Search results for "Ethylene"
showing 10 items of 2589 documents
SYNTHESIS, CHARACTERIZATION AND IN VITRO CYTOTOXICITY STUDIES OF A MACROMOLECULAR CONJUGATE OF PACLITAXEL BEARING OXYTOCIN AS TARGETING MOIETY.
2007
The present study describes the experimental synthetic procedure and the characterization of a new polyaspartamide macromolecular prodrug of paclitaxel, bearing oxytocin residues as targeting moieties. In vitro stability studies of bioconjugate, performed in media mimicking biological fluids (buffer solutions at pH 7.4 and 5.5) and in human plasma, evidenced the high stability of the targeting portion (oxytocin)-polymer linkage and the ability of this conjugate to release linked paclitaxel in a prolonged way in plasma. Moreover, preliminary in vitro antiproliferative studies, carried out on MCF-7 cells, that are oxytocin receptor positive cells, showed that the polymeric conjugate has the s…
Long-term stability study of clofarabine injection concentrate and diluted clofarabine infusion solutions
2011
Purpose: The aim of this study was to investigate the physicochemical stability of clofarabine (CAFdA) injection concentrate and ready-to-use CAFdA infusion solutions over a prolonged period of 28 days. Methods: To determine the stability of CAFdA infusion solutions, the injection concentrate (Evoltra®, 1 mg/mL, Genzyme) was diluted either with 0.9% sodium chloride or 5% glucose infusion solution. The resulting concentrations of 0.2 mg/mL or 0.6 mg/mL, respectively, were chosen to represent the lower and upper limit of the ordinary concentration range. Test solutions were stored under refrigeration (2–8°C) or at room temperature either light protected or exposed to light. CAFdA concentrati…
Boceprevir is highly effective in treatment-experienced hepatitis C virus-positive genotype-1 menopausal women
2014
AIM: To investigate the safety/efficacy of Boceprevirbased triple therapy in hepatitis C virus (HCV)-G1 menopausal women who were historic relapsers, partial-responders and null-responders. METHODS: In this single-assignment, unblinded study, we treated fifty-six menopausal women with HCV-G1, 46% F3-F4, and previous PEG-α/RBV failure (7% null, 41% non-responder, and 52% relapser) with 4 wk lead-in with PEG-IFNα2b/RBV followed by PEGIFNα2b/RBV+Boceprevir for 32 wk, with an additional 12 wk of PEG-IFN-α-2b/RBV if patients were HCV-RNA-positive by week 8. In previous null-responders, 44 wk of triple therapy was used. The primary objective of retreatment was to verify whether a sustained virolo…
Titanium Complexes Stabilized by a Sulfur‐Bridged Chelating Bis(aryloxo) Ligand as Active Catalysts for Olefin Polymerization
2004
The mixed-ligand complexes [Ti2(μ-OR)2(OR)2(κ3-tbop)2] (1a) for R = Me and (1b) R = Et were prepared by the reaction of Ti(OR)4 and H2tbop {H2tbop = 2,2′-thiobis[4-(1,1,3,3-tetramethylbutyl)phenol]} in methanol. Treatment of 1a and 1b with AlMe3 led to the substitution of terminal alkoxy groups to create the organometallic compounds [Ti2(μ-OR)2(κ3-tbop)2(Me)2] (2a) for R = Me and (2b) for R = Et. Controlled hydrolysis of 2b causes the evolution of methane and the formation of the titanoxane compounds [{Ti2(μ-OEt)2(κ3-tbop)2}2(μ-O)2]·2CH2Cl2 (3). Structures of 1a, 1b, 2a, 2b, and 3 were confirmed by NMR spectroscopy; 1b and 3 were further investigated with X-ray crystallography. Compounds 1a…
Ethylene modulates gene expression in cells of the marine sponge Suberites domuncula and reduces the degree of apoptosis.
