methylethyl)acet-o-toluidide] under common tillage management practices found in northern Italy. A 2-yr field data set was used to evaluate the model. Results showed that the model could qualitatively simulate significant differences of water runoff, soil erosion, and associated herbicide losses between conventional tillage (CT) and minimum tillage (MT) for a winter barley (Hordeum vulgare L.) cover crop. For MT, water runoff, soil erosion, herbicide losses in water runoff and eroded sediment, and the proportion of herbicide loss via sediment erosion were significantly lower than for CT. The model failed to correctly simulate event-based herbicide concentration, water runoff, and soil erosion. The model usually underestimated pesticide runoff events with high rainfall intensity and low daily precipitation volume, and overestimated runoff events with low intensity and high volume. The main reason was that the description of runoff and erosion processes is rather empirical in the model and not physically based. Moreover, model calculations do not adequately reflect the relationships between soil erosion intensity and chemical concentration in sediment losses, leading to discrepancies between predictions and field observations.

Agriculture↗
PubMedDate not supplied

Residual and contact herbicide transport through field lysimeters via preferential flow.

Usage of glyphosate [N-(phosphonomethyl)-glycine] and glufosinate [2-amino-4-(hydroxy-methylphosphinyl)butanoic acid] may reduce the environmental impact of agriculture because they are more strongly sorbed to soil and may be less toxic than many of the residual herbicides they replace. Preferential flow complicates the picture, because due to this process, even strongly sorbed chemicals can move quickly to ground water. Therefore, four monolith lysimeters (8.1 m(2) by 2.4 m deep) were used to investigate leaching of contact and residual herbicides under a worst-case scenario. Glufosinate, atrazine (6-chloro-N(2)-ethyl-N(4)-isopropyl-1,3,5-triazine-2,4-diamine), alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl) acetamide], and linuron (3-3,4-dichlorophenyl-1-methoxy-1-methylurea) were applied in 1999 before corn (Zea mays L.) planting and glyphosate, alachlor, and metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one] were applied in 2000 before soybean [Glycine max (L.) Merr.] planting. A high-intensity rainfall was applied shortly after herbicide application both years. Most alachlor, metribuzin, atrazine, and linuron losses occurred within 1.1 d of rainfall initiation and the peak concentration of the herbicides coincided (within 0.1 d of rainfall initiation in 2000). More of the applied metribuzin leached compared with alachlor during the first 1.1 d after rainfall initiation (2.2% vs. 0.035%, P < 0.05). In 1999, 10 of 24 discrete samples contained atrazine above the maximum contaminant level (atrazine maximum contaminant level [MCL] = 3 mug L(-1)) while only one discrete sample contained glufosinate (19 mug L(-1), estimated MCL = 150 mug L(-1)). The results indicate that because of preferential flow, the breakthrough time of herbicides was independent of their sorptive properties but the transport amount was dependent on the herbicide properties. Even with preferential flow, glyphosate and glufosinate were not transported to 2.4 m at concentrations approaching environmental concern.

Adsorption↗
PubMed1990

Generation of radical anions of nifurtimox and related nitrofuran compounds by ascorbate.

Nifurtimox analogues bearing triazol-4-yl, benzimidazol-1-yl, triazin-4-yl or related groups as counterpart of the (5-nitro-2-furfurylidene) amino group were reduced to their nitro anion radicals by ascorbate in anaerobic solutions at high pH. The ESR spectra of the radical anions showed hyperfine spin couplings restricted to the nitrofuran moiety. With these compounds, the spin density at the nitro group was greater than with nifurtimox, nitrofurazone and nitrofurantoin. At neutral pH, solutions containing ascorbate and nitrofuran derivatives consumed oxygen, the compounds bearing unsaturated nitrogen heterocycles being the most effective. Superoxide dismutase and catalase decreased the rate of oxygen consumption, thus demonstrating the production of superoxide and hydrogen peroxide, respectively. NMR spectra of the triazol-4-yl and triazin-4-yl nitrofuran derivatives showed a deshielding effect for the azomethine proton, which was undetectable with nifurtimox and nitrofurazone.

