Abnormal kidney ultrasound and function in a five-year-old boy born prematurely with a birth weight of 370 grams.

It is known that prematurity and low birth weight are associated with chronic kidney disease and hypertension. A positive correlation between kidney volume and birth weight was also described. In our ongoing observational study in 5-year-old children, we perceived highly abnormal kidney ultrasound and functions of a male patient born weighing 370 grams. It was his first nephrology examination since discharge from the hospital. We believe that thorough follow up and timely diagnosis of developing renal insufficiency may help us to initiate proper treatment in high-risk children (Tab. 1, Fig. 1, Ref. 7). Text in PDF www.elis.sk Keywords: prematurity; extremely low birth weight; chronic kidney disease; renal ultrasound; renal function.

Effect of the DASH-diet and salt Kardisal® on blood pressure in adolescents with prehypertension (Cooperative multicentre interventional study).

BACKGROUND: In a cooperative multi-center interventional study of 60 probands with prehypertension and normal BMIs were followed for 3 months. DESIGN: The intervention included the DASH diet for 3 months in 30 probands plus sodium limited intake using the low sodium salt Kardisal® (60% NaCl, 40% KCl) (group A) and the DASH diet for 3 months in 30 probands without Kardisal® (group B). RESULTS: In group A (n=26 probands evaluated) the systolic blood pressure (median) decreased significantly from 138 to 129 mmHg (p<0.001), while the diastolic blood pressure had a statistically non-significant decrease. In group B (n=25 probands evaluated) the SBP decreased significantly from 135 to 132 mmHg (p<0.001), and the DBP decreased significantly from 85 to 69 mmHg (p<0.001). CONCLUSION: Despite a relatively short period on the DASH diet, the intervention produced a significant decrease in the blood pressure of prehypertensive adolescents. The additional use of a low sodium salt for home cooking was not found to have any advantages over the DASH diet alone.

Familial hematuria: A review.

The most frequent cause of familial glomerular hematuria is thin basement membrane nephropathy (TBMN) caused by germline COL4A3 or COL4A4 gene mutations. Less frequent but important cause with respect to morbidity is Alport syndrome caused by germline COL4A5 gene mutations. The features of Alport syndrome include hematuria, proteinuria and all males with X-linked disease and all individuals with recessive disease will develop end stage renal disease, usually at early youth. In X-linked Alport syndrome, a clear genotype-phenotype correlation is typically observed in men. Deleterious COL4A5 mutations are associated with a more severe renal phenotype and more frequent high-frequency sensorineural hearing loss and ocular abnormalities. Less severe COL4A5 mutations result in a milder phenotype, with less frequent and later onset extrarenal anomalies. The phenotype in females is highly variable, mostly due to inactivation of one of the X chromosomes. Isolated cases may be caused by de novo COL4A5 mutations or by gonosomal mosaicism. Untreated autosomal recessive Alport syndrome, caused by COL4A3 and COL4A4 mutations, is typically associated with ESRD at the age of 23-25 years and extrarenal symptoms in both men and women. The TBMN phenotype is associated with heterozygous carriers of COL4A3, COL4A4 mutations. Molecular genetic testing is the gold standard for diagnosing these diseases. Although genotype-phenotype correlations exist, the phenotype is influenced by modifying factors, which remain mainly undefined. No therapy is available that targets the cause of Alport syndrome; angiotensin-converting enzyme inhibitor therapy delays renal failure and improves lifespan.

Short Review of Child Health Care in Former Czechoslovakia and Czech Republic since 1993.

We provide an overview on child health care in Czech Republic, including a historical background. Child health care has substantially improved in Czech hospitals during the past 20 years. Eight pediatric departments are located in university hospitals. The technical background of pediatric services meets high international standards. Inpatient and outpatient care is offered on a 24-hour service, and all pediatric subspecialties are usually provided. The different pediatric subspecialties are organized in the frame of the Czech Pediatric Society, and all of them have developed dynamic international scientific collaborations. From the organizational point of view, the formation of specialized centers of competence at university departments of pediatrics followed a mixture of a "bottom-up and top-down strategy" of all opinion and decision makers.

