Renal Transplantation With Final Allocation Based on the Virtual Crossmatch.

Solid phase immunoassays (SPI) are now routinely used to detect HLA antibodies. However, the flow cytometric crossmatch (FCXM) remains the established method for assessing final donor-recipient compatibility. Since 2005 we have followed a protocol whereby the final allocation decision for renal transplantation is based on SPI (not the FCXM). Here we report long-term graft outcomes for 508 consecutive kidney transplants using this protocol. All recipients were negative for donor-specific antibody by SPI. Primary outcomes are graft survival and incidence of acute rejection within 1 year (AR <1 year) for FCXM+ (n = 54) and FCXM- (n = 454) recipients. Median follow-up is 7.1 years. FCXM+ recipients were significantly different from FCXM- recipients for the following risk factors: living donor (24% vs. 39%, p = 0.03), duration of dialysis (31.0 months vs. 13.5 months, p = 0.008), retransplants (17% vs. 7.3%, p = 0.04), % sensitized (63% vs. 19%, p = 0.001), and PRA >80% (20% vs. 4.8%, p = 0.001). Despite these differences, 5-year actual graft survival rates are 87% and 84%, respectively. AR <1 year occurred in 13% FCXM+ and 12% FCXM- recipients. Crossmatch status was not associated with graft outcomes in any univariate or multivariate model. Renal transplantation can be performed successfully, using SPI as the definitive test for donor-recipient compatibility.

Syngeneic pancreatic islet transplantation reverses endothelial dysfunction in experimental diabetes.

Diabetes is known to cause impaired endothelium-dependent relaxation of blood vessels. The purpose of this study was to determine whether this endothelial dysfunction is a permanent defect or is reversible after acute arginine supplementation in vitro or by surgical intervention in vivo using syngeneic pancreatic islet transplantation. Lewis rats were injected with streptozotocin to induce diabetes and were studied either 8 or 12 weeks later. Another group received syngeneic islets via intraportal injection at 8 weeks of diabetes and were allowed to become euglycemic for 4 weeks before study. Thoracic aortic rings were tethered in isolated muscle baths, contracted with a submaximal concentration of norepinephrine, and challenged with either the endothelium-dependent vasodilator acetylcholine or the endothelium-independent vasodilator nitroglycerin. Relaxation to acetylcholine (but not nitroglycerin) was reduced in both 8- and 12-week diabetic rings compared with age-matched control rings. Preincubation of diabetic rings in vitro with L-arginine (but not D-arginine) restored relaxation to acetylcholine to normal to rings from 8-week but not 12-week diabetic animals. Plasma basic amino acids (arginine, lysine, and histidine) were reduced by diabetes, whereas other neutral or acidic amino acids were unchanged (phenylalanine, proline, and glutamate), reduced (serine, cysteine, threonine, tyrosine, tryptophan, and aspartate), or elevated (isoleucine, leucine, and valine). Islet transplantation restored to normal the changes in plasma amino acids. Elevation in blood glucose and total glycosylated hemoglobin in diabetic animals was normalized after islet transplantation. Furthermore, islet transplantation completely restored the defective endothelium-dependent relaxation to acetylcholine in diabetic rings.(ABSTRACT TRUNCATED AT 250 WORDS)

Peroxidative stress in diabetic blood vessels. Reversal by pancreatic islet transplantation.

Diabetic complications are believed to arise, in part, through an increase in oxidative stress. We characterized antioxidant status in vascular tissue in untreated diabetic rats and in diabetic rats rendered euglycemic by pancreatic islet transplantation. Three key endogenous antioxidant enzymes (e.g., superoxide dismutase, catalase, and glutathione peroxidase) were measured. Sprague-Dawley rats with streptozotocin-induced diabetes were killed after 8 weeks of untreated hyperglycemia and compared with age-matched controls. Eight weeks of untreated diabetes resulted in a significant increase of tissue catalase in aorta, iliac artery, and femoral artery as compared with controls. No significant changes in either superoxide dismutase or glutathione peroxidase were observed in aorta, iliac artery, or femoral artery of diabetic animals. This increase in catalase in diabetic vascular tissue suggests increased oxidative stress due to chronic exposure to H2O2 in vivo. To assess the impact of islet transplantation on oxidative stress in vascular tissue, inbred Lewis strain rats were rendered diabetic with streptozotocin. After 8 weeks of untreated diabetes, rats received an intraportal islet isograft and were monitored for 4 subsequent weeks of euglycemia. Islet transplantation improved weight gain and normalized blood glucose and total glycosylated hemoglobin. While catalase was significantly increased in aorta and iliac artery at 8 and 12 weeks of diabetes, vascular catalase was restored to normal by islet transplantation. These data suggest that islet transplantation is an effective treatment strategy to minimize increased oxidative stress in diabetic vasculature.

