NEOPLASIA 7: CHEMICAL CARCINOGENESIS & Ames test скачать в хорошем качестве

NEOPLASIA 7: CHEMICAL CARCINOGENESIS & Ames test

A series of video tutorials discussing the topics for undergraduates in Pathology In this tutorial , i have discussed Chemical Carcinogenesis. Carcinogenesis ***Follow me**** http://ilovepathology.com/ Twitter :   / vijaypatho     / ilovepathology2   Facebook:   / ilovepathology   • Oncogenesis Mechanism of induction of tumors Carcinogen • A substance or agent which can induce cancer. • Types: 1.Chemical carcinogen 2.Physical carcinogen 3.Biological carcinogen History 1761 - Dr John Hill, London Physician Observed the association of nasal cancer among tobacco snuff users in men. 1775 - Percivall Pott, an English surgeon : increased Incidence of scrotal cancer in chimney sweepers in London. 1915 - Yamagiwa and Ichikawa, Japanese Pathologists: Multiple topical applications of coal tar to rabbit ears produced squamous cell carcinomas. First demonstration that a chemical could produce cancer in animals. 1930’s – Kennaway, a british Pathologist : showed for the first time that polycyclic aromatic hydrocarbons , such as dibenzanthracene, are tumorigenic in mouse skin 1940’s - James and Elizabeth Miller, Oncologists : first to find the relationship between metabolic activation, and tumorigenesis. Experiments demonstrating the initiation & promotion Tests For Chemical Carcinogenicity • Experimental induction • Tests for Mutagenecity( AMES’ TEST) • The Ames Test is an easy and inexpensive way to measure the MUTAGENICITY of a chemical. • Ames test does not determine if chemical is carcinogenic!!! • Rationale of test is that greater than 90% of all chemical mutagens have been shown to be carcinogenic in subsequent animal tests • The bacterium used in the test is a strain of Salmonella typhimurium that caries a defective (mutant) gene making it unable to synthesize the amino acid histidine from the ingredients in its culture medium. • However, some types of mutations (including this one) can be reversed, a back mutation, with the gene regaining its function. • These revertants are able to grow on a medium lacking histidine. ~-~~-~~~-~~-~ Please watch: "WARBURG EFFECT: Hallmark of CANCER. What, Why & How?"    • NEOPLASIA 6: WARBURG EFFECT: Hallmark of  ...   ~-~~-~~~-~~-~