Japanese Infants Research Articles

Emergence of Japanese infants' prosodic preferences in infant-directed vocabulary.

The article examines the role of infant-directed vocabulary (IDV) in infants language acquisition, specifically addressing the question of whether IDV forms that are not prominent in adult language may nonetheless be useful to the process of acquisition. Japanese IDV offers a good test case, as IDV characteristically takes a bisyllabic H(eavy)-L(ight) form that is rare in adult speech. In 5 experiments using the Headturn Preference Procedure (HPP), 8- to 10-month-old Japanese infants, but not 4- to 6-month-olds, were found to show a preference for bisyllabic H-L words over other types of words. These results demonstrate (a) that infants may develop a preference for a dominant prosodic form based on infant-directed speech, even when it is not a prominent characteristic of adult language; and perhaps more importantly, and (b) that infant-directed speech may provide a boost for a feature that could be useful for infants' acquisition of language even when it not prominent in adult language. (PsycINFO Database Record

Extracorporeal membrane oxygenation in 61 neonates: Single‐center experience

There have been few reports on the outcome of extracorporeal membrane oxygenation (ECMO) in newborn Japanese infants. A review was carried out of 61 neonates with ECMO between January 1995 and December 2015 at a single center. ECMO was used in neonates with oxygenation index >20 after conventional treatment. Background factors, such as etiology, vascular access mode (veno-venous [VV] or veno-arterial [VA]), number of days with ECMO, and early ECMO (within 24 h after birth), were analyzed in relation to outcome with respect to survival to hospital discharge (SHD). Survival to hospital discharge was achieved in 35 infants (57%), while the remaining 26 died during hospital stay. Gestational age at birth was significantly higher and number of days with ECMO was significantly lower in SHD infants compared with those with adverse outcome (median, 4.0 vs 5.5 days, respectively; P = 0.008). The SHD rate was significantly higher for those with VV than VA vascular access mode (78%, 18/23 vs 45%, 17/38, respectively; P = 0.016), and for those with than without early ECMO (72%, 28/39 vs 32%, 7/22, respectively; P = 0.003). The SHD rate was relatively high in neonates with meconium aspiration syndrome (86%, 12/14), persistent pulmonary hypertension associated with hypoxic ischemic encephalopathy (75%, 6/8), and emphysema (80%, 4/5). On stepwise logistic regression analysis two independent factors of SHD were identified: early ECMO (OR, 9.63; 95%CI: 2.47-37.6) and ECMO length <8 days (OR, 8.05; 95%CI: 1.94-33.5). Neonates with early ECMO and those with ECMO duration <8 days may benefit from ECMO with respect to SHD.

Relationship between copper and lipids and atherogenic indices soon after birth in Japanese preterm infants of 32-35 weeks.

Several studies have reported association of altered levels of lipids and some trace elements with risk factors for cardiovascular disease development in adulthood. Accordingly, the present study aimed to determine the relationship among the serum levels of copper (Cu), zinc (Zn), lipids, lipoproteins and apolipoproteins in preterm infants through an assessment of atherogenic indices shortly after birth. Blood samples were collected within 20 min of birth from 45 preterm infants with gestational ages ranging from 32 to 35 weeks. Serum Cu, Zn, total cholesterol (TC), low-density lipoprotein cholesterol (LDLc), high-density lipoprotein cholesterol (HDLc), apolipoprotein-A1 (apoA1) and apolipoprotein-B (apoB) levels were measured, and the TC/HDLc, LDLc/HDLc and apoB/apoA1 ratios were calculated. Upon determining the correlation between the levels of Cu, Zn and these indices of lipid metabolism, triglyceride (TG) and Cu were found to correlate negatively with birth weight (BW) and the standard deviation (s.d.) score for body weight. Furthermore, Cu levels correlated positively with the TG level and TC/HDLc, LDLc/HDLc and apoB/apoA1 ratios and negatively with the HDLc level and HDLc/apoA1 ratios. However, a stepwise multiple regression analysis indicated that the s.d. score for BW and TG level were significant independent determinants of the Cu level. In contrast, Zn did not correlate with any of these indices. In conclusion, intrauterine growth restriction and the TG level at birth influence Cu levels in preterm infants, whereas atherogenic indices do not affect this parameter.

