Analysis of annual distributions of hemoglobin A2 values as a method to test for HbA2 standardization

BACKGROUND AND AIMS

The monitoring of yearly distributions of HbA2 measured has been indicated as a reliable indicator of worldwide standardization.

MATERIALS AND METHODS

Measurements/year of HbA2 have been collected over three consecutive years in 15 Italian laboratories each using the same analytical method over three years period. HbA2 distributions, cleaned of replicated measurements, were compared by the overlapping area of the raw probability density functions expressed by coefficient eta (η), and by comparing the reference intervals for the central part of each distribution estimated by the indirect method refineR using the R package "refineR".

RESULTS

According to the overlapping areas analysis the distributions/year of the data provided by 4 centers able to perform at least 1000 measurements/year were similar in 2 consecutive years. Moreover, the reference intervals provided by 2 centers using the same analytical methods in two separate locations over the three consecutive years, were very similar. The highest overlap (99.7 %) was observed in one center over two consecutive years. The overlapping areas were very high (93.6-95.7%) in 8 out of 9 inter-comparisons.

CONCLUSION

Despite the limitations of this study the yearly distribution of the HbA2 measured in various centers appears a reliable tool to test HbA2 standardization over different centers using different analytical methods.

Moyamoya disease presenting with tubular dysfunction in a child: pitfalls in diagnosing an atypical hyponatremic-hypertensive syndrome

BACKGROUND

Moyamoya disease, a cause of pediatric stroke, has been shown to affect furthermore extra-cranial districts, mostly the kidney arterial site, resulting in steno-occlusive changes. Unilateral renal artery stenosis accounts for 8%-10% out of cases of renovascular hypertension in childhood, however it rarely underlies a hyponatremic-hypertensive syndrome (HHS).

CASE PRESENTATION

We describe an 18-month-old boy with a recent history of polyuria and polydipsia, who presented an acute febrile gastroenteritis with neurological impairment, severe dehydration, hyponatremia, hypokalemia, kidney tubular dysfunction, and elevated aldosterone and renin even with a normal blood pressure. Fluid and electrolytes correction was performed, with complete recovery. An abdominal ultrasound displayed a smaller right kidney. A brain magnetic resonance and an electroencephalogram did not show any relevant abnormalities. Five months later, the child experienced a left-side hemiparesis after a traumatic concussion, and a severe hypertension. A brain tomography documented a cerebral ischemia. Brain and kidney angiographic studies displayed puff of smoke findings of internal right carotid artery branches and a steno-occlusive pattern of right renal artery, respectively. Hence, moyamoya disease with HHS secondary to unilateral renal artery stenosis was diagnosed. After an unsuccessful antiplatelet and antihypertensive pharmacological treatment, the boy underwent a renal angioplasty and a cerebral STA-MCA bypass (direct superficial temporal artery-to-middle cerebral artery bypass), resulting in a significant improvement of both neurological and kidney disease.

CONCLUSIONS

Although the association between unilateral renal artery stenosis and HHS has been previously shown, this is the first report of atypical HHS, with hypertension preceded by tubular dysfunction, recognized in the framework of moyamoya disease.

The process of transition from pediatric to adult healthcare services for nephrological patients: Recommendations vs. reality-A single center experience

Transitional care is an essential step for patients with kidney disease, and it is supported by policy documents in the United Kingdom and United States. We have previously described the heterogeneous situation currently found in Europe regarding certain aspects of transitional care: the written transition plan, the educational program, the timing of transfer to adult services, the presence of a coordinator and a dedicated off-site transition clinic. In line with the transition protocol "RISE to transition," the objective of this paper is to describe the experience of the Bologna center in defining a protocol for the management of chronic kidney disease and the difficulties encountered in implementing it. We apply this model to various chronic diseases along the process of transfer to adult services. It begins when the patient is 14 years old and is complete by the time they reach 18. The family is continuously involved and all the patients in transitional care receive continuous medical care and psychological support. We identified a series of tests designed to measure various criteria: medical condition, psychological state, quality of life, and degree of patient satisfaction, which are repeated at set intervals during the transition process. The organization of the service provided an adequate setting for taking charge of the patients in the long term. The transition program implemented by the adult and pediatric nephrology services of the Bologna center has lowered the risk of discontinuity of care and greatly improved the patients' awareness of responsibility for their own healthy lifestyle choices.

Insights from the 4C-T Study suggest increased cardiovascular burden in girls with end stage kidney disease before and after kidney transplantation

