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Urinary biomarkers of aflatoxin exposure in young children in Egypt and Guinea
Abstracts / Toxicology Letters 164S (2006) S1–S324
It follows from our results that the synthesis of pterin derivatives, i.e. neopterin and biopterin, is influenced by diverse stress factors. Neopterin and biopterin serum concentrations may thus provide additional information on the influence of stress factors on the porcine organism in vivo, and, at the same time, they extend the modest list of papers on pterins in veterinary practice.
S161
This project was supported by grant PO2 ES09601 from the National Institutes of Environmental Health Sciences (NIEHS), NIH and EPA R826886 from the U.S. Environmental Protection Agency. Its contents are the responsibility of the authors and do not necessarily represent the official views of the NIEHS, NIH or EPA. doi:10.1016/j.toxlet.2006.06.334
doi:10.1016/j.toxlet.2006.06.333 P10-16 Lessons learned from longitudinal studies to identify high exposure groups using OP pesticide urinary biomarkers Elaine M. Faustman, William C. Griffith, Eric Vigoren University of Washington, Washington, United States We reanalyze data on a urinary biomarker, TCP a metabolite of an organophosphate pesticide (OP) chlorpyrifos in two populations to understand issues in identifying highly exposed individuals. The studies being reanalyzed are two population-based samples, one of 79 persons from Maryland over a 12-month period and the other of 90 persons from Minnesota over a 4-day period. Both data sets have longitudinal measurements of urinary metabolites so that within and between person variances can be estimated after accounting for any major temporal trends and effects of other important covariates, such as gender and age. An important feature of the between and within person variances emerged from the analysis is that the within person variance is larger than the between person variance in both populations. The large within person variance makes it difficult to identify which individuals are most highly exposed in these populations. For example, if you try to identify individuals in the upper 10% of the population, only 20–30% would be correctly identified after a single measurement and 65–75% after 20 measurements. A similar pattern of large within person variability compared to between person variability has been observed in a study of diakyl metabolites in urine of 44 children of farmworkers in the Yakima Valley of Washington over a 21 month period. This suggests that in similarly exposed populations it will be difficult to conduct epidemiological studies of diseases associated with higher exposure because of exposure misclassification. The large within person availability also suggests that future studies should include multiple measurements on the same person so that estimates of the between person variability be made to describe the population variability in exposure. Estimates of the population variability are useful for probabilistic risk assessment of cumulative exposures.
P10-17 Urinary biomarkers of aflatoxin exposure in young children in Egypt and Guinea Nektaria Polychronaki 1 , Christopher Wild 2 , Hannu Mykk¨anen 1 , Mosaad Abdel-Wahhab 3 , Abdoulaye Sylla 4 , Mamadou Diallo 4 , Hani El-Nezami 1 , Paul Turner 2 1 University
of Kuopio, Finland; 2 University of leeds, Leeds, UK; 3 National Research centre, cairo, Egypt; 4 Institut Pasteur de Guinee, Kindia Chronic exposure to the fungal toxins aflatoxins (AFs) is considered to be a major risk factor in the development of primary liver cancer. In parts of Africa AF exposure is common and early life exposure could be a contributing factor towards the early onset of liver cancer in adulthood. This project assessed the level of exposure of children to aflatoxin in Egypt (predicted moderate aflatoxin exposure) and Guinea (predicted high aflatoxin exposure) by measurement of AF metabolites in urine. Aflatoxins were extracted from urine samples of 50 Egyptian (aged 1–1.5 years) and 50 Guinean children (aged 2–4 years) by C18 cartridges and aflatoxin immunoaffinity columns and analyzed by HPLCfluorescence. AFB1, AFB2, AFG1, AFG2 and AFM1 were detected in children’s urine and the identities of the aflatoxins were confirmed by spiking with aflatoxin standards and co-chromatography using different HPLC conditions. AF were less frequently present in Egyptian than Guinean children (38% versus 86%) with statistically significant differences in prevalence for most of the detected toxins (AFB1 (2% versus 16%, p = 0.016), AFB2 (10% versus 58%, p = 0.000), AFG1 (4% versus 2%), AFG2 (24% versus 36%, p = 0.190) and AFM1 (8% versus 64%, p = 0.000). For AFM1 the mean levels in Guinea were 18-fold higher than in Egypt. Worldwide there is a scarcity of urinary biomarker data for AF exposure in children. The lower frequencies of both AFB1 and AFG1 in the urine mostly likely reflect conversion of the dietary AF to other metabolites in the liver. Overall AF exposure in Egypt is modest in compar-