Improving thermal and detergent stability of Bacillus stearothermophilus neopullulanase by rational enzyme design.

Neopullulanase, a glycosyl hydrolase from Bacillus stearothermophilus (bsNpl), is a potentially valuable enzyme for starch and detergent industries. However, as the protein is not active at elevated temperatures and high surfactant concentrations, we aimed to increase its stability by rational enzyme design. Nine potentially destabilizing cavities were identified in the crystal structure of the enzyme. Based on computational predictions, these cavities were filled by residues with bulkier side chains. The five Asp46Glu, Val239Leu, Val404Leu, Ser407Thr and Ala566Leu exchanges resulted in a drastic stabilization of bsNpl against inactivation by heat and detergents. The catalytic activity of the variants was identical to the wild-type enzyme.

H2rs: deducing evolutionary and functionally important residue positions by means of an entropy and similarity based analysis of multiple sequence alignments.

BACKGROUND: The identification of functionally important residue positions is an important task of computational biology. Methods of correlation analysis allow for the identification of pairs of residue positions, whose occupancy is mutually dependent due to constraints imposed by protein structure or function. A common measure assessing these dependencies is the mutual information, which is based on Shannon's information theory that utilizes probabilities only. Consequently, such approaches do not consider the similarity of residue pairs, which may degrade the algorithm's performance. One typical algorithm is H2r, which characterizes each individual residue position k by the conn(k)-value, which is the number of significantly correlated pairs it belongs to. RESULTS: To improve specificity of H2r, we developed a revised algorithm, named H2rs, which is based on the von Neumann entropy (vNE). To compute the corresponding mutual information, a matrix A is required, which assesses the similarity of residue pairs. We determined A by deducing substitution frequencies from contacting residue pairs observed in the homologs of 35 809 proteins, whose structure is known. In analogy to H2r, the enhanced algorithm computes a normalized conn(k)-value. Within the framework of H2rs, only statistically significant vNE values were considered. To decide on significance, the algorithm calculates a p-value by performing a randomization test for each individual pair of residue positions. The analysis of a large in silico testbed demonstrated that specificity and precision were higher for H2rs than for H2r and two other methods of correlation analysis. The gain in prediction quality is further confirmed by a detailed assessment of five well-studied enzymes. The outcome of H2rs and of a method that predicts contacting residue positions (PSICOV) overlapped only marginally. H2rs can be downloaded from http://www-bioinf.uni-regensburg.de. CONCLUSIONS: Considering substitution frequencies for residue pairs by means of the von Neumann entropy and a p-value improved the success rate in identifying important residue positions. The integration of proven statistical concepts and normalization allows for an easier comparison of results obtained with different proteins. Comparing the outcome of the local method H2rs and of the global method PSICOV indicates that such methods supplement each other and have different scopes of application.

Enterohemorrhagic Escherichia coli as causes of hemolytic uremic syndrome in the Czech Republic.

