2. Enzyme and Serum
Enzymes –Complex protein catalysts, found in small amounts,
cause specific chemical change in all parts of the body. Present in
all parts of the body including: blood, intestinal fluids, mouth
(saliva),stomach (gastric juice).
-Normally only small quantities of intracellular enzymes leak
from cells into blood or other body fluids.
Serum- is the component that is neither a blood cell (serum
does not contain white or red blood cells) nor a clotting factor; it
is the blood plasma with the fibrinogens removed. Serum
includes all proteins not used in blood clotting (coagulation) and
all the electrolytes, antibodies, antigens and hormones.
3.
4. Sources of non-functional enzymes
•Cell damage
•Obstruction of normal pathways: eg obstruction of bile
duct increases alkaline phosphatase
•Increase of the enzyme synthesis: eg Bilirubin increases
the rate of synthesis of alkaline phosphatase in obstructive
liver disease.
•Increased permeability: eg hypoxia.
5. Medical importance of Non-functional
enzymes
Measurement of these enzymes is important for:
•Diagnosis of diseases- as disease of different organs
cause elevation of different plasma enzymes.
•Prognosis of the disease- Follow up treatment pre and
post measurement of enzymes
8. A heart attack -blood flow to a part of your heart is blocked ,part of the
heart muscle is damaged or dies. The medical term for this is Myocardial
infarction.
SYMPTOMS
• Chest pain- Pain restricted or may move from chest to your arms, shoulder,
neck, teeth, jaw, belly area , back.
Pain usually lasts longer than 20 minutes.
Other symptoms-
• Anxiety
• Cough
• Fainting
• Light-headedness, dizziness
• Nausea or vomiting
• Palpitations (feeling like your heart is beating too fast or irregularly)
• Shortness of breath
• Sweating (which may be very heavy)
9. CAUSES:
• Blood clot that blocks one of
the coronary arteries. The
coronary arteries bring blood
and oxygen to the heart. If the
blood flow is blocked, the
heart is starved of oxygen and
heart cells die.
• Plaque-A hard substance can
build up in the walls of your
coronary arteries. This plaque
is made up of cholesterol and
other cells.
10. • The most common cause of blocked arteries is atherosclerosis. Exact cause of
atherosclerosis is unknown, but most researchers believe it begins with an injury
to the innermost layer of the artery, known as the endothelium.
The following factors are thought to contribute to the damage:
• High blood pressure
• Elevated LDL ("bad") cholesterol
• An accumulation of homocysteine (amino acid produced by the human body,
thought to be a risk factor for heart disease, stroke, osteoporosis, diabetes, and
dementia)
• Smoking
• Diabetes
• Inflammation
11. • This is a normal coronary
artery with a nice, big,
unobstructed lumen for
supplying plenty of blood
to the myocardium.
• At the left the lumen is
about 50% occluded. At the
right, there has been
thrombosis with
organization and
recanalization to leave
three small remaining
lumens.
12. • This coronary artery
demonstrates yellowish
atherosclerotic plaques
grossly.
• Coronary artery opened
longitudinally demonstrates
severe atherosclerosis.
14. TESTS
1.Troponin test
• Composed of three regulatory proteins (troponin C, I and T)
• Attached to tropomyosin ,found in the grooves between actin
filaments in muscle tissue.
• Found in skeletal and cardiac muscle but not smooth muscle.
• Troponin I and T- Excellent markers for myocardial infarction
• Serum levels of troponin I rise within 4-8 hrs after the onset of
chest pains ,levels peak within 12-16 hrs ,return to baseline within
5-9 days.
• Measurement of serum LDH fractions was once considered the
ideal marker for onset and severity of a heart attack, the high
specificity of troponin I to heart muscle necrosis make this protein
the preferred marker to measure in patients suspected of suffering
a myocardial infarct.
15. • Normal Values
• Cardiac troponin levels are normally so low they cannot be detected with
most blood tests.
• The test results are usually considered normal if the results are:
• Troponin I : less than 10 μg/L
• Troponin T : 0–0.1 μg/L
• Normal troponin levels 12 hours after chest pain has started mean a heart
attack is unlikely.
