Search results for "Piper"
showing 10 items of 632 documents
New conditions for the generation of dianions of carboxylic acids
1998
Abstract Lithium carboxylic acid enediolates are generated efficiently using lithium amides prepared from thienyllithium or butyllithium and either diethylamine, piperazine, N,N′-dibenzylethylenediamine, N-benzylpiperazine or 1,3,3-trimethyl-6-azabicyclo[3.2.1]octane, even in catalytic amounts.
Acetonitrile inclusion complexes of piperazine-based macrocycles
1995
New piperazine-based macrocycles with single small cavities were prepared by using high dilution technique. The inclusion of acetonitrile into the cavity (7, 8) or clathrate formation (3) was studied by 1H-NMR spectroscopy in solution and by X-ray diffraction in the crystalline state. The cycle 3 forms a molecular cleft, a molecular pocket, where the acetonitrile molecule is held by four weak N…H interactions reinforcing the clathrate formation. The cycles 7 and 8 contain a rigid cavity for an exact sterical fit with the methyl group of a linear compound like acetonitrile. The acetonitrile inclusion complex with 7 proved to be stable under normal conditions and was studied by means of therm…
Therapeutic Monitoring of Aripiprazole by HPLC with Column-Switching and Spectrophotometric Detection
2005
Aripiprazole is a novel atypical antipsychotic drug for the treatment of schizophrenia and schizoaffective disorders (1)(2)(3). The drug is metabolized by the cytochrome P450 isoenzymes 3A4 and 2D6 (4). Because of high interindividual variability in the expression of these enzymes, the aripiprazole concentration varies among healthy individuals after administration of the drug (5). In patients, insufficient response or side effects, such as somnolence, akathisia, or nausea, may result from too low or too high drug concentrations. Therapeutic drug monitoring (TDM), which is established practice for many antipsychotic drugs (6)(7), may be helpful for patients treated with aripiprazole. We mea…
Pharmacokinetic rationale for switching from donepezil to galantamine.
2001
Galantamine, the most recently approved acetylcholinesterase inhibitor (AChEI) for use in the United States, has allosteric modulating activity at nicotinic receptors and inhibits acetylcholinesterase. This dual mechanism of action may make galantamine an attractive option for patients with Alzheimer's disease who have not benefited from their current therapy; thus, methods for switching patients from donepezil or rivastigmine to galantamine are needed. Protocols for switching patients from one AChEI to another must consider both the time required for washout of the first drug and the rate of dose escalation of the second drug. Both issues depend on the pharmacodynamics, pharmacokinetics, a…
Intracellular retention of ABL kinase inhibitors determines commitment to apoptosis in CML cells
2012
PLoS one 7(7), e40853 (2012). doi:10.1371/journal.pone.0040853
Targeting BCL-2 family proteins to overcome drug resistance in non-small cell lung cancer.
2007
Cytotoxic chemotherapies are standard of care for patients suffering from advanced non-small cell lung cancer (NSCLC). However, objective responses are only achieved in 20% of cases and long-term survival is rarely observed. Clinically applied anticancer drugs exert at least some of their activities by inducing apoptosis. A critical step in apoptotic signal transduction is the permeabilization of the mitochondrial outer membrane (MOM), which is regulated by the BCL-2 family of proteins. Hence, therapeutic targeting of BCL-2 proteins is a promising approach to increase the drug-sensitivity of cancers. To this end we have assessed the impact of conditional expression of the proapoptotic multi…
Mechanisms underlying diabetes enhancement of endothelin-1-induced contraction in rabbit basilar artery
2004
The influence of alloxan-induced diabetes on the reactivity of rabbit basilar artery to endothelin-1 was examined. Endothelin-1 induced concentration-dependent contraction of basilar arteries that was higher in diabetic than in control rabbits. Endothelium removal produced a higher enhancement of the endothelin-1-induced contraction in control than in diabetic rabbits. N(G)-nitro-L-arginine (L-NOArg) enhanced the maximal contraction induced by endothelin-1 in control rabbits and potentiated this response in diabetic rabbits. Endothelin ETA receptor antagonist, cyclo(D-Asp-Pro-D-Val-Leu-D-Trp) (BQ-123), inhibited endothelin-1-induced contraction in both rabbit groups. Endothelin ETB receptor…
Behavioural responses of breeding arctic sandpipers to ground-surface temperature and primary productivity
2021
Most birds incubate their eggs, which requires time and energy at the expense of other activities. Birds generally have two incubation strategies: biparental where both mates cooperate in incubating eggs, and uniparental where a single parent incubates. In harsh and unpredictable environments, incubation is challenging due to high energetic demands and variable resource availability. We studied the relationships between the incubation behaviour of sandpipers (genus Calidris) and two environmental variables: temperature and a proxy of primary productivity (i.e. NDVI). We investigated how these relationships vary between incubation strategies and across species among strategies. We also stud…
Chemical Composition and Antimicrobial Activity of the Essential Oil from Flowers of Eryngium triquetrum (Apiaceae) Collected Wild in Sicily
2016
The chemical composition of the essential oil from flowers of Eringium triquetrum Vahl. collected in Sicily was evaluated by GC and GC-MS. The main components were pulegone (50.6%), piperitenone (30.5%) and menthone (7.0%). Comparison of this oil with other studied oils of Eringium species is discussed. The oil showed good antibacterial and antifungal activities against some microorganisms that infest historical art works.
Caffeate and piperidine-3-ol derivatives from the stem bark of Cassia sieberiana
2019
A new caffeate derivative from the ethanol extract of the stem bark of Cassia sieberiana DC. is described herein along with the known secondary metabolites spectaline (2), iso-6-cassine (3), 3-O-methyl-chiro-inositol (4), monobehenin (5), octyl nonadecyloate (6), β-sitosterol (7), stigmasterol (8) and sitosterol 3-O-β-D-glucopyranoside (9). The chemical structures were elucidated by means of various spectroscopic and spectrometric techniques. Extract and isolated compounds were devoid of inhibitory action against the herein selected bacterial strains (MICs > 256 μg/mL) but showed capacities to reduce 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical (EC50 < 3 μg/mL) considerably better than the …