Ascorbic Acid↗
PubMed1987

Quaternary heterocyclylamino beta-lactams. VI. In vitro and in vivo antibacterial properties of L-642,946 and L-652,813, a long acting cephem.

Two newly described quaternary heterocyclylamino beta-lactams, L-642,946 and L-652,813, were shown to exhibit potent activity against a broad spectrum of aerobic and anaerobic bacteria in vitro. The activity of these agents in vitro translated well to chemotherapeutic activity in experimental bacteremias in mice. Substitution of the thiadiazine moiety of L-642,946 with a triazine moiety effected a marked change in the pharmacokinetics of the new derivative, L-652,813. In mice given a 20 mg/kg subcutaneous dose, the peak serum concentration and the half-life of L-652,813 were about three times greater than those of L-642,946 and the area under the serum concentration/time curve was increased by about 5-fold. The pharmacokinetics of L-652,813 in mice and in rhesus monkeys more closely resembled those of ceftriaxone which carries the same triazine moiety on the C-3 side chain.

Animals↗
PubMed2000

The library of p-nitrophenyl esters of oligopeptides as a model to study the anticancer drug-peptide conjugates activated during tumor angiogenesis.

An indexed library of oligopeptide p-nitrophenyl esters immobilized via methoxy-1,3,5-triazine scaffold on the cellulose support, was synthesized by the step by step procedure and by segment coupling, involving 2-chloro-4,6-dimethoxy-1,3,5-triazine as a condensing reagent. The substrate specificity towards homogenate supernatant of mouse lung cancer LL2 cells has been studied.

Animals↗
PubMed2005

Bound 14C-metsulfuron-methyl residue in soils.

Bound residue(BR) of 14C-metsulfuron-methyl (14C-BR) in seven kinds of soil was significantly negative-related to soil pH and positive-related to the clay content during the initial 20 d of incubation, but only was significantly negative-related to soil pH after 30 d incubation. Again, the soil pH was found to be the dominant factor affecting BR formation from 14C-metsulfuron-methyl among the basic properties(soil pH, clay, OM and CEC etc.) of soil. The maximum content of 14C-BR in the 7 soils accounted for 19.3% - 52.6% of applied amount. In addition, the composition of the 14C-BR in fluvio marine yellow loamy (S7) at the 90 d of incubation was identified using the coupling technique of LC-MS and isotope tracing method. The results showed that the 14C-[2-amino-4-hydroxyl-6-methyl-1, 3, 5]-triazine, 14C-[2-amino-4-methoxy-6-methyl-1, 3, 5]-triazine and 14 C-metsulfuron-methyl parent compound constituted the main components of the BR derived from 14 C-metsulfuron-methyl in the S7. The relative percentage of the three compounds accounted for 41.4%, 35.8% and 19.3% of total recovery radioactivity, respectively. The results also indicated that a non-radioactive component, 2-methylformate-benzenesulfonyl-isocyanate, one of the degraded products of metsulfuron-methyl in soil, was also found to be one of the components of the BR. The parent compound in BR can well explain the phytotoxic effect on substitution crops caused by the BR derived from metsulfuron-methyl in soil.

Aluminum Silicates↗
PubMedDate not supplied

Regression analysis of pesticide use and breast cancer incidence in California Latinas.

An evaluation of pesticide use data and breast cancer incidence rates in California Hispanic females was conducted via a regression analysis. The analysis used 1988-2000 data from the California Cancer Registry, the population-based cancer registry that monitors cancer incidence and mortality in California. It also used pesticide use data from 1970-1988 from the California Department of Pesticide Regulation. California is the leading agricultural state in the United States, and more than a quarter of all pesticides in the United States are applied there. Hispanic (Latina) females are commonly employed in agricultural operations. The authors performed regression analysis of county-level specific pesticide use data (pounds of active ingredients applied) for two classes of pesticides, organochlorines and triazine herbicides, against the breast cancer incidence rates among Latinas, controlling for age, socioeconomic status, and fertility rates, using negative binomial regression models. A total of 23,513 Latinas were diagnosed with breast cancer in California during the years 1988-1999. Risk of breast cancer was positively and significantly associated with age and socioeconomic status, and inversely and significantly associated with fertility levels. With respect to pesticides, breast cancer was positively associated with pounds of the organochlorines methoxychlor (adjusted incidence rate ratio [IRR] for highest quartile = 1.18; confidence interval [CI] = 1.03-1.35) and toxaphene (IRR = 1.16; CI = 1.01-1.34). No significant associations were found for the triazine herbicides atrazine and simazine.

