Percentage of overweight is overestimated in children of short stature.

BACKGROUND: The prevalence of overweight and obesity has increased, not just in adults but also in children. In Japan, the percentage of overweight (POW) is widely used for the estimation and assessment of percentage body fat (PBF) for children. We examine whether there is a difference between normal height and short stature children in terms of the relationship between POW and PBF. METHODS: A total of 321 children of normal height (163 boys, 158 girls) and 106 children with short stature (78 boys, 28 girls) were assessed according to sex. Percentage of overweight was used to represent the degree of obesity. The PBF of the total body was examined by dual energy X-ray absorptiometry. RESULTS: According to their PBF, normal height subjects of both sexes were classified as obese if they had a POW of more than 20%. However, short-stature subjects of both sexes were not classified as obese until the boys had a POW of 40%, and girls had a POW of 35%, respectively. Thus, overweight or obesity is overestimated in short stature children in both males and females with the rule "POW above 20% is recognized as obesity." CONCLUSIONS: Percentage of overweight is commonly considered as a good surrogate measure for determining overweight and obesity in children of both sexes. However, this study has clarified that body fat accumulation is overestimated in children with short stature when using the POW measurement.

Evaluation of uric acid levels, thyroid function, and anthropometric parameters in Japanese children with Down syndrome.

Down syndrome, caused by trisomy 21, is characterized by congenital abnormalities as well as mental retardation. From the neonatal stage through adolescence, patients with Down syndrome often have several complications. Thus, it is important to attain knowledge of the prevalence of these comorbidities in children with Down syndrome. We, therefore, evaluated the biochemical data, thyroid function, and anthropometric parameters, and analyzed the association among them in Japanese children and early adolescents with Down syndrome. There was no difference in the prevalence of obesity and overweight between boys and girls. The level of uric acid was higher in boys than in girls. Moreover, the prevalence of hyperuricemia was also higher in boys than in girls (approximately 32% and 10%, respectively). The prevalence of subclinical hypothyroidism in children with Down syndrome was approximately 20%, with no significant sex differences. The levels of uric acid and dehydroepiandrosterone-sulfate were positively associated with age, while the levels of thyroid-stimulating hormone and free thyroxine had a negative association with age. Overall, children with Down syndrome, exhibit a higher incidence of hyperuricemia. Therefore, uric acid levels, as well as thyroid function, from childhood to early adulthood should be monitored in this patient cohort.

Relationship between asymmetric dimethylarginine in umbilical cord plasma and birth weight follows a U-shaped curve.

Asymmetric dimethylarginine (ADMA) is a nonselective nitric oxide (NO) synthase inhibitor associated with cardiovascular and metabolic disorders. NO regulates placental blood flow, which plays an important role in fetal growth. Many epidemiological studies have disclosed that restricted fetal growth is associated with an increased risk of insulin resistance in adult life. We studied the relationship between ADMA in cord blood and birth size. Nine small for gestational age (SGA) and 32 appropriate for gestational age (AGA) infants were studied. Their cord plasma ADMA, insulin, insulin-like growth factor-1 (IGF-1), and adipocytokine levels were determined using enzyme-linked immunosorbent assays. The relationship between birth weight and ADMA levels followed a U-shaped curve rather than inverse linear associations expected over a full range of birth weight distribution. ADMA positively correlated with birth weight in the AGA group (p<0.001, R=0.590), and inversely correlated with birth weight in the SGA group (p<0.05, R=-0.741). ADMA inversely correlated with adiponectin (p<0.05, R=-0.289) and quantitative insulin sensitivity check index (QUICKI) (p<0.05, R=-0.294) in all subjects, and did not correlate with nitrogen oxides (NOX). Insulin, IGF-1, leptin, adiponectin and QUICKI were lower in the SGA than the AGA group. Plasma ADMA levels in cord blood may be a marker of fetal growth and insulin resistance.

