74 results on '"Dimitrova Y"'
Search Results
2. Quantification of serum gp210 and sp100 antibodies in diagnosis of primary biliary cholangitis
- Author
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Mitova, T., Dimitrova, Y., Manolov, V., Vasilev, V., Popovska, T., Yunchova, V., Gerganov, M., Dimitrov, V., and Angelov, T.
- Published
- 2024
- Full Text
- View/download PDF
3. Cardiac vagal tone, a non‐invasive measure of parasympathetic tone, is a clinically relevant tool in Type 1 diabetes mellitus
- Author
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Brock, C., Jessen, N., Brock, B., Jakobsen, P. E., Hansen, T. K., Rantanen, J. M., Riahi, S., Dimitrova, Y. K., Dons‐Jensen, A., Aziz, Q., Drewes, A. M., and Farmer, A. D.
- Published
- 2017
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- View/download PDF
4. Effects of statins on adhesion molecule expression in endothelial cells
- Author
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Dimitrova, Y., Dunoyer-Geindre, S., Reber, G., Mach, F., Kruithof, E.K.O., and De Moerloose, P.
- Published
- 2003
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5. Theoretical study of the stability of hydrogen-bonded complexes of nitric acid with various bases
- Author
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Dimitrova, Y
- Published
- 2000
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6. Ab initio prediction of the vibrational spectra of hydrogen-bonded complexes PhOH⋯(H2O)2
- Author
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Dimitrova, Y
- Published
- 2000
- Full Text
- View/download PDF
7. Cardiac vagal tone, a non-invasive measure of parasympathetic tone, is a clinically relevant tool in Type 1 diabetes mellitus
- Author
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Brock, C, Jessen, N, Brock, B, Jakobsen, P E, Hansen, T K, Rantanen, J M, Riahi, S, Dimitrova, Y K, Dons-Jensen, A, Aziz, Q, Drewes, A M, Farmer, A D, Brock, C, Jessen, N, Brock, B, Jakobsen, P E, Hansen, T K, Rantanen, J M, Riahi, S, Dimitrova, Y K, Dons-Jensen, A, Aziz, Q, Drewes, A M, and Farmer, A D
- Abstract
AIMS: To compare a novel index of parasympathetic tone, cardiac vagal tone, with established autonomic variables and to test the hypotheses that (1) cardiac vagal tone would be associated with established time and frequency domain measures of heart rate and (2) cardiac vagal tone would be lower in people with Type 1 diabetes than in a matched healthy cohort and lower still in people with established neuropathy.METHODS: Cardiac vagal tone is a validated cardiometrically derived index of parasympathetic tone. It is measured using a standard three-lead electrocardiogram which connects, via Bluetooth, to a smartphone application. A 5-min resting recording of cardiac vagal tone was undertaken and observational comparisons were made between 42 people with Type 1 diabetes and peripheral neuropathy and 23 without peripheral neuropathy and 65 healthy people. In those with neuropathy, 24-h heart rate variability values were compared with cardiac vagal tone. Correlations between cardiac vagal tone and clinical variables were also made.RESULTS: Cardiac vagal tone was lower in people with established neuropathy and Type 1 diabetes in comparison with healthy participants [median (interquartile range) linear vagal scale 3.4 (1.6-5.5 vs 7.0 (5.5-9.6); P < 0.0001]. Cardiac vagal tone was positively associated with time (r = 0.8, P < 0.0001) and frequency domain markers of heart rate variability (r = 0.75, P < 0.0001), representing established measures of parasympathetic function. Cardiac vagal tone was negatively associated with age (r=-0.32, P = 0.003), disease duration (r=-0.43, P < 0.0001) and cardiovascular risk score (r=-0.32, P = 0.006).CONCLUSIONS: Cardiac vagal tone represents a convenient, clinically relevant method of assessing parasympathetic nervous system tone, potentially facilitating the earlier identification of people with Type 1 diabetes who should undergo formal autonomic function testing.
- Published
- 2017
8. Cyclophyllidea van Beneden in Braun, 1900
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Caira, JN, Jensen, K, Mariaux, J, Tkach, VV, Vasileva, GP, Waeschenbach, A, Beveridge, I, Dimitrova, Y, Haukisalmi, V, Greiman, SE, Littlewood, DT, Makarikov, AA, Phillips, AJ, Razafiarisolo, T, Widmer, V, Georgiev, BB, Caira, JN, Jensen, K, Mariaux, J, Tkach, VV, Vasileva, GP, Waeschenbach, A, Beveridge, I, Dimitrova, Y, Haukisalmi, V, Greiman, SE, Littlewood, DT, Makarikov, AA, Phillips, AJ, Razafiarisolo, T, Widmer, V, and Georgiev, BB
- Published
- 2017
9. Heterosis manifestations by survival and larval duration of F1 Bombyx mori L. hybrids
- Author
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Guncheva, R., Panayotov, M., Tsenov, P., and Dimitrova, Y.
- Subjects
hybrids ,Bombyx mori L ,artificial food ,heterosis ,survival ,receptivity - Abstract
The aim of this paper was to study the influence of the degree of heterosis (compared to higher parent value- HP and mean parental values- MP) on the signs, survival and duration of development in F1 hybrids of Bombyx mori L. from different geographical origin, fed by artificial diet. The study was conducted at the Training Experimental Station of the Sericulture section of the Faculty of Agriculture at Trakia University. A total of 10 hybrids were tested featuring 6 breeds from the genetic bank of Sericulture and Agriculture Experiment Station (SAES)-Vratsa. Silkworms were reared with artificial diet containing 15% powder of dried mulberry leaf produced at SAES-Vratsa and prepared by methods, developed by the manufacturer, whereby 250g of dry substance and 675ml of distilled water are homogenized using a mixer. The mixture is cured thermally in a microwave for 10min. at ~800W. The receptivity of specimens was determined based on the results from the survival and the duration in the I-st age of the larval stage. In heterogeneous crossbreds higher survival rate in the first age is exhibited by hybrids in which a Japanese type breed was used as dam. Homogeneous crossbreds created with the participation of Japanese breeds excel in both analyzed traits those involving a Chinese type. For the survival trait heterosis manifestations to higher parent value (HP) and mean parental values (MP), were detected in the majority of hybrids (90.91%). Regarding the duration of development, heterosis effect to MP was observed in all F1 hybrids, while to HP heterosis is exhibited by 60% of the tested F1 hybrids.
- Published
- 2016
10. Structure of the MIND Complex Shows a Regulatory Focus of Yeast Kinetochore Assembly
- Author
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Dimitrova, Y., primary, Jenni, S., additional, Valverde, R., additional, Khin, Y., additional, and Harrison, S.C., additional
- Published
- 2016
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11. Structure of the MIND Complex Shows a Regulatory Focus of Yeast Kinetochore Assembly
- Author
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Valverde, R., primary, Jenni, S., additional, Dimitrova, Y., additional, Khin, Y., additional, and Harrison, S.C., additional
- Published
- 2016
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12. Heterosis manifestations by survival and larval duration of F Bombyx mori L. Hybrids reared 1 with artificial diet
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Guncheva, R., primary, Panayotov, M., additional, Tsenov, P., additional, and Dimitrova, Y., additional
- Published
- 2016
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13. The karyotype of four Trichinella species
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Mutafova, T., Dimitrova, Y., and Komandarev, S.
