Publications by authors named "Hamajima T"

Beam-divergence characteristics of single negative ion beamlet have been experimentally investigated with a superimposition of a controlled perturbation of a radio frequency wave (RF) field in a filament-arc discharge negative ion source. Oscillations of a negative-ion beamlet width and axis responding to the RF perturbation were observed, which may be a cause of the larger beam divergence angle of the RF negative ion source for ITER. It is pointed out that the oscillation of the beamlet width depends on the perveance and on an RF frequency such that the oscillation is suppressed at perveance-matched conditions and at low RF frequency.

View Article and Find Full Text PDF

Introduction: Precocious puberty (PP), which is sometimes divided into gonadotropin-dependent or gonadotropin-independent PP, is a pathological condition characterized by premature secretion of gonadal steroids resulting in the early development of secondary sexual characteristics. Girls younger than 6 years with idiopathic gonadotropin-dependent PP (referred to as central PP or CPP) who receive gonadotropin-releasing hormone analog (GnRHa) therapy experience an increase in their adult height (AH) in contrast to girls who are aged 6 years or more, who show no consistent pattern of increase even with GnRHa therapy.

Methods: In total, 133 girls aged 6 years or more who visited any one of the seven study centers between April 2000 and March 2020 and who met the diagnostic criteria for PP in Japan were retrospectively examined.

View Article and Find Full Text PDF
Article Synopsis
  • Burosumab is a new medication designed for treating disorders related to hereditary fibroblast growth factor 23 (FGF23), specifically hypophosphatemia.
  • An 11-year-old girl with McCune-Albright syndrome suffered from low phosphate levels and multiple bone lesions due to excess FGF23, but her condition improved significantly with burosumab treatment.
  • This case marks the first instance of burosumab improving bone lesions in a patient with McCune-Albright syndrome, highlighting its potential therapeutic benefits.
View Article and Find Full Text PDF
Article Synopsis
  • Achondroplasia (ACH) is a genetic condition leading to short stature and distinctive physical features, with a high complication rate observed in young patients.
  • A study reviewing medical records of Japanese children with ACH under 5 years highlighted that 89.2% had complications, and a majority required surgical interventions.
  • Growth hormone treatment initiated at age 3 resulted in significant height increases compared to untreated patients, emphasizing the importance of early diagnosis and monitoring for effective management.
View Article and Find Full Text PDF

Central congenital hypothyroidism (CH) can occur as an isolated deficiency or as part of combined pituitary hormone deficiency. Unlike primary CH, central CH cannot be detected by newborn screening (NBS) using dry filter paper blood TSH levels, and early diagnosis remains challenging. In this study, the clinical and genetic backgrounds of patients with isolated central CH were determined through a questionnaire-based survey among members of the Japanese Society for Pediatric Endocrinology.

View Article and Find Full Text PDF

Introduction: The testicular regression syndrome (TRS) is a form of differences of sex development (DSD) in which the testes differentiate and function during early embryonic development, but subsequently regress. The clinical phenotype of TRS often overlaps with that of partial gonadal dysgenesis (PGD). Previous studies have demonstrated a causal association between TRS/PGD and heterozygous missense variants of DHX37.

View Article and Find Full Text PDF

Context: Adrenal crisis (AC) is a life-threatening complication that occurs during follow-up of patients with adrenal insufficiency (AI). No prospective study has thoroughly investigated AC in children with primary and secondary AI.

Objective: This work aimed to determine the incidence and risk factors for AC in patients with pediatric-onset AI.

View Article and Find Full Text PDF

Hyperphosphatemic familial tumoral calcinosis (HFTC) is a rare, inherited autosomal recessive disorder caused by fibroblast growth factor-23 (), N-acetylgalactosaminyltransferase 3 (), or Klotho () gene variants. Here, we report the case of a Japanese boy who presented with a mass in his left elbow at the age of three. Laboratory test results of the patient revealed normocalcemia (10.

