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Dive into the research topics where Akio Nakai is active.

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Featured researches published by Akio Nakai.


The Journal of Allergy and Clinical Immunology | 1992

Urinary leukotriene E4 after exercise challenge in children with asthma

Yoshiharu Kikawa; Takeshi Miyanomae; Yasuhiro Inoue; Masakazu Saito; Akio Nakai; Yousuke Shigematsu; Susumu Hosoi; Masakatsu Sudo

To assess the role of sulfidopeptide leukotrienes in the pathogenesis of exercise-induced asthma (EIA), the urinary levels of leukotriene E4 (LTE4), a metabolite of LTC4 and LTD4, were measured by RIA before and after exercise in 13 children with EIA and 10 healthy children. Mass spectrometry was used to confirm the presence of LTE4 in urine and the specificity of the RIA. There was no significant difference in the urinary LTE4 levels before exercise between the children with asthma and healthy children (109 [21 to 265] versus 122 [45 to 156] pg/mg of creatinine; median and range). Urinary LTE4 levels increased significantly after exercise in the children with EIA (from 109 [21 to 265] to 196 [40 to 655] pg/mg of creatinine; median and range; p less than 0.05) but not in the healthy children. The children with asthma demonstrated no significant correlation between the LTE4 level after exercise and the degree of bronchoconstriction, as revealed by the maximal percent fall in the peak expiratory flow rate. Taken together with a recent study that pretreatment with a potent and selective LTD4 antagonist markedly attenuated EIA, our findings suggest that sulfidopeptide leukotrienes may play some role in the pathogenesis of this type of asthma with other factors also being involved in determining the overall airway response.


Journal of Computer Assisted Tomography | 2002

Transient MR signal changes in the splenium of the corpus callosum in rotavirus encephalopathy: value of diffusion-weighted imaging.

Ritsuyo Kobata; Hirokazu Tsukahara; Akio Nakai; Akihiko Tanizawa; Yoshiyuki Ishimori; Yasutaka Kawamura; Hiroshi Ushijima; Mitsufumi Mayumi

The authors report serial brain MR findings from a 2-year-old girl with rotavirus encephalopathy. The lesion in the splenium of the corpus callosum showed restricted proton diffusion, suggesting local cytotoxic edema. Diffusion-weighted images demonstrated the lesion more conspicuously than other techniques, such as fluid-attenuated inversion-recovery and T1- and T2-weighted images. The findings were reversible on follow-up MRI obtained 4 days later. Diffusion-weighted MRI is a potentially useful method for detecting early changes of rotavirus encephalopathy, although the mechanism of the restricted diffusion is not clearly identified.


Pediatric Research | 1996

Prenatal diagnosis of organic acidemias based on amniotic fluid levels of acylcarnitines

Yosuke Shigematsu; Ikue Hata; Akio Nakai; Yoshiharu Kikawa; Masakatsu Sudo; Yukie Tanaka; Seiji Yamaguchi; Cornelis Jakobs

Acylcarnitines in amniotic fluid samples were analyzed for the prenatal diagnosis of propionic acidemia, methylmalonic aciduria, isovaleric acidemia, and glutaric aciduria by electrospray tandem mass spectrometry. Although the levels of the specific acylcarnitine between affected and unaffected cases showed an overlap, the ratios of propionylcarnitine to 4-carbon acylcarnitine levels for propionic acidemia and methylmalonic aciduria, those of isovalerylcarnitine to propionylcarnitine for isovaleric acidemia, and those of glutarylcarnitine to propionylcarnitine for glutaric aciduria type I were shown to be reliable indicators in the prenatal diagnosis. In addition, it is suggested that the combination of the ratios of glutarylcarnitine, isovalerylcarnitine, and hexanoylcarnitine to propionylcarnitine may be useful for the prenatal diagnosis of glutaric aciduria type II.


