Lab 10- Liver 2 Flashcards
What can impaired protein synthesis cause?
decreased colloid osmotic (oncotic) pressure of the blood, quicker ESR (erythrocyte sedimentation rate) (hypoalbiminaemia), and longer PI (prothrombin time)
Why does the blood pressure decrease with impaired protein synthesis
(due to hypoalbuminaemia),
Why does the PI time increase with impaired protein synthesis
lower fibrinogen level
What can impaired liver function lead to?
hormonal imbalances
lysomal enzymes with severe liver necrosis
catepsin-D, carboxypeptidase) can be elevated in the blood
Parameters to be measured:
TP, albumin, and fibrinogen concentration by spectrophotometric, refractometric methods and fibrinogen by the thrombin time.
When can edema be expected?
if albumin concentration is < 20 g/l, and there is edema formation if albumin concentration is < 11 g/l
how do we measure alpha and beta globulins
electrophoresis
how are coagulation factors measured?
APTT and PR
Why do we need to measure ammonia conc?
1) in carnivores to diagnose severe decrease of liver function (i.e. cirrhosis), portosystemic shunt
2) in ruminants as a consequence of ruminal alkalosis, or decomposition of ruminal fluid severe systemic alkalosis can be developed due to hyperammoniaemia,
3) in case of horse, rabbit pathologic breakdown of ingest in the colon or caecum or in case of liver failure .
Where is ammonia produced and absorbed
produced in the intestines by the bacteria, it is absorbed to the portal vein
How is ammonia detoxified
in the liver
- ornithine cycle
- GLDH untilised alpha keto glutaric acid
After what time period can we take ammonia measurements?
How should we take samples.
animals should starve for 24 hours.
We take blood samples to tubes that contain EDTA or citrate as an anticoagulant.
Samples should be taken by avoiding air - contamination of them
Normal value for ammonia conc
<120 μmol/l in dogs
<175 μmol/l in cats.
Basis of ammonia measurement (standard) method
ammonia with alpha-ketoglutaric acid and NADH+ H+ and GLDH enzyme produces glutamic acid and NAD+
What type of sample do we need for ammonia conc measurement?
plasma sample for standard method
Whole blood sample for portable ammonia checker
Ammonia tolerance test:
- when do we perform this?
when basal NH3-concentration values do not show alteration and the suspect of portosystemic shunt is strong
Ammonia tolerance test:
pretreatment
with neomycin
Causes of increased NH3.concentration in the blood
Impaired liver function - decreased urea prod
Ruminal alkalosis or ammonia toxicosis
Intestinal overgrowth of ammonia producing bacteria
Congenital enzymopathies
mild vs severe liver damage effect on cytoplasmic and mitochondrial enzymes
mild - cytoplasmic increase
severe - mitochondrial ones increase
AST (Aspartate-aminotransferase)
- location
mitochondria
muscles
RBC
AST (Aspartate-aminotransferase)
- function
converts alpha-keto-glutaric acid to L-glutamic acid, and L-aspartate to oxalic acetic acid.
AST (Aspartate-aminotransferase)
- Basis of measurement method
Oxalic-acetate with NADH+H+ and malate-dehidrogenase (this is in the reagent) produces malate and NAD+ .
This NADH+H+ →NAD+ change cause absorbancy reduction. The speed of it is in correlation with AST activity.
AST (Aspartate-aminotransferase)
- cause of increased activity
muscle cells
- exercise, muscle necrosis, inflamation, injury, myocarditis
- Generally LDH and CK enzymes elevated too
Liver cells
- ethonal consumption, hepatopathy,
RBC
- haemolysis
AST (Aspartate-aminotransferase)
- Decreased activity
metronidasol (an antimicrobial drug, which can cause liver function problems), vitamin B6 deficiency,
