Furthermore, the persistence of exposure to tobacco among ex-drinkers may play an important role in limiting the benefits of drinking cessation.
The mechanism by which membrane-based formulations act could be similar to that of oil-based adjuvants [ 12], forming a depot that slowly releases the antigen prolonging its persistence and exposure time to immunocompetent cells.
The persistence of exposure to each occupational activity (heavy lifting or stair climbing) was assessed by devising the following score for each activity: 0 - no exposure at either time point, 1 - exposure at either, but not both time points and 2 - exposure at both time points.
Five mouse organs and four mouse brain regions were examined and compared in very young (7 and 14 days old), adolescent (24 days old), young adult (30 days old) and sexually mature adult (45 days old) male and female mice for the incidence of γ-H2AX focus induction and persistence after exposure to 1 Gy of X rays.
Oral administration of 2.27 g OVA the day after birth (Group A) or 0.23 g OVA daily for 3 days after birth (Group B) did not promote significant induction of serum anti-OVA IgG titres which suggest that whether lambs respond to oral antigen with immunity or not is dependent upon dose or persistence of exposure.
The prevalence of asthma appears to be increasing in urban and rural populations in developing countries [ 6, 7], and increasing urbanization and the acquisition of modern lifestyle, coupled perhaps with environmental triggers for non-atopic symptoms and or the persistence of exposures that attenuate atopy [ 8, 9], has been the most cited factors to explain these epidemiological trends [ 10, 11].
As the timing of the next pandemic influenza outbreak is unknown, the memory response may be more important than persistence, as subsequent exposure to the pandemic vaccine or wild-type virus could trigger a full immunologic response.
Surprisingly, the growth rate of individual cells does not correlate with their fate (death or persistence) under antibiotic exposure.
In contrast to beta-lactam induced persistence, IFN-Ƴ exposure in vitro, makes chlamydia more resistant to doxycycline, but still susceptible to azithromycin [ 44].
Studies of environment, wildlife, and humans suggest widespread presence and exposure, persistence in the environment, and bioaccumulation (Giesy and Kannan 2001; Kannan et al. 2004).
