Optical coherence tomography evaluation of the spatiotemporal effects of 3D bone marrow stromal cell culture using a bioreactor.

Performing cell culture in a three-dimensional (3D) environment has various advantages. In cartilage tissue engineering, 3D in vitro cultures utilizing biomaterials and bioreactors can mimic the biological environment. However, the biggest drawback of these 3D culture systems is a limited ability to evaluate 3D cell distribution. Optical coherence tomography (OCT) has recently been used to evaluate 3D cellular morphology and structure in a timely manner. Here, we showed that OCT could be used to visually assess the distribution and the morphology of bone marrow stromal cells under chondrogenic 3D cultivation using alginate gels and rotary culture. In particular, OCT was able to visualize living cells embedded in alginate gels in a non-destructive and 3D manner, as well as quantitatively evaluate cell distribution and spheroid volume. We also found that cells were centralized in rotary culture but peripherally distributed in static culture, while rotary culture enhanced the hypertrophy of marrow stromal cells (MSCs) embedded in alginate gels. Together, our findings demonstrate that OCT can be used to evaluate the spatiotemporal effects of 3D cultivation using alginate gels and rotary culture. Therefore, this method may allow the observation of pre-cultured tissue over time and the optimization of culture conditions for regenerative tissue engineering.

Studies on the Amount of Exposure to Pesticides and Blood Levels of Organophosphorus Pesticides of Farmers Engaging in Fixed Piping Joint Control Works of Disease and Insect Damages to Apples / 日本農村医学会雑誌

In application of organophosphorus pesticides (800-fold dilution of Sumithion and 1500-fold dilution of Diazinon) for the control of disease and insect damages to apples, the amount of exposure to the pesticides, blood levels of the pesticides, and liver function tests of the workers engaging in the application work were observed. Its summary was as follows;<BR>1. The concentration of pesticides inhaled by each worker engaging in the fixed piping joint control was calculated as 0.030±0.042mg/m<SUP>3</SUP> (mean±S. E.).<BR>2 Analysis of the correlation between the inhaled amounts of pesticides and the air velocity disclosed that was a statistically significant positive correlation between the two parameters. Therefore, it will be necessary for the workers engaging in the application of pesticides to amply consider the factor of wind in actual application.<BR>3. Both the serum levels of organophosphorus pesticides and the urinary excretion of p-nitro-m-crezol measured were low.<BR>4. In view of the above-mentioned current amounts of exposure to pesticides, no acute effects of the pesticides were manifest on the liver function tests.<BR>5. However, because the fixed piping joint control system employs the lance application (hand application), the applicator is more liable to be exosed to large amounts of pesticides, the exposure amount being 2.7 times that of speed sprayer (SS) operator.<BR>6. It is not rare that women and the aged engage in the fixed piping joint control; therefore, it is necessary to educate ample care in the protection of workers from exposure to pesticides.