Plasma Proteins & Enzymes Flashcards
What is an indicator of Amylase & Lipase ?
- cell damage in pancreatitis
What is Creatine Kinase an indicator of?
- muscle damage
What is Alkaline Phosphatase an indicator of ?
- increases in Cholestatic liver disease
- also a marker of osteoblast activity in bone disease
What is Gamma-Glutamyl transpeptidase an indicator of?
- a sensitive but non-specific marker of liver disease
What is Aspartate Aminotransferase an indictor of?
- hepatocellular damage
- muscle damage
- red cell lysis
Where is Alkaline Phosphatase present in the body ?
- Bone, intestine & other tissues
Where is Acid Phosphatase present in the body?
- Prostate
Where is y glutamyl transferase measured in the body?
- Liver
Where is Creatine Kinase present in the body?
- Muscle - including cardiac muscle
Where is Lactate Dehydrogenase present in the body?
- Heart, liver, muscle, RBC
Where is alpha amylase present in the body?
- Pancreas
What can an increase in serum activity indicate ?
- gives an approximation to the extent of cellular damage
What are the main Blood proteins ?
- Albumins = 55%
- Globulins = 38%
- Fibrinogen = 7%
- Regulatory Proteins = <1%
- Clotting Factors = <1%
What is the normal range for albumins ?
34 - 54 g/L
What is the normal range for Globulins ?
20 -35 g/L
What is the normal range for Fibrinogen?
2-4 g/L
What is the function of Albumins ?
- to create & maintain osmotic pressure
- transport insoluble molecules
What is the function of Globulins ?
- participates in the immune system
What is the function of fibrinogen ?
- blood coagulation
What is the function of regulatory proteins ?
regulation of gene expression
What is the function of clotting factors ?
converts fibrinogen to fibrin
What is the molecular weight of Albumin ?
66.5 kDa
Where is albumin synthesised ?
in the liver
What is Albumin a part of ?
- Extravascular fluid
- CSF
- Urine
- Amniotic fluid
- Interstitial fluid
What are some properties of Albumin ?
- highly soluble in water
- half-life is 15-19 days
- maintain colloidal osmotic pressure
- can bind & transport a range of molecules
What are some examples of molecules albumin can bind to and transport ?
- free fatty acids
- amino acids
- metallic ions
- drugs
- hormones
- bilirubin
Describe Oncotic pressure
- exerted by plasma proteins like albumins
- helps push fluid into the blood capillaries & prevent fluid loss
- mostly occurs at the venular end
Describe Hydrostatic Pressure
- force exerted by fluid present within capillaries against capillary walls
- helps push fluid out of the capillaries
- helps increases filtration
- mostly occurs at the arterial end
Define Hypoalbuminaemia
low albumin concentration
- may results in oedema
What can cause oedema ?
- abnormal distribution
- decreased synthesis
- dilution due to over hydration
- abnormal excretion/degradation
Define Abnormal Distribution
- albumin moves into the interstitial space due to increase permeability of the capillary in the acute phase response
Why does decreased synthesis of albumin occur ?
- due to advanced liver disease, or malnutrition
Why might abnormal excretion/degradation occur?
- burns
- haemorrhage
- catabolic states
- nephrotic syndrome
What are Acute Phase Proteins ?
- in times of trauma, stress, tumour growth or inflammatory states the liver increases the synthesis of some proteins
- Factor VIII , Ferritin, C-reactive protein –> these are acute phase proteins
Define b2-microglobulin
- subunit of human leucocyte antigen on all cell membranes
- raised in renal tubular dysfunction
Define Caeruloplasmin
- copper transport
- reduces in Wilson’s disease
Define Ferritin
- storage of iron
- indication of body iron stores
Describe C-reactive protein
- involved in the immune response
- increased in acute illness, especially infection
Describe Haptoglobin
- binds free haemoglobin
- reduced in intravascular haemolysis
What are Isoenzymes?
- some enzymes exist in the plasma as 2 different forms
- they have different structures but perform the same function
- example = Lactate Dehydrogenase
Describe Erythrocyte Sedimentation Rate testing
- ESR = mm of plasma separated per hour
- clinically used as non-specific screening test
- not diagnostic of any particular disease but rather an indication that the disease process is ongoing
What is the function of ESR?
- detect presence of infection generally in the body
- monitor the status of chronic inflammatory disease such as Rheumatoid Arthritis
What is the normal range for Total Protein?
60-80 g/L
What can an increase/decrease in plasma protein indicate ?
- increase may mean the presence of a paraprotein (myeloma)
- decrease is often associated with a decrease in albumin
What is the Albumin Determination Principle?
- Albumin at pH 4.2 is sufficiently cationic to bind anionic dye bromocresol green
- this forms a blue-green complex
- intensity of colour is directly proportional to albumin conc. in specimen
Define Myeloma
Malignant proliferation of plasma cell
- they produce & secretes antibodies into the plasma
Describe the Biuret Test for Proteins
- 2cm^2 of sample to be tested
- 1cm ^3 of NaOH added
- mixture shook thoroughly
- 1% CuSO4 added drop by drop
- shaken after each drop
- allow mixture to stand for 5m
- violet colour = positive result
