Use of new peritoneal dialysis solutions in children.

Standard peritoneal dialysis (PD) solutions with low pH and containing high concentrations of lactate and glucose have been demonstrated to negatively affect the peritoneal membrane, mesothelial cell viability, residential peritoneal cells, and also to inhibit phagocytic functions. An increasing body of experimental evidence supports the idea that the peritoneal hypervascularization and fibrosis observed in long-term PD are causally related to the acute and chronic toxicity of conventional PD solutions. A Physioneal (lactate/bicarbonate mixed buffer pH 7-7.4), Physioneal, Extraneal (7.5% icodextrin), Nutrineal (1.1% amino-acid-containing solution) regimen, for example, offers a significant reduction in carbohydrate load (approximately 40-50%), lower exposure to and absorption of glucose degradation products, reduced oxidative stress, and improved volume control when compared with a first-generation DDDD (4 x Dianeal) regimen. The positive aspects of each solution that we have observed in our patients allow a recommendation on the potential benefit of using these solutions in children treated with PD. In fact, data from the literature as well as the results of the studies reported in this paper show that in children the application of neutral pH bicarbonate/lactate-buffered solution for the standard nighttime APD prescription, icodextrin solution for a long daytime dwell, and AA-based solution in malnourished patients is safe and effective. Extended clinical trials should be encouraged to better define the PD schedules for the combined use of these solutions that may be associated with the best clinical efficacy and the highest level of biocompatibility.

Podocin-related mechanisms in posttransplant [corrected] recurrence of focal segmental glomerulosclerosis [corrected].

Posttransplantation recurrence of focal segmental glomerulosclerosis (FSGS) is one of the most disarming events in human pathology with important social and psychological consequences. It usually occurs in 30% to 50% of patients affected by the primary form of the disease with an abrupt onset in the majority of cases occurring within 1 month of the transplantation. Prediction of recurrent cases and early therapy with plasmapheresis are the main goals of the therapy. Although the mechanism of posttransplantation recurrence is still obscure, it has been proposed to be of a multifactorial origin, in which plasma factors determine the shedding of proteins of the slit-diaphragm, such as nephrin and podocin, with structural alterations of the ultra-filtering unit of the glomerulus. Low resynthesis of podocin and/or haplo-insufficiency due to heterozygous mutations should represent significant predisposing factors to proteinuria. In this review, the role of podocin in posttransplantation recurrence will be evaluated focusing on the possibility that resynthesis of the protein could represent a key step also for stable normalization of the renal filter. The recent characterization of the podocin promoter cis- and trans- acting elements and the possibility to characterize low- and high-podocin producer haplotypes offer opportunities to evaluate the capacity for podocin resynthesis in the donor kidney. A review of the literature on posttransplantation recurrence of FSGS in patients originally carrying homozygous and/or heterozygous NPHS2 mutations supports the general idea of a multifactorial origin of the primary disease that can be extended to the pathogenesis of posttransplantation recurrence.

Mycophenolate mofetil pharmacokinetic monitoring in pediatric kidney transplant recipients.

This open-label, longitudinal, long-term study of de novo pediatric renal transplant recipients was designed to investigate the pharmacokinetics (PK) of mycophenolic acid (MPA) and its possible interaction with cyclosporine (CsA). Thirty-four children on an immunosuppressive regimen of CsA, prednisone, and mycophenolate mofetil (MMF, 300-400 mg/m2 twice daily) were investigated at 6, 30, 180, and 360 days after transplantation. Considerable interindividual variability in the areas under the concentration curve (AUC(0-12)) of MPA was observed during the follow-up, although the dose of MMF remained the same over the same time. Predose levels (C0) increased significantly during the first 6 months after transplantation: C0 at 6 and 180 days after transplantation was 0.8 +/- 0.6 and 1.9 +/- 1.1 microg/mL (P < .0001). A significant time-dependent increase in the AUC of MPA was also observed during the first 6 posttransplant months: AUC(0-12) at 6 and 180 days after transplantation was 23.3 +/- 10.8 and 40 +/- 11.6 mg*h/L (P = .003). MPA concentrations 3 and 4 hours after MMF intake were the individual time points that best correlated with the full MPA AUC (r = 0.8 and 0.79; P < .001). The abbreviated MPA AUC (0-4 hours) correlated reasonably with the full AUC (r = 0.87; P < .001). Finally, a significant reduction in CsA dose during the first 6 posttransplant months (P < .001) matched the significant increases in both MPA C0 and full MPA AUC, thus demonstrating the interaction of the 2 immunosuppressive drugs. These observations suggest the need for therapeutic drug monitoring when adjusting the dose of MMF in children.