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Abstracts / Toxicology Letters 164S (2006) S1–S324
ison to Guinea though it should be noted that more of the Egyptian children in this study were still at least partially breast feeding, and thus may be protected against exposure due to the limited passage of AF into breast milk. These data would suggest that measures to reduce AF exposure in both regions are important although the situation is particularly pressing in Guinea where exposure is more prevalent and at higher levels. doi:10.1016/j.toxlet.2006.06.335 P10-18 The verification of the “drug addictive” status in drug abuse legal cases in Greece M.A. Savvopoulos 1 , M.N. Tzatzarakis 2 , M. Toutoudaki 2 , M. Christaki 2 , E. Pallis 2 , A.M. Tsatsakis 2 1 Center
of Toxicological Sciences and Research, Department of Medicine, University of Crete, Heraklion, Greece; 2 Center of Toxicological Sciences and Research, Department of Medicine, University of Crete, Heraklion, Greece The Court should decide whether the defendant is a drug addict or a simple user. The law demands an expert report (i.e. medical, psychiatric, clinical, toxicological or other, e.g. segmental hair testing) to be conducted. One hundred and twenty five legal cases related to the judicial verification of drug dependence and over than 2500 expert reports conducted by the medical examiner were studied. Information from each file about the process, the decision, the police record, the indictment, the expert reports, the defendant’s individuality, the crimes, the penal confrontal, etc. were classified into 11 groups. Conclusions on the kind of the expert report, the evident value of each kind of the expert reports, are presented. The following procedure is compared to the rightful procedure. Three legal cases and three expert reports were methodically examined and analytically presented. The expert report is not committing for the Court. The District Attorney is allowed to choose the kind of the expert report to be done. The kind of the report depends on the available technostructure and human resources. Evaluation of the nine common scientific criteria of addiction is presented. The chronic frames and the examination by several experts are impossible to be kept to. Hair testing is accepted in Court, although is not specially refereed in any Law. doi:10.1016/j.toxlet.2006.06.336
P10-19 Evaluation of methylmercury cytotoxicity at intestinal level S. Torres 1 , M.J. Laparra 2 , V. Devesa 1 , D. V´elez 1 , R. Barber´a 2 , R. Montoro 1 , R. Farre 2 1 Instituto
de Agroqu´ımica y Tecnolog´ıa de Alimentos (IATA-CSIC), Aptdo 73, 46100 Burjassot, Valencia, Spain; 2 Nutrition and Food Chemistry, Faculty of Pharmacy, University of Valencia, Avda. Vicente Andr´es Estell´es s/n, 46100 Burjassot, Spain Mercury toxicity is highly dependent on its chemical form. Methylmercury (MeHg), the most toxic chemical specie of the element, is a neurotoxic agent that affects the development of the nervous system, resulting in psychological disturbance, impaired hearing, loss of sight, ataxia, loss of motor control and neural debilitation. There are abundant data and advisories for MeHg levels in seafood products, the major source of MeHg exposure for humans. The aim of this work is to evaluate the effects of MeHg on the essential cell survival processes of Caco2 cells, a widely accepted model of intestinal epithelia – the first physiological barrier for exogenous toxicants towards systemic blood circulation. Caco-2 cells are seeded onto polycarbonate filters, placed into 24-well plates and grown for 15 days until morphological and functional differentiation. Cell cultures are incubated for 24 h with MeHg at different concentrations (0.125, 0.5, and 1.5 M). To monitor energetic cell metabolism, MTT conversion is estimated. Mitochondrial membrane potential (∆ψm) is evaluated as an early indicator of induced apoptosis. To estimate alterations on cell biology, total RNA and DNA contents are identified histochemically by their differential stainability with pyronin Y and Hoechst 33342 fluorochromes respectively. After cell exposure, MTT assays suggest that at the concentrations assayed, MeHg has no inhibitory effects on mitochondrial enzyme function. However, ∆ψm is altered in those cultures exposed to MeHg 1.5 M. In addition, changes in cell cycle phases and RNA contents suggest alterations of cell signaling pathways and cell biology. Due to the physiological importance of intestinal epithelia as the main site of absorption, the understanding of MeHg effects on this epithelia could contribute to a better estimation of health-risk assessment associated with the ingestion of MeHg contaminated foods. doi:10.1016/j.toxlet.2006.06.337
It follows from our results that the synthesis of pterin derivatives, i.e. neopterin and biopterin, is influenced by diverse stress factors. Neopterin and biopterin serum concentrations may thus provide additional information on the influence of stress factors on the porcine organism in vivo, and, at the same time, they extend the modest list of papers on pterins in veterinary practice.
