Serum ferritin as an indicator of the development of encephalopathy in enterohemorrhagic Escherichia coli-induced hemolytic uremic syndrome.

OBJECTIVES: To investigate the diagnostic value of serum ferritin levels as a marker of disease activity and the development of encephalopathy in hemolytic uremic syndrome (HUS) induced by enterohemorrhagic Escherichia coli. METHODS: Twenty patients with HUS were studied. Serum ferritin levels were compared with clinical features and serum soluble tumor necrosis factor receptor (sTNFR) I and sTNFRII levels. Serum sTNFRI and sTNFRII levels were quantified by enzyme-linked immunosorbent assays. RESULTS: Serum ferritin levels were significantly elevated at the time of the diagnosis of HUS. Serum ferritin levels were significantly elevated in patients with encephalopathy compared to patients without encephalopathy. HUS patients with serum ferritin levels of >687.5 ng/ml were at high risk of encephalopathy. Serum ferritin levels were significantly positively correlated with serum sTNFRI and sTNFRII levels. CONCLUSIONS: Serum ferritin levels are a promising indicator of the development of encephalopathy in HUS.

Angiopoietin-1 and -2 as markers for disease severity in hemolytic uremic syndrome induced by enterohemorrhagic Escherichia coli.

BACKGROUND: Angiopoietin (Ang)-1 and -2 play important roles in maintaining vascular homeostasis. This study aimed to assess the roles of angiopoietin (Ang)-1 and -2 and to investigate the clinical significance of their serum levels in patients with hemolytic uremic syndrome (HUS) induced by enterohemorrhagic Escherichia coli (EHEC). METHODS: Twenty patients with HUS and 15 healthy controls were studied. Serum Ang-1 and Ang-2 levels were quantified using enzyme-linked immunosorbent assay. The results were compared with the clinical features of HUS. RESULTS: During the HUS phase, serum Ang-1 levels were significantly decreased, whereas serum Ang-2 levels and the Ang-2/Ang-1 ratio were significantly elevated. Compared with patients without encephalopathy, serum Ang-2 levels and Ang-2/Ang-1 ratio were significantly elevated in patients with encephalopathy. Patients with HUS and serum Ang-2 levels of >7061 pg/mL or Ang2/Ang1 ratios of >2.29 were at high risk of encephalopathy. Serum Ang-1 levels were significantly decreased in patients in the pre-HUS phase compared with those in healthy controls. CONCLUSION: Disruption of homeostasis of vascular endothelial function by Ang-1 and -2 may be closely associated with the development of HUS. Serum Ang-1 and -2 levels and the Ang-2/Ang-1 ratio may be promising indicators of disease activity in HUS and the development of encephalopathy.

The true distribution volume and bioavailability of mizoribine in children with chronic kidney disease.

BACKGROUND: Mizoribine (MZR) is used kidney transplant and various kidney diseases. However, few studies reported the association between pharmacokinetics and pharmacodynamics. The Pharmacokinetics Study Group for Pediatric Kidney Disease (PSPKD) used population pharmacokinetics (PPK) analysis and Bayesian analysis to investigate the usefulness of MZR. In this study, the fact that almost all MZR are excreted unchanged in urine was used to calculate its bioavailability (F) and true distribution volume (V d), and analyzed these correlation with age. METHODS: Ishida et al. reported a PPK analysis by the PSPKD. In the present study, 71 samples extracted from their study population of 105 pediatric chronic kidney disease patients aged between 1 and 20 years were investigated. The bioavailability was calculated by measuring total excreted MZR in 24 h urine samples, and this was compared to the oral dosage. The apparent distribution volume (V d/F) obtained from Bayesian analysis was then used to calculate true distribution volume (V d), and the correlation of each parameter with age was investigated. RESULTS: The median dose of MZR per weight was 5.17 mg/kg/day. Median bioavailability was 32.02%. Median V d per weight was 0.46 L/kg. There was a significant, weakly positive correlation between bioavailability and age (p = 0.026). There was also a significant, weakly negative correlation between V d per weight and age (p = 0.003). CONCLUSION: Bioavailability and V d per weight tended to decrease depending on age. The younger patient required larger dose required to obtain the maximum effect from MZR, and this is important for immunosuppressive therapy.

Female X-linked Alport syndrome with somatic mosaicism.

