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Puel TO, Chesi S, Kirchner S, Ribeiro P. Mixed-Order Symmetry-Breaking Quantum Phase Transition Far from Equilibrium. Phys Rev Lett 2019; 122:235701. [PMID: 31298904 DOI: 10.1103/physrevlett.122.235701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Indexed: 06/10/2023]
Abstract
We study the current-carrying steady state of a transverse field Ising chain coupled to magnetic thermal reservoirs and obtain the nonequilibrium phase diagram as a function of the magnetization potential of the reservoirs. Upon increasing the magnetization bias we observe a discontinuous jump of the magnetic order parameter that coincides with a divergence of the correlation length. For steady states with a nonvanishing conductance, the entanglement entropy at zero temperature displays a bias dependent logarithmic correction that violates the area law and differs from the well-known equilibrium case. Our findings show that out-of-equilibrium conditions allow for novel critical phenomena not possible at equilibrium.
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Affiliation(s)
- T O Puel
- Beijing Computational Science Research Center, Beijing 100193, China
- CeFEMA, Instituto Superior Técnico, Universidade de Lisboa Av. Rovisco Pais, 1049-001 Lisboa, Portugal
- Zhejiang Institute of Modern Physics, Zhejiang University, Hangzhou, Zhejiang 310027, China
- Zhejiang Province Key Laboratory of Quantum Technology and Devices, Zhejiang University, Hangzhou 310027, China
| | - Stefano Chesi
- Beijing Computational Science Research Center, Beijing 100193, China
- Department of Physics, Beijing Normal University, Beijing 100875, China
| | - S Kirchner
- Zhejiang Institute of Modern Physics, Zhejiang University, Hangzhou, Zhejiang 310027, China
- Zhejiang Province Key Laboratory of Quantum Technology and Devices, Zhejiang University, Hangzhou 310027, China
| | - P Ribeiro
- Beijing Computational Science Research Center, Beijing 100193, China
- CeFEMA, Instituto Superior Técnico, Universidade de Lisboa Av. Rovisco Pais, 1049-001 Lisboa, Portugal
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Madeira S, Mesquita-Guimarães J, Ribeiro P, Fredel M, Souza JCM, Soares D, Silva FS, Henriques B. Y-TZP/porcelain graded dental restorations design for improved damping behavior - A study on damping capacity and dynamic Young's modulus. J Mech Behav Biomed Mater 2019; 96:219-226. [PMID: 31055212 DOI: 10.1016/j.jmbbm.2019.04.033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 04/16/2019] [Accepted: 04/17/2019] [Indexed: 01/12/2023]
Abstract
The development of dental restorative materials that mimic tooth-like properties provided by graded structures, aesthetics and properties such as strength, damping capacity and the ability for a continuous remodeling according to the biomechanical solicitation is a great challenge. In this work, damping capacity and dynamic Young's modulus of Y-TZP/porcelain composites for all-ceramic dental restorations were studied. These mechanical properties were assessed by dynamic mechanical analyses (DMA) at frequencies of 1, 5 and 10 Hz, over a temperature ranging from 0 to 60 °C, simulating extreme conditions when a cold or hot drink is experienced. The results showed that porcelain and porcelain-matrix composites exhibited higher damping capacity while Y-TZP and Y-TZP-matrix composites presented higher dynamic Young's modulus. Furthermore, while damping capacity is strongly influenced by the temperature, no significant difference in dynamic Young's modulus was found. For both damping and modulus properties, no significant influence of frequency was found for the tested materials. Based on the obtained results and also on the known advantages of the graded Y-TZP/porcelain structures over traditional bi-layer solutions (e.g., improved bending strength, enhanced mechanical and thermal stress distribution), a novel design of all-ceramic restoration with damping capacity has been proposed at the end of this study. A positive impact on the long-term performance of these all-ceramic restorations may be expected.
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Affiliation(s)
- S Madeira
- Center for Micro-Electro Mechanical Systems (CMEMS), University of Minho, Campus de Azurém, 4800-058, Guimarães, Portugal.
| | - J Mesquita-Guimarães
- Center for Micro-Electro Mechanical Systems (CMEMS), University of Minho, Campus de Azurém, 4800-058, Guimarães, Portugal.
| | - P Ribeiro
- Center for Micro-Electro Mechanical Systems (CMEMS), University of Minho, Campus de Azurém, 4800-058, Guimarães, Portugal
| | - M Fredel
- Ceramic and Composite Materials Research Group (CERMAT), Federal University of Santa Catarina (UFSC), Campus Trindade, Florianópolis, SC, Brazil
| | - J C M Souza
- Center for Micro-Electro Mechanical Systems (CMEMS), University of Minho, Campus de Azurém, 4800-058, Guimarães, Portugal; Department of Dental Sciences, University Institute of Health Sciences (IUCS), CESPU, Gandra, Portugal
| | - D Soares
- Center for Micro-Electro Mechanical Systems (CMEMS), University of Minho, Campus de Azurém, 4800-058, Guimarães, Portugal
| | - F S Silva
- Center for Micro-Electro Mechanical Systems (CMEMS), University of Minho, Campus de Azurém, 4800-058, Guimarães, Portugal
| | - Bruno Henriques
- Center for Micro-Electro Mechanical Systems (CMEMS), University of Minho, Campus de Azurém, 4800-058, Guimarães, Portugal; Ceramic and Composite Materials Research Group (CERMAT), Federal University of Santa Catarina (UFSC), Campus Trindade, Florianópolis, SC, Brazil; School of Dentistry (DODT), Post-Graduate Program in Dentistry (PPGO), Federal University of Santa Catarina, Campus Trindade, 88040-900, Florianópolis, SC, Brazil.
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Negri M, Gorgora M, Nasser JA, Salles JI, Teixeira S, Arias-Carrión O, Junqueira J, Nicoliche E, Velasques B, Cagy M, Budde H, Basile LF, Orsini M, Friede R, Bastos VH, Ribeiro P. Neurophysiological changes after cognitive-motor tasks in Parkinson's disease patients with deep brain stimulation. Funct Neurol 2019; 34:177-187. [PMID: 32453999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Chronic deep brain stimulation (CDBS) is a surgical treatment that reduces the cardinal signs of Parkinson's disease (PD). Although CDBS has been in use for a long time, very little has been reported on its supposed effects on cognition, particularly in relation to implants in the subthalamic nucleus. The results of the rare studies that do exist are controversial, and in many cases the studies have several design flaws. The present study compared cortical activation during three tasks (action execution, action observation and motor imagery) in PD patients with and without subthalamic implants. The study sample consisted of 36 volunteers, divided into three groups: healthy controls, PD patients with CDBS of the subthalamic nucleus, and PD patients without CDBS. Through a quantitative electroencephalogram assessment, absolute beta power was examined to observe the interaction between group and cognitive motor tasks. The electrodes at sites Fp1, Fp2, F7, F8, F3, Fz and F4, located in the prefrontal and frontal regions, were analyzed and a Group x Task interaction (p < 0.05) was observed for all of them. These findings suggest that CDBS of the subthalamic nucleus is efficient in reducing some of the effects of PD in these study tasks. At the same time, the dysfunctions found in several cortical areas, characteristic of PD, limited the effects of the CDBS. The results of this study suggest that CDBS of the subthalamic nucleus can modulate cognitive-motor aspects of PD.
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Abstract
In the last three decades, fractal geometry became a mathematical tool widely used in physics. Nevertheless, it has been observed that real multi-scale phenomena display a departure to fractality that implies an impossibility to define the multi-scale features with an unique fractal dimension, leading to variations in the scale-space. The scale-entropy diffusion equation theorizes the organization of the scale dynamics involving scale-dependent fractals. A study of the theory is possible through the scale-entropy sink term in the equation and corresponds to precise behaviours in scale-space. In the first part of the paper, we study the scale space features when the scale-entropy sink term is modified. The second part is a numerical investigation and analysis of several solutions of the scale-entropy diffusion equation. By a precise measurement of the transition scales tested on truncated deterministic fractals, we developed a new simple method to estimate fractal dimension which appears to be much better than a classical method. Furthermore, we show that deterministic fractals display intrinsic log-periodic oscillations of the fractal dimension. In order to represent this complex behaviour, we introduce a departure to fractal diagram linking scale-space, scale-dependent fractal dimension and scale-entropy sink. Finally, we construct deterministic scale-dependent fractals and verify the results predicted by the scale-entropy diffusion equation.
