Ozan Ozkaya

Etiology and outcome of acute kidney injury in children.

The aim of this prospective, multicenter study was to define the etiology and clinical features of acute kidney injury (AKI) in a pediatric patient cohort and to determine prognostic factors. Pediatric-modified RIFLE (pRIFLE) criteria were used to classify AKI. The patient cohort comprised 472 pediatric patients (264xa0males, 208 females), of whom 32.6% were newborns (median age 3xa0days, range 1–24 days), and 67.4% were children agedu2009>1xa0month (median 2.99xa0years, range 1xa0month–18xa0years). The most common medical conditions were prematurity (42.2%) and congenital heart disease (CHD, 11.7%) in newborns, and malignancy (12.9%) and CHD (12.3%) in children agedu2009>1xa0month. Hypoxic/ischemic injury and sepsis were the leading causes of AKI in both age groups. Dialysis was performed in 30.3% of newborns and 33.6% of children agedu2009>1xa0month. Mortality was higher in the newborns (42.6 vs. 27.9%; pu2009<u20090.005). Stepwise multiple regression analysis revealed the major independent risk factors to be mechanical ventilation [relative risk (RR) 17.31, 95% confidence interval (95% CI) 4.88–61.42], hypervolemia (RR 12.90, 95% CI 1.97–84.37), CHD (RR 9.85, 95% CI 2.08–46.60), and metabolic acidosis (RR 7.64, 95% CI 2.90–20.15) in newborns and mechanical ventilation (RR 8.73, 95% CI 3.95–19.29), hypoxia (RR 5.35, 95% CI 2.26–12.67), and intrinsic AKI (RR 4.91, 95% CI 2.04–11.78) in childrenu2009 aged >1xa0month.

Polymorphisms in the Vitamin D Receptor Gene and the Risk of Calcium Nephrolithiasis in Children

OBJECTIVEnPolymorphism in the Vitamin D Receptor (VDR) gene has recently been reported to be associated with calcium metabolism disorders. This study was conducted to investigate the association of VDR gene polymorphism with the risk of calcium nephrolithiasis.nnnMETHODSnWe investigated the VDR ApaI, BsmI and TaqI polymorphisms, in relation to serum calcium, phosphate, intact parathyroid hormone and 1.25(OH)(2)D(3) in 64 hypercalciuric stone-forming children and 90 healthy children. DNA was isolated from peripheral blood, and genotyping was performed with PCR-based methods.nnnRESULTSnThe frequency of ApaI AA genotype was significantly higher in the children with calcium nephrolithiasis than the controls (chi(2)=9.5; p=0.008). The distribution of BsmI and TaqI genotypes in stone-forming patients was similar to those in the control group. There was a significant association between TaqI TT genotype and the strength of the family history. The patients with TT genotype were observed to have a 8 times more risk than patients with Tt/tt genotype for recurrent stone episodes (OR 8, 95%CI 1.61-39.6).nnnCONCLUSIONnVDR genotype determination may provide a tool to identify individuals who are at a risk for calcium nephrolithiasis.

Renin-angiotensin system gene polymorphisms: association with susceptibility to Henoch-Schonlein purpura and renal involvement.

The clinical course of Henoch–Schönlein Purpura (HSP) in children is variable, with some patients having a much more rapidly progressing course than others. We investigated whether polymorphisms of the renin–angiotensin system (RAS) genes are involved in HSP. Three RAS genotypes were examined in 114 children with HSP and in 164 healthy children: the angiotensin I converting enzyme (ACE) insertion/deletion polymorphism, the M235T mutation in the angiotensinogen gene (Agt), and the A1166C in the angiotensin II type I receptor (AT1R) gene. Significant differences were observed between HSP patients and control group in the frequency of ACE and Agt genotypes (p=0.004 and p=0.003, respectively). The TT genotype of Agt gene was associated with a 3.5-fold increased risk for Henoch–Schönlein nephritis (HSN) compared with the MM/MT genotype (odds ratio, 3.5; 95% confidence interval, 1.2–10.4). There was a trend to a higher prevalence of the TT genotype of the Agt gene among patients with nephrotic range proteinuria when compared to the patients with mild proteinuria, although the difference did not reach a statistical significance. The results of this study suggest that polymorphisms of ACE gene and Agt gene likely influence the risk of developing HSP. However, among the three genes of the RAS studies, only Agt gene was associated with the susceptibility to HSN. RAS gene polymorphisms studied are not associated with the presence of nephrotic range proteinuria. Additional studies are warranted to verify the correlation between RAS gene polymorphisms and susceptibility to HSP.