Cyclosporine enhances the synthesis of selected extracellular matrix proteins by renal cells "in culture". Different cell responses and phenotype characterization.

Glomerulosclerosis and interstitial fibrosis are 2 major side effects of protracted therapy with CsA in heart transplant patients and in nonrenal immunologic diseases. To investigate whether there is any cause-effect correlation between CsA and the synthesis of extracellular matrix in the kidney, we determined the amount and composition of collagens produced by various renal cells "in culture" upon exposure to increasing levels of CsA. The cellular models we used included primary cultures of both human and rat mesangial cells (hMC, rMC), human and rat renal fibroblasts (hFib, rFib), and human tubular epithelia as well as cell lines of rat renal fibroblasts (NRK49F) and of tubular epithelia (NRK52E). In the case of primary cell cultures, CsA induced a marked increment of total collagen synthesis. This was highest for renal fibroblasts (+330% hFib, +110% rFib), followed by rMC (+170%), hMC (+100%), and human tubular epithelia (+130%). At the highest dosage of CsA (5 ng/ml), this corresponded to a net increment in collagen III synthesis by both hMC and hFib (+150% and +300%), while collagen I and collagen IV were unaffected. On hMC, CsA also induced a maximal increase in a component with 70 kDa molecular mass, which was produced only in a negligible amount by these cells in standard conditions. This low molecular mass collagen was tentatively characterized by cyanogen-bromide digestion and fingerprint analysis as a novel molecule showing a peptide composition without comparable features for any reported collagen map. NRK49F and NRK52E cell lines were not affected by CsA. Taken together, these observations demonstrate that CsA is able to induce the synthesis of specific collagens, mainly of collagen III and of a 70-kDa component, by various renal cells in cultures. Since the same cells are the renal site of production of extracellular matrix in pathological conditions, we hypothesize that this effect is a relevant one in the pathogenesis of glomerulosclerosis/interstitial fibrosis during protracted therapies with CsA.

Polyomavirus BK infection in pediatric kidney-allograft recipients: a single-center analysis of incidence, risk factors, and novel therapeutic approaches.

BACKGROUND: Although a growing body of literature regarding polyoma BK virus (BKV) infection and associated interstitial nephritis in kidney-allograft recipients is becoming available, the impact of BKV infection in the pediatric population has not been fully evaluated. METHODS: In a retrospective analysis, we performed polymerase chain reaction (PCR) assays for BKV DNA in serum and urine samples from 100 pediatric kidney-allograft recipients referred to our institution in the last 5 years. RESULTS: BKV viruria was observed in 26 of 100 patients, whereas BKV viremia was demonstrated in 5 patients. Serum creatinine was significantly higher in recipients with positive BK viremia compared with BKV DNA-negative patients (mean 2.66 vs. 1.14 mg/100 mL). Renal biopsy performed in 3 of 5 patients showed graft damage consistent with interstitial nephropathy. In the univariate analysis, negative antibody status of the recipient and the presence of mycophenolate mofetil in baseline immunosuppression were the two factors predictive of active BKV infection. CONCLUSIONS: Our study shows that BKV-associated nephropathy is a relevant complication in the pediatric kidney transplantation setting also. Identification of patients at risk of developing virus-associated nephropathy, through prospective quantification of viral load, could improve clinical outcome by allowing the use of timely preemptive therapy guided by BKV DNA levels.

Branchio-Oto-renal syndrome: a report on nine family groups.