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Brand J, Ribeiro P, Néel N, Kirchner S, Kröger J. Impact of Atomic-Scale Contact Geometry on Andreev Reflection. Phys Rev Lett 2017; 118:107001. [PMID: 28339246 DOI: 10.1103/physrevlett.118.107001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Indexed: 06/06/2023]
Abstract
Charge transport has been examined in junctions comprising the normal-metal tip of a low-temperature scanning tunneling microscope, the surface of a conventional superconductor, and adsorbed C_{60} molecules. The Bardeen-Cooper-Schrieffer energy gap gradually evolves into a zero-bias peak with decreasing electrode separation. The peak is assigned to the spectroscopic signature of Andreev reflection. The conductance due to Andreev reflection is determined by the atomic termination of the tip apex and the molecular adsorption orientation. Transport calculations unveil the finite temperature and the strong molecule-electrode hybridization as the origin to the surprisingly good agreement between spectroscopic data and the Blonder-Tinkham-Klapwijk model that was conceived for macroscopic point contacts.
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Affiliation(s)
- J Brand
- Institut für Physik, Technische Universität Ilmenau, D-98693 Ilmenau, Germany
| | - P Ribeiro
- CeFEMA, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
| | - N Néel
- Institut für Physik, Technische Universität Ilmenau, D-98693 Ilmenau, Germany
| | - S Kirchner
- Center for Correlated Matter, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - J Kröger
- Institut für Physik, Technische Universität Ilmenau, D-98693 Ilmenau, Germany
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Leite A, Martins L, Ribeiro P, Silva B, Teles A. Instrument Separation during the Non Surgical Endodontic Treatment. Causes, prevention and clinical approach. J Clin Exp Dent 2017. [DOI: 10.4317/medoral.176438649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Sal Moyano MP, Lorusso M, Nuñez J, Ribeiro P, Gavio MA, Luppi T. Male size-dependent dominance for burrow holding in the semiterrestrial crab Neohelice granulata: multiple tactics used by intermediate-sized males. Behav Ecol Sociobiol 2016. [DOI: 10.1007/s00265-016-2158-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Pereira L, Soares G, Dias M, Ribeiro P, Pinheiro M, Luz K. AB0959 The Automated Software-Guided Ultrasound Assessment of Bilateral Common Carotids Intima-Media Thickness for Investigation of Cardiovascular Risk: Comparison between Psoriatic and Rheumatoid Arthritis Patients. Ann Rheum Dis 2016. [DOI: 10.1136/annrheumdis-2016-eular.3782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Burbarelli MFC, Merseguel CEB, Ribeiro PAP, Lelis KD, Polycarpo GV, Carão ACP, Bordin RA, Fernandes AM, Souza RLM, Moro MEG, Albuquerque R. The Effects of Two Different Cleaning and Disinfection Programs on Broiler Performance and Microbiological Status of Broiler Houses. Rev Bras Cienc Avic 2015. [DOI: 10.1590/1516-635x1704575-580] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Ribeiro P, Zamani F, Kirchner S. Steady-State Dynamics and Effective Temperature for a Model of Quantum Criticality in an Open System. Phys Rev Lett 2015; 115:220602. [PMID: 26650286 DOI: 10.1103/physrevlett.115.220602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Indexed: 06/05/2023]
Abstract
We study the thermal and nonthermal steady-state scaling functions and the steady-state dynamics of a model of local quantum criticality. The model we consider, i.e., the pseudogap Kondo model, allows us to study the concept of effective temperatures near fully interacting as well as weak-coupling fixed points. In the vicinity of each fixed point we establish the existence of an effective temperature-different at each fixed point-such that the equilibrium fluctuation-dissipation theorem is recovered. Most notably, steady-state scaling functions in terms of the effective temperatures coincide with the equilibrium scaling functions. This result extends to higher correlation functions as is explicitly demonstrated for the Kondo singlet strength. The nonlinear charge transport is also studied and analyzed in terms of the effective temperature.
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Affiliation(s)
- P Ribeiro
- Russian Quantum Center, Novaya street 100 A, Skolkovo, Moscow area, 143025 Russia and CeFEMA, Instituto Superior Técnico, Universidade de Lisboa Avenida Rovisco Pais, 1049-001 Lisboa, Portugal
| | - F Zamani
- Max Planck Institute for Physics of Complex Systems, 01187 Dresden, Germany and Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - S Kirchner
- Center for Correlated Matter, Zhejiang University, Hangzhou, Zhejiang 310058, China
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Magalhães S, Ribeiro P, Braga A, Schelp A. The impact of botulinum toxin type A treatment on a patient with lingual dystonia: case report. J Neurol Sci 2015. [DOI: 10.1016/j.jns.2015.08.1264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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12
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Vinhas R, Correia C, Ribeiro P, Lourenço A, Sousa A, Fernandes A, Baptista P. 179 GOLD NANOPROBES IN THE DIAGNOSTIC OF CHRONIC MYELOID LEUKEMIA: DETECTION OF THE E14A2 BCR-ABL TRANSCRIPT DIRECTLY IN RNA SAMPLES. Leuk Res 2015. [DOI: 10.1016/s0145-2126(15)30180-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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13
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Ribeiro PAP, Matos Jr JB, Lara LJC, Araújo LF, Albuquerque R, Baião NC. Effect of dietary energy concentration on performance parameters and egg quality of white leghorn laying hens. Rev Bras Cienc Avic 2014. [DOI: 10.1590/1516-635x1604381-388] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
| | | | - LJC Lara
- Universidade Federal de Minas, Brazil
| | | | | | - NC Baião
- Universidade Federal de Minas, Brazil
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Faria J, Rivas M, Martins GM, Hawkins SJ, Ribeiro P, Pita A, Neto AI, Presa P. A new multiplexed microsatellite tool for metapopulation studies in the overexploited endemic limpet Patella aspera (Röding, 1798). Anim Genet 2014; 46:96-7. [PMID: 25351981 DOI: 10.1111/age.12243] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/26/2014] [Indexed: 11/29/2022]
Affiliation(s)
- J Faria
- CIIMAR/CIMAR - Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Rua dos Bragas 289, Porto, 4050-123, Portugal; Centre for Research in Natural Resources, Department of Biology, University of Azores, S. Miguel, Ponta Delgada, 9501-801, Azores, Portugal
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Oliveira TP, Ribeiro P, Sacramento PD. Entanglement entropy and entanglement spectrum of triplet topological superconductors. J Phys Condens Matter 2014; 26:425702. [PMID: 25274448 DOI: 10.1088/0953-8984/26/42/425702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We analyze the entanglement entropy properties of a 2D p-wave superconductor with Rashba spin-orbit coupling, which displays a rich phase-space that supports non-trivial topological phases, as the chemical potential and the Zeeman term are varied. We show that the entanglement entropy and its derivatives clearly signal the topological transitions and we find numerical evidence that for this model the derivative with respect to the magnetization provides a sensible signature of each topological phase. Following the area law for the entanglement entropy, we systematically analyze the contributions that are proportional to or independent of the perimeter of the system, as a function of the Hamiltonian coupling constants and the geometry of the finite subsystem. For this model, we show that even though the topological entanglement entropy vanishes, it signals the topological phase transitions in a finite system. We also observe a relationship between a topological contribution to the entanglement entropy in a half-cylinder geometry and the number of edge states, and that the entanglement spectrum has robust modes associated with each edge state, as in other topological systems.
