Longitudinal evaluation of mycophenolic acid pharmacokinetics in pediatric kidney transplant recipients. The role of post-transplant clinical and therapeutic variables.

This longitudinal study assessed the influence of post-transplant clinical and therapeutic variables in 50 kidney transplant recipients aged 2-19 yr receiving a triple immunosuppressive regimen consisting of cyclosporine microemulsion (CsA), steroids and MMF (300-400 mg/m(2) body surface area twice daily), the full pharmacokinetic profile (10 points) of which was investigated on post-transplant days 6, 30, 180 and 360. Total plasma MPA was measured by Enzyme Multiplied Immunoassay Technique. CsA therapeutic drug monitoring (TDM) was performed via C2 blood monitoring, while MPA TDM via C0. MPA Cmax, tmax, AUC0-12 and AUC0-4 pharmacokinetic profile changed significantly during the first post-transplant year. C0 was a poor predictor of the total MPA exposure [as measured by the area under the concentration-time curve AUC)], while a truncated AUC was a good surrogate of the 12-h profile (r = 0.91; p < 0.001) Graft function and cyclosporine therapy influenced MPA pharmacokinetics, as shown by the univariate and multivariate analyses. We conclude that because after transplantation MPA exposure varied over time, a strict TDM is advisable in the pediatric population.

Prophylaxis after first febrile urinary tract infection in children? A multicenter, randomized, controlled, noninferiority trial.

OBJECTIVES: Febrile urinary tract infections are common in children and associated with the risk for renal scarring and long-term complications. Antimicrobial prophylaxis has been used to reduce the risk for recurrence. We performed a study to determine whether no prophylaxis is similar to antimicrobial prophylaxis for 12 months in reducing the recurrence of febrile urinary tract infections in children after a first febrile urinary tract infection. METHODS: The study was a controlled, randomized, open-label, 2-armed, noninferiority trial comparing no prophylaxis with prophylaxis (co-trimoxazole 15 mg/kg per day or co-amoxiclav 15 mg/kg per day) for 12 months. A total of 338 children who were aged 2 months to <7 years and had a first episode of febrile urinary tract infection were enrolled: 309 with a confirmed pyelonephritis on a technetium 99m dimercaptosuccinic acid scan with or without reflux and 27 with a clinical pyelonephritis and reflux. The primary end point was recurrence rate of febrile urinary tract infections during 12 months. Secondary end point was the rate of renal scarring produced by recurrent urinary tract infections on technetium 99m dimercaptosuccinic acid scan after 12 months. RESULTS: Intention-to-treat analysis showed no significant differences in the primary outcome between no prophylaxis and prophylaxis: 12 (9.45%) of 127 vs 15 (7.11%) of 211. In the subgroup of children with reflux, the recurrence of febrile urinary tract infections was 9 (19.6%) of 46 on no prophylaxis and 10 (12.1%) of 82 on prophylaxis. No significant difference was found in the secondary outcome: 2 (1.9%) of 108 on no prophylaxis versus 2 (1.1%) of 187 on prophylaxis. Bivariate analysis and Cox proportional hazard model showed that grade III reflux was a risk factor for recurrent febrile urinary tract infections. Whereas increasing age was protective, use of no prophylaxis was not a risk factor. CONCLUSIONS: For children with or without primary nonsevere reflux, prophylaxis does not reduce the rate of recurrent febrile urinary tract infections after the first episode.

Antibiotic treatment for pyelonephritis in children: multicentre randomised controlled non-inferiority trial.

