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Biomedical subjects

J Feber

Publications and source records attributed to J Feber.

At least 19 recordsLinked to original sources
PubMed2006

Prevalence of complications in children with chronic kidney disease according to KDOQI.

The Kidney Disease Outcome and Quality Initiative (KDOQI) Group recommended guidelines for the monitoring and treatment of chronic kidney disease (CKD) in 2002. These recommendations were based on the prevalence of known complications as seen in adults. In children, the exact prevalence of these complications is unknown. We therefore conducted a cross-sectional study of 366 patients with CKD in a single center to analyze the prevalence of these complications across all stages of kidney disease. Patients were categorized to their KDOQI stage of CKD according to their estimated renal function as determined from serum cystatin C. Fifty seven percent of patients had CKD stage 1, 29.0% stage 2, 10.4% stage 3 and 4.1% stages 4+5. Uropathies (31%) were the most prevalent causes of CKD. Glomerular disease accounted for 27%. The overall prevalence of complications was as follows: hypertension 70.2%, anemia 36.6%, proteinuria 11.5%, and metabolic bone disease 16.9%. Metabolic bone disease and anemia occurred frequently, even with a glomerular filtration rate >60 ml/min/1.73 m2. Growth failure (11.5%) was also common and is not a component of the KDOQI guidelines for CKD in children. The prevalence of all complications increased with worsening stage of kidney disease (all P-values significant). In summary, this study supports the KDOQI guidelines in defining and staging CKD in children. This study also highlights the differences in the causes and complications that occur in CKD between adults and pediatrics. We recommend modification of the KDOQI guidelines for children to reflect the differences described in this paper.

Acidosis↗
PubMed2005

[What is new in pediatric nephrology?].

Recent advances in the knowledge of physiology, genetics, imaging, and therapeutics have lead to novel practical approaches in paediatric nephrology. Many inherited syndromes have been revisited in order to identify precise renal diseases at the molecular level. In addition, a large number of epidemiological studies and clinical trials have allowed guidelines and recommendations to be provided for chronic and end-stage renal failure, urinary tract infection, glomerular diseases, etc.

Child↗
PubMed2004

Ambulatory blood pressure monitoring in children after renal transplantation.

Arterial hypertension is a common complication in children after renal transplantation and the control of hypertension is often difficult. This retrospective investigates the prevalence and rate of control of hypertension using ambulatory blood pressure monitoring (ABPM) in 45 children (mean age 14.1 +/- 4.3 years, mean time after renal transplantation 2.2 +/- 2.7 years), all on cyclosporine or tacrolimus, azathioprine or mycophenolate mofetil plus daily steroids. The overall prevalence of hypertension was 82%. None of the transplanted children had normal blood pressure without antihypertensive therapy (ie, spontaneous normotension). Twenty percent of children had untreated hypertension, 18% had controlled hypertension, and 62% had uncontrolled hypertension. Prevalence of the nondipping phenomenon was 53%. The mean number of antihypertensive drugs (without diuretic monotherapy) in treated patients was 1.9 drugs per patient. The prevalence of arterial hypertension in children after renal transplantation is high and the control of hypertension is often unsatisfactorily low.

Adolescent↗
PubMed2003

Tissue HHV6 and 7 determination in pediatric solid organ recipients--a pilot study.

Herpes virus infections remain a major challenge in solid organ transplantation. HHV6 and 7 blood viral load was associated with pathology after renal transplantation. Little is known about the significance of tissue HHV6 and 7 infections. A total of 18 tissue biopsies (13 kidney, three GI and two BAL) from nine pediatric transplant patients (five kidney, two liver, one combined liver and kidney and one bone marrow transplant) were subjected to blood HHV6 IgG and IgM testing. In addition, tissue HHV6 and 7 semi-quantitative PCR analysis with subsequent detection by ELISA and quantitative methods were applied to the same samples. We also studied four native kidney biopsies of children with other kidney disease. The results of the biopsies were correlated with clinical data. Of the transplant patients, 78% were HHV6 IgG positive. Six of nine had a positive IgM on at least one occasion, however, only two of nine transplant patients were symptomatic with a mixed CMV/EBV septic picture of multi-organ failure. Only these two patients had a significant tissue viral load for HHV6. Additionally, a very significant tissue viral load for HHV6 was detected in an immunocompromised patient 3 wk after a roseola-like febrile illness. The HHV6 copies were 31, 88 and 206 per 10 microL of DNA, respectively. In the patient who also had the fourth positive ELISA for HHV6 PCR product, the Multiplex PCR and restriction enzyme assay on its PCR product revealed a significant contribution by HHV7, while the HHV6-B signal was rather weak. Significant tissue HHV6 loads can be found in tissue biopsies from organ recipients with significant illness and also in native kidneys after primary infection. This may explain the high prevalence of HHV6 in transplanted kidneys. Further studies on HHV6 and 7 using molecular techniques should be supported.