Sensitive Quantitative Analysis of the Meconium Bacterial Microbiota in Healthy Term Infants Born Vaginally or by Cesarean Section

For decades, babies were thought to be born germ-free, but recent evidences suggest that they are already exposed to various bacteria in utero. However, the data on population levels of such pioneer gut bacteria, particularly in context to birth mode, is sparse. We herein aimed to quantify such bacteria from the meconium of 151 healthy term Japanese infants born vaginally or by C-section. Neonatal first meconium was obtained within 24–48 h of delivery; RNA was extracted and subjected to reverse-transcription-quantitative PCR using specific primers for Clostridium coccoides group, C. leptum subgroup, Bacteroides fragilis group, Atopobium cluster, Prevotella, Bifidobacterium, Lactobacillus, Enterococcus, Enterobacteriaceae, Staphylococcus, Enterococcus, Streptococcus, C. perfringens, and C. difficile. We detected several bacterial groups in both vaginally- and cesarean-born infants. B. fragilis group, Enterobacteriaceae, Enterococcus, Streptococcus, and Staphylococcus were detected in more than 50% of infants, with counts ranging from 105 to 108 cells/g sample. About 30–35% samples harbored Bifidobacterium and Lactobacillus (104–105 cells/g); whereas C. coccoides group, C. leptum subgroup and C. perfringens were detected in 10–20% infants (103–105 cells/g). Compared to vaginally-born babies, cesarean-born babies were significantly less often colonized with Lactobacillus genus (6% vs. 37%; P = 0.01) and Lactobacillus gasseri subgroup (6% vs. 31%; P = 0.04). Overall, seven Lactobacillus subgroups/species, i.e., L. gasseri subgroup, L. ruminis subgroup, L. casei subgroup, L. reuteri subgroup, L. sakei subgroup, L. plantarum subgroup, and L. brevis were detected in the samples from vaginally-born group, whereas only two members, i.e., L. gasseri subgroup and L. brevis were detected in the cesarean group. These data corroborate that several bacterial clades may already be present before birth in term infants’ gut. Further, lower detection rate of lactobacilli in cesarean-born babies suggests that the primary source of lactobacilli in infant gut is mainly from maternal vaginal and–to a lesser extent–anal microbiota during vaginal delivery, and that the colonization by some important Lactobacillus species is delayed in babies delivered via cesarean-section.

Early Introduction of Cooked Egg May Help Prevent Food Allergy in High-Risk Infants

Nearly 150 Japanese infants aged 4 to 5 months with atopic dermatitis who had not yet consumed hen's eggs were randomized to ingest a heated egg powder

Perceptual narrowing towards adult faces is a cross-cultural phenomenon in infancy: a behavioral and near-infrared spectroscopy study with Japanese infants.

Recent data showed that, in Caucasian infants, perceptual narrowing occurs for own‐race adult faces between 3 and 9 months of age, possibly as a consequence of the extensive amount of social and perceptual experience accumulated with caregivers and/or other adult individuals of the same race of the caregiver. The neural correlates of this developmental process remain unexplored, and it is currently unknown whether perceptual tuning towards adult faces can be extended to other cultures. To this end, in the current study we tested the ability of 3‐ and 9‐month‐old Japanese infants to discriminate among adult and infant Asian faces in a visual familiarization task (Experiment 1), and compared 9‐month‐olds’ cerebral hemodynamic responses to adult and infant faces as measured by near‐infrared spectroscopy (NIRS) (Experiment 2). Results showed that 3‐month‐olds exhibit above‐chance discrimination of adult and infant faces, whereas 9‐month‐olds discriminate adult faces but not infant faces (Experiment 1). Moreover, adult faces, but not infant faces, induced significant increases in hemodynamic responses in the right temporal areas of 9‐month‐old infants. Overall, our data suggest that perceptual narrowing towards adult faces is a cross‐cultural phenomenon occurring between 3 and 9 months of age, and translates by 9 months of age into a right‐hemispheric specialization in the processing of adult faces.

DEVELOPMENT OF AGE-SPECIFIC JAPANESE PHYSICAL PHANTOMS FOR DOSE EVALUATION IN INFANT CT EXAMINATIONS.

