Search results for "Polyenes"
showing 10 items of 13 documents
Central nervous system involvement at first relapse in patients with acute promyelocytic leukemia treated with all-trans retinoic acid and anthracycl…
2009
Background The prevalence of and risk factors for central nervous system recurrence in patients with acute promyelocytic leukemia are not well established and remain a controversial matter. Design and Methods Between 1996 and 2005, 739 patients with newly diagnosed acute promyelocytic leukemia enrolled in two consecutive trials (PETHEMA LPA96 and LPA99) received induction therapy-with all-trans retinoic acid and idarubicin. Consolidation therapy comprised three courses of anthracycline monochemotherapy (LPA96), with all-trans retinoic acid and reinforced doses of idarubicin in patients with an intermediate or high risk of relapse (LPA99). Central nervous system prophylaxis was not given. Re…
Prospective study of amphotericin B formulations in immunocompromised patients in 4 European countries
2005
Background. Amphotericin B is a widely used broad-spectrum antifungal agent, despite being associated with significant adverse events, including nephrotoxicity. Methods. The present prospective study collected data on outcomes for 418 adult patients treated consecutively with polyenes in hematology and oncology wards in 20 hospitals in Europe. Results. Patients initially received amphotericin B deoxycholate (62% of patients), liposomal amphotericin B (27%), or other lipid formulations of amphotericin B (11%). Of the patients initially treated with amphotericin B deoxycholate, 36% had therapy switched to lipid formulations of amphotericin B, primarily because of increased serum creatinine le…
Choosing the Right Antifungal Agent in ICU Patients
2019
Fungi are responsible for around 20% of microbiologically documented infections in intensive care units (ICU). In the last decade, the incidence of invasive fungal infections (IFI), including candidemia, has increased steadily because of increased numbers of both immunocompromised and ICU patients. To improve the outcomes of patients with IFI, intensivists need to be aware of the inherent challenges. This narrative review summarizes the features of routinely used treatments directed against IFI in non-neutropenic ICU patients, which include three classes of antifungals: polyenes, azoles, and echinocandins. ICU patients' pathophysiological changes are responsible for deep changes in the phar…
Theoretical study of the low‐lying states of trans‐1,3‐butadiene
1992
We present extensive ab initio calculations on the low‐lying electronic states of trans‐1,3‐butadiene within the multireference configuration interaction (MRCI) framework by selecting the configurations with a perturbative criterion. The X 1Ag ground state and 1 3Bu, 1 3Ag, 2 1Ag, and 1 1Bu valence excited states have been calculated at a fixed geometry. The results obtained are in good agreement with previous experimental and calculated values, and could help to understand polyene spectroscopy, photochemistry, and photophysics. The advantages of a MRCI method where the most important contributions to the total MRCI wave function, perturbatively selected, are treated variationally, and the …
General occurrence of polar twisted minima in the ionic singlet excited surfaces of polyenes
1982
Except for a few cases, the lowest closed shell SCF solutions for the twisted geometries of polyenes involves delocalized nonpolarized MO’s, and represents a meaningless mixture of radicalar gound state and ionic excited states. Higher (quasi) solutions allow a realistic approach of the polarized ionic states. Orthogonality to the radicalar ground state may be imposed without important loss of energy. Further extensive CI does not modify significantly the situation. These statements are illustrated through ab initio calculations of butadiene and hexatriene. This approach allows us to show that slight distortions stablize polar minima even in ’’homosymmetric’’ molecules such as all‐trans hex…
Filter-based infrared detectors for high temperature size exclusion chromatography analysis of polyolefins: calibration with a small number of standa…
2012
Infrared detection has been shown to be very appropriate for high temperature analysis of polyolefins. After some early reports in which dispersive or single-band filter-based detectors were applied, Fourier transform detectors have been described for this application, in order to improve the method sensitivity. Modern simple filter-based detectors prove, however, comparable sensitivity while providing a number of practical advantages when coupled to chromatographic systems: reduced cell volume, simplified hardware, continuous generation of absorbance chromatograms, as well as simpler data collection and processing. A practical method for calibration, using multiple-band signals obtained wi…
Towards an accurate molecular orbital theory for excited states : Ethene, butadiene, and hexatriene
1993
A newly proposed quantum chemical approach for ab initio calculations of electronic spectra of molecular systems is applied to the molecules ethene, trans‐1,3‐butadiene, and trans‐trans‐1,3,5‐hexatriene. The method has the aim of being accurate to better than 0.5 eV for excitation energies and is expected to provide structural and physical data for the excited states with good reliability. The approach is based on the complete active space (CAS) SCF method, which gives a proper description of the major features in the electronic structure of the excited state, independent of its complexity, accounts for all near degeneracy effects, and includes full orbital relaxation. Remaining dynamic ele…
The effect of cyclosporin A, FK506 and rapamycin on the murine contact sensitivity reaction
1998
We have evaluated the effects of three potent immunosuppressive agents, cyclosporin A (CsA), FK506 and rapamycin, on the murine contact sensitivity (CS) reaction to the hapten trinitrochlorobenzene. Development of CS reaction requires participation of three distinct T cell subsets: alphabeta+, CD4+ T lymphocytes, which are the classical effector cell of the CS reaction, gammadelta+ T lymphocytes, and alphabeta+, double-negative (CD4- CD8-) T lymphocytes that express the B220 molecule and produce IL-4. We found that all three drugs inhibit the development of the CS reaction, but they affect different target cells. In fact, rapamycin and FK-506 block both alphabeta+, CD4+ and gammadelta+ T ly…
DFT studies on the structural and vibrational properties of polyenes
2015
Detailed density functional theory (DFT) calculations on the structure and harmonic frequencies of model all-trans and all-cis polyenes were undertaken. For the first time, we report on the convergence of selected B3LYP/6-311++G** and BLYP/6-311++G** calculated structural parameters resulting from a systematic increase in polyene size (chains containing 2 to 14 C = C units). The limiting values of the structural parameters for very long chains were estimated using simple three-parameter empirical formulae. BLYP/6-311++G** calculated ν(C = C) and ν(C–C) frequencies for all-trans and all-cis polyenes containing up to 14 carbon–carbon double bonds were used to estimate these values for very lo…
Filipin labelling and intramembrane particles on the membranes of early and later autophagic vacuoles in Ehrlich ascites cells
1987
Cholesterol and intramembrane particle distribution on autophagic vacuole membranes was studied in Ehrlich ascites cells using filipin labelling and freeze-fracture electron microscopy. Unsaturated fatty acids were stained using imidazole-buffered osmium tetroxide. Autophagocytosis was induced with vinblastine, and early autophagic vacuoles were accumulated by lowering the ATP level in the cells with iodoacetate. Filipin labelling was observed in the limiting membranes of later, apparently hydrolase-containing autophagic vacuoles, whereas the most newly-formed, doublemembrane limited vacuoles were not labelled. The limiting membranes of late, residual body-type vacuoles either showed patchy…