Artificial Neural Network Structure Optimisation in the Pareto Approach on the Example of Stress Prediction in the Disk-Drum Structure of an Axial Compressor.

The article presents the process of selecting and optimising artificial neural networks based on the example of determining the stress distribution in a disk-drum structure compressor stage of an aircraft turbine engine. The presented algorithm allows the determination of von Mises stress values which can be part of the penalty function for further mass optimization of the structure. A method of a parametric model description of a compressor stage is presented in order to prepare a reduced stress distribution for training artificial neural networks. A comparative analysis of selected neural network training algorithms combined with the optimisation of their structure is presented. A genetic algorithm was used to determine the optimal number of hidden layers and neurons in a layer. The objective function was to minimise the absolute value of the relative error and standard deviation of stresses determined by FEM and artificial neural networks. The results are presented in the form of the Pareto front due to the stochastic optimisation process.

Long-term outcome of renal transplantation: a 10-year follow-up of 765 recipients.

INTRODUCTION: Renal transplantation is a treatment of choice for patients with end­stage renal disease. The main goal of transplant care is to achieve the best long­term patient survival (PS) and graft survival (GS). OBJECTIVES: We aimed to assess the impact of various immunosuppression (IS) protocols on PS and GS following renal transplantation. PATIENTS AND METHODS: This was a retrospective single­center cohort study including a total of 765 consecutive adult renal transplant recipients (RTRs) who underwent transplantation between 1998 and 2003. The primary endpoints included PS and GS. The secondary endpoints were graft function determined by estimated glomerular filtration rate and hospitalization length per patient per year. RESULTS: Ten­year PS and GS rates were 88.6% and 78.7%, respectively. The intent­to­treat (ITT) group received IS that was later changed, whereas in the group on randomized therapy (ORT), the same IS protocol was maintained during follow­up. The ITT group had significantly better PS and GS than the ORT group. In the ITT group, patients treated with a combination of tacrolimus (TAC) and azathioprine (AZA), cyclosporine (CSA) and AZA, or CSA and mycophenolic acid metabolites (MPAs) had significantly better PS than those treated with TAC and MPA. The ORT group receiving AZA in any combination also had significantly better PS than MPA­treated individuals. CONCLUSIONS: The effect of IS protocols on long­term outcomes varies depending on patient subpopulations. Immunosuppressive therapy solves rejection­related problems but does not address the increasing mortality of RTRs due to cardiovascular diseases, malignancies, or infections. Therefore, treatment recommendations should be individualized and posttransplant care, provided mainly by internists, should be carefully structured to improve long­term outcomes of renal transplantation.

Successful transplantation of kidneys from deceased donors with terminal acute kidney injury.

BACKGROUND: There are many doubts with regards to accepting deceased kidneys with acute kidney injury (AKI) for transplantation. PURPOSE: The aim of this study was to present the 5-years outcome of kidney transplantation cases where deceased donors developed AKI before organ procurement. METHODS: Two hundred twenty-six deceased renal transplants were analyzed. Data regarding donors and recipients were collected. Terminal AKI was defined as terminal serum creatinine concentration higher than 1.99 mg/dL and 66 such cases were diagnosed. All kidney transplant recipients were followed for 60 months. RESULTS: AKI group presented more episodes of delayed graft function (DGF) compared to the non-AKI group (56% vs 35%, p < .05). No differences were observed between the groups in the rate of acute rejection episodes, kidney function as well as patient and graft survival. CONCLUSIONS: Transplants with AKI present more often DGF and comparable graft survival to transplants without AKI. Kidneys with AKI can be a valuable source of organs provided attentive selection and appropriate care of deceased donors.

Building Kidney Exchange Programmes in Europe-An Overview of Exchange Practice and Activities.

