Pesticides and toxic chemicals.
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Animals↗
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Results for “METALS, RADIOACTIVE”
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Continuous monitoring, automated analysis, and sampling procedures.
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Ammonia↗
Reversible inactivation of guanylate cyclase by mixed disulfide formation.
Highly purified preparations of guanylate cyclase from rat lung were inactivated by several disulfide compounds in a time- and dose-dependent manner. Cystamine and cystine were the most potent disulfides tested, but other compounds which contained the cysteamine moiety (NH2CH2CH2S-), including pantethine and oxidized coenzyme A, were also able to partially inactivate the enzyme. In addition to the decrease in basal activity (measured with either Mg2+-GTP or Mn2+-GTP), disulfide-inhibited enzyme was activated to a lesser extent by nitric oxide. Treatment with dithiothreitol or other reducing agents restored basal activity and increased the level of cGMP production following nitric oxide activation. Control enzyme samples exhibited a single GTP Km of 25 microM or 150 microM with Mn2+ or Mg2+, respectively. However, cystamine-treated enzyme showed these same Km values as well as an additional GTP Km of 2 to 3 microM using either metal ion as cofactor. When [35S]cystine was incubated with purified enzyme, radioactivity was incorporated into the trichloroacetic acid-precipitable protein, and the counts were released following dithiothreitol treatment. In addition, [35S]cystine-labeled enzyme co-migrated with native guanylate cyclase on nondenaturing polyacrylamide gels. These data indicate that mixed disulfides can be formed between guanylate cyclase and certain naturally occurring compounds, and that disulfide formation leads to a reversible loss of enzyme activity.
Animals↗
[Nutritional and toxicological impacts of administered inorganic tin for six months in rats (author's transl)].
An experimentation of intoxication by stannous chloride has been realized in the rat. Two groups of animals have been fed ad libitum, during six months, with a diet containing respectively 0,4 and 0,8 g of tin (SnCl2) for 100 g of dry food. By gamma radioactivity measurements (with 113Sn used as a tracer), it results that this metal does not practically clear the digestive barrier. All the treated animals are characterized by a ponderal evolution obviously lower than temoins. At the end of treatment, tin entails a significative diminution of hematocrit, hemoglobin and serous iron, particularly at the highest dose studied. The essential impact remains that tin induces a total irritation of gastro-intestinal tract, proved by histological investigations.
Animals↗
Peptide-based phosphoproteomics with immobilized metal ion chromatography.
The identification of protein phosphorylation sites has always been a challenging task, traditionally involving large amounts of radioactive phosphorus and high-performance liquid chromatography separation and Edman sequencing of phosphopeptides. The rapid development of mass spectrometric methods has advanced protein research significantly, and the identification of in vivo post-translational modifications of even rare proteins is now possible. Even with the new generation of machines, however, phosphopeptides do not lend themselves easily to mass spectrometric analysis. In complex mixtures of peptides, phosphopeptides are often difficult to detect because of suppression effects during ionization. This problem can be largely solved by affinity purification/enrichment of the phosphopeptides, and immobilized metal ion affinity chromatography (IMAC) on chelated Fe3+ or other metal ions has emerged as the simplest and most useful method. IMAC has been useful to identify several in vivo phosphorylation sites of individual proteins, but is easier to apply to complex mixtures. We describe a complete protocol as it has been used for Arabidopsis plasma membranes, and note where it can be adapted for soluble protein mixtures.
Arabidopsis↗
Mechanisms of enrichment of natural radioactivity along the beaches of the Camargue, France.