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Affiliation(s)
- T P Oliveira
- Centro de Física das Interacções Fundamentais, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal. Departamento de Física, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, Santa Catarina, Brazil
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Murarolli VDA, Burbarelli MFC, Polycarpo GV, Ribeiro PAP, Moro MEG, Albuquerque R. Prebiotic, probiotic and symbiotic as alternative to Antibiotics on the Performance and Immune Response of Broiler Chickens. Rev Bras Cienc Avic 2014. [DOI: 10.1590/1516-635x1603279-284] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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17
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Miranda C, Matos M, Pires I, Correia-Neves M, Ribeiro P, Alvares S, Vieira-Pinto M, Coelho AC. Diagnosis of Mycobacterium avium complex in granulomatous lymphadenitis in slaughtered domestic pigs. J Comp Pathol 2012; 147:401-5. [PMID: 22784782 DOI: 10.1016/j.jcpa.2012.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Revised: 04/10/2012] [Accepted: 05/03/2012] [Indexed: 11/27/2022]
Abstract
The aim of this study was to compare two diagnostic methods for the detection of Mycobacterium avium complex (MAC) infection in lymph nodes with granulomatous lymphadenitis from slaughtered domestic pigs. Fifty affected lymph nodes were collected from 50 pigs and examined microscopically and by polymerase chain reaction (PCR). Microscopically, granulomatous lesions were observed in 92% of the samples, consisting mostly of central necrosis (78%) with dystrophic calcification (46%) and associated with inflammatory infiltration by epithelioid giant cells, lymphocytes, neutrophils (92%), eosinophils (60%) and Langhans-type cells (70%). In 64% of the lesions, a capsule of connective tissue was found. Acid-fast bacilli were observed in all cases. PCR detected DNA from Mycobacterium spp. in 82% (41/50) of the lymph nodes. MAC was confirmed in 58% (24/41) and M. avium avium/silvaticum subspecies in 39% (16/41). The results of this study suggest that combined histopathology and PCR of lymph nodes are useful in the diagnosis of granulomatous lymphadenitis in slaughtered pigs.
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Affiliation(s)
- C Miranda
- Department of Veterinary Sciences, CECAV, University of Trás-os-Montes and Alto Douro (UTAD), 5001-801 Vila Real.
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Hammerath F, Nishimoto S, Grafe HJ, Wolter AUB, Kataev V, Ribeiro P, Hess C, Drechsler SL, Büchner B. Spin gap in the zigzag spin-1/2 chain cuprate Sr(0.9)Ca(0.1)CuO(2). Phys Rev Lett 2011; 107:017203. [PMID: 21797568 DOI: 10.1103/physrevlett.107.017203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Revised: 05/26/2011] [Indexed: 05/31/2023]
Abstract
We report a comparative study of (63)Cu nuclear magnetic resonance spin lattice relaxation rates T(1)(-1) on undoped SrCuO(2) and Ca-doped Sr(0.9)Ca(0.1)CuO(2) spin chain compounds. A temperature independent T(1)(-1) is observed for SrCuO(2) as expected for an S=1/2 Heisenberg chain. Surprisingly, we observe an exponential decrease of T(1)(-1) for T<90 K in the Ca-doped sample evidencing the opening of a spin gap. The data analysis within the J(1)-J(2) Heisenberg model employing density-matrix renormalization group calculations suggests an impurity driven small alternation of the J(2)-exchange coupling as a possible cause of the spin gap.
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Affiliation(s)
- F Hammerath
- Leibniz Institute for Solid State and Materials Research IFW Dresden, Germany
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Jorge J, Fernandes P, Queirós A, Ribeiro P, Ferreira A, Gonzalez-Meijome JM. Clinical evaluation of the IOPen® in a glaucomatous population. Ophthalmic Physiol Opt 2011; 30:860-4. [PMID: 21205273 DOI: 10.1111/j.1475-1313.2010.00783.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The aim of this study was to evaluate the level of agreement of measurements of intraocular pressure (IOP) taken by a rebound tonometer (IOPen®), in comparison to a reference Goldmann applanation tonometer (GAT) in a glaucomatous population. Both eyes from 60 patients were assessed with the two tonometers, the induction tonometry was performed first by an experienced optometrist, and the GAT by an ophthalmologist. In this study, statistically significant differences were found when comparing the IOPen® tonometer with the GAT tonometer (p < 0.001), mean differences were -4.81 ± 4.31 and -4.76 ± 5.76 mmHg (mean ± S.D.) for the right eye and left eye respectively These values represent an underestimation in the present population by the IOPen® when compared with the GAT. Frequency distribution of differences demonstrated that in more than 71.6% of the measurements the IOP readings differed by more than 3 mmHg between the two tonometers. These results suggest that IOPen® should be used with great caution in the determination of IOP.
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Affiliation(s)
- J Jorge
- Center of Physics, School of Science, University of Minho, Campus de Gualtar, Braga, Portugal.
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Abstract
We discuss the entanglement properties of symmetric states of n qubits. The Majorana representation maps a generic such state into a system of n points on a sphere. Entanglement invariants, either under local unitaries (LU) or stochastic local operations and classical communication (SLOCC), can then be addressed in terms of the relative positions of the Majorana points. In the LU case, an overcomplete set of invariants can be built from the inner product of the radial vectors pointing to these points; this is detailed for the well-documented three-qubits case. In the SLOCC case, a cross ratio of related Möbius transformations are shown to play a central role, exemplified here for four qubits. Finally, as a side result, we also analyze the manifold of maximally entangled 3 qubit state, both in the symmetric and generic case.
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Affiliation(s)
- P Ribeiro
- CFIF, Instituto Superior Técnico, Universidade Técnica de Lisboa, Portugal.
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Salles JI, Alves H, Amaral MV, Cagy M, Cunha-Cruz V, Piedade R, Ribeiro P. Study of proprioceptive function in professional volleyball athletes with atrophy of the infraspinatus. Br J Sports Med 2011. [DOI: 10.1136/bjsm.2011.084558.6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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22
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Velasques B, Machado S, Cunha M, Santos J, Bittencourt J, Budde H, Basile L, Cagy M, Piedade R, Sack A, Cheniaux E, Nardi A, Ribeiro P. Hemispheric differences in frontal theta-band power discriminate between stimulus-versus memory-driven saccadic eye movement. Eur Psychiatry 2011. [DOI: 10.1016/s0924-9338(11)72144-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
IntroductionAlthough several electrophysiological studies have demonstrated the role of theta band during the execution of different visuospatial attention tasks, this study is the first to directly investigate the role of theta power during the planning, execution and cognitive control of SEM.ObjectiveSaccadic eye movements (SEMs) represent the first stage of visual sensorimotor integration and are relevant for the visuospatial attention. The current study aims to address this issue by investigating absolute theta power over the frontal cortex during the execution of stimulus- and memory-driven SEMs.Methods12 healthy volunteers (3 male; mean age: 26.25), performed two tasks involving different conditions in the planning, execution and cognitive control of SEMs while their brain activity pattern is recorded using quantitative electroencephalography.ResultsWe found an interaction between SEM condition (memory- vs stimulus-driven) and electrode (F3, F4, Fz), and a main effect of time point and electrode. Our key finding revealed that the stimulus presentation induces different patterns over frontal theta power increase between the left and right hemisphere.ConclusionsWe conclude that right and left frontal regions are an important factor to discriminate between memory- versus stimulus-driven SEMs, and speculate on their role for different levels within the visuospatial attention.
