Health risks of dietary intake of environmental pollutants by elite sportsmen and sportswomen.

The dietary intake of arsenic (As), cadmium (Cd), mercury (Hg), lead (Pb), hexachlorobenzene (HCB), polychlorinated naphthalenes (PCNs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated diphenyl ethers (PCDEs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) by elite sportsmen and sportswomen of Catalonia, Spain, was assessed. In 2000, food samples were randomly acquired in various cities of Catalonia. Analysis of the above pollutants were determined according to the appropriate analytical techniques (ICP-MS, HRGC/HRMS, HPLC). In general terms, elite sportsmen and sportswomen showed a higher intake of Cd, Hg, Pb, HCB, PCNs, PCDD/Fs and PAHs than the general population, while it was lower for PCDEs (both sexes), and PCBs and PBDEs (women). According to the FAO/WHO provisional tolerable weekly intake (PTWI) for metals, the WHO tolerable daily intake (TDI) for HCB, and the US EPA's reference dose (RfD) for PAHs, the dietary intakes of environmental pollutants should not mean a potential toxic hazard. However, the WHO-TDI for PCDD/Fs and "dioxin-like" PCBs is exceeded in sportsmen. The current results indicate that the consumption of those food groups showing the highest contribution to the intake of these pollutants should be diminished. In relation to this, the reduction of the consumption of dairy products and cereals would be important.

Chelating agents in the treatment of acute vanadyl sulphate intoxication in mice.

Eighteen chelating or reducing agents were tested to determine their relative efficacy as antagonists in acute intramuscular vanadyl sulphate intoxication in mice. The chelating or reducing agents were administered intraperitoneally to male Swiss mice at doses equal to one-fourth of their respective LD50. Therapeutic effectiveness (TEF) was calculated. In a subsequent experiment, the effect of EDTA, glutathione, DFOA, ascorbic acid, succinic acid, monosodium phosphate, Tiron, DTPA, and 2-mercaptosuccinic acid on the excretion, and distribution of vanadium was determined. Of the compounds examined, Tiron followed by ascorbic acid, and 2-mercaptosuccinic acid were effective in increasing the urinary excretion of vanadium. Tiron, and 2-mercaptosuccinic acid were also effective in reducing the concentration of vanadium found in kidney, the main target organ of vanadium accumulation. Tiron appears to be the most effective agent of those tested in the prevention of acute vanadium (IV) intoxication in mice.

Effectiveness of sodium 4,5-dihydroxybenzene-1,3-disulfonate (Tiron) in protecting against uranium-induced developmental toxicity in mice.

The effect of Tiron (sodium 4,5-dihydroxybenzene-1,3-disulfonate), a chelating agent used in the treatment of experimental poisoning by a number of heavy metals, on uranium-induced developmental toxicity was evaluated in Swiss mice. A series of four Tiron injections was administered intraperitoneally to pregnant mice immediately after a single subcutaneous injection of 4 mg/kg of uranyl acetate dihydrate given on day 10 of gestation and at 24, 48, and 72 h thereafter. Controls received 0.9% saline with or without uranyl acetate. Tiron effectiveness was assessed at 500, 1000 and 1500 mg/kg per day. Amelioration by Tiron of uranium-induced embryolethality was not noted at the two lower doses. The percentage of dead and resorbed fetuses in the Tiron-treated groups was not statistically different from that in the positive control group. However, treatment at 1500 mg/kg per day showed isolated protective effects against uranium fetotoxicity, such as that evidenced by the lack of differences in fetal body weight between this group and the uranium-untreated group, as well as by a decrease in the number of skeletal defects. According to these results, the ability of Tiron to protect the developing mouse fetus against uranium-induced developmental toxicity offers only modest encouragement with regard to its possible therapeutic potential for pregnant women exposed to this metal.

The developmental toxicity of uranium in mice.

To evaluate the developmental toxicity of uranium, 5 groups of 20 pregnant Swiss mice were given by gavage daily doses of 0, 5, 10, 25 and 50 mg/kg of uranyl acetate dihydrate on gestational days 6-15. Cesarean sections were performed on all females on gestation day 18. Fetuses were examined for external, visceral, and skeletal abnormalities. The results indicated that such exposure resulted in maternal toxicity as evidenced by reduced weight gain and food consumption during treatment, and increased relative liver weight. There were no treatment-related effects on the number of implantation sites per dam, or on the incidence of postimplantation loss (resorptions plus dead fetuses). The number of live fetuses per litter and the fetal sex ratio were not affected by the treatment. However, dose-related fetal toxicity, consisting primarily of reduced fetal body weight and body length, and an increased incidence of abnormalities was observed. Malformations (cleft palate, bipartite sternebrae) and developmental variations (reduced ossification and unossified skeletal variations) were noted at the 25 and 50 mg/kg per day test levels. Therefore, administration of uranyl acetate dihydrate during organogenesis in mice produced maternal toxicity at 5, 10, 25 and 50 mg/kg per day. The "no observable effect level" (NOEL) for fetotoxicity including teratogenicity was below 5 mg/kg per day, as some anomalies were observed at this dose. There was no evidence of embryolethality at any dosage level used in this study.

