Palliative treatment of prostatic cancer with radioactive colloidal chromic phosphate: three years experience and results.
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Chromium↗
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Treatment of prostatic carcinoma with radioactive colloidal chromic phosphate (p32); a preliminary report.
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Chromium Compounds↗
Cytotoxicity of four root end filling materials.
Leakage and scanning electron microscopic studies have shown that a mineral trioxide aggregate (MTA) used as root end filling material permits significantly less leakage and has better adaptation than other commonly used root end filling materials. Because these materials are in contact with the periradicular tissues, their cytotoxicity should be evaluated before in vivo tests. Using the agar overlay and radiochromium methods, the cytotoxicity of amalgam, Super EBA, IRM, and the MTA was evaluated. Statistical analysis of the data from the agar overlay technique shows that freshly mixed and set amalgam were significantly less toxic than the rest of tested materials (p< 0.00005). Fresh and set MTA ranked second when tested for cytotoxicity with this technique. Similar statistical tests revealed a significant statistical difference between the toxicity of freshly mixed and set materials after 24 h of incubation with radiochromium-labeled mouse L929 cells. The degree of cytotoxicity of fresh and set materials was MTA least toxic followed by amalgam, Super EBA, and IRM. Based on the results of the cell culture methods used in this study it appears that MTA is a potential root end filling material and warrants further in vivo evaluations.
Agar↗
DNA strand breaks (comet assay) and embryo development effects in grass shrimp (Palaemonetes pugio) embryos after exposure to genotoxicants.
Grass shrimp embryos develop in egg sacs (stages 1-10) attached to the female for 14-20 days after which they 'hatch' from the egg sacs into a swimming zoea stage (stage 11). Until they emerge from the egg sacs, embryos depend on lipids and lipovitellin stored within the egg. The percent of embryos which hatch after exposure to toxicants relative to controls was the basis of an embryo development assay. Exposure of embryos to chromium(III) chloride, sodium chromate, mercuric chloride, and 2-methyl-1,2-naphthoquinone (MNQ) resulted in a reduced hatching rate. In addition to effects on embryo development, DNA strand damage tests were carried out on contaminant-exposed embryos, using the single-cell electrophoresis method often referred to as comet assay. Development of stage 4 embryos was more affected by MNQ exposure than stage 7 embryos. The hatching rates of stages 4 and 7 embryos exposed to MNQ (172 micrograms/l) were 0 and 90%, respectively. DNA strand damage, measured as DNA tail moments, were 3.4 and 4.4, respectively. Thus, exposure of an early embryo stage to MNQ prevented full embryo development while development of later embryo stages was not affected. It may be that the DNA repair systems are more efficient in later embryo stages than in early stages and thus DNA damaged in the early stages affects development.
Animals↗
The effect of Ca/P concentration and temperature of simulated body fluid on the growth of hydroxyapatite coating on alkali-treated 316L stainless steel.
316L-SS is one of the important materials both in orthopaedics and dentistry for bone screw/plate, intra-medullary rod, fixation wire, HIP joint, and knee joint. However, the biocompatibility and bone-bonding ability troubled researches for years. In the study, a simple chemical method was tried so as to establish and induce a bioactive HA layer on the surface of 316L stainless steel. When the metallic substrates treated with 10 M NaOH aqueous solution and subsequently heated at 600 degrees C, a thin sodium chromium oxide layer was formed on the surfaces as the linking layer for HA and 316L-SS. After 316L-SS treated with alkali solution, it would soak into a simulated body fluid with higher concentration of calcium and phosphorous ions to increase the possibility of nucleation of HA. However, the iron oxide and iron chromium oxides were formed on the surface when calcium and phosphorous ions increased. This resulted in loosening the HA layer. When the alkali-treated 316L-SS was soaked into SBF at a temperature of 80 degrees C, it could form a dense and uniform bone-like hydroxyapatite layer on the surface. In the research, the mechanism of the formation of sodium chromium oxide and HA would also be described by the analysis of X-ray diffractometer, scanning electron microscope, energy-dispersion spectrophotometer, and Fourier transformation infrared.