OBJECTIVE: To compare the efficacy of oral antibiotic treatment alone with treatment started parenterally and completed orally in children with a first episode of acute pyelonephritis. DESIGN: Multicentre, randomised controlled, open labelled, parallel group, non-inferiority trial. SETTING: 28 paediatric units in north east Italy. PARTICIPANTS: 502 children aged 1 month to <7 years with clinical pyelonephritis. INTERVENTION: Oral co-amoxiclav (50 mg/kg/day in three doses for 10 days) or parenteral ceftriaxone (50 mg/kg/day in a single parenteral dose) for three days, followed by oral co-amoxiclav (50 mg/kg/day in three divided doses for seven days). Main outcomes measures Primary outcome was the rate of renal scarring. Secondary measures of efficacy were time to defervescence (<37 degrees C), reduction in inflammatory indices, and percentage with sterile urine after 72 hours. An exploratory subgroup analysis was conducted in the children in whom pyelonephritis was confirmed by dimercaptosuccinic acid (DMSA) scintigraphy within 10 days after study entry. RESULTS: Intention to treat analysis showed no significant differences between oral (n=244) and parenteral (n=258) treatment, both in the primary outcome (scarring scintigraphy at 12 months 27/197 (13.7%) v 36/203 (17.7%), difference in risk -4%, 95% confidence interval -11.1% to 3.1%) and secondary outcomes (time to defervescence 36.9 hours (SD 19.7) v 34.3 hours (SD 20), mean difference 2.6 (-0.9 to 6.0); white cell count 9.8x10(9)/l (SD 3.5) v 9.5x10(9)/l (SD 3.1), mean difference 0.3 (-0.3 to 0.9); percentage with sterile urine 185/186 v 203/204, risk difference -0.05% (-1.5% to 1.4%)). Similar results were found in the subgroup of 278 children with confirmed acute pyelonephritis on scintigraphy at study entry. CONCLUSIONS: Treatment with oral antibiotics is as effective as parenteral then oral treatment in the management of the first episode of clinical pyelonephritis in children. TRIAL REGISTRATION: Clinical Trials NCT00161330 [ClinicalTrials.gov].

Interleukin-8 and CXCR1 receptor functional polymorphisms and susceptibility to acute pyelonephritis.

PURPOSE: We performed a case-control study in children diagnosed by the first episode of upper urinary tract infection with or without vesicoureteral reflux to evaluate the association of functional polymorphism of interleukin-8 (-251A>T and +2767A>G), and its receptor CXCR1 (+2607G>C). MATERIALS AND METHODS: Genomic DNA was obtained from 265 children with a clinical and laboratory diagnosis of urinary tract infection who were recruited in northeast Italy. The children were subdivided as 173 who were dimercapto-succinic acid scan positive with positive static renal scintigraphy in acute conditions, consistent with the diagnosis of acute pyelonephritis, and 92 who were dimercapto-succinic acid scan negative. Genetic analysis for the same polymorphisms was also extended to a control population of 106 umbilical cord DNA samples. RESULTS: Statistical analysis of genotype data showed that 1) the tested populations were in Hardy-Weinberg equilibrium, 2) there were significant differences between the dimercapto-succinic acid scan positive and negative groups (p=0.049), and the dimercapto-succinic acid scan positive group vs controls (p=0.032) in terms of interleukin-8 -251A>T polymorphism frequency, 3) there was also a significant difference in the distribution of IL-8 -251A>T and +2767A>G polymorphisms between dimercapto-succinic acid scan positive and negative children in the subgroup without vesicoureteral reflux (p=0.03 and 0.02, respectively) and 4) no significant differences were found in the frequency of the distribution of CXCR1 +2607G>C polymorphism in all groups. CONCLUSIONS: These data suggest that the gene for the proinflammatory chemokine interleukin-8 is involved in susceptibility to acute pyelonephritis during upper urinary tract infection in children with or without vesicoureteral reflux.

Cadaver kidney transplantation and vascular anomalies: a pediatric experience.

