SUMMARYThe virulence offaecal and urinary Escherichia coli strains was studied in relation to serotype, haemolysin production and haemagglutination pattern. By means of an experimental mouse model E. coli strains can be divided into avirulent (I), mouse nephropathogenic (II), and generally virulent (III) strains. Virulent group II and group III strains were more often haemolytic and haemagglutinating than avirulent group I strains. Presence of K antigen could not be associated with virulence. Discriminant analysis for qualitative variables revealed that no combination of the investigated properties contributed more to a strain's virulence level than did one single property. It is concluded that other virulence factors, apart from haemolysin production in group II strains and haemagglutinins in group III strains, must be involved in the determination of a strain's virulence level.All 02, 06 and 018 ac strains tested were virulent, and by far the most 075 strains were avirulent, whereas other 0 groups were more variable with regard to virulence. Pyelonephritis strains were more often mannose-resistant haemagglutinating than faecal and other urinary isolates, indicating that mannoseresistant adhesins may be important in the pathogenesis of pyelonephritis.
The reproducibility of ejection fraction measurements has been studied using gated equilibrium blood pool scintigraphy. The use of appropriate statistical tests is proposed and commented upon. The intra-observer variability for our group of patients has a standard deviation of 6.4%, the interobserver variability of 3.2% and sequential studies done on the same and different days give standard deviations (due to "time" alone) of 1.0% and 1.9%, respectively. Different factors and sources involved in variability are mentioned. Variability values reported in the literature are discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.