Adult↗
PubMed1990

New 5H-[1,3]thiazolo[3,2-a]pyrido[3,2-e]pyrimidine derivatives as diuretics.

New 5H-[1,3]thiazolo[3,2-a]pyrido[3,2-e]pyrimidines 1 and 6,10-dihydro-5H-pyrido[3',2':5,6]pyrimido[2,1-c] [1,2,4]triazines 4 with 5-one, 5-thione or 5-hydrazono substituents and in some cases 1,2,3,4 or 8,9 hydrogenated are synthetized. The diuretic, natriuretic and kaliuretic activities of these compounds in Wistar rats at a dose of 24 mg/kg were estimated. A series of 24 possible derivatives of 1 and 4 possessing diuretic and saliuretic activities are investigated for structure-activity relationships in light of Fujita-Ban model. The Fujita-Ban group contributions have been calculated for different structural variations on the parent ring 1a. It is observed that the hydrogenation of pyridine, [1,3]thiazole or [1,2,4]triazine rings on 1 or 4 decrease the diuretic and saliuretic activities.

Animals↗
PubMed1986

Hexachlorobenzene levels in multimedia environmental samples from selected chemical production plants.

A sampling and analysis program was conducted to determine hexachlorobenzene (HCB) levels in air, water, soil and sediment. Nine industrial plants were selected, representing six major industries: perchloroethylene, trichloroethylene, carbon tetrachloride, chlorine, triazine herbicides and pentachloronitrobenzene. Of the six industries sampled, higher concentrations of HCB were associated with the production of perchloroethylene, trichloroethylene and carbon tetrachloride. In the one plant that produced only carbon tetrachloride, HCB levels were quite low. HCB concentrations were relatively high in samples from the pentachloronitrobenzene plant, i.e., low microgram/m3 range in air and generally over 100 micrograms/g along roads within the plant. Very low levels of HCB were associated with plants producing chlorine and triazine herbicides. Several different waste-disposal methods were used at the perchloro- and trichloroethylene plants that were sampled. The highest level of HCB was detected in air and soil at the plant using on-site landfill and open-pit storage. High HCB levels were detected in loading and transfer areas at plants using off-site disposal methods. Lower HCB levels were found at plants using on-site incineration, but downwind air concentrations were elevated above background at these plants. Production of perchloro- and trichloroethylene by low-temperature oxychlorination and incineration of liquid bottom wastes resulted in high levels (micrograms/m3) of HCB in the air but relatively low levels in the effluent water.(ABSTRACT TRUNCATED AT 250 WORDS)

Chemical Industry↗
PubMed1978

[Soluble high molecular weight derivatives of pancreatic trypsin inhibitor. Isolation and properties of the inhibitor bound to carboxymethyl cellulose and diethylaminoethyl dextran].

Soluble preparations of pancreatic trypsin inhibitor, which is bound to carboxymethyl cellulose- and diethylaminoethyl dextran activated by chlorine derivatives of s-triazine were isolated. The activity of the pancreatic inhibitor bound to carboxymethyl cellulose treated by 2-amino-4,6-dichloro-s-triazine was completely retained. Simultaneously, the reaction cyanuric chloride activation of water-soluble polysaccharide carriers in a non-aqueous solvent was studied by assaying the amount of chlorine atoms on the treated matrix. The gel-filtration experiments show that the cross-linkages between polysaccharide molecules appear during the activation reaction. A structural model of a carboxymethyl cellulose-bound pancreatic inhibitor is proposed.

Carboxymethylcellulose Sodium↗
PubMed1983

Almitrine bismesylate: pharmacological review and structure-activity relationships.

