Biomedical subjects

Satoshi Matsuyama

Publications and source records attributed to Satoshi Matsuyama.

4 recordsLinked to original sources

PubMed2006

Single-shot spectrometry for x-ray free-electron lasers.

An experimental scheme to realize single-shot spectrometry for the diagnostics of x-ray free-electron lasers (XFELs) is presented. The combination of an ultraprecisely figured mirror and a perfect crystal form a simple, high-precision spectrometer that can cover an energy range from a few eV to a hundred eV with high resolution. The application of the spectrometer to determine XFEL pulse widths was investigated theoretically and experimentally. It has been shown that the present system can determine pulse widths from sub-fs to ps in a single shot even for spontaneous radiation. The system can be easily extended to even shorter pulses.

Journal Article↗

PubMed2005

Element array by scanning X-ray fluorescence microscopy after cis-diamminedichloro-platinum(II) treatment.

Minerals are important for cellular functions, such as transcription and enzyme activity, and are also involved in the metabolism of anticancer chemotherapeutic compounds. Profiling of intracellular elements in individual cells could help in understanding the mechanism of drug resistance in tumors and possibly provide a new strategy of anticancer chemotherapy. Using a recently developed technique of scanning X-ray fluorescence microscopy (SXFM), we analyzed intracellular elements after treatment with cis-diamminedichloro-platinum(II) (CDDP), a platinum-based anticancer agent. The images obtained by SXFM (element array) revealed that the average Pt content of CDDP-resistant cells was 2.6 times less than that of sensitive cells, and the zinc content was inversely correlated with the intracellular Pt content. Data suggested that Zn-related detoxification is responsible for resistance to CDDP. Of Zn-related excretion factors, glutathione was highly correlated with the amount of Zn. The combined treatment of CDDP and a Zn(II) chelator resulted in the incorporation of thrice more Pt with the concomitant down-regulation of glutathione. We propose that the generation of an element array by SXFM opens up new avenues in cancer biology and treatment.

Antineoplastic Agents↗

PubMed2004

Image quality improvement in a hard X-ray projection microscope using total reflection mirror optics.

A new figure correction method has been applied in order to fabricate an elliptical mirror to realize a one-dimensionally diverging X-ray beam having high image quality. Mutual relations between figure errors and intensity uniformities of diverging X-ray beams have also been investigated using a wave-optical simulator and indicate that figure errors in relatively short spatial wavelength ranges lead to high-contrast interference fringes. By using a microstitching interferometer and elastic emission machining, figure correction of an elliptical mirror with a lateral resolution close to 0.1 mm was carried out. A one-dimensional diverging X-ray obtained using the fabricated mirror was observed at SPring-8 and evaluated to have a sufficiently flat intensity distribution.

Equipment Design↗

PubMed2002

Enhancement of aromatase gene expression in the mediobasal hypothalamus during anestrus in the beagle bitch.

The relationships among expression of cytochrome p450 aromatase (p450arom) mRNA in the mediobasal hypothalamus (MBH), ovarian aromatase activity, and estrogen secretion were examined throughout the estrous cycle in beagle bitches. Using polymerase chain reaction (PCR) analysis we were able to detect p450arom gene transcripts in the canine MBH. The level of hypothalamic p450arom mRNA increased during the progression of anestrus and declined thereafter. Ovarian p450arom activity, as measured by a (3)H2O assay, were low in anestrus, increased in proestrus, and declined thereafter. Ovarian p450arom activity and plasma estradiol-17beta levels were positively correlated (r=0.77, P<0.05). These results suggest that enhancement of hypothalamic p450arom gene expression is associated with termination of anestrus.

Anestrus↗