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Zone I = periportal zone
- affected FIRST by viral hepatitis
- ingested toxins (ie: cocaine)
Zone II = intermediate zone
- yellow fever!
Zone III = pericentral vein (centrilobualr zone)
- affected 1st by ischemia
- contains the cytochrome P450 system
- most sensitive to metabolic toxins
- site of alcoholic hepatitis
What are the causes of chronic gastritis?
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What are the causes of chronic gastritis?
- caused by continuous inflammation of the gastric mucosa leading to
atrophy (hypochlorhydria --> hyperstrinemia) and intestinal metaplasia
(increased risk of gastric cancers)
Type A = autoimmune-->body/fundus
autoantibodies against parietal cells and IF
- increased risk of pernicious anemia and gastric adenoCA
Type B = H. pylori-->antrum
- most common
- H. pylori infection
- increased risk of PUD and MALT lymphoma
Base Excision Repair
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Note:
- endonuclease cleaves the 5' end
- lyase cleaves the 3' sugar end
- both will before the incorrect/damaged nucleotide
So the order of enzymatic actions:
glycosylase --> endonuclease --> lyase --> DNA
polymerase --> ligase
What is Zollinger-Ellison syndrome?
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, What is Zollinger-Ellison syndrome?
- caused by gastrin secreting neuroendocrine tumors
(gastrinomas) that are most commonly located in the small
intestine or pancreas
- gastrin produced by these tumors often leads to excess
gastric acid production resulting in multiple peptic ulcers
that can be located beyond the duodenal bulb (closest
part to stomach)
Can also have:
- abdominal pain
- reflux
- diarrhea (due to inactivation of pancreatic/intestinal
exnymes by gastric acid)
Diagnosis:
- secretin stimulation test: basal and stimulated gastrin
levels
- also should undergo testing to exclude MEN 1
Peutz-Jeghers Syndrome
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Autosomal Dominant
- numerous hamartomas throughout GI tract
-hyperpigmented mouth, lips, hands, genitalia
- increased risk of breast and GI cancers (colorectal, stomach, small bowel,
pancreatic)
Intussusception
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, - telescoping of proximal bowel segment into distal
segment--> ileocecal junction
Sx:
- intermittent abdominal pain with "currant jelly" stools
- bulls eye appearance on ultrasound
- UNUSUAL in adults (associated with intraluminal mass or
tumor)
- majority of cases are in children (associated with recent
viral infection like adenovirus --> Peyer patch hypertrophy -
-> creating a lead point)
Abdominal emergency
For a cavernous hemangioma of the liver:
- benign or malignant?
- age of onset?
- what is it?
- is biopsy indicated for diagnosis?
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For a cavernous hemangioma of the liver:
- benign or malignant: BENIGN, most common benign
tumor of the liver
- age of onset: onset 30-50 years old
- what is it: thought to be congenital malformations that
enlarge by ectasia. microscopically, they consist of
cavernous, blood-filled vascular spaces of variable size
lined by a single epithelial layer. collagenous sacrs or
fibrous nodules may be seen in association with thrombosis.
- is biopsy indicated for diagnosis: NO biopsy is actually
contraindicated because of the concern for hemorrhage