This study reviews nine new families with branchio-oto-renal (BOR) syndrome (Online Mendelian Inheritance in Man [OMIM] 113650). Diagnosis was made by studying 10 index cases, and then 22 other previously undetected patients were diagnosed within the nine families. The syndrome consists of conductive, sensorineural, or mixed hearing loss; preauricular pits; structural defects of the outer, middle, or inner ear; renal anomalies; lateral cervical fistulas, cysts, or sinuses; and/or nasolacrimal duct stenosis or fistulas. In our study, all patients first diagnosed in each familial group were recognized on the basis of severe renal anomalies associated with at least one of these symptoms. Our study showed that BOR syndrome is a misdiagnosed disorder, usually recognized in the presence of severe renal failure but often not diagnosed, especially in the adult in the presence of other isolated clinical signs, such as mild branchial or urological anomalies. We stress the meticulous search we performed for renal anomalies and/or hearing loss in all subjects showing minimal signs of branchial defects. BOR syndrome should be suspected in all cases of isolated urological anomalies, even if no other signs of the syndrome are present. After BOR syndrome has been diagnosed in a patient, all family members should be examined for the presence of the syndrome, even if there are only minimal stigmata of the disease.

Clinical and molecular heterogeneity of juvenile nephronophthisis in Italy: insights from molecular screening.

Autosomal recessive nephronophthisis (NPH) is a renal disorder histologically characterized by tubulointerstitial lesions that are, in some cases, associated with extrarenal manifestations such as tapeto-retinal degeneration or liver fibrosis. The disease is usually pauci-symptomatic in an early phase but invariably evolves to end-stage renal failure in childhood or early adulthood. The recent discovery of the NPHP1 gene (nephrocystin) has prompted research into putative genotype-phenotype correlations. We screened a population of 68 Italian children (10 multiplex families, 47 sporadic cases) with a clinical and histopathologic picture of NPH and found a large homozygous deletion at 2q13 involving nephrocystin in 30 cases, and heterozygous deletion associated with new point mutations at exons 15 (Tyr518Ter) and 17 (Arg585Ter) of the gene in two other cases. The remaining 36 children had no apparent molecular defects of nephrocystin. In spite of this genetic heterogeneity, the two groups, with and without detectable molecular defects of nephrocystin, showed similar renal defects and comparable cumulative survival considering the start of dialysis as an end-point. The unique difference observed was a less frequent requirement of dialysis in NPH1 patients with pure renal form. Finally, tapeto-retinal degeneration was associated with renal lesions in seven cases presenting deletion of the nephrocystin gene and in five sporadic cases without molecular defects. These data show that a molecular defect of nephrocystin is involved in approximately 50% of patients with NPH, and another 50% require further molecular characterization. Research therefore should now be aimed at characterizing a new locus. In spite of the molecular heterogeneity, NPH in children presents similar renal and extrarenal manifestations, thus suggesting the involvement of common pathological routes.

Retinitis pigmentosa, hypopituitarism, nephronophthisis, and mild skeletal dysplasia (RHYNS): a new syndrome?

We report on a 17 6/12-year-old boy with nephronophthisis, retinitis pigmentosa, left upper eyelid ptosis, enopthalmos, transmissive deafness, GH and TSH deficiency, and mild skeletal dysplasia. A similar case was reported by Bianchi et al. [1988: Helv Paediatr Acta 43:449-455] in another Italian patient. Here we confirm the previous observations and argue that both patients might be affected by a new syndrome.

Worldwide demographic aspects of chronic renal failure in children.

Incidence of chronic renal failure in children is not yet clearly known. In recent years it has been evaluated on the basis of the number of patients accepted into dialysis-transplantation programs and is thus underestimated, as registries do not list children who are not treated for technical reasons, lack of facilities or health policy. The number of new patients per year per million child population varies widely. Differences among countries are mainly related to economic development. In developed countries the incidence of CRF remains stable or decreases slowly owing to early diagnosis, improved conservative treatment, prevention of genetically-transmitted diseases, whereas the prevalence increases steadily as a consequence of improved replacement therapy. Causes of primary renal diseases have been analyzed in several series totaling over 9400 children. The most frequent cause is chronic primary glomerulonephritis followed by pyelonephritis, including obstructive uropathies and vesico-ureteral reflux. Differences in geographical distribution of etiologies are also analyzed. The relative contribution of chronic peritoneal dialysis and hemodialysis in the treatment of children with ESRF varies from country to country. Several problems regarding CRF in children are briefly discussed: prevention of renal failure, extension of treatment opportunities to more children, quality of replacement therapy, and clinical rehabilitation of children.