Adolescent↗
PubMed2002

Universal approach to pharmacokinetic monitoring of immunosuppressive agents in children.

Current data indicate that pharmacokinetic (PK) monitoring of cyclosporin microemulsion (CsA) should be performed using the 2-h concentration (C2), that tacrolimus (Tac) is commonly monitored using the trough level, and mycophenolate mofetil (MMF) should be monitored using the 1-h (C1), 2-h (C2) and 6-h (C6) concentrations. The three differing time-point requirements are cumbersome, and we aimed to develop universal guidelines for all three drugs using a large number of full PK profiles in children. One-hundred and twenty two stable pediatric patients, receiving either CsA (165 PK profiles, 69 patients, 24 with concomitant MMF) or Tac (122 PK profiles, 53 patients, 18 with MMF) were analyzed retrospectively. Pearson r for the CsA C2 was 0.90 [95% confidence interval(CI): 0.86-0.92], for Tac C2 r was 0.86 (95% CI: 0.80-0.90), and for MPA C2 r was 0.77 (95% CI: 0.68-0.83), respectively. For MPA, at least three time-points are required to accurately estimate the area under the concentration-time curve (AUC), and C1, C2 and C6 serve as best markers. Excellent AUC estimations could be obtained from a limited sampling strategy from C1, C2 and C6 or C0, C1, C2 and C4 with clinically acceptable errors for all three drugs. The AUC can be estimated with great precision by using an identical approach for all three drugs. Target AUCs for a given time-point after transplantation remain to be established.

Adolescent↗
PubMed2001

[Turner syndrome: overview of problems, present status, proposals for care and a protocol for monitoring in childhood, adolescence and adulthood].

BACKGROUND: Girls and adolescents with Turner syndrome (TS) usually receive intensive medical care in a multidisciplinary team, coordinated by paediatric endocrinologist. Majority of them are discharged from specialist clinics following the induction of puberty and attainment of final height. Patients with Turner syndrome have a reduced life expectancy, they are known to have multi-system impairments in addition to the short stature and to the absence of sexual development. Aim of this study is to propos a continuous follow-up by multidisciplinary team of physicians starting in childhood and following the discharge from the paediatric care. METHODS AND RESULTS: This paper highlights the medical and psychosocial problems associated with Turner syndrome in childhood, adolescence and in adulthood. Analysis of these problems served as a background to management strategy. CONCLUSIONS: Women with Turner syndrome are at risk of number of medical problems. Quality of their life and the life expectancy can be improved with increasing awareness to comorbities associated with Turner syndrome. Assisted reproduction technologies has recently offered a chance for pregnancy and delivery of a healthy child also to women with Turner syndrome. Therefore, long-term follow-up by multidisciplinary team of physicians knowledgeable about these medical problems is necessary. Introduction of a centralised system of systematic multidisciplinary approach to patients with Turner syndrome from childhood and adolescence to adulthood seems to be very important.

Adolescent↗
PubMed2001

Repeated ambulatory blood pressure monitoring in adolescents with mild hypertension.

The reproducibility of serial measurements of ambulatory blood pressure monitoring (ABPM) has not been well explored in children. We performed 24-h ABPM in 59 subjects (38 boys) aged 8-19 years with repeatedly elevated casual blood pressure (BP). According to the results of ABPM, the individuals were divided into a hypertensive group (mean 24-h systolic or diastolic BP >95th percentile for height, n=28) and a normotensive group (n=31). No antihypertensive agents were given. Both groups were reexamined after 1 year. In the hypertensive group, systolic and diastolic BP dropped significantly by an average of 2.1-4.5 mmHg when measured either during the daytime or over 24 h, but not at nighttime. In the normotensive group, only small BP changes were observed except for a significant increase in systolic BP at night. At the repeat examination after 1 year, 54% of the originally hypertensive subjects were defined as normotensive and 23% of the originally normotensive subjects as hypertensive. The study indicates that a single ABPM measurement is not sufficient for definitive classification of young individuals into hypertensives or normotensives.

Adolescent↗
PubMed2001

Body composition in children after renal transplantation.

