2 - 17 - CUTANEOUS PHOTOBIOLOGY

Question 1

shortest wavelength of solar electromagnetic radiation reaching the earth’s surface

Answer 1

290 nm

Question 2

carries sufficient photon-energy to completely remove an electron from an atom or molecule (= ionization)

Answer 2

Ionizing electromagnetic radiation, like, for example, x-rays or gamma rays

Question 3

able to move an electron to a higher energy state, but, in contrast to ionizing radiation, cannot remove an electron from atoms or molecules

Answer 3

Nonionizing radiation, which includes ultraviolet radiation (UVR), visible light, and infrared radiation

Question 4

Answer 4

Question 5

Ultraviolet B wavelength

Answer 5

290 nm-315 nm

Question 5

UVA wavelength

Answer 5

315 nm-400 nm

UVA1: 340 nm-400 nm
UVA2: 315 nm-340 nm

Question 6

Visible light wavelength

Answer 6

400 nm-760 nm

Question 7

a photoproduct of photoexcited 7-dehydrocholesterol

Answer 7

previtamin D3

Question 8

photoproduct of excited DNA

Answer 8

cyclobutane pyrimidine dimer

Question 9

process in which energy from an excited chromophore is transferred to another molecules

Answer 9

photosensitized reaction

Question 10

Upon photoexcitation, a photochemical reaction can occur to form a new, different molecule

Answer 10

photoproduct

Question 11

Question 12

Identify if UVA or UVB:

Immediate erythema

Answer 12

UVA

Question 13

Identify if UVA or UVB:

Delayed melanogenesis (peaks at 3 days)

Answer 13

UVB

Question 13

Identify if UVA or UVB:

Immediate pigment darkening (within 20 minutes after UVR exposure)

Answer 13

UVA

Question 13

Identify if UVA or UVB:

Major role in drug induced photosensitivity; contributes to carcinogenesis

Answer 13

UVA

Question 14

Identify if UVA or UVB:

associated with sunburn

Answer 14

UVB

1000 × more erythemogenic than UVA

Question 15

Identify if UVA or UVB:

Central role in photoaging

Answer 15

UVA

UVB also has a role in photoaging

Question 15

Identify if UVA or UVB:

Major role in carcinogenesis

Answer 15

UVB

Question 15

Identify if UVA or UVB:

Penetrates down to deep dermis

Answer 15

UVA

Question 16

Identify if UVA or UVB:

Not associated with vitamin D production

Answer 16

UVA

Question 17

Identify if UVA or UVB:

Penetrates no deeper than the upper dermis

Answer 17

UVB

Question 18

Identify if UVA or UVB:

Role in vitamin D production

Answer 18

UVB

Question 19

Identify if UVA or UVB:

Penetrates window glass

Answer 19

UVA

Question 20

# Identify if UVA or UVB: Immunosuppression

Answer 20

BOTH

Question 21

sunburn typically peaks how many hours after sun exposure?

Answer 21

6 to 24 hours

Question 22

tanning peaks approximately how many days after UVB exposure?

Answer 22

3 days

Question 23

chromophore for UVR-induced tanning, very similar to erythema formation

Answer 23

DNA

Question 24

# Identify the skin phenotype * Always burns, never tans * Pale white

Answer 24

I

Question 25

This is the lowest dose that causes erythema in an individual

Answer 25

minimal erythema dose

Question 26

# Identify the skin phenotype * Rarely burns, tans easily * Brown; moderately pigmented

Answer 26

V

Question 27

# Identify the skin phenotype * Sometimes burns, can tan without prior burn * White

Answer 27

III

Question 28

# Identify the skin phenotype * Burns only with very high UVR doses, tans * Dark brown to black; darkly pigmented

Answer 28

VI

Question 29

# Identify the skin phenotype * Usually does not burn, tans easily and deeply * White to light brown

Answer 29

IV

Question 30

# Identify the skin phenotype * Always burns, then tans * White

Answer 30

II

Question 31

Photo-phytodermatitis is a phototoxic reaction mediated by plant-based chromophores, namely what?

Answer 31

furocoumarins

Question 32

Berloque dermatitis is also a phototoxic dermatitis, in which the chromophore is what perfume ingredient?

Answer 32

bergamot oil (5-methoxy psoralen)

Question 33

the chromophore that mediates the antipsoriasis therapeutic efficacy

Answer 33

DNA

Question 34

absorption maximum of DNA

Answer 34

260 nm

Question 35

UV signature mutations

Answer 35

C → T and the C:C → T:T tandem mutations at dipyrimidine sites

Question 36

most of the oxidative DNA damage after exposure to natural sunlight is caused by which UVR

Answer 36

UVA

Question 42

The only nonproliferative feature of photoaged skin that is not observed in intrinsically aged skin

Answer 42

Actinic elastosis

Question 43

The only positive effect of UVR on skin

Answer 43

vitamin D production