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Teixeira S, Velasques B, Machado S, Paes F, Cunha M, Budde H, Anghinah R, Basile LFH, Cagy M, Piedade R, Ribeiro P. Gamma band oscillations in parietooccipital areas during performance of a sensorimotor integration task: a qEEG coherence study. Arq Neuro-Psiquiatr 2011; 69:304-9. [PMID: 21625755 DOI: 10.1590/s0004-282x2011000300007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Accepted: 11/11/2010] [Indexed: 11/21/2022]
Abstract
This study aimed to elucidate cortical mechanisms involved in anticipatory actions when 23 healthy right-handed subjects had to catch a free falling object through quantitative electroencephalogram (qEEG). For this reason, we used coherence that represents a measurement of linear covariation between two signals in the frequency domain. In addition, we investigated gamma-band (30-100 Hz) activity that is related to cognitive and somatosensory processes. We hypothesized that gamma coherence will be increase in both parietal and occipital areas during moment after ball drop, due to their involvement in manipulation of objects, visuospatial processing, visual perception, stimuli identification and attention processes. We confirmed our hypothesis, an increase in gamma coherence on P3-P4 (t= -2.15; p=0.033) and PZ-OZ (t= -2.16; p=0.034) electrode pairs was verified for a paired t-test. We conclude that to execute tasks involving anticipatory movements (feedforward mechanisms), like our own task, probably, there is no need of a strong participation of visual areas in the process of information organization to manipulate objects and to process visuospatial information regarding the contact hand-object.
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Affiliation(s)
- S Teixeira
- Federal University of Rio de Janeiro, Brazil
| | - B Velasques
- Federal University of Rio de Janeiro, Brazil; Institute of Applied Neuroscience, Brazil
| | - S Machado
- Federal University of Rio de Janeiro, Brazil; Institute of Applied Neuroscience, Brazil
| | - F Paes
- Federal University of Rio de Janeiro, Brazil; Brazilian Institute of Medicine and Rehabilitation, Brazil
| | - M Cunha
- Federal University of Rio de Janeiro, Brazil; Institute of Applied Neuroscience, Brazil; Federal University of Vale do São Francisco, Brazil
| | - H Budde
- Humboldt Universität zu Berlin, Germany
| | - R Anghinah
- University of São Paulo Medical School, Brazil
| | - L F H Basile
- University of São Paulo Medical School, Brazil; UMESP, Brazil
| | - M Cagy
- Federal Fluminense University, Brazil
| | - R Piedade
- Federal University of Rio de Janeiro, Brazil
| | - P Ribeiro
- Federal University of Rio de Janeiro, Brazil; UFRJ, Brazil; Institute of Applied Neuroscience, Brazil
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Lattari E, Velasques B, Paes F, Cunha M, Budde H, Basile L, Cagy M, Piedade R, Machado S, Ribeiro P. Corticomuscular coherence behavior in fine motor control of force: a critical review. Rev Neurol 2010; 51:610-623. [PMID: 21069640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
INTRODUCTION Understanding how the human motor control operates is an important issue to the neuroscience. One example is how the motor cortex controls muscle activity, which can be observed through corticomuscular coherence (CMC). AIM Our study aimed to verify the influence of certain factors related to the fine motor control of force tasks on CMC. Our issue is if would be possible the strength of the coupling between the central and muscular systems measured by changes in oscillatory activity of beta- and gamma-band being influenced by these factors as much healthy subjects as patients. DEVELOPMENT Beta-band CMC was especially important when executing sustaining accurate control tasks, which need more concentration and effort. However, we found that beta-band CMC was influenced by some factors. With regard to gamma-band CMC, apparently a complex and continuous dynamic integration of several mechanisms would be necessary to modulate gamma-band CMC, since it was not modulated by magnitude of force. Therefore, it seems these mechanisms would be required to an adequate and effective neural networks operation when a dynamic force output is required. CONCLUSION Beta- and gamma-band CMC could enrich our understanding of the dynamic changes of the motor system not only in health subjects but also in neurological patients. It may serve as a sensitive index for quantifying dynamical changes in fine motor control of force. It has the potential to become a useful tool to characterize the patterns of changes in central nervous system's activities for the purposes of basic research, especially in restoring of motor function.
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Affiliation(s)
- E Lattari
- Institute of Psychiatry of Federal University of Rio de Janeiro, Bazil
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Jorge J, Fernandes P, Queirós A, Ribeiro P, Garcês C, Gonzalez-Meijome JM. Comparison of the IOPen and iCare rebound tonometers with the Goldmann tonometer in a normal population. Ophthalmic Physiol Opt 2010; 30:108-12. [PMID: 20444114 DOI: 10.1111/j.1475-1313.2009.00697.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This study proposes to evaluate the level of accuracy of intraocular pressure (IOP) measurements of a second generation rebound tonometer (IOPen, taking as references the Goldmann Applanation Tonometer (GAT) and the iCare rebound tonometer. The right eyes of 101 consecutive clinical patients were assessed with the three tonometers. The IOPen and iCare measurements were taken by two different optometrists and the GAT by an ophthalmologist. In this study, statistically significant differences were found when comparing the IOPen tonometer with the other two tonometers (p < 0.001). The IOPen underestimated the IOP value when compared to the GAT and the iCare (mean differences were 2.94 +/- 4.65 mmHg and 3.20 +/- 4.72 mmHg (mean +/- S.D.), respectively). The frequency distribution of differences demonstrated that in more than 55% of measurements the IOP readings differed by more than 3 mmHg between the IOPen and the GAT. Based on the present population study, these results suggest that IOPen measurements should be interpreted with caution.
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Affiliation(s)
- J Jorge
- Department of Physics (Optometry), School of Sciences, University of Minho, Campus de Gualtar, Braga.
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26
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Deslandes A, Moraes H, Alves H, Pompeu F, Silveira H, Mouta R, Arcoverde C, Ribeiro P, Cagy M, Piedade R, Laks J, Coutinho E. Effect of aerobic training on EEG alpha asymmetry and depressive symptoms in the elderly: a 1-year follow-up study. Braz J Med Biol Res 2010; 43:585-92. [DOI: 10.1590/s0100-879x2010007500041] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2009] [Accepted: 04/23/2010] [Indexed: 11/22/2022] Open
Affiliation(s)
| | - H. Moraes
- Universidade Federal do Rio de Janeiro; Universidade Federal do Rio de Janeiro, Brasil
| | - H. Alves
- Universidade Federal do Rio de Janeiro, Brasil
| | | | | | - R. Mouta
- Universidade Federal do Rio de Janeiro
| | | | - P. Ribeiro
- Universidade Federal do Rio de Janeiro, Brasil; Instituto Brasileiro de Biociências Neurais, Brasil
| | - M. Cagy
- Universidade Federal Fluminense, Brasil
| | | | - J. Laks
- Universidade Federal do Rio de Janeiro
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Machado D, Bastos VH, Cunha M, Velasques B, Machado S, Basile L, Cagy M, Piedade R, Ribeiro P. [The effects of bromazepam on the performance of a sensory-motor activity: an electroencephalographic study]. Rev Neurol 2009; 49:295-299. [PMID: 19728275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
AIMS To investigate the effects of using bromazepam on the relative power in alpha while performing a typing task. Bearing in mind the particularities of each brain hemisphere, our hypothesis was that measuring the relative power would allow us to investigate the effects of bromazepam on specific areas of the cortex. More specifically, we expected to observe different patterns of powers in sensory-motor integration, attention and activation processes. SUBJECTS AND METHODS The sample was made up of 39 subjects (15 males and 24 females) with a mean age of 30 +/- 10 years. The control (placebo) and experimental (3 mg and 6 mg of bromazepam) groups were trained in the typing task with a randomised double-blind model. RESULTS A three-way ANOVA and Scheffé test were used to analyse interactions between the factors condition and moment, and between condition and sector. CONCLUSIONS The doses used in this study facilitated motor performance of the typing task. In this study, the use of the drug did not prevent learning of the task, but it did appear to concentrate mental effort on more restricted and specific aspects of typing. It also seemed to influence the rhythm and effectiveness of the operations performed during mechanisms related to the encoding and storage of new information. Likewise, a predominance of activity was observed in the left (dominant) frontal area in the 3 mg bromazepam group, which indicates that this dose of the drug affords the subject a greater degree of directionality of cortical activity for planning and performing the task.
