- •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. Neoplasia
16.1. Name the basic kinds of tissue growth changes.
Two kinds of tissue growth changes are distinguished: hyperbiotical and hypobiotical processes. To the first group belongs: a) hypertrophy and hyperplasia; b) regeneration; c) Neoplasia (tumour). To the second - an atrophy; a dystrophy and a degeneration.
16.2. What is the neoplasia process? What kinds of tumours do exist?
Neoplasia process is a typical pathological process which essence is an unlimited, noncontrollable growth of the tissue which hasn’t been connected with the general structure of the injured organ and its functions.
There are two kinds of tumours exist: benign and malignant.
16.3. Why tumoral process is considered to be the general biological phenomenon?
Tumoral process has the general biological character because tumours arise both at animals, and at plants. Tumours are found at all kinds of multicellular alive organisms (at insects, fishes, amphibians, reptiles, mammals).
16.4. Are there features in character of tumoral process in humans and different kinds of animals?
In humans 90 % of all malignant tumours have an epithelial origin, so are cancer. At the same time at large horned livestock, horses, pigs 80 % of malignant tumours occur from blood cells, so are hemoblastoses, and at dogs 50 % of malignant new growths are represented as sarcomas - a tumour of a connective tissue cells.
16.5. What are the basic distinctions between benign and malignant tumours?
1. Benign tumours consist of well differentiated cells. These tumours keep typical structure of a tissue which they have occurred from. At the same time malignant tumours are characterized by loss of a differentiation of cells, simplification and atypical structures.
2. Benign tumours often grow slowly; their growth can stop, and sometimes also observed return development (regression). The malignant tumours are characterised by fast growth which does not stop spontaneously. Spontaneous regress of such tumours is unknown.
3. Benign tumours have a capsule and grow expansively, so they do not sprout in surrounding healthy tissues, but move apart them. Growth of malignant tumours is invasive (infiltrative). They have no capsule and sprout in surrounding tissues.
4. Benign tumours do not give metastases while malignant usually give metastasises.
5. Benign tumours are well treated by the surgical treatment, and lethal outcomes, do not happen as a rule. Malignant tumours at absence of treatment lead to death.
16.6. What are methods of experimental studying of tumours?
There are such methods of experimental modelling of tumours as the induction, transplantation and an explantation.
The method of an induction provides reproduction of malignant tumours by introduction of carcinogenic factors in an organism. More often with this purpose chemical carcinogenic substances and out of cells filtrates of a tumoral tissue containing oncogenic viruses are used. Besides with the purpose of an induction of tumours physical influences (x-ray radiation, radioactive participles, ultra-violet radiation) are sometimes used.
The transplantation method is reinoculation of tumours from one animal to another. For the first time it was carried out by M. Novinskiy in 1876. For successful transplantation of a tumour following conditions are important: a) transplantation should be carried out between the individuals of one kind of animals; b) alive viable tumoral cells should be intertwined; c) transplantation should be made in sterile conditions in order to prevent inflammatory process in a tissue.
The method of an explantation is a cultivation of a tumour in a culture of tissue outside of an organism. This method enables to study influence of various factors on tumoral growth, to carry out the search of methods of therapy of malignant tumours.