A new mouse model for renal lesions produced by intravenous injection of diphtheria toxin A-chain expression plasmid

BACKGROUND: Various animal models of renal failure have been produced and used to investigate mechanisms underlying renal disease and develop therapeutic drugs. Most methods available to produce such models appear to involve subtotal nephrectomy or intravenous administration of antibodies raised against basement membrane of glomeruli. In this study, we developed a novel method to produce mouse models of renal failure by intravenous injection of a plasmid carrying a toxic gene such as diphtheria toxin A-chain (DT-A) gene. DT-A is known to kill cells by inhibiting protein synthesis. METHODS: An expression plasmid carrying the cytomegalovirus enhancer/chicken β-actin promoter linked to a DT-A gene was mixed with lipid (FuGENE™6) and the resulting complexes were intravenously injected into adult male B6C3F1 mice every day for up to 6 days. After final injection, the kidneys of these mice were sampled on day 4 and weeks 3 and 5. RESULTS: H-E staining of the kidney specimens sampled on day 4 revealed remarkable alterations in glomerular compartments, as exemplified by mesangial cell proliferation and formation of extensive deposits in glomerular basement membrane. At weeks 3 and 5, gradual recovery of these tissues was observed. These mice exhibited proteinuria and disease resembling sub-acute glomerulonephritis. CONCLUSIONS: Repeated intravenous injections of DT-A expression plasmid DNA/lipid complex caused temporary abnormalities mainly in glomeruli of mouse kidney. The disease in these mice resembles sub-acute glomerulonephritis. These DT-A gene-incorporated mice will be useful as animal models in the fields of nephrology and regenerative medicine

Comparative proteomics using 2-D gel electrophoresis and mass spectrometry as tools to dissect stimulons and regulons in bacteria with sequenced or partially sequenced genomes

We propose two-dimensional gel electrophoresis (2-DE) and mass spectrometry to define the protein components of regulons and stimulons in bacteria, including those organisms where genome sequencing is still in progress. The basic 2-DE protocol allows high resolution and reproducibility and enables the direct comparison of hundreds or even thousands of proteins simultaneously. To identify proteins that comprise stimulons and regulons, peptide mass fingerprint (PMF) with matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI-TOF-MS) analysis is the first option and, if results from this tool are insufficient, complementary data obtained with electrospray ionization tandem-MS (ESI-MS/MS) may permit successful protein identification. ESI-MS/MS and MALDI-TOF-MS provide complementary data sets, and so a more comprehensive coverage of a proteome can be obtained using both techniques with the same sample, especially when few sequenced proteins of a particular organism exist or genome sequencing is still in progress

Effect of strain path on evolution of deformation bands during ECAP of pure aluminum

The influence of strain path during equal channel angular pressing (ECAP) has been evaluated in pure aluminum by orientation imaging microscopy (OIM) and transmission electron microscopy (TEM). The material was examined after four pressing operations by route BC in a 90◦ die, or eight pressing operations by route BC in a 135◦ die. The von Mises equivalent strains were essentially the same for these two ECAP procedures. The microtexture data indicate that the distortion during ECAP corresponds to a simple shear in a direction approximately parallel to die-channel exit and on a plane perpendicular to the flow plane. For both procedures, the OIM data reveal prominent meso-scale band-like features. Lattice orientations in each band correspond to a texture orientation but the particular combinations of orientations depend upon ECAP die angle.High-angle boundaries in the structure correspond to interfaces between the bands

Influence of ECAP processing parameters on texture and microstructure of commercially pure aluminum

The development of shear textures and band-like features in the microstructure of commercially pure (CP) aluminum have been studied as a function of backpressure and die relief angle during equal-channel angular pressing (ECAP) through a die with a 90◦ die channel angle. Microtexture data were acquired by orientation imaging microscopy (OIM) following one pass and four repetitive passes by route A. In a 90◦ die with zero relief angle, the microtexture data indicate that ECAP involves simple shear on a shear plane and in a shear direction that are rotated away from the plane of the die channel intersection toward the die exit channel. This rotation reflects the spreading of shear deformation through a fan-shaped region around the plane of the die channel intersection. The superposition of backpressure suppresses this spreading and the texture data indicate that deformation is confined to the plane of the die channel intersection, while the introduction of a relief angle at the outer corner of the die channel intersection promotes spreading and leads to further rotation of the shear plane and shear direction toward the axis of the die exit channel. Splitting of shear texture components is observed after the initial ECAP pass. Such splitting appears in the microstructure as band-like features separated by sub-grains. Band-like features became apparent in the microstructure after the initial pass and persisted through four ECAP passes by route A; these features become more prominent with increasing die relief angle

Microtexture and microstructure evolution during processing of pure aluminum by repetitive EACP

Microtexture and microstructure evolution during repetitive equal-channel angular pressing (ECAP) of pure aluminum through a 90◦ die was evaluated by orientation imaging microscopy (OIM) and transmission electron microscopy (TEM). Billet distortion appears to conform to the idealized ECAP model. After the initial pass, the textures were inhomogeneous but one or more shear-texture components and long-range lattice rotations were apparent. Following repetitive ECAP, the textures became more homogeneous but still included either two or three distinct shear-texture orientations. The OIM and TEM data revealed meso-scale deformation bands that were inclined at about 26◦ to the axis of the as-pressed samples and that involved alternation of lattice orientations between distinct shear-texture orientations. The band interfaces were of high disorientation (40–62.8◦) and were distinct boundaries in TEM. The evolution of the band structures during repetitive ECAP accounts for an increasing population of high-angle boundaries in repetitively processed materials