Defence mechanisms, specific

Non-specific defence mechanisms 4.6.2 Suppressor cells (Ts cells)... 

Complement comprises a group of heat-labile serum proteins which, when activated, are associated with the destruction of bacteria in the body in a variety of ways. It is present in low concentrations in serum but, as its action is linked intimately with a second (specific) set of defence mechanisms, its composition and role will be dealt with later in the chapter. 

Specific defence mechanisms (adaptive immune system)... 

It has a particular function when ingested, e.g. enhancement of a defence mechanism, prevention or amelioration of a specific disease, recovery from a specific disease, or slowing of the ageing process. 

We do not dream because our unconscious wishes or drives would, if undisguised, wake us up. We dream because our brains are activated during sleep, and we do so even if our primitive drives are turned on by that activation. In fact, such drives are not concealed. Rather, they are revealed in dreams. It is the specific neurophysiological details of that activation process, not psychological defence mechanisms, that determine the distinctive nature of dream consciousness. 

Kelly PM, Cory IS (1987) Operculum closing as a defense against predatory leeches in four British freshwater prosobranch snails. Hydrobiologia 144 121-124 Rundle SD, Bronmark C (2001) Inter- and intra specific trait compensation of defence mechanisms in freshwater snails. Proc Biol Sci 268 1463-1468... 

The benzylisoquinolines are formed from two molecules of fhe aromafic amino acid, tyrosine. In the past ten years, this pathway has been probed at the enzyme and gene level. The recent linking of the phloem-specific expression of tyrosine/Dopa decarboxylase (TYDC) genes with the bios)mthesis of the isoquinoline alkaloids in the opium poppy, Papaver somniferum (Facchini and De Luca, 1994, 1995, 2008 Liscombe and Facchini, 2008), and the association with alkaloid accumulation as part of the plant defence mechanism (Wink, 1993 Facchini et al, 1996) are of particular interest in furthering our knowledge of the location of alkaloid biosynthesis. 

Liew, F.Y. and Cox, F.E. (1991). Non-specific defence mechanism the role of nitric oxide. Immunol. Today 12, A17-A21. 

The functions of the classical complement pathway are similar to those described for the alternative pathway, i.e. opsonization, leucocyte activation and membrane lysis of target cells. The classical pathway can additionally lead to complement protein deposition upon insoluble anti-body-antigen immune complexes circulating within blood, and in doing so promote the clearance of such potentially harmful complexes by Kupffer cells of the liver. The presence of two complement pathways provides for rapid (alternative) and specific (classical) activation of a key defence mechanism, and offers greater protection... 

There is considerable body of (indirect) evidence which makes oxidative stress one of the best accepted hypothesis for explaining the cause of Parkinson s disease. For example, the Fe(II)/Fe(III) ratio in the substantia nigra is shifted from 2 1 in the normal brain to 1 2 in Parkinsonian brain.131,132 In the Parkinsonian brain several enzymes which constitute the antioxidative defence mechanisms (glutathione peroxidase, catalase) have a decreased activity, while the activity of superoxide dismutase is increased, relative to the normal brain.133 Furthermore, specific products of radical damage, such as lipid hydroperoxides, were detected at a 10-fold increased level in the Parkinsonian brain.134... 

Cells are equipped with a large number of defence mechanisms, or stress response pathways, to protect themselves and their surrounding tissue from injury. The majority of these defence mechanisms are turned on to redress a specific homeostatic imbalance and are turned off again when homeostasis has been restored. Such pathways include the p53 stress response, which senses amongst other things DNA damage, Nrf2 oxidative stress response, HIF-1 alpha hypoxia stress response, unfolded protein response, and inflammatory stress responses [34], In this chapter we aim to demonstrate how some of these pathways have contributed to the identification of excellent mechanistic biomarkers. In Chap. 19 we describe these pathways in much more detail. 

Dalmo, R.A., K. Ingebrigste and J. Bogwald. Non-specific defence mechanisms in fish, with particular reference to the reticuloendothelial system (RES). J. Fish Dis. 20 241 -273, 1997. 

Toxicity is not a specific property of any particular contaminant, but the result of interactions between the substance and the species exposed to it. The toxic potential of chemicals to affect cells, organs and organisms adversely is determined by the affinity for and the effectivity of the interactions between the chemical agent and the biological components (e.g. the receptors) in the organism, as well as the dose or concentration of the contaminant. The potential toxic effects may partly be compensated by the defence mechanisms of the affected biota (repair, regeneration and regulation at different levels of the... 

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