BACKGROUND: The incidence of donor kidneys with vascular anomalies ranges from 18% to 30%; such kidneys are usually at increased risk of vascular and urological complications. The aim of this study was to determine whether the use of cadaver kidneys with vascular anomalies would adversely affect posttransplant graft and patient outcome. METHODS: From October 1987 to January 2004, 241 patients underwent kidney transplantation in our pediatric surgery department. Vascular anomalies were noted in 77/241 grafts (31.9%); 50 (64.9%) had multiple renal arteries and 22 (28.5%) venous anomalies. Patients were divided into three groups: Group A (1 renal artery and vein, 1 arterial and venous anastomosis [n = 161]), Group B (> 1 renal artery or vein, 1 arterial and venous anastomosis [n = 33]), and Group C (> 1 renal artery or vein, > 1 arterial and venous anastomosis [n = 47]). We compared the three groups for: patient and graft survival, incidence of posttransplant acute tubular necrosis, vascular and urological complications, postoperative mean creatinine levels, and posttransplantation hypertension. RESULTS: We found no significant differences among the three groups regarding episodes of acute rejection or acute tubular necrosis. Creatinine levels reached normal levels within 30 days in all the groups without any significant differences. Furthermore, patient and graft survival were excellent (100% and 97%). CONCLUSIONS: The presence of vascular anomalies and their multiple or complex repair does not represent a theoretical disadvantage even in pediatric patients. In order to maximize the quantity and quality of donor kidneys especially in pediatric population, kidneys with vascular anomalies may be implanted with very little risk.

Oxidative stress and post-transplant hypertension in pediatric kidney-transplanted patients.

OBJECTIVE: To test the hypothesis that oxidative stress signaling contributes to post-transplant endothelial dysfunction and hypertension in pediatric post-transplant hypertension. STUDY DESIGN: This study evaluated in 16 pediatric renal transplant patients, divided in two groups based on the presence of post-transplant hypertension, the oxidative stress status measuring the gene expression (reverse transcription-polymerase chain reaction) of two major oxidative stress-related proteins, p22(phox) and heme oxygenase-1 (HO-1). Total plasma antioxidant power (ELISA) was also evaluated. RESULTS: Mononuclear cell p22(phox) gene expression was higher in hypertensive patients compared with the normotensive group (0.91 +/- 0.06 vs 0.79 +/- 0.08 densitometric units, P < .02), whereas HO-1 RNA production and total plasma antioxidant power were higher in the normotensive group (0.38 +/- 0.04 vs 0.20 +/- 0.11 d.u., P < .006, and 1189.35 +/- 145.75 vs 772.71 +/- 196.03 micromol/L, P < .01, respectively). CONCLUSIONS: Oxidative stress is associated with post-transplant hypertension in hypertensive pediatric kidney-transplant patients, who therefore are at risk of oxidative stress-induced organ damage. They might benefit from treatments addressing not only hypertension but also oxidant-related complications.

The pharmacokinetics and immunosuppressive response of tacrolimus in paediatric renal transplant recipients.

The aims of our trial were to study the pharmacokinetics of tacrolimus in paediatric kidney transplant recipients. The study comprised 25 patients (median age 13 years, range 2-20 years) followed for 12 months; five pharmacokinetics profiles (within the first and second week and after 1 month, 6 months and 12 months) were obtained. Patients were divided into two groups: six children<6 years old and 19 older children. Tacrolimus was given at an initial dose of 0.15 mg/kg twice a day. Blood samples were drawn before and 1 h, 2 h, 3 h, 4 h, 6 h, 9 h and 12 h after drug administration. Patient and kidney survival rates were 100% at 1 year. At 6 months and 12 months creatinine clearance was 68.5+/-16.3 ml/min per 1.73 m2 and 64.0+/-15.2 ml/min per 1.73 m2 body surface area, respectively. Tacrolimus trough levels were 7.8+/-1.9 ng/ml and 7.3+/-2.5 ng/ml. The area under the concentration-time curve for 0 h to 12 h (AUC0-12) normalised to a dose of 0.15 mg/kg, increased with time from the kidney transplantation and stabilised after the 6th month post-transplantation. During the first month after transplantation the normalised tacrolimus concentration-time profiles were significantly greater in the older children (P<0.05); the actual doses were significantly greater in the younger children (P<0.05). In conclusion, initial doses of 0.15 mg/kg twice a day orally are safe and guarantee a satisfactory degree of immunosuppression, with our therapeutic regimen. Children<6 years old need to start with a 50% higher tacrolimus dose to achieve the same pharmacokinetic and immunosuppressive results.

