Search

Cystinosis is an inherited metabolic disorder caused by recessive mutations in the CTNS gene. The disease primarily affects the kidneys followed by extra-renal organ involvement later in life. Azoospermia is one of the unclarified complications which is not improved by cysteamine treatment, the only available disease-modifying treatment. We aimed at unravelling the origin of azoospermia in cysteamine-treated cystinosis by confirming or excluding an obstructive factor, and investigating the effect of cysteamine on fertility in the Ctns-/- mice model compared to wild-type. Azoospermia was present in the vast majority of infantile type cystinosis patients. While spermatogenesis was intact either at testicular or epididymal level in cystinosis patients, an enlarged caput epididymis and reduced levels of seminal markers for obstruction Neutral α-Glucosidase (NAG) and extracellular matrix protein 1 (ECM1) pointed towards an epididymal obstruction. Transcriptomic analysis of CTNS KD in a fertile human caput epididymal cell line demonstrated upregulation of pathways related to inflammation and cell polarization. Interestingly, histopathological examination in human and mice revealed a disturbed blood-testis barrier (BTB) characterized by an altered zonula occludens-1 (ZO-1) protein expression. Animal studies ruled out a negative effect of cysteamine on fertility, and showed that cystine in the testes is irresponsive to regular cysteamine treatment. We conclude that the azoospermia in infantile cystinosis is due to an obstruction related to epididymal dysfunction, irrespective of the severity of an evolving primary hypogonadism as an additional non-obstructive process. Regular cysteamine treatment does not affect fertility but has subtherapeutic effects on cystine accumulation in testes. This article is protected by copyright. All rights reserved.

Contains fulltext : 234019.pdf (Publisher’s version ) (Open Access) Dopamine beta hydroxylase (DBH) deficiency is an extremely rare autosomal recessive disorder with severe orthostatic hypotension, that can be treated with L-threo-3,4-dihydroxyphenylserine (L-DOPS). We aimed to summarize clinical, biochemical, and genetic data of all world-wide reported patients with DBH-deficiency, and to present detailed new data on long-term follow-up of a relatively large Dutch cohort. We retrospectively describe 10 patients from a Dutch cohort and 15 additional patients from the literature. We identified 25 patients (15 females) from 20 families. Ten patients were diagnosed in the Netherlands. Duration of follow-up of Dutch patients ranged from 1 to 21 years (median 13 years). All patients had severe orthostatic hypotension. Severely decreased or absent (nor)epinephrine, and increased dopamine plasma concentrations were found in 24/25 patients. Impaired kidney function and anemia were present in all Dutch patients, hypomagnesaemia in 5 out of 10. Clinically, all patients responded very well to L-DOPS, with marked reduction of orthostatic complaints. However, orthostatic hypotension remained present, and kidney function, anemia, and hypomagnesaemia only partially improved. Plasma norepinephrine increased and became detectable, while epinephrine remained undetectable in most patients. We confirm the core clinical characteristics of DBH-deficiency and the pathognomonic profile of catecholamines in body fluids. Impaired renal function, anemia, and hypomagnesaemia can be part of the clinical presentation. The subjective response to L-DOPS treatment is excellent and sustained, although the neurotransmitter profile in plasma does not normalize completely. Furthermore, orthostatic hypotension as well as renal function, anemia, and hypomagnesaemia improve only partially.

Item does not contain fulltext

Contains fulltext : 154390.pdf (Publisher’s version ) (Closed access) BACKGROUND: The urinary concentrations of monosaccharides and polyols are used for diagnosing inborn errors of metabolism and renal tubular disorders. Reference values are age-related and depend on the method of detection. However, the influence of the renal function is often still neglected. In this study we examined the urinary excretion of monosaccharides and polyols in children with various degrees of chronic kidney disease (CKD), but with no known metabolic or renal tubular disorders. CASE DIAGNOSIS/TREATMENT: In 25 patients with CKD stage 1-5, urinary concentrations of 18 monosaccharides and polyols were measured by gas chromatography-mass spectrometry (GC-MS) in random urinary samples and were compared with age-related reference values. Serum creatinine was measured at the time of the urine sample, and the height-independent estimated glomerular filtration rate (eGFR-Pottel) was calculated. Urinary excretions of monosaccharides and polyols were above the reference values in 8-88 % of all patients. A significant difference between CKD stage 1-2 compared with CKD stage 3-5 was found for allose, arabitol and sorbitol (p < 0.05) and for arabinose, fucose, myoinositol, ribitol, xylitol, and xylose (p < 0.01). CONCLUSIONS: We show that the excretion of polyols and sugars depends on eGFR, which warrants a cautious interpretation of the results in patients with CKD.

Item does not contain fulltext Magnesium (Mg2+) balance is tightly regulated by the concerted actions of the intestine, bone and kidneys. This balance can be disturbed by a broad variety of drugs. Diuretics, modulators of the EGFR (epidermal growth factor receptor), proton pump inhibitors, antimicrobials, calcineurin inhibitors and cytostatics may all cause hypomagnesaemia, potentially leading to tetany, seizures and cardiac arrhythmias. Conversely, high doses of Mg2+ salts, frequently administered as an antacid or a laxative, may lead to hypermagnesaemia causing various cardiovascular and neuromuscular abnormalities. A better understanding of the molecular mechanisms underlying the adverse effects of these medications on Mg2+ balance will indicate ways of prevention and treatment of these adverse effects and could potentially provide more insight into Mg2+ homoeostasis. 01 juli 2012

Contains fulltext : 174488.pdf (Publisher’s version ) (Open Access) 01 juli 2017

Contains fulltext : 95780.pdf (Publisher’s version ) (Closed access) Recent evidence implies that impaired metabolism of glutathione has a role in the pathogenesis of nephropathic cystinosis. This recessive inherited disorder is characterized by lysosomal cystine accumulation and results in renal Fanconi syndrome progressing to end stage renal disease in the majority of patients. The most common treatment involves intracellular cystine depletion by cysteamine, delaying the development of end stage renal disease by a yet elusive mechanism. However, cystine depletion does not arrest the disease nor cures Fanconi syndrome in patients, indicating involvement of other yet unknown pathologic pathways. Using a newly developed proximal tubular epithelial cell model from cystinotic patients, we investigate the effect of cystine accumulation and cysteamine on both glutathione and ATP metabolism. In addition to the expected increase in cystine and defective sodium-dependent phosphate reabsorption, we observed less negative glutathione redox status and decreased intracellular ATP levels. No differences between control and cystinosis cell lines were observed with respect to protein turnover, albumin uptake, cytosolic and mitochondrial ATP production, total glutathione levels, protein oxidation and lipid peroxidation. Cysteamine treatment increased total glutathione in both control and cystinotic cells and normalized cystine levels and glutathione redox status in cystinotic cells. However, cysteamine did not improve decreased sodium-dependent phosphate uptake. Our data implicate that cysteamine increases total glutathione and restores glutathione redox status in cystinosis, which is a positive side-effect of this agent next to cystine depletion. This beneficial effect points to a potential role of cysteamine as anti-oxidant for other renal disorders associated with enhanced oxidative stress.

