Non keratinocytes ppt

seminar

1. V.BHARGAVI P.G I YEAR PERIODONTICS NON -KERATINOCYTES PRESENTED BY

2. CONTENTS INTRODUCTION LANGERHANS CELLS INFLAMMATORY CELLS MERKEL CELLS MELANOCYTES SUMMARY CONCLUSION

3. Introduction THE PRINCIPAL CELL TYPE OF THE GINGIVAL EPITHELIUM, AS WELL AS OF OTHER STRATIFIED SQUAMOUS EPITHELIA, IS THE “ KERATINOCYTE ”. IN ADDITION TO THE KERATIN-PRODUCING CELLS WHICH COMPRISE ABOUT “90%” OF THE TOTAL CELL POPULATION, EPITHELIUM ALSO CONTAINS “ NON-KERATINOCYTES ” (10%).

4. THESE CELL TYPES ARE OFTEN STELLATE AND HAVE CYTOPLASMIC EXTENSIONS OF VARIOUS SIZE AND APPEARANCE THESE NON-KERATINOCYTES ALONG WITH KERATINOCYTES PLAY AN IMPORTANT ROLE, IN THE MAIN FUNCTION OF GINGIVA THAT IS THE “ PROTECTION ” OF UNDERLYING TISSUES.

5. KERATINOCYTES, NON KERATINOCYTES EPITHELIUM

6. KERATINOCYTES: CONTAIN KERATIN FILAMENTS ( CYTOKERATINS ) AS “ TONOFILAMENTS ” AND DESMOSOMES DESMOSOME

7. NON-KERATINOCYTES : NO TONOFILAMENTS AND DESMOSOMES NO ROLE IN MATURATION EPITHELIUM. CLEAR HALO AROUND THEIR NUCLEI, (EXCEPT MERKEL CELLS) “ CLEAR CELLS ” MIGRATE FROM NEURAL CREST OR FROM BONE MARROW . @ TENCATES PAGE 333 ,327

8. Str. basale Str. spinosum Str. granulosum MELANOCYTES, MERKELL CELLS LANGERHANS CELLS A VARIETY OF CELL TYPES ARE INCLUDED IN NON- KERATINOCYTES, THEY ARE. 1)LANGERHAN ’ S CELLS 2)MERKEL CELLS 3)PIGMENT PRODUCING- MELANOCYTES 4)INFLAMATORY CELLS.

9. LANGERHAN ’ S CELLS

10. A DENDRITIC CELL OF INTERSTETIAL SPACES OF MAMMALIAN EPIDERMIS AND MUCOSA THAT FUNCTIONS AS “ ANTIGEN PRESENTING CELL” ,WHICH BINDS ANTIGEN ENTERING THROUGH THE SKIN/MUCOSA AND TRANSPORT IT TO LYMPH NODES.

11. LOCATED AMONG THE KERATINOCYTES, AT SUPRA BASAL LEVEL ( HIGH LEVEL CLEAR CELLS). PROBABLY FOUND TO BE ABSENT FROM JUNCTIONAL EPITHELIUM OF NORMAL GINGIVA. GERMAN ANATOMIST AND PHYSICIAN “ PAUL LANGERHANS ” (1868 VIRCHOWS ARCH PATH ANAT PHYSIO )

12. BELONG TO RETICULO-ENDOTHELIAL SYSTEM , MODIFIED MONOCYTES, DERIVED FROM BONE MARROW. ACT AS SENTINELS (COPS ) IN EARLY DETECTION OF ANTIGENS . RETICULO-ENDOTHELIAL SYSTEM

13. ORIGIN: HEMATOPOETIC ORIGIN, DERIVED FROM BONE MARROW PRE-CURSORS. A SPECIFIC TYPE OF MONOCYTE PROLIFERATES AND DIFFERENTIATES TO FORM LANGERHAN’S CELLS, CSF IS NECESSARY FOR TRANSFORMATION.

14. ENTER THE BLOOD STREAM , FROM BONE MARROW CIRCULATE AND LEAVE THE BLOOD STREAM ENTER LAMINA PROPRIA PENETRATING THE BASAL LAMINA ENTER EPITHELIUM .

