Biomedical subjects

Shizue Hayashi

Publications and source records attributed to Shizue Hayashi.

3 recordsLinked to original sources

PubMed2005

Regulation of neurite outgrowth by intermittent irradiation of visible light.

The effect of neurite outgrowth of PC12 cells on collagen-coated glass plates under intermittent light irradiation at 525 nm and 0.4 mW/cm2 of intensity was investigated. Neurite outgrowth of PC12 cells was significantly suppressed when PC12 cells were cultivated under intermittent light irradiation with a total irradiation time of more than 2 min/h. No temperature increase was observed in the culture medium under either continuous or intermittent light irradiation. Therefore, suppression of neurite outgrowth under light irradiation was not due to the increase of temperature in the culture medium, but rather the effect of light on the PC12 cells, especially the signal transmittance of light to PC12 cells. The light irradiation interval also affected the neurite outgrowth of PC12 cells when the total irradiation time was constant. A high extension ratio of neurite outgrowth was observed under a long time interval of nonirradiation between light irradiations (1 min of irradiation every hour) as compared with frequent light irradiation intervals (5 s of irradiation every 5 min) with the same total irradiation period per hour. The neurite outgrowth ratio was thought to be dependent on the light intensity, the total time of light irradiation in the intermittent light irradiation, and the interval of light irradiation in the intermittent light irradiation.

Animals↗

PubMed2004

Analytical and computational techniques for exogenous depolymerization of xenobiotic polymers.

We analyze a mathematical model for exogenous depolymerization of xenobiotic polymers. We derive a sufficient condition for the solvability of its inverse problem to determine degradation rates. We also introduce a numerical technique to solve the inverse problem with an example to show how our numerical technique is applied to gel permeation chromatography data of polyethylene wax obtained before and after three-week cultivation of a fungus Aspergillus sp. AK-3. In addition, we present a numerical result which we obtained by applying the degradation rate based on the three week cultivation to simulate the transition of the weight distribution after cultivation of the fungus for five weeks.

Algorithms↗

PubMedDate not supplied

Temperature-dependent cell detachment on Pluronic gels.

Cell culture on gels made of poly(ethylene oxide) and poly(propylene oxide) (Pluronic), which has a lower critical solution temperature around 30 degrees C, could be performed for 48 h. However, the Pluronic gels were highly hydrophilic and tended to dissolve in the culture medium. We achieved temperature-dependent detachment of cells from Pluronic gels containing or lacking extracellular matrix (ECM) by cooling the gels to 4 degrees C. Using normal human umbilical vein endothelial cells (HUVECs) grown on and released from Pluronic gels lacking ECM, we further found that the expression ratio of the surface markers CD34 and CD105 was twofold higher than for cells grown on polystyrene and removed with trypsin. In addition, the expression ratios for CD34 and CD105 on HUVECs cultivated on the Pluronic gels containing higher concentrations of ECM were lower, which may be due to ECM coating of the cell surface and, thus, interference with antibody binding. In summary, temperature-dependent detachment of cells from Pluronic gels allows the isolation of cells under mild conditions. This can be a powerful tool for surface marker analysis by flow cytometry.

Antigens, CD↗