Biochem lecture 4 Flashcards
(32 cards)
Between what 2 things does “normal” plasma enzymes (PE) levels represent a balance?
1- the rate of synthesis and release into plasma during cell turnover, and
2- the rate of clearance from the circulation
what are 3 physiological processes that may result in PE levels mean?
1- increase in cell damage
2- proliferation of cells
3- reduced clearance from plasma
what are 2 physiological processes that may result in a decrease in PE levels (rare occurrence)?
1- reduced synthesis
2- congenital or inherited variants
How can we analyse PE levels in a more useful way (3 ways)?
1- one or more enzymes being analysed
2- isoenzymes differentiation (ex: CK: MB, BB, MM)
3- serial enzymes
What are 4 possible causes of increased PE levels?
1- non-specific illness
2- moderate exercise
3- large intramuscular injection
4- drugs
What are 3 factors in a patient that influence the results of a blood test on PE levels?
1- age
2- sex
3- physiological conditions
Transaminases
- 2 types
- which organs are they found mostly
- what may a marked increase mean for both?
- what may a moderate increase mean for both?
2 types:
. ALT (Alkaline T.) - found mostly in LIVER (tip: L-L)
. AST (Aspartate T.) - found mostly in Myocardium, Sk. muscles and Liver
Marked increase in AST and/or ALT:
. MI
. Acute or Toxic Hepatitis
. Circulatory failure
Moderate increase in AST and/or ALT:
. sk. muscle disease
. Liver disease: cirrhosis, mononucleosis, cancer
. cholesterol
. post: trauma, surgery (less so if raised ALT)
. severe haemolytic episode
Creatine Kinase (CK)
- main 3 organs found in…
- 3 isoenzymes, and where they are found most
- what may a marked increase mean?
- what may a moderate increase mean?
. Muscles: Skeletal, Myocardium
. Brain
Marked increase may indicate:
- MI (CK-MB)
- Shock and circulatory failure
- muscular dystrophies (CK-MM)
Moderate increase may indicate:
- post-trauma: muscle injury, surgery (for about a week)
- physical exertion
- IM injection
- hypothyroidism
- alcoholism
CK-MB
Creatine kinase isoenzyme MB
. myocardium: 35% CK-MB, 5% CK-MM
CK-MM
Creatine kinase isoenzyme MM
. Skeletal muscles
CK-BB
Creatine kinase isoenzyme BB
. Brain
Amylase
. action
. main diagnosis if found elevated in plasma
Pancreatic digestive enzyme
. allows b/d of starch and glycogen to maltose
. If plasma levels raised: ACUTE pancreatitis
Alkaline Phosphatases (ALP)
- action
- 2 isoenzymes’ organs
- main 5 organs found in…
- what may raised levels of ALP mean?
. Action: hydrolysis (b/d) of phosphates in high pH
. 2 isoenzymes: bone, liver
. found mostly in:
- osteoclasts (bone)
- cells of hepatobiliary tract (liver, gall bladder)
- placenta
- intestinal wall
- renal tubules
. Raised ALP levels may indicate:
- bone disease (rickets/osteomalacia, Paget)
- Liver disease (cholestasis)
- Tumour (bone, liver or direct tumour)
Gamma-Glutamyl Transferase (GGT)
- main organs
- main indication of raised levels
- patient factor that affect levels
Liver, Kidneys, Pancreas, Prostate
Raised levels may indicate:
- alcoholism, drugs
- liver disease (cholestasis, hepatocellular damage)
Usually levels higher in men > women
- Heart disease / MI, and plasma enzymes activity
- other more sensitive/specific? blood findings
- Raised CK-MB: can be detected from 6 hours after infarct, with peak levels at 18-24 hours
- Cardiac Troponin I and T
Liver disease
- Raised AST, ALT, ALP, GGT
Cholestasis
- ALP
- GGT
Muscular dystrophy
- CK-MM
- AST, ALP
Neurogenic myopathies
PE Levels usually normal
List relevant plasma enzymes
- Transaminases (AST, ALT)
- Phosphatase (ALP and bone or liver IEs)
- Creatine Kinase (CK and IEs: MM, BB, MB)
- GGT
- Amylase
Name the 3 main functions of plasma proteins
1- inflammatory response and infection control (ex: CRP)
2- transport (ex: LDL, transferrin)
3- control of ECF (ex: albumin, sodium)
Plasma proteins indicating acute inflammation
- C-Reactive Protein (CRP, a complement activator, raise rapidly in acute inflammation)
- ESR
- IgM, IgG (first response)
- WBCs: Neutrophilia, Lymphocytes etc
5 Plasma proteins indicating Rheumatoid or AI inflammation
ESR, RhF, ANA, IgM, IgG
ANA is NOT found in which autoimmune inflammatory disease? (but found in which ones?)
Not in: Ankylosing Spondylitis, Reiter’s syndrome
found in: RA, SLE, Scleroderma, Sjogren