A prospective multicentre study of the nutritional status in children on chronic peritoneal dialysis.

The anthropometry-bioimpedance analysis-nutrition (ABN) score is a recently proposed objective method of assessing malnutrition in children on chronic peritoneal dialysis (CPD) that uses nine parameters based on anthropometry, skinfold thickness and bioimpedance analysis. The aim of this prospective, cross-sectional study was to apply it to children treated with CPD in seven Italian paediatric nephrology centres, with a score of < 10.33 (the 3rd percentile in a population of 264 healthy children) classifying the children as malnourished. The other considered parameters were age, age at the start of dialysis and duration of dialysis; serum haemoglobin, urea, creatinine, total protein, albumin, transferrin, bicarbonate and C-reactive protein; residual urine output; urinary and peritoneal creatinine clearance; and daily protein and energy intake. The study enrolled 43 patients (mean age 10.2 +/- 4.2 years), 21 of whom (48.8%) had an ABN score of < 10.33: 15 with mild, five with moderate, and one with severe malnutrition. The malnourished patients started CPD at a younger age (P < 0.05) and had a longer duration of dialysis (P < 0.01), and a significant worsening in nutritional status was observed in those treated for more than 12 months of dialysis; they also had significantly lower serum albumin, creatinine and haemoglobin levels. In conclusion, protein-calorie malnutrition is common in children receiving CPD. A younger age at the start of dialysis and a longer duration of treatment are clear risk factors, and counterbalance the long-term viability of CPD in paediatric age.

Kidney transplantation into bladder augmentation or urinary diversion: long-term results.

BACKGROUND: We report on a single-institutional experience with renal transplantation in patients with severe lower urinary tract dysfunction (LUTD) who underwent bladder augmentation or urinary diversion, and assess the long-term results. METHODS: From September 1987 to January 2005, 255 patients (161 male and 94 female), 7 months to 39 years old of age (median age at time of transplantation 14 years), received 271 kidney transplants. Etiology of end-stage renal disease was LUTD in 83 cases. Among these patients, 24 had undergone bladder augmentation or urinary diversion. RESULTS: We identified two groups of patients surgically treated due to LUTD: group 1 included 16 patients (eight male, eight female) aged 4 to 39 years (median 19 years) with bladder augmentation, whereas in group 2, seven patients (five male, two female) 7 months to 31 years old (median 17 years) with incontinent urinary diversion were reported. In the first group, surgical complications after kidney transplantation included one urinary fistula, one ureteral stenosis. Three patients of second group developed recurrent urinary tract infection. Cumulative graft survival rates of all patients transplanted was 69.4% after 15 years, whereas in the two investigated groups, group 1 and group 2, was 80.7% and 55.5% respectively (P=NS.). CONCLUSIONS: Drainage of transplanted kidneys into an augmented bladder or urinary diversion is an appropriate management strategy when the native bladder is unsuitable. Kidney transplantation in patients with bladder augmentation or urinary diversion for LUTD let achieve similar results to those obtained in the general population with normal lower urinary tracts.

Pharmacokinetic of cyclosporine microemulsion in pediatric kidney recipients receiving A quadruple immunosuppressive regimen: the value of C2 blood levels.