Item does not contain fulltext This is the first report that presents renal transplantation after bilateral nephrectomy as the final treatment for severe renovascular hypertension due to fibromuscular dysplasia (FMD). We describe the history of a 1-year-old girl who suffered from renovascular hypertension due to FMD. Imaging revealed multiple bilateral stenoses of the renal artery extending into the distal branches. The hypertension proved unresponsive to pharmacologic treatment and the intrarenal peripherally located stenoses rendered a conventional approach such as transluminal or surgical angioplasty not feasible. At the age of 5 years, a unilateral nephrectomy of the most affected kidney was performed, but she remained hypertensive and developed progressive cardiomyopathy and retinopathy. At the age of 6 years the remaining kidney was removed, followed by a living related renal transplantation with a kidney donated by her mother. Posttransplantation, she developed mild hypertension due to a postanastomotic stenosis, which was easily controlled with antihypertensives. Now 8 years after transplantation, she has experienced no further blood pressure related problems. Although there is a risk of recurrence of FMD after performing a living related transplantation, our report suggests that this procedure is relatively safe, provided appropriate preoperative evaluation and follow up is performed.

Item does not contain fulltext BACKGROUND AND OBJECTIVES: Mutations in podocyte genes are associated with steroid-resistant nephrotic syndrome (SRNS), mostly affecting younger age groups. To date, it is unclear whether these patients benefit from intensified immunosuppression with cyclosporine A (CsA). The aim of this study was to evaluate the influence of podocyte gene defects in congenital nephrotic syndrome (CNS) and pediatric SRNS on the efficacy of CsA therapy and preservation of renal function. Design, settings, participants, & measurements: Genotyping was performed in 91 CNS/SRNS patients, irrespective of age at manifestation or response to CsA. RESULTS: Mutations were identified in 52% of families (11 NPHS1, 17 NPHS2, 11 WT1, 1 LAMB2, 3 TRPC6). Sixty-eight percent of patients with nongenetic SRNS responded to CsA, most of them achieved complete remission. In contrast, none of the patients with genetic CNS/SRNS experienced a complete remission and only two (17%) achieved a partial response, both affected by a WT1 mutation. Preservation of renal function was significantly better in children with nongenetic disease after a mean follow-up time of 8.6 years (ESRD in 29% versus 71%). CONCLUSIONS: The mutation detection rate in our population was high (52%). Most patients with genetic CNS/SRNS did not benefit from CsA with significantly lower response rates compared with nongenetic patients and showed rapid progression to end-stage renal failure. These data strongly support the idea not to expose CNS/SRNS patients with inherited defects related to podocyte function to intensified immunosuppression with CsA. 01 november 2010

Contains fulltext : 89524.pdf (Publisher’s version ) (Closed access) The nephrogenic syndrome of inappropriate antidiuresis (NSIAD) is a rare, recently recognized disorder in water balance affecting not only infants but also adults. A new molecular mechanism responsible for NSIAD has recently been identified: a gain of function of the arginine vasopressin (AVP) receptor type 2 (V2R), causing the constitutive activation of the receptor. Clinical presentation and laboratory findings of NSIAD resemble those of the syndrome of inappropriate secretion of antidiuretic hormone and consist of hyponatraemia, seizures and the lack of urinary dilution; however, the AVP levels in plasma are undetectable or very low. An elucidation of the pathophysiology of this syndrome will provide more insight into the action of AVP. An effective treatment of NSIAD is available. It consists of fluid restriction and administration of oral urea. Reported experience with furosemide treatment in NSIAD is still lacking. 01 september 2010

This review deals with podocyte proteins that play a significant role in the structure and function of the glomerular filter. Genetic linkage studies has identified several genes involved in the development of nephrotic syndrome and contributed to the understanding of the pathophysiology of glomerular proteinuria and/or focal segmental glomerulosclerosis. Here, we describe already well-characterized genetic diseases due to mutations in nephrin, podocin, CD2AP, alpha-actinin-4, WT1, and laminin beta2 chain, as well as more recently identified genetic abnormalities in TRPC6, phospholipase C epsilon, and the proteins encoded by the mitochondrial genome. In addition, the role of the proteins which have shown to be important for the structure and functions by gene knockout studies in mice, are also discussed. Furthermore, some rare syndromes with glomerular involvement, in which molecular defects have been recently identified, are briefly described. In summary, this review updates the current knowledge of genetic causes of congenital and childhood nephrotic syndrome and provides new insights into mechanisms of glomerular dysfunction. ispartof: European Journal of Pediatrics vol:168 issue:11 pages:1291-1304 ispartof: location:Germany status: published

A familial autosomal recessive form of isolated renal magnesium loss is presented. Two children in this family suffered from convulsions unrelated to hypomagnesemia. Magnesium infusion studies revealed a lowered threshold but a normal tubular maximum for magnesium. In contrast to two families with the autosomal dominant form of isolated renal magnesium wasting, the calcium excretion in the urine was normal.

An unusual form of galactosemia is described in a 7-month-old boy, characterized by a late onset of the clinical symptoms. A high apparent residual activity of erythrocyte galactose-1-phosphate uridyl transferase (GT) was measured with the spectrophotometric UDP-Glucose consumption test (±25% of normal). The residual activity in erythrocyte lysates, determined when the patient was 7, 16 and 22 months old, significantly decreased upon storage and after preincubation with NAD-ase. The radiochemical measurement of GT activity demonstrated a severe deficiency: only a level of ± 1% of normal activity was observed, and no effects of storage or NAD-ase could be demonstrated. GT and galactokinase (GK) activities were measured radiochemically in lysates from hair roots obtained from the human scalp, and it was found that the GT/GK activity ratio is a useful index for the detection of heterozygotes. Erythrocyte and hair root lysates from the heterozygous parents of the patient displayed GT/GK ratios which were intermediate between mutant and normal. Because they offer a simple and fast way to obtain biopsy material, hair roots might become of increasing importance for carrier detection studies.

Contains fulltext : 51758.pdf (Publisher’s version ) (Open Access) BACKGROUND: Minimal change nephrotic syndrome (MCNS) is the most frequent form of nephrotic syndrome in childhood. In the glomerular basement membrane (GBM) of adult patients with MCNS, a reduced expression of a specific heparan sulphate (HS) domain has been reported. In children with MCNS, urinary activity of the HS-degrading enzyme heparanase was increased. It is, therefore, possible that a decreased GBM HS expression is associated with the pathogenesis of proteinuria in patients with MCNS. METHODS: In this study, HS in glomeruli of five adult and six paediatric patients with MCNS were analysed by immunofluorescence staining using four different antibodies, each defining a specific sulphated HS domain. The pediatric patients were subdivided into three groups depending on the presence or absence of podocyte foot process effacement, the level of proteinuria and prednisone administration at the time of the biopsy. In addition, kidneys of rats with adriamycin nephropathy (ADRN), a model for MCNS, were included in the study. RESULTS: Expression of sulphated HS domains was not aberrant in adult or paediatric patients compared with control subjects. Children with and without proteinuria had the same HS content. In contrast, rats with ADRN showed a decreased glomerular expression of sulphated HS domains. CONCLUSIONS: These results suggest that in patients with MCNS proteinuria is not associated with major changes in glomerular expression of sulphated HS domains.