Secondary to the previous development of age-specific Japanese head phantoms, the authors designed Japanese torso phantoms for dose assessment in infant computed tomography (CT) examinations and completed a Japanese 3-y-old head-torso phantom. For design of age-specific torso phantoms (0, 0.5, 1 and 3 y old), anatomical structures were measured from CT images of Japanese infant patients. From the CT morphometry, it was found that rib cages of Japanese infants were smaller than those in Europeans and Americans. Radiophotoluminescence glass dosemeters were used for dose measurement of a 3-y-old head-torso phantom. To examine the validity of the developed phantom, organ and effective doses by the in-phantom dosimetry system were compared with simulation values in a web-based CT dose calculation system (WAZA-ARI). The differences in doses between the two systems were <20 % at the doses of organs within scan regions and effective doses in head, chest and abdominopelvic CT examinations.

Supplemental Material for Emergence of Japanese Infants’ Prosodic Preferences in Infant-Directed Vocabulary

Supplemental Material for Emergence of Japanese Infants’ Prosodic Preferences in Infant-Directed Vocabulary

Implicit association to infant faces: Genetics, early care experiences, and cultural factors influence caregiving propensities

Genetics, early experience, and culture shape caregiving, but it is still not clear how genetics, early experiences, and cultural factors might interact to influence specific caregiving propensities, such as adult responsiveness to infant cues. To address this gap, 80 Italian adults (50% M; 18–25 years) were (1) genotyped for two oxytocin receptor gene polymorphisms (rs53576 and rs2254298) and the serotonin transporter gene polymorphism (5-HTTLPR), which are implicated in parenting behaviour, (2) completed the Adult Parental Acceptance/Rejection Questionnaire to evaluate their recollections of parental behaviours toward them in childhood, and (3) were administered a Single Category Implicit Association Test to evaluate their implicit responses to faces of Italian infants, Japanese infants, and Italian adults. Analysis of implicit associations revealed that Italian infant faces were evaluated as most positive; participants in the rs53576 GG group had the most positive implicit associations to Italian infant faces; the serotonin polymorphism moderated the effect of early care experiences on adults’ implicit association to both Italian infant and adult female faces. Finally, 5-HTTLPR S carriers showed less positive implicit responses to Japanese infant faces. We conclude that adult in-group preference extends to in-group infant faces and that implicit responses to social cues are influenced by interactions of genetics, early care experiences, and cultural factors. These findings have implications for understanding processes that regulate adult caregiving.

Eosinophilia in infants with food protein-induced enterocolitis syndrome in Japan

BackgroundMany Japanese infants with food protein-induced enterocolitis syndrome (FPIES) show eosinophilia, which has been thought to be a characteristic of food protein-induced proctocolitis (FPIP). MethodsTo elucidate the characteristics of eosinophilia in Japanese FPIES patients, 113 infants with non-IgE-mediated gastrointestinal food allergy due to cow's milk were enrolled and classified into FPIES (n = 94) and FPIP (n = 19). ResultsThe percentage of peripheral blood eosinophils (Eo) was increased in most FPIES patients (median, 7.5%), which was comparable with that in FPIP patients (9.0%). Among FPIES patients, Eo was the highest in patients who had vomiting, bloody stool, and diarrhea simultaneously (12.9%) and lowest in patients with diarrhea alone (3.2%). Eo showed a significant positive correlation with the incidence of vomiting (Cramer's V = 0.31, p < 0.005) and bloody stool (Cramer's V = 0.34, p < 0.0005). A significant difference was found in Eo between early- (≤10 days, n = 56) and late-onset (>10 days, n = 38) FPIES (median, 9.8% vs. 5.4%; p < 0.005). IL-5 production by peripheral blood T cells stimulated with cow's milk protein in early-onset FPIES was significantly higher than that in late-onset FPIES (67.7 pg/mL vs. 12.5 pg/mL, p < 0.01), and showed a significant positive correlation with Eo (rs = 0.60, p < 0.01). ConclusionsThis study demonstrated two types of eosinophilia in Japanese FPIES infants: conspicuous and mild eosinophilia in early- and late-onset FPIES patients, respectively. Conspicuous eosinophilia in early-onset FPIES is suggested to be caused by abnormally high IL-5 production.

Serum biotin in Japanese children: Enzyme-linked immunosorbent assay measurement.

