Akifumi Tokita

Juntendo University, Edo, Tōkyō, Japan

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Publications (50)337.13 Total impact

  • Source
    Cell 03/2012; 149(1):245. · 31.96 Impact Factor
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    ABSTRACT: Ribavirin-related anemia is a serious side-effect of the pegylated interferon and ribavirin therapy used for hepatitis C, and may be cause for a reduction in ribavirin dose or even cessation of treatment. The aim of this study was to evaluate the prophylactic effects of oral eicosapentaenoic acid (EPA) supplementation on ribavirin-induced hemolytic anemia in pediatric and young adult patients. Twelve chronic hepatitis C patients ranging in age from 3 to 21 years (mean, 13.9 ± 5.1 years) who received pegylated interferon α-2b and ribavirin combination therapy were randomized to either the control group (n = 6) or EPA group (n = 6). Blood samples were collected before, and at 4, 8, and 16 weeks after treatment to measure clinical laboratory parameters. The reduction in hemoglobin levels of the EPA group was significantly ameliorated at 8 and 16 weeks when compared to the control group (P < 0.05). There was no significant difference in plasma ribavirin concentrations between the two groups during the treatment. However, one patient in the control group had a reduction in ribavirin dose. EPA supplementation prevented ribavirin-induced hemolytic anemia during combination therapy with pegylated interferon α-2b and ribavirin in pediatric and young adult patients.
    Pediatrics International 02/2012; 54(4):528-31. · 0.88 Impact Factor
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    ABSTRACT: Vitamin D insufficiency and deficiency are common in the elderly. Most previous studies using alendronate have used vitamin D supplementation regardless of individual vitamin D status. However, the minimum required vitamin D levels for the efficacy of alendronate treatment of osteoporosis remain unclear. Fifty-two postmenopausal women, diagnosed with osteoporosis, were enrolled in this prospective study, in which they took 5 mg of alendronate daily for 6 months without any supplements. Associations between baseline factors and their changes during the treatment and the change in the lumbar spine bone mineral density (LS-BMD) were examined. The most appropriate cut-off level of 25-hydroxyvitamin D (25[OH]D) for the optimal increase in LS-BMD with alendronate was determined using the Akaike information criterion statistical criterion. Overall, alendronate treatment significantly increased LS-BMD by 4.7%. The basal serum 25(OH)D and change in urinary NTX were significantly associated with the increase in LS-BMD. The increase in LS-BMD between the two groups was not different when comparing those with baseline 25(OH)D above vs. below 30 ng/ml. However, 25(OH)D of 25 ng/ml was determined to be the minimum required vitamin D level for an adequate effect of alendronate. Vitamin D status may affect the increase in LS-BMD with alendronate treatment in individuals being treated for osteoporosis, and a 25(OH)D level >25 ng/ml appears to be required for an optimal LS-BMD response.
    Calcified Tissue International 10/2009; 85(5):398-404. · 2.75 Impact Factor
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    ABSTRACT: Acetabular dysplasia (AD) contributes to the development of osteoarthritis of the hip. A rotational acetabular osteotomy (RAO) is one of the methods of pelvic osteotomy to prevent or treat secondary osteoarthritis of the hip. Although most of the patients that undergo RAO show satisfactory results, some have poor results. This study investigated whether gene polymorphisms of both the vitamin D receptor (VDR) and oestrogen receptor (ER) are involved in both AD and the postoperative results following RAOs. Sixty-four Japanese patients with AD who were treated by an RAO were enrolled in this study (59 women and 5 men, aged 13-59, with an average age of 40.3). Gene polymorphisms of the VDR [ApaI and TaqI restriction fragment length polymorphisms (RFLPs)] and ER (PvuII and XbaI RFLPs) were determined in these patients. The relationship between both the AD and radiographic postoperative changes of the hip joint after an RAO with these gene polymorphisms were examined. The frequencies of ER gene polymorphism coded as pp (RFLP/PvuII) in patients with AD were statistically significantly different (p = .011) from those coded as both PP and Pp. The joint space width narrowed even after RAO in 90% of the patients with the pp gene polymorphism, while it narrowed in only 35% of the patients with either PP or Pp seven years or longer after an RAO. The PvuII polymorphism in the ER gene was associated with the postoperative result of an RAO, while no association was observed between the AD with VDR and ER gene polymorphisms.
