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The purpose of this study was to determine if muscle strength influences the hyperemic response to dynamic exercise. Men with low (n=8) and high (n=9) maximal forearm strength performed dynamic handgrip exercise as the same absolute workload increased in a ramp function (0.5kg·min-1). Forearm blood flow (FBF) was measured instantaneously by ultrasound Doppler and blood pressure was measured by auscultation. The pressor response to exercise was greater (P<0.05) for low strength men at workloads >1.5 kg allowing volumetric FBF (ml·min-1) and vascular conductance to increase in proportion to absolute workload similar to high strength men. When FBF was expressed relative to forearm volume (ml·min-1·100ml-1) the hyperemic response to exercise (slope of relative FBF vs. workload) was greater in low strength men (3.2±1.5 vs. 1.7±0.4ml·min-1·100ml-1·kg-1, P<0.05) as was relative FBF at workloads >1.5kg. However, when relative FBF was compared across relative work intensity, no difference was found between low and high strength groups. Together, these findings suggest men with low strength require a greater pressor response to match blood flow to exercise intensity as compared to high strength men. [ABSTRACT FROM AUTHOR]

Renal allograft arteriovenous (AV) fistula is a known complication of renal biopsies in patients experiencing renal allograft dysfunction. Treatment may include observation, surgery, or intraarterial embolization. We report a case of postbiopsy renal allograft AV fistula and pseudoaneurysm in which intraarterial embolization was technically impossible. Treatment included percapsular embolization of the pseudoaneurysm using intraoperative ultrasound guidance. The embolization coils served as a guide for subsequent percutaneous embolization of the AV fistula in the angiographic suite. Innovative embolization techniques may be necessary in order to preserve optimal renal function. [ABSTRACT FROM AUTHOR]

Some diseases that result from inborn errors of critical metabolic or synthetic processes mainly involving the liver do not cause structural liver damage. These disorders can be treated by the addition of liver tissue (auxiliary liver transplantation) rather than liver replacement. We report correction of the metabolic error in a 13-year-old girl with Crigler-Najjar syndrome type 1 by auxiliary (left lateral segment) transplantation. The first graft failed and was replaced successfully. The second graft shows features of chronic rejection, but at 2 years postoperatively bilirubin conjugating ability has not been impaired. Another graft may become necessary in due course. [ABSTRACT FROM AUTHOR]

We introduce a nonparametric survival prediction method for right-censored data. The method generates a survival curve prediction by constructing a (weighted) Kaplan-Meier estimator using the outcomes of the K most similar training observations. Each observation has an associated set of covariates, and a metric on the covariate space is used to measure similarity between observations. We apply our method to a kidney transplantation data set to generate patient-specific distributions of graft survival and to a simulated data set in which the proportional hazards assumption is explicitly violated. We compare the performance of our method with the standard Cox model and the random survival forests method., (Copyright © 2012 John Wiley & Sons, Ltd.)

Blocking the CD28/B7 and/or CD154/CD40 costimulatory pathways promotes long-term allograft survival in many transplant models where CD4(+) T cells are necessary for rejection. When CD8(+) T cells are sufficient to mediate rejection, these approaches fail, resulting in costimulation blockade-resistant rejection. To address this problem we examined the role of lymphotoxin-related molecules in CD8(+) T cell-mediated rejection of murine intestinal allografts. Targeting membrane lymphotoxin by means of a fusion protein, mAb, or genetic mutation inhibited rejection of intestinal allografts by CD8(+) T cells. This effect was associated with decreased monokine induced by IFN-gamma (Mig) and secondary lymphoid chemokine (SLC) gene expression within allografts and spleens respectively. Blocking membrane lymphotoxin did not inhibit rejection mediated by CD4(+) T cells. Combining disruption of membrane lymphotoxin and treatment with CTLA4-Ig inhibited rejection in wild-type mice. These data demonstrate that membrane lymphotoxin is an important regulatory molecule for CD8(+) T cells mediating rejection and suggest a strategy to avoid costimulation blockade-resistant rejection.

Background: Disruption of the CD40/CD154 pathway inhibits rejection in numerous models. The importance of this pathway on intestinal allograft rejection was examined in this study., Methods: Intestinal grafts from B6C3F1 mice transplanted into C57BL/6 recipients were assessed histologically for rejection., Results: The monoclonal antibody to CD154, MR1, failed to inhibit rejection in wild-type mice. Similarly, CD154-/- recipient mice rejected intestinal allografts. MR1 did inhibit early rejection in CD8-/- mice, but had no effect in CD4-/- recipients. All MR1-treated CD8-/- recipients eventually developed rejection. No benefit was observed when blockade of the CD40/CD154 pathway by MR1 was combined with blockade of the CD28/B7 pathway by mCTLA4Ig., Conclusions: These data suggest that CD4+ T cells mediating intestinal allograft rejection may be more dependent upon the CD40/CD154 pathway than CD8+ T cells. This finding highlights the importance of identifying agents that suppress CD8+ T cell-mediated rejection.