Decreased undercarboxylated osteocalcin in children with type 2 diabetes mellitus.

BACKGROUND: Osteocalcin (OC) is a bone-specific protein secreted by osteoblasts and often used as a bone formation biomarker. OC undergoes post-translational carboxylation to yield carboxylated osteocalcin (Gla-OC) and undercarboxylated osteocalcin (uc-OC) molecules. The aim of this study was to explore the association between bone and glucose metabolism by evaluating OC, ionized cations, and markers of glucose metabolism in children with obesity and type 2 diabetes mellitus (DM2). METHODS: The subjects were nine children with DM2 [six males, three females; age 15.7±4.1 years; duration of disease 3.2±1.2 years], 18 children with simple obesity [12 males, six females; age 12.6±4.1 years], and 12 controls [eight males, four females; age 12.3±3.2 years]. Serum Gla-OC and uc-OC levels were determined using an enzyme-linked immunosorbent assay (ELISA). RESULTS: Patients with DM2 (0.65±0.46 ng/mL), but not with obesity (1.11±0.55 ng/mL), had lower uc-OC levels than controls (1.25±0.49 ng/mL). Serum uc-OC was negatively correlated with mean serum glucose levels (r=-0.447, p=0.013) and hemoglobin A1c (HbA1c) (r=-0.455, p=0.012) in all subjects. Serum Gla-OC was correlated with serum alkaline phosphatase (r=0.601, p<0.001) and inorganic phosphorus (r=0.686, p<0.001), yet negatively correlated with age (r=-0.383, p=0.030). Mean serum ionized magnesium was lower in DM2 subjects than in controls. Mean serum ionized calcium was higher in obese subjects than in controls. In all subjects, mean serum ionized magnesium was negatively correlated with mean serum glucose levels. CONCLUSIONS: Osteoblast-derived protein OC, especially uc-OC, may have a role in the pathophysiology of diabetes by being associated with blood glucose homeostasis.

Asymmetric dimethylarginine is negatively correlated with hyperglycemia in children.

Asymmetric dimethylarginine (ADMA) is a nonselective nitric oxide (NO) synthase inhibitor associated with cardiovascular and metabolic disorders. In several prospective and cross-sectional studies, ADMA has evolved as a marker of cardiovascular risk. However, there is limited information on this serum marker in young people, particularly in those with obesity, type 1 diabetes (DM1) and type 2 diabetes (DM2). We investigated ADMA concentrations in children and adolescents with hyperglycemia as compared with healthy age- and sex-matched individuals. The subjects were 21 simple obesity [male 13, female 8; aged 11.7±4.3 years], 18 with DM1 [male 4, female 14; aged 12.9±4.2 years, duration of disease 3.4±2.1 years], 10 with DM2 [male 5, female 5; aged 13.9±3.4 years, duration of disease 2.8±1.4 years] and 21 controls [male 12, female 9; aged 11.1±2.7 years]. ADMA levels were analyzed in a cross-sectional study. Concentrations of serum ADMA were determined using an enzyme-linked immunosorbent assay. Circulating levels of ADMA were significantly lower in subjects with DM1, DM2 or obesity. In all subjects, ADMA levels were inversely correlated with glycated hemoglobin A1c concentrations (r=-0.401, p=0.0003) and serum glucose levels (r=-0.341, p=0.0023). Low circulating ADMA levels are directly associated with glucose levels, suggesting that ADMA production is suppressed in childhood in order to compensate and protect vasculopathy due to hyperglycemia.

A fatal case of infantile malignant osteopetrosis complicated by pulmonary arterial hypertension after hematopoietic stem cell transplantation.

