Mitsufumi Mayumi

Dysregulation of IL-13 production by cord blood CD4+ T cells is associated with the subsequent development of atopic disease in infants.

Early intervention strategies in allergic diseases will be dependent on identification of newborns at high risk for later development of atopic disease. In this cohort study of 106 neonates, we investigated whether cytokine production property and responsiveness to IL-12 of neonatal CD4+ T cells were associated with the subsequent development of atopic disease and whether a skewed cytokine production property was intrinsic to helper T cells. To exclude the effects of contaminating cells, highly purified cord blood CD4+ T cells were stimulated with anti-CD3 MAb and recombinant B7-2 molecule in the presence or absence of IL-12. Production of IL-13 and interferon-γ was determined by ELISA. The infants were assessed at 12 mo for the development of atopic diseases. CD4+ T cells of neonates who manifested allergic symptoms (atopic group) produced higher levels of IL-13 compared with those of the nonatopic group in both the presence and absence of IL-12. No significant difference was noted between the two groups with respect to interferon-γ production. Moreover, higher IL-13 production was also observed in neonates with chronic eczema than those with short-term eczema. Our data suggest that increased production of IL-13 by neonatal CD4+ T cells is a useful marker of newborns at high risk for subsequent development of atopic diseases and that an intrinsic abnormality of CD4+ T cell is associated with the pathogeneses of atopic disease, especially atopic dermatitis in infants.

Formation of Advanced Glycosylation End Products and Oxidative Stress in Young Patients with Type 1 Diabetes

Increased production of advanced glycosylation end products (AGEs) and augmented oxidative stress may contribute to vascular complications in diabetes. Little is known about the formation and accumulation of AGEs in young patients with type 1 diabetes. The aim of the present study was to investigate whether AGE production and oxidative stress are augmented in young patients with type 1 diabetes at early clinical stages of the disease. Urine samples of 38 patients with type 1 diabetes [mean age (±SD), 12.8 ± 4.5 y; diabetes duration, 5.7 ± 4.3 y; HbA1c, 8.0 ± 1.6%; urinary albumin excretion, 12.6 ± 14.4 mg/g creatinine (Cr)] and those of 60 age-matched healthy control subjects were assayed for AGEs, pentosidine and pyrraline, and markers of oxidative stress, 8-hydroxy-2′-deoxyguanosine (8-OHdG) and acrolein-lysine. Of these four markers, urinary concentrations of pentosidine, 8-OHdG, and acrolein-lysine were significantly higher in the patients with diabetes than in the healthy control subjects. For the patient group, pentosidine correlated significantly with 8-OHdG and acrolein-lysine, and pyrraline correlated significantly with acrolein-lysine. Urinary pentosidine, 8-OHdG, and acrolein-lysine but not pyrraline correlated significantly with urinary albumin excretion. Patients with microalbuminuria (≥15 mg/g Cr) showed significantly higher levels of all four markers than did normoalbuminuric patients and control subjects. The present study indicates that accumulation of AGEs, whose formation is closely linked to oxidative stress, and resultant endothelial dysfunction may start early in the course of type 1 diabetes. This means that the risk of vascular complications may be present at an early age and that the best possible glycemic control should be emphasized from the diagnosis of diabetes.

Bone mineral status in ambulatory pediatric patients on long‐term anti‐epileptic drug therapy

Background : For ambulatory pediatric outpatients, reports of abnormalities of bone metabolism associated with anti‐epileptic drugs are inconsistent and may be difficult to interpret.

Oxidant and antioxidant activities in childhood meningitis

Animal studies have provided substantial evidence for a key role of reactive oxygen species, nitric oxide and its related compounds in the complex pathophysiology of bacterial meningitis. However, there is little information on changes in the redox status in human meningitis. In the present study, we evaluated the redox status and oxidative stress in the central nervous system of children with meningitis. Oxidant and antioxidant activities were assessed from cerebrospinal fluid levels of acrolein-lysine adducts (a marker of lipid peroxidation), nitrite (a marker of nitric oxide production) and bilirubin derivatives (a marker of antioxidant activity of bilirubin). All these markers were several times higher in children during the early phase of bacterial meningitis compared with those of children without meningitis and patients with aseptic meningitis. In the bacterial meningitis group, the levels of bilirubin derivatives correlated significantly with those of acrolein-lysine adducts and nitrite. Acrolein-lysine adducts and nitrite decreased significantly as the patients started to respond to treatment but bilirubin derivatives remained elevated. In conclusion, our data indicate the enhancement of both oxidant and antioxidant activities in the central nervous system of children with early bacterial meningitis, but not in those with aseptic meningitis. Clinical and laboratory improvement may be associated with a decrease in oxidant activities in the central nervous system.

Evaluation of a urinary multi-parameter biomarker set for oxidative stress in children, adolescents and young adults

The involvement of reactive oxygen species (ROS) and oxidative stress in pediatric diseases is an important concern, but oxidative stress status in healthy young subjects and appropriate methods for its measurement remain unclear. This study evaluated a comprehensive set of urinary biomarkers for oxidative stress in healthy children, adolescents and young adults. Results show that urinary excretion of acrolein–lysine, 8-hydroxy-2′-deoxyguanosine (8-OHdG), nitrite/nitrate and pentosidine were highest in the youngest subjects and decreased to constant levels by early adolescence. Urinary acrolein–lysine, 8-OHdG, nitrite/nitrate and pentosidine showed significant inverse correlations with age, but pyrraline did not change significantly with age. No significant differences in biomarkers were apparent between males and females. Younger subjects grow rapidly and sustain immune activation, and are probably exposed to high concentrations of ROS and nitric oxide. Consequently, they are more vulnerable to oxidation of lipids, proteins, DNA and carbohydrates. Normal reported values in this study are a basis for future studies of disease mechanisms involving oxidative stress and for future trials using antioxidant therapies for oxidative stress-related diseases in the pediatric field.

