Page 45 - Color Atlas Of Pathophysiology (S Silbernagl Et Al, Thieme 2000)

A. Anemias Caused by Disorders of DNA Synthesis
Folate B 12 deficiency in
B 12
Folate–Glu–Glu... Folate deficiency Cobalamine food (<3µg/d)
in food (vitamin B 12 )
(<50µg/d) Stomach Gastrectomy,
Folate atrophic
gastritis, etc.
Me–H 4 –folate IF Intrinsic 4
factor
Malabsorption Bacteria,
broad tape-
Mucosal cell worm
(jejunum)
Metho-
trexate Gut resection, Megaloblastic Anemia
Duodenum Terminal ileitis
Folate ileum
1 Me–H 4 –folate
B 12
Glu–Glu...
Pteroylpoly- Receptor of
glutamate ileum mucosa
hydrolase
TC-II defect Plate 3.4
TCIII TCII TC I
Folate deficiency
H
H 2 N N N Plasma
CH 2
HN 5 H
N CH 2 Plasma
‘store’
O CH 3 N R Liver
Storage
H (3 – 5 mg) and
5
N -methyltetrahydrofolate excretion Cobalamine
Homocysteine deficiency
Methionine 2 Methylcobalamine B 12
Cellular metabolism
H
N
Serine CH 2 NADP
H Aminopterin,
N CH 2 Dihydrofolate methotrexate
Glycine H reductase
HN R +
H Tetrahydrofolate NADPH+H Impaired folate
N H metabolism
CH 2 3 Fluoruracil N
5 H 8 7 CH 2
N CH 2
10 Fluordesoxy- N CH 2
H 2 C N R uridylate
HN R Erythroblast
10
5
N ,N -Methylen- 7,8-Dihydrofolate
tetrahydrofolate
Thymidylate Desoxy-
synthase DNA synthesis
Desoxyuridylate thymidylate 35
Silbernagl/Lang, Color Atlas of Pathophysiology © 2000 Thieme
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