1,486 research outputs found

    Verbal Episodic Memory and Endogenous Estradiol: An Association in Patients with Mild Cognitive Impairment and Alzheimer's Disease

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    In the continuum of patients with Alzheimer's disease (AD), mild cognitive impairment (MCI), and normal controls, a possible association of verbal memory and endogenous estradiol (E2) levels was investigated. Verbal episodic memory was measured with a german version of the California verbal memory test (CVLT). Results were controlled for apolipoprotein E (ApoE) phenotype. We studied 37 controls, 32 MCIs and 117 ADs. Groups differed in all trials of the CVLT (P < 0.001) and in E2 levels (P < 0.001). E2 levels differed significantly between groups only among females (P < 0.001). In females correcting for age and ApoE, there was an overall correlation between CVLT delayed recall and level of E2 (P = 0.025). Stepwise regression analyses found E2 level to be a significant predictor for CVLT delayed recall (P < 0.001). It may be concluded that lower E2 levels occur more in the course of the disease than may be considered as a risk factor per se

    Dioxygen Reactivity of Biomimetic Fe(II) Complexes with Noninnocent Catecholate, \u3cem\u3eo\u3c/em\u3e-Aminophenolate, and \u3cem\u3eo\u3c/em\u3e-Phenylenediamine Ligands

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    This study describes the O2 reactivity of a series of high-spin mononuclear Fe(II) complexes each containing the facially coordinating tris(4,5-diphenyl-1-methylimidazol-2-yl)phosphine (Ph2TIP) ligand and one of the following bidentate, redox-active ligands: 4-tert-butylcatecholate (tBuCatH–), 4,6-di-tert-butyl-2-aminophenolate (tBu2APH–), or 4-tert-butyl-1,2-phenylenediamine (tBuPDA). The preparation and X-ray structural characterization of [Fe2+(Ph2TIP)(tBuCatH)]OTf, [3]OTf and [Fe2+(Ph2TIP)(tBuPDA)](OTf)2, [4](OTf)2 are described here, whereas [Fe2+(Ph2TIP)(tBu2APH)]OTf, [2]OTf was reported in our previous paper [Bittner et al., Chem.—Eur. J. 2013, 19, 9686–9698]. These complexes mimic the substrate-bound active sites of nonheme iron dioxygenases, which catalyze the oxidative ring-cleavage of aromatic substrates like catechols and aminophenols. Each complex is oxidized in the presence of O2, and the geometric and electronic structures of the resulting complexes were examined with spectroscopic (absorption, EPR, Mössbauer, resonance Raman) and density functional theory (DFT) methods. Complex [3]OTf reacts rapidly with O2 to yield the ferric-catecholate species [Fe3+(Ph2TIP)(tBuCat)]+ (3ox), which undergoes further oxidation to generate an extradiol cleavage product. In contrast, complex [4]2+ experiences a two-electron (2e–), ligand-based oxidation to give [Fe2+(Ph2TIP)(tBuDIBQ)]2+ (4ox), where DIBQ is o-diiminobenzoquinone. The reaction of [2]+ with O2 is also a 2e– process, yet in this case both the Fe center and tBu2AP ligand are oxidized; the resulting complex (2ox) is best described as [Fe3+(Ph2TIP)(tBu2ISQ)]+, where ISQ is o-iminobenzosemiquinone. Thus, the oxidized complexes display a remarkable continuum of electronic structures ranging from [Fe3+(L2–)]+ (3ox) to [Fe3+(L•–)]2+ (2ox) to [Fe2+(L0)]2+ (4ox). Notably, the O2 reaction rates vary by a factor of 105 across the series, following the order [3]+ \u3e [2]+ \u3e [4]2+, even though the complexes have similar structures and Fe3+/2+ redox potentials. To account for the kinetic data, we examined the relative abilities of the title complexes to bind O2 and participate in H-atom transfer reactions. We conclude that the trend in O2 reactivity can be rationalized by accounting for the role of proton transfer(s) in the overall reaction

