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PubMedDate not supplied

Reduction of arsenic uptake by lettuce with ferrous sulfate applied to contaminated soil.

Soil contamination by arsenic (As) presents a hazard in many countries and there is a need for techniques to minimize As uptake by plants. A proposed in situ remediation method was tested by growing lettuce (Lactuca sativa L. cv. Kermit) in a greenhouse pot experiment on soil that contained 577 mg As kg(-1), taken from a former As smelter site. All combinations of iron (Fe) oxides, at concentrations of 0.00, 0.22, 0.54, and 1.09% (w/w), and lime, at concentrations of 0.00, 0.27, 0.68, and 1.36% (w/w), were tested in a factorial design. To create the treatments, field-moist soil, commercial-grade FeSO4, and ground agricultural lime were mixed and stored for one week, allowing Fe oxides to precipitate. Iron oxides gave highly significant (P < 0.001) reductions in lettuce As concentrations, down to 11% of the lettuce As concentration for untreated soil. For the Fe oxides and lime treatment combinations where soil pH was maintained nearly constant, the lettuce As concentration declined in an exponential relationship with increasing FeSO4 application rate and lettuce yield was almost unchanged. Iron oxides applied at a concentration of 1.09% did not give significantly lower lettuce As concentrations than the 0.54% treatment. Simultaneous addition of lime with FeSO4, was essential. Ferrous sulfate with insufficient lime lowered soil pH and caused mobilization of Al, Ba, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Sr, and Zn. At the highest Fe oxide to lime ratios, Mn toxicity caused severe yield loss.

Agriculture↗
PubMedDate not supplied

Adsorption and transport of arsenic(V) in experimental subsurface systems.

The adsorption and transport of As(V) in a heterogeneous, iron oxide-containing soil was investigated in batch and column laboratory experiments. The As(V) adsorbed rapidly to the soil over the first 48 h, but continued to adsorb slowly over the next several weeks, clearly indicating the potential for rate-limited transport. The equilibrium As(V) adsorption isotherm was markedly nonlinear, further indicating the potential for nonideal transport. A model developed for the adsorption of As(V) to hydrous ferric oxide (HFO) was able to predict the pH-dependent adsorption of As(V) to the soil in batch experiments within 0.116 to 0.726 root mean square error (RMSE). Arsenic(V) was significantly retarded in column transport experiments. The column transport experiments were modeled using the one-dimensional advection-dispersion equation, considering both linear and nonlinear adsorption equilibrium. Although the nonlinear local equilibrium model (NLLE, RMSE = 0.273) predicted the data better than the linear local equilibrium model (LLE, RMSE = 0.317), As(V) breakthrough occurred more rapidly than predicted by either model due to adsorption nonequilibrium. However, due to the presence of an irreversible or slowly desorbing fraction, the peak aqueous As(V) concentration (0.624 mg L(-1)) and the total amount of As(V) recovered (44%) was lower than predicted based on the two equilibrium models (NLLE and LLE). For the conditions used in this study [1 mg L(-1) As(V), pH 4.5 and 9,0-0.25 mM PO4, 0.53-1.6 cm min(-1) pore water velocity], the effect on As(V) mobility and recovery increased in the order pH < pore water velocity < PO4.

Adsorption↗
PubMedDate not supplied

The cytochochleogram in atoxyl-treated guinea pigs.

The earliest atoxyl induced changes in the cochlea appeared in the upper and medial parts of the 4th coil, whence the changes spread progressively downwards towards the round window, the extent of the changes depending on the amount of atoxyl administered and the duration of the treatment. The inner hair cells were more resistant to the effects of atoxyl than the outer hair cells which were affected first. The sensory cells in the 2nd and 3rd rows appeared more sensitive than the outer hair cells in the first row.

Aminobenzoates↗
PubMedDate not supplied

Experimentally (atoxyl) induced ampullar degeneration and damage to the maculae utriculi.

