Transplantation
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The extreme demand for human organs or tissues for transplantation has driven the search for viable alternatives. Pigs are considered a possible source of tissue for a number of reasons including shared physiology, plentiful supply, short gestation, and, more recently, the generation of transgenic animals. Porcine islets show promise as a source of islets for the treatment of type 1 diabetes mellitus. ⋯ Xenogeneic islets are susceptible to complement-mediated lysis after the binding of preformed natural antibodies and cellular immunity involving both macrophages and CD4+ T cells. In addition, the potential for transmission of porcine endogenous retroviruses, porcine cytomegalovirus, and porcine lymphotropic herpesvirus type 1 are all concerns that must be addressed. Despite the challenges facing xenotransplantation, the extreme need for donor organs and tissues continues to drive progress toward overcoming the unique issues associated with transplantation between species.
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A major problem in the field of transplantation is the persistent shortage of donor organs and tissues for transplantation. This study was initiated to (1) chart the donor potential for organs and tissue in The Netherlands and (2) to identify factors influencing whether donation is discussed with next of kin. ⋯ In The Netherlands, when taking into account current refusal percentages, 320 to 360 organ donations and 5,800 tissue donations could be effectuated if organ donation is posed to all possible donors. For this, knowledge of medical criteria and contraindications for donation by the physicians and their willingness to discuss donation with next of kin must be improved.
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The incidence of pulmonary embolism (PE) in lung transplant recipients has not been well established. The purpose of this study was to describe the incidence of clinically unsuspected PE in a cohort of lung transplant recipients requiring mechanical ventilatory support. These patients underwent surgical lung biopsy (SLBx) for progressive deterioration in the absence of a specific diagnosis. ⋯ A high index of suspicion and reliance on ancillary diagnostic testing may be insufficient to establish the diagnosis of postoperative pulmonary emboli. PE is an underappreciated complication contributing to respiratory failure in the early postoperative period in lung transplant recipients, warranting identification of putative risk factors and consideration for prophylaxis.
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Clinical composite-tissue (hand) transplantation between genetically disparate individuals currently requires potent, nonspecific immunosuppressive agents that are neither completely successful in preventing acute episodes of rejection nor free from complications. The reliance on long-term immunosuppression has prompted this study to achieve donor-specific transplantation tolerance in adult recipients using a nontoxic, nonmyeloablative protocol. ⋯ Although efforts have been made to induce tolerance to composite tissue allografts in adult recipients, thus far, none have succeeded without toxic, myeloablative host preconditioning. Our demonstration that tolerance can be achieved with minimal preconditioning provides a rationale for application to large animals and humans and suggests that although composite tissue allografts may have a significant skin component (and are therefore felt to be highly antigenic), protocols used to induce tolerance to organ transplants may be equally applicable to composite-tissue allotransplantation.
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In patients with acute liver failure (ALF) of unknown cause, viral infections are believed to be involved. This study investigates the involvement of human herpesvirus-6 (HHV-6). ⋯ HHV-6 was found in most explanted livers of patients with ALF of unknown cause. HHV-6 antigenemia was associated with HHV-6 antigens in the liver. Only a few control patients displayed HHV-6 in the liver. These observations indicate that HHV-6 may be one of the causes of ALF.