Tracking Latent Domain Knowledge - Mapping Scientific Frontiers: The Quest for Knowledge Visualization - page 248

Fig. 7.15 A year-by-year animation shows the growing impact of research in the connections
between BSE and vCJD. Top-left : 1991-1993; Top-right : 1994-1996; Bottom-left : 1997-1999;
Bottom-right : 2000-2001

idea seemed to threaten the very foundations of molecular biology, which held that
nucleic acids were the only way to transmit information from one generation to the
next.
Fifteen years later, in 1982, Prusiner followed up this idea of self-replication
proposed in the 1960s and described the “proteinaceous infectious particles” as the
cause of scrapie in sheep and hamsters. He suggested that scrapie and a collection of
other wasting brain diseases, some inherited, some infectious, and some sporadic,
were all due to a common process: a misfolded protein that propagates and kills
brain cells.
Prusiner and his colleagues reported in Science in 1982 that they had found an
unusual protein in the brains of scrapie-infected hamsters that did not seem to be
present in healthy animals. Their article, entitled “Novel proteinaceous infectious
particles cause scrapie,” has been cited 941 times by March 2001. A year later,
they identified the protein and called it prion protein (PrP). Prusiner led a series of
experiments, demonstrating that PrP actually is present in healthy animals, but in a
different form from the one found in diseased brains. The studies also showed that
mice lacking PrP are resistant to prion diseases. Taken together, the results have
convinced many scientists that the protein is indeed the agent behind CJD, scrapie,
mad cow disease, and others. Figure 7.15 shows four frames from an animation
sequence of the year-by-year citation growth. Figure 7.16 shows the following four
most cited articles over the period of 1995-2000.

• Will, R. G., Ironside, J. W., Zeidler, M., Cousens, S. N., Estibeiro, K.,

Alperovitch, A., Poser, S., Pocchiari, M., Hofman, A., & Smith, P. G. (1996).
A new variant of Creutzfeldt-Jakob disease in the UK. Lancet, 347 , 921-925.