DD - Ultraviolet Damage and Repair Flashcards Preview

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Flashcards in DD - Ultraviolet Damage and Repair Deck (32):
1

The UV spectrum is divided into (3)

UV-C (100 - 280 nm)
UV-B (280 - 320 nm)
UV-A (320 - 400 nm)

2

The _____ radiation is responsible for most of
the effects of sunlight on the body.

UV-B

3

UVR damage to skin includes

1) damage to DNA, RNA, lipids and proteins
2) pro-inflammatory effects
3) Immunosuppressive effects
3) induction of innate defenses
4) induction of apoptosis
5) Vitamin D synthesis

4

The main types of DNA damage resulting from UVR are?

-Thymine dimer (cyclobutane pyrimidine dimer) (UVB)

-Pyrimidine-6-4 pyrimidone (UVB)

-Hydroxyguanosine (UVA and singlet oxygen)

5

Melanoma
Non-melanoma Skin Cancer
Basal Cell Carcinoma
Squamous Cell Carcinoma

These are all?

ancers caused by UVR

6

Skin Defenses Against UVR

-DNA Repair
-Apoptosis of Cells with DNA Damage
-Defenses Against Reactive Oxygen
-Melanin

7

DNA repair process:

Excision of mutated strand of DNA
UVR ABC nuclease
Repair replication: DNA Polymerase
Rejoining: DNA Ligase

8

4 key enzymes are expressed in skin that help to detoxify free radical damage....

-Peroxidases and catalases
-Superoxide dysmutase
-Glutathione reductase
-Thioredoxin reductase

9

Situated in the basal layer of the skin
Deposit melanin into keratinocytes
One per 5 - 10 basal keratinocytes

Melanocytes

10

The paradox of ultraviolet light therapy for skin diseases

-Treatment of extensive psoriasis, atopic dermatitis
-Cutaneous T cell lymphoma
-Mastocytosis
-Repigmentation of vitiligo

11

SPF Sun Protective Factor refers to

UVB rating

12

-Damage to DNA, RNA, lipids, proteins
-Pro-inflammatory effects
-Immunosuppressive effects
-Induction of innate defenses
-Induction of apoptosis
-Vitamin D synthesis

UVR Effects on the Skin

13

UVR induces the non-enzymatic synthesis of cholecalciferol (VitD3) and _______

ergocalciferol (VitD2)

14

Outcome of DNA Damage

- Repair of Damage
- Induction of Apoptosis
- Gene Mutation

Carcinogenesis initiation, transformation and progression

15

Erythema, sunburn cells, potentiation of other types of cutaneous inflammation are?

UVR Proinflammtory effects

16

UVR induces the non-enzymatic synthesis of __________ and ergocalciferol (VitD2

cholecalciferol (VitD3)

17

UVR decrease in _______ populations

Langerhans Cell

18

Xeroderma Pigmentosum is a family of diseases in which genetic defects in _____

lead to premature aging of the skin and fatal induction of UVR-induced skin cancers

DNA repair

19

UVR Immunosuppression

Not inhibited by high melanin content
Potentiates induction of NMSC

20

DNA Ligase

DNA Repair Enzymes
Rejoining

21

DNA Polymerase

DNA Repair Enzymes
replication

22

Photodermatoses

a skin disease that is caused by exposure to sunlight.

skin rashes following exposure to the sun. Polymorphous Light Eruption is the most common type of photodermatosis.

23

Photodermatoses

Connective Tissue Disease

Lupus Erythematosus
Dermatomyositis
Mixed Connective Tissue Disease (MCTD or Sharp’s Syndrome)

24

Photodermatoses

-Idiopathic probably immunologic
Solar urticaria, PMLE, actinic prurigo
-DNA repair Defects
Xeroderma pigmentosum
-Chemical photosensitivity
Drug induced
Porphyria
-Photoaggrevated dermatoses
Psoriasis
Atopic Dermatitis

25

Humans and mice: Oculocutaneous Albinism (OCA)

-OCA I: Tyrosinase
-OCA II: Pink
-OCA III: Tyrp 1
-OCA IV: MATP

26

UVR ABC nuclease

Excision of mutated strand of DNA
DNA Repair Enzymes

27

-Apoptosis of Cells with DNA Damage
-DNA Repair
-Defenses Against Reactive Oxygen
-Melanin

Skin Defenses Against Ultraviolet Radiation

28

Not inhibited by high melanin content
Potentiates induction of NMSC

UVR Immunosuppression

29

UVR decrease in Langerhans Cell populations by

migration

30

- Repair of Damage
- Induction of Apoptosis
- Gene Mutation

Carcinogenesis initiation, transformation and progression

Outcome of DNA Damage

31

-Thymine dimer (cyclobutane pyrimidine dimer) : UVB
-Pyrimidine-6-4 pyrimidone: UVB
-Hydroxyguanosine (UVA and singlet oxygen)

DNA Damage Induced by UVR

32

-Damage to DNA, RNA, lipids, proteins
-Pro-inflammatory effects
-Immunosuppressive effects
-Induction of innate defenses
-Induction of apoptosis
-Vitamin D synthesis

UVR Effects on the Skin