View Article and Find Full Text PDF
Article Synopsis
  • - The study focuses on FGF23-related hypophosphatemic rickets (HPR), which causes low serum phosphorus levels and results in skeletal issues like lower limb deformities in children.
  • - Researchers evaluated the impact of burosumab, an antibody that targets FGF23, on the lower limb alignment of patients aged 15 or younger over a minimum of one year.
  • - Results showed improvement in lower limb deformities in 6 out of 10 limbs treated, particularly in younger patients with severe deformities, while older patients saw less improvement; no cases of deterioration were noted.
View Article and Find Full Text PDF

Mutations in transport and Golgi organization 2 homolog () have recently been described as a cause of an autosomal recessive syndrome characterized by episodes of metabolic crisis associated with rhabdomyolysis, cardiac arrhythmias, and neurodegeneration. Herein, we report a case of a one-and-a-half-year-old Japanese girl, born to nonconsanguineous parents, who presented with metabolic crisis characterized by hypoglycemia with hypoketonemia, rhabdomyolysis, lactic acidosis, and prolonged corrected QT interval (QTc) at the age of 6 months. Acylcarnitine analysis during the episode of crisis showed prominent elevation of C14:1, suggesting very-long-chain acyl-CoA dehydrogenase (VLCAD) deficiency.

View Article and Find Full Text PDF

Type 1 insulin-like growth factor receptor (IGF1R) plays an important role in normal fetal and postnatal growth. Over 30 pathogenic variants of have been identified in patients with short stature. Yet, 20 years after the first report, a variety of phenotypes remain poorly defined.

View Article and Find Full Text PDF
Article Synopsis
  • Monitoring 21-hydroxylase deficiency (21-OHD) is typically done using serum 17-hydroxyprogesterone (17OHP) levels, but urinary pregnanetriol (PT) may also be effective.
  • A study was conducted on 25 patients to examine the relationship between first morning urinary PT values and 17OHP levels at different times, particularly before and after glucocorticoid administration.
  • Results showed a strong correlation between first morning PT and 17OHP values prior to medication, suggesting that measuring PT could be a practical method for monitoring 21-OHD treatment.
View Article and Find Full Text PDF
Article Synopsis
  • - Complete androgen insensitivity syndrome (CAIS) results from mutations in the androgen receptor gene, presenting as a 46,XY karyotype with male gonads but normal female external genitalia.
  • - Although patients with CAIS have a low risk of gonadal tumors before puberty, that risk increases with age, and most tumors typically arise from germ cells rather than stromal cells.
  • - This report discusses a unique case of a CAIS patient who, at 8 years old, showed signs of early puberty due to a feminizing Sertoli cell tumor, which was confirmed after a gonadectomy at age 10.
View Article and Find Full Text PDF

Context: Lipoid congenital adrenal hyperplasia (LCAH) is caused by mutations in STAR. Classic (CLCAH) and nonclassic (NCLCAH) forms were reported as total and partial deficiencies, respectively, of adrenal and gonadal steroid hormones. The rarity of LCAH has precluded large-scale epidemiological and clinical investigations.

View Article and Find Full Text PDF
Article Synopsis
  • A randomized controlled trial in Japan aimed to assess the impact of walking on childhood obesity among elementary school children with a high percentage overweight (≥20%).
  • Participants were divided into three groups: one encouraged to walk at least 10,000 steps on school holidays, another to limit screen time, and a control group with no intervention, with a primary outcome of %OW reduction after three months.
  • Results showed that the walking group experienced a significant decrease in %OW (mean reduction of -4.06%) compared to the control group, suggesting that promoting walking can be an effective strategy for addressing obesity in children.
View Article and Find Full Text PDF

Chemical optimization of the 5,6,7,8-tetrahydropyrido[4,3-d]pyrimidine (THPP) scaffold was conducted with a focus on cellular potency while maintaining high selectivity against PI3K isoforms. Compound 11f was identified as a potent, highly selective and orally available PI3Kδ inhibitor. In addition, 11f exhibited efficacy in an in vivo antibody production model.

View Article and Find Full Text PDF

Chemical optimization of pyrazolopyridine 1, focused on cellular potency, isoform selectivity and microsomal stability, led to the discovery of the potent, selective and orally available PI3Kδ inhibitor 5d. On the basis of its desirable potency, selectivity and pharmacokinetic profiles, 5d was tested in the trinitrophenylated aminoethylcarboxymethyl-Ficoll (TNP-Ficoll)-induced antibody production model, and showed higher antibody inhibition than a 4-fold oral dose of the starting compound 1. These excellent results suggest that 5d is a potential candidate for further studies in the treatment of autoimmune diseases and leukocyte malignancies.

