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Flashcards in Hepatobiliary Deck (96):
1

Brown pigment stones typically arise secondary to what?

Infection of the biliary tract

2

What enzyme is typically involved in the formation of brown pigment stones?

Injured hepatocytes and bacteria release beta-glucuronidase which contributes to the hydrolysis of bilirubin glucuronides - increasing the amount of unconjugated bilirubin in bile

3

What class of HIV drugs have a side effect of hyperglycemia?

Protease inhibitors (e.g. idinavir)

4

What does gallbladder hypomotility often lead to?

Bile precipitation and the formation of biliary sludge

5

Normal blood sugar levels, severe cardiomegaly, glycogen accumulation in lysosomes, normal glycogen structure - disease and enzyme deficiency?

Type II: Pompe's disease - deficiency of lysosomal acid alpha-glucosidase

6

Muscle glycogen phosphorylase deficiency, weakness and fatigue with exercise, little or no rise in blood lactate levels after exercise, high level of glycogen in muscles - disease and enzyme deficiency?

Type V: McArdle's disease - deficiency of glycogen phosphorylase

7

Hepatomegaly, fasting hypoglycemia, lactic acidosis, hyperuricemia, hyperlipidemia, increased glycogen storage but normal structure - disease and enzyme deficiency?

Type I: von Gierke's disease - deficiency of glucose 6 phosphatase

8

How is rectal drug administration different from oral drug administration in terms of bioavailability?

Rectal drug administration partially bypasses first pass metabolism - drained by superior, middle, and inferior rectal veins. While the superior goes to the liver, middle and inferior go straight to systemic circulation.

9

High intracellular NADH in the setting of hypoglycemia is suggestive of what?

Since NADH is a carrier of energy, it suggests that a fuel other than glucose is being metabolized (e.g. alcohol)

10

What blotting technique uses a double stranded DNA probe?

Southwestern - used for proteins that bind DNA

11

What are some examples of DNA binding proteins (i.e. what you would use a southwestern blot for)?

Transcription factors (e.g. c-Jun and c-Fos), nucleases, histones

12

Toxicity of what drug is treated by donation of sulfhydryl groups?

Acetaminophen - treated with N acetylcysteine

13

How does acute hepatitis A typically present?

Fever, dark urine, malaise, nausea, vomiting, mild abdominal pain with hepatomegaly and jaundice

14

What is the function of acyl CoA dehydrogenase?

First enzyme in the series of reactions that breaks down acyl CoA to ketone bodies (beta oxidation) once it is brought into the mitochondria by the carnitine shuttle

15

Why are pregnant women at increased risk of gallstones?

Estrogen-induced cholesterol hypersecretion and progesterone-induced gallbladder hypomotility

16

Which class of viruses obtain their envelope by budding through the host cell nuclear membrane rather than the plasma membrane?

Herpesviruses

17

Why does Hepatitis D need to coinfect with Hepatitis B?

Needs viral coat (from Hepatitis B) before it can infect hepatocytes and multiply

18

Why is Hepatitis C genetically unstable?

Lacks proofreading 3' to 5' exonuclease activity

19

Acute inflammation of the gallbladder is initiated 90% of the time by?

Gallbladder outflow obstruction

20

Cardiac arrhythmia, hepatomegaly, dark skin (hyperpigmentation) - diagnosis?

Hemochromatosis

21

What are the 3 ketone bodies?

Acetone, acetoacetic acid, beta-hydroxybutyric acid

22

What causes spider angiomata?

Hyperestrinism

23

How does Hepatitis B replicate?

Double stranded DNA --> Template + RNA --> Progeny double-stranded DNA

24

What is the significance of prokaryotic 16S rRNA sequence?

Found in the 30s ribosomal subunit and contains a sequence complementary to the Shine Dalgarno sequence on mRNA - by allowing mRNA to bind to the ribosome, it initiates protein translation for prokaryotes

25

The most common form of galactosemia results from deficiency of what enzyme?

Galactose-1-phosphate uridyl transferase

26

Why is effective immunity against infection often not conferred for Hepatitis C?

Remarkable variety in the antigen structure of the envelope protein

27

What is a major gallbladder complication in the hospitalized/severely ill?

Acute acalculous cholecystitis - inflammed and enlarged gallbladder without gallstones

28

What is the most common malignant hepatic lesion?

Metastasis from another primary

29

What nutritional deficiencies do we worry about with prolonged cholestasis?

Fat soluble vitamins (A, D, E, K)

30

Why would someone with cholestasis get osteomalacia?