Alkalies↗
The alkaline comet test on plant cells: a new genotoxicity test for DNA strand breaks in Vicia faba root cells.
The alkaline comet assay (single cell gel electrophoresis assay) is a sensitive method for the detection of DNA damage. This paper describes the first application of this assay to plant cells for genotoxicological assessment. Germinating Vicia faba (field bean) seedlings were kept in water with either methyl methanesulfonate (MMS), ethyl methanesulfonate (EMS), mitomycin C (MMC), cycloheximide (CH), cadmium chloride (CdCl2), potassium dichromate (K2Cr2O7), or chromium trichloride (CrCl3). Nuclei were isolated from the root cells and evaluated for the extent of DNA migration. With the exception of cycloheximide, all agents induced a significant increase in DNA migration. These results indicate that the comet assay may be a valuable tool for monitoring DNA damage in plant systems. However, there was a significant heterogeneity in the extent of DNA migration within and between seedlings, which may be intrinsic to the assay or indicative of sampling problems.
Cadmium↗
Chromium transport, oxidation, and adsorption in manganese-coated sand.
We examine how the processes of advection, dispersion, oxidation-reduction, and adsorption combine to affect the transport of chromium through columns packed with pyrolusite (beta-MnO2)-coated sand. We find that beta-MnO2 effectively oxidizes Cr(III) to Cr(VI) and that the extent of oxidation is sensitive to changes in pH, pore water velocity, and influent concentrations of Cr(III). Cr(III) oxidation rates, although initially high, decline well before the supply of beta-MnO2 is depleted, suggesting that a reaction product inhibits the conversion of Cr(III) to Cr(VI). Rate-limited reactions govern the weak adsorption of each chromium species, with Cr(III) adsorption varying directly with pH and Cr(VI) adsorption varying inversely with pH. The breakthrough data on chromium transport can be matched closely by calculations of a simple model that accounts for (1) advective-dispersive transport of Cr(III), Cr(VI), and dissolved oxygen, (2) first-order kinetics adsorption of the reduced and oxidized chromium species, and (3) nonlinear rate-limited oxidation of Cr(III) to Cr(VI). Our work supplements the limited database on the transport of redox-sensitive metals in porous media and provides a means for quantifying the coupled processes that contribute to this transport.
Adsorption↗
Cu, Cr and As distribution in soils adjacent to pressure-treated decks, fences and poles.
Chromated copper arsenate (CCA)-treated wood has been widely used in the Southeastern United States to protect wood products from microbial and fungal decay. The aims of this study were to (1). determine the distribution of arsenic (As), chromium (Cr), and copper (Cu), in soils surrounding CCA-treated wood structures such as decks, fences and poles; and (2). evaluate the impacts of these structures on As, Cr and Cu loading of the soils. Profile and lateral soil samples were collected under CCA-treated decks and adjacent to poles and fences. The results showed elevation of As, Cr and Cu concentrations close to and under the structures, with mean As concentrations as high as 23 mg x kg(-1) close to utility poles compared with less than 3 mg x kg (-1) at distances of about 1.5 m away. Concentrations of As, Cr, and Cu decreased with depth in areas close to CCA-treated poles. However, these results were only apparent in relatively new structures. A combination of weathering and leaching with time may have reduced the impact in older poles. Increased concentrations of As, Cu and Cr were also observed close to CCA-treated decks and fences, with age showing a similar impact. These results are helpful for CCA-treated wood product users to determine the safe use of these structures.
Arsenates↗
Cytotoxicity and oxidative mechanisms of different forms of chromium.