- Published
- 1982
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14. Hémostase. Le point sur les nouveaux antithrombotiques
- Author
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Boehlen, Françoise, Tirefort-Dimitrova, Y., De Moerloose, Philippe, and Fontana, Pierre
- Subjects
ddc:616 ,Anticoagulants/*pharmacology ,Clinical Trials as Topic ,Thrombosis/*prevention & control ,Humans ,Platelet Aggregation Inhibitors/*pharmacology - Abstract
Update on new antithrombotic treatments Antithrombotic treatments are frequently prescribed in different clinical situations. Classical anticoagulants have some disadvantages. New anticoagulants have emerged recently. Fondaparinux is now prescribed for both prophylaxis and treatment of venous thromboembolism. Two drugs are particularly interesting: rivaroxaban and dabigatran. Concerning the new antiplatelet agents, many molecules such as prasugrel, ticagrelor, cangrelor, SCH530348 or terutroban have appeared recently. They are directed either to the P2Y12 receptor or to other original targets. Studies have shown an increased bleeding risk for some of them as well as unexpected side effects. In the next future, these new molecules could allow a more individualised prescription of antithrombotic agents.
- Published
- 2010
15. Lightness estimation errors in a 3D context
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Dimitrova, Y., primary, McOwan, P., additional, and Johnston, A., additional
- Published
- 2010
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16. Quantum - Chemical Study of the Relation Between Electronic Structure and IR Spectra of Neutral Molecules, Anion - Radicals, and Dianions of Aromatic Nitriles
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Dimitrova, Y., primary and Juchnovski, I., additional
- Published
- 1995
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17. Ab initio study of the vibrational spectra of the hydrogen-bonded nitric acid dimer
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Dimitrova, Y.
- Published
- 2001
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18. Ab initio study of structures of hydrogen-bonded nitric acid complexes
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Dimitrova, Y. and Peyerimhoff, S.
- Published
- 2000
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19. Solvent effects on vibrational spectrum of hydrogen-bonded complex PhOH H~2O. An ab initio study
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Dimitrova, Y.
- Published
- 1999
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20. Ab initio prediction of the vibrational spectrum of the hydrogen-bonded compex H~2CO...HOCN
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Dimitrova, Y.
- Published
- 1998
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21. Vibrational spectrum of the hydrogen-bonded complex H~2CO...HOCH6-point double bondNH: an ab initio study
- Author
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Dimitrova, Y. and Stamboliyska, B. A.
- Published
- 1998
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22. [Update on new antithrombotic treatments]
- Author
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Boehlen F, Tirefort-Dimitrova Y, de Moerloose P, and Pierre Fontana
- Subjects
Clinical Trials as Topic ,Anticoagulants ,Humans ,Thrombosis ,Platelet Aggregation Inhibitors - Abstract
Update on new antithrombotic treatments Antithrombotic treatments are frequently prescribed in different clinical situations. Classical anticoagulants have some disadvantages. New anticoagulants have emerged recently. Fondaparinux is now prescribed for both prophylaxis and treatment of venous thromboembolism. Two drugs are particularly interesting: rivaroxaban and dabigatran. Concerning the new antiplatelet agents, many molecules such as prasugrel, ticagrelor, cangrelor, SCH530348 or terutroban have appeared recently. They are directed either to the P2Y12 receptor or to other original targets. Studies have shown an increased bleeding risk for some of them as well as unexpected side effects. In the next future, these new molecules could allow a more individualised prescription of antithrombotic agents.
23. Theoretical study of the n->p^* transitions in hydrogen-bonded formaldehyde complexes
- Author
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Dimitrova, Y. and Peyerimhoff, S. D.
- Published
- 1994
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24. Exploration, expansion and definition of the atropopeptide family of ribosomally synthesized and posttranslationally modified peptides.
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Biermann F, Tan B, Breitenbach M, Kakumu Y, Nanudorn P, Dimitrova Y, Walker AS, Ueoka R, and Helfrich EJN
- Abstract
Ribosomally synthesized and posttranslationally modified peptides (RiPPs) constitute a diverse class of natural products. Atropopeptides are a recent addition to the class. Here we developed AtropoFinder, a genome mining algorithm to chart the biosynthetic landscape of the atropopeptides. AtropoFinder identified more than 650 atropopeptide biosynthetic gene clusters (BGCs). We pinpointed crucial motifs and residues in leader and core peptide sequences, prompting a refined definition of the atropopeptide RiPP family. Our study revealed that a substantial subset of atropopeptide BGCs harbors multiple tailoring genes, thus suggesting a broader structural diversity than previously anticipated. To verify AtropoFinder, we heterologously expressed four atropopeptide BGCs, which resulted in the identification of novel atropopeptides with varying peptide lengths, number and types of modifications. Atropopeptides serve as a proof-of-principle for the versatile genome mining approach developed in this study that can be repurposed for the identification of RiPP and other BGCs that currently evade detection., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)
- Published
- 2024
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25. Investigation of the Sensing Properties of Lanthanoid Metal-Organic Frameworks (Ln-MOFs) with Terephthalic Acid.
- Author
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Elenkova D, Dimitrova Y, Tsvetkov M, Morgenstern B, Milanova M, Todorovsky D, and Zaharieva J
- Abstract
The solvothermal synthesis of LnCl
3 . nH2 O with terephthalic acid (benzene-1,4-dicarboxylic acid, H2 BDC) produced metal-organic frameworks (LnBDC), [Ln2 (BDC)3 (H2 O)4 ]∞ , where Ln = Sm, Eu, Tb, and Dy. The materials obtained were characterized by a number of physico-chemical techniques. The influence of the ionic radius of the lanthanides on the microstructural characteristics of the Ln-MOFs was evaluated by performing Rietveld refinement. The MOFs obtained were tested as fluorescent sensors for numerous cations and anions in water. The highly luminescent EuBDC and TbBDC demonstrated multi-responsive luminescence sensing functions to detect Ag(I), Fe(III), Cr(III), and Cr(VI), which are essential for their environmental applications. By applying the non-linear Stern-Volmer equation, the fluorescent quenching mechanism was determined. The stability of the obtained materials in water in a wide pH range (acidity pH = 4 and alkalinity pH = 9 solutions) was confirmed.- Published
- 2024
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26. Cystine-knot peptide inhibitors of HTRA1 bind to a cryptic pocket within the active site region.
