Children with chronic renal failure have reduced numbers of memory B cells

Reduced serum IgG and subclass levels have been demonstrated in children with chronic renal failure. To study possible causes of this reduction, we analysed B cell subset composition, T helper cell frequencies and immunoglobulin (Ig) production capacity in vitro in children with chronic renal failure, with or without dialysis treatment. B cell subsets were characterized by determining CD27, IgM, IgD and CD5 expression within the CD19(+) population. Intracellular expression of interferon (IFN)-gamma, interleukin (IL)-2 and IL-4 in PMA/ionomycin-stimulated peripheral blood mononuclear cells (PBMC) was used to evaluate T helper frequencies. The capacity of B cells to secrete Ig in vitro was determined by measuring IgG(1), IgG(2) and IgM in culture supernatants of anti-CD2/CD28 monoclonal antibody (MoAb)- or SAC/IL-2-stimulated PBMC. Memory B cell numbers (identified as percentage or absolute number of CD19(+) IgM-IgD- or CD19(+)CD27(+) lymphocytes) were lower in children treated with haemodialysis (HD), peritoneal dialysis (PD) and children with chronic renal failure before starting dialysis treatment (CRF) compared to healthy controls (HC) (P < 0.05). Compared with HC, CD5(+) (naive) B cells were reduced in HD-treated patients but not for PD or for children with chronic renal failure before starting dialysis treatment (CRF). No significant differences in CD4(+) T helper cell subsets were found between the groups. However, CRF children had a higher percentage of IFN-gamma producing CD8(+) T lymphocytes compared to HC (P = 0.02). Finally, IgG(1), IgG(2) and IgM production in vitro was similar in the four groups. In conclusion, significantly lower numbers of memory type B cells were found in children with chronic renal failure compared to healthy controls. This reduction may contribute to the low Ig levels found in these children.

Is biopsy required prior to cyclophosphamide in steroid-sensitive nephrotic syndrome?

AIM

The present studywas designed to retrospectively evaluate the use of renal biopsies prior to cyclophosphamide therapy. The aim of the study was to determine in how many cases histological outcome of the biopsies had subsequently changed the decision to treat or refrain from treatment.

PATIENTS AND METHODS

Between January 1980 and September 2001, 85 children with steroid-sensitive nephrotic syndrome (SSNS) underwent a renal biopsy in the University Hospitals of Utrecht and Nijmegen before the start of an 8-week cyclophosphamide treatment. MCNS was suspected in all children because of the following criteria: edema, proteinuria, hypoalbuminemia, absence of macroscopic hematuria and in rare cases microscopic hematuria, no permanent hypertension, normal C3 serum level, a normal glomerular filtration rate as determined by creatinine clearance and age > 1 year. Cyclophosphamide therapy was indicated because of a frequently relapsing (FR) course of illness in 8 children, because of steroid dependence (SD) in 22 children and because of combined FR and SD in 55 children. Steroid-resistant children were excluded from this study.

RESULTS

Histology confirmed the diagnosis MCNS in 84 out of 85 children. In addition to MCNS, IgA deposits were observed in renal specimens of 2 children. In 1 SD child, the initial diagnosis MCNS was changed 3 years later when a repeated biopsy showed progression into focal segmental glomerulosclerosis (FSGS).

CONCLUSION

In summary, no renal biopsy is required prior to cytotoxic therapy in children with uncomplicated steroid-sensitive nephrotic syndrome.

The choice of dialysis solutions in pediatric chronic peritoneal dialysis: guidelines by an ad hoc European committee

OBJECTIVE

To provide guidelines on choosing dialysis solutions for children on chronic peritoneal dialysis (PD).

SETTING

European Paediatric Peritoneal Dialysis Working Group.

DATA SOURCE

Literature on the application of PD solutions in children (Evidence), and discussions within the group (Opinion).

CONCLUSIONS

Glucose is the standard osmotic agent for PD in children (Evidence). The lowest glucose concentration needed should be used (Opinion). Low calcium solution (1.25 mmol/L) should be applied, wherever possible, with careful monitoring of parathyroid hormone levels (Opinion). The use of amino acid-containing dialysis fluids can be considered in malnourished children, although aggressive enteral nutrition is preferred (Opinion). There is insufficient evidence documenting the efficacy of intraperitoneally administered amino acids (Evidence). When ultrafiltration and/or solute removal are insufficient, polyglucose solutions are a welcome addition to the treatment of children on nocturnal intermittent PD (Evidence). However, in the absence of any reported long-term experience with children, their use must be closely monitored (Opinion). Bicarbonate would appear to be the preferred buffer for PD in children, but more in vivo studies are required before it replaces the present lactate-containing solutions (Evidence/Opinion).

Peptide aptamers targeting the hepatitis B virus core protein: a new class of molecules with antiviral activity

A substantial proportion of the worldwide liver cancer incidence is associated with chronic hepatitis B virus (HBV) infection. The therapeutic management of HBV infections is still problematic and novel antiviral strategies are urgently required. Using the peptide aptamer screening system, we aimed to isolate new molecules, which can block viral replication by interfering with capsid formation. Eight peptide aptamers were isolated from a randomized expression library, which specifically bound to the HBV core protein under intracellular conditions. One of them, named C1-1, efficiently inhibited viral capsid formation and, consequently, HBV replication and virion production. Hence, C1-1 is a novel model compound for inhibiting HBV replication by blocking capsid formation and provides a new basis for the development of therapeutic molecules with specific antiviral potential against HBV infections.

Hepatitis B virus nucleic acids circulating in the blood: distinct patterns in HBs carriers with hepatocellular carcinoma

Circulating nucleic acids in serum and plasma are common in a variety of disease conditions. Here, we focus (i) on our approach for the detection of various hepatitis B virus (HBV)-related nucleic acids in liver tissue and in serum, (ii) on the progression of the chronic HBV infection, (iii) on the relation of HBV-specific nucleic acids circulating in the blood of patients with hepatocellular carcinoma, and in general (iv) on the diagnostic potential of circulating HBV nucleic acids.

Circulating hepatitis B virus nucleic acids in chronic infection : representation of differently polyadenylated viral transcripts during progression to nonreplicative stages

PURPOSE

Beside the established maturation of hepatitis B virus (HBV) transcripts at a polyadenylation signal downstream of the HBV x protein open reading frame, maturation at an internal polyadenylation signal has been observed in the chronically infected liver. In the present study, it was the aim to identify the respective circulating full-length and truncated transcripts in plasma/serum of carriers.

