KEIO RESEARCHERS INFORMATION SYSTEM

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• Vaginal microbiota composition in pregnant women following cervical conization and radical trachelectomy

  Hasegawa K., Kasuga Y., Ohnishi E., Nakabayashi K., Kamura H., Otani T., Ikenoue S., Hata K., Tanaka M.

  Scientific Reports 16 ( 1 )  2026.12

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  We aimed to provide a comparative analysis of the vaginal microbiota in pregnant women who underwent cervical conization (CZ) and radical trachelectomy (RT) for cervical intraepithelial neoplasia or early-stage cervical cancer. We included 114 pregnant Japanese women who underwent CZ group (n = 13), RT group (n = 20), or received no cervical treatments (CON group: n = 81) and cared at Keio University Hospital between 2019 and 2023. The differences in vaginal microbiota during the first, second, and third trimester using V1–V2 region of the 16S ribosomal RNA were investigated. Higher species diversity was observed in the CZ and RT groups than in the CON group; however, the abundance and composition of Lactobacillus were similar. The rate of preterm delivery in women who underwent cervical treatments was significantly higher than that in those who had full-term delivery; however, the species diversity and abundance or composition of Lactobacillus was not associated with preterm birth. Women who underwent CZ or RT had higher microbial species diversity than women who did not undergo a procedure; however, Lactobacillus abundance and composition remained the same. The cause of preterm delivery in women who received cervical treatment was not associated with Lactobacillus species diversity or abundance.

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• Associations Between Late-Night Shift Work and Perinatal Outcomes: A Nationwide Cross-Sectional Study Using JACSIS and JASTIS Data

  Tanaka Y., Kasuga Y., Hosokawa Y., Tamai J., Fukuma Y., Otani T., Fukutake M., Ikenoue S., Tabuchi T., Tanaka M.

  Journal of Obstetrics and Gynaecology Research 52 ( 2 )  2026.02

  ISSN  13418076

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  Aim: This study investigated associations between late-night shift work and perinatal outcomes. Methods: Participants were pregnant women with recorded perinatal outcomes (late-night shift group, 626 cases; non-late-night shift group, 6633 cases) identified from two Japanese Internet surveys. We analyzed the association between late-night shift work and adverse perinatal outcomes. Furthermore, we examined factors associated with the use of Maternal Health Management and Guidance Cards. Results: The late-night shift group had significantly higher rates of threatened miscarriage, premature rupture of membranes (PROM), use of the Maternal Health Management and Guidance Card, health problems requiring hospitalization, fetal health problems, and infectious diseases compared with the non-late-night shift group. However, other perinatal outcomes, including preterm birth, gestational age at delivery, mode of delivery, and birth weight, did not differ significantly between groups. Among late-night shift-working mothers, those who used the Maternal Health Management and Guidance Card had a higher incidence of hyperemesis gravidarum, threatened miscarriage, and preterm labor than those who did not. Conclusions: Late-night shift work during pregnancy may be associated with an increased risk of perinatal complications. The Maternal Health Management and Guidance Card may provide support for pregnant women engaged in late-night shift work.

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• Serial sonographic reversal of parvovirus B19-induced hydrops fetalis after two intrauterine transfusions

  Abe Y., Ikenoue S., Otani T., Fukutake M., Kasuga Y., Tanaka M.

  Journal of Medical Ultrasonics Singapore  2026

  ISSN  13464523

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• ARID1A gene variants and fetal hydrocephalus: First evidence of mRNA decay escape

  Tanaka Y., Yamada M., Miya F., Otani T., Kasuga Y., Suzuki H., Inagaki N., White S.M., Tanaka M., Kosaki K.