- Author
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Li Y, Wei Y, Ultsch M, Li W, Tang W, Tombling B, Gao X, Dimitrova Y, Gampe C, Fuhrmann J, Zhang Y, Hannoush RN, and Kirchhofer D
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- Humans, Peptide Library, Crystallography, X-Ray, Protein Binding, Cystine chemistry, Cystine metabolism, Models, Molecular, High-Temperature Requirement A Serine Peptidase 1 metabolism, High-Temperature Requirement A Serine Peptidase 1 genetics, Catalytic Domain, Peptides chemistry, Peptides metabolism, Peptides pharmacology
- Abstract
Cystine-knot peptides (CKPs) are naturally occurring peptides that exhibit exceptional chemical and proteolytic stability. We leveraged the CKP carboxypeptidase A1 inhibitor as a scaffold to construct phage-displayed CKP libraries and subsequently screened these collections against HTRA1, a trimeric serine protease implicated in age-related macular degeneration and osteoarthritis. The initial hits were optimized by using affinity maturation strategies to yield highly selective and potent picomolar inhibitors of HTRA1. Crystal structures, coupled with biochemical studies, reveal that the CKPs do not interact in a substrate-like manner but bind to a cryptic pocket at the S1' site region of HTRA1 and abolish catalysis by stabilizing a non-competent active site conformation. The opening and closing of this cryptic pocket is controlled by the gatekeeper residue V221, and its movement is facilitated by the absence of a constraining disulfide bond that is typically present in trypsin fold serine proteases, thereby explaining the remarkable selectivity of the CKPs. Our findings reveal an intriguing mechanism for modulating the activity of HTRA1, and highlight the utility of CKP-based phage display platforms in uncovering potent and selective inhibitors against challenging therapeutic targets., (© 2024. The Author(s).)
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- 2024
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27. Adynamic response to cold pain reflects dysautonomia in type 1 diabetes and polyneuropathy.
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Arendt Nielsen T, Lundbye-Christensen S, Krasimirova Dimitrova Y, Riahi S, Brock B, Mohr Drewes A, and Brock C
- Subjects
- Humans, Autonomic Nervous System physiology, Heart, Heart Rate physiology, Diabetes Mellitus, Type 1 complications, Primary Dysautonomias etiology, Polyneuropathies
- Abstract
Cardiac autonomic neuropathy (CAN), widely assessed by heart rate variability (HRV), is a common complication of long-term diabetes. We hypothesized that HRV dynamics during tonic cold pain in individuals with type 1 diabetes mellitus (T1DM) could potentially demask CAN. Forty-eight individuals with long-term T1DM and distal symmetrical polyneuropathy and 21 healthy controls were included. HRV measures were retrieved from 24-h electrocardiograms. Moreover, ultra-short-term HRV recordings were used to assess the dynamic response to the immersion of the hand into 2 °C cold water for 120 s. Compared to healthy, the T1DM group had expectedly lower 24-h HRV measures for most components (p < 0.01), indicating dysautonomia. In the T1DM group, exposure to cold pain caused diminished sympathetic (p < 0.001) and adynamic parasympathetic (p < 0.01) HRV responses. Furthermore, compared to healthy, cold pain exposure caused lower parasympathetic (RMSSD: 4% vs. 20%; p = 0.002) and sympathetic responses (LF: 11% vs. 73%; p = 0.044) in the T1MD group. QRISK3-scores are negatively correlated with HRV measures in 24-h and ultra-short-term recordings. In T1DM, an attenuated sympathovagal response was shown as convincingly adynamic parasympathetic responses and diminished sympathetic adaptability, causing chronometric heart rhythm and rigid neurocardiac regulation threatening homeostasis. The findings associate with an increased risk of cardiovascular disease, emphasizing clinical relevance., (© 2023. The Author(s).)
- Published
- 2023
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28. Cellular, Antibody and Cytokine Pathways in Children with Acute SARS-CoV-2 Infection and MIS-C-Can We Match the Puzzle?
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Lazova S, Dimitrova Y, Hristova D, Tzotcheva I, and Velikova T
- Abstract
The newly identified strain of the Coronaviridae family called severe acute respiratory syndrome (SARS-CoV-2) recently became the most significant health threat for adults and children. Some main predictors of severe clinical course in patients with SARS-CoV-2 infection are age and concomitant health conditions. Therefore, the proper evaluation of SARS-CoV-2-specific immunity is urgently required to understand and predict the spectrum of possible clinical phenotypes and recommend vaccination options and regimens in children. Furthermore, it is critical to characterize the nature of SARS-CoV-2-specific immune responses in children following asymptomatic infection and COVID-19 and other related conditions such as multisystem inflammatory syndrome (MIS-C), para-infectious and late postinfectious consequences. Recent studies involving children revealed a variety of cytokines, T cells and antibody responses in the pathogenesis of the disease. Moreover, different clinical scenarios in children were observed-asymptomatic seroprevalence, acute SARS-CoV-2 infection, and rarely severe COVID-19 with typical cytokine storm, MIS-C, long COVID-19, etc. Therefore, to gain a better clinical view, adequate diagnostic criteria and treatment algorithms, it is essential to create a realistic picture of the immunological puzzle of SARS-CoV-2 infection in different age groups. Finally, it was demonstrated that children may exert a potent and prolonged adaptive anti-SARS-CoV-2 immune response, with significant cross-reactions against other human Corona Viruses, that might contribute to disease sparing effect in this age range. However, the immunopathology of the virus has to be elucidated first.
- Published
- 2022
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29. Luminescent Complexes of Europium (III) with 2-(Phenylethynyl)-1,10-phenanthroline: The Role of the Counterions.
- Author
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Elenkova D, Lyapchev R, Romanova J, Morgenstern B, Dimitrova Y, Dimov D, Tsvetkov M, and Zaharieva J
- Abstract
New antenna ligand, 2-(phenylethynyl)-1,10-phenanthroline (PEP), and its luminescent Eu (III) complexes, Eu(PEP)
2 Cl3 and Eu(PEP)2 (NO3 )3 , are synthesized and characterized. The synthetic procedure applied is based on reacting of europium salts with ligand in hot acetonitrile solutions in molar ratio 1 to 2. The structure of the complexes is refined by X-ray diffraction based on the single crystals obtained. The compounds [Eu(PEP)2 Cl3 ]·2CH3 CN and [Eu(PEP)2 (NO3 )3 ]∙2CH3 CN crystalize in monoclinic space group P21/n and P21/c , respectively, with two acetonitrile solvent molecules. Intra- and inter-ligand π-π stacking interactions are present in solid stat and are realized between the phenanthroline moieties, as well as between the substituents and the phenanthroline units. The optical properties of the complexes are investigated in solid state, acetonitrile and dichloromethane solution. Both compounds exhibit bright red luminescence caused by the organic ligand acting as antenna for sensitization of Eu (III) emission. The newly designed complexes differ in counter ions in the inner coordination sphere, which allows exploring their influence on the stability, molecular and supramolecular structure, fluorescent properties and symmetry of the Eu (III) ion. In addition, molecular simulations are performed in order to explain the observed experimental behavior of the complexes. The discovered structure-properties relationships give insight on the role of the counter ions in the molecular design of new Eu (III) based luminescent materials.- Published
- 2021
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30. Seeing is believing: our evolving view of kinetochore structure, composition, and assembly.