Chromium exists mostly in two valence states in nature: hexavalent chromium [chromium(VI)] and trivalent chromium [chromium(III)]. Chromium(VI) is commonly used in industrial chrome plating, welding, painting, metal finishes, steel manufacturing, alloy, cast iron and wood treatment, and is a proven toxin, mutagen and carcinogen. The mechanistic cytotoxicity of chromium(VI) is not completely understood, however, a large number of studies demonstrated that chromium(VI) induces oxidative stress, DNA damage, apoptotic cell death and altered gene expression. Conversely, chromium(III) is essential for proper insulin function and is required for normal protein, fat and carbohydrate metabolism, and is acknowledged as a dietary supplement. In this paper, comparative concentration- and time-dependent effects of chromium(VI) and chromium(III) were demonstrated on increased production of reactive oxygen species (ROS) and lipid peroxidation, enhanced excretion of urinary lipid metabolites, DNA fragmentation and apoptotic cell death in both in vitro and in vivo models. Chromium(VI) demonstrated significantly higher toxicity as compared with chromium(III). To evaluate the role of p53 gene, the dose-dependent effects of chromium(VI) were assessed in female C57BL/6Ntac and p53-deficient C57BL/6TSG p53 mice on enhanced production of ROS, lipid peroxidation and DNA fragmentation in hepatic and brain tissues. Chromium(VI) induced more pronounced oxidative damage in multiple target organs in p53 deficient mice. Comparative studies of chromium(III) picolinate and niacin-bound chromium(III), two popular dietary supplements, reveal that chromium(III) picolinate produces significantly more oxidative stress and DNA damage. Studies have implicated the toxicity of chromium picolinate in renal impairment, skin blisters and pustules, anemia, hemolysis, tissue edema, liver dysfunction; neuronal cell injury, impaired cognitive, perceptual and motor activity; enhanced production of hydroxyl radicals, chromosomal aberration, depletion of antioxidant enzymes, and DNA damage. Recently, chromium picolinate has been shown to be mutagenic and picolinic acid moiety appears to be responsible as studies show that picolinic acid alone is clastogenic. Niacin-bound chromium(III) has been demonstrated to be more bioavailable and efficacious and no toxicity has been reported. In summary, these studies demonstrate that a cascade of cellular events including oxidative stress, genomic DNA damage and modulation of apoptotic regulatory gene p53 are involved in chromium(VI)-induced toxicity and carcinogenesis. The safety of chromium(III) is largely dependent on the ligand, and adequate clinical studies are warranted to demonstrate the safety and efficacy of chromium(III) for human consumption.
Animals↗
Microbial stability evaluation of cement-based waste forms at different waste to cement ratio.
An evaluation of the effect of differences in chromium nitrate to cement ratio on the microbial stability of a chromium nitrate/cement waste form, as reflected in the leaching of chromium, calcium, magnesium and aluminum; was carried out in this study. An increase in the proportion of chromium in the waste form from 4.8 to 8.7% had no noticeable effect on microbial stability, with the total chromium leached essentially unchanged. Further increases in the proportion of chromium in the waste form from 8.7 to 10.7%, and from 10.7 to 15.9% resulted in a substantial decrease in microbial stability, with 3-fold and 1.3-fold increase in the total chromium leached, respectively, observed. For calcium, increases in the chromium proportion were accompanied with increases in the total calcium leached even though the increases were not in direct proportion to the increases in chromium proportion. For magnesium and aluminum, increases in the proportion of chromium within the range 4.8-10.7% were accompanied with increases in the total respective metals leached, with minor variation for each metal. On the whole, the maximum percentage chromium leached from the different waste forms was substantially lower than those of the other metals.
Aluminum↗
Behaviour of metals under the conditions of roasting MSW incinerator fly ash with chlorinating agents.
