A hard-x-ray telescope is successfully produced for balloon observations by making use of depth-graded multilayers, or so-called supermirrors, with platinum-carbon (Pt/C) layer pairs. It consists of four quadrant units assembled in an optical configuration with a diameter of 40 cm and a focal length of 8 m. Each quadrant is made of 510 pieces of coaxially and confocally aligned supermirrors that significantly enhance the sensitivity in an energy range of 20-40 keV. The configuration of the telescope is similar to the x-ray telescope onboard Astro-E, but with a longer focal length. The reflectivity of supermirrors is of the order of 40% in the energy range concerned at a grazing angle of 0.2 deg. The effective area of a fully assembled telescope is 50 cm2 at 30 keV. The angular resolution is 2.37 arc min at half-power diameter 8.0 keV. The field of view is 12.6 arc min in the hard-x-ray region, depending somewhat on x-ray energies. We discuss these characteristics, taking into account the figure errors of reflectors and their optical alignment in the telescope assembly. This hard-x-ray telescope is unanimously afforded in the International Focusing Optics Collaboration for muCrab Sensitivity balloon experiment.
The migration inhibitory factor-related proteins (MRPs) MRP-8 and MRP-14 were detected in differentiated human leukemia cell lines (THP-1 and HL-60) by immunocytochemical analysis. They were induced and colocalized in the cytoplasm and in lesser amounts in the nucleus when THP-1 and HL-60 cells were induced to differentiate by 1alpha,25-dihydroxyvitamin D3 or retinoic acid. In a search for a protein capable of binding MRPs, both MRPs were individually produced in insect cells (Sf21) infected with recombinant baculovirus. The purified recombinant MRPs were electrophoretically and antigenically indistinguishable from the native proteins, and their ability to form the MRP8/14 complex was retained. The presence of MRP binding sites was investigated by a binding assay using recombinant MRPs and specific monoclonal antibodies. MRP binding sites were detected on the cell membrane of the human leukemia cell lines THP-1, Raji, and MOLT-4. HL-60 cells treated with 1alpha, 25-dihydroxyvitamin D3 did not express MRP binding sites on the cell membrane, but a high level of MRPs accumulated in the cells. The occurrence of MRP binding sites on the cell surface of leukemia cell lines of monocyte and lymphocyte origin suggests that MRPs, released from neutrophils under certain conditions, may contribute to the activation and recruitment of effector cells to inflammatory lesions.
Various antitumor drugs which target tumor cells in the S‐phase of the cell cycle induce apoptosis in HL‐60 cells. The present study shows that apoptosis is inducible in HL‐60 cells by continuous exposure to bromodeoxyuridine (BrdU), an S‐phase specific reagent and a thymidine analogue. The localization of BrdU in the apoptotic cells was visualized with immunogold particles using an antl‐BrdU monoclonal antibody. After 3 days of treatment with 20 μM BrdU, cells ceased to grow and their viability was significantly decreased. Morphologically, nuclear segmentation and cytoplasmic maturation were observed in many viable cells, and the dead cells showed typical features of apoptosis. The nuclear DNA of apoptotic cells was visualized by the immunocytochemical detection of BrdU with post‐embedding immunogold staining. The condensed chromatin of the apoptotic cells was highly labeled with immunogold particles, while the nucleolus was sparsely labeled. The chromatin could be traced with BrdU‐immunocytochemistry even after disappearance of the nuclear envelope. These results indicated that apoptosis in HL‐60 cells was induced by incorporation of BrdU into DNA of the S‐phase cells. Using BrdU‐immunocytochemistry, the localization of nuclear DNA in apoptotic cells was visualized and the changes of nuclear structures were followed during the progression of apoptosis.
Ultrastructural changes of liver peroxisomes of Wistar male rats after administration and withdrawal of bezafibrate were studied by morphometric and cytochemical methods. The volume of the liver, number and size of peroxisomes were significantly increased by the administration of bezafibrate for 2 weeks. All of these changes returned almost to normal within 2 weeks of bezafibrate withdrawal. Bundles of tubules and filaments in the matrix appeared only after the withdrawal of bezafibrate, the finding which has not been reported previously. At l week of bezafibrate withdrawal, catalase activity appeared very heterogeneous in large-spherical peroxisomes, but not in tubular peroxisomes. These results suggest that morphological changes occurring in the recovery process are significant, similarly as those seen in the proliferation process of peroxisomes.
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