BACKGROUND: Enterohemorrhagic Escherichia coli (EHEC) cause diarrhea-associated hemolytic uremic syndrome (D+ HUS) worldwide, but no systematic study of EHEC as the causative agents of HUS was performed in the Czech Republic. We analyzed stools of all patients with D+ HUS in the Czech Republic between 1998 and 2012 for evidence of EHEC infection. We determined virulence profiles, phenotypes, antimicrobial susceptibilities and phylogeny of the EHEC isolates. METHODOLOGY/PRINCIPAL FINDINGS: Virulence loci were identified using PCR, phenotypes and antimicrobial susceptibilities were determined using standard procedures, and phylogeny was assessed using multilocus sequence typing. During the 15-year period, EHEC were isolated from stools of 39 (69.4%) of 56 patients. The strains belonged to serotypes [fliC types] O157:H7/NM[fliC(H7)] (50% of which were sorbitol-fermenting; SF), O26:H11/NM[fliC(H11)], O55:NM[fliC(H7)], O111:NM[fliC(H8)], O145:H28[fliC(H28)], O172:NM[fliC(H25)], and Orough:NM[fliC(H250]. O26:H11/NM[fliC(H11)] was the most common serotype associated with HUS (41% isolates). Five stx genotypes were identified, the most frequent being stx(2a) (71.1% isolates). Most strains contained EHEC-hlyA encoding EHEC hemolysin, and a subset (all SF O157:NM and one O157:H7) harbored cdt-V encoding cytolethal distending toxin. espPα encoding serine protease EspPα was found in EHEC O157:H7, O26:H11/NM, and O145:H28, whereas O172:NM and Orough:NM strains contained espPγ. All isolates contained eae encoding adhesin intimin, which belonged to subtypes ß (O26), γ (O55, O145, O157), γ2/θ (O111), and ε (O172, Orough). Loci encoding other adhesins (efa1, lpfA(O26), lpfA(O157OI-141), lpfA(O157OI-154), iha) were usually associated with particular serotypes. Phylogenetic analysis demonstrated nine sequence types (STs) which correlated with serotypes. Of these, two STs (ST660 and ST1595) were not found in HUS-associated EHEC before. CONCLUSIONS/SIGNIFICANCE: EHEC strains, including O157:H7 and non-O157:H7, are frequent causes of D+ HUS in the Czech Republic. Identification of unusual EHEC serotypes/STs causing HUS calls for establishment of an European collection of HUS-associated EHEC, enabling to study properties and evolution of these important pathogens.

CLIPS-4D: a classifier that distinguishes structurally and functionally important residue-positions based on sequence and 3D data.

MOTIVATION: The precise identification of functionally and structurally important residues of a protein is still an open problem, and state-of-the-art classifiers predict only one or at most two different categories. RESULT: We have implemented the classifier CLIPS-4D, which predicts in a mutually exclusively manner a role in catalysis, ligand-binding or protein stability for each residue-position of a protein. Each prediction is assigned a P-value, which enables the statistical assessment and the selection of predictions with similar quality. CLIPS-4D requires as input a multiple sequence alignment and a 3D structure of one protein in PDB format. A comparison with existing methods confirmed state-of-the-art prediction quality, even though CLIPS-4D classifies more specifically than other methods. CLIPS-4D was implemented as a multiclass support vector machine, which exploits seven sequence-based and two structure-based features, each of which was shown to contribute to classification quality. The classification of ligand-binding sites profited most from the 3D features, which were the assessment of the solvent accessible surface area and the identification of surface pockets. In contrast, five additionally tested 3D features did not increase the classification performance achieved with evolutionary signals deduced from the multiple sequence alignment.

Experimental assessment of the importance of amino acid positions identified by an entropy-based correlation analysis of multiple-sequence alignments.

The analysis of a multiple-sequence alignment (MSA) with correlation methods identifies pairs of residue positions whose occupation with amino acids changes in a concerted manner. It is plausible to assume that positions that are part of many such correlation pairs are important for protein function or stability. We have used the algorithm H2r to identify positions k in the MSAs of the enzymes anthranilate phosphoribosyl transferase (AnPRT) and indole-3-glycerol phosphate synthase (IGPS) that show a high conn(k) value, i.e., a large number of significant correlations in which k is involved. The importance of the identified residues was experimentally validated by performing mutagenesis studies with sAnPRT and sIGPS from the archaeon Sulfolobus solfataricus. For sAnPRT, five H2r mutant proteins were generated by replacing nonconserved residues with alanine or the prevalent residue of the MSA. As a control, five residues with conn(k) values of zero were chosen randomly and replaced with alanine. The catalytic activities and conformational stabilities of the H2r and control mutant proteins were analyzed by steady-state enzyme kinetics and thermal unfolding studies. Compared to wild-type sAnPRT, the catalytic efficiencies (k(cat)/K(M)) were largely unaltered. In contrast, the apparent thermal unfolding temperature (T(M)(app)) was lowered in most proteins. Remarkably, the strongest observed destabilization (ΔT(M)(app) = 14 °C) was caused by the V284A exchange, which pertains to the position with the highest correlation signal [conn(k) = 11]. For sIGPS, six H2r mutant and four control proteins with alanine exchanges were generated and characterized. The k(cat)/K(M) values of four H2r mutant proteins were reduced between 13- and 120-fold, and their T(M)(app) values were decreased by up to 5 °C. For the sIGPS control proteins, the observed activity and stability decreases were much less severe. Our findings demonstrate that positions with high conn(k) values have an increased probability of being important for enzyme function or stability.