EXPERIMENTAL DESIGN

Nucleic acids extracted from sera were analyzed using established PCR and reverse transcription-PCR procedures targeted to HBV x protein gene regions. Amplification products were cloned and sequenced.

RESULTS

Base substitution patterns were determined, which indicated infection stages advanced to different degrees regardless of the transcript type analyzed. HBV full-length RNA (fRNA) showed a high correlation with hepatitis B e antigen and viral DNA, indicative for a replicative infection. In contrast, truncated RNA (trRNA) appeared to be independent of hepatitis B e antigen and showed only a weak association with circulating viral DNA. No correlation was observed between the levels of trRNA and the apparent liver damage as reflected by alanine transaminase levels. An age-dependent representation of fRNA and trRNA was observed: fRNA decreased progressively to low levels, whereas trRNA remained at comparably high values. trRNA and RNA not polyadenylated at either of the two polyadenylation signals were detected even in the absence of any other conventional HBV seromarker, including viral DNA. This was shown for patients with cryptogenic cirrhosis and hepatitis C virus carriers.

CONCLUSIONS

The identification of HBV RNA in human serum has a diagnostic potential for apparent and for inapparent infection stages.

Effective treatment of peritoneal dialysis-associated peritonitis with cefazolin and ceftazidime in children

OBJECTIVE

To evaluate the use of the combination of cefazolin and ceftazidime for initial treatment of peritoneal dialysis (PD)-related peritonitis in pediatric patients.

DESIGN

Retrospective nonrandomized study.

SETTING

Pediatric dialysis units of the University Medical Center of Utrecht and Nijmegen, The Netherlands.

PATIENTS

40 children (median age 5.4 years) who were treated with PD during the study period of 4.5 years.

INTERVENTIONS

All 50 episodes of peritonitis that occurred during the study period were evaluated by review of medical records. Patients were given intraperitoneal ceftazidime 500 mg/L dialysis fluid, and cefazolin 500 mg/L as a loading dose, followed by a maintenance dose of ceftazidime 125 mg/L and cefazolin 100 mg/L, intraperitoneally, 4 times daily. Antibiotics were continued for 14 days.

RESULTS

After identification of the causative microorganism, one of the antibiotics was discontinued in 34 cases, and the antibiotic schedule was adapted in 2 cases. All cases were initially cured within 3 days. In 5 cases (10%), there was a peritonitis with the same organism recurring within 2 weeks after completion of treatment. There were 4 cases of PD-related peritonitis caused by pseudomonas, all of which were cured.

CONCLUSIONS

The antibiotic combination of cefazolin and ceftazidime is effective for the initial therapy of PD-related peritonitis in children. The toxic complications of aminoglycosides are avoided with this combination.

Adsorption of erythropoietin and growth hormone to peritoneal dialysis bags and tubing

OBJECTIVE

To study the adsorption of erythropoietin and growth hormone to dialysis bags and tubing.

DESIGN

In vitro study in which radiolabeled erythropoietin and recombinant human growth hormone were added to small-volume (50- and 250-mL) dialysis bags. Recovery was measured after 15-minute dwells. Experiments were performed in triplicate.

SETTING

University hospital.

RESULTS

Adsorption of erythropoietin and growth hormone was less than 7%.

CONCLUSION

Adsorption of erythropoietin and recombinant human growth hormone to dialysis bags and tubing is minimal. This finding provides another argument in favor of intraperitoneal therapy in pediatric peritoneal dialysis.

Characteristics of peripheral and peritoneal white blood cells in children with chronic renal failure, dialyzed or not

OBJECTIVE

To explore further the mechanisms leading to immune deficiency in chronic renal failure and the role of dialysis treatment in these mechanisms.

DESIGN

Cross-sectional and longitudinal analysis.

PATIENTS

We studied 39 children treated with peritoneal dialysis (PD), 23 children treated with hemodialysis (HD), 33 children not yet dialyzed [chronic renal failure (CRF)], and 27 healthy children. Peritoneal cells were also obtained from PD children for analysis.

METHODS

White blood cells (WBCs) were isolated from blood and peritoneal dialysis effluent by centrifugation. The number of CD2+, CD4+, and CD8+ T cells, B cells, and natural killer cells were measured by flow cytometry.

RESULTS

The total peripheral blood lymphocyte count was lower in PD children (2.6 x 10(9)/L), HD children (2.1 x 10(9)/L), and CRF children (2.0 x 10(9)/L) compared with healthy children (3.1 x 10(9)/L, p < 0.05). The B lymphocyte count was also lower in PD children (0.34 x 10(9)/L), HD children (0.22 x 10(9)/L), and CRF children (0.33 x 10(9)/L) compared with healthy children (0.52 x 10(9)/L, p < 0.01). Numbers of CD4+ T cells were not different, but numbers of CD8+ T cells were lower in PD children (0.56 x 10(9)/L), HD children (0.63 x 10(9)/L), and CRF children (0.53 x 10(9)/L) compared with healthy children (0.77 x 10(9)/L, p < 0.05). The count of natural killer cells was lower in PD children (0.21 x 10(9)/L), HD children (0.17 x 10(9)/L), and CRF children (0.18 x 10(9)/L) compared with healthy children (0.50 x 10(9)/L, p < 0.0001). The CD4/CD8 ratio of lymphocytes in peritoneal effluent was 0.8 versus 1.9 in peripheral blood (p < 0.001). The CD2/CD19 ratio was not different. The cell subsets remained stable during the first year of PD treatment. The CD2/CD19 ratio in peritoneal effluent was higher in children with a peritonitis incidence > or = 1 per year.

CONCLUSIONS

The reduced numbers of B lymphocytes, CD8+ T cells, and natural killer cells found in CRF children, dialyzed or not, may favor the frequent occurrence of infections.

Autosomal dominant Alport syndrome caused by a COL4A3 splice site mutation

BACKGROUND

Alport syndrome (AS) is a clinically and genetically heterogeneous renal disorder, predominantly affecting the type IV collagen alpha 3/alpha 4/alpha 5 network of the glomerular basement membrane (GBM). AS can be caused by mutations in any of the three genes encoding these type IV collagen chains. The majority of AS families (85%) are X-linked (XL-AS) involving mutations in the COL4A5 gene. Mutations in the COL4A3 and COL4A4 genes cause autosomal recessive AS (AR-AS), accounting for approximately 14% of the cases. Recently, autosomal dominant AS (AD-AS) was linked to the COL4A3/COL4A4 locus in a large family.

METHODS

COL4A3 and COL4A4 cDNAs were generated by nested reverse transcription-polymerase chain reaction and were analyzed by DNA sequence analysis. Denaturating high-performance liquid chromatography (DHPLC) was used for mutation and segregation analysis at the genomic DNA level.