Selective enhancement by cyclosporin A of collagen expression by mesangial cells 'in culture'.

Extracellular matrix deposition in mesangial areas leading to glomerulosclerosis is the major side effect of protracted therapies with cyclosporin A. In order to define any direct correlation between a chronic therapy with the drug and glomerulosclerosis we studied the effects of cyclosporin A on extracellular matrix production by human mesangial cells in culture. By immunoprecipitation and sodium dodecyl sulfate polyacrylamide electrophoresis (SDS-PAGE) of [3H]proline-labeled mesangial cells it was found that cyclosporin A induced a dose-dependent increase in total collagen synthesis (+80%), corresponding to a net increment in collagen III (+120%) and in a component with 70 kDa molecular weight which was produced only in negligible amount by mesangial cells under standard conditions. This collagen was characterized by cyanogen bromide digestion and finger print analysis as a novel molecule, not sharing any peptide composition similarities with the already characterized collagens. These data indicate that cyclosporin A stimulates the synthesis by mesangial cells of selected collagens, mainly collagen III and a new low molecular weight component. This mechanism may be relevant in cyclosporin A induced glomerulosclerosis occurring during protracted therapies with the drug.

Protracted high-dose interferon gamma therapy for chronic experimental nephropathy.

This study focused on the utility of interferon gamma (IFN gamma) as an anti-fibrotic drug in renal experimental fibrosis; the nephropathy was induced by two doses of Adriamycin (ADR) in 20 Sprague Dawley rats, 10 of which were randomly assigned to receive IFN gamma (45,000 UI) on alternate day for 16 weeks. At the end of the follow up, ADR rats treated with IFN gamma developed massive proteinuria, slight renal insufficiency, and presented diffuse glomerulosclerosis, tubulo interstitial infiltration and fibrosis. No difference was found in the composition of tubulo-interstitial infiltrates, mainly consisting in CD4+T lymphocytes with a minor component of CD8+T cells, in comparison with rats treated with ADR alone. These observations demonstrate the inefficacy of a protracted high-dose treatment with IFN gamma in chronic experimental nephropathy with interstitial fibrosis.

Normal values of the bioelectrical impedance vector in childhood and puberty.

The purpose of this study was to determine the reference, bivariate, and tolerance intervals of the whole-body impedance vector in Italian children. This was a cross-sectional, multicenter study, and participants were chosen from the general school population. The impedance vector (standard, tetrapolar analysis at 50-kHz frequency) was measured in 3110 subjects, ages 2 to 15 y, and 2044 healthy children (1014 male and 1030 female) with weight and height within the 95th percentile were selected for the analysis (resistance-reactance graph method). The age-specific 95% confidence intervals of mean vectors and the 95%, 75%, and 50% tolerance intervals for individual vector measurements were plotted using resistance and reactance components standardized by the subject's height. Mean vectors from both sexes with separate 95% confidence ellipses were considered as representative of eight different age groups, from 2 to 13 y. There was a statistically significant sex effect on vector distribution from boys and girls in the age group of 14 to 15 y. The impedance vector distribution of children was also compared with healthy adult subjects (354 male and 372 female, age 15 to 85 y). There was a progressive, statistically significant vector shortening from age 2 to 15 y toward the adults' vector position. In conclusion, we established the trajectory followed by the mean impedance vector in children over ages 2 to 15 y and also obtained the reference, bivariate, and 95%, 75%, and 50% tolerance intervals of the impedance vector by age for healthy children, with which the vectors from children with altered body composition can be tested.

Proteolytic activity and free amino acid concentrations in polymorphonuclear leucocytes.