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Affiliation(s)
- D Machado
- Laboratório de Mapeamento Cerebral e Integração Sensório-motor, UFRJ/IPUB, Universidade Federal do Rio de Janeiro. Instituto de Psiquiatria, Rio de Janeiro, Brasil
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Gomes B, Dores G, Ribeiro P, Mela M, Billoët C. 993 CARE THE CARE. Eur J Pain 2009. [DOI: 10.1016/s1090-3801(09)60996-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- B. Gomes
- Pain Unit — Anaesthesia Department, Hospital Garcia da Orta, EPE, Almada, Portugal
| | - G.Ç. Dores
- Acute Pain Unit — Anaesthesia Department, Centro Hospitalar do Porto, EPE, Porto, Portugal
| | - P. Ribeiro
- Anaesthesia Department, CHC — Hospital Pediátrico de Coimbra, Coimbra, Portugal
| | - M. Mela
- Pain Unit — Anaesthesia Department, Hospital Garcia da Orta, EPE, Almada, Portugal
| | - C. Billoët
- Air Liquide santé International, Paris, France
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Mano M, Fernandes A, Ribeiro P. 609 PROCEDURAL PAIN IN CHILDREN. Eur J Pain 2009. [DOI: 10.1016/s1090-3801(09)60612-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- M.Jã. Mano
- Centro Hospitalar de Coimbra, Hospital Pediátrico de Coimbra, Bloco Operatório, Coimbra, Portugal
| | - A. Fernandes
- Escola Superior de Enfermagem de Coimbra, Coimbra, Portugal
| | - P. Ribeiro
- Centro Hospitalar de Coimbra, Hospital Pediátrico de Coimbra, Bloco Operatório, Coimbra, Portugal
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Machado S, Cunha M, Portella CE, Silva JG, Velasques B, Bastos VH, Basile L, Cagy M, Piedade RA, Ribeiro P. [The role played by the parietooccipital cortex in the process of sensory-motor integration: an electroencephalographic study]. Rev Neurol 2008; 47:146-149. [PMID: 18654969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
INTRODUCTION A fundamental aspect of planning future actions is the performance and control of motor tasks. This behaviour is done through sensory-motor integration. AIM To explain the electrophysiological mechanisms in the cortex (modifications to the alpha band) that are involved in anticipatory actions when individuals have to catch a free-falling object. SUBJECTS AND METHODS The sample was made up of 20 healthy subjects of both sexes (11 males and 9 females) with ages ranging between 25 and 40 years (32.5 +/- 7.5) who were free of mental or physical diseases (previous medical history); the subjects were right-handed (Edinburgh Inventory) and were not taking any psychoactive or psychotropic substances at the time of the study. The experiment consisted in a task in which subjects had to catch freely falling objects. The experiment was made up of six blocks of 15 tests, each of which lasted 2 minutes and 30 seconds, with a break of one minute between blocks. Data were captured by means of a quantitative electroencephalogram two seconds before and two seconds after each ball was dropped. RESULTS An interaction of the factors moment and position was only observed for the right parietooccipital cortex, in the combination of electrodes P4-O2. CONCLUSION These findings suggest that the right parietooccipital cortex plays an important role in increasing expectation and swiftness in the processes of preparing for a motor task.
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Affiliation(s)
- S Machado
- Laboratorio de Topografía Cerebral e Integración Sensoriomotora, IPUB/UFRJ, Universidad Federal Fluminense, Brasil.
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Machado S, Portella CE, Silva JG, Velasques B, Bastos VH, Cunha M, Basile L, Cagy M, Piedade RA, Ribeiro P. [Learning and implicit memory: mechanisms and neuroplasticity]. Rev Neurol 2008; 46:543-549. [PMID: 18446697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
INTRODUCTION Learning and memory are complex processes that researchers have been attempting to unravel for over a century in order to gain a clear view of the underlying mechanisms. AIMS To review the basic cellular and molecular mechanisms involved in the process of procedural retention, to offer an overall view of the fundamental mechanisms involved in storing information by means of theories and models of memory, and to discuss the different types of memory and the role played by the cerebellum as a modulator of procedural memory. DEVELOPMENT Experimental results from recent decades have opened up new areas of study regarding the participation of the biochemical and cellular processes related to the consolidation of information in the nervous system. CONCLUSIONS The neuronal circuits involved in acquiring and consolidating memory are still not fully understood and the exact location of memory in the nervous system remains unknown. A number of intrinsic and extrinsic factors interfere in these processes, such as molecular (long-term potentiation and depression) and cellular mechanisms, which respond to communication and transmission between nerve cells. There are also factors that have their origin in the outside environment, which use the association of events to bring about the formation of new memories or may divert the subject from his or her main focus. Memory is not a singular occurrence; it is sub-divided into declarative and non-declarative or, when talking about the time it lasts, into short and long-term memory. Moreover, given its relation with neuronal mechanisms of learning, memory cannot be said to constitute an isolated process.
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Affiliation(s)
- S Machado
- Laboratorio de Cartografía Cerebral e Integración Sensomotora, Instituto de Psiquiatría (IPUB), Universidade Federal do Río de Janeiro, Río de Janeiro, Brasil.
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Abstract
The flatworm nervous system employs a wide repertoire of neuroactive substances, including small chemical messengers, the so called classical transmitters, and several types of neuropeptides. A large body of research accumulated over four decades has provided a wealth of information on the tissue localization and effects of these substances, their biochemistry and, recently, their molecular modes of action in all major classes of flatworms. This evidence will be reviewed, with particular emphasis on the small (classical) transmitters and the receptors that mediate their effects. One of the themes that will emerge from this discussion is that classical transmitters regulate core activities such as movement, metabolism and transport, and thus are essential for survival of the organism. In addition, the evidence shows that flatworms have multiple neurotransmitter receptors, many with unusual pharmacological features, which make them particularly attractive as drug targets. Understanding the molecular basis of these distinctive properties, and developing new, more specific receptor agonists and antagonists will undoubtedly become a major challenge in future research.
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Affiliation(s)
- P Ribeiro
- Institute of Parasitology, McGill University, Macdonald Campus, 21,111 Lakeshore Road, Ste. Anne de Bellevue Quebec, Canada H9X 3V9.
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Piccolo-Daher R, Ribeiro P, Piccolo-Daher S, Piccolo P, Piccolo N, Piccolo-Lobo R, Meirelles R, Piccolo M, Piccolo M, Piccolo N. Tissue expansion-associated factors and complications—A retrospective study. Burns 2007. [DOI: 10.1016/j.burns.2006.10.333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Notbohm S, Ribeiro P, Lake B, Tennant DA, Schmidt KP, Uhrig GS, Hess C, Klingeler R, Behr G, Büchner B, Reehuis M, Bewley RI, Frost CD, Manuel P, Eccleston RS. One- and two-triplon spectra of a cuprate ladder. Phys Rev Lett 2007; 98:027403. [PMID: 17358648 DOI: 10.1103/physrevlett.98.027403] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2006] [Indexed: 05/14/2023]
Abstract
We have performed inelastic neutron scattering on the near ideal spin-ladder compound La4Sr10Cu24O41 as a starting point for investigating doped ladders and their tendency toward superconductivity. A key feature was the separation of one-triplon and two-triplon scattering. Two-triplon scattering is observed quantitatively for the first time and so access is realized to the important strong magnetic quantum fluctuations. The spin gap is found to be 26.4+/-0.3 meV. The data are successfully modeled using the continuous unitary transformation method, and the exchange constants are determined by fitting to be Jleg=186 meV and Jrung=124 meV along the leg and rung, respectively; a substantial cyclic exchange of Jcyc=31 meV is confirmed.