Detection by ESR of DMPO hydroxyl adduct formation from islets of Langerhans.

Electron spin resonance (ESR) spectroscopy together with spin trapping techniques and the application of state-of-the-art loop gap resonators was used to provide a direct measure of spontaneous oxygen radical production by homogenates of freshly isolated and cultured rat pancreatic islets. Using the spin trap agent, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), we were able to detect production by islets of an ESR-sensitive radical signal consisting of a quartet with intensity ratio of 1:2:2:1 and hyperfine splitting of aN = aH = 14.9 Gauss, which is consistent with the DMPO-OH adduct. The amplitude of the signal was decreased by decreasing amount of islets and not detected in the absence of islets. Formation of the DMPO-OH adduct was diminished by the hydroxyl radical scavengers (e.g., ethanol, dimethylsulfoxide, and dimethylthiourea). Only partial attenuation of signal was produced by incubation with an iron chelator or using chelex-treated buffers. The ESR signal was insensitive to the xanthine oxidase inhibitor, oxypurinol, or to superoxide dismutase, but was eliminated in a concentration-dependent manner by either potassium cyanide or catalase (but not heat-inactivated catalase). These observations suggest that the origin of the DMPO-OH arose not from free hydroxyl radicals but primarily from endogenous hydrogen peroxide production perhaps of mitochondrial origin. The development of this technology has implications for the potential measure of oxygen radical production in islet homogenates under pathologic conditions as well as to the application of other cell culture systems.

Electron spin resonance analysis of heme-nitrosyl and reduced iron-sulfur centered complexes in allogeneic, heterotopic cardiac transplants: effects of treatment with pyrrolidine dithiocarbamate.

Inhibition of inducible nitric oxide synthase (iNOS) prolongs allograft survival suggesting a role for nitric oxide (.NO) in allograft rejection. Induction of iNOS is regulated by the oxidant-sensitive, nuclear factor kappa B (NF-kappaB) in many cell types. In the present study using electron spin resonance (ESR) spectroscopy, we evaluated whether pyrrolidine dithiocarbamate (PDTC), a metal chelator and antioxidant, might limit .NO production during the development of rejection in cardiac allografts. We performed either isogeneic (Lewis to Lewis) or allogeneic (Wistar-Furth to Lewis) heterotopic abdominal cardiac transplantation. Allograft recipients received daily injections of PDTC or aminoguanidine (a known inhibitor of iNOS). At postoperative days 4 or 6, grafted and native hearts of transplant recipients were flushed with cardioplegic solution to remove blood contamination. ESR data of allografts revealed a triplet nitrogen signal (aN=17.5 G) and centered at g=2.012 and an additional broad signal at g=2.08. This signal was not seen in either isografts or native hearts of either isograft or allograft recipients. Based upon these parameters, these signals are attributed to nitrosomyoglobin. This signal was inhibited by treatment with aminoguanidine or PDTC. Under these conditions, PDTC also prolonged graft survival from 6.6+/-0.2 to 11.7+/-0.3 days. Thus, it is conceivable that nitrosylmyoglobin formation precedes rejection in cardiac allografts and inhibition of nitrosomyoglobin with agents such as PDTC contribute to improved graft survival.

Antioxidant treatment inhibits activation of myocardial nuclear factor kappa B and inhibits nitrosylation of myocardial heme protein in cardiac transplant rejection.

