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Clinical Biochemists play a role in producing and interpreting results of biochemical analyses performed on blood and other body fluids to help in the diagnosis and management of disease.
Creatine kinase is an enzyme that is present in the heart, brain, and skeletal muscle. It is also known as phosphocreatine kinase a type of protein called an enzyme. Enzymes are proteins that assist in cells performing their normal functions.(4) In muscle, for example, CK helps cells make the energy needed to move. CK occurs in three major forms, called isoenzymes:
CK-MB (found in the heart muscle),
CK-BB (found in the brain), and
CK-MM (found in the heart and other muscles).
These isoenzymes are determined by the differences in gene, amino acid sequence, and tissue localization. CK-MM and CK-BB are both forms of cytosolic and exist as dimers. Under some conditions cytosolic CK can exist as the MB heterodimers. Creatine kinase is consisted of two dissociable subunits with no disulphide bonds. The normal function of CK in cells is to add a phosphate group to creatine and to form phosphocreatine.(1)(2)
Lactate dehydrogenase is an enzyme found in almost all body tissues and only a small amount of it is usually detectable in the blood. It is involved with glucose metabolism. It is a tetramer of four subunits and can exist in five different forms called isozymes. Within the tissue cells LDH is released into the bloodstream when cells are damaged or destroyed. Damage to any of these tissues will cause a release of the LDH enzyme. Lactate dehydrogenase has two different subunits one primarily found in the heart muscle and the other in skeletal muscle. (3)
Table1: Table showing absorbance readings of each of the patients with Creatine Kinase total at 1min intervals
This table is showing the absorbance readings that were determined by the 3 patients. These results will be used to calculate the absorbance change per min.
Figure2. Graph to show the absorbance reading of each of the patients against time.
This graph will be used to determine the change in absorbance(gradients).
Calculations to determine the change in absorbance per min for each of the patients
(0.465-0.360)=0.105 the change of absorbance value calculated can now be used in the equation: Units l-1 = ΔAbs min-1 x 1000
The extinction coefficient for NADPH is 6.22.103 M-1. cm-1 at 340 nm.
1 μmol NADPH in 1 ml in a 1cm cuvette has an absorbance of 6.22
Enzyme units in 0.04 ml are given by ΔAbsorbance min-1 divided by 6.22.
Units l-1 = 0.105 x 1000
6.22 0.04 = 422.06l-1
(0.360-0.256)=0.104=change in absorbance
Units l-1 = 0.104 x 1000
6.22 0.04 =418.006l-1
(0.256-0.146)=0.104=change in absorbance
Units l-1 = 0.104 x 1000
6.22 0.04 =412.122
The average change in absorbance of F patient is 0.104 and the unitsl-1 is 417.43
(0.051-0.042)=0.009=change in absorbance per min
Units l-1 = 0.009 x 1000
6.22 0.04 =60.30
Units l-1 = 0.012 x 1000
6.22 0.04 =48.23
Units l-1 = 0.016 x 1000
6.22 0.04 =64.31
The average change in absorbance of W patient is0.012 and the unitsl-1 is 57.61
Units l-1 = 0.181 x 1000
6.22 0.04 =727.49
Units l-1 = 0.363 x 1000
6.22 0.04 =735.53
Units l-1 = 0.18x 1000
6.22 0.04 =723.47
The average change in absorbance of H patient is 0.241 and the unitsl-1 is 728.83
Creatine kinase MB
Figure 3. Showing the readings of Creatine MB
(0.086-0.067)=0.019 change in absorbance value
Units l-1 = 0.0038x 1000
6.22 0.04 =15.27
For CK-MB, the true value is 2x the value= 15.27-2=30.55
Units l-1 = 0.0004x 1000
6.22 0.04 =1.61
Units l-1 = -0.0002x 1000
6.22 0.04 =-0.80
Willis- 1.61/57.61-100= 2.79%
Results from lactase dehydrogenase
Table2: Table showing the absorbance reading of the serum samples with time
This table shows absorbance reading of serum samples taken from blood from a patient at 24 hour intervals for 3 days. This data will be used to plot a graph to find out the change in absorbance per min(gradient).
Figure4. Graph showing the absorbance against time
This graph is showing a line of best fit through each of the serums. A line of best fit has been drawn through each line to find out the change in absorbance. From determining the change in absorbance we then use it in the following equation to calculate the units of lactase dehydrogenase per ml of serum in each sample.
A = E.c.l or c = A/E.l
Where: c = ïmol ml-1
A = ï„ A340 min-1
E = 3.11
Absorbance change per min=0.046 of Day0
Absorbance change per min=0.232 of Day1
Absorbance change per min=0.667 of Day2
Absorbance change per min=0.241of Day3
Using the equation c=A/E.l
Day 0 0.046/3.11=0.015/0.05=0.30ml-1
Day 1 0.232/3.11=2.109/0.05=1.49ml-1
Table3: Table showing the concentration of lactate dehydrogenase in blood
Results from the Creatine kinase activities in serum show Freeman is the patient likely to have a heart attack. This is because he has a CK-total of 417.23l-1 and CK-MB of 30.55 which indicate the results are very high and has the likelihood of heart attack. The reference ranges for Creatine kinase show males<200 iu/l and females<130 iu/l (5) which indicate the patient freeman has a higher indication of a heart attack according to the reference ranges. Figure 2 shows that an increase in time increases the absorbance readings of Creatine total. An increase in Creatine kinase indicates elevated levels of CK resulting in an acute myocardial infarction. An increase in CK indicates damage has been made to the heart or other muscles. This can indicate the patients muscles have been used heavily. References show Creatine MB levels rises due to heart attacks. It rises within 6 hours and reaches peak level around 18 hours and returns to normal with 2-3 days.
Normal LDH levels vary with age, being higher in childhood due to bone growth. Normal ranges of LDH vary between laboratories. The normal range for adults is in the range of 200 units/litre. Results show the concentration of lactate dehydrogenase in blood is very high compared to the normal range. Results also show LDH levels peaked at day 2 this is an indication that patient has had a heart attack. The LDH level rises within 24 - 72 hours after a heart attack, peaks in 3 - 4 days, and returns to normal in about 14 days. Results show this. The reference ranges of lactate dehydrogenase show the serum levels raises within 24 hours after the infraction and then reaches peak level around 2-3 days and then returns to normal within a week. Results from the experiment show this happens. (6) Results for Hardy and wallis are hard to identify what the patients diagnosis is and is difficult to say what dignosis the patient has as theres not much information on the the patients race and age.