- Author
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Hamilton G, Dimitrova Y, and Davis TN
- Subjects
- Animals, Cell Cycle, Humans, Models, Biological, Models, Molecular, Saccharomyces cerevisiae Proteins metabolism, Saccharomycetales metabolism, Kinetochores metabolism
- Abstract
This review highlights three recent trends in the field of kinetochore biology: the proliferation of structural data for kinetochore protein complexes (including CBF3, Dam1c, Mis12c
MIND , and CENP-NLChl4/Iml3 ); the growing consensus that the kinetochore is a dynamic structure whose composition changes as the cell cycle progresses; and the mounting evidence of multiple pathways whereby the microtubule-binding elements of the outer kinetochore may be recruited by inner kinetochore proteins. Our focus is on the two best-studied systems in the field: human and budding yeast kinetochores. This review will demonstrate the remarkable similarity of these two systems, as well as their intriguing differences., (Copyright © 2019 Elsevier Ltd. All rights reserved.)- Published
- 2019
- Full Text
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31. TFAP2A is a component of the ZEB1/2 network that regulates TGFB1-induced epithelial to mesenchymal transition.
- Author
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Dimitrova Y, Gruber AJ, Mittal N, Ghosh S, Dimitriades B, Mathow D, Grandy WA, Christofori G, and Zavolan M
- Subjects
- Animals, Cell Line, Female, Homeodomain Proteins metabolism, Humans, Mammary Glands, Animal metabolism, Mammary Glands, Animal physiopathology, Mice, Repressor Proteins metabolism, Transcription Factor AP-2 genetics, Transforming Growth Factor beta1 genetics, Transforming Growth Factor beta1 metabolism, Zinc Finger E-box Binding Homeobox 2, Zinc Finger E-box-Binding Homeobox 1 metabolism, Epithelial-Mesenchymal Transition genetics, Gene Expression Regulation, Neoplastic, Homeodomain Proteins genetics, Repressor Proteins genetics, Transcription Factor AP-2 metabolism, Zinc Finger E-box-Binding Homeobox 1 genetics
- Abstract
Background: The transition between epithelial and mesenchymal phenotypes (EMT) occurs in a variety of contexts. It is critical for mammalian development and it is also involved in tumor initiation and progression. Master transcription factor (TF) regulators of this process are conserved between mouse and human., Methods: From a computational analysis of a variety of high-throughput sequencing data sets we initially inferred that TFAP2A is connected to the core EMT network in both species. We then analysed publicly available human breast cancer data for TFAP2A expression and also studied the expression (by mRNA sequencing), activity (by monitoring the expression of its predicted targets), and binding (by electrophoretic mobility shift assay and chromatin immunoprecipitation) of this factor in a mouse mammary gland EMT model system (NMuMG) cell line., Results: We found that upon induction of EMT, the activity of TFAP2A, reflected in the expression level of its predicted targets, is up-regulated in a variety of systems, both murine and human, while TFAP2A's expression is increased in more "stem-like" cancers. We provide strong evidence for the direct interaction between the TFAP2A TF and the ZEB2 promoter and we demonstrate that this interaction affects ZEB2 expression. Overexpression of TFAP2A from an exogenous construct perturbs EMT, however, in a manner similar to the downregulation of endogenous TFAP2A that takes place during EMT., Conclusions: Our study reveals that TFAP2A is a conserved component of the core network that regulates EMT, acting as a repressor of many genes, including ZEB2., Reviewers: This article has been reviewed by Dr. Martijn Huynen and Dr. Nicola Aceto.
- Published
- 2017
- Full Text
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32. Study of the Microbiological Quality of Bulgarian Bottled Water in Terms of Its Contamination with Pseudomonas Aeruginosa.
- Author
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Georgieva V and Dimitrova Y
- Subjects
- Anti-Bacterial Agents pharmacology, Bulgaria, Colony Count, Microbial, Drug Resistance, Bacterial, Humans, Microbial Sensitivity Tests, Pseudomonas aeruginosa drug effects, Drinking Water microbiology, Pseudomonas aeruginosa isolation & purification
- Abstract
Background: Due to the widespread use of bottled water, it is important from a hygienic point of view to ensure that these products have good quality and meet the requirements set out in regulations., Methods and Results: In the period 2000-2013, a large-scale study (2,500 samples) was carried out on the quality of Bulgarian bottled water as per the microbiological parameters laid down in the European and Bulgarian legislation. Standard microbiological methods were applied. There is strong evidence that the most frequently isolated contaminant in these products was Pseudomonas aeruginosa. This agent was found in 274 samples out of a total of 2,500 analysed bottled waters. Because of the absolute prohibition of the presence of this microorganism in the finished product, the manufacturers should not allow their products with compromised quality to reach the market. They are obliged to check the quality of each batch by conducting an internal monitoring of production. When any inconsistencies are established in microbiological parameters, the producers must detect the critical point and apply more effective decontamination measures of the bottling lines. Given the importance of this fact for the health of consumers, the study also included determination of the antimicrobial resistance of P. aeruginosa strains isolated from Bulgarian bottled water. Ten strains of P. aeruginosa, isolated from bottled water and other water habitats in the environment, were tested for the effect of 13 antimicrobial agents by applying the Kirby-Bauer's method., Conclusions: The investigation found that Pseudomonas aeruginosa strains isolated from bottled water are sensitive to Ceftazidime, Amikacin, Ciprofloxacin, and Cefepime and one of them is resistant to Meropenem and Piperacillin. Another important conclusion is that there is no specific behaviour of P. aeruginosa strains originating from different sources to the test antimicrobials. The authors consider that drinking tap water is perhaps a more appropriate way for newborns, infants, elderly, and people with compromised immunity to satisfy thirst than using bottled water., (Copyright© by the National Institute of Public Health, Prague 2016)
- Published
- 2016
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33. Electron paramagnetic resonance spectroscopy in radiation research: Current status and perspectives.
- Author
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Rana S, Chawla R, Kumar R, Singh S, Zheleva A, Dimitrova Y, Gadjeva V, Arora R, Sultana S, and Sharma RK
- Abstract
Exposure to radiation leads to a number of health-related malfunctions. Ionizing radiation is more harmful than non-ionizing radiation, as it causes both direct and indirect effects. Irradiation with ionizing radiation results in free radical-induced oxidative stress. Free radical-mediated oxidative stress has been implicated in a plethora of diseased states, including cancer, arthritis, aging, Parkinson's disease, and so on. Electron Paramagnetic Resonance (EPR) spectroscopy has various applications to measure free radicals, in radiation research. Free radicals disintegrate immediately in aqueous environment. Free radicals can be detected indirectly by the EPR spin trapping technique in which these forms stabilize the radical adduct and produce characteristic EPR spectra for specific radicals. Ionizing radiation-induced free radicals in calcified tissues, for example, teeth, bone, and fingernail, can be detected directly by EPR spectroscopy, due to their extended stability. Various applications of EPR in radiation research studies are discussed in this review.
