vitamin deficiencies

Question 1

copper defficiency results in ______ because copper is a co-factor in what reaction?

Answer 1

impaired wound healing (primary and secondary intention) due to impaired collagen production

copper is a cofactor for lysl oxidase which facilitates crosslinking of lysine and hydroxilated lyseine residues between collagen fibrils

primary intention occurs when wound edges are brought together (e.g. via suturing) and does not involve much scar formation

secondary intention occurs when wound edges are not approximated and granulation tissue fills the defect. fibroblasts lay down type III collagen then collagenase removes type III and replaces it with type I during scar formation.

Question 2

zink deficiency results in ______ because copper is a co-factor in what reaction?

Answer 2

impaired wound healing due to impaired scar formation

zink is a cofactor for collagenase which mediates conversion of type III collagen (in granulation tissue) to type I collagen (primarily in secondary intention)

Question 3

cheilitis (cracked agles of hte mouth)
glossitis with a magenta colored tongue and
corneal cascularizaation

are signs of what deficiency?

Answer 3

riboflavin

Question 4

what enzymes use riboflavin as cofators?

Answer 4

key componant of FAD succinate dehydrogenase of TCA cycle (aka complex 2 of electron transport chain)

also key comonent of FMN - used by complex I of the electron transport chain (NADH dehydrogenase)

Question 5

what does mild niacin deficiency lead to? Severe?

Answer 5

glossitis

pallegra
dermatitis (usually around necklace + sun exposed areas)
diarrhea
dementia

Question 6

what condition is associated with niacin deficiency?

Answer 6

carcinoid syndome due to excessive serotonin from a carcinoid tumor usually of the small bowel

Question 7

what amino acid can be used endogenously to synthesize niacin?

Answer 7

tryiptophan

with carcinoid tumor tryptophan is shunted to make serotonin causing a secondary niacin deficiency

Question 8

deficiency in what co-factor can lead to niacin deficiency?

Answer 8

B6

required for endogenous conversion of triptophan to niacin

Question 9

pt has diarrhea, memory impairment and an erythematous rash. Triptophan is found in the urine. What was the underlying cause of these symptoms?

Answer 9

niacin deficiency secondary to Hartsnup disease

autosomal recessive defect in intestinal and renal transporters for neutral amino acids - causes tryptophan excretion in the urine

triptophan is necessary for endogenous synthesis of niacin.

niacin deficiency leads to pallegra.

Question 10

what vitamin deficiency causes:
dermatitis
enteritis
alopecia
adrenal insuficiency

Answer 10

B5 (pantothenic acid) - needed for CoA

Question 11

what does vitamin B6 deficiency cause?

Answer 11

peripheral neuropathy and convulstions due to deffective neurotransitters synthesis

sideroblastic anemia due to defective heme sysnthesis

Question 12

what drug should B6 not be taken with?

Answer 12

L-DOPA

B6 catylizes peripheral conversion to dopamine so parkinsons patient will have less get to brain

Question 13

what vitamin deficiency causes:
dermatitis
alopecia
enteritis

Answer 13

biotin (B7) deficiency

Question 14

what enzymes is biotin a co-factor for?

Answer 14

acytl-CoA carboxylase - converts actylCoA to malonylCoA in fatty acid synthesis

pyruvate carboxylase - converts pyruvate to oxaloacitate enzyme catylist is Acetyl Co-A

propionylCoA carboxylase - converts prioionyl CoA to methylmalonylCoA in metabolism of odd chain fatty acids. Methylmalonyl coA is then converted to succinyl Co A for TCA - requries B12 co-factor