Animal studies environmental stress

Numerous physiological and environmental factors such as age, stress, nutritional deficiency, and infections may affect the immune system (Sullivan, 1989). Thus, adverse findings in animal studies may reflect these indirect immunotoxic effects rather than the direct immunotoxic potential of a chemical or drug. Indirect immunotoxic effects may be assessed through histopathologic evaluations of endocrine organs such as the adrenals and pituitary. 

Safety assessment scientists and technicians and even QA personnel sometimes overlook the importance of environmental control equipment to valid study results. Animals stressed by extremes of temperature or humidity may 5ueld spurious data reproductive toxicology studies may be compromised by malfunctioning timers for the control of light/ dark cycles inadequate air filtration may expose experimental animals to environmental contaminants that confound experimental results. 

Sekiguchi, K., Yamamichi, Y., Costlow, J.D. Horseshoe crab developmental studies I. Normal embryonic development of Limulus polyphemus compared with Tachypleus tridentatus. In Bonaventura, J., Bonaventura, C., Tesh, S. (eds), Physiology and Biology of Horseshoe Crabs Studies on Normal and Environmentally Stressed Animals. Alan R. Liss, NY (1982), pp. 53-73. 

One important aspect is solution condition. In most laboratory experiments dilute protein solutions are used in dilute salt or cosolvent conditions. These conditions are widely different from those found in the living cell. In the cell molecular crowding from the presence of macromolecules may have a profound influence on protein-protein interactions [99]. In addition low molar mass compounds may accumulate under certain conditions in the cells of certain plants, animals and microorganisms to cope with environmental stresses. The presence of these molecules may have important contributions to the dynamics, the stability and the interactions of proteins [100]. While the effect of these molecules has been studied widely on the temperature stability of proteins, their detailed study on the effect of the pressure stability is just at a beginning [101]. 

Brouwer M, Bonaventura C, Bonaventura J (1982) Chloride and pH dependence of cooperative interactions in Limulus polyphemus hemocyanin. In Bonaventura J, Bonaventura C, Tesh S (eds) Physiology and biology of horseshoe crabs studies on normal and environmentally stressed animals. Alan R Liss, New York, p 231... 

Epidemiologic, experimental, and in vitro mechanistic data indicate that lead exposure elevates blood pressure in susceptible individuals. In populations with environmental or occupational lead exposure, blood lead concentration is linked with increases in systolic and diastolic blood pressure. Studies of middle-aged and elderly men and women have identified relatively low levels of lead exposure sustained by the general population to be an independent risk factor for hypertension. In addition, epidemiologic studies suggest that low to moderate levels of lead exposure are risk factors for increased cardiovascular mortality. Lead can also elevate blood pressure in experimental animals. The pressor effect of lead may be mediated by an interaction with calcium mediated contraction of vascular smooth muscle, as well as generation of oxidative stress and an associated interference in nitric oxide signaling pathways. 

HSPs as cellular markers of stress HSPs are involved in various aspects of cellular function and a lot is being learnt about its role in normal and pathological states. Recent studies from lower animals, especially fish, have revealed the potential use of induced fish HSPs as a biomarker of exposure to environmental stressors. Industrial effluents, polycyclic aromatic hydrocarbons, metals such as copper, zinc, mercury, pesticides, etc. have shown to induce HSP in fish. Further, the HSP response may vary with the stressor, tissue, species of fish, and the family of HSP studied. Hence it appears that a more extensive and probably a high-throughput profiling (using genomic and pro-teomic) approaches may be necessary to identify patterns of HSP modulation by various stressors. 

Initial studies of proteome responses to environmental chemicals in soil-dwelling animals or plants are currently under way. Kuperman et al. (2004) have used the approach to identify differentially expressed proteins in earthworms exposed to chemical warfare agents. Toxicological studies also have been undertaken. Vido et al. (2001) analysed yeast cells exposed to an acute cadmium stress 54 proteins were induced and 43 repressed. Finally, Bradley (2000) used two-... 

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