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Transplantation

Transplantation (graft) . Transplantation :Transfer of tissues(organ) from individual to individual . Classification. According to implanting site : *Orthotopic Transplantation: transplanted organ in it's normal anatomical position (heart, lung, liver) *Heterotopic Transplantat

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Transplantation

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    1. Transplantation DONE BY: NOURA HEILF & SUMAIA RABABAH DR. NAWAF SHATANAWI

    2. Transplantation (graft) Transplantation :Transfer of tissues(organ) from individual to individual

    3. Classification According to implanting site : *Orthotopic Transplantation: transplanted organ in it’s normal anatomical position (heart, lung, liver) *Heterotopic Transplantation: transplanted organ not in it’s normal anatomical position(kidney, pancreas) , the diseased organ is not usually removed

    4. According to the source of tissue : *Autotransplant : from individual to it self (skin graft) *Isograft transplantation: transplant between identical twins *Allograft : between genetically nonidentical member of same species ,( human to human) *Xenograft :between member of different species eg. Pig to human

    5. Indication Solid organ stop function. Criteria of transplantation: *the damage is irreversible *no alternative Tx *the dis must not recur *chance of rejection must be minimized

    6. Organ donors There are two potential sources of donor organs : Living donors : Living donation applies mainly to kidney transplantation , where the donor can maintain adequate renal function with only one kidney and donate the other to ablood relative or , less commonly , their partner. As with any operation , there are risks to the donor especially of post-operative events such as chest and wound infection ,DVT , and pulmonary embolism .

    7. Donation of a portion of the liver , either to a child or another adult , has been performed but with greater risk to the donor who is subjective to a major operation and may have borderline liver function from the remaining liver lobe . Live donation of a lung lobe has also been performed .

    8. Deseased donors Most organs for transplantation come from donors who have sustained a lethal brain stem injury following a head injury , intracranial haemorrhage or primary brain tumor , and who have been certified dead by “brain stem criteria” . The organs are removed from donor in the operating theater after isolating their vascular pedicles while the heart is still beating , when circulation ceases the organs undergo rapid cooling and perfusion with a preservation solution .

    9. Asystolic donation , in which the organs are removed from the donor after cardiac arrest , is also possible for kidney , and more recently liver donation . Up to 90 min of warm ischaemia between cessation of circulation and perfusion with cold preservation fluid can be tolerated by kidney, around 20 min can be tolerated by the liver.

    10. Exclusions to organ donation There are three main reasons why a potential donor may be unsuitable . 1- potential transmission of infection . The transplanted organ could carry with it viral infections such as hepatitis B and C and HIV , and any bacterial infection that was disseminated in the donor . 2- malignancy . Malignant disease in the donor can be transplanted into the recipient where it may become established in the immunosuppressed environment . E.g superficial non melanoma skin tumors is a contraindication to organ donation 3- impaired function of donor organ . E.g a heart with sever coronary artery disease is unsuitable , and a donor with polycystic kidneys is an unsuitable kidney donor , but may be a suitable heart donor .

    11. MHC (major histocompatibility complex) In chromosome 6 Human type called HLA 3 class: ? :in all nucleated cell. encoded by A,B and C loci. Presented peptide Ag from inside to the cytotoxic Tcell ( CD8) II :in B-cell, macrophage and dendritic cell (Ag presenting cell). encoded by DP,DR and DQ loci. Presented phagocytosed Ag from outside to T helper cell (CD4) III :encoded for other immune component ( complement system, cytokine)

    12. T- lymphocyte Lymphocyte with thymus maturation Carries specific cell receptors and marker (CD4 ,CD8) They can recognized foreign antigen presented by APC(antigen presenting cell) Once presented with an antigen they will produce IL,and proliferate (cloning)

    13. We have two problem with transplantation 1- Immune rejection 2- Availability of the transplanted tissue

    14. Tolerance and Rejection Tolerance: no immune responses following exposure to an Ag Rejection: damage done by immunity system to transplanted organ

    15. Types of rejection Hyper acute: *Within hours of transplantation *Caused by: preformed Ab binding to ABO or HLA- I Ag (During pregnancy, blood transfusion, previous transplant) * it is type II hypersensitivity reaction (Ab mediated) * graft destroyed by vascular thrombosis * prevented by ABO and HLA cross matching

    16. Acute : *5-14 days *type VI hypersensitivity reaction (cell mediated) (delay hypersensitivity) *Caused by: HLA incompatibility *prevented by HLA cross matching Clinacally , acute rejection is characterized by a pyrexia , enlargement and tenderness over the transplanted organ , and biochemical dysfunction ( arise in creatinine in a renal transplant , elevated liver enzyme in a liver transplant )

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