Determination of manganese in human brain samples.

A method is presented for the determination of manganese (Mn) in human tissue samples (especially brain) by graphite furnace atomic absorption spectrophometry (GFAAS). After complete digestion by a mixture of concentrated nitric acid (HNO3)/concentrated perchloric acid (HClO4) (50:50, v/v), the samples are assayed on a Perkin-Elmer 5100 PC apparatus, equipped with transversal graphite tubes and a Mn-specific hollow cathode lamp. The furnace conditions are as follows (for each step: temperature (degree C)/ramp (s)/duration (s)) dry 120/1/40; char 1200/5/10; atomization 2250/0/4; pyrolysis 2400/1/1. Zeeman correction is employed. The method is linear over the range 0.05 to 5.00 micrograms/g wet tissue, and the limit of detection for Mn is about 0.01 microgram/g wet tissue. This simple and rapid method may be of value for the post-mortem assessment of Mn accumulation in brain structures due to occupational or iatrogenic exposure. An application is presented in which elevated levels of Mn were determined in the brain samples of a 63-year-old female deceased after long-term total parenteral nutrition involving Mn supplementation.

Assessment of the developmental toxicity of deferoxamine in mice.

Deferoxamine (DFO), an efficient chelating agent available for the treatment of iron and aluminium overload, was evaluated for developmental toxicity in Swiss mice. Intraperitoneal injections of DFO were given to pregnant animals at 0, 44, 88, 176, and 352 mg/kg per day on gestational days 6 through 15. Maternal clinical status was monitored daily during and after treatment. Fetal parameters, including external, visceral, and skeletal malformations and variations, were assessed. Mice were killed on day 18. No maternal mortality was observed, but dams exhibited reduced body weight gain during treatment at 88, 176, and 352 mg/kg per day. Body weight at termination, corrected body weight, and food consumption were reduced in all groups. In contrast, the only significant treatment-related embryo/fetal effect was a decrease in the number of live fetuses per litter at 352 mg/kg per day. The no-observable-adverse-effect level (NOAEL) for maternal toxicity of DFO was < 44 mg/kg per day, whereas the NOAEL for developmental toxicity was 176 mg/kg per day. In summary, intraperitoneal administration of DFO to mice during organogenesis produced developmental toxicity in the presence of maternal toxicity. Because of the remarkable maternal toxicity of DFO, extreme caution in the use of this drug is recommended during pregnancy.

Mercury concentrations in marine species from the coastal area of Tarragona Province, Spain. Dietary intake of mercury through fish and seafood consumption.

A total of 592 samples of 21 species of fish, cephalopods, crustaceans and molluscs were analyzed for mercury concentrations between November 1992 and February 1993 at four sites on the Tarragona coast in Catalonia, Spain. The results of this study show that mercury discharges into the marine environment of Tarragona Province have increased the mercury content of marine organisms, with fish and crustaceans being the groups which accumulated the highest levels of this element. In a subsequent study, the individual dietary intake of mercury from fish and seafood consumption by the population of Tarragona Province was estimated to be 16 micrograms day-1. This intake of mercury would not signify a health hazard for consumers of fish and seafood from the Tarragona coastal waters.

Housing of pregnant rats in metabolism cages: maternal and developmental effects.

The influence of the caging conditions on maternal and gestational variables was assessed for pregnant rats housed individually in two cage types. Plug-positive Sprague-Dawley females were caged either in Makrolon or in metabolism (Tecniplast) cages, and were not disturbed throughout all the gestational period. Cesarean sections were performed on gestation day 20. All live fetuses were examined for external, internal, and skeletal malformations and variations. Pregnant rats were affected by the housing system, as evidenced by a significant weight loss and reduced food consumption in the animals housed in metabolism cages. A moderate increase in the number of total skeletal defects was also observed in the fetuses of dams housed in metabolism cages. An important implication of these results would be that in maternal and developmental toxicity studies of xenobiotics, pregnant animals should not be housed in metabolism cages.

Developmental toxicity evaluation of monoisoamyl meso-2,3-dimercaptosuccinate in mice.