Nitric oxide production via inducible nitric oxide synthase (iNOS) is believed to play a role in cardiac allograft rejection. Previously, we showed that antioxidants can significantly prolong cardiac graft survival, but the nature of this protection is unknown. In the present study, we examined the protective effect of another antioxidant, dimethylthiourea (DMTU), in a model of cardiac allograft rejection. Specifically, we hypothesized that DMTU would prolong graft survival and decrease activation of nuclear factor-kappa B (NF-kappa B), an important redox-sensitive transcription factor necessary for iNOS gene expression. NF-kappa B was activated by twofold as early as postoperative day 2 in allografts. NF-kappa B activation in allografts progressed to a peak of ninefold by postoperative day and remained increased until postoperative day 6. No activation of NF-kappa B was observed in isografts for comparable time periods. Treatment with DMTU resulted in a significant prolongation of graft survival. This beneficial effect was associated with diminished activation of myocardial NF-kappa B. Treatment with DMTU also resulted in decreased formation of iron-nitrosylprotein complexes as evidenced by electron paramagnetic resonance spectroscopy. These studies provide evidence that reactive oxygen plays a significant role in signal transduction for activation via the transcription factor, NF-kappa B, thereby modulating distal actions and consequences of iNOS-derived nitric oxide.

The Harris Benedict equation reevaluated: resting energy requirements and the body cell mass.

The Harris Benedict equations (HBE) were derived from indirect calorimetric data obtained in 239 normal subjects. Using these data and additional data published by Benedict, which were obtained from subjects spanning a wider age range (n = 98), the present study evaluated the relationship between measured resting energy expenditure and age, sex, and predicted body cell mass (BCM). When the additional subjects from the subsequently published series are included, the regression equations, standard error of the estimate, and 95% confidence limits are similar to the original equations. The HBE estimate resting energy expenditure of a normal subject with a precision of 14%. Resting energy expenditure is directly related to the size of the BCM and is independent of age and sex. The variables of height, weight, age, and sex in the HBE reflect the relationship between body weight and the BCM. Indirect calorimetry and body composition measurements were performed in both normally nourished and malnourished patients (n = 74) to assess the accuracy of the HBE in malnourished patients. Malnutrition is associated with an increase in resting oxygen consumption (VO2) which becomes apparent only when VO2 is expressed as a function of the BCM. There is no difference in resting VO2 between the sexes when expressed as a function of BCM. A regression equation was derived from the Harris Benedict data to predict resting VO2 from age, height, weight, and sex. Predicted VO2 was not significantly different from measured VO2 for the normally nourished patients (n = 33) whereas in the malnourished (n = 41) predicted VO2 underestimated the measured value. The HBE accurately predict resting energy expenditure in normally nourished individuals with a precision of +/- 14%, but are unreliable in the malnourished patient.

Acute torsion of the renal transplant after combined kidney-pancreas transplant.

BACKGROUND: Surgical complications after combined kidney and pancreas transplantation are a major source of morbidity and mortality. Complications related to the pancreas occur with greater frequency as compared to renal complications. The occurrence in our practice of two cases of renal infarction resulting from torsion about the vascular pedicle led to our retrospective review of similar vascular complications after combined kidney and pancreas transplantation. METHODS: Charts were reviewed retrospectively, and two patients were identified who experienced torsion about the vascular pedicle of an intra-abdominally placed renal allograft. RESULTS: Two patients who had received combined intraperitoneal kidney and pancreas transplantation presented at 16 and 11 months after transplant, respectively, with abdominal pain and decreased urine output. One patient had radiological documentation of abnormal rotation before the graft loss; unfortunately, the significance of this finding was missed. Diagnosis was made in both patients at laparotomy, where the kidneys were infarcted secondary to torsion of the vascular pedicle. Both patients underwent transplant nephrectomy and subsequently received a successful second cadaveric renal transplant. CONCLUSIONS: The mechanism of this complication is a result of the intra-abdominal placement of the kidney, length of the vascular pedicle, excess ureteral length, and paucity of adhesions secondary to steroid administration. These factors contribute to abnormal mobility of the kidney. Technical modifications such as minimizing excess ureteral length and nephropexy may help to avoid this complication.

Adenocarcinoma arising in a transplanted pancreas.

Tumor transmission or de novo tumor development in the transplanted organ is a rare event. Appreciation of the organ-specific risk factors for tumor development and careful inspection of the organ at procurement may reduce but not eliminate this complication. We report the first known combined kidney-pancreas recipient who developed adenocarcinoma in the transplanted pancreas. Molecular typing of the tumor by DNA sequencing supports donor derivation of the tumor. Despite cessation of immunosuppression and reconstitution of the recipient's immune response, the patient died from metastatic pancreatic adenocarcinoma. Comparison is made to the reported outcomes after diagnosis of renal cell carcinoma that appeared early after transplantation

Delayed cardiac allograft rejection due to combined cyclosporine and antioxidant therapy.

