Central Institute for Experimental Animals CIEA

Kawasaki, Japan

Central Institute for Experimental Animals CIEA

Kawasaki, Japan
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Yoshida K.,Keio University | Mimura Y.,Keio University | Ishihara R.,Keio University | Nishida H.,Keio University | And 8 more authors.
Journal of Neuroscience Methods | Year: 2016

Background Functional magnetic resonance imaging (fMRI) in mice is typically performed under anesthesia due to difficulties in holding the head of awake mice stably with a conventional three-point fixation method that uses a tooth-bar and earplugs. Although some studies have succeeded in fMRI in awake mice by attaching a head-post on the skull, this cannot be applied to fMRI using a high signal-to-noise ratio (SNR) cryogenic MRI-detector, CryoProbe, because it covers the head of a mouse closely. New method We developed head-fixation implements for awake mice that are applicable to fMRI using CryoProbe. Results A head-bar was surgically attached to the skull of a mouse that was then habituated to a mock fMRI-environment, two hours/day for eight days with physiological examinations of body-weight, fecal weight, electromyogram (EMG), and electrocardiogram. EMG power decreased with just one day of habituation, whereas heart rate decreased after at least seven days of habituation. Estimated head motions of awake mice during fMRI were significantly smaller than a voxel size. Unexpectedly, temporal SNR of fMRI signals for awake mice was higher than that for anesthetized mice held by a conventional method. Functional connectivity in the brain of both anesthetized and awake mice showed bilateral and unilateral networks. Comparison with existing method(s) fMRI using CryoProbe had been performed on anesthetized mice previously. Our method does not use anesthetics during habituation or fMRI. Conclusion Our method would be beneficial for translational research using fMRI in mice and humans because human fMRI is typically performed without anesthetics. © 2016


Matsuyama M.,Tokai University | Matsuyama M.,Central Institute for Experimental Animals CIEA | Wakui M.,Central Institute for Experimental Animals CIEA | Wakui M.,Keio University | And 20 more authors.
Oncology Letters | Year: 2010

Liver metastases of colorectal cancers significantly affect the prognoses of patients. To further understand the biological aspects of the metastatic phenotypes, we established the highly liver-metastatic human colorectal cancer cell subline SW48LM2. The subline was established through the serial intrasplenic transfer of cells derived from poor but visible hepatic tumor foci formed by parental SW48 cells and transferred to NOD/SCID/IL-2Rγcnull mice. The growth, both under monolayer culture conditions and during the formation of subcutaneous tumors, was similar between the two cell lines, although there were morphological differences in the in vitro spheroid formation. Of 41 molecules reportedly associated positively or negatively with tumor progression, four were overexpressed and four were underexpressed in SW48LM2 cells. Notably, this liver-metastatic cell subline exhibited a strongly reduced expression of the ecto-5'-nucleotidase CD73 as well as an altered metabolism of purine nucleotides. Previous studies showed a positive correlation between CD73 expression and metastatic cancer phenotypes. A reduced CD73 expression in tumor cells, however, may contribute to obtaining insight into the mechanisms of liver metastases.

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