BACKGROUND: X-linked Alport syndrome (XLAS) is a progressive, hereditary nephropathy. Although males with XLAS usually develop end-stage renal disease before 30 years of age, some men show a milder phenotype and possess somatic mosaic variants of the type IV collagen α5 gene (COL4A5), with severity depending on variant frequencies. In females, somatic mosaic variants are rarely reported in XLAS, and it is not clear what determines severity. METHODS: Two females with somatic mosaic mutations in COL4A5 with variant frequencies of 17.9 and 22.1% were detected using the next-generation sequencing. One patient only had hematuria. The other, however, had moderate proteinuria, which is a severe phenotype for a female XLAS patient of her age. The molecular mechanisms for the severe phenotype were investigated by examining variant frequencies in urinary sediment cells and X chromosome inactivation patterns, and by looking for modifier variants in podocyte-related genes using the next-generation sequencing. RESULTS: The severe phenotype patient had a variant frequency of 36.6% in urinary sediment cells, which is not markedly high, nor did she show skewed X chromosome inactivation. However, she did have the heterozygous variant in COL4A3, which can affect severity. CONCLUSION: Factors determining severity in female XLAS patients remain unclear. One studied patient with the somatic variant in COL4A5 showed a severe phenotype without skewed X chromosome inactivation, which might be derived from digenic variants in COL4A3 and COL4A5. Further studies are required to determine molecular mechanisms behind female XLAS resulting in the severe phenotype.

Population pharmacokinetics of mizoribine in pediatric patients with kidney disease.

BACKGROUND: The present study aimed to obtain information enabling optimisation of the clinical effect of mizoribine (MZR) in pediatric patients with kidney disease. METHODS: A total of 105 pediatric patients with kidney disease treated at our institutions were enrolled. Kidney transplant patients were excluded. Population pharmacokinetic analysis of MZR was performed based on serum concentration data. Area under the curve from time zero to infinity (AUC∞) and maximal concentration (C max) were calculated by Bayesian analysis. RESULTS: In children, the appearance of MZR in the blood tended to be slower and the subsequent rise in blood concentration tended to be more sluggish, compared to healthy adults. Apparent volume of distribution and oral clearance were also higher in children compared to adults. A significant positive correlation was observed between patient age and AUC∞. There were significant differences of AUC∞ and C max by age group. No relationship was observed between the administration method of MZR and serum concentration. CONCLUSION: The pharmacokinetics of MZR was different in children compared to adults. To obtain the expected clinical efficacy, the regular MZR dosage schedule (2-3 mg/kg/day) might be insufficient for pediatric patients. In particular, younger patients might require a higher dosage of MZR per unit body weight.

Serum tau protein as a marker of disease activity in enterohemorrhagic Escherichia coli O111-induced hemolytic uremic syndrome.

Tau protein levels in cerebrospinal fluid (CSF) and serum are elevated in patients with various central nervous system diseases. We investigated whether serum tau protein levels are useful for predicting and assessing disease activity of acute encephalopathy (AE) in enterohemorrhagic Escherichia coli (EHEC) O111-induced hemolytic uremic syndrome (HUS; EHEC encephalopathy). Serum samples were obtained from 14 patients with EHEC O111/HUS, 20 patients with non-EHEC-related AE, and 20 age- and sex-matched healthy controls. CSF samples were obtained from 2 patients with EHEC encephalopathy and 20 patients with non-EHEC-related AE. Tau protein levels and levels of several proinflammatory cytokines were quantified by enzyme-linked immunosorbent assays. Results were compared with the clinical features of EHEC encephalopathy, including magnetic resonance image (MRI) findings. Serum tau levels in patients with EHEC encephalopathy were significantly elevated compared with those in patients with EHEC O111/HUS without encephalopathy, patients with non-EHEC-related AE, and healthy controls. The ratio of CSF tau levels to serum tau levels was >1.0 in all patients with non-EHEC-related AE but <1.0 in 2 patients with EHEC encephalopathy. Serum tau protein levels increased rapidly and markedly in patients with severe EHEC 0111/HUS and encephalopathy when HUS occurred, but were not elevated in mild patients, even in the HUS phase. Furthermore, changes in serum tau protein levels in patients with EHEC encephalopathy were consistent with abnormalities on brain MRI and were positively correlated with proinflammatory cytokine levels. Our results indicate that serum tau protein might be useful to predict and assess disease activity of EHEC encephalopathy.

Evaluation of right ventricular function using single-beat three-dimensional echocardiography in neonate.

Aim of our study was to evaluate right ventricular (RV) systolic function in neonate using newly developed single-beat three-dimensional echocardiography (sb3DE). We enrolled 15 healthy or premature neonates (0-53 days after birth). We scanned one beat full volume using Siemens ACUSON SC2000 (Siemens AG) echocardiography with 4Z1c full-volume transducer without ECG gating. RV end-diastolic volume (RVEDV) and RV end-systolic volume (RVESV) were computed with special software dedicated to analysis for RV volume. RV ejection fraction (RVEF) and RV stroke volume (3D-RVSV) were calculated. And RV stroke volume was also determined from the recordings of ejection blood flow velocity and diameter at the level of the pulmonary orifice in RV outflow tract (Doppler-RVSV). Tricuspid annular plane systolic excursion (TAPSE) was also measured by 2D echocardiography. RVEDV ranged from 5.1 to 10.7 ml (average 7.5 ml), RVESV ranged from 2.3 to 5.8 ml (average 3.9 ml). There was a good correlation between 3D-RVSV and Doppler-RVSV (r = 0.77). Bland-Altman plot revealed that 3D-RVSV became underestimation of an average of 1.78 ml compared to Doppler-RVSV. And TAPSE positively correlated with 3D-RVEF (r = 0.58, P = 0.038). Newly developed sb3DE enables us to perform three-dimensional acquisition of RV volume without ECG gating even in neonate. However, 3D-RVSV currently tends to be underestimated in neonatal measurement.

