Mariano J. Gotelli

Mercury levels in newborns and infants after receipt of thimerosal-containing vaccines.

OBJECTIVES. Thimerosal is a mercurial preservative that was widely used in multidose vaccine vials in the United States and Europe until 2001 and continues to be used in many countries throughout the world. We conducted a pharmacokinetic study to assess blood levels and elimination of ethyl mercury after vaccination of infants with thimerosal-containing vaccines. METHODS. Blood, stool, and urine samples were obtained before vaccination and 12 hours to 30 days after vaccination from 216 healthy children: 72 newborns (group 1), 72 infants aged 2 months (group 2), and 72 infants aged 6 months (group 3). Total mercury levels were measured by atomic absorption. Blood mercury pharmacokinetics were calculated by pooling the data on the group and were based on a 1-compartment first-order pharmacokinetics model. RESULTS. For groups 1, 2, and 3, respectively, (1) mean ± SD weights were 3.4 ± 0.4, 5.1 ± 0.6, and 7.7 ± 1.1 kg; (2) maximal mean ± SD blood mercury levels were 5.0 ± 1.3, 3.6 ± 1.5, and 2.8 ± 0.9 ng/mL occurring at 0.5 to 1 day after vaccination; (3) maximal mean ± SD stool mercury levels were 19.1 ± 11.8, 37.0 ± 27.4, and 44.3 ± 23.9 ng/g occurring on day 5 after vaccination for all groups; and (4) urine mercury levels were mostly nondetectable. The blood mercury half-life was calculated to be 3.7 days and returned to prevaccination levels by day 30. CONCLUSIONS. The blood half-life of intramuscular ethyl mercury from thimerosal in vaccines in infants is substantially shorter than that of oral methyl mercury in adults. Increased mercury levels were detected in stools after vaccination, suggesting that the gastrointestinal tract is involved in ethyl mercury elimination. Because of the differing pharmacokinetics of ethyl and methyl mercury, exposure guidelines based on oral methyl mercury in adults may not be accurate for risk assessments in children who receive thimerosal-containing vaccines.

Mercury Levels in Premature and Low Birth Weight Newborn Infants after Receipt of Thimerosal-Containing Vaccines

OBJECTIVE We conducted a population-based pharmacokinetic study to assess blood levels and elimination of mercury after vaccination of premature infants born at > or =32 and <37 weeks of gestation and with birth weight > or =2000 but <3000 g. STUDY DESIGN Blood, stool, and urine samples were obtained before vaccination and 12 hours to 30 days after vaccination from 72 premature newborn infants. Total mercury levels were measured by atomic absorption. RESULTS The mean +/- standard deviation (SD) birth weight was 2.4 +/- 0.3 kg for the study population. Maximal mean +/- SD blood mercury level was 3.6 +/- 2.1 ng/mL, occurring at 1 day after vaccination; maximal mean +/- SD stool mercury level was 35.4 +/- 38.0 ng/g, occurring on day 5 after vaccination; and urine mercury levels were mostly nondetectable. The blood mercury half-life was calculated to be 6.3 (95% CI, 3.85 to 8.77) days, and mercury levels returned to prevaccination levels by day 30. CONCLUSIONS The blood half-life of intramuscular ethyl mercury from thimerosal in vaccines given to premature infants is substantially shorter than that of oral methyl mercury in adults. Because of the differing pharmacokinetics, exposure guidelines based on oral methyl mercury in adults may not be accurate for children who receive thimerosal-containing vaccines.

Original ArticleMercury Levels in Premature and Low Birth Weight Newborn Infants after Receipt of Thimerosal-Containing Vaccines

OBJECTIVE We conducted a population-based pharmacokinetic study to assess blood levels and elimination of mercury after vaccination of premature infants born at > or =32 and <37 weeks of gestation and with birth weight > or =2000 but <3000 g. STUDY DESIGN Blood, stool, and urine samples were obtained before vaccination and 12 hours to 30 days after vaccination from 72 premature newborn infants. Total mercury levels were measured by atomic absorption. RESULTS The mean +/- standard deviation (SD) birth weight was 2.4 +/- 0.3 kg for the study population. Maximal mean +/- SD blood mercury level was 3.6 +/- 2.1 ng/mL, occurring at 1 day after vaccination; maximal mean +/- SD stool mercury level was 35.4 +/- 38.0 ng/g, occurring on day 5 after vaccination; and urine mercury levels were mostly nondetectable. The blood mercury half-life was calculated to be 6.3 (95% CI, 3.85 to 8.77) days, and mercury levels returned to prevaccination levels by day 30. CONCLUSIONS The blood half-life of intramuscular ethyl mercury from thimerosal in vaccines given to premature infants is substantially shorter than that of oral methyl mercury in adults. Because of the differing pharmacokinetics, exposure guidelines based on oral methyl mercury in adults may not be accurate for children who receive thimerosal-containing vaccines.

