Karen A. Bowman

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFurther purification and characterization of scrapie prionsStanley B. Prusiner, David C. Bolton, Darlene F. Groth, Karen A. Bowman, S. Patricia Cochran, and Michael P. McKinleyCite this: Biochemistry 1982, 21, 26, 6942–6950Publication Date (Print):December 1, 1982Publication History Published online1 May 2002Published inissue 1 December 1982https://pubs.acs.org/doi/10.1021/bi00269a050https://doi.org/10.1021/bi00269a050research-articleACS PublicationsRequest reuse permissionsArticle Views1025Altmetric-Citations338LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Abstract The titer of the scrapie agent was determined by measurements of time intervals from inoculation to onset of illness and from inoculation to death. Both intervals were found to be inversely proportional to the size of the dose injected intracerebrally into random‐bred weanling Syrian hamsters. The logarithms of the time intervals minus a time factor were linear functions of the logarithm of the inoculum size. The time factors were determined by regression analysis in order to maximize these linear relationships. An equation relating the titer of the inoculum to the dilution of the sample and the length of the time intervals was developed. This equation facilitates the use of a computerized data base. Validation of these relationships was provided by comparing samples for which the agent was measured both by end‐point titration and by time interval assay. Agreement between the two methods was generally within ±0.5 log 10 median infective dose units. No differences between the molecular properties of the agents from hamster and murine sources were observed using primarily the incubation time interval method with the former and end‐point titration with the latter. The advantages of this new approach based on time interval measurements are considerable with respect to time and resources.