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Affiliation(s)
- S Notbohm
- Hahn-Meitner-Institut Berlin, Berlin, Germany
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Canelhas A, Compérat E, Le Tourneau A, Molina T, Ramos M, Ribeiro P, Pimenta A, Diebold J, Audouin J. Marginal zone lymphoma of both spleen and kidney displaying transformation into large B-cell lymphoma. Int Urol Nephrol 2006; 38:431-7. [PMID: 17115288 DOI: 10.1007/s11255-006-6658-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We report a case of simultaneous involvement of the spleen and the left kidney in a marginal zone lymphoma with a monotypic lymphoplasmacytic cell component, which transformed into a diffuse large B-cell lymphoma of the immunoblastic type. PCR showed that the small and large B-cell populations carried the same type of immunoglobulin heavy chain gene rearrangement. This type of rearrangement was detected in the spleen, the latero-aortic lymphadenopathy and the kidney demonstrating that it is the same lymphoma that affected both organs and the lymph nodes. Primary renal lymphoma is very rare and only a few cases of renal marginal zone lymphoma, MALT type, have been reported. Involvement of simultaneous multiple sites has been described in MALT type lymphoma, but splenic involvement secondary to renal MALT lymphoma seems to have never been observed. Nevertheless, in our case the huge size of the spleen associated with splenic hilar node involvement is consistent with primary splenic marginal zone lymphoma. The extension into latero-aortic lymph nodes of this lymphoma can explain secondary kidney involvement. The nodal Kaposi's sarcoma observed in this patient of Mediterranean origin was probably coincidental.
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Affiliation(s)
- A Canelhas
- Hospital de Santo Antonio, Porto, Portugal
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Fridman S, Bezerra R, Cagy M, Basile L, Piedade RA, Ribeiro P. [The effects of bromazepam on contingent negative variation and reaction time in a visuomotor task]. Rev Neurol 2006; 43:398-402. [PMID: 17006858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
INTRODUCTION Bromazepam is the second most commonly used benzodiazepine in Brazil. Psychophysiological research on this substance is still in its early stages. AIM To determine the neurotoxicity of bromazepam by examining reaction times (RT) and contingent negative variations (CNV). SUBJECTS AND METHODS Using a videogame produced in our laboratory for psychophysiological research purposes (Car Acquisition), 14 healthy volunteers (9 males) aged between 23 and 42 drove a vehicle along a road full of curves (i.e. distractors) while they had to respond to imperative stimuli (i.e. orders to press the button on the joystick) that were preceded by warnings (S1-S2-RM paradigm with distractor). We compared RT, amplitudes and latencies of the CNV at each of the three electrodes on the median line (Fz, Cz and Pz) one hour after random, double-blind and crossed administration of placebo (P), 3 mg of bromazepam (B3) or 6 mg of bromazepam (B6) on different days. STATISTICS one-way ANOVA and Post Hoc Scheffé. RESULTS No significant differences were observed in the RT. At Pz, the CNV amplitudes displayed significant differences for P, B3 and B6 (p = 0.006), and also for B3 and B6 (p = 0.018), with B6 > B3 = P. At Fz, a non-significant tendency (p = 0.074) suggested a difference between the latencies, shorter in B6 than in B3 (p = 0.098), both equivalent to placebo. The mean amplitudes ranged between 2.4 and 5.9 microV. CONCLUSIONS Behavioural and neurophysiological neurotoxicity was insignificant one hour after administration of a single 3 or 6 mg dose of bromazepam in healthy young adults. Low mean amplitudes were compatible with the interference from distractors and did not result in floor effect.
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Affiliation(s)
- S Fridman
- Instituto de Psiquiatría, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil.
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Deslandes AC, Veiga H, Cagy M, Piedade R, Pompeu F, Ribeiro P. Effects of caffeine on the electrophysiological, cognitive and motor responses of the central nervous system. Braz J Med Biol Res 2005; 38:1077-86. [PMID: 16007279 DOI: 10.1590/s0100-879x2005000700011] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Caffeine is the most consumed psychoactive substance in the world. The effects of caffeine have been studied using cognitive and motor measures, quantitative electroencephalography (qEEG) and event-related potentials. However, these methods are not usually employed in combination, a fact that impairs the interpretation of the results. The objective of the present study was to analyze changes in electrophysiological, cognitive and motor variables with the ingestion of caffeine, and to relate central to peripheral responses. For this purpose we recorded event-related potentials and eyes-closed, resting EEG, applied the Stroop test, and measured reaction time. Fifteen volunteers took caffeine (400 mg) or placebo in a randomized, crossover, double-blind design. A significant reduction of alpha absolute power over the entire scalp and of P300 latency at the Fz electrode were observed after caffeine ingestion. These results are consistent with a stimulatory effect of caffeine, although there was no change in the attention (Stroop) test or in reaction time. The qEEG seems to be the most sensitive index of the changes produced by caffeine in the central nervous system since it proved to be capable of detecting changes that were not evident in the tests of cognitive or motor performance.
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Affiliation(s)
- A C Deslandes
- Setor de Mapeamento Cerebral e Integração Sensório-Motora, Instituto de Psiquiatria, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brasil.
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Abstract
We generalize the quantum random walk protocol for a particle in a one-dimensional chain, by using several types of biased quantum coins, arranged in aperiodic sequences, in a manner that leads to a rich variety of possible wave-function evolutions. Quasiperiodic sequences, following the Fibonacci prescription, are of particular interest, leading to a sub-ballistic wave-function spreading. In contrast, random sequences lead to diffusive spreading, similar to the classical random walk behavior. We also describe how to experimentally implement these aperiodic sequences.
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Affiliation(s)
- P Ribeiro
- Groupe de Physique des Solides, Universités Paris 6 et 7, campus Boucicaut, 140 rue de Lourmel, 75015 Paris France.
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Jorge J, González-Méijome JM, Díaz-Rey JA, Almeida JB, Ribeiro P, Parafita MA. Clinical performance of non-contact tonometry by Reichert AT550 in glaucomatous patients. Ophthalmic Physiol Opt 2004; 23:503-6. [PMID: 14622352 DOI: 10.1046/j.1475-1313.2003.00139.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Measuring intraocular pressure (IOP) by non-contact tonometry (NCT) has been demonstrated to be a valid and reliable technique to be used in primary eye care; it is easier to use, it does not transmit infectious diseases, and it is not necessary to use anaesthetic or staining eye drops. Recently, a new NCT device has showed an excellent level of agreement with Goldmann tonometry, but there are no records of its performance in glaucomatous eyes. To rectify this, IOP was measured in twenty-two patients (44 eyes) receiving medical treatment to control elevated IOP, with AT550 and Goldmann tonometry. Mean values of IOP were 18.98 +/- 2.77 and 19.08 +/- 3.02 mmHg using Goldmann and AT550, respectively. Plots of differences against means displayed good agreement (mean difference +/- limits of agreement, -0.09 +/- 3.30); this value was not significantly different from zero (t-test for dependent samples, p = 0.709). In conclusion, IOP values as measured with the AT550 NCT are clinically comparable with those obtained with Goldmann tonometry in glaucomatous patients. This validates this NCT not only for screening of IOP but to follow-up glaucomatous patients with a rapid, non-invasive method.
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Affiliation(s)
- J Jorge
- Department of Physics (Optometry), School of Sciences, University of Minho, Braga, Portugal.
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Abstract
We report the cloning and functional analysis of a Pad1 homologue (SmPOH) from Schistosoma mansoni. SmPOH encodes a protein of approximately 35 kDa with high amino acid identities to yeast Pad1 (65%) and its human homologue, POH1 (78%). Members of the Pad1 family are subunits of the 26S proteasome and have been implicated as positive modulators of transcription in yeast. Recombinant SmPOH expressed in COS7 cells exhibited a punctate pattern of distribution throughout the cytoplasm and nucleus, predominantly in the nuclear periphery, a distribution consistent with that of the cellular proteasome. Transient overexpression of SmPOH in COS7 cells caused a dose-dependent stimulation in AP-1 transcriptional activity, as determined by a reporter gene assay. This effect was associated with a pronounced increase in the levels of cellular c-Jun. In vitro degradation assays further demonstrated that SmPOH specifically decreased the rate of c-Jun degradation in a dose dependent manner. Taken together, these results suggest that SmPOH, and possibly other related Pad1 proteins, function as positive modulators of transcription by increasing the stability of cellular c-Jun, making elevated amounts of this protein available for transactivation of AP-1-responsive genes.
