Our research interest revolves around Molecular Toxicology. We are involved in two main areas of research:
A. Gene Discovery: Most of the research in this area involves theuse of state of the art molecular biology techniques such as the commonly known Differential Display Reverse Transcription -PCR (DDRT-PCR technique which identifies differentially expressed mRNA species; 5′ RACE PCR (for the isolation of full length cDNAs) and the use of Panhandle PCR (to retrieve genomic segments flanking a known DNA sequence (obtained from the full length cDNA).
These techniques are being employed to isolate genes that are regulated by immunosuppressive drugs such as Dexamethasone and an antiglucocorticoid compound, Pregnenolone-16-a-carbonitrile. It is joint collaborative effort with Dr. Philip Guzelian (Univ. of Colorado). The ultimate goal of this research is to identify and study the regulation of new genes that may be associated with metabolism of xenobiotic compounds including environmental pollutants.
This same approach is being used to isolate and identify genes that are associated with cancer (oncogenes). Most of the works performed on colorectal cancer oncogenes have been done on Caucasian and Japanese population, with little or no representation of the Hispanic population. Our research proposes to identify specific genes and isolate cDNA probes for colon cancer genes that may be expressed in the cancer patients from the Hispanic population and can eventually be used for diagnostics and treatment of cancer.
B. Environmental Toxicology: We are interested in identifying and studying genes that are affected by environmental pollutants (particularly from air). In collaboration with Dr. Carmen L. Cadilla
(UPR-MSC) and Dr. Ben Van Houten (Galveston, Tx) we are developing technologies to evaluate DNA integrity (Genotoxicity) using molecular toxicology techniques such as quantitative XL-PCR. We are studying DNA damage caused by pollutants in mitochondrial and nuclear DNA. The ultimate goal of this research is to develop a sensitive bioassay which could be used to evaluate environmental exposure in different populations.
Jaime F. Puig-Hernández, PhD. and Braulio D. Jiménez-Velez, PhD. HPLC Determination of the Concentration and Integrity of L-Thyroxine (T4) in Free T4 Stock Solution. Puerto Rico Health Sciences Journal, 24:No2, 151-156 (2005).
Mónica I. Torres-Pérez , MS; Braulio D. Jiménez-Velez, PhD; Imar Mansilla-Rivera, PhD, Carlos J. Rodríguez-Sierra, PhD. Effect of three extraction techniques on sub mitochondrial particle and Microtox bioassays by airborne particulate matter. Puerto Rico Health Science Journal 24:No.1, 35-39 (2005).
K. Kientz, B. D. Jiménez, L. Pérez, C. J. Rodríguez-Sierra In Vitro Bioaccessibility of Metals in Soils from a Superfund Site in Puerto Rico Bull. Environ. Contam. Toxicol. 70:927-934 (2003). B.D. Jimenez, L. Maldonado, R.H. Dahl, L.C. Quattrochi, P.S. Guzelian. Ectopic Expression of MHC Class II Genes (RT1.B (I) (a & b) in Rat Hepatocytes in vivo and in Culture Can be Elicited by Treatment with the Pregnane X Receptor Agonists Pregnenolone 16a-Carbonitrile and Dexamethasone. Life Sci. 71:(3), pp. 311-323, 7 June, 2002 .
Alan M. Preston, Fred B. Bercovitch, Braulio D. Jimenez, José F. Rodríguez Orengo, Wilfredo Delgado Morales, Cindy A. Rodríguez, Manuel R. Lebrón and Cynthia E. Rivera. Plasma homocysteine concentrations in a population of Rhesus Monkeys (Macaca mulatta): reference ranges and accompanying plasma concentrations of folate and Vitamin B12. Contemporary Topics (41) No.1 pp 28-30. 2002.
Carlos J. Rodríguez and Braulio D. Jiménez. Trace Metals in Striped Moharra (Diapterus plumierri) Fish from Puerto Rico . Mar.Pollution Bull. 44: (10) pp. 1039-1045. (2002).
José L. Roig-López, Pedro Santiago, Carlos Santiago, Braulio Jiménez and José E. GarcÃŒa-Arraras. Strategies to identify differentially expressed genes during regeneration. .Echinoderms 2000, Baker (ed.) , Swelts & Zeitlinger, Lisse, ISBN 90 5809189 9 (2001). 25. Ulda. J. Pérez, B.