15. DRIVING FORCE ARE CHEMOKINES ( MONOCYTE CHEMOATTRACTANT PROTEIN 1) SECRETED BY KERATINOCYTES,HAVING RECEPTORS ON LANGERHAN’S CELLS. APPEAR AT THE SAME TIME OR JUST BEFORE MELANOCYTES, .CAPABLE OF DIVISION

16. STRUCTURE: THEY ARE DENDRITIC - WITH LONG IRREGULAR PROCESSES.

17. ULTRASTRUCTURE : LACK TONOFILAMENTS AND DESMOSOMAL ELEMENT THE NUCLEUS IS CONVULUTED. SMALL ROD/FLASK SHAPED “ BIREBECK GRANULES” NAMED AFTER PERSON WHO FIRST DESCRIBED THEM.(1961) BIREBECK GRANULES NUCLEUS

18. IDENTITY MAKES THE DIFFERENCE !!!!!!!!!!!!

19. STAINING OR IMMUNOHISTO CHEMISTRY : GOLD IMPREGNATTION IS THE CLASSICAL TECHNIQUE USED BY LANGERHANS 100 YEARS AGO, BUT IT REQUIRES DILIGENT PREPARATION. CD1a CELL SURFACE ANTIGEN MARKER , Fc RECEPTOR , S-100 PROTEIN MARKED ATP ACTIVITY AND LOCALISED DUE TO ATPase .

20. Immunohistochemical staining for S-100 protein+ Langerhans ’ cells in the gingival epithelium. @ Dereka XE,J .periodontal research :2004 DEC

21. FUNCTION OF LANGERHANS CELLS ??

22. LANGERHAN ’ S CELLS INGEST ANTIGEN BY MACROPINOCYTOSIS AND VIA A VARIETY OF CELL SURFACE RECEPTOR S(TOLL LIKE RECEPTORS) THEN THEY LEAVE THE EPITHELIUM ENTER LYMPHATICS AND TRAVEL TO PARA CORTEX OF LYMPHNODE . THERE THEY DIFFERENTIATE INTO MATURE DENDRITIC CELLS. THEY ACTIVATE NAIVE T — LYMPHOCYTES BY” MHC II PATHWAY AND RELEASE A VARIETY OF CYTOKINES.

23. MHC ????????????

24. MHC MOLECULE : GROUP OF 6 GENES ON SHORT ARM OF CHROMOSOME 6. PRODUCE ANTIGEN CALLED “HUMAN LEUKOCYTIC ANTIGEN (HLA)” WHICH WILL BE PRESENT ON THE CELL MEMBRANE RECOGNISED AND IDENTIFIED BY THE IMMUNE SYSTEM CELLS, SO THE NAME “ ANTIGEN”. PRESENT ANTIGENIC PIECES OF MICROBES TO T-CELLS. PICTURE 6 GENES MHC NUCLEUS HLA

25. TWO TYPES OF MHC-HLA MOLECULES. MHC-I : FOUND IN ALL NUCLEATED CELLS AND ALSO ON PLATELETS. MHC-II : FOUND IN SPECIALISED ANTIGEN PRESENTING CELLS DENDRITIC CELLS,MACROPHAGES, B CELLS THE DISTRIBUTION IS NECESSARILY DIFFERENT SO AS TO DIRECT T-CELL(TC & TH CELLS) TO CARRY OUT THEIR APPROPRIATE FUNCTION. PIC

26. FOR PRESENTATION BY HLA -…..PEPTIDES TO BE PROCESSED. TWO DIFFERENT PROCESSING PATHWAYS ARE PRESENT THEY ARE 1 ) ENDOGENOUS PATHWAY. (OR ) 2 ) EXOGENOUS WHICH INTURN DETERMINED BY MODE OF ENTRY OF INVADING MICROBES.