A field study was carried out along the Golfe du Lion, that focussed on the beaches of the Camargue, to locate the main areas where enriched U and Th are found, and to better understand the processes that concentrate radioactivity on beaches. Indeed enriched areas are observed on some Camargue beaches, where high-dose rates are recorded due to excess U and Th activity (>1000 Bq kg(-1)). The coastline was mapped by means of an aerial gamma survey and the results indicated that the main actinides deposits occurred in the Camargue area. This concentrating effect is possibly due to a greater sedimentary contribution from the River Rhone relative to other minor Mediterranean rivers. Across the along-shore profile, the variability in actinides observed at the eastern part of Beauduc spit is mainly explained by variations in heavy and light mineral contents. Such variability can be accounted for by redistribution of the sand caused by erosion/deposition processes occurring in the eastern part of the spit. Further parameters such as grain size and heavy minerals content were studied in connection with the distribution of U, Th and (40)K in the field at a more localised level (i.e. across-shore beach profile). The <200-micro m fraction contains more than 50% of the radioactivity and heavy minerals (especially zircon) are the main contributors to the high levels of external radiation. Therefore the enriched areas, where U and Th exceed 1000 Bq kg(-1), presumably result from the sorting of sand grains according to their size and density.
Background Radiation↗
Preparation, characterization and biological activity of Fe(III), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and UO(2)(II) complexes of new cyclodiphosph(V)azane of sulfaguanidine.
Novel hexachlorocyclodiphosph(V)azane of sulfaguanidine, H(4)L, l,3-[N'-amidino-sulfanilamide]-2,2,2,4,4,4-hexachlorocyclodiphosph(V)azane was prepared and its coordination behaviour towards the transition metal ions Fe(III), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and UO(2)(II) was studied. The structures of the isolated products are proposed based on elemental analyses, IR, UV-vis, (1)H NMR, mass spectra, reflectance, magnetic susceptibility measurements and thermogravimetric analysis (TGA). The hyperfine interactions in the isolated complex compounds were studied using 14.4keV gamma-ray from radioactive (57)Co (Mössbauer spectroscopy). The data show that the ligand are coordinated to the metal ions via the sulfonamide O and deprotonated NH atoms in an octahedral manner. The H(4)L ligand forms complexes of the general formulae [(MX(z))(2)(H(2)L)H(2)O)(n)] and [(FeSO(4))(2) (H(4)L) (H(2)O)(4)], where X=NO(3) in case of UO(2)(II) and Cl in case of Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II). The molar conductance data show that the complexes are non-electrolytes. The thermal behaviour of the complexes was studied and different thermodynamic parameters were calculated using Coats-Redfern method. Most of the prepared complexes showed high bactericidal activity and some of the complexes show more activity compared with the ligand and standards.
Anti-Bacterial Agents↗
Interaction of chloride with yeast aminopeptidase I. Equilibrium binding studies.
The effect of chloride on metal binding by yeast aminopeptidase I, as well as the binding of chloride to various enzyme forms were studied by means of a micro-centrifugation technique using radioactive 36Cl- as a ligand. Chloride did not significantly alter the binding of activating Zn2+, or binding of Co2+ to the essential metal sites. Both the native Zn2+ enzyme and Co2+-substituted aminopeptidase I bind stoichiometric amounts of C1- (1 Cl-/subunit) with apparent dissociation constants of 0.1-0.2 mM. Additional Cl- was bound at higher concentrations. In contrast to the metal-containing enzyme forms the apoenzyme did not express the high-affinity chloride binding site.
Aminopeptidases↗
Determination of cytotoxicity in vivo using 111indium-labeled human tumor cells.
Loss of radioactivity from nude mice was determined after inoculation of human tumor cells prelabeled with [111In]indium oxine (111InOx). Elimination of 111In was increased somewhat by treating the mice with diphtheria toxin (DT), which is toxic selectively for human cells compared to mice. Calcium disodium edetate (CaNa2EDTA), a metal chelating agent, facilitated elimination of 111In and increased the difference in the rates of loss of radioactivity from mice bearing viable compared to DT-killed cells.
Animals↗
Membrane lesions in cultured mouse neuroblastoma cells exposed to metal compounds.
