Search

We propose a functorial concurrent semantics for Petri nets extended with read and inhibitor arcs, that we call inhibitor nets. Along the lines of the seminal work by Winskel on safe (ordinary) nets, the truly concurrent semantics is given at a categorical level via a chain of coreflections leading from the category SW-IN of semi-weighted inhibitor nets to the category Dom of finitary prime algebraic domains (equivalent to the category PES of prime event structures). As an intermediate semantic model, we introduce inhibitor event structures, an event-based model able to faithfully capture the dependencies among events which arise in the presence of read and inhibitor arcs. Inhibitor event structures generalise several event structure models in the literature, like prime, asymmetric and bundle event structures. [Copyright &y& Elsevier]

Abstract: Background: Lymphorrhea is a minor complication after kidney transplantation but may develop into a lymphocele and prolong hospital stay. Treatment is conservative based on percutaneous drainage until lymphatic leakage cessation. It has been reported that octreotide has beneficial effects to treat lymphorrhea after axillary node dissection and excision of lymphatic malformations. The aim of this study was to report preliminary experience about octreotide treatment in lymphorrea after kidney transplantation. Materials and Methods: This retrospective study included 20 recipients of cadaveric kidney allografts with posttransplant lymphorrhea including 10 treated with instillation of povidone iodate solution, and the other 10 with octreotide (0.1 mg three times a day subcutaneously). We reviewed the daily amount of fluid collection, duration of lymphorrhea, complications, lymphocele formation, rejection episodes, graft outcomes, and hospital stay. Results: The average duration of lymphorrhea was 8.5 (±4.5) and 16.3 (±7.3) days for the octreotide versus the povidone groups, respectively (P = .001). No complications occurred among the octreotide group, while three lymphoceles grew among patients treated with povidone solution. No differences were observed for acute rejection episodes or renal function between the groups. No octreotide-related adverse events were noted. Conclusion: The mean length of lymphorrhea was lower with octreotide versus iodate povidone solution treatment. There was a shorter hospital stay and minor patient discomfort. In conclusion, lymphatic leakage after kidney transplantation may be successfully managed by octreotide administration. [Copyright &y& Elsevier]

Abstract: Introduction: The use of kidneys from expanded criteria donors (ECD) is an attractive strategy to enlarge the pool of organs available for transplantation. Considering the fact that ECD organs have a reduced nephron mass, they are preferentially allocated for dual-kidney transplantation (DKT). Authors have reported excellent results of DKT when pretransplant ECD organs are evaluated for histological scores. The aim of this study was to evaluate DKT donor and recipient characteristics for comparison with DKT posttransplant outcomes versus those of recipients of single-kidney transplantations from expanded criteria (edSKT) and ideal donors (idSKT). We analyzed the potential prognostic factors involved in DKT among a population derived from three transplant centers. Materials and methods: Between 2001 and 2007, DKT (n = 80) were performed based upon the ECD kidney allocation assessed by biopsy. Results: The average donor ages for the DKT, edSKT, and idSKT groups were 68.8 ± 7.8, 65.3 ± 7.2, and 40.1 ± 13.8 years, respectively (P < .001). The number of human leukocyte antigen mismatches was greater in the DKT group (3.1 ± 1.2, P < .05). Patient and graft 5-year survival rates were similar among DKT, edSKT, and idSKT recipients, namely, 97.5% versus 95.8% versus 96.9% and 93.7% versus 87.4% versus 86.9%, respectively. Mean serum creatinine values at discharge were lower in the DKT and idSKT recipients (1.5 ± 0.9 and 1.6 ± 0.7 mg/dL; P < .05) compared with the edSKT group (1.9 ± 0.7 mg/dL). Correlations between supposed prognostic factors and survival among the DKT group noted worse outcomes in reoperation cases (P < .05). Conclusion: We confirmed that DKT produced successful outcomes. An accurate surgical procedure is particularly important to try to avoid reoperations. In our experience, the use of a biopsy as an absolute criterion to allocate ECD kidneys may be too protective. [Copyright &y& Elsevier]

