Search results for "AMPT"
showing 10 items of 114 documents
Meiofauna of the profundal zone of the northern part of Lake Ladoga as an indicator of pollution
1996
Benthic meiofauna was sampled at 19 stations, mainly in the northern part of Lake Ladoga, from depths between 13 and 199 m and from types of environment ranging from sheltered areas near pollution sources to less polluted open areas. About 80 taxa were identified, of these 70 to the species level. The greatest numbers of species were oligochaetes (24 species) and harpacticoids (8 species). Certain quantitative ratios of meiofauna were shown to be correlated with environmental data. The species of the oligochaete families Lumbriculidae and Aeolosomatidae and the harpacticoids as a collective group, excluding Canthocamptus staphylinus, were most clearly confined to the less eutrophied environ…
Synthesis and biological evaluation of a D-ring-contracted analogue of lamellarin D
2017
A D-ring contracted analogue of the strongly cytotoxic marine pyrrole alkaloid lamellarin D was synthesized and investigated for its antiproliferative action towards a wild type and a multidrug resistant (MDR) cancer cell line. The compound was found to inhibit tumor cell growth at submicromolar concentrations and showed a lower relative resistance in the MDR cell line than the antitumor drug camptothecin to which lamellarin D shows cross resistance and with which lamellarin D shares the same binding site.
Design of enzyme-mediated controlled release systems based on silica mesoporous supports capped with ester-glycol groups
2012
[EN] An ethylene glycol-capped hybrid material for the controlled release of molecules in the presence of esterase enzyme has been prepared. The final organic-inorganic hybrid solid S1 was synthesized by a two-step procedure. In the first step, the pores of an inorganic MCM-41 support (in the form of nanoparticles) were loaded with [Ru(bipy) 3]Cl 2 complex, and then, in the second step, the pore outlets were functionalized with ester glycol moieties that acted as molecular caps. In the absence of an enzyme, release of the complex from aqueous suspensions of S1 at pH 8.0 is inhibited due to the steric hindrance imposed by the bulky ester glycol moieties. Upon addition of esterase enzyme, del…
Multifunctional nanocarriers for biomedical applications
2013
Polymeric vesicles (Pluronic ® L-121) loaded with magnetic nanoparticles (MNP) and an anti-cancer drug (camptothecin) were prepared continuously in a micro mixing device. Characterization by TEM confirmed the successful incorporation of the MNP and DLS measurements showed a relatively narrow size distribution of the hybrid polymersomes. A very high drug loading of camptothecin (100 μg/ml in the polymersome formulation) was reached and a drug release study of loaded magnetic polymersomes has shown a sustained camptothecin release over several days. Carboxylation of Pluronic ® L-121 was performed and enabled a further surface functionalization with bombesin, a 14 amino acid peptide, which bin…
Constituents of regenerated plants of Ophiorrhiza pumila; formation of a new glycocamptothecin and predominant formation of (3R)-deoxypumiloside over…
1997
Abstract The regeneration of plantlets was successful from Ophiorrhiza pumila callus cultures, from which a new glucosyloxy camptothecin, 9-β-glucosyloxycamptothecin, together with 15 metabolites including six camptothecin-related alkaloids was isolated. (3S)-Deoxypumiloside, one of the plausible biogenetic precursors of camptothecin, could not be found, whereas the (3R) epimer was isolated from the regenerated plants.
Utilizing inherent fluorescence of therapeutics to analyze real-time uptake and multi-parametric effector kinetics.
2011
Abstract The precise detection of pharmaceutical drug uptake and knowledge of a drug’s efficacy at the single-cell level is crucial for understanding a compound’s performance. Many pharmaceutical drugs, like the model substances Doxorubicin, Mitoxantrone or Irinotecan, have a distinctive natural fluorescence that can be readily exploited for research purposes. Utilizing this respective natural fluorescence, we propose a method analyzing simultaneously in real-time the efficiency, effects and the associated kinetics of compound-uptake and efflux in mammalian cells by flow cytometry. We show that real-time flow cytometric quantification of compound-uptake is reliably measured and that analyzi…
Selected Secondary Plant Metabolites for Cancer Therapy
2015
Secondary plant metabolites reveal numerous biological activities making them attractive as resource for drug development of human diseases. As the majority of cancer drugs clinically established during the past half century is derived from nature, cancer researchers worldwide try to identify novel natural products as lead compounds for cancer therapy. Natural products are considered as promising cancer therapeutics, either as single agents or in combination protocols, to enhance the antitumor activity of additional therapeutic modalities. Most natural compounds exert pleotrophic effects and modulate various signal transduction pathways. A better understanding of the complex mechanisms of a…
Farmaci inibitori delle topoisomerasi
2020
Le DNA-topoisomerasi, identificate per la prima volta nel 1971, sono enzimi chiave nella regolazione della struttura topologica del DNA.
The CD95/CD95 ligand system is not the major effector in anticancer drug-mediated apoptosis.
1998
Many anticancer drugs are able to induce apoptosis in tumor cells but the mechanisms underlying this phenomenon are poorly understood. Some authors reported that the p53 tumor suppressor gene may be responsible for drug-induced apoptosis; however, chemotherapy-induced apoptosis can also be observed in p53 negative cells. Recently, doxorubicin (DXR) was reported to induce CD95L expression to mediate apoptosis through the CD95/CD95L system. Thus, an impairment of such a system may be involved in drug resistance. We evaluated the in vitro antitumor activity of several cytotoxic drugs on two human p53-negative T-cell lymphoma cell lines, the HUT78-B1 CD95L-resistant cell line and the HUT78 pare…
Il ruolo della megaforma
2003
Kenneth Frampton espone le sue teorie sui rapporti tra “megalopoli” e progetto di architettura a grande scala.