Monoisoamyl meso-2,3-dimercaptosuccinate (Mi-ADMS), a new dimercaptosuccinic acid (DMSA) analog with enhanced lipophilic properties, was evaluated for potential developmental toxicity. Intraperitoneal injections of Mi-ADMS were given to female Swiss mice (0, 47.5, 95, and 190 mg/kg) on gestational d 6-15. The maternal clinical status was monitored daily during treatment. At termination (gestational d 18), dams were evaluated for clinical status and gestational outcome. Each live fetus was weighed and examined for external, visceral, and skeletal abnormalities. Although no maternal mortality was observed, treatment with 95 and 190 mg/kg resulted in maternal toxicity, manifested as reduced body weight gain during treatment and increased relative liver weight. Embryo/fetal toxicity, consisting of a significant increase in the number of late resorptions as well as in the percentage of postimplantation loss, reduced (nonsignificant) fetal body weight, and an increase in the incidence of skeletal defects, was also observed at 190 mg/kg/d. However, no treatment-related external or soft-tissue malformations or developmental variations were found in any group. The no-observed-adverse-effect level (NOAEL) for maternal toxicity was 47.5 mg/kg/d, whereas the NOAEL for developmental toxicity was 95 mg/kg/d. These results indicate that Mi-ADMS did not produce developmental toxicity in mice in the absence of maternal toxicity.

Effects of chronic lead and cadmium exposure on blood pressure in occupationally exposed workers.

An epidemiological study was performed to assess whether the occupational exposure to lead or cadmium is associated with an increase in blood pressure. Blood lead levels were determined in 36 male subjects who were occupationally exposed to lead, whereas urinary cadmium concentrations were determined in 40 male workers who were employed in cadmium pigment and resin factories from Barcelona (Spain). Blood lead and urine cadmium concentrations were also determined in 40 health volunteers who were not occupationally exposed to lead or cadmium (control group). The mean concentrations of blood lead were 9.8 micrograms/dL for controls and 39.5 micro/dL for lead-exposed workers, whereas 0.79 micrograms/g creatinine and 2.50 micrograms/g creatinine were the mean levels of urine cadmium for controls and for cadmium-exposed workers, respectively. After adjusting for age, body mass index, and drinking and smoking habits, a significant rise of blood pressure with the increases in blood lead levels was found in the group of lead-exposed workers, but not in the control group. In contrast, the results of this study did not corroborate the hypothesis that an increase in cadmium exposure implies a rise in blood pressure.

Lack of relationship between hair lead levels and some usual markers (blood lead levels, ZPP, urinary ALA-D) in occupationally exposed workers.

Blood and hair samples collected from 54 male workers occupationally exposed to lead were assayed for this metal by graphite furnace atomic absorption spectrophotometry. Blood ZPP and urinary ALA-D were also determined for most subjects tested. Blood and hair lead concentrations (PbB and PbH) ranged from 100 to 770 ng/ml (10 to 77 micrograms/100 ml) (mean +/- SD: 384.6 +/- 143.4 ng/ml (38.46 +/- 14.34 micrograms/100 ml)), and from 3 to 243 ng/mg (mean +/- SD: 102.4 +/- 72.6 ng/mg), respectively. No correlation was observed between the PbH and PbB values, nor between PbH and ZPP or ALA-D values. Neither hair coloration nor subjects' age were related to PbH levels. Results are discussed in the light of the existing literature.

Prevention by Tiron (sodium 4,5-dihydroxybenzene-1,3-disulfonate) of vanadate-induced developmental toxicity in mice.

Vanadate is embryotoxic and fetotoxic in golden hamsters, mice and rats. Tiron (sodium 4,5-dihydroxybenzene-1,3-disulfonate), a chelating agent widely used in analytical chemistry, is an effective antidote in the treatment of oral or parenteral vanadate poisoning. The present study evaluated the effect of administration of Tiron on sodium metavanadate (NaVO3)-induced developmental toxicity in mice. NaVO3 (25 mg/kg, i.p.) was injected on day 12 of gestation, whereas Tiron was injected subcutaneously at 0, 24, 48, and 72 hr after NaVO3 administration. Tiron effectiveness was assessed at dosage levels of 0, 250, 500, and 1,000 mg/kg. Cesarean sections were performed on gestation day 18. All live fetuses were examined for external, internal, and skeletal malformations and variations. Amelioration by Tiron of NaVO3 developmental toxicity was evidenced by a significant decrease in the number of resorbed fetuses, an increase in the mean fetal weight, and a reduction in the incidence of the skeletal variations caused by NaVO3. According to these results, Tiron offers encouragement with regard to its therapeutic potential for pregnant women exposed to vanadate. However, further investigations, including the effect of increasing the time interval between acute vanadate exposure and initiation of Tiron therapy, are required.

