Research: A Citation Profile Of David Baltimore, Rockefeller University's New President

The institution that David Baltimore will guide in the coming years has a well-earned reputation as one of the world's best biomedical research establishments. But is Rockefeller University still riding high, or is it resting on its laurels? According to data from the Science Citation Index (SCI) of the Philadelphia-based Institute for Scientific Information (ISI), Rockefeller University is not only maintaining its dominant position, but also moving ahead. The accompanying chart illustrates the average citations per paper from Rockefeller University relative to the average for all science papers produced in the United States (which represents a baseline to control for changes in the size of the database over the years). The period surveyed, 1973-88, is divided into a dozen overlapping five-year intervals, each of which includes papers published in those five years and citations to those papers during the same five years. Although slipping slightly in the early 1980s, Rockefeller has more than recovered. In the most recent period (1984-88), papers from Rockefeller scientists were cited an average of 15.2 times each. By contrast, the average number of citations for U.S. papers over the same period was 5.5. That's 2.8 citations for every Rockefeller paper to one for the average U.S. paper - the highest citation impact Rockefeller papers have exhibited in two decades. Since Rockefeller emphasizes research in cell and molecular biology, genetics, and immunobiology - all fields with higher average rates of citation than, say, organic chemistry, geophysics, or mathematics - it is not surprising to find a citations-per-paper average for Rockefeller some 180 percent higher than the average for all U.S. science. However, Rockefeller comes out on top in citation impact even when compared with U.S. universities that similarly emphasize biological and biomedical research, such as the University of California, San Francisco. In fact, among the 100 highest-impact universities in the U.S., Rockefeller ranked first for 1973-88, as well as for the period 1981-88, ISI's Research Department recently determined. The chart on page 16 represents a survey of some 7,800 cited papers from Rockefeller scientists. Thirty-seven of those papers turned out to be cited 400 times or more, which, according to ISI's criteria, qualifies them for citation classic status. --D.P. This month David Baltimore assumes the presidency of Rockefeller University. It's a homecoming for Baltimore, who was a student at the university in the early 1960s. After earning his Ph.D. there in 1964, Baltimore held a series of appointments at the Albert Einstein College of Medicine, in New York City (1964-65), the Salk Institute, in La Jolla, Calif. (1965-68), and the Massachusetts Institute of Technology, in Cambridge (1968-90). Until last month he was also director of the Whitehead Institute for Biomedical Research in Cambridge, a post he had held since 1982. While at the Whitehead, Baltimore juggled administrative, teaching, and research duties - a skill he will no doubt refine to an even greater degree as president of Rockefeller (see accompanying story). The Scientist decided to look at the research that has helped take Baltimore this far, and to do so from the perspective of his overall citation record and his most highly cited papers (see accompanying table). Baltimore, now 52, is among the world's most frequently cited scientists - no surprise to readers of The Scientist, since his name has appeared near the top of the newspaper's "Citation Superstars" columns recently. For the period 1965 to 1978, his works collected 6,773 explicit citations in journals indexed in the Philadelphia-based Institute for Scientific Information's (ISI) Science Citation Index (SCI), which made Baltimore the 66th most-cited scientist in the world (The Scientist, March 19, 1990, page 22). He has been moving up in rank ever since. For the period 1973-84, his publications attracted 10,150 citations, which was good for 32nd place in the world standings (The Scientist, Feb. 19, 1990, page 22). And for the most recent period surveyed, 1981-88, he collected 7,574 citations from his colleagues. Thus, according to ISI's data, Baltimore is now the world's 26th most-cited scientist. For the three periods, his average citations per year were 484, 846, and 947, respectively. Rank Paper Total Citations Through 1989 1. D. Baltimore, "Viral RNA-dependent DNA polymerase," Nature, 226:1209, 1970 1,159 2. R. McCaffrey, T.A. Harrison,R. Parkman, D. Baltimore, "Terminal deoxynucleotide transferase activity in human leukemic cells and in normal human thymocytes," New England Journal of Medicine, 292:775, 1975421 3. O.N. Witte, D. Baltimore, A. Dasgupta, "Abelson murine leukemia virus protein is phosphorylated in vitro to form phospho- tyrosine," Nature, 283:826, 1980403 4. H.M. Temin, D. Baltimore, "RNA-directed DNA synthesis and RNA tumor viruses," Advances in Virus Research, 17:129, 1972378 5. A.S. Huang, D. Baltimore, "Defective viral particles and viral disease processes," Nature, 226:325, 1970356 6. D. Baltimore, A.S. Huang, M. Stampfer, "Ribonucleic acid synthesis of vesicular stomatitis virus. II. An RNA polymerase in the virion,"Proceedings of the National Academy of Sciences, USA, 66:572, 1970332 7. D. Baltimore, "Gene conversion: Some implications for immunoglobulin genes," Cell, 24:592, 1981327 SOURCE: ISI's Science Citation Index Baltimore has published at least a dozen papers cited more than 300 times and no fewer than five dozen cited more than 100 times each. The paper that brought him fame and his Nobel Prize in 1975 (he shared the prize with Howard M. Temin, University of Wisconsin, Madison, and Renato Dulbecco, the Salk Institute, La Jolla, Calif.) was the discovery report of reverse transcriptase: "Viral RNA-dependent DNA polymerase," Nature, 226:1209-11, 27 June 1970. According to the SCI, this paper has received more than 1,150 citations since its