A Role for the Vacuolating Cytotoxin, VacA, in Colonization and Helicobacter pylori-Induced Metaplasia in the Stomach

Carriage of Helicobacter pylori strains producing more active (s1/i1) forms of VacA is strongly associated with gas-tric adenocarcinoma. To our knowledge, we are the first to determine effects of different polymorphic forms of VacA on inflammation and metaplasia in the mouse stomach. Bacteria producing the less active s2/i2 form of VacA colonized mice more efficiently than mutants null for VacA or producing more active forms of it, providing the first evidence of a positive role for the minimally active s2/i2 toxin. Strains producing more active toxin forms induced more severe and extensive metaplasia and in flammation in the mouse stomach than strains producing weakly active (s2/i2) toxin. We also examined the association in humans, controlling for cag PAI status. In human gastric biopsy specimens, the vacA i1 allele was strongly associated with precancerous intestinal metaplasia, with almost complete absence of intestinal metaplasia in subjects infected with i2-type strains, even in a vacA s1, cagA+ background

Heterogeneous Beliefs and Asset Price Dynamics: A Survey of Recent Evidence

This paper reviews the empirical literature on heterogeneous beliefs and asset price dynamics that challenges the traditional rational agent framework. Emphasis is given to the validation and estimation of (dynamic) heterogeneous agent models that have their roots in the agent-based literature. Heterogeneous agent models per- form well in describing, explaining, and often forecasting asset markets dynamics, such as equities, foreign exchange, credit, housing, derivatives, and commodities. Our survey suggests that heterogeneous agent models have the ability to produce important stylised facts observed in nancial time series and to replicate important episodes of nancial turmoil.publishedVersio

Evidence for an own-age bias in age estimation from voices in older persons

peer reviewedPrevious studies have investigated the effect of ageing on age estimation from faces as well as the occur- rence of an own-age bias in such age estimation from faces. To the best of our knowledge, the occurrence of an own age effect on age estimation from voices has never been examined earlier using an experimental design in which the age of participants (young vs. old) and the age of voice stimuli (young vs. old) were crossed. Results revealed an own-age bias in older adults only. In comparison with younger adults, older participants showed age estimation abilities that are preserved for voices from their own age group and impaired for younger voices. This own age bias was absent in younger participants