Compact pnCCD-based X-ray camera with high spatial and energy resolution: a color X-ray camera.

For many applications there is a requirement for nondestructive analytical investigation of the elemental distribution in a sample. With the improvement of X-ray optics and spectroscopic X-ray imagers, full field X-ray fluorescence (FF-XRF) methods are feasible. A new device for high-resolution X-ray imaging, an energy and spatial resolving X-ray camera, is presented. The basic idea behind this so-called "color X-ray camera" (CXC) is to combine an energy dispersive array detector for X-rays, in this case a pnCCD, with polycapillary optics. Imaging is achieved using multiframe recording of the energy and the point of impact of single photons. The camera was tested using a laboratory 30 µm microfocus X-ray tube and synchrotron radiation from BESSY II at the BAMline facility. These experiments demonstrate the suitability of the camera for X-ray fluorescence analytics. The camera simultaneously records 69,696 spectra with an energy resolution of 152 eV for manganese K(α) with a spatial resolution of 50 µm over an imaging area of 12.7 × 12.7 mm(2). It is sensitive to photons in the energy region between 3 and 40 keV, limited by a 50 µm beryllium window, and the sensitive thickness of 450 µm of the chip. Online preview of the sample is possible as the software updates the sums of the counts for certain energy channel ranges during the measurement and displays 2-D false-color maps as well as spectra of selected regions. The complete data cube of 264 × 264 spectra is saved for further qualitative and quantitative processing.

Protein expression in the tissues of the cardiovascular system of the rat under selenium deficiency and adequate conditions.

We investigate the effects of selenium in tissues of the cardiovascular system. In order to examine the expression of the heart and aorta proteins (part of them) in the homogenate of selenium-deficient (Se(-)) and selenium control rats (Se(+)), two-dimensional electrophoresis was used by means of giga gels (30 x 35 cm). After electrophoresis, the protein expression pattern of the (Se(-)) gel and (Se(+)) gel was compared. The evaluation of the protein difference was implemented by means of a computer program suitable for the analysis of protein separated by the two-dimensional electrophoresis. In this way more than 2000 proteins a gel (heart) were detected and more than 1900 protein spots were detected in the aorta fraction. Ten significant differences were found between the gel of (Se(+)) and (Se(-)) heart homogenate of the rat and more than 15 significant differences between the gel of (Se(+)) and (Se(-)) of the aorta. By means of MALDI-MS-ESI-MS some of these proteins with different expression levels were not determined until now. Of those, three proteins were detected as the alpha myosin heavy chain (alpha-MHC), myosin light chain 1 and 2 (MLC 1 and 2), and the mitochondrial enzyme creatinine kinase. First results suggest that selenium deficiency affects myocardial energy metabolism and contractile proteins.

Metal-containing proteins in the apoptosis and redox processes in the rat prostate and human prostate cells.

Several trace elements, such as Se, Cu, Mn, and Zn are bound to proteins (metallo- and metalloidproteins) in the prostate gland. Currently, it is known that some of those elements play a role in the apoptosis of different cells and redox processes. For the detection of such proteins, analytical and biochemical procedures were combined. SEC and ICP-MS were used to detect some trace elements, which are bound to proteins in the prostate cytosol and/or in the human prostate cell lines. Several antibodies against specific proteins were tested. By means of some of these antibodies several trace element-containing proteins, such as selenoproteins and Cu- and Cu-Zn-proteins, could be identified in the prostate. In addition, the localization of such metal- and metalloid-containing proteins in the micro organelles and cytosol of the prostate indicates specific functions of these proteins because, as it is known, such metal- and metalloid proteins play a role in the apoptosis and especially in the redox processes.

Detection and characterization of membrane-bound selenoproteins in the kidney of the rat.

The essential trace element selenium is of fundamental importance to human biology. Information on the membrane-bound selenoproteins was obtained by labeling of rats in vivo with (75)Se-selenite, subcellular fractionation of the tissue homogenates, separation of the proteins by SDS-PAGE, two-dimensional electrophoresis, and selenium detection by autoradiography. In this way, in addition to already known membrane-bound selenoproteins three novel selenoproteins in the molecular mass range of 38-40, 18, and 12-13 kDa were detected in the microsomal membranes.