Polymorphonuclear granulocytes (PMN) are valuable tools for evaluating amino acid (AA) metabolism in nucleated cells, although variations of free amino acid concentrations due to the methods used for the separation of the cells and the procedures used for lysis have been reported. Furthermore, analytical variations in PMN AA concentration may be induced by protease activation during preparation, so that free AA detected in cells could originate from proteolysis other than from the physiological metabolic pathways and transport systems. To study this possibility we measured granulocyte protease activity and AA concentrations in cell suspensions processed with and without the addition of antiproteolytic agents. Granulocyte AA concentrations and protease activity in samples treated with antiproteolytics were 8-15 times lower than in samples processed without antiproteolytics. The use of protease inhibitors throughout the sample preparation is necessary for reliable estimation of free AA in granulocytes.

Autoreactive lymphocytotoxic IgM antibodies in highly sensitized dialysis patients waiting for a kidney transplant: identification and clinical relevance.

The contribution of different families of lymphocytotoxic antibodies in the serologic reactivity of 45 highly sensitized dialysis patients (HSDP) (panel reactivity antibody value-PRA greater than 80%) was assessed by analyzing patients' sera for the presence of auto- and alloreactive IgM and alloreactive IgG antibodies. A total of 220 sera was screened at different incubation temperatures, before and after treatment with the reducing agent dithiothreitol, against a large variety of cell targets by means of complement dependent cytotoxicity (CDC) and antiglobulin augmented (AHG) CDC assays. The results allowed to subdivide the HSDP under study into four groups: Group 1 consisted of 13 untransplanted patients and 14 patients with a prior failed graft whose PRA values did not change following DTT treatment. Alloreactive IgG antibodies alone, with anti-HLA specificity, were present in the sera of this patient group. Group 2 consisted of 3 untransplanted patients whose sera did not contain any autolymphocytotoxic antibody but appeared completely unreactive to panel lymphocytes following DTT treatment, thus confirming the presence of alloreactive IgM only endowed with antiHLA reactivity. Group 3 consisted of 4 untransplanted and 4 patients with a prior failed graft whose sera were found to contain in addition to autoreactive IgM also alloreactive IgG antibodies. Their PRA values declined after DTT treatment on average from 96.2% to 45% and from 95% to 52.5%, respectively. Group 4 consisted of 6 untransplanted patients whose PRA reactivity to both autologous and panel lymphocytes completely disappeared following DTT treatment, thus indicating that their sera contained exclusively autolymphocytotoxic IgM antibodies.(ABSTRACT TRUNCATED AT 250 WORDS)

Children on continuous ambulatorial peritoneal dialysis: muscle and plasma proteins, amino acids and nutritional status.

The aim of the study was to investigate plasma and muscle amino acid (AA) levels in children on continuous ambulatory peritoneal dialysis (CAPD) and their relationship to various indices of nutritional status. Ten children with a mean age of 6.4 +/- 5.6 yrs were evaluated. Muscle biopsies and venous blood samples were taken after an overnight fast. Muscle samples were obtained from rectus abdominis. Data were compared with those of a control group of 22 children who were undergoing elective surgery. Informed consent was obtained from the parents. The plasma concentration of most of the essential AA (valine, leucine, isoleucine, lysine, methionine and tyrosine) were significantly reduced and the levels of some non essential AA (aspartic acid, glycine, citrulline, 1-3 methihystidine, taurine + alanine) were significantly higher than in the controls. Muscle intracellular free essential AA concentrations, except the low levels of valine and leucine did not differ significantly from values in the controls. Among non essential AA, aspartic acid, glutamic acid and ornitine showed significantly increased intracellular concentrations. No significant correlations were found between plasma and muscle AA concentration and ASP (alkali-soluble protein)/DNA ratio, serum albumin, transferrin, bicarbonate levels and duration of CAPD. Instead, a significant correlation was noted between the muscle ASP/DNA ratio, an indicator of the amount of cell proteins per cell unit, and age (r = 0.714, p < 0.05). Muscle Branched chain AA levels were significantly correlated to body mass index (BMI) (r = 0.648, p < 0.05).