Infantile malignant osteopetrosis (IMO) is a rare and fatal autosomal recessive condition characterized by a generalized increased in bone density. Hematopoietic stem cell transplantation (HSCT) is the only effective and rational therapy with achieving long-term disease-free survival. However, complications with HSCT for IMO remain unclear. Here we describe a male infant with IMO, carrying two novel mutations in the T-cell immune regulator 1 (TCIRG1) gene. The TCIRG1 gene encodes the a3 subunit of vacuolar H(+)-ATPase that plays an essential role in the resorptive function of osteoclasts. Direct sequencing of all 20 exons of the TCIRG1 gene revealed a single nucleotide change in exon 11 (c1305 G > T), which causes the substitution of Asp (GAT) for Glu (GAG) at position 435, and a two-nucleotide deletion in exon 16 (c1952-1953 del CA), causing a frame-shift mutation. However, the functional consequence of each mutation remains to be determined. Allogeneic HSCT was performed in the patient at the age of nine months. Donor engraftment was achieved, and abnormal bone metabolism and extramedullary hematopoiesis were corrected. Graft-versus-host disease was mild (grade I). However, the patient died of complication of pulmonary arterial hypertension at seven months after the HSCT. Postmortem examination revealed prominent vascular wall thickening of the pulmonary artery and macrophage infiltration to alveoli. It should be noted that a patient with IMO has a risk for pulmonary arterial hypertension, and the evaluation of pulmonary arterial flow should be included in the assessment of each patient with IMO even after HSCT.

A common signaling pathway is activated in erythroid cells expressing high levels of fetal hemoglobin: a potential role for cAMP-elevating agents in ß-globin disorders.

BACKGROUND: Although erythroid cells prepared from fetal liver, cord blood, or blood from ß-thalassemia patients are known to express fetal hemoglobin at high levels, the underlying mechanisms remain elusive. We previously showed that cyclic nucleotides such as cAMP and cGMP induce fetal hemoglobin expression in primary erythroid cells. Here we report that cAMP signaling contributes to high-level fetal hemoglobin expression in erythroid cells prepared from cord blood and ß-thalassemia. METHODS: The status of the cAMP signaling pathway was investigated using primary erythroid cells prepared from cord blood and the mononuclear cells of patients with ß-thalassemia; erythroid cells from adult bone marrow mononuclear cells served as the control. RESULTS: We found that intracellular cAMP levels were higher in erythroid cells from cord blood and ß-thalassemia than from adult bone marrow. Protein kinase A activity levels and cAMP-response element binding protein phosphorylation were higher in erythroid cells from cord blood or ß-thalassemia than in adult bone marrow progenitors. Mitogen-activated protein kinase pathways, which play a role in fetal hemoglobin expression, were not consistently activated in cord blood or ß-thalassemia erythroid cells. When cAMP signaling was activated in adult erythroid cells, fetal hemoglobin was induced at high levels and associated with reduced expression of BCL11A, a silencer of the ß-globin gene. CONCLUSION: These results suggest that activated cAMP signaling may be a common mechanism among erythroid cells with high fetal hemoglobin levels, in part because of downregulation of BCL11A. Activation of the cAMP signaling pathway with cAMP-elevating agents may prove to be an important signaling mechanism to reactivate fetal hemoglobin expression in erythroid cells.

Measurement of tongue-artificial nipple contact force in infants with sucking difficulties.

Infants are known to suckle and ingest breast milk by wrapping the tongue around a nipple, writhing the tongue, and pressing the nipple. However, the dynamic mechanisms of tongue movement are still obscure, and factors related to sucking difficulties of infants are not well understood. We developed an artificial nipple installed with small cantilever-type sensors and directly measured the force applied on the nipple by the tongue. Small force sensors were arranged within the artificial nipple in a two-dimensional matrix of 3 × 2 to measure the force at 6 points. Subjects were 20 healthy infants (Group A) and 5 infants who had difficulty sucking (Group B). The latter could not breastfeed well and were fed from bottles or tubes. Informed consent was provided by the parents or guardians. The measured maximum force at the tip of the nipple was 1.4 ± 0.4 N and 1.2 ± 0.3 N (mean ± SD) in Groups A and B, respectively. At the base of the nipple, the maximum force recorded was 0.8 ± 0.5 N and 0.3 ± 0.3 N (mean ± SD), respectively, showing a statistically significant difference (p<0.05). The sucking period was 0.6 ± 0.1 s (mean ± SD) in both groups. The difference in time necessary to reach the maximum forces between the sensors at the tip and base was 39.7 ± 28.8 ms (mean ± SD) and 37.2 ± 75.9 ms in Groups A and B, respectively.

