Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 20
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
ACS Sens ; 4(4): 874-882, 2019 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-30839200

RESUMO

Recently, the co-immobilization of polyethylene glycol has improved sensor responses of transistor-based immunosensing by approximately three times. However, there is currently no analytical model available to explain this empirical effect. The key parameters thought to affect the potential are the receptor density, the capacitance, the analyte charge, and the dissociation constant. Based on our experimental data, only the analyte charge can account for the signal enhancement. To capture the effect of PEG on the analyte charge, we introduce a prefactor, the detectable charge qdet, which represents the portion of analyte charges effectively detected by the sensor. This parameter can quantitatively describe the PEG-induced signal enhancement and can be used to recommend the choice of PEG size for immuno-field-effect transistors. Additionally, we include the competition between electrolyte ions and the analyte for binding to the recognition molecule to more accurately describe the concentration-dependent sensor responses than the traditional Langmuir binding model does.

2.
Langmuir ; 34(20): 5703-5711, 2018 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-29553272

RESUMO

Respiratory complex I (CpI) is a key player in the way organisms obtain energy, being an energy transducer, which couples nicotinamide adenine dinucleotide (NADH)/quinone oxidoreduction with proton translocation by a mechanism that remains elusive so far. In this work, we monitored the function of CpI in a biomimetic, supported lipid membrane system assembled on a 4-aminothiophenol (4-ATP) self-assembled monolayer by surface-enhanced infrared absorption spectroscopy. 4-ATP serves not only as a linker molecule to a nanostructured gold surface but also as pH sensor, as indicated by concomitant density functional theory calculations. In this way, we were able to monitor NADH/quinone oxidoreduction-induced transmembrane proton translocation via the protonation state of 4-ATP, depending on the net orientation of CpI molecules induced by two complementary approaches. An associated change of the amide I/amide II band intensity ratio indicates conformational modifications upon catalysis which may involve movements of transmembrane helices or other secondary structural elements, as suggested in the literature [ Di Luca , Proc. Natl. Acad. Sci. U.S.A. , 2017 , 114 , E6314 - E6321 ].


Assuntos
Complexo I de Transporte de Elétrons/metabolismo , Prótons , Espectrofotometria Infravermelho , Catálise , Complexo I de Transporte de Elétrons/química , NAD/química , Oxirredução
3.
Plant Physiol ; 176(2): 1709-1727, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29233938

RESUMO

Body regeneration through formation of new organs is a major question in developmental biology. We investigated de novo root formation using whole leaves of Arabidopsis (Arabidopsis thaliana). Our results show that local cytokinin biosynthesis and auxin biosynthesis in the leaf blade followed by auxin long-distance transport to the petiole leads to proliferation of J0121-marked xylem-associated tissues and others through signaling of INDOLE-3-ACETIC ACID INDUCIBLE28 (IAA28), CRANE (IAA18), WOODEN LEG, and ARABIDOPSIS RESPONSE REGULATORS1 (ARR1), ARR10, and ARR12. Vasculature proliferation also involves the cell cycle regulator KIP-RELATED PROTEIN2 and ABERRANT LATERAL ROOT FORMATION4, resulting in a mass of cells with rooting competence that resembles callus formation. Endogenous callus formation precedes specification of postembryonic root founder cells, from which roots are initiated through the activity of SHORT-ROOT, PLETHORA1 (PLT1), and PLT2. Primordia initiation is blocked in shr plt1 plt2 mutant. Stem cell regulators SCHIZORIZA, JACKDAW, BLUEJAY, and SCARECROW also participate in root initiation and are required to pattern the new organ, as mutants show disorganized and reduced number of layers and tissue initials resulting in reduced rooting. Our work provides an organ regeneration model through de novo root formation, stating key stages and the primary pathways involved.


Assuntos
Arabidopsis/genética , Reprogramação Celular , Regulação da Expressão Gênica de Plantas , Ácidos Indolacéticos/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Transdução de Sinais , Arabidopsis/crescimento & desenvolvimento , Regulação da Expressão Gênica no Desenvolvimento , Modelos Biológicos , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Regeneração
4.
ACS Sens ; 2(9): 1278-1286, 2017 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-28853283

