Basic concepts and Blood II Flashcards
IRON TABLETS
- Iron supplements are given to treat iron deficiency
- Iron deficiency can occur
a) During pregnancy
b) Due to excessive blood loss during menstruation or
gastrointestinal bleeding
c) In hook worm infestations
d) Due to impaired intestinal absorption - Iron deficiency causes hypochromic microcytic
anemia
VITAMIN B12
*The only water soluble vitamin stored in the body
* No plant source
* Can be synthesized by bacterial flora
* Absorption takes place in the ileum
* Absorption requires intrinsic factor
* Required for the maturation of RBCs
* Deficiency causes megaloblastic anemia
* Deficiency of intrinsic factor causes pernicious anemia
FOLIC ACID
- Water soluble vitamin
- Required for maturation of
erythrocytes - Required for synthesis of purines
and pyrimidines - Required for the early development
of neural tube in the fetus
. FOLIC ACID
- Deficiency may be seen in
– pregnancy, lactation due to increased
requirement
– impaired absorption in the intestine
– alcoholism
– treatment with drugs that inhibit
dihydrofolate reductase (eg: methotrexate) - Deficiency causes megaloblastic anemia
- Deficiency in pregnant women causes
neural tube defects (spina bifida) in the
fetus
SULFONAMIDES
- Drugs that are structural analogs of PABA
- PABA is a component of tetrahydrofolate (THF)
Sulfonamides competitively inhibit the
bacterial enzyme dihydropteroate synthetase
↓
Decrease the synthesis of folic acid by bacteria
↓
Decrease the availability of THF for the
biosynthesis of purine and pyrimidine nucleotides
↓
Decrease in rate of DNA synthesis
↓
Decreased proliferation of bacterial cells
↓
Used to treat bacterial infections
. METHOTREXATE
- Used to treat cancer
Drug that inhibits the reduction of
dihydrofolate to tetrahydrofolate (THF)
catalyzed by dihydrofolate reductase
↓
Decreases the amount of THF available for
purine and pyrimidine biosynthesis
↓
Inhibits replication in mammalian cells
↓
Decreases the proliferation of cancer cells
MENADIONE
- Synthetic form of vitamin K
Vitamin K - Is a fat soluble vitamin
- Is synthesized by intestinal bacteria in minute quantities
- Is stored in the liver
- Is required for maturation of clotting factors.
- Vitamin K is a coenzyme for γ-carboxylation of glutamate
residues (post translational modification) in clotting factors
prothrombin(II), VII, IX and X , which is required for their further
activation. - Deficiency can occur in newborns since their intestine is sterile
and leads to hemorrhagic disease - Deficiency leads to delayed blood clotting.
WARFARIN
- Is a vitamin K antagonist
- Vitamin K is required for maturation of
clotting factors. - Warfarin inhibits vitamin K dependent γ-
carboxylation of clotting factors, thereby
preventing blood clotting - It is clinically used for preventing
thrombosis and embolism in patients
who have had myocardial infarction,
stroke or heart valve replacement
CYANIDE
- It is highly toxic
- Inhibits cytochrome oxidase (complex IV)
of electron transport chain - Therefore inhibits oxidative
phosphorylation (ATP synthesis) - Can damage the brain and cause death
SODIUM AZIDE
- Inhibits complex IV of electron transport
chain - Inhibits ATP synthesis
- Is used as a preservative in the
laboratory
PORPHYRIA CUTANEA TARDA
- Porphyria cutanea tarda (PCT) is
recognized as the most prevalent
subtype of porphyria - Due to deficiency of uroporphyrinogen
decarboxylase, involved in heme
synthesis. - There is excretion of high quantities of
uroporphyrin in urine giving it an
orange-red fluorescence
The disease is characterized by photosensitivity
(blistering of the skin in areas exposed to sunlight) due
to high levels of porphyrins in peripheral blood
FAVA BEANS
- Staple food in the Mediterranean region
- Patients with Mediterranean variant of G6PD
develop hemolytic anemia if they consume fava
beans (favism) - Deficiency of glucose 6-phosphate
dehydrogenase (G6PD) leads to loss of
membrane integrity in RBCs leading to
hemolytic anemia