Mortality in children with kidney failure is higher in girls than boys with cardiovascular complications representing the most common causes of death. Pulse wave velocity (PWV), a measure of vascular stiffness, predicts cardiovascular mortality in adults. Here, PWV in children with kidney failure undergoing kidney replacement therapy was investigated to determine sex differences and potential contributing factors. Two-hundred-thirty-five children (80 girls; 34%) undergoing transplantation (150 pre-emptive, 85 with prior dialysis) having at least one PWV measurement pre- and/or post-transplantation from a prospective cohort were analyzed. Longitudinal analyses (median/maximum follow-up time of 6/9 years) were performed for PWV z-scores (PWVz) using linear mixed regression models and further stratified by the categories of time: pre-kidney replacement therapy and post-transplantation. PWVz significantly increased by 0.094 per year and was significantly higher in girls (PWVz +0.295) compared to boys, independent of the underlying kidney disease. During pre-kidney replacement therapy, an average estimated GFR decline of 4ml/min/1.73m² per year was associated with a PWVz increase of 0.16 in girls only. Higher diastolic blood pressure and low density lipoprotein were independently associated with higher PWVz during pre-kidney replacement therapy in both sexes. In girls post-transplantation, an estimated GFR decline of 4ml/min/1.73m² per year pre-kidney replacement therapy and a longer time (over 12 months) to transplantation were significantly associated with higher PWVz of 0.22 and of 0.57, respectively. PWVz increased further after transplantation and was positively associated with time on dialysis and diastolic blood pressure in both sexes. Thus, our findings demonstrate that girls with advanced chronic kidney disease are more susceptible to develop vascular stiffening compared to boys, this difference persist after transplantation and might contribute to higher mortality rates seen in girls with kidney failure.

Acute pediatric kidney replacement therapies in Europe: demographic results from the EurAKId Registry

BACKGROUND

Acute kidney injury (AKI), particularly that requiring dialysis, is a severe complication in hospitalized children associated with high morbidity and mortality. A prospective European AKI registry (EurAKId registry, NCT02960867) was created to describe the epidemiology and outcomes of pediatric patients treated with acute dialysis.

METHODS

Children were recruited who were between 0 and 18 years of age and were treated both in and outside the Pediatric Intensive Care Unit (PICU) with peritoneal dialysis (PD), hemodialysis (HD) or continuous kidney replacement therapy (CKRT) for AKI or metabolic derangement, fluid overload (FO), sepsis, or respiratory distress. Five age groups and 12 categories of primary diseases were defined.

RESULTS

Data on 340 patients were analyzed, of whom 86% received dialysis for AKI and 14% for reasons other than AKI. Boys accounted for 60% of the patients. Illness severity was greater in children with cardiac and hematologic diseases than those with kidney diseases. Most patients received dialysis in the PICU (84%). The most frequently used dialysis modality was CKRT (64%), followed by PD (14%) and HD (14%). The overall survival rate was 65%. Survival was significantly lower in children with three comorbidities than in children with no comorbidities (41% and 83%, p < 0.001).

CONCLUSIONS

The EurAKId registry is the first prospective registry considering pediatric acute kidney replacement therapies (KRT) in both critical and non-critical care settings, focusing on the three dialysis modalities in Europe. The clinical indications for KRT have expanded; our population was characterized by critically ill patients, primarily boys, who frequently received dialysis in the PICU with CKRT.

Childhood Idiopathic Nephrotic Syndrome: Does the Initial Steroid Treatment Modify the Outcome? A Multicentre, Prospective Cohort Study

Background: A great majority of children with idiopathic nephrotic syndrome will relapse after successful treatment of the initial episode. The possibility that different steroid dosing regimens at onset, adjusted for risk factors, can reduce the rate of relapse represents an interesting option to investigate. Objectives: To evaluate the effect of the initial steroid regimen, adjusted for time to remission (TTR), on the frequency of relapses and steroid dependence, and to verify the influence of prognostic factors on disease course. Methods: A multicentre, prospective, cohort study. Children with nephrotic syndrome, with TTR ≤ 10 days (Group A), were given a 20-week prednisone regimen (2,828 mg/m2) and those with a TTR >10 days, a 22-week regimen (3,668 mg/m2) (Group B). Previously published retrospective data from the same centers were also evaluated. Main outcomes were: relapse rate, number of frequent relapsers + steroid dependent children and total prednisone dose after induction. Results: 143 children were enrolled. Rate of relapsed subjects (77 vs. 79%) and frequent relapsers + steroid dependent subjects (40 vs. 53%) did not differ between Groups A and B, or between the retrospective and prospective cohorts. The cumulative prednisone dose taken after the induction treatment was similar in both groups and in the retrospective and prospective cohorts. TTR was not associated with relapse risk. Age at onset and total serum protein were significantly lower in relapsing patients. At ROC analysis, the best cut-off was 5.3 years for age at onset and 4.2 g/dL for total serum protein. According to these cut-offs, older children with higher total serum protein had a higher relapse free survival rate (58%) than younger children with lower total serum protein (17%). Conclusions: TTR was not found to be a prognostic factor of relapse; because of this, different steroid regimens, adjusted for TTR, did not modify the relapse rate in any relevant measure. Conversely, younger age and low total serum protein were independent predictors of relapse risk, however this outcome was not modified by higher prednisone regimens. Clinical Trial Registration:https://www.ClinicalTrials.gov/, identifier: NCT01386957 (www.nefrokid.it).

Aetiology, course and treatment of acute tubulointerstitial nephritis in paediatric patients: a cross-sectional web-based survey

BACKGROUND

Acute tubulointerstitial nephritis (TIN) is a significant cause of acute renal failure in paediatric and adult patients. There are no large paediatric series focusing on the aetiology, treatment and courses of acute TIN.

PATIENTS, DESIGN AND SETTING

We collected retrospective clinical data from paediatric patients with acute biopsy-proven TIN by means of an online survey. Members of four professional societies were invited to participate.