American Journal of Human Genetics | 1997

Identification of genetic mutations in Japanese patients with fructose-1,6-bisphosphatase deficiency

Yoshiharu Kikawa; Manabu Inuzuka; Byun Young Jin; Satomi Kaji; Jun-ichi Koga; Yoshiki Yamamoto; Kazuro Fujisawa; Ikue Hata; Akio Nakai; Yosuke Shigematsu; Hideo Mizunuma; Akira Taketo; Mitsufumi Mayumi; Masakatsu Sudo

Fructose-1,6-bisphosphatase (FBPase) deficiency is an autosomal recessive inherited disorder and may cause sudden unexpected infant death. We reported the first case of molecular diagnosis of FBPase deficiency, using cultured monocytes as a source for FBPase mRNA. In the present study, we confirmed the presence of the same genetic mutation in this patient by amplifying genomic DNA. Molecular analysis was also performed to diagnose another 12 Japanese patients with FBPase deficiency. Four mutations responsible for FBPase deficiency were identified in 10 patients from 8 unrelated families among a total of 13 patients from 11 unrelated families; no mutation was found in the remaining 3 patients from 3 unrelated families. The identified mutations included the mutation reported earlier, with an insertion of one G residue at base 961 in exon 7 (960/961insG) (10 alleles, including 2 alleles in the Japanese family from our previous report [46% of the 22 mutant alleles]), and three novel mutations--a G-->A transition at base 490 in exon 4 (G164S) (3 alleles [14%]), a C-->A transversion at base 530 in exon 4 (A177D) (1 allele [4%]), and a G-->T transversion at base 88 in exon 1 (E30X) (2 alleles [9%]). FBPase proteins with G164S or A177D mutations were enzymatically inactive when purified from E. coli. Another new mutation, a T-->C transition at base 974 in exon 7 (V325A), was found in the same allele with the G164S mutation in one family (one allele) but was not responsible for FBPase deficiency. Our results indicate that the insertion of one G residue at base 961 was associated with a preferential disease-causing alternation in 13 Japanese patients. Our results also indicate accurate carrier detection in eight families (73%) of 11 Japanese patients with FBPase deficiency, in whom mutations in both alleles were identified.


Pediatric Research | 1991

Exercise-induced urinary excretion of leukotriene E4 in children with atopic asthma

Yoshiharu Kikawa; Susumu Hosoi; Yasuhiro Inoue; Masakazu Saito; Akio Nakai; Yousuke Shigematsu; Takao Hirao; Masakatsu Sudo

ABSTRACT: Urinary levels of leukotriene (LT) E4, a stable end-product of LTC4 and LTD4, were measured before and after exercise in 10 children with severe asthma and seven children with moderate asthma using HPLC and RIA to clarify the relationship of LT to the severity of asthma and to the degree of bronchospasm in exercise-induced asthma. The urinary LTE4 level significantly increased after exercise in the severe asthma group, but not in the moderate asthma group (14.3 ± 14.5 to 24.3 ± 20.6 versus 19.6 ± 12.3 to 17.6 ± 10.8 ng/mmol creatinine, p < 0.05). The urinary LTE4 level increased in 10 patients (eight with severe asthma), and it decreased in seven patients (five with moderate asthma). A significant difference in the degree of bronchospasm after exercise (as shown by the maximal % fall in the peak expiratory flow rate), was seen when patients with increased urinary LTE4 excretion were compared with those with decreased excretion (60.4 ± 17.3 versus 24.1 ± 14.3%, p < 0.01). Our findings suggest that exercise-induced asthma, or at least a subtype of exercise-induced asthma, may partly develop through the release of LTC4.


Research in Developmental Disabilities | 2011

Evaluation of the Japanese version of the Developmental Coordination Disorder Questionnaire as a screening tool for clumsiness of Japanese children.

Akio Nakai; Taishi Miyachi; Ryo Okada; Iori Tani; Shunji Nakajima; Masafumi Onishi; Chikako Fujita; Masatsugu Tsujii