BACKGROUND: Considerable differences exist among the living donor Kidney Exchange Programmes (KEPs) that are in use and being built in Europe, contributing to a variation in the number of living donor transplants (Newsletter Transplant; International figures on donation and transplantation 2016). Efforts of European KEPs to exchange (best) practices and share approaches to address challenges have, however, been limited. METHODS: Experts from 23 European countries, collaborating on the European Network for Collaboration on Kidney Exchange Programmes Cooperation on Science and Technology Action, developed a questionnaire to collect detailed information on the functioning of all existing KEPs in Europe, as well as their opportunities and challenges. Following a comparative analysis, results were synthesized and interpreted by the same experts. RESULTS: The practices, opportunities and challenges reported by 17 European countries reveal that some of the 10 operating programs are mature, whereas others are in earlier stages of development. Over 1300 transplants were performed through existing KEPs up to the end of 2016, providing approximately 8% of their countries' living kidney donations in 2015. All countries report challenges to either initiating KEPs or increasing volumes. Some challenges are shared, whereas others differ because of differences in context (eg, country size, effectiveness of deceased donor program) and ethical and legal considerations (eg, regarding living donation as such, nonrelated donors, and altruistic donation). Transnational initiatives have started in Central Europe, Scandinavia, and Southern Europe. CONCLUSIONS: Exchange of best practices and shared advancement of national programs to address existing challenges, aided by transnational exchanges, may substantially improve access to the most (cost) effective treatment for the increasing number of patients suffering from kidney disease.

Determining eligibility for and preparation to kidney transplantation of a patient with Lynch syndrome--a case report and literature review.

BACKGROUND: Lynch syndrome (HNPCC, hereditary non-polyposis colorectal cancer) is a syndrome of predisposition to cancer inherited in an autosomal dominant fashion. A person with Lynch syndrome has a considerably increased risk of colorectal cancer in comparison with the general population. CASE REPORT: We present a case of a 24-year-old man with Lynch syndrome (carrying an MLH1 gene mutation) who had colorectal adenocarcinoma diagnosed at 16 years of age. During this time, he had a colectomy performed and chemotherapy was administered (5-FU, CDDP, Leucovorin). Due to hepatic metastases, a decision was made to change chemotherapy to IF with ADM, as a result of which complete remission was obtained. However, kidney failure developed. Its cause was not fully elucidated. The patient was treated by hemodialyses. After six years of complete remission of cancer, kidney transplantation started to be considered. Before the patient was found eligible for transplantation, extended diagnostic tests were performed: whole body PET scan, tumour marker tests and intestinal endoscopy, which did not reveal any abnormalities. The patient had a family donor (mother) who had no contraindications to kidney donation. Kidney transplantation was performed on 15/10/2012. Induction with basiliximab was used, along with steroids, tacrolimus, and mycophenolate mofetil was also administered. Three months after the procedure CNI/mTOR conversion was performed. The maintenance treatment includes prednisone, everolimus and mycophenolate mofetil. One year after transplantation, renal function is normal. The patient is subjected to close oncological surveillance. CONCLUSIONS: The risk of recurrence or new development of cancer related to immunosuppressive treatment should be considered on a case-by-case basis. In patients with a history or high risk of cancer, immunosuppression protocols based on the m-TOR pathway inhibitors should be used, if possible. Oncological surveillance and early detection of new cancer lesions are also important.

One-year results of a prospective, randomized trial comparing two machine perfusion devices used for kidney preservation.

Studies have shown beneficial effects of machine perfusion (MP) on early kidney function and long-term graft survival. The aim of this study was to investigate whether the type of perfusion device could affect outcome of transplantation of deceased donor kidneys. A total of 50 kidneys retrieved from 25 donors were randomized to machine perfusion using a flow-driven (FD) device (RM3; Waters Medical Inc) or a pressure-driven (PD) device (LifePort; Organ Recovery Systems), 24 of these kidneys (n = 12 pairs; 48%) were procured from expanded criteria donors (ECD). The primary endpoints were kidney function after transplantation defined using the incidence of delayed graft function (DGF), the number of hemodialysis sessions required, graft function at 12 months, and analyses of biopsy. DGF was similar in both groups (32%; 8/25). Patients with DGF in the FD group required a mean of 4.66 hemodialysis sessions versus 2.65 in the PD group (P = 0.005). Overall, 1-year graft survival was 80% (20/25) vs. 96% (24/25) in the FD and PD groups. One-year graft survival of ECD kidneys was 66% (8/12) in the FD group versus 92% (11/12) in the PD group. Interstitial fibrosis and tubular atrophy were significantly more common in the FD group - 45% (5/11) vs. 0% (0/9) (P = 0.03) in PD group. There were no differences in creatinine levels between the groups. Machine perfusion using a pressure-driven device generating lower pulse stress is superior to a flow-driven device with higher pulse stress for preserving kidney function.