A total elemental analysis was performed on a municipal solid waste (MSW) fly ash sample, before and after it was treated at 1000 degrees C, to reveal the metal distribution between the volatile matter and the ash residue. Metals such as Pb, Zn, Cd, and to a lesser degree, Cr, Mn and Ni, were volatilized. Addition of chlorinating agents generally increased the volatility of certain elements. More acid resistant compounds were formed in the ash residue after the heat treatment using CaCl2 as a chlorinating agent. The efficiencies of volatilization of the metals, using Cl2 as a chlorinating agent, were generally higher compared with using CaCl2. However, CaCl2 was found to be a more selective chlorinating agent for volatilizing the heavy metals of concern, i.e., Pb, Cd, Zn and Cu. The efficiencies of volatilization of the recovered metals were approximately proportional to their standard free-energy changes (delta G(o) for the corresponding chlorination reactions.
Air Pollutants↗
ELNES investigations of the oxygen K-edge in spinels.
The results of a systematic study of the oxygen K-edge electron energy-loss spectroscopy (ELNES) from a series of aluminium- and chromium-containing spinels are presented. Extra fine structure in the region up to 10 eV above the edge onset is observed for the chromium-containing compounds and is assigned to transitions to states created by mixing of oxygen 2p and metal 3d orbitals. The experimental data has been simulated using the multiple scattering code, FEFF8. Good agreement was obtained in the case of magnesium aluminate, but relatively poor agreement was obtained in the case of the chromites. The possible fingerprints in the oxygen K-edge ELNES corresponding to a high degree of inversion the spinel structure and to a tetragonal distortion of the cubic structure are discussed.
Journal Article↗
Chromium(III) hydrolytic oligomers: their relevance to protein binding.
The nature of chromium(III) complexes has been found to show a profound influence in its interaction with collagen. The hydrothermal stability of rat tail tendon (RTT) fibres treated with dimeric, trimeric and tetrameric species of chromium(III) has been found to be 102, 87 and 68 degrees C, while that of native RTT is 62 degrees C. This shows that the efficiency of crosslinking of collagen by chromium(III) species is dimeric > trimeric > tetrameric. This order of stabilisation is again confirmed by cyanogen bromide (CNBr) cleavage of RTT collagen treated with dimeric, trimeric and tetrameric chromium(III) species. CNBr has been found to cleave the collagen treated with tetrameric chromium(III) species extensively. On the other hand, dimer-treated collagen does not undergo any cleavage on CNBr treatment. The equilibrium constants for the reaction of a nucleophile like NCS(-) to the dimeric, trimeric and tetrameric species of chromium(III) have been found to be 15.7+/-0.1, 14.6+/-0.1 and 1.2+/-0.1 M(-1), respectively. These equilibrium constant values reflect the relative thermodynamic stability of the chromium(III) species-nucleophile complex. The low stabilising effect of the tetrameric species can be traced to its low thermodynamic affinity for nucleophiles.
Animals↗
Chromate-induced human erythrocytes haemoglobin oxidation and peroxidation: influence of vitamin E, vitamin C, salicylate, deferoxamine, and N-ethylmaleimide.
In order to attenuate or to prevent chromate-induced human erythrocytes injury, the influence of vitamin E, vitamin C, salicylate, deferoxamine, and N-ethylmaleimide on chromate-induced human erythrocytes haemoglobin oxidation and peroxidation were investigated. It was observed that pretreatment of human erythrocytes with vitamin E (20 microM), vitamin C (1 mM), salicylate (3 mM), and deferoxamine (4 mM) significantly increased (P=0.0001) chromate-induced human erythrocytes haemoglobin oxidation in a time dependent manner, while it was significantly decreased (P=0.0001) by pretreatment with N-ethylmaleimide (1 mM). In contrast, pretreatment of human erythrocytes with deferoxamine (4 mM) immediately inhibited (P=0.0001) chromate-induced human erythrocytes peroxidation, while it was significantly increased (P=0.0001) by pretreatment with N-ethylmaleimide (1 mM) during the first 4 h of cells exposition to chromate. For time periods superior to 6 h pretreatment with N-ethylmaleimide (1 mM) significantly decreased (P=0.0001) chromate-induced human erythrocytes peroxidation. It was concluded that care must be taken as these drugs are used to prevent against toxicity induced by chromium(VI) compounds.
