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Abstract: To realize the basic units of fractional order controllers, it is necessary to approximate irrational differintegrators. Many methods deal with analog approximation. But not many results exist for discrete approximation. In this case, approximations are most times poor in some frequency range, or the quality of the approximation is good in a narrow frequency interval. This paper proposes an indirect discretization method that takes advantage from the particle swarm optimization (PSO) to approximate fractional order operators. The method employs an heuristic procedure to optimize the interlacing of zero–pole pairs on the real axis. Then, a discretization rule is applied to obtain the discrete approximation. Simulation results show that the frequency response obtained by PSO improves the approximation offered by other efficient and recent indirect discretization techniques. [Copyright &y& Elsevier]

Abstract: We retrospectively studied the incidence of urological complications in a consecutive series of 590 patients (group B) who received a kidney transplant (KT) with a ureteral stent from January 1994 to December 2002. The ureteral stent was sewn to the bladder catheter during the surgical procedure and left in situ for a mean time of 10 days (range 8 to 12 days). The results were compared to a consecutive series of 414 patients who received a KT from March 1986 to December 1993 without a ureteral stent (group A). The two groups were comparable in terms of donor and recipient gender, ischemia time, delayed graft function, and chronic rejection incidence, but differed in mean donor age (44.1 vs 36.0 years), mean recipient age (45.4 vs 39.1 years), living/cadaveric donor rate (19.8% vs 11.9%), arterial lesions and bench reconstruction rate (11.1 vs 3.5%), as well as acute rejection episodes (11.7% vs 29.2%). Complications were seen in nine patients in group B (1.5%) and 17 patients in group A (4.1%) (P < .0001). Urinary leaks presented in two patients in group B (0.3%) and 11 patients in Group A (2.6%; P < .0001), while stenosis was present in six patients in group B (1.5%) and 7 in group A (1.2%) (P = NS). Urological complications such as urinary tract infection and macroscopic hematuria were similar in both groups. Time to presentation of a leak was within 2 weeks from KT in 10 patients (92.3%), while stenosis presented early in four patients (one in group B and four in group A). Of the stenoses, 69.3% presented late (beyond 12 weeks) in five patients in group B and three in Group A. In conclusion, our data suggest that routine use of double pigtail ureteral stent significantly decreased the incidence of leaks and early stenoses, but it did not modify late stenosis incidence. In the last decade, risk factors for urological complications have been increasing over time, namely, older donors and older recipients, living donation, length of dialysis, and the use of grafts with arterial lesions. Therefore we believe that a ureteral stent should be routinely considered to afford the advantage to protect the urinary anastomosis in the early postoperative period when the incidence of complications is highest, without the need of cystoscopy for its removal. [Copyright &y& Elsevier]

Abstract: Perioperative donor morbidity, a barrier to living organ donation, may be mitigated by the laparoscopic approach. From September 2002 to September 2004, 15 living donors, of ages ranging from 36 to 59 years, underwent laparoscopic nephrectomy. We used a hand-assisted device to increase the safety of the procedure. The average operating time was 200 minutes. The average blood loss was about 100 mL. The patients resumed oral intake and started walking within 1 day. The average postoperative hospital stay was 6 days. Although laparoscopic operating times were longer than those for traditional surgery, we showed benefits to the laparoscopic donor to be less postoperative pain, better cosmesis, shorter recovery time, and faster return to normal activities. We therefore consider laparoscopic nephrectomy a good alternative to traditional surgery for selected patients. Despite a lack of strong evidence, such as large prospective randomized studies, laparoscopic donor nephrectomy is likely to become the gold standard for donor nephrectomy in the near future. [Copyright &y& Elsevier]

Abstract: Surgical complications are the leading cause of pancreatic graft loss among diabetic patients who undergo pancreas transplantation alone (PTA), or combined with kidney transplantations (PK) or after kidney transplantations (PAK). Therapeutic effects on secondary complications of diabetes justify pancreas retransplantation (re-PT) when the first graft is lost. However, the appropriate timing for retransplant and related problems is not known. We present our initial experience on re-PT performed on seven diabetic patients who lost their first pancreas grafts (PK) due to surgical complications (venous thrombosis in five and enteric fistula in two). Five re-PT were performed a few days after the first PT without a second course of induction therapy, while two patients received re-PT some months later with reinduction therapy. In the early re-PT group, one patient died some hours after the second surgical procedure due to pulmonary embolism, while four patients lost their second grafts due to accelerated rejection within 2 years from re-PT. In the late re-PT group, both patients have good graft function without signs of rejection. Our initial experience showed discouraging results in the group of early re-PT, due to accelerated rejection episodes leading to a high incidence of graft loss. Late re-PT accompanied by reinduction therapy seemed to have better results. [Copyright &y& Elsevier]

Abstract: We examined surgical complications among a group of diabetic type 1 patients (IDDM) with end-stage renal disease (ESRD) who had undergone pancreas-kidney transplantations (PK). Between October 1993 and August 2004, 70 SPK were performed using bladder (n = 14) or enteric (n = 56) drainage. Donors were selected according to standard criteria (mean age, 27.6 years; range, 17–49). All patients received cyclosporine-based immunosuppression. All pancreata functioned immediately, whereas 2 patients needed postoperative dialysis. Four patients (5.7%) lost their pancreatic graft due to vascular thrombosis; both patients underwent urgent allograft pancreaectomy and pancreas retransplantation (re-PT). One of them (1.4%) experienced a venous thrombosis and died due to a pulmonary embolism at 12 hours after re-PT. The other 3 patients had uneventful postoperative courses and were discharged with good pancreatic and renal function. Three patients in the bladder group (21.4%) had an anastomotic leak, which resolved with a bladder catheter. Four patients in the enteric group (7.1%) who experienced an anastomotic leak needed a second surgical procedure but in 3 of them allograft pancreatectomy was necessary. Relaparotomy was required in the other 3 patients due to hemorrhage (1 patient) or occlusion (2 patients). Acute rejection episodes, which occurred in 16 patients (22.8%), were treated with steroid boluses. With a mean follow-up of 72 months (range, 3–129), 2 patients have died at 8 and at 36 months, respectively, after SPK due to acute myocardial infarction (2.9%). Chronic rejection was the leading cause of pancreatic failure in 5 patients (7.1%) and of renal failure in 2 patients (2.8%). Patient, kidney, and pancreas survival rates were 95.8%, 92.9%, and 81.5%, respectively. Surgical complications were the leading cause of pancreatic allograft loss in IDDM and ESRD patients submitted to SPK. [Copyright &y& Elsevier]

Abstract: Living donation in the field of renal transplantation has increased over time as well as the use of laparoscopic nephrectomy. We present a 15-year experience on 162 living donors (105 women, 57 men; mean age, 46.7 years; range, 31–74 years) who underwent nephrectomy using different surgical approaches as open lombotomic nephrectomy (OLN), open transperitoneal nephrectomy (OTN), and laparoscopic hand-assisted nephrectomy (LHAN). We collected data on residual donor and recipient renal function, as well as early versus late medical and surgical complications. With a mean follow-up of about 8 years, we observed normal residual renal function in all donors and similar results of early and late graft function independent of the surgical procedure. Long-term incidence of hypertension and noninsulin-dependent diabetes in living donors was similar to the general population. OLN and OTN donors showed higher incidences of early and late complications, readmissions, and reoperations than LHAN donors. Our results confirmed that living donor nephrectomy is a safe procedure without serious side effects in terms of renal function and long-term quality of life. LHAN should be the preferred technique because of a lower incidence of early and late complications. [Copyright &y& Elsevier]