The effects of R-75,317 on antiglomerular basement membrane glomerulonephritis in rats

Platelet-activating factor (PAF) is a potent inflammatory mediator which is released by various inflammatory cells and produced by certain tissues, including the kidney. PAF has been shown to increase glomerular permeability to protein and to decrease glomerular filtration rate (GFR) by contracting mesangium. On the basis of these observations, it has been suspected that PAF may play a role as mediator of glomerular damage in glomerular nephritis. To examine this possibility, we studied the effects of a specific PAF antagonist, R-75,317, on the development of an experimental model of anti-glomerular basement membrane (anti-GBM) glomerulonephritis. Glomerulonephritis was initiated by injecting rabbit anti-rat GBM serum into rats. Proteinuria gradually developed after serum injection, plateaued at week 2, and remained at the high level of week 2 throughout the experimental period (6 wk). Chronic treatment with R-75,317 (10 mg/kg/day i.p.) tended to delay the onset of proteinuria and significantly accelerated the recovery phase. Creatinine clearance (Ccr) fell to 40% at week 3. R-75,317 treatment completely prevented this decline of Ccr. Histological changes in this model (glomerular hypertrophy, proliferation of mesangial matrix and interstitial fibrosis) were also ameliorated by the R-75,317 treatment. The results suggest that PAF may play a role in the development of glomerulonephritis and that PAF antagonists could be used in the treatment of human renal disease. Based on a paper presented at the Third International Conference on Platelet-Activating Factor and Structurally Related Alkyl Ether Lipids, May 1989.     

Mutational analysis of structure--activity relationships in human tumor necrosis factor-alpha

To determine the region of human tumor necrosis factor-alpha(TNF-), essential for cytotoxic activity against mouse L-M cells,single amino-acid-substituted TNF- mutant proteins (muteins)were produced in Escherichia coli by protein engineering techniques.An expression plasmid for TNF- was mutagenized by passage throughan E.coli mutD5 mutator strain and by oligonucleotide-directedmutagenesis. Approximately 100 single amino-acid-substitutedTNF- muteins were produced and assayed for cytotoxic activity.The cytotoxic activities of purified TNF- muteins, e.g. TNF-31T,-32Y, -82D, -85H, -115L, -141Y, -144K and -146E, were < 1%of that of parent TNF-. These results indicate that the integrityof at least four distinct regions of the TNF- molecule is requiredfor full biological activity. These regions are designated asfollows: region I, from position 30 to 32; region II, from position82 to 89; region III, from position 115 to 117; region FV, fromposition 141 to 146. In addition, TNF-141Y could not completelycompete with parent TNF- for binding to the receptor. This demonstratesthat region IV, and at least aspartk acid at position 141, mustbe involved in the TNF receptor binding site.     

Polygon visibility ordering via Voronoi diagrams

Visibility determination is one of the oldest problems in computer graphics. The visibility, in terms of back-to-front polygon visibility ordering, is determined by updating a priority list as the viewpoint moves. A new list-priority algorithm, utilizing a property of Voronoi diagrams, is proposed in this paper. The operation is in two phases. First, in a pre-processing phase the scene is divided into Voronoi cells. A sub-list associated with each cell contains references to those polygons that intersect with it. The polygons are assigned a fixed set of view-independent priority orders within the cluster. Last, an interactive phase sorts the clusters according to the depth value of each Voronoi site. The most time-consuming work is performed during the pre-processing phase that only has to be executed once for the scene. Since all the polygons in a cell are pre-computed to obtain the fixed priority order within the cluster, a relatively simple task is left in the interactive phase, which is only to sort the clusters repeatedly when the viewpoint is changed. This method contains performance benefits that make it better shaped than previous BSP based methods.     

Olympic Technologies

The Olympic Games bring tremendous impacts to host cities, yet little attention has been paid to the variety and novelty in urban technologies that are introduced through the mega-event vehicle. This paper argues that urban transformation associated with the Olympic Games increasingly spans the technological sphere. As a path-breaker the Olympic bid of Tokyo foreshadows a technological revolution that will make the capital of Japan the most advanced urban technology metropolis in the world. This is significant, as this pioneer for the city of the future may yield many valuable insights given the rapid implementation and acceleration of technological innovation proceeding into 2020. Consequently, lessons on how this technology may impact our society can be derived.     

Difference in the outdoor performance of bulk and thin-film silicon-based photovoltaic modules

Differences in the outdoor performances of bulk (multi- and single-crystalline Si) and thin-film (amorphous Si(a-Si), a-Si/micro-crystalline Si and a-Si/a-SiGe/a-SiGe) photovoltaic (PV) modules are analyzed. The influence of module temperature and solar spectrum distribution on the PV output is clarified. The PV outputs almost only depend on module temperature in bulk-type Si PV modules while that depend both module temperature and spectrum distribution in thin-film ones. Also, the PV outputs of the bulk-type Si PV modules at most frequent condition at outdoor are lower than that at the standard test condition; in contrast, it was the other way round for thin-film ones.