S161
This project was supported by grant PO2 ES09601 from the National Institutes of Environmental Health Sciences (NIEHS), NIH and EPA R826886 from the U.S. Environmental Protection Agency. Its contents are the responsibility of the authors and do not necessarily represent the official views of the NIEHS, NIH or EPA. doi:10.1016/j.toxlet.2006.06.334
doi:10.1016/j.toxlet.2006.06.333 P10-16 Lessons learned from longitudinal studies to identify high exposure groups using OP pesticide urinary biomarkers Elaine M. Faustman, William C. Griffith, Eric Vigoren University of Washington, Washington, United States We reanalyze data on a urinary biomarker, TCP a metabolite of an organophosphate pesticide (OP) chlorpyrifos in two populations to understand issues in identifying highly exposed individuals. The studies being reanalyzed are two population-based samples, one of 79 persons from Maryland over a 12-month period and the other of 90 persons from Minnesota over a 4-day period. Both data sets have longitudinal measurements of urinary metabolites so that within and between person variances can be estimated after accounting for any major temporal trends and effects of other important covariates, such as gender and age. An important feature of the between and within person variances emerged from the analysis is that the within person variance is larger than the between person variance in both populations. The large within person variance makes it difficult to identify which individuals are most highly exposed in these populations. For example, if you try to identify individuals in the upper 10% of the population, only 20–30% would be correctly identified after a single measurement and 65–75% after 20 measurements. A similar pattern of large within person variability compared to between person variability has been observed in a study of diakyl metabolites in urine of 44 children of farmworkers in the Yakima Valley of Washington over a 21 month period. This suggests that in similarly exposed populations it will be difficult to conduct epidemiological studies of diseases associated with higher exposure because of exposure misclassification. The large within person availability also suggests that future studies should include multiple measurements on the same person so that estimates of the between person variability be made to describe the population variability in exposure. Estimates of the population variability are useful for probabilistic risk assessment of cumulative exposures.
P10-17 Urinary biomarkers of aflatoxin exposure in young children in Egypt and Guinea Nektaria Polychronaki 1 , Christopher Wild 2 , Hannu Mykk¨anen 1 , Mosaad Abdel-Wahhab 3 , Abdoulaye Sylla 4 , Mamadou Diallo 4 , Hani El-Nezami 1 , Paul Turner 2 1 University
of Kuopio, Finland; 2 University of leeds, Leeds, UK; 3 National Research centre, cairo, Egypt; 4 Institut Pasteur de Guinee, Kindia Chronic exposure to the fungal toxins aflatoxins (AFs) is considered to be a major risk factor in the development of primary liver cancer. In parts of Africa AF exposure is common and early life exposure could be a contributing factor towards the early onset of liver cancer in adulthood. This project assessed the level of exposure of children to aflatoxin in Egypt (predicted moderate aflatoxin exposure) and Guinea (predicted high aflatoxin exposure) by measurement of AF metabolites in urine. Aflatoxins were extracted from urine samples of 50 Egyptian (aged 1–1.5 years) and 50 Guinean children (aged 2–4 years) by C18 cartridges and aflatoxin immunoaffinity columns and analyzed by HPLCfluorescence. AFB1, AFB2, AFG1, AFG2 and AFM1 were detected in children’s urine and the identities of the aflatoxins were confirmed by spiking with aflatoxin standards and co-chromatography using different HPLC conditions. AF were less frequently present in Egyptian than Guinean children (38% versus 86%) with statistically significant differences in prevalence for most of the detected toxins (AFB1 (2% versus 16%, p = 0.016), AFB2 (10% versus 58%, p = 0.000), AFG1 (4% versus 2%), AFG2 (24% versus 36%, p = 0.190) and AFM1 (8% versus 64%, p = 0.000). For AFM1 the mean levels in Guinea were 18-fold higher than in Egypt. Worldwide there is a scarcity of urinary biomarker data for AF exposure in children. The lower frequencies of both AFB1 and AFG1 in the urine mostly likely reflect conversion of the dietary AF to other metabolites in the liver. Overall AF exposure in Egypt is modest in compar-
S162
Abstracts / Toxicology Letters 164S (2006) S1–S324