1999
Sponges (phylum Porifera) live in an aqueous milieu that contains dissolved organic carbon. This is degraded photochemically by ultraviolet radiation to alkenes, particularly to ethylene. This study demonstrates that sponge cells (here the demosponge Suberites domuncula has been used), which have assembled to primmorphs, react to 5 microM ethylene with a significant up-regulation of intracellular Ca(2+) concentration and with a reduction of starvation-induced apoptosis. In primmorphs from S. domuncula the expression of two genes is up-regulated after exposure to ethylene. The cDNA of the first gene (SDERR) isolated from S. domuncula encodes a potential ethylene-responsive protein, termed ER…
Multilayer capsules: a promising microencapsulation system for transplantation of pancreatic islets
2001
In 1980, Lim and Sun introduced a microcapsule coated with an alginate/polylysine complex for encapsulation of pancreatic islets. Characteristic to this type of capsule is, that it consists of a plain membrane which is formed during a single procedural step. With such a simple process it is difficult to obtain instantly a membrane optimized with respect to all the properties requested for islet transplantation. To overcome these difficulties, it is recommended to build up the membrane in several consecutive steps, each optimized for a certain property. In this study, we have analysed such a multilayer microcapsule for the encapsulation of pancreatic islets. Therefore, empty and islet contai…
Influence of Remote Substituents on the Equatorial/Axial Selectivity in the Monooxygenation of Methylene C−H Bonds of Substituted Cyclohexanes
2001
The reactivity of individual C--H bonds in the methyl(trifluoromethyl)dioxirane TFDO oxygenation of stereogenic methylene groups in conformationally homogeneous monosubstituted cyclohexanes (2) has been determined. The unexpectedly high occurrence of O-atom insertion into C--H(ax) bonds suggests an in plane trajectory attack in the oxygenation while the diastereoselectivity of the reaction is qualitatively interpreted on the basis of the distinct hyperconjugative stabilization by the substituent of diastereomeric transition states due to long-range through bond interactions.
The (2-phenyl-2-trimethylsilyl)ethyl-(PTMSEL)-linker in the synthesis of glycopeptide partial structures of complex cell surface glycoproteins.
2003
The (2-phenyl-2-trimethylsilyl)ethyl-(PTMSEL) linker represents a novel fluoride-sensitive anchor for the solid-phase synthesis of protected peptides and glycopeptides. Its cleavage is achieved under almost neutral conditions using tetrabutylammonium fluoride trihydrate in dichloromethane thus allowing the construction of complex molecules sensitive to basic and acidic media commonly required for the cleavage of standard linker systems. The advantages of the PTMSEL linker are demonstrated in the synthesis of glycopeptides from the liver intestine (LI)-cadherin and the mucin MUC1, bearing carbohydrate moieties such as N-linked chitobiose or O-linked sialyl-T(N)-residues. The synthesis of the…
Methylation as an effective way to generate SOD-activity in copper complexes of scorpiand-like azamacrocyclic receptors
2018
Abstract Methylation of the secondary amine groups of a scorpiand-type ligand consisting of a pyridine spacer connected through methylene groups to a tris(2-aminomethyl) unit with the pendant arm further functionalised with a 3-pyridine unit leads to a ligand whose Cu(II) complex exhibits threefold enhanced SOD activity with respect to the non-methylated ligand. Potentiometric studies indicate the formation of [CuL] 2+ species with a stability three orders of magnitude lower than that formed with the related non-methylated ligand. Kinetic studies indicate that methylation of the secondary nitrogens causes a deceleration of both the complex formation and the acid-induced dissociation of the …
Darstellung einiger oligomerer Cyclo{oligo[(2-hydroxy-1,3-phenylen)methylen]}e. Spektroskopische Untersuchung ihrer Pseudorotation
1978
Es wird die Darstellung von Cyclo{tris[(2-hydroxy-5-methyl-1,3-phenylen)methylen]-(2-hydroxy-5-tert-butyl-1,3-phenylen)methylen} (4a), Cyclo{bis[(2-hydroxy-5-methyl-1,3-phenylen)methylen]-bis[(2-hydroxy-5-tert-butyl-1,3-phenylen)methylen]}(4b) und Cyclo-{pentakis[(2-hydroxy-5-methyl-1,3-phenylen)methylen]} (4c) beschrieben. Die IR-Spektren zeigen, das die phenolischen Hydroxygruppen der Vierringverbindungen 4a und 4b intramolekulare, vom Losungs(CCl4)- oder Zerteilungsmittel (KBr) weitgehend unabhangige Wasserstoffbrucken bilden, die bei der pentameren Ringverbindung 4c schwacher sind. Anhand der 1H-NMR-Spektren last sich bei diesen Verbindungen eine Pseudorotation nachweisen. Die Massenspe…