Vitamin D deficiency (Vitamin D is a fat soluble vitamin)

31

What does an acidophilic body signify in a hepatocyte?

Apoptosis from viral hepatitis - also called Councilman bodies and apoptotic bodies

32

What is the inheritance pattern of classic galactosemia?

Autosomal recessive

33

Presentation: 3 week old infant with persistent jaundice, dark urine, acholic stools, conjugated hyperbilirubinemia - diagnosis?

Biliary atresia

34

Neurologic symptoms with hepatic damage (elevated liver enzyme) should make you suspicious of what?

Wilson disease

35

What is one of the fastest/easiest diagnostic tools for Wilson disease?

Look for Kayser-Fleischer rings with slit lamp examination

36

What happens to BUN in liver disease?

Typically decreased because less ammonia is converted to urea

37

A moderately elevated alkaline phosphatase of unknown etiology should be followed up with by what test to check for liver disease?

Gamma-glutamyl transpeptidase - more specific for hepatocytes and biliary epithelia

38

Describe the series of reactions by which the liver is able to use the breakdown products of triglycerides.

1. Triglycerides broken down into glycerol and fatty acids (fatty acids go on to beta oxidation)
2. Glycerol goes to the liver where it is converted to glycerol 3-phosphate by glycerol kinase
3. Glycerol is converted to DHAP which can be broken down into energy (via glycolysis) or glucose (gluconeogenesis)

39

What are the 3 progressive stages of alcohol associated hepatic injury?

1. Steatosis (reversible)
2. Hepatitis (reversible)
3. Cirrhosis (irreversible)

40

What lab tests are markers of cirrhosis (i.e. irreversible liver damage)?

Prolonged PT and decreased serum albumin (indicate that liver function has been impaired; not just hepatocellular damage as is marked by AST/ALT)

41

What is the genetic abnormality in hemochromatosis?

Hemochromatosis gene HLA-H on chromosome 6 codes for a molecule that affects iron absorption from GI tract

42

Homeobox genes typically code for what?

DNA-binding transcription factors that alter the expression of genes involved in morphogenesis

43

Where are enhancers/repressors located vs. promoters?

Enhancers/repressors can be located anywhere vs. promoters which are located 25 or 70 bases upstream of the target gene

44

What step of the TCA cycle is often inhibited in alcoholics? Why?

Alpha-ketoglutarate to succinyl coA because the enzyme alpha-ketoglutarate dehydrogenase requires thiamine as a cofactor (and alcoholics are often thiamine deficient)

45

What is the point of adding primaquine to a malaria treatment regimen?

Prevent disease relapse - primaquine kills the intrahepatic merozoites of vivax and ovale which chloroquine does not cover

46

Liver biopsy shows hepatic fibrosis without fat accumulation. Also shows accumulation of small chain dextrin-like material within the cytosol of the hepatocytes - what enzyme is deficient?

Debranching enzyme deficiency (Cori disease) - glycogen can't be broken down so patients present with hypoglycemia, hypertriglyceridemia, ketoacidosis, hepatomegaly

47

Describe what happens in zero order kinetics.

Constant amount of drug is metabolized per unit time, independent of concentration

48

Intense liver damage following a seemingly successful surgery should make you suspicious of?

Fulminant hepatitis from drug reaction to inhaled anesthetic (e.g. halothane)

49

What would you expect to see on lab tests for a fulminant hepatitis from a drug reaction to anesthetics?

Elevated aminotransferase levels, prolonged PT time, eosinophilia

50

What should be you be suspicious of in a patient with progressive exertional dyspnea and elevated liver enzymes?

Alpha1 anti-trypsin deficiency

51

What causes the pulmonary symptoms in alpha1 anti-trypsin deficiency?

Interalveolar septa destruction

52

G to T mutation in p53 from eating moldy grains?

Aflatoxin causing liver cancer

53

What is the tumor marker for hepatocellular carcinoma?

AFP

54

What does anicteric mean?

No jaundice

55

What is the most common benign liver tumor?

Cavernous hemangioma

56

Liver histology showing cavernous blood-filled vascular spaces lined by a single epithelial layer - diagnosis?

Cavernous hemangioma

57

What is lipoic acid a cofactor for?

Pyruvate dehydrogenase, alpha ketoglutarate dehydrogenase, branched-chain ketoacid dehydrogenase

58

What does a deficiency in pyruvate dehydrogenase lead to?

Lactic acidosis

59

What does a deficiency in branched chain ketoacid dehydrogenase lead to?