The effectors of cell death in allograft rejection are poorly understood. Oxygen derived free radicals (ODFR) may participate in graft destruction. We examined the impact of the antioxidants ascorbic acid (AA) and alpha-tocopherol (AT) with low dose CsA on rat cardiac allograft survival. Lewis rats that had undergone heterotopic abdominal cardiac transplantation with Wistar-Furth allografts (day 0) were divided into 6 groups. Group 1 was the control group; groups 2 and 3 received AA (1200 mg/kg), and groups 4 and 5 received AT (800 IU/kg) by gavage daily until rejection. Groups 3, 5, and 6 were given CsA (2.5 mg/kg i.m.) days 1-15. Allograft rejection times (in days) were 7.7 +/- 1, 10.3 +/- 1.5 (P < 0.01 vs. group 1), 37.1 +/- 6.4 (P < 0.01 vs. group 1, P = 0.0004 vs. group 6), 9.0 +/- 1.4, 26.5 +/- 3.6 (P < 0.01 vs. group 1, P < 0.03 vs. group 6), and 20 +/- 4.9 (P < 0.01 vs. group 1) for groups 1, 2, 3, 4, 5, and 6. To assess the impact of AA on ODFR production, chemiluminescence was performed on zymosan-activated Lewis whole blood from control rats and rats administered AA. AA significantly decreased peak chemiluminescence (P < 0.05) as compared with nontreated rats indicating effective ODFR scavenging. To determine whether AA and AT inhibit lymphocyte stimulation, mixed lymphocyte response testing was performed with irradiated Wistar-Furth lymphocytes as stimulator cells for Lew responder cells from rats treated as groups 3, 5, and 6. CsA significantly suppressed (P < .05) proliferation as compared with untreated controls. Neither AA nor AT enhance CsA's immunosuppressive effect by mixed lymphocyte response testing. In summary, prolongation of allograft survival with antioxidants AA and AT does not result from abrogation of lymphocyte responsiveness or alteration in CsA bioavailability. Rather, these data suggest that ODFR are involved in allograft destruction and support a role for effective antioxidant therapy in the treatment of allograft rejection.

Factors influencing weight gain after renal transplantation.

Weight gain following renal transplantation occurs frequently but has not been investigated quantitatively. A retrospective chart review of 115 adult renal transplant recipients was used to describe patterns of weight gain during the first 5 years after transplantation. Only 23 subjects (21%) were overweight before their transplant. Sixty-six subjects (57%) experienced a weight gain of greater than or equal to 10%, and 49 subjects (43%) were overweight according to Metropolitan relative weight criteria at 1 year after transplantation. There was an inverse correlation between advancing age and weight gain, with the youngest patients (18-29 years) having a 13.3% weight gain and the oldest patients (age greater than 50 years) having the lowest gain of 8.3% at 1 year (P = 0.047). Black recipients experienced a greater weight gain than whites during the first posttransplant year (14.6% vs. 9.0%; P = 0.043), and maintained or increased this difference over the 5-year period. Men and women experienced comparable weight gain during the first year (9.5% vs. 12.1%), but women continued to gain weight throughout the 5-year study (21.0% total weight gain). The men remained stable after the first year (10.8% total weight gain). Recipients who experienced at least a 10% weight gain also increased their serum cholesterol (mean 261 vs. 219) and triglyceride (mean 277 vs. 159) levels significantly, whereas those without weight gain did not. Weight gain did not correlate with cumulative steroid dose, donor source (living-related versus cadaver), rejection history, pre-existing obesity, the number of months on dialysis before transplantation, or posttransplant renal function. Posttransplant weight gain is related mainly to demographic factors, not to treatment factors associated with the transplant. The average weight gain during the first year after renal transplantation is approximately 10%. This increased weight, coupled with changes in lipid metabolism, may be significant in terms of altering risk from cardiovascular morbidity.

A prospective randomized comparison of quadruple versus triple therapy for first cadaver transplants with immediate function.

In January 1988, we initiated a prospective, randomized comparison of prophylactic antilymphoblast globulin (ALG; quadruple therapy) versus no prophylactic ALG (triple therapy) in the setting of immediate graft function (defined by a brisk diuresis and a 20% decline in serum creatinine within 24 hr). Recipients were stratified according to presence of diabetes and age greater or less than 50 years. Recipients on quadruple therapy (n = 61) received 7 days of prophylactic Minnesota ALG (5 mg/kg on day 1, 10 mg/kg on day 2, 20 mg/kg on days 3-7). CsA, 10 mg/kg/day, began on day 6. AZA began at 2.5 mg/kg/day and was adjusted according to white blood cell count. Recipients on triple therapy (n = 60) began immediate CsA, 10 mg/kg/day orally and AZA, 5 mg/kg/day, tapering to 2.5 mg/kg/day by day 8. Both groups received identical prednisone tapers beginning at 1 mg/kg/day, decreasing to 0.5 mg/kg/day by 2 weeks and to 0.15 mg/kg/day by 6 months. Demographic characteristics between groups were not different with respect to diabetes, age, sex, race, per cent panel-reactive antibodies (PRA), or HLA matching. Follow-up ranged from 2 to 4.5 years. Patient survival was 93% for the quadruple therapy group and 90% for triple therapy. Actuarial graft survival was 79% in the quadruple group and 72% in the triple group (P = 0.18). Graft loss due to rejection occurred in 6/61 receiving ALG versus 7/60 in the immediate CsA group. Three of 4 high PRA recipients in the immediate CsA group lost their grafts within 30 days compared with none in the ALG group. The mean time to graft loss was significantly longer for the quadruple therapy group (17 +/- 8 months) compared with the triple therapy group (4 +/- 5 months), P = 0.006. The total number of rejection episodes was similar for both groups (29/61 vs. 31/60), as was the number who were rejection free (51% vs. 47%). The use of OKT3 was also similar between groups (28% vs. 30%). The quadruple therapy group had a higher incidence of CMV infection: 20% vs. 7% (P < 0.05), but no grafts or patients were lost as a result. Serum Cr was not different at 1 and 12 months (1.5 and 1.6 vs. 1.6 and 1.7, respectively), nor were Cr clearances (63 and 68 vs. 60 and 63). Conclusion. Early initiation of oral CsA in the setting of immediate graft function is not associated with significant nephrotoxicity.(ABSTRACT TRUNCATED AT 400 WORDS)

NOX 100, a nitric oxide scavenger, enhances cardiac allograft survival and promotes long-term graft acceptance.

BACKGROUND: We examined the role of nitrosative stress in allograft destruction. METHODS: Rats undergoing cardiac transplants received NOX-100, a water-soluble nitric oxide (NO) scavenger with antioxidant properties, with or without low-dose cyclosporine (CsA). Graft survival, NO production, and nuclear factor kappa B (NF-kappaB) activity were studied. RESULT: Using NOX-100 daily until rejection prolonged graft survival (11.6+/-0.6 vs. 7.4+/-0.2 days; P<0.05). Daily low-dose CsA (2.5 mg/kg im) for 7 days or until rejection also prolonged survival (12.6+/-0.5 and 21.6+/-1.6 days, respectively; P<0.01 vs. Controls). Low-dose CsA for 7 days and NOX-100 for 30 days prolonged graft survival (45.0+/-4.7 days; P<0.01 vs. all groups.). NOX-100 had no effect on whole blood CsA levels. Combination therapy until Day 100 resulted in 1 graft loss at Day 116 and indefinite survival in 3 animals (>300 days), which accepted a second WF strain heart without further immunosuppressive therapy but promptly rejected a third party (ACI) cardiac allograft. NOX-100 and CsA reduced nitrate and nitrite, and combination therapy completely normalized NO through to Day 30. Electron paramagnetic resonance spectroscopic analysis demonstrated reduction of signals for nitrosylmyoglobin and nitrosyl-heme with NOX-100 and elimination of signals with CsA alone or combination therapy. Activity of myocardial NF-kappaB decreased with monotherapy vs. untreated allografts. Combination therapy resulted in further inhibition of NF-kappaB up to Day 30. The extent of graft survival correlated with the extent of NO scavenging and NF-kappaB inhibition. Short-term combination therapy had no effect on graft lymphocytic infiltrate on Days 15, 20, and 30. CONCLUSION: These data support a role for both oxidative and nitrosative stress in rejection and the immunoregulatory potential of antioxidant therapy after transplantation.

Recurrent and de novo glomerular disease after renal transplantation: a report from Renal Allograft Disease Registry (RADR).

INTRODUCTION: Short-term and long-term results of renal transplantation have improved over the past 15 years. However, there has been no change in the prevalence of recurrent and de novo diseases. A retrospective study was initiated through the Renal Allograft Disease Registry, to evaluate the prevalence and impact of recurrent and de novo diseases after transplantation. MATERIALS AND METHODS: From October 1987 to December 1996, a total of 4913 renal transplants were performed on adults at the Medical College of Wisconsin, University of Cincinnati, University of California at San Francisco, University of Louisville, University of Washington, Seattle, and Washington University School of Medicine. The patients were followed for a minimum of 1 year. A total of 167 (3.4%) cases of recurrent and de novo disease were diagnosed by renal biopsy. These patients were compared with other patients who did not have recurrent and de novo disease (n=4746). There were more men (67.7% vs. 59.8%, P<0.035) and a higher number of re-transplants (17% vs. 11.5%, P<0.005) in the recurrent and de novo disease group. There was no difference in the rate of recurrent and de novo disease according to the transplant type (living related donor vs. cadaver, P=NS). Other demographic findings were not significantly different. Common forms of glomerulonephritis seen were focal segmental glomerulosclerosis (FSGS), 57; immunoglobulin A nephritis, 22; membranoproliferative glomerulonephritis (GN), 18; and membranous nephropathy, 16. Other diagnoses include: diabetic nephropathy, 19; immune complex GN, 12; crescentic GN (vasculitis), 6; hemolytic uremic syndrome-thrombotic thrombocytopenic purpura (HUS/TTP), 8; systemic lupus erythematosus, 3; Anti-glomerular basement membrane disease, 2; oxalosis, 2; and miscellaneous, 2. The diagnosis of recurrent and de novo disease was made after a mean period of 678 days after the transplant. During the follow-up period, there were significantly more graft failures in the recurrent disease group, 55% vs. 25%, P<0.001. The actuarial 1-, 2-, 3-, 4, and 5-year kidney survival rates for patients with recurrent and de novo disease was 86.5%, 78.5%, 65%, 47.7%, and 39.8%. The corresponding survival rates for patients without recurrent and de novo disease were 85.2%, 81.2%, 76.5%, 72%, and 67.6%, respectively (Log-rank test, P<0.0001). The median kidney survival rate for patients with and without recurrent and de novo disease was 1360 vs. 3382 days (P<0.0001). Multivariate analysis using the Cox proportional hazard model for graft failure was performed to identify various risk factors. Cadaveric transplants, prolonged cold ischemia time, elevated panel reactive antibody, and recurrent disease were identified as risk factors for allograft failure. The relative risk (95% confidence interval) for graft failure because of recurrent and de novo disease was 1.9 (1.57-2.40), P<0.0001. The relative risk for graft failure because of posttransplant FSGS was 2.25 (1.6-3.1), P<0.0001, for membranoprolifera. tive glomerulonephritis was 2.37 (1.3-4.2), P<0.003, and for HUS/TTP was 5.36 (2.2-12.9), P<0.0002. There was higher graft failure (64.9%) and shorter half-life (1244 days) in patients with recurrent FSGS. CONCLUSION: In conclusion, recurrent and de novo disease are associated with poorer long-term survival, and the relative risk of allograft loss is double. Significant impact on graft survival was seen with recurrent and de novo FSGS, membranoproliferative glomerulonephritis, and HUS/TTP.

Recurrent and de novo renal diseases after renal transplantation: a report from the renal allograft disease registry.

