Publications by authors named "Koushi Yamaguchi"

Article Synopsis
  • - Reports have indicated potential cardiovascular issues, particularly thrombosis, linked to mRNA vaccines for COVID-19, raising concerns about their safety.
  • - A study of 184 hospital staff showed a significant increase in anti-phosphatidylethanolamine antibodies after vaccination, which are often associated with pregnancy complications.
  • - Despite these findings, there were no notable changes in other antibody levels, and the relationship between vaccination and health risks like thrombosis or pregnancy loss is still unclear, indicating a need for further research.
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Some of obstetrical complications such as unexplained pregnancy loss and preeclampsia (PE) are associated with maternal-fetal immune abnormalities, leading to uteroplacental dysfunction, insufficient fetal immune tolerance, or fetal rejection. Immunosuppressants with calcineurin inhibitors could be useful for the prevention of these complications by modulating the cellular immune balance by directly inhibiting activated T-helper (Th) 1 and natural killer (NK)/NKT cells. We present our experience with the immunosuppressant tacrolimus in five pregnant women who had a previous pregnancy history of unexplained or preeclamptic stillbirth.

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Introduction: Infertility is estimated to affect 8% to 12% of reproductive-aged couples worldwide. While approximately 85% of infertile couples have an identified cause, the remaining 15% suffer physically and emotionally from unexplained intractable infertility. In recent years, maternal-to-fetal immunological abnormalities have attracted attention as mechanisms that differ from the conventional factors contributing to infertility and pregnancy loss.

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Article Synopsis
  • Patients with underlying medical conditions are at a higher risk for severe COVID-19 symptoms, making it crucial to assess their immune response to vaccines for tailored vaccination strategies.
  • A study involving 2,762 healthcare workers evaluated IgG antibody levels post-vaccination, revealing that individuals with treated hypertension and diabetes had significantly lower antibody titers than those without these conditions.
  • No major differences in antibody levels were noted for chronic lung disease, cardiovascular disease, or cancer, indicating that hypertension and diabetes may impact vaccine effectiveness for certain patients.
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Background: Discrimination is an important determinant of negative mental health outcomes. This study determined the association between the experience of COVID-19-related discrimination and psychological distress among healthcare workers (HCWs) in Japan.

Methods: This cross-sectional study conducted a health survey among 5703 HCWs of six national medical and research centers in Japan from October 2020 to March 2021.

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An increasing number of countries have been introducing acellular pertussis vaccination during pregnancy for the prevention of neonatal pertussis. In response to the fact that infantile pertussis cases of 0-5 months age groups remained unchanged despite the universal vaccination program, prenatal pertussis vaccination has been a rising issue in Japan. Hence, we investigated the seroprevalence of pertussis, diphtheria, and tetanus antibodies in Japanese pregnant women and neonates, and evaluated the necessity of diphtheria-tetanus-acellular pertussis (DTaP) vaccination during the preconception or prenatal period.

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Vaccine literacy of healthcare workers (HCWs) may affect the COVID-19 vaccine uptake of the general population. This study aimed to clarify the vaccine literacy level of HCWs in Japan and its impacts on their concerns about vaccines and intention to recommend that others receive vaccines. This cross-sectional survey was conducted in July 2021 based on the recruitment of HCWs in a pediatric and maternity hospital and research center in Tokyo, Japan.

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Background: Information regarding effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant strains on clinical manifestations and outcomes of coronavirus disease 2019 (COVID-19) in pregnant women is limited.

Methods: A retrospective observational study was conducted using the data from the nationwide COVID-19 registry in Japan. We identified pregnant patients with symptomatic COVID-19 hospitalized during the study period.

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The effect of heated tobacco products (HTPs) use and moderate alcohol drinking on immunogenicity to coronavirus disease (COVID-19) vaccines remain elusive. This study aimed to examine the association of tobacco product use and alcohol consumption with anti-SARS-CoV-2 spike IgG antibody titers after the BNT162b2 vaccine. Participants were 3433 healthcare workers receiving two vaccine doses in the 4 national centers for advanced medical and research in Japan.

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Background: Although higher rates of burnout have been reported during the COVID-19 pandemic, the contribution of the modifiable factors is lesser-known. We investigated how the risk of emotional exhaustion was associated with mindfulness skills and social support in a single medical center in Japan.

Methods: We conducted a cross-sectional web survey on mental health for all staff of a national medical hospital from February to March 2021.

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Background: Several studies have investigated whether pregnancy is a risk factor for developing severe coronavirus disease 2019 (COVID-19); however, the results remain controversial. In addition, the information regarding risk factors for developing severe COVID-19 in pregnant women is limited.