RESULTS

Thirty-nine physicians from 18 countries responded. 171 patients with acute TIN were included (54% female, median age 12 years). The most frequent causes were tubulointerstitial nephritis and uveitis syndrome in 31% and drug-induced TIN in 30% (the majority of these caused by non-steroidal anti-inflammatory drugs). In 28% of patients, no initiating noxae were identified (idiopathic TIN). Median estimated glomerular filtration rate (eGFR) rose significantly from 31 at time of renal biopsy to 86 mL/min/1.73 m² 3-6 months later (p<0.001). After 3-6 months, eGFR normalised in 41% of patients (eGFR ≥90 mL/min/1.73 m²), with only 3% having severe or end-stage impairment of renal function (<30 mL/min/1.73 m²). 80% of patients received corticosteroid therapy. Median eGFR after 3-6 months did not differ between steroid-treated and steroid-untreated patients. Other immunosuppressants were used in 18% (n=31) of patients, 21 of whom received mycophenolate mofetil.

CONCLUSIONS

Despite different aetiologies, acute paediatric TIN had a favourable outcome overall with 88% of patients showing no or mild impairment of eGFR after 3-6 months. Prospective randomised controlled trials are needed to evaluate the efficacy of glucocorticoid treatment in paediatric patients with acute TIN.

Multidisciplinarity in Transition Pathways for Patients With Kidney Disease: The Current State of Play

In the field of medical care, successful transition from pediatric-centered to adult-oriented healthcare can provide a sense of continuity in the development of youth, and prepare them to accept responsibility for and manage their own chronic kidney condition in complete autonomy. The so-called transition process requires the presence of some basic aspects: a multidisciplinary team, which acts as a bridge between child and adult services; a comprehensive clinical, cognitive, psychological, and social change for the young people; the involvement of family and caregivers. Within the framework of transition and chronicity during the developmental age, we selected international papers explaining models which agreed on some important steps in the transition process, although many differences can be observed between different countries. In fact, in Europe, the situation appears to be heterogeneous as regards certain aspects: the written transition plan, the educational programmes, the timing of transfer to adult services, the presence of a transition coordinator, a dedicated off-site transition clinic. We then analyzed some studies focusing on patients with renal diseases, including the first to contain a standardized protocol for transition which was launched recently in the USA, and which seems to have already achieved important positive, although limited, results. In Italy, the issue of transition is still in its infancy, however important efforts in the management of chronic kidney disease have already been initiated in some regions, including Emila Romagna, which gives us hope for the future of many young people.

Gene Panel Analysis in a Large Cohort of Patients With Autosomal Dominant Polycystic Kidney Disease Allows the Identification of 80 Potentially Causative Novel Variants and the Characterization of a Complex Genetic Architecture in a Subset of Families

Introduction: Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common inherited disorders in humans and the majority of patients carry a variant in either PKD1 or PKD2. Genetic testing is increasingly required for diagnosis, prognosis, and treatment decision, but it is challenging due to segmental duplications of PKD1, genetic and allelic heterogeneity, and the presence of many variants hypomorphic or of uncertain significance. We propose an NGS-based testing strategy for molecular analysis of ADPKD and its phenocopies, validated in a diagnostic setting. Materials and Methods: Our protocol is based on high-throughput simultaneous sequencing of PKD1 and PKD2 after long range PCR of coding regions, followed by a masked reference genome alignment, and MLPA analysis. A further screening of additional 14 cystogenes was performed in negative cases. We applied this strategy to analyze 212 patients with a clinical suspicion of ADPKD. Results and Discussion: We detected causative variants (interpreted as pathogenic/likely pathogenic) in 61.3% of our index patients, and variants of uncertain clinical significance in 12.5%. The majority (88%) of genetic variants was identified in PKD1, 12% in PKD2. Among 158 distinct variants, 80 (50.6%) were previously unreported, confirming broad allelic heterogeneity. Eleven patients showed more than one variant. Segregation analysis indicated biallelic disease in five patients, digenic in one, de novo variant with unknown phase in two. Furthermore, our NGS protocol allowed the identification of two patients with somatic mosaicism, which was undetectable with Sanger sequencing. Among patients without PKD1/PKD2 variants, we identified three with possible alternative diagnosis: a patient with biallelic mutations in PKHD1, confirming the overlap between recessive and dominant PKD, and two patients with variants in ALG8 and PRKCSH, respectively. Genotype-phenotype correlations showed that patients with PKD1 variants predicted to truncate (T) the protein experienced end-stage renal disease 9 years earlier than patients with PKD1 non-truncating (NT) mutations and >13 years earlier than patients with PKD2 mutations. ADPKD-PKD1 ^T cases showed a disease onset significantly earlier than ADPKD-PKD1 ^NT and ADPK-PKD2, as well as a significant earlier diagnosis. These data emphasize the need to combine clinical information with genetic data to achieve useful prognostic predictions.

Born with a solitary kidney: at risk of hypertension

BACKGROUND

Subjects with a congenital solitary kidney (CSK) are believed to be at risk of hypertension due to their low number of nephrons. However, as CSK is a congenital abnormality of the kidney or urinary tract (CAKUT), subtle dysplastic changes contributing to hypertension cannot be excluded.