Recurrent or de novo glomerular disease is an important cause of graft dysfunction and eventual loss. Cyclosporine A (CyA) has improved short-term renal allograft outcome but has not altered long-term graft survival. The purpose of the current study is to determine the prevalence of such disease and its impact on graft function in the CyA era. From 1984 to 1994, 1,557 renal allografts were performed at the Medical College of Wisconsin and the University of Cincinnati. Patients were followed up for an average of 7.2 years (minimum, 1 year). Recurrent disease was diagnosed by renal biopsy in 98 (6.3%) patients after an average of 36 months. Demographic characteristics of patients with and without recurrent disease were similar. Glomerulonephritis was the most common finding, occurring in 73 patients, and included focal segmental glomerulosclerosis (FSGS), 25; IgA nephropathy (IgAN), 11; membranous (MN), 11; proliferative, 11; membranoproliferative glomerulonephritis (MPGN), 10; glomerular basement membrane (anti-GBM), 3; and systemic lupus erythematosus (SLE), two. Diabetic nephropathy was present in 22, hemolytic uremic syndrome (HUS) in two, and oxalosis in one. Graft loss occurred in 60 of 98 (61%) recipients. Half-life of the allograft was diminished in patients with recurrent disease, 2,038 +/- 225 versus 3,135 +/- 385 days, P = 0.002. The actuarial allograft survival at 1, 3, 5, and 8 years posttransplantation with recurrence was 88%, 74%, 57%, and 34%, respectively; and the corresponding graft survival for patients without recurrent disease was 80%, 70%, 64%, and 53%, respectively (P = 0.003). The risk of recurrent disease increased with length of graft survival from 2.8% at 2 years to 9.8% and 18.5% at 5 and 8 years, respectively. We conclude that recurrent disease is a significant problem after renal transplantation and is associated with decreased graft survival.

Pancreatic transplantation reverses endothelial dysfunction in experimental diabetes mellitus.

BACKGROUND: There is insufficient evidence whether transplantation of the whole pancreas can reverse vascular complications associated with diabetes. In this study we investigated whether pancreatic transplantation in experimental diabetes reverses established defects in endothelium-dependent relaxation. METHODS: Streptozotocin-induced diabetic rats underwent whole-pancreas transplantation after 12 weeks of disease. Endothelial function was evaluated 4 weeks after transplantation and compared with that of control- and age-matched diabetic animals. Blood was taken for analysis of glucose, insulin, total glycosylated hemoglobin, and plasma amino acid levels. Descending thoracic aortas were isolated, sectioned into rings, and mounted in isolated tissue baths. In precontracted rings, endothelium-dependent relaxation to acetylcholine was performed and compared with endothelium-independent relaxation to nitroglycerin as a control. RESULTS: Pancreatic transplantation normalized the increases in glucose and total glycosylated hemoglobin levels and the decrease in serum insulin levels. Diabetes resulted in impaired relaxation to acetylcholine without altering relaxation to nitroglycerin. Pancreatic transplantation completely restored the defective relaxation to acetylcholine without altering the relaxation to nitroglycerin. CONCLUSIONS: These results suggest that pancreatic transplantation selectively improved endothelium-dependent relaxation as opposed to a generalized improvement in vascular smooth muscle reactivity. Furthermore, these studies suggest for the first time that one aspect of vascular complications (i.e., endothelial dysfunction) is amenable to this surgical intervention.

Prognostic value of intraoperative blood flow measurements in vascular access surgery.

BACKGROUND: The purpose of this study was to correlate intraoperative blood flow measurements with outcome in vascular access surgery. METHODS: In 303 patients, 389 vascular access operations were performed. Intraoperative blood flow measurements were made immediately following construction of 227 autogenous and 162 prosthetic arteriovenous fistulas (AVFs) using a handheld flowprobe. Blood flow measurements were stratified by demographic variables such as age, race, sex, and presence of diabetes and were correlated with primary and secondary (assisted) patency. Statistical methods included life-table analysis and Cox proportional hazards model. RESULTS: Blood flow increased progressively from distal to proximal access sites and was not significantly affected by age, race, sex, or presence of diabetes. Autogenous AVFs with flow rates at or below 320 mL/min and polytetrafluoroethylene (PTFE) grafts with flow rates at or below 400 mL/min had significantly worse primary and secondary patency rates compared to their higher flow counterparts at all sites. Using hazard analysis flow rate was the single most important determinant of primary and secondary patency. PTFE grafts with flow rates at or below 400 mL/min also required more interventions (1.58 per patient-year) and failed sooner (median time, 0.5 +/- 4.7 months) than grafts with flow rates above 400 mL/min (1.08 interventions per patient-year; P = .03; median time, 1.6 +/- 5.0 months; P = .003). CONCLUSIONS: Intraoperative measurements of access blood flow provide objective, reliable data that correlate with outcome. Routine use of this technology might lead to more efficient management of patients undergoing hemodialysis access surgery.

Effects of transection and reanastomosis on postprandial jejunal transit and contractile activity.

