tailieunhanh - PDQ BIOCHEMISTRY - PART 6

Tuy nhiên, nếu các ga tàu điện ngầm tràn ngập với những hành khách nonpaying (chất ức chế cạnh tranh), kéo dài ức chế enzyme sẽ làm theo. Nếu bạn còn nhớ tốc độ so với lô nồng độ chất nền, chúng tôi cho thấy trong Chương 3, ảnh hưởng của nồng độ cố định của chất ức ch | 172 PDQ BIOCHEMISTRY Normal Liver Fecal Urinary Stercobilinogen Urobilinogen Neonatal Jaundice Inadequate Liver Processing Increased Hemolysis Urobilinogen Decreased Hemolytic Anemia Increased Bilirubin Production Urinary Urobilinogen Increased Viral Hepatitis Damaged Hepatocytes Decreased Ductule Function Urinary Bilirubin t and Urobilinogen Decreased Bile Duct Obstruction Decreased Absent Chapter 5 Hemoglobin Porphyrias and Jaundice 173 . hemolytic anemias including sickle cell anemia caused by HbS a hemoglobinopathy hepatic infectious hepatitis liver poisoning or posthepatic blockage of the common bile duct pancreatic cancer . Table 5-4 Findings with Jaundice Caused by Different Conditions Pathology Bilirubin serum Bilirubin urine Urobilinogen urine Stercobilinogen Neonatal jaundice Indirect ị ị Hepatitis Indirect direct T ị ị Hemolytic anemia Indirect Absent T T Obstructive jaundice TDirect T Absent ị Complete blockage of bile duct . tumor . A stone may allow intermittent flow of bile giving changing levels of urinary urobilinogen and stool stercobilinogen Figure 5-25 Mechanisms involved in jaundice in a variety of conditions. Several pathologic states are presented in comparison with normal bilirubin metabolism. Neonatal jaundice arises because an immature liver cannot adequately handle bilirubin and its accelerated formation resulting from increased levels of hemolysis. There is thus an increase in serum indirect nonconjugated bilirubin and possible declines in direct bilirubin secretion and in fecal stercobilinogen and urinary urobilinogen levels compared with normal infants. In hemolytic anemia liver function is normal but there is increased metabolic traffic of bilirubin coming from premature red cell breakdown. Serum indirect bilirubin increases and with a larger secretion of direct bilirubin into the bile come elevated levels of urine urobilinogen and fecal stercobilinogen. Urinary bilirubin is absent as indirect bilirubin is not particularly water