Human embryonic stem cells (hESCs) have the potential for use in regenerative medicine and in the field of basic research. Therefore, effective cryopreservation and storage of hESCs are important for preservation of newly established cell line for various purposes. Despite poor survival and slow recovery after thawing, the conventional slow freezing method is most commonly used for cryopreservation of hESCs due to its simplicity and ease of use for freezing a large number of hESCs appropriate to clinical applications. Here we controlled the clump size (Group Ⅰ; 400～450 ㎛, Group Ⅱ; 800～900 ㎛, and Group Ⅲ; 1500～1700 ㎛) of hESCs at 5 days after plating using a glass pipette during cryopreservation in order to obtain a larger amount of hESCs after thawing. Attachment rates differed significantly (P<0.05) in each of the three groups and the average of attachment rate of GroupⅡ was highest in SNUhES4 and H1. In particular, the attachment rate of Group Ⅱ in SNUhES3 showed a significant improvement with ROCK inhibitor Y-27632. These results indicate that clump size and cell-cell adhesions of GroupⅡ are appropriate for cryopreservation compared to the Group Ⅰ and Group Ⅲ. This method increased cell viability and reduced the recovery time leading to various experiments, and therefore has an advantage for use with hESCs like newly established in particular. We demonstrated that use of this effective cryopreservation method with control of the clump size of hESCs can effectively improve the attachment rate and survival of post-thaw hESCs with and without Y-27632.

Health beneficial properties of soybean [Glycine max (L.) Merr.] isoflavones are well known. The objectives of this study were to determine and compare the isoflavone composition and concentrations of soybean varieties grown in different cultivated regions of Vietnam (i.e., upland and lowland). Total and individual isoflavone composition and concentrations were determined by high-performance liquid chromatography (HPLC). Total isoflavone concentrations varied from 1153 to 6604~mug~;g-1 and averaging 3354~mug~;g-1 across environments and varieties. In the lowland region, the highest total isoflavones concentration was observed in M103 cultivar (5653~mug~;g-1 ) and the lowest in VX9-3 (1153~mug~;g-1 ), whereas in the upland region the highest and lowest concentrations were in M103 (6604~mug~;g-1 ) and DT93 (1938~mug~;g-1 ), respectively. Across varieties, average total isoflavones concentration was higher in the upland than lowland region (3728 vs. 2980~mug~;g-1 ). The malonylglucosides and acetylglucosides concentrations in upland soybean varieties were higher than those from the lowland region. Despite the presence of Genotype (G) x Environment (E) interactions, varieties with consistently high (M103) and low (VX9-3, DT93) isoflavone concentrations across environments were identified. This is the first report of isoflavones in Vietnamese soybean varieties, revealing large variation in isoflavones concentration and profile among different varieties and cultivated regions. Results will be useful in selecting high-isoflavones soybean varieties for growth in tropical regions.