RESUMO

Transistor-based biosensors fulfill many requirements posed upon transducers for future point-of-care diagnostic devices such as scalable fabrication and label-free and real-time quantification of chemical and biological species with high sensitivity. However, the short Debye screening length in physiological samples (<1 nm) has been a major drawback so far, preventing direct measurements in serum. In this work, we demonstrate how tailoring the sensing surface with short specific biological receptors and a polymer polyethylene glycol (PEG) can strongly enhance the sensor response. In addition, the sensor performance can be dramatically improved if the measurements are performed at elevated temperatures (37 °C instead of 21 °C). With this novel approach, highly sensitive and selective detection of a representative immunosensing parameter-human thyroid-stimulating hormone-is shown over a wide measuring range with subpicomolar detection limits in whole serum. To the best of our knowledge, this is the first demonstration of direct immunodetection in whole serum using transistor-based biosensors, without the need for sample pretreatment, labeling, or washing steps. The presented sensor is low-cost, can be easily integrated into portable diagnostics devices, and offers a competitive performance compared to state-of-the-art central laboratory analyzers.

5.
Crit Rev Oncol Hematol ; 113: 83-89, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28427527

RESUMO

BACKGROUND: Cancer patients are at high risk of venous thromboembolism, particularly during cancer treatment. Conversely to chemotherapy, data on the epidemiology and clinical features of venous thromboembolism during radiation therapy are scarce. There is lack of evidence on the influence of radiation therapy (RT) on outcome in cancer patients with acute venous thromboembolism (VTE). METHODS: We used the RIETE (Registro Informatizado de Enfermedad ThromboEmbolica) database to assess the clinical characteristics and outcome of prospectively-collected consecutive patients with cancer-associated thrombosis occurred during the course of radiation therapy for cancer. Death, venous thromboembolism recurrences and major bleeding rates during long-term follow-up according to cancer site and treatment were compared RESULTS: 9284 Patients with active cancer and VTE were enrolled in RIETE: 4605 with pulmonary embolism (PE) and 4679 with deep vein thrombosis (DVT). In all, 1202 (13%) were receiving RT. This last sub-population had a higher rate of PE recurrences and a similar rate of DVT recurrences or major bleeding than those not receiving RT. Patients on RT had a higher rate of cerebral bleeding. CONCLUSIONS: In this cohort of cancer patients with VTE, a significant proportion of them received RT before VTE, the latter experienced a higher risk of cerebral bleeding.


Assuntos
Neoplasias/radioterapia , Sistema de Registros , Tromboembolia Venosa/etiologia , Idoso , Feminino , Hemorragia/epidemiologia , Hemorragia/etiologia , Hemorragia/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias/complicações , Estudos Prospectivos , Embolia Pulmonar/epidemiologia , Embolia Pulmonar/etiologia , Embolia Pulmonar/patologia , Radioterapia/efeitos adversos , Radioterapia/mortalidade , Recidiva , Tromboembolia Venosa/epidemiologia , Tromboembolia Venosa/patologia , Trombose Venosa/epidemiologia , Trombose Venosa/etiologia , Trombose Venosa/patologia
6.
Nat Chem Biol ; 13(5): 544-550, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28319099

RESUMO

Hydrogenases are highly active enzymes for hydrogen production and oxidation. [NiFeSe] hydrogenases, in which selenocysteine is a ligand to the active site Ni, have high catalytic activity and a bias for H2 production. In contrast to [NiFe] hydrogenases, they display reduced H2 inhibition and are rapidly reactivated after contact with oxygen. Here we report an expression system for production of recombinant [NiFeSe] hydrogenase from Desulfovibrio vulgaris Hildenborough and study of a selenocysteine-to-cysteine variant (Sec489Cys) in which, for the first time, a [NiFeSe] hydrogenase was converted to a [NiFe] type. This modification led to severely reduced Ni incorporation, revealing the direct involvement of this residue in the maturation process. The Ni-depleted protein could be partly reconstituted to generate an enzyme showing much lower activity and inactive states characteristic of [NiFe] hydrogenases. The Ni-Sec489Cys variant shows that selenium has a crucial role in protection against oxidative damage and the high catalytic activities of the [NiFeSe] hydrogenases.


Assuntos
Biocatálise , Desulfovibrio vulgaris/enzimologia , Hidrogenase/química , Hidrogenase/metabolismo , Selenocisteína/metabolismo , Desulfovibrio vulgaris/metabolismo , Ligantes , Modelos Moleculares , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Selenocisteína/química
7.
Angew Chem Int Ed Engl ; 55(21): 6216-20, 2016 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-26991333

RESUMO

ATP, the molecule used by living organisms to supply energy to many different metabolic processes, is synthesized mostly by the ATPase synthase using a proton or sodium gradient generated across a lipid membrane. We present evidence that a modified electrode surface integrating a NiFeSe hydrogenase and a F1 F0 -ATPase in a lipid membrane can couple the electrochemical oxidation of H2 to the synthesis of ATP. This electrode-assisted conversion of H2 gas into ATP could serve to generate this biochemical fuel locally when required in biomedical devices or enzymatic synthesis of valuable products.