Contains fulltext : 52538.pdf (Publisher’s version ) (Closed access) The ability of cystine dimethylester (CDME) to load lysosomes with cystine has been used to establish the basic defect in cystinosis: defective cystine exodus from lysosomes. Using CDME loading, it has been postulated that cystine accumulation in cystinosis affects mitochondrial ATP production, resulting in defective renal tubular reabsorption. Recent studies in cystinotic fibroblasts, however, show normal adenosine triphosphate (ATP) generation capacity. To investigate the effect of CDME in more detail, mitochondrial ATP generation, reactive oxygen species production, and viability are compared in fibroblasts loaded with CDME with those of cystinotic cells with a defective cystine transporter. Intracellular cystine levels were comparable in fibroblasts loaded with CDME (1 mM, 30 min) and cystinotic fibroblasts. Intracellular ATP levels and mitochondrial ATP production were decreased in fibroblasts loaded with CDME, but normal in cystinotic fibroblasts. Superoxide production was increased with 300% after CDME loading, whereas no changes were observed in cystinotic fibroblasts. Exposure to CDME led to cell death in a time- and concentration-dependent manner. Our data demonstrate that CDME has a toxic effect on mitochondrial ATP production and cell viability. These effects are not observed in cystinotic cells, indicating that a more appropriate model is required for studying the pathogenesis of cystinosis.

Contains fulltext : 51416.pdf (Publisher’s version ) (Closed access) BACKGROUND: After gastrointestinal infection with Shiga-like toxin (Stx) producing Escherichia coli, the toxin is transported from the intestine to the renal microvascular endothelium. This is the main target for Stx in humans. Previous studies indicated that polymorphonuclear leucocytes (PMN) could serve as carriers for Stx in the systemic circulation. As at a later stage we could not confirm these data, we performed new studies. METHODS: The binding of Stx1 to PMN was determined in vitro (isolated human PMN and whole blood) and in vivo (injection in mice). The specificity of binding of an antibody against Stx2 to PMN from patients with haemolytic uraemic syndrome (HUS) was determined. This was compared with binding to PMN from healthy controls, and patients after haemodialysis (HD) or on peritoneal dialysis (PD). Furthermore, PMN were incubated with Stx to study possible activation. RESULTS: No specific binding of Stx1 to PMN could be detected. After intravenous injection of the toxin in mice, it was not associated with PMN. The binding of an antibody against Stx2 to PMN was detected in both patients with HUS and patients after HD, but not in patients on PD. Stx was not able to activate PMN. CONCLUSIONS: PMN are not acting as transporter for Stx in the pathogenesis of HUS. The interaction of a Stx antibody with PMN from HUS patients is not specific as it can also be observed in patients after HD (possibly due to activation of the PMN). Therefore, binding of Stx antibody to PMN is not reliable as a diagnostic tool for HUS.

Contains fulltext : 53032.pdf (Publisher’s version ) (Open Access) Heparan sulfates (HS) are long, unbranched, negatively charged polysaccharides that are bound to core proteins. HS in the glomerular basement membrane (GBM) is reported to be important for charge-selective permeability. Aberrant GBM HS expression has been observed in several glomerular diseases, such as diabetic nephropathy and membranous glomerulopathy, and a decrease in HS generally is associated with proteinuria. This study, with the use of a controlled in vivo approach, evaluated whether degradation of HS in rat GBM resulted in acute proteinuria. Rats received two intravenous injections of either heparinase III to digest HS or neuraminidase to remove neuraminic acids (positive control). Urine samples were taken at various time points, and at the end of the experiment, kidneys were removed and analyzed. Injection with heparinase III resulted in a complete loss of glomerular HS as demonstrated by immunofluorescence staining using anti-HS antibodies and by electron microscopy using cupromeronic blue in a critical electrolyte concentration mode. In the urine, a strong increase in HS was found within 2 h after the first injection. Staining for agrin, the major HS proteoglycan core protein in the GBM, was unaltered. No urinary albumin or other proteins were detected at any time point, and no changes in glomerular morphology were noticed. Injection of rats with neuraminidase, however, resulted in a major increase of urinary albumin and was associated with an increase in urinary free neuraminic acid. An increased glomerular staining with Peanut agglutinin lectin, indicative of removal of neuraminic acid, was noted. In conclusion, removal of HS from the GBM does not result in acute albuminuria, whereas removal of neuraminic acid does.

Item does not contain fulltext Focal segmental glomerulosclerosis (FSGS) is a histologic diagnosis in several kidney diseases characterized by proteinuria and a severe decrease in kidney function. Mutations in several genes were found in patients with primary FSGS, one of which is a CD2-associated protein CD2AP (originally referred to as CMS). This gene encodes an adaptor protein that plays a role in endocytosis, cell motility, and cell survival. Mice deficient in Cd2ap (the mouse homolog) die due to kidney failure, while heterozygous mice develop lesions similar to those of FSGS patients. In the kidney, CD2AP regulates the actin cytoskeleton. The only previously described patient with CD2AP mutation had a severely truncated protein. In this study, we describe a patient with a novel mutation resulting in a premature stop codon yielding a protein truncated by only 4%. This shortened CD2AP protein displays a significantly decreased F-actin binding efficiency in vitro with no expression of the mutated allele in the patient's lymphocytes. Heterozygous expression of the CD2AP mutation in both parents did not lead to any kidney pathology, as both have normal glomerular filtration rates and no proteinuria.

Calcium (Ca2+) and magnesium (Mg2+) ions are involved in many vital physiological functions. Since dietary intake is the only source of minerals for the body, intestinal absorption is essential for normal homeostatic levels. The aim of this study was to characterize the absorption of Ca2+as well as Mg2+along the gastrointestinal tract at a molecular and functional level. In both humans and mice the Ca2+channel transient receptor potential vanilloid subtype 6 (TRPV6) is expressed in the proximal intestinal segments, whereas Mg2+channel transient receptor potential melastatin subtype 6 (TRPM6) is expressed in the distal parts of the intestine. A method was established to measure the rate of Mg2+absorption from the intestine in a time-dependent manner by use of25Mg2+. In addition, local absorption of Ca2+and Mg2+in different segments of the intestine of mice was determined by using surgically implanted intestinal cannulas. By these methods, it was demonstrated that intestinal absorption of Mg2+is regulated by dietary needs in a vitamin D-independent manner. Also, it was shown that at low luminal concentrations, favoring transcellular absorption, Ca2+transport mainly takes place in the proximal segments of the intestine, whereas Mg2+absorption predominantly occurs in the distal part of the gastrointestinal tract. Vitamin D treatment of mice increased serum Mg2+levels and 24-h urinary Mg2+excretion, but not intestinal absorption of25Mg2+. Segmental cannulation of the intestine and time-dependent absorption studies using25Mg2+provide new ways to study intestinal Mg2+absorption.