Meso-2,3-dimercaptosuccinic acid (DMSA) affects maternal and fetal copper metabolism in Swiss mice.

Meso-2,3-dimercaptosuccinic acid (DMSA) is a chelating agent used to treat heavy metal intoxication. DMSA has been reported to be teratogenic in the mouse, and it has been suggested that this teratogenicity may be secondary to DMSA-induced alterations in Zn metabolism. In the present study, 0, 400 or 800 mg DMSA/kg body weight were administered on gestation days 6-15 to pregnant Swiss mice by gavage (PO) or subcutaneous injection (SC). Mice were fed a diet containing 14 micrograms Zn, 10 micrograms Cu, 120 micrograms Fe, 1175 micrograms Mg and 6.8 mg Ca/g diet. A sub-group of mice in the 800 mg DMSA/kg SC group was fed a diet containing 250 micrograms Zn/g. DMSA administration did not result in overt maternal toxicity. There was no effect of the drug on fetal or placental weight, or on crown-rump length. However, some fetuses from DMSA-treated dams were characterized by skeletal abnormalities including supernumerary ribs, unossified anterior phalanges and malformed sternebrae. Drug exposure was not associated with consistent changes in tissue Zn, Fe, Ca or Mg levels. Supplemental Zn had no marked effects on the fetus. Fetal liver Cu concentrations exhibited dose-dependent decreases with increasing DMSA dose. This finding suggests that the developmental toxicity of DMSA may be mediated through disturbed maternal/fetal copper metabolism.

Evaluation of the developmental toxicity of 2,3-dimercapto-1-propanesulfonate (DMPS) in mice. Effect on mineral metabolism.

The sodium salt of 2,3-dimercapto-1-propanesulfonic acid (DMPS), a potent chelating agent used in the treatment of inorganic and organic heavy metal intoxications was evaluated for developmental toxicity in pregnant Swiss mice. DMPS was administered by gavage at doses of 0, 75, 150 and 300 mg/kg per day on gestational days 6-15. Females were evaluated for body weight gain, food consumption, appearance and behavior, survival rates and reproduction data. Cesarean sections were performed on gestation day 18. There were no maternal toxic effects, and no treatment-related changes were recorded in the number of total implants, resorption, the number of live and dead fetuses, fetal body weight or fetal sex distribution data. Gross external, soft tissue and skeletal examination of the DMPS-treated fetuses did not show significant differences at any dose in comparison with the controls. Mineral analysis of maternal and fetal tissues revealed slight effects of DMPS on metabolism of calcium, magnesium, zinc, copper and iron. The results of this study in mice indicate that DMPS is not a developmental toxicant at levels up to 300 mg/kg per day.

Oral vanadium administration to streptozotocin-diabetic rats has marked negative side-effects which are independent of the form of vanadium used.

In the present investigation, the effects of oral administration of sodium metavanadate, sodium orthovanadate and vanadyl sulphate to alleviate some signs of diabetes in streptozotocin-treated rats have been evaluated. Streptozotocin-induced diabetic rats drank aqueous solutions (NaCl, 80 mM) containing sodium metavanadate (0.15 mg/ml), sodium orthovanadate (0.23 mg/ml), or vanadyl sulphate pentahydrate (0.31 mg/ml) for 28 days. The vanadium-treated animals were compared to controls, either diabetic or nondiabetic, receiving drinking water containing NaCl (80 mM) only. Daily food and fluid intake were significantly decreased in the vanadium-treated animals relative to diabetic controls. Also, vanadium treatment reduced the level of hyperglycemia in diabetic rats, with sodium metavanadate being the most effective of the vanadium compounds tested. However, daily vanadium intake was significantly lower in the animals receiving sodium metavanadate. Signs of toxicity were observed in all vanadium-treated animals as evidenced by some deaths, decreased weight gain, and increased serum concentrations of urea and creatinine. Moreover, vanadium was detected in all tissues analyzed. Although some signs of diabetes were improved by vanadium treatment, because of the severe toxic side effects noted in all of the vanadium-treated animals, it seems evident that oral vanadium administration is not a suitable therapy of diabetes mellitus in streptozotocin-diabetic rats.