BACKGROUND: The management of cyclosporine therapy in pediatric kidney-transplant recipients is largely based on single center's experience rather than on a univocal pharmacokinetic approach based on therapeutic drug monitoring. A prospective multicenter trial was designed to address the question whether C2 blood level monitoring of cyclosporine microemulsion therapy is feasible in the pediatric setting. METHODS: Sixty-four pediatric kidney-transplant recipients receiving a triple immunosuppressive regimen based on cyclosporine microemulsion had their cyclosporine dose adjusted to the same protocol-defined C2 targets from the time of the transplant until 2 years posttransplant. The interim analyses after 1 year of enrollment is presented in this study. RESULTS: One-year patient and graft survival were 100% and 94.8%, respectively. One-year rejection rate was 15%. C2 management of cyclosporine did not affect graft function: 1-year serum creatinine and glomerular filtration rate were 1.3+/-1 mg/mL and 71.2+/-20 mL/min/1.73 m2, respectively. C2 was the best single-point predictor of the area under the concentration curve throughout the entire follow-up, with a mean coefficient of correlation of 0.97+/-0.01. CONCLUSIONS: C2 management of cyclosporine microemulsion therapy is effective and safe in pediatric kidney-transplant recipients given a combined immunosuppressive treatment.

Skin disorders in patients transplanted in childhood.

Only few data are available on skin disorders in pediatric organ transplant recipients. In order to describe the whole range of dermatological diseases in a population of pediatric organ transplant recipients, we studied a group of 217 consecutive organ transplant recipients (168 kidney, 29 heart, 19 liver, one lung) aged <18 years at transplantation followed at a single center. A total of 193 patients showed at least one skin disorder; 149 had more than one skin disease. The most common skin infections were warts (24.4%), pityriasis versicolor (20.7%), folliculitis (12.9%), intertrigo (6.5%); the most common drug side effects were hypertrichosis (69.6%), steroid acne (39.6%), gingival hyperplasia (29%) and severe xerosis (20.7%). Two patients (0.9%) developed nonmelanoma skin cancer. Our study summarizes the main skin complications in patients transplanted in childhood and underlines the necessity of regular dermatologic surveillance of these patients.

One-year results of basiliximab induction and tacrolimus associated with sequential steroid and MMF treatment in pediatric kidney transplant recipient.

We report the 1-year results with a triple immunosuppressive regimen in pediatric recipients of a first kidney transplant, in order to evaluate its safety and efficacy in the prevention of acute rejection and in the reduction of steroid side effects. The immunosuppression is as follows: (i) basiliximab (20 mg if body weight >30 kg; 10 mg if < 30 kg) is given pretransplant and at day 4; (ii) tacrolimus (Tac) is administered in order to obtain blood trough levels of 10-20 and 5-10 ng/ml during and after the first 2 months post-transplant, respectively; (iii) steroids are tapered during the first 6 months and then replaced by mycophenolate mofetil (depending on previous rejection episodes, infection status and the result of a routine biopsy) at a dosage of 4-600 mg/m(2) body surface area. Fifty-three children (median age 13 years, range 2-20) have entered this protocol. One-year patient and kidney survival are 100% and 94% respectively. During the first year a total of nine rejections in seven patients (13% of the cohort study) occurred, all but one responsive to steroids. Renal function was satisfactory throughout the first year (mean CrCl was 63.8 +/- 18 and 60.9 +/- 15.5 ml/min/1.73 m(2) at 6 and 12 months respectively). Subclinical signs of rejection were absent in more than 80% of biopsies (grade I Banff) at 6 months (n = 47); at the 12th month biopsy (n = 42) score I was stable in 20 patients (16 after stopping steroids) and had worsened in eight biopsies (six after stopping steroids). Major complications were insulin-dependent diabetes in three (5.6%) children with the need of insulin for a mean of 3 months; transient hyperglycemia (11 patients), treated with a dietary regimen, symptomatic viral infections (in 11 patients: two parvovirus B19, three cytomegalovirus and two Epstein-Barr virus systemic infections, three interstitial pneumonia, two BK nephritis). Tac doses more than 0.3-0.4 mg/kg/day are at significantly higher risk of viral infection. In conclusion, this immunosuppressive regimen is associated with a low percentage of clinical (13%) and subclinical rejections, but with a relatively high number of infections, prevented by a reduction in Tac doses (<0.3 mg/kg/day) during the first 2 months after transplantation. The assessment of steroid withdrawal needs a longer follow-up.

