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Computerised experimentation in biology
LETTER TO THE EDITOR
COMPUTERISED EXPERIMENTATION IN BIOLOGY
A major problem of physiology and pathology is the analysis of states, which cannot be studied directly in man, because they are experimentally inaccessible on account of ethical or technical grounds. An extremely important case is the terminal hypoxic state in man, characterised by gradually vanishing central control influences. There emerges the crucial problem of how far a system in a living organism is capable of a proper function without a central control, if the organism is to remain alive. If such a situation without central control is realised experimentally in the classical form, it leads mostly to a seriously mutilated organism, which is far from being normal. Moreover, it is hard to control such experiments if all central influences are abolished, e.g. if even hormonal influences are sufficiently inhibited. Such experiments are realisable in computer models. Computerised experimentation of this kind necessitates a very advanced quantitative model, realised after a thorough analysis of its sensitivity and after a proper identification. In living organisms, there are central control systems (respiratory - in our case - and other centers) and peripheral control mechanisms. The first one is represented by neuronal and hormonal activities. It is quick and, in principle, general, as far as its activity upon one system is concerned; specifity is attained by afferent information shaping. If this is distributed, nervous impulses can influence all systems of the body, as Seen after de-afferentation, intoxication with strychnine and in generalized anoxic convulsions, synchronous with the activity of the respiratory center in terminal states. These reactions are labile and able to change quickly in any direction. The second type of control is represented mainly by activity, leading to growth; it is slow and specific. It leads to different changes within one system (organ and tissue) and to its inhomogeneity, in relation to the intensity of local strain. The results are hardly reversible or irreversible. The changes, caused by the activity of the peripheral control mechanism, are the primary factor determining the characteristics of structure and behavior of pathologically changed parts of the body. It is clear that the organism organises its disease itself! In health, the peripheral parts and controlling mechanisms are beautifully shaped as to fulfi the needs of the body. Structural pathological changes, elicited by peripheral mechanisms, represent boundary conditions for the activity of the central control system. It could be shown that, even in pathologically changed respiratory 81 hr. J,Bio-Medical Computing (13) (19t32) 87-88 0020-7 101/82/0000-0000/$02.75 Q 1982 ElnevWNorth-Holland Scientific Publishers Ltd.
88
Letter to the Editor
systems, central influences are trying hard to preserve the optimal shape of the respiratory breathing pattern, even if this needs more energy and more control effort. If this at last is impossible within the existing frame of structural changes, the possibilities of central control are limited and strictly determined. This determination leads to the conclusion that in some terminal cases the living organism cam-rot but organise and control its own death. The introduction of computers into biology and medicine not only leads to computerised evaluation of the registered data and aids the process of diagnostics. On a higher plane this makes possible a formulation of relations and identification of working hypotheses. But the most important plane is direct experimentation with models and with simulated biological systems, able to be changed with the needs of the experimenter. Thus it is possible to prepare biological experiments in advance and to take advantage of heuristic possibilities of the computerised analysis. It is not quite certain whether the existing frame of mathematics will be sufficient to fulfil the needs of biology; probably mathematics is to be developed into biomathematics and new mathematical procedures and directions will be needed. In any case computerized experimentation shifts our experimental work into new, interesting dimensions of great practical significance. JOSEF DVOm Research Institute of Tuberculosis and Respiratory Diseases, Bulovka, 18000 Prague 8, Czechoslovakia (Received: 25 October, 1980)
COMPUTERISED EXPERIMENTATION IN BIOLOGY
A major problem of physiology and pathology is the analysis of states, which cannot be studied directly in man, because they are experimentally inaccessible on account of ethical or technical grounds. An extremely important case is the terminal hypoxic state in man, characterised by gradually vanishing central control influences. There emerges the crucial problem of how far a system in a living organism is capable of a proper function without a central control, if the organism is to remain alive. If such a situation without central control is realised experimentally in the classical form, it leads mostly to a seriously mutilated organism, which is far from being normal. Moreover, it is hard to control such experiments if all central influences are abolished, e.g. if even hormonal influences are sufficiently inhibited. Such experiments are realisable in computer models. Computerised experimentation of this kind necessitates a very advanced quantitative model, realised after a thorough analysis of its sensitivity and after a proper identification. In living organisms, there are central control systems (respiratory - in our case - and other centers) and peripheral control mechanisms. The first one is represented by neuronal and hormonal activities. It is quick and, in principle, general, as far as its activity upon one system is concerned; specifity is attained by afferent information shaping. If this is distributed, nervous impulses can influence all systems of the body, as Seen after de-afferentation, intoxication with strychnine and in generalized anoxic convulsions, synchronous with the activity of the respiratory center in terminal states. These reactions are labile and able to change quickly in any direction. The second type of control is represented mainly by activity, leading to growth; it is slow and specific. It leads to different changes within one system (organ and tissue) and to its inhomogeneity, in relation to the intensity of local strain. The results are hardly reversible or irreversible. The changes, caused by the activity of the peripheral control mechanism, are the primary factor determining the characteristics of structure and behavior of pathologically changed parts of the body. It is clear that the organism organises its disease itself! In health, the peripheral parts and controlling mechanisms are beautifully shaped as to fulfi the needs of the body. Structural pathological changes, elicited by peripheral mechanisms, represent boundary conditions for the activity of the central control system. It could be shown that, even in pathologically changed respiratory 81 hr. J,Bio-Medical Computing (13) (19t32) 87-88 0020-7 101/82/0000-0000/$02.75 Q 1982 ElnevWNorth-Holland Scientific Publishers Ltd.
88
Letter to the Editor
systems, central influences are trying hard to preserve the optimal shape of the respiratory breathing pattern, even if this needs more energy and more control effort. If this at last is impossible within the existing frame of structural changes, the possibilities of central control are limited and strictly determined. This determination leads to the conclusion that in some terminal cases the living organism cam-rot but organise and control its own death. The introduction of computers into biology and medicine not only leads to computerised evaluation of the registered data and aids the process of diagnostics. On a higher plane this makes possible a formulation of relations and identification of working hypotheses. But the most important plane is direct experimentation with models and with simulated biological systems, able to be changed with the needs of the experimenter. Thus it is possible to prepare biological experiments in advance and to take advantage of heuristic possibilities of the computerised analysis. It is not quite certain whether the existing frame of mathematics will be sufficient to fulfil the needs of biology; probably mathematics is to be developed into biomathematics and new mathematical procedures and directions will be needed. In any case computerized experimentation shifts our experimental work into new, interesting dimensions of great practical significance. JOSEF DVOm Research Institute of Tuberculosis and Respiratory Diseases, Bulovka, 18000 Prague 8, Czechoslovakia (Received: 25 October, 1980)