Ryuta Yonezawa
Nihon University
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Featured researches published by Ryuta Yonezawa.
Metabolism-clinical and Experimental | 2009
Ryuta Yonezawa; Tomoo Okada; Tomomi Kitamura; Hidetoshi Fujita; Ikuhiro Inami; Masami Makimoto; Shigeharu Hosono; Michiyoshi Minato; Shigeru Takahashi; Hideo Mugishima; Tatsuo Yamamoto; Naoki Masaoka
Human fetuses have markedly low levels of serum lipids and a unique lipoprotein profile with respect to quality, with low-density lipoprotein (LDL)-like particle as the dominant cholesterol carrier. However, little is known about triglyceride (TG) distribution. In addition, lipid metabolism is important in lung development, with indications that TG from very low-density lipoprotein (VLDL) is essential for surfactant synthesis. We investigated TG distribution in preterm neonate cord blood and the relationship of VLDL-TG levels with respiratory distress syndrome (RDS). The study included 103 appropriate-for-gestational-age neonates (61 males). We performed serum lipoprotein analyses in cord blood by high-performance liquid chromatography with gel permeation columns. Term neonates had low cord blood TG concentrations distributed equally to the LDL and VLDL fractions. However, preterm neonates had even lower TG concentrations, with VLDL as the dominant carrier. The LDL-TG and high-density lipoprotein-TG concentrations in cord blood increased gradually with gestational age, but cord blood VLDL-TG concentrations increased dramatically from 32 to 34 weeks of gestational age. Neonates with RDS exhibited no RDS-specific lipoprotein profile; however, most were born before the timing of the dramatic VLDL-TG increase. Our results suggest that 34 weeks of gestation is a critical period for TG metabolism, indicating the need for evaluation of the lipid nutritional state in preterm neonates.
European Journal of Clinical Nutrition | 2010
Kayo Yoshikawa; Tomoo Okada; Shun Munakata; Aya Okahashi; Ryuta Yonezawa; Masami Makimoto; Shigeharu Hosono; Shori Takahashi; Hideo Mugishima; Tatsuo Yamamoto
Background/Objectives:Subcutaneous adipose tissue grows rapidly during the first months of life. Lipoprotein lipase (LPL) has a quantitatively important function in adipose tissue fat accumulation and insulin-like growth factor-I (IGF-I) is a determinant of neonatal growth. Recent studies showed that LPL mass in non-heparinized serum (LPLm) was an index of LPL-mediated lipolysis of plasma triacylglycerol (TG). The objective was to know the influence of serum LPL and IGF-I on neonatal subcutaneous fat growth, especially on catch-up growth in low birth weight infants.Subjects/Methods:We included 47 healthy neonates (30 males, 17 females), including 7 small for gestational age. We measured serum LPLm and IGF-I concentrations at birth and 1 month, and analyzed those associations with subcutaneous fat accumulation.Results:Serum LPLm and IGF-I concentrations increased markedly during the first month, and positively correlated with the sum of skinfold thicknesses both at birth (r=0.573, P=0.0001; r=0.457, P=0.0035) and at 1 month (r=0.614, P<0.0001; r=0.787, P<0.0001, respectively). In addition, serum LPLm concentrations correlated inversely to very low-density lipoprotein (VLDL)-TG levels (r=−0.692, P<0.0001 at birth; r=−0.429, P=0.0052 at 1 month). Moreover, the birth weight Z-score had an inverse association with the postnatal changes in individual serum LPLm concentrations (r=−0.639, P<0.0001).Conclusions:Both serum LPLm and IGF-I concentrations were the determinants of subcutaneous fat accumulation during the fetal and neonatal periods. During this time, LPL-mediated lipolysis of VLDL-TG may be one of the major mechanisms of rapid growth in subcutaneous fat tissue. Moreover, LPL, as well as IGF-I, may contribute to catch-up growth in smaller neonates.
Clinica Chimica Acta | 2012
Nobuhiko Nagano; Tomoo Okada; Ryuta Yonezawa; Kayo Yoshikawa; Hidetoshi Fujita; Yukihiro Usukura; Masami Makimoto; Sigeharu Hosono; Yukihiko Fujita; Shigeru Takahashi; Hideo Mugishima; Tatsuo Yamamoto
BACKGROUND Late preterm infants (LPIs; 34-37 gestational weeks at birth) have higher risk for several morbidities than do term infants (TIs). It has been suggested that a cholesterol and fatty acid supply may improve their outcomes. We investigated the lipoprotein subclass profile in LPIs to evaluate their early postnatal lipid metabolism. METHODS Eighty-one infants (25 LPIs, 56 TIs) were included. Cholesterol and triglyceride (TG) concentrations in 12 lipoprotein subclasses were measured at birth and at 1 month using HPLC. RESULTS In LPIs, the cord blood exhibited higher cholesterol concentrations in medium and large subclasses of very low-density lipoprotein (VLDL), low-density lipoprotein (LDL) and high-density lipoprotein (HDL) compared to the values in TIs. During the first month of life, LPIs had greater increases in cholesterol concentrations of medium and large subclasses of VLDL than TIs, whereas postnatal increases in cholesterol concentrations of medium and large subclasses of LDL and HDL were smaller. TG concentrations were not different in each VLDL subclass at birth and at 1 month. CONCLUSIONS In LPIs, cord blood lipoprotein subclass profiles and the early postnatal change exhibited different, especially in cholesterol concentrations.