Although CD28 blockade results in long-term cardiac allograft survival in wildtype mice, CD28-deficient mice effectively reject heart allografts. This study compared the mechanisms of allogeneic responses in wildtype and CD28-deficient mice. Adoptive transfer of purified CD28-deficient T cells into transplanted nude mice resulted in graft rejection. However, this model demonstrated that the allogeneic T cell function was severely impaired when compared with wildtype T cells, despite similar survival kinetics. Cardiac allograft rejection depended on both CD4+ and CD8+ T cell subsets in CD28-deficient mice, whereas only CD4+ T cells were necessary in wildtype recipients. These results suggested that CD8+ T cells were more important in CD28-deficient than wildtype mice. In addition to the CD8+ T cell requirement, allograft rejection in CD28-deficient mice was dependent on a sustained presence of CD4+ T cells, whereas it only required the initial presence of CD4+ T cells in wildtype mice. Taken together, these data suggest that CD4+ T cells from CD28-deficient mice have impaired responses to alloantigen in vivo, thus requiring long-lasting cooperation with CD8+ T cell responses to facilitate graft rejection. These results may help to explain the failure to promote graft tolerance in some preclinical and clinical settings.

Plasmacytic infiltrates in renal allograft biopsies are uncommon and morphologically distinctive lesions that may represent variants of acute rejection. This study sought significant clinical and pathologic determinants that might have influenced development of these lesions and assessed their prognostic significance. Renal allograft biopsies (n = 19), from 19 patients, with tubulointerstitial inflammatory infiltrates containing abundant plasma cells, composing 32 +/- 8% of the infiltrating mononuclear cells, were classified using Banff '97 criteria. Clonality of the infiltrates was determined by immunoperoxidase staining for kappa and lambda light chains and polymerase chain reaction for immunoglobulin heavy-chain gene rearrangements, using V(H) gene framework 3 and JH consensus primers. In situ hybridization for Epstein-Barr virus encoded RNA (EBER) was performed in 17 cases. The clinical features, histology, and outcome of these cases were compared with kidney allograft biopsies (n = 17) matched for time posttransplantation and type of rejection by Banff '97 criteria, with few plasma cells (7 +/- 5%). Sixteen of 19 biopsies (84%) with plasmacytic infiltrates had EBER-negative (in 14 cases tested) polyclonal plasma cell infiltrates that were classifiable as acute rejection (types 1A [4], 1B [10], and 2A [2]). These biopsies were obtained between 10 and 112 months posttransplantation. Graft loss from acute and/or chronic rejection was 50% at 1 year and 63% at 3 years, and the median time to graft failure was 4.5 months after biopsy. There was no significant difference in overall survival or time to graft failure compared with the controls. Three of 19 biopsies (16%) had EBER-negative polyclonal plasmacytic hyperplasia, mixed monoclonal and polyclonal polymorphous B cell hyperplasia, and monoclonal plasmacytoma-like posttransplantation lymphoproliferative disease (PTLD) and were obtained at 17 months, 12 weeks, and 7 years after transplantation, respectively. Graft nephrectomies were performed at 1, 19, and 5 months after biopsy, respectively. Plasmacytic infiltrates in renal allografts comprise a spectrum of lesions from acute rejection to PTLD, with a generally poor prognosis for long-term graft survival.

STAT4(-/-) mice have impaired type 1 T cell differentiation, whereas STAT6(-/-) mice fail to generate type 2 responses. The role of type 1 and type 2 T cell differentiation in acute cardiac allograft rejection and in the induction of tolerance was examined in wild-type, STAT4(-/-), and STAT6(-/-) recipients. All recipients rejected the grafts promptly. Analysis of in situ cytokine gene expression in the allografts confirmed decreased levels of IFN-gamma in STAT4(-/-) recipients and undetectable levels of IL-4 and IL-5 in STAT6(-/-) mice. Blockade of the CD28/B7 costimulatory pathway prolonged cardiac graft survival for >100 days in 100% of wild-type and STAT4(-/-) mice. However, 14% of CTLA4-Ig-treated STAT6(-/-) mice rejected their grafts between 20 and 100 days. Moreover, of those animals followed past 100 days, 60% of the STAT6(-/-) mice rejected their grafts. Splenocytes harvested on day 145 posttransplant from CTLA4-Ig-treated rejecting STAT6(-/-) recipients were transfused into syngeneic SCID mice transplanted with donor or third party cardiac allografts. Both donor and third party grafts were rejected, indicating that the initial graft loss may be due to an immunological rejection. In contrast, when splenocytes from CTLA4-Ig-treated wild-type or nonrejecting STAT6(-/-) mice were transferred into SCID recipients, donor allografts were accepted, but third party hearts were rejected. Thus, long-term prolongation of cardiac allograft survival by CTLA4-Ig is STAT4-independent but, at least in part, STAT6-dependent. These data suggest that the balance of type 1 and type 2 T lymphocyte differentiation is not critical for acute rejection but influences the robust tolerance induced by CD28/B7 blockade in this model.

