Effects of short-term benzene administration on bone marrow cell cycle kinetics in the rat.
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Animals↗
Biomedical subjects
R D Irons
Publications and source records attributed to R D Irons.
Benzene disposition in the rat after exposure by inhalation.
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Animals↗
Partial saturation of rat liver Cd-binding proteins by Cd2+ in vivo.
Liver Cd-binding proteins (Cd-BP) were isolated from rats chronically treated with 109Cd-labeled CdCl2 for ten days. Fractions purified using Sephadex G-75 and DEAE-Sephadex were characterized and found to be similar to those isolated by other investigators. Cd-binding was not saturated in any of the preparations and significant amounts of Cu and Zn were also found bound to the proteins. The percentage of saturation of Cd-BP1, and Cd-BP2 was independently determined by atomic absorption spectrometry and spectroscopy at 254 nm. These results indicate that the fraction of binding sites unoccupied by Cd on Cd-BP approaches 20% in vivo.
Amino Acids↗
Isolation of a non-thionein copper-binding protein from liver of copper-injected rats.
1. The characterization of a low molecular weight, non-thionein, Cu-binding protein isolated from rat liver is reported. The protein was isolated following chronic administration of Cu(NO3)2 using a combination of Sephadex G75 and Sephadex DEAE A-25 chromatography. The protein did not bind to fully equilibrated Sephadex DEAE which formed the basis of the isolation procedure. 2. The final protein pereparation was found to be homogenous by a variety of electrophoretic techniques and was distinguished from metallothionein on the basis of its behaviour on ion exhcange and electrophoretic systems, spectral properties, and amino acid composition and metal content. It contains 6.8% cysteine and was found to bind Cu in a ration of 1.5:1 based on a molecular weight of 11 000. 3. These results confirm the necessity to use techniques other than gel filtration alone to obtain adequate separation of low molecular weight metal-binding protein fractions.
Amino Acids↗
Cytochemical methods for copper. Semiquantitative screening procedure for identification of abnormal copper levels in liver.
Three previously described histochemical methods for the localization of copper were examined for applicability in the semiquantitative evaluation copper levels in human tissue. Liver tissue obtained at autopsy was stained using dimethylaminobenzylidene rhodanine, rubeanic acid, and diethyldithiocarbamate procedures. The effects of method and time of fixation, staining, incubation time, and variations in procedures were evaluated. Copper levels in tissues examined were determined using atomic absorption spectroscopy. Each staining method was evaluated for sensitivity, reproducibility, and linearity. The rhodanine method was found to produce the most reproducible results, and a linear relationship between microscopical evaluation of the stain and actual tissue copper levels was observed. It was concluded that the rhodanine copper method is applicable for the semi-quantitative evaluation of tissue copper and provides a satisfactory screening method for the identification of abnormal tissue copper levels.
Copper↗
Prevention by copper of cadmium sequestration by metallothionein in liver.
Following chronic CdCl2 administration to rats, more than 98% of the metal in liver supernatant is bound to the low molecular weight binding protein, metallothionein. Simultaneous administration of high doses of Cd and copper salts result in an increase in toxicity which is accompanied by a failure of Cd sequestration by metallothionein in vivo. This may be due to an aggregation of metallothionein which has been observed in the presence of copper in vitro.
Animals↗
Energy-dispersive x-ray fluorescence spectroscopy and inductively coupled plasma emission spectrometry evaluated for multielement analysis in complex biological matrices.
Energy-dispersive x-ray spectroscopy and inductively coupled plasma emission spectrometry were evaluated as methods for routine multielement analysis of biological material. Standard samples included Standard Reference Materials (National Bureau of Standards), compounded mixtures, and supplements that provided a wide range of elemental concentrations for analysis. Elements included in this study were Zn, Pb, Ni, Mn, Fe, Mg, Cu, Ca, As, Se, Br, Rb, and Sr. Standards were analyzed as unknowns by participating laboratories. The two methods were evaluated for sensitivity, precision, and accuracy, and the results compared to those obtained for atomic absorption spectrometric analysis of identical standard unknowns. Both methods compared favorably and both were determined to be highly reliable for such an application. Advantages and disadvantages of each method are compared and discussed.
Animals↗