27. ENDOGENOUS PATHWAY : VIRAL PEPTIDES ARE ASSEMBLED WITH HLA – I MOLECULES . VIRUS WHICH ENTER CELL PRESENT IN CYTOSOL AND ARE PROCESSED BY CTOPLASMIC ENZYMES,

28. EXOGENOUS PATHWAY : FOR MICROBES WHICH ARE TAKEN BY PHAGOCYTOSIS . FORMED BY PROCESSING OF LYSOSOMAL ENZYMES ARE ASSEMBLED WITH HLA-II MOLECULES

29. AS APC HAVE MHC-II----- EXOGENOUS PATHWAY ACTIVATES CD4+T LYMPHOCYTES ,THESE ARE IMMATURE Th ( (HELPER T-CELLS). WHICH PRODUCE CYTOKINES LIKE IL-2, INF-Γ, WHICH ACTIVATE OTHER T-CELLS LIKE THE CYTOTOXIC T CELLS ----- CELLS KILL PATHOGEN SUPPRESSOR T-CELLS---- PREVENT THE EXCESIVE DESTRUCTION OF HOST OWN CELLS. AFTER ACTIVATION OF OTHER TC AND TH LYMPHOCYTES FEW CELLS BECOME MEMORY T-CELLS,TO REACT IMMEDIATELY FOLLOWING SECOND EXPOSURE.

30. study Cell studied disease Cutler and jotwani ( perio 2000,2004 ) LC PD Jotwani et al ( j.immunol 2001 167) LC PD,GV Myint et al( JCP 2000 27) LC Periodontitis associated with hiv Sohoel et al (EUR J.oral science 1995) LC Marginal periodontitis in downs syndrome Lundquist and Hammerstrom ( Immunology 1993) LC Inflamed gingiva Walsh et al ( J dental research 1985) PUTATIVE LC in health,experimental gingivitis Mostafa eta l( ( Virchows Arch A Pathol Anat Histopatho;l 1993) LC verruciform xanthoma of gingiva PERIO 2000;2004 VOL 35

31. PERIODONTAL IMPLICATIONS HUTCHENS AND CO WORKERS SUGGESTED DIRECT RELATIONSHIP BETWEEN LANGERHAN ’ S CELLS AND DEGREE OF KERATINISATION ( J.INVEST DERMATOL 56:325 1971) THE INCREASE IN LYMPHOCYTES AND LANGERHANS CELLS IN RESPONSE TO EXTERNAL ANTIGENIC CHALLENGE .( BOS AND BURKHARD(1980-81)) NEWCOMB ET AL ( JCP 1982 9:197) EXAMINED THE ATTACHED GINGIVA AS PLAQUE WAS ALLOWED TO ACCUMULATE. LANGERHANS CELLS APPEARED TO BECOME MORE DENDRITIC IN SHAPE AFTER 8 DAYS OF PLAQUE ACCUMULATION THAN AT DAY 0 .

32. AT 21 DAYS THE SAME MORPHOLOGIC APPEARANCE WAS NOTED AS AT 8 DAYS. AS DENTAL PLAQUE ACCUMULATED ADJACENT TO AND ON THE ATTACHED GINGIVA, THERE WAS A STATISTICALLY SIGNIFICANT INCREASE IN LCS IN THE STRATUM SPINOSUM REDUCTION IN LANGERHAN ’ S CELLS AFTER NON – SURGICAL PERIODONTAL THERAPHY WAS OBSERVED DEREKA.X.T, TOSIOS.K.I IN JPR 2004

33. INFLAMMATORY CELLS

34. INFLAMATORY CELLS ARE THE CELLS ACCOMPANIED BY OR TENDING TO CAUSE INFLAMMATION. SECTIONS OF EPITHELIUM TAKEN FROM CLINICALLY NORMAL AREAS, INFLAMATORY CELLS ARE SEEN IN NUCLEATED CELL LAYERS A FEW INFLAMMATORY CELLS ARE COMMON PLACE IN ORAL EPITHELIUM ,AND REGARDED AS A NORMAL COMPONENT OF NON- KERATINOCYTE POPULATION.

35. THESE ARE TRANSIENT AND DO NOT REPRODUCE THEMSELVES IN EPITHELIUM AS OTHER NON- KERATINOCYTES DO. LYMPHOCYTES ARE MORE COMMON ALTHOUGH PMN ’ S AND MAST CELLS ARE NOT UNCOMMON. LYMPHOCYTES ARE ASOCIATED WITH LANGERHAN ’ S CELLS, WHICH ARE ABLE TO ACTIVATE T-LYMPHOCYTES.