ison to Guinea though it should be noted that more of the Egyptian children in this study were still at least partially breast feeding, and thus may be protected against exposure due to the limited passage of AF into breast milk. These data would suggest that measures to reduce AF exposure in both regions are important although the situation is particularly pressing in Guinea where exposure is more prevalent and at higher levels. doi:10.1016/j.toxlet.2006.06.335 P10-18 The verification of the “drug addictive” status in drug abuse legal cases in Greece M.A. Savvopoulos 1 , M.N. Tzatzarakis 2 , M. Toutoudaki 2 , M. Christaki 2 , E. Pallis 2 , A.M. Tsatsakis 2 1 Center
of Toxicological Sciences and Research, Department of Medicine, University of Crete, Heraklion, Greece; 2 Center of Toxicological Sciences and Research, Department of Medicine, University of Crete, Heraklion, Greece The Court should decide whether the defendant is a drug addict or a simple user. The law demands an expert report (i.e. medical, psychiatric, clinical, toxicological or other, e.g. segmental hair testing) to be conducted. One hundred and twenty five legal cases related to the judicial verification of drug dependence and over than 2500 expert reports conducted by the medical examiner were studied. Information from each file about the process, the decision, the police record, the indictment, the expert reports, the defendant’s individuality, the crimes, the penal confrontal, etc. were classified into 11 groups. Conclusions on the kind of the expert report, the evident value of each kind of the expert reports, are presented. The following procedure is compared to the rightful procedure. Three legal cases and three expert reports were methodically examined and analytically presented. The expert report is not committing for the Court. The District Attorney is allowed to choose the kind of the expert report to be done. The kind of the report depends on the available technostructure and human resources. Evaluation of the nine common scientific criteria of addiction is presented. The chronic frames and the examination by several experts are impossible to be kept to. Hair testing is accepted in Court, although is not specially refereed in any Law. doi:10.1016/j.toxlet.2006.06.336
P10-19 Evaluation of methylmercury cytotoxicity at intestinal level S. Torres 1 , M.J. Laparra 2 , V. Devesa 1 , D. V´elez 1 , R. Barber´a 2 , R. Montoro 1 , R. Farre 2 1 Instituto
de Agroqu´ımica y Tecnolog´ıa de Alimentos (IATA-CSIC), Aptdo 73, 46100 Burjassot, Valencia, Spain; 2 Nutrition and Food Chemistry, Faculty of Pharmacy, University of Valencia, Avda. Vicente Andr´es Estell´es s/n, 46100 Burjassot, Spain Mercury toxicity is highly dependent on its chemical form. Methylmercury (MeHg), the most toxic chemical specie of the element, is a neurotoxic agent that affects the development of the nervous system, resulting in psychological disturbance, impaired hearing, loss of sight, ataxia, loss of motor control and neural debilitation. There are abundant data and advisories for MeHg levels in seafood products, the major source of MeHg exposure for humans. The aim of this work is to evaluate the effects of MeHg on the essential cell survival processes of Caco2 cells, a widely accepted model of intestinal epithelia – the first physiological barrier for exogenous toxicants towards systemic blood circulation. Caco-2 cells are seeded onto polycarbonate filters, placed into 24-well plates and grown for 15 days until morphological and functional differentiation. Cell cultures are incubated for 24 h with MeHg at different concentrations (0.125, 0.5, and 1.5 M). To monitor energetic cell metabolism, MTT conversion is estimated. Mitochondrial membrane potential (∆ψm) is evaluated as an early indicator of induced apoptosis. To estimate alterations on cell biology, total RNA and DNA contents are identified histochemically by their differential stainability with pyronin Y and Hoechst 33342 fluorochromes respectively. After cell exposure, MTT assays suggest that at the concentrations assayed, MeHg has no inhibitory effects on mitochondrial enzyme function. However, ∆ψm is altered in those cultures exposed to MeHg 1.5 M. In addition, changes in cell cycle phases and RNA contents suggest alterations of cell signaling pathways and cell biology. Due to the physiological importance of intestinal epithelia as the main site of absorption, the understanding of MeHg effects on this epithelia could contribute to a better estimation of health-risk assessment associated with the ingestion of MeHg contaminated foods. doi:10.1016/j.toxlet.2006.06.337