Jiménez, W. Delgado, and C. J. Rodríguez-Sierra. Heavy Metals in the False Mussel, Mytilopsis domingensis, fromTwo Tropical Estuarine Lag. Bull. Environ. Contam. Toxicol. 66:206-213 (2001).
Darwin Reyes, Osvaldo Rosario, José F. Rodríguez, and Braulio Jiménez. Toxic Evaluation of organic extracts from airborne particulate matter in Puerto Rico . Environ. Health Persp. 108: (7) 635-640 (2000). 23. P. Melendez, N. Longo B.D. Jiménez and C.L. Cadilla. Insulin induced gene 33 mRNA expression in CHO cells is insulin receptor dependent. J. Cell Biochem, 77 (3): 432-444 (2000).
Braulio D. Jiménez, L.C. Quattrochi, C.B. Yockey, and P.S. Guzelian. Identification by Differential Display of the IF1 Inhibitor Peptide of ATP Synthase/ATPase as a Gene Inducible in Rat Liver by Pregnenolone 16(-Carbonitrile. Life Sciences 67 17: 1825-1832 (2000).
Clark, J.T., B.D. Jiménez, S.L. Evans, R.Barrow, M. Winfree, and J.J. Morotek. 1994. Cadmium-induced sexual dysfunction does not involve increased hepatic metabolism nor increased corticosterone. Physiology and Behavior 56(5):975-981.
Oikari, A, and B.D. Jiménez, 1992. Effects of hepatotoxicants on the induction of microsomal monooxygenase activity in sunfish liver by ÃŸ-naphtoflavone and benzo(a)pyrene. Ecotox. Environ. Safety 23:89-102.
McCarthy, Shugart, L.R., and B.D. Jimenez, 1992. Biomarker-based biomonitors for evaluating health and ecological effects of environmental contaminants. In:Hazardous Waste Site Investigations: Towards Better Decisions. editors R.B. Gamage, and B.A. Berven, Lewis Publ. Inc., Boca Raton, Fl. 177-207.
Shugart, L. R., Jiménez, B. D. and McCarthy J. F. 1991. DNA Damage as a Biological Marker in Aquatic Organisms exposed to Benzo[a]pyrene. In: Eleventh International Symposium on Polynuclear Aromatic Hydrocarbons, edited by W.E. May and M. Cooke. Batelle Press, Columbus, OH pp 839-846.
Jiménez, B. D., 1990. Laboratory and field responses in the bluegill sunfish (Lepomis sp.) In: Biological Markers of Environmental Contaminants. Ed. J.F. McCarthy and L. R. Shugart. American Chemical Society, Washington DC. pp 123-142.
Jiménez, B. D. and J.J. Stegeman, 1990. Detoxication enzymes as indicators of stress. Trans. Amer. Fish. Soc. 8: 67-79.
Jiménez, B. D. and L. S. Burtis, 1989. Influence of environmental variables on the hepatic mixed function oxidase system in the bluegill sunfish, (Lepomis Macrochirus). Comp. Biochem. Physiol. 93C: No.1 11-21.
Jiménez, B. D. and L. S. Burtis, 1988. Response of the mixed function oxidase system to toxicant dose, food and acclimation temperature in the bluegill sunfish. Marine Environ. Res. 24:45-49.
Jiménez, B. D., G. H. Ezell, B. Z. Egan, N. E. Lee, and J. F. McCarthy, 1988. Effects of environmental variables on the mixed function oxidase (MFO) in bluegills (Lepomis macrochirus). Environ. Toxicol. Chem. 7:623-634.
Jiménez, B. D., C. P. Cirmo, and J. F. McCarthy, 1987. Uptake elimination and metabolism of Benzo(a)pyrene in bluegill sunfish ( Lepomis macrochirus). Aquat. Toxicol. 10:41-57.
McCarthy, J. F., and B. D. Jiménez. 1985. Reduction in bioavailability to bluegills of polycyclic aromatic hydrocarbons bound to dissolved humic material. Environ. Toxicol. Chem. Vol 4. pp. 511-521.