Thrombosis Research | 2012
Hiroshi Yagasaki; Maiko Kato; Katsuyoshi Shimozawa; Maiko Hirai; Eri Nishikawa; Hirotsugu Okuma; Wakako Ishii; Yuki Imai; Masaharu Matsumura; Ryuta Yonezawa; Kayo Yoshikawa; Hiroyuki Shichino; Motoaki Chin; Hideo Mugishima
INTRODUCTION Recombinant thrombomodulin (rTM), which degrades factors Va and VIIIa by activating protein C, has been developed as a new drug for treating disseminated intravascular coagulation (DIC). MATERIALS AND METHODS Since July 2009, we have treated 25 children with DIC using rTM (380 U/kg/day, or 130 U/kg/day for newborns) as a first-line therapy. Median duration of rTM administration was 5 consecutive days (range, 2-13 days). We employed DIC criteria of the Japan Welfare and Health Ministry. The first day on which rTM treatment was given was defined as day 1. RESULTS Median patients age was 3 years. Underlying diseases were hematological disorders (n=13) and severe infection (n=12). Overall, 20 of the 25 patients had recovered from DIC by day 7 and 22 of the 25 patients remained alive at day 28. Median Pediatric Logistic Organ Dysfunction score improved from 11 on day 1 to 2 on day 7 (p=0.009). Laboratory data (median) on day 7 (prothrombin time (PT) ratio, 1.15; fibrin and fibrinogen degradation products (FDP), 9.6 mg/l; D-dimer, 1.6 mg/l FEU; antithrombin, 112%; protein C, 105%) were significantly improved compared to results on day 1 (PT ratio, 1.39; FDP, 21.6 mg/l; D-dimer, 6.4 mg/l FEU; antithrombin, 86%; protein C, 54%). Whereas, 5 patients failed to respond and serious bleeding events were observed in 2 newborns. CONCLUSION The efficacy of rTM cannot be assessed from the present dataset, due to several limitations such as the small heterogenous patient cohort, and the lack of age- and disease-matched controls. Nevertheless, this case-series remains important in terms of enabling further prospective control studies to evaluate the efficacy of rTM in children.
Journal of Atherosclerosis and Thrombosis | 2016
Emiko Saito; Tomoo Okada; Yuriko Abe; Minako Kazama; Ryuta Yonezawa; Yuki Kuromori; Fujihiko Iwata; Mitsuhiko Hara
AIM To investigate the relationship between the clustering of metabolic syndrome (MetS) components and non-high-density lipoprotein cholesterol (non-HDL-C) levels in Japanese obese boys. METHODS Subjects were 58 obese boys aged 12.0±2.6 years, which were categorized into three subgroups: abdominal obesity, pre-MetS (abdominal obesity+1 component), and MetS (abdominal obesity+2 or more components). RESULTS Sixteen (27.6%) and 32 (55.2%) of the obese boys were diagnosed as pre-MetS and MetS, respectively. The mean non-HDL-C level in total subjects was 139.0±36.4 mg/dl and that in boys with abdominal obesity, pre-MetS, and MetS were 112.9±34.4, 135.4±37.9, and 149.0±32.6 mg/dl, respectively (p=0.0183, ANOVA). CONCLUSIONS Japanese obese boys with MetS exhibited elevated non-HDL-C levels, suggesting that they may have a higher risk for the development of atherosclerotic diseases.
Case reports in pediatrics | 2015
Ryuta Yonezawa; Tsukasa Kuwana; Kengo Kawamura; Yasuji Inamo
Pediatric invasive community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infection is very serious and occasionally fatal. This infectious disease is still a relatively rare and unfamiliar infectious disease in Japan. We report a positive outcome in a 23-month-old Japanese girl with meningitis, osteomyelitis, fasciitis, necrotizing pneumonia, urinary tract infection, and bacteremia due to CA-MRSA treated with linezolid. PCR testing of the CA-MRSA strain was positive for PVL and staphylococcal enterotoxin b and negative for ACME. SCC mec was type IVa. This case underscores the selection of effective combinations of antimicrobial agents for its treatment. We need to be aware of invasive CA-MRSA infection, which rapidly progresses with a serious clinical course, because the incidence of the disease may be increasing in Japan.