RESULTS

In the AD-AS family, a splice site mutation resulting in skipping of exon 21 of the COL4A3 gene was detected. The mutation does not alter the reading frame and is predicted to result in a COL4A3 chain with an internal deletion.

CONCLUSION

As the NC domain is intact, this chain may be incorporated and distort the collagen triple helix, thereby causing the dominant effect of the mutation. The finding of a specific COL4A3 mutation in AD-AS completes the spectrum of type IV collagen mutations in all genetic forms of AS.

Oral L-carnitine does not decrease erythropoietin requirement in pediatric dialysis

The use of recombinant human erythropoietin (rhEPO) has greatly facilitated the treatment of anemia in children with chronic renal failure, but is expensive. Several reports on adult patients have shown that supplementation with L-carnitine can decrease the requirement for rhEPO. The objective of this study was to investigate the effect of oral supplementation with L-carnitine on the rhEPO requirement in children on dialysis. We investigated 16 children on dialysis (11 hemodialysis, 5 peritoneal dialysis) with a median age of 10.2 years. All children were stable on rhEPO treatment at least 3 months before study entrance. After obtaining baseline data, all children were supplemented with L-carnitine 20 mg/kg/day. Data were collected for 26 weeks. Follow-up was completed for 12 patients (8 hemodialysis, 4 peritoneal dialysis). At baseline free carnitine (32+/-18 micromol/l) and total carnitine levels (54+/-37 micromol/l) were normal. At the end of the study free carnitine levels had increased to 97+/-56 micromol/l (P<0.05) and total carnitine levels to 163+/-90 micromol/l (P<0.05). There was no significant change in rhEPO requirement. Hemoglobin level or hematocrit did not change significantly during the study. In conclusion we could not demonstrate a beneficial effect of supplementation with L-carnitine on rhEPO requirement in children on dialysis.

Clinical experience with icodextrin in children: ultrafiltration profiles and metabolism

Icodextrin use in adults provides sustained ultrafiltration (UF) in long-term dwells. No information is available on UF and metabolism in children. In 11 children, a volume of 1,049+/-138 ml/m2 of the study fluid (1.36% glucose, 7.5% icodextrin, 3.86% glucose) was administered for 12 h. Net UF with icodextrin (339+/-147 ml/1.73 m2) did not differ from UF with 3.86% glucose (450+/-306 ml/1.73 m2, P=0.53) and was higher than UF with 1.36% glucose (-87+/-239 ml/1.73 m2, P=0.003). Icodextrin added 0.52+/-0.07 to the weekly Kt/V. Over 6 weeks, icodextrin was used for 12-h daytime dwell. Total icodextrin reached a steady-state level of 2.91+/-1.22 g/l at 2 weeks. The main icodextrin metabolites were maltose, maltotriose, and maltotetraose. After 2 weeks, steady state levels were 2.02+/-0.66 mmol/l, 1.46+/-0.35 mmol/l, and 0.45+/-0.12 mmol/l. No icodextrin or metabolites were detectable 4 weeks after the study. We conclude that 7.5% icodextrin is capable of maintaining UF during 12-h dwell in children and is comparable to UF obtained with 3.86% glucose. Steady-state levels of icodextrin and metabolites were reached at 2 weeks and disappeared after the study.

Immunoglobulins in chronic renal failure of childhood: effects of dialysis modalities

BACKGROUND

It is not clear whether low serum levels of IgG (subclasses), previously demonstrated in children on peritoneal dialysis (PD), are related to the PD procedure or to factors associated with chronic renal failure (CRF). The aim of our study was to analyze the effect of PD on serum and PD effluent (PDE) IgG and subclass levels in children with end-stage renal failure.

METHODS

We measured albumin, IgG, IgA, IgM, and IgG subclasses in serum and PDE from children on PD (N = 40) and compared the serum values with those of children treated with hemodialysis (HD, N = 23) or presenting with CRF but not yet dialyzed (CRF; N = 63), and with a group of healthy controls (HCs; N = 67). Sixteen PD children could be followed sequentially from before starting PD and eight during a peritonitis episode.

RESULTS

Forty percent of the PD children showed reduced serum IgG2 levels (P = 0.0003) compared with 35% in HD (P = 0.006), 33% in CRF (P = 0.001), and 9% in HC children. IgG1 deficiencies were observed in 25% of PD patients (P < 0.0001), 4% of HD (P = NS), 16% of CRF (P = 0.0005), and 0% of HC children. IgG3 and IgG4 deficiencies were observed less frequently. Peritoneal clearances were similar for total IgG, IgG1, IgG2, and IgG4, but were lower for IgG3 (P < 0.05). No relationships were found between clearances and age or duration of PD treatment. Total IgG (P = 0. 003) and IgG1 (P = 0.002) levels declined just after starting PD. Peritonitis was associated with temporarily increased peritoneal loss of Ig, while the serum concentrations were unaffected. No significant relationship was found between the peritonitis incidence and reduced IgG or subclasses. However, all children with two or more peritonitis episodes per year had a reduced Ig level.

CONCLUSIONS

Although the mean serum concentrations of immunoglobulins were normal in all studied groups, a deficiency of one or more IgG subclasses was present in all groups with renal failure, suggesting inhibition of their synthesis by the uremic state. Ig deficiencies were more frequently found in PD, likely caused by protein loss in PDE. A high peritonitis incidence was associated with reduced serum Ig levels.

The clinical spectrum of type IV collagen mutations

Clinical manifestations of type IV collagen mutations can vary from the severe, clinically and genetically heterogeneous renal disorder, Alport syndrome, to autosomal dominant familial benign hematuria. The predominant form of Alport syndrome is X-linked; more than 160 different mutations have yet been identified in the type IV collagen alpha 5 chain (COL4A5) gene, located at Xq22-24 head to head to the COL4A6 gene. The autosomal recessive form of Alport syndrome is caused by mutations in the COL4A3 and COL4A4 genes, located at 2q35-37. Recently, the first mutation in the COL4A4 gene was identified in familial benign hematuria. This paper presents an overview of type IV collagen mutations, including eight novel COL4A5 mutations from our own group in patients with Alport syndrome. The spectrum of mutations is broad and provides insight into the clinical heterogeneity of Alport syndrome with respect to age at renal failure and accompanying features such as deafness, leiomyomatosis, and anti-GBM nephritis.

