Celina Gonçalves

Adherence of Giardia lamblia Trophozoites to Int-407 Human Intestinal Cells

ABSTRACT Attachment of Giardia lamblia trophozoites to enterocytes is essential for colonization of the small intestine and is considered a prerequisite for parasite-induced enterocyte dysfunction and clinical disease. In this work, coincubation of Giardiawith Int-407 cells, was used as an in vitro model to study the role of cytoskeleton and surface lectins involved in the attachment of the parasite. This interaction was also studied by scanning and transmission electron microscopy. Adherence was dependent on temperature and was maximal at 37°C. It was reduced by 2.5 mM colchicine (57%), mebendazole (10 μg/ml) (59%), 100 mM glucose (26%), 100 mM mannose (22%), 40 mM mannose-6-phosphate (18%), and concanavalin A (100 μg/ml) (21%). No significant modification was observed when Giardia was pretreated with cytochalasins B and D and with EDTA. Giardia attachment was also diminished by preincubating Int-407 cells with cytochalasin B and D (5 μg/ml) (16%) and by glutaraldehyde fixation of intestinal cells and ofG. lamblia trophozoites (72 and 100%, respectively). Ultrastructural studies showed that Giardia attaches to the Int-407 monolayer predominantly by its ventral surface. Int-407 cells contact trophozoites with elongated microvilli, and both trophozoite imprints and interactions of Giardia flagella with intestinal cells were also observed. Transmission electron microscopy showed that Giardia lateral crest and ventrolateral flange were important structures in the adherence process. Our results suggest a combination of mechanical and hydrodynamic forces in trophozoite attachment; surface lectins also seem to mediate binding and may be involved in specific recognition of host cells.

Consumer Behaviour in Fitness Club: Study of the Weekly Frequency of Use, Expectations, Satisfaction and Retention

This study aims to understand the relationship between the weekly frequency of use, expectations, satisfaction and retention of members in a fitness Clubs. In this market it is indispensable to understand the characteristics of faithful members, in order to act appropriately with each segment. Accordingly, the weekly frequency, which a member goes to the gym, their expectations, satisfaction and retention are key variables to understand them. Data was collected with a sample of 146 members. The instrument was constituted by the sample characterization and questions to understand the consumer behaviour in fitness (weekly frequency of use, expectations, satisfaction and retention behaviours). The statistical analysis consisted on descriptive and inferential analyses, using SPSS software. In this study the weekly frequency did not show the explanatory capacity to predict the satisfaction and retention. The relationship between expectations with satisfaction (73%) and retention (64%) was statistically significant. Finally, the relationship between satisfaction and retention (63%) was positive and significant. The results indicated that fitness club managers must act to keep those who are less likely to remain, who aren’t the ones who go less times a week to the club, but those who have a lower satisfaction and, consequently, lower retention.