Publications by authors named "Takahiko Niwa"

Introduction: Carbon dioxide-dependent Proteus mirabilis has been isolated from clinical specimens. It is not clear whether mutations in carbonic anhydrase are responsible for the carbon dioxide dependence of P. mirabilis.

View Article and Find Full Text PDF

A small-colony variant (SCV) of carbon dioxide-dependent Escherichia coli was isolated from a patient with acute bacterial cystitis. After the urine sample was inoculated on 5% sheep blood agar and incubated overnight at 35 °C in ambient air, no colony formation was observed. However, after overnight incubation at 35 °C in 5% CO-enhanced ambient air, numerous colonies were obtained.

View Article and Find Full Text PDF

Introduction: Small-colony variants (SCVs) of bacteria are subpopulations with a small colony size, low growth rate, and atypical colony morphology. The purpose of this study was to comprehensively elucidate the characteristics and underlying mechanism of the development of a glutamine-dependent SCV of E. coli, GU-92, isolated from the blood of a patient with pyelonephritis.

View Article and Find Full Text PDF

This study sought to evaluate the effects of two vaccine doses and the extent of SARS-CoV-2 infection among healthcare workers. We measured immunoglobulin G antibody titers against SARS-CoV-2 nucleocapsid and spike protein among healthcare workers at Gunma University Hospital. In March 2021, prior to BNT-162b2 vaccination, two of 771 participants were seropositive for nucleocapsid and spike protein, whereas 768 were seronegative.

View Article and Find Full Text PDF

Objectives: To investigate potential functions of transforming growth factor-beta (TGF-β) isoforms in maturation-stage ameloblasts during amelogenesis.

Methods: In vivo activation of TGF-β was characterized by using matrix metalloproteinase 20 null (Mmp20) and wild-type (Mmp20) mice. Using mHAT9d cells cultured in the presence of each TGF-β isoform, (1) cell proliferation was determined by MTS assay, (2) immunostaining with anti-cleaved caspase-3 monoclonal antibody was performed and apoptotic indices were measured, (3) gene expression was analyzed by RT-qPCR, and (4) the uptake of amelogenin into mHAT9d cells was directly observed using a fluorescence microscope.

View Article and Find Full Text PDF

Vital pulp therapy (VPT) is to preserve the nerve and maintain healthy dental pulp tissue. Laser irradiation (LI) is beneficial for VPT. Understanding how LI affects dental pulp cells and tissues is necessary to elucidate the mechanism of reparative dentin and dentin regeneration.

View Article and Find Full Text PDF

Transforming growth factor-beta (TGF-β) is critical for cell proliferation and differentiation in dental pulp. Here, we show the dynamic mechanisms of TGF-β in porcine dental pulp, odontoblasts and dentin. The mRNA of latent TGF-β1 and TGF-β3 is predominantly expressed in odontoblasts, whereas the mRNA expression level of latent TGF-β2 is high in dental pulp.

View Article and Find Full Text PDF