Biotin deficiency has been reported in Japanese infants fed special formulas for medical reasons, including those with milk allergy and congenital metabolic diseases, because these formulas contain little biotin. Serum biotin measurement is useful for diagnosing biotin deficiency. We applied a simple and rapid method to analyze serum biotin, and established normal ranges for children and adults. Serum biotin in 188 healthy Japanese children aged 0-4 years and in 25 healthy adults was analyzed using a Biotin ELISA Kit (immundiagnostik). The effects of various conditions on the measurement of serum biotin were also examined. Median biotin in children aged 0-4 years was 10.4 ng/dL (IQR, 7.9-13.4 ng/dL), and that in adults was 12.9 ng/dL (IQR, 10.8-15.8 ng/dL). Normal range was 4.7-22.0 ng/dL in children and 8.4-20.5 ng/dL in adults (calculated using two-sided 95%CI). Measurements obtained with this method were not affected by frozen storage, freeze-thaw, or hemolysis, indicating that serum biotin can be analyzed accurately under these conditions, with a possible application to plasma samples. Serum biotin was significantly lower in children than in adults, with the normal range being 4.7-22.0 ng/dL in children and 8.4-20.5 ng/dL in adults. This simple and accurate enzyme-linked immunosorbent assay method is useful for diagnosing biotin deficiency.

Predictive Factors for Efficacy and Safety of Prophylactic Theophylline for Extubation in Infants with Apnea of Prematurity.

PurposeThis study aimed to evaluate predictive factors involved in efficacy and safety in Japanese infants who received theophylline therapy to prevent apnea of prematurity (AOP) after weaning from mechanical ventilation.MethodsWe retrospectively reviewed the medical records of infants who were administered intravenous aminophylline (theophylline ethylenediamine) for AOP at the neonatal intensive care unit, Kagoshima University Hospital, Japan, between January 2009 and June 2013.ResultsA total of 100 infants were evaluated as two separate groups in terms of efficacy and safety of theophylline. Sixty-seven (67.0%) infants had effective theophylline therapy. Multivariate logistic regression analysis showed that gestational age at birth was significant, with an odds ratio of 0.59 (p < 0.001). Receiver operating characteristic analysis showed that the cut-off value was 31.1 weeks old for predicting the efficacy of theophylline (specificity, 66.7%; sensitivity, 86.6%; p < 0.001; area under the curve, 0.750; 95% confidence interval, 0.45–0.74). Adverse reactions were identified in 21 (21.0%) infants. Multivariate logistic regression analysis showed that the number of days of theophylline administration from birth was associated with an increased risk of adverse reactions after theophylline administration (p = 0.01).ConclusionsPhysicians need to be aware of the possibility that theophylline fails to produce therapeutic effects for extubation in infants aged less than 31.1 weeks old, and adverse reactions can easily develop when theophylline is administered soon after birth.

The phenotype and clinical course of Japanese Fanconi Anaemia infants is influenced by patient, but not maternal ALDH2 genotype.

Studies using Fanconi anaemia (FA) mutant mouse models suggested that the combination of a defective FA pathway and aldehyde dehydrogenase-2 (ALDH2) dysfunction could provoke bone marrow failure, leukaemia and developmental defects, and that both maternal and fetal aldehyde detoxification are crucial to protect the developing embryo from DNA damage. We studied the ALDH2 genotypes of 35 Japanese FA patients and their mothers. We found that a normal maternal ALDH2 allele was not essential for fetal development of ALDH2-deficient patients, and none of the post-natal clinical parameters were clearly affected by the maternal ALDH2 genotype in these patients.

Low serum biotin in Japanese children fed with hydrolysate formula

Given that nutritional biotin deficiency in Japanese infants has been reported, a straightforward method for estimating biotin level is needed. The biotin content in infant formula, breast milk, and the sera of infants fed with various types of formula were measured using avidin-binding assay. A commercially available ELISA kit was used for the measurement of biotin in 54 types of formula, including hydrolysate formulas for milk allergy, as well as in breast milk and in the sera of 27 infants fed with these formulas. The biotin content reached the recommended value in only five formulas. All of the hydrolysate formulas and more than half of the special formulas contained biotin <0.1 μg/dL. Serum biotin was low in infants fed only with the hydrolysate formulas, and one of them had alopecia related to biotin deficiency. While many were asymptomatic, infants fed with formulas lacking biotin are at risk of developing symptomatic disease. The addition of biotin to breast milk substitutes was finally approved in the middle of 2014, however pediatricians in Japan should still be vigilant with regard to nutritional biotin deficiency in infants for the time being.