The effect of age on aluminum retention in rats.

The present study was designed to assess potential changes in aluminum (Al) retention during advanced age. Young (21 day old), adult (8 months), and old (16 months) rats were exposed to 0, 50, and 100 mg Al/kg/day administered as aluminum nitrate in drinking water for a period of 6.5 months. Urinary Al levels were measured after 3 and 6.5 months of Al exposure. Organ weights and tissue Al concentrations were examined at 6.5 months of Al administration. Differences in the tissue accumulation of Al with age included higher liver, kidneys, spleen, bone and testes levels in old rats than in tissues of both young or adult animals. In contrast, brain concentrations were higher in young rats. Urinary Al levels of young, adult or old Al-exposed rats showed different trends at 6.5 months of Al exposure: compared with young values adult values declined, while those of old rats tended to increase further. The current results show that tissue Al retention patterns may be significantly altered depending on the age at Al exposure. This finding may be of concern for future investigations on the potential role of Al in certain neurological disorders.

Comparative effects of the chelators sodium 4,5-dihydroxybenzene-1,3-disulfonate (Tiron) and diethylenetriaminepentaacetic acid (DTPA) on acute uranium nephrotoxicity in rats.

Sodium 4,5-dihydroxybenzene-1,3-disulfonate (Tiron) and diethylenetriaminepentaacetic acid (DTPA) are two chelating agents that have been demonstrated to be effective in the treatment of experimental poisoning by a number of heavy metals. In this study, the effects of Tiron and DTPA on uranium-induced nephrotoxicity were evaluated in a rat model. A series of four Tiron or DTPA injections was administered intraperitoneally to adult male Sprague-Dawley rats immediately after a single subcutaneous injection of uranyl acetate dihydrate (5 mg/kg) and at 24, 48 and 72 h thereafter. Positive and negative control groups received 0.9% saline with or without uranyl acetate, respectively. Tiron effectiveness was assessed at 400, 800 and 1600 mg/kg, whereas DTPA was administered at 250, 500 and 1000 mg/kg. Although the urinary excretion of uranium was significantly enhanced by Tiron administration, significant amounts of uranium still remained in the kidney at the end of the treatment. However, the partial reduction of the renal uranium concentrations was in accordance with the amelioration noted in some urinary and serum indicators of uranium nephrotoxicity. Moreover, Tiron administration also reduced the severity of the uranium-induced histological alterations in the kidney. According to these results, Tiron offers only a modest encouragement with regard to its possible therapeutic potential to treat acute uranium-induced nephrotoxic effects. In turn, DTPA was less effective than Tiron in protecting against the nephrotoxicity of uranium in rats.

Vanadium treatment of diabetic Sprague-Dawley rats results in tissue vanadium accumulation and pro-oxidant effects.

The effect of sodium metavanadate (NaVO3) consumption on trace element metabolism, components of the antioxidant defense system and lipid oxidative damage were studied in control (CON) and streptozotocin-induced diabetic (DIAB) rats. Ten days after injection, CON and DIAB rats received either 0 mM NaVO3/80 mM NaCl (0 group) or 1.2 mM NaVO3/80 mM NaCl (1.2V group) in their drinking water. DIAB groups had higher food and fluid intakes than the CON groups; vanadium (V) groups had lower food and fluid intakes than the saline groups. Vanadium therapy lowered plasma glucose concentrations of DIAB rats. The following parameters were similar among the groups: plasma Zn, Cu and Fe concentrations, plasma ceruloplasmin activity, liver Zn, Cu, Mn and Fe concentrations, kidney Mn and Fe concentrations, liver non-Se-dependent glutathione peroxidase (GSH-Px), glutathione reductase (GSH-Red) and Mn-SOD activities, liver reduced glutathione (GSH) and oxidized glutathione (GSSG) concentrations and kidney non-Se-dependent GSH-Px activity. Kidney Zn and Cu concentrations were higher in DIAB rats than in CON rats. The CON-1.2V and DIAB-1.2V groups had V accumulation in the liver and kidney. Liver CuZn-SOD and Se-dependent GSH-Px and kidney CuZn-SOD and GSH-Red activities were lower in DIAB rats compared to CON rats; kidney Mn-SOD and kidney Se-dependent GSH-Px activities were higher in DIAB rats than CON rats. Vanadium treatment did not cause significant alterations in the antioxidant defense system; however, tissue vanadium concentrations were positively correlated to TBARS production. These results show that diabetes caused significant alterations in the antioxidant defense system and that V therapy was associated with a marked deterioration in health of both control and diabetic rats.