CLIPS-1D: analysis of multiple sequence alignments to deduce for residue-positions a role in catalysis, ligand-binding, or protein structure.

BACKGROUND: One aim of the in silico characterization of proteins is to identify all residue-positions, which are crucial for function or structure. Several sequence-based algorithms exist, which predict functionally important sites. However, with respect to sequence information, many functionally and structurally important sites are hard to distinguish and consequently a large number of incorrectly predicted functional sites have to be expected. This is why we were interested to design a new classifier that differentiates between functionally and structurally important sites and to assess its performance on representative datasets. RESULTS: We have implemented CLIPS-1D, which predicts a role in catalysis, ligand-binding, or protein structure for residue-positions in a mutually exclusive manner. By analyzing a multiple sequence alignment, the algorithm scores conservation as well as abundance of residues at individual sites and their local neighborhood and categorizes by means of a multiclass support vector machine. A cross-validation confirmed that residue-positions involved in catalysis were identified with state-of-the-art quality; the mean MCC-value was 0.34. For structurally important sites, prediction quality was considerably higher (mean MCC = 0.67). For ligand-binding sites, prediction quality was lower (mean MCC = 0.12), because binding sites and structurally important residue-positions share conservation and abundance values, which makes their separation difficult. We show that classification success varies for residues in a class-specific manner. This is why our algorithm computes residue-specific p-values, which allow for the statistical assessment of each individual prediction. CLIPS-1D is available as a Web service at http://www-bioinf.uni-regensburg.de/. CONCLUSIONS: CLIPS-1D is a classifier, whose prediction quality has been determined separately for catalytic sites, ligand-binding sites, and structurally important sites. It generates hypotheses about residue-positions important for a set of homologous proteins and focuses on conservation and abundance signals. Thus, the algorithm can be applied in cases where function cannot be transferred from well-characterized proteins by means of sequence comparison.

Effect of donor/recipient body weight ratio, donor weight, recipient weight and donor age on kidney graft function in children.

BACKGROUND: We hypothesized that supplementing a higher mass of renal parenchyma from adult donors, and their younger age, would improve graft function in paediatric recipients. METHODS: We calculated estimated glomerular filtration rate (eGFR; Schwartz formula) and absolute glomerular filtration rate (absGFR) in 57 renal-grafted children (1995-2007) aged 3.1-17.9 years, weighing 12.9-85.0 kg, on discharge from the hospital after transplantation (TPL), 1 year after TPL and at the last follow-up (1.5-11.7 years after TPL). We correlated their eGFR with the individual ratio between the donor and the recipient body weight at the time of TPL (donor/recipient body weight ratio; D/R BWR), and we evaluated the effect of the donor and the actual recipient body weight on the eGFR and absGFR. RESULTS: The D/R BWR varied from 0.65 to 5.23. We found a significant positive correlation between D/R BWR and eGFR at discharge from the hospital (P < 0.001), 1-year post-TPL (P < 0.001) and at the last follow-up (P < 0.05). Using multiple linear regression analyses, we found that both eGFR and absGFR values were much more determined by the actual recipient weight than by the donor weight (27/6% and 43/4% at discharge, by 24/4% and 57/0% 1 year after TPL, and 0/0% and 20/0% at the end of the follow-up). A tendency for lower eGFR with increasing age of donors was apparent at discharge and 1 year after TPL, but it reached statistical significance only at the last follow-up (r = 0.4254, P < 0.01). CONCLUSION: In paediatric renal transplants, the value of D/R BWR directly correlated with eGFR in the early and late posttransplant periods. However, this correlation was mainly influenced by the recipient weight, while the donor weight played only a minor or negligible role.

