Carcinogenic substances

Carcinogenic substances - substances of different chemical structure, causing malignant tumors.
The concept of carcinogenic substances has arisen on the basis of supervision over occupational cancer - skin cancer among chimney sweeps and urinary bladder cancer in workers of aniline-dye industry. There are several hundred of carcinogenic substances belonging to different classes of compounds, hydrocarbons, amines, etc. But absolutely reliable chemical carcinogens not more than 30-40.
All of carcinogenic substances can be divided into three groups: 1) substances directly local actions, 2) remote organotropic action and 3) multiple steps. The effect of the substance of the latter two groups is through the products of their metabolism in the body (metabolites).
Carcinogenic substances cause malignant tumors only after a significant period of time (for a person 15-20 years) after the commencement of their effect on the organism. Develop the tumor gradually from previous them growths of tissue, called precancerous (precancerous) changes.
Along with exogenous carcinogens exist and endogenous that occur in the body. They can be formed when violations hormonal balance, metabolic steroids and tryptophan.
The effect of carcinogenic substances depends on the dose and duration of their action. This is based on prevention of a number of malignant diseases.
In the USSR discontinued undoubted carcinogenic substances: betanaphthylamine, 3,3'-dichlorobenzidine, some aminoazobenzene, etc., and the production of benzidine sealed. Methods are developed exception of carcinogens from shale and other resins. Very important are measures of personal hygiene. The important role played prevention of air pollution and wastewaterthat can be achieved by improved fuel combustion, neutralization of exhaust gases of internal combustion engines, control of industrial emissions.
Sometimes a malignant tumor occurs in humans in connection with the Smoking of tobacco, as in tobacco smoke contains carcinogenic substances. Prevention is in the fight against harmful habit.