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911.
Amin AR Attur MG Pillinger M Abramson SB 《Cellular and molecular life sciences : CMLS》1999,56(3-4):305-312
Recent studies have suggested that aspirin and aspirin-like compounds have a variety of actions in addition to their well-studied
ability to inhibit cyclooxygenases. These actions include inhibition of the uncoupling of oxidative phosphorylation, decreases
in adenosine triphosphate stores, increases in extracellular adenosine, downregulation of the expression and activity of inducible
nitric oxide synthetase, inhibition and/or stimulation of various mitogen-activated protein kinase activities and inhibition
of nuclear factor binding κB site (NF-κB) activation. Moreover, aspirin-like compounds have recently been shown to have previously
unappreciated clinical and biological effects, some apparently independent of cyclooxygenase. In this review we discuss the
various mechanisms of action of aspirin-like compounds and their relevance to clinical disease and therapy.
Received 1 February 1999; received after revision 1 April 1999; accepted 7 May 1999 相似文献
912.
A population of ventral neural tube cells has recently been shown to migrate out of the hind brain neural tube via the vagus
nerve and contribute to the developing gastrointestinal tract. Since liver is also innervated by the vagus nerve, we sought
to determine if these cells also migrate into the liver. Ventral neural tube cells in the caudal hindbrain of chick embryos
were tagged with a replication-deficient retroviral vector containing the LacZ gene on embryonic day 2. Embryos were processed
for detection of labeled cells on embryonic day 5 and 11. Labeled cells were seen in the liver on both days and identified
as hepatocytes. Previously, it was believed that all hepatocytes develop from the gut endoderm. Results of the present study
show an additional source for the formation of liver cells.
Received 25 August 1998; received after revision 5 November 1998; accepted 5 November 1998 相似文献
913.
Eukaryotic glycosylation: whim of nature or multipurpose tool? 总被引:13,自引:0,他引:13
Protein and lipid glycosylation is a ubiquitous phenomenon. The task of cataloguing the great structural variety of the glycan part has demanded considerable efforts over decades. This patient endeavor was imperative to discern the inherent rules of glycosylation which cannot affirm assumptions on a purely coincidental nature of this type of protein and lipid modification. These results together with theoretical considerations uncover a salient property of oligosaccharides. In comparison with amino acids and nucleotides, monosaccharides excel in their potential to serve as units of hardware for storing biological information. Thus, the view that glycan chains exclusively affect physiochemical properties of the conjugates is indubitably flawed. This original concept has been decisively jolted by the discovery of endogenous receptors (lectins) for distinct glycan epitopes which are as characteristic as a fingerprint or a signature for a certain protein (class) or cell type. Recent evidence documents that these binding proteins are even endowed with the capacity to select distinct low-energy conformers of the often rather flexible oligosaccharides, granting entry to a new level of regulation of ligand affinity by shifting conformer equilibria. The assessment of the details of this recognition by X-ray crystallography, nuclear magnetic resonance spectroscopy, microcalorimetry and custom-made derivatives is supposed to justify a guarded optimism in satisfying the need for innovative drug design in antiadhesion therapy, for example against viral or bacterial infections and unwanted inflammation. This review presents a survey of the structural aspects of glycosylation and of evidence to poignantly endorse the notion that carrier-attached glycan chains can partake in biological information transfer at the level of cell compartments, cells and organs. 相似文献
914.
915.
Favatier F Jacquier-Sarlin MR Swierczewski E Polla BS 《Cellular and molecular life sciences : CMLS》1999,56(7-8):701-708
A bi-allelic polymorphism found in the regulatory region of the human heat shock (HS) protein (HSP) hsp70-1 gene, which comprises an A-->C transversion, 3 bp upstream of the HS element (HSE), has been associated with extended HLA haplotypes. In view of the chaperoning and protective functions of Hsp70, we investigated whether this hsp70-1 bi-allelic polymorphism could modulate the stress response, which may relate to enhanced resistance or susceptibility to certain diseases. We compared the basal and HS-induced HS factor (HSF)-binding activity of the two polymorphic HSEs, hsp70-1 mRNA accumulation and HSP expression in two human Epstein Barr virus (EBV)-transformed B cell lines typed for hsp70-1 promoter alleles. Our results suggest that hsp70-1 promoter polymorphism does not influence HSF-binding activity, hsp70 mRNA accumulation or synthesis in human EBV-transformed B cell lines. 相似文献
916.