BACKGROUND: The purpose of this study was to determine how transection and reanastomosis of the intestinal wall influences postprandial motor activity and transit in the small intestine. METHODS: Six dogs were each instrumented with 12 strain gauge transducers, two collection cannulas, and an infusion catheter defining a 100 cm study segment in the midjejunum. The animals underwent baseline measurements of postprandial motor activity and transit rate after 650 kcal solid and liquid meals. Postprandial motor activity was analyzed by computer methods that identify frequency, duration, amplitude, and propagation behavior of smooth muscle contractions. After the baseline measurements were performed, each animal underwent transection and reanastomosis of the intestinal wall at sites marked during the initial laparotomy. Measurements of postprandial motor activity and transit were repeated and compared with control values. RESULTS: Transection decreased frequency, amplitude, and percent propagation for postprandial contractions. Total propagating area per minute significantly decreased from 382 +/- 20 gram-seconds/minute to 190 +/- 66 gram-seconds/minute after transection (p < 0.05). Intestinal transit decreased from 13.5 +/- 1.5 cm/min to 8.5 +/- 2.4 cm/min (p < 0.05). The change in transit was related primarily to a change in frequency of propagating contractions (r = 0.767; p = 0.004). CONCLUSIONS: Transection and reanastomosis of the intestinal wall changes the temporal and spatial organization of contractions distal to the transection site. The net result is fewer distally propagating contractions and slower intestinal transit.

Postprandial motor activity and its relationship to transit in the canine ileum.

BACKGROUND: The purpose of this study was to elucidate the mechanism of reduced intestinal transit rate in the ileum as compared with the jejunum. METHODS: Twenty-one dogs were each instrumented with 12 strain gauge transducers, 2 collection cannulas, and an infusion catheter defining a 100 cm study in the midjejunum (n = 11) and midileum (n = 10). Postprandial motor activity and intestinal transit were measured 1 hour after ingestion of a 650 kcal solid meal. Contractile activity was analyzed by means of computer programs that determine frequency, amplitude, and propagation behavior of circular smooth muscle contractions. RESULTS: Postprandial ileal contractions occurred with greater frequency (13.7 +/- 2.5 versus 11.5 +/- 0.4; p = 0.04) and displayed a higher incidence of propagation (61% +/- 2% versus 44% +/- 3%; p = 0.0001) than jejunal contractions, but traveled at significantly slower rates (1.0 +/- 0.7 cm/sec vs 3.7 +/- 0.9 cm/sec; p = 0.0001). The net result was significantly slower transit in the ileum compared with the jejunum (4.7 +/- 0.7 cm/min versus 13.1 +/- 1.5 cm/min; p = 0.0006). Within each region, transit correlated with parameters of propagating contractions. Stepwise regression of the combined data revealed that contraction velocity was the most important variable determining intestinal transit rate (r = 0.64; p < 0.001). CONCLUSIONS: Contrary to previous thinking, postprandial ileal contractions display a high degree of temporal and spatial organization. Slow ileal transit is mainly due to reduced propagation velocity, which is intrinsic to the circular smooth muscle.

Effects of intestinal transplantation on postprandial motility and regulation of intestinal transit.

BACKGROUND: The effects of intestinal transplantation on gut motility have not been completely defined. In this study we examine the effects of ileal transplantation on ileal smooth muscle contractility, together with gastroduodenal emptying, intestinal flow, and transit rates in a canine model of short-gut syndrome. METHODS: Animals (n = 22) were instrumented with strain gauge transducers, collection cannulae, and infusion catheters to assess motility, intestinal flow and transit rates, and gastroduodenal emptying. Ten animals served to define normal parameters. Six animals underwent a 70% resection of the proximal small intestine to serve as short-gut controls. Six animals underwent removal of a 100-cm segment of the ileum, with cold storage, and autotransplantation the following day combined with a 70% resection of proximal bowel. RESULTS: Transplant animals exhibited delayed gastroduodenal emptying, reduced intestinal flow rates, and postprandial phasic contractions that were similar to short-gut controls. However, transplant animals experienced rapid intestinal transit compared with short-gut controls (4.8 +/- 0.4 cm/min vs 2.0 +/- 0.3 cm/min; mean +/- SEM; P <.05). CONCLUSIONS: The transplanted intestine, even with 18 hours of cold storage, exhibits a relatively normal postprandial motor response. However, adaptive responses of the transplanted intestine, such as regulation of intestine transit, may be impaired by neuromuscular injury associated with denervation or ischemia.