- Published
- 2010
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34. [Antiphospholipid syndrome: much new data].
- Author
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de Moerloose P, Tirefort-Dimitrova Y, Noger F, Spycher-Elbes R, and Boehlen F
- Subjects
- Antibodies, Anticardiolipin blood, Antiphospholipid Syndrome immunology, Antiphospholipid Syndrome therapy, Child, Female, Humans, Pregnancy, Pregnancy Complications blood, Pregnancy Complications immunology, Pregnancy Complications therapy, Registries, Switzerland, beta 2-Glycoprotein I blood, Antiphospholipid Syndrome blood
- Abstract
Recently some key papers and consensus have shed some new light on antiphospholipid syndrome (APS). Concerning the tests the search for lupus anticoagulant is now better defined. A modified antibeta2-glycoprotein I assay has been shown to be more specific for clinical complications. It seems necessary to still perform anticardiolipin antibodies in case of pregnancy morbidity but not in case of thrombosis which raises the question of two separate clinical entities with different pathologic mechanisms. Concerning the pathophysiology, new data emphasize the role of complement and underscore the role of genetic predisposition. The data of some large cohort followed prospectively such as the European cohort (1000 APS patients) as well the data of some registries (APS in children and patients with a catastrophic APS) bring some new important information on the clinical aspects of the syndrome. Finally this review will propose some algorithms to treat patients with APS.
- Published
- 2010
35. [Update on new antithrombotic treatments].
- Author
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Boehlen F, Tirefort-Dimitrova Y, de Moerloose P, and Fontana P
- Subjects
- Clinical Trials as Topic, Humans, Anticoagulants pharmacology, Platelet Aggregation Inhibitors pharmacology, Thrombosis prevention & control
- Abstract
Update on new antithrombotic treatments Antithrombotic treatments are frequently prescribed in different clinical situations. Classical anticoagulants have some disadvantages. New anticoagulants have emerged recently. Fondaparinux is now prescribed for both prophylaxis and treatment of venous thromboembolism. Two drugs are particularly interesting: rivaroxaban and dabigatran. Concerning the new antiplatelet agents, many molecules such as prasugrel, ticagrelor, cangrelor, SCH530348 or terutroban have appeared recently. They are directed either to the P2Y12 receptor or to other original targets. Studies have shown an increased bleeding risk for some of them as well as unexpected side effects. In the next future, these new molecules could allow a more individualised prescription of antithrombotic agents.
- Published
- 2010
36. Theoretical study of the vibrational spectra of the hydrogen-bonded systems between pyridine-3-carboxamide (nicotinamide) and DMSO.
- Author
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Dimitrova Y and Daskalova LI
- Subjects
- Computer Simulation, Dimethyl Sulfoxide metabolism, Hydrogen Bonding, Models, Molecular, Niacinamide metabolism, Spectrum Analysis, Vibration, Dimethyl Sulfoxide chemistry, Models, Theoretical, Niacinamide chemistry
- Abstract
The vibrational characteristics (vibrational frequencies and infrared intensities) for the hydrogen-bonded systems of nicotinamide (NA(Z) and NA(E)) with dimethyl sulfoxide (DMSO) have been predicted using ab initio SCF/6-31G(d,p) and DFT (BLYP/6-311++G(d,p)) calculations. The changes in the vibrational characteristics from free monomers to a complex have been calculated. The ab initio and BLYP calculations show that the complexation between nicotinamide (NA(Z) and NA(E)) and DMSO leads to large red shifts of the stretching vibrations for the hydrogen-bonded N-H bonds of nicotinamide and very strong increase in their IR intensity. The results from the BLYP/6-311++G(d,p) calculations show that the predicted red shifts of the nu(s)(NH) and nu(as)(NH) vibrations for the complex NA(E)-DMSO (1:2) (Deltanu(as)(NH)=-186 cm(-1) and Deltanu(s)(NH)=-198 cm(-1)) are in better agreement with the experimentally measured. The magnitudes of the wavenumber shifts are indicative of strong NH...O hydrogen-bonded interactions in both complexes. The calculations predict an increase of the IR intensity of nu(s)(NH) and nu(as)(NH) vibrations in the complexes up to 14 times. Having in mind that in more cases the predicted changes in the vibrational characteristics for the complexes studied are very near, it could be concluded that both conformers of nicotinamide, Z-conformer and E-conformer, are present in the solution forming the hydrogen-bonded complexes with DMSO.
- Published
- 2009
- Full Text
- View/download PDF
37. Structure and vibrational spectrum of the hydrogen-bonded system between 4-tert-butylphenol and N-bases: Ab initio and DFT studies.
- Author
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Dimitrova Y
- Subjects
- Computer Simulation, Hydrogen Bonding, Models, Molecular, Spectrum Analysis, Phenols chemistry, Vibration
- Abstract
The structural and vibrational characteristics of the hydrogen-bonded system between 1,5,7-triazabicyclo [4.4.0] dec-5-ene (TBD) and 4-tert-butylphenol have been investigated employing ab initio and DFT calculations at different basis sets. The calculations show that the optimized structure of the studied system is cyclic. The corrected values of the dissociation energy for the hydrogen-bonded complex have been calculated in order to estimate its stability. The influence of the hydrogen bonding on the properties of the monomers (TBD and 4-tert-butylphenol) has been investigated. The hydrogen bonding between TBD and 4-tert-butylphenol leads to changes in the structural (bond lengths and angles) and vibrational (vibrational frequencies and infrared intensities) characteristics of the monomers. It was established that the TBD molecule is considerably deformed upon hydrogen bonding, while the deformation of the 4-t-BuPhOH is smaller. In agreement with the experiment, the calculations show that the stretching O-H vibration from 4-tert-butylphenol is shifted to lower frequency upon hydrogen bonding. The predicted frequency shift Deltanu(O-H) (-338cm(-1)) is in very good agreement with the experimentally observed (-351cm(-1)). In the same time the IR intensity of the nu(O-H) increases dramatically in the hydrogen-bonded system.
- Published
- 2008
- Full Text
- View/download PDF
38. Theoretical study of the structures and vibrational spectra of the hydrogen-bonded systems of 4-cyanophenol with N-bases.