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.

Embryotoxicity and teratogenicity of uranium in mice following subcutaneous administration of uranyl acetate.

The effects of multiple maternal subcutaneous injections of uranyl acetate dihydrate (0.5, 1, and 2 mg/kg/d) from d 6 to d 15 of gestation were evaluated in Swiss mice. External, internal soft-tissue and skeletal examinations of fetuses were performed on gestation d 18. Maternal toxicity occurred in all uranium-treated groups as evidenced primarily by deaths as well as significant decreases in weight gain and in body weight at termination. Although it was not dose-related, embryotoxicity also occurred in all uranium-treated groups (significant increases in the number of nonviable implantations and in the percentage of postimplantation loss). Fetal body weight was significantly decreased at 1 and 2 mg/kg/d, whereas the number of total internal and total skeletal defects showed dose-dependent increases at 0.5, 1, and 2 mg/kg/d. Most morphological defects were developmental variations, whereas malformations were only detected at 1 and 2 mg/kg/d. On the basis of these data, both the maternal no-observable-adverse-effect level (NOAEL) and the NOAEL for embryotoxicity of uranyl acetate dihydrate were below 0.5 mg/kg/d, whereas the NOAEL for teratogenicity was 0.5 mg/kg/d.

Variability in the embryotoxicity and fetotoxicity of vanadate with the day of exposure.

The aim of this study was to assess the variability in the developmental toxicity of vanadate with the day of administration during gestation. Single ip injections of 25 mg sodium metavanadata/kg were given to albino Swiss mice on one of the days 9-12 of gestation. Dams were killed on day 18 of pregnancy, and fetuses were examined for external, internal and skeletal malformations and variations. The number of dead or resorbed fetuses/litter, as well as the percentage of postimplantation loss, were significantly increased with injections on days 9-12 of gestation. However, the most sensitive time for the induction of metavanadate embryotoxicity was gestational day 12. Metavanadate treatment on day 12, but not days 9-11, resulted in a significant decrease in the fetal body weight/litter. There were no external, internal or skeletal malformations, whereas the most common skeletal variations were a reduced ossification in the parietal bone, metatarsals and metacarpals, bipartite sternebrae and fused ribs. The highest percentage of total skeletal defects was found on day 12 (82.3%). Gestational day 12 is the most sensitive time for metavanadate-induced developmental toxicity in mice.

Amelioration by BAL (2,3-dimercapto-1-propanol) and DMPS (sodium 2,3-dimercapto-1-propanesulfonic acid) of arsenite developmental toxicity in mice.

Inorganic arsenic is embryotoxic and teratogenic in chicks, golden hamsters, mice, and rats. Certain dithiol chelators have been reported to protect against arsenite-induced lethality and to decrease arsenic body burden. The present study evaluated the influence of BAL (2,3-dimercapto-1-propanol) and DMPS (sodium 2,3-dimercapto-1-propanesulfonic acid), a water-soluble analogue of BAL, on arsenic-induced embryotoxic and teratogenic effects in the mouse. A series of four BAL or DMPS injections was administered sc to pregnant mice immediately after a single ip injection of 12 mg/kg of sodium arsenite given on Day 9 of gestation and at 24, 48, and 72 hr thereafter. Controls received sc corn oil with or without arsenite. Amelioration by BAL and DMPS of arsenite developmental toxicity was assessed at 15, 30, and 60 mg/kg/day, and 75, 150, and 300 mg/kg/day, respectively. BAL given following arsenite was not able to ameliorate the developmentally toxic effects of arsenite seen in mice, whereas treatment with DMPS at 150 and 300 mg/kg showed significant protective effects against arsenite embryotoxicity and teratogenicity. DMPS administration at 300 mg/kg also protected the dams against arsenite-induced maternal toxicity.