Item does not contain fulltext This study has determined the intracellular transport route of Shiga-like toxin (Stx) and the highly related Shiga toxin in human glomerular microvascular endothelial cells (GMVECs) and mesangial cells. In addition, the effect of tumor necrosis factor-alpha (TNF-alpha), which contributes to the pathogenesis of hemolytic-uremic syndrome, was evaluated more profound. Establishing the transport route will provide better understanding of the cytotoxic effect of Stx on renal cells. For our studies, we used receptor-binding B-subunit (StxB), which is identical between Shiga toxin and Stx-1. The transport route of StxB was studied by immunofluorescence microscopy and biochemical assays that allow quantitative analysis of retrograde transport from plasma membrane to Golgi apparatus and endoplasmic reticulum (ER). In both cell types, StxB was detergent-resistant membrane associated and followed the retrograde route. TNF-alpha upregulated Gb3 expression in mesangial cells and GMVECs, without affecting the efficiency of StxB transport to the ER. In conclusion, our study shows that in human GMVECs and mesangial cells, StxB follows the retrograde route to the Golgi apparatus and the ER. TNF-alpha treatment increases the amount of cell-associated StxB, but not retrograde transport as such, making it likely that the strong TNF-alpha-induced sensitization of mesangial cells and GMVECs for the toxic action of Stx is not due to a direct effect on the intracellular trafficking of the toxin.Kidney International (2006) 70, 2085-2091. doi:10.1038/sj.ki.5001989; published online 25 October 2006.

Contains fulltext : 49692.pdf (Publisher’s version ) (Closed access) Cystinosis is an autosomal recessive disorder, caused by mutations in the lysosomal cystine carrier cystinosin, encoded by the CTNS gene. The disease generally manifests with Fanconi syndrome during the first year of life and progresses towards end stage renal disease before the age of 10 years. Cysteamine depletes intralysosomal cystine content, postpones the deterioration of renal function and the occurrence of extra-renal organ damage. Based on the pharmacokinetic data, patients with cystinosis are advised to use cysteamine every 6 h. The aim of this study was (1) to evaluate the cysteamine dose regimen in Dutch patients with cystinosis and (2) to determine morning polymorphonuclear (PMN) leukocyte cystine content 6 h vs 9 h after the last evening cysteamine dose. Only 5/22 of Dutch cystinosis patients ingested cysteamine every 6 h. Morning (8 a.m.) PMN cystine content in 11 examined patients was elevated 9 h after 12.5-15 mg/kg evening cysteamine dose compared to the value 6 h after the ingestion of the same dose (0.73+/-0.81 nmol vs 0.44+/-0.52 nmol cystine/mg protein, p =0.02). In conclusion, only the minority of Dutch cystinosis patients follows the recommended strict cysteamine dose regimen. We provide evidence that cysteamine has to be administered every 6 h, including the night, as it has much better effect for maintaining low PMN cystine levels.

ObjectivesTo establish intraperitoneal pressure (IPP) in a relatively large pediatric study group and to study the effects of a 3.86% glucose solution and a 7.5% icodextrin solution on IPP during a 4-hour dwell.DesignIPP was measured with the patient in a supine position. The intraperitoneal volume (IPV) was 1200 mL/m2with a 1.36% glucose solution. The influence of dialysis solutions was obtained by performing two 4-hour peritoneal equilibration tests (PETs) with 3.86% glucose and 7.5% icodextrin as test solution, using an IPV of 1200 mL/m2and dextran 70 as volume marker. IPP was measured at two consecutive time points ( t = 0 and t = 240 minutes). Transcapillary ultrafiltration, net ultrafiltration, and marker clearance were calculated.PatientsIPP was established in 30 patients with median age of 4.5 years (range 1.0 – 14.9 years). Influence of dialysis solutions on IPP was studied in 9 children with median age of 4.2 years (range 1.7 – 10.9 years) and median treatment period of 12 months (range 5.6 – 122.3 months).ResultsMean IPP was 12.0 ± 6.5 cm H2O. Significant relations were found between the change in IPP and transcapillary ultrafiltration and body surface area during the PET with 3.86% glucose. No relations were seen during the PET with icodextrin.ConclusionsIPP was established in a large pediatric study group and was similar to previously published values of IPP in a small number of patients. Differences in fluid kinetics have different effects on the change in IPP during a 4-hour dwell period.

Item does not contain fulltext Scarce data are available on the use of glucose polymer-based dialysate in children. The effects of glucose polymer-based dialysate on peritoneal fluid kinetics and solute transport were studied in pediatric patients who were on chronic peritoneal dialysis, and a comparison was made with previously published results in adult patients. In nine children, two peritoneal equilibration tests were performed using 3.86% glucose and 7.5% icodextrin as a test solution. Dextran 70 was added as a volume marker to calculate fluid kinetics. Serum and dialysate samples were taken for determination of urea, creatinine, and sodium. After calculation of the initial transcapillary ultrafiltration (TCUF) rate, it was possible to calculate the contribution of aquaporin-mediated (AQP-mediated) water transport to ultrafiltration for icodextrin and 3.86% glucose and the part of L(p)S (the product of the peritoneal surface area and the hydraulic permeability) caused by AQP. In children, the transport parameters were similar for the two solutions, except for TCUF, which was lower for icodextrin (0.9 ml/min per 1.73 m(2)) as compared with 3.86% glucose (4 ml/min per 1.73 m(2)). Transport parameters were similar in children and adults for glucose, but with icodextrin, TCUF and marker clearance were significantly lower in children. AQP-mediated water flow was 83 versus 50% with glucose (child versus adult; P < 0.01) and 18 versus 7% with icodextrin (P < 0.01). Data indicate that transport parameters in children using icodextrin are similar to glucose except for TCUF. Differences are explained by the absence of crystalloid osmosis and that TCUF was determined after a 4-h dwell. Comparison of transport parameters and peritoneal membrane characteristics between children and adults reveal that there seem to be differences in the amount and functionality of AQP. However, there are no differences in clinical efficacy of this transport pathway because the absolute flow through the AQP is identical in both groups using 3.86% glucose.

Contains fulltext : 58356.pdf (Publisher’s version ) (Closed access) Inner ear physiology is reviewed with emphasis on features common to renal physiology. Genetic disorders in transporters/channels for chloride (ClC-K), bicarbonate (Cl(-)/HCO(3)(-) exchanger), protons (H(+)-ATPase), sodium (ENaC, NKKC1, NBC3, NHE3), potassium (KCNQ1/KCNE1, Kcc4), and water (AQP4) in the inner ear and their relation to the kidney are discussed. Based on data from human disorders (with or without mouse counterparts) and mouse models (without human counterparts) this article focuses on the involvement of these transporters/channels in hearing loss.

