This work is a qualitative study of an organism''s physiological adaptative response to stress. The experimental data were selected from a previous study leading to the conclusion that stress may be considered as a topological retraction within a vital space that must be more precisely defined. The experimental methodology uses rat poisoning by neurotoxins. The control parameter is the intensity of the toxic doses. Measured parameters are the animals'' survival rate and the kinetics of cerebral acetylcholinesterase activity. The results, when (...) expressed as a function of the inverted doses, show a characteristic evolution. The pattern of the curve closely resembles a vortex profile. This analogy is studied more extensively in both the physical and biological domains. These findings help to clarify the concept of biological stress which presents the same vectorial properties as hydrodynamic vorticity. In particular, the dissipation of stress and the dissipation of vorticity seem to obey the same laws. This observation is valid for both diffusion and convection processes. The decompensation phase of stress could be compared with the instability and turbulence in flows.Our approach in this paper is mainly to establish a general and phenomenological description of the stress response fitting experimental observations. (shrink)

In tracing the survival reaction of an organism, following a vital stress, we have proceeded from the breakdown of a cerebral enzyme as a function of the constraint, to its initial and spontaneous recovery. We have so observed a partial enzymatic recovery, the velocity of which being variable with respect to the constraint intensity. This velocity is expressed asdq/dt, that is, the quantity of enzymedq recovered per unit of timedt. In this paper, the basic idea is to consider the inverse (...) parameterdt/dq, that is, the timedt needed by the organism to recover a given quantity of enzymedq. The integration of this parameter over the constraint accumulated by the stressed organism allows us to determine a timeT which appears to be variable when observed by a distant observer.The properties of this timeT are discussed with the help of an analogical approach based on hydrodynamical and cosmological models. (shrink)

This work presents an hydrodynamical model of heat stroke, which is a physiopathological state of stress, due to an exposure of animals to an ambient temperature of approximatively 40°C during two hours. The evolution of body temperature during this stress process is characterised by three phases. A first phase of increase is followed by a plateau which occurs before a second phase of increase which can be lethal. The model is based on the analogy of a boat progressively caught in (...) a whirlpool. The evolution of the degree of freedom lost by the boat is mathematically analysed and this study leads to the same three phases. The theoretical curves calculated during this study are well in agreement with the experimental curves obtained with animals. This analogy is compared to a previous one which has been made during another experiment with animals constrained by chemical intoxications. It seems that stress can be considered as a vital vorticity and that hydrodynamic models are powerful tools in understanding this physiopathological state. (shrink)