Effect of ethylenediaminetetraacetic acid (EDTA) on acute mercury poisoning of toad

Studies have been carried out on the ability of EDTA (CaNa2-ethylenediaminetetraacetate) to offset the acute toxicity of mercuric chloride. The lethality of mercury was tested in female Bufo regularis species (Amphibia) which were given EDTA immediately after the Hg2+ injection. The results show that the inherent toxicity of the EDTA-mercury complex is sufficiently high for it to be ineffective as an antidote.     

Toxicity of cadmium to bacteria

Summary The toxic levels of cadmium forPseudomonas aeruginosa and a species ofAeromonas were shown to be 700–750 ppm and 225 ppm respectively. These levels are much higher than those reported in other studies. Adaptation and growth at high levels occurred only after several weeks of incubation.     

The use of the chelating agent EDTA in the treatment of acute cadmium toxicity, tissue distribution and some blood parameters in the Egyptian toad Bufo regularis

Erythrocyte count, haemoglobin content, haematocrit value, erythrocyte sedimentation rate and cadmium accumulation in some organs and tissues were estimated in toads administered 6.2 mg Cd2+/kg i.m. for 4 days. EDTA therapy caused considerable decrease in all the blood parameters studied. A striking reduction in the cadmium content of all the organs and tissues studied except the kidneys was also observed after simultaneous treatment with EDTA.     

Toxicity of cadmium to Helisoma anceps and its effect on kidney ultrastructure

When specimens of Helisoma anceps were exposed to water containing 0.1, 1, and 5 ppm cadmium, mortality was proportional to concentration but tissue levels of Cd were not. The shell was the site of highest concentration and total amount of Cd due to adsorption and active accumulation. Concentrations of Cd in the kidney and mantle were equal to or greater than the remaining soft tissue. Ultrastructural changes in the kidney associated with Cd exposure were almost exclusively confined to the nephrocytes. Graded transformation of the residual body to a secondary lysosome was proportional to the Cd concentration of the medium and length of exposure. Atypical nucleoli and reticular bodies appeared in the 1-ppm Cd dose. Only after autolysis of the nephrocytes in 5 ppm did ultrastructural changes occur in the ureter cells. Ultrastructural changes in the kidney epithelia were proportional to Cd dosage but were not necessarily indicative of the tissue burden of Cd.     

氯离子和乙二胺四乙酸对镉的植物有效性的影响

通过水培试验,向营养液中添加不同浓度的Cl^-或乙二胺四乙酸（EDTA）,研究了离子的配合作用对水稻及油菜吸收镉的影响.结果表明,随着营养液中Cl^-或EDTA浓度的增加,水稻和油菜地上部与根中镉的浓度降低.Cl^-浓度的增加抑制了水稻对镉的吸收,地上部与根部的镉含量分别从212.2和345.1 mg·kg^-1降低到34.1和209.1 mg·kg^-1.EDTA的添加抑制了水稻及油菜对镉的吸收,水稻地上部与根部的镉含量分别从212.2和345.2 mg·kg^-1降低到50.0和4.2 mg·kg^-1;油菜地上部与根部的镉含量分别从86.7和149.2 mg·kg^-1降低到22.2和12.3 mg·kg^-1.在营养液培养条件下,Cl^-或EDTA与镉的配合作用降低了植物对镉的吸收,与Cl^-相比,EDTA的抑制作用更明显.     

The isolation of metallothionein and its protective role in cadmium poisoning

People that have been subjected to cadmium poisoning show marked calcified tissue and kidney disturbances. In rats fed a cadmium-containing, low-calcium-vitamin D-deficient diet, the major portion of the cadmium accumulated in the liver and kidneys. Despite the fact that only a small amount (2.8 ppm) of cadmium completely inhibits the in vitro enzymic 1-hydroxylation reaction of 25-hydroxycholecalciferol, the in vivo 1-hydroxylation proceeded without appreciable inhibition even in the rats loaded with large amounts of oral cadmium. No light-microscopic morphological changes could be found in the kidneys of cadmium-fed rats. Most of the cadmium that accumulated in the kidneys was in a form bound to the protein, metallothionein, and therefore was not toxic to that organ. On the other hand, only 20% of the cadmium present in bone appears to be protein bound. The data strongly suggest that the protective effect of metallothionein in the kidney is serendipitous when involved in cadmium poisoning and that cadmium ion acts directly on bone rather than by an indirect action through a functional disturbance of the kidney.     