36. High-power view of junctional epithelium. Infiltrating leukocytes are a prominent feature

37. LYMPHOCYTES CELL OUT LINES ARE FAIRLY REGULAR WITH OCCASIONAL SURFACE PROJECTIONS. CYTOPLASM IS HOMOGENOUS WITH PLENTIFUL FREE RIBOSOMES AND MODEST MITOCHONDRIA BUT LITTLE RER, SER, AND FEW LYSOSOMES OR SECRETORY GRANULES HAVE SMALL ROUND NUCLEI AND CONDENSED CHROMATIN,CLUMPED AROUND PERIPHERY (@WHEELERS FUNCTIONAL HISTOLOGY PAGE 198). nucleus lysosomes mitochondria ribosomes

38. MERKEL CELLS

39. ONE AMONG THE NON-KERATINOCYTE CELL POPULATIONS, SPECIALIZED FORMS PART OF DIFFUSE NEURO- ENDOCRINE SYSTEM . (WINKELMANN.R.K) A CELL THAT OCCURS IN THE BASAL PART OF EPIDERMIS AND MUCOSA THEY WERE FIRST DESCRIBED BY MERKEL (1875) AS A SPECIALIZED EPITHELIAL CELL FOUND AT OR NEAR THE TIPS OF RETE RIDGES.

40. USUALLY ADJACENT TO A NERVE CELL, FUNCTION AS TOUCH RECEPTOR CELLS (PATRIZI AND MUNGER, 1966;MUNGER, 1975). MERKEL-LIKE CELLS IN MALASSEZ EPITHELIUM IN THE PERIODONTAL LIGAMENT OF CATS (@ Tadokoro1, T.,et al J Periodont Res 2002;)

41. IN MOUTH THEY ARE PREDOMINANTLY LOCATED IN GINGIVA,BUCCAL MUCOSA AND HARD PALATE. (FORTMANN.GT;WINKELMANN.R.K; TACHI BANA.T; NAVATI.),

42. ORIGIN : THESE CELLS ARISE FROM THE DIVISION OF AN EPITHELIAL CELL (KERATINOCYTES).

43. STRUCTURE ORAL MERKEL CELLS ARE SHOWN TO HAVE A DIVERSE MORPHOLOGY, WITH EITHER A DENDRITIC OR A ROUNDISH CELL SHAPE

44. ULTRA STRUCTURE : CONTAIN FEW TONO FILAMENTS AND DESMOSOMES LINKING TO ADJACENT CELLS. SO DOES NOT ALWAYS RESEMBLE OTHER CLEAR CELLS.

45. FUNCTION & PROPERTIES OF MERKEL CELLS???

46. THEY ARE LOCATED AT THE BASE OF RETE-PEGS,NEAR TO NERVE AXONS MERKEL CELL-NEURITE COMPLEX. FUNCTION AS SLOW ADAPTING MECHANO-RECEPTOR WITH A RELATIVELY SMALL RECEPTOR FIELD(TYPE SA-1). MERKEL CELL NEURITE COMPLEX

47. MERKEL CELLS AND THEIR ASSOCIATED NERVE ENDINGS EXPRESS RECEPTORS FOR “EPIDERMAL GROWTH FACTOR” , BUT THEY DO NOT MAKE. THE EGF IS EXPRESSED BY ADJACENT KERATINOCYTES ,SUGGESTING THAT THEY CONTROL DIFFERENTIATION OF MERKEL CELLS VIA A PARACRINE- EPIDERMAL GROWTH FACTOR EFFECT.