METHODS

We retrospectively compared office blood pressure (OBP) and ambulatory blood pressure monitoring (ABPM) between two groups of children with CAKUT, aged 6-18 years: Group A with a CSK and Group B with two kidneys. All had normal renal parenchyma on scintigraphy and normal renal function. OBP and mean systolic and diastolic 24-h, daytime and nighttime ambulatory BP records were analyzed. The distribution of OBP and APBM as continuous values and the prevalence of hypertension (ambulatory/severe ambulatory or masked hypertension) in the two groups were compared.

RESULTS

There were 81 patients in Group A and 45 in Group B. Median OBP standard deviation scores were normal in both groups, without significant differences. Median ABPM standard deviation scores, although normal, were significantly higher in Group A and the prevalence of hypertension was higher (ambulatory/severe ambulatory or masked) (33.3 vs. 13.3%, p = 0.019), mainly because of the greater occurrence of masked hypertension.

CONCLUSIONS

Our data show that a CSK per se can be associated with an increased risk of hypertension from the pediatric age. Therefore, ABPM, which has proved valuable in the screening of hypertension, is warranted in children with a CSK, even if laboratory and imaging assessment is otherwise normal.

Effect of Body Mass Index on Estimated Glomerular Filtration Rate Levels in Children With Congenital Solitary Kidney: A Cross-Sectional Multicenter Study

RATIONALE & OBJECTIVE

The objective of this study is to evaluate the effect of body mass index (BMI) on estimated glomerular filtration rate (eGFR) levels in children with congenital solitary kidney (CSK). Moreover, we evaluated if other factors could influence this relationship.

STUDY DESIGN

Multicenter cross-sectional study.

SETTING & PARTICIPANTS

University hospital pediatrics departments.

SUBJECTS

Two hundred eighty-one patients with CSK.

PREDICTORS

Weight, height, BMI-SDS (standard deviation score), duration of overweight/obesity, pubertal stage, systolic (SBP) and diastolic (DBP) blood pressure, eGFR, and renal ultrasound were obtained at the last follow-up visit. The population was classified on the basis of nutritional status and divided in tertiles for duration of overweight/obesity. We compared eGFR levels among these categories. A simple regression was used to correlate eGFR with BMI-SDS. To evaluate if other factors could influence the relationship between eGFR and BMI-SDS, a general linear model was performed, including gender, birth weight<2.5 kg, age, BMI-SDS, SBP-SDS, DBP-SDS, RL-SDS (renal length), and presence of kidney injury at last follow-up as covariates.

RESULTS

The eGFR levels reduced gradually from underweight to obese patients (P = .047). The eGFR levels significantly increased across first and second tertiles of duration of overweight/obesity while they decreased across second and third tertiles of duration of overweight/obesity (P = .005). The eGFR and BMI-SDS at last follow-up were indirectly correlated (coefficient = -0.30, r² = 9.2%, P = .0004). A general linear model for eGFR variance (model R² = 26.37%; P = .02) confirmed an indirect and significant association of eGFR values with BMI-SDS as the only significant finding.

CONCLUSIONS

In patients with CSK, the higher the BMI-SDS and the duration of overweight/obesity, the lower the eGFR levels. Primary prevention strategies to counteract overweight/obesity are mandatory in CSK patients.

MIF plasma level as a possible tool to predict steroid responsiveness in children with idiopathic nephrotic syndrome

PURPOSE

Idiopathic nephrotic syndrome (INS) is the most frequent form of childhood nephrotic syndrome. Steroids represent the best therapeutic option; however, inter-individual differences in their efficacy and side effects have been reported. To date, there is no way to predict patients' resistance and/or dependence. Alterations in the cytokine profile of INS patients might contribute to proteinuria and glomerular damage and affect drug sensitivity.

METHODS

The cytokine plasma levels were measured in 21 INS children at diagnosis to investigate the association among cytokines pattern and clinical response. Patients were selected on the basis of their clinical response: 7 steroid sensitive (SS), 7 dependent (SD), and 7 resistant (SR). Significant results were then analyzed in 41 additional pediatric INS patients.

RESULTS

Within the 48 cytokines analyzed, macrophage migration inhibitory factor (MIF) was a good predictor of steroid response. Indeed, SR patients showed significantly higher MIF plasma levels compared with all others (p = 0.022; OR = 4.3, 95%CI = 1.2-25.4): a cutoff concentration of MIF > 501 pg/ml significantly discriminated SR patients (sensitivity = 85.7%, specificity = 71.4%). On the contrary, SD patients showed lower MIF plasma levels compared with others (p = 0.010; OR = 0.12, 95%CI = 9.2 × 10^-3-6.7 × 10^-1). Significant results were confirmed in the entire cohort.

CONCLUSIONS

Our comprehensive cytokine analysis indicates that assessing MIF plasma levels at diagnosis could predict response to glucocorticoids in children with INS.