BACKGROUND: The reported outcome of renal transplantation in patients with the hemolytic uremic syndrome (HUS) varies greatly, probably related to the diverse causes of HUS. In this single-center retrospective study, we have analyzed the recurrence rate, the incidence of acute rejections, and graft survival in patients suffering from adult-onset and childhood-onset HUS. METHODS: The medical records of 35 patients with end-stage renal disease caused by HUS, who received 50 renal allografts, were reviewed. A definite recurrence of HUS was diagnosed if both clinical and histologic signs of thrombotic microangiopathy (TMA) were present in the absence of any endovasculitis. If there were signs of mild endovasculitis, a probable recurrence was diagnosed. RESULTS: After first renal transplantation, 0 definite and 1 (6%) probable recurrence occurred in 18 patients with childhood-onset HUS, as opposed to 7 (41%) definite and 3 (18%) probable recurrences in 17 adult-onset HUS patients (odds ratio [OR], 13.4; 95% confidence interval [CI], 1.7-105.7). In the latter patients, early use of cyclosporine A increased the risk for recurrence. The incidence of acute rejections was increased compared with matched controls (OR, 1.52; 95% CI, 1.05-2.19 for adult-onset HUS and OR, 1.88; 95% CI, 1.34-2.62 for childhood-onset HUS). One-year graft survival in adult-onset HUS was poor (29%), whereas 1-year graft survival in childhood-onset HUS was comparable to matched controls. CONCLUSIONS: In adult-onset HUS, the recurrence rate and the incidence of acute rejections are high, resulting in a detrimental graft survival. In childhood-onset HUS, the recurrence rate is low, but the posttransplantation course is complicated by an increased incidence of acute rejections.

BACKGROUND: Based on genetic studies in families with hereditary renal Mg(2+) reabsorption disorders, several genes were shown to be involved in renal Mg(2+) transport. Mutations in the CLDN16 gene were found to underlie autosomal recessive hypomagnesaemia associated with hypercalciuria and nephrocalcinosis. The FXYD2 gene was implicated in autosomal dominant renal Mg(2+) wasting associated with hypocalciuria. Mutations in the SLC12A3 gene, also known as NCC, cause Gitelman's syndrome. In addition to hypokalaemic metabolic alkalosis, hypomagnesaemia associated with hypocalciuria is considered to be a hallmark feature of this latter disorder. METHODS: We have characterized a new family with presumed dominant renal hypomagnesaemia by detailed clinical examination and mutation analysis of CLDN16, FXYD2 and SLC12A3. In addition, we have performed mutation analysis of these three genes in a previously described family with autosomal recessive renal Mg(2+) wasting. In this family, linkage analysis was performed with polymorphic markers in the vicinity of the FXYD2 gene. RESULTS: The phenotype of the new family closely resembles that of the known dominant families with a mutation in FXYD2, but mutations in this gene were not identified in the new family. No mutations were found in CLDN16 and SLC12A3 either. Sequencing of the three genes in the patients of the recessive family revealed no mutations. In addition, haplotype analysis excluded linkage to the FXYD2 region on chromosome 11q23. CONCLUSION: Our results indicate that, in addition to the currently known loci involved in renal Mg(2+) handling, at least one other gene must be involved.

Item does not contain fulltext Hereditary primary hypomagnesemia comprises a clinically and genetically heterogeneous group of disorders in which hypomagnesemia is due to either renal or intestinal Mg(2+) wasting. These disorders share the general symptoms of hypomagnesemia, tetany and epileptiformic convulsions, and often include secondary or associated disturbances in calcium excretion. In a large Dutch family with autosomal dominant renal hypomagnesemia, associated with hypocalciuria, we mapped the disease locus to a 5.6-cM region on chromosome 11q23. After candidate screening, we identified a heterozygous mutation in the FXYD2 gene, encoding the Na(+),K(+)-ATPase gamma-subunit, cosegregating with the patients of this family, which was not found in 132 control chromosomes. The mutation leads to a G41R substitution, introducing a charged amino acid residue in the predicted transmembrane region of the gamma-subunit protein. Expression studies in insect Sf9 and COS-1 cells showed that the mutant gamma-subunit protein was incorrectly routed and accumulated in perinuclear structures. In addition to disturbed routing of the G41R mutant, Western blot analysis of Xenopus oocytes expressing wild-type or mutant gamma-subunit showed mutant gamma-subunit lacking a posttranslational modification. Finally, we investigated two individuals lacking one copy of the FXYD2 gene and found their serum Mg(2+) levels to be within the normal range. We conclude that the arrest of mutant gamma-subunit in distinct intracellular structures is associated with aberrant posttranslational processing and that the G41R mutation causes dominant renal hypomagnesemia associated with hypocalciuria through a dominant negative mechanism.

Background: It has been suggested that serum cystatin C (cyst-C) concentration provides a better indication of changes in glomerular filtration rate (GFR) than does serum creatinine concentration. Methods: Because of conflicting results as to the usefulness of cyst-C, we compared the GFRs calculated from serum cyst-C, inulin clearance and endogenous creatinine clearance in children. GFRs calculated from cystatin concentration, inulin clearance following a single injection and endogenous creatinine clearance using Jaffé and enzymic methods were compared in 66 children (1·3-21·9 years) with a variety of renal disorders. Receiver operating curve analysis was used to determine the cut-off value that would give the best discrimination between normal and decreased GFR. Results: The serum cyst-C concentration ranged from 0·66 to 7·61 mg/L (median 1·94). Serum creatinine Jaffé concentration (creat-J) ranged from 38 to 871 µmol/L (median 105) and creatinine enzymatic concentration (creat-E) ranged from 28 to 862 µmol/L (median 126). The linear correlation coefficient ( R) of 1/cyst-C versus GFR ( R = 0·937) did not differ from either that of 1/creat-J versus GFR ( R = 0·918) or that of 1/creat-E versus GFR ( R = 0·901). These coefficients had overlapping confidence intervals. The areas under the curve for cyst-C, creat-J and creat-E were 0·967, 0·977 and 0·924, respectively, and were not significantly different from each other. For cyst-C, the optimal cut-off was 1·1 mg/L. Conclusions: Serum cyst-C is equivalent to creat-J and creat-E as a marker for estimating the GFR in the paediatric population studied.