Background: Renal allograft recipients with diabetes mellitus often demonstrate poorer clinical outcomes than nondiabetic patients. Basiliximab (Simulect), a chimeric anti-interleukin-2 receptor monoclonal antibody, reduced the incidence of acute rejection in renal allograft recipients in 2 multicenter, placebo-controlled, phase III trials., Methods: An analysis of pooled results from the 2 trials was conducted to compare the efficacy and safety of basiliximab with placebo in renal transplant recipients with and without prior diabetes. Patients received either basiliximab (20 mg on day 0 and day 4 posttransplantation) or placebo in combination with cyclosporine for microemulsion (Neoral) and steroids., Results: A total of 722 patients (150 diabetic, 572 nondiabetic) were eligible for intent-to-treat analysis. At 12 months, basiliximab as compared with placebo reduced the proportion of patients experiencing first acute rejection by 41% in diabetics (P<0.01) and by 29% in nondiabetics (P<0.001). Biopsy-confirmed rejection was reduced by 44% in diabetics (P<0.01) and by 26% in nondiabetics (P<0.01). The first acute rejection episode requiring augmented immunosuppression other than steroids was reduced by 49% in diabetics (P<0.01) and by 41% in nondiabetics (P<0.001); death, graft loss, or first rejection episode was reduced by 43% in diabetics (P=0.001) and by 22% in nondiabetics (P<0.01). Superior graft survival was maintained in diabetic recipients treated with basiliximab versus placebo (96% vs. 86%; P=0.022). There were no significant differences in safety between basiliximab and placebo in both diabetic and nondiabetic patients., Conclusions: Basiliximab is associated with a significant reduction in acute rejection and an excellent safety profile in renal transplant recipients with and without diabetes mellitus. Superior graft survival was evident in diabetic patients.

Objective: To evaluate the impact of technical modifications on living-donor liver transplants in children since their introduction in 1989., Summary Background Data: Although more than 4,000 liver transplants are performed every year in the United States, only approximately 500 are performed in children. Living-donor liver transplantation has helped to alleviate the organ shortage for small children in need of liver transplantation. Few centers have amassed a sufficient number of cases to evaluate the impact of the different techniques used in pediatric living-donor liver transplantation., Methods: From 1989 through 1997, 104 primary living-donor liver transplants were performed at the University of Chicago. Three phases of the living-donor liver transplant program can be defined based on the techniques of vascular reconstruction: phase 1, November 1989 to November 1994 (n = 78); phase 2, November 1994 to January 1996 (n = 6); and January 1996 to present (n = 20). The patients' charts were reviewed retrospectively. The incidence and type of vascular complications and patient and graft survival rates were analyzed., Results: Although the demographics of the patients have not changed during the three phases of the living-donor liver transplant program, the outcomes have improved. Without the use of conduits, the incidence of portal vein complications has significantly decreased from 44% to 8%. The incidence of hepatic artery thrombosis has decreased from 22% to 0% with the use of microvascular techniques. The combined use of both techniques has led to a significant increase in graft survival, from 74% to 94%., Conclusions: The living-donor liver transplant recipient operation has undergone significant technical changes since its introduction in 1989. These changes have decreased the vascular complications associated with this type of graft. Avoiding the use of vascular conduits and performing microvascular hepatic artery anastomoses are the critical steps in improving graft survival.

