01:447:245 Lecture Notes - Lecture 4: Riboflavin, Hif1A, Porphyrin
Document Summary
Endogenous and exogenous stressors aid in the carcinogenic process. Dna hypo, hyper-methylation, histone tail and transcriptional modification. Chemical injury (ccl3 free radical interacts in liver) Dna methylation: an important regulator of gene transcription. Dna hyper- and hypo-methylation and methyl binding protein activity regulate normal gene expression. Histone tail modification alters the way a stretch of chromatin is expressed a. b. Alpha particles ( e. g. radon from decaying radium/uranium) produce free radical damage to cells. Large mass(proton + neutron) so travel short distance, effects usually seen at surface level (skin cancer) Alpha particles can penetrate cut or opening (e. g. lung cancer) Beta particles (e. g. decaying i-125/131) also produce free radicals. Fast moving electrons; fraction size of alpha particles & more penetrating. Sometimes used in benign thyroid tumor therapy (problems later on?) Gamma rays, x-rays, and most uv produce fast moving photons below 400nm: uvb most common. Uv radiation produces various levels of cellular damage.