Mutation analysis and clinical implications of von Willebrand factor–cleaving protease deficiency.BackgroundThe pentad of thrombocytopenia, hemolytic anemia, mild renal dysfunction, neurologic signs, and fever, classically characterizes the syndrome of thrombotic thrombocytopenic purpura (TTP). TTP usually occurs in adults as an acquired form but a congenital form in children has also been described. In the latter case, the initial presentation is often with neonatal jaundice and thrombocytopenia. The disorder may subsequently take a relapsing course. Deficiency of a recently identified novel metalloprotease, the von Willebrand factor (vWF)–cleaving protease, originating from mutations in the ADAMTS13 gene plays a major role in the development of TTP.MethodsBlood for DNA analysis was collected from six unrelated TTP families, consisting of nine patients from four different countries, and was screened for mutations in the ADAMTS 13 gene. This gene spans 29 exons encompassing ∼37kb. Conventional techniques of DNA extraction, polymerase chain reaction (PCR), and direct cycle sequencing were used.ResultsEight novel ADAMTS 13 mutations are presented. Half of the total number of mutant ADAMTS13 alleles are amino acid substitutions. The disease-causing mutations are spread over the gene. The pathogenicity of the individual mutations is based upon their predicted effect on the ADAMTS13 protein and segregation in family members. Although most of the patients (seven out of nine) had symptoms during the neonatal period, they were in a remarkably good condition. Only one of the nine patients had a decreased glomerular filtration rate (GFR) with proteinuria and hematuria. Another patient had epileptic seizures.ConclusionWe confirm that deficiency of ADAMTS13 is a molecular mechanism responsible for familial TTP. An early diagnosis allows prophylactic treatment with fresh plasma infusions.

Item does not contain fulltext Type I pseudohypoaldosteronism (PHA-1) is a rare salt wasting syndrome occurring soon after birth, characterized by apathy and severe dehydration accompanied by hyponatremia, hyperkalemia, and metabolic acidosis despite high plasma aldosterone concentrations. The molecular defect involved in the systemic autosomal recessive form of the syndrome has been identified. Mutations in all three genes encoding the epithelial sodium channel (ENaC) lead to a decrease in the channel function, resulting in the disease. We report here two new cases of the autosomal recessive form of PHA-1 in the same family. We found a new homozygous mutation of the gene encoding the alpha ENaC subunit (alphaR492stop). The function of the mutated ENaC channel was assessed in the Xenopus laevis oocyte expression system. The mutant ENaC activity measured with the two-electrode voltage clamp method was drastically decreased compared with the wild type activity, in agreement with the salt-losing phenotype.

Shiga toxin-2 triggers endothelial leukocyte adhesion and transmigration via NF-κB dependent up-regulation of IL-8 and MCP-1. Background Shiga toxin (Stx)-producing E. coli is a causative agent of the epidemic form of hemolytic uremic syndrome (HUS), the most common cause of acute renal failure in children. Endothelial injury and leukocyte activation are instrumental to the development of microangiopathic lesions. To obtain more insight into the mechanisms favoring endothelium-leukocyte interaction, we studied ( 1 ) the effect of Stx-2 on leukocyte adhesion and transmigration in human endothelial cells under flow; ( 2 ) the effect of Stx-2 on endothelial expression of monocyte chemoattractant protein-1 (MCP-1) and interleukin-8 (IL-8) and their functional role in the adhesive phenomena; and ( 3 ) the role of nuclear factor-κB (NF-κB) in endothelial chemokine expression. Methods For adhesion experiments, human umbilical vein endothelial cells (HUVEC) and human glomerular endothelial cells (GEC) were incubated for 24 hours with Stx-2 (25 pmol/L), with or without anti-IL-8 or MCP-1 antibodies, and then exposed to leukocyte suspension under flow (1.5 dynes/cm 2 ). IL-8 and MCP-1 expression was evaluated in Stx-2 treated endothelial cells (6 hours) by Northern blot. NF-κB activity was assessed by electrophoretic mobility shift assay. The role of NF-κB in Stx-induced chemokines was evaluated by transfecting HUVEC with an adenovirus coding for IκBα. Results Stx-2 significantly enhanced the number of leukocytes that adhered and then migrated across the endothelium. Stx-2 increased the expression of IL-8 and MCP-1, which was preceded by NF-κB activation. Blocking of endothelial IL-8 and MCP-1 with corresponding antibodies significantly inhibited Stx-induced leukocyte adhesion and migration either in HUVEC or GEC. Adenovirus-mediated gene transfer of IκBα down-regulated IL-8 and MCP-1 mRNA and also inhibited the adhesion and transmigration of leukocytes in Stx-treated HUVEC. Conclusions Stx-2 via a transcriptional activation mechanism specifically mediated by NF-κB up-regulates endothelial MCP-1 and IL-8. Both chemokines are important modulators of leukocyte adhesion and transmigration under flow. These findings might be relevant to understand the nature of microvascular lesions in HUS and open future perspectives for better treatment of microvascular thrombosis.

Hypoglycosylation of glycoproteins is characteristic for congenital disorders of glycosylation (CDG) and may consist of partial or completely missing glycans (1). The major first test for CDG is isoelectric focusing (IEF) of plasma transferrin. The IEF pattern shows a cathodal shift because of the hypoglycosylation of the protein (2). Primary defects in the N-glycan biosynthetic pathway are known for nine CDG subtypes: CDG Ia–f and CDG IIa–c (3)(4)(5)(6)(7)(8). Transferrin hypoglycosylation can also be secondary to chronic alcohol abuse (9)(10), galactosemia (11), hereditary fructose intolerance (12), and severe liver pathology (9). In this report we describe the association of a transient abnormal transferrin N-glycosylation pattern in plasma and the clinical forms of hemolytic uremic syndrome (HUS) (13)(14)(15) associated with a Streptococcus pneumoniae infection (16). Five patients with HUS associated with a S. pneumoniae infection (age range, 9 months to 2 years) were studied. They fulfilled the criteria for HUS [hemolytic anemia with microangiopathic changes on peripheral blood smear (Burr cells), acute renal failure, and thrombocytopenia] and presented with pneumonia or meningitis. S. pneumoniae was isolated from body fluids of the five patients. We also studied three patients with HUS attributable to verocytotoxin-producing Escherichia coli (VTEC) infection and one case of familial HUS of unknown etiology. von Willebrand factor cleaving protease deficiency and a defect in factor H were excluded in this patient. The sialotransferrin fractions for the five S. pneumoniae -associated HUS cases and healthy controls are shown in Table 1⇓ and Fig. 1⇓ . In healthy individuals (Fig. 1A⇓ , lane 1), the major transferrin form is the tetrasialo form. In all HUS cases associated with S. pneumoniae , the tetrasialotransferrin fraction was markedly decreased and the a-, mono-, and …

Item does not contain fulltext To obtain information on water and salt regulating hormones and volume homeostasis during neonatal extracorporeal membrane oxygenation (ECMO), serial determinations of atrial natriuretic peptide (ANP), plasma renin activity (PRA), aldosterone (Aldo), antidiuretic hormone (ADH), colloid-osmotic pressure (COP), osmolality (Osmol), and central venous pressure (CVP) before, during, and after neonatal ECMO in 10 neonates with meconium aspiration syndrome (MAS) were carried out. Mean gestational ages and birth weights were 41(+3) weeks (39(+6) - 42(+4)) and 4,063 gm (3,500-4700), respectively; mean age at start and duration of ECMO 29.3 (14-69) and 152.6 hr (92-267), respectively. Plasma ANP (mean +/- SD) was 67.8+/-69.1 pmol/L before, decreased to 33.3+/-22.1 (not significant) pmol/L during, and significantly increased to 274.6+/-131.8 pmol/L after ECMO (p < 0.05). ANP correlated positively with CVP (r = 0.63; p < 0.001). Pre-ECMO PRA, Aldo, and ADH were comparable to those described earlier in normal neonates, decreased during (p < 0.001 for Aldo; p < 0.05 for PRA and ADH) and either remained elevated (PRA, p < 0.001; Aldo, p < 0.05) or decreased (ADH) after ECMO. COP and Osmol remained unchanged. Neonatal ECMO for MAS is characterized by circulatory and osmotic equilibrium. It is suggested that circulating volume contracts during and expands after neonatal ECMO for MAS.

