Lecture 24 Flashcards
What are isozymes?
catalyze the same biochemical reaction and the same enzyme has multiple forms
can be used as an injury marker
What is the reaction creatine kinase catalyzes?
At high ATP levels creatine phosphate (CrP) is formed
At high CrP levels, ATP is formed using the CrP
What are the three isozymes of creatine kinase?
- CK-BB (CK-1)
- CK-MB (CK-2)
- CK-MM (CK-3)
What form of creatine kinase is most present in the brain?
CK-BB or CK-1
When are CK-BB or CK-1 levels increased in the body?
Elevated after CNS damage
What are the forms of creatine kinase found in the heart and in what percentages are they present?
CK-MB (30%)
CK-MM (70%)
When are are CK-MB and CK-MM levels elevated in the body?
After a MI
What isozymes are found in skeletal muscle, in regards to creatine kinase?
98% is CK-MM
2% is CK-MB
When would serum CK-MM levels be elevated in the body?
this may be seen in patients with rhabdomyolysis and/or muscular dystrophy
How can hemolytic anemia be tested?
the severity of hemolytic anemia can be measured by the increase of LDH in the serum following RBC damage
What forms of LDH are elevated after an MI?
An increase in LDH-1 and LDH-2 isozymes in the blood
Explain the time frame for MI markers?
CK-MB levels will peak after 24 hours and then LDH levels will peak after 48 hours
What are the criteria for indication of an MI?
A. the CK-MB/total CK ratio is greater than 6 percent
B. The ratio is greater than 3 percent and troponins are increased
What are the purpose of troponins?
They are involved with muscle contraction
What isozymes of troponin are measured as heart injury markers?
Cardiac troponin I (cTnI) - inhibition of actomyosin
Cardiac troponin T (cTnT) - tropomyosin binding
In order to be diagnosed with MI, what must must be accumulated in the blood?
- increase in cardiac troponins (cTnI or cTnT)
2. increase in CK-MB
What method is used to measure MI injury markers?
ELISA
What are the liver function test examples?
- ammonium would be high
- albumin would be reduced
- bilirubin would be high
What can be used to determine liver membrane integrity?
- ALT (alanine aminotransferase)
2. AST (aspartate aminotransferase)
What does a high ALT to AST ratio indicate?
hepatic viral infection
What does a high AST to ALT ratio indicate?
hepatic alcohol damage
What can extra-hepatic bile ducts be obstructed by?
Gallstones or tumors
How can intra-hepatic ducts be irritated?
liver cirrhosis
What are the injury markers for obstructed bile ducts?
ALP and GGT
What can acute pancreatitis be do to?
heavy alcohol intake (40%)
Gallstone blockage (40%)
What would lead to chronic pancreatitis?
- CF
- hyperlipidemia
- years of ethanol abuse
What is increased in patients when they have acute pancreatitis?
They have increased levels of alpha-amylase and pancreatic lipase
How can determine if Acute pancreatitis is due to ethanol?
serum lipase/amylase ratio is greater than 2
How to determine if acute pancreatitis is due to gallstones?
increase in serum amylase, lipase, ALP, and GGT
What are potential diagnoses if a patient has an abnormal increase in alkaline phosphatase?
paget disease or bone tumor
What does an increase in alpha-fetoprotein (AFP) indicate in an adult?
liver cancer
