In response to trauma

There Is a Loss of Body Protein in Response to Trauma Infection... 

Figure 18.5 A summary of the biochemical, physiological and immunological changes brought about by cytokines in response to trauma. Cytokines can be produced in trauma from macrophages, lymphocytes, endothelial cells in the tissue that is damaged, and also by Kupffer cells if the liver is damaged. IL-1, IL-6 - interleukins 1 and 6 TNF - tumour necrosis factor, IFN - interferon.

ECMs contain a variety of cell types (see Table 1.2) such as fibroblasts in the skin, chondrocytes in cartilage, and osteoblasts in bone. The role of these cells is to synthesize and deposit the ECM surrounding the cell and to change the amount and location of the ECM in response to trauma and changes in external loading. For instance, collagen synthesis in these cells is typically up-regulated by the application tensile forces and is down-... 

Cortisol is a stress hormone released in response to trauma—physical and emotional— that leads to several physiologic changes aimed at reducing the stress associated with this trauma. This process is helpful to the body because the activity of cortisol can limit the harmful effects of stress. However, if too much cortisol is secreted (hypercortisolism) symptoms of Cushing syndrome may appear. 

The release of arachidonic acid is stimulated in response to trauma (tissue damage). It is believed that the anti-inflammatory effects of adrenocortical steroids derive from their ability to suppress the enzymes that cause the release of arachidonic acid, thereby preventing the biosynthesis of prostaglandins. 

In response to trauma or infection (section 9.1.2.2) or if the intake of protein is inadequate to meet requirements, there is net a loss of nitrogen from the body — the output is greater than the intake. This is negative nitrogen balance intake < output and there is a loss of body protein. 

This protein loss is mediated by the hormone cortisol, which is secreted in response to stress, and the cytokines that are secreted in response to trauma four mechanisms are involved ... 

A problem arises in the interpretation of leukocyte ascorbate concentrations because of the different capacity of different classes of leukocytes to accumulate the vitamin. Granulocytes are saturated at a concentration of about 530 pmol/10 cells, while mononuclear leukocytes can accumulate 2.5 times more ascorbate. A considerable mythology has developed to the effect that vitamin C requirements are increased in response to infection, inflammation, and trauma, based on reduced leukocyte concentrations of ascorbate in these conditions. However, the fall in leukocyte ascorbate can be accounted for by an increase in the proportion of granulocytes in response to trauma and infection (and hence a fall in the proportion of mononuclear leukocytes). Total leukocyte ascorbate is not a useful index of vitamin C status without a differential white cell count. 

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