• What abnormal results mean
• Even a slight increase, usually means there has been some damage to the
heart. Significantly high levels of troponin are a sign that a heart attack has
occurred.
• Most patients who have had a heart attack have increased troponin levels
within 6 hours. After 12 hours almost everyone who has had a heart attack
will have raised levels.
• Troponin levels may remain high for 1 to 2 weeks after a heart attack.
16. Increased troponin levels may also be due to:
• Abnormally fast heart beat
• High blood pressure in lung arteries (pulmonary hypertension)
• Blockage of a lung artery by a blood clot, fat, or tumor cells (pulmonary
embolus)
• Congestive heart failure
• Inflammation of the heart muscle usually due to a virus (myocarditis)
• Strenuous exercise (for example, due to marathons)
• Trauma that injures the heart such as a car accident
• Weakening of the heart muscle (cardiomyopathy)
• Cardiac angioplasty/stenting
• Purposeful shocking of the heart by medical personnel
• Open heart surgery
17. 2.Creatine Kinase (CK)/Creatine Phosphokinase (CPK)
• Creatine Creatine Phosphate
ATP ADP
(Energy source for muscle contraction)
• Dimer (consists of 2 protomers)-B (after brain) and M (after Muscle).
• 3 Tissue specific isoenzymes:
• CPK1 (CPK-BB) is the characteristic isoenzyme in brain and is in
significant amounts in smooth muscle and is 0% of the normal serum total.
• **It increases in brain tumors.
• CPK2 (CPK-MB) accounts for about 35% of the CPK activity in cardiac
muscle , but less than 5% in skeletal muscle and is 0% of the normal serum
total.
• **It increases in heart diseases.
18. • CPK3 (CPK-MM) is the predominant isoenzyme in muscle
and is 100% of the normal serum total.
• **It increases in skeletal muscle diseases
• Found in heart, skeletal muscle, brain.
• Level of CPK rises within 6hrs and peak by ~18hrs.
• If not persistent, normal within 2-3 days.
• CPK-MB levels rise 3-6 hrs after a myocardial infarction
and peak 12-24 hrs later, returns to normal 12-48 hrs after
the infarct.
19. • Normal Values:
male: 5-35 ug/ml (mcg/ml);
female: 5-25 ug/ml
newborn: 10-300 IU/L
• Precautions:
• Draw the sample before giving or one hour after giving I.M.
injections. I.M. injections will increase the total CK level.
• Obtain the blood samples on schedule. Always note the time
the sample was drawn and the hours elapsed since onset of
chest pain.
• Be sure to handle the sample gently to prevent hemolysis.
Always have the sample transported to the lab promptly
because CK activity diminishes significantly after 2 hours at
room temperature.
20. 3.Lactate dehydrogenase(LDH)
Lactic acid Pyruvic acid
NAD NADH+H
• LDH is a tetramer(consists of 4 protomers)-H(after heart) and M(after
muscle)
• LDH has 5 isoenzymes:-
• LD1 and LD2 -heart, red blood cells and kidneys.
• LD3 –lungs
• LD4 and LD5 -liver, skin, and skeletal muscles.
• LDH elevates in 24-48 hours and peaks in 48-72 hours after the episode.
• Narcotic drugs and IM injections can elevate serum LDH levels. Hemolysis
of the blood can cause an elevated LDH because LDH is plentiful in the
erythrocytes.
• Because many common diseases increase total LDH (LD) levels, isoenzyme
electrophoresis is usually necessary for diagnosis
21. 4.SGOT
• Serum Glutamic Oxaloacetic Transaminase called: AST, (Aspartate
Aminotransferase) (is released with tissue necrosis).
• Aspartate (Asp) + α-ketoglutarate ↔ oxaloacetate + glutamate (Glu)
• Is an important enzyme in amino acid metabolism.
• AST is found in the liver, heart, skeletal muscle, kidneys, brain and red blood cells.
• Normal Values: 5-40 U/ml (Frankel) 4-36 IU/L; or 16-60 (Karmen) U/ml U/L
at 30 degrees C; or 8-33 (SI units) at 37 degrees C.