ObjectiveTo evaluate the use of the combination of cefazolin and ceftazidime for initial treatment of peritoneal dialysis (PD)-related peritonitis in pediatric patients.DesignRetrospective nonrandomized study.SettingPediatric dialysis units of the University Medical Center of Utrecht and Nijmegen, The Netherlands.Patients40 children (median age 5.4 years) who were treated with PD during the study period of 4.5 years.InterventionsAll 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.ResultsAfter 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.ConclusionsThe 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.

The pathogenesis of the epidemic form of hemolytic uremic syndrome is characterized by endothelial cell damage. In this study, the role of apoptosis in verocytotoxin (VT)-mediated endothelial cell death in human glomerular microvascular endothelial cells (GMVEC), human umbilical vein endothelial cells, and foreskin microvascular endothelial cells (FMVEC) was investigated. VT induced apoptosis in GMVEC and human umbilical vein endothelial cells when the cells were prestimulated with the inflammatory mediator tumor necrosis factor-alpha (TNF-alpha). FMVEC displayed strong binding of VT and high susceptibility to VT under basal conditions, which made them suitable for the study of VT-induced apoptosis without TNF-alpha interference. On the basis of functional (flow cytometry and immunofluorescence microscopy using FITC-conjugated annexin V and propidium iodide), morphologic (transmission electron microscopy), and molecular (agarose gel electrophoresis of cellular DNA fragments) criteria, it was documented that VT induced programmed cell death in microvascular endothelial cells in a dose- and time-dependent manner. Furthermore, whereas partial inhibition of protein synthesis by VT was associated with a considerable number of apoptotic cells, comparable inhibition of protein synthesis by cycloheximide was not. This suggests that additional pathways, independent of protein synthesis inhibition, may be involved in VT-mediated apoptosis in microvascular endothelial cells. Specific inhibition of caspases by Ac-Asp-Glu-Val-Asp-CHO, but not by Ac-Tyr-Val-Ala-Asp-CHO, was accompanied by inhibition of VT-induced apoptosis in FMVEC and TNF-alpha-treated GMVEC. These data indicate that VT can induce apoptosis in human microvascular endothelial cells.

In this study we have investigated the presence of apoptotic cells in renal biopsy material of seven patients with hemolytic uremic syndrome (HUS) by using an improved and stringent terminal deoxynucleotidyl nick-end labeling (TUNEL) technique. Renal biopsy material was taken in the second or third week after onset of the disease. Renal biopsy material of patients with minimal lesions nephrotic syndrome or thin basement syndrome were used as control. It has been reported that nonapoptotic cells can be labeled nonspecifically due to proteinase K pretreatment or a delay in fixation when only TUNEL technique is used. In post mortem material this delay in fixation is seen. Moreover, it has been described that mainly nonapoptotic cells that shows signs of active gene transcription can be labeled in this nonspecific way. For this reason we used the TUNEL technique in combination with a label for RNA synthesis and splicing factor (SC-35). Indeed, we found nonspecific labeling of nonapoptotic nuclei in biopsy material of HUS patients, but not in control biopsy material. By using co-labeling with RNA synthesis factor SC-35, we were able to identify true apoptotic cells. There was a significant increase (p < 0.05) in the presence of apoptotic cells in biopsy material of HUS patients compared with material of controls. About 80% of apoptotic cells were detected in tubuli and only 20% in glomeruli of the renal biopsies of HUS patients. Furthermore, most apoptotic cells were detected in those patients that had received peritoneal dialysis suggesting that there is a relationship between severity of the disease and amount of apoptotic cells. The finding of apoptotic cells suggest that apoptosis plays a role in HUS.

ObjectiveTo explore further the mechanisms leading to immune deficiency in chronic renal failure and the role of dialysis treatment in these mechanisms.DesignCross-sectional and longitudinal analysis.PatientsWe 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.MethodsWhite 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.ResultsThe total peripheral blood lymphocyte count was lower in PD children (2.6 x 109/L), HD children (2.1 x 109/L), and CRF children (2.0 x 109/L) compared with healthy children (3.1 x 109/L, p < 0.05). The B lymphocyte count was also lower in PD children (0.34x109/L), HD children (0.22 x 109/L), and CRF children (0.33 x 109/L) compared with healthy children (0.52 x 109/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 109/L), HD children (0.63 x 109/L), and CRF children (0.53 x 109/L) compared with healthy children (0.77 x 109/L, p < 0.05). The count of natural killer cells was lower in PD children (0.21 x 109/L), HD children (0.17 x 109/L), and CRF children (0.18 x 109/L) compared with healthy children (0.50 x 109/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 ≥ 1 per year.ConclusionsThe 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.

The hemolytic uremic syndrome (HUS) is the most common cause of acute renal failure in children. The role of a verocytotoxin (VT)-producing Escherichia coli has been strongly implicated in the epidemic form of HUS. Although direct toxicity of VT on glomerular endothelial cells has been demonstrated, it remained still unclear how the VT is transported from the intestine to the target organs. In this study we demonstrate that VT, when incubated in whole blood, binds rapidly and completely to human polymorphonuclear leukocytes (PMNs) and not to other components of blood. Binding studies with 125I-VT-1 showed a single class of binding sites on freshly isolated, non-stimulated human PMNs. The K(d) of VT-binding to PMNs was 10-8 mol/L, 100-fold less than that of the VT-receptor globotriaosylceramide. On incubation of VT-preloaded PMNs with human glomerular microvascular endothelial cells (GMVECs), transfer of VT-1 to the endothelial cells occurred. Incubation of non-stimulated GMVECs with VT- preloaded PMNs, but not with PMNs or VT-1 alone, caused inhibition of protein synthesis and cell death. Our data are in concert with a role of PMNs in the transfer of VT from the intestine to the kidney endothelium. This transfer occurs by selective binding to a specific receptor on PMNs and subsequent passing of the ligand VT to the VT-receptor on GMVECs, which causes cell damage. This new mechanism further underpins the important role of PMNs in HUS. (C) 2000 by The American Society of Hematology.

Item does not contain fulltext 4 p.

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.

