Tobacco and the risk of acute leukaemia in adults

Self-reported smoking histories were collected during face-to-face interviews with 807 patients with acute leukaemia and 1593 age- and sex-matched controls. Individuals who had smoked regularly at some time during their lives were more likely to develop acute leukaemia than those who had never smoked (odds ratio (OR) = 1.2, 95% confidence interval (CI) 1.0–1.4). The association was strongest for current smokers, defined here as smoking 2 years before diagnosis (OR = 1.4, 95% CI 1.1–1.7). With respect to the numbers of years smoked, risk estimates were raised in all groups except those who had smoked for fewer than 10 years. Similarly, the odds ratio decreased as the number of years ‘stopped smoking’ increased, falling to one amongst those who had given up smoking for more than 10 years. No significant linear trends were found, however, with either the numbers of years smoked or the numbers of years stopped smoking, and no significant differences were found between AML and ALL. © 1999 Cancer Research Campaig

Gen-morph species concept-A new and integrative species concept for outbreeding organisms

The present article briefly reviewed the prevailing species concepts, especially biological, genetic, evolutionary, phylogenetic, ecological, and several taxonomic species concepts. The former five reflect the properties of species from diverse aspects and in different degrees, while taxonomic species concepts all contain more or less subjective elements, except for Hedberg's taxonomic method (not species concept). So far, there is no species concept that is both theoretically rational and practically operable. The present article outlined recent studies on the genusPaeoniaL. (Paeoniaceae) in biology, particularly in morphology, biogeography, molecular phylogeny, and reproductive behavior, which provided insight into the relationship between variation of morphological characteristics and phylogeny. Taking the study onPaeoniaL. as a case, referring to studies on some other plant groups, and incorporating the merits of the prevailing species concepts into our consideration, gen-morph species concept is proposed here formally as new for outbreeding organisms. The new species concept has three special features: (i) a bridge linking morphological aspect with genetic and other aspects of species; (ii) proposal of a concrete morphological criterion for species definition, and (iii) considering quantitative and qualitative characteristics as equally valuable for species definition and introducing statistics into the concept to handle such characteristics. Therefore, the gen-morph species concept is an integrative species concept, both theoretically objective and practically operable