BACKGROUND. The living donor nephrectomy has to be safe and effective, allowing a good graft function in the recipient. In the past, donor nephrectomy was performed only by open technique; more recently this nephrectomy has also been performed by laparoscopic technique. The best technique has not been established in literature. The purpose of this study is to report the results of open and laparoscopic nephrectomy in living donors. MATERIALS AND METHODS. From January 1992 to August 2008, 37 living donor nephrectomies were performed. 23 nephrectomies were achieved by laparoscopic procedure (LDN) and 14 by open technique (ODN). The 2 groups were comparable regarding both donor and recipient characteristics. RESULTS. All laparoscopic nephrectomies were successfully performed without conversion to open procedure. No donor deaths were reported in either groups. 3 complications (13%) in the LDN group and 1 (7.1%) in the ODN group (p=0.6) were observed. Mean operative time was higher in the LDN group (p<0.036). Mean warm and cold ischemia time, resumption of oral intake and hospital stay were shorter in the LDN group (p<0.04)( p<0.03) (p<0.0001), whereas the return to normal occupational life was similar (p<0.52). We had no significant differences in the surgical complication rates, graft and patient survival. CONCLUSIONS. Our experience suggests that both procedures can be used safely and efficiently, and assure a good renal function in the recipient. Laparoscopic nephrectomy, although more difficult, provides post-operative advantages. However, laparoscopic procedure must be performed by experienced centres only to prevent serious complications in the donor. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: Acute diverticulitis with colon perforation is a serious condition in transplant recipients. The aim of this study was to analyze our experience with colon perforations among 875 renal transplant recipients between January 1986 and September 2004. Methods: Patients were analyzed by age, gender, steroid dosage, time interval from the transplantation, delay between symptoms and surgery, clinical presentation, surgical procedure, graft and patient outcomes. Results: We identified 8 patients with colon perforation. The incidence of perforation was 0.9%. Mean age at the the time of perforation was 58.5 years. Fever, abdominal pain, localized or diffuse signs of peritonitis, and leukocytosis were present in 7 patients (87.5%). Three patients (37.5%) were on steroid-free immunosuppression, whereas in 2 cases (25%) the steroid dosage was >20 mg/d. The mean interval between transplantation and perforation was 4.1 years. Two episodes (25%) occurred within 1 month following transplantation and the other 6 (75%) between 1 and 15 years. The interval between the onset of symptoms and surgery was longer than 48 hours in 1 patient (12.5%). In 5 cases (62.5%), a Hartmann procedure was performed; in 2 patients (25%), a resection with primary anastomosis was preferred. The last patient had a direct suture of the colon. Mortality rate was 12.5%. At a median follow-up of 6.1 years, 6 patients (75%) are alive with 5 functioning grafts. Conclusions: Colon perforations in renal transplant recipients remain a challenging surgical problem. An aggressive diagnostic attitude and an immediate surgical treatment may contribute to significantly decrease the incidence and the mortality of this complication. [Copyright &y& Elsevier]

Abstract: Pseudoaneurysm associated with an arterioenteric fistula is rare, but its clinical manifestations may represent a dramatic event that involves diagnostic and therapeutic problems. We report a case of an arterioduodenal fistula related to a ruptured pseudoaneurysm after simultaneous pancreas-kidney transplantation (SPK) with massive gastrointestinal hemorrhage treated by embolization of the Y graft. A 51-year-old man with type I diabetes and end-stage renal disease underwent SPK. No rejection episodes were documented; the patient was discharged with normal pancreatic and renal function. Two months later the patient was readmitted for an episode of massive lower digestive bleeding and hypotension. The Y-graft was embolized in order to obtain a prompt arrest of the bleeding. The procedure was successful and the patient progressively recovered. Once the hypovolemia was completely corrected, the graft was removed. An arterioenteric fistula between donor mesenteric artery and duodenum was confirmed. Few reports exist in the literature regarding the development of a pseudoaneurysm after pancreas transplantation. To our best knowledge only one case of pseudoaneurysm rupture into donor duodenum has been recently published. In our case angiography recognized the site of the pseudoaneurysm and its rupture into donor duodenum. Embolization of the Y-graft appeared the most rapid, simple, and safe approach to obtain the prompt arrest of the massive bleeding. Embolization of the Y-graft may represent a valid option in the presence of life-threatening hemorrhage. [Copyright &y& Elsevier]