Determination of asymmetric dimethylarginine, an endogenous nitric oxide synthase inhibitor, in umbilical blood.

Endothelial cells produce nitric oxide (NO), a potent vasodilator. Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of NO synthase. Little is known about the potential physiological roles of ADMA in a perinatal setting. This study measures concentrations of ADMA in umbilical blood using enzyme-linked immunosorbent assay and those of NO as nitrite/nitrate (NOx(-)) using the Griess assay. Their relationship to the degree of prematurity and maternal clinical condition is examined. Results show that ADMA concentrations in umbilical blood from control newborns were about twice as high as those of lactating women, healthy children, and healthy adults. Umbilical blood NOx(-) concentrations from control newborns were about half of those of lactating women, healthy children, and healthy adults. Consequently, the levels of ADMA relative to NOx(-) were about 4-fold higher in umbilical blood from control newborns than in blood from lactating women, healthy children, and healthy adults. Furthermore, the umbilical blood ADMA concentrations and the ratios of ADMA to NOx(-) in newborns were higher according to their birth prematurity and lower birth weight. The umbilical ADMA concentrations were independent of the delivery mode and maternal preeclampsia. We infer that the high ADMA levels play physiological roles in maintaining vascular tone and blood redistribution to vital organs during birth, thereby favoring the circulatory transition from fetal to neonatal life.

Meatus tightly covered by the prepuce is associated with urinary infection

Background : Almost all newborns have phimosis, which is known as one of the risk factors for urinary infection. The present study analyzed which specific prepuce conditions correlated with the development of febrile urinary infection in Japanese male infants.

Erythromycin Differentially Inhibits Lipopolysaccharide- or Poly(I:C)-Induced but Not Peptidoglycan-Induced Activation of Human Monocyte-Derived Dendritic Cells

Erythromycin (EM) has attracted attention because of its anti-inflammatory effect. Because dendritic cells (DCs) are the most potent APCs involved in numerous pathologic processes including innate immunity, we examined effects of EM on the activation of human DCs by pathogen-derived stimuli. Monocyte-derived DCs were pretreated with EM and subsequently stimulated with peptidoglycan, polyriboinosinic:polyribocytidylic acid (poly(I:C)), or LPS. The activation of DCs was assessed by surface molecule expression and cytokine production. To reveal the signaling pathways affected by EM, TLR expression, NF-κB, IFN regulatory factor-3, and AP-1 activation were examined. EM inhibited costimulatory molecule expression and cytokine production that was induced by poly(I:C) and LPS but not by peptidoglycan. EM pretreatment down- and up-regulated mRNA levels of TLR3 and TLR2, respectively, but did not affect that of TLR4. EM suppressed IFN regulatory factor-3 activation and IFN-β production but not AP-1 activation induced by poly(I:C) and LPS. The inhibitory effect of EM on NF-κB activation was observed only in poly(I:C)-stimulated DCs. EM selectively suppressed activation of DCs induced by LPS and poly(I:C) in different ways, suggesting that the immuno-modulating effects of EM depend on the nature of pathogens. These results might explain why EM prevents the virus-induced exacerbation in the chronic inflammatory respiratory diseases and give us the clue to design new drugs to treat these diseases.

Augmentation of NO-mediated vasodilation in metabolic acidosis.

Reduction of perivascular pH in acidemia produces hyporesponsiveness of vascular bed to vasoconstrictors. In the present study, we examined the effects of modest acidification on dilatory responses of isolated rat thoracic aorta. Acetylcholine produced endothelium-dependent relaxation in phenylephrine-precontracted aorta, which was markedly enhanced by acidification of Krebs-Henseleit solution from pH 7.4 to 7.0. A similar augmentation was observed in the relaxing responses to NO donors (SNP, SIN-1, SNAP), 8-Br-cGMP and NS-1619 (a putative K(Ca) channel opener and/or Ca channel inhibitor) in endothelium-denuded, phenylephrine-contracted aorta. However, papaverine-induced relaxation was not affected by the change in pH. At pH 7.4, the relaxing responses to acetylcholine and SNP were partially inhibited by charybdotoxin (K(Ca) channel inhibitor) but not glibenclamide (K(ATP) channel inhibitor), while at pH 7.0 the relaxation induced by either drug was not affected by K(+) channel inhibitors. Relaxation induced by 8-Br-cGMP or NS-1619 was not inhibited by charybdotoxin or glibenclamide. Acidification to pH 7.0 increased the cGMP production in response to acetylcholine in endothelium-intact aorta and to SNP in endothelium-denuded aorta. These results show that modest acidification augments NO-mediated relaxation in rat aorta, probably due to an enhancement of cGMP-dependent but K(+) channel-unrelated relaxation mechanisms.

Nitric oxide in septic and aseptic meningitis in children

To investigate the involvement of nitric oxide (NO) in childhood meningitis, we measured the concentrations of NO2- (a stable metabolite of NO) in serial samples of cerebrospinal fluid (CSF) from 11 children with septic and 7 with aseptic meningitis and 26 control patients without meningitis. The mean concentration of NO2- in samples obtained during the early stages of septic meningitis, but not aseptic meningitis, was significantly higher than in control samples. Clinical and laboratory improvement following administration of antibiotics and dexamethasone was associated with a fall in CSF [NO2-] to normal levels in these patients. CSF [NO2-] remained almost consistently within the normal range in patients with aseptic meningitis. Our findings indicate that NO production is enhanced in the CSF compartment of children with septic meningitis and support the hypothesis that NO is involved in the pathophysiology of septic meningitis.