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Chinese Medical Information Portal Website (Taiwan Medical Network-TMN) - OldDoc Wu's Series
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(Established in March 1996)
liver-diseases
Protein metabolism
Dr. Wu's Liver diseases
for professionals (medical students and residents) and consumers

by Jau-Shin WU, M.D., Ph.D.

(Posted Sep. 16, 1996; Updated May 14, 2009)

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Protein metabolism

(Key words: protein, albumin, serum protein electrophoresis, coagulation factor, rapid turnover protein, PIVKA, APTT, PT, DIC, Vitamin K dependent factor)

1) Albumin

  1. Hepatocyte: the only site of albumin synthesis
  2. Post and Patek (1942) relation of serum albumin to prognosis of cirrhosis
  3. Salting-out method:include globulins
  4. Degradation
  5. Distribution---cirrhotic patient: plasma volume increase by 25%, the actual amount of albumin not as little as measured
  6. Loss---A/G ratio: not suitable expression ---renal disease, protein loosing gastro-enteropathy
  7. Half life: 19 ~ 21 days
2) Serum protein electrophoresis (R-E system--gamma-globulin)

  1. Five fractions--A, alpha-1-globulin, alpha-2-globulin, beta--globulin, gamma-globulin
  2. Total protein amount
  3. Except for gamma-globulin, other four proteins are only synthexsized by liver cells
  4. gamma-globulin: synthesized by B-lynphocyte
  5. Every protein is simple protein: less sensitive
  6. alpha-1-G is more sensitive than alpha-2-G and beta-G in reflection of liver cell damage
  7. alpha-1-AT(antitrypsin): positive acute reactanct protein
                    acute hepatitis:  ¡ô
    		massive hepatic necrosis:  ¡õ		
    
3) Rapid turnover protein

  1. Albumin half life ------ 19 ~ 21 days
  2. Do not reflect defect of capacity of protein synthesis in early stage liver cell damage
  3. Some globulins -----half life of several hours to days
    • -- Prealbumin, alpha-1-acid glycoprotein, hemopexin, transferin
    • -- Positive acute phase reactant protein---- £\1-antitryposin, alpha-2-HS-glycoprotein, ceruloplasmin
  4. Most of alpha-1-glycoprotein: alpha-1-AT
  5. Polyacrylamide gradient gel electrophoresis, Single Radial Immuno Difusion
  6. pre-A, alpha-1-AG and alpha-1-AT, Ceruloplasmin
4) Coagulation factors

  1. I, II, III, IV, VII, IX, X, XII, XIII
  2. Except for VIII, liver is the only site for synthesis
  3. Reflect the damage of liver cell
  4. PT (Prothrombin Time):---I, II, V, VII, X (Extrincic pathway)
  5. APTT (Activated Partial Throboplastin Time): --- I, II, V, IX, XI, XII (intrincic pathway)
  6. Normotest (Owren): --- II, X, VII
  7. Fibrinogen
  8. Factor V
  9. Factor VII
Coagulation system

Extrincic pathway: Tissue factor ---¡÷VII
Intricic pathway: XII ¡÷XI¡÷IX¡÷VIII
		VII  +  VIII   ¡÷    X   ¡÷   Xa
		Xa   +  V    ¡÷    II   ¡÷    Thrombin
			Thrombin    ¡÷   I   ¡÷  Fibrin
			Thrombin    ¡÷   XIII   ¡÷  prevent fibrinolysis
PT (Prothrombin Time)

  • If APTT is normal --- VII deficiency
  • Factor VII --- shortest half life (6 hours)
APTT (Activated Partial Thromboplastin Time)

If PT is normal --- IX, XI, XII deficiency Normotest (Owren's, Hepatoplastin test)

  • Not influenced by PIVKA (prtein induced by vitamin K absence)
  • Thrombotest: influenced by PIVKA, test for vitamin K deficiency
Vitamin K-dependent factors

  • II, VII, IX, X
  • influence both PT and APTT
DIC (Disseminated Intravascular Coagulation)

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(By Jau-Shin Wu, M.D.; Posted Sep. 16, 1996; Revised May 12, 2009)

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