Assuntos
Trifosfato de Adenosina/metabolismo , Hidrogênio/química , Técnicas Eletroquímicas , Eletrodos , Hidrogênio/metabolismo , Hidrogenase/química , Hidrogenase/metabolismo , Bicamadas Lipídicas/química , Microscopia de Força Atômica , ATPases Mitocondriais Próton-Translocadoras/química , ATPases Mitocondriais Próton-Translocadoras/metabolismo , Oxirredução , Técnicas de Microbalança de Cristal de Quartzo
9.
J Biol Chem ; 290(13): 8550-8, 2015 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-25666617

RESUMO

The heterodimeric [NiFe] hydrogenase from Desulfovibrio fructosovorans catalyzes the reversible oxidation of H2 into protons and electrons. The catalytic intermediates have been attributed to forms of the active site (NiSI, NiR, and NiC) detected using spectroscopic methods under potentiometric but non-catalytic conditions. Here, we produced variants by replacing the conserved Thr-18 residue in the small subunit with Ser, Val, Gln, Gly, or Asp, and we analyzed the effects of these mutations on the kinetic (H2 oxidation, H2 production, and H/D exchange), spectroscopic (IR, EPR), and structural properties of the enzyme. The mutations disrupt the H-bond network in the crystals and have a strong effect on H2 oxidation and H2 production turnover rates. However, the absence of correlation between activity and rate of H/D exchange in the series of variants suggests that the alcoholic group of Thr-18 is not necessarily a proton relay. Instead, the correlation between H2 oxidation and production activity and the detection of the NiC species in reduced samples confirms that NiC is a catalytic intermediate and suggests that Thr-18 is important to stabilize the local protein structure of the active site ensuring fast NiSI-NiC-NiR interconversions during H2 oxidation/production.


Assuntos
Proteínas de Bactérias/química , Desulfovibrio/enzimologia , Hidrogenase/química , Sequência de Aminoácidos , Substituição de Aminoácidos , Biocatálise , Domínio Catalítico , Cristalografia por Raios X , Estabilidade Enzimática , Ligações de Hidrogênio , Cinética , Modelos Moleculares , Oxirredução , Treonina/química
10.
Angew Chem Int Ed Engl ; 54(9): 2684-7, 2015 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-25600156

RESUMO

Energy-transduction mechanisms in living organisms, such as photosynthesis and respiration, store light and chemical energy in the form of an electrochemical gradient created across a lipid bilayer. Herein we show that the proton concentration at an electrode/phospholipid-bilayer interface can be controlled and monitored electrochemically by immobilizing a membrane-bound hydrogenase. Thus, the energy derived from the electroenzymatic oxidation of H2 can be used to generate a proton gradient across the supported biomimetic membrane.


Assuntos
Materiais Biomiméticos/metabolismo , Técnicas Eletroquímicas , Ouro/química , Hidrogênio/metabolismo , Hidrogenase/metabolismo , Prótons , Materiais Biomiméticos/química , Eletrodos , Hidrogênio/química , Hidrogenase/química , Bicamadas Lipídicas/química , Bicamadas Lipídicas/metabolismo , Oxirredução , Fosfolipídeos/química , Fosfolipídeos/metabolismo
11.
J Biol Inorg Chem ; 20(1): 11-22, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25315838

RESUMO

Catalytically inactive oxidized O2-sensitive [NiFe]-hydrogenases are characterized by a mixture of the paramagnetic Ni-A and Ni-B states. Upon O2 exposure, enzymes in a partially reduced state preferentially form the unready Ni-A state. Because partial O2 reduction should generate a peroxide intermediate, this species was previously assigned to the elongated Ni-Fe bridging electron density observed for preparations of [NiFe]-hydrogenases known to contain the Ni-A state. However, this proposition has been challenged based on the stability of this state to UV light exposure and the possibility of generating it anaerobically under either chemical or electrochemical oxidizing conditions. Consequently, we have considered alternative structures for the Ni-A species including oxidation of thiolate ligands to either sulfenate or sulfenic acid. Here, we report both new and revised [NiFe]-hydrