Scintillation and radioluminescence mechanism in ß-Ga2O3 semiconducting single crystals.

In this paper, we present the results of experiments on samples of ß-Ga2O3 single crystals under a project aimed at assessing and improving the scintillation performance of this material by studying scintillation and radioluminescence mechanism and its limitations. In addition to standard experiments, such as scintillation light yields and time profiles, radio-, and thermoluminescence, we developed and tested a new and promising two-beam experiment, in which a sample is excited by an X-ray beam and additionally stimulated by an IR laser diode. Fe and Mg doping compensate for the inherent n-type conductivity of ß-Ga2O3 to obtain semi-insulating single crystals for large-area substrates and wafers. At the same time, residual Fe and Ir are ubiquitous uncontrolled impurities leached from the Ir crucibles used to grow large bulk crystals by the Czochralski method. For these experiments, we selected four samples cut from the Czochralski grown 2-cm diameter ß-Ga2O3 single crystal boules; one with a reduced Fe content, two unintentionally Fe- and Ir-doped (UID) with lower and higher Fe content, and one doped with Mg. We find that steady-state radioluminescence spectra measured at temperatures between 10 and 350 K are dominated by the UV emission peaking at about 350-370 nm. Unfortunately, even for the best sample with a reduced Fe-content, the intensity of this emission drops precipitously with the temperature down to about 10 % at 300 K. From the two-beam experiments, we conclude that recombination via inadvertent Fe impurity involving three charge states (2+, 3+, and 4+) may reduce a steady-state UV emission of ß-Ga2O3 under X-ray excitation by as much as 60-70 %, one-third to one-half of which is due to the recombination (specific for Fe-doped ß-Ga2O3) involving the 4+ and 3+ charge states of Fe and the remaining 50-70 % being due to a more familiar route typical of other oxides, involving the 2+ and 3+ charge states of Fe. These losses are at higher temperatures enhanced by a thermally activated redistribution of self-trapped holes (STHs). In addition, the trapping of electrons by Fe and holes by Mg, Fe, and Ir may be responsible for scintillation light loss and reduction of the zero-time amplitude essential for the fast timing scintillation applications. Despite indirect evidence of competitive recombination in ß-Ga2O3 involving a deep Ir3+/4+ donor level, we could not quantitatively assess losses of the UV steady state radioluminescence light due to the inadvertent Ir impurity.

Therapeutic Problems and Pregnancy in a Patient With Infantile Nephropathic Cystinosis: A Case Report.

BACKGROUND: Cystinosis is a rare genetic disorder characterized by the abnormal accumulation of cystine in the lysosomes of various tissues and organs leading to their dysfunction. The most common type is the infantile nephropathic cystinosis which without treatment leads to renal failure and before the introduction of cysteamine was the cause of death before puberty. CASE PRESENTATION: A 27-year-old female patient with infantile cystinosis developed end-stage renal disease at the age of 10. The first kidney transplantation from patient's father was carried out at the age of 12. The recurrent urinary tract infections led to the graft failure after 6 years. Following the removal of right appendages due to the ovarian tumor, the patient underwent the second kidney transplantation from her mother at the age of 19. After the transplantation, the cysteamine treatment was irregular due to limited availability of the medicine. When it became regular in 2017 the patient did not tolerate full doses. Despite elevated blood levels of cystine and the removal of right appendages, the patient naturally became pregnant in August 2017. Except for recurrent urinary tract infections, the renal parameters remained normal throughout the entire pregnancy. However, in the 32nd week of gestation, due to preeclampsia a caesarean section was performed. A healthy daughter was born, 1400/41 and with a 9 point Apgar score. CONCLUSIONS: Due to the possibility of treatment with cysteamine and kidney transplantations, patients with cystinosis live longer and their quality of life improves. These female patients can even naturally become pregnant and give birth to healthy children.

Melt growth and properties of bulk BaSnO3 single crystals.

We present the first-time growth of bulk BaSnO3 single crystals from the melt by direct solidification, their basic electrical and optical properties as well as their structural quality. Our measurement of the melting point (MP) of BaSnO3 amounts to 1855 °C ± 25 K. At this temperature an intensive decomposition and non-stoichiometric evaporation takes place as the partial pressure of SnO(g) is about 90 times higher than that of BaO(g). X ray powder diffraction identified only the BaSnO3 perovskite phase, while narrow rocking curves having a full width at half maximum of 26 arcsec and etch pit densities below 106 cm-2 confirm a high degree of structural perfection of the single crystals. In this respect they surpass the structural properties of those single crystals that were reported in the literature. The electrical conductivity of nominally undoped crystals depends on the growth conditions and ranges from insulating to medium n-type conductivity. After post-growth annealing in an oxidizing atmosphere undoped crystals are generally insulating. Doping the crystals with lanthanum during growth results in a high n-type conductivity. For a La doping concentration of 0.123 wt.% we measured an electron concentration of 3.3 × 1019 cm-3 and an electron mobility of 219 cm2 V-1 s-1. Based on optical absorption measurements we determined an energy of 3.17 ± 0.04 eV at 5 K and of 2.99 ± 0.04 eV at 297 K for the indirect band gap of BaSnO3.

Treatment of Persistent Hypercalcemia and Hyperparathyroidism With Cinacalcet After Successful Kidney Transplantation.

INTRODUCTION: Hypercalcemia caused by persistent hyperparathyroidism after successful kidney transplantation (KT) is a common problem and may negatively affect graft function, bone metabolism and the cardiovascular system. Cinacalcet is a novel, available tool to control hypercalcemia after KT. The aim of the study was to examine the efficacy of cinacalcet in lowering calcium in KT recipients with persistent hypercalcemia owing to hyperparathyroidism. METHODS: In this retrospective observational study, we analyzed 30 patients with persistent hypercalcemia >10.8 mg/dL. All patients in the study were started on cinacalcet at different points after KT, with the mean time of 43 ± 37 months. The initial dose of 30 mg/d was adapted progressively based on serum calcium levels. RESULTS: During the observation period, graft function in all patients was stable (estimated glomerular filtration rate [Chronic Kidney Disease Epidemiology Collaboration formula] 64 ± 25 mL/min/1.73 m(2)). The mean baseline calcemia was 11.9 ± 0.7 mg/dL, the intact parathyroid hormone value was 490 ± 228 pg/mL and phosphorus concentration was 2.2 ± 0.5 mg/dL. Treatment with cinacalcet resulted in a significant decrease in serum calcium level (mean, 9.9 ± 0.7 mg/dL; P < .001), a reduction in intact parathyroid hormone level (308 ± 199 pg/dL; P < .001), and an increase in phosphorus concentration (mean, 2.8 ± 0.6 mg/dL; P < .001). In 5 females, gastrointestinal side effects were observed, requiring withdrawal of cinacalcet in 1 case. CONCLUSIONS: Cinacalcet administered after KT seems to be an effective option for the management of persistent hypercalcemia owing to hyperparathyroidism with satisfactory tolerability and may be considered as a therapeutic alternative to surgical parathyroidectomy or as a bridging therapy to parathyroidectomy.

Does the Parathyroidectomy Endanger the Transplanted Kidney?

BACKGROUND: Some investigators maintain that a parathyroidectomy (PTX) performed for tertiary hyperparathyroidism may potentially cause graft malfunction or even loss of the transplanted kidney after the operation. The goal of this study was to determine if parathyroidectomy affects transplanted kidney function. METHODS: The study group consisted of 48 renal graft recipients who underwent operation due to tertiary hyperparathyroidism. Thirty-nine subtotal parathyroidectomies and 9 more selective, less than subtotal parathyroidectomies were performed. The estimated glomerular filtration rate (eGFR) was calculated retrospectively on days 2 to 3 and 4 to 5 and at 1, 3, 6, 12, 24, and 36 months after PTX; these findings were compared with preoperative values. The cumulative graft survival rate in the postoperative period was assessed. RESULTS: In the follow-up period, 4 of 48 patients returned to hemodialysis (after 1, 7, 22, and 57 months after PTX). In the first case, the patient had stopped taking the immunosuppressive drugs 1 month after PTX. Cumulative graft survival rate after PTX was 98.0% after 6 months, 96% after 12 months, and 93% after 2 and 3 years. The mean preoperative eGFR was 52 ± 17.15 mL/min/1.73 m(2), and the median was 48.28 mL/min/1.73 m(2). Overall and in the subtotal parathyroidectomy group, eGFR was significantly lower (P < .001) only on days 2 to 3. There were no differences between preoperative and postoperative eGFR values in the other follow-up periods. In the more selective, less than subtotal parathyroidectomy group, the decrease in eGFR values was nonsignificant compared with preoperative findings in the early postoperative period as well as in all follow-up periods. CONCLUSIONS: In this study, PTX did not significantly impair transplanted kidney function, but in the early postoperative period, transient reductions in graft function did occur.

Usefulness of Modified Dindo-Clavien Scale to Evaluate the Correlation Between the Severity of Surgical Complications and Complications Related to the Renal and Pancreatic Grafts After Simultaneous Kidney and Pancreas Transplantation.

OBJECTIVE: Simultaneous pancreas and kidney transplantation (spktx) is the multiorgan transplantation. Thus various complications originated from transplanted organs and the complications that are not directly related to pancreatic or renal grafts could be developed at the same recipient. AIM: The aim of this study is to explore whether there is a correlation between the severity of complications originated from transplanted pancreas, transplanted kidney and general surgical complication developed at the same spktx recipient. METHODS: Complications which developed among 112 spktx recipients were divided into three groups: related to the pancreatic graft (PTXc), to the renal graft (KTXc) and the general surgical complication (GNc). Severity of postoperative complications using modified Dindo-Clavien scale recipients was evaluated for each group. The correlation of severity of coexisting complications from different complication groups was analyzed. RESULTS: There were 22 recipients who developed the coexistence of complication between different complication groups. Complication originated from two and three complication groups developed 15 (68.2%) and 7 (31.8%) patients, respectively. There was not found correlation of the complication severity between: KTXc and GNc group, GNc and PTXc group, KTXc and PTXc group. The correlation (r = 0.84) of complication severity in recipients who developed concurrently complication from transplanted kidney, transplanted pancreas and general surgery complication was found. CONCLUSION: The modified Dindo-Clavien scale is an useful methodology for the correlation description of complication severity in complex multiorgan transplantation such is spktx, especially when the complications originated from different, potentially independent from the pathophysiological point of view, sources.

Surgical Complications Not Related to the Renal and Pancreatic Grafts After Simultaneous Kidney and Pancreas Transplantation.

BACKGROUND: Simultaneous pancreas and kidney transplantation (SPKTx) is the most commonly performed multiorgan transplantation procedure worldwide. Transplanted organs are the main source of complication; however, some postoperative complications are not directly related to the pancreatic or renal grafts. The goal of this study was to evaluate the prevalence, type, and severity of postoperative complications not related to transplanted kidney or pancreas among SPKTx recipients. METHODS: Complications unrelated to transplanted pancreas and kidneys among 112 SPKTx recipients were analyzed. The cumulative freedom from general surgical complications was assessed, and it was compared with cumulative freedom from complications related to kidney and pancreatic grafts. Severity of complications was classified according to a modified Clavien-Dindo scale. RESULTS: The general surgery complication rate was 22.2%. Cumulative freedom from general surgical complications at days 60 and 90 after transplantation was 0.89 and 0.87, respectively. Cumulative freedom from general surgical complications was comparable with cumulative freedom from complications related to kidney grafts but significantly higher than cumulative freedom from complications related to pancreatic grafts (log-rank test, P < .001). The rates for grades of severity II, IIIa, IIIb, and IVb were 19.4%, 9.7%, 64.5%, and 6.4%, respectively. The most frequent cause of complications was intra-abdominal hematoma or abscess (25.8%). CONCLUSIONS: The general surgical complication rate was comparable to the rate of complications originating from the renal grafts but significantly lower than the complication rate related to the transplanted pancreas. The incidence of general surgical complications could be defined as moderate, and the severity of this type of complication was low.

Multivariate analysis of complications after simultaneous pancreas and kidney transplantation.

OBJECTIVE: Identification of factors that have an impact on postoperative complications after simultaneous pancreas and kidney transplantation (SPKTx) could help overcome limitations of this kind of treatment. METHODS: Postoperative complications among 112 SPKTx recipients were divided into 3 groups: related to transplanted pancreas (n = 66), related to transplanted kidney (n = 23) and general surgical complications (n = 31) 120 refers to complications among 112 recipients. According to the modified Clavien-Dindo scale, complications were classified according to their severity for each group. Risk factors for complication development related to donor, recipient, surgical technique, and immunosuppression were included to establish the multivariable model using logistic regression. RESULTS: Multiple regression analysis showed the following independent factors influenced mortal complications due to transplanted pancreas: age of donor (OR, 1.07; P < .04), duration of vascular pancreas anastomosis above 35 minutes (OR, 3.94; P < .04) and duration of recipient dialysis above 24 months before transplantation (OR, 0.14; P < .01). Area under receiver operating characteristic curve for this model was 0.8. CONCLUSION: To improve results, the following modification of identified risk factors should be assumed: selection of donor in term of age, shortening of the second warm ischemia time, and adjustment of the waiting list to avoid prolongation of recipient dialysis before SPKTx.

Early complications related to the transplanted kidney after simultaneous pancreas and kidney transplantation.

OBJECTIVE: Simultaneous pancreas and kidney transplantation (SPKTx) is the most often performed multiorgan transplantation. The main source of complication is transplanted pancreas; as a result, early complications related to kidney transplant are rarely assessed. The aim of this study was to evaluate prevalence, types, and severity of postoperative complications due to kidney graft among the simultaneous pancreas and kidney recipients. METHODS: Complications related to transplanted kidney among 112 SPKTx recipients were analyzed. The indication for SPKTx was end-stage diabetic nephropathy due to long-lasting diabetes type 1. The cumulative survival rates for kidney graft function and cumulative freedom from complication on days 60 and 90 after transplantation were assessed. Severity of complications was classified according to the modified Dindo-Clavien scale. RESULTS: The 12-month cumulative survival rate for kidney graft was 0.91. Cumulative freedom from complication on the 60th day after transplantation was 0.84. The rates for II, IIIA, IIIB, IVA, and IVB severity grades were: 34.9%, 4.3%, 26.1%, 26.1%, and 8.6%, respectively. Acute tubular necrosis and rejection were the most frequent (43.4%) cause of complication. The most frequent reasons for graft nephrectomy were infections (2/7; 28.6%) and vascular thrombosis due to atherosclerosis of recipient iliac arteries (2/7; 28.6%). The most severe (IVB) complications were caused by fungal infection. CONCLUSION: Rate and severity of complications due to renal graft after SPKTx was low; however, to prevent the most serious ones reduction of fungal infection was necessary.

Surgical complications related to transplanted pancreas after simultaneous pancreas and kidney transplantation.

OBJECTIVE: Simultaneous pancreas and kidney transplantation (SPTKx) is characterized by the high rate and variability of postoperative complications, which could be a limitation of this treatment. The aim of this study was to evaluate prevalence, types, and severity of postoperative complications due to pancreas graft among the simultaneous pancreas and kidney recipients. METHODS: Postoperative complications related to transplanted pancreas among 112 SPTKx recipients were analyzed. The cumulative survival rates for pancreas graft function and cumulative freedom from complication on day 60 after transplantation were assessed. Severity of complications was classified according to a modified Clavien-Dindo scale. RESULTS: The 12-month cumulative survival rate for pancreatic graft was 0.74. Cumulative freedom from complication on the 60th day after transplantation was 0.57. The rates for II, IIIA, IIIB, IVA, and IVB severity grades were 10,6%, 4,5%, 19,7%, 44%, and 21,2%, respectively. The most severe (IVB) transplanted pancreas complications were due to graft inflammation, infection, pancreatic abscess, and local or diffuse necrosis. The most frequent reason for graft pancreatectomy was vascular thrombosis 35.9% (14/39). The mortality rate after graft pancreatectomy was significantly lower for vascular thrombosis than for infection (0/14 vs 11/25; P < .05). CONCLUSION: Reducing vascular thrombosis could preserve graft function rate. Preventing graft inflammation and infection would reduce mortality.

When less is more--case report of successful renal transplantation from a living unrelated donor to a high-risk female recipient.

Qualification for kidney transplantation for patients with a long history of renal replacement therapy and numerous medical complications requires individual analysis of all contraindications and limitations as well as advantages of the procedure. In this case report, we analyze the qualification process and posttransplantation course of a 28-year-old female patient with end-stage renal failure due to reflux nephropathy, treated with renal replacement therapy since early childhood, who received her second kidney transplant with glomerular filtration rate <40 mL/min/1.73 m(2) from a living, unrelated donor in 2009. Despite the high risk of immunological and surgical complications, transplanting organs of borderline excretory capacity, and no human leukocyte antigen matching, significant health benefits were achieved. Procurement of a kidney with borderline filtering function reduces the risk of potential negative consequences of impaired remnant filtration in the living donor. Following the principle of procuring a kidney with worse parameters from the living donors, it is necessary to perform an examination evaluating the function of each kidney. Procurement of a kidney with significantly worse parameters requires an individual assessment of benefits for the recipient.

Uridine diphosphate glucuronosyltransferase 2B7 variant p.His268Tyr as a predictor of kidney allograft early acute rejection.

BACKGROUND: Uridine diphosphate glucuronosyltransferase (UGT2B7) is responsible for conversion of mycophenolic acid to mycophenolic acyl-glucuronide (acylMPAG). Conflicting data exist regarding the role of UGT2B7 p.His268Tyr (802C>T, rs7439366) variant in the clinical course following organ transplantation. STUDY AIM: The aim of this study was to reveal an association between UGT2B7 p.His268Tyr (802C>T, rs7439366) polymorphism and kidney transplantation outcome. STUDY DESIGN, PATIENTS, AND METHOD: Genomic DNA of 235 kidney transplant recipients was genotyped for UGT2B7 802C>T using TagMan single nucleotide polymorphism (SNP) genotyping assay. Maintenance immunosuppression used mycophenolate mofetil (MMF) and cyclosporine A (n = 137) or tacrolimus (n = 98). Primary end-point was biopsy-confirmed acute rejection within 3 and 12 post-transplantation months. Secondary end-points included gastrointestinal side effects, leukopenia, lymphopenia, neutropenia, and infections. Statistical analysis was performed with the aid of SAS System using kernel-smoothed estimates of acute graft rejection hazard function. The log-rank test and hazard ratio were used to reflect association between UGT2B7 802C>T variant and risk of acute graft rejection. RESULTS: Within 3 postimplantation months 38 (16.2%) patients experienced acute rejection; 33 were allele C carriers in UGT2B7 802C>T SNP and 5 were TT homozygotes (P < .0457). Allele C-associated risk of rejection was 2.50 and remained between 2.19 and 3.02 after adjustment for clinical confounders, ie, HLA mismatch, panel-reactive antibodies, donor age, repeated transplantation, induction therapy, donor type, delayed graft function, applied calcineurin inhibitor, or MMF dosing. We found no association between the polymorphism and gastrointestinal side effects, leukopenia, lymphopenia, neutropenia, and infections. CONCLUSION: UGT2B7 802C>T genotyping may help identify patients with excessive early acute rejection risk.

Is severe atherosclerosis in the aortoiliac region a contraindication for kidney transplantation?

BACKGROUND: Atherosclerosis is common in end-stage renal disease patients on dialysis. However, it has previously been considered to be a relative contraindication to kidney transplantation. Currently, patients with extended indications are accepted onto the waiting list, including those with severe atherosclerosis. These patients require vascular procedures before or during kidney transplantation. The aim of this study was to present our experience with vascular reconstruction before kidney transplantation. MATERIAL AND METHODS: Twelve atherosclerotic, uremic patients referred to be candidates for kidney transplantation were refused because of occlusive lesions of the iliac arteries or the distal aorta. The 10 males and 2 females had an age range of 45 to 68 years. Preoperative assessments consisted of a Doppler ultrasound and an angio computed tomography scan. The reconstructions were performed with aorto-biliac, aorto-bifemoral, or ilio-femoral dacron grafts in 7, 4, and 1 patient, respectively, under general anesthesia. RESULTS: There were no major postoperative complications; the patients were discharged and placed on a special waiting list. Eight patients received kidney allografts, including one living-related transplantation. All procedures were performed with arterial anastomosis of the transplanted kidney to the side of the prosthesis. No patient developed signs of arterial graft infection. In the postoperative period, there were no arterial or transplanted kidney-related complications, except for delayed graft function in four cases. The remaining four patients are still on the waiting list. CONCLUSION: In end-stage renal disease patients with severe atherosclerosis in the aortoiliac region, vascular reconstruction allows kidney transplantation.

Tolerance of enteric-coated mycophenolate sodium in combination with calcineurin inhibitor in kidney transplant recipients: Polish experience.

INTRODUCTION: Enteric-coated mycophenolate sodium (EC-MPS) was developed to reduce the incidence of gastrointestinal adverse effects. This multicenter observational study was designed to evaluate the safety profile and drug tolerance in kidney transplant recipients. METHODS: Three hundred adult kidney recipients (median age 48 years) were enrolled over 3 years to receive EC-MPS de novo (n=175), as a switch from azathioprine (n=62) or mycophenolate mofetil MMF (n=63); in combination with calcineurin inhibitor. Drug doses, serum creatinine, estimated glomerular filtration rate (eGFR), as well as drug tolerance, patient and physician evaluation of therapy (on a 4-point scale) were recorded at enrollment and followed over 28 weeks. We modeled the probability of the highest level (ie, best result) of the categorical outcome variable. RESULTS: Two hundred seventy-three patients completed the study (91%). In the pooled study group (1) best drug tolerance was expected more frequently with tacrolimus versus cyclosporine (odds ratio [OR] 2.12, P<.05); (2) best physician evaluation, with earlier EC-MPS introduction (OR for 4-week delay: 0.99, P<.03) and higher eGFR (OR for 5 mL/min increase: 1.21, P<.01). Among the EC-MPS de novo administrations group: (1) best drug tolerance was expected more frequently with coadministered tacrolimus versus cyclosporine (OR 3.14, P<.02); (2) best patient evaluation, with higher eGFR (OR for 1 mL/min increase: 1.04, P<.04); and (3) best physician evaluation, with higher eGFR (OR for 1 mL/min increase: 1.04, P<.001) and earlier EC-MPS introduction (OR for 4-week delay: 0.99, P<.03). In the conversion from MMF to EC-MPS group: (1) best drug tolerance was expected less frequently with coadministered cyclosporine versus tacrolimus (OR 0.05, P<.04) and more frequently with younger recipients (OR .001, P<.04); (2) best physician evaluation was expected more frequently with lower EC-MPS dose (OR for 360-mg dose increase: 0.4, P<.01) and with higher eGFR (OR for 5 mL/min increase: 1.42, P<.002). Adverse events were reported among 49/300 patients (16 serious adverse events). CONCLUSIONS: EC-MPS was tolerated better by younger kidney recipients, when combined with tacrolimus versus cyclosporine, and when introduced earlier after transplantation. EC-MPS tolerance decreased gradually with renal function deterioration.

Influence of simultaneous pancreas and preemptive kidney transplantation on severity of postoperative complications.

