China
Africa
Explore chapters and articles related to this topic
Medical Biotechnology
Published in Firdos Alam Khan, Biotechnology Fundamentals, 2020
An allograft or allotransplantation is the transplantation of cells, tissues, or organs sourced from a genetically nonidentical member of the same species as the recipient. The transplant is called an allograft or allogeneic transplant, or a homograft. Most human tissue and organ transplants are allografts. In bone marrow transplantation, the term for a genetically identical graft is syngeneic, whereas the equivalent of an autograft is termed autologous transplantation. When a host mounts an immune response against an allograft or xenograft, the process is termed rejection. For any number of reasons, before death, a person may decide to donate tissue from his or her body for transplant to another who is in need. Additionally, consent for donation may also be given by the donor’s family if the donor did not specify his or her wishes before death. After consent is obtained, potential donors are thoroughly screened for risk factors and medical conditions that would rule out donation. This screening includes interviews with family members, evaluation of medical and hospital records, and a physical assessment of the donor. Recovery of the tissue is performed with respect for the donor, using surgical techniques.
Medical biotechnology
Published in Firdos Alam Khan, Biotechnology Fundamentals, 2018
plantation of cells, tissues, or organs, sourced from a genetically non-identical member of the same species as the recipient. The transplant is called an allograft or allogeneic transplant, or a homograft. Most human tissue and organ transplants are allografts. In bone marrow transplantation, the term for a genetically identical graft is syngeneic, whereas the equivalent of an autograft is termed autologous transplantation. When a host mounts an immune response against an allograft or xenograft, the process is termed rejection. For any number of reasons, before death, a person may decide to donate tissue from his or her body for the purpose of transplant to another who is in need. Additionally, consent for donation may also be given by the donor’s family if the donor did not specify his or her wishes before death. After consent is obtained, potential donors are thoroughly screened for risk factors and medical conditions that would rule out donation. This screening includes interviews with family members, evaluation of medical and hospital records, and a physical assessment of the donor. Recovery of the tissue is performed with respect for the donor, using surgical techniques.
Ligament Reconstruction with Reference to the Anterior Cruciate Ligament of the Knee
Published in Verna Wright, Eric L. Radin, Mechanics of Human Joints, 2020
Natural tissue substitutes divide in turn into homograft, allograft, and xenograft substitutes. The homograft, or autogenous tissue, employed thus far includes the iliotibial band, semitendinosus and gracilis tendons, patellar ligament, and meniscus. Allografts are tissues harvested from cadavers, thus allowing the facility of transplanting ACL or PCL complete with attachments and bone blocks at either end, which has apparent merits. Allografts also include sections of the patellar ligament with bone blocks attached at both ends from the tibia and patella, iliotibial band, quadriceps tendons with bone blocks at one end, semitendinosus and gracilis tendons, and so on.
Anterior cruciate ligament (ACL) reconstruction– A numerical case study
Published in Cogent Engineering, 2022
Bharath K Bhat, Raviraja Adhikari, Kiran Kumar V Acharya
ACL reconstruction is surgical procedure in which the torn ACL is replaced by a graft. If the graft is taken from another person it is known of allograft. If it is taken from the same person it is known as autograft. If it is taken from another person it is known as allograft. Van Ek et al. (Charles Brown, 2014) define anatomic ACL reconstruction as the process of restoring ACL to its native site and orientation. There are three conditions for anatomic ACL reconstruction. First, the graft should replicate the size, shape and location of native ACL. Secondly, it should replicate the two functional bundles of native ACL. The tertiary condition is it should replicate the tensional pattern of native ACL. Finally, it should be individualized for every person as a every person has a different anatomical configuration when compared with another person. In Anteromedial Portal (AMP) technique an anteromedial portal is drilled in the femur. But, in the Traditional Transtibial (TT) technique this feature is absent. Knee joint which is considered for this study includes bones such as Tibia, Femur, and Fibula; stabilising ligaments like anterior cruciate ligament (ACL), articular cartilages, posterior cruciate ligament (PCL), medial collateral ligament (MCL), lateral collateral ligament (LCL); Femoral and Tibial cartilages, Menisci. The comparison between Traditional Transtibial and Anteromedial Portal techniques is shown in Figure 1 (a,b).
Effects of exercise training on immunological factors in kidney transplant recipients; a randomized controlled trial
Published in Research in Sports Medicine, 2022
Nazi Hemmati, Sohrab Kazemi, Narges Jamshidian-Tehrani, Jamshid Roozbeh, Maryam Koushkie Jahromi, Mohsen Salesi, Meghdad Abdollahpour-Alitappeh, Mohammad Hossein Karimi
Allograft rejection stems from coordinated activation of alloreactive T cells and antigen-presenting cells (APCs). In addition, a wide variety of cell mediators and cytokines are involved in this process. Secretion of different cytokines, including interleukin (IL)-2, IL-4, IL-5, IL-7, IL-10, IL-15, tumour necrosis factor-α (TNF-α), and interferon-γ (IFNγ) released from T cells, leads to recruitment of immunocompetent donor-specific CD4+ T cells, CD8+ cytotoxic T cells and B cells, as well as non-specific inflammatory cells, which constitute the majority of cells infiltrating an allograft (Chinen & Buckley, 2010; Karczewski et al., 2008). There is accumulating evidence showing the pivotal role of MHC class II in the activation of alloreactive CD4 + T against the transplanted organ (Ayala Garcia et al., 2012). Moreover, various studies have demonstrated the role of different CD4+ subsets in the allograft rejection. Of note, T helper type 1 (Th1), Th2, and Th17 cells exhibit an active participation in both acute and chronic allograft rejection.
Repair of rabbit radial bone defects using bone morphogenetic protein-2 combined with 3D porous silk fibroin/β-tricalcium phosphate hybrid scaffolds
Published in Journal of Biomaterials Science, Polymer Edition, 2018
Jaeyong Song, Junhyung Kim, Heung-Myung Woo, Byungil Yoon, Hyunjung Park, Chanhum Park, Byung-Jae Kang
Bones are capable of regenerative growth and remodelling, but these processes are often impaired in clinical situations with loss of bone due to disease, trauma, or tumour resection. More than 800,000 bone grafts are estimated to be performed globally every year [1]. Autograft is the standard bone repair method for the treatment of bone nonunion and defects. However, there are some drawbacks associated with autografts, such as limited abundance in supply, nerve damage, persistent pain, and new fractures. Allografts have been successfully used in orthopaedic surgery owing to their excellent bone conduction and abundant supply. However, allografts have potential risks of infection, disease transmission and immune response. On the other hand, allografts are inferior in promoting bone regeneration compared to autografts. This is because processing, sterilization, and preservation are required prior to their use [2–5]. Tissue engineering can therefore provide a promising approach to bone regeneration [6] The ideal bone graft material should show osteo-induction, osteo-conduction and mechanical strength, as well as provide empty space for vascularization and tissue infiltration, and be able to act as a carrier for the relevant therapeutic elements [7,8]. A new approach to treat bone defects involves the use of osteo-conductive and osteo-inductive biocompatible materials containing bioactive modules to promote cell migration and cell transplantation [9–11].