In the anaesthetized dog almitrine bismesylate (A) increases ventilation after i.v. injections of more than 100 ug X kg-1. This ventilatory stimulation is due to the specific agonistic action of A on the peripheral chemoreceptors. With lower doses of A no modification of ventilation is recorded even though PaO2 significantly increases. The mechanisms by which A induces pulmonary gas exchange improvement are not clearly demonstrated. A long lasting potentiation of local hypoxic pulmonary vasoconstriction was initially postulated but more recent experimental results recorded on animals with heterogeneously ventilated lungs do not support this hypothesis. However, a redistribution of pulmonary blood flow due to the transient vasoconstrictor effect of A cannot be excluded: it might divert the blood from the well perfused lung bases towards the less well perfused lung apex. Other authors have demonstrated that undetected small ventilatory changes might improve alveolar ventilation and raise PaO2. The almitrine bismesylate molecule is a successful example of pharmacochemical research applied to bronchopulmonary pathology. By using qualitative structure activity relationships it has been possible to choose from a series of triazine derivatives, this remarkable molecule, exerting a clear tropism for the pulmonary tract with a dual effect improving both ventilatory and gasometric parameters through peripheral chemoreceptor stimulation, and characterized by a rapid onset of action and a durable activity. In this respect, the di-allyl-amino-triazine moiety may be considered as an inducer of gasometric and ventilatory effects. The piperazine nucleus is mainly responsible for the ventilatory/gasometric dissociation and for the kinetics of these pulmonary actions. Finally, the bisparafluorobenzydryl component is a 'modulator' of intensity of gasometric effects.

Almitrine↗
PubMed1980

Spectrophotometric screening method for acetaminophen in serum and plasma.

We describe a simple, economical procedure for rapidly detecting acetaminophen in serum or plasma. The method is based upon the reduction by the drug of ferric 2,4,6-tris(2-pyridyl)-s-triazine, at an acidic pH, to ferrous 2,4,6-tris(2-pyridyl)-S-triazine complex, which absorbs maximally at 593 nm. Absorbance and acetaminophen concentration are linearly related from 25 to 400 mg/L, and so therapeutic and toxic concentrations can be measured. The method is accurate; day-to-day CV's for two pooled control specimens (103 and 227 mg/L) were 4.4 and 6.6%. Correlation studies, with an established nitration method and with the free-radical diphenylpicrylhydrazyl dye method, showed correlation coefficients of 0.985 and 0.915, respectively. Of 25 commonly used drugs tested, only levodopa, oxyphenylbutazone, and phenylephrine interfere significantly. Interference from salicylate, salicylamide, and phenylbutazone was insignificant.

Acetaminophen↗
PubMed1995

[Interaction of derivatives of 3-(indol-3-yl)propionic, nicotinic, and 1-nitroanthraquinone-2-carboxylic acid with pyrimidine nucleosides and their 5'-amino-5'-deoxy analogs].

The reaction of 5'-amino-2',5'-dideoxyuridine and 5'-amino-5'-deoxy-2',3'-O-ethoxymethyliden-6- azauridine with 3-(3-indolyl)propionic or 1-nitroanthraquinon-2-carboxylic acids in THF in the presence of 2-ethoxy-1-ethoxycarbonyl-1,2-dihydroquinoline (EEDQ) resulted in the corresponding amide derivatives. The reaction conditions of the standard procedure for the removal of the O-alkylidene protecting group turned out to be too severe for the 5'-N-acylamide derivatives of 6-azauridine. 5'-Deoxy-5'-[3-(3-indolyl)propionyl-amino]-6-azauridine was synthesized from 5'-amino-5'-deoxy-6-azauridine and 3-(3-indolyl)propionic acid in THF in the presence of EEDQ. A reaction between 5'-O-tosyl-2',3'-O-ethoxymethyliden-6-azauridine and 3-aminopropanol gave 3-(3-hydroxypropylamino)-2-(2',3'-O-ethoxymethylidene-beta- D-ribofuranosyl)-as-triazine-5(2H)-one, the structure of which was confirmed also by synthesis from O2,5'-anhydronucleoside and 3-aminopropanol followed by further chemical transformations. A reaction of 3-(3-hydroxypropylamino) derivative obtained with nicotinoyl chloride prepared in situ, or with 1-nirtoanthraquinon-2-carboxylic acid in the presence of DCC with subsequent deprotection, afforded 3-[(3-pyridin-3-ylcarboxy)propylamino]- or 3-[3-(1-nitroanthraquinon-2-carboxy)propylamino]-2-beta-D-ribof ura nosyl-as- triazine-5(2H)-one, respectively. Structures of the nucleosides prepared were examined by 1H NMR spectroscopy. 2',5'-Dideoxy-5'-[(1-nitroanthraquinon-2-carbonyl)amino]uridine at a 10(-4) M concentration was shown to inhibit thymidine incorporation into cell DNA (CE50 10(-5) M) by 72%.

