Publications by authors named "Koo Nagasawa"

Introduction: Atopic dermatitis (AD) is a chronic inflammatory skin condition that impairs the quality of life of affected paediatric patients and their families. Dupilumab, an antagonist of the shared alpha chain subunit of the cytokines interleukin-4 and interleukin-13, has revolutionised the management of moderate-to-severe AD by effectively targeting type 2 inflammation. However, live attenuated vaccines, including live attenuated influenza vaccines (LAIVs), are contraindicated during dupilumab therapy owing to limited safety data.

View Article and Find Full Text PDF

Probiotics such as bifidobacteria have been given to low-birth-weight neonates (LBWNs) at risk for a disrupted gut microbiota leading to the development of serious diseases such necrotizing enterocolitis. Recently prebiotics such as lactulose are used together with bifidobacteria as synbiotics. However, faster and more powerful bifidobacteria growth is desired for better LBWN outcomes.

View Article and Find Full Text PDF

Objectives: In Japan, population-based epidemiological data on respiratory syncytial virus (RSV) infections are limited. To elucidate the epidemiology of RSV before the introduction of new prophylactic drugs, we conducted a population-based study during and after the SARS-CoV-2 pandemic.

Methods: This study was performed in four hospitals in Chiba City and three hospitals in Ichihara City.

View Article and Find Full Text PDF

Pediatric myelodysplasia syndrome is often characterized by hypoplastic bone marrow morphology and predisposition to infection. Invasive aspergillosis during hematopoietic stem cell transplantation poses a significant threat and often requires voriconazole (VRCZ) therapy. However, difficulties in achieving appropriate VRCZ blood levels due to drug interactions have prompted the exploration of alternative treatments, such as isavuconazole (ISCZ).

View Article and Find Full Text PDF

The members of the Japanese Society for Pediatric Infectious Diseases and the Japanese Society of Pediatric Pulmonology have developed Guidelines for the Management of Respiratory Infectious Diseases in Children with the objective of facilitating appropriate diagnosis, treatment and prevention of respiratory infections in children. The first edition was published in 2004 and the fifth edition was published in 2022. The Guideline 2022 consists of 2 parts, clinical questions and commentary, and includes general respiratory infections and specific infections in children with underlying diseases and severe infections.

View Article and Find Full Text PDF

Molecular interactions between respiratory syncytial virus (RSV) fusion protein (F protein) and the cellular receptor Toll-like receptor 4 (TLR4) and myeloid differentiation factor-2 (MD-2) protein complex are unknown. Thus, to reveal the detailed molecular interactions between them, in silico analyses were performed using various bioinformatics techniques. The present simulation data showed that the neutralizing antibody (NT-Ab) binding sites in both prefusion and postfusion proteins at sites II and IV were involved in the interactions between them and the TLR4 molecule.

View Article and Find Full Text PDF

Unusual DS-1-like intergenogroup reassortant rotaviruses with a bovine-like G8 genotype (DS-1-like G8P [8] rotaviruses) have emerged and rapidly spread in several countries. In this study, the nucleotide sequences of seven human rotavirus G8P [8] strains in 2017 and 2019 in Japan were determined using viral metagenomics. Its genomic constellation (VP7-VP4-VP6-VP1-VP2-VP3-NSP1-NSP2-NSP3-NSP4-NSP5 genes) was defined as G8-P [8]-I2-R2-C2-M2-A2-N2-T2-E2-H2.

View Article and Find Full Text PDF

Parechovirus-A3 (PeV-A3), first reported in 2004 in Japan, is an emerging pathogen that causes sepsis and meningoencephalitis in neonates and young infants. Although PeV-A3 has been identified worldwide, its epidemiological characteristics differ by region. To investigate the molecular evolution and epidemiology of PeV-A3, we performed genetic analyses of 131 PeV-A3 strains from the years 1997-2019 in Niigata, Japan.

View Article and Find Full Text PDF

Introduction: Respiratory syncytial virus (RSV) is one of the most common causes of lower respiratory tract infections in children aged <5 years and is associated with long-term respiratory morbidities such as recurrent wheezing and asthma, decreased lung function, and allergic sensitization. The objective of this review was to evaluate the epidemiology and burden of RSV infection in the pediatric population in Japan.

Methods: Studies indexed in PubMed and ICHUSHI databases during January 2010-December 2020 were manually reviewed.

View Article and Find Full Text PDF

In Japan's Kanto region, the number of serovar Chester infections increased temporarily between 2014 and 2016. Concurrently with this temporal increase in the Kanto region, . Chester isolates belonging to one clonal group were causing repetitive outbreaks in Europe.

