Browsing by Author "Luis, Henrique S."
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- Biomarkers of kidney integrity in children and adolescents with dental amalgam mercury exposure: findings from the casa pia children’s amalgam trial.Publication . Woods, James S.; Martin, Michael D.; Leroux, Brian G.; DeRouen, Timothy A.; Bernardo, Mario F.; Luis, Henrique S.; Leitão, Jorge G.; Kushleika, John V.; Rue, Tessa C.; Korpak, Anna M.Mercury is toxic to the kidney, and dental amalgam is a source of mercury exposure. Few studies have evaluated the effects of dental amalgam on kidney function in a longitudinal context in children. Here, we evaluated urinary concentrations of glutathione S-transferases (GSTs) α and π as biomarkers of renal proximal and distal tubular integrity, respectively, and albumin as a biomarker of glomerular integrity in children and adolescents 8-18 years of age over a 7 year course of dental amalgam treatment. Five hundred seven children, 8-12 years of age at baseline, participated in a clinical trial to evaluate the neurobehavioral and renal effects of dental amalgam in children. Subjects were randomized to either dental amalgam or resin composite treatments. Urinary GSTs α and π, albumin and creatinine concentrations were measured at baseline and annually on all subjects. Results were evaluated using linear regression analysis. GST-α concentrations were similar between treatment groups and in each sex and race (white vs nonwhite) group in each follow-up year. GST-π levels tended upward over the course of follow-up by 4- to 6-fold. This increase was seen in all groups irrespective of treatment, race or gender. Females had GST-π levels approximately twice those of males at all ages. Albumin concentrations were constant throughout the follow-up period and did not differ by treatment, although females had 39% higher albumin levels than males. Additionally, we found no significant effects of amalgam treatment on the proportion of children with microalbuminuria (>30 mg/g creatinine). These findings are relevant within the context of children’s health risk assessment as relates to the safety of mercury exposure from dental amalgam on kidney function. These data also provide normative values for sensitive indices of renal functional integrity that may serve in the evaluation of children and adolescents with renal disorders.
- Urinary porphyrin excretion in normal children and adolescentesPublication . Woods, James S.; Martin, Michael D.; Leroux, Brian G.; DeRouen, Timothy A.; Bernardo, Mario F.; Luis, Henrique S.; Leitão, Jorge G.; Simmonds, P. Lynne; Rue, Tessa C.Background—Urinary porphyrins are diagnostic of various metabolic disorders and xenobiotic exposures, but comprehensive normative data for urinary porphyrin concentrations in children are currently unavailable. Methods—Subjects were participants in a prospective, randomized, controlled clinical trial of dental materials safety, 8 to 12 y at inception, who were followed longitudinally for 7 y after baseline with an extensive battery of neurobehavioral, neurological, renal function and urinary porphyrin assessments. Porphyrins were quantified by HPLC. Linear regression analyses were used to measure associations of porphyrin levels with age and gender. Results—Mean concentrations, 95% confidence intervals, and 10th 50th, and 90th percentiles for all 5 typically excreted urinary porphyrins are presented by year of age and by gender. Unadjusted urinary concentrations (μg/l) of all 5 porphyrins remained relatively constant throughout the age range of 8–18 y for both males and females. In contrast, creatinine-adjusted urinary porphyrin concentrations (μg/g) declined significantly throughout this age range in both genders. Boys had significantly higher pentacarboxyl- and copro- porphyrin levels compared with girls both before and after creatinine adjustment. Conclusions—Normative longitudinal data provided herein may facilitate the clinical assessment of pediatric metabolic disorders and may be of particular relevance in evaluating porphyrin changes as a biological indicator of disease or xenobiotic exposures among children and adolescents.