Lifetime physical activity and risk of breast cancer in pre-and post-menopausal women

© 2015 Springer Science+Business Media New York To investigate the association between different types of physical activity (PA) and breast cancer. A case–control study of breast cancer was conducted in Western Australia from 2009 to 2011, in which 1205 women with breast cancer and 1789 frequency age-matched breast cancer-free control women were recruited. A self-administered questionnaire was used to collect information about lifetime and age-period recreational, household, occupational and transport physical activities. Detailed questions about demographic characteristics, and relevant reproductive, medical and lifestyle factors were also included. Logistic regression and restrictive cubic spline analyses were applied to investigate the association and dose–response relationship between PA and breast cancer risk. Subgroup analysis was performed regarding menopausal status. We found non-linear dose–response associations between PA and risk of breast cancer. Overall, 95–130 MET-hours/week of total lifetime PA was associated with the lowest breast cancer risk. The effects were stronger among post-menopausal women. We also found that the medium amounts of recreational PA (up to 21 MET-hours/week) were associated with lower breast cancer risk among post-menopausal women. Further analysis on the intensity of recreational PA demonstrated different dose–response associations between moderate- and vigorous-intensity recreational PA and breast cancer risk. We found that PA was associated with a reduced risk of breast cancer among post-menopausal women, but not in a linear fashion. Recreational PA of different intensities may have different dose–response associations with risk of breast cancer

RORγt + Treg to Th17 ratios correlate with susceptibility to Giardia infection

Funder: Fundacion Alfonso Martin EscuderoFunder: RCUK | Biotechnology and Biological Sciences Research Council (BBSRC); doi: https://doi.org/10.13039/501100000268Funder: Isaac Newton Trust; doi: https://doi.org/10.13039/501100004815Abstract: Infections with Giardia are among the most common causes of food and water-borne diarrheal disease worldwide. Here, we investigated Th17, Treg and IgA responses, and alterations in gut microbiota in two mouse lines with varying susceptibility to Giardia muris infection. Infected BALB/c mice shed significantly more cysts compared with C57BL/6 mice. Impaired control of infection in BALB/c mice was associated with lower Th17 activity and lower IgA levels compared with C57BL/6 mice. The limited metabolic activity, proliferation and cytokine production of Th17 cells in BALB/c mice was associated with higher proportions of intestinal Foxp3+RORγt+ regulatory T cells and BALB/c mice developed increased RORγt+ Treg:Th17 ratios in response to G. muris infection. Furthermore, G. muris colonization led to a significantly reduced evenness in the gut microbial communities of BALB/c mice. Our data indicate that differential susceptibility to Giardia infections may be related to RORγt+ Treg controlling Th17 activity and that changes in the microbiota composition upon Giardia infection partially depend on the host background

In vitro synthesized immunoglobulin A from nu/+ and reconstituted nu/nu mice against a dominant surface antigen ofGiardia lamblia

Nu/+ mice (ZU.ICR-strain) experimentally infected with Giardia lamblia (clone GS/M-83-H7) cleared the infection by day 45 postinfection (p.i.). Athymic nu/nu mice were reconstituted with immune Peyer's patch lymphocytes obtained from self-healed nu/+ littermates and thus acquired the potential to decrease their intestinal parasite mass. Intestinal B-cells from self-healed nu/+ mice as well as from immune-reconstituted athymic nude mice synthesized in vitro parasite-specific immunoglobulin A (IgA). This IgA was subsequently analyzed by immunoblotting, showing a predominant reaction with the major surface antigen (a 72,000-Da polypeptide) characterizing the Giardia clone in question. The hypothesis on the causative role of intestinal IgA and immune lymphocytes in the control of G. lamblia infection thus deserves further attention