Abstract: Background: Marginal organs not suitable for single kidney transplantation are considered for double kidney transplantation (DKT). Herein we have reviewed short and long-term outcomes of DKT over a 7-year experience. Patients and Methods: Between 2001 and 2007, 80 DKT were performed in the transplant centers of Bologna, Parma, and Modena, Italy. Recipient mean age was 61 ± 5 years. The main indications were glomerular nephropathy (n = 33) and hypertensive nephroangiosclerosis (n = 14). Mean HLA A, B, and DR mismatches were 3.1 ± 1.2. Donor mean age was 69 ± 8 years and mean creatinine clearance was 75 ± 27 mL/min. Almost all kidneys were perfused with Celsior solution. Mean cold ischemia time was 17 ± 4 hours and mean warm ischemia time was 41 ± 17 minutes. Mean biopsy score was 4.4. Immunosuppression was based on tacrolimus (n = 52) or cyclosporine (n = 26). Results: Fifty (62.5%) patients displayed good postoperative renal function. Thirty (37.5%) experienced acute tubular necrosis and required postoperative dialysis treatment; 8 acute rejections occurred. Urinary complications were 13.7% with 8/11 requiring surgical revision. There were 6 surgical reexplorations: intestinal perforation (n = 2), bleeding (n = 3), and lymphocele (n = 1). Two patients lost both grafts due to vascular and infectious complications at 7 or 58 days after transplantation. Two patients underwent intraoperative transplantectomy due to massive vascular thrombosis. Four (5%) patients underwent transplantectomy of a single graft due to vascular complications (n = 2), bleeding (n = 1), or infectious complications (n = 1). Graft and patient survivals were 95% and 100% versus 93% and 97% at 3 versus 36 months, respectively. Conclusions: DKT is a safe approach for organ shortage. The score used in this study is useful to determine whether a kidney should be refused or accepted. [Copyright &y& Elsevier]

Abstract: Introduction: The learning curve of laparoscopic donor nephrectomy (LDN) may represent a great technical challenge at centers with low volume of living donors. The number of LDNs required to overcome the learning curve is still unclear. Here we report the modality of approach to LDN at a low-volume living donor transplant center. Materials and methods: We reviewed the records of two groups of donors operated by two different surgeons between January 2002 and October 2005. We compared donor hospital stay, operative time, presence of multiple renal arteries, blood loss, operative details, and complications. Results: The first six operations (group A) were performed by a well-trained laparoscopic surgeon (A.P.) with a consolidated experience in the LDN procedure, attended by our training surgeon (R.D.V.) who conducted the other six cases (group B). No conversion to an open procedure was necessary and there were no major minor complications. Mean operative time was 267.5 (±55.9) minutes in group A and 300 (±43.4) minutes in group B (P = .28). Mean warm ischemia time was 125 (±61.6) seconds in group A and 189.2 (±18.6) seconds in group B (P = .035). Mean hospital stay was 5.3 days in group A and 5.6 days in group B. Conclusions: LDN can be performed safely and efficiently in transplant centers with initial experience. A collaborative approach to this difficult procedure with a surgeon skilled in donor nephrectomy minimizes the risk to the donor and reduces the learning curve. [Copyright &y& Elsevier]