Parental Characteristics can Explain Why Japanese Women Give Birth to the Smallest Infants in the United States.

Whether birthweight differences observed between races are due to modifiable factors remains controversial. In the United States, Asian infants weigh less than white infants and Japanese infants weigh the least. Using US Natality data, we evaluated 4132319 singleton term livebirths to parents of non-Hispanic white or Japanese race/ethnicity from 2009 to 2012. Infants were categorised by parental race/ethnicity (both white, n=4116637; Japanese father/white mother, n=2377; white father/Japanese mother, n=7478; both Japanese, n=5827). We used multivariable regression to sequentially adjust for maternal characteristics to determine to what extent they explained differences in fetal growth due to maternal race/ethnicity. Infants born to Japanese mothers were smaller by 132 (95% CI 101, 122) grams, with higher risk of small for gestational age (relative risk ratio (RRR) 1.56 (95% CI 1.47, 1.65) and lower risk of large for gestational age RRR 0.49, 95% CI 0.44, 0.54), compared to infants of white mothers. Differences in social factors and in maternal age, parity, and gestational age only minimally explained this difference. However, additionally adjusting for maternal height, body mass index and gestational weight gain substantially attenuated this difference to 20 (95% CI 12, 29) grams in birthweight, 0.91 (95% CI 0.86, 0.97) times risk of small for gestational age, and 1.06 (95% CI 0.96, 1.17) times risk of large for gestational age, with the effect similar across strata of paternal race/ethnicity. Differences in fetal growth between infants from Japanese and white mothers could be explained by differences in maternal height, pre-pregnancy weight, and gestational weight gain. Fetal growth potential appears to be similar across racial/ethnic groups when parental sizes are similar.

Increased C-reactive protein and fever in Japanese infants with food protein-induced enterocolitis syndrome.

Increased C-reactive protein (CRP) and fever are observed in some infants with food protein-induced enterocolitis syndrome (FPIES) in Japan, but the reproducibility of these findings has not yet been confirmed on oral food challenge (OFC). Fourteen infants with FPIES induced by cow's milk (CM) formula were enrolled. OFC using CM formula was performed on each infant once or repeatedly (total 18 tests), with a stepwise incremental protocol in an infection-controlled setting. CRP was measured 24 h after the last ingestion of the CM formula. Increased CRP was observed in 11 of the 18 OFC conducted (median, 2.60 mg/dL; range, 0.22-4.84 mg/dL). Fever was induced in six occasions during OFC. Serum CRP in the patients with fever increased to median 3.76 mg/dL (range, <0.7-4.84 mg/dL), which was significantly higher than that of the patients without fever (median <0.1 mg/dL; range, <0.1-2.6 mg/dL; P < 0.001). CRP during OFC significantly correlated with that at disease onset (rs = 0.62, P < 0.02). Three of the four patients with fever at disease onset also had fever during OFC. Increased CRP and fever are reproducible during OFC in some infants with FPIES, suggesting that these are not accidental phenomena, but instead are associated with FPIES itself in Japanese patients.

Complications in Infants of Diabetic Mothers Related to Glycated Albumin and Hemoglobin Levels During Pregnancy

This study was conducted to investigate whether glycated albumin is a useful glycemic marker from the point of view of infant complications for monitoring glycemic control in pregnant women with diabetes or gestational diabetes mellitus. We retrospectively studied 42 Japanese infants of diabetic mothers and their mothers at our facility between May 2010 and July 2013. The mean glycated albumin and glycated hemoglobin levels were compared between mothers of infants with complications and those without complications. We used 15.8% as the cutoff value of glycated albumin and calculated the sensitivity and specificity of items that were significantly different between the two groups. Glycated albumin was significantly higher in mothers of infants with hypoglycemia (15.5±1.8 vs. 13.8±1.2%, p=0.001), respiratory disorders (15.6±1.8 vs. 13.9±1.2%, p<0.001), hypocalcemia (15.7±2.1 vs. 14±1.2%, p=0.004), myocardial hypertrophy (15.2±1.9 vs. 13.7±1%, p=0.007), and large-for-date status (15.8±1.9 vs. 14±1.3%, p=0.002). By contrast, considering hypoglycemia, glycated hemoglobin was not significantly different between the two groups. The sensitivity and specificity with 15.8% as the cutoff value of glycated albumin were as follows: hypoglycemia (70% and 81.2%), respiratory disorders (61.5% and 82.8%), hypocalcemia (62.5% and 84.4%), myocardial hypertrophy (87.5% and 79.4%), and large-for-date status (75% and 85.3%). Glycated albumin is a useful marker of glycemic control considering infant complications during pregnancy. This study also suggests that evaluating both glycated hemoglobin and glycated albumin levels can lead to better glycemic control in pregnant women.