Methods: A retrospective cohort study analyzing the data from the nationwide COVID-19 registry in Japan was conducted.

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Tacrolimus has received considerable attention as a treatment approach for infertility associated with maternal-foetal immune abnormalities, such as repeated implantation failure (RIF) and recurrent pregnancy loss (RPL). This study examined the changes in T-helper (Th) 1 and 2 cell populations during pregnancy in peripheral blood of tacrolimus-treated RIF patients who delivered a liveborn infant from August 2012 to February 2020 at the National Centre for Child Health and Development. A total of 58 eligible study subjects were divided into two groups according to the presence of a history of RPL: (i) RIF-alone group ( = 31); and (ii) RIF-plus-RPL group ( = 27).

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Problem: We aimed to assess whether an imbalance of T-helper (Th) 1 and Th2 cells contributes to implantation failure and pregnancy loss.

Method Of Study: In this cross-sectional study, 197 consecutive patients with a history of repeated implantation failure (RIF) after three or more embryo transfer (ET) cycles and/or recurrent pregnancy loss (RPL) after two or more clinical pregnancy losses underwent Th cell testing. After excluding 42 women aged ≥44 and 9 with vitamin D supplementation, we recruited 146 women including 79 with RIF and 81 with RPL.

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A 34-year-old woman (gravida 1, para 0) visited the Division of Reproductive Medicine/National Center for Child Health and Development due to infertility; she had also been suffering from incompletely treated genital ulcers and stomatitis for 10 years. This case was diagnosed as an incomplete-type Behçet's disease (BD) at the Department of Maternal-Fetal Biology/National Center for Child Health and Development. Since no apparent abnormality was found in the general infertility test, artificial insemination with the husband's semen (AIH) was performed for the patient with unexplained infertility, which failed.

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Article Synopsis
  • Pregnant women face a higher risk of severe illness from influenza, prompting recommendations for prioritizing their vaccination at any stage of pregnancy due to limited knowledge about timing.
  • This study aimed to assess the effect of vaccination timing on the immune response in mothers and how well antibodies are transferred to newborns.
  • Results from 16 studies indicated that women who received the vaccine in later trimesters had significantly higher immune responses and antibody levels in their newborns compared to those vaccinated earlier.
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Problem: Previously, we reported the clinical efficacy of tacrolimus in women with repeated implantation failures (RIF) of immune etiologies. Safety of tacrolimus in pregnant women has been reported in women with organ transplantations. However, the safety of tacrolimus for women with RIF undergoing assisted reproductive technology cycles and their babies has not been reported prior.

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A Rho-incompatible pregnancy induces anemia in the fetus and can ultimately lead to fetal hydrops and intrauterine fetal death. A patient who had experienced recurrent implantation failures following a first successful delivery finally succeeded in achieving a second pregnancy via the use of tacrolimus. The second pregnancy was Rho-incompatible.

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Many approaches have been used to achieve successful pregnancies in patients with infertility, though existing treatments remain unsatisfactory in patients with infertility caused by abnormal maternal-fetal immunity. However, our understanding of the immunological aspects of infertility has steadily progressed, aided by recent research into organ transplantation and cancer. The results of these recent analyses have led to the development and evaluation of several candidate immunological treatments, but the use of immunological treatments remains a novel approach.

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Aim: An immune etiology for idiopathic recurrent miscarriage is an important issue because a fetus is allogenetically different from the mother. Type 1 T helper (Th1) and Type 2 (Th2) cells have important functions in immune responses and there is a general agreement that pregnancy is associated with Th2 cell dominance. The purpose of this case report is to establish the effectiveness of an immunosuppressive treatment for a patient who had 11 consecutive miscarriages despite several treatments, such as anticoagulation, that showed elevated Th1/Th2 cell ratios.

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Article Synopsis
  • Chronic histiocytic intervillositis (CHI) is a rare condition linked to severe pregnancy complications and often recurs.
  • A case study of a patient with a history of early miscarriages shows three consecutive pregnancies affected by CHI, each managed with different treatment protocols.
  • Treatments with heparin and immunosuppressive therapy appeared more effective, as both led to live births, while the significance of elevated alkaline phosphatase levels was deemed clinically unimportant.
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Problem: We aim to investigate whether the peripheral blood T helper (Th) 1 cell level could predict pregnancy outcome in patients who have experienced repeated implantation failure (RIF, three or more) after ART cycles.

Method Of Study: This is a prospective cohort study of total 124 women with RIF who showed elevated Th1/Th2 (CD4 IFN-γ /CD4 IL-4 ) cell ratios (≥10.3) and received tacrolimus at Sugiyama Clinic between November 2011 and July 2016.

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