Jaundices – species, reasons, mechanism, laboratory appearances

The quantity of total bilirubin is increased in some diseases (hyperbilirubinemia). If the level of bilirubin is more than 30mcM/L jaundice of skin and mucosa is appearenced.

There are following species of jaundice:

hemolytic one

mechanical, or obturatory one

hepatic one

Hemolytic jaundice

Causes: 1) paludal fever; 2) blood transfusion; 3) rhesus-conflict etc

Mechanism: increased hemolysis.

Laboratory appearences: The total level of bilirubin is increased due to undirect bilirubin. Color of urine isn’t changed because this kind of bilirubin doesn’t pass through kidneys. The color of feces isn’t changed too or becomes darker due to formation of a big quantity of pigments of feces.

Obturatory jaundice (mechanical one, or choolestasis)

Causes: 1) tumor of head of pancreas; 2) cholecistitis; 3) bile stone disease

Mechanism: cholestasis (obstruction of biliary tract affects efflux of bile)

Laboratory appearances: the total level of bilirubin is increased due to direct bilirubin. Urine is getting dark due to direct bilirubin (beer color). It is due to the direct bilirubin which passes through kidneys. Feces is decolorized because pigments of feces aren’t formed.

Hepatic jaundice:

Causes: 1) hepatitis; 2) cirrhosis

Mechanism: lesion of cells of liver

Laboratory appearences: The total level of bilirubin is increased due to undirect and direct bilirubin. Some hepatic enzymes are determined in blood (AlAt, AsAt etc). Urine is getting dark due to direct bilirubin (beer color). It is due to the direct bilirubin which passes through kidneys. Feces is decolorized because pigments of feces aren’t formed.

The digestion of nucleoproteins and formation of uric acid

The scheme of digestion of nucleoproteins

NPàProteins+nucleic acids

Nucleic acidsànucleotides (under action of DNA-se or RNA-se)

Nucleotidesànucleosides (under action of nucleotidases)

Nucleosidesàphosphates + nitrogenous bases (under action of nucleosidases)

Purines and pyrimidines are used on biosynthesis of nucleic acids and undergo the deamination. Deamination of them results in formation of ammonia, uric acid (purines catabolism) and beta-alanine, CO2 (pyrimidine catabolism)

The formation of uric acid:

Adenine+H2Oàhypoxanthine+NH3

Guanine+H2Oàxanthine+NH3

Hypoxanthine+[O]à xanthine

Xanthine+[O]àuric acid

<== попередня сторінка	\|	наступна сторінка ==>
The cleavage of Hemoglobin and formation of pigments of bile, urine and feces	\|	Clinical correlation of Purine’s metabolism

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