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Parasites are ubiquitous in nature and can be costly to animal fitness, so hosts have evolved behavioural counter-strategies to mitigate infection risk. We investigated feeding-related infection-avoidance strategies in Japanese macaques via field-experimentation and observation. We first examined risk sensitivity during foraging tasks involving faecally contaminated or debris-covered food items, and then investigated individual tendencies to manipulate food items during natural foraging bouts. We concurrently monitored geohelminth infection in all subjects. We ran a principal component analysis on the observational/experimental data to generate a hygienic index across individuals and found that hygienic tendencies towards faeces avoidance and food manipulation correlated negatively with geohelminth infection. Females scored higher in hygienic tendencies than males, which might contribute to the common vertebrate pattern of male-biased infection. The behavioural tendencies observed may reflect a general form of hygiene, providing a mechanism of behavioural immunity against parasites with implications for the evolution and diversification of health maintenance strategies in humans. 相似文献
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Cecile Gache Yolande Berthois Pierre-Marie Martin Simone Saez 《In vitro cellular & developmental biology. Animal》1998,34(4):347-351
Summary In the mammary gland, mesenchymal-epithelial interactions are of paramount importance during normal and tumoral developments.
We have studied the paracrine growth regulation of a variety of breast epithelial cells in coculture with normal or pathological
breast fibroblasts. Two models of coculture were used in which the two cell types were seeded and grown, either together in
microchamber slides or separated by a microporous membrane. Under these two conditions, all fibroblasts were shown to stimulate
the proliferation of the hormono-responsive breast carcinoma MCF-7 cell line, suggesting that cell contacts were not indispensable
for the paracrine stimulation of MCF-7 cell growth by fibroblasts. Moreover, in the Transwell coculture system, the proliferation
of a variety of other breast carcinoma cells (MDA-MB231, T47D, and BT-20) was also stimulated by fibroblasts. However, the
amplitude of the proliferative response seemed to be dependent on the carcinoma cell line considered. Moreover, the proliferative
response of normal mammary epithelial cells to the presence of fibroblasts was shown to be significantly higher than the tumor
cell response. The nature of the tissue of fibroblast origin, normal or pathological, did not influence the growth response
of the epithelial cells. In this study, we thus demonstrate that fibroblasts are able to stimulate the proliferation of normal
and carcinoma cells through paracrine exchange mechanisms. We also conclude that the target epithelial cell phenotype will
essentially determine the extent of the proliferative response. 相似文献
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Submaximal and/or maximal exercise was carried out by 357 women without a history of cardiovascular disease, using a bicycle ergometer and/or treadmill while monitored by a bipolar ECG lead CM5. In 40- to 60-year-old women the incidence of an ischemic ECG pattern during or after exercise ranged from 20 to 50%. Because clinical coronary disease can be expected in less than 10% of normal women followed for 16 years, most of these ECG changes were not considered to be due to occult coronary disease. At the present time exercise ECG changes in women cannot be used with any reliability as an aid in the diagnosis of chest pain or in screening normal female populations for coronary heart disease. 相似文献
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