Stephen A. Benjamin
Professor Emeritus

Phone: 491-6144
Fax: 491-0603
Email: Stephen.Benjamin@colostate.edu
Office: Pathology Building

 

Degrees

• AB, Brandeis University, 1960
• DVM, cornell University, 1964
• PhD, Cornell University, 1968

Board Certifications

• Diplomate, American College of Veterinary Pathologists, Anatomic Pathology

Research Interests

• Dr. Benjamin studies the toxic effects of chemical and physical environmental agents, including organic and inorganic chemicals and ionizing radiation, with an emphasis on carcinogenesis. His current investigations focus on chemical mixtures with a goal of understanding toxic interactions between different agents on hepatic injury and carcinogenesis. Long-term goals include working with an interdisciplinary team to develop predictive models for environmental health risk assessment. Studies of promotion of preneoplasia and neoplasia focus on understanding the roles of cell proliferation and free radical injury. Research techniques used include cell culture, immunohistochemistry, computer-assisted histomorphometry, analytical chemistry, and molecular biological investigations of growth factors and DNA injury. Other research involves the effects of prenatal and early postnatal irradiation on developmental, non-neoplastic, and neoplastic diseases in beagle dogs and studies of the etiology and pathogenesis of canine mammary cancer.

Selected Publications

Pub Med for Benjamin SA.

• Benjamin, S.A., Lee, A.C., and Saunders, W.J. Classification and behavior of canine mammary epithelial neoplasms based on life-span observations in beagles. Vet. Pathol. 36:423-436 (1999).
• Benjamin, S.A., R.S.H. Yang, J.D. Tessari, L.W. Chubb, M.D. Brown, C. E. Dean, Jr., and T.J. Keefe. Lack of promotional effects of groundwater contaminant mixtures on the induction of preneoplastic foci in rat liver. Toxicology, 137:137-149 (1999).
• Gustafson, D.L., Thomas, R.S., Long, M.E., Benjamin, S.A., and Yang, R.S.H. Comparative hepatocarcinogenicity of hexachlorobenzene, pentachlorobenzene, 1,2,4,5-tetrachlorobenzene, and 1,4-dichlorobenzene: Application of a medium-term liver focus bioassay and molecular and cellular indices. Toxicol. Sci.53:245-252 (2000).
• Thomas, R.S., Conolly, R.B., Gustafson, D.L., Long, M.E., Benjamin, S.A., and Yang, R.S.H. A physiologically-based pharmacodynamic analysis of hepatic foci within a medium-term liver bioassay using pentachlorobenzene as a promoter and diethylnitrosamine as an initiator. Toxicol. Appl. Pharmacol. 166:128-137 (2000).
• Pott,W.A., Benjamin,S.A., and Yang,R.S.H. Pharmacokinetics, metabolism, and carcinogenicity of arsenic. Rev. Environ. Contam. Toxicol. 169:165-214 (2001).
• Benjamin, S.A. Epithelial mammary neoplasia in beagles: Lifetime morbidity and mortality. In, Pathobiology of the Aging Dog, Mohr, U., Carlton, W.W., Dungworth, D.L., Benjamin, S.A., Capen, C.C., and Hahn, F.H., Eds., pp. 179-187, Iowa State University Press, Ames, 2001.
• Barnes, T., Benjamin, S.A., and Hahn, F.F. Age-related changes in the structure and function of the thyroid gland. In, Pathobiology of the Aging Dog, Mohr, U., Carlton, W.W., Dungworth, D.L., Benjamin, S.A., Capen, C.C., and Hahn, F.H., Eds., pp. 247-254, Iowa State University Press, Ames, 2001.
• Muggenberg, B.A., Hahn, F.F., and Benjamin, S.A. Cause of mortality in laboratory beagle colonies. In, Pathobiology of the Aging Dog, Mohr, U., Carlton, W.W., Dungworth, D.L., Benjamin, S.A., Capen, C.C., and Hahn, F.F., Eds., pp. 247-254, Iowa State University Press, Ames, 2001.
• Benjamin, S.A., B.E. Powers, F.F. Hahn, and D.F. Kusewitt. Radiation and Heat. In, Handbook of Toxicologic Pathology, 2nd Edition, Eds, M.A.Wallig,W.M. Haschek and C.G. Rousseaux, Academic Press Inc., San Diego, CA, pp. 529-594 (2001).
• C.E. Dean, Jr., S. A. Benjamin, L. S. Chubb, J. D. Tessari and T. J. Keefe. Nonadditive Hepatic Tumor Promoting Effects by a Mixture of Two Structurally Different Polychlorinated Biphenyls in Female Rat Livers. Toxicological Sciences 66:54-61, 2002.