Lecture 33 + 34

Question 1

About Vit C (Ascorbic acid)

Answer 1

water soluble vitamin

help with connective tissue (collagen synthesis and wound healing)
assist the enzymes prolyl and lysyl hydroxylase for collagen stability by H-bond formation

helps with the absorption of Iron (ferrous state)
low vit C = microcytic anemia

also antioxidant

Question 2

Vitamin C deficiency

Answer 2

scurvy

perifollicular hemorrhages
bleeding gums
loose teeth 
bleeding into joints
bruising 
impaired wound healing  

connective tissue defect; less H-bonds

Question 3

Vitamin B1 or thiamine

Answer 3

it is the coenzyme TPP

coenzyme for PDH complex, α-ketoglutarate dehydrogenase, and branched chain α-keto acid dehydrogenase

transketolase needs B1 for PPP

B1 supplementation is used in MSUD (BCKAD)

Question 4

Vitamin B2 or riboflavin

Answer 4

coenzyme forms are FMN and FAD

needed for succinate dehydrogenase, PDH, acyl CoA DH

Question 5

Riboflavin deficiency (B2)

Answer 5

facial dermatitis
glossitis
cheilosis (cracks at edges of mouth)

Question 6

Vitamin B3 or Niacin

Answer 6

coenzyme forms are NAD and NADP

NAD: dehydrogenases
NADP: HMP shunt, fatty acid and cholesterol synthesis

can be used to inhibit tissue lipolysis and reduces fatty acids in the blood in those with Type IIb
hyperlipoproteinemia

Question 7

Niacin deficiency

Answer 7

pellagra: dermatitis, diarrhea, dementia

Question 8

lab tests to show low B1

Answer 8

low RBC transketolase activity

serum thiamine levels

Question 9

tryptophan and NAD

Answer 9

tryptophan 50% of the time forms NAD and NADP

deficiency in tryptophan = less NAD and NADP

Question 10

risk factors for niacin deficiency

Answer 10

corn based diets (not so common anymore)

Hartnup disease (lower absorption of Tryptophan

carcinoid syndrome (excessive tryptophan to serotonin conversion

Question 11

Biotin is important for?

Answer 11

carboxylation reactions

coenzyme for:
pyruvate carboxylase
acetyl CoA carboxylase
propionyl CoA carboxylase

Question 12

Multiple carboxylase deficiency

Answer 12

defect in the corporation of biotin into certain enzymes

impaired gluconeogenesis
hair loss
dermatitis
high propionate levels

Question 13

avidin

Answer 13

seen in egg whites

a known inhibitor of biotin absorption

Question 14

Vitamin B6 or pyridoxine

Answer 14

needed for transamination of AA’s (aminotransferases)

needed for amino acid decarboxylation (AA decarboxylases)

needed for heme synthesis (ALA synthase)

needed for homocysteine metabolism (cystathionine synthase)

Question 15

what can be given to those with Homocystinuria

Answer 15

B6 supplements

Question 16

B6 deficiency

Answer 16

microcytic anemia
peripheral neuropathy
increased cardiovascular disease risk
seizures in infants

Question 17

Vitamin B12 or cobalamin

Answer 17

needed for: 
methionine synthase (needed for DNA synthesis and can lead to folate trap when deficient)

methylmalonyl CoA mutase:
elevated methylmalonyl during deficiency (neurological symptoms)

Question 18

deficiency of vit B12

Answer 18

lack of intrinsic factor, after bariatric surgery, ileac disease

macrocytic megaloblastic anemia
neuropsychiatric symptoms

Question 19

important of folic acid

Answer 19

key role in one-carbon metabolism

used for DNA synthesis

elevated homocysteine levels when methionine synthase is deficient

Question 20

folic acid deficiency

Answer 20

Macrocytic megaloblastic anemia
Macrocytes in peripheral blood smear
Megaloblasts in bone marrow

Question 21

Treatment of megaloblastic anemia

Answer 21

combination of folic acid and Vit B12