- Author
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Dimitrova Y and Tsenov JA
- Subjects
- Hydrogen Bonding, Thermodynamics, Models, Chemical, Nitrogen chemistry, Phenols chemistry, Vibration
- Abstract
The structural and vibrational features of the hydrogen bonded complexes of 1,5,7-triazabicyclo [4.4.0] dec-5-ene (TBD) with one and two 4-CNPhOH molecules have been studied extensively by ab initio SCF/6-31G(d,p) and BLYP calculations with various basis sets: 6-31G(d,p), 6-31+G(d,p) and 6-31++G(d,p). Full geometry optimization was made for the complexes studied. The nature of the hydrogen bonding and the influence of the hydrogen bonding on the structural and vibrational characteristics of the monomers have been investigated. The corrected values of the dissociation energy for the hydrogen-bonded complexes have been calculated in order to estimate their stability. The calculated values of the dissociation energy per phenol molecule indicate that the complex: TBD: 4-CNPhOH (1:1) is more stable than the complex: TBD: 4-CNPhOH (1:2). The changes in the structural and vibrational characteristics upon hydrogen bonding depend on the strength of the hydrogen bonds. In agreement with the experiment, the calculations show that the complexation between TBD and 4-CNPhOH leads to considerably changes in the vibrational characteristics of the stretching O-H vibration. The vibrational frequency of the O-H stretching vibration is shifted to lower wave numbers upon hydrogen bonding. The predicted frequency shifts Deltanu(O-H) for the complexes--TBD: 4-CNPhOH (1:1) and TBD: 4-CNPhOH (1:2) are in the range from -190 cm(-1) to -586 cm(-1). In the same time the IR intensity of the O-H stretching vibration increases dramatically in the hydrogen-bonded complexes.
- Published
- 2007
- Full Text
- View/download PDF
39. Hydrogen-bonded complexes of nitrous and nitric acids with ethene Ab initio and DFT studies.
- Author
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Dimitrova Y
- Subjects
- Ethylenes metabolism, Hydrogen Bonding, Molecular Structure, Nitric Acid metabolism, Nitrous Acid metabolism, Ethylenes chemistry, Nitric Acid chemistry, Nitrous Acid chemistry
- Abstract
The complexes formed by ethene with nitric and nitrous (trans and cis) acids have been investigated by ab initio (SCF and MP2) and B3LYP calculations with 6-311++G(d,p) basis set. Full geometry optimisation has been performed for the complexes studied. The most stable structures of the complexes are established. Bearing in mind the corrected values of the dissociation energy the studied hydrogen-bonded complexes can be ordered as follows: C(2)H(4)...HONO(2)>C(2)H(4)...HONO-trans>C(2)H(4)...HONO-cis. In the complexes the acids act as proton donors forming the pi-type of hydrogen bond with ethene. The predicted changes in the vibrational characteristics (vibrational frequencies and infrared intensities) arising from the hydrogen bonding are in good agreement with the experimentally measured. The predicted frequency shift of the stretching OH vibration in the nitric acid is largest (-210 cm(-1)), followed by the shifts in the trans-HONO (-141 cm(-1)) and cis-HONO (-109 cm(-1)). The calculations predict an increase of the IR intensity of the stretching O-H vibration in the complexes from 6 to 10 times.
- Published
- 2007
- Full Text
- View/download PDF
40. Comparative study of the hydrogen-bonded complexes of phenol and o-cyanophenol with CO Ab initio and DFT approachs.
- Author
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Dimitrova Y and Daskalova LI
- Subjects
- Hydrogen Bonding, Carbon Monoxide chemistry, Models, Molecular, Nitriles chemistry, Phenol chemistry
- Abstract
The structures, stability and vibrational spectra of the hydrogen-bonded complexes of carbon monoxide (CO) with phenol and o-cyanophenol (syn and anti) have been studied using ab initio and DFT calculations. Full geometry optimization has been performed for the studied complexes by DFT (BLYP/6-311++G(d,p)) calculations. The calculations show that the hydrogen-bond formation of carbon monoxide (CO) with phenol and o-cyanophenol (syn and anti) leads to the following stable structures: C6H5OH...CO (1A); C6H5OH...OC (1B); (syn) o-CNC6H4OH...CO (2A-syn); (syn) o-CNC6H4OH...OC (2B-syn); (anti) o-CNC6H4 OH...CO (2A-anti) and (anti) o-CNC6H4OH...OC (2B-anti). Having in mind the corrected values of the dissociation energy, the studied hydrogen-bonded complexes can be ordered according their stability as follows: 2A-anti>2A-syn>1A>2B-anti>1B>2B-syn. The predicted red-shifts for the nuOH vibration with the B3LYP/6-311++G(d,p) calculations for the structures 1A (-46 cm-1), 2A-syn (-60 cm-1) and 2A-anti (-73 cm-1) are in very good agreement with the experimentally observed. The magnitudes of the wavenumber shifts are indicative of relatively weak OH...C hydrogen-bonded interactions. The calculations predict an increase of the IR intensity of the nuOH vibration in the complexes 1A, 2A-anti and 2A-syn up to five times.
- Published
- 2007
- Full Text
- View/download PDF
41. Theoretical study of the changes in the vibrational characteristics arising from the hydrogen bonding between Vitamin C (L-ascorbic acid) and H2O.
- Author
-
Dimitrova Y
- Subjects
- Hydrogen Bonding, Molecular Structure, Ascorbic Acid chemistry, Vibration, Water chemistry
- Abstract
The vibrational characteristics (vibrational frequencies, infrared intensities and Raman activities) for the hydrogen-bonded system of Vitamin C (L-ascorbic acid) with five water molecules have been predicted using ab initio SCF/6-31G(d,p) calculations and DFT (BLYP) calculations with 6-31G(d,p) and 6-31++G(d,p) basis sets. The changes in the vibrational characteristics from free monomers to a complex have been calculated. The ab initio and BLYP calculations show that the complexation between Vitamin C and five water molecules leads to large red shifts of the stretching vibrations for the monomer bonds involved in the hydrogen bonding and very strong increase in their IR intensity. The predicted frequency shifts for the stretching vibrations from Vitamin C taking part in the hydrogen bonding are up to -508 cm(-1). The magnitude of the wavenumber shifts is indicative of relatively strong OH...H hydrogen-bonded interactions. In the same time the IR intensity and Raman activity of these vibrations increase upon complexation. The IR intensity increases dramatically (up to 12 times) and Raman activity increases up to three times. The ab initio and BLYP calculations show, that the symmetric OH vibrations of water molecules are more sensitive to the complexation. The hydrogen bonding leads to very large red shifts of these vibrations and very strong increase in their IR intensity. The asymmetric OH stretching vibrations of water, free from hydrogen bonding are less sensitive to the complexation than the hydrogen-bonded symmetric OH stretching vibrations. The increases of the IR intensities for these vibrations are lower and red shifts are negligible.
- Published
- 2006
- Full Text
- View/download PDF
42. Vibrational frequencies and infrared intensities of the hydrogen-bonded complexes of nitrous acid with ethers: ab initio and DFT studies.