This study examines changes in body composition after renal transplantation (Tx) in 16 children who underwent dual-energy X-ray absorptiometry examination within 6 months preceding Tx; the examination was then repeated every 6 to 12 months after Tx. Body composition was analyzed with regard to whole-body bone mineral content (BMC), lean body mass (LBM), and fat body mass (FBM). Median BMC decreased from the initial value of +0.98 standard deviation scores (SDS) to -0.55 SDS during the first 3 months after Tx, and a further decrease was noted at the end of month 6 (M6; -1.34 SDS) and M12 after Tx (-1.32 SDS). Improvement was observed during the second year after Tx (P for global changes < 0.0001). LBM and FBM also changed significantly during the 2 years after Tx (P = 0.006 and P = 0.0001, respectively). LBM decreased during the first 3 months after Tx (median change, 0.71 SDS) and remained less than 0 SDS in all but 4 patients. Median LBM did not decrease to less than -1 SDS during the entire study period. Conversely, median FBM increased by a median of 3.73 SDS during the first 3 months and remained elevated during the first 12 months after Tx, with a subsequent decrease at 2 years after Tx. No significant correlation was found between cumulative doses of prednisone and BMC, FBM, or LBM at any interval if absolute values were considered. However, relative changes in FBM correlated significantly with relative changes in prednisone cumulative doses.

Absorptiometry, Photon↗
PubMed2000

Bone mineral density in children after renal transplantation.

A successful kidney transplantation (Tx) offers good quality of life for children suffering from chronic renal failure. However, some metabolic abnormalities may not be corrected and may persist after Tx despite good graft function. Post-Tx bone disease seems to be a universal finding in adult Tx recipients, and is most probably related to steroids. Reports on bone mineral density (BMD) in children after renal Tx are not uniform. Recent studies suggest that BMD is normal when corrected for height. However, longitudinal studies show a transient decrease in BMD in the early post-Tx period. These controversial results raise the issue of the correct interpretation of dual-energy X-ray absorptiometry in children with stunted growth. Etiopathogenetic factors of the decreased BMD, preventive and therapeutic measures are discussed. In conclusion, the results of dual energy X-ray absorptiometry should be interpreted with caution, especially in children with disturbed growth.

Adult↗
PubMed2000

[Dual X-ray absorptiometry (DEXA) in children with chronic diseases].

Dual energy X-ray absorptiometry (DEXA) can be used for the measurement of bone density at the level of lumbar spine, whole body scan, and also for the measurement of bone mass content (BMC), lean body mass (LBM), and fat body mass (FBM). Although this method has been originally developed for the diagnosis and monitoring of osteoporosis in adults, it is used in children with chronic diseases like chronic renal failure, chronic gastrointestinal and rheumatological diseases. However, children with chronic disease often demonstrate statural growth disturbances and decreased growth velocity. Therefore, their actual height does not correspond to the actual chronological age. Normal values of DEXA for a given age are based on data from children with normal height. Interpretation of DEXA regardless of the actual height, which is usually stunted, may lead to false conclusions and wrong therapeutic attitudes. Thus, when interpreting results obtained in such patients a few transformations and calculations should be done.

Absorptiometry, Photon↗
PubMed2000

[Renal transplantation in children in the Czech Republic].

The aim of the study is to review results of pediatric renal transplantation in center in Prague, Czech Republic. Results are compared with the registry data from Europe and United States. Patients, who underwent RTx at the University Hospital Motol, Prague (Czech Republic) between 1977 and the end of 1999, were analyzed. Since 1977 128 Rtx from cadaveric donors were performed in children in mean age 12.8 +/- 4.1 years. In 1977-1987, patients were treated with prednisone and azathioprine, and since 1988, cyclosporine A, added to prednisone and azathioprine. Sequential quadruple immunosuppression was used only in few highly sensitized patients. Acute graft rejections were treated with methylprednisolone pulses, antithymocyte globulin and monoclonal antibodies OKT3, in selected cases. In 1988 and 1999 cyclosporine A was replaced by tacrolimus as initial immunosuppression in some patients. The number of Tx ranged between 5 and 13 per year. Patients and graft survival were significantly lower in the first time period 1977-1987 with a median patients 5-year survival rate of only 50% and graft survival 30%. In the last period (1988-1999) 5-year patients survival is 90% and 5-year graft survival is 68% (p = 0.01). Two cases of posttransplant lymphoproliferative disease were diagnosed so far. One of them died several months after RTx, the other received cytostatic therapy for Hodgkin tumor and graft function was maintained. Main causes of graft failure were chronic rejection followed by acute steroid resistant rejections, severe cytomegalovirus infections, noncompliance, vascular thrombosis, and recurrence of original disease.