View Article and Find Full Text PDF

Phosphatidylinositol-3-kinase (PI3K)δ inhibition is one of the most attractive approaches to the treatment of autoimmune diseases and leukocyte malignancies. Through the exploration of pyrazolopyridine derivatives as potential PI3Kδ inhibitors, compound 12a was identified as a potent PI3Kδ inhibitor but suffered from poor oral exposure in mice. With a modified amide linkage group, compound 15a was developed as an orally available PI3Kδ inhibitor with reduced selectivity against other PI3Ks.

View Article and Find Full Text PDF

Background: Congenital hypogonadotropic hypogonadism (CHH) is classified as Kallmann syndrome (KS) with anosmia/hyposmia or normosmic (n)CHH. Here, we investigated the genetic causes and phenotype-genotype correlations in Japanese patients with CHH.

Methods: We enrolled 22 Japanese patients with CHH from 21 families (18 patients with KS and 4 with nCHH) and analyzed 27 genes implicated in CHH by next-generation and Sanger sequencing.

View Article and Find Full Text PDF
Article Synopsis
  • The study investigates the genetic causes of idiopathic short stature (ISS) and Leri-Weill dyschondrosteosis (LWD) in 328 Japanese patients, focusing on SHOX mutations and copy-number variations (CNVs).
  • Findings revealed that SHOX abnormalities were present in 3.8% of ISS and 50% of LWD cases, with specific CNVs but the common European deletion absent in the Japanese patients.
  • The results suggest that while SHOX mutations are similarly prevalent between Asian and European patients, there are unique genetic variances, and point mutations in conserved non-coding elements (CNEs) may have limited clinical significance.
View Article and Find Full Text PDF

Selenocysteine (Sec) insertion sequence-binding protein 2 (SBP2) is essential for the biosynthesis of Sec-containing proteins, termed selenoproteins. Subjects with mutations in the SBP2 gene have decreased levels of several selenoproteins, resulting in a complex phenotype. Selenoproteins play a significant role in antioxidative defense, and deficiencies in these proteins can lead to increased oxidative stress.

View Article and Find Full Text PDF

Pseudoautosomal region 1 (PAR1) contains SHOX, in addition to seven highly conserved non-coding DNA elements (CNEs) with cis-regulatory activity. Microdeletions involving SHOX exons 1-6a and/or the CNEs result in idiopathic short stature (ISS) and Leri-Weill dyschondrosteosis (LWD). Here, we report six rare copy-number variations (CNVs) in PAR1 identified through copy-number analyzes of 245 ISS/LWD patients and 15 unaffected individuals.

View Article and Find Full Text PDF

Objective: The type I insulin-like growth factor I receptor (IGF1R) plays an important role in growth. We aimed to evaluate the detailed mechanism underlying the effect of IGF1R on human growth.

Patients And Methods: We have performed sequence analysis of IGF1R in 55 patients with SGA short stature in Japan, since 2004, and identified novel heterozygous nonsense mutations in 2 patients: an 8-year-old Japanese boy (case 1), with a birthweight of 2228 g (-3·3 SDS) and height of 46 cm (-2·1 SDS), and a 3-year-old Japanese girl (case 2), with a birthweight of 2110 g (-3·0 SDS) and height of 44·3 cm (-2·8 SDS).

View Article and Find Full Text PDF

Study Question: What percentage of cases with non-syndromic hypospadias can be ascribed to mutations in known causative/candidate/susceptibility genes or submicroscopic copy-number variations (CNVs) in the genome?

Summary Answer: Monogenic and digenic mutations in known causative genes and cryptic CNVs account for >10% of cases with non-syndromic hypospadias. While known susceptibility polymorphisms appear to play a minor role in the development of this condition, further studies are required to validate this observation.

What Is Known Already: Fifteen causative, three candidate, and 14 susceptible genes, and a few submicroscopic CNVs have been implicated in non-syndromic hypospadias.

View Article and Find Full Text PDF

Objectives: Mutations in the dual oxidase 2 gene (DUOX2) is the most common genetic cause of congenital hypothyroidism (CH) in Japan. All previously described DUOX2 mutation-carrying families have followed autosomal recessive inheritance. We report a nonconsanguineous Japanese family harbouring biallelic DUOX2 mutations, which presented an apparently dominant inheritance of nonautoimmune hypothyroidism.

View Article and Find Full Text PDF