Ascorbic Acid↗
Uptake and tissue distribution of chromium(III) in mice after a single intraperitoneal or subcutaneous administration.
The tissue levels of chromium were followed after single intraperitoneal or subcutaneous injection of 1 mmol CrCl3/kg body wt. in Swiss male mice. Blood levels were similar after both treatment modes, with half-lives of 31-41 h. Organs not directly exposed by i.p. treatment contained similar amounts in the two groups, with kidneys > lungs > heart > brain. However, after i.p. treatment peritoneal organs (liver, spleen, pancreas and testis) had 40- to 200-fold more chromium compared with s.c. Assay of subsurface liver tissue and of testes removed via the scrotum indicated infiltration of the organs, rather than surface adsorption, of peritoneal chromium. Relative chromium concentrations after i.p. treatment were liver > pancreas = spleen > testis and after s.c. liver > spleen > testis > pancreas. Thus, s.c. treatment with CrCl3 is as effective as i.p. in terms of absorption into the blood. Treatment i.p., leading to direct uptake into peritoneal organs, is an effective way to deliver high chromium doses to these organs, but does not model likely human exposure.
Animals↗
Carcinogenicity of metal compounds: possible role of DNA repair inhibition.
Compounds of chromium, nickel, cadmium, cobalt and arsenic are well-known carcinogens. However, their mode of action is still not fully understood, since, with the exception of chromium(VI), direct genotoxic effects are rather weak and/or restricted to comparatively high concentrations. However, current evidence suggests that DNA repair systems are very sensitive targets for nickel(II), cadmium(II), cobalt(II) and arsenic(III), leading to a diminished removal of endogenous DNA lesions and of DNA damage induced by environmental agents, which in turn may increase the risk of tumor formation. Nevertheless, the underlying mechanisms are quite different, depending for example on the ability of toxic metal ions to compete with magnesium ions or to displace zinc ions in zinc finger structures of DNA repair enzymes.
Animals↗
Immune-endocrine interactions in agricultural species: chromium and its effect on health and performance.
The purported performance-enhancing effects of supplemental Cr, as elaborated in studies focusing on beef and dairy cattle models of agricultural stress, affect both immune and endocrine pathways. Furthermore, interactions between the immune and endocrine systems, associated with the actions of insulin and cortisol, may be coordinated through the production of regulatory cytokines. Unlocking the mechanism of action of Cr as a useful farm animal management tool may provide further understanding of the health and performance ramifications of immune-endocrine interactions in agricultural species.
Acute-Phase Reaction↗
Microarray analysis of altered gene expression in the TM4 Sertoli-like cell line exposed to chromium(III) chloride.
Chromium(III) chloride is a common human exposure metal that is a preconceptional carcinogen in mice, although it enters cells poorly, and is non-toxic and non-carcinogenic in most biologic systems. An indirect effect on sperm is postulated, and this effect might be mediated through the testicular Sertoli cells that influence spermatogenesis. To test this possibility, we exposed mouse TM4 Sertoli-like cultured cells to 1mM CrCl(3) x 6H(2)O, a non-toxic dose, for 7 days and then extracted mRNA for microarray analysis. The chromium(III) chloride had modest effects on the expression of many genes, in the range of 1.5-2.3-fold. These effects provided an opportunity for development of statistical approaches for sifting microarray data in a situation where differences were small. Data were winnowed by screening for those ratios that fell outside the 99% confidence limits and/or represented a > or = 50% change in expression in the three comparison pairs. Fifty-two genes/clones were significant after the Bonferroni adjustment for multiple comparisons. The largest average increase was observed for the transcription factor Bach2, and this increase was confirmed by RT-PCR. The results show that Cr(III) has significant effects on gene expression in a Sertoli-like cell line.
Animals↗