PBL 5: Microscopy by Cristina Huezo Argüello https://padlet.com/cristina3huezo/9meu7bwll5r9bbvo MCB Group 1 en-us 2021-12-01 10:02:31 UTC 2021-12-01 10:08:44 UTC hello@padlet.com What is histology? cristina3huezo https://padlet.com/cristina3huezo/9meu7bwll5r9bbvo/wish/1922427507
  • The study of microscopic structures of tissues, focusing on relating physiology of cells to their function
    • Histopathology is the study of tissues infected by a disease, used for diagnosis and to determine at what stage and progress the condition of the patient. 

    ]]>     2021-12-01 10:03:36 UTC https://padlet.com/cristina3huezo/9meu7bwll5r9bbvo/wish/1922427507     How are tissues prepared? cristina3huezo https://padlet.com/cristina3huezo/9meu7bwll5r9bbvo/wish/1922428167
  • Tissue fixation → preserve the tissue to prevent autolysis or petrification 
    • Chemical fixation works by linking together amino acids, glutaraldehyde, forms cyclopentane C5H10 
    • Forming of methylene bridged to fix them 
    • Makes cells harder, easiest to section 
    • Use a scalpel to slightly cut it down and put it in another preservative 
    • One might have to add wax or resin to make it even harder

    1. Tissue processing 
    • Dehydrating tissue by increasing the amount of alcohol 
    • Clearing → use organic solves to remove the alcohol allowing paraffin wax to enter the tissue (embedding) 
      • Paraffin wax will solidify it more 

    ]]>     2021-12-01 10:04:04 UTC https://padlet.com/cristina3huezo/9meu7bwll5r9bbvo/wish/1922428167     What is H&E staining? cristina3huezo https://padlet.com/cristina3huezo/9meu7bwll5r9bbvo/wish/1922429061
  • Used for histology to look at the pattern and structure of cells in the sample
  • E stains the matrix , H stains the nuclei 
  • Provides the researcher with a very detailed overview 
  • Hematoxylin has an affinity for negatively charged molecules, while Eosin has an affinity for positively charged molecules
    • Hematoxylin → nucleic acids
    • Eosin → cytoplasm



    • ]]>     2021-12-01 10:04:42 UTC https://padlet.com/cristina3huezo/9meu7bwll5r9bbvo/wish/1922429061     How does it (H&E) help distinguish benign and malignant tumors? cristina3huezo https://padlet.com/cristina3huezo/9meu7bwll5r9bbvo/wish/1922429744
  • The same cells have different morphology
  • High nuclear to cytoplasm ratio 
  • H&E enhances nuclei and cytoplasm; altered in anaplastic cells, easier to see 
  • Since the nucleus is already enlarged, the clumped chromatin is observable 
  • Cancer cells have a significantly large cell (stained blue), bigger than other cells, invade other cells, and lose their shape

    • ]]>     2021-12-01 10:05:12 UTC https://padlet.com/cristina3huezo/9meu7bwll5r9bbvo/wish/1922429744     What is a biomarker? cristina3huezo https://padlet.com/cristina3huezo/9meu7bwll5r9bbvo/wish/1922430257 A biological molecule found in the blood or tissue that indicates the presence of a disease or process. ]]> 2021-12-01 10:05:35 UTC https://padlet.com/cristina3huezo/9meu7bwll5r9bbvo/wish/1922430257 What is a biomarker for breast cancer cells? (Found Online) cristina3huezo https://padlet.com/cristina3huezo/9meu7bwll5r9bbvo/wish/1922431119
  • Estrogen receptor (ER)
    • Bind to its ligand act directly as transcription factors
  • Progesterone receptor (PR)
  • Human epidermal growth factors 2 (HER2) 
  • Breast cancer that is ER-positive depends on the hormone estrogen to grow, while PR-positive means the tumor depends on the hormone progesterone to grow. 

    • ]]>     2021-12-01 10:06:10 UTC https://padlet.com/cristina3huezo/9meu7bwll5r9bbvo/wish/1922431119     What is immunohistochemistry? cristina3huezo https://padlet.com/cristina3huezo/9meu7bwll5r9bbvo/wish/1922431773
  • Use: Localize proteins 
  • Uses the chemistry of the body to detect the presence of antibodies
  • Antibodies are either purified (other non-specific antibodies are removed) or specific monoclonal (only recognize target molecules) 
  • Indirect and direct immunohistochemistry
    • Indirect → primary antibody binds to the antigen, the second antibody binds to the primary antibody, the second antibody has the marker 
    • Direct → the cell has a certain antigen and the body makes the antibody to attach to them (highly specific) 
    • Monoclonal antibodies are used to treat cancer cells, bring T-cells closer to cancer cells to facilitate an immune response 

    • ]]>     2021-12-01 10:06:35 UTC https://padlet.com/cristina3huezo/9meu7bwll5r9bbvo/wish/1922431773     What is fluorescent imaging? cristina3huezo https://padlet.com/cristina3huezo/9meu7bwll5r9bbvo/wish/1922432409
  • Fluorescent molecules absorb light at one wavelength and emit it at another, longer wavelength. 
  • There are two different filters; one to filter the light before it reaches the specimen and one to filter the light obtained from the specimen. 
  • This is used when coupling the fluorescent dye to an antibody which then binds to other molecules. Two dyes used:
    • fluorescein → green light emitted by blue light 
    • Rhodamine → red light excited by green-yellow light 
  • GFP (green fluorescence protein) not important, an an example 

    • ]]>     2021-12-01 10:06:57 UTC https://padlet.com/cristina3huezo/9meu7bwll5r9bbvo/wish/1922432409     What are anaplastic cells? cristina3huezo https://padlet.com/cristina3huezo/9meu7bwll5r9bbvo/wish/1922434987
  • Cancer cells that divide rapidly that have little resemblance to cells and act as undifferentiated cells, lose their characteristics.
    • Prominent nuclei
    • Increased nuclear to cytoplasm ratio
  • Anaplastic cells don’t always have to be cancerous 
  • Stage 1: Hypoplasia caused by an increased amount of cells due to proliferation
    • Might lead to cancer; accumulation of abnormal cell (precancerous condition) 
  • Stage 2: Adenoma 
    • Increase in cell number, benign tumor, the lumen gets filled with uncontrollable dividing cells, membrane breaks, nucleus changes cells, allows the cell to expand 
  • Stage 3: Carcinoma 
    • Epithelial cancer cell 
    • There is malignant cancer yet it has not spread
  • Stage 4: Invasive Carcinoma
    • It has spread and invaded other cells. 

    • ]]>     2021-12-01 10:08:41 UTC https://padlet.com/cristina3huezo/9meu7bwll5r9bbvo/wish/1922434987