  European Journal of Medical Genetics 78 2025.12

  ISSN  17697212

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  Germline variants in ARID1A have been associated with the so-called BAFopathies, including Coffin-Siris syndrome, which is characterized by hypertrichosis, short fifth finger, thin upper lip, and thick lower lip, is associated with a unique episignature. Hydrocephalus has not been considered part of BAFopathy until recently, when ARID1A variants were implicated in prenatal-onset hydrocephalus. It remains unknown whether ARID1A-associated hydrocephalus is linked to a specific class of variants and whether it exhibits an episignature comparable to that of BAFopathies. We conducted genomic and epigenomic analyses on a fetus diagnosed with severe hydrocephalus on prenatal ultrasound at 19 weeks. After detailed genetic counseling, the pregnancy was terminated at 21 weeks. The delivered fetus exhibited short fifth fingers, thin upper lip, and thick lower lip. Postmortem exome sequencing using umbilical cord blood identified a de novo heterozygous frameshift variant in the last exon of ARID1A (NM_006015.6:c.5259_5262dupGTCT, p.(Ser1755Valfs∗2)). The frameshift variant in the last exon was expected to escape nonsense-mediated mRNA decay (NMD), and we did confirm this through RNA-seq. Concurrent episignature analysis by nanopore sequencing and a support vector machine-based classifier showed that the fetus maps to the BAFopathy group rather than a separate position on the UMAP. Genotype-phenotype correlation analysis of unpublished data from previous reports regarding hydrocephalus and potential NMD escape, with input from the original authors, indicated that the association remains ambiguous. Hence, ARID1A-associated hydrocephalus occurs within the broader clinical and epigenomic spectrum of BAFopathies, but a distinct genetic mechanism caused by NMD escape is unlikely to play a role.

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• Oral, Vaginal, and Placental Microbiota Profiles in Japanese Pregnancies with Preterm Birth and Chronic Abruption-Oligohydramnios Sequence (CAOS): A Cross-Sectional Study

  Fukuma Y., Kasuga Y., Akita K., Tamai J., Tanaka Y., Hasegawa K., Otani T., Fukutake M., Ikenoue S., Morikawa S., Nakagawa T., Ishihara K., Tanaka M.

  Medicina Lithuania 61 ( 12 )  2025.12

  ISSN  1010660X

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  Background and Objectives: Preterm birth (PTB) imposes a substantial medical and economic burden on perinatal care. Recent advances in 16S rRNA gene sequencing help detailed microbiota analysis. Understanding microbiota’s contribution may help in understanding PTB pathogenesis. We aim to investigate the microbiota profiles of the oral, vaginal, and placental microbiota in pregnant Japanese women hospitalized for care of preterm labor and examine the association between them and perinatal outcomes. Materials and Methods: This cross-sectional study included 20 pregnant Japanese women admitted to a single perinatal center for preterm labor between 2022 and 2023. Oral, vaginal, and placental samples were collected aseptically during hospitalization. The patients were retrospectively categorized into: term birth (TB, n = 10), chronic abruption-oligohydramnios sequence (CAOS, n = 3), and PTB without CAOS (PTB, n = 7) perinatal outcomes. Microbiota profiles were analyzed using 16S rRNA gene sequencing, and group comparisons were performed using univariate statistical methods. Results: Alpha or beta diversity of the oral and vaginal microbiota among the three groups did not differ significantly. CAOS and PTB groups showed a trend toward altered vaginal microbial composition, but not the TB group. In the placental microbiota, beta diversity differed significantly among the TB, PTB, and CAOS groups. Ureaplasma urealyticum was more abundant in the PTB group, whereas Ureaplasma parvum was more abundant in the CAOS group. Conclusions: A potential shift in the vaginal microbiota and alterations in the placental microbiota, observed in PTB, including CAOS, suggested a possible microbial contribution.

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Papers, etc., Registered in KOARA 【 Display / hide 】

Papers, etc., Registered in KOARA 【 Display / hide 】

• 低酸素性虚血性脳症モデルマウスに対するヒト羊水幹細胞慢性期投与の神経回復効果

  Ōtani, Toshimitsu

  (慶應義塾大学大学院医学研究科)  2019

• 低酸素性虚血性脳症モデルマウスに対するヒト羊水幹細胞慢性期投与の神経回復効果

  Ōtani, Toshimitsu

  (慶應義塾大学大学院医学研究科)  2019

• 低酸素性虚血性脳症モデルマウスに対するヒト羊水幹細胞慢性期投与の神経回復効果

  Ōtani, Toshimitsu

  (慶應義塾大学大学院医学研究科)  2019

Courses Taught 【 Display / hide 】

Courses Taught 【 Display / hide 】

• LECTURE SERIES, OBSTETRICS

  2026