MED102 General Chemistry - Trace Elements & Isotopes

Discuss the importance of trace elements in life and give examples of trace element deficiencies.
Define radioactive isotopes and give examples of their use in medicine.

An essential element is one required for life, without which life would cease.
The four main elements that make up 96% of living matter are Carbon (C), Hydrogen (H), Oxygen (O), and Nitrogen (N).
A few other elements make up the remaining 4% of living matter.
Trace elements are required in very small quantities (<0.01%) by organisms.

The periodic table displays elements essential for humans in purple, suggested in light gray, and nonessential in light green shades.

Oxygen is the most abundant element in the human body (65%).
Other significant elements include carbon (18.5%), hydrogen (9.5%), nitrogen (3.2%), calcium (1.5%), phosphorus (1.0%), potassium (0.4%), sulfur (0.3%), sodium (0.2%), chlorine (0.2%), and magnesium (0.1%).
Trace elements (e.g., boron, chromium, cobalt, copper, fluorine, iodine, iron, manganese, molybdenum, selenium, silicon, tin, vanadium, zinc) are present in very small quantities (<1%).

Trace elements are essential for health, required in small amounts.
Examples include iron, iodine, zinc, selenium, manganese, copper, fluorine, molybdenum, chromium, and cobalt.

Iodine is essential for making thyroid hormones (T3 and T4).
Iodine deficiency leads to goiter (enlarged thyroid gland).
Symptoms of iodine deficiency include swelling in the neck, fatigue, weakness, dry skin, changes in heart rate, problems during pregnancy, unexpected weight gain, hair loss, feeling colder than usual, trouble learning or remembering, and heavy or irregular periods.
Dietary sources of iodine include seaweed, fish (cod, tuna), seafood (shrimp), dairy products (milk, yogurt, cheese), iodized salt, eggs, and dried plums (prunes).

Iron deficiency leads to iron deficiency anemia.
Anemia is a condition where the blood lacks adequate healthy red blood cells to carry oxygen to the body's tissues.
Symptoms of iron deficiency include extreme fatigue, weakness, pale skin, brittle nails, chest pain, fast heartbeat or shortness of breath, headaches, dizziness, cold hands and feet, mouth ulcers, and unusual cravings for non-nutritive substances.
Dietary sources of iron include legumes (beans, lentils, chickpeas, peas, soybeans), liver, shellfish (oysters, clams, mussels), spinach, broccoli, dried fruits, eggs, iron-fortified cereals, red meat (especially beef), and poultry.

Zinc is involved in numerous cellular processes and is crucial for 100+ enzymes.
Zinc plays essential roles in immune function, protein synthesis, wound healing, DNA synthesis, and cell division; it is crucial for normal growth and development.
Symptoms of zinc deficiency may include eye lesions, skin lesions and inflammation, poor wound healing, reduced resistance to infections, mental confusion, poor learning ability, changes in hair and nails, and anemia.
Common food sources of zinc include oysters, chicken, cheddar cheese, cashews, watermelon seeds, almonds, milk, red meat, yogurt, pumpkin seeds, and salmon.

Fluorine is a trace mineral, needed in small amounts daily.
Natural sources include fish, tea, and fluoridated tap water.
Fluorine deficiency can lead to increased dental caries and possibly osteoporosis.

Isotopes are atoms of the same element with the same number of protons (atomic number), but different numbers of neutrons (different mass number).
Examples include Hydrogen-1 (protium), Hydrogen-2 (deuterium), and Hydrogen-3 (tritium).

Radioisotopes are isotopes with unstable nuclei, which decay to emit energy and particles to become stable.
They are used widely in nuclear medicine for imaging and treatment.

Radioisotopes have numerous clinical applications, including disease treatment (radiotherapy), disease diagnosis (imaging), assessment of disease severity, and treatment monitoring as well as sterilization of medical equipment.

Radiotherapy uses radiation to damage the DNA of rapidly dividing cells, to control or eliminate cancerous growths.
It can cause side-effects such as skin problems, fatigue, and hair loss.
Radiotherapy is specifically effective against rapidly dividing cells such as those found in a tumor, as rapid-division cancer cells are more vulnerable to damage by radiation. This method has reduced and minimized the negative and detrimental effects on normal cells and tissues.

Radioactive iodine (I-131) is used to treat hyperthyroidism by gradually shrinking the thyroid gland
After treatment, most patients develop hypothyroidism and need to take thyroid hormone supplements.
Iodine-131 is used to treat thyroid cancer, destroying any leftover thyroid tissue removed by surgery or thyroid cancer that has spread to lymph nodes.

Cobalt-60 is used as a radiation source in external radiation procedures, such as gamma knife radiosurgery.
Radiotherapy aims to target ionizing radiation at cancer cells, damaging their DNA, preventing their ability to grow and divide.

Radioisotopes used for diagnostics emit gamma rays or positrons that escape the body, allowing imaging of organs and tissues.
The radioisotope used for scans must release sufficient energy, while its half-life must be short to prevent excessive radiation exposure.

Positron Emission Tomography (PET) scans use radioactive isotopes as tracers to image functional processes in the body.
A radioisotope (tracer) is introduced into the body as part of a biologically-active molecule.
PET scans provide 3D images, distinguishing bone and soft tissues effectively.

PET-CT combines PET and CT scans to provide co-registered images, offering a 30% increase in diagnostic accuracy over traditional methods.
It's a powerful tool for diagnosing various diseases, from dementia to cardiovascular diseases, and cancer.

SBA Question 1: Iron deficiency is the correct answer(d
SBA Question 2: Iodine deficiency is the correct answer (C).
SBA Question 3: Hair loss is a possible short-term side effect of radiotherapy (True).
SBA Question 4: Isotopes have the same number of protons (atomic number), and different number of neutrons (False).