Validation of 19F-magnetic resonance determination of myocardial blood volume

Site-specific regeneration of the liver after 70% partial hepatectomy was investigated noninvasively in terms of protein synthesis using PET with L-[methyl-11C]methionine in a living animal. Protein synthesis in rat liver at 24 hr after partial hepatectomy did not occur uniformly in the whole liver but intensely in the middle part of the regenerating organ in comparison with the other parts. The activity was significantly low at the posterior aspect of the liver. On the other hand, site-specific protein synthesis was not observed in normal liver. These results were confirmed by bioimaging analyzer system (BAS) analysis, an invasive method that indicates radioactivities of precise intrahepatic sites. DNA synthesis in regenerating liver was also monitored with [2-14C]thymidine and analyzed by BAS 24 hr after 70% hepatectomy. Site-specific DNA synthesis in regenerating liver corresponding to the protein synthesis was also observed by BAS analysis. These results indicate that liver regeneration occurs intensely in the middle part of the liver and that PET enables noninvasive in vivo biochemical analysis.     

RTK技术在水利水电工程中的应用

通过奎屯河引水改建工程的应用,简要介绍RTK技术的原理作业过程和特点以及在水利水电工程中应用的优越性。     

Traumatic bilateral hypoglossal nerve palsy

A case of bilateral hypoglossal nerve palsy following a road traffic accident is reported. The possible aetiology is discussed.     

British Inflammation Research Association meeting: metalloproteinases and inflammatory diseases, the Fielder Centre, Hatfield, UK, 18 April 1997

Nitric oxide released by macrophages during inflammation reacts with active oxygen to form peroxynitrite. Peroxynitrite nitrates protein and peroxidizes lipids. gamma-Tocopherol traps peroxynitrite and is more effective than alpha-tocopherol in protecting lipids against such peroxidation.     

Novel aspects of the regulation of a cDNA (Arf1) from Chlamydomonas with high sequence identity to animal ADP-ribosylation factor 1

ADP-ribosylation factor (ARF) is a highly conserved, low molecular mass (ca. 21 kDa) GTP-binding protein that has been implicated in vesicle trafficking and signal transduction in yeast and mammalian cells. However, little is known of ARF in plant systems. A putative ARF polypeptide was identified in subcellular fractions of the green alga Chlamydomonas reinhardtii, based on [32P]GTP binding and immunoblot assays. A cDNA clone was isolated from Chlamydomonas (Arf1), which encodes a 20.7 kDa protein with 90% identity to human ARF1. Northern blot analyses showed that levels of Arf1 mRNA are highly regulated during 12 h/12 h light/dark (LD) cycles. A biphasic pattern of expression was observed: a transient peak of Arf1 mRNA occurred at the onset of the light period, which was followed ca. 12 h later by a more prominent peak in the early to mid-dark period. When LD-synchronized cells were shifted to continuous darkness, the dark-specific peak of Arf1 mRNA persisted, indicative of a circadian rhythm. The increase in Arf1 mRNA at the beginning of the light period, however, was shown to be light-dependent, and, moreover, dependent on photosynthesis, since it was prevented by DCMU. We conclude that the biphasic pattern of Arf1 mRNA accumulation during LD cycles is due to regulation by two different factors, light (which requires photosynthesis) and the circadian clock. Thus, these studies identify a novel pattern of expression for a GTP-binding protein gene.