-
Arsenic Poisoning
- aresenite most toxic form
- Acts on enzymes containing
- lipoic acid (ex: PDH, glyceraldehyde 3 phophate dehydrogenase)
- Reoxidizes the reduced
- disulfide bond --> increases its stability so pyruvate and lactate
- builds up
- Causes a decrease in E.
- production ---> acidosis
-
Thiamine Deficiency
- Deficiency in thiamine
- (vitamin B1) results in PDH complex E1 not being able to decarboxylate
- pyruvate because the enzyme will present as an apoenzyme with no thiamine
- pyrophosphate cofactor bound to it
- Mild deficiency: GI
- complaints, "pins and needles"/burning feet
- Severe deficiency: Beri-Bery
- or Wernicke-kOrsakoff Syndrome
-
-
Asia- eating polished rice
- with husk removed (source of thyiamine)
- Wet and dry type- depending
- if edema is present or not
- Nueromuscular cardiovascular
- disorders, delirium, memory loss, muscle weakining, increased venous
- return to heart, peripheral vasodilation, opthalomogplegia
- Death by high output cardiac
- failure
-
Wernicke-Korsakoff Syndrome
- Chronic alcohol abuse &
- poor nutrition
- Wernicke's encephalopathy
- (acute phase): delerium, mental derangement, ataxia, opthalmoplegia
- Korsakoff psychosis (chronic
- phase)- anterograde amnesia, distinct pattern of brain damage (focal
- adhesions) …IRREVERSIBLE
- Diagnosis- urinary thiamine
- excretion, transketolase activity in RBC, lactate/pyruvate levels
- post-oral glucose pill
- Treatment- thiamine
- injections intramuscularly (before chronic phase)
-
PDH Deficiency
- Defect of E1
- Inability to convert pyruvate
- to acetyl coA
- X linked dominant (but both M
- and F)
- Increase blood levels of:
- pyruvate, lactate, alanine, alpha keto glutarate
- Causes congenital lactic
- acidosis
- Symptoms: mental retardation,
- microcephaly, otpical atrophy, motor dysfunction, spinocerebllar ataxia
- Treatment: low car diet
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