CD28 antagonists have been shown to promote long-term graft survival and induce donor-specific tolerance. In this study, the role of CD28/B7 costimulation and the relative importance of host versus donor B7 expression in allograft rejection was assessed in a murine abdominal vascularized heterotopic heart transplant model. Wild-type, CD28-deficient, or B7-1/B7-2-deficient C57BL/6 (B6) mice were grafted with allogeneic wild type or B7-1/B7-2-deficient hearts. The results demonstrate allogeneic heart grafts survive long-term in mCTLA4Ig-treated B6 and untreated B7-1/B7-2-deficient B6 recipients but not CD28KO B6 mice. B7-1/B7-2KO B6 recipients treated with anti-CD28 (PV-1) or recombinant human IL-2 rejected the heart transplants indicating that these mice are immunologically competent to reject grafts if costimulatory signals are supplied or bypassed. Finally, there was no difference in rejection between normal animals transplanted with wild-type versus B7-1/B7-2-deficient hearts. These results support a critical role for B7-expressing host antigen presenting cells in the rejection of heart allografts in mice and differences among B7KO and CD28KO animals.

Background: The beneficial effects of donor specific transfusion (DST) have become controversial in the cyclosporine era. This study was performed to evaluate the potential benefits of a new protocol for administering DSTs in the perioperative period., Methods: Non-HLA identical living donor kidney transplant recipients were randomized prospectively to control or to receive a DST 24 hr before transplant and 7-10 days posttransplant. All patients received similar immunosuppression according to protocol., Results: The protocol had 212 evaluable patients (115 transfused and 97 control). There were no differences in 1- and 2-year graft and patient survival, causes of graft failure, incidence and types of infection, repeat hospitalization, or the ability to withdraw steroids. Immunological hyporesponsiveness (by mixed lymphocyte culture) occurred more frequently in transfused patients (18%) than controls (3%) (P = 0.04). Blood stored for > or =3 days was associated with fewer early rejections than blood stored < or =2 days. Overall, class II antigen mismatches were associated with more rejection episodes than class I antigen mismatches. However, transfused patients, but not control patients, with more class I antigen mismatches were more likely to have rejections., Conclusions: Administration of DSTs by the method described had no practical influence on patient or graft survival for up to 2 years. However, donor-specific hyporesponsiveness was more common in transfused patients (18 vs. 3%). Longer follow-up will be needed to determine whether DST will be associated with long-term benefit.

Background: HuOKT3gamma1(Ala-Ala) is a genetically-engineered derivative of the parental murine OKT3 monoclonal antibody, in which the six complementarity-determining regions have been grafted within a human IgG1 mAb, and whose C(H)2 region has been altered by site-directed mutagenesis to alter FcR-binding activity, thereby eliminating T cell activation properties. This report describes the results of a phase I trial of huOKT3gamma1(Ala-Ala) treatment of acute renal allograft rejection., Methods: Acute renal allograft rejection in kidney and kidney-pancreas transplant recipients was treated with huOKT3gamma1(Ala-Ala). huOKT3gamma1(Ala-Ala) dosing consisted of daily 5- or 10-mg doses adjusted initially to achieve target levels of 1000 ng/ml., Results: A total of seven patients, five kidney transplant and two kidney-pancreas transplant recipients, were treated with the monoclonal antibody for first rejection episodes. Corticosteroids (500 mg i.v. Solumedrol) were given 2 hr before the first huOKT3gamma1(Ala-Ala) dose only. Banff classification of treated rejections were the following: grade I, 1 patient, grade IIA, 1 patient, grade IIB, 4 patients, and grade III, 1 patient. Median time from transplant to rejection was 15 days, and median follow up 12 months (range 10-17 months). HuOKT3gamma1(Ala-Ala) therapy was given for 10.1+/-2.5 days, and mean total dose was 76+/-27 mg. Rejection was reversed in five of seven patients, and recurrent rejection was observed in one patient. Serum creatinine values peaked on day 1 of huOKT3gamma1(Ala-Ala) therapy, and thereafter demonstrated a progressive decline. Rejection reversal (return of creatinine to baseline) occurred at a median of 4 days and a mean of 4.1+/-2 days. Renal allograft biopsies obtained during huOKT3gamma1(Ala-Ala) therapy provided evidence of rapid rejection reversal. Patient and graft survival were both 100%. First dose reactions were minimal, and anti-OKT3 antibodies were not detected. Elevations in serum IL-10, but not IL-2 levels were observed after the first huOKT3gamma1(Ala-Ala) dose. Marked reductions in circulating CD2+, CD4+, and CD8+ T cells were observed after the first huOKT3gamma1(Ala-Ala) dose, followed by a slow progressive return of cell counts toward pretreatment values. Pharmacokinetic analysis revealed a half-life of 142+/-32 hr., Conclusions: HuOKT3gamma1(Ala-Ala) possesses the ability to reverse vigorous rejection episodes in kidney and kidney-pancreas transplant recipients, and in comparison to murine OKT3, possesses minimal first dose reactions and does not seem to induce antibodies that bind the OKT3 idiotype. These results support the conduct of additional clinical trials with the huOKT3gamma1(Ala-Ala) antibody.