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Dive into the research topics where Hiroaki Kii is active.

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Featured researches published by Hiroaki Kii.


Scientific Reports | 2016

Parametric analysis of colony morphology of non-labelled live human pluripotent stem cells for cell quality control

Ryuji Kato; Megumi Matsumoto; Hiroto Sasaki; Risako Joto; Mai Okada; Yurika Ikeda; Kei Kanie; Mika Suga; Masaki Kinehara; Kana Yanagihara; Yujung Liu; Kozue Uchio-Yamada; Takayuki Fukuda; Hiroaki Kii; Takayuki Uozumi; Hiroyuki Honda; Yasujiro Kiyota; Miho K. Furue

Given the difficulties inherent in maintaining human pluripotent stem cells (hPSCs) in a healthy state, hPSCs should be routinely characterized using several established standard criteria during expansion for research or therapeutic purposes. hPSC colony morphology is typically considered an important criterion, but it is not evaluated quantitatively. Thus, we designed an unbiased method to evaluate hPSC colony morphology. This method involves a combination of automated non-labelled live-cell imaging and the implementation of morphological colony analysis algorithms with multiple parameters. To validate the utility of the quantitative evaluation method, a parent cell line exhibiting typical embryonic stem cell (ESC)-like morphology and an aberrant hPSC subclone demonstrating unusual colony morphology were used as models. According to statistical colony classification based on morphological parameters, colonies containing readily discernible areas of differentiation constituted a major classification cluster and were distinguishable from typical ESC-like colonies; similar results were obtained via classification based on global gene expression profiles. Thus, the morphological features of hPSC colonies are closely associated with cellular characteristics. Our quantitative evaluation method provides a biological definition of ‘hPSC colony morphology’, permits the non-invasive monitoring of hPSC conditions and is particularly useful for detecting variations in hPSC heterogeneity.


Stem Cells Translational Medicine | 2015

Development of a Monitoring Method for Nonlabeled Human Pluripotent Stem Cell Growth by Time-Lapse Image Analysis

Mika Suga; Hiroaki Kii; Keiichi Niikura; Yasujiro Kiyota; Miho K. Furue

Cell growth is an important criterion for determining healthy cell conditions. When somatic cells or cancer cells are dissociated into single cells for passaging, the cell numbers can be counted at each passage, providing information on cell growth as an indicator of the health conditions of these cells. In the case of human pluripotent stem cells (hPSCs), because the cells are usually dissociated into cell clumps of ∼50–100 cells for passaging, cell counting is time‐consuming. In the present study, using a time‐lapse imaging system, we developed a method to determine the growth of hPSCs from nonlabeled live cell phase‐contrast images without damaging these cells. Next, the hPSC colony areas and number of nuclei were determined and used to derive equations to calculate the cell number in hPSC colonies, which were assessed on time‐lapse images acquired using a culture observation system. The relationships between the colony areas and nuclei numbers were linear, although the equation coefficients were dependent on the cell line used, colony size, colony morphology, and culture conditions. When the culture conditions became improper, the change in cell growth conditions could be detected by analysis of the phase‐contrast images. This method provided real‐time information on colony growth and cell growth rates without using treatments that can damage cells and could be useful for basic research on hPSCs and cell processing for hPSC‐based therapy.


Regenerative Therapy | 2017

Visualization of morphological categories of colonies for monitoring of effect on induced pluripotent stem cell culture status

Risako Nagasaka; Megumi Matsumoto; Mai Okada; Hiroto Sasaki; Kei Kanie; Hiroaki Kii; Takayuki Uozumi; Yasujiro Kiyota; Hiroyuki Honda; Ryuji Kato