Acute dialysis in children: results of a European survey

The number of children with acute kidney injury (AKI) requiring dialysis is increasing. To date, systematic analysis has been largely limited to critically ill children treated with continuous renal replacement therapy (CRRT). We conducted a survey among 35 European Pediatric Nephrology Centers to investigate dialysis practices in European children with AKI. Altogether, the centers perform dialysis in more than 900 pediatric patients with AKI per year. PD and CRRT are the most frequently used dialysis modalities, accounting for 39.4% and 38.2% of treatments, followed by intermittent HD (22.4%). In units treating more than 25 cases per year and in those with cardiothoracic surgery programs, PD is the most commonly chosen dialysis modality. Also, nearly one quarter of centers, in countries with a gross domestic product below $35,000/year, do not utilize CRRT at all. Dialysis nurses are exclusively in charge of CRRT management in 45% of the cases and pediatric intensive care nurses in 25%, while shared management is practiced in 30%. In conclusion, this survey indicates that the choice of treatment modalities for dialysis in children with AKI in Europe is affected by the underlying ethiology of the disease, organization/set-up of centers and socioeconomic conditions. PD is utilized as often as CRRT, and also intermittent HD is a commonly applied treatment option. A prospective European AKI registry is planned to provide further insights on the epidemiology, management and outcomes of dialysis in pediatric AKI.

Determinants of Statural Growth in European Children With Chronic Kidney Disease: Findings From the Cardiovascular Comorbidity in Children With Chronic Kidney Disease (4C) Study

Failure of statural growth is one of the major long-term sequelae of chronic kidney disease (CKD) in children. In recent years effective therapeutic strategies have become available that lead to evidence based practice recommendations. To assess the current growth performance of European children and adolescents with CKD, we analyzed a cohort of 594 patients from 12 European countries who were followed prospectively for up to 6 years in the 4C Study. While all patients were on conservative treatment with a mean estimated glomerular filtration rate of 28 ml/min/1.73 m² at study entry, 130 children commenced dialysis during the observation period. At time of enrolment the mean height standard deviation score (SDS) was -1.57; 36% of patients had a height below the third percentile. The prevalence of growth failure varied between countries from 7 to 44% Whereas patients on conservative treatment showed stable growth, height SDS gradually declined on those on dialysis. Parental height, pubertal status and treatment with recombinant growth hormone (GH) were positively, and the diagnosis of syndromic disease and CKD stage were negatively associated with height SDS during the observation period. Unexpectedly, higher body mass index (BMI) SDS was associated with lower height SDS both at enrolment and during follow up. Renal anemia, metabolic acidosis, and hyperparathyroidism were mostly mild and not predictive of growth rates by multivariable analysis. GH therapy was applied in only 15% of growth retarded patients with large variation between countries. When adjusting for all significant covariates listed above, the country of residence remained a highly significant predictor of overall growth performance. In conclusion, growth failure remains common in European children with CKD, despite improved general management of CKD complications. The widespread underutilization of GH, an approved efficacious therapy for CKD-associated growth failure, deserves further exploration.

Metabolic acidosis is common and associates with disease progression in children with chronic kidney disease

Recent studies in adult chronic kidney disease (CKD) suggest that metabolic acidosis is associated with faster decline in estimated glomerular filtration rate (eGFR). Alkali therapies improve the course of kidney disease. Here we investigated the prevalence and determinants of abnormal serum bicarbonate values and whether metabolic acidosis may be deleterious to children with CKD. Associations between follow-up serum bicarbonate levels categorized as under 18, 18 to under 22, and 22 or more mmol/l and CKD outcomes in 704 children in the Cardiovascular Comorbidity in Children with CKD Study, a prospective cohort of pediatric patients with CKD stages 3-5, were studied. The eGFR and serum bicarbonate were measured every six months. At baseline, the median eGFR was 27 ml/min/1.73m² and median serum bicarbonate level 21 mmol/l. During a median follow-up of 3.3 years, the prevalence of metabolic acidosis (serum bicarbonate under 22 mmol/l) was 43%, 60%, and 45% in CKD stages 3, 4, and 5, respectively. In multivariable analysis, the presence of metabolic acidosis as a time-varying covariate was significantly associated with log serum parathyroid hormone through the entire follow-up, but no association with longitudinal growth was found. A total of 211 patients reached the composite endpoint (ESRD or 50% decline in eGFR). In a multivariable Cox model, children with time-varying serum bicarbonate under 18 mmol/l had a significantly higher risk of CKD progression compared to those with a serum bicarbonate of 22 or more mmol/l (adjusted hazard ratio 2.44; 95% confidence interval 1.43-4.15). Thus, metabolic acidosis is a common complication in pediatric patients with CKD and may be a risk factor for secondary hyperparathyroidism and kidney disease progression.