- Author
-
Dimitrova Y and Slavova I
- Subjects
- Hydrogen Bonding, Molecular Structure, Spectrum Analysis, Ethers chemistry, Infrared Rays, Nitrous Acid chemistry, Vibration
- Abstract
The vibrational spectra of the binary complexes formed by HONO-trans and HONO-cis with dimethyl and diethyl ethers have been investigated using ab initio calculations at the SCF and MP2 levels with 6-311++G(d,p) basis set and B3LYP calculations with 6-31G(d,p) and 6-31+G(d,p) basis sets. Full geometry optimisation was made for the complexes studied. The accuracy of the ab initio calculations have been estimated by comparison between the predicted values of the vibrational characteristics (vibrational frequencies and infrared intensities) and the available experimental data. It was established, that the methods, used in this study are well adapted to the problem under examination. The predicted values with the B3LYP calculations are very near to the results, obtained with 6-311++G(d,p)/MP2. The ab initio and DFT calculations show that the changes in the vibrational characteristics (vibrational frequencies and infrared intensities) upon hydrogen bonding for the hydrogen-bonded complex (CH3)2O...HONO-trans are larger than for the complex (CH3)2O...HONO-cis.
- Published
- 2005
- Full Text
- View/download PDF
43. Fluvastatin increases the expression of adhesion molecules, monocyte chemoattractant protein-1 and tissue factor in HUVEC stimulated by patient IgG fractions containing antiphospholipid antibodies.
- Author
-
Dunoyer-Geindre S, Dimitrova Y, Fish RJ, Satta N, Reber G, Kruithof EK, and de Moerloose P
- Subjects
- Adolescent, Adult, Antibodies, Antiphospholipid pharmacology, Cell Adhesion Molecules analysis, Cell Adhesion Molecules drug effects, Cells, Cultured, Chemokine CCL2 analysis, Chemokine CCL2 drug effects, Endothelium, Vascular pathology, Female, Fluvastatin, Gene Expression Regulation drug effects, Humans, Immunoglobulin G pharmacology, Inflammation chemically induced, Inflammation immunology, Male, Middle Aged, Thromboplastin analysis, Thromboplastin drug effects, Umbilical Cord cytology, Antiphospholipid Syndrome pathology, Cell Adhesion Molecules genetics, Chemokine CCL2 genetics, Endothelium, Vascular drug effects, Fatty Acids, Monounsaturated pharmacology, Indoles pharmacology, Thromboplastin genetics
- Abstract
The presence of antiphospholipid antibodies (APLA) is associated with an increased risk of recurrent thrombosis and pregnancy loss. APLA are able to activate endothelial cells (EC) and induce an increase in the expression of inflammatory marker proteins, such as leukocyte adhesion molecules, tissue factor or the monocyte chemoattractant protein-1 (MCP-1). Our objective was to investigate the effect of statins on EC activation induced by APLA in vitro. IgG was purified from the plasma of six patients with APLA and from healthy controls. EC were incubated with patient IgG or with control IgG, in the presence or absence of 5microM of fluvastatin, and expression of the leukocyte adhesion molecules, VCAM-1 and E-selectin, analyzed by flow cytometry and by quantitative reverse transcriptase-PCR (QRT-PCR). The expression of tissue factor and the chemokine MCP-1 was analyzed by QRT-PCR alone. Incubation of EC with patient IgG increased the expression of VCAM-1, E-selectin, tissue factor and MCP-1. Prior treatment of the cells with fluvastatin further increased the expression of these proteins. The fluvastatin effect was reversed by co-incubation with mevalonate or geranylgeranylpyrophosphate and mimicked by the geranylgeranyl transferase inhibitor GGTI-286. Our results show that in cultured human EC, statins increase the extent of inflammatory activation induced by APLA. This effect appears to be mediated by an inhibitory effect of statins on one or more geranylgeranylated protein(s).
- Published
- 2005
- Full Text
- View/download PDF
44. Ab initio and DFT studies of the vibrational spectra of hydrogen-bonded PhOH...(H2O)4 complexes.
- Author
-
Dimitrova Y
- Subjects
- Hydrogen Bonding, Molecular Structure, Spectrophotometry, Infrared, Hydrogen chemistry, Phenol chemistry, Vibration, Water chemistry
- Abstract
The vibrational characteristics (vibrational frequencies and infrared intensities) for the hydrogen-bonded complex of phenol with four water molecules PhOH...(H2O)4 (structure 4A) have been predicted using ab initio and DFT (B3LYP) calculations with 6-31G(d,p) basis set. The changes in the vibrational characteristics from free monomers to a complex have been calculated. The ab initio and B3LYP calculations show that the observed four intense bands at 3299, 3341, 3386 and 3430 cm(-1) can be assigned to the hydrogen-bonded OH stretching vibrations in the complex PhOH...(H2O)4 (4A). The complexation leads to very large red shifts of these vibrations and very strong increase in their IR intensity. The predicted red shifts for these vibrations with B3LYP/6-31G(d,p) calculations are in very good agreement with the experimentally observed. It was established that the phenolic OH stretching vibration is the most sensitive to the hydrogen bonding. The predicted red-shift with the B3LYP/6-31G(d,p) calculations for the most stable ring structure 4A (-590 cm(-1)) is in better agreement with the experimentally observed than the red-shift, predicted with SCF/6-31G(d,p) calculations. The magnitude of the wavenumber shift is indicative of relatively strong OH...H hydrogen-bonded interaction. The complexation between phenol and four water molecules leads to strong increase of the IR intensity of the phenolic OH stretching vibration (up to 38 times).
- Published
- 2004
- Full Text
- View/download PDF
45. Theoretical study of the structures, stability and vibrational spectra of the nitrous acid complexes with CH4.
- Author
-
Dimitrova Y
- Subjects
- Drug Stability, Hydrogen Bonding, Molecular Structure, Spectrophotometry, Infrared, Spectrum Analysis, Thermodynamics, Methane chemistry, Nitrous Acid chemistry
- Abstract
The structures, stability and vibrational spectra of the binary complexes CH4...HONO-trans and CH4...HONO-cis have been investigated using ab initio calculations at the SCF and MP2 levels with 6-311++G(d,p) basis set and B3LYP calculations with 6-31G(d,p) and 6-31+G(d,p) basis sets. Full geometry optimization was made for the complexes studied. It was established that the complex CH4...HONO-trans is more stable by 0.41 kcal mol(-1) than the complex CH4...HONO-cis. The accuracy of the ab initio calculations have been estimated by comparison between the predicted values of the vibrational characteristics (vibrational frequencies and infrared intensities) and the available experimental data. It was established, that the methods, used in this study are well adapted to the problem under examination. The predicted values with the B3LYP calculations are very near to the results, obtained with 6-311++G(d,p)/MP2. The changes in the vibrational characteristics of methane and trans-, cis-nitrous acid upon formation of the hydrogen bond show that the complexes CH4...HONO-trans and CH4...HONO-cis have geometry in which the OH group interacts with a methane molecule forming a single hydrogen bond. This fact is confirmed by relatively strong perturbation of the OH stretching vibration to lower frequencies and an increase of the infrared intensity of this vibration up to three times upon hydrogen bonding.
- Published
- 2004
- Full Text
- View/download PDF
46. Structure, stability and vibrational spectrum of the hydrogen-bonded complex between HNO3 and H2O. Ab initio and DFT studies.
