[The initial stage of disease].
The many-year experience of comparing the clinical picture of human disease with its pathological picture indicates that man begins to be aware of the pathological process typical of a given disease in many cases after some, not infrequently long period after its initiation and against the background of already developed morphological changes of organs and tissues. This difference in the time between morphologically initial and clinically early manifestation of disease may be explained by the existence in the body of a strong system of compensatory-adaptive reactions directed to the preservation of homeostasis. When these reactions are disturbed, homeostasis is broken and the disease becomes clinically manifest. A disease may be diagnosed early only when it is recognized in this "latent" period. It is in this period that the damage ("break" according to Pavlov) of the regulating systems frequently far from the target organ occurs. Thus, hypertension arises when the centers regulating the constant level of arterial pressure are damaged, while the entire pathology of hypertension is the effect of this damage. Mammary cancer is the effect of dyshormonal damages occurring in endocrine glands. Many diseases of the stomach are associated with primary involvement of various parts of the central and vegetative nervous system. Damages of the immunocompetent system and disturbances of immunological homeostasis are primary in diseases of the connective tissue with immune disorders and determine their clinical pattern and morphology. The results of morphological investigations performed by modern methods indicate that there are no functional diseases and that each disease has its material substrate determined at all levels of organization beginning from molecular and subcellular and ending with systemic. The material substrate of disease is formed from alterations at the site of the initial lesion and alterations in the target organ in which this lesion is manifested externally. The task of the current medicine is to recognize the morphological and clinical essence of the initial period of disease as an entity which is very important for early diagnosis.