Pediatric Emergency Care | 2017
Kasuga Y; Tatsuo Fuchigami; Fukuda A; Shori Takahashi; Murai T; Ryuta Yonezawa; Miyashita M; Ryutaro Kohira; Yukihiko Fujita
Acute focal bacterial nephritis (AFBN) is a localized bacterial infection of the kidney presenting as an inflammatory mass without frank abscess formation. In children, most patients with AFBN present with nonspecific conditions, such as fever, vomiting, and abdominal pain. A small number of reported cases are accompanied by neurological symptoms, including meningeal irritation, unconsciousness, and seizures. We experienced 2 rare cases of AFBN associated with central nervous system lesions. The first case was a 3-year-old girl who had neurological symptoms, including unconsciousness and seizures, with AFBN associated with acute reversible encephalopathy. The second case was a 5-year-old girl who had neurological symptoms, including unconsciousness, with AFBN accompanied by clinically mild encephalitis/encephalopathy with a reversible splenial lesion.
Journal of Childhood Obesity | 2016
Yuriko Abe; Tomoo Okada; Hiromi Okuma; Minako Kazama; Ryuta Yonezawa; Emiko Saito; Yuki Kuromori; Fujihiko Iwata; Mitsuhiko Hara; Tatsuo Fuchigami; Shori Takahashi
Background: Alterations in the very low-density lipoprotein (VLDL) subclass profile have been demonstrated in obese and insulin resistant adults; however, little information on VLDL subclasses is available in children. We determined the association between abdominal adiposity, insulin resistance, and triglyceride (TG) levels in each VLDL subclass in Japanese school children. Methods: One hundred sixty-four children (79 boys and 85 girls), 10.9 ± 1.6 years of age (mean ± SD), were recruited. We obtained the waist-to-height ratio (WHtR), lipid profile, and HOMA-R data from all children. The VLDL subclass profile was analyzed by HPLC. Results: Children of either gender with abdominal obesity (WHtR ≥ 0.5) had higher concentrations of large, medium, and small VLDL-TG in conjunction with the shift to larger size and elevated HOMA-R. The WHtR was positively related to concentrations of large (boys: r = 0.5800, p < 0.0001; girls: r = 0.3841, p = 0.0003) and medium (r = 0.5265, p < 0.0001; r = 0.3320, p = 0.0019) VLDL-TG. The small VLDL-TG concentration was positively correlated to the WHtR in boys (r = 0.4902, p < 0.0001), but not girls. In multiple regression analyses, the WHtR was an independent determinant of large, medium, and small VLDL-TG concentrations in boys, but not in girls, taking HOMA-R into account. Conclusions: Abdominal obesity was associated with the VLDL subclass profile in Japanese school children; however, the impact of abdominal adiposity on the VLDL subclass alteration demonstrated a gender difference.
Obesity Research & Clinical Practice | 2013
Yayoi Yoshino; Tomoo Okada; Yuriko Abe; Minako Odaka; Yuki Kuromori; Ryuta Yonezawa; Fujihiko Iwata; Hideo Mugishima
AIM In a mice study, insulin suppressed apolipoprotein A-V (apoA-V) gene expression in a dose dependent manner. Thus, we investigated the association between apoA-V levels and dyslipidemias in obese children with hyperinsulinemia. METHODS The subjects were 17 obese children (15 male, 2 female) aged 11.8 ± 2.4 years. Total cholesterol (TC), high-density lipoprotein cholesterol (HDLC), triglyceride (TG), apoA-V and insulin levels were determined. RESULTS Obese children with hyperinsulinemia had greater percent overweight, higher TG level, lower HDLC level and lower apoA-V level than those without hyperinsulinemia. In simple regression analysis, apoA-V level correlated negatively with TG (r = -0.613, p = 0.0152) and insulin levels (r = -0.566, p = 0.0279), and positively correlated with HDLC (r = 0.811, p = 0.0002). In stepwise regression analysis, insulin level emerged as the independent determinant of TG level after apoA-V level was taken into account, whereas apoA-V emerged as the independent determinant of HDLC level after adjusting for insulin level. CONCLUSIONS Insulin may be a potent regulator of serum apoA-V level in obesity, and apoA-V level may partly contribute to the development of obesity-associated dyslipidemia.
Early Human Development | 2011
Tomoo Okada; Ryuta Yonezawa; Michio Miyashita; Hideo Mugishima