Clinical Significance of Enzymes

Question 1

Pertinent findings in Case study

of 51 y.o JK

Answer 1

• overweight
• history of AMI and T2DM
• abdominal discomfort
• body malaise and bilateral throbbing headache

Question 2

Enzyme that plays a role in energy production; ATP regeneration

Answer 2

Creatine Kinase

Question 3

storage of high energy Creatine phosphate

Answer 3

Creatine Kinase

Question 4

In contraction cycle, Creatine Phosphate use the production of ATP with?

Answer 4

relative constant level of muscle ATP

Question 5

Creatine + ATP =

Answer 5

Creatine Phospate + ADP

Question 6

Creatine Kinase has highest activity in?

Answer 6

Skeletal muscle, heart muscle and brain tissue

Question 7

Myocardial Infarction, Muscle dystrophy and Rhabdomyolysis

Answer 7

Creatine Kinase

Question 8

Creatine Kinase is considered a sensitive indicator of

Answer 8

AMI; Muscular Dystrophy (Duchenne)

Question 9

CK isoforms

Answer 9

CK-MM (muscle); CK-MB (hybrid); CK-BB (brain)

Question 10

20% CK activity is

Answer 10

CK-MB

Question 11

Highest concentration of CK-BB is found

Answer 11

CNS (brain), GIT and uterus during pregnancyn akso urinary bladder, lungs, prostate, colon, stomach, and thyroid

Question 12

What is the only tissue from which CK-MB enters the serum in significant quantities?

Answer 12

Myocardium

Question 13

Which is more clinically significant isoform of CK?Why?

Answer 13

CK-MB isoenzyme - elevated levels come from cardiac tissue (CK- MM can also be found in skeletal muscle so less specific)

Question 14

Percent that is a good indicator if myocardial damage

Answer 14

Greater or equal to 6%

Question 15

Methods use for measurement in CK? (Clue: E.I.R.I)

Answer 15

Electrophoresis, Ion exchange chroma, radioimmunoassay, immunoinhibition methods

Question 16

Can detech unsatisfactory separation and allows visualization of Adenylate Kinase

Answer 16

Electrophoresis in CK

Question 17

Released from RBCs in hemolyzed samples and causes falsely elevated CK or CK MB

Answer 17

Adenylate Kinase

Question 18

Sources of error in CK

Answer 18

Hemolysis, Light, Bedridden, Athletes

Question 19

True or false: serum should be stored in a dark place because CK is inactivated by light (leading to falsely decreased values)

Answer 19

True

Question 20

Total CK in Makes and Females

Answer 20

M: 46 to 171 U/L (0.8 to 2.9 ukat/L)
F: 34 to 145 U/L (0.6 to 2.4 ukat/L)

Question 21

Catalyzes the interconversion of lactic and pyruvic acids

Answer 21

Lactate dehydrogenase

Question 22

Lesser amounts of LD are found in

Answer 22

Lung,smooth muscle and brain

Question 23

Acts as a Hydrogen donor

Answer 23

NAD+ (Nicotinamide adenine dinucleotide)

Question 24

Diseases with highest levels of (total) LDH

Answer 24

Pernicious anemia, hemolytic disorders

Question 25

Which enzyme can be used as a cardiac biomarker?

Answer 25

LDH

Question 26

For LDH, AST, CK and Troponin I, which is a reliable cardiac biomarker of choice in AMI?

Answer 26

Troponin I

Question 27

Which of the isoenzymes in LDH migrates most quickly toward anode in electrophoresis?

Answer 27

LD-1(HHHH)

Question 28

LD Flipped Pattern

Answer 28

In necrosis and IV hemolysis, serum levels of LD-1 increase (greater than LD-2)

Question 29

About LD-6

Answer 29

-migrates cathodic to LD-5 -alcoholic dehydrogenase -patients w/ arteriosclerotic vascular failure

Question 30

Hepatic clngestion due to cardiovascular disease

Answer 30

LD-5

Question 31

Liver injury secondary to severe circulatory insufficiency

Answer 31

LD-6

Question 32

Erythrocytes contain LDH approx.

