HEALTH VALUE IN FOOD SAFETY SURVEILLANCE INITIATIVES

Recognizing the increasing concern about the potential health effects of genetically modified foods, this research provides a framework for economic value of monitoring genetically modified food for their potential long-term human health effects. This is with the view of helping policy makers improve resource allocation decisions in the face of competing public health initiatives. Using a hypothetical population exposed to a hypothetical product, we estimate the health value associated with a post-market surveillance initiative. The analysis indicate that the principal challenge confronting decision makers in the implementation of post-market surveillance initiatives is prioritising products for monitoring given the uncertainty associated with outcomes and effects.Food Consumption/Nutrition/Food Safety,

Blood polymorphonuclear leukocyte chemotaxis during experimental escherichia-coli bovine mastitis.

The relationship between the severity of experimental Escherichia coli mastitis and the chemotactic response of blood polymorphonuclear leukocytes was investigated before and during mastitis. Experimental E. coli mastitis was induced in 10 healthy cows by inoculation of the rear right quarters with 10(3) cfu of E. coli. Cows were classified into two groups based on the severity of the mastitis. Bacterial growth in the inoculated quarter was used as parameter that indicated severity. Before and during experimental mastitis, the chemotactic response and the number of circulating polymorphonuclear leukocytes were greater for the moderately diseased cows than for the severely diseased cows. During the first 24 h of the experimental mastitis, the chemotactic response of polymorphonuclear leukocytes decreased in both groups. Recovery of the chemotactic response of white blood cells was more rapid in moderately diseased cows than in severely diseased cows. Possibly, the larger proportion of band neutrophils (the less chemotactically active band neutrophils) partially accounts for the lower chemotactic response of the circulating polymorphonuclear leukocytes during experimental mastitis in the severely diseased cows

Pro-inflammatory role of monocyte-derived CX3CR1int macrophages in Helicobacter hepaticus-induced colitis

Cells of the monocyte-macrophage lineage play important roles in the pathogenesis of inflammatory bowel diseases, but they are also present in the normal healthy intestine, where they are critical for maintaining homeostasis. It has been unclear whether the pro-inflammatory roles of intestinal macrophages reflect altered behaviour of the existing resident cells, or if they involve recruitment of a distinct cell type. Here we have explored these ideas using the model of colitis induced by Helicobacter hepaticus (Hh) in the context of neutralisation or deletion of interleukin 10 (IL-10). Granulocytes and monocytes made up most of the inflammatory myeloid infiltrates found in the colon of Hh-infected colitic mice, rising to a peak within 2 weeks of Hh inoculation, but taking several months to resolve completely. The inflammatory response was dependent on the combined presence of Hh and absence of IL-10, and was accompanied by increased production of inflammatory mediators such as IL-1β, TNFα, IL-6 and IL-23p19 by infiltrating myeloid cells, mostly relatively immature cells of the macrophage lineage that express intermediate levels of CX3CR1. In contrast, the population of mature CX3CR1hi macrophages did not expand as markedly during colitis, and these cells made little contribution to inflammatory mediator production. Taking into account their numerical dominance in the myeloid compartment, we conclude that newly recruited monocytes are the main source of pro-inflammatory mediators in colitis induced in the absence of IL-10 signalling, and that altered behaviour of mature macrophages is not a major component of this pathology

Expression and characterisation of αvβ5 integrin on intestinal macrophages

Macrophages play a crucial role in maintaining homeostasis in the intestine, but the underlying mechanisms have not yet been elucidated fully. Here we show for the first time that mature intestinal macrophages in mouse colon and small intestine express high levels of αvβ5 integrin, which acts as a receptor for the uptake of apoptotic cells and can activate molecules involved in several aspects of tissue homeostasis such as angiogenesis and remodelling of the extracellular matrix. αvβ5 is not expressed by other immune cells in the intestine, is already present on intestinal macrophages soon after birth, and its expression is not dependent on the microbiota. In adults, αvβ5 induces the differentiation of monocytes in response to the local environment and it confers intestinal macrophages with the ability to promote engulfment of apoptotic cells via engagement of the bridging molecule milk fat globule EGF‐like molecule 8. In the absence of αvβ5, there are fewer monocytes in the mucosa and mature intestinal macrophages have decreased expression of metalloproteases and interleukin 10. Mice lacking αvβ5 on haematopoietic cells show increased susceptibility to chemical colitis and we conclude that αvβ5 contributes to the tissue repair by regulating the homeostatic properties of intestinal macrophages