Urinary transforming growth factor-ß1 in children with obstructive uropathy.

AIM: Obstructive uropathies (OU) in childhood constitute one of the major causes of chronic renal insufficiency. Transforming growth factor-ß1 (TGF-ß1) is considered to be the major fibrogenic growth factor. The aim of the present study was to investigate urinary TGF-ß1 levels in children with obstructive and non-obstructive uropathies (NOU). METHODS: This study involved 19 children with OU, 11 children with non-obstructive hydronephrosis and 21 healthy children. Urinary TGF-ß1, proteinuria, microalbuminuria and urinary α1-microglobulin were measured, and renal function was assessed. The results were statistically analyzed. RESULTS: Mean urinary TGF-ß1 concentrations in patients with OU were significantly higher than those with NOU (4.14 ± 0.67 creatinine vs 1.80 ± 0.24 pg/mmol creatinine, P < 0.05) and healthy controls (1.66 ± 0.28 pg/mmol creatinine, P < 0.05). Positive correlations of urinary TGF-ß1 concentrations with proteinuria (r = 0.87, P < 0.0001) and urinary α1-microglobulin (r = 0.82, P = 0.0002) were found in patients with OU. CONCLUSION: Children with OU have higher urinary TGF-ß1 than children with NOU. Urinary TGF-ß1 may be a useful non-invasive tool for the differential diagnosis between OU and NOU in children. A positive correlation of TGF-ß1 with markers of renal tissue damage in patients with OU was found.

Ramipril in the treatment of proteinuria in children after renal transplantation.

The efficacy and safety of ACEI in adult patients with hypertension and proteinuria after renal transplantation is proven however data on the effectiveness of ACEI in transplanted children are rare. The aim of the present study was to investigate the effect of ramipril on proteinuria and BP in children after R-Tx. Twelve transplanted children (median age 15.3 yr, median time after R-Tx 4.5 yr) with proteinuria with or without hypertension were prospectively treated with ramipril for six months. Proteinuria was assessed as protein/creatinine ratio. Office BP was evaluated and hypertension defined as BP > or =95th centile. Graft function was assessed (Schwartz formula). The starting dose of ramipril was 1.5 mg/m(2)/24-h. Proteinuria declined in 92% of children from a median 39 to 22 mg/mmol creatinine (p < 0.01). The median decline of proteinuria was 9 mg/mmol creatinine, it reached 23% of the initial values. The prevalence of hypertension did not change significantly (50% initially vs. 33% after six months). Graft function and serum potassium level did not change significantly, two children developed mild hyperkalemia. Ramipril can reduce proteinuria in most transplanted children; its antiproteinuric effect is exhibited even without BP lowering effect.

Arterial HTN in children with T1DM--frequent and not easy to diagnose.