Tritiated 2-deoxy-D-glucose (dGlc) was rapidly taken up into cultured mouse neuroblastoma C1300 cells (clone 41A3). Upon perfusion the preloaded cultures slowly released radioactivity as [3H] 2-deoxy-D-glucose-6-phosphate ([3H]dGlc-6-P) (rate const. = 0.017 min-1) from a pool corresponding to 74% (t1/2 = 41 min) of the total radioactivity incorporated. Destruction of the plasma membrane of the cells by means of Triton X-100 (1.0%) resulted in a rapid and total release of the radioactivity. CH3HgCl, HgCl2, (C2H5)3SnCl and K2Cr2O7 all caused an increase in the passive cell membrane permeability to [3H]dGlc-6-P. A membrane toxic concentration (MTC) was defined as the concentration of the tested metal compound giving rise to an increase in the relative efflux from 1.0 to 1.2 during 60 min perfusion. Using this MTC-value, the membrane toxicity of the compounds could be ranked in the following order: CH3HgCl (MTC = 9 x 10(-7) M) greater than HgCl2 (MTC = 6 x 10(-6) M) greater than (C2H5)3SnCl (MTC = 3 x 10(-4) M) greater than K2Cr2O7 (MTC = 7 x 10(-4) M). Since this differential toxicity is in accordance with other reports it is concluded that 2-deoxy-D-glucose (dGlc) may be used together with 41A3 cells to screen metal compounds for their membrane toxicity.
Animals↗
Application of a new surface labeling reagent, EDTA derivative, on erythrocytes and platelets.
The modes of binding of a new class of impermeant metal-chelating probe, the complex of 111In3+ to 1-(p-benzenediazonium) ethylenediamine tetraacetic acid (azo-phenyl-EDTA), to human and rabbit erythrocyte membranes and the effect of binding on the function of rabbit platelets have been studied. The metal chelate, azo-phenyl-EDTA.[111In3+] bound covalently to membrane proteins following reaction with intact erythrocytes. The amount and the pattern of labeling was assessed by sodium dodecyl sulfate (SDS)-polyacrylamide disc and slab gels for radioactivity. The pattern of labeling of intact human erythrocytes by azo-phenyl-EDTA.[111In3+], by pyridoxal phosphate-NaB3H7 and by galactose oxidase-NaB3H4 was also compared. The following results were obtained: (a) The pattern of labeling of intact human erythrocyte by azo-phenyl-EDTA.[111In3+] differed from other commonly used probes for labeling external membrane surfaces. Five polypeptides were labeled by the metal chelates. In addition to the known major proteins (protein band III, PAS-1, PAS-2 and PAS-3 of Fairbanks et al. (1972) Biochemistry 10, 2606--2617) a protein (radioactive band 4) which migrated slightly slower than PAS-3 in SDS gel was labeled heavily by the metal chelate. This protein has an apparent molecular weight of 37,500 in 8.4% acrylamide-SDS gel. About 40% of bound radioactivity was found in this protein. The diazo linkage of the metal chelate to this protein was found to be especially unstable to heat. (b) In rabbit erythrocyte membranes, the metal chelate bound to three polypeptides with apparent molecular weights of 96,000, 43,000 and 33,000 in 8.4% acrylamide gel. They are probably glycoproteins in nature. (c) The binding of the probe to platelets did not affect the platelet aggregability induced by adenosine diphoshpate. In vivo studies indicated that the labeled platelets accumulated at the plague of atherosclerotic rabbits. (d) The bifunctional analog of EDTA may permit new applications of metals with useful physical properties for studies of cell membranes.
Adenosine Diphosphate↗
Implanted depleted uranium fragments cause soft tissue sarcomas in the muscles of rats.
