Short Notes on Necrosis and Fluorescence Activated Cell Sorting (FACS)
(a) Necrosis
Definition
Necrosis is a form of irreversible cell injury that leads to premature cell death due to factors like trauma, infection, toxins, or lack of blood supply. It is often associated with inflammation and damage to surrounding tissues.
Key Features
- Uncontrolled cell death
- Swelling of cells and organelles
- Loss of plasma membrane integrity
- Leakage of cellular contents
- Inflammatory response in surrounding tissue
Causes
- Ischemia (lack of blood flow)
- Physical trauma or mechanical injury
- Infections (especially bacterial)
- Exposure to harmful chemicals or radiation
Types of Necrosis
- Coagulative necrosis: Common in heart and kidneys due to ischemia
- Liquefactive necrosis: Occurs in brain tissues and abscesses
- Caseous necrosis: Seen in tuberculosis infections
- Fat necrosis: Occurs in fat-rich tissues, like pancreas and breast
(b) Fluorescence Activated Cell Sorting (FACS)
Definition
FACS is a specialized type of flow cytometry that sorts a heterogeneous mixture of cells into different populations based on specific light scattering and fluorescent properties.
Working Principle
- Cells are labeled with fluorescent antibodies specific to surface markers.
- They are passed through a laser beam one by one in a fluid stream.
- Fluorescence is measured for each cell.
- Electrostatic charges are applied to the droplets containing the cells based on fluorescence.
- Charged plates then deflect cells into different collection tubes.
Applications
- Isolation of specific cell types (e.g., immune cells, stem cells)
- Diagnosis of diseases like leukemia and lymphoma
- Research in immunology and cancer biology
- Analysis of cell cycle and apoptosis
Advantages
- High speed and precision
- Ability to analyze and sort thousands of cells per second
- Quantitative and qualitative data collection
Conclusion
Necrosis is a harmful form of cell death that can lead to tissue damage and disease, while FACS is a cutting-edge technique that enables the detailed analysis and sorting of cells for both research and clinical purposes. Understanding both concepts is crucial for students of cell biology and medical science.