Metallothioneins and resistance to cadmium poisoning in Drosophila cells

Toxicity of cadmium on Drosophila cell lines has been studied. Maximal tolerance for cadmium chloride is 10 microM. Metallothioneins are induced in Drosophila cells following cadmium addition. A stable cadmium resistant cell line (Cd R200) has been selected starting from the haploid D clone. The Cd R200 cells are diploid and display metallothionein levels 22 times higher than cells of the original line fully induced with cadmium. The 200 microM CdCl2 tolerance upper limit in Cd R200 line is overcome if L-cysteine is supplemented to the medium. It is thus possible, in the presence of 5 mM L-cysteine, to select cells able to resist 800 microM CdCl2. These cells produce 4 times more metallothioneins than Cd R200 cells.     

Absorption of cadmium after a long-term oral administration of cadmium to dogs

A long-term experiment using beagle dogs to investigate the absorption of cadmium was conducted. The dogs in the experimental groups were given a commercial diet and pelleted food containing 1, 3, 10, 50, and 100 mg of cadmium per day. The cadmium concentration in the blood increased continuously, gradually reaching a steady state following the administration of cadmium. The cadmium excreted daily in urine increased continuously. The cumulative excreted amount of cadmium in urine was calculated by using the trapezoidal rule based on the data of excretion of cadmium in urine. Then the absorbed fraction of administered cadmium was estimated on the basis of the relationship between the cumulative excreted amount of cadmium in urine and the cumulative administered dose of cadmium after the cadmium concentration in blood reached a steady state. The absorbed fraction of cadmium decreased with an increase in the administered dose of cadmium. A dose-dependent increase between the absorbed amount and the administered dose was observed.     

Assessment of Cu-Zn EDTA Parenteral Toxicity in Calves

Copper (Cu) parenteral administration is used in a beef cow-calf operations to prevent or correct Cu deficiency in bovines. At present, Zinc (Zn) salts have been incorporated to complement Cu antioxidant effect. A risk of hepatotoxicity generated by overdose is a negative consequence of injectable Cu application. Cu-Zn EDTA appears as an alternative; however, data about its toxicity is unknown. The aim of this study was to assess toxicity risk of different doses of Cu-Zn EDTA in calves. Thirty two Aberdeen Angus calves of 162 (±20) kg BW were assigned to 4 groups (n = 8), homogeneous in weight, sex, and age. Cu-Zn EDTA was administrated in doses of 0.3 mg/kg BW (group 1X); 0.6 mg/kg BW (group 2X); 0.9 mg/kg BW (group 3X) and sterile saline solution (control group-with no treatment). Clinical and blood parameters in animals were monitored during 28 days. In groups’ control, 1X and 2X there were no alterations in the assessed parameters. In group 3X, one of the animals showed depression, permanent decubitus, and muscular twitching; that animal had to be killed in extremis for humanitarian reasons. Necropsy and Cu tissue concentration findings confirmed intoxication in the clinically affected animal. The rest of the animals in group 3X showed only a temporary increase in liver enzymes. The results indicate that a dose of 0.9 mg/kg BW of Cu as Cu-Zn EDTA is potentially hepatotoxic, this dose is similar to other soluble salts of parenteral administration.     

Toxicity of cadmium chloride and lead nitrate to Chironomus tentans larvae

Chironomid larvae form an important link in aquatic food chains. Effluents from textile and pulp mills contain cadmium and lead salts which are dangerous to chironomid larvae, an important fish food. Toxicities of cadmium chloride and lead nitrate were studied under experimental conditions and the mean survival time and LD₁₀₀ values were calculated.Results suggest that following poisoning by CdCl₂ the total protein contents of the chironomid larvae decrease. This may diminish the nutritive value of these larvae as fish food. Qualitative analysis of larvae following exposure to CdCl₂ and Pb(NO₃)₂ showed that these heavy metals were taken up by the chironomids.     

Studies of Zn, Mg, Cu, Ca and Fe in cadmium poisoned toads before and after treatment with EDTA

Zn, Mg, Cu, Ca and Fe were determined spectrophotometrically in liver, kidneys, muscle, spleen and blood of Bufo regularis after a single i.m. injection of 6.2 mg Cd/kg (which represents the 96 hr LD50) alone or in combination with 40 mg EDTA/kg (the minimal EDTA concentration causing 100% survival over that period). Cadmium administration caused recognizable effects on the essential metals levels in different tissues and organs. In the majority of the tissues and organs studied, zinc and copper concentrations returned to their normal ranges in animals that received both cadmium and EDTA. In contrast, magnesium, calcium and iron contents not only returned back to their control values but also exceeded them.