Oral toxicity of bis(2-ethylhexyl) phthalate during pregnancy and suckling in the Long-Evans rat

Bis(2-ethylhexyl) phthalate (DEHP) is a compound widely used in plastics technology to impart flexibility to rigid polymers. We sought to determine whether the oral exposure of female rats to DEHP during gestation and suckling produces alterations in the litter. Female rats were exposed to different concentrations of DEHP suspended in drinking water (32.5 and 325 microl/litre) from day 1 of pregnancy to day 21 after delivery. Pup body weight gain and kidney, liver and testes weight was measured at different times (21, 28, 35, 42 and 56 days) after birth. Plasma concentrations of DEHP and histopathological alterations in kidneys, liver and testes were also studied. In addition, the ability of female pups (1 month of age) to perform a learned avoidance test, the 'beam walking' test, was evaluated. Perinatal exposure to DEHP produced no statistically significant changes in the body weight gain of offspring. Conversely, it produced a significant decrease in kidney and testes relative weight (organ/body weight) with a significant increase in relative liver weight. Signs of histological damage in kidneys, liver, and particularly testes, were observed. Pups exposed perinatally to the highest concentration of DEHP elicited a significant increase in the time necessary to perform the beam walking test.     

Effects of bis(2-ethylhexyl) phthalate on chromosomes of human leukocytes and human fetal lung cells

Blood from two male and two female donors was exposed at 37degrees for 4 hr to concentrations of 60.0, 6.0, 0.6, and 0.06 mug of a widely used plasticizer, bis (2-ethylhexyl) phthalate, per milliliter of blood. The bis(2-ethylhexyl) phthalate was solubilized with polysorbate 80. Appropriate polysorbate and nonpolysorbate controls also were established. Following the 4 hr of incubation, phytohemagglutinin was added and tissue cultures were established. In addition, human fetal lung cells were exposed in tissue culture to a medium containing 6.0 mug/ml of bis(2-ethylhexyl) phthalate in polysorbate 80 for 5 days. Similar controls also were established for these experiments. Analysis of chromosome preparations from all cultures obtained failed to show any increased evidence of isochromatid and chromatid breaks or gaps or abnormal forms at any studied concentration when compared to the control cultures. In addition, analysis of fetal lung cell preparations for aneuploidy failed to reveal any differences between cells from study and control cultures. This study involved a short-term exposure to bis(2-ethylhexyl) phthalate in various concentrations which did not cause damage in leukocytes or fetal lung cells.     

A novel extractant bis(2-ethylhexyl) ((2-ethylhexylamino)methyl) phosphine oxide for cerium(IV) extraction and separation from sulfate medium

By introducing the amine group into phosphorus extractant, a novel aminophosphine compound bis(2-ethylhexyl) ((2-ethylhexylamino)methyl) phosphine oxide (DEHAPO, abbreviated as A) was synthesized for the extraction of cerium (IV) (Ce(IV)) from sulfate medium (H₂SO₄). The influence factors including extractant concentration, H₂SO₄ concentration and temperature on the Ce(IV) extraction were investigated and discussed. It is found that the extraction ability of Ce(IV), thorium (IV) (Th(IV)) and rare earths (REs(III)) (La, Gd, Yb) decreases in sulphate medium in the following order: Ce(IV) > Th(IV) > REs(III). The extraction process is an exothermic reaction and the thermodynamic parameters were calculated. The extracted complex of Ce(HSO₄)₂SO₄·A in loaded organic solution was identified by the slope methods and further proved by FT-IR spectral analysis. Stripping studies indicate that Ce(IV) can be effectively stripped from the organic phase. The results of separation factors (β) and saturation loading capacity demonstrate that DEHAPO could be used to selectively extract Ce(IV) from sulphate medium with high separation efficiency and good extraction ability.     

The effect of protein relaxation on charge-charge interactions and dielectric constants of proteins

The effect of the reorganization of the protein polar groups on charge-charge interaction and the corresponding effective dielectric constant (epsilon(eff)) is examined by the semimicroscopic version of the Protein Dipole Langevin Dipoles (PDLD/S) method within the framework of the Linear Response Approximation (LRA). This is done by evaluating the interactions between ionized residues in the reaction center of Rhodobacter sphaeroides, while taking into account the protein reorganization energy. It is found that an explicit consideration of the protein relaxation leads to a significant increase in epsilon(eff) and that semimicroscopic models that do not take this relaxation into account force one to use a large value for the so-called "protein dielectric constant," epsilon(p), of the Poisson-Boltzmann model or for the corresponding epsilon(in) in the PDLD/S model. An additional increase in epsilon(eff) is expected from the reorganization of ionized residues and from changes in the degree of water penetration. This finding provides further support for the idea that epsilon(in) (or epsilon(p)) represents contributions that are not considered explicitly. The present study also provides a systematic illustration of the nature of epsilon(eff), supporting our previously reported view that charge-charge interactions correspond to a large value of this "dielectric constant," even in protein interiors. It is also pointed out that epsilon(eff) for the interaction between ionizable groups in proteins is very different from the effective dielectric constant, epsilon'(eff), that determines the free energy of ion pairs in proteins (epsilon'(eff) reflects the effect of preoriented protein dipoles). Finally, the problems associated with the search for a general epsilon(in) are discussed. It is clarified that the epsilon(in) that reproduces the effect of protein relaxation on charge-charge interaction is not equal to the epsilon(in) that reproduces the corresponding effect upon formation of individual charges. This reflects fundamental inconsistencies in attempts to cast microscopic concepts in a macroscopic model. Thus one should either use a large epsilon(in) for charge-charge interactions and a small epsilon(in) for charge-dipole interactions or consider the protein relaxation microscopically.     

