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showing 10 items of 1669 documents
New Fluorinated Peptidomimetics through Tandem Aza-Michael Addition to α-Trifluoromethyl Acrylamide Acceptors: Synthesis and Conformational Study in …
2009
A range of partially modified retro (PMR) psi[NHCH(2)] peptide mimetics containing a hydrolytically stable CH(2)CH(CF(3))CO unit have been synthesized. The first kind of peptidomimetics is obtained from the highly efficient aza-Michael addition of different amines to alpha-trifluoromethyl acrylamide acceptors. Subsequent deprotection of the amino group furnishes the key common intermediate for the synthesis of other families of peptidomimetics: dipeptides, tripeptides, peptidomimetics containing a urea moiety, and structures containing two units of alpha-trifluoromethyl-beta(2)-alanine. Finally, a conformational study of several of the newly synthesized peptidomimetics, performed with the a…
Characterization of sulfobetaine monomers by nuclear magnetic resonance spectroscopy: a note
1995
A set of zwitterionic monomers bearing the 3-ammoniopropanesulfonate moiety is analysed in CDCl3, CD3OD and D2O by one- and two-dimensional H-1 n.m.r. and C-13 n.m.r. spectroscopy. Absolute and relative positions of the n.m.r, signals are determined depending on the solvent used; the refined assignments of the signals in the vicinity of the ammonium group deviate from previously proposed assignments based on standard n.m.r, shift tables. Still, there is no convincing evidence for a special ring current effect due to a six-membered ring conformation of the betaine moiety.
Synthesis and characterization of bi-functional photorefractive polymers
2001
Abstract A novel bi-functional photorefractive acrylate polymer with pendant carbazolyl groups and azo derivatives as side chains was synthesized, in which azo derivatives as electro-optic chromophores and carbazolyl as photoconductive moiety were covalently linked on the acrylate backbone. Photorefractive experiments showed that a high two-beam coupling gain coefficient of 93 cm −1 , diffraction efficiency of 12% and electro-optic coefficient of 26 pm/V were obtained. With increasing writing beam's intensity, the two-beam coupling enhanced gradually, and then reached saturation. Using the method of four-wave mixing, the photoisomerization grating was observed.
Acute Nonlymphocytic Leukemia in Adults: Pathophysiology, Status of Current Therapy, and New Approaches
1987
Recent information concerning the cell biology of leukemias has provided new insights into the pathophysiology and pathogenesis of acute leukemia, involving the detection of leukemia viruses, oncogenes and their products, and the discovery of factors supporting clonal leukemic growth. Murine, avian, and cat leukemia viruses are well characterized. To date, only HTLV I appears to be a likely candidate as a human leukemia virus. For both avian and murine viruses, there is a fundamental classification distinction between long-latency viruses (LLV) and acute transforming viruses (ATV). The ATV are replication defective and must be propagated with a helper virus. They have within their genome an…
Impact Of The Pretreatment Characteristics As Well As Cyto- and Molecular-Genetic Profile On Outcome After Relapse In Acute Myeloid Leukemia
2013
Abstract Background Cyto- and molecular-genetic abnormalities evaluated at initial diagnosis are the most powerful prognostic and in part also predictive markers in acute myeloid leukemia (AML) with regard to achievement of complete remission (CR) and survival. Nonetheless, after relapse the prognostic impact of clinical characteristics and genetic abnormalities assessed at initial diagnosis with respect to achievement of subsequent CR and survival are less clear. Aims To evaluate the probability of CR achievement and survival in relapsed AML patients in correlation to clinical characteristics and genetic abnormalities assessed at initial diagnosis as well as treatment strategy. Methods The…
Towards More Specificity and Effectivity in the Antileukemia Immune Response
2014
Experimental and clinical studies have shown that alloreactive T-cell responses derived from donor lymphocytes can effectively eliminate leukemia cells after allogeneic hematopoietic stem cell transplantation. However, there are still too many patients in whom this graft-versus-leukemia reactivity is insufficient to prevent leukemia relapse or who suffer from severe alloreactivity to nonmalignant host tissues also mediated by donor-derived T cells. Therefore, various conceptually different approaches have been developed at the level of donor T cells in order to improve the efficacy of leukemia-directed immunity while reducing the incidence of unwanted graft-versus-host disease. As outlined …
Treatment Results In Acute Myeloid Leukemia Over a Time Period Of 20 Years: Analysis Of The German-Austrian Acute Myeloid Leukemia Study Group (AMLSG)
2013
Abstract Background Overall survival (OS) in acute myeloid leukemia (AML) treated with intensive chemotherapy has improved over the last 20 year especially in younger adults (18-60 years) but still remains poor in older patients (>60 years) (Döhner et al. Blood 2010). The German-Austrian AMLSG performed controlled prospective treatment trials since 1993 starting with a risk-adapted approach (phase I, 1993-1997), followed by randomized and risk-adapted treatment strategies based on cytogenetic risk groups (phase II, 1997-2002); since 2003 addition of differentiating agents and HiDAC inhibitors to intensive induction therapy was evaluated (phase III, 2003-2007). Of note, until 2007 younger…
Highly Diastereoselective Michael Reaction of (S)‐Mandelic Acid Enolate. Chiral Benzoyl Carbanion Equivalent Through an Oxidative Decarboxylation of …
2002
The reaction of the lithium enolate of the 1,3-dioxolan-4-one derived from optically active (S)-mandelic acid and pivalaldehyde with α,β-unsaturated carbonyl compounds proceeds readily to give the corresponding Michael adducts in good yields and high diastereoselectivity. Subsequent basic hydrolysis of the acetal and oxidative decarboxylation of the α-hydroxyacid moiety provides chiral 2-substituted 1,4-dicarbonyl compounds with very high enantiomeric excesses.
Membrane-Bound F1 ATPase from Micrococcus Sp. ATCC 398E. Purification and Characterization by Affinity Chromatography
1976
A chemically reactive ATP analogue, 6-[(3-carboxy-4-nitrophenyl)thio]-9-β-D-ribofuranosylpurine 5′-triphosphate (Nbs6ITP) has been synthesized. It has the ability to form stable thioether bonds between the 6-position of the purine ring and aliphatic mercapto groups. The nucleotide moiety of the reagent has been covalently bound to agarose, via iminobispropylamine and N-acetyl-homocysteine as spacer with the purpose of producing an affinity chromatography material. The affinity matrix binds solubilized F1 ATPase from a crude extract of Micrococcus sp. membranes. Afterwards the enzyme can be selectively eluted from the column at a defined ATP concentration. This method is superior to the conv…
Lymphoma cell apoptosis in the liver induced by distant murine cytomegalovirus infection.
2006
ABSTRACTCytomegalovirus (CMV) poses a threat to the therapy of hematopoietic malignancies by hematopoietic stem cell transplantation, but efficient reconstitution of antiviral immunity prevents CMV organ disease. Tumor relapse originating from a minimal residual leukemia poses another threat. Although a combination of risk factors was supposed to enhance the incidence and severity of transplantation-associated disease, a murine model of a liver-adapted B-cell lymphoma has previously shown a survival benefit and tumor growth inhibition by nonlethal subcutaneous infection with murine CMV. Here we have investigated the underlying antitumoral mechanism. Virus replication proved to be required, …