New procedure to fortify fluid milk with iron: Metabolic and biochemical study in rats

Abstract A comparative study with two groups of 25 rats each was undertaken in order to study fluid milk fortified with SFE-171 (stabilized FeSO 4 by micro encapsulation with phospholipids) or FeSO 4 , both labeled with 59 Fe. After the administration of either product, its total absorption, biodistribution and incorporation of iron into hemoglobin was determined for both cases. In the first case the total absorption was (28.3 ± 6.0)%, whereas in the second it was (24.1 ± 5.8)%, the difference between both values is statistically significant with a P 4 . The highest amount (approximately 80%) was found in blood, followed by the liver with approximately 11% and bones with a proportion somewhat higher than 4%, the activity in intestine was minimal in both cases. The 59 Fe in blood was found 18 days after the administration of either product at a 100% in the red blood cells, which implies that the iron administered in the milk fortified with SFE-171 or with FeSO 4 was incorporated into hemoglobin. These results indicate with a high degree of significance that the fortification of milk with SFE-171 is a procedure which assures the effective absorption of iron and a physiological behavior of this element.

Bioavailability, absorption mechanism, and toxicity of microencapsulated iron (I) sulfate: studies in mice.

The iron compounds used for food fortification have to meet certain requisites related to their bioavailability, absorption mechanism, and toxicity, since they will be consumed by a massive population group. With these purposes, we evaluated a new product used for the iron fortification of milk and lacteous derivatives, called SFE-171TM, which is a ferrous sulfate, microencapsulated with phospholipids. The bioavailability studies were carried out using four groups of 30 female mice each. In two groups, we studied the absorption of ferrous ascorbate and ferrous sulfate, both in water as reference standards, which show absorptions of 13.1±4.9% and 13.2±4.3%, respectively. With the third group, we studied the absorption of ferrous sulfate in milk; its value, 7.9±3.2%, is significantly lower than that of the remaining groups, with ap<0.01. The studies with SFE-171TM in milk, were performed on the fourth group, with a result of 11.6±4.5%, demonstrating that its absorption does not differ significantly from that of the reference standards. The absorption mechanism was determined by means of in vivo self-displacement studies of the ferrous ion and the SFE-171TM, taking ferrous sulfate as the reference compound. For this study, 210 female mice were used, and no significant difference between the absorption mechanism of both products could be observed. Toxicity studies of the new product with regard to ferrous sulfate were carried out with two groups of 70 female mice each and two groups of 70 male mice each. The lethal dose 50% LD50 for SFE-171TM and for ferrous sulfate was 1200 and 680 mg/kg for female mice and 1230 and 670 mg/kg for male mice, respectively, demonstrating that the toxicity of the first product is substantially lower than that of the reference standard. We conclude that the iron product under study has a high bioavailability, an absorption mechanism equal to that of nonhemic iron, and lower toxicity than ferrous sulfate.

Contact dermatitis caused by dimethylfumarate in Argentina

For the first time in Argentina, we describe an outbreak of contact dermatitis. New pairs of shoes caused intense pruritus, pain, and eruption, followed by edema, blisters, and a severe negative impact on the epidermal barrier of the feet. We identify dimethylfumarate as the causal agent and suggest an analytical method for its fast identification.

Freon: Accidental ingestion and gastric perforation

Introduction. Freons generally have a low order of toxicity, but exposure to relatively high concentrations (>100 ppm) may produce adverse effects on health. Currently, intoxication reports are unintentional inhalation of CFCs. We report an unintentional ingestion of a mixture of CFCs and the results of a rat study. Case Report. A 43-year-old man was admitted to the Emergency Department with a chief complaint of acute abdominal pain that developed minutes after he ingested a clear liquid in a water glass, which contained a mixture of Freon and water. Subsequent surgical evaluation revealed perforation of the stomach and necrosis of the stomach wall. He developed a transient rise in his hepatic transaminases, which resolved spontaneously, and fully recovered from his surgery. Methods. A murine model of the injury was created to evaluate threshold concentration and effect of time on injury grade. Results. Injury grade increased with delay to histologic analysis from 8 to 24 hours after exposure to Freon. Increasing amounts of Freon also increased the lesion grade score. Conclusions. Patients ingesting Freon need to be closely evaluated for risk of gastric damage and perforation.