Vitamins Flashcards
Folic acid supplementation
0.4 mg/day or 400 micrograms/ day
During time of conception
MCV of micro and macrocytic anemias
Normal MCV: 80-100
If less than 80, micro
If more than 100, macro
Cobalamin
Aka vitamin B12
When will the CNS effects of Vit b12 deficiency resolve?
The CNS effects are irreversible
High dose oral Vit B12 or IM cyanocobalamin given for life
Active form of vitamin c
Ascorbate acid
Main function of ascorbate
Reducing agent
Vit B12 is required for what 2 essential enzymatic reactions
- Synthesis of methionine
2. Isomerization reactions (methylmalonyl CoA –> succ CoA)
Diagnosis of pernicious anemia
Schilling test
Parasite than can cause megaloblastic anemia
D. Latum
Ingestion of undercooked/ uncooked fish
Spongy gums, loose teeth, fragile blood vessels, swollen joints, anemia
Scurvy
Functions of Vitamin c
Maintenance of normal connective tissue, wound healing, absorption of dietary iron
Antioxidants
Vitamin C
Vitamin E
B- Carotene
Biologically active Vit B6
Pyridoxal phosphate
Pyridoxal phosphate used as coenzyme for:
AA transamination Glycogen phosphorylase Cystathione synthase ALA Synthase Synthesis of niacin from tryptophan
How does INH cause Vit B6 deficiency
By forming an inactive derivative with pyridoxal phosphate
Vitamin B6 toxicity
More than 2 g/day
Presents with gait problems, seizures
Biologically active form of Vit B1
Thiamine pyrophosphate (TPP)
Vitamin B1 deficiency
Beri-beri
Wernicke-Korsakoff
Wernicke’s encephalopathy
Weird ACO
Ataxia - leg tremor
Confusion
Ophthalmoplegia - nystagmus, problem with EOMs, double vision, eyelid dropping
Korsakoff syndrome
Korny si CHA
Confabulation - making up stories because one doesn’t remember
Hallucinations
Amnesia - anterograde
Thiamine used as cofactor for
Pryruvate
Alpha ketoglutarate
Branched chain AA dehydrogenase
Transketolase reactions in HMP shunt
Pellagra
Dermatitis
Dementia
Diarrhea
Death
Niacin deficiency (B3)
Effect of niacin on fat
In adipose, strongly inhibits lipolysis
In liver, decreases triacylglycerol synthesis
Increases HDL levels
Lowers TAG, LDL, VLDL
ADR: flushing, hyperuricemia
Drugs that cause flushing: VANC
Vancomycin, adenosine, niacin, CCBs
Niacin can be derived from what AA
Tryptophan
Requires Vit b6
Hartnup disease
Decreased tryptophan absorption
Active forms of niacin
NAD+
NADP+
Active forms of vitamin B2
FMN - flavin mononucleotide
FAD - flavin adenine dinucleotide
Both can accept two hydrogen atoms each
Dermatitis, cheilosis, glossitis, corneal vascularization, stomatitis
Vit b2 deficiency
Glossitis - tongue appearing smooth and purplish
Cheilosis - fissuring at corners of the mouth
Stomatitis - inflammation of oral mucosa
Biotin is a coenzyme for?
Carboxylation reactions
What food can induce symptoms of biotin deficiency
Raw egg white
Contains AVIDIN which tightly binds biotin, preventing its absorption from the intestines
Vitamin that is a component of fatty acid synthase
Vitamin b5
Essential functions of vitamin A
Vision
Reproduction
Growth
Maintenance of epithelial tissue
What form of vitamin A mediates vision
Retinal
Other reactions are mediated by retinoic acid
Physiology: What substance directly stimulates rods?
Metarhodopsin II
Where is vitamin A stored?
Liver. Ito cells
Earliest sign of Vitamin A deficiency
Nyctalopia
Severe vitamin A deficiency leads to?
Xerophthalmia
Xerophthalmia
Pathologic dryness of conjunctiva and cornea
May lead to corneal ulceration and blindness (formation of opaque scar tissue)
Form of vitamin A used in treatment of dermatologic problems
Retinoic acid
Tretinoin (all trans retinoic acid) –> treatment also for APML
Isotretinoin (oral)
Teratogenic effect of vitamin a
Craniofacial anomalies
Ergocalciferol
Vitamin D2 - found in plants
Cholecalciferol
Vitamin D3 - found in animals
Major storage form of vitamin D
25–OH D3 (after first hydrolyation in the liver)
Also the most predominant form in plasma
Most potent vitamin D metabolite
1,25-di-OH D3
Overall function of 1,25-diOH D3
To maintain plasma levels of calcium
What secretes PTH
Chief cells of parathyroid gland
What secretes calcitonin
Para follicular/ C cells of thyroid gland
Continued formation of collagen matrix of bone but incomplete mineralization, resulting in soft pliable bones
Rickets
Demineralization of preexisting bone, increasing susceptibility to fractures
Osteomalacia
Most toxic vitamin
Vitamin D
Principal role of vitamin K
Post-translational modification of various blood clotting factors
Why do we give vitamin K to newborns
They have sterile bacteria and cannot initially synthesize vitamin K
Vitamin K dependent factors
1972
Protein c, s
After how many hours does warfarin have anti-coagulative effects
Within first 48-72 hrs, predominant effect is inhibition of protein C and S (promotes coagulation) –> necrosis
After 72 hrs, starts to exert anti-coag effect
Therefore, make sure to overlap with heparin in the first 3 days
Most active vitamin E
Alpha tocopherol
Primary function of vitamin e
Antioxidant
Least toxic of fat soluble vitamins
Vitamin E
Active form of folic acid
Tetrahydrofolate
What is the effect of vitamin D deficiency on calcitonin
Low vitamin D deceases secretion of calcitonin
Does vitamin K increase or decrease coagulation time?
Vitamin K decreases coagulation time
Earliest manifestation of megaloblastic anemia
Hyper segmentation of neutrophils (more than 5)
Normal: 3-5
Vitamin that is a component of coenzyme A
Pantothenic acid (Vit B5)