48. SURVIVAL OF MATURE MERKEL CELL ---- NEUTROTROPHIC FACTORS SECRETED FROM THE ASSOCIATED NERVE ENDINGS. SEVERENCE OF A β FIBERS LEADS TO ATROPHY OF MERKEL CELL. THERE IS ALSO EVIDENCE OF RECIPROCAL STIMULATION,MERKEL CELLS MAY ACT AS TARGET CELLS SECRETING SUBTANCES THAT ATTRACT AFFERENT SENSORY AXONS TOWARDS THEIR LOCATION IN EPITHELIUM. (CHENG CHEW S.B,LEUNG )

49. GRANULES 50-140nm IN DIAMETER SURROUNDED BY LIMITING MEMBRAN (GARANT ETAL) MOST GRANULES ARE CONCENTRATED BETWEEN THE GOLGI COMPLEXAND THE PLASMA MEMBRANE THAT ABUTS THE ADJACENT NERVE TERMINAL. ORIGINATE FROM THE GOLGI APPARATUS , SECRETORY IN NATURE. NEUROPEPTIDES (HISTIDINE,LEUCINE, VASOACTIVE INTESTINAL POLYPEPTIDE) LOCALISED IN GRANULES BY IMMUNOCYTOCHEMISTRY .

50. RELEASE OF NEUROPEPTIDE IN THE IMMEDIATE VICINITY OF NERVE ENDINGS KEEP THE RECEPTOR IN THE HIGHTENED STATE OF RESPONSIVENESS. DEPLETION OF MERKEL CELL GRANULES LEADS TO DECREASED RESPONSIVENESS OF NEURITE. T HE MERKEL CELL PLASMA MEMBRANE FACING THE NERVE ENDING APPEARS TO HAVE A SYNAPTIC SPECIALISATION.

51. THE MERKEL CELL NEURITE CONTAINS NUMEROUS MITOCHONDRIA INDICATING THAT IT HAS HIGH METABOLIC ACTIVITY .

52. HAVE MANY SPINY CYTOPLASMIC PROCESSES THAT PROJECT INTO ADJACENT INTER CELLULAR SPACES AND INDENT THE CYTOPLASM OF A ADJACENT KERATINOCYTE (GARANT) SPINES CONTAIN CYTOPLASMIC FILAMENTS THAT INTERCONNECT WITH LARGER FILAMENT NETWORK IN CYTOPLASM.

53. THE FUNCTION UNCLEAR HOWEVER THEY APPEAR SUITED FOR DETECTING AND AMPLIFYING THE MOVEMENT OF ADJACENT EPITHELIUM,POSSIBLY BY DEFORMING STRETCH ACTIVATED CATIONIC CHANNELS IT HAS BEEN SPECULATED THAT MECHANICAL DISPLACEMENT OF EPITHELIUM,AMPLIFIED BY SPINES OF MERKEL CELLS,LEADS TO DISCHARGE OF NEURO TRANSMITTOR GRANULES AND ACTIVATIONOF ADJACENT NERVE ENDING. .(TAZAKI.M, SUZUKI.T).

54. I N HUMANS AND PRIMATES THESE CELLS ARE HIGHLY CONCENTRATED IN SKIN OF FINGER TIPS. ( Patrizi and Munger , 1966;Munger, 1975). NEURO-PHYSIOLOGIC STUDIES OF FINGER TIP MERKEL CELL NERVE COMPLEX HAVE LED TO THE CONCLUSION THAT THEY PROVIDE TACTILE INFORMATION FOR THE SHAPE AND TEXTURE PERCEPTION. ( BLAKE D.T,JOHNSON.K,HSIAO S.S..)

55. IT IS PROPOSED THAT MERKEL-CELL NERVE COMPLEXES OF ORAL MUCOSA PLAY A SIMILAR TACTILE SENSORY FUNCTION I N RECOGNITION OF PARTICLE SIZE AND TEXTURE DURING MASTICATION. BECAUSE OF THEIR RELATIVELY SMALL RECEPTIVE FIELDS THE SA- 1NERVE ENDINGS ALSO PROVIDE FOR TWO POINT DICRIMINATION.

