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57 Cards in this Set
- Front
- Back
What is the difference between intra and extracellular enzymes?
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Intracellular = inside organs/cells, have no function in plasma.
Extracellular = function in plasma. |
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What is the diagnostic level of extracellular enzymes?
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When plasma level is decreased; they should normally be measurable in the plasma.
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What are the 2 types of intracellular enzymes?
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1. Secreted
2. Metabolic |
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What are the diagnostic levels of secreted enzymes?
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Increased - when mode of secretion (excretion) is blocked
OR Decreased - when tissue is damaged. |
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What are the diagnostic levels of metabolic enzymes?
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Increase - shows that cell damage has occured.
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Give 4 examples of Enzymes of secretion:
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1. Amylase
2. Lipase 3. Acid phosphatase 4. Alkaline phosphatase |
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Give 4 examples of Metabolic enzymes:
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1. CK
2. LD 3. AST 4. ALT |
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Where are EXTRACELLULAR enzymes made?
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In the liver
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What are examples of extracellular enzymes?
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Blood coagulation enzymes
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Give 2 examples of enzymes that are tumor markers:
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PAP and CK
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What would be the diagnostic level of enzymes as tumor markers?
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Increased - from tumor growth.
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What is the tissue source of LD1?
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Heart and RBCs
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What is the tissue source of LD2?
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Renal
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What is the tissue source of LD3?
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Lung, spleen and pancreas
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What is the tissue source of LD4 and LD5?
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Liver and skeletal muscle
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What are 5 analytical methods for measuring isoenzymes?
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1. Ion exchange chromatography
2. Immunoinhibition 3. RIA 4. Heat fractionation 5. Electrophoresis |
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What type of enzyme is LD?
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Oxidoreductase
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What 2 preanalytic variables alter LD measurement?
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-Gross hemolysis
-Temp of storage - should be 25C or less. |
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How is LD activity measured?
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By monitoring absorbance at 340 nm via oxidoreduction of NADH - but the ref ranges are different depending on direction of reaction.
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In what 5 diseases are LD levels clinically significant? What isotypes in each disease?
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Heart disease - LD1>LD2 (flip)
Anemia: Increased LD1 Pulmonary: Increased LD3 Malignancy: Increased LD3 Liver: increased LD4/LD5 |
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What does a normal LD electrophoresis show for levels?
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2>1>3>4>5
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What effect does MI (heart dis) have on LD electrophoresis?
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1>2>3>4>5 --- LD flip
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What is a faster way to measure LD-1 than the time consuming electrophoresis?
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Antibody against M-subunit precipitates all but LD1
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What type of enzyme is CREATININE KINASE?
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Transferase
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What method is used for measuring CK on automated analyzers?
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Reaction inhibition
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What preanalytic variables must be controlled for CK samples?
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1. Hemolysis
2. Store in dark or CK levels will decrease |
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What are the 3 isotypes of CK?
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1. CK-MM
2. CK-MB 3. CK-BB |
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What tissue is each CK isotype specific for?
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CKMM = Mostly Muscle
CKMB = Heart and Muscle CKBB = Brain, bladder, etc. |
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Which CK isotype is elevated in:
-Myocardial infarct? -Brain damage/tumor? -Injections/exercise/injury? |
Injections/injury = CK-MM
MI = CK-MB Brain dmg = CK-BB |
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What are ALT/AST clinical markers of?
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Liver disorders
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Generally which is higher in hepatic damage, AST or ALT?
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ALT is usually higher than AST.
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What does AST >> ALT indicate?
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Poor prognosis and massive cell necrosis.
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What can alter ALT and AST measurements?
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hemolysis
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what type of enzymes are ALT and AST?
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Transferases
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What type of enzyme is ALP?
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hydrolase
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What are 3 preanalytic variables of ALP measurement?
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-Needs pH of 10-12
-Needs Mg2+ -hemolysis greatly increases levels falsely |
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What is the clinical significance of ALP measurement?
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Bone and Liver
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What type of liver disease does increased ALP indicate?
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Biliary tract obstruction
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What is the clinical significance of 5' Nucleotidase?
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Liver: Increased in hepatobiliary disorders
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What is the clinical significance of GGT?
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Liver - ALCOHOLISM
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What 3 enzymes are clinically significant indicators of Pancreatic disease?
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Amylase, Lipase, and Aldolase
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What is the clinical significance of ACP?
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(acid phosphatase)
-Can be used to detect prostate cancer that is metastesized (but the PSA is better method now). |
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What is the clinical significance of Cholinesterase?
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Used as an indicator of poisoning with anesthesia or organic pesticides.
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What are important Cardiac markers? Which is elevated first after MI?
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1. Myoglobin (first)
2. Troponin (more sensitive) 3. CK-MB |
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What enzyme will not be affected by hemolysis?
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GGT - it is NOT in RBCs
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Regarding ALP, where are each isoform found? (1, 2, 3)
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ALP1 = liver
ALP2 = bone ALP3 = intestine |
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How can ALP1 and 2 be seperated?
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Liver lives, bone burns - susceptible to heat denaturation
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How can 5-nucleotidase aid in ruling out liver disease?
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If ALP is increased but 5-nucleotidase is normal, then you could suspect bone disease. To confirm, run an AST.
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What type of liver disease would 5-nucleotidase be elevated in?
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hepatobiliary disease
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What type of enzyme is 5-nucleotidase?
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hydrolase, like ALP
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So what are all the hydrolases?
(7) |
-ALP/ACP
-5'nucleotidase -Amylase/lipase -Cholinesterase -Aldolase |
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which enzyme will NOT be affected by hemolysis?
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GGT
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Which enzymes can aid in differentiating ALP bone from liver disease?
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5-nucleotidase
GGT |
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GGT is more specific for ___ than for ___
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Alcoholism than for cirrhosis
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which enzymes are specific for pancreas?
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Amylase, Lipase, Aldolase
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Which enzyme is specific for prostate?
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Acid phosphatase - ACP
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Which pancreatic enzyme remains elevated longer?
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Lipase longer than amylase
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