Renal transplantation. Strategies to prevent organ rejection--the role of an inter-regional reference center.

This paper summarizes the role of the Inter-Regional Reference Center (RC) of the North Italy Transplant program (NITp), in coordinating a donor procurement and organ transplantation network, with a special focus on the strategies to minimize immunological risk and complications after transplantation. In the NITp, patients enrolled on the renal transplantation (RT) waiting list are typed for HLA-A,B,DRB1 antigens with a genomic method. They are periodically screened for the presence of lymphocytotoxic antibodies in their serum by the RC and their suitability to receive the transplant is checked periodically. Cadaver kidney allocation is ruled by a computerized algorithm, named NITK3, established in 1997, which aims at ensuring quality, equity, transparency and traceability during all the phases of the allocation decision-making process. NITK3 has been set up by the NITp Working Group on the basis of biological, medical and administrative criteria and it is periodically reviewed after the analysis of transplant results. In this paper, we show the results of a preliminary analysis of RTs performed from 1998 to 2002 in nine out of sixteen centers of the NITp area, which demonstrates the general quality of the NITp program in terms of patients and graft survival and the special attention to the patients at higher immunological risk.

Renal transplantation in prune-belly syndrome.

We assess the effect of the prune-belly syndrome (PBS) on renal transplantation outcome. Six renal transplantations were performed in five boys affected by PBS (median age 5.8+/-2.1 years, median weight 13.6+/-2.4kg). Renal graft survival, graft function, lower urinary tract dysfunction, urinary tract infections (UTIs), associated complications and patients' survival after 1 and 5 years of follow-up were analysed. The rate for 1-5-year graft survival was 66.7% (mean serum creatinine 98-103 micromol/l). The surgical treatment of the documented bladder obstruction (two patients) and the severe abdominal wall deficit (one patient) led to a reduction of UTI: the patients maintained their native urinary tract and none received prophylactic antibiotics. The lack of abdominal wall musculature led to severe mechanical complication in one patient, but Monfort's abdominal wall reconstruction was able to restore the graft's function. The outcome of patients with PBS who undergo renal transplantation is good. Before the transplant, an accurate assessment of urinary tract anomalies and deficiency of the abdominal wall musculature is mandatory, to program the appropriate treatment and obtain a good long-term prognosis for the renal graft.

Chronic peritoneal dialysis catheters in children: a fifteen-year experience of the Italian Registry of Pediatric Chronic Peritoneal Dialysis.