From the recent advances, there are growing expectations toward the mass production of induced pluripotent stem cells (iPSCs) for varieties of applications. For such type of industrial cell manufacturing, the technology which can stabilize the production efficiency is strongly required. Since the present iPSC culture is covered by delicate manual operations, there are still quality differences in produced cells from same culture protocols. To monitor the culture process of iPSCs with the quantified data to evaluate the culture status, we here introduce image-based visualization method of morphological diversity of iPSC colonies. We have set three types of experiments to evaluate the influential factors in iPSC culture technique that may disturb the undifferentiation status of iPSC colonies: (Exp. 1) technical differences in passage skills, (Exp. 2) technical differences in feeder cell preparation, and (Exp. 3) technical differences in maintenance skills (medium exchange frequency with the combination of manual removal of morphologically irregular colonies). By measuring the all existing colonies from real-time microscopic images, the heterogenous change of colony morphologies in the culture vessel was visualized. By such visualization with morphologically categorized Manhattan chart, the difference between technical skills could be compared for evaluating appropriate cell processing.


The International Journal of Developmental Biology | 2018

A morphology-based assay platform for neuroepithelial-like cells differentiated from human pluripotent stem cells

Mika Suga; Hiroaki Kii; Naoko Ueda; Yujung Liu; Takako Nakano; Tomoro Dan; Takayuki Uozumi; Yasujiro Kiyota; Miho K. Furue

Cell morphology is recognized as an important hallmark of neural cells. During the differentiation of human pluripotent stem cells (hPSCs) into neural cells, cell morphology changes dynamically. Therefore, characterization of the morphology of cells during this period is important to improve our understanding of the differentiation and development of neural cells. General methods for the directed induction of hPSCs include the steps of multi-cellular aggregation or high-density cell culture, particularly at the early phase of neural differentiation, and therefore, the morphology of each differentiating cell is difficult to recognize. Here, we have developed a new method for the directed differentiation of neuroepithelial-like cells (NELCs) from hPSCs at a low cell density in an adherent monolayer culture, as well as an image-processing algorithm to evaluate the cell morphology of differentiating NELCs, in order to follow cell morphology during the differentiation of hPSCs into NELCs. Using these methods, the morphological transition of differentiating cells was observed in real time using phase contrast imaging and then quantified. Because cell morphology is also considered an inherent biological marker of neural cells cultured in vitro, this method is potentially useful to study the mechanisms underlying neural cell differentiation.


Journal of Cancer Research and Clinical Oncology | 2016

Cancer cell invasion driven by extracellular matrix remodeling is dependent on the properties of cancer-associated fibroblasts

Shinya Neri; Hiroko Hashimoto; Hiroaki Kii; Hirotada Watanabe; Kenkichi Masutomi; Takeshi Kuwata; Hiroshi Date; Masahiro Tsuboi; Koichi Goto; Atsushi Ochiai; Genichiro Ishii


Archive | 2007

Apparatus for judging cell detachment, method of judging cell detachment and cell culture apparatus

Yasujiro Kiyota; Hiroaki Kii


Archive | 2011

FOCUS CONTROL METHOD AND CULTURE OBSERVATION APPARATUS

Yasujiro Kiyota; Yoichi Wada; Hiroaki Kii


Archive | 2010

FOCUS CONTROL DEVICE, AND INCUBATION AND OBSERVATION DEVICE

Yasujiro Kiyota; Yoichi Wada; Hiroaki Kii


Cancer Letters | 2017

Fibroblast-led cancer cell invasion is activated by epithelial–mesenchymal transition through platelet-derived growth factor BB secretion of lung adenocarcinoma

Shinya Neri; Tomoyuki Miyashita; Hiroko Hashimoto; Yoshitaka Suda; Masayuki Ishibashi; Hiroaki Kii; Hirotada Watanabe; Takeshi Kuwata; Masahiro Tsuboi; Koichi Goto; Toshi Menju; Makoto Sonobe; Hiroshi Date; Atsushi Ochiai; Genichiro Ishii


Archive | 2014

判定装置、観察システム、観察方法、そのプログラム、細胞の製造方法、および細胞

泰次郎 清田; Yasujiro Kiyota; 宏昭 紀伊; Hiroaki Kii; 美保 古江; Miho Furue; 三佳 菅; Mika Suga

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