[Kidney Transplantation and inborn errors of metabolism]

Inherited kidney diseases constitute at least 150 different disorders and they have an overall prevalence of about 6080 cases per 100 000 in Europe and in USA. At least 10% of adults and nearly all children who progress to renal-replacement therapy have an inherited kidney disease, representing the fifth most common cause of end-stage renal disease after diabetes, hypertension, glomerulonephritis, and pyelonephritis. These conditions include both structural and functional disorders, among which are counted diseases resulting from inborn errors of metabolism (IEM). Some inborn errors of metabolism primarily affect kidney and because of progress in renal replacement therapy, patients with inherited kidney disorders rarely die when their disease progresses and can live for many years. However, these patients often have compromised health with a poor quality of life. Renal transplantation offers a viable treatment option for those inborn errors of metabolism characterized by primary renal damage caused by dysfunction of a mutated protein, as in cystinuria. In this case, the indication to renal transplantation makes it possible to overcome the specific enzyme defect. However this option remains valid even when the genetic defect is expressed systemically and renal involvement is just one of the clinical manifestations of the disease, as in Anderson-Fabry disease, cystinosis, hereditary amyloidosis and primary hyperoxaluria. In these conditions, renal transplantation is combined with the liver (primary hyperoxaluria) or cardiac transplant (familial amyloidosis) improving the quality and life expectancy of patients.

[Kidney Transplantation and inborn errors of metabolism]

Inherited kidney diseases constitute at least 150 different disorders and they have an overall prevalence of about 6080 cases per 100,000 in Europe and in USA. At least 10% of adults and nearly all children who progress to renal-replacement therapy have an inherited kidney disease, representing the fifth most common cause of end-stage renal disease after diabetes, hypertension, glomerulonephritis, and pyelonephritis. These conditions include both structural and functional disorders, among which are counted diseases resulting from inborn errors of metabolism (IEM). Some inborn errors of metabolism primarily affect kidney and because of progress in renal replacement therapy, patients with inherited kidney disorders rarely die when their disease progresses and can live for many years. However, these patients often have compromised health with a poor quality of life. Renal transplantation offers a viable treatment option for those inborn errors of metabolism characterized by primary renal damage caused by dysfunction of a mutated protein, as in cystinuria. In this case, the indication to renal transplantation makes it possible to overcome the specific enzyme defect. However this option remains valid even when the genetic defect is expressed systemically and renal involvement is just one of the clinical manifestations of the disease, as in Anderson-Fabry disease, cystinosis, hereditary amyloidosis and primary hyperoxaluria. In these conditions, renal transplantation is combined with the liver (primary hyperoxaluria) or cardiac transplant (familial amyloidosis) improving the quality and life expectancy of patients.

Left ventricular mass and cardiac function in a population of children with chronic kidney disease

BACKGROUND

Cardiovascular disease (CVD) is a common cause of morbidity and mortality in children with chronic kidney disease (CKD). Left ventricular hypertrophy (LVH) and diastolic dysfunction (LVDD) are early markers. The aims of this study were to evaluate (1) LVH and LVDD, using both conventional echocardiographic evaluation and Tissue Doppler Imaging (TDI), and (2) the correlation between cardiac disease and possible risk factors, in children with CKD.

METHODS

The study cohort comprised 34 paediatric patients with CKD and 34 healthy children (mean ± standard deviation: age 9 ± 4.6 and 8.2 ± 4.3 years, respectively). Thirteen (38 %) patients were in CKD stage 2, 15 (44 %) in stage 3 and six (18 %) in stage 4-5. LVH was defined as a left ventricular mass index (LVMI) of >95th percentile (38 g/h(2.7)).

RESULTS

Left ventricular hypertrophy was present in 13 patients (38 %). Diastolic function evaluated with TDI (E'/A' = early/late diastolic myocardial velocity) worsened with the reduction of glomerular filtration rate (p = 0.020). There was a positive correlation between LVMI and body mass index-standard deviation score (p = 0.020) and a negative correlation between E'/A' and serum phosphorus and calcium levels and their respective product (p = 0.004, p = 0.017, p < 0.001). The relaxation index E' was reduced in 68 % of patients.

CONCLUSION

Based on our results, TDI is a simple procedure and would appear to be a more accurate diagnostic tool than conventional echocardiography in the early diagnosis of LVDD.

Different guidelines for imaging after first UTI in febrile infants: yield, cost, and radiation

OBJECTIVE

To evaluate the yield, economic, and radiation costs of 5 diagnostic algorithms compared with a protocol where all tests are performed (ultrasonography scan, cystography, and late technetium(99)dimercaptosuccinic acid scan) in children after the first febrile urinary tract infections.

METHODS

A total of 304 children, 2 to 36 months of age, who completed the diagnostic follow-up (ultrasonography, cystourethrography, and acute and late technetium(99)dimercaptosuccinic acid scans) of a randomized controlled trial (Italian Renal Infection Study 1) were eligible. The guidelines applied to this cohort in a retrospective simulation were: Melbourne Royal Children's Hospital, National Institute of Clinical Excellence (NICE), top down approach, American Academy of Pediatrics (AAP), and Italian Society of Pediatric Nephrology. Primary outcomes were the yield of abnormal tests for each diagnostic protocol; secondary outcomes were the economic and radiation costs.

RESULTS

Vesicoureteral reflux (VUR) was identified in 66 (22%) children and a parenchymal scarring was identified in 45 (15%). For detection of VUR (47/66) and scarring (45/45), the top down approach showed the highest sensitivity (76% and 100%, respectively) but also the highest economic and radiation costs (€52 268. 624 mSv). NICE (19/66) and AAP (18/66) had the highest specificities for VUR (90%) and the Italian Society of Pediatric Nephrology had the highest specificity (20/45) for scars (86%). NICE would have been the least costly (€26 838) and AAP would have resulted in the least radiation exposure (42 mSv).

