We constructed a laboratory-size three-dimensional water-window x-ray microscope that combines wide-field transmission x-ray microscopy with tomographic reconstruction techniques. It consists of an electron-impact x-ray source emitting oxygen Kα x-rays, Wolter type I grazing incidence mirror optics, and a back-illuminated CCD for x-ray imaging. A spatial resolution limit better than 1.0 line pairs per micrometer was obtained for two-dimensional transmission images, and 1-μm-scale three-dimensional fine structures were resolved.
We developed a compact laser electron source which can be used as an X-ray source for nondestructive diagnosis instead of radio isotopes. High energy electrons were generated by an ultrashort laser pulse focused on a thin tape target. The laser energy was only 15 mJ. Pulse duration and beam diameter of the laser beam were 140 fs and 10 mm, respectively. We got over 1 MeV energetic electrons with this compact laser electron source.
Plasma phenomenon has been demonstrated as a new promising tool in medical field, although little is known about the plasma irradiation effects on tissues in abdominal cavity. Therefore finding the possible marker is the first and the key step to evaluate the events after plasma irradiation and a suitable mouse model is required to validate the plasma effects. We focused on abdominal adhesion formation that is the secondary event after surgery irrespective of the any surgical devices, and is associated with complications such as ileus, abdominal pain or infertility. Firstly we generated a mouse abdominal adhesion model using bipolar forceps. Within 7days, cauterized cecum was demonstrated to recruit the epididymal adipose tissue (EAT), which connected tissues abnormally and infiltrated inflammatory cells into EAT were observed by microscopic examination. We also identified some inflammatory proteins released into peritoneal cavity by proteomics of ascites after cauterization. Moreover, we measured serum cytokines level and determined that adhesion could be evaluated as a result of the alteration of pro-inflammatory and anti-inflammatory cytokines. Now we are pursuing to assess the plasma irradiation effects using those inflammatory proteins and cytokines as an appropriate marker.
Ultra-short gamma ray pulses of the picosecond and femtosecond range can be generated using laser Compton scattering with 90-degree collisions at the UVSOR-II electron storage ring. Measurement techniques for a gamma ray pulse width in the sub-picosecond to picosecond range are being developed. As the first stage of the development, we tested a pulse width measuring method for the gamma ray pulses with pulse width of 4.8 ps (FWHM) consisted of a multi-pixel photon counter (MPPC) and a digital oscilloscope. The time resolution of the MPPC was measured as 477 ps (FWHM) by using a single photon counting technique. It was indicated the shortest pulse width that the MPPC could evaluate was 82 ps under ideal conditions. However, the measured gamma ray pulse width was 540 ps. The main reason for the large discrepancy is considered to be the noise of the trigger signal synchronized with the gamma rays. The measured gamma ray pulse width can be lowered by increasing the signal-to-noise ratio of the trigger signal and using a fast photodetector, a microchannel plate photomultiplier tube (MCP-PMT) with a time resolution of few tens of picoseconds. As the next stage, we will develop a pulse width measurement technique in the femtosecond range by using a pump-probe technique with a femtosecond laser and ultra-short gamma ray pulses.
Podocytes are specialized actin-rich epithelial cells that line the kidney glomerular filtration barrier. The interface between the podocyte and the glomerular basement membrane requires integrins, and defects in either α3 or β1 integrin, or the α3β1 ligand laminin result in nephrotic syndrome in murine models. The large cytoskeletal protein talin1 is not only pivotal for integrin activation, but also directly links integrins to the actin cytoskeleton. Here, we found that mice lacking talin1 specifically in podocytes display severe proteinuria, foot process effacement, and kidney failure. Loss of talin1 in podocytes caused only a modest reduction in β1 integrin activation, podocyte cell adhesion, and cell spreading; however, the actin cytoskeleton of podocytes was profoundly altered by the loss of talin1. Evaluation of murine models of glomerular injury and patients with nephrotic syndrome revealed that calpain-induced talin1 cleavage in podocytes might promote pathogenesis of nephrotic syndrome. Furthermore, pharmacologic inhibition of calpain activity following glomerular injury substantially reduced talin1 cleavage, albuminuria, and foot process effacement. Collectively, these findings indicate that podocyte talin1 is critical for maintaining the integrity of the glomerular filtration barrier and provide insight into the pathogenesis of nephrotic syndrome.