Abstract: Percutaneous renal artery embolization has been introduced as an alternative to nephrectomy for patients with a nonfunctioning allograft and Graft Intolerance Syndrome. The symptoms resulting from this syndrome include fever, local pain, hypertension, and hematuria. From April 2003 to October 2003, 5 patients were treated with this technique. The intraparenchymal renal arteries were embolized by injection of calibrated tris-acryl gelatin microspheres of increasing size (from 100–330 to 700–900 μm) and completed with the insertion of 5-mm–8-mm steel coils in the renal artery. The procedure was well tolerated in all cases; no major complications occurred. In 3 patients, the symptoms disappeared immediately. In 1 patient, it was necessary to perform a second embolization due to collateral circulation developing from a lumbar artery; this further procedure resolved the symptoms. In the last case, the patient underwent nephrectomy because of septic fever. In conclusion, patients with this syndrome refractory to medical treatment may be treated by the effective and minimally invasive procedures of percutaneous allograft artery embolization with no significant short-term or late complications. [Copyright &y& Elsevier]

Abstract: Aim: The aim of present study was to assess the effect of Celsior as compared with University of Wisconsin (UW) solution on immediate and long-term function of kidney transplants harvested from elderly donors. Methods: A prospective multicenter randomized study was designed to evaluate the efficacy of Celsior versus UW solution for the clinical preservation of the kidney. Fifty renal transplants were performed from donors over 60 years old. Twenty-five kidneys were stored in Celsior and 25 in UW solution. The groups were comparable with regard to donor and recipient characteristics. Renal function outcomes were compared by evaluating delayed graft function rates, daily urinary output, as well as the evolution of mean serum creatinine at 1, 3, 5, 7, and 15 days. Results: The warm ischemia time was 42.4 ± 11 minutes among Celsior vs 46.9 ± 17.9 minutes in the UW cohort (P = NS). The cold ischemia time was 18 ± 4.5 hours in Celsior and 19 ± 6.5 hours in UW (P = NS). Delayed graft function occurred in 48% of the Celsior group and in 52% of the UW group (P = NS). Mean serum creatinine levels and mean daily urinary output were also similar. One- and 5-year graft survivals of kidneys preserved with Celsior were 91.8% and 79.3% compared with 96% and 87.4% for UW without any significant statistical difference. Conclusions: Our data show that the preservation of kidneys from elderly donors in Celsior solution is equivalent to that of UW solution. [Copyright &y& Elsevier]

Abstract: Introduction: We reviewed our clinical experience to assess the role of cholecystectomy transplant candidates pre- and posttransplantation. Methods: Between April 1986 and December 2003, 57 (6.8%) candidates among 839 kidney transplants were found during routine pretransplant screening to show gallstones. Results: Thirty nine (68.4%) symptomatic patients underwent cholecystectomy before transplantation. Among 18 (31.6%) asymptomatic patients monitored after transplantation, the 7 (39%) who developed biliary tract symptoms underwent laparoscopy or minilaparocholecystectomy without postoperative morbity, mortality, or graft loss. Conclusions: Symptomatic gallstones have to be treated using the laparoscopic cholecystectomy or minilaparotomy technique. In asymptomatic cholelithiasis prophylactic cholecystectomy is only reserved for patients with biliary “intrinsic” risk factors. An early diagnosis and prompt surgical treatment yields good results. [Copyright &y& Elsevier]

A short right renal vein may be associated with technical problems in renal transplantation. For this reason, a vena caval extension may be useful to improve exposure of the anastomosis and graft placement. This report evaluates the safety and the effectiveness of renal vein extension, which was routinely performed in right renal transplantation. From April 1986 to December 2002, we performed 371 right kidney transplantations with 252 using the standard technique (group A) and 119 using the renal vein extension (group B). No statistical differences were found between the 2 groups in terms of renal vein thrombosis incidence, delayed graft function, morbidity, and graft loss. Indeed, mean warm ischemia time was reduced in the venoplasty group. In conclusion, renal vein extension is an easy, safe technique that reduces warm ischemia time. We suggest more extensive use of this procedure in right kidney transplantation. [Copyright &y& Elsevier]