Martínez, M. E., Thompson, P., Jacobs, E. T., Giovannucci, E., Jiang, R., Klimecki, W., & Alberts, D. S. (2006). Dietary factors and biomarkers involved in the methylenetetrahydrofolate reductase genotype-colorectal adenoma pathway. Gastroenterology, 131(6), 1706-16.
Methylenetetrahydrofolate reductase (MTHFR) is involved in intracellular folate homeostasis and metabolism. We assessed 2 polymorphisms in the MTHFR gene (C677T and A1298C) in relation to colorectal adenoma recurrence and conducted analyses to investigate their joint effects with plasma and dietary markers of folate status.
Beamer, P., Klimecki, W., Loh, M., Van Horne, Y. O., Sugeng, A., Lothrop, N., Billheimer, D., Guerra, S., Lantz, R. C., & Martinez, F. (2016). Association of Children’s Urinary CC16 Levels with Arsenic Concentrations in Multiple Environmental Media. International Journal of Environmental Research and Public Health, 13(5), E521. doi:10.3390/ijerph13050521
BIO5 Collaborators
Walter Klimecki, Clark Lantz
Meza, M. M., Yu, L., Rodriguez, Y. Y., Guild, M., Thompson, D., Gandolfi, A. J., & Klimecki, W. T. (2005). Developmentally restricted genetic determinants of human arsenic metabolism: association between urinary methylated arsenic and CYT19 polymorphisms in children. Environmental health perspectives, 113(6), 775-81.
We report the results of a screen for genetic association with urinary arsenic metabolite levels in three arsenic metabolism candidate genes, PNP, GSTO, and CYT19, in 135 arsenic-exposed subjects from the Yaqui Valley in Sonora, Mexico, who were exposed to drinking water concentrations ranging from 5.5 to 43.3 ppb. We chose 23 polymorphic sites to test in the arsenic-exposed population. Initial phenotypes evaluated included the ratio of urinary inorganic arsenic(III) to inorganic arsenic(V) and the ratio of urinary dimethylarsenic(V) to monomethylarsenic(V) (D:M). In the initial association screening, three polymorphic sites in the CYT19 gene were significantly associated with D:M ratios in the total population. Subsequent analysis of this association revealed that the association signal for the entire population was actually caused by an extremely strong association in only the children (7-11 years of age) between CYT19 genotype and D:M levels. With children removed from the analysis, no significant genetic association was observed in adults (18-79 years). The existence of a strong, developmentally regulated genetic association between CYT19 and arsenic metabolism carries import for both arsenic pharmacogenetics and arsenic toxicology, as well as for public health and governmental regulatory officials.
Meza-Montenegro, M. M., Gandolfi, A. J., Santana-Alcántar, M. E., Klimecki, W. T., Aguilar-Apodaca, M. G., Del Río-Salas, R., De la O-Villanueva, M., Gómez-Alvarez, A., Mendivil-Quijada, H., Valencia, M., & Meza-Figueroa, D. (2012). Metals in residential soils and cumulative risk assessment in Yaqui and Mayo agricultural valleys, northern Mexico. The Science of the total environment, 433, 472-81.
This investigation examines the extent of soil metal pollution associated with the Green Revolution, relative to agricultural activities and associated risks to health in the most important agricultural region of Mexico. Metal contents in bulk soil samples are commonly used to assess contamination, and metal accumulations in soils are usually assumed to increase with decreasing particle size. This study profiled the spatial distribution of metals (Ni, Cr, Pb, Cu, Fe, Cd, V, Hg, Co, P, Se, and Mn) in bulk soil and fine-grained fractions (soil-derived dust) from 22 towns and cities. The contamination of soil was assessed through the use of a geoaccumulation index (Igeo) and pollution index (PI). The results of this study indicated that a number of towns and cities are moderately to highly polluted by soil containing Be, Co, Hg, P, S, V, Zn, Se, Cr, and Pb in both size fractions (coarse and fine). Hazard index in fine fraction (HI(children)=2.1) shows that risk assessment based on Co, Mn, V, and Ni spatially related to power plants, have the potential to pose health risks to local residents, especially children. This study shows that risk assessment based on metal content in bulk soil could be overestimated when compared to fine-grained fraction. Our results provide important information that could be valuable in establishing risk assessment associated with residential soils within agricultural areas, where children can ingest and inhale dust.
Loh, M. M., Sugeng, A., Lothrop, N., Klimecki, W. -., Wilkinson, S., & Beamer, P. -. (2014). Multimedia Exposures to Arsenic and Lead for Children in a Community Near a Former Mine Tailings and Smelter Site. Environmental Research.
