Choudhury's DSA- just the bolded stuff.

Question 1

Where does the Iron Come From? 2 major types

Answer 1

•	Primarily from the diet----
•	Two major types of Fe: 
o	Heme (approx. 20% absorbed)
o	Nonheme (approx. 1-2% absorbed)

Question 2

Nonheme Iron (Dietary) absorption

Answer 2

reduced by ferric reductase
DMT1 cotransports Fe +2 into cell
ferroportin exports
transferrin transports to body tisses

Question 3

Heme Iron absorption

Answer 3

endocytosis
heme oxygenase splits
enterocytes convert Fe+3 to Fe+2
then same as nonheme ireon

Question 4

Hemochromotosis

Answer 4

high level of Fe

Question 5

hemosiderin.

Answer 5

• If the storage capacity of the ferritin is exceeded, iron will deposit adjacent to the ferritin-iron complexes in the cell.
• Histologically these amorphous iron deposits are referred to as hemosiderin.

Question 6

apoferritin

Answer 6

circulating Fe is primarily deposited in the liver and spleen (reticuloendothelial system or RES) by binding to the protein apoferritin to form ferritin (the storage form of iron)
• Apoferritin has been called the “iron buffer system” because it can take up excess circulating iron for storage or release iron when circulating levels are too low… therefore maintaining a constant serum iron level

Question 7

bronze diabetes

Answer 7

the bronze skin pigmentation seen in hemochromatosis, coupled with the resultant diabetes lead to the designation of this condition as bronze diabetes.

Question 8

porphyrias

Answer 8

• Disorders that arise from defects in the enzymes of heme biosynthesis

The porphyrias are both inherited and acquired disorders in heme synthesis.

Question 9

where can hyperbilirubinemia come from?

Answer 9

• Inherited disorders in bilirubin metabolism

Question 10

X-linked sideroblastic anemia, XLSA

Answer 10

Enzyme defect: δ-aminolevulinic acid synthase 2, ALAS2

symptom: progressive iron accumulation, fatal if not treated

Question 11

Congenital erythropoietic porphyria, CEP (Gunther disease)

Answer 11

enzyme defect: uroporphyrinogen III synthase

Primary symptom: photosensitivity

Question 12

Erythropoietic protoporphyria, EPP

Answer 12

enzyme defect: ferrochelatase

Primary symptom: photosensitivity

Question 13

ALA dehydratase deficient porphyria, ADP

Answer 13

enzyme defect: ALA dehydratase: also called porphobilinogen synthase

Primary symptom: neurovisceral

Question 14

Hereditary coproporphyria, HCP

Answer 14

enzyme defect: coproporphyrinogen-III oxidase

Primary symptom: neurovisceral, some photosensitivity

Question 15

Acute intermittent porphyria, AIP

Answer 15

enzyme defect: PBG deaminase: also called hydroxymethylbilane synthase or rarely uroporphyrinogen I synthase

Primary symptom: neurovisceral

Question 16

Variegate porphyria, VP

Answer 16

enzyme defect: protoporphyrinogen-IX oxidase

Primary symptom: neurovisceral, some photosensitivity

Question 17

Porphyria cutanea tarda type I, PCT type I, also called the sporadic type PCT

Answer 17

enzyme defect: hepatic uroporphyrinogen decarboxylase

Primary symptom: photosensitivity

Question 18

Porphyria cutanea tarda type II, PCT type II, also called the familial type PCT, may also be referred to as hepatoerythropoietic porphyria, HEP

Answer 18

enzyme defect: uroporphyrinogen decarboxylase in non-hepatic tissues

Primary symptom: photosensitivity, some neurovisceral

Question 19

Characteristic of B6 deficiency

Answer 19

reduction in measurable ALAs product aond protoporphyrin

• -> loss of heme production
• -> ringed sideroblasts, increased serum and intracellular iron concentration –> increased translation of ferritin

Question 20

Iron Deficiency

Answer 20

increase in measureable protoporphyrin; loss of iron intake means reduced iron in the serum and reduced intracellular iron, the latter resulting in reduced ferritin translation;

–> spontaneous, non-enzymatic incorporation of Zn2+ forming Zn-protoporphyrin (ZPP),

Question 21

Heavy Metal Poisoning

Answer 21

inhibit several enzymes of heme biosynthesis and metabolism with the most significant toxic effects resulting from inhibition of ferrochelatase, the enzyme that incorporates iron into protoporphyrin IX generating heme;

• -> increased intracellular iron in bone marrow erythroblasts
• -> ringed sideroblasts
• -> increased delta-ALA and protoporphyrin, increased serum and intracellular iron concentrations, –> increased ferritin synthesis

loss of iron –> ZPP

Question 22

Thalassemias–> what on peripheral smear?

Answer 22

microcytic hypochromic anemia with prominent target cells on peripheral smear

Question 23

In macrophage, porphyrin ring is broken down by

Answer 23

heme oxidase (heme oxygenase)

Question 24

deoxyhemoglobin

Answer 24

reduced hemoglobin

Question 25

oxyhemoglobin

Answer 25

hemoglobin carrying oxygen. Can be measured via pulse oximetry

Question 26

methemoglobin

Answer 26

when Fe2+ is oxidized to Fe3+, methemoglobin is formed and is incapable of binding oxygen

Question 27

methemoglobin reductase

Answer 27

converts methemoglobin back to hemoglovin

Question 28

sulfhemoglobin

Answer 28

oxidized, partially denatured hemoglobin which may result in RBC destruction & hemolysis. Usually due to sulfur-containing drugs (sulfonamides) or aromatic amine drugs (phenacetin, etc.) Cannot carry O2.
** Usually nephrotoxic and will damage the kidneys

Question 29

• Carboxyhemoglobin

Answer 29

hemoglobin carrying CO produced during heme degradation to bilirubin. CO is eliminated via respiration Can also be formed due to CO poisoning