DD - Ultraviolet Damage and Repair Flashcards

1
Q

The UV spectrum is divided into (3)

A

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

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2
Q

The _____ radiation is responsible for most of

the effects of sunlight on the body.

A

UV-B

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3
Q

UVR damage to skin includes

A

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

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4
Q

The main types of DNA damage resulting from UVR are?

A
  • Thymine dimer (cyclobutane pyrimidine dimer) (UVB)
  • Pyrimidine-6-4 pyrimidone (UVB)
  • Hydroxyguanosine (UVA and singlet oxygen)
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5
Q

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

These are all?

A

ancers caused by UVR

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6
Q

Skin Defenses Against UVR

A
  • DNA Repair
  • Apoptosis of Cells with DNA Damage
  • Defenses Against Reactive Oxygen
  • Melanin
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7
Q

DNA repair process:

A

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

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8
Q

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

A
  • Peroxidases and catalases
  • Superoxide dysmutase
  • Glutathione reductase
  • Thioredoxin reductase
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9
Q

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

A

Melanocytes

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10
Q

The paradox of ultraviolet light therapy for skin diseases

A
  • Treatment of extensive psoriasis, atopic dermatitis
  • Cutaneous T cell lymphoma
  • Mastocytosis
  • Repigmentation of vitiligo
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11
Q

SPF Sun Protective Factor refers to

A

UVB rating

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12
Q
  • Damage to DNA, RNA, lipids, proteins
  • Pro-inflammatory effects
  • Immunosuppressive effects
  • Induction of innate defenses
  • Induction of apoptosis
  • Vitamin D synthesis
A

UVR Effects on the Skin

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13
Q

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

A

ergocalciferol (VitD2)

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14
Q

Outcome of DNA Damage

A
  • Repair of Damage
  • Induction of Apoptosis
  • Gene Mutation

Carcinogenesis initiation, transformation and progression

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15
Q

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

A

UVR Proinflammtory effects

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16
Q

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

A

cholecalciferol (VitD3)

17
Q

UVR decrease in _______ populations

A

Langerhans Cell

18
Q

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

A

DNA repair

19
Q

UVR Immunosuppression

A

Not inhibited by high melanin content

Potentiates induction of NMSC

20
Q

DNA Ligase

A

DNA Repair Enzymes

Rejoining

21
Q

DNA Polymerase

A

DNA Repair Enzymes

replication

22
Q

Photodermatoses

A

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
Q

Photodermatoses

A

Connective Tissue Disease

Lupus Erythematosus
Dermatomyositis
Mixed Connective Tissue Disease (MCTD or Sharp’s Syndrome)
24
Q

Photodermatoses

A
-Idiopathic probably immunologic
Solar urticaria, PMLE, actinic prurigo
-DNA repair Defects
		Xeroderma pigmentosum
-Chemical photosensitivity
		Drug induced
		Porphyria
-Photoaggrevated dermatoses
		Psoriasis
		Atopic Dermatitis
25
Q

Humans and mice: Oculocutaneous Albinism (OCA)

A
  • OCA I: Tyrosinase
  • OCA II: Pink
  • OCA III: Tyrp 1
  • OCA IV: MATP
26
Q

UVR ABC nuclease

A

Excision of mutated strand of DNA

DNA Repair Enzymes

27
Q
  • Apoptosis of Cells with DNA Damage
  • DNA Repair
  • Defenses Against Reactive Oxygen
  • Melanin
A

Skin Defenses Against Ultraviolet Radiation

28
Q

Not inhibited by high melanin content

Potentiates induction of NMSC

A

UVR Immunosuppression

29
Q

UVR decrease in Langerhans Cell populations by

A

migration

30
Q
  • Repair of Damage
  • Induction of Apoptosis
  • Gene Mutation

Carcinogenesis initiation, transformation and progression

A

Outcome of DNA Damage

31
Q
  • Thymine dimer (cyclobutane pyrimidine dimer) : UVB
  • Pyrimidine-6-4 pyrimidone: UVB
  • Hydroxyguanosine (UVA and singlet oxygen)
A

DNA Damage Induced by UVR

32
Q
  • Damage to DNA, RNA, lipids, proteins
  • Pro-inflammatory effects
  • Immunosuppressive effects
  • Induction of innate defenses
  • Induction of apoptosis
  • Vitamin D synthesis
A

UVR Effects on the Skin