INTRODUCTION: To evaluate the diagnostic efficacy of the office blood pressure (OBP) and ambulatory blood pressure monitoring (ABPM) in the assessment of hypertension (HTN) in children with diabetes mellitus type 1 (T1DM). METHODS: We analyzed OBP and ABPM measurements in 84 diabetic children (43 boys) obtained at a median age of 14.9 yr and 6.3 +/- 3.5 yr after diagnosis of T1DM. OBP and ABPM results were converted into standard deviation scores (SDS). In addition, we analyzed blood pressure loads and nighttime dipping. The comparison between OBP and ABPM was performed using kappa coefficient and receiver operator curve (ROC). RESULTS: HTN was diagnosed in 43/84 (51%) patients using OBP (>95th percentile), and in 24/84 (29%) patients using ABPM ( > or = 95th percentile during 24 h, day or night). Both methods were in agreement in 33 ABPM normotensive and 16 ABPM hypertensive patients (most had nighttime HTN); 32% patients had white-coat HTN and 9.5% patients had masked HTN. The kappa coefficient was 0.175 (95% CI from -0.034 to 0.384) suggesting poor agreement between OBP and ABPM. Diastolic OBP was a better predictor of ABPM HTN (ROC area under the curve (AUC) = 0.71 +/- 0.06) than systolic OBP (AUC = 0.58 +/- 0.07). The percentage of non-dippers ranged from 7 to 23% in ABPM normotensive patients, and 21-42% in ABPM hypertensive patients who also had significantly higher BP loads (p < 0.0001). CONCLUSION: Children with T1DM often suffer from nocturnal, white coat- and masked HTN, which can not be assessed and predicted by the OBP.

Partial remission with cyclosporine A in a patient with nephrotic syndrome due to NPHS2 mutation.

Autosomal recessive steroid-resistant nephrotic syndrome (NS) is a rare, genetically determined nephropathy caused mainly by a mutation in the NPHS2 gene. This type of NS is usually resistant to other immunosuppressive therapy as well, but a few cases of cyclosporine A-induced partial remission of inherited NS have been reported. We present a boy that developed NS at the age of 18 months. There was no decrease of proteinuria on standard prednisolone therapy, and a diagnosis of steroid-resistant NS was established. However, the proteinuria decreased significantly following the initiation of cyclosporine A therapy (from 1280 to 380 mg/m(2) per day) without any negative effects on renal function (stable glomerular filtration rate 130-150 ml/min per 1.73 m(2)). The molecular genetic test revealed a homozygous R138Q mutation in the NPHS2 gene. Our case demonstrates that cyclosporine A can induce partial remission in patients with genetic forms of NS without influencing the glomerular filtration rate. However, its long-term effect and safety in children with hereditary forms of nephrotic syndrome have yet to be investigated.

Genotype-phenotype correlation in children with autosomal dominant polycystic kidney disease.

Adults with autosomal dominant polycystic kidney disease (ADPKD) and PKD1 mutations have a more severe disease than do patients with PKD2 mutations. The aim of this study was to compare phenotypes between children with mutations in the PKD1/PKD2 genes. Fifty PKD1 children and ten PKD2 children were investigated. Their mean age was similar (8.6 +/- 5.4 years and 8.9 +/- 5.6 years). Renal ultrasound was performed, and office blood pressure (BP), ambulatory BP, creatinine clearance and proteinuria were measured. The PKD1 children had, in comparison with those with PKD2, significantly greater total of renal cysts (13.3 +/- 12.5 vs 3.0 +/- 2.1, P = 0.004), larger kidneys [right/left kidney length 0.89 +/- 1.22 standard deviation score (SDS) vs 0.17 +/- 1.03 SDS, P = 0.045, and 1.19 +/- 1.42 SDS vs 0.12 +/- 1.09 SDS, P = 0.014, successively] and higher ambulatory day-time and night-time systolic BP (day-time/night-time BP index 0.93 +/- 0.10 vs 0.86 +/- 0.05, P = 0.021 and 0.94 +/- 0.07 vs 0.89 +/- 0.04, P = 0.037, successively). There were no significant differences in office BP, creatinine clearance or proteinuria. Prenatal renal cysts (14%), hypertension defined by ambulatory BP (27%) and enlarged kidneys (32%) were observed only in the PKD1 children. This is the first study on genotype-phenotype correlation in children with ADPKD. PKD1 children have more and larger renal cysts, larger kidneys and higher ambulatory BP than do PKD2 children. Renal cysts and enlarged kidneys detected prenatally are highly specific for children with PKD1.