56. STAINING: DIFFICULT TO DISTINGUISH FROM KERATINOCYTES BY ROUTINE LIGHT MICROSCOPY . BUT CAN READILY BE IDENTIFIED BY ELECTRON MICROSCOPY. AS THEY CONTAIN DENSE-CORE GRANULES , ARE ASSOCIATED WITH NERVES IN THE BASAL OR SUPRABASAL CELL LAYERS OF ORAL EPITHELIA (FORTMAN AND WINKELMAN, 1977) . (K.H. NESS, T.H. MORTON AND B.A. DALE J DENT RES 1987; 66; 1154)

57. MERKEL CELLS HAVE ALSO BEEN IDENTIFIED BY FLUORESCENCE AFTER INJECTION OF ANIMALS WITH THE DYE QUINACRINE ( NURSE ET AL., 1983 ), WHICH IS SPECIFICALLY TAKEN UP INTO NEUROENDOCRINE GRANULES, BY ANTISERUM TO NEURON-SPECIFIC ENOLASE (GU ET AL., 1981.) IN TISSSUE SECTIONS THEY ARE IDENTIFIED BY STAINING OF ANTIBODIES TO KERATINS-18, 19, 20. IDENTIFICATION OF MERKEL CELLS IN ORAL EPITHELIUM USING ANTIKERATIN AND ANTINEUROENDOCRINE MONOCLONAL ANTIBODIES (K.H. NESS, T.H. MORTON AND B.A. DALE J DENT RES 1987; 66; 1154) CHROMOGRANIN A - A MATRIX COMPONENT OF MERKEL CELL GRANULES

58. MELANOCYTES

59. PIGMENT PRODUCING DENDRITIC CELLS IN THE BASAL LAYER OF ORAL EPITHELIUM AND EPIDERMIS. BY BECKER IN 1927, THEY WERE ISOLATED FROM SAMPLES OF GINGIVAL TISSUE BY LAIDLOW AND CAHN.

60. “ MELANIN ” ,IT IS A NON-HEMOGLOBIN DERIVED BROWN PIGMENT AND IS RESPONSIBLE FOR NORMAL PIGMENTATION OF SKIN,GINGIVA AND ORAL MUCOSA. GINGIVA, BUCCAL MUCOSA,HARDPALATE AND TONGUE. MELANIN FUNCTIONS TO ABSORB U.V LIGHT AND SCAVENGING SOME CYTOTOXIC COMPOUNDS. MELANOSOMES

61. ORIGIN : (@ORBANS ORAL HISTOLOGY) DURING INTRA-UTERINE LIFE, PRE-CURSORS OF MELANOCYTES THAT IS MELANOBLASTS, MIGRATE FROM “ NEURAL CREST” TO EPITHELIUM /EPIDERMIS AND HAIR FOLLICLES, BECOME DIFFERENTIAITED INTO DENDRITIC CELLS. HEAD AND NECK IS THE FIRST PART OF THE BODY WHERE MELANOCYTES APPEAR AROUND 11WEEKS OF GESTATION PERIOD. IN EPITHELIUM THEY DIVIDE AND MAINTAIN THEMSELVES AS A SELF REPRODUCING POPULATION .

62. MELANOCYTES ARE LONG BRANCHING PROCESS THAT EXTEND BETWEEN KERATINOCYTES OFTEN PASSING THROUGH SEVERAL LAYERS OF CELLS. THE WIDTH OF THE PROJECTIONS VARIED RANGING FROM 0.23 TO 3.40 MICRONS. THERE WAS A REVERSE RELATIONSHIP BETWEENTHE NUMBER OF PREMELANOSOMES AND MEIANOSOMES, AND THE APPROXIMATE SURFACEAREA OF THE INTERSECTED CYTOPLASMIC PROJECTIONS STRUCTURE

63. ULTRA STRUCTURE AND FUNCTION: ROUND NUCLEUS AND ASMALL AMOUNT OF CLEAR CYTOPLASM WITH MELANOSOMES AND PRE MELANOSOMES. SLENDER DENDRITES EXTENDING BETWEEN KERATINOCYTES.