Impairment of Left Ventricular Longitudinal Contraction is Associated with Serum Brain Natriuretic Peptide Concentration in Patients with Acute-Phase Kawasaki Disease.

It is well known that brain natriuretic peptide (BNP) is elevated in the acute phase of Kawasaki disease (KD). We hypothesized that mitral annular plane systolic excursion (MAPSE) could identify LV dysfunction in the acute phase of KD. Fifty patients with KD were enrolled in this study. BNP sampling and an echocardiographic study were performed just before and after intravenous immunoglobulin administration. MAPSE was measured in M-mode in the apical four-chamber view. The %MAPSE was calculated as the MAPSE measured in the acute phase divided by that measured in the convalescent phase. We compared the acute and the convalescent phases of KD. The values of the MAPSE were significantly reduced (45 out of 50 patients) during the acute phase and immediately recovered in the convalescent phase (10.0 ± 1.9 vs. 12.7 ± 1.9 mm, P < 0.0001). Of the parameters tested, %MAPSE was the only echocardiographic parameter that was associated with Log-BNP. Additionally, %MAPSE had a significant negative correlation with Log-BNP (r = -0.45, P < 0.0039). Longitudinal LV contraction is impaired in the acute phase of KD, but it immediately recovers in the convalescent phase. Measuring the longitudinal LV contractility should be essential for evaluating LV function in the acute phase of KD, and MAPSE is useful for this evaluation.

Z-values of tricuspid annular plane systolic excursion in Japanese children.

BACKGROUND: The aim of this study was to establish growth-related standard values and z-values for tricuspid annular plane systolic excursion (TAPSE) for Japanese children. METHOD: We examined 953 consecutive healthy children and adolescents, ranging from newborn to 22.7 years of age (mean age, 4.4 ± 4.0 years). TAPSE was measured as the longitudinal tricuspid valve annular motion from the apex on M-mode echocardiography. The right ventricular (RV) stroke volume (RVSV) divided by the body surface area (RVSV/BSA) was used as an independent indicator of body size. RVSV was determined from the recordings of the ejection blood flow velocity and the diameter at the level of the pulmonary orifice in the RV outflow tract. RESULTS: TAPSE had positive correlations with age and BSA, ranging from 6.0 to 31.4 mm (mean, 19.1 ± 4.4 mm). The z-values ranged from -3.63 to 3.17. There was no significant difference in TAPSE between the genders (male, 19.0 ± 4.6 mm; female, 19.1 ± 4.2 mm). The z-values positively correlated with RVSV/BSA. CONCLUSIONS: Growth-related normal TAPSE was studied in healthy Japanese children to obtain the TAPSE z-value. TAPSE z-value is one of the parameters that can be used to assess RV systolic function independent of body size.

Cytokine profiles of patients with enterohemorrhagic Escherichia coli O111-induced hemolytic-uremic syndrome.

Proinflammatory cytokines are related to the pathogenesis of enterohemorrhagic Escherichia coli (EHEC) infection and hemolytic-uremic syndrome (HUS). We assessed the kinetics of the release of cytokines such as neopterin, interleukin (IL)-6, IL-8 and tumour necrosis factor (TNF)-α and the soluble forms of type I and II TNF receptors during EHEC O111-induced HUS (EHEC O111/HUS). Fourteen patients with EHEC O111/HUS were enrolled in this study. Serum concentrations of all cytokines other than TNF-α were significantly elevated in patients with severe HUS compared with those in patients with mild HUS. Although serum concentrations of TNF-α were not significantly higher in patients with severe HUS, most patients with acute encephalopathy showed elevated TNF-α levels. Serum concentrations of these cytokines rapidly and markedly increased, and massive hypercytokinaemia developed 1 day before the diagnosis of HUS in patients with severe HUS. Changes in the number of white blood cells and concentration of serum lactate dehydrogenase were significantly larger between the onset of hemorrhagic colitis and the time of the diagnosis of HUS in patients with severe HUS compared with those in patients with mild HUS. Proinflammatory cytokines play an important role in the pathogenesis of EHEC infection and development of severe complications, including HUS and encephalopathy. Monitoring the cytokine profile may be useful for assessing disease activity of EHEC O111 infections.