Intracellular magnesium of obese and type 2 diabetes mellitus children.

INTRODUCTION: Magnesium is a critical cofactor in numerous enzymatic reactions. Diabetic patients and obese subjects are often reported to have intracellular magnesium ([Mg(2+)](i)) deficiency. We studied the change of [Mg(2+)](i) in obese children and children with type 2 diabetes mellitus (DM2) after educational intervention or treatment. METHODS: A total of 25 subjects were included: 13 with simple obesity (10 male, 3 female; mean age 16±8 years, intervention period 1.0±0.6 years), 12 with DM2 (8 male, 4 female; mean age 15±3 years, medication period 1.1±0.7 years), and 16 controls (8 male, 8 female; mean age 17±7 years). By using a fluorescent probe, mag-fura-2, we examined the basal and insulin-stimulated [Mg(2+)](i) of platelets in the blood. Plasma leptin, ghrelin, adiponectin, and resistin levels were determined with the use of enzyme-linked immunosorbent assay (ELISA). RESULTS: Mean basal [Mg(2+)](i) was lower in the obesity (160±65 µmol/L) and DM2 groups (140±30 µmol/L) compared with the control group (330±28 µmol/L). The elevated [Mg(2+)](i) after insulin stimulation was also lower in these two groups (420±140 µmol/L, and 330±70 µmol/L, respectively) compared with the control group (690±270 µmol/L). In the DM2 group, the basal [Mg(2+)](i) was significantly increased after treatment, while in the obesity group, stimulated [Mg(2+)](i) was increased after intervention. CONCLUSION: Platelet [Mg(2+)](i) increased after intervention in children with obesity or DM2.

Cerebral blood flow monitoring using a novel laser Doppler flowmeter in asphyxiated infants.

BACKGROUND: The aim of the present study was to investigate the role of early changes in cerebral blood flow (CBF) predicting the severity of neurological outcome in asphyxiated infants. METHOD: Serial monitoring of CBF was performed using a newly developed laser Doppler flowmeter (LDF) in parallel with conventional hemodynamic monitoring, such as mean arterial blood pressure (mABP) or heart rate (HR) in 11 asphyxiated infants (five infants with neurological sequelae and six infants without sequelae) during the first 4 days of life. Psychomotor development was followed up to 20 months. RESULTS: No differences in average CBF, mABP, average HR, or Apgar scores were found between infants with neurological sequelae and those without (P > 0.1). Significant difference was found only in average stability index during the first 48 h of life (SI48), defined as a coefficient of variation of CBF during the corresponding period (P= 0.04). An SI48 > or = 0.24 had positive predictive value of 100% for neurological sequelae while that <0.24 had a negative predictive value of 66.7%. CONCLUSION: SI48, an average stability index of CBF during the first 48 h of life, can be a useful index to predict neurological outcome in asphyxiated infants.

Expression of the gamma-globin gene is sustained by the cAMP-dependent pathway in beta-thalassaemia.