[Acute renal insufficiency caused by bilateral ureteral obstruction after appendectomy in a 6-year old boy]

A 6-year-old boy developed macroscopic haematuria on the 4th day after appendectomy for acute appendicitis, at which the appendix was found to be perforated. During the next few days the urine secretion decreased and malaise, pain in the lower abdomen, nausea and vomiting occurred. On a management of ample fluid administration, the urine secretion recovered and the symptoms subsided in a few days. In the early postoperative stage after appendectomy in children the possibility should be kept in mind of the development of acute renal insufficiency due to bilateral ureteral obstruction as a result of oedema of the posterior bladder wall, even if by means of ultrasonography only mild to moderate abnormalities are noted. Awaiting decompression by means of the introduction of bilateral ureteric stents, in order to prevent irreversible renal damage, supportive therapy with fluid administration depending on the diuresis seems indicated.

Overexpression of p53 protein is not directly related to hepatitis B x protein expression and is associated with neoplastic progression in hepatocellular carcinomas rather than hepatic preneoplasia

p53 mutations and binding of p53 to hepatitis B virus (HBV) x protein (HBx) have been suggested as alternative mechanisms of development of hepatocellular carcinomas (HCCs) in man, both processes resulting in intracellular accumulation of the protein which is detectable by immunohistochemical approaches. We have examined p53 expression in 149 explanted human livers, including 39 cases infected with HBV and 35 bearing HCC. p53 was demonstrated immunohistochemically in 51% of HCC samples (18/35), localized mainly in fast growing poorly differentiated areas. Accumulation of mutant p53 was verified by immunoprecipitation in most of the positive HCC samples (14/15), implying occurrence of p53 mutations. No cells positive for p53 were found in 354 preneoplastic hepatocellular lesions examined. This indicates that p53 mutation is associated with progression, rather than early development, of HCC in the low-aflatoxin B(1)-exposed region. The intracellular distribution patterns of p53 and HBx were different, with the former within nuclei and the latter confined to cytoplasmic compartment. HBx did not coimmunoprecipitate with p53. These data indicate that p53-HBx binding is infrequent, if it really occurs, in HBV-infected human liver, and that it cannot be a common mechanism of HBV-associated hepatocarcinogenesis. In addition, p53 accumulation was also observed in some parenchymal and ductular (oval) cells in cirrhotic livers and, more frequently, in fulminant hepatitis, being independent of HBx expression, and seemingly associated with the damage and/or regeneration of liver parenchyma, perhaps merely reflecting a cellular stress response.

Ceftriaxone-associated nephrolithiasis and biliary pseudolithiasis

Biliary pseudolithiasis has been reported in patients who received ceftriaxone therapy. In addition to biliary sludge formation occasional reports of ceftriaxone-induced nephrolithiasis have been published. In general, these adverse effects will develop after seven to ten days of treatment. We report on a seven-year-old boy with ceftriaxone-associated biliary pseudolithiasis and nephrolithiasis four days after initiation of treatment. Patients receiving a high dose of ceftriaxone and developing colicky abdominal pain should be considered for ultrasound and a change in antibiotic therapy if appropriate.

Truncated hepatitis B virus RNA in human hepatocellular carcinoma: its representation in patients with advancing age

RNA from tissue samples of 46 HBsAg seropositive hepatocellular carcinoma (HCC) patients was analysed by an RT/PCR assay which discriminates full-length hepatitis B virus (HBV) RNA polyadenylated at the unique viral poly(A) signal governing replication from truncated HBV RNA polyadenylated at a cryptic poly(A) signal. In the tumor the apparent coexistence was less frequent than in the peritumor while the predominance of one of the two RNAs was more frequent. The mean age of patients with a predominance of truncated RNA in the tumor was 9 years above those patients with a predominance of full length RNA (p < 0.05). An inverse relationship existed between the presence of truncated RNA and the presence of RNA carrying core gene sequences. The results of this study establish truncated RNA as a frequent marker of the chronic infection but leave it open whether it is found preferentially in patients developing HCC or generally in chronically infected individuals.

Follow-up study of peritoneal fluid kinetics in infants and children on peritoneal dialysis

OBJECTIVES

To study longitudinal changes in transcapillary ultrafiltration (TCUF) and marker clearance (MC), as a reflection of lymphatic absorption, in children on peritoneal dialysis (PD). To present data on fluid kinetics in infants younger than 2.5 years, using an intraperitoneal volume of 1200 mL/m2 body surface area (BSA).

DESIGN

The study involved a 4-hour dwell of 1200 mL/m2 BSA of dialysis fluid containing 3.86% glucose with Dextran 70 as volume marker. Cumulative TCUF and cumulative MC were measured.

SETTING

A tertiary-care university hospital.

PATIENTS

A follow-up period of 33 months of serial (1 - 4) peritoneal equilibration tests (PETs) was studied in 20 children with a median age of 6.4 years (range 2.1 - 15.4 years). Fluid kinetics in 5 additional infants with a median age of 1.4 years (range 0.5 - 2.5 years) was measured.

RESULTS

Cumulative TCUF was 1041 mL/1.73 m2 at 1 - 3 months after start of PD, 1026 mL/1.73 m2 at 7 - 9 months, 1021 mL/1.73 m2 at 11 - 13 months, and 756 mL/1.73 m2 at 26 - 33 months (NS). Cumulative MC was 235 mL/1.73 m2 at 1 - 3 months after start of PD, 311 mL/1.73 m2 at 7 - 9 months, 395 mL/1.73 m2 at 11 - 13 months, and 509 mL/1.73 m2 at 26 - 33 months (NS). In infants, cumulative TCUF was 755 +/- 237 mL/1.73 m2; cumulative MC was 400 +/- 214 mL/1.73 m2.

CONCLUSIONS

Transcapillary ultrafiltration and marker clearance do not change in children > 2.5 years during the period studied. Fluid kinetics does not differ between infants < 2.5 years and older children when intraperitoneal volumes of 1200 mL/m2 BSA are used.

