Search results for " TOXICITY"

Acute Toxicity Testing in Vitro and the Classification and Labelling of Chemicals

1996

Prediction of acute toxicity of organophosphorus pesticides using topological indices

2007

Topological indices were used in the prediction of the acute toxicity (intraperitoneal and oral LD(50)) of organophosphorus pesticides on rats. Models with six variables for the prediction of LD(50)-i.p. (r = 0.849, Q(2) = 0.613) and eight variables for LD(50)-oral (r = 0.906, Q(2) = 0.701) were selected. External group and cross-validation by use of leave-n-out tests were also performed in order to assess the stability and the prediction performance of the selected topological models.

Acute and short-term toxicity of 2,3,4,6-tetrachlorophenol in rats

1981

Quantitative retention- and migration-toxicity relationships of phenoxy acid herbicides in micellar liquid chromatography and micellar electrokinetic…

2001

Abstract The need to obtain a tool for estimation of toxicity parameters for chemicals supports, the postulation of predictive models as an alternative to conventional classical assays. The use of micellar solutions of Brij35 as mobile phases in reversed phase liquid chromatography has proven to be valid in predicting some biological activities of different kinds of drugs. In this paper, the correlations between retention of phenoxy acids using different concentrations of Brij35 as micellar mobile phase in micellar liquid chromatography (MLC) and migration in micellar electrokinetic chromatography (MEKC) with several toxicity parameters are studied. Adequate correlations retention- and migr…

Toxicity of binary mixtures of Cu, Cr and As to the earthworm Eisenia andrei

2020

AbstractChromated copper arsenate (CCA) mixtures were used in the past for wood preservation, leading to large scale soil contamination. This study aimed at contributing to the risk assessment of CCA-contaminated soils by assessing the toxicity of binary mixtures of copper, chromium and arsenic to the earthworm Eisenia andrei in OECD artificial soil. Mixture effects were related to reference models of Concentration Addition (CA) and Independent Action (IA) using the MIXTOX model, with effects being related to total and available (H2O and 0.01 M CaCl2 extractable) concentrations in the soil. Since only in mixtures with arsenic dose-related mortality occurred (LC50 92.5 mg/kg dry soil), it wa…

Effects of temperature on the acute toxicity of heavy metals (Cr, Cd, and Hg) to the freshwater crayfish, Procambarus clarkii (Girard).

1987

Chromium, an essential trace element for humans and animals is involved in normal carbohydrate metabolism; however, it is toxic at high concentrations. There is no evidence that cadmium and mercury are biologically essential but their toxicity for organisms is well known. Both cause toxic effects at low concentrations to most organisms, especially in combination with other environmental variables such as temperature. Lake Albufera and the surrounding rice field waters are subjected to very heavy loads of sewage and toxic industrial residues (including heavy metals) from the many urban and waste waters in this area. In 1978, the American red crayfish Procambarus clarkii appeared in lake Albu…

Nephrotoxic and hepatotoxic effects of chromium compounds in rats

1986

The nephrotoxic, hepatotoxic and cardiotoxic actions of hexavalent chromium compounds, as well as their effects on lung, blood and circulation may contribute to the fatal outcome of chromium intoxication. Although trivalent chromium have been regarded as relatively biologically inert, there are a few salts of chromium III that have been found to be carcinogenic when inhaled, ingested or brought in contact with the tissues. Sensitive persons and industry workers have been subjects of dermatitis, respiratory tract injuries and digestive ulcers due to chromium compounds. In this work, the authors have studied the effect of trivalent and hexavalent chromium compounds on rats measuring the trans…

Tumor formation in the neonatal mouse bioassay indicates that the potent carcinogen dibenzo[def,p]chrysene (dibenzo[a,l]pyrene) is activated in vivo …

2004

The hexacyclic aromatic hydrocarbon dibenzo[def,p]chrysene, better known as dibenzo[a,l]pyrene (DBP) in the field of chemical carcinogenesis, is present in the environment as a combustion product of organic matter. This compound is probably the strongest chemical carcinogen ever tested. As ultimate genotoxic metabolites of DBP two electrophilically reactive species are discussed: (i) radical cations generated by one-electron oxidation, and (ii) fjord region dihydrodiol epoxides formed via the trans-11,12-dihydroxy 11,12-dihydro derivative of DBP (11,12-dihydrodiol). In order to delineate the metabolic pathway(s) involved in tumor formation by DBP, newborn Crl:CD-1(ICR)BR mice were intraperi…

Aß(25-35) and its C-and/or N-blocked derivatives: copper driven structural features and neurotoxicity

2006

The toxic properties of beta-amyloid protein, Abeta(1-42), the major component of senile plaques in Alzheimer's disease, depend on nucleation-dependent oligomerization and aggregation. In addition, Abeta(1-42) toxicity is favored by the presence of trace metals, which affect the secondary structure of the peptide. A peptide comprising 11 residues within Abeta(1-42) [Abeta(25-35)] aggregates and retains the neurotoxic activity of Abeta(1-42). We have used both Abeta(25-35) and its C-amidated or N-acetylated/C-amidated derivatives to investigate the role of copper(II) in modulating the conformation and aggregation state as well as the neurotoxic properties of amyloid peptides. Electrospray io…

Alloimmune responses between Acropora hemprichi conspecifics: nontransitive patterns of overgrowth and delayed cytotoxicity

1994

Allogeneic interactions between Acropora hemprichi (Ehrenberg) colonies were followed in situ up to 18 mo between 1990 and 1992 in Eilat, Red Sea. We established all 21 possible branch pair combinations among seven large colonies in three to eight replicates each (n=92 pairs), in addition in 14 pairs of grafts within-colonies. All isografts resulted in fusion. Allogeneic interactions revealed a variety of effector mechanisms which involved the appearance of dark blue-purple color in the tissues of interacting branch tips (<1 cm), unilateral overgrowths (1.0 to 1.5 mm mo-1 for 1 to 8 mo), rejections, healings, continuous overgrowths, reversals, repeated rejections and more. Direction of over…