Biochemistry of Free Radicals and Antioxidants

Study Notes

A free radical is an atom or molecule with one or more unpaired electrons.
This makes free radicals unstable and highly reactive because they tend to acquire electrons from other substances.

An antioxidant is a molecule stable enough to donate an electron to a free radical.
This neutralizes the free radical, reducing its capacity to cause damage.

Substances that induce oxidative stress, either by generating reactive oxygen species or by inhibiting antioxidant systems.

An imbalance between the production and accumulation of reactive oxygen species (ROS) in cells and tissues and the ability of the biological system to detoxify these reactive products.

Reactive Oxygen Species (ROS) are reactive chemical species containing oxygen.
- Examples include hydroxyl (OH), hydrogen peroxide (H2O2), superoxide (O2), peroxyl (RO2), and singlet oxygen (O2).
Reactive Nitrogen Species (RNS) are a group of compounds that include:
- Nitric oxide radical (NO), nitrogen dioxide radical (NO2), peroxynitrite (ONOO-), other oxides of nitrogen, and products arising when NO reacts with O2 and other free radicals.

Enzymatic Antioxidants
- Superoxide Dismutase (SOD)
  - Dismutates superoxide radicals to form hydrogen peroxide (H2O2) and oxygen (O2).
  - First line of defense against free radical formation.
  - Three isoforms (SOD1, SOD2, SOD3) are found in mammalian cells.
- Catalase
  - Found in nearly all living organisms.
  - Decomposes hydrogen peroxide to water and oxygen.
  - Protects cells from oxidative damage by ROS.

5 Moments for Hand Washing:
- Before touching a patient
- After touching a patient
- After touching a patient’s surroundings
- After touching body fluid
- Before a septic procedure
Purpose of Hand Washing:
- Prevent infection
- Remove dust and microbes
- Remove microorganisms
- Protect the patient
- Protect relatives
4 Types of Hand Washing:
- Routine Hand Washing:
  - Removes transient organisms
  - Use warm water
- Antiseptic Hand Washing:
  - Uses warm water and antimicrobial soap for 2-3 minutes, covering hands and fingers
  - Removes microorganisms and dust
Hands Evaluation Before Hand Washing:
- Short cut nails
- No wounds
- No accessories, except a wedding ring

Step 1: Wash hands with alcohol
Step 2: Surgical hand washing before surgical operations
Step 3: Use 13-5 ml antiseptic solution, covering hands to elbows
Step 4: Stand in front of the sink
Step 5: Leave space and bend slightly
Step 6: Control the water rate
Step 7: Turn off sleeves to elbow
Step 8: Wet your hands
Step 9: Wash from cleanest to least clean areas
Step 10: Make your hand down
Step 11: Take some soap then
Step 12: Rub each thumb clasped in the opposite hand using a rotational movement
Step 13: Rub tips of fingers in opposing palm in a circular motion
Step 14: Rub each wrist with opposite hand
Step 15: Rinse hands with water
Step 16: Use elbow to turn off tap
Step 17: Dry thoroughly with a single-use towel

Purpose: Prevent the spread of infection
Indications:
- Contact with body fluid
- Contact with sterile areas
- Contact with septic procedures
Types of Gloves:
- Open method
- Closed method