Carbamazepine poisoning managed with haemodialysis and haemoperfusion in three adolescents

Carbamazepine is a widely used antiepileptic agent. Accidental or suicidal overdose in children is not uncommon. Acute toxicity is associated with seizures, coma, arrhythmias and death in severe cases. Here we report three adolescents with carbamzepine overdose, two managed with standard low‐flux haemodialysis and one with charcoal haemoperfusion. Our report emphasizes that haemodialysis might be a cheaper and easier alternative for carbamazepine overdose in milder cases, with fewer side‐effects than haemoperfusion.

Nitric oxide in Henoch-Schönlein purpura.

Objective : To assess the value of nitric oxide (NO) production on the disease activity in children with Henoch-Schönlein purpura (HSP) by measuring serum nitrate levels and urinary nitrate excretion as an indicator for NO production. Methods : The study group consisted of 25 patients and 20 healthy children. We measured serum nitrate, urinary excretion of nitrate, and CRP levels in the acute phase and after remission. Results : Serum nitrate levels in the acute phase of the disease were found to be increased compared to the remission phase (28.67 - 10.3 mmol/l, 14.16 - 2.02 mmol/l) (p<0.001) and the control group (13.15 - 2.28 mmol/l) (p<0.001). Urinary nitrate excretion in the acute phase of the patients (15.32 - 9 mmol/mg) was increased compared to that in the remission phase (8.26 - 4.3 mmol/mg) (p=0.016) and in the control group (7.24 - 4.9 mmol/mg) (p<0.01). Conclusion : Serum NO and urinary nitrate excretion were found to be elevated in patients with HSP and this increase was associated with activation of the disease rather than its severity. These findings suggest a role for NO in the pathogenesis of HSP, but nitric oxide in HSP should be further studied in order to elucidate the pathophysiology of the disease

Vitamin D receptor gene polymorphism in hypercalciuric children

Idiopathic hypercalciuria is a complex disease resulting from an interaction between environmental and genetic factors. Recently, the relationship between vitamin D receptor (VDR) alleles and calcium homeostasis has been investigated. This study was conducted to explore the association of VDR gene polymorphism with the risk of absorptive hypercalciuria (AH). We investigated the VDR gene polymorphisms, ApaI, BsmI, and TaqI, in relation to intact parathormone (PTH), osteocalcin, and 25-hydroxyvitamin D in 80 children (42 males, 38 girls) with AH and in 86 healthy children without hypercalciuria. A significant difference in the ApaI genotype was observed between the AH group and the control group (χ2=7.21, P=0.027). The AA genotype was associated with a 3.5-fold increased risk for idiopathic hypercalciuria compared with the Aa/aa genotype (odds ratio 3.5, 95% confidence interval 1.1–11). The BsmI and TaqI polymorphisms did not show any significant association with AH. Serum osteocalcin levels were significantly higher in the group with the AA genotype compared with those with the Aa or aa genotype (P=0.02, P=0.05, respectively). The results indicate that the ApaI AA genotype of the VDR gene is not only associated with AH but is also related to differences in serum osteocalcin.