    International Orthopaedics 03/2009; 33(4):1155-64. · 2.32 Impact Factor
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    ABSTRACT: The correlation between reduced bone mineral density (BMD) and the disease anorexia nervosa (AN) has long been established. The aim of the present study was to examine the relationship in more detail, particularly focusing on the increasing incidence of the disease occurring in adolescent patients. Twenty-four girls diagnosed with AN were enrolled in the study. All subjects ranged in age from 11.1 to 15.5 years, with an average age of 13.5 years. The BMD of lumbar spines and femoral necks were measured. All the values for BMD at admission were expressed as means +/- SD and patients with and without menarche were separately investigated. The average BMD of lumbar spines at the time of admission was -0.51 SD in total. However, the average BMD of patients without menarche was -1.28 SD, which was significantly lower than the -0.16 SD on average in patients with menarche. As a whole the BMD of femoral necks at admission tended to be lower than that of lumbar spines. Similarly, it was lower in patients without menarche (-1.7 SD on average) than in those with menarche (-0.77 SD on average). BMD was lower in children and adolescent AN patients without menarche, and such a tendency was more significant at the femoral neck region. In child AN cases without menarche, the BMD, especially at the femoral neck, needs to be measured, and later recovery should be monitored closely over a long period.
    Pediatrics International 11/2007; 49(5):637-40. · 0.88 Impact Factor
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    ABSTRACT: There have been few studies of the thyroid stimulating hormone (TSH) surge in extremely low-birthweight (ELBW) infants, and the relationship between thyroid hormones and respiratory distress syndrome (RDS) has yet to be clarified. The present study sought to determine the serum levels of free T4 (fT4) and TSH in ELBW infants and to examine the relationship between these levels and the development of RDS. The authors measured serum fT4 and TSH levels soon after birth in 449 preterm infants, who were born at 22-36 weeks of gestation, and determined the associations between these levels, the incidence of RDS, and the recognized clinical factors associated with RDS. Serum fT4 and TSH levels, and the fT4/TSH ratio, in the group at 22-24 weeks of gestation were significantly lower than those in the group at 28-36 weeks. The levels and ratio increased significantly with increasing gestational age. There were significant correlations between the serum fT4 level and the birthweight, Apgar score, and gender, and between the serum TSH level and the gestational age, mode of delivery, and birthweight. No significant relationship between the incidence of RDS and the serum levels of fT4 and TSH was observed. The authors' results suggest that the serum levels of fT4 and TSH in ELBW infants are very low, and that these levels are not correlated with the occurrence of RDS.
    Pediatrics International 09/2007; 49(4):447-51. · 0.88 Impact Factor
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    ABSTRACT: TBP-free TAF II-containing-type HAT complex subclasses, which contain hGCN5 HAT and TRRAP, appear to act as common coactivator complexes for nuclear receptors. However, their physiological significance with respect to each nuclear receptor remains to be established. To address this issue, we used hepatic cell lines (HepG2) with reduced endogenous TRRAP expression through antisense RNA expression or with overexpressed TRRAP or other major coactivators. The ligand-induced transactivation function of liver X receptor alpha (LXRalpha) and farnesoid X receptor/bile acid receptor reflected TRRAP expression levels, while that of PPARgamma did not. A GST pull-down assay indicated that TRRAP contains two potential LXRalpha-interacting domains in the C-terminal and central domains. Expression of antisense TRRAP RNA in HepG2 cells abolished the ligand-induced expression of LXRalpha target genes. These results suggested that TRRAP plays an important role as a coactivator, presumably part of a complex, in lipid metabolism through regulation of the LXRalpha-mediated gene cascade in hepatic cells.
    Biochemical and Biophysical Research Communications 03/2005; 327(3):933-8. · 2.28 Impact Factor