View Article and Find Full Text PDF

To elucidate the evolution of human respirovirus 3 (HRV3), we performed detailed genetic analyses of the gene (full-length) detected from hundreds of HRV3 strains obtained from various geographic regions. First, we performed time-scaled evolutionary analyses using the Bayesian Markov chain Monte Carlo method. Then, we performed analyses of phylodynamics, similarity, phylogenetic distance, selective pressure, and conformational B-cell epitope with the F-protein structural analyses.

View Article and Find Full Text PDF

Noroviruses are a major cause of viral epidemic gastroenteritis in humans worldwide. The protease (Pro) encoded in open reading frame 1 (ORF1) is an essential enzyme for proteolysis of the viral polyprotein. Although there are some reports regarding the evolutionary analysis of norovirus GII-encoding genes, there are few reports focused on the region.

View Article and Find Full Text PDF
Article Synopsis
  • Human respirovirus 3 (HRV3) causes acute respiratory infections and can lead to recurrent infections, though the reasons are unclear.
  • A study analyzed the hemagglutinin-neuraminidase (HN) gene of HRV3 across multiple countries, revealing a common ancestor with bovine respirovirus 3 dating back to around 1815 and noted the evolutionary rate of the gene.
  • The research identified various selection pressures on the HN protein and found that predicted B cell epitopes were mostly not aligned with neutralization sites, potentially explaining the virus's ability to reinfect humans.
View Article and Find Full Text PDF
Article Synopsis
  • Human norovirus GII.P17-GII.17 emerged in 2014, causing global gastroenteritis outbreaks, with significant evolutionary changes noted over the years.
  • Analysis of samples from 2013-2017 revealed that the GII.17 region diverged in 1949 and GII.P17 in 2010, with varied evolutionary rates indicating significant genomic changes.
  • Variants of the virus show potential changes in antigenicity, host interaction, and replication capabilities due to specific amino acid substitutions in key proteins, which could affect how the virus functions and spreads.
View Article and Find Full Text PDF

Panton Valentine Leukocidin (PVL) is one of the many toxins produced by Staphylococcus aureus. In Japan, PVL-positive S. aureus strains are mainly methicillin-resistant S.

View Article and Find Full Text PDF

Koplik spots are considered a disease-specific sign for measles, although comprehensive virological studies have not been conducted to date. In Japan, a national survey of 3023 measles and measles-suspected cases was conducted between 2009 and 2014 using polymerase chain reaction (PCR) or reverse transcription PCR (RT-PCR) to detect various rash/fever-associated viruses. Koplik spots were observed in 717 of 3023 cases (23.

View Article and Find Full Text PDF

Noroviruses are the leading cause of viral gastroenteritis in humans across the world. RNA-dependent RNA polymerase (RdRp) plays a critical role in the replication of the viral genome. Although there have been some reports on a limited number of genotypes with respect to the norovirus evolution of the region, no comprehensive molecular evolution examination of the norovirus GII genotype has yet been undertaken.

View Article and Find Full Text PDF

Seven foodborne norovirus outbreaks attributable to the GII.P17-GII.17 strain were reported across Japan in 2017, causing illness in a total of 2,094 persons.

View Article and Find Full Text PDF

We performed detailed genetic analyses of the partial hemagglutinin-neuraminidase (HN) gene in 34 human respirovirus 3 (HRV3) strains from children with acute respiratory illness during 2013-2015 in Iwate Prefecture, Japan. In addition, we performed analyses of the evolutionary timescale of the gene using the Bayesian Markov chain Monte Carlo (MCMC) method. Furthermore, we analyzed pairwise distances and performed selective pressure analyses followed by linear B-cell epitope mapping and N-glycosylation and phylodynamic analyses.

View Article and Find Full Text PDF

In the 2016/2017 winter season in Japan, HuNoV GII.P16-GII.2 strains (2016 strains) emerged and caused large outbreaks of acute gastroenteritis.

View Article and Find Full Text PDF

During the 2016-17 winter season in Japan, human norovirus GII.P16-GII.2 strains (2016 strains) caused large outbreaks of acute gastroenteritis.

View Article and Find Full Text PDF

Human norovirus (HuNoV) is a leading cause of viral gastroenteritis worldwide, of which GII.4 is the most predominant genotype. Unlike other genotypes, GII.

View Article and Find Full Text PDF

Two live attenuated oral rotavirus vaccines, Rotarix and RotaTeq, have been introduced as voluntary vaccination in Japan since 2011 and 2012, respectively. Effectiveness of the vaccines has been confirmed, whereas concerns such as shedding of the vaccine strains and gastroenteritis cases caused by vaccine strains are not well assessed. We aimed to identify the vaccine strains in children with acute gastroenteritis (AGE) to investigate the prevalence of AGE caused by vaccination or horizontal transmission of vaccine strains.

View Article and Find Full Text PDF