ISSN:
1432-1440
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Description / Table of Contents:
Summary The phenomenon of carcinogenesis, considered a consequence of several consecutive steps, is being discussed from the biochemical point of view at the molecular level. The term “initiating stage” covers the action of carcinogens primarily causing mutations of the genetic material, especially of the DNA. Tumor promotion, the second stage, may be divided into various steps. Direct consequence of mutations having hit the regulator, operator, or structural genes will be the lost of inducibility, control, or synthetic action of the operon concerned. Provided that these mutations are not lethal the cell will loose specific functions and regain higher mitotic activity indicating the atavistic change. This may cause transcriptions of mutations having occurred in DNA-regions which have been dormant thus far. Exogenic stimulations of mitotic activity accelerates the selections of prospective tumor cells, which possibly have developed resistance against rather disadvantageous, e.g. toxic, influences resulting either from the intensified metabolic turnover, or exogenic application. After having lost contact inhibition the cell is to be considered an autonomic tumor cell. As a result of an attempt to understand the tumor promoting potency of phorbol-esters isolated from croton oil a hypothesis is put forth which interprets the cocarcinogenic action as a consequence of the simultaneous irritation, intoxication, and surface-activity.
Notes:
Zusammenfassung Das Phänomen der Carcinogenese wird als Folge verschiedener konsekutiver Schritte diskutiert. Der Versuch einer Analyse der mit mutierenden Reaktionen zwischen Carcinogenen und chromosomaler DNS („Initialphase“) beginnenden Kausalkette erfolgt aus biochemischer Sicht auf molekularer Ebene. Der tumorpromovierende Effekt cocarcinogener Substanzen während der „Realisierungsphase“ wird am Beispiel der Phorbolester aus Crotonöl als — vorläufig hypothetischer — Eingriff in Regulationsmechanismen interpretiert und gemeinsam mit experimentell fundierten Vorstellungen zu Thesen zusammengefaßt, die den Beitrag abschließen und hier nicht wiederholt werden sollen.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01725672
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