OBJECTIVE: To analyze data on 503 chronic peritoneal dialysis (CPD) catheters implanted between 1986 and 2000 in pediatric patients enrolled in the Italian Registry of Pediatric Chronic Peritoneal Dialysis (the Registry), comparing three different time periods: 1986-1990, 1991-1995, and 1996-2000. DESIGN: Retrospective study. SETTING: 23 dialysis centers participating in the Registry. METHODS: Data were collected from questionnaires filled in every year. The information for each peritoneal catheter included type, site and technique of insertion, exit-site orientation, exit-site care, complications, survival, and reason for removal. PATIENTS: 503 catheters were implanted in 363 pediatric patients aged younger than 15 years at the start of CPD: 97 catheters in patients under 2 years of age, 67 in patients aged 2-5 years, and 339 in patients over 5 years of age. Mean patient age at onset of CPD was 8.0 +/- 5.1 years. All catheters were surgically implanted and omentectomy was performed in 82.4% of cases. The catheters used were Tenckhoff [468 (93.0%): 443 double cuff, 25 single cuff] and double-cuffed Valli [35 (7.0%)]. The entry site was in the midline in 153 cases (30.4%) and paramedian in 350 (69.6%). RESULTS: During 9048 dialysis-months we observed 451 catheter-related complications, yielding an incidence of 1 episode/20.1 CPD-months: 330 catheter infections (exit-site and/or tunnel infections), 26 leakages, 26 dislocations, 24 obstructions, 22 cuff extrusions, 6 hemoperitoneums, 17 others. 171 catheters were removed due to catheter-related causes; exit-site and/or tunnel infections were the main cause for removal (75.4%), followed by obstruction, dislocation, outer-cuff extrusion, and leakage. Younger children (< 2 years) had a higher risk of infectious causes of catheter removal compared to children aged 2-5 years (p = 0.004) and over 5 years of age (p = 0.002). During the 15-year observation period, a significant reduction in the incidence of leakage was observed and risk of leakage was lower in catheters with paramedian entry site compared to catheters with midline entry site. Removal and replacement of peritoneal catheters during the same surgical operation was performed in 76.3% of catheter removals. Catheter survival rate was 78.1% at 12 months, 58.5% at 24 months, 43.8% at 36 months, and 34.6% at 48 months. No difference in catheter survival was observed in younger children (< 2 years) compared with the two other age groups: < 2 years versus 2-5 years hazard ratio 0.7, 95% confidence interval (95%CI) 0.4-1.2; < 2 years versus > 5 years hazard ratio 0.8, 95%CI 0.5-1.1. CONCLUSIONS: In this survey, we observed better catheter survival in comparison with data reported by the Registry in 1998. Catheter survival improved especially in younger children (< 2 years), a group that previously had a decreased catheter survival rate compared to older age groups. In addition to the progressive increase in experience acquired by dialysis centers, this upward trend may also be related to greater use of double-cuffed catheters, with paramedian exit site, and a higher frequency of omentectomy.

Selective decrease in urinary aquaporin 2 and increase in prostaglandin E2 excretion is associated with postobstructive polyuria in human congenital hydronephrosis.

This study was undertaken to determine the role of aquaporin 2 (AQP2) in the impaired urinary concentrating capacity observed in patients who underwent pyeloplasty because of congenital unilateral hydronephrosis as a result of pyeloureteral junction disease. Twelve children (mean age, 8 +/- 2 mo) were examined in the study. From day 1 to day 5 after surgery, the urine was collected separately from pyelostomy draining only from the postobstructed kidney and from the bladder catheter draining mostly from the contralateral kidney used as internal control. After pyeloplasty, the postobstructed kidney was characterized by a reduced urinary excretion of AQP2 (approximately 54%) associated with polyuria that persisted from day 1 to day 5 (433 +/- 58 versus 310 +/- 74 ml/24 h at day 1; 326 +/- 44 versus 227 +/- 26 ml/24 h at day 5). In parallel, urine osmolality from the postobstructed kidney was significantly reduced compared with the contralateral kidney (111 +/- 12 versus 206 +/- 49 at day 1; 136 +/- 24 versus 235 +/- 65 mOsm/kg at day 5). Creatinine clearance from the postobstructed kidney was not significantly different compared with the contralateral kidney throughout the 4 d after surgery. However, on day 5, creatinine clearance from the postobstructed kidney became significantly lower. Prostaglandin E2 in the urine from postobstructed kidneys was found to be twofold higher than in the contralateral samples (26.0 +/- 6.7 versus 13.5 +/- 2.5 at day 5). It is concluded that (1) the selective downregulation of AQP2 in postobstructed kidney may account for the higher excretion of hypotonic urine, and (2) the local increase in prostaglandin E2 synthesis in postobstructed kidney may be involved in AQP2 downregulation and in maintaining a GFR similar to that of the contralateral kidney.

A multicenter experience on patient and technique survival in children on chronic dialysis.

