Chem. Res. Toxicol. 2008, 21, 2067–2068
2067
In Memoriam: Kazuo T. Suzuki, Ph.D. Kazuo T. Suzuki, Professor Emeritus in the Department of Toxicology and Environmental Health of the Graduate School of Pharmaceutical Sciences at Chiba University, Japan, and an internationally recognized authority on metal toxicology, died unexpectedly on July 15, 2008. Kazuo Suzuki was born on February 14, 1943, in Osaka. He obtained a B.Sc. Degree from the University of Tokyo and his first Ph.D. degree (Pharmaceutical Sciences) from this institution in 1971. After two postdoctoral years at SRI International in California, he joined the National Institute of Environmental Sciences in Tsukuba, Japan. While there, he obtained a second Ph.D. degree (Medical Sciences) from the University of Tokyo in 1981 and a third from the Tokyo Institute of Technology (Sciences) in 1986. He was appointed Professor at Chiba University in 1992 where he trained 16 Ph.D. students. He attained emeritus status in March 2008. Over the course of his career, he published more than 300 original papers and 50 review articles and authored or coauthored more than 40 books or book chapters. He was a member of the Society of Toxicology (United States), the Pharmaceutical Society of Japan, the Japanese Biochemical Society, the Japan Society for Biomedical Research on Trace Elements, the Japanese Society of Toxicological Sciences, and the Japanese Society for Hygiene. He served on the editorial boards for seven peer-reviewed journals. He was repeatedly honored by his colleagues for his achievements. He received the Young Scientist Award of the Pharmaceutical Society of Japan (1982), the Mochida Foundation Academic Award (1991), the Senji Miyata Foundation Research Award (1995), the Klaus Schwarz Commemorative Medal of the International Association of Bioinorganic Scientists (2007), and the Award of Japanese Society of Biological Research on Trace Elements (2007). He was elected an honorary foreign member of the Bulgarian Academy of Medicine in 1998. Professor Suzuki’s career was distinguished by his persistence and success in the application of novel analytical techniques to understanding the metabolism and biological effects of various metal and metalloids. His early work on metallothionein occurred during the years when there was great interest in understanding the role of this protein in the metabolism and toxicity of cadmium. His 1980 paper in Analytical Biochemistry [(1980) 102, 31-34] that described the use of high-performance liquid chromatography (HPLC) and atomic absorption spectrometry to separate and quantify metals bound to metallothio-
neins marked the beginning of the widespread use of this technique to study the roles of this protein in the metabolism of cadmium, zinc, and copper. Later, he and his colleagues modified this approach and used inductively coupled plasma (ICP) and a UV monochromatometer as a multielement specific detector [(1987) J. Chromatogr. 400, 233-240]. In 1995, his group described the use of stable isotopes as tracers of the metabolism and disposition of metals using HPLC-ICP-mass spectrometry (MS) for separation and quantitation [(1995) J. Chromatogr. B 670, 63-71]. Using these novel approaches, Professor Suzuki and his colleagues contributed to our understanding of the molecular events that underlie the intracellular fate and toxicity of cadmium. In recent years, Professor Suzuki and his collaborators expanded their research to include selenium and arsenic. They used MS to identify a novel selenium metabolite, Se-methylN-acetylselenohexosamine, in rat urine [(2002) J. Chromatogr. B 767, 301-312). Subsequent work showed that the major urinary selenium metabolite within the nutritionally sufficient to low-toxic exposure range was a selenosugar [(2002) Proc. Natl. Acad. Sci. U.S.A. 99, 15932-15936]. This work was an important addition to our understanding of the dosage dependency of selenium metabolism. In a technical tour de force, Professor Suzuki and his colleagues used three stably labeled selenium compounds (76Se-methylselenocysteine, 77Se-selenomethionine, and 82Se-selenite) and HPLC-ICP-MS to track the metabolic fate of each compound in the rat [(2006) Toxicol. Appl. Pharmacol. 217, 185-195]. This approach makes it possible to quantify relative contributions of each compound to overall metabolism and should be an impetus to much further work on selenium, including studies in humans. Equally significant were Professor Suzuki’s contributions to the study of arsenic metabolism. In recent years, he and his colleagues were among the first to identify methylarsonous and dimethylarsinous acid as urinary metabolites in humans [(2001) Chem. Res. Toxicol. 14, 371-378] and to demonstrate peculiar interspecies differences in the distribution and binding of dimethylarsinousacid[(2001)Chem.Res.Toxicol.14,1446-1452]. His group also identified dimethylthioarsenic (DMTA) as an important metabolite [(2004) Chem. Res. Toxicol. 17, 914-921]. In subsequent work, the Suzuki group showed that DMTA was more cytotoxic than oxoarsenicals that contain pentavalent arsenic (arsenate, dimethylarsinic acid) and that it perturbed
10.1021/tx800314q CCC: $40.75 2008 American Chemical Society Published on Web 11/17/2008
2068
Chem. Res. Toxicol., Vol. 21, No. 11, 2008
progression in the cell cycle [(2007) Chem. Res. Toxicol. 20, 1120-1125]. In their most recently published work, he and his colleagues provided new details about the formation of thioarsenicals in cells [(2008) Toxicol. Appl. Pharmacol. 227, 309-399] and laid the foundation for a chemically plausible pathway for their formation [(2008) Chem. Res. Toxicol. 21, 550-553; (2008) Toxicol. Appl. Pharmacol., in press]. This work should serve as a basis for a range of experimental and theoretical studies on the formation and action of this class of arsenic metabolites. Finally, Professor Suzuki’s contribution to the new field of metallomics should not be overlooked. His paper on the metabolomics of arsenic [(2005) Anal. Chim. Acta 540, 71-76] is a prospectus for metallome research that will guide future research on this element. It is our loss that he will not be here to contribute to this work. Professor Suzuki was well-known to colleagues worldwide for his kindness and humility. He was always a gracious host and a welcome visitor. He is survived by his wife Yoko, who accompanied him on many trips abroad, and by two sons. He will be sorely missed. Acknowledgment. We thank our colleagues for sharing their recollections of Professor Suzuki. Professor Yasumitsu Ogra
of Chiba University graciously provided many biographical details. This manuscript has been reviewed in accordance with the policy of the National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, and has been approved for publication. Approval does not signify that the contents necessarily reflect the views and policies of the Agency nor does mention of trade names or commercial products constitute endorsement or recommendation for use. David J. Thomas* Experimental Toxicology DiVision National Health and EnVironmental Effects Research Laboratory Office of Research and DeVelopment U.S. EnVironmental Protection Agency 109 Alexander DriVe Research Triangle Park, North Carolina 27711 E-mail:
[email protected] Miroslav Styblo Department of Nutrition UniVersity of North Carolina at Chapel Hill Chapel Hill, North Carolina 27599 TX800314Q
