Medical Biochemistry Quiz

Laboratory Testing Groups

• Basic Metabolic Panel (BMP):

  • Kidneys
  • Acid/base balance
  • Electrolytes
  • Blood Glucose level

• Comprehensive Metabolic Panel (CMP):

  • Kidneys
  • Liver
  • Electrolytes
  • Acid/base balance
  • Blood glucose
  • Blood proteins

• Liver Tests:

  • Proteins (total protein & albumin)
  • ALP (alkaline phosphatase)
  • ALT (alanine aminotransferase) (SGPT)
  • AST (aspartate aminotransferase) (SGOT)
  • Bilirubin (total & direct)

• Renal Profile:

  • Albumin
  • Urea/BUN (blood urea nitrogen)
  • Electrolytes and anion gap
    • Sodium
    • Potassium
    • Chloride
    • Bicarbonate
    • Phosphorus
    • Calcium

Cardiac Panel Profile/Coronary Risk Profile/Lipid Profile

• Cholesterol
• HDL-cholesterol
• LDL-cholesterol
• Triglycerides

Diabetes Mellitus Profile

• Screening: Urinalysis
• Confirmation:
  • Fasting blood glucose = > 7.0 mmol/L
  • Random glucose = > 11.0 mmol/L
  • OGTT/MGTT = > 11.0 mmol/L
  • Monitoring: HbA1c > 6.5%

Anemia Profile

• Total iron binding capacity
• Iron
• Vitamin B12
• Folate, RBC
• Transferrin
• Ferritin

Hypertension Profile

• Urinalysis, urine protein
• Urinary albumin, BUN, creatinine, eGFR
• Calcium
• TSH (thyroid stimulating hormone) and T4
• Fasting glucose, A1c
• Potassium
• Basic metabolic panel (BMP)
• Lipid profile

Aldosterone and Renin

• Cortisol and dexamethasone test
• Catecholamines and d metanephrines
• Complete blood picture

Arthritis Profile

• C-reactive protein (CRP)
• Sedimentation rate
• Uric Acid

Bone/Joint Profile

• Calcium
• Uric acid
• RA Factor (rheumatoid arthritis)
• Phosphate

Pancreatic Profile

• Amylase
• Insulin fasting
• Lipase
• C-peptide

Thyroid Profile

• TSH Tests
  • T3 bound to protein
  • FT3

Parathyroid Profile

• Vitamin D tests
• Calcium
• Phosphorus

Drug Toxicology Profile

• Therapeutic drug monitoring
  • Barbiturates
  • Phencyclidine (PCP)
  • Amphetamines
  • Cocaine
  • Methamphetamines
  • Marijuana
  • Opiates

Amino Acids and Proteins

• Protein:

  • Large molecules
  • Made up of chains of amino acids
  • Found in every body cell
  • Involved in most body functions
  • Sequence of amino acids determined by DNA

• Amino Acid Structure:

  • Amino group
  • Carboxyl group
  • R-group (side chain)

• Amino Acid Properties:

  • Building blocks of proteins
  • Organic compounds
  • Zwitterions and amphoterics

• Types of Amino Acids:

  • Non-essential
  • Essential

• Non-Essential Amino Acids:

  • Body produces these
  • Liver produces nearly 80% of amino acids

• Essential Amino Acids:

  • Body cannot produce them
  • Must be supplied through diet

• 20 types of amino acids: -Glycine, alanine, proline, valine, leucine, isoleucine, methionine -Serine, threonine, cysteine, asparagine, glutamine -Phenylalanine, Tyrosine, tryptophan -Aspartate, glutamate -Lysine, arginine, histidine

• Protein bonds: -Dipeptide, tripeptide, oligopeptide, polypeptide

• Structure of protein: -Primary, secondary, tertiary, quaternary

Non-protein Nitrogenous Compounds

• Amino Acid Functions:

  • Energy use
  • Vitamin 65 and coenzyme A constituent -Immune function (tumor & cancer retardation, healing) -Liver detoxification -Muscle metabolism -Stamina -Protective liver function -Production of collagen, elasticity, and skin texture