Adolescent↗
PubMed1999

Combined liver-kidney transplantation in primary hyperoxaluria type 1.

Primary hyperoxaluria type 1 (PH1) is a rare autosomal recessive disorder characterised by an increased urinary excretion of calcium oxalate, leading to recurrent urolithiasis, nephrocalcinosis and accumulation of insoluble oxalate throughout the body (oxalosis) when the glomerular filtration rate falls to below 40-20 mL/min per 1.73 m(2). The disease is due to a functional defect of the liver-specific peroxisomal enzyme alanine: glyoxylate aminotransferase (AGT), the gene of which is located on chromosome 2q37.3. The diagnosis is based on increased urinary oxalate and glycollate, increased plasma oxalate and AGT measurement in a liver biopsy. AGT mistargeting may be investigated by immuno-electron microscopy and DNA analysis. End-stage renal failure is reached by the age of 15 years in 50% of PH1 patients and the overall death rate approximates 30%. The conservative treatment includes high fluid intake, pyridoxine and crystallisation inhibitors. Since the kidney is the main target of the disease, isolated kidney transplantation (Tx) has been proposed in association with vigorous peri-operative haemodialysis in an attempt to clear plasma oxalate at the time of Tx. However, because of a 100% recurrence rate, the average 3-year graft survival is 15%-25% in Europe, with a 5-10-year patient survival rate ranging from 10% to 50%. Since the liver is the only organ responsible for the detoxification of glyoxylate by AGT, deficient host liver removal is the first rationale for enzyme replacement therapy. Subsequent orthotopic liver Tx aims to supply the missing enzyme in its normal cellular and subcellular location and thus can be regarded as a form of gene therapy. Because of the usual spectrum of the disease, isolated liver Tx is limited to selected patients prior to having reached an advanced stage of chronic renal failure. Combined liver-kidney Tx has therefore become a conventional treatment for most PH1 patients: according to the European experience, patient survival approximates 80% at 5 years and 70% at 10 years. In addition, the renal function of survivors remains stable over time, between 40 and 60 mL/min per 1.73 m(2) after 5 to 10 years. In addition, liver Tx may allow the reversal of systemic storage disease (i.e. bone, heart, vessels, nerves) and provide valuable quality of life. Whatever the transplant strategy, the outcome is improved when patients are transplanted early in order to limit systemic oxalosis. According to the European experience, it appears that combined liver-kidney Tx is performed in PH1 patients with encouraging results, renal Tx alone has little role in the treatment of this disease, and liver Tx reverses the underlying metabolic defect and its clinical consequences.

Adolescent↗
PubMed1998

Body composition in children receiving recombinant human growth hormone after renal transplantation.

BACKGROUND: Recombinant human growth hormone (rhGH) is an anabolic hormone promoting protein synthesis in various tissues. Therefore, changes in body composition may be expected during rhGH treatment. METHODS: We studied changes in body composition during two years of rhGH treatment in 21 children after at least one year with a functioning renal transplant. The mean +/- SD age was 12.9+/-2.5 years at the start of rhGH therapy. A whole body, dual energy X-ray absorptiometry (DEXA) exam was performed before the initiation of rhGH therapy (T0), and was repeated at one and two year intervals after initiation of the therapy (T1 and T2, respectively). RESULTS: Lean body mass increased by a median of 0.48 SDS during the first year of treatment (P = 0.022), and the median increase during two years of therapy was 0.36 SDS (P = 0.061). On the contrary, the median fat body mass decreased by 2.17 SDS during the T0 to T1 period (P = 0.04) and by 1.99 SDS during the T0 to T2 period (P = 0.055). The index for fat body mass/lean body mass (FBM/LBM) decreased by a median of 5.3% during T0 to T1 (P < 0.001), however, a slower but still significant decrease by a median of 4.2% was noted at T2 (P < 0.05). Bone mass content did not change significantly during rhGH treatment. The medians in caloric and protein intakes were stable during rhGH treatment. CONCLUSION: A significant increase of lean body mass and a decrease of fat body mass was noted during rhGH therapy in children after renal transplantation.

Adolescent↗
PubMed1998

Estimation of peritoneal mass transport by three-pore model in children.