Age-specific percentile-based reference curve of serum procalcitonin concentrations in Japanese preterm infants.

Procalcitonin (PCT) levels are elevated early after birth in newborn infants; however, the physiological features and reference of serum PCT concentrations have not been fully studied in preterm infants. The aims of the current study were to establish an age-specific percentile-based reference curve of serum PCT concentrations in preterm infants and determine the features. The PCT concentration peaked in infants at 1 day old and decreased thereafter. At 1 day old, serum PCT concentrations in preterm infants <34 weeks’ gestational age were higher than those in late preterm infants between 34 and 36 weeks’ gestational age or term infants ≥37 weeks’ gestational age. Although the 50-percentile value in late preterm and term infants reached the adult normal level (0.1 ng/mL) at 5 days old, it did not in preterm infants. It took 9 weeks for preterm infants to reach it. Serum PCT concentrations at onset in late-onset infected preterm infants were over the 95-percentile value. We showed that the physiological feature in preterm infants was significantly different from that in late preterm infants, even in those <37 weeks’ gestational age. To detect late-onset bacterial infection and sepsis, an age-specific percentile-based reference curve may be useful in preterm infants.

International Perspectives: Clinical Kernicterus in Preterm Infants in Japan

In recent years, clinical kernicterus has been diagnosed in preterm infants on the basis of motor (kinetic) disorders such as choreoathetosis and dystonia, impairment in auditory neuropathy-type hearing, and abnormal pallidal signals on head magnetic resonance imaging. In Japan, it is currently estimated that at least 8 to 9 cases of kernicterus (approximately 2 per 1,000 cases) occur annually in preterm infants of less than 30 weeks’ gestation. Therefore, there is an urgent need to revise our jaundice management approach in preterm infants. Two major characteristics of Japanese preterm infants who develop clinical kernicterus are: (1) a peak total serum/plasma bilirubin (TB) level at 2 weeks of age or later; and (2) no markedly high total bilirubinemia. Some patients without high TB levels have high levels of unbound serum/plasma bilirubin (UB). Consequently, we propose that in Japanese preterm infants, continuous monitoring of bilirubin (using transcutaneous bilirubinometry or direct TB measurements) and/or binding status (UB levels or bilirubin-binding capacity) may be necessary.

Single nucleotide polymorphisms in AGTR1, TFAP2B, and TRAF1 are not associated with the incidence of patent ductus arteriosus in Japanese preterm infants

Persistent patent ductus arteriosus (PDA) is a frequent complication in preterm infants. Single nucleotide polymorphisms (SNP) in several genes, including angiotensin II receptor, type 1 (AGTR1), transcription factor AP-2 beta (TFAP2B) and tumor necrosis factor receptor-associated factor 1 (TRAF1), have been reported to be associated with PDA in preterm infants. The aim of this study was to evaluate the relationships between PDA in preterm infants and polymorphisms in AGTR1, TFAP2B and TRAF1 in the Japanese population. The subjects consisted of 107 preterm infants with gestational age <32 weeks. Extremely low-birthweight infants were treated with prophylactic indomethacin during the first 24 h after birth. Five SNP, namely, rs5186 in AGTR1, rs987237 and rs6930924 in TFAP2B, and rs1056567 and rs10985070 in TRAF1, were genotyped using TaqMan SNP genotyping assays. There were no significant differences in the distributions of the genotypes and allele frequencies of all studied SNP between the PDA group (n = 46) and the non-PDA group (n = 61). There were no significant associations between the studied SNP and the incidence of PDA in Japanese preterm infants. These SNP may not be clinically important predisposing factors for PDA in Japanese preterm infants.