• Transamination:

  • Transfer of amino group from amino acid to keto acid to form new amino acid and keto acid
  • Catalyzed by transaminases (aminotransferases)
  • Kidney function -regulating acid-base balance and excreting nitrogenous waste
  • Brain function -synthesis of neurotransmitters (glutamate, aspartate, GABA)

• Deamination:

  • Removal of amino group from amino acid

• Defects in amino acid metabolism:

  • Phenylketonuria (PKU)
  • Tyrosinemia, alkaptonuria, and albinism
  • Homocystinuria and hypermethioninemia
  • Cystinuria and cystinosis and sulfite oxidase deficiency
  • Hartnup's disorder
  • Maple syrup urine disease (MSUD)
  • Nonketotic hyperglycinemia (glycine encephalopathy)

• Aminoaciduria:

  • Presence of elevated amino acids in urine
  • Can be primary (inherited enzyme deficiency or inborn error) or secondary (due to kidney/liver dysfunction)

Newborn Screening Tests

• Guthrie Test:
  • Detects phenylketonuria (PKU)
  • Involves placing a blood sample on filter paper
  • Bacterial growth indicates elevated phenylalanine levels (positive result

Urea/Blood Urea Nitrogen (BUN)

• BUN measures the amount of urea nitrogen in blood.
• Indication of kidney function.
• Rises more rapidly than serum creatinine (Less sensitive indicator of declining renal function).
• Normal values differ based on gender and age.

Azotemia

• Elevated urea concentration in blood.
• Often caused by: impaired renal function, congestive heart failure, dehydration, shock etc.

Uric Acid

• Waste product produced from protein metabolism.
• Excreted by kidneys & bowels.
• Increased levels can lead to gout and other issues.
• Normal values vary.

Chronic Kidney Disease (CKD) Stages

Lipid and Fatty Acids

• Lipid - various molecules, insoluble in water. Types - triglycerides, cholesterol, phospholipids
• Fatty acids - mostly straight-chain monocarboxylic acids. Saturated fatty acids, Unsaturated fatty acids.
• Triglycerides - fatty acids esters of glycerol, Main lipids in diets.
• Cholesterol - steroid present in the diet and liver that's part of cell membranes, steroid hormone synthesis.
• Phospholipids - similar structure to triglycerides, major component of cell membranes.

Lipoproteins

• Lipoproteins - transport cholesterol, triglycerides, and phospholipids in plasma.
• Chylomicron = largest, carries dietary triglycerides
• VLDL = endogenously produced triglycerides
• LDL = carries cholesterol to tissues
• HDL = carries cholesterol from tissues to liver
• Enzyme Systems (LPL, LCAT) crucial in lipoprotein metabolism

Glucose Metabolism

• Homeostasis:
  • Pancreas release insulin in response to high blood sugar
  • Insulin helps regulate blood glucose levels
  • Conversely, glucagon increase blood sugar when levels decrease.
• Hypoglycemia: Very low blood sugar level, can be caused by prolonged fasting, excessive physical activity, and insulin overdose.

Hormones (Insulin, Glucagon) & Other factors affecting Glucose Regulation

 -Insulin: Reduces blood sugar.

• Glucagon: Increases blood sugar.
• Hypoglycemia: Low blood sugar.

Thyroid Hormone

• Main function = regulate metabolism, growth, and energy balance.
• Thyroid hormone (T3, T4)
• TRH (thyrotropin-releasing hormone) stimulates pituitary to release TSH (thyroid-stimulating hormone) which stimulates thyroid.
• Negative feedback loops help to maintain homeostasis in thyroid hormone balance.
• Goiters - swelling of the thyroid gland.

Hyperthyroidism & Hypothyroidism

• Hyperthyroidism - overactive thyroid gland (symptoms - Weight loss, increased appetite, heart palpitations, nervousness etc.)
• Hypothyroidism - underactive thyroid gland (symptoms - Weight gain, fatigue, depression etc.)