meso-2,3-Dimercaptosuccinic acid and prevention of arsenite embryotoxicity and teratogenicity in the mouse.

meso-2,3-Dimercaptosuccinic acid (DMSA), an antidote for the treatment of experimental and human poisoning by a number of heavy metals, has been reported to reduce the lethality of animals poisoned with arsenic more effectively than 2,3-dimercaptopropanol. In the present study, the effect of DMSA on arsenite-induced embryotoxic and teratogenic effects was evaluated in mice. In a first experiment, a series of four DMSA injections was administered sc to pregnant Swiss mice immediately after a single ip injection of 12 mg/kg of sodium arsenite (NaAsO2) given on Day 10 of gestation, and at 24, 48, and 72 hr thereafter. DMSA effectiveness was assessed at dosage levels of 0, 80, 160, and 320 mg/kg/day. Treatment with DMSA significantly reduced the embryolethality and the incidence of gross external and skeletal malformations and variations provoked by NaAsO2. Based on these findings, the effect of increasing the time interval between acute arsenite exposure and initiation of DMSA therapy was investigated in a second experiment. On Day 10 of gestation, DMSA (320 mg/kg) was administered sc to pregnant mice at 0, 0.25, 0.50, 1, 4, or 12 hr after a 12-mg/kg ip dose of NaAsO2. Embryotoxicity and teratogenicity derived from NaAsO2 exposure were significantly reduced when DMSA was given during the first hour after NaAsO2 injection. According to these results, a delay between acute arsenite intoxication and DMSA treatment should be avoided to have a practical beneficial effect on the arsenite exposed conceptus.

Cadmium in hair of school children living in Tarragona Province, Spain. Relationship to age, sex, and environmental factors.

Cadmium concentrations were determined in the hair of 226 school children in an industrial and in a rural area of Tarragona Province (NE Spain). The influence of sex, age, hair color, smoking habits of the household members, and parents' occupation on the children's hair cadmium levels was also evaluated. Children living in the industrial area had much more cadmium in their hair than those living in the rural area (median: 0.327 vs 0.002; arithmetic mean: 0.401 vs 0.119 micrograms/g). Girls had more cadmium in their hair than boys, and cadmium levels decreased with the age independently of the sex. Smoking habits and parents' occupation also influenced the hair cadmium content in the children examined. In contrast, hair color has no influence on hair cadmium values.

Evaluation of the maternal and developmental toxicity of aluminum from high doses of aluminum hydroxide in rats.

The potential of aluminum hydroxide [Al (OH)3] to induce developmental toxicity in rats was evaluated in the present study. Al (OH)3 was given by gavage at dose levels of 192, 384, and 768 mg/kg/day to groups of pregnant rats from day 6 through day 15 of gestation. Control animals received distilled water. Pregnant rats were evaluated for body weight, weight gain, food consumption, appearance, behavior and reproduction data. Cesarean sections were performed on gestation day 20, and the fetuses were removed for teratological evaluation. No significant maternal or developmental toxicity was observed at any Al (OH)3 dose level. Consequently, the no-observed-effect level (NOEL) for Al(OH)3 maternal or developmental toxicity would be greater than or equal to 768 mg/kg/day, which was the highest dose tested. This dose would be equivalent to a 60 kg person ingesting 16 g Al/day.

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.

Concentrations of lead and cadmium in edible vegetables from Tarragona Province, Spain.

The lead and cadmium content of 20 species of edible vegetable collected in Tarragona Province (Spain) was investigated. Samples consisting of bulbs, and leaves and soft stalks (chard, parsley, spinach and lettuce) contained the highest levels of both metals. In contrast, fruits and similar garden produce (tomato, green pepper, cucumber, artichoke, green bean and broad bean) contained the lowest concentrations of lead and cadmium in both the northern and southern area of the province. Most species analyzed did not show any significant differences between the two study areas. The mean daily intakes of lead and cadmium by man have been estimated to be: 47.5 micrograms Pb and 15.3 micrograms Cd (north), and 37.5 micrograms Pb and 32.5 micrograms Cd (south). These values do not pose a health risk for consumers, according to the levels proposed by FAO/WHO.