The present study found that the cyclic adenosine monophosphate (cAMP)-dependent pathway efficiently induced gamma-globin expression in adult erythroblasts, and this pathway plays a role in gamma-globin gene (HBG) expression in beta-thalassaemia. Expression of HBG mRNA increased to about 46% of non-HBA mRNA in adult erythroblasts treated with forskolin, while a cyclic guanosine monophosphate (cGMP) analogue induced HBG mRNA to levels <20% of non-HBA mRNA. In patients with beta-thalassaemia intermedia, cAMP levels were elevated in both red blood cells and nucleated erythroblasts but no consistent elevation was found with cGMP levels. The transcription factor cAMP response element binding protein (CREB) was phosphorylated in nucleated erythroblasts and its phosphorylation levels correlated with HBG mRNA levels of the patients. Other signalling molecules, such as mitogen-activated protein kinases and signal transducers and activators of transcription proteins, were phosphorylated at variable levels and showed no correlations with the HBG mRNA levels. Plasma levels of cytokines, such as erythropoietin, stem cell factor and transforming growth factor-beta were increased in patients, and these cytokines induced both HBG mRNA expression and CREB phosphorylation. These results demonstrate that the cAMP-dependent pathway, the activity of which is augmented by multiple cytokines, plays a role in regulating HBG expression in beta-thalassaemia.

cAMP differentially regulates gamma-globin gene expression in erythroleukemic cells and primary erythroblasts through c-Myb expression.

Our previous studies demonstrated roles of cyclic nucleotides in gamma-globin gene expression. We recently found that, upon activation of the cAMP pathway, expression of the gamma-globin gene is inhibited in K562 cells but induced in adult erythroblasts. Here we show that c-Myb, a proto-oncogene product that plays a role in cell growth and differentiation, is involved in the cAMP-mediated differential regulation of gamma-globin gene expression in K562 cells and primary erythroblasts. Our studies found that c-Myb is expressed at a high level in K562 cells compared to primary erythroblasts, and that c-Myb expression is further increased following the treatment with forskolin, an adenylate cyclase activator. The induction of gamma-globin gene expression was also inhibited in K562 cells by raising the levels of c-Myb expression. Importantly, forskolin-induced erythroid differentiation in K562 cells, as determined by the expression of glycophorins and CD71, suggesting that high-level expression of c-Myb may not be sufficient to inhibit the differentiation of erythroid cells. In contrast, c-Myb was not expressed in adult erythroblasts treated with forskolin and primary erythroblasts may lack the c-Myb-mediated inhibitory mechanism for gamma-globin gene expression. Together, these results show that the cAMP pathway blocks gamma-globin gene expression in K562 cells by increasing c-Myb expression and c-Myb plays a role in defining the mode of response of the gamma-globin gene to fetal hemoglobin inducers in erythroid cells.

Negative regulation of gamma-globin gene expression by cyclic AMP-dependent pathway in erythroid cells.

OBJECTIVE: Fetal hemoglobin inducers such as hemin, butyrate, and hydroxyurea stimulate gamma-globin gene expression by activating the cyclic GMP (cGMP)-dependent pathway. Although cGMP activates the cyclic AMP (cAMP)-dependent pathway by suppressing cGMP-inhibited phosphodiesterase 3 (PDE3), the effects of the cAMP-dependent pathway on gamma-globin gene expression are unknown. MATERIALS AND METHODS: The cAMP-dependent pathway was activated in K562 cells using the adenylate cyclase activator forskolin. Expression of gamma-globin mRNA was examined by primer extension, and transcriptional activity of the gamma-globin gene promoter was determined by reporter gene assays. RESULTS: PDE3 was expressed in K562 cells at a high level. The cAMP-dependent pathway was found to be activated in K562 cells in which the cGMP-dependent pathway was activated by hemin. Activation of the cAMP-dependent pathway by forskolin inhibited hemin-induced expression of gamma-globin mRNA and decreased transcriptional activity of the gamma-globin gene promoter. The levels of phosphorylation of mitogen-activated protein kinases (MAPKs) were not affected by the cAMP-dependent pathway. CONCLUSIONS: These results suggested that the cAMP-dependent pathway, which is independent of MAPK pathways, plays a negative role in gamma-globin gene expression in K562 cells. cAMP and cGMP may have differential roles in the regulation of gamma-globin gene expression in erythroid cells.