Treatment of hyperhomocysteinemia in children on dialysis by folic acid

Adult patients with renal failure have a high total homocysteine concentration in plasma. Hyperhomocysteinemia is an independent risk factor for cardiovascular diseases. Folic acid lowers the homocysteine concentrations in plasma in hyperhomocysteinemia. Whether this results in a reduced risk for cardiovascular diseases remains to be proven by intervention studies. In the present study we investigated: (1) if homocysteine concentrations are elevated in the plasma of children with renal failure and (2) the influence of folic acid administration on the plasma homocysteine concentration. The plasma homocysteine concentration was measured in 21 children, 9 on hemodialysis and 12 on peritoneal dialysis, before and 4 weeks after treatment with 2.5 mg folic acid daily. Healthy children (234) constituted the control group. In controls the median homocysteine concentration was 9.1 micromol/l (range 4.3-20.0 micromol/l). The median plasma homocysteine concentration in patients before folic acid treatment was 20.0 micromol/l (Q1-Q3 13.7-26.0; Q, quartile). After 4 weeks of folic acid treatment the median plasma homocysteine concentration was 12.0 micromol/l [Q1-Q3 9.8-14.3 (P<0.0001 Wilcoxon signed rank test)]. There was no significant difference between hemodialysis and peritoneal dialysis patients. Children with renal failure treated with hemodialysis or peritoneal dialysis have elevated plasma homocysteine concentrations, but this is significantly reduced after administration of 2.5 mg folic acid daily for 4 weeks. It is suggested that folic acid be added to the treatment of children with renal failure, although a beneficial effect still has to be proven. The required dose needs further study.

Intraperitoneal hypercoagulation and hypofibrinolysis is present in childhood peritonitis

An increased rate of obstruction of peritoneal dialysis catheters is observed during peritonitis. Hypercoagulation and hypofibrinolysis may explain this increased occurrence. We studied plasminogen activator inhibitor type 1 antigen (PAI-1), tissue-type plasminogen activator antigen (t-PA), D-dimer (DD), plasmin-alpha2-antiplasmin complexes (PAP), and thrombin-antithrombin III complexes (TAT) in 7 children with peritonitis (group A) and 12 children during stable peritoneal dialysis (group B). Albumin, beta2-microglobulin, IgG, and alpha2-macroglobulin were measured for baseline transperitoneal protein transport. After a dwell of 6 h with 1.36% Dianeal, dialysate and serum samples were collected. Dialysate to plasma ratios of all proteins were calculated. During peritonitis (group A) TAT was higher: 34.7 versus 22.0 (P=0.01). PAI-1 was increased in group A: 76.5 versus 22.9 (P=0.004). PAP was decreased during peritonitis (group A): 24.9 versus 39.3 (P=0.01). In group A, DD were decreased. 10.8 versus 26.7 (P=0.002). t-PA was similar in both groups (23.7 in group A vs. 27.7 in group B; P=0.26). In both groups TAT, PAI-1, t-PA, PAP, and DD were significantly higher than in baseline transperitoneal transport, suggesting intraperitoneal production. Hypercoagulability and hypofibrinolysis were present during peritonitis compared with the control situation.

Identification of COL4A5 defects in Alport's syndrome by immunohistochemistry of skin

BACKGROUND

The COL4A3-COL4A4-COL4A5 network in the glomerular basement membrane is affected in the inherited renal disorder Alport's syndrome (AS). Approximately 85% of the AS patients are expected to carry a mutation in the X-chromosomal COL4A5 gene and 15% in the autosomal COL4A3 and COL4A4 genes. The COL4A5 chain is also present in the epidermal basement membrane (EBM). It is predicted that approximately 70% of the COL4A5 mutations prevent incorporation of this chain in basement membranes.

METHODS

We investigated whether or not COL4A5 defects could be detected by immunohistochemical analysis of the EBM. Punch skin biopsies were obtained from 22 patients out of 17 families and two biopsy specimens from healthy males were used as controls.

RESULTS

In four cases with the COL4A5 frameshift or missense mutations, the COL4A5 chain was either lacking from the EBM (male) or showed a focally negative pattern (female). In three other patients with a COL4A5 missense mutation, a COL4A3 and a COL4A4 mutation, respectively, the COL4A5 staining was normal. A (focally) negative EBM-COL4A5 staining was found in three patients of six families with a diagnosis of AS and in one family of a group of four families with possible AS.

CONCLUSIONS

The (focal) absence of COL4A5 in the EBM of skin biopsy specimens can be used for fast identification of COL4A5 defects. Combined with polymorphic COL4A5 markers, both postnatal and prenatal DNA diagnosis are possible in the family of the patient.

Cloning, bacterial synthesis, and characterization of immunoglobulin variable regions of a monoclonal antibody specific for the hepatitis B virus X protein

The nucleotide (nt) sequences encoding the variable regions of the heavy (H) and light (L) chains were determined for a murine monoclonal antibody, 12/231/93, which is specific for a linear epitope located between amino acids 90 and 102 of the hepatitis B virus (HBV) X protein (HBx). The variable (V) regions of the H and L chains were shown to belong to the mouse H chain subgroup II (C) and kappa L chain group III, respectively. The cloned variable region sequences were used for the production of a Fab fragment in Escherichia coli, which had binding activity for membrane immobilized recombinant HBx. These gene sequences may be useful for the study of HBx function in cells that will support HBV replication.

Peritoneal protein loss in children with nephrotic syndrome during peritoneal dialysis

BACKGROUND

The passage of proteins across the glomerular filtration barrier is mainly determined by the size of the protein. In nephrotic syndrome (NS) the glomerular permselectivity is affected, causing proteinuria. Some authors suggest the existence of a generalized basement membrane defect. The permeability characteristics of the peritoneal basement membrane in children with NS are not known.

METHODS

The transperitoneal transport of proteins with a different molecular weight (beta2-microglobulin MW 11800 D, albumin MW 69000 D, IgG MW 160000 D, and alpha2-macroglobulin MW 820000 D) was studied in a study group (group A) consisting of six stable nephrotic children (three with glomerulosclerosis and three with congenital nephrotic syndrome, one of them with mesangial sclerosis) and compared to a control group (group B) consisting of eight stable children on peritoneal dialysis. After a dwell of 6 h with Dianeal 1.36% dialysate and serum samples were collected. For each patient the dialysate to plasma (D/P) ratios of the four proteins were calculated. The D/P ratios of the nephrotic patients in group A were compared to the D/P ratios of the patients in the control group B. Data were expressed as mean +/- SD.

RESULTS

The values for the D/P ratios (in percentage) of beta2-microglobulin, albumin, IgG and alpha2-macroglobulin in group A were 19.6+/-9.9, 2.7+/-1.7, 1.6+/-0.9, and 0.5+/-0.4, compared to 24.9+/-10.2, 4.0+/-2.3, 2.2 +/- 1.2, and 0.7 +/- 0.3 in the control group B. The ratios were plotted against MW on a double logarithmic scale. In all patients a linear relationship between molecular weight and D/P ratio of the proteins was obtained. The D/P ratios of the study group did not differ significantly from the control group.

CONCLUSION

We conclude that the size selectivity of the capillary permeability is not affected in the peritoneal membrane in children with NS due to glomerulosclerosis and congenital nephrotic syndrome.