[Current trends in the treatment of incisional hernia in patients after kidney transplantation]. / Aktualne trendy w leczeniu przepukliny pooperacyjnej po przeszczepieniu nerki.

The incidence of incisional hernia following abdominal surgery varies between 2 and 13%, the rate of incisional hernia after renal transplantation varies between 1.1 and 3.8%. There are no evidence based guidelines regarding the treatment of incisional hernias in renal transplant recipients. The aim of this study was to compare results of surgical repair of incisional hernia in patients after renal transplantation depending on the treatment method. A Pubmed was searched for articles related to the treatment of patients with incisional hernia after renal transplantation. Finally five articles were used for review. The analyzed papers report a total of 5606 patients in a time period between 1965-2004. Hernia mesh repairs were similar - primary approximation of the fascial borders and polypropylene mesh reinforcement, mainly by on lay technique or by suturing the mesh to fascial edges. Hernia repairs without mesh were diverse: simple closure, component separation technique, tensor fascia late grafts, split thickness skin grafting. Although all authors are concerned about prosthetic mesh use for hernia repair in transplant patients, four of them advise this method. Surprisingly, the incidence of incisional hernia in transplant recipients (1.83%) is no higher than in normal population (2-13%). Hernia recurrence in the analyzed group was 2% for prosthetic mesh repair, and 25% for no mesh repair. Prosthetic mesh repair of incisional hernias after kidney transplantation is a safe technique and starting to displace other methods of treatment.

TransEndoscopic Gastric SubMucosa Islet Transplantation (eGSM-ITx) in pigs with streptozotocine induced diabetes - technical aspects of the procedure - preliminary report.

BACKGROUND: Islets and pancreas transplantation have become standard treatments of patients with diabetic complications. However pancreas transplantation is associated with high incidence of complications and the long-term results of islet transplantation are still unsatisfactory. Loss of pancreatic islets grafts is caused not only by immunological reactions but also due to the site of grafting and IBMIR. Gastric submucosal space could be an alternative site for transplantation. The aim of this study was to assess the possibility of endoscopic islets transplantation into the gastric submucosa-its efficacy and potential complications.
MATERIAL/METHOD: 20 Landrace pigs weighing 19-24 kg were obtained for the study. Seven animals were controls (C-group) and 13 formed the transplantation group (TX group). In both groups diabetes was induced by streptozotocine (stz) infusion at a dose of 200 mg/kg. At 7 days post stz infusion pigs of both groups underwent endoscopy-in group C to assess the feasibility of gastroscopic examination under general anaesthesia in pigs with diabetes and to study the influence of basiliximab infusion on pigs, in the Tx-group to perform endoscopic submucosal islet transplantation (eGSM-ITx). Immunosuppression consisted of tacrolimus 0.2 mg/kg and sirolimus 6 mg/m(2). At 7 days post transplantation, control gastroscopy was performed to assess the gastric mucosa and to obtain biopsies for histopathology. 10 to 30 days after eGSM-ITx, magnetic resonance (MRI) scan was performed. Stomach and pancreas were obtained at autopsy for histopathology. Glycemia was assessed twice daily during the experiment. For 10 days after diabetes induction (up to three days after eGSM-ITx) in both groups, insulin was given to reach glycemia between 150-200 mg/dl, after that period insulin was given only when glycemia exceeded 600 mg/dl.
RESULTS: There were no differences in insulin requirement and glycemia up to the day of eGSM-ITx between the groups. Tx-group animals received a mean of 6000+/-3170 IEQ/kg. Tx-group animals had a significantly lower insulin requirement and significantly lower mean glycemia since the first day post transplantation. C-group animals all required insulin once daily to keep glycemia below 600 mg/dl. There were no signs of perforation, ulceration or bleeding after eGSM-ITx on gastroscopy and histopathological examination. MRI scans revealed unspecific thickening of gastric wall at sites of islet deposition.
CONCLUSIONS: Transendoscopic islets transplantation into gastric submucosa is feasible and a safe procedure in an experimental animal setting. Its potential for clinical application in human subjects needs further studies.