Atoxyl administration to guinea pigs may cause vesicular degeneration of both the secretory and the sensory regions of the cristae ampullares and macula utriculi. Some of the severely damaged secretory cells were even expelled from the surface into the endolymphatic space. The nerve chalices of type I hair cells disintegrated. The degeneration of the secretory region will thus block the endolymph circulation and the electrolyte balance is likely to collapse. Whether hair cell degeneration can best be explained on this basis (indirect atoxyl effect) or by a direct action of atoxyl on the hair cells and the nerve chalices of type I hair cells is discussed.

Aniline Compounds↗
PubMedDate not supplied

Reversible and irreversible changes of the stria vascularis. An evaluation of the effects of ethacrynic acid separately and in combination with atoxyl.

The morphological changes in the cochlea following administration of ethacrynic acid occur initially in the stria vascularis of the basal coils as an increased intracellular vesiculation of the marginal cells followed by inter- and intracellular oedema in the intermediate cell layer. The combined administration of ethacrynic acid and atoxyl (individual doses) can cause irreversible damage to the cochlear hair cells and the stria vascularis, while the administration of each of them separately in the same low dose did not cause hair cell degeneration or persistent morphological changes of the stria vascularis. An increased penetration of atoxyl into the cochlea is likely to occur due to the ethacrynic acid-induced changes in the permeability of the endolymphatic partition so that the earlier known penetration of atoxyl into the cochlea is increased.

Aniline Compounds↗
PubMed2000

A laser scanning confocal microscopy method. Simultaneous detection of intracellular Ca2+ and apoptosis using Fluo-3 and Hoechst 33342.

OBJECTIVE: To develop a simple and direct method to simultaneously determine apoptotic cells from a treated population of cells and detect the changes of intracellular Ca2+ in these apoptotic cells, in particular single ones, by confocal microscopy. STUDY DESIGN: MGC-803 cells treated with As2O3 were used as the double-staining cell model with Hoechst 33342 as a DNA probe and Fluo-3AM as a Ca2+ indicator. MGC-803 cell apoptosis induced by As2O3 was first demonstrated by DNA ladder in gel electrophoresis. Based on the difference in DNA stainability with Hoechst 33342 and corresponding fluorescence intensity between live and apoptotic cells, apoptotic cells and the changes in intracellular Ca2+ were detected at the same time by confocal microscopy. No necrotic cells in the group treated with As2O3 were found by the trypan blue exclusion test. RESULTS: The results from confocal microscope detection showed that intact and apoptotic cells were successfully recognized and the changes of intracellular Ca2+ in apoptotic and intact cells were simultaneously detected in the same sample. CONCLUSION: We provided a useful method to exactly detect changes in intracellular Ca2+ in apoptotic cells, especially in single ones, by confocal microscopy and to exclude the artifact effect of necrotic and intact cells.

Aniline Compounds↗
PubMed1975

Role of the clotting system in cell-mediated hypersensitivity. II. Kinetics of fibrinogen/fibrin accumulation and vascular permeability changes in tuberculin and cutaneous basophil hypersensitivity reactions.

Radioactive tracers and immunofluorescence were employed to detect and quantitate fibrinogen/fibrin deposition in two types of cell-mediated hypersensitivity reactions in the guinea pig. Classic delayed hypersensitivity (DH) reactions to Old Tuberculin and to the azobenzenearsonate hapten were characterized by a progressive increase in the fibrinogen (125-I-HF) content which exceeded that of the albumin tracer (131-I-HSA) and paralleled the development of induration and erythema. Accumulation of 125-I-HF could be related both to increased vascular permeability to 125-I-HF and, more specifically, to retarded efflux of extra vascular 125-I-HF from tuberculin reaction sites. Warfarin inhibited 125-I-HF accumulation and the formation of urea-insoluble 125-I-HF (cross-linked fibrin) as well as induration in tuberculin reactions. Immunofluorescence studies revealed the site of Fib deposition to be extravascular, among the connective tissue fibers of the dermis, similar to that in DH reactions in man. In contrast, little 125-I-HF accumulated in cell-mediated reactions rich in basophils--cutaneous basophil hypersensitivity (CBH) reactions to keyhole limpet hemocyanin, ovalbumin, and dinitrochlorobenzene--due in part to less vascular leakage of macromolecules and to decreased formation of urea-insoluble fibrin. By immunofluorescence Fib deposits were found in CBH reactions in a pattern similar to that in DH reactions, but the intensity of staining was appreciably less. Thus, fibrin accumulation further distinguishes DH from CBH reactions and is very likely responsible for the induration characteristic of DH reactions.