During the period from September 1996 through November 1996, 10 Dutch dairy farms were visited to collect fecal samples from all cattle present. The samples were examined for the presence of verocytotoxin (VT)-producing Escherichia coli (VTEC) of serogroup O157 (O157 VTEC) by immunomagnetic separation following selective enrichment. Cattle on 7 of the 10 dairy farms tested positive for O157 VTEC, with the proportion of cattle infected varying from 0.8 to 22.4%. On the seven farms positive for O157 VTEC, the excretion rate was highest in calves ages 4 to 12 months (21.2%). In a follow-up study, two O157 VTEC-positive farms and two O157 VTEC-negative farms identified in the prevalence study were revisited five times at intervals of approximately 3 months. Cattle on each farm tested positive at least once. The proportion of cattle infected varied from 0 to 61.0%. Excretion rates peaked in summer and were lowest in winter. Again, the highest prevalence was observed in calves ages 4 to 12 months (11.8%). O157 VTEC strains were also isolated from fecal samples from horses, ponies, and sheep and from milk filters and stable flies. O157 VTEC isolates were characterized by VT production and type, the presence of the E. coli attaching-and-effacing gene, phage type, and pulsed-field gel electrophoretic genotype. No overlapping strain types were identified among isolates from different farms except one. The predominance of a single type at each sampling suggests that horizontal transmission is an important factor in dissemination of O157 VTEC within a farm. The presence of more than one strain type, both simultaneously and over time, suggests that there was more than one source of O157 VTEC on the farms. Furthermore, this study demonstrated that the O157 VTEC status of a farm cannot be ascertained from a single visit testing a small number of cattle.

Haemolytic-uraemic syndrome (HUS) is a clinical syndrome characterized by acute haemolytic anaemia with fragmented erythocytes, thrombocytopenia and acute renal failure. It is one of the leading causes of acute renal failure in childhood. HUS in children can be divided into the so-called typical, diarrhoea-associated HUS, and atypical HUS, which is not preceded by acute gastroenteritis. Infection with verocytotoxin-producing Escherichia coli is the main cause of diarrhoea-associated HUS. In this chapter the pathogenesis of diarrhoea-associated HUS and the role of verocytotoxin-producing Escherichia coli in this form of HUS is emphasized.

In the periods from July to November 1995 and 1996, fecal samples from Dutch cattle and sheep were collected at the main slaughterhouses of The Netherlands, located at different geographic sites. The samples were examined for the presence of verocytotoxin (VT)-producing Escherichia coli (VTEC) of serogroup O157. E. coli O157 strains could be isolated from 57 (10.6%) of 540 adult cattle, 2 (0.5%) of 397 veal calves, 2 (3.8%) of 52 ewes, and 2 (4.1%) of 49 lambs. Immunomagnetic separation with O157-specific-antibody-coated beads appeared to be significantly more sensitive than conventional plating for detection of the organism in feces. With the exception of two isolates from adult cattle which appeared to be negative for VT genes, all animal isolates were positive for both VT (VT1 and/or VT2) and E. coli attaching-and-effacing gene sequences, and therefore, they were regarded as potential human pathogens. Although genomic typing by pulsed-field gel electrophoresis revealed a wide variety of distinct restriction patterns, comparison of the 63 animal isolates with 33 fecal O157 VTEC strains previously isolated from humans with the diarrhea-associated form of the hemolytic-uremic syndrome by their phage types and VT genotypes showed a marked similarity between animal and human isolates: 30 (90.9%) of the 33 human isolates appeared to be of E. coli O157 strain types also isolated from cattle and sheep. It was concluded that Dutch cattle and sheep are an important reservoir of E. coli O157 strains that are potentially pathogenic for humans.

Agrin is a heparan sulfate proteoglycan (HSPG) that is highly concentrated in the synaptic basal lamina at the neuromuscular junction (NMJ). Agrin-like immunoreactivity is also detected outside the NMJ. Here we show that agrin is a major HSPG component of the human glomerular basement membrane (GBM). This is in addition to perlecan, a previously characterized HSPG of basement membranes. Antibodies against agrin and against an unidentified GBM HSPG produced a strong staining of the GBM and the NMJ, different from that observed with anti-perlecan antibodies. In addition, anti-agrin antisera recognized purified GBM HSPG and competed with an anti-GBM HSPG monoclonal antibody in ELISA. Furthermore, both antibodies recognized a molecule that migrated in SDS-PAGE as a smear and had a molecular mass of approximately 200-210 kD after deglycosylation. In immunoelectron microscopy, agrin showed a linear distribution along the GBM and was present throughout the width of the GBM. This was again different from perlecan, which was exclusively present on the endothelial side of the GBM and was distributed in a nonlinear manner. Quantitative ELISA showed that, compared with perlecan, the agrin-like GBM HSPG showed a sixfold higher molarity in crude glomerular extract. These results show that agrin is a major component of the GBM, indicating that it may play a role in renal ultrafiltration and cell matrix interaction. (J Histochem Cytochem 46:19-27, 1998)

McCune-Albright syndrome consists of the triad polyostotic fibrous dysplasia, cafe-au-lait spots and autonomous hyperfunction of one or more endocrine systems. The most frequent neurological complication of craniofacial fibrous dysplasia is visual loss. We describe a 17-y-old boy with McCune-Albright syndrome and acute loss of vision in the left eye caused by encroachment of the left optic nerve by fibrous dysplastic lesions. Neurosurgical intervention improved left eye vision. Aggressive intervention is indicated in cases of acute visual loss in patients with craniofacial fibrous dysplasia. This is supported by a review of other reported cases.

ObjectiveTo measure the urea and creatinine kinetics in a pediatric populationPatients and MethodsIn 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 nightly intermittent peritoneal dialysis (NIPD).ResultsMean 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 (pConclusionsMean 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.

Heparan sulfate proteoglycans (HSPGs) are essential components of the glomerular basement membrane (GBM) carrying a strong anionic charge. A well- characterized extracellular HSPG is perlecan, ubiquitously expressed in basement membranes. A cDNA construct encoding domains I and II of human perlecan was expressed as a fusion protein with glmathione S-transferase. This fusion protein was used to generate monoclonal antibody 95J10. We compared the staining pattern of 95J10 with that of M215, a previously prepared mAb that recognizes HSPG isolated from human GBM. In kidney cortex, the antiperlecan mAb 95J10 showed a strong staining of the mesangium, Bowman's capsule, the tubular basement membrane, and stained the GBM only slightly. In contrast, M215 predominantly stained the GBM in a linear fashion. Immunoelectron microscopy supported these results, showing concentrations of perlecan in some regions of the GBM, whereas the unidentified M215 antigen was homogemously distributed throughout the GBM. In other human tissues, both antibodies also produced a different staining pattern. Furthermore, a polyclonal antiserum recognizing HSPG isolated from the GBM did not recognize perlecan from EHS tumors. These results provide evidence for the presence of another HSPG in the GBM that is immunologically distinct froth perlecan. The absence of perlecan splice variants in the kidney suggests that this component is encoded by a different gene than perlecan. Given its marked expression in the GBM, this component could be a determining factor in the maintenance of selective glomerular permeability.