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.

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.

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.

Bioavailability of microencapsulated ferrous sulfate in fluid milk studies in human beings

Iron deficiency is one of the most important nutritional problems in the world. The best method to overcome this problem is the fortification of foods with highly bioavailable iron. Fluid milk is a massive consumption food with an easy access and which is generally the only food intake during the first months of life. Therefore the fortification of fluid milk with highly biovalable iron and no detectable alterations of its sensorial characteristics was studied in the present work. This procedure was made possible using a new type of ferrous sulfate, stabilized and microencapsulated with soy lecithin (SFE-171). The iron concentration of the fortified milk is 12 mg per liter. In order study the iron absorption from milk fortifield with this product, SFE-171 was labeled with59 Fe and given to 29 volunteers with a normal iron status, each of which received an iron quantily of 3 mg in 250 ml of fluid milk. The average iron absorption was (10.2+4.7) per cent. This result shows that the iron given in this physiocochemical form has the advantage of a high biovailability and it is possible that this product will be the first attempt for an adequate solution of iron deficiency.

Bioavailability of microencapsulated ferrous sulfate in fluid milk studies in human beings

Iron deficiency is one of the most important nutritional problems in the world. The best method to overcome this problem is the fortification of foods with highly bioavailable iron. Fluid milk is a massive consumption food with an easy access and which is generally the only food intake during the first months of life. Therefore the fortification of fluid milk with highly biovalable iron and no detectable alterations of its sensorial characteristics was studied in the present work. This procedure was made possible using a new type of ferrous sulfate, stabilized and microencapsulated with soy lecithin (SFE-171). The iron concentration of the fortified milk is 12 mg per liter. In order study the iron absorption from milk fortifield with this product, SFE-171 was labeled with59 Fe and given to 29 volunteers with a normal iron status, each of which received an iron quantily of 3 mg in 250 ml of fluid milk. The average iron absorption was (10.2+4.7) per cent. This result shows that the iron given in this physiocochemical form has the advantage of a high biovailability and it is possible that this product will be the first attempt for an adequate solution of iron deficiency. (AU)

Manual práctico para el control de calidad interno en el Laboratorio Toxicológico

[Introducción] El presente manual recopila y detalla en forma práctica y accesible todas las operaciones para controlar adecuadamente los equipos e instrumentos básicos con que debe contar un laboratorio para realizar análisis toxicológicos. También se detalla el criterio metodológico del trabajo que debe aplicarse a fin de obtener los resultados analíticos óptimos.