Survey of pediatric ward hospitalization due to respiratory syncytial virus infection after the introduction of palivizumab to high-risk infants in Japan.

BACKGROUND: Respiratory syncytial virus (RSV) infection is a major cause of hospitalization during the winter among infants and young children. In 2002 palivizumab was introduced to high-risk infants for RSV hospitalization in Japan. It is important to characterize the hospitalized children due to RSV infection after the introduction of palivizumab. METHODS: A survey was conducted to collect the data from the hospitalized children at 12 participating hospitals during the winter of 2007. RESULTS: From October 2007 through April 2008, 8163 children were admitted to participating hospitals, with RSV infection accounting for 811 of those hospitalizations. Mean age in children with RSV infection at hospitalization was 12.4 ± 12.7 months, and children under 24 months of age accounted for 86.4%. The mean gestational age of those at birth was 38.0 ± 2.6 weeks, with 82.4% of the children born at term. Palivizumab was administered in 24 cases of RSV infection, while there were 28 patients who were not treated with palivizumab, even though they met the indication for palivizumab. Death, in a total of five cases, occurred in children who were not treated with palivizumab. CONCLUSIONS: Palivizumab has been widely used in high-risk infants who were covered by health insurance, and most of the hospitalized children with RSV infection in the study hospitals were not treated with palivizumab.

Evaluation of limited sampling designs to estimate maximal concentration and area under the curve of mizoribine in pediatric patients with renal disease.

The aim of this study was to evaluate limited sampling designs to estimate the maximal concentration (C(max)) and area under the curve (AUC) of mizoribine in pediatric patients with renal disease. We utilized 48 serum mizoribine concentration profiles obtained from the full (6-point) sampling pharmacokinetic test, and estimated 48 individual C(max) and AUC values accurately with Bayesian analysis using the full sampling data. We then developed limited sampling models (LSM) for C(max) and AUC using 1-4 serum mizoribine concentration data points. The C(max) and AUC estimation performance of the Bayesian and LSM analysis was fairly good in the 3-point (2, 3, and 6 hr after the dose) sampling design. In addition, the C(max) estimation performance of the Bayesian and LSM analysis deteriorated only marginally even in the 1-point (3 hr) sampling design. On the other hand, the AUC estimation performance seemed to be inadequate in the 1-point (3 hr) sampling design; however, it improved markedly in the 2-point (3 and 6 hr) sampling design. These findings suggested that the 1-point (3 hr) sampling design is promising for approximate C(max) estimation, but that the 2-point (3 and 6 hr) sampling design is preferable to estimate the AUC of mizoribine.

Distinct cytokine profiles of systemic-onset juvenile idiopathic arthritis-associated macrophage activation syndrome with particular emphasis on the role of interleukin-18 in its pathogenesis.

OBJECTIVES: To compare the pro-inflammatory cytokine profiles and the cytokine kinetics in patients with secondary macrophage activation syndrome (MAS) due to systemic-onset juvenile idiopathic arthritis (s-JIA) and in both active and inactive disease states of s-JIA (but no MAS), with those demonstrated in EBV-induced haemophagocytic lymphohistiocytosis (HLH) and Kawasaki disease (KD), and to investigate the significance of IL-18 in the pathogenesis of s-JIA. METHODS: Five patients with MAS complicating s-JIA (MAS/s-JIA), 10 with HLH due to EBV infection (EBV-HLH), 22 with KD and 28 healthy controls were analysed. Cytokine concentrations (IL-18, IL-6, neopterin and TNF-alpha receptor Types I and II) were quantified in serum by ELISA. Results were compared with clinical features of MAS/s-JIA, including ferritin concentrations. RESULTS: Serum IL-18 concentrations in MAS/s-JIA patients were significantly higher than those in EBV-HLH or KD patients (P < 0.05). Serum IL-6 concentrations in KD patients were significantly higher than those in EBV-HLH or MAS/s-JIA patients. Serum neopterin concentrations in EBV-HLH patients were significantly higher than those in MAS/s-JIA or KD patients. Serum IL-18 correlated positively with the following measurements of disease activity: CRP, ferritin, lactate dehydrogenase and other cytokines (P < 0.05). Serum concentrations of IL-18 in s-JIA patients remained elevated in the inactive phase of disease, whereas clinical parameters and other cytokines normalized. CONCLUSIONS: IL-18 may be an important mediator in s-JIA. Although serum Il-18 concentrations correlated with markers of the disease activity, IL-18 concentrations remained elevated even when other markers of disease activity normalized. Serum IL-18 concentration may be a promising indicator of the disease activity. The cytokine release pattern in MAS/HLH is different among patients with different aetiologies. Monitoring the cytokine profile, including IL-18, may be useful for differentiation of MAS/HLH and evaluation of disease activity in s-JIA.