64. TWO TYPES OF STRUCTURALLY DIFFERENT MELANOCYTES COULD BE DISTINGUISHED: 1) INACTIVE 2) ACTIVE CELLS.

65. THE INACTIVE MELANOCYTE : HAD A NUCLEUS VARYING FROM OVOID, ROUND TO SLIGHTLY INDENTED OUTLINES. THROUGHOUT THE CYTOPLASM, DELICATE FILAMENTS WERE PRESENT, WHICH WERE LESS ELECTRON DENSE THAN THOSEOF KERATINOCYTES. THE NORMAL SET OF ORGANELLES APPEARED POORLY DEVELOPED. WITH A FEW EXCEPTIONS, THERE WERE NO MELANOSOMES. PREMELANOSOME ARE REPRESENTED AS MEMBRANE BOUND ORGANELLI(0.2 MICRONS)

66. ACTIVE MELANOCYTES : DIFFERENTLY SHAPED NUCLEI . PROMINENT GOLGI APPARATUS. PREMELANOSOMES IN ALL DEVELOPMENTAL STAGES AND FULLY MELANIZED MEIANOSOMES ( N=40 TO 130). ABOUT ONE QUARTERTO ONE THIRD OF THESE WERE FULLY MELANIZED,EXTREMELY ELECTRON DENSE MEIANOSOMES. ( HUBERT SCHHOEDER J.periodom . Res. 4: 1-18. 1969)

67. STRUCTURE AND DEVELOPMENTAL STAGES OF PREMELANOSOMES: MEMBRANE BOUND ORGANELLES OF OVOID SHAPE./ROD/RACHET SHAPED MAINLY 2 TYPES OF STRUCTURALLY DIFFERENT PREMELANOSOMES,

68. ONE TYPE: EXHIBITED AN INNER STRUCTURE OF LOOSE SPIRAL COILS RUNNING PARALLEL OR SLIGHTLY CURVED TO THE LONG AXIS OF THE ORGANELLE . BECAUSE OF IRREGULARITIES IN ITS COURSE AND APPEARANCE, THE PERIODICITY OF THE SPIRAL COILS COULD NOT ACCURATELY BY MEASURED

69. THE INNER STRUCTURE OF THE SECOND TYPE OF PREMELANOSOME APPEARED AS A SINGLE OR COMPOSITE STRIATED BAR(S) RUNNING PARALLEL TO THE LONG AXIS OF THE ORGANELIE WHICH OTHERWISE WAS GRANULAR OR APPARENTLY ELECTRON LUCENT. FREQUENTLY, THE STRIATED BAR(S) ALMOST FILLED THE MEMBRANE BOUND ORGANELLE.

70. MELANIN IS SYNTHESISED WITHIN MELANOSOMES. THEY CONTAIN TYROSINASE WHICH HYDROXYLATES TYROSINE TO DOPA WHICH IN TURN IS PROGRESSIVELY CONVERTED TO MELANIN. THE MALANOSOMES ARE INOCULATED INTO CYTOPLASM OF ADJACENT KERATINOCYTES BY THE DENDRITIC PROCESS TYROSINE DOPA MELANIN TYROSINASE

71. MELANOSOMES ARE IDENTIFIED UNDER LIGHT MICROSCOPE ,.IN HEAVLYPIGMENTED TISSUE WHICH STAINS WITH H&E,THEY ARE REFERRED AS “ MELANIN GRANULES ” . LIGHT AND DARKLY PIGMENTED INDIVIDUALS HAVE SAME NUMBER OF MELANOCYTES BUT DIFFERENCE RESULT FROM RELATIVE ACTIVITY OF MELANOCYTES. IN HEAVILY PIGMENTED INDIVIDUALS MELANOCYTES ARE SEEN IN CONNECTIVE TISSUE,THEY ARE PROBABLY MACROPHAGES THAT HAVE TAKEN UP BY MELANOSOMES,THEY ARE CALLED AS “ MELANOPHAGES ” .

72. LABELLING OF MELANOCYTES : 3,4 DI HYDROXY PHENYLALANINE A SUBSTRATE FOR TYROSINE . ARGENTIFFINIC MELANIN LABELLING TECHNIQUE-MASSAN FONTANAN STAIN IS USED,INACTIVE MELANOCYTES DOES NOT STAIN WITH THIS METHOD. IMMUNO-HISTOCHEMISTRY: S100 ANTIGEN IS THE MOST COMMON MARKER.IT APPEARS TO BE STRONGER IN MELANOCYTES LACKING PIGMENT HMB -45 A MONOCLONAL ANTIBODY DIRECTED AGAINST A MELANOSOMAL GLYCOPROTEIN.