Antigen-specific T cells in autoimmune diseases with a focus on multiple sclerosis and experimental allergic encephalomyelitis 总被引:2,自引:0,他引:2
Although the pathogenesis of autoimmune diseases remains poorly understood, the current view is that autoaggresive antigen-specific T cells play a central role in the cascade of events leading to most autoimmune diseases. A major event in the development of autoimmune diseases is the activation of antigen-specific T cells-how, when and where does this activation take place? This review addresses questions concerning the occurrence of unique autoantigens triggering autoimmune diseases, the factors influencing the balance between self-tolerance and autoaggresive immunity, and the mechanisms by which dendritic cells mediate immunity and tolerance to antigen-specific T cells. Knowledge of how antigen-specific T cells are activated is now being used to develop therapeutic approaches to control autoimmune diseases. We discuss tolerance to antigen-specific T cells and tolerance induction as treatment of T-cell-mediated autoimmune diseases. Therapeutic modalities have been established which selectively target the pathogenic T cells. leaving the remainder of the immune system intact. 相似文献
917.
MAP kinases in plant signal transduction 总被引:10,自引:0,他引:10
Mitogen-activated protein kinase (MAPK) pathways are modules involved in the transduction of extracellular signals to intracellular
targets in all eukaryotes. Distinct MAPK pathways are regulated by different extracellular stimuli and are implicated in a
wide variety of biological processes. In plants there is evidence for MAPKs playing a role in the signaling of abiotic stresses,
pathogens and plant hormones. The large number and divergence of plant MAPKs indicates that this ancient mechanism of bioinformatics
is extensively used in plants and may provide a new molecular handle on old questions. 相似文献
918.
Evolution of bacterial pathogenesis 总被引:6,自引:0,他引:6
Ziebuhr W Ohlsen K Karch H Korhonen T Hacker J 《Cellular and molecular life sciences : CMLS》1999,56(9-10):719-728
The evolution of bacteria is associated with continuous generation of novel genetic variants. The major driving forces in this process are point mutations, genetic rearrangements, and horizontal gene transfer. A large number of human and animal bacterial pathogens have evolved the capacity to produce virulence factors that are directly involved in infection and disease. Additionally, many bacteria express resistance traits against antibiotics. Both virulence factors and resistance determinants are subject to intrastrain genetic and phenotypic variation. They are often encoded on unstable DNA regions. Thus, they can be readily transferred to bacteria of the same species or even to non-related prokaryotes. This review article focuses on the main mechanisms of bacterial microevolution responsible for the rapid emergence of variants with novel virulence and resistance properties. In addition, processes of macroevolution are described with special emphasis on gene transfer and fixation of adaptive mutations in the genome of pathogens. 相似文献
919.
Lucius R Gallinat S Busche S Rosenstiel P Unger T 《Cellular and molecular life sciences : CMLS》1999,56(11-12):1008-1019
Since the discovery 100 years ago by Tigerstedt and Bergman of renin, an acid protease generating angiotensin peptide, numerous discoveries have advanced our understanding of the renin-angiotensin system (RAS). The recent cloning of angiotensin receptors and the availability of specific receptor ligands have allowed characterization of angiotensin-receptor-mediated actions, and an increasing number of studies using biochemical, pharmacological and molecular biological methods has focused on the many different physiological actions of the RAS in various tissues. Angiotensin II, the main effector peptide of the RAS, exerts most of its known actions in blood pressure control and body fluid homeostasis via the AT, receptor. AT, receptors not only play a role in growth control and cell differentiation but have been implicated in apoptosis and tissue regeneration. This review focuses on the extrarenal functions of angiotensin, especially in neuronal cells and the nervous system, and on recent advances in angiotensin receptor research. 相似文献
920.