In this study we compared patient and technique survival of 163 new hemodialysis (HD) patients (age 11.4+/-3.1 years) and 295 peritoneal dialysis patients (7.7+/-4.8 years. P< 0.001), treated in 23 dialysis centers participating in the Italian Registry of Pediatric Chronic Peritoneal Dialysis (CPD) during the years 1989-2000. Three HD (1.8%) and 17 CPD (5.8%) patients died; the overall average death rate was 9.8/1,000 patient-years in HD and 29.8/1,000 patient-years in CPD patients. No statistically significant difference in patient survival between CPD and HD was found, while the survival of 102 CPD children younger than 5 years at the start of dialysis was lower ( P=0.0001) than that of 193 CPD and 160 HD patients aged 5-15 years. We registered 12 modality failures among HD (7.4%) patients and 44 among CPD (14.9%) patients. The main causes were vascular access failure and patient choice in HD, and infection in CPD patients. Technique survival was lower ( P=0.007) in CPD than in HD patients; a statistically significant difference ( P=0.01) was also observed between both the 0- to 5- and the 5- to 15-year-old CPD patients and the HD patients aged 5-15 years. Logistic regression analysis confirmed age at initiation of dialysis to be a predictor of patient death ( P=0.0001) in the whole patient population, and of technique failure in HD ( P=0.006) but not in CPD patients ( P=0.16).

Hyperhomocysteinemia and protein damage in chronic renal failure and kidney transplant pediatric patients--Italian initiative on uremic hyperhomocysteinemia (IIUH).

BACKGROUND: Plasma homocysteine, a new cardiovascular risk factor in both children and adults, is higher in chronic renal failure or kidney transplant patients. This alteration has been linked, in chronic renal failure, to plasma protein damage, represented by increased L-isoaspartyl residues. We measured plasma homocysteine levels and plasma protein damage in pediatric patients from four different Italian regions with conservatively treated renal failure; hemodialysis, continuous ambulatory peritoneal dialysis (CAPD), or transplants, to establish the presence of protein damage and the relative role of hyperhomocysteinemia. METHODS: High performance liquid chromatography (HPLC) separation measured total plasma homocysteine levels, using precolumn derivatization with ammonium 7-fluorobenzo-2-oxa-1, 3-diazole-4-sulphonate (SBD-F). Plasma protein L-isoaspartyl residues were quantitated using human recombinant protein carboxyl methyl transferase (PCMT). RESULTS: In all patient groups, homocysteine levels were significantly higher with respect to the control (Control: 6.87 +/- 0.73 microM) conservatively treated, 14.19 +/- 1.73 microM; hemodialysis, 27.03 +/- 4.32 microM; CAPD, 22.38 +/- 3.73 microM; transplanted, 20.22 +/- 2.27 microM, p < 0.001 vs. control]. Plasma protein damage was significantly higher in conservatively treated, hemodialysis (HD) and CAPD patients, while in transplant patients it was no different from the control. CONCLUSIONS: We concluded that in pediatric patients of different Italian geographical origin, plasma homocysteine levels were significantly higher in all groups with respect to healthy children; therefore contributing to the elevated cardiovascular risk present in these patients. Plasma protein L-isoaspartyl content was higher in renal failure patients, but kidney transplant patients had normal levels, indicating that this kind of protein damage relates more to the toxic action of uremic retention solutes, than to plasma homocysteine levels.

CMV and BKV ureteritis: which prognosis for the renal graft?

This report describes two cases of ureteral stricture in renal graft recipients related to cytomegalovirus (CMV) and human polyoma BK virus (BKV) ureteritis with the same onset characterized by acute graft failure with no clinical signs of systemic viral infections. The histological analysis did not show other causes of graft impairment (i.e. drug toxicity and acute rejection). Ultrasound scan (US) revealed absent or mild hydronephrosis. The diuretic-MAG3 renal scan showed a urinary flow obstruction. The viral genomes were isolated from urine, peripheral blood and graft or ureteral tissues samples. A percutaneous nephrostomy confirmed the stricture, but it restored urine flow only in the graft affected by CMV ureteritis, the association with a specific antiviral therapy probably produced a stable restoration of graft function. In BKV ureteritis,the graft prognosis was poor; graft loss could be due to the progress of BKV nephropathy. A correct differential diagnosis of the etiologic agent responsible for the ureteritis is mandatory, because treatment and outcome of the infection are different.