Lecture 3 Infectious disease cancer Infectious disease when a pathogenic organism negatively affects the host Robert Koch first to link Bacillus anthracis to anthrax Had a set of rules postulates Proof of germ theory by isolating the cause of anthrax and showing it to be a bacterium pathogen must always be found in a diseased individual but absent in a healthy individual pathogen must be isolated and grow in a pure culture identified using nutritious matter pathogen from the pure cultures must cause disease when put into a healthy susceptible host same pathogen must be recovered from the newly diseased host In the 1900 s half of the causes of disease was due to some infectious disease but in 1997 it significantly dropped However the infectious disease mortality rate has been up since 1980 because of antibiotic resistance Cancer Hippocrates first recognized the difference between benign and malignant tumors Cancer is an umbrella term that refers to over 200 diseases that share 2 common characteristics An uncontrolled growth of cells The ability to invade and damage normal tissues either locally or at distant sites of the body How cancer develops Body is made up of hundreds of different types of cells which behave differently Same DNA but different roles Life of cell is mapped out by genes coded instructions in its nucleus When instructions relating to cell multiplication and dying are wrong and the cell may start dividing uncontrollably The cell may not die when it should and may become immortal so it continues to divide until a tumor forms Major types of new tissue growth Dysplasia pre cancerous Neoplasia what we associate with cancer tumor growth Neoplasm abnormal tissue growth where cells divide uncontrollably leading to a tumor Tumor swelling caused by fluid build up or cell accumulation can be benign or malignant Are self contained localized and have a well defined perimeter Grow slowly expands outwards from a central mass Are only dangerous when they compress surrounding tissues it can restrict blood flow Tumors Benign Malignant Not self contained Not localized process called metastasis where they shed cells that travel through Their growth is an irregular invasion of cells bloodstream and infect tissues at other locations Tumor grade cancer survival Biopsy doctor removes a sample of tissue if a tumor is suspected to be malignant GX grade cannot be assessed undetermined grade G1 well differentiated low grade G2 moderately differentiated intermediate grade G3 poorly differentiated high grade G4 undifferentiated high grade lower grade higher survival rate the more unorganized the more highly undifferentiated Tumor grade the microscopic appearance of cancer cells is associated with 5 year survival rates Tumor stage how large tumor has grown and how far it has spread Based on location of the primary tumor size number and lymph node involvement Naming cancers prefix meaning Chondro cartilage Erythro red blood cell Adreno gland Hemangio blood vessels Hepato liver Lipo fat Lympho lymphocyte Melano pigment cell Myelo bone marrow Myo muscle Osteo bone Different types of cancers Leukemia cancer of the blood bone marrow No tumor forms but there s an increase of immature white blood cells Lymphoma occurs when B or T cells divide faster live longer than normal Develops in lymph nodes spleen bone marrow blood or other organs Eventually a tumor forms Types of Carcinomas In the majority of cancers 85 are carcinomas Squamous cells that line different parts of the body mouth esophagus airways etc Adeno cells form the lining of all the glands in the body and can be found in organs stomach ovaries kidneys etc Transitional cells only found in the lining of the bladder parts of the urinary system Basal cells found in one of the layers of the skin
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