Flashcards in B vitamins Deck (34):
What is vitamin B1? What is the main molecule where vitamin B1 is found?
What is vitamin B2? What are the main two molecules that vitamin B2 is found?
FAD and FMN
What rare inherited defect in amino acid transport can cause a niacin deficiency?
Hartnup disease is an autosomal recessive defect in intestinal and renal transporters for neutral amino acids. This causes tryptophan excretion in urine and leads to pellagra
Dermatitis (classically in a "necklace" distribution around the neck)
What 2 vitamins help synthesize Niacin?
Tryptophan + B2 and B6
Pt is suspected of having thiamine deficiency. How can you confirm the Dx?
RBC transketolase activity will increase after the administration of thiamine
Confusion, ophthalmoplegia, ataxia (classic triad) +confabulation, personality change, memory loss (permanent). What nucleus is damaged?
Damage to medial dorsal nucleus of thalamus, mammillary bodies
Pt. suspected of having hypoglycemia. Treatment
give thiamine before dextrose to risk of precipitating Wernicke encephalopathy.
polyneuropathy, symmetrical muscle wasting.
Enzymes that require thymine (ATP)
α-ketoglutarate dehydrogenase (TCA cycle)
Transketolase (HMP shunt)
Pyruvate dehydrogenase (links glycolysis to TCA cycle)
Branched-chain ketoacid dehydrogenase
High-output cardiac failure (dilated cardiomyopathy)
Wet Beri Beri
What type of cells are at risk of damage with B1 deficiency?
Highly aerobic cells are damaged first because they cannot generate ATP w/o thiamine
Dermatomes affected in B3 difficiency
The 2 C’sof B2 difficiencey
FAD and FMN (she has vitamin B2 deficiency manifesting as cheilosis and corneal vascularization)
A 42 yo presents w/photophobia, inflamed lips, and fissures at the sides of her mouth. Which TCA cycle cofactors are deficient?
cheilosis and corneal vascularization
Biotin: needed for carboxylation reactions
What is Niacin used to treat? side effects?
Hyperuricemia and hyperglycemia
How can carcinoid syndrom cause pelegra?
Carcinoid syndrome is a complication of carcinoid tumors (most commonly of the small bowel) in which serotonin is systemically elaborated in great excess. Tryptophan is compensatorily shunted to make serotonin, decreasing conversion to niacin. Therefore, niacin deficiency is a potential complication of carcinoid syndrome.
Gaba, Histamine and porphyrin/heme require what vitamin
Creatine, Urea, and Nitric oxide require which a.a.
only non water soluble B vitamin
B12 cobalomin in liver
Which vitamin is needed for decarboxylation reactions and is also a cofactor for glycogen phosphorylase?
What parkinson drug therapy is decreased by vit b6 therapy
vitamin B6 can convert L-DOPA to dopamine peripherally (as opposed to in the CNS), rendering treatment less efficacious.
What complex of the electron transport chain is FMN and FAD part of.
Component of NADH dehydrogenase, aka complex I of the electron transport chain
component of succinate dehydrogenase of the TCA cycle, aka complex II of the electron transport chain
What vitamin is prevented from being absorbed by a certain protein in eggs?
Avidin... binds biotin
Two etiologies that cause a vitamin deficiency and results in the following :
antibiotic use or excessive consumption of raw egg whites
Two etiologies that cause a vitamin diffieciecy and results in the following?
what 4 neurotransmitter synthesis reactions require B6
Glutamate → GABA
Tryptophan → Serotonin
DOPA → Dopamine (dopamine can then go on to form norepinephrine and epinephrine)
Histidine → Histamine
Vitamin needed for Co-enzyme A
Medications that can induce Vitamin B6 deficiency
include oral contraceptives and isoniazid.
B6 is a precursor for what cofactor
A 32 yo woman begins taking isoniazid after a TB Dx. Later, she develops numbness and tingling in her extremities. Dx?
A man w/vitamin deficiency complains of fatigue, convulsions, hyperirritability, and peripheral neuropathy. Why is he experiencing fatigue?
He has sideroblastic anemia caused by vitamin B6 deficiency
Pt w/anemia has ringed sideroblasts on bone marrow biopsy. Which vitamin deficiency could cause this?