Synergistic extraction of rare earth by mixtures of 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester and di-（2-ethylhexyl） phosphoric acid from sulfuric acid medium

The extraction of Nd^3＋ and Sm^3＋, including the extraction and stripping capability as well as the separation effect of Nd^3＋ or Sm^3＋, from a sulfuric acid medium, by mixtures of di-（2-ethylhexyl） phosphoric acid （HDEHP, H2A2（0）） and 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester （HEH/EHP, H2L2（0）） were studied. The distribution ratios and synergistic coefficients of Nd^3＋ and Sm^3＋ in different acidities were also determined. A synergistic extractive effect was found when HDEHP and HEH/EHP were used as mixed extractants for Sm^3＋ or Nd^3＋. The chemical compositions of the extracted complex were determined as Nd.（HA2）2-HL2 and Sm.（HA2）2-HL2. The extraction equilibrium constants, enthalpy change, and entropy change of the extraction reaction were also determined.     

The extraction of iron(III) from aqueous acid solutions by di(2-ethylhexyl)phosphoric acid

The extraction of iron(III) from aqueous solutions containing sulphuric, hydrochloric and nitric acids by di(2-ethylhexyl)phosphoric acid (DEHPA) in kerosene has been investigated under different conditions. As a result, it is found that although extraction is dominated by an ion-exchange reaction, the rate of iron(III) extraction from sulphuric acid solutions to reach equilibrium is relatively slow in comparison with that from hydrochloric or nitric acid solutions. In the extraction from aqueous solutions containing hydrochloric or nitric acid, however, the DEHPA combines with iron(III) according to the solvating reaction at higher aqueous acidity. From studies on the rate of the extraction from sulphuric acid solutions, examined under non-equilibrium, it is confirmed that dependencies of extraction rate on hydrogen ion and DEHPA concentrations are in the first and inverse first orders, respectively. The hydrolyzed species is considered to interpret the extraction mechanism in this system.     

Bis(acetato)bis(1-methyl-4,5-diphenylimidazole)copper(II): preparation, characterization, crystal structure, DNA strand breakage and cytogenetic effect

The preparation, characterization and antitumour properties of the complex [Cu(O2CMe)2L2] (1), where L = 1-methyl-4,5-diphenylimidazole, are described. The crystal structure of 1 (triclinic, space group P1, a = 6.743(1), b = 8.006(1), c = 15.898(1) A, alpha = 102.87(1), beta = 101.10(1), gamma = 76.76(1) degree, Z = 1) has been determined (R = 0.0254, Rw = 0.0275). In the centrosymmetric complex the copper ion is in an essentially square planar environment consisting of two pyridine-type imidazole nitrogen atoms and an oxygen atom from each acetate ligand; the second oxygen atoms of the carboxylate functionalities are involved in weak interactions with the metal completing the coordination to a very distorted tetragonal bipyramid. Complex 1 has been also characterized by elemental analyses, thermal methods, variable-temperature magnetic susceptibility and spectroscopic (IR and far-IR, FT-Raman, UV/VIS, EPR) techniques. The effect of the complex on the in vitro DNA strand breakage was examined. It was found that 1 causes degradation on the linearized pKS DNA, ds and ss DNA. High concentrations of this Cu(II) complex cause scissions on the relaxed and the supercoiled DNA. Furthermore, the in vivo cytogenic effect of 1 was examined on human lymphocyte cells. This study presents indications that 1 could have some relevance in the treatment of tumour cell lines. An orbital interpretation of the interaction of 1 with the DNA bases is proposed.     

The solvent extraction of lead from chloride solutions using di(2-ethylhexyl)phosphoric acid

Lead has been extracted from chloride solutions into kerosene containing excess di(2-ethylhexyl)phosphoric acid, using various concentrations of metal and extractant. Extraction proceeded readily, but the results indicated that 1.6 hydrogen ions were exchanged per atom of lead extracted, rather than 2.0 as would be expected for a divalent metal ion. Extraction was unaffected by metal concentration over the range studied (0.1–1.0 g l^?1), and the results were highly consistent. The unique log D vs. pH relation allowed simple collection of data for contact stage evaluation by rearrangement of the familiar solvent extraction equations and use of empirically derived constants. An S-shaped extraction isotherm resulted, which limits the ease with which aqueous lead concentrations may be reduced by extraction with di(2-ethylhexyl)phosphoric acid.