Analysis of cellular populations in peritoneal effluents of children on CAPD.

The characterization of cellular populations in peritoneal effluents (PE) of CAPD patients has been the subject of few studies. In order to establish a possible correlation between PE cells and clinical parameters, we studied the immunocompetent cells that are found in uncomplicated patients. In this study we used cytofluorimetric analysis to characterize phenotypically immunocompetent PE cells. We studied 17 children with a mean age of 8.7 +/- 5.3 years, who had been on CAPD for a mean duration of 16 months. The patients never suffered from peritonitis. The effluents were collected after overnight dialysis and centrifuged to concentrate cells. Surface phenotype of PE cells was tested with a panel of monoclonal antibodies. The analysis of 40 PE samples showed that the various cell types were present with different frequencies, suggesting that a dominant phenotype cannot be defined. The ratio between M3 positive cells (monocytic-macrophagic lineage) and T3 positive cells (T lymphocytes) showed a tendency to decrease after initiation of CAPD. T4/T8 ratio in all samples did not differ from that of peripheral lymphocytes. A high frequency of activated T cells (41% +/- 13), defined by the presence of DR antigens on T3+ M3- cells, was seen in PE and confirmed by the high frequency of T cells expressing the IL-2 receptor.

The use of the PD Adequest mathematical model in pediatric patients on chronic peritoneal dialysis.

OBJECTIVE: To test the accuracy of the PD ADEQUEST kinetic model in calculating peritoneal transport parameters and to quantify the differences between the results of software simulations and direct measurements in order to assess the reliability of this tool in chronic peritoneal dialysis (PD) pediatric patients. PATIENTS: Twenty-nine patients (mean age: 10 +/- 4 years; range: 4-17), 5 on continuous ambulatory PD, 4 on continuous cycling PD, 19 on nocturnal intermittent PD and 1 in nocturnal tidal PD, all free from peritonitis in the previous 2 months. Fourteen patients were anuric and 15 had a mean glomerular filtration rate of 1.79 +/- 1.23 mL/min, range 0.25-4.82. METHODS: In all patients, 24-hour dialysate and urine collections associated to standard peritoneal equilibration test (PET) were performed using their usual dialytic regimen and fill volume (1023 +/- 159 mL/m2 BSA, range 614-1361). PD ADEQUEST kinetic parameters were compared with pediatric and adult data from literature. The measured weekly normalized total creatinine clearance (CRCL), weekly total Kt/V, and daily net ultrafiltration (UF) were compared with corresponding mathematically modeled values. RESULTS: Kinetic parameters calculated by the PD ADEQUEST program were comparable to adult and pediatric values from previous studies after normalization for BSA. Measured and modeled CRCL and Kt/V showed a good agreement [concordance correlation (rc) 0.937 and 0.768, respectively] with limited median percentage absolute errors (11.6% and 10.2%, respectively). Ultrafiltration showed less favorable results (rc = 0.600 and median percentage absolute error 45%) probably owing to the wide variability of this parameter. When the analysis was restricted to the peritoneal component, the rc coefficients results were 0.745 for CRCL and 0.512 for Kt/V (median absolute error: 11.6% and 15.2%, respectively). CONCLUSIONS: The overall findings of our study show that the PD ADEQUEST kinetic model can be used in pediatric patients for the calculation of kinetic indexes and for mathematical simulation of the various regimens. We also feel that the results yielded by the PD ADEQUEST program are reliable enough for this computerized mathematical model to be used in the prescription management of pediatric patients. Only UF prediction needs to be used with a certain caution on account of the marked variability of this parameter.

Nutritional status in children receiving chronic peritoneal dialysis.