Animals↗
PubMed2001

[Removal of arsenic from dispersed drinking water by iron oxide-coated sand].

The iron oxide-coated sand(IOCS) was developed by treating normal river sand with molysite and investigated by batch, column tests and autoptic experiment to evaluate it's ability of eliminating arsenic from dispersed drinking water. The results showed that IOCS was relatively stable and can be seen iron oxide distributedly patched the surface of sand by scan electron microscope. IOCS needn't any activation pretreatment. It reached the maximum adsorption within 30-60 min. The removal percentage of arsenate was decreased but the one of arsenite had little change when the pH varied from 5 to 9. And the arsenic adsorption matched the Langmuir isotherm. In 5 circles of runs, it treated 408-426 (arsenite) beds and 390-412(arsenate) beds volume of water with 75 g(50 ml) IOCS respectively when the influent arsenic concentration was 1.0 mg.L-1. And the arsenic percentage recovery was above 94% when regenerating the IOCS by 0.2 mol.L-1 NaOH. The home simulation unit contained IOCS 3.0 kg produced 209 L and 198 L, 196 L and 185 L of water when the influent arsenate or arsenite concentration was 1.0 mg.L-1, and 200 L arsenic free water with the influent arsenic 0.202-1.733 mg.L-1 during the field experimental period. The water quality was not affected by the adsorbent. With low-cost and simple operation, the IOCS should be a promising novel medium for arsenic removal in dispersed drinking water.

Adsorption↗
PubMed1976

Arsanilic acid-induced blindness in swine: electroretinographic and visually evoked responses.

Arsanilic acid (1,000 ppm) caused blindness in pigs within 25 to 30 days. The visually evoked response was "nonrecordable" in blind pigs, but was consistently recordable in normal pigs. The electroretinographic response was recordable in both normal and blind pigs, and significant differences were not apparent between results of tests of the 2 groups. Optic disk atrophy was noted ophthalmoscopically; lesions of the optic nerve are probably responsible for the nonrecordable visually evoked response.

Aniline Compounds↗
PubMed2003

[Arsenic adsorption by magnetic adsorbent CuFe2O4].

By the fact that Cu(II) and Fe(III) have strong affinity toward inorganic arsenic, the present paper reported the preparation of the magnetic adsorbent CuFe2O4 for the removal of arsenic. This adsorbent was composed with Cu(II) and Fe(III) oxides and can be recovered by magnetic separation technique. The characterization and the arsenic adsorption properties of the magnetic adsorbent were also studied. The sorption capacity was related to the pH of arsenic containing solution and the adsorption was more efficient for removing arsenic from acid and neutral solutions. As(V) was found to be more strongly adsorbed than As(III) on the adsorbent, and its adsorption capacity was 10 mg/g at equilibrium concentration of 10 micrograms/L (pH 3.5-6.5). Arsenic adsorption was not influenced by the presence of chloride and phosphate, but slightly influenced by sulfate at 10-20 times concentration of arsenic. As(V) desorption was performed more efficiently than As(III) desorption using 0.1 mol/L NaOH, which was the result of the different adsorption mechanism for the two arsenic species on adsorbent.

Adsorption↗