Search results for "Pathway"
showing 10 items of 1685 documents
Identification of conjugation and cleavage products in the thiolytic metabolism of the anticancer drug 4'-(9-acridinylamino)methanesulfon-m-anisidide.
1981
Conjugation and cleavage products in the thiolytic metabolism of the anticancer drug 4′ -(9-acridinyl amino)methanesulfon-m-anisidide were identified primarily by high-pressure liquid chromatography in combination with field desorption mass spectrometry. The spontaneous metabolic pathway of the drug, as related to its susceptibility to nucleophilic attack by endogenous thiols at the 9-carbon atom of the acridine moiety, has been studied. Among the metabolite fraction of 4′-(9-acridinylamino)methanesulfon-m-anisidide excreted in rat bile after administration of a therapeutic dose, a conjugate was identified as the 9-acridinyl thioether of glutathione. This conjugation product and the corresp…
Synthesis of complement by macrophages and modulation of their functions through complement activation.
1983
During the last decade considerable progress has been made to characterize intimate functional links between macrophages, a major cellular component of immunoinflammatory responses, and the complement system representing the major humoral mediator of inflammation. Macrophages of various species and tissue sites have been shown to synthesize and release most of the complement components providing these cells with their own \ldpericellular\rd complement system. Circumstantial evidence for the assembly of both classical and alternative pathway convertases has been adduced. An intricate network of feedback loops involving endogenous and extrinsic factors operates to adjust complement production…
Ability of the T cell-replacing polyanion dextran sulfate to trigger the alternate pathway of complement activation.
1973
Dextran sulfate (DS) consumed C3 in C4 deficient guinea pig serum. This temperature-dependent reaction required Mg++ ions and could therefore be blocked by EDTA. Isolated C3 was not influenced by DS, but serum factors were required for C3 consumption. The C3 proactivator as well as C3 were converted to their activated state by DS in guinea pig and human serum, as revealed by immunoelectrophoretical analysis. DS generated anaphylatoxin activity in serum. It is concluded that DS activates C3 via the alternate pathway of complement activation. This potency of the polyanion might serve as a tentative explanation for its T cell-replacing effect in an antibody-forming system, which was reported b…
Activation of the alternative pathway of complement: efficient fluid-phase amplification by blockade of the regulatory complement protein β1H through…
1981
Current concepts of activation of the alternative pathway of complement (APC) focus on the central role of an amplification mechanism triggered by C3b which is covalently bound to the surfact of activating substances. Using sulfated polyanions as model substances, an efficient fluid-phase activation of complement is demonstrated in contrast to solid-phase activation. It is shown that particulate high-molecular weight sulfated polyanions are capable of reversible binding the guinea pig and human regulatory protein beta1H. This fixation leads to an extensive activation of C3 and factor B because the regulatory function of beta1H is blocked in the fluid-phase C3b-dependent amplification system…
Amnesia and the hippocampus
2006
PURPOSE OF REVIEW: Long-term memory impairments have great medical significance and a considerable health and economic burden. Understanding their cognitive and neuroanatomical underpinnings is of crucial importance. Severe amnesia is usually observed following bilateral hippocampal pathology. This review addresses the precise role of the hippocampus and related medial temporal lobe structures in amnesia. RECENT FINDINGS: Disagreements exist over whether, following selective hippocampal damage: retrograde amnesia for episodic memories is temporally limited or extensive and ungraded; anterograde amnesia involves both recollective and familiarity processes. It is accepted that material specif…
Eight-Membered Rings With Two Heteroatoms 1,3
2022
Eight-membered rings with two heteroatoms in a 1,3-relationship, namely 1,3-diazocine, 2H-1,3-oxazocine, 2H-1,3-thiazocine, 4H-1,3-dioxocin, 4H-1,3-oxathiocin, and 4H-1,3-dithiocin, are discussed in this chapter, that covers the literature from 2007 to October 2020 (SciFindern search) and reports the chemistry of uncondensed derivatives, heterocines fused to carbocycles and heterocycles, as well as bridged heterocines. Among eight-membered 1,3-diheterocines, 1,3-diazocines and 1,3-oxazocines are the two largest classes, based on the number of publications, mostly due to the studies of the synthesis of these cyclic systems, their pharmacological properties and/or their important industrial a…
The Clinical Enzymology of the Complement System
1989
The complement (C) system is one of the most important humoral systems mediating many activities that contribute to inflammation and host defense, e.g. various anaphylatoxin activities, Chemotaxis and opsonization for phagocytosis. The C system is similar to other humoral systems, such as coagulation, fibrinolysis and the kinin system, a multifactoral system whose activation represents sequentially occurring multi-step activation cascades of the “classical” as well as the “alternative” pathway.
Diversity and Evolution of the Phenazine Biosynthesis Pathway
2010
ABSTRACT Phenazines are versatile secondary metabolites of bacterial origin that function in biological control of plant pathogens and contribute to the ecological fitness and pathogenicity of the producing strains. In this study, we employed a collection of 94 strains having various geographic, environmental, and clinical origins to study the distribution and evolution of phenazine genes in members of the genera Pseudomonas , Burkholderia , Pectobacterium , Brevibacterium , and Streptomyces . Our results confirmed the diversity of phenazine producers and revealed that most of them appear to be soil-dwelling and/or plant-associated species. Genome analyses and comparisons of phylogenies inf…
Components of an antigen-/T cell receptor-independent pathway of lymphokine production
1991
The general way to induce the synthesis of lymphokines by T cells is the stimulation through the T cell receptor (TcR) complex which results in an increase of intracellular [Ca2+] and in the activation of a tyrosine kinase as well as of protein kinase C. Lymphokine production induced via the TcR is inhibited by the immunosuppressive drug cyclosporin A (CsA). However, an alternative pathway of lymphokine production exists. Several T lymphocyte clones can synthesize interferon-gamma (IFN-gamma), granulocyte-monocyte colony-stimulating factor, and small amounts of interleukin (IL3) when stimulated with syngeneic or allogeneic accessory cells (AC) plus IL2. In contrast to the TcR pathway the al…
Alternative pathway activation of T cells by binding of CD2 to its cell-surface ligand.
1987
Activation of resting T lymphocytes is initiated by the interaction of cell-surface receptors with their corresponding ligands. In addition to activation through the CD3 (T3)-Ti antigen-receptor complex1, recent experiments have demonstrated induction of T-cell proliferation through the CD2 (T11) molecule2–4, traditionally known as the erythrocyte(E)-receptor, through which T cells can bind red blood cells (RBC)5–7. This 'alternative pathway' of T-cell activation2 was observed in vitro in response to combinations of anti-CD2 monoclonal antibodies (mAbs) that bind to distinct epitopes of CD2, such as mAbs against T112 plus T113 (ref. 2). The physiological importance of this activation pathwa…