publication and is Baltimore's most-cited paper. In this paper, Baltimore announced a startling finding - that RNA viruses could make copies of themselves. Until then it was thought that genetic information was transmitted only from DNA to RNA and never in the reverse order (hence the name "reverse transcriptase" for the enzyme that allows for duplication of viral genes into DNA). What Baltimore found in Moloney murine leukemia virus, Temin and Satoshi Mizutani independently discovered in Rous sarcoma virus (see H.M. Temin, S. Mizutani, "RNA-dependent DNA polymerase in virions of Rous sarcoma virus," Nature, 226:1211-3, 27 June 1970). The Temin-Mizutani paper, which has received 1,193 citations, appeared immediately after Baltimore's paper in the same issue of Nature. The year-by-year citation history of their report is a close match to that of the Baltimore classic, indicating a high degree of co-citation. The editor of Advances in Virus Research asked Temin and Baltimore to collaborate on a review of their work, which they did in 1971. The paper, which is Baltimore's fourth most-cited, accumulated 378 citations by the end of 1989. "Although the study of retroviruses and reverse transcriptase has moved rapidly, much of the basic information in this first review is still valid, and the review seems to be accepted as authoritative," Temin wrote in 1988 in his Citation Classic commentary (see Current Contents/Life Sciences, 31[51-52]:19, 19-26 Dec. 1988). Temin noted that recent references to the review "were in articles about human immunodeficiency virus, but others were about retroviruses, oncogenes, hepatitis B virus, and DNA polymerases in general," which illustrates the broad impact their work has had. Temin concluded: "There is, if anything, more interest in reverse transcriptase now than when it was first discovered and this review was written." Recently, Baltimore also has been writing about who should regulate the work and publication of scientists (see accompanying story). Despite the heavy administrative responsibilities of his new position, there can be little doubt, based on his output while at the Whitehead, that Baltimore will continue to publish a series of high-impact papers. David Pendlebury is an analyst in the Research Department at ISI in Philadelphia. He also edits ISI's monthly newsletter, Science Watch. Over the years, David Baltimore has produced more than his share of attention-getting papers. But he probably wishes that one on his bibliography would stop attracting so much interest, at least among nonscientists: "Altered repertoire of endogenous immunoglobulin gene expression in transgenic mice containing a rearranged mu heavy chain gene," published in Cell, 45:247-59, May 1986. This paper has been the focus of no fewer than four congressional hearings, two NIH inquiries, and numerous press stories - all concerning the authenticity of the research it reports. The three-year-old controversy stems from postdoc Margot O'Toole's inability to repeat experiments in Thereza Imanishi-Kari's laboratory at the Massachusetts Institute of Technology. O'Toole's questions on the validity of the Cell paper, which Imanishi-Kari, Baltimore, and four others published together, eventually found their way to the door of Rep. John Dingell (D-Mich.), chairman of the oversight subcommittee of the House Energy and Commerce committee. Two other papers among Baltimore's seven most-cited were published in 1970. Both papers - his fifth and sixth most-cited - were written with his wife, Alice S. Huang, who is affiliated with Children's Hospital in Boston and Harvard University. (Huang will be on leave in the coming year.) The fifth reviewed the mechanism of viral disease, and the sixth dealt with RNA polymerase in vesicular stomatitis virus. Baltimore's second most-cited paper appeared in 1975, and the third and seventh most-cited articles were published in 1980 and 1981, respectively. The second and third most-cited papers focus on leukemia viruses and oncogenesis, while the seventh is a minireview, written for Cell, on gene conversion, one of two ways that genes maintain their sequence homogeneity (the other is unequal crossing-over). Baltimore's research impact shows no signs of flagging. In the past year, three of his recent papers, published in 1988 and 1989, have made The Scientist's "Hot Papers" column. One, on homeobox proteins, appears in this issue (see page 17), and the two others, on an inhibitor of a transcription factor and a new DNA binding and dimerization motif, were listed in the Oct. 2, 1989, issue (page 15) and the May 28, 1990, issue (page 20). CITATIONS TO CELL PAPER From: Year JournalsNews Stories 1986 3 0 1987 14 0 1988 12 14 1989 11 12 Total: 40 Total: 26 Dingell's staff and the U.S. Secret Service have gone to extraordinary lengths to determine whether the research reported is the result of fraud. Baltimore, although not directly charged with misconduct by Dingell, has aggressively defended his co-author Imanishi-Kari and has taken the opportunity to argue forcefully that scientists - and not politicians - should be charged with the oversight responsiblity for scientific research. While Dingell's staff has carried on with its investigations of the Cell paper, researchers around the world have continued to cite the science it contains. The Scientist examined the Institute for Scientific Information's Science Citation Index and identified papers that cited the Cell paper between 1986 and the end of 1989. The chart above divides the citations by year and by the type of citing article. Although the paper is plainly not one of Baltimore's most cited, neither has it been ignored by the scientific community. The paper was ignored by the media until 1988, when the controversy broke. ("News Stories" represents articles in the news sections of Science, Nature, New Scientist, The Scientist, and others.) --D.P.

Research: A Citation Profile Of David Baltimore, Rockefeller University's New President

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