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Affiliation(s)
- J F Nabhan
- Institute of Parasitology, McGill University, 21,111 Lakeshore Road, Québec, H9X3V9, Ste. Anne de Bellevue, Canada
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Mateus N, Proença S, Ribeiro P, Machado JM, De Freitas V. GRAPE AND WINE POLYPHENOLIC COMPOSITION OF REDVitis viniferaVARIETIES CONCERNING VINEYARD ALTITUDE COMPOSICIÓN POLIFENÓLICA DE UVAS Y VINO DE VARIEDADES TINTAS DEVitis viniferaEN FUNCIÓN DE LA ALTITUD DEL VIÑEDO COMPOSICIÓN POLIFENÓLICA DE UVAS E VIÑO DE VARIEDADES TINTAS DEVitis viniferaEN FUNCIÓN DA ALTITUDE DO VIÑEDO. ACTA ACUST UNITED AC 2001. [DOI: 10.1080/11358120109487653] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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42
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Lima M, Teixeira MDA, Fonseca S, Gonçalves C, Guerra M, Queirós ML, Santos AH, Coutinho A, Pinho L, Marques L, Cunha M, Ribeiro P, Xavier L, Vieira H, Pinto P, Justiça B. Immunophenotypic Aberrations, DNA Content, and Cell Cycle Analysis of Plasma Cells in Patients with Myeloma and Monoclonal Gammopathies. Blood Cells Mol Dis 2000; 26:634-45. [PMID: 11358356 DOI: 10.1006/bcmd.2000.0342] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We describe the immunophenotypic and gross DNA defects in 55 patients with myeloma and 50 patients with monoclonal gammopathy and review the literature on this subject (MedLine, 1994-2000). Our data confirmed previous reports indicating that in myeloma nearly all marrow plasma cells are abnormal (98.7 +/- 8.1%). In monoclonal gammopathy the fraction of abnormal plasma cells was 35.0 +/- 32.8%. In both myeloma and monoclonal gammopathy, the most frequent aberrant phenotypic features consisted of absence of expression of CD19, strong expression of CD56, and decreased intensity of expression of CD38; aberrant expression of CD10, CD20, CD22, or CD28 was observed in less than one-third of myeloma cases. The vast majority of cases had two or more phenotypic aberrations. In the DNA studies, 7% of myeloma cases were biclonal and 93% of cases were monoclonal. In those studies with only one plasma cell mitotic cycle, 37% had normal DNA content and 63% were aneuploid (hyperploid, 61%; hypoploid, 2%). The mean percentages of plasma cells in S- and G2M phases were 4.9 +/- 8.5 and 4.4 +/- 6.9%, respectively. Thirty-eight percent of cases had more than 3% of plasma cells in S phase. In monoclonal gammopathy, the DNA index of abnormal plasma cells ranged from 0.89 to 1.30 and the percentage of diploid (31%) and aneuploid (69%) cases was not different from the results found in myeloma. The differences in percentage of abnormal plasma cells in S- (7.4 +/- 8.6%) and G2M-phases (2.4 +/- 1.7%) in patients with monoclonal gammopathy were not statistically significant.
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Affiliation(s)
- M Lima
- Service of Clinical Hematology, Hospital Geral de Santo António, Rua D Manual II, s/n, 4050 Porto, Portugal.
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Renard N, Valladeau J, Barthelemy C, Ribeiro P, Berger F, Saeland S, Salles G. Characterization of germinal center dendritic cells in follicular lymphoma. Exp Hematol 1999; 27:1768-75. [PMID: 10641594 DOI: 10.1016/s0301-472x(99)00114-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A subset of dendritic cells called germinal center dendritic cells (GCDC) has recently been described inside germinal center from reactive lymphoid organs. We investigated this newly recognized population in follicular lymphoma (FL), which is considered to be the pathologic counterpart of germinal center B cells. Immunohistochemistry analysis with a panel of antibodies demonstrated the presence of a cell population with the peculiar GCDC phenotype in FL biopsies and a similar localization of these cells inside tumoral and reactive follicles. Therefore, we analyzed the relationships between GCDC and the other cell subsets of the tumor follicles. Some of CD4+ and CD8+ T lymphocytes present inside the follicle were found to be in close association with GCDC, suggesting a potential implication of GCDC in their activation. In addition, the distribution of GCDC inside FL and reactive follicles did not appear disrupted, in contrast to follicular dendritic cells, the other follicle dendritic cell type. Finally, we demonstrated that GCDC could be detected from FL lymph node cell suspension by flow cytometry. Taken together, these results indicate that FL development is not associated with a disappearance of GCDC or with a lack of physical interactions between GCDC and T cells inside the follicles. In addition, the fact that GCDC can be observed in FL samples by flow cytometry should allow their purification to further study their putative role in FL development and maintenance.
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Affiliation(s)
- N Renard
- Service d'Hématologie, Centre Hospitalier Lyon-Sud, Université Claude Bernard, Pierre-Benite, France
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44
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Coutinho P, Barros J, Zemmouri R, Guimarães J, Alves C, Chorão R, Lourenço E, Ribeiro P, Loureiro JL, Santos JV, Hamri A, Paternotte C, Hazan J, Silva MC, Prud'homme JF, Grid D. Clinical heterogeneity of autosomal recessive spastic paraplegias: analysis of 106 patients in 46 families. Arch Neurol 1999; 56:943-9. [PMID: 10448799 DOI: 10.1001/archneur.56.8.943] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
BACKGROUND Hereditary spastic paraplegias (HSPs) are a heterogeneous group of neurodegenerative disorders characterized by progressive and predominant spasticity of the lower limbs, in which dominant, recessive, and X-linked forms have been described. While autosomal dominant HSP has been extensively studied, autosomal recessive HSP is less well known and is considered a rare condition. OBJECTIVE To analyze the clinical presentation in a large group of patients with autosomal recessive HSP from Portugal and Algeria to define homogeneous groups that could serve as a guide for future molecular studies. RESULTS Clinical features in 106 patients belonging to 46 Portuguese and Algerian families with autosomal recessive HSP are presented, as well as the results of molecular studies in 23 of these families. Five phenotypes are defined: (1) pure early-onset families, (2) pure lateonset families, (3) complex families with mental retardation, (4) complex families with mental retardation and peripheral neuropathy, and (5) complex families with cerebellar ataxia. Six additional families have specific complex presentations, each of which is unique in the present series. Pyramidal signs in the upper limbs and pes cavus are frequent findings, while pseudobulbar signs, including dysarthria, dysphagia, and brisk jaw jerks, are more frequent in the complex forms. The complex forms have a poorer prognosis, while pure forms, particularly those with early onset, are more benign. One Algerian pure early-onset kindred was linked to the locus on chromosome 8, previously reported in 4 Tunisian families. Two of the Portuguese kindreds with complex forms (one with mental retardation and the other associated with hypoplasia of the corpus callosum) showed linkage to the locus recently identified on chromosome 16. CONCLUSIONS Although autosomal recessive HSP represents a heterogeneous group of diseases, some phenotypes can be defined by analyzing a large group of patients. The fact that only one Algerian family was linked to chromosome 8 suggests that this is a rare localization even in kindreds with the same ethnic background. Linkage to chromosome 16 was found in 2 clinically diverse Portuguese kindreds, illustrating that this locus is also rare and may correspond to different phenotypes.
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Affiliation(s)
- P Coutinho
- Department of Medicine, Hospital S. Sebastião, Santa Maria de Feira, Portugal
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Abstract
A cDNA (Schistosoma mansoni tryptophan hydroxylase; SmTPH) encoding a protein homologous to tryptophan hydroxylase, the enzyme that catalyzes the rate-limiting step in the biosynthesis of serotonin, was cloned from the human parasite Schistosoma mansoni. Bacterial expression of SmTPH as a histidine fusion protein produced soluble active enzyme, which was purified to apparent homogeneity and a final specific activity of 0.17 micromol/min/mg of protein. The purified enzyme was found to be a tetramer of approximately 240 kDa with a subunit size of 58 kDa. Several of the biochemical and kinetic properties of SmTPH were similar to those of mammalian tryptophan hydroxylase. Unlike the mammalian enzyme, however, SmTPH was found to be stable at 37 degrees C, its t((1)/(2)) being nearly 23 times higher than that of a similarly expressed rabbit tryptophan hydroxylase. A semiquantitative reverse transcription polymerase chain reaction showed that the level of SmTPH mRNA in a larval stage of the parasite (cercaria) is 2.5 times higher than in adult S. mansoni, suggesting possible differences in the level of enzyme expression between the two developmental stages. This study demonstrates for the first time the presence of a functional tryptophan hydroxylase in a parasitic helminth and further suggests that the parasites are capable of synthesizing serotonin endogenously.