In this study, we determined the carcinogenicity of depleted uranium (DU) metal fragments containing 0.75% titanium in muscle tissues of rats. The results have important implications for the medical management of Gulf War veterans who were wounded with DU fragments and who retain fragments in their soft tissues. We compared the tissue reactions in rats to the carcinogenicity of a tantalum metal (Ta), as a negative foreign-body control, and to a colloidal suspension of radioactive thorium dioxide ((232)Th), Thorotrast, as a positive radioactive control. DU was surgically implanted in the thigh muscles of male Wistar rats as four squares (2.5 x 2.5 x 1.5 mm or 5.0 x 5.0 x 1.5 mm) or four pellets (2.0 x 1.0 mm diameter) per rat. Ta was similarly implanted as four squares (5.0 x 5.0 x 1.1 mm) per rat. Thorotrast was injected at two sites in the thigh muscles of each rat. Control rats had only a surgical implantation procedure. Each treatment group included 50 rats. A connective tissue capsule formed around the metal implants, but not around the Thorotrast. Radiographs demonstrated corrosion of the DU implants shortly after implantation. At later times, rarifactions in the radiographic profiles correlated with proliferative tissue responses. After lifetime observation, the incidence of soft tissue sarcomas increased significantly around the 5.0 x 5.0 mm squares of DU and the positive control, Thorotrast. A slightly increased incidence occurred in rats implanted with the 2.5 x 2.5 mm DU squares and with 5.0 x 5.0 mm squares of Ta. No tumors were seen in rats with 2.0 x 1.0 mm diameter DU pellets or in the surgical controls. These results indicate that DU fragments of sufficient size cause localized proliferative reactions and soft tissue sarcomas that can be detected with radiography in the muscles of rats.
Animals↗
Growth of Bacillus subtilis on citrate and isocitrate is supported by the Mg2+-citrate transporter CitM.
Bacillus subtilis 168 was assayed for its growth on tricarboxylic acid (TCA) cycle intermediates and related compounds as the sole carbon sources. Growth of the organism was supported by citrate, D-isocitrate, succinate, fumarate and L-malate, whereas no growth was observed in the presence of cis-aconitate,2-oxoglutarate, D-malate, oxaloacetate and tricarballylate. Growth of the organism on the tricarboxylates citrate and D-isocitrate required the presence of functional CitM, an Mg(2+)-citrate transporter, whereas its growth on succinate, fumarate and L-malate appeared to be CitM-independent. Interestingly, the naturally occurring enantiomer D-isocitrate was favoured over L-isocitrate by the organism. Like citrate, D-isocitrate was shown to be an inducer of citM expression in B. subtilis. The addition of 1 mM Mg(2+) to the growth medium improved growth of the organism on both citrate and D-isocitrate, suggesting that D-isocitrate was taken up by CitM in complex with divalent metal ions. Subsequently, the ability of CitM to transport D-isocitrate was demonstrated by competition experiments and by heterologous exchange in right-side-out membrane vesicles prepared from E. coli cells expressing citM. None of the other TCA cycle intermediates and related compounds tested were recognized by CitM. Uptake experiments using radioactive (63)Ni(2+) provided direct evidence that D-isocitrate is transported in complex with divalent metal ions.
Bacillus subtilis↗
Toxicological and cytophysiological aspects of lanthanides action.
Lanthanides, also called rare-earth elements, are an interesting group of 15 chemically active, mainly trivalent, f-electronic, silvery-white metals. In fact, lanthanides are not as rare as the name implies, except for promethium, a radioactive artificial element not found in nature. The mean concentrations of lanthanides in the earth's crust are comparable to those of life-important elements like iodine, cobalt and selenium. Many lanthanide compounds show particular magnetic, catalytic and optic properties, and that is why their technical applications are so extensive. Numerous industrial sources enable lanthanides to penetrate into the human body and therefore detailed toxicological studies of these metals are necessary. In the liver, gadolinium selectively inhibits secretion by Kupffer cells and it decreases cytochrome P450 activity in hepatocytes, thereby protecting liver cells against toxic products of xenobiotic biotransformation. Praseodymium ion (Pr3+) produces the same protective effect in liver tissue cultures. Cytophysiological effects of lanthanides appear to result from the similarity of their cationic radii to the size of Ca2+ ions. Trivalent lanthanide ions, especially La3+ and Gd3+, block different calcium channels in human and animal cells. Lanthanides can affect numerous enzymes: Dy3+ and La3+ block Ca2+-ATPase and Mg2+-ATPase, while Eu3+ and Tb3+ inhibit calcineurin. In neurons, lanthanide ions regulate the transport and release of synaptic transmitters and block some membrane receptors, e.g. GABA and glutamate receptors. It is likely that lanthanides significantly and uniquely affect biochemical pathways, thus altering physiological processes in the tissues of humans and animals.
Animals↗
[Nutritional and toxicological study of rats fed a diet containing tin (author's transl)].