- Author
-
Dimitrova Y
- Subjects
- Hydrogen, Hydrogen Bonding, Models, Chemical, Molecular Conformation, Molecular Structure, Nitric Acid metabolism, Oxygen, Protein Conformation, Spectrophotometry, Infrared, Spectrum Analysis, Raman, Thermodynamics, Nitric Acid chemistry, Spectrophotometry methods, Water chemistry
- Abstract
The structure, stability and vibrational spectrum of the binary complex between HONO2 and H2O have been investigated using ab initio calculations at SCF and MP2 levels with different basis sets and B3LYP/6-31G(d,p) calculations. Full geometry optimization was made for the complex studied. It was established that the hydrogen-bonded H2O...HONO2 complex has a planar structure. The corrected values of the dissociation energy at the SCF and MP2 levels and B3LYP calculations are indicative of relatively strong OH...O hydrogen-bonded interaction. The changes in the vibrational characteristics (vibrational frequencies and infrared intensities) arising from the hydrogen bonding between HONO2 and H2O have been estimated by using the ab initio calculations at SCF and MP2 levels and B3LYP/6-31G(d,p) calculations. It was established that the most sensitive to the complexation is the stretching O-H vibration from HONO2. In agreement with the experiment, its vibrational frequency in the complex is shifted to lower wavenumbers. The predicted frequency shift with the B3LYP/6-31G(d,p) calculations (-439 cm(-1)) is in the best agreement with the experimentally measured (-498 cm(-1)). The intensity of this vibration increases dramatically upon hydrogen bonding. The ab initio calculations at the SCF level predict an increase up to five times; at the MP2 level up to 10 times and the B3LYP/6-31G(d,p) predicted increase is up to 17 times. The good agreement between the predicted values of the frequency shifts and those experimentally observed show that the structure of the hydrogen-bonded complex H2O...HONO2 is reliable.
- Published
- 2004
- Full Text
- View/download PDF
47. Ab initio prediction of the vibrational spectrum of the hydrogen bonded complex O2N...HONO2.
- Author
-
Dimitrova Y
- Subjects
- Spectrophotometry, Infrared, Spectrum Analysis, Raman, Hydrogen Bonding, Nitric Acid chemistry, Nitrogen Dioxide chemistry
- Abstract
The changes in the structural parameters and vibrational characteristics (vibrational frequencies, infrared intensities and Raman activities) arising from the hydrogen bonding between NO(2) and HONO(2) have been studied employing ab initio 6-31G(d, p)/UHF and 6-31+G(d, p)/UHF, and B3LYP/6-31G(d, p) calculations. The charge rearrangement upon hydrogen bonding have been, estimated using the Mulliken population analyses. It was established that the complexation between NO(2) and HONO(2) leads to changes in the structural parameters and the vibrational characteristics of the monomers. The most sensitive to the hydrogen bond formation are the vibrational characteristics of the normal modes of the monomer bonds participating in the hydrogen bonding. The predicted shifts in the vibrational frequencies by ab initio and B3LYP/6-31G(d, p) calculations are in very good agreement with the experimentally observed, which is an evidence for the reliance of the studied structure.
- Published
- 2003
- Full Text
- View/download PDF
48. Translocating proline-rich peptides from the antimicrobial peptide bactenecin 7.
- Author
-
Sadler K, Eom KD, Yang JL, Dimitrova Y, and Tam JP
- Subjects
- Amino Acid Sequence, Animals, Anti-Bacterial Agents, Anti-Infective Agents chemical synthesis, Anti-Infective Agents pharmacology, Anti-Infective Agents toxicity, Antifungal Agents pharmacology, Candida albicans drug effects, Cations metabolism, Cell Line, Cell Membrane Permeability drug effects, Cell Survival drug effects, Drug Delivery Systems methods, Escherichia coli drug effects, Hydrophobic and Hydrophilic Interactions, Mice, Molecular Sequence Data, Monocytes drug effects, Monocytes metabolism, Peptide Fragments chemical synthesis, Peptide Fragments metabolism, Peptide Fragments pharmacology, Peptide Fragments toxicity, Peptides chemical synthesis, Peptides pharmacology, Peptides toxicity, Peptides, Cyclic chemical synthesis, Peptides, Cyclic pharmacology, Peptides, Cyclic toxicity, Proline-Rich Protein Domains, Protein Transport, Repetitive Sequences, Amino Acid, Staphylococcus aureus drug effects, Anti-Infective Agents metabolism, Peptides metabolism, Peptides, Cyclic metabolism, Proline metabolism
- Abstract
The intracellular delivery of most peptides, proteins, and nucleotides to the cytoplasm and nucleus is impeded by the cell membrane. To allow simplified, noninvasive delivery of attached cargo, cell-permeant peptides that are either highly cationic or hydrophobic have been utilized. Because cell-permeable peptides share half of the structural features of antimicrobial peptides containing clusters of charge and hydrophobic residues, we have explored antimicrobial peptides as templates for designing cell-permeant peptides. We prepared synthetic fragments of Bac 7, an antimicrobial peptide with four 14-residue repeats from the bactenecin family. The dual functions of cell permeability and antimicrobial activity of Bac 7 were colocalized at the N-terminal 24 residues of Bac 7. In general, long fragments of Bac(1-24) containing both regions were bactericidal and cell-permeable, whereas short fragments with only a cationic or hydrophobic region were cell-permeant without the attendant microbicidal activity when measured in a fluorescence quantitation assay and by confocal microscopy. In addition, the highly cationic fragments were capable of traversing the cell membrane and residing within the nucleus. A common characteristic shared by the cell-permeant Bac(1-24) fragments, irrespective of their number of charged cationic amino acids, is their high proline content. A 10-residue proline-rich peptide with two arginine residues was capable of delivering a noncovalently linked protein into cells. Thus, the proline-rich peptides represent a potentially new class of cell-permeant peptides for intracellular delivery of protein cargo. Furthermore, our results suggest that antimicrobial peptides may represent a rich source of templates for designing cell-permeant peptides.
- Published
- 2002
- Full Text
- View/download PDF
49. The effect of BCG treatment on gastric carcinoma--three case reports.
- Author
-
Hadjiev S, Kavaklieva-Dimitrova Y, Raychev R, Mandulova P, Delov I, Spasova M, and Madjarova S
- Subjects
- Aged, Female, Humans, Male, Middle Aged, Adenocarcinoma therapy, BCG Vaccine therapeutic use, Carcinoma therapy, Stomach Neoplasms therapy
- Published
- 1981
50. Immunotherapy with BCG as an independent treatment of lung cancer.
- Author
-
Hadzhiev S, Dimitrova Y, Mandulova P, Spassova M, and Madjarova S
- Subjects
- Combined Modality Therapy, Humans, Lung Neoplasms mortality, Lung Neoplasms pathology, BCG Vaccine therapeutic use, Lung Neoplasms therapy
- Published
- 1985
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