Reproductive toxicity evaluation of vanadium in male mice.

The reproductive toxicity of vanadium was studied in mice. Male Swiss mice were exposed to sodium metavanadate at doses of 0, 20, 40, 60, and 80 mg/kg per day given in the drinking water for 64 days. To evaluate the fertility of the vanadium-treated animals, males were mated with untreated females for 4 days. A significant decrease in the pregnancy rate was observed at 60 and 80 mg/kg per day of sodium. metavanadate. However, metavanadate did not reduce fertility in male mice at 20 and 40 mg/kg per day. Reproductive toxicity was measured by sperm count, sperm motility, organ weights, and histologic evaluation of the testes. Decreased body and epididymis weight was only observed in the 80 mg/kg per day group, while testicular weights were not altered by the treatment with all doses used. Sperm count was significantly decreased at 40, 60, and 80 mg/kg per day, but the sperm motility was unaffected. Histopathological examination revealed that the testes were normal and that the epididymis of treated male mice contained normal appearing sperm. The no observed adverse effect level (NOAEL) was 40 mg/kg per day. Consequently, vanadium would not cause any adverse effect on fertility or testicular function in male mice at the concentrations usually ingested by humans through the diet and drinking water.

Effects of vanadium on reproduction, gestation, parturition and lactation in rats upon oral administration.

Sodium metavanadate was tested for its effects on fetal development, reproduction, gestation and lactation in Sprague Dawley rats. Male rats were administered NaVO3 po at doses of 0, 5, 10 and 20 mg/kg/day for sixty days before mating with females which had received the same doses from 14 days previous to mating. These females received 0, 5, 10 and 20 mg NaVO3/kg/day during the periods of gestation and lactation. No significant adverse effects could be observed on: number of corpora lutea, implantations, live and dead fetuses, and resorptions. Significant decreases were observed in the development of the pups in all the vanadium -treated groups. All the doses used produced toxic effects in the offspring.

The effects of aluminium ingestion on reproduction and postnatal survival in rats.

Aluminium nitrate was tested for its effects on reproduction, gestation, and lactation in Sprague-Dawley rats, at dosages of 0, 180, 360 and 720 mg/kg/day. Mature male rats were treated orally for 60 days prior to mating with mature virgin female rats treated for 14 days prior to mating with treatment continuing throughout mating, gestation, parturition, and weaning of the litters. One-half of the dams in each group were killed on day 13 of gestation and the remaining dams were allowed to deliver and wean their offspring. Postnatal development was monitored. No adverse effects on fertility or general reproductive parameters were evident at doses employed in these studies. However, the survival ratios were higher for the control group. Moreover, a dose-dependent delay in the growth of the living young could be observed in aluminium treated groups. Therefore, it would seem that high amounts of aluminium should not be ingested during the periods of gestation.

Tiron administration minimizes the toxicity of vanadate but not its insulin mimetic properties in diabetic rats.

Although it has been reported that vanadate is effective in diminishing the expression of diabetes in the rat, the severe toxic side effects noted in the vanadate-treated animals suggest that chronic oral administration of vanadate argues against its use in human diabetes. The present study was conducted to evaluate the effects of the chelator Tiron on the mobilization of vanadium after administration of sodium metavanadate in the drinking water (0.20 mg/ml) of streptozotocin-induced diabetic rats for 35 days. Intraperitoneal treatment with Tiron (300 or 600 mg/kg) was initiated after three weeks of vanadate administration and continued for two weeks. The ameliorative effects of vanadium with respect to diabetes were not diminished by the administration of Tiron, but the accumulation of vanadium in kidney and bone was significantly decreased in the Tiron-treated groups and diabetes associated increases in serum GOT, GPT and cholesterol were diminished with Tiron treatment. It is concluded that the coadministration of metavanadate and Tiron may be of potential value for treatment of diabetes mellitus.

Age-related effects of aluminum ingestion on brain aluminum accumulation and behavior in rats.

Both aluminum and aging have been associated with neurobehavioral changes in mammals. This study assessed in young (21 day old), adult (8 months), and old rats (16 months) the effects of prolonged aluminum ingestion on open-field activity and passive-avoidance conditioning. Aluminum was administered in drinking water as aluminum nitrate at doses of 0, 50, and 100 mg Al/kg/day over a 6.5 month period. There were no aluminum effects on the horizontal and vertical activity in an open-field, or in passive-avoidance learning in any group. On the other hand, measurement of aluminum concentrations in a number of brain regions indicated that the olfactory bulb and the rhachidical bulb were the regions with the highest aluminum levels, while the cortex and the thalamus were the cerebral regions showing the lowest aluminum content. For most brain regions analyzed the highest aluminum concentrations were found in young rats, which would indicate that early stages of the life cycle must be considered for enhanced brain aluminum accumulation.

