- •16. Neoplasia
- •16.1. Name the basic kinds of tissue growth changes.
- •16.3. Why tumoral process is considered to be the general biological phenomenon?
- •16.4. Are there features in character of tumoral process in humans and different kinds of animals?
- •16.5. What are the basic distinctions between benign and malignant tumours?
- •16.6. What are methods of experimental studying of tumours?
- •16.7. Name principal causes of malignant tumours occurrence.
- •16.8. Who and how for the first time has proved a role of chemical factors in occurrence of malignant tumours?
- •16.9. How are chemical carcinogens classified?
- •16.10. Give the examples of carcinogens of a natural and artificial origin.
- •16.11. Characterize carcinogenic action of polycyclic aromatic hydrocarbons (pah).
- •16.12. What is the feature of carcinogenic action of aromatic amines?
- •16.13. What is carcinogenic influence of nitrozo-compaunds characterized by?
- •16.14.Give examples of carcinogenic action of products of mushrooms life.
- •16.15. What meaning is put in concept "endogenous carcinogens"?
- •16.16. In what experiences possible participation of hormones in occurrence of malignant tumoral growth is proved?
- •16.17. What are chemical carcinogens of direct and indirect action? Give their comparative characteristic.
- •16.18. What properties of chemical substances cause their carcinogenic action?
- •16.19. What stages passes chemical carcinogenesis? What is their essence?
- •16.20. What is an explanation of the phenomenon of a tumoral progression?
- •16.21. What physical factors can matter in occurrence of malignant tumours?
- •16.22. Name the basic laws of carcinogenic action of an ionizing radiation.
- •16.23. What is "plastic" carcinogenesis? What are its features?
- •16.24. Who proved a role of viruses in occurrence of tumours and in what experiments?
- •16.25. What dna-containing viruses are oncogenic for animals and human?
- •16.26. What rna-containing viruses are oncogenic for animals and human?
- •16.27. Name stages of virus oncogenesis.
- •16.28. Name factors on which transforming action of viruses on a cell depends.
- •16.29. What are the viral oncogenes?
- •16.30. What are protooncogenes?
- •16.31 How are virus oncogenes and protooncogens classified?
- •16.32. What are cellular oncogenes? Name the basic mechanisms of transformation of protooncogenes into cellular oncogenes.
- •16.33. What are antioncogens?
- •16.34. What molecular mechanisms can underlie in virus oncogenesis?
- •16.35. What molecular mechanisms can be connected carcinogenesis, caused by action of chemical and physical factors?
- •16.36. Name features of growth of malignant tumoral cells in vitro conditions.
- •16.37. Name the basic features of growth of malignant tumours in vivo.
- •16.38. With what speed do malignant tumours grow? What factors is it defined by?
- •16.39. What violations of metabolism characterize malignant tumours?
- •16.40. What is invasiveness of tumours? How do malignant cells sprout in surrounding tissue?
- •16.41. What is metastasing? How is it carried out?
- •16.42. How do the tumours influence on an organism as a whole? Why cancer cachexy do develops?
- •16.43. What factors of an organism influence development of malignant tumours?
- •16.44. What mechanisms of antineoplastic protection exist in an organism?
- •16.45. Name the basic pathogenetic approaches to treatment of tumours.
16.43. What factors of an organism influence development of malignant tumours?
Development of a tumour is defined not only by properties of tumoral cells, but also influence of an organism on this process. The greatest value has:
a) Vascularisation of tumours. It is shown, that the maximal remoteness of tumoral cells from a gleam of blood vessels cannot be more than 1 - 2 mm. If the distance exceeds this size, cells of a tumour perish.
In a malignant tumour, as a rule, intensively sprout blood vessels. It is connected by that tumoral cells release so-called angiogenetical factor (angiogenine) which stimulates growth of capillaries and duplication of endothelial cells;
b) Hormones. Though tumoral process is independent, there are, however, tumours which show high hormonesensitiveness. It is, in particular, a cancer of mammary gland, uterus, ovaries, prostate. One hormone accelerate growth of the specified tumours, others slow down;
c) Condition of mechanisms of antineoplastic protection of an organism.
16.44. What mechanisms of antineoplastic protection exist in an organism?
I. Mechanisms of natural nonspecific resistance of an organism to tumours. Have no immunological specificity and do not demand preliminary immunization. They are carried out by the following cells:
a) NК-cells (natural killers). These are greater granular lymphocytes, being a version of 0- lymphocytes. They distinguish tumoral cells and destroy them;
b) LAK (the lymphokine-activated killers). They, as well as NK-cells, carry out cytolysis of tumoral cells;
c) Macrophages. Destruction of cells of a tumour by macrophages is carried out by phagocytosis and mechanisms of extracellular cytotoxicity.
Mechanisms of natural nonspecific antineoplastic protection are effective, if the quantity of tumoral cells in an organism does not exceed 103.
II. Reactions of the acquired (specific) antineoplastic immunity are caused by specific tumoral antigens and include as cellular, connected with function Т-lymphocytes, and humoral, connected with formation of antibodies, immune reactions.
The specified reactions are effective, if the quantity of cells in a tumour is from 103 up to 106. If their quantity exceeds 106 the condition of immunological depressions develops and the mechanisms of antineoplastic protection described above suppress.
16.45. Name the basic pathogenetic approaches to treatment of tumours.
1. Surgical removal. 2. Beam therapy (using of an ionizing radiation). 3. Chemotherapy. 4. Immunotherapy. 5. Increase of nonspecific resistance (for example, injection of Calmette’s vaccine).