Maple syrup urine disease

60

Which hepatitis virus has a high mortality rate in infected pregnant women?

Hepatitis E

61

What type of virus is hepatitis E?

Unenveloped, single stranded RNA

62

What kind of imaging test can be used to confirm diagnosis of acute calculous cholecystitis?

Failed gallbladder visualization on radionuclide biliary scan

63

Histology: hepatocytes filled with fine cytoplasmic protein granules - diagnosis?

Hepatitis B - hepatocellular cytoplasm is filled with spheres and tubules of HBsAg and take on a finely granular, eosinophilic appearance commonly described as "ground glass"

64

Isoniazid can directly damage which organ?

Liver

65

Where is transketolase located?

Cytoplasm

66

Where is pyruvate carboxylase located?

Mitochondria

67

Where is ornithine transcarbamoylase located?

Mitochondria

68

Where is succinate dehydrogenase located?

Mitochondria

69

Describe the first step of gluconeogenesis.

Since pyruvate cannot be directly converted back to phosphoenolpyruvate, it must first undergo biotin dependent carboxylation to oxaloacetate in the mitochondria (which will then become malate, shuttle out and be converted back to oxaloacetate which can become phosphoenolpyruvate)

70

What is the role of acetyl CoA in gluconeogenesis?

Important allosteric activator of gluconeogenesis that acts by increasing the activity of pyruvate carboxylase

71

Why is there a bimodal distribution for the speed of isoniazid metabolism?

Metabolized by acetylation - there are genetically fast and genetically slow acetylators in the population

72

What is the significance of a porcelain (calcified) gallbladder on imaging?

Increased risk of gallbladder carcinoma

73

What triggers neoplastic changes with HBV infection?

Viral integration into the host DNA

74

What metabolic enzyme deficiency is associated with the formation of cataracts?

Galactokinase because you get a build up of galactose which is converted to galactitol which can accumulate in the lens of the eye

75

How would you microscopically characterize a cirrhotic liver?

Diffuse hepatic fibrosis with replacement of the normal lobular architecture by fibrous-lined parenchymal nodules

76

What is the most likely outcome for someone infected with Hepatitis C?

Stable chronic hepatitis

77

What is affected in Wilson's disease aside from the liver?

Cornea and basal ganglia

78

Patients with hemochromatosis are at increased risk of developing what?

Liver cirrhosis and hepatocellular carcinoma

79

Which Hepatitis B antigen is a non-infective glycoprotein that forms spheres and tubules?

HbSag - The surface antigen is actually part of the envelope.

80

The oxidative reactions of the HMP shunt are required for what?

Anabolic reactions that require NADPH as an electron donor (e.g. cholesterol and fatty acid synthesis)

81

question 8

come back to this

82

What portions of mRNA are not transcribed from a DNA template?

Post-transcriptional modifications:
1. 5' cap
2. Poly A tail

83

Which hepatitis virus integrates itself into the host genome?

Hep B

84

What are the ways in which Hepatitis A can be inactivated?

Water chlorination, bleach, formalin, ultraviolet irradiation, boiling for 1 minute

85

What is pantothenic acid?

Coenzyme A

86

Decreased ceruloplasmin is associated with what disease?

Wilson's

87

What is the best treatment for Wilson's disease?

Penicillamine chelation - removes excess copper in tissues

88

Liver biopsy showing extensive lymphocyte infiltration and granulomatous destruction of interlobular bile ducts should make you suspicious of?

Primary biliary cirrhosis

89

45 year old obese female with fever and prolonged episode of severe right upper abdominal pain after fatty meal ingestion?

Acute cholecystitis

90

38 year old male with long history of ulcerative colitis who presents with fatigue and elevated alkaline phosphatase?

Primary sclerosing cholangitis

91

65 year old Caucasian female with weight loss, abdominal discomfort, jaundice, epigastric mass?

Pancreatic cancer

92

35 year old homeless male with fever, abdominal pain, and jaundice?

Acute cholangitis

93

What does liver biopsy show in children with Reye syndrome?

Microvesicular steatosis

94

Describe the mechanism of liver injury with Hepatitis B.

Presence of viral HBsAg and HBcAg on infected hepatocyte surface stimulate the host's cytotoxic CD8+ T lymphocyte to destroy the infected cells

95

45 year old Caucasian female with long history of pruritus and fatigue who developed pale stool and xanthelasma?

Primary biliary cirrhosis

96

When do we convert glucose to ribulose-5-p?

HMP shunt