CONCLUSIONS

There is no ideal diagnostic protocol following a first febrile urinary tract infection. An aggressive protocol has a high sensitivity for detecting VUR and scarring but carries high financial and radiation costs with questionable benefit.

Non-viral infections in children after renal transplantation

Renal transplantation has long been recognised as the gold standard treatment for children with end-stage renal failure. There has been an improvement over the years in patient and renal allograft survival because of improved immunosuppression, surgical techniques and living kidney donation. Despite reduced acute allograft rejection rates, non-viral infections continue to be a serious complication for paediatric renal transplant recipients (RTR). The risk of infections in RTR is determined by the pre-transplantation immunisation status, post-transplant exposure to potential pathogens and the amount of immunosuppression. The greatest risk of life-threatening and Cytomegalovirus infections is during the first 6 months post-transplant owing to a high immunosuppressive burden. The potential sources of bacterial infections are donor derived, transplant medium fluid, peritoneal and haemodialysis catheter and transplant ureteric stent. Urinary tract infections are frequent in patients with lower urinary tract dysfunction and can result in renal allograft damage. This review outlines the incidence, timing, risk factors, prevention and treatment of non-viral infections in paediatric RTR by critically reviewing current immunosuppressive regimens, their risk-benefit ratio in order to optimise renal allograft survival with reduced rates of rejection and infectious complications.

Growth hormone treatment started in the first year of life in infants with chronic renal failure

Infants with chronic renal failure (CRF) are at high risk of experiencing severe growth retardation. We report a study of 12 infants with CRF who have been treated with recombinant human growth hormone (rhGH) since the age of 0.5 +/- 0.3 years. A control group comprised 15 infants with less severe CRF who were being treated during the same period, but who did not receive rhGH. Despite the infants in the rhGH group had more severe renal failure, they grew at least as well as those in the control group and experienced catch-up growth that started earlier and was more sustained; they also gained more weight. Between the age of 0.5 and 2.5 years, the height standard deviation score (HtSDS) improved from -2.0 +/- 1.2 to -0.9 +/- 0.9 in the rhGH group (p < 0.005) and from -1.6 +/- 1.6 to -1.0 +/- 1.9 in the control group (p=non significant, n.s.). The average gain in HtSDS was +1.1 +/- 0.8 in the treated group and +0.6 +/- 1.4 in the control group (p = n.s.). During the same period, the weight SDS improved from -2.2 +/- 0.9 to -0.6 +/- 1.2 (p < 0.005) and from -1.9 +/- 1.2 to -1.3 +/- 1.2 (p=n.s.) in the treatment and control groups, respectively. Nutritional intake was similar in both groups, while parathyroid hormone levels tended to increase, although not significantly, after rhGH treatment (p=n.s.). The results of this pilot study suggest that very early treatment with rhGH in patients with early-onset CRF may improve growth.

Hearing loss in Turner syndrome: results of a multicentric study

The purpose of this article was to evaluate otological diseases in 173 patients (pts) with Turner syndrome (TS).

STUDY DESIGN

One hundred and seventy-three pts, mean chronological age (CA) 12+/-6.2 yr. Patients were submitted to different therapies: GH, estrogen therapy (EE), no therapy (no tx). Seventy-nine pts (CA 11 yr) had no otological diseases. Conductive hearing loss (CHL) occurred in 38.7% (CA 11 yr) and otoscopy was: persistent secretory otitis media in 55.2%, chronic otitis media in 10.4%, pars flaccida retraction pocket in 19.4%, mostly bilateral. Cholesteatoma was present in 15%. Sensorineurinal hearing loss (SNHL) occurred in 15.6% (CA 16 yr), 11 of whom were affected by high tone loss, and 15 by loss in midfrequencies (dip between 0.5-3 kHz), bilateral in 93%. Degree of hearing loss (HL) was mild [20-40 decibel hearing level (dBHL)] in 15%, moderate (45-60 dBHL) in 31%, severe (65-80 dBHL) in 8%, profound (dBHL>85) in 2%. We found a significant association between CHL and karyotype 45, X (p<0.025), congenital cranio-facial abnormalities, prevalently with low-set ears (p<0.04), narrow and/or high arched palate (p<0.018), and micrognathia (p<0.004). Our study confirms that the high prevalence of middle ear infections and CHL in TS are probably due to growth disturbances of the structures from the first and second branchial arches. We did not find any association between EE, GH, and HL. We recommend a regular audiological follow-up, especially during childhood, to prevent important middle ear anatomic sequele and to identify HL at an early stage, as the impact on social functioning may be significant.