    Mathematical model for determining the viscoelastic properties of soft tissues using indentation tests

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    grants projects TG01010117 – PROSYKO and SGS Technical University of Liberec

    Use of Yeast Lysate in Women with Recurrent Vulvovaginal Candidiasis

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    AbstractVulvovaginal candidiasis (VVC) affects a significant number of women, especially in working age. In an estimated 75% of women an episode of acute vulvovaginal candidiasis occurs during lifetime and another 5–10% of women develop recurrent vulvovaginal candidiasis (RVVC). This is mainly characterized by intense burning, itching, pain, abnormal discharge, dyspareunia. Immune response to candidiasis is both cellular (CMI) (natural protection mechanisms) and humoral (antibody production). Understanding the principles of immunity in candidiasis is also important for development of candida vaccines.CANDIVAC contains lyophilized Candida lysate (C. albicans, C. krusei, C. glabrata) together with immunostimulatory bacterial strain of Propionibacterium acnes. The product is taken orally in capsules for 10 days followed by a 20-day pause. It is administered for 3 to 6 months. The product has been tested in a total of 75 women at the age of 18–45 years. In these women at least 4 episodes of vulvovaginal candidiasis have been microscopically or laboratory diagnosed during the last 12 months. Following CANDIVAC administration, statistically significant changes occurred in the evaluation of subjective and some objective criteria. The most important marker of product efficiency is a significant reduction in recurrence compared to the recent state. This criterion has a fundamental importance in patient satisfaction. Before medication the patients suffered from at least 4 attacks, while after medication an attack occurred in only 31% of women and more than 2 attacks in only 3% of treated women.Compromised balance of immune system plays a major role in recurrent vulvovaginal candidiasis. Specific oral product CANDIVAC, prepared from the most common strains of yeast infections, supports immune mechanisms, ensuring resistance of the human organism against yeasts. Its administration significantly prolongs remission, leads to a reduction in application of antimycotics and also changes properties of cellular and humoral immunity in medicated patients

    Matrix models and QCD with chemical potential

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    The Random Matrix Model approach to Quantum Chromodynamics (QCD) with non-vanishing chemical potential is reviewed. The general concept using global symmetries is introduced, as well as its relation to field theory, the so-called epsilon regime of chiral Perturbation Theory (echPT). Two types of Matrix Model results are distinguished: phenomenological applications leading to phase diagrams, and an exact limit of the QCD Dirac operator spectrum matching with echPT. All known analytic results for the spectrum of complex and symplectic Matrix Models with chemical potential are summarised for the symmetry classes of ordinary and adjoint QCD, respectively. These include correlation functions of Dirac operator eigenvalues in the complex plane for real chemical potential, and in the real plane for imaginary isospin chemical potential. Comparisons of these predictions to recent Lattice simulations are also discussed

    Synthesis and Structural Characterization of Iron(II) Complexes with Tris(imidazolyl)phosphane Ligands: A Platform for Modeling the 3-Histidine Facial Triad of Nonheme Iron Dioxygenases

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    Several monoiron(II) complexes containing tris(imidazolyl)phosphane (TIP) ligands have been prepared and structurally characterized by using X-ray crystallography and NMR spectroscopy. Two TIP ligands were employed: tris(2-phenylimidazol-4-yl)phosphane (4-TIPPh) and tris(4,5-diphenyl-1-methylimidazol-2-yl)phosphane (2-TIPPh2). These tridentate ligands resemble the 3-histidine (3His) facial triad found recently in the active sites of certain nonheme iron dioxygenases. Three of the reported complexes are designed to serve as convenient precursors to species that model the enzyme–substrate intermediates of 3His dioxygenases; thus, each contains an [Fe(κ3-TIP)]2+ unit in which the remaining coordination sites are occupied by easily displaced ligands, such as solvent molecules and/or carboxylate groups. The viability of these complexes as precursors was demonstrated through the synthesis of TIP-based complexes with β-diketonate and salicylate ligands that represent faithful models of β-diketone dioxygenase and salicylate 1,2-dioxygenase, respectively
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