A toxicological, nutritional and histological study of rats on a diet containing 0.5 g of tin (Sn Cl2) per 100 g of dry food for one month has been made. By gamma radioactivity measurements (with 113Sn used as a tracer) it is shown that this metal does not practically clear the digestive barrier. Otherwise the classical coefficients of nitrogen nutrition and the urinary parameters (volume, glucose, pH) are not influenced; but the growth of treated animals is obviously slower than control animals because of their reduced ingestion of food. Moreover after one month of treatment a marked anaemia results since the hematocrit and hemoglobin levels are perceptibly reduced. Lastly the histological investigations give evidence of notable irritation of the total gastrointestinal tract. This study, as that of many authors, raises the question of present permissible levels of tin (up to 250 ppm) in foods.
Animal Nutritional Physiological Phenomena↗
Experience with checking potentially contaminated materials released to the environment and testing of the measuring instruments used
Several systems with large area plastic scintillators were tested, which are used to avoid the undesirable and illegal transport of radioactive materials especially at border crossings, in metallurgical works and in plants processing metal scrap, were tested. Measuring equipment with germanium detectors, which is used for check of material released from the Dukovany Nuclear Power Plant, was also tested. The detection possibilities of a chamber with plastic scintillators, for the use during checking of materials released to the environment, were investigated.
Journal Article↗
Application of beryllium antibodies in risk assessment and health surveillance: two case studies.
This paper demonstrates that current standards used by the Occupational Safety and Health Administration (OSHA) to establish an area free from potential beryllium contamination may be inadequate. Using the Beryllium Antibody Assay, it was shown that workers exposed to former beryllium work areas, thought to be sanitized and to meet OSHA standards, experienced statistically significant rises in blood beryllium antibody titers. This finding raises the question of whether the equipment currently required to protect workers in beryllium-laden environments is sufficient. The project mission of decommissioning/decontaminating the former nuclear weapons plant at Rocky Flats Environmental Technology Site (RFETS), instituted in 1992, has necessitated development of new technology directed toward safe and responsible cleanup. Challenges have been posed not only by the need to dispose of radioactive and chemical waste, but also by the problem of cleaning up hazardous metals such as the element beryllium. Beryllium was used extensively in research and the manufacture of nuclear weapons components at Rocky Flats for over 40 years. Since inhalation of this element can induce chronic beryllium disease (Eisenbud and Lisson, 1983), an antibody assay was developed to screen workers for internal exposure to beryllium. Exposure is indicated by a titer of antibodies greater than two standard deviations above a normal population control (defined as the mean titer of pooled samples from 51 individuals with no known exposure to beryllium) and a p-value of < 0.05. This paper describes two new applications for the assay: risk assessment and health surveillance. Case study 1 involves a team of three workers who cleaned a beryllium plenum and whose beryllium antibody titers provided a quantitative assessment of their exposure. Case study 2 describes the use of the antibody assay to determine the probable manner in which one worker was exposed to beryllium while performing his duties as an architectural engineer.
Air Pollutants, Occupational↗
Mushrooms, tumors, and immunity: an update.
There is significant interest in the use of mushrooms and/or mushroom extracts as dietary supplements based on theories that they enhance immune function and promote health. To some extent, select mushrooms have been shown to have stimulatory action on immune responsiveness, particularly when studied in vitro. However, despite their widespread use for potential health benefits, there is a surprising paucity of epidemiologic and experimental studies that address the biologic activities of mushrooms after oral administration to animals or humans. There have been a number of studies that have addressed the ability of mushrooms to modulate mononuclear cell activation and the phenotypic expression of cytokines and their cognate receptors. There have also been a number of attempts to determine antitumor activities of mushrooms. Such studies are important because many of the components of mushrooms do potentially have significant biologic activity. All data, however, should be tempered by the possibility that there are toxic levels of metals, including arsenic, lead, cadmium, and mercury as well as the presence of radioactive contamination with 137Cs. In this review, we will present the comparative biology with respect to both immunological and antitumor activities of mushroom extracts and also highlight the need for further evidence-based research.
Administration, Oral↗