Lecture 24

Question 1

What are isozymes?

Answer 1

catalyze the same biochemical reaction and the same enzyme has multiple forms

can be used as an injury marker

Question 2

What is the reaction creatine kinase catalyzes?

Answer 2

At high ATP levels creatine phosphate (CrP) is formed

At high CrP levels, ATP is formed using the CrP

Question 3

What are the three isozymes of creatine kinase?

Answer 3

1. CK-BB (CK-1)
2. CK-MB (CK-2)
3. CK-MM (CK-3)

Question 4

What form of creatine kinase is most present in the brain?

Answer 4

CK-BB or CK-1

Question 5

When are CK-BB or CK-1 levels increased in the body?

Answer 5

Elevated after CNS damage

Question 6

What are the forms of creatine kinase found in the heart and in what percentages are they present?

Answer 6

CK-MB (30%)

CK-MM (70%)

Question 7

When are are CK-MB and CK-MM levels elevated in the body?

Answer 7

After a MI

Question 8

What isozymes are found in skeletal muscle, in regards to creatine kinase?

Answer 8

98% is CK-MM

2% is CK-MB

Question 9

When would serum CK-MM levels be elevated in the body?

Answer 9

this may be seen in patients with rhabdomyolysis and/or muscular dystrophy

Question 10

How can hemolytic anemia be tested?

Answer 10

the severity of hemolytic anemia can be measured by the increase of LDH in the serum following RBC damage

Question 11

What forms of LDH are elevated after an MI?

Answer 11

An increase in LDH-1 and LDH-2 isozymes in the blood

Question 12

Explain the time frame for MI markers?

Answer 12

CK-MB levels will peak after 24 hours and then LDH levels will peak after 48 hours

Question 13

What are the criteria for indication of an MI?

Answer 13

A. the CK-MB/total CK ratio is greater than 6 percent

B. The ratio is greater than 3 percent and troponins are increased

Question 14

What are the purpose of troponins?

Answer 14

They are involved with muscle contraction

Question 15

What isozymes of troponin are measured as heart injury markers?

Answer 15

Cardiac troponin I (cTnI) - inhibition of actomyosin

Cardiac troponin T (cTnT) - tropomyosin binding

Question 16

In order to be diagnosed with MI, what must must be accumulated in the blood?

Answer 16

1. increase in cardiac troponins (cTnI or cTnT)

2. increase in CK-MB

Question 17

What method is used to measure MI injury markers?

Answer 17

ELISA

Question 18

What are the liver function test examples?

Answer 18

1. ammonium would be high
2. albumin would be reduced
3. bilirubin would be high

Question 19

What can be used to determine liver membrane integrity?

Answer 19

1. ALT (alanine aminotransferase)

2. AST (aspartate aminotransferase)

Question 20

What does a high ALT to AST ratio indicate?

Answer 20

hepatic viral infection

Question 21

What does a high AST to ALT ratio indicate?

Answer 21

hepatic alcohol damage

Question 22

What can extra-hepatic bile ducts be obstructed by?

Answer 22

Gallstones or tumors

Question 23

How can intra-hepatic ducts be irritated?

Answer 23

liver cirrhosis

Question 24

What are the injury markers for obstructed bile ducts?

Answer 24

ALP and GGT

Question 25

What can acute pancreatitis be do to?

Answer 25

heavy alcohol intake (40%)

Gallstone blockage (40%)

Question 26

What would lead to chronic pancreatitis?

Answer 26

1. CF
2. hyperlipidemia
3. years of ethanol abuse

Question 27

What is increased in patients when they have acute pancreatitis?

Answer 27

They have increased levels of alpha-amylase and pancreatic lipase

Question 28

How can determine if Acute pancreatitis is due to ethanol?

Answer 28

serum lipase/amylase ratio is greater than 2

Question 29

How to determine if acute pancreatitis is due to gallstones?

Answer 29

increase in serum amylase, lipase, ALP, and GGT

Question 30

What are potential diagnoses if a patient has an abnormal increase in alkaline phosphatase?

Answer 30

paget disease or bone tumor

Question 31

What does an increase in alpha-fetoprotein (AFP) indicate in an adult?

Answer 31

liver cancer