Expression and purification of single-chain anti-HBx antibody in Escherichia coli

Monoclonal antibodies have been widely used in tumor targeting studies with promising results. However, their clinical application has been limited by heterogeneity and macro-molecular movement of murine antibody. In this study, the variable-region (heavy- and light-chain) fragments of anti-HBx monoclonal antibody were enriched by the polymerase chain reaction. The expression vector, which included a 6x histidine sequence in the 3' terminus of the HBx single-chain antibody (sFv) was recombined with a linker sequence (KLGGGGFSGA) between the variable regions. The expression product from Escherichia coli fused with 6xHis was purified by nickel (Ni2+) nitrilotriacetate chelating resin. The results of enzyme-linked immunosorbent assay and Western blotting showed that sFv had binding affinity with HBxAg, suggesting that it could become a novel targeting carrier in clinical trials.

Expression of hepatitis B virus X protein in HBV-infected human livers and hepatocellular carcinomas

Transactivation of cellular genes and functional inactivation of p53 by the hepatitis B virus (HBV) X gene-encoded protein (HBx) are proposed as alternative mechanisms for induction of hepatocellular carcinomas (HCCs) in chronic HBV infection. Using an immunohistochemical approach, we studied the expression of HBx in 39 explanted livers with HBV-associated disease. Because the data reported previously have been inconsistent, possibly due to the application of different antibodies, we compared results with 5 polyclonal and 6 monoclonal anti-HBx antibodies from five laboratories. Ten of the 11 antibodies reacted with recombinant HBx by Western blotting, but only 1 polyclonal and 2 monoclonal antibodies reacted specifically with HBx in tissue, and were thus suitable for immunohistochemistry. Three other polyclonal antibodies reacted with tissue components in addition to HBx. One polyclonal and 4 monoclonal antibodies did not recognize the HBx in the tissue. HBx was demonstrated in 16 of 30 (53.3%) cirrhotic livers and 10 of 18 (58.8%) HCCs by all specific antibodies. The expression of HBx, among three HBV antigens examined, was found to be preferentially maintained in HCC and the surrounding liver parenchyma, including focal or nodular preneoplastic lesions. However, the immunoreactivity was always limited to the cytoplasm of a small number of parenchymal and neoplastic cells. The role of X gene expression in HBV-associated human hepatocarcinogenesis remains to be established.

Cerebrospinal fluid levels of amino acids in infants and young children with chronic renal failure

Chronic renal failure (CRF) is associated, especially in young children, with delayed cognitive development of unknown origin. As cerebrospinal fluid (CSF) reflects the composition of the extracellular fluid of the brain, not only plasma but also CSF amino acids concentrations were determined in 8 infants (age 2-8 months) and 3 children (age 26, 32 and 56 months) with CRF (creatinine clearance 13 +/- 9 ml/min/ 1.73 m2). In three of these children investigations were repeated after six weeks of CAPD treatment. In the infants, a significant decrease was found in CSF of alpha-aminobutyric acid, valine, isoleucine, leucine, tyrosine, tryptophane, histidine and n-zeta-methyl-1-lysine, whereas there was a significant increase of 3-methylhistidine. In plasma serine, valine, leucine, tyrosine and histidine were significantly decreased, whereas there was a significant increase of aspartic acid, citrulline, and 3-methylhistidine. These abnormalities remained constant after the start of CAPD except for the normalization in CSF and plasma of 3-methylhistidine. These data indicate a generalized disturbance of amino acids in young children with CRF. An abnormal substrate is offered to the neurons and astroglia in children with CRF.

Increase of the bioavailability of intraperitoneal erythropoietin in children on peritoneal dialysis by administration in small dialysis bags

OBJECTIVE

To establish the effectivity of administration of erythropoietin intraperitoneally in a small amount of fluid in children with renal anemia on continuous ambulatory peritoneal dialysis (CAPD).

DESIGN

Prospective study in which children with renal anemia on CAPD were treated with erythropoietin intraperitoneally, administered in a specially designed bag containing 50 mL NaCl 0.9%.

SETTING

University hospital.

PATIENTS

The patient population consisted of 9 children treated with CAPD and 1 treated with nightly intermittent peritoneal dialysis. The median age was 7.8 years (range 4.1-15.2). Four of these children had not been treated with erythropoietin before (group A), and 6 had been treated with erythropoietin administered intraperitoneally in 250 mL of dialysis fluid (group B).

INTERVENTIONS

Patients in group A started on a dose of approximately 300 units/kg per week (group A). Patients in group B received their previous dose. Dosage was adjusted to achieve a target hemoglobin level of 6.5-7.0 mmol/L (104-112 g/L). Serum ferritin levels and transferrin saturation were monitored and iron supplementation was prescribed in the case of iron deficiency.

MAIN OUTCOME MEASURES

Weekly erythropoietin dose in relation to hemoglobin level.

RESULTS

In group A, median hemoglobin level rose from 5.3 mmol/L (85 g/L) to 6.6 mmol/L (106 g/L) after 6 months of therapy, whereas the median erythropoietin dose decreased from 266 to 234 U/kg/week. In group B, hemoglobin levels remained stable and median erythropoietin dose decreased from 262 to 194 U/kg/week. One patient in this group, for unknown reasons, never responded to erythropoietin treatment. He was excluded from further analysis. In the remaining 5 patients the median cumulative erythropoietin dose was 3250 U/kg in the 3-month period prior to the start of the study and 2713 in the 3-month period starting 6 months after the beginning of the study. This difference of 17% was statistically significant using a Wilcoxon test (p < 0.05).

CONCLUSION

Intraperitoneal administration of erythropoietin in a small amount of dialysis fluid leads to a decrease in the required dose.