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    ABSTRACT: This study examined whether or not a decrease in bone mineral density (BMD) induced by the use of gonadotropin-releasing hormone agonist (GnRHa) during sexual maturation is affected by vitamin D receptor and/or estrogen receptor gene polymorphisms, like the phenomenon observed during the postmenopausal period. In 43 patients who received GnRHa therapy for 6 months to treat uterine myoma or endometriosis at our department and who were confirmed to have pituitary down-regulation, we measured bone density before and after GnRHa treatment using DXA and analyzed the bone metabolism turnover using bone metabolic markers. Polymorphisms were analyzed by RFLP using FokI and TaqI for the vitamin D receptor gene and PvuII and XbaI for the estrogen receptor gene. The then determined gene polymorphism was analyzed in relation to the percentage decreases in BMD following GnRHa treatment. The patients were divided by f, t into two groups: (f, t) < 2 (Group V-I) and (f, t) > or = 2 (Group V-II). They were also divided by P, x into two groups (P, x) < 3 (Group E-I) and (P, x) > or = 3 (Group E-II). The BMD change was significantly higher in Group V-II than in Group V-I. Group E-II tended to have a higher BMD change than Group E-I, although this difference was not statistically significant. Patients who often have f and t polymorphism are more likely to show BMD reduction following GnRHa therapy, like the phenomenon seen during the postmenopausal period, than patients with other gene polymorphisms. Measures to avoid BMD reduction are required when using GnRHa in such patients.
    Journal of Obstetrics and Gynaecology Research 05/2004; 30(2):130-5. · 0.84 Impact Factor
  • Akifumi Tokita, Ken Hisata, Kyoko Nishizawa
    Nippon rinsho. Japanese journal of clinical medicine 03/2004; 62 Suppl 2:155-9.
  • Nippon rinsho. Japanese journal of clinical medicine 03/2004; 62 Suppl 2:186-9.
  • Journal of Pediatric Gastroenterology and Nutrition - J PEDIAT GASTROENTEROL NUTR. 01/2004; 39.
  • Ken Hisada, Kyoko Nishizawa, Akifumi Tokita
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    ABSTRACT: The fundamental role of vitamin D receptor (VDR) gene polymorphisms have been reviewed. The VDR gene polymorphisms are associated with the intestinal calcium absorption , rate of bone gain and loss. The observed variability in younger and elderly people in the response of bone mass to calcium intake and supplementation may be explained partly by the interaction between environmental and genetic factors.
    Clinical calcium 08/2003; 13(7):869-74.
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    ABSTRACT: We identified a human multiprotein complex (WINAC) that directly interacts with the vitamin D receptor (VDR) through the Williams syndrome transcription factor (WSTF). WINAC has ATP-dependent chromatin-remodeling activity and contains both SWI/SNF components and DNA replication-related factors. The latter might explain a WINAC requirement for normal S phase progression. WINAC mediates the recruitment of unliganded VDR to VDR target sites in promoters, while subsequent binding of coregulators requires ligand binding. This recruitment order exemplifies that an interaction of a sequence-specific regulator with a chromatin-remodeling complex can organize nucleosomal arrays at specific local sites in order to make promoters accessible for coregulators. Furthermore, overexpression of WSTF could restore the impaired recruitment of VDR to vitamin D regulated promoters in fibroblasts from Williams syndrome patients. This suggests that WINAC dysfunction contributes to Williams syndrome, which could therefore be considered, at least in part, a chromatin-remodeling factor disease.
    Cell 07/2003; 113(7):905-17. · 31.96 Impact Factor
  • Akifumi Tokita
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    ABSTRACT: Osteoporosis is a common disease with a strong genetic factors. Twin studies have shown that genetic factors play an important role in regulating bone turnover and bone mineral density. These phenotypes are determined by the combined effects of several genes and environmental influences. A great deal of research has been done on candidate genes, among the best studied are vitamin D receptor gene. From a clinical standpoint, advances in knowledge about the prospect of developing genetic markers for the assessment of fracture risk will be used as targets for the design of new drugs for the prevention and treatment of osteoporosis.
    Nippon rinsho. Japanese journal of clinical medicine 03/2003; 61(2):193-9.
  • Clinical calcium 11/2002; 12(10):1446-9.
  • Akifumi Tokita
    Nippon rinsho. Japanese journal of clinical medicine 04/2002; 60 Suppl 3:98-105.
  • Akifumi Tokita, Ken Hisada, Kyoko Nishizawa
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    ABSTRACT: In humans, the vitamin D receptor (VDR) gene has been localized to the chromosomal locus 12q13-14. The gene is composed of a minimum of nine exons. Hereditary 1,25-dihydroxyvitamin D resistant rickets (HVDRR) known as vitamin D dependent rickets type II is a rare autosomal recessive disease that arises as a result of mutations in the gene encoding the VDR. Genetic factors play a key role in determining bone mass, which is an important predictor of osteoporosis. Recently, polymorphism at the VDR locus has been implicated as a genetic marker for bone mineral density. Vitamin D receptor gene start codon polymorphisms, and 3'-end region polymorphisms may modulate bone density.
