6F: Cell Injury and Adaptation III

Question 1

HIF-1 and diabetic retinopathy

Answer 1

HIF-1 promotes new blood vessel formation in hypoxic conditions. In diabetic retinopathy, this angiogenesis makes things worse because with more blood vessels, the retina gets thicker and it is harder for light to penetrate the cells

Question 2

What is the most common cause of cell necrosis?

Answer 2

Ischemia

Question 3

why is reperfusion bad?

Answer 3

• reperfusion increases the risk of generating ROS

Question 4

apoptosis vs. necrosis

Answer 4

apoptosis: programmed cell death
physiologic causes: developmental morphogenesis, immune system regulation, hormone withdrawal
pathologic causes: genetic damage, misfolded proteins, viral infection 
- does not provoke inflammation
- orderly DNA fragmentation
necrosis: uncontrolled cell death 
- promotes inflammation
- happens all over at once
- unorderly DNA destruction

Question 5

mitochondrial (intrinsic) pathway of apoptosis

Answer 5

• cell injury occurs
• signaling to mitochondria = mitochondrial damage
• mitochondria releases cytochrome C into the cytoplasm
• cytochrome C initiates initiator caspases
• initiator caspases initiate executioner caspases
• executioner caspases start to break down the cell

Question 6

death receptor (extrinsic) pathway of apoptosis

Answer 6

• T-cell activated b/c it recognizes the messed up cell as “non-self”
• T-cell presents ligand to Fas receptor on cell
• Fas activates initiator caspases
• initiator caspases initiate executioner caspases
• executioner caspases start to break down the cell

Question 7

Exogenous Carbon Pigment

Answer 7

Vignette: 
- from inhaling a lot of smoke, possibly living in a big city
- macrophages try to eat the smoke 
Histology: 
- black dots everywhere

Question 8

Mallory Hyaline (“alcoholic hyaline”)

Answer 8

Vignette: 
- usually seen with alcoholics
Histology: 
- ropey looking eosinophilic clumps in the cytoplasm
- usually paired with areas of fat

Question 9

Hemosiderin

Answer 9

Vignette:
- seen in the lung in heart failure cells
Histology:
- aggregates of iron
- use the Prussian Blue reaction and the iron turns blue

Question 10

Lipofuscin (lipochrome) Pigment

Answer 10

Vignette: 
- end result of lipid peroxidation
- no deleterious effect on cells
Histology: 
- yellow pigment
- often in a perinuclear location

Question 11

Melanin Pigment

Answer 11

Vignette: 
- metastatic lesion
- skin biopsy
Histology: 
- can stain with immunoperoxidase
- dark spots in an eosinophilic area
- usually identified with the vignette

Question 12

dystrophic calcification

Answer 12

• calcification that occurs in an abnormal or previously injured cell
• Ca2+ concentration in the serum is normal

Question 13

metastatic calcification

Answer 13

• related to bone metastases, but can occur in any organ or even normal tissue during periods of hypercalcemia
• Ca2+ concentration is high in the serum