BACKGROUND: Computerized modeling is increasingly used to optimize the efficacy of peritoneal dialysis (PD). The Personal Dialysis Capacity (PDC) test is a new tool to model PD efficacy based on the three-pore model of peritoneal mass transport. We sought to evaluate (i) whether the PDC test is applicable to children on chronic PD, and (ii) whether the physiological mass transport coefficients defined in the three pore model are dependent on age or body size in childhood. METHODS: A validation study was performed in 32 pediatric chronic PD patients. Twenty tests were performed using a standard CAPD regimen, and 22 tests using a simplified automated PD (APD) protocol. Test accuracy and precision were evaluated by comparison of predicted with measured 24-hour dialysate clearances of urea, creatinine, beta2-microglobulin and albumin and ultrafiltration rates. Long-term reproducibility was assessed in 16 patients by repeated clearance studies after a median time interval of 10 weeks. RESULTS: While daily clearances of urea and creatinine were predicted with good precision and accuracy with both test protocols (concordance correlation coefficients 0.90 to 0.98, mean difference predicted-calculated -0.6 to +0.6 ml/min/1.73 m2), ultrafiltration rates were predicted more closely by the APD (r = 0.97) than by the CAPD test (0.80). Middle and large molecule clearances were predicted less precisely in both test settings (r = 0.48 to 0.83). Re-test reproducibility was slightly lower than the predictive precision observed in the original test (r = 0.80 to 0.91). The calculated total peritoneal pore area increased in absolute terms, decreased with body size when standardized to weight, and was independent of body size when normalized to body surface area. The body size-normalized fluid reabsorption rate was slightly increased in young infants compared to older children or adults. CONCLUSIONS: The PDC test permits to model peritoneal solute and water transport with remarkable precision in children of all age groups. While the peritoneal pore area is a linear function of body surface area, fluid reabsorption appears to be slightly increased in young infants.

Adolescent↗
PubMed1997

[Hereditary diseases causing kidney calculi].

Urolithiasis and/or nephrocalcinosis due to hereditary diseases are a rare event which must be kept in mind of physicians who take care of children (10 to 40% of all causes of lithiases) as well as of adults (less than 15% of all causes of lithiases) since a specific management is usually required. The most frequent inborn disorders are idiopathic hypercalciuria, distal tubular acidosis, cystinuria and hyperoxaluria. Stone formation is always secondary to an increased urine concentration of promotors, i.e. calcium, oxalate, phosphate, cystine, xanthine. One of the most informative diagnosis investigation is infrared spectrophotometry which can identify stone composition. When such a technique is not available, biochemical investigations should be adapted to both personal and family history. In addition to high fluid intake (2 to 3 L/m2/24 h) sometimes associated with alcalinisation, the management of hereditary stone disease requires specific procedure. In all cases, the long-term renal prognosis is related to both primary disease and therapeutic compliance.

Adult↗
PubMed1997

Body composition and physical performance in children after renal transplantation.

Body composition using standard anthropometric methods and dual-energy X-ray absorptiometry (DEXA) was determined in a cross-sectional study among 26 pediatric renal transplant recipients. At the same time, spiroergometry exam, pulmonary function tests, dynamometry and tremometry exams were performed in all patients. Fat body mass obtained by DEXA correlated inversely with maximal physical load during spiroergometry exam (r2 = 0.51, p = 0.0001). The study demonstrates good tolerance of increased physical load in children after renal transplantation. An inverse relationship was found between fat body mass and physical performance. Exercise training programs for children after renal transplantation are therefore suggested.

Absorptiometry, Photon↗
PubMed1996

Body composition in children with renal disease: use of dual energy X-ray absorptiometry.

Dual energy X-ray absorptiometry (DEXA) is a non-invasive accurate method which estimates bone mineral content and density (BMD), as well as fat (FM) and lean (LM) body mass. This method was used in control children in order to establish normal values for BMD of lumbar spine and whole body composition ¿logistic curves, general equation E = k+K/[1+ alpha exp(- beta A)]¿. In children with chronic renal failure (CRF), LM correlated with the urinary excretion of creatinine (r = 0.97, P = 0.0001) independently from glomerular filtration rate. However, the assessment of LM by DEXA must take into account the hydration level, since there is a positive correlation between fluid loss and reduction in LM in children on hemodialysis (r = 0.98, P = 0.0001). After renal transplantation, a significant loss of BMD (median -9.2%) was observed at 6 months which returned to 95% of pretransplant values by the end of the 1st year. Maximal changes in LM and FM occurred during the first 3 months (-7.8% and +7.2%, respectively) and may be due to steroids; these should be influenced by physical activity since FM correlated inversely with maximal oxygen consumption (r = 0.69, P = 0.0001). Recombinant growth hormone treatment could also increase LM and decrease FM, as shown in 9 patients. DEXA appears therefore to be a reliable method for evaluating therapeutic interventions affecting nutritional status in children with CRF.

Absorptiometry, Photon↗