Glomerulocystic kidney disease in hypomelanosis of Ito

Hypomelanosis of Ito (incontinentia pigmenti type I) was first described as a disorder characterized by unusual unilateral or bilateral cutaneous macular hypopigmented whorls, streaks and patches. Subsequently, neurologic, skeletal and ocular involvement were described. Kidney involvement has been reported only exceptionally. Here, we describe the case of a male infant with hypomelanosis of Ito with a prenatal diagnosis of bilateral enlargement of the kidneys, decreased corticomedullary differentiation and cysts located in the cortical and subcapsular regions. These findings were confirmed postnatally. The skin examination showed hypopigmented linear and round diffuse lesions located on the right leg and the arms. Ophthalmological examination showed anterior capsular and posterior subcapsular cataract of the left eye. Renal biopsy was characteristic of glomerulocystic kidney disease, whereas the skin biopsy confirmed the clinical diagnosis of hypomelanosis of Ito. Four other cases of kidney disease in hypomelanosis of Ito have been reported, including two cases characterized by cystic renal changes, indicating that gene abnormalities that cause hypomelanosis of Ito may also impair normal renal development, causing renal cystic changes.

Gonadoblastoma in Turner syndrome and Y-chromosome-derived material

The identification of Y-chromosome material is important in females with Ullrich-Turner syndrome (UTS) due to the risk of developing gonadoblastoma or other gonadal tumors. There is controversy regarding the frequency of the Y-chromosome-derived material and the occurrence of gonadoblastoma in these patients. The aim of our study was to evaluate a large number of patients with UTS, followed before and during the pubertal age for the prevalence of Y-chromosome derived material, the occurrence of gonadoblastoma, and the incidence of possible neoplastic degeneration. An unselected series of 171 patients with UTS (1-34 years old), diagnosed cytogenetically, was studied for Y-chromosome markers (SRY and Y-centromeric DYZ3 repeats). The follow-up was of 2-22 years; 101 of these patients were followed during pubertal age. Y-chromosome material was found in 14 patients (8%): 12 of these were gonadectomized (2.8-25.9 years). A gonadoblastoma was detected in four patients under 16 years of age: in two, Y-material was detected only at molecular analysis (at conventional cytogenetic analysis, one was included in the 45,X group and one in the X + mar group) and one had also an immature teratoma and an endodermal sinus carcinoma. The prevalence of gonadoblastoma in our series of gonadectomized UTS patients with Y-positive material was of 33.3% (4/12). Our data suggest that the age of appearance and the possibility of malignant degeneration of gonadoblastoma can occur early in life. These patients, in particular those with 45,X or a marker chromosome may benefit from molecular screening to detect the presence of Y-chromosome material; PCR is a rapid and inexpensive technique. At the moment, laparoscopy and preventive gonadectomy performed as soon as possible remain the procedures of choice for patients with UTS, when Y-chromosome has been identified, as we are still unable to predict a future malignant evolution of gonadoblastoma.

Effects of exogenous propylene on softening, glycosidase, and pectinmethylesterase activity during postharvest ripening of apricots

Apricots (Prunus armeniaca L. cv. Boccuccia spinosa) picked at the commercial ripening stage [soluble solids content (SSC) 12.6%] were left to reach full ripening in continuously humidified air at 20 degrees C. Changes in the rate of ethylene production, firmness, soluble solids concentration, and titratable acidity were measured. The alpha-D- and beta-D-glucosidases, alpha-L-arabinofuranosidase, alpha-D- and beta-D-galactosidases, beta-D-xylosidase, and alpha-D-mannosidase activities were assayed. To evaluate the influence of ethylene on glycosidase activity, propylene (500 microL x L(-1)) was applied to apricots for 24 and 48 h. In apricots ripened in air, ethylene production increased on the first day and exhibited a typical climacteric pattern. Good edible quality was reached in 5 days when SSC was at least 14% and acidity was between 1.1 and 1.2% (% malic acid). During postharvest ripening, alpha-L-arabinofuranosidase activity increased from 1.9 to 11.6 nkat until day 7. alpha-D-Galactosidase, alpha-D-mannosidase, and beta-D-galactosidase activity increased continuously but at a lower rate. beta-D-Xylosidase activity also increased, but the level of activity was lower than the other glycosidases assayed. Pectinmethylesterase (PME) decreased during the postharvest ripening, and propylene enhanced this pattern, by stimulating ethylene production. Even the activities of alpha-L-arabinofuranosidase, beta-D-xylosidase, alpha-D-mannosidase, and beta-D-galactosidase were greatly stimulated by the propylene treatment, which consequently induced rapid softening of the fruits.

Vis-NIR measurement of soluble solids in cherry and apricot by PLS regression and wavelength selection

Experimental results are presented on the use of partial least squares (PLS) regression and wavelength selection for the definition of models for visible-near-infrared (Vis-NIR) evaluation of soluble solids content in fruits. First, the relatively easy to deal with-but still not studied in the literature-case of cherry fruit is presented in detail. By using a very simple selection scheme, involving the subsampling of the spectral interval from 600 to 1100 nm with a fixed step, accurate models were found, consistently showing very favorable combinations of SEC and SEP values, in the 0. 50 degrees Brix range for a total variation of about 15 degrees Brix. Apricot fruit represented a more difficult species, and wavelengths to be included in the calibration had to be individually selected for the best results. Nevertheless, parsimonious models could be found, including a total of 38 spectral lines and leading to SEP values at the 0.75 degrees Brix level.

Avascular necrosis of the trapezoid bone

A case of idiopathic avascular necrosis of the right trapezoid is presented. The aetiology was not clear. Treatment consisted of bone curettage, autologous bone graft and revascularization with a dorsal metacarpal artery.