Amines↗
PubMed1994

The concept of superactive esters. Could peptide synthesis be improved by inventing superactive esters?

According to the concept presented, esters forming an amide (peptide) bond by the mechanism SN#DN or SN#*DN involving fast decay of the tetrahedral intermediate may behave as 'superactive acylating reagents'. These should render coupling involving less reactive substrates, i.e. sterically hindered or 'difficult coupling sequences', much faster and more uniform than classic active esters. In extremely cases this advantage could be significant, and the calculated increase in time required for 99.9% coupling substrates 6 pKa units less reactive than the standard ones reaches 2,512,000 tau 1/2 units for classic active esters, but only 631 tau 1/2 units for reaction involving 'superactive esters'. The postulated change of mechanism is expected for esters bearing a leaving group which is able to undergo an additional, synchronous, energetically favored process accompanying its departure, as has been observed in the case of triazine esters. Some advantages of triazine superactive esters in the condensation of sterically hindered substrates are demonstrated.

Amino Acid Sequence↗
PubMed1995

Determinants of O6-alkylguanine-DNA alkyltransferase activity in human colon cancer.

The DNA repair protein O6-alkylguanine-DNA alkyltransferase (alkyltransferase) repairs cytotoxic DNA O6-alkylguanine adducts induced by the nitrosoureas, triazines, and tetrazines. In this study, we determined whether there was a relationship between alkyltransferase activity in colon cancer and that of adjacent normal mucosa, and whether there were demographic patient characteristics which correlated with alkyltransferase expression in either tissue. Alkyltransferase activity and expression of the alkyltransferase gene, MGMT, were measured in 49 paired primary colon cancer samples and adjacent normal appearing mucosa. Alkyltransferase activity was found in all samples. The mean activity was higher in the tumor than the mucosa (r = 0.374, P < 0. 01), although the low correlation coefficient suggested that multiple factors influence the alkyltransferase activity. MGMT mRNA could also be detected in all samples and was highly correlated with alkyltransferase activity (r = 0.64, P < 0.001). No correlation was found between alkyltransferase activity and age, or gender of the patient, or location of the tumor, although activity tended to be higher in patients with lower stage disease. Thus, alkyltransferase activity is present in most, if not all, colon cancer samples, suggesting that it could play an important role in chemotherapeutic resistance of human colon cancer. Patients with colon cancer would appear to be prime candidates for studies utilizing O6-benzylguanine to deplete alkyltransferase prior to therapy with a nitrosourea, triazine, or tetrazine.

Colon↗
PubMed1962

Depression of muscle spindle activity--a new type of pharmacological action?

The effect of 2,4-di(diethylamino)-6-(2-phenylacetylhydrazino)-1,3,5-triazine (Ciba 28882-Ba) injected intravenously on the activity of de-efferented muscle spindles of the tibialis anterior and extensor digitorum longus muscles of anaesthetized cats, and on gamma-motoneurones of decerebrate cats, was investigated. The drug depressed both the static activity of muscle spindles and the spontaneous activity of gamma-motoneurones. In contrast, the response of muscle spindles to rapid stretch was not affected. The effect of 28882-Ba on the activity of the muscle spindles resembled that of progressive unloading or shortening of the muscle. 28882-Ba antagonized excitation of the muscle spindle by suxamethonium. The effect of 28882-Ba on the response of the gamma-motoneurones to various driving stimuli was not predictable.

Animals↗