Biomedical subjects

Yoshifumi Amano

Publications and source records attributed to Yoshifumi Amano.

3 recordsLinked to original sources

PubMed2006

Effect of oxygen on in vitro differentiation of mouse embryonic stem cells.

The monolayer culture of embryonic stem (ES) cells and embryoid body (EB) formation were carried out under various oxygen tensions (i.e., 5% O2, 20% O2, and 40% O2). The ES cells cultured in 5% O2 and 20% O2 exhibited decreased specific alkaline phosphatase (AP) activity with culture time, whereas the ES cells cultured in 40% O2 retained their specific AP activity until culture day 3. The ES cells in 40% O2 maintained an octamer-binding transcription factor 4 (Oct-4; a marker of pluripotent undifferentiated ES cells) gene expression level higher than that at other oxygen tensions. The EB formed in 40% O2 maintained an Oct-4 gene expression level higher than that at other oxygen tensions. The generation of cardiomyocytes and the decline in Oct-4 gene expression level were earliest in the EB formed in 20% O2. It was suggested that the culture condition under a high oxygen tension (40% O2) retards the differentiation of ES cells and a normal oxygen tension (20% O2) allows spontaneous cell differentiation.

Alkaline Phosphatase↗

PubMed2003

Morphology and albumin secretion of adult rat hepatocytes cultured on a hydrophobic porous expanded polytetrafluoroethylene membrane.

Primary culture of rat hepatocytes was performed on a hydrophobic porous expanded polytetrafluoroethylene (ePTFE) membrane incorporated into the base of a culture dish. Two types of ePTFE membranes, a uniaxially expanded type (ePTFE-1) and a biaxially expanded type (ePTFE-2), could be used as the culture surfaces for hepatocytes. The formation of multicellular aggregates was observed in the culture dish when each membrane type was used. A pore size of 1 mum or higher was adequate for cell adhesion and albumin secretion for both membrane types. The activity of albumin secretion in the dish with the ePTFE membrane was markedly higher than that in the polystyrene dish. Spheroidal multicellular aggregates (spheroids) were observed when hepatocytes were cultured on the ePTFE-1 membrane. The ePTFE-1 membrane maintained the albumin secretion activity for a longer period than the non-expanded PTFE film. It was assumed that the cooperative action of membrane structure and oxygen permeability promoted the formation of cell aggregates and increased the albumin secretion activity.

Journal Article↗

PubMed2003

A simple method for forming embryoid body from mouse embryonic stem cells.

We proposed a simple method for forming an embryoid body (EB) from mouse embryonic stem (ES) cells using a polypropylene 1.5-ml conical tube with a screw cap. An ES cell suspension containing 2 x 10(4) cells was incubated in a conical tube. After 5 d of incubation, a single EB of 440 microm average diameter was formed in the conical tube. The formation efficiency of EB, which is the ratio of the number of tubes showing EB formation to the number of tubes seeded with ES cells, was greater than 99% in the conical tube, while it was approximately 60% in a hanging drop culture. The 5-day-old EB formed by the conical tube method had a sufficient differentiation ability. The beating of the cardiac muscle was microscopically observed in the populations derived from the 5-day-old EB.

Journal Article↗