Developmental Coordination Disorder (DCD) is characterized by clumsiness and coordination difficulties. DCD interferes with academic performance and participation in physical activities and psychosocial functions, such as self-esteem, cognition, or emotion, from childhood through adolescence to adulthood. DCD is a common pediatric condition and its prevalence is estimated to be 6% worldwide. Although English questionnaires are available, there is no questionnaire to identify DCD in Japan, and therefore, no information on its prevalence is available. Recently, we developed the Japanese version of the Developmental Coordination Disorder Questionnaire (DCDQ-J). The purpose of this study was to describe the applicability of the DCDQ-J for use with a community-based population of children in Japan and to investigate the relationships between coordination and attention-deficit hyperactivity disorder (ADHD) tendencies or intelligence. The DCDQ-J was completed by 6330 parents or guardians of children and adolescents. We employed the ADHD-rating scale and determined the intelligence quotient (IQ) of the children. Two-way analysis of variance showed that the scores linearly increased as the childrens grades advanced in 2 subscales, namely, control during movement and fine motor. In contrast, non-linear changes were found in the scores of the general coordination subscale. The total scores of the DCDQ-J and ADHD-RS were significantly correlated, but no relationship between DCDQ-J scores and IQ was found. The DCDQ-J is expected to be a useful screening tool to identify and assess motor coordination difficulties of children in Japan and enable cross-cultural comparisons.


Archives of General Psychiatry | 2011

Brain Regional α-[11C]Methyl-L-Tryptophan Trapping in Medication-Free Patients With Obsessive-Compulsive Disorder

Alexandre Berney; Marco Leyton; Paul Gravel; Igor Sibon; Debbie Sookman; Pedro Rosa Neto; Mirko Diksic; Akio Nakai; Gilbert Pinard; Christo Todorov; Hidehiko Okazawa; Pierre Blier; Thomas E. Nordahl; Chawki Benkelfat

CONTEXT The hypothesis of a serotonin (5-hydroxytryptamine [5-HT]) dysfunction in obsessive-compulsive disorder (OCD) stems largely from the clinical efficacy of 5-HT reuptake inhibitors. Serotonergic abnormalities in the unmedicated symptomatic state, however, remain to be fully characterized. OBJECTIVE To investigate brain regional 5-HT synthesis, as indexed by positron emission tomography and the α-[(11)C]methyl-L-tryptophan trapping constant (K*), in treatment-free adults meeting criteria for OCD. DESIGN Between-group comparison. SETTING Department of Psychiatry and Montreal Neurological Institute, McGill University, and Department of Psychology, McGill University Health Centre, Quebec, Canada. PARTICIPANTS Twenty-one medication-free patients with OCD (15 men with a mean [SD] age of 33.2 [9.3] years and 6 women with a mean [SD] age of 35.8 [7.1] years) and 21 healthy controls matched for age and sex (15 men with a mean [SD] age of 32.9 [10.1] years and 6 women with a mean [SD] age of 36.5.5 [8.6] years). Main Outcome Measure The α-[(11)C]methyl-L-tryptophan brain trapping constant K*, which was analyzed with Statistical Parametric Mapping (SPM8) and with proportional normalization (extent threshold of 100 voxels with a peak threshold of P ≤ .005). RESULTS Compared with healthy controls, the patients with OCD exhibited significantly greater α-[(11)C]methyl-L-tryptophan trapping in the right hippocampus and left temporal gyrus (Brodmann area 20). In the larger subsample of all men, these same differences were also evident, as well as higher K* values in the caudate nucleus. Individual differences in symptom severity correlated positively with K* values sampled from the caudate and temporal lobe of the patients with OCD, respectively. There were no regions where the patients exhibited abnormally low K* values. Volumetric analyses found no morphometric alterations that would account for the group differences. CONCLUSION The results support previous reports of greater striatal and temporal lobe activity in patients with OCD than in healthy controls and suggest that these disturbances include a serotonergic component. Previously reported glucose metabolic disturbances in OCD involving the orbitofrontal and cingulate cortices, in comparison, might reflect postsynaptic changes in the serotonergic system.


Pediatric Neurology | 1995

MRI findings of Zellweger syndrome

Akio Nakai; Yosuke Shigematsu; Koichi Nishida; Yoshiharu Kikawa; Yukuo Konishi

A patient with Zellweger syndrome, who manifested marked dilatation of the lateral ventricles, observed at 34 weeks gestation by fetal ultrasonography, is reported. Postnatal magnetic resonance imaging revealed marked colpocephaly and hypogenesis of the posterior part of the corpus callosum. However, pachygyria was limited to the perisylvian regions. Biochemical diagnosis was based on increased serum very-long-chain fatty acids, 2-hydroxysebacic aciduria, and the detection of the ghosts of peroxisomal membrane in cultured fibroblasts. The patient was classified as belonging to group B of this syndrome by complementation study.