    Nippon rinsho. Japanese journal of clinical medicine 03/2002; 60(2):385-90.
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    ABSTRACT: Although some studies have reported a relationship between several candidate polymorphic genes and bone mineral density (BMD), little is known concerning the genetic factors influencing BMD in children. This study examined this relationship in healthy Japanese girls (n=125; age, 13.4 +/- 0.89 years; range, 12-15 years). We investigated allelic variants of the vitamin D receptor (VDR) gene, the estrogen receptor (ER) gene, the parathyroid hormone (PTH) gene, the Ca-sensing receptor (CaSR) gene, and the beta3-adrenergic receptor (beta3-AR) gene. The genotype of the VDR gene (Fok I) correlated with lumbar spine, and femoral neck BMD. The PTH polymorphisms (BstB I, Dra II) were also associated with lumbar spine BMD. No relationship was found between genotypes of the ER gene, CaSR gene, or beta3-AR gene and BMD. The age, height, weight, and body mass index did not differ significantly among girls with different VDR and PTH genotypes. These results suggest that the Fok I polymorphism of the VDR gene and the Dra II polymorphism of the PTH gene are risk factors for low bone density in Japanese girls.
    Journal of Bone and Mineral Metabolism 02/2002; 20(3):164-9. · 2.22 Impact Factor
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    ABSTRACT: Osteoporosis recently has been added to growing list of medical complications assisted with eating disorder in particular Anorexia nervosa. These often occur early in the course of anorexia in adolescent girls, presumably because this disorder not only interrupts the normal rapid bone accretion characteristic of adolescences, but also accelerate bone loss. The pathogenesis of osteoporosis in AN has not been completely characterized. While low body mass and amenorrhea are clearly important variables, other focters also may be involved. Some possible contributing factors in patients with AN include low Ca intake, increased glucocorticoids, insulin growth factor 1 deficiency. Simple weight gain needs to be part of the treatment, although it and exercise remain of unproven benefit for osteoporosis in patients with AN. But some studies have found that the clinical course of osteoporosis is not reversed simply with weight restoration. Long term studies are needed to answer the question of whether osteoporosis assisted with eating disorder is reversible.
    Nippon rinsho. Japanese journal of clinical medicine 04/2001; 59(3):554-60.
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    ABSTRACT: A highly sensitive single-stranded conformation polymorphism method for analysis of Vitamin D receptor (VDR) gene polymorphism was developed employing laser-induced fluorescence capillary electrophoresis (LIF-CE). LIF-CE was conducted utilizing a linear polyacrylamide solution as entangled polymer and acridine orange as a fluorescent dye of single-stranded DNA. Effect of acridine orange, size of PCR product and running temperature were investigated by LIF-CE in order to analyze the two polymorphisms of the allelic variation of the Bsm I and Taq I sites in intron 8 and exon 9, respectively, of the VDR gene. The developed method was simple, rapid (<16 min for Taq I type, <20 min for Bsm I type) and highly sensitive for VDR gene polymorphism. VDR gene polymorphism in 32 subjects was determined by the proposed method. The results were consistent with those obtained by restriction fragment-length polymorphism (RFLP) analysis using gel electrophoresis. The proposed method can be employed among the various VDR gene polymorphism analyses related to osteoporosis.
    Analytica Chimica Acta 01/2001; 445(2):197-204. · 4.39 Impact Factor

Publication Stats

2k Citations
337.13 Total Impact Points

Institutions

  • 1988–2007
    • Juntendo University
      • • Department of Paediatrics
      • • Department of Obstetrics and Gynecology
      • • Department of Medicine
      Edo, Tōkyō, Japan
  • 1989–2005
    • The University of Tokyo
      • • Institute of Molecular and Cellular Biosciences
      • • Department of Pediatrics
      Tokyo, Tokyo-to, Japan
  • 1999
    • Osaka Medical Center and Research Institute for Maternal and Child Health
      Izumi, Ōsaka, Japan
  • 1995
    • Kuopio University Hospital
      • Department of Surgery
      Kuopio, Eastern Finland Province, Finland
  • 1994
    • Garvan Institute of Medical Research
      • Cancer Research Program
      Darlinghurst, New South Wales, Australia