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Affiliation(s)
- F F Hamdan
- Institute of Parasitology, McGill University, Quebec H9X 3V9, Canada
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Paiement JP, Leger C, Ribeiro P, Prichard RK. Haemonchus contortus: effects of glutamate, ivermectin, and moxidectin on inulin uptake activity in unselected and ivermectin-selected adults. Exp Parasitol 1999; 92:193-8. [PMID: 10403760 DOI: 10.1006/expr.1999.4413] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Using [(3)H]inulin uptake as a measure of pharyngeal pumping activity, we have investigated and compared the effects of glutamate, ivermectin, and moxidectin on inulin uptake in susceptible and ivermectin-selected Haemonchus contortus. Inulin uptake is inhibited by glutamate, ivermectin, and moxidectin, at biologically relevant concentrations. Glutamate influences the responses to both ivermectin and moxidectin, suggesting that these three substances share a common mechanism of action. The effects of ivermectin on inulin uptake, but not moxidectin, are significantly altered as a result of selection with ivermectin. These results suggest that ivermectin and moxidectin may differ, to some extent, in their mode of action responses or mechanisms of resistance.
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Affiliation(s)
- J P Paiement
- Institute of Parasitology, McGill University, 21111 Lakeshore Road, Ste-Anne-de-Bellevue, Québec, H9X 3V9, Canada
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Sousa AB, Fernandes JP, Ferreira G, Bernardo M, Conduto A, Costa I, Cruz E, Gonçalves AJ, Monteiro A, Nunes O, Ribeiro P, Rodrigues AS, Sousa M, Veiga J, Gouveia J. Short-term intensive consolidation therapy after all-trans retinoic acid in acute promyelocytic leukemia. Am J Clin Oncol 1999; 22:294-7. [PMID: 10362340 DOI: 10.1097/00000421-199906000-00017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Complete remission induced by all-trans retinoic acid (ATRA) in acute promyelocytic leukemia is short lived, and several consolidation chemotherapy courses usually are given to reduce the relapse rate. To assess the value of short-term intensive consolidation, 38 patients with newly diagnosed acute promyelocytic leukemia entered a prospective study in which induction therapy with ATRA immediately was followed by a single course of mitoxantrone plus high-dose cytarabine (3 g/m2 every 12 hours, days 1-4), with no further treatment. Complete remission was achieved in 31 patients (81.6%) after a median time of 49 days of ATRA (to which chemotherapy was added at entry in 10 patients with leukocytosis). Thirty patients received the planned consolidation course. After a median follow-up of 36 months, four of these patients have relapsed and 24 are still in first complete remission, for an estimated disease-free survival of 75% at 60 months. The authors conclude that this single course consolidation of ATRA-induced remission provides excellent long-term control of acute promyelocytic leukemia.
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Affiliation(s)
- A B Sousa
- Serviço de Hematologia, Hospital dos Capuchos, Lisbon, Portugal
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Paiement J, Prichard RK, Ribeiro P. Haemonchus contortus: characterization of a glutamate binding site in unselected and ivermectin-selected larvae and adults. Exp Parasitol 1999; 92:32-9. [PMID: 10329363 DOI: 10.1006/expr.1999.4396] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A specific ivermectin-sensitive, glutamate binding site has been identified in the parasitic nematode Haemonchus contortus. Glutamate binding in H. contortus was saturable and occurred in a single class of high-affinity binding sites which appeared to have pharmacological properties different from those of mammalian glutamate receptors. Adult and larval forms of H. contortus had dramatically different glutamate binding kinetics, the larvae showing nearly up to 200-fold higher Bmax values and up to 9-fold increases in Kd values compared to adults. Treatment of adult H. contortus with the anthelmintic, ivermectin, decreased the Bmax value for glutamate binding in the susceptible strain but not in the resistant parasites. Furthermore, selection for ivermectin resistance was associated with a significant increase in Bmax for glutamate binding in adults and a similarly significant increase in glutamate binding affinity in larvae. These results suggest that the H. contortus glutamate binding site identified in this study may be involved in the phenomenon of ivermectin resistance.
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Affiliation(s)
- J Paiement
- Institute of Parasitology, McGill University, 21 111 Lakeshore Road, Ste-Anne-de-Bellevue, Quebec, H9X 3V9, Canada
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Hamdan FF, Ungrin MD, Abramovitz M, Ribeiro P. Characterization of a novel serotonin receptor from Caenorhabditis elegans: cloning and expression of two splice variants. J Neurochem 1999; 72:1372-83. [PMID: 10098838 DOI: 10.1046/j.1471-4159.1999.721372.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Serotonin [5-hydroxytryptamine (5-HT)] modulates feeding activity, egg-laying, and mating behavior in the free-living nematode, Caenorhabditis elegans. We have cloned a novel receptor cDNA from C. elegans (5-HT2Ce) that has high sequence homology with 5-HT2 receptors from other species. When transiently expressed in COS-7 cells, 5-HT2Ce exhibited 5-HT binding activity and activated Ca2+-mediated signaling in a manner analogous to other 5-HT2 receptors. However, 5-HT2Ce displayed unusual pharmacological properties, which resembled both 5-HT2 and 5-HT1-like receptors but did not correlate well with any of the known 5-HT2 subtypes. Two splice variants of 5-HT2Ce that differ by 48 N-terminal amino acids were identified. The two isoforms were found to have virtually identical binding and signaling properties but differed in their levels of mRNA expression, with the longer variant being four times more abundant than the shorter species in all developmental stages tested. Taken together, the results describe two variants of a novel C. elegans 5-HT receptor, which has some of the properties of the 5-HT2 family but whose pharmacological profile does not conform to any known class of receptor.
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Affiliation(s)
- F F Hamdan
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Quebec, Canada
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50
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Renard N, Ribeiro P, Warzocha K, Rouvière R, Charlot C, Coiffier B, Salles G. Modulation of costimulatory molecules on follicular lymphoma cells by TNF and CD40. Leuk Lymphoma 1999; 33:331-41. [PMID: 10221513 DOI: 10.3109/10428199909058433] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
TNF has recently been implicated in the formation of germinal center cells in lymphoid organs. Follicular lymphoma (FL) is thought to represent the pathological counterpart of germinal center B-cell. High levels of TNF and its soluble receptors were found in the plasma of FL patients whereas the transcripts of these molecules were previously found to be present in FL patients lymph nodes. We therefore studied here the effects of TNF on the expression of costimulatory molecules implicated in the cytotoxic T cell response on purified FL cells. In contrast to results described with B-type chronic lymphocytic leukemia, also characterized by high levels of circulating TNF, none of the tested samples showed a regulation of CD80, CD86, CD27 and CD70 in response to TNF. To confirm that the lack of regulation of these molecules was not due to the FL cells inability to modulate their expression, we therefore analyzed costimulatory molecules expression after CD40 pathway stimulation. After culture with human CD40L-transfected L-cells, an up-regulation of CD80, CD86 and CD70 expression was observed, while TNF addition in this model did not influence these changes. In this context, the CD27 molecule was down-regulated except in a single case, where its expression was increased. Taken together, this data demonstrates that in vitro expression of costimulatory molecules such as CD80, CD86, CD27 and CD70, which are implicated in the anti-tumoral response, can be regulated by CD40 ligand but not by TNF.
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Affiliation(s)
- N Renard
- Service d'Hématologie, Centre Hospitalier Lyon-Sud, Hospices Civils de Lyon et UPRES-JE 1879 Hémopathies Lymphoïdes Malignes, Pierre-Bénite, France
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