PLOS ONE | 2016

Impacts of Perinatal Dioxin Exposure on Motor Coordination and Higher Cognitive Development in Vietnamese Preschool Children: A Five-Year Follow-Up

Nghi Ngoc Tran; Kyoko Ozawa; Muneko Nishijo; Anh Thi Nguyet Nguyen; Tuong Quy Tran; Luong Van Hoang; Anh Hai Tran; Vu Huy Anh Phan; Akio Nakai; Yoshikazu Nishino; Hisao Nishijo

Dioxin concentrations remain elevated in the environment and in humans residing near former US Air Force bases in South Vietnam. Our previous epidemiological studies showed adverse effects of dioxin exposure on neurodevelopment for the first 3 years of life. Subsequently, we extended the follow-up period and investigated the influence of perinatal dioxin exposure on neurodevelopment, including motor coordination and higher cognitive ability, in preschool children. Presently, we investigated 176 children in a hot spot of dioxin contamination who were followed up from birth until 5 years old. Perinatal dioxin exposure levels were estimated by measuring dioxin levels in maternal breast milk. Dioxin toxicity was evaluated using two indices; toxic equivalent (TEQ)-polychlorinated dibenzo-p-dioxins/furans (PCDDs/Fs) and concentration of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Coordinated movements, including manual dexterity, aiming and catching, and balance, were assessed using the Movement Assessment Battery for Children, Second Edition (Movement ABC-2). Cognitive ability was assessed using the nonverbal index (NVI) of the Kaufman Assessment Battery for Children, Second Edition (KABC-II). In boys, total test and balance scores of Movement ABC-2 were significantly lower in the high TEQ- PCDDs/Fs group compared with the moderate and low exposure groups. NVI scores and the pattern reasoning subscale of the KABC-II indicating planning ability were also significantly lower in the high TCDD exposure group compared with the low exposure group of boys. However, in girls, no significant differences in Movement ABC-2 and KABC-II scores were found among the different TEQ-PCDDs/Fs and TCDD exposure groups. Furthermore, in high risk cases, five boys and one girl highly exposed to TEQ-PCDDs/Fs and TCDD had double the risk for difficulties in both neurodevelopmental skills. These results suggest differential impacts of TEQ-PCDDs/Fs and TCDD exposure on motor coordination and higher cognitive ability, respectively. Moreover, high TEQ-PCDDs/Fs exposure combined with high TCDD exposure may increase autistic traits combined with developmental coordination disorder.


Pediatrics International | 2010

Detection of cytomegalovirus in preserved umbilical cord from a boy with autistic disorder

Masao Kawatani; Akio Nakai; Takashi Okuno; Ritsuyo Kobata; Masako Moriuchi; Hiroyuki Moriuchi; Hirokazu Tsukahara; Mitsufumi Mayumi

an adverse outcome in neonates with a large fetomaternal hemorrhage. Diagnosis of anemia and other laboratory data serve as a reference, but it is still difficult to evaluate the prognosis for an individual child. Poor outcomes are likelier when there is a long period of artificial respiration, when initial lactation is late or when abnormal waves on EEG continues, but a poor outcome is not certain. When ischemic changes detected by a head MRI are extensive, the child is expected to experience developmental delays. A head MRI is currently considered the most useful tool to predict outcomes. Massive FMH is a known antecedant to fetal manifestations, such as decreased movements, sinusoidal heart rhythms, nonhemolytic neonatal anemia, and non-immune hydrops fetalis. These symptoms are usually late manifestations observed in a fetus that has been bleeding into the maternal circulation for a considerable period of time. FMH causes ischemic brain injury and is associated with an adverse neurological outcome. The prognosis may be improved by prompt delivery and a neonatal transfusion, or if the fetus is premature, intrauterine transfusion can be performed. Appropriate analysis of highly suspicious clinical results can lead to correct diagnosis of this condition.

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Mitsufumi Mayumi

Boston Children's Hospital

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Shogo Hirata

Ibaraki Christian University

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