Answer 32

100-150x in serum

Question 33

LDH activity is _____ in serum regardless of storage temp

Answer 33

Unstable

Question 34

Most labile isoenzyme in LDH

Answer 34

LD-5

Question 35

Reference range of LDH

Answer 35

125-220 U/L

Question 36

Commonly referred to as a transaminase (transfer of an amino group between aspartate and a-keto acids woth the for ation of oxaloaxetate and glutamate)

Answer 36

AST

Question 37

End products of Aspartate and A-keto-glutarate

Answer 37

Oxaloacetate and Glutamate

Question 38

Keto Acids formed by the reaction are ultimately oxidized by the _______ cycle to provide a source of energy (in AST)

Answer 38

Tricarboxylic Acid (TCA) Cycle

Question 39

AST elevations are frequently seen in

Answer 39

Pulmonary embolism

Question 40

In liver infection like viral hepatitis: levels may reach

Answer 40

100x the ULN

Question 41

In cirrhosis: moderate levels approx

Answer 41

4x the ULN

Question 42

AST activity is ____ in serum for 3-4 days at ref temp

Answer 42

Stable

Question 43

Reference range of AST

Answer 43

5-35 U/L (0.1-0.6 ukat/L)

Question 44

Old name of Alanine Aminotrasnferase

Answer 44

Glutamic Pyruvic Transaminase (SGPT)

Question 45

Which is a more liver specific enzyme?

Answer 45

ALT

Question 46

Half life of AST and ALT in serum

Answer 46

AST: 16 HOURS ALT: 24 HOURS (elevated levels remain longer)

Question 47

Which liver enzyme is relatively unaffected by hemolysis?

Answer 47

ALT

Question 48

Activator used in Alkaline Phosphatase

Answer 48

MG+2

Question 49

In ALP, highest concentration is found in the liver in both

Answer 49

Sinusoidal, and bile canalicular membranes

Question 50

ALP measurement is used in the evaluation of

Answer 50

Hepatobiliary and bone disorders

Question 51

Lithiasis

Answer 51

Gallstones

Question 52

Impaired or absent flow of bile to the biliary tract, stagnant bile accumulate in the duct causing congestion and eventual damage to the cells

Answer 52

Cholestasis

Question 53

Which disease has the highest elevation of ALP?

Answer 53

Paget’s disease (osteititis deformans)

Question 54

Hypersecretion of parathryroid hormone that stimulates the osteoclasts in bone

Answer 54

Hyperparathyroidism

Question 55

Responsible for bone resorption

Answer 55

Osteoclast

Question 56

Descending order of electrophoresis fraction migration

Answer 56

Liver - bone - placental - intestinal

Question 57

ALP is approximately 6x more concentrated in ____ than in _____

Answer 57

Erythrocytes, serum

Question 58

Optimal pH of ACP reaction

Answer 58

5.0

Question 59

Richest source of ACP

Answer 59

Prostate

Question 60

Decrease activity of ACP is due to the

Answer 60

Loss of carbon dioxide from serum (resultant increase in pH)

Question 61

Y-glutamyl donor

Answer 61

Glutathione

Question 62

Higher elevations of GGT is generally observed in

Answer 62

Biliary duct obstruction

Question 63

In hepatic parenchyma: GGT exists in

Answer 63

Smooth ER

Question 64

GGT levels will be increased in patient receiving enzyme-inducing drugs

Answer 64

Warfarin, Phenobarbitol, and Phenytoin

Question 65

Hemolysis does not interfere with GGT levels because the enzyme is lacking _____

Answer 65

Erythrocytes

Question 66

Starch is made up of

Answer 66

Amylose and amylopectin

Question 67

Alpha-Amylase attacks only

Answer 67

Alpha-glycosidic bonds

Question 68

Ontermediate chains which contain alpha-1,6 branching linkages

Answer 68

Dextrins

Question 69

Amylase requires ____ and ___ for its activation

Answer 69

Calcium and chloride

Question 70

Major tissue sources of serum amylase

Answer 70

1. Acinar cells of pancrease 2 Salivary glands

Question 71

Macroamylasemia

Answer 71

Amylase molecule combines with immunoglobulins to form a too large complex to be filtered across the glomerulus

Question 72

Effect of morphine and other opiated for Ain relief before blood sampling in serum amylase

Answer 72

Falsely elevated

Question 73

Sphincter of Oddi

Answer 73

Muscular opening which leads to the duodenum of small intestine

Question 74

An enzyme that hydrolyzes the ester linkages of fats to produce alcohols and fatty acids

Answer 74

Lipase

Question 75

Lipase concentration is found primarily in the

Answer 75

Pancreas

Question 76

Preferred enzyme in diagnosing acute pancreatitis

Answer 76

Lipase