Acute toxicity of vanadium compounds in rats and mice.

Sodium metavanadate (NaVO3) and vanadyl sulphate pentahydrate (VOSO4 X 5H2O) were administered to rats and mice. The following LD50 (14-day) were determined: NaVO3, 98.0 mg/kg (rats) and 74.6 mg/kg (mice) when given orally, and 18.4 mg/kg (rats) and 35.9 mg/kg (mice) when given i.p.; VOSO4 X 5H2O, 448.0 mg/kg (rats) and 467.2 mg/kg (mice) when given orally, and 74.1 mg/kg (rats) and 113.0 mg/kg (mice) when given i.p. The majority of deaths occurred during the first 24 h. The clinical and physical signs appearing after the intoxication include irregular respiration, diarrhea, ataxia and paralysis of the hind legs. These signs disappeared for the most part after 48 h, which suggests a quick elimination of vanadium.

Protection of mice against the lethal effects of sodium metavanadate: a quantitative comparison of a number of chelating agents.

10 Chelating agents were administered to mice by intraperitoneal (i.p.) injection in order to compare their relative effectiveness in preventing death after a single i.p. injection of NaVO3. Ascorbic acid, Tiron (4,5-dihydroxy-1,3-benzene-disulfonic acid) and deferoxamine were the most effective antidotes for acute NaVO3-toxicity. The therapeutic index of ascorbic acid against 0.61 mmol/kg NaVO3 was found to be 95.2. This was 4.6 and 12.2 times greater than those of Tiron and Deferoxamine respectively. L-Cysteine greater than Na2CaEDTA greater than Na3CaDTPA reduced the acute mortality of mice following i.p. injection of NaVO3. Sodium salicylate, D,L-penicillamine, DMSA and DDC were not effective as antidotes for acute NaVO3-toxicity.

Evaluation of the efficacy of various chelating agents on urinary excretion and tissue distribution of vanadium in rats.

The effect of repeated intraperitoneal administration of Tiron (4,5-dihydroxy-1,3-benzenedisulfonic acid), ascorbic acid, deferoxamine (DFOA) or 2-mercaptosuccinic acid on urinary excretion and tissue distribution of vanadium was assessed in rats which had previously received 12 intraperitoneal injections of sodium metavanadate (1.84 mg/kg per injection) or vanadyl sulphate trihydrate (6.35 mg/kg per injection) during a 4-week period. Chelating agents were administered daily for 5 days at doses equal to one-eighth of their respective LDSO. Only Tiron significantly decreased the tissue concentration of vanadium, whereas DFOA and Tiron significantly enhanced the urinary excretion of vanadium after repeated parenteral administration of sodium metavanadate. Again, only Tiron significantly increased the urinary elimination of vanadium following vanadyl sulphate administration. The results of this study show that Tiron has potential beneficial effects in the treatment of repeated intraperitoneal vanadium poisoning, while the effectiveness of DFOA is very uncertain. 2-Mercaptosuccinic and ascorbic acids were not effective as antidotes for parenteral vanadium intoxication.

Maternal and developmental toxicity of manganese in the mouse.

Manganese (II) chloride tetrahydrate was investigated in Swiss mice for maternal and developmental toxicity after subcutaneous (s.c.) exposure to doses of 0, 2, 4, 8 and 16 mg/kg per day from gestation day 6 through 15. Females were sacrificed on gestation day 18, and fetuses were examined for external, visceral, and skeletal abnormalities. Maternal toxicity included significant reductions in weight gain and food consumption at 8 and 16 mg/kg/day, as well as several treatment-related deaths in the high dose-group. There were no treatment-related effects on the number of total implants, early resorptions, dead fetuses or sex ratio, whereas a significant increase in the number of late resorptions was found in the 4, 8, and 16 mg/kg/day groups. Fetotoxicity, consisting primarily of reduced fetal body weight and an increased incidence of morphological defects was also observed at 8 and 16 mg/kg/day. There were no differences between control and manganese-treated groups in the incidence of individual or total malformations. The no observable adverse effect level (NOAEL) for maternal toxicity of MnCl2 x 4H(2)0 in mice was 4 mg/kg/day, while the NOAEL for embryo/fetal toxicity was 2 mg/kg/day.