Katsura Igai

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Infection with Shiga toxin (Stx)-producing Escherichia coli O157:H7 causes bloody diarrhea and hemorrhagic colitis in humans, sometimes resulting in fatal systemic complications. Among the known Stx family members, Stx2 is responsible for the most severe forms of disease. Stx2 binds to target cells via multivalent interactions between its B-subunit pentamer(More)
Shiga toxin (Stx) is a major virulence factor in infection with Stx-producing Escherichia coli (STEC). We developed a series of linear polymers of acrylamide, each with a different density of trisaccharide of globotriaosylceramide (Gb3), which is a receptor for Stx, and identified Gb3 polymers with highly clustered trisaccharides as Stx adsorbents(More)
We previously developed linear polymers bearing clustered trisaccharides of globotriaosylceramide (Gb3) as orally applicable Shiga toxin (Stx) neutralizers. Here, using a Gb3 polymer with a short spacer tethering the trisaccharide to the core, we found that shortening the spacer length markedly reduced the binding affinity for Stx2 but not Stx1. Moreover,(More)
Shiga toxin (Stx) is a major virulence factor of Stx-producing Escherichia coli. Recently, we developed a therapeutic Stx neutralizer with 6 trisaccharides of globotriaosyl ceramide, a receptor for Stx, in its dendrimer structure (referred to as "SUPER TWIG [1]6") to function in the circulation. Here, we determined the optimal structure of SUPER TWIG for it(More)
OBJECTIVES We present new nitrogen isotopic discrimination factor between diets and scalp hairs (Δ(15) NHair-Diet : δ(15) NHair - δ(15) NDiet ) for indigenous residents in three communities in the Papua New Guinea Highlands who consumed various amounts and qualities of protein. The Δ(15) N is important for precise evaluation of the dietary habits of human(More)
OBJECTIVES The aim of this article was to develop a semi-quantitative food frequency questionnaire (FFQ) and evaluate its validity to estimate habitual protein intake, and investigate current dietary protein intakes of Papua New Guinea (PNG) Highlanders. METHODS A 32-item FFQ was developed and tested among 135 healthy male and female volunteers. The(More)
The dialyzer for Shiga-toxin elimination was developed and its performance was established. The dialyzer was prepared by immobilization of multivalent ligands. Glycoconjugate polymers having oligosaccharides and amino groups were synthesized to function as Shiga-toxin adsorbents. The amino group was utilized to immobilize the polymer inside the cellulose(More)
Stool samples were collected from 148 healthy adults living a traditional subsistence lifestyle in Papua New Guinea and screened for enteric pathogens using real-time RT-PCR/PCR assays. Enteric pathogens were detected in a high proportion (41%) of individuals. Clear differences were observed in the detection of pathogens between highland and lowland(More)
Adequate amount of proteins from foods are normally needed to maintain muscle mass of the human body. Although protein intakes of Papua New Guinea (PNG) highlanders are less than biologically adequate, protein deficiency related disorders have rarely been reported. It has been postulated that gut microbiota play a role in such low-protein-adaptation. To(More)
It has been hypothesized that nitrogen fixation occurs in the human gut. However, whether the gut microbiota truly has this potential remains unclear. We investigated the nitrogen-fixing activity and diversity of the nitrogenase reductase (NifH) genes in the faecal microbiota of humans, focusing on Papua New Guinean and Japanese individuals with low to high(More)
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