General Pathology

1
General Pathology

• Basic Principles of Cellular and Organ Pathology
• Autogenous Pigments

Jaroslava Dušková Inst. Pathol. ,1st Med.
Faculty, Charles Univ. Prague
2
Pigments

• Definition
• colored substances
• in the organism
• or environment

3
Pigments

• Classification
• endogenous
• autogenous
• hemoproteins derived
• exogenous

4
Autogenous Pigments

• - color substances formed in the organism as
  metabolism products
• melanin
• ceroid
• lipofuscin

5
Melanin

• oculocutaneous
• (origin from tyrosine in melanocytes)
• neuromelanin - subst. nigra
• (origin from dopamin)

6
Melanin - types

• eumelanin insoluble , brown-black
• phaeomelanin soluble, yellow-red (high
  sulphur content)

7
Melanin - production

• Melanocytes
• derived from the neural crest
• present in the basal layer of epidermis, dermis,
  hair folicles, mucose membranes, uveal tract of
  the eye, meninges, inner ear
• secretory in the contact with the epithelial
  cells - cytocrinia

8
Melanin Functions 1.

• cytoprotective
• light absorption conversion of the photon
  energy into heat
• uvea absorption of the light retina
  protection of light overexposure
• retina - visual acuity preventing light
  reflexion from the fundus

9
Melanin Functions -2.

• Ion exchanging capacity
• Melanosomes can also act as detoxyfiing and
  excretory components accumulating great number of
  drugs and toxic component e.g. heavy metals.
• Scavengers of the free radicals.
• Rarely cytotoxic photosensibilisation

10
Melanin - Features

• brown
• destained with H2O2
• reducing AgNO3

11
Disorders of Melanin Pigmentation

• Lack
• generalized
• total albinism
• parcial albinism

• local
• vitiligo
• leucoderma

12
Albinism

• autosomal recessive heredity
• tyrosinase deficiency
• tyrosinase positive melanosomes defect
• oculo-cutaneous albinoidism dominant
  inheritance

13
Disorders of Melanin Pigmentation

• Lack
• generalized
• total albinism
• parcial albinism

• local
• vitiligo
• leucoderma

14
Vitiligo

• familial aggregation
• polygenic nature
• association with other autoimmune diseases
  (DM, thyroiditis, gastritis)
• ab against tyrosinase in the serum
• autoreact . T- cellular cytotoxicity

15
Disorders of Melanin Pigmentation

• Lack
• generalized
• total albinism
• parcial albinism

• local
• vitiligo
• leucoderma

16
Leucoderma

• postinflammatory circumscribed depigmentation
  e.g.
• leucoderma syphyliticum
• leucoderma psoriaticum

17
Disorders of Melanin Pigmentation

• Increase
• generalized
• Adison disease

• local
• freckles, nevi
• chloasma /melasma
• melanodermia
• melanoma

18
Disorders of Melanin Pigmentation

• Increase
• generalized
• Adison disease

• local
• freckles, nevi
• chloasma
• melanodermia
• melanoma

19
Disorders of Phenylalanine and Tyrosine
Metabolism

• 1. Phenylalanine hydroxylase PHENYLKETONURIA
  
• 2. Homogentisic acid oxydase
• ALKAPTONURIA
• 3. Tyrosinase ALBINISM

20
Disorders of Phenylalanine and Tyrosine
Metabolism
Phenylalanine
Tyrosine
1
3
Homogentisic acid
DOPA
2
cc
methyl acetoacetic acid
MELANIN
Norepinephrine Epinephrine
21
Ceroid

• features
• light brown
• PAS
• acidoresistent
• Sudan -
• origin
• fagocytosis od lipid substances by
  macrophages
• oxidation of nonsaturated lipid acids

22
Ceroid

• localisation
• places of erythrocytes destruction
• necroses of adipous tissue
• avitamonosis E
• melanosis coli
• Dubin - Johnson syndrome

23
Lipochrom

• ubiquitous pigment
• exogenous origin
• lipid solvent
• histologically unprovable

24
Lipofuscin

• features
• dark brown
• Sudan -
• autofluorescence

25
Lipofuscin

• origin
• autophagocytosis
• "wear and tear" pigment
• from the accumulation
• of autophagolysosomes over time.

26
Lipofuscin

• localisation
• CNS, epithels, muscles, liver
• ATROPHIA FUSCA