Plasma and urine nitric oxide levels in healthy Turkish children

Nitric oxide (NO) is an important messenger molecule with a wide range of actions in virtually all cell systems and organs. In kidneys it participates in glomerular and medullary hemodynamics, tubuloglomerular feed-back, renin secretion, and extracellular fluid balance. Although the role of NO in regulating renal function in adults is well-established, it has recently been suggested that NO has a more critical role in maintaining basal renal blood flow and glomerular filtration rate (GFR) in the developing kidney. NO is rapidly metabolized to the stable end products nitrite and nitrate, which are more slowly excreted into the urine. Thus these metabolites can be recommended as useful markers of endogenous NO synthase activity, despite limited data about age-related changes in in-vivo NO production. The aims of this study were to determine age-related normal reference values of serum and urinary NO metabolites and to assess the probable relationship between these metabolites and the GFR. Normal levels of NO end products in blood and urine of 296 healthy children (117 female, 179 male) between the ages of 0 and 16 were investigated, as was whether these values change with age. Serum and urinary nitrate levels did not differ according to sex. Serum nitrate levels are higher in younger children, especially in the newborn period, and decrease with age. Nitrate levels in urine are higher in younger children with a peak in infancy (1 month to 1xa0year) and decrease with age. It was demonstrated that this decrease in serum and urinary nitrate levels with age parallels the increase in GFR. In conclusion, urinary NO products may be an indirect marker of serum NO levels and NO might have an important regulatory function both in the maintenance of renal function and in the maturation of the developing kidneys.

Physical function, muscle strength and muscle mass in children on peritoneal dialysis.

The aim of this study was to examine the physical function and muscle strength of children on peritoneal dialysis (PD) and to assess whether the muscle structure alterations influence physical function and muscle strength in these children. Twenty-two children on PD and 16 healthy children were enrolled into the study. A 6-min walk distance and gait speed tests were used to evaluate physical performance. Quadriceps muscle strength (QMS) was measured with a hand-held dynamometer. Magnetic resonance imaging was used to determine the cross-sectional area (CSA) and T2 signal intensity of the quadriceps muscle. Significant differences in the performance of these functional tests were found between PD patients and controls. Quadriceps muscle strength was significantly lower in PD patients than in controls. The CSA corrected for the body mass index (CSA/BMI) was not different between groups, whereas T2 signal intensity was significantly higher in PD patients than in the controls. Physical functioning tests and QMS had a close relationship with muscle CSA/BMI and with T2 signal intensity. In conclusion, along with the other previously documented mechanisms, increased fat in muscles may contribute to the decreased physical functioning and muscle strength in PD patients.

Cryptosporidiosis: A rare and severe infection in a pediatric renal transplant recipient

Acikgoz Y, Ozkaya O, Bek K, Genc G, Sensoy SG, Hokelek M. Cryptosporidiosis: A rare and severe infection in a pediatric renal transplant recipient.

Safety of inhaled corticosteroid therapy in young children with asthma

BACKGROUNDnPhysicians have had some reluctance to use inhaled corticosteroids in very young children with asthma because of the possible risks of adverse systemic effects.nnnOBJECTIVEnThe purpose of this study was to evaluate the effects of fluticasone propionate on growth and adrenocortical function in young children with asthma.nnnMETHODSnWe performed an open, prospective study for 24 weeks of 20 children with asthma, 2.5 to 5.0 years of age, who had received fluticasone by a large volume spacer at dosages ranging from 190.50 to 565.40 microg/m2 daily. Growth was evaluated by height standard deviation scores measured by a stadiometer. Adrenocortical function was evaluated twice in each child, before and after the study, by determining fasting serum cortisol concentrations at 8 AM and also at 30 and 60 minutes after adrenocorticotropic hormone stimulation. Posttreatment values of height standard deviation scores and fasting morning serum cortisol concentrations were compared with those of 18 age-matched children, who constituted the control group.nnnRESULTSnThe evaluation of mean +/- SEM (and range) of height standard deviation scores revealed a significant decrease from 0.44 +/- 0.27 (-1.46 to 2.22) to 0.28 +/- 0.26 (-1.51 to 2.07; P = 0.01) at week 18 and to 0.25 +/- 0.24 (-1.90 to 2.13; P = 0.04) at the week 24 in fluticasone-treated children. At the end of the treatment, however, height standard deviation scores of these children did not differ significantly (P = 0.35) from those of the control group. Delayed growth with medium-duration treatment was not associated with alterations in serum cortisol measurements, either at baseline or after stimulation. The mean fasting morning serum cortisol concentrations did not differ significantly between the fluticasone-treated patients and the control group.nnnCONCLUSIONSnSome concern prevails about the safety of medium- or long-term treatment with regularly inhaled corticosteroids in young children with asthma. The prepubertal growth may be delayed, but the effect on ultimate height remains uncertain in such children. Growth should be regularly monitored in children who begin inhaled corticosteroid therapy for mild persistent asthma at an age <5 years old.