BACKGROUND: Simultaneous pancreas and preemptive kidney transplantation (SPpreKT) seems to be the optimal treatment for the patients with diabetes type 1 who are progressing to end-stage renal disease. On the other hand, surgical complications with a high rate of relaparatomy are a limiting factor in pancreas transplantation. OBJECTIVE: Comparison of severity of surgical complications was performed between a group of preemptive (SPpreKT group) and nonpreemptive recipients of SPKT (SPKT group). METHODS: Between 1988 and 2010, we performed 112 SPKTs including 25 preemptive recipients (22.3%). The SPKT Group included 87 recipients (77.7%). The severity of complications was classified according to a modified Clavien scale: grade I, no complication; grade II, drug therapy; grade IIIA, invasive intervention not requiring general anesthesia; grade IIIB, invasive intervention requiring general anesthesia; grade IVA, graft failure; and grade IVB, death. RESULTS: Among the SPpreKT group, 64% of recipients were free from postoperative complications compared with 40.3% of the SPKT group (P<.01). Among the SPKT group, 52 recipients (59.7%) developed 58 postoperative complications, including 15 (17.3%) deaths due to graft pancreatitis (80%) or pancreatic fistula (20%). Among the SPpreKT group, 9 recipients developed 9 complications. None of the preemptively transplanted group subjects experienced a lethal complication. Among the SPpreKT group, the most severe complication was graft pancreatitis leading to graft removal in 2 recipients. CONCLUSIONS: Recipients of preemptive SPKT developed significantly fewer postoperative complications, especially deaths. However the rates of mild (II, IIIA) and moderate (IIIB) complications as well as graft failures (IVA) were similar to the nonpreemptive group.

Vascular access for haemodialysis in patients with central vein thrombosis.

OBJECTIVES: Dialysis-dependent patients often have central venous drainage complications. In patients with functioning arm arteriovenous fistula, this may result in venous hypertension, arm oedema and vascular access failure. Percutaneous angioplasty and stent implantation might be inadequate to resolve these issues. In these cases, new access can potentially be created with anastomosis to the subclavian vein, iliac vein or vena cava or by making a veno-venous graft to bypass the thrombosis. The aim of this study was to assess the utility of unusual bypasses in vascular access in patients with the central vein thrombosis. MATERIALS: A total of 49 patients were treated. The mean number of previous vascular access surgery procedures was 7.6 (3-17). We performed 19 axillo-iliac, 14 axillo-axillary bypasses and 16 conduits from the arm fistula to the jugular (nine conduits) or subclavian (seven conduits) vein for haemodialysis purposes. RESULTS: All fistulas except one were used for haemodialysis. One patient died before the first use of the fistula. At 12 months, the primary, primary assisted and secondary patency rates were 85.4%, 89.6% and 95.8%, respectively. The follow-up period ranged from 1 to 84 months. CONCLUSION: Unusual grafts are an efficient option as a permanent vascular access for haemodialysis purposes in patients with central vein occlusion.

Transplant glomerulopathy: clinical and pathological correlations.

OBJECTIVE: Chronic transplant glomerulopathy (TG) is one of the leading causes of severe posttransplantation proteinuria and graft loss. Our current knowledge about risk factors for the development of TG, as well as factors that affect its dynamics and prognosis, is poor. We sought to describe the pathological and clinical risk factors and correlations of TG as well as parameters that influenced the survival of grafts with that pathology. MATERIALS AND METHODS: We retrospectively reevaluated 86 kidney transplant cases with TG that have been recognized on the basis of an indication biopsy since 1997. All TG as well as all pre-TG (previous) biopsies were characterized for the presence of C4d deposits in the graft. RESULTS: Younger recipient age and minimal immunosuppression due to drug withdrawal or suboptimal drug doses/blood levels within 3 to 6 months preceding the biopsy were associated with C4d deposition in peritubular capillaries (PTC; P = .0053 and P = .0365, respectively). Diffuse PTC-itis (P = .029, RR [95% confidence interval] = 3.349 [1.131-9.919]) and total interstitial inflammation score (P = .015, RR [95% confidence interval] = 9.662 [1.784-52.329]) were observed to show a negative impact on graft survival. C4d deposition in PTC and glomeruli, the level of pretransplantation sensitization, episodes of acute rejection, and C4d in previous (pre-TG) biopsies did not influence the survival of grafts with TG. CONCLUSIONS: Younger recipient age and minimal immunosuppression were associated with C4d positivity in grafts with TG. The survival of kidney grafts with TG was significantly affected by the magnitude of inflammation in the interstitium and PTC, but not by C4d positivity in PTC and glomeruli.