• Clinical Implications:
• Elevation 8-12 hours after infarction. Peak levels are reached 24-48 hours
after the MI.
• This enzyme is not particularly indicative of an MI. Other conditions can also
cause a rise in the levels. High levels of SGOT may be obtained with trauma to
the skeletal muscles, in liver disease, pancreatitis and others.
• *Decreased levels of enzyme are found in pregnancy, diabetes, beriberi.
Elevations can be caused by hepatitis, trauma, musculoskeletal disease, IM
injection, pancreatitis, liver cancer, and strenuous exercise.
22. 5. SGPT
• Serum Glutamic Pyruvic Transaminase- enzyme is called Alanine
Transaminase (ALT)
• α-ketoglutarate + L-alanine ⇌ L-glutamate + pyruvate
• ALT is particularly diagnostic of liver involvement as this enzyme is found
predominantly in hepatocytes.
• Elevated levels of ALT (SGPT) = viral hepatitis, diabetes, congestive heart
failure, liver damage, bile duct problems or myopathy.
• ALT is commonly used as a way of screening for liver problems.
• Elevated ALT may also be caused by dietary choline deficiency.
• Fluctuation of ALT levels is normal over the course of the day, and ALT
levels can also increase in response to strenuous physical exercise.
23. • Normally in liver disease or damage that is not of viral origin the ratio of
ALT/AST is less than1.
• With viral hepatitis the ALT/AST ratio will be greater than1.
• level of AST elevation in the serum =number of cells involved
• Following injury, levels of AST rise within 8 hours and peak 24–36 hours
later. Within 3–7 days the level of AST should return to pre-injury levels
unless further injury occurs.
* Although measurement of AST is not, in and of itself, diagnostic for
myocardial infarction, taken together with LDH and CK measurements the
level of AST is useful for timing of the infarct
24. • Preventive Care: You can reduce your risk of heart attack by:
• Quit smoking.
• Aerobic exercise (such as walking, biking, or swimming) for at least 30
minutes 5 days per week.
• Reducing stress and learning stress-reduction techniques such as deep
breathing and meditation.
• Eating a diet low in saturated fat and rich in fruits, vegetables, and whole
grains.
• Losing weight or maintaining a proper weight.
• Follow your doctor’s instructions to keep these risk factors under control.
• Treatment Approach:
• The goal when treating a heart attack is to restore blood flow to the
affected area of the heart immediately, to preserve as much heart muscle
and heart function as possible. If your doctor has prescribed nitroglycerin,
take it while you are waiting for emergency medical personnel to arrive.
25. • Medications
• When you arrive at the hospital, you will likely be given one or more
medications to help your body cope with, or ward off, damage from the
heart attack, including:
• Aspirin -- helps stop blood from clotting. You may be given aspirin in the
ambulance or as soon as you get to the hospital. Aspirin should be
continued indefinitely at a dose of 81 mg per day.
• Nitroglycerin -- helps dilate (widen) blood vessels. You may be given
nitroglycerin in the ambulance or as soon as you get to the hospital.
• Pain reliever -- helps relieve pain and is often given intravenously (IV).
• Thrombolytic -- work to break up clots. They are most effective when
taken within 2 hours of the heart attack, and are not given after 12 hours
have elapsed. These drugs may be given with other anticoagulants (blood
thinners).
• Anticoagulants (blood thinners) -- make your blood less likely to form
clots. Heparin is often given by injection while you are in the hospital.
26. • The prostate gland, which is
associated with the
production of sperm in men,
secretes an enzyme called
prostatic acid phosphatase
(PAP). In all stages of
prostate cancer, except the
final stages, PAP levels are
raised compared to those of
healthy individuals.
27. ACID PHOSPHATASE
• Hydrolase enzyme -catalyze the hydrolysis of a chemical bond.
Specifically, it targets and breaks the molecular bonds of phosphate groups.
• ACP can be found in certain organs and tissues, including blood cells, bone
marrow, the spleen, pancreas, liver and kidneys.
• Found in the greatest concentration in the prostate and up to 1,000
times greater in seminal fluid than any other bodily fluid.