Cytosolic phospholipase A2 is activated by the hepatocyte growth factor receptor-kinase in Madin Darby canine kidney cells

The hepatocyte growth factor/scatter factor (HGF/SF) receptor which is a transmembrane protein encoded by the Met oncogene, possesses intrinsic tyrosine kinase activity which transduces the mitogenic, morphogenic and the scattering effect of HGF/SF. The pluripotent signal of HGF/SF is transduced through association of the Met receptor with various intracellular adaptors. Phosphorylation of cytosolic phospholipase A2 (cPLA2) is associated with activation of this molecule which in turn leads to arachidonic acid production followed by release of prostaglandins and related compounds exerting their roles onto cell proliferation, chemotaxis and vascular motility. Arachidonic acid and its metabolites were shown to be involved in processes like liver regeneration where growth factor receptors possessing tyrosine kinase activity are implicated. In this study we examined whether stimulation of the HGF/SF-receptor's tyrosine kinase activity would involve changes in the phosphorylation state and the activity of cPLA2 in MDCK cells, where HGF/SF is known to induce scattering responses rather than mitogenesis. The activated p145betaMET was shown to associate with and to phosphorylate cPLA2 on tyrosine residues, this leading to subsequent release of arachidonic acid. cPLA2 was also phosphorylated in serine residues and such a role has been so far assigned to the mitogen activated protein (MAP) kinase. Our data have also shown that MAP kinase is associated and phosphorylated on tyrosine by the activated p145betaMET. Immunodepletion of MAP kinase via electroporation of an anti-MAP kinase antibody, did not significantly decrease arachidonic acid release in HGF/SF-stimulated MDCK cells. It is therefore emerging that phosphorylation of cPLA2 on tyrosine by the HGF/SF receptor kinase is capable of triggering arachidonic acid release and that MAP kinase is contributing to full, but does not drive, the activity of cPLA2. The release of arachidonic acid by MDCK cells following HGF/SF stimulation is establishing this fatty acid and its metabolites as major components involved in the transduction of MET-driven signals and at the same time in the amplification of such signals.

Adequate dialysis? Measurement of KT/V in a pediatric peritoneal dialysis population

OBJECTIVE

To measure the urea and creatinine kinetics in a pediatric population.

PATIENTS AND METHODS

In 19 children treated with peritoneal dialysis (PD) KT/V, urea and creatinine clearances (Ccr) were measured. Thirteen children were on continuous ambulatory peritoneal dialysis (CAPD) and 6 on highly intermittent peritoneal dialysis (NIPD).

RESULTS

Mean KT/V per week was 2.31 +/- 0.78 and mean creatinine clearance 74 +/- 47 L/week/1.73 m2. There was no difference in dialytic KT/V between patients treated with CAPD and NIPD (1.75 +/- 0.21 vs 1.76 +/- 0.50). The correlation between KT/V urea and creatinine clearance was 0.9 (p < 0.001). There was a clear relationship of these parameters with residual renal function, but not with age or blood urea level. A weak positive correlation was found with serum albumin and protein intake.

CONCLUSIONS

Mean KT/V in this patient group was higher than the values reported for most adult patient groups. Residual renal function considerably contributes to this high KT/V. It is not clearly defined which KT/V should be aimed for, since criteria for adequate dialysis are multifactorially determined and therefore difficult to interpret.

Hereditary disorders of the glomerular basement membrane

Increased knowledge of the biochemical composition of the glomerular basement membrane (GBM) and the introduction of molecular genetics has shed new light on the hereditary disorders of the GBM. In this review three disorders are highlighted. About 85% of the cases reported as Alport syndrome are transmitted as the X-linked form and are due to mutations of the COl4A5 chain localized at Xq22. The autosomal recessive form can be explained by mutations in the COl4A3 and COl4A4 gene. Anti-GBM nephritis leading to loss of the renal allograft in about 1%-5% of transplanted Alport patients can be the tragic consequence of this disorder. Some patients with familial benign hematuria have an abnormality of COl4A4. The nail-patella syndrome is a rare autosomal dominant disorder defined by the association of nail dysplasia, bone abnormalities, and frequently renal disease. The gene is localized in region 9q34.1, COl5A1 is not involved. The Finnish type is the best known of the different forms of congenital nephrotic syndrome. The gene has been mapped to the long arm of chromosome 19. Diffuse mesangial sclerosis occurs in the isolated form and as part of the Denys Drash syndrome. Disturbances of the WT1 function in the epithelial cells can have a role in the renal abnormalities of the Denys Drash syndrome.

The hepatocyte growth factor receptor kinase-mediated phosphorylation of lipocortin-1 transduces the proliferating signal of the hepatocyte growth factor

Hepatocyte growth factor (HGF), which is identical to scatter factor (SF) through coupling to its receptor the product of c-met oncogene, was found to induce proliferation of A549 lung carcinoma cell line, accompanied by release of prostaglandin E2 (PGE2). This activity was sensitive to 0.1-100 microM indomethacin and to 5-50 nM of verapamil. Lipocortin-1, a dexamethasone-inducible inhibitor of phospholipase A2, was shown to be phosphorylated on tyrosine 10 min upon addition of HGF and to translocate to the membrane fraction for up to 6 h upon ligand stimulation. Lipocortin-1 was found to associate in vivo with the HGF receptor species, and this association was independent of the phosphorylation state of the beta-subunit of the HGF receptor (p145betaMET. Immobilized HGF receptor kinase species associated and phosphorylated in vitro lipocortin-1, thus providing evidence that lipocortin-1 is directly phosphorylated by the p145betaMET. Incubation of A549 cells with antisense 21-mer lipocortin-1 oligonucleotides reduced the synthesis and the HGF-stimulated phosphorylation of lipocortin-1 as well as the HGF-stimulated cell proliferation. In processes where the HGF receptor tyrosine kinase is activated, phosphorylation of lipocortin-1 may function as a "signal amplifier" promoting the release of intercellular messengers (PGE2) with pluripotent roles in cell proliferation, chemotaxis, and vascular remodeling.

DNA sequence requirements for the activation of a CATAAA polyadenylation signal within the hepatitis B virus X reading frame: rapid detection of truncated transcripts

Truncated hepatitis B virus transcripts terminating downstream of a cryptic CAUAAA polyadenylation signal within the HBx open reading frame have previously been identified in tissue samples from two patients with hepatocellular carcinoma (Hilger et al., 1991, J. Virol. 65, 4284-4291). In this study an HBx expression plasmid was systematically deleted in order to elucidate the DNA sequence context which is required for the conversion of the usually inactive CAUAAA motif into a functional polyadenylation signal. Deletions were made progressively on a stretch of viral DNA which, seen on the transcript level, started downstream of the established UAUAAA polyadenylation signal and proceeded to the cryptic CAUAAA motif. The plasmid constructs obtained were used to transfect cells of the HepG2 line. The analysis of newly synthesized RNA via an RNase protection assay revealed termination downstream of the CAUAAA motif following the removal of GU-rich auxiliary sequences downstream of the poly(A) addition site of the UAUAAA signal. Similar results were obtained when an anchored oligo(dT) primer which recognizes selectively truncated RNA was used for the differential, RT/PCR-mediated amplification of 3'-ends. Thus it could be documented in two ways that inactivation or removal of the UAUAAA signal rendered the CAUAAA motif functional as a poly(A) signal. On the basis of the results obtained, we suggest that chromosomally integrated viral DNA on which the TATAAA motif is removed may constitute a template for truncated as well as for virus/cell hybrid transcripts. We also suggest the use of anchored oligo(dT) primers for the rapid identification of truncated transcripts in tissue samples of HCC patients.

