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Flashcards in module 5 defective hemoglobin synthesis Deck (54):
1

sideropenic anemia

Also known as IDA. inadequate uptake or absoprtion, blood loss. responds to iron therapy.

2

anemia chronic disease

defective iron metabolism iron kept in macrophages.

3

duodenal cytochrome b

DcytB. Reduces ferric iron to ferrous at brush border.

4

Divalent Metal Transport

Transports ferous iron across the apical enterocyte plasma membrane.

5

iron stored in enterocyte

can be as ferritin which is lost when sloughed off, or transported into across baolateral side

6

ferroportin

transports iron across basolateral side of enterocyte.

7

Hephaestgin

facilitates basolateral transport of iron by oxidizing to ferric form.

8

transferrin

plasma iron protein which mediates iron exchange between tissues. negative acute phase reactant. levels decrease during acute phase response.

9

apotransferrin

transferrin with no bound iron.

10

Total Iron binding capacity

the total amount of iron which can be bound by transferrin.

11

Iron delivered to transferrin comes from:

monocyte macrophage recycing. A small pefrcentage comes from absorption. Delivered to developing macrophages.

12

Transferrin receptor

found on cells. Binds transferrin and grabs iron. Expression correlates with iron requirements.

13

Transferrin mechanism of action

transferrin - iron binds tfr. clusters invaginates forms endosome. Iron released, transported into cytoplasm. both proteins not degraded but recycled.

14

soluble transferrin receptor

Extracelluar portion of tFR released as cell matures. Increased sFTR increases as erythropoesis increases.

15

Ferritin

acts as primary iron storage compound. Spherical 24 unit multimer composed of varying numbers of H and L chains. Found in marrow liver and spleen usually in siderosomes. Small amounts can enter plasma through lyisis.

16

Ferritin (reactant)

acute phase reactant. Increases in inflammation or tissue damage. If depleted means stores are depleted.

17

hemosiderin

non specific iron carbs, lipid protein. Found usually in macrophages. Formed after lysosome degradation of ferritin at very high iron levels. Released slowly not readily available for functions.

18

Hepcidin

synthesized in liver. Master iron regulator. decreases iron absorption into the body by binding to and inducing degradation of ferroportin. Also blocks export from macrophages.

19

Hepcidin expression modulated by:

iron stores, erythropoesis, hypoxia, inflamattion / infection.

20

Hepcidin infection

decreased.

21

HFE

competes with transferrin for TFR. Expressed on membrane. Free HFE when TFR bind transferrin signals to increase hepcidin expression.

22

HJV

coreceptor with HFE. HJV mutations decrease hepcidin expression.

23

TIBC < 15%

possible ID

24

TIBC >50%

iron overload possible hemochromatosis.

25

Ferritin in detecting IDA

first sign low ferritin appears before low TIBC. However is an acute phase reactant.

26

SfTR

inversely proportional body iron because receptor level increases when iron is low.

27

ZPP

zinc incorporated into proptoporyphyrin ing in absence of iron. ZPP reflects iron over last several weeks. INcorporated in IDE stage.

28

ferrokientics

labeled iron binds to transferrin, clearance from plasma measured. Can also measure incorporation into RBC (spin down). Most iron incorporated in 10-14 days.

29

PIT

rate plasma leaves iron

30

RCU

red cell utilization of iron ferrokinetics

31

IDA in developing countries

parasitic infection with low iron in diet.

32

IDA from diet alone

only in infacny adolescence, childhood.

33

IDA and blood loss

usually from GI tract ie lesions hemherroids etc.

34

Anemiain kidney disease

lack EPO. rEPO fixes. Iron cannot be mobilized quickly enough can lead to ID. Therefore give iron injection

35

IDA malabsorption

Sprue, gastrectomy, gastritis.

36

Stage 1 ID

decreased serum ferrritin, increased rBC RDW.

37

Stage 2 ID

ZPP becomes present. % transferrin drops. Sftr increased. TIBC increased.

38

Stage 3 ID

microcytic microchromic. All iron tests are low.

39

Pica

common with IDA. ice phagia.

40

IDA blood picture

codocytes, elliptocytes, dacrocytes. RPI <2.

41

differentiate IDA from ACD

sFTR levels doubled for ID, while identical to normal people for ACD. ALso can use serum ferritin, MCV and iron saturation.

42

Differentiate IDA from thalassemia

ZPP levels four times higher in IDA.

43

ACD characterized by

by hypoferremia, decreased transferrin (decreased TIBC), increased serum ferritin, and increased iron in bone marrow macrophages. Block of release from macrophages

44

ACD molecular mechanism

Hepcidin blocks release from macrophages, caused by IL6 and other inflammatory cytokines. IL 6 also blocks EPO production and response.

45

Sideroblastic anemia

mutations in ALAS, first heme pathway protein. by (1) an increase in total body iron, (2) the presence of ring sideroblasts in the bone marrow, and (3) hypochromic anemia.

46

Siderblastic anemia blood work

•Dual population of hypochromic and normochromic erythrocytes •Pappenheimer bodies in erythrocytes •normal or increased platelets •Increased serum iron, serum ferritin, and percentage of saturation •Ring sideroblasts in the bone marrow
Hyperplastic BM RPI < 2.

47

Ferritin : hemosiderin ratio

good indicator of total body iron. When low ferritin is high, when high hemosiderin is high.

48

serum iron

iron bound to transferrin

49

find a sideroblast

stain with prussian blue. iron is usually diffuse in normal blasts.

50

most common causes of sideroblastic anemia

lead and alcohol poisioning

51

HBS pathophysiology

GLU-> Val mutation on surface causes less polar and less soluble in deoxy state. Reversible on oxygenation. Delays means most blood cells do not sickle, but sickle in spleen kidney and other hypoxic acidic environments.

52

ferritin to hemosiderin ratio:

total body iron

53

IDE stage

ZPP incorporated.

54

most common causes acquired SA

alcohol and lead poisoning.