• The latter fact is useful in forensics since the detection of prostatic acid
phosphatase (PAP) in vaginal tissue measuring levels greater than 3 U/ML
(units per milliliter) is used as supporting evidence that a rape has
occurred.
• It is stored in lysosomes and functions when these fuse with endosomes,
which are acidified while they function; therefore, it has an acidic pH.
• Normal Value:
0 to 1.1 Bodanzky units/ml;
1 to 4 King-Armstrong units/ml;
0.13 to 0.63 BLB units/ml.
28. • Clinical Implications:
• Appears primarily in the prostate gland and semen. It is also found
in other organs, but in very small amounts. Prostatic and
erythrocytic enzymes are the two major isoenzymes.
• The prostatic isoenzyme is more specific for prostatic cancer.
widespread the tumor=produce high serum acid phosphatase
levels.
• Marked increased acid phosphatase levels: A tumor that has
spread beyond the prostatic capsule
• Moderately increased acid phosphatase levels: Prostatic
infarction, Paget's disease, Gaucher's disease, multiple myeloma
• Declining high acid phosphatase levels: Successful treatment of
prostatic cancer
• Hemolysis due to rough handling of sample or improper storage
may interfere with test results.
• Acid phosphatase levels drop by 50% within one hour if the sample
stays at room temperature without the addition of a preservative or
if it is not packed in ice.
29. • Abnormal levels may indicate the presence of systemic
infection, anemia, hepatitis.
• Elevated levels of PAP in particular is associated
with inflammation of the prostate, as well as prostate
cancer that has metastasized to the bone.
• Phosphatase testing is also used to assess enzymatic damage
caused by kidney disease, liver disease, or a heart attack.
• The blood sample is exposed to one of several agents to elicit
an enzymatic reaction, namely 4-aminoantipyrine, or a
solution of disodium phenyl phosphate and citrate.
• To measure levels of PAP, tartrate is used. By observing the
reaction with these different agents, the clinician is able to
determine which tissue is releasing phosphatase enzymes
into the bloodstream and what type they are. Usually, the test
results are available within one to two days.
30. • The diagnostic precision of plasma enzyme analysis may be improved
by:
• 1. Estimation of more than one- For instance, although both alanine and
aspartate transaminases are abundant in the liver, the concentration of
aspartate transaminase is much greater than that of alanine transaminase in
heart muscle
• 2. Isoenzyme determination- Some enzymes exist in more than one form:
these isoenzymes may be separated by their different physical or chemical
properties. For example, creatine kinase may be derived from skeletal or
cardiac muscle, but one of its isoenzymes is found predominantly in the
myocardium
• 3. Serial enzyme estimations- The rate of change of plasma enzyme
activity is related to a balance between the rate of entry and the rate of
removal from the circulation. A persistently raised plasma enzyme activity is
suggestive of a chronic disorder or occasionally of impaired clearance.
31. • Factors Affecting Results of Plasma Enzyme Assays
1. Analytical factors affecting results:
• The total concentration of all plasma enzyme proteins is less than 1 g/L.
Results of enzyme assays are not usually expressed as concentrations, but
as activities.
• The results of such measurements depend on many factors. These include
the concentrations of the substrate and product, the pH and
temperature at which the reaction is carried out, the type of buffer, and
the presence of activators or inhibitors.
• Because the definition of 'international units' does not take these factors
into account, results from different laboratories, apparently expressed in
the same units, may not be directly comparable. Therefore, plasma
enzyme activities must be interpreted in relation to the reference ranges
from the issuing laboratory.
32. 2. Physiological factors affecting enzyme activities include
for example:
a. Age: Plasma AST activity is moderately higher during the
neonatal period than in adults, plasma alkaline phosphatase
activity is higher in children than in adults and peaks during
the pubertal bone growth spurt before falling to adult levels.
b. Sex: plasma γ-glutamyl transferase activity is higher in men
than-in women.
c. physiological conditions: Plasma alkaline phosphatase
activity rises during the last trimester of pregnancy because of
the presence of the placental isoenzyme: several enzymes,
such as the transaminases and creatine kinase rise moderately
in plasma during and immediately after labour or strenuous
exercise.