Benign familial hematuria due to mutation of the type IV collagen alpha4 gene

Benign familial hematuria (BFH) is characterized by autosomal dominant inheritance, thinning of the glomerular basement membrane (GBM) and normal renal function. It is frequent in patients with persistent microscopic hematuria, but cannot be clinically differentiated from the initial stages of Alport syndrome, a severe GBM disorder which progresses to renal failure. We present here linkage of benign familial hematuria with the COL4A3 and COL4A4 genes at 2q35-37 (Zmax = 3.58 at theta = 0.0). Subsequently, a glycine to glutamic acid substitution was identified in the collagenous region of the COL4A4 gene. We conclude that type IV collagen defects cause both benign hematuria and Alport syndrome. Furthermore, our data suggest that BFH patients can be carriers of autosomal recessive Alport syndrome.

c-Myc and Max interactions in quiescent and mitogen-stimulated primary hepatocytes

The c-myc oncogene has been linked with cell proliferation, apoptosis, and differentiation, and when its expression is deregulated also with malignant transformation. In primary hepatocytes c-myc expression is constitutive and in part regulated by hepatocyte-specific growth factors (HGF, TGFalpha, and EGF) in a delayed early response manner. Max expression in these cells was found to be constitutive throughout the in vitro lifetime and mRNA transcript levels were increased at 12 h after induction with growth factors. Max was found to be associated in vivo with hepatocyte Myc species, with this association being independent of growth conditions and of the endogenous Myc or Max levels. Inhibition of endogenous hepatocyte Max levels via expression of an antisense max construct driven by the MMTV promoter did not affect the DNA synthetic response in the presence of dHGF (a variant of HGF). The unusually long half-life of the endogenous Myc species was found to be independent of their association with the widely accepted as "stable" partner, Max. We suggest that Myc and Max in hepatocytes are involved in the growth (proliferation, cell death) and differentiation program of these cells, acting independently or as a complex.

C-myc is required for the G0/G1-S transition of primary hepatocytes stimulated with a deleted form of hepatocyte growth factor

Primary rat hepatocytes stimulated in vitro with the addition of a deleted form of hepatocyte growth factor (dHGF) enter the S-phase 48 h after addition of the growth factor. The c-myc gene is believed to play a role in a variety of cellular stages, such as proliferation, differentiation and cell death. In primary hepatocytes c-myc was expressed constitutively at both mRNA and protein levels, independently of the growth conditions. dHGF induced significant c-myc expression at times correlated with the long-lasting pre-S phase, and no induction was observed at the G0/G1 traverse compared with the unstimulated hepatocytes. An antisense construct coding for all three exons of c-myc was imported into hepatocytes by using the transferrin receptor-mediated endocytosis methodology (transferrinfection). Expression of the antisense construct inhibited the biosynthesis of the c-Myc protein, however it did not interfere with the expression of c-met, encoding the receptor for HGF/dHGF. Continuous expression of the antisense construct inhibited entry of the hepatocytes into the S-phase. Regulated induction of the antisense c-myc by dexamethasone for up to 6 h in culture, did not interfere with the entry of hepatocytes into the S-phase. c-myc expression was shown to be required between 6 and 12 h in dHGF-stimulated hepatocytes, and inhibition of its expression during this time by the antisense myc construct did not allow these cells to enter the S-phase. Inhibition of c-myc biosynthesis between 24 and 48 h hours slightly affected the DNA synthetic response. It is proposed that the expression of c-Myc protein interferes with the "priming' of hepatocytes to become responsive to growth-factor stimuli, or in the absence of such stimuli it interferes with the maintenance of a non-proliferating phenotype and subsequent in vitro de-differentiation.

Localization of hepatitis B virus core protein and viral DNA at the nuclear membrane

An early step in the replication of the hepatitis B virus (HBV) genome is the transport of the viral DNA into the nucleus of the infected cell. So far only little is known about the events and mechanisms at the nuclear membrane required for entry of the viral genome into the nucleus. Using a hepatoblastoma cell line that constitutively produces hepatitis B virions and in so doing displays intracellular viral amplification, we showed that nonparticulated HBV core protein is associated with nuclear membrane pore complexes. Additionally, viral DNA has been detected firmly attached to the nuclear membrane. Small amounts of viral core protein, as well as viral DNA, were detectable within the cell nucleus. However, core particles could not be shown at the nuclear membrane or within the nuclei of these cells. Our observations on localization of HBV DNA and core protein at the nuclear membrane thus provide a suggestion for further examinations of the transfer of the viral genome from the cytoplasm into the nucleus of the infected cell.

The cognitive development of pre-school children treated for chronic renal failure

Chronic renal failure in young children is associated with impaired cognitive development, but recent studies present a more optimistic perspective. An important question is whether the earlier initiation of renal replacement therapy (RRT) might prevent the reported developmental retardation. The cognitive development of 31 patients (age < 5 years with a serum creatinine clearance of < 20% of normal) undergoing different treatment modalities was monitored by repeated measurements during a prospective 3-year study. Fifteen patients received conservative treatment and 16 patients were on dialysis treatment at the start of the project. We were able to evaluate the effect of the onset of RRT on 12 patients who were transferred from conservative treatment to dialysis. At the beginning of the study, the cognitive development of the total group was significantly delayed (mean developmental index = 78.5, SD = 19.5) compared with a normal population. Patients undergoing conservative treatment scored significantly higher (P < 0.01) than those on dialysis. The effect of starting dialysis treatment appeared to be positive, but only a significant short-term improvement was observed. Follow-up evaluation of 7 patients on conservative treatment and of 9 dialysis patients over a 2-year period did not show any significant change in a positive or negative direction. The present study revealed that pre-school dialysis patients are at risk with respect to their cognitive development. This is particularly true for the group with concomitant disorders. Less severe disease in the group on conservative treatment may be assumed to be a positive contributing factor to the more normal performance of these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Renal transplant thrombosis in children

Data concerning 100 consecutive renal transplantations in children were analyzed to determine factors enhancing the risk of renal transplant thrombosis. The incidence of renal transplant thrombosis was high, at 12%. It is concluded that in addition to young age and low body weight of recipient and young age of the donor, also a high preoperative urine production contributes to the occurrence of thrombosis. Children with hypoplastic or dysplastic kidneys are at greater risk for thrombosis. Considering the influence of high urine production of the native kidneys, it may be possible to prevent thrombosis by albumin and ample fluid administration.