73. CELL TYPE LEVEL IN EPITHELIUM SPECIFIC STAINING REACTIONS ULTRA STRUCTURAL FEATURES FUNCTION LANGERHAN’S CELLS SUPRA BASAL CD1A,CELL SURFACE ANTIGEN DENDRITIC,NO DESMOSOMES OR TONOFILAMENTS, CHARACTERISTIC LH GRANULES ANTIGE TRAPPING AND PROCESSING MERKEL CELLS BASAL PAS STAINING NON-DENDRITIC,SPARSE DESMOSOMES,TONOFILAMENTS,CHARACTERISTIC ELECTRON DENSE VESICLES AND ASSOCIATED NERVE AXON TACTILE SENSORY CELL. MELANOCYTES BASAL DOPA OXIDASE-TYROSINASE,SILVER STAINS DENDRITIC,NO DESMOSOMES OR TONOFILAMENTS;PRE-MELANOSOMES AND MELANOSOMES PRESENT SYNTHESIS OF MELANIN AND TRANSFER TO SURROUNDING KERATINOCYTES LYMPHOCYTES VARIABLE CD3-TCELLS, CD20-BCELLS LARGE CIRCULAR NUCLEUS,SCANT CYTOPLASM WITH FEW ORGANELLES,NO DESMOSOMES OR TONOFILMENTS ASSOCIATED WITH INFLAMMATORY RESPONSE

74. SUMMARY NON-KERATINOCYTES THOUGH THEY DO NOT PARTICIPATE IN THE MATURATION OF EPITHELIUM,THEY ARE THE PROTECTIVE CELLS AT THE BODY SURFACES (SKIN/MUCOUS MEMBRANE), LANGERHAN’S CELLS STIMULATE LYMPHOCYTES. MERKEL CELLS ARE TACTILE RECEPTORS. MELANOCYTES PIGMENT PRODUCING CELLS ,PROTECT THE BODY FROM UV RAYS(SKIN),

75. CONCLUSION: CLEARLY THE ASSOCIATION BETWEEN KERATINOCYTE AND NON- KERATINOCYTES IN SKIN AND ORAL MUCOSA REPRESENT A SUBTLE AND FINELY BALANCED INTER-RELATIONSHIP IN WHICH CYTOKINES ARE CONTROLLING FACTORS. KERATINOCYTES PRODUCE CYTOKINES THAT MODULATE THE FUNCTION OF LANGERHAN CELLS.INTURN, LANGERHAN CELLS PRODUCE CYTOKINES SUCH AS IL-1 WHICH CAN ACTIVATE T-LYMPHOCYTES, SO THAT THEY ARE CAPABLE OF RESPONDING TO ANTIGENIC CHALLENGE.

76. IL-1 ALSO INCREASES NUMBER OF RECEPTORS TO MELANOCYTE STIMULATING HARMONE IN MELANOCYTES AND SO CAN EFFECT PIGMENTATION. THE INFLUENCE OF KERATINOCYTES EXTEND TO ADJACENT CONNECTIVE TISSUE, WHERE CYTOKINES PRODUCED IN EPITHELIUM CAN INFLUENCE FIBROBLAST GROWTH AND FORMATION OF FIBRILS AND MATRIX PROTEIN .

77. BIBILOGRAPHY CARRANZA 10 TH EDITION LINDHAE 5 TH EDITION ROSE AND MEILEY TENCATES-ORAL HISTOLOGY GARANT’S ORAL CELLS AND TISSUES ORAL MICROBIOLOGY AND IMMUNOLOGY PHYSIOLOGY-ROBINSONS, WHEELERS HISTOLOGY. JPR 2004,2002,1978,1969 PERIO 2000: 2004 JDR 1987

78. “DREAM” IS THE ENTRANCE “HARDWORK” IS THE VEHICLE “PERSEVERANCE “ IS THE ROUTE. WHEN WE HAVE ALL THESE WE WILL ACHIEVE OUR GOAL JUST LIKE THAT… THANK YOU