Influence of pancreas and kidney transplant function on recipient survival.

The aim of this study was to evaluate long-term survival after simultaneous pancreas and kidney (SPK) transplantation in relation to function of both grafts. Among 67 recipients who received SPK transplants between 1988 and 2004, 35 had follow-up longer than 18 months, and were divided into: group I (n = 20), recipients with good function of both grafts; group II (n = 7), patients who had lost transplanted pancreas but had still good kidney graft function; group III (n = 8), patients who had lost both grafts. Comparison of survival rates and analysis of the reason of mortality among groups was performed. The cumulative survival rate was significantly higher in group I than in group III (after 3, 5, 10 years: 100%, 100%, 80% vs 75%, 50%, 37%, respectively). Cumulative survival rate for group II after 3, 5, 10 years was 100%, 100%, 33%, respectively. There were no significant differences in survival rates between groups I and II and between groups II and III. In group I deaths for cardiovascular event and for leukemia were noted. In group II deaths due to cardiovascular event and sepsis were observed. In group III all patients died due to cardiovascular events and the mean time from loss of pancreas and kidney graft function to death was: 75 +/- 51 months (range from 19 to 142), and 49 +/- 26 months (range 19 to 99), respectively. Good pancreas and kidney graft functions prevent death due to cardiovascular event.

A solution to organ shortage: vascular reconstructions for pancreas transplantation.

Multiorgan harvesting (MOH) accounts for approximately 40% of all organ procurements in Poland. Simultaneous procurement of the pancreas and liver necessitates division of the vessels supplying both organs. Therefore, reconstruction of the pancreas vasculature is mandatory for proper function of the transplanted organ. The aim of this study was to present various methods of vascular reconstruction to prepare the pancreas for transplantation. Between January 1999 and April 2005, among 42 whole pancreas transplantations, 35 came from MOH necessitating arterial reconstruction. In 32 cases, the splenic artery (SA) and superior mesenteric artery (SMA) were sewn into a single trunk using the common iliac arterial bifurcation. Occasionally, the iliac Y-graft was unsuitable for vascular reconstruction due to atherosclerosis or iatrogenic injury. Therefore, the SA was anastomosed to the side of the SMA in two cases. In one case we utilized the brachiocephalic trunk bifurcation. Portal vein elongation employed an external iliac vein procured from the donor in all 35 cases. Good perfusion was achieved in all transplanted pancreata. During the early follow-up period, two venous and one arterial thromboses were noted. No negative effects of pancreatic vessel reconstruction were observed in postoperative graft function. Reconstruction of the pancreas vasculature did not affect the long-term function of the allograft while significantly increasing the available donor organ pool.

Comparison of 1-year patient and graft survival rates between preemptive and dialysed simultaneous pancreas and kidney transplant recipients.

It is well known that the main decrease in graft and recipient survival rates is observed during the first 12 months after transplantation. Improving results during this period seems to be crucial for the late outcome. The aim of this study was to compare 1-year survival rates of dialyzed and preemptive pancreas and renal graft recipients and their graft function. From November 1999 to January 2005, 42 whole simultaneous pancreas and kidney transplantations (spktx) were stratified into group I (n = 13): recipients who received a preemptive pancreas and kidney transplant versus group II (n = 29): previously dialyzed spktx recipients. The mean time of dialysis for group II was 39 +/- 16.5 months. We assessed 1-year cumulative survival rates for recipients and grafts for each group. The 1-year cumulative survival rate for preemptive graft recipients was significantly higher than that for dialyzed patients before spktx (100% vs 69%; P = .05). For groups I and II 1-year cumulative graft survival rates for kidney grafts were 100% and 89%, respectively, and for pancreatic grafts 84% and 65.5%, respectively. There was a significant improvement in the 1-year survival rate of preemptive spktx recipients compared with patients dialyzed before spktx. However, 1-year pancreas and kidney graft function did not differ significantly between the groups.