Chronic peritoneal dialysis (CPD), widely used in uremic children, may have contrasting effects on the nutritional status of patients. Metabolic and nutritional abnormalities due to the combined effects of uremia per se, glucose absorption from the dialysate and catabolic factors, such as protein and amino acid losses into dialysate, poor appetite, and recurrent episodes of peritonitis are the most important. Although CPD allows for fewer dietary restrictions and supplies an extra amount of calories by glucose absorbed with the peritoneal fluid, when protein and energy intakes are assessed the protein intake was almost sufficient or more than that prescribed, whereas the energy intake was low. In CPD children the standard deviation score for weight, height, triceps skinfold thickness, and midarm circumference has been reported as more severely impaired in children less than ten years old. Anthropometric parameters did not worsen during CPD treatment. Plasma proteins and albumin are reported as being low in CPD children. The dietary intake and protein losses have been considered to be the most important determinants of the albumin level in CPD patients. The reported average dialysate losses of free amino acids (AA) during CPD in children vary from 0.02 to 0.03 g/kg/day in different studies. The patterns of plasma AA in CPD is represented by reduced levels of branched chain AA and of other essential amino acids and increased concentrations of some nonessential AA. Several factors may influence plasma AA profile: uremia per se, hormonal alterations, protein and AA losses, and dietary intake. A more specific uremic AA pattern is found in muscle, the largest pool of free AA in the body. Studies on muscle AA in adults on CPD are conflicting: some authors have reported several muscle AA alterations, but others have shown an almost normal pattern. Low valine and leucine muscle levels have been reported in children on CPD.

Continuous ambulatory peritoneal dialysis (CAPD) of children with amino acid solutions: technical and metabolic aspects.

The changes in plasma and dialysate amino acids (AA) in 7 continuous ambulatory peritoneal dialysis (CAPD) children after dialysis with a 1% AA solution were compared with a glucose-containing solution. During the AA-exchange, the plasma levels of individual AA reached their peaks after 1 h, with their percentage increments significantly correlated (p less than 0.001) with the ratio of the amount of AA in the bag to the basal plasma concentration. The plasma concentration of methionine, valine, phenylalanine, and isoleucine remained higher than the basal value at 4 h. The amount of AA absorbed was 66% after 1 h, and 86% after 4 h and 6 h, corresponding to 2574 +/- 253 mumol/kg body wt. During glucose-dialysis (1.36%), levels of histidine, methionine, valine, phenylalanine, and isoleucine were significantly decreased in plasma after 1 h, and stayed low throughout the dialysis period. The loss of AA with the peritoneal effluent was 116 +/- 69 mumol/kg/body wt. From this study, it seems that using an AA dialysis solution, with 1 exchange per day, might limit the daily glucose load and compensate for AA losses by supplying an extra amount of AA and by reducing the loss of other AA not contained in dialysis solutions. The AA pattern in plasma following AA-dialysis resembles that observed after a protein meal, with no signs of persistently high, nonphysiological levels.

Chronic peritoneal dialysis catheters in pediatric patients: experience of the Italian Registry of Pediatric Chronic Peritoneal Dialysis.

During the period 1986-1991, 140 pediatric patients [age < or = 15 years at the start of chronic peritoneal dialysis (CPD)], belonging to 15 dialysis centers, were enrolled in the Italian Registry of Pediatric Chronic Peritoneal Dialysis. Data on 188 peritoneal catheters were collected: 161 catheters were Tenckhoff (144 double-cuff, 17 single-cuff), and 27 were two-cuff Valli-type catheters. All catheters were surgically inserted; the entry site was in the midline in 84 cases and paramedian in 104. An omentectomy was performed in 78.8% of the cases. Apart from peritonitis, there were 161 catheter-related complications (103 exit-site infections, 17 leakages, 15 obstructions, 15 outer-cuff extrusions, 5 hemoperitoneum, 6 others) observed during 2687.5 dialysis-months, with an incidence of one complication every 16.7 dialysis-months. Fifty-five catheters (29.2%) were removed; infection (39 cases) was the main cause for removal, followed by obstruction (9 cases), dislocation, and outer-cuff extrusion (2 cases each). Actuarial survival of all catheters was 79.7% at 1 year, 66.6% at 2 years, 42.8% at 3 years, and 39.8% at 4 years. No difference in catheter survival was observed according to the entry site. When considering the age of the patients at catheter insertion, a difference close to statistical significance was found (p = 0.06).