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Donor Source (donor + source)
Selected AbstractsClinical islet transplant: current and future directions towards toleranceIMMUNOLOGICAL REVIEWS, Issue 1 2003A. M. James Shapiro Summary:, The ultimate goal of islet transplantation is to completely correct the diabetic state from an unlimited donor source, without the need for chronic immunosuppressive drug therapy. Although islet transplantation provides an opportunity to develop innovative strategies for tolerance in the clinic, both alloimmune and autoimmune barriers must be controlled, if stable graft function is to be maintained long-term. After islet extraction from the pancreas, the cellular graft may be stored in tissue culture or cryopreserved for banking, providing an opportunity not only to optimally condition the recipient but also to allow in vitro immunologic manipulation of the graft before transplantation, unlike solid organ grafts. As such, islets may be considered a ,special case.' Remarkable progress has occurred in the last three years, with dramatic improvements in outcomes after clinical islet transplantation. The introduction of a steroid-free, sirolimus-based, anti-rejection protocol and islets prepared from two (or rarely three) donors led to high rates of insulin independence. The ,Edmonton Protocol' has been successfully replicated by other centers in an international multicenter trial. A number of key refinements in pancreas transportation, processing, purification on non-ficoll-based media, storage of islets in culture for two days and newer immunological conditioning and induction therapies have led to continued advancement through extensive collaboration between key centers. This review outlines the historical development of islet transplantation over the past 30 years, provides an update on current clinical outcomes, and summarizes a series of unique opportunities for development and early testing of tolerance protocols in patients. [source] Absence of transmission of potentially xenotic viruses in a prospective pig to primate islet xenotransplantation study,JOURNAL OF MEDICAL VIROLOGY, Issue 11 2008Olga Garkavenko Abstract Shortage of human donor organs for transplantation has prompted usage of animals as an alternative donor source. Pigs are the most acceptable candidate animals but issues of xenozoonoses remain. Despite careful monitoring of designated pathogen free pigs there is still a risk that their tissues may carry infectious agents. Thus xenotransplantation requires extensive pre-clinical study on safety of the graft especially for those viruses that are either potentially oncogenic and/or immunosuppressive, or can establish persistent infection. A prospective pig-to-primate islet xenotransplantation study was performed which includes monitoring for potentially xenotic viruses namely porcine endogenous retrovirus (PERV), porcine cytomegalovirus (PCMV), porcine lymphotropic herpesvirus (PLHV), and porcine circovirus (PCV) using both molecular diagnostic,PCR and RT-PCR and serology methods. There was no evidence of pig virus transmission into primate recipients. This preclinical study underlines the information concerning viral safety of islet cell xenograft in pig-to-primate xenotransplantation. J. Med. Virol. 80:2046,2052, 2008. © 2008 Wiley-Liss, Inc. [source] Invasion genetics of the Eurasian round goby in North America: tracing sources and spread patternsMOLECULAR ECOLOGY, Issue 1 2009JOSHUA E. BROWN Abstract The Eurasian round goby Neogobius melanostomus (Apollonia melanostoma) invaded the North American Great Lakes in 1990 through ballast water, spread rapidly, and now is widely distributed and moving through adjacent tributaries. We analyse its genetic diversity and divergence patterns among 25 North American (N = 744) and 22 Eurasian (N = 414) locations using mitochondrial DNA cytochrome b gene sequences and seven nuclear microsatellite loci in order to: (i) identify the invasion's founding source(s), (ii) test for founder effects, (iii) evaluate whether the invasive range is genetically heterogeneous, and (iv) determine whether fringe and central areas differ in genetic diversity. Tests include FST analogues, neighbour-joining trees, haplotype networks, Bayesian assignment, Monmonier barrier analysis, and three-dimensional factorial correspondence analysis. We recovered 13 cytochrome b haplotypes and 232 microsatellite alleles in North America and compared these to variation we previously described across Eurasia. Results show: (i) the southern Dnieper River population was the primary Eurasian donor source for the round goby's invasion of North America, likely supplemented by some alleles from the Dniester and Southern Bug rivers, (ii) the overall invasion has high genetic diversity and experienced no founder effect, (iii) there is significant genetic structuring across North America, and (iv) some expansion areas show reduced numbers of alleles, whereas others appear to reflect secondary colonization. Sampling sites in Lake Huron's Saginaw Bay and Lake Ontario significantly differ from all others, having unique alleles that apparently originated from separate introductions. Substantial genetic variation, multiple founding sources, large number of propagules, and population structure thus likely aided the goby's ecological success. [source] Applications of mulch biowalls,three case studiesREMEDIATION, Issue 1 2009Kevin A. Morris Mulch biowalls are proving to be an effective means of generating reducing conditions for the in situ anaerobic reduction of contaminants in groundwater that are amenable to the reduction process. Mulch is an inexpensive and readily available substrate that provides a long-lasting carbon and electron donor source for the stimulation of the anaerobic reduction process in groundwater. Examples of contaminants that are amenable to the biotic anaerobic reduction process include: chlorinated alkenes and alkanes, explosives, perchlorate, some metals, and petroleum hydrocarbons. The microbial degradation of cellulose fibers (mulch) is arguably the oldest reduction process known and is evident anywhere that plant material, soil, and water are present together. This article presents three case studies discussing three different uses of mulch biowalls to stimulate the anaerobic bioremediation of contaminants in shallow soils and groundwater. © 2009 Wiley Periodicals, Inc. [source] Focal C4d+ in Renal Allografts Is Associated with the Presence of Donor-Specific Antibodies and Decreased Allograft SurvivalAMERICAN JOURNAL OF TRANSPLANTATION, Issue 4 2009R. L. Kedainis Diffuse peritubular capillary C4d deposition in renal allograft biopsies is associated with donor-specific antibodies (DSA) and graft failure. The significance of focal C4d+ is unclear. We reviewed 368 biopsies from 301 patients performed for renal dysfunction or proteinuria over 5 years. Diffuse C4d+, focal C4d+ and C4d- detected by immunofluorescence occurred in 9.5%, 20.9% and 69.4% of biopsies, respectively. Patients were similar in gender, age, cause of renal disease, donor source, HLA mismatch, serum creatinine at baseline and interval from transplantation to biopsy. Diffuse and focal C4d+ were associated with acute cellular rejection (p < 0.001). Transplant glomerulopathy was associated with diffuse C4d+. DSA at the time of biopsy, were positive in 79.3% of diffusely C4d+ patients, 68.8% of those with focal C4d+ (p = 0.27) and 9.9% of patients with C4d- (p < 0.001, compared to either the focal or diffuse groups, respectively). Allograft survival at 40 months was lower in diffuse C4d+ compared to the C4d- group (p = 0.014), but not when compared to the focal C4d+ group. There was a clear trend toward worse graft survival in patients with focal C4d+ in this time interval, but focal C4d+ compared to both diffuse C4d+ and C4d-groups was not statistically significant (p = 0.08). [source] Kidneys from patients with small renal tumours: a novel source of kidneys for transplantationBJU INTERNATIONAL, Issue 2 2008David L. Nicol OBJECTIVE To report the use of a novel donor source as a further option to increase the number of patients who might be able to receive a renal transplant. PATIENTS AND METHODS Between May 1996 and July 2007, 43 kidneys were transplanted using kidneys obtained from patients with small (<3 cm diameter) incidentally detected tumours. After bench surgery to excise the tumour, they were all successfully transplanted into patients who were elderly or had significant comorbidities. RESULTS Apart from four patients who died from unrelated illnesses, all grafts continued to function with a median and mean follow-up of 25 and 32 months. The follow-up, which included 3-monthly renal ultrasonography and chest X-rays, showed only one case of tumour recurrence, which occurred 9 years after transplantation; the patient remains stable under observation after 18 months. CONCLUSIONS From our experience we consider that where nephrectomy is used for small, localized, incidentally detected renal tumours, the kidney should be considered for transplantation into carefully selected patients. Such patients with numerous medical comorbidities might benefit from renal transplantation, but not survive the waiting period if they are dependent on a deceased donor graft. Paradoxically the use of these marginal kidneys has the potential to increase the quality and length of life of these patients, despite the apparent contradiction of an intuitive principle of organ transplantation and immunosuppression. [source] Risk factors for rising creatinine in renal allografts with 1 and 3 yr survivalCLINICAL TRANSPLANTATION, Issue 6 2006Steven Paraskevas Abstract:, Background:, Determining factors associated with negative slope of inverse creatinine vs. time (1/Cr vs. t) may help prevent a decline in renal allograft function. Methods:, A total of 1389 adult recipients of primary renal transplants were divided into quartiles based on the slope of 1/Cr vs. t calculated from 6 and 12 months post transplant. A multivariate analysis of risk factors for being in the worst vs. best quartile employed these variables: donor source, HLA mismatch, recipient age, donor age, panel-reactive antibody (PRA), acute rejection (AR), 3-month cyclosporin A (CsA) level, 1-yr CsA level and acute tubular necrosis. Two separate analyses compared risk factors in patients with 1 and 3 yr survival, respectively. Results:, In recipients with ,1 yr graft survival, high PRA and AR were associated with negative slopes of 1/Cr vs. t. For those with ,3 yr graft survival, both AR and 3-month CsA level >150 ng/mL were significant risk factors, using both 6- and 12-month slopes. Stratification of AR showed 1 AR episode ,6 months and multiple AR episodes carried significant risk for negative slopes. Conclusion:, Optimization of allograft function invokes a conundrum between the needs to avoid both AR and high early CsA levels. We support a policy of carefully balancing these two risks. [source] | |||||||||||||