Enzymology, lipid, cardiac biomarkers

Question 1

What are “leakage enzymes” ?

Answer 1

May be in cytosol, organelles, or both

Enzymes escape from the cell as a result of injury to cell membranes or organelles

Question 2

What are “induced enzymes”?

Answer 2

Usually attached to membranes, rarely due to cell injury

Increased are usually due to increased production

Question 3

What are the liver leakage enzymes?

Answer 3

ALT
AST
SDH (large animal)
GLDH (large animal)

Question 4

What are induced enzymes associated with the liver?

Answer 4

ALP and GGT

Question 5

T/F: serum ALT will be increased more with sublethal damage then it is with necrosis

Answer 5

True

Question 6

What enzyme is muscle specific, an increase indicates damage to muscular tissue

Answer 6

Creatine kinase (CK)

Question 7

Asparatate aminotransferase has the highest activity in what organs?

Answer 7

Skeletal and cardiac muscle

Hepatocytes

Question 8

What is the half life of creatinine kinase (CK)?

Answer 8

Rapidly peaks in 6-12hrs following injury and has a half life of 2-4hrs

Question 9

Is AST a good indicator of muscle injury?

Answer 9

Can be

Creatinine kinase is muscle specific but has a very short half life. AST stays elevated longer in muscle injury, but is not muscle specific

Question 10

_________ is a liver specific enzyme in dogs and cats but can be incresed with severe muscle damage

Answer 10

ALT

Question 11

__________ is released from dead/dying muscle. It is not protein bound in the blood and is excreted in the urine

Answer 11

Myoglobin

Question 12

Dipstick positive for blood/hemoglobin. How can you distinguish myoglobin from hemoglobin in the urine?

Answer 12

Ammonium sulfate precipitation test
-hemoglobin precipitates, myoglobin does not

Anemia -> hemoglobin

CK increased -> myoglobin

Question 13

Triglycerides synthesized in the liver are not water soluble and must be attached to proteins in the blood

Answer 13

Very low density lipoprotein (VLDL)

Question 14

What are the uses of cholesterol?

Answer 14

Produce steroid hormones

Component of cell membranes

Precursor to bile acids

Question 15

What are the most commonly measured blood lipids?

Answer 15

Triglyceride and cholesterol

Question 16

A primary hyperlipidemia is due to ?

Answer 16

Inherited disorder

Question 17

Secondary hyperlipidemia is associated with ??

Answer 17

Endocrine or metabolic disorders

Question 18

T/F: hyperlipidemia always results in lipemia

Answer 18

False

Hyperlipidemia -> trigyclerides and cholesterol

Lipemia–> chylomicroins or VLDL

Question 19

What do you see commonly in small equids during starvation or chronic illness secondary to negative energy balance?

Answer 19

Equine hyperlipidemia

Question 20

What are primary hyperlipidemia ? What breed of dogs is this seen most frequently?

Answer 20

Inherited defect in lipoprotein lipase or apoprotein CII

Miniature schnauzers

Question 21

What diseases are associated with secondary hyperlipidemia?

Answer 21

Hypothyroidism 
Diabetes mellitus 
Hyperadrenocorticism 
Pancreatitis 
Hepatic disease 
Nephrotic syndrome

Question 22

What is nephrotic syndrome?

Answer 22

Hypercholesterolemia is a common finding in dogs and cats with protein losing glomerulonephropathy

• hypoalbuminemia
• proteinuria
• hypercholesterolemia
• edema or ascities

Question 23

What can cause a hypolipidemia?

Answer 23

Liver failure - hypocholesterolemia

Maldigestion/malabsorption

Protein losing enteropathy

Starvation

Question 24

During starvation, ________ can occur due to fat mobilization from adipose tissue exceeding the ability of the liver to oxidase the fat

Answer 24

Ketosis

Question 25

Lactating dairy cows, anorexic obese cats, and anorexic small equids can have ______________ because of increased hepatic uptake of LCFA plus impaired hepatic synthesis of triglyceride rich lipoproteins

Answer 25

Hepatic lipidosis

Question 26

What are the two main tests for cardiac function/damage

Answer 26

Myocardial cell injury test - leakage markers

Specific cardiac function proteins - functional markers

Question 27

Cardiac biomarkers should have what prerequisites?

Answer 27

Quick turn around time
High sensitivity and specificity for cardiac injury
Affordable
Screening test for asymptomatic heart disease
Distinguish cardiac vs non cardiac dyspena
Identify myocardial injury

Question 28

Troponin complex regulates??

Answer 28

Calcium-mediated interaction of myosin and actin

Question 29

The tropnonin complex in made up of what 3 proteins ?

Answer 29

Cardiac troponin I
Cardiac troponin T
Cardiac troponin C

Question 30

What one of the troponin proteins is inhibitory and prevents contraction when calcium is not present and is the most diagnostically useful?

Answer 30

Troponin I

Question 31

Increasing troponin concentrations suggest?

Answer 31

Worsening condition of the heart

Eg congestive heart failure, pericardial disease, or cardiac injury due to sepsis, doxorubicin toxicity, gastric-dilatation-volvulus, and myocarditis

Question 32

What is the most useful functional marker for the heart

Answer 32

Natriuretic peptide (hormone regulating salt and water homeostatis and BP control )

Question 33

Brain natriuretic peptide is produced by the ________

Answer 33

Ventricles

Question 34

What is increased in production with increased ventricular wall tension hypertrophy, or myocardial dysfunction

Answer 34

Brain natriuretic peptide (BNP)

Cleaved to pro-BNP where the N terminal is cleaved

N-Terminal has a long halflife and what is measured

Question 35

Under what conditions can plasma NT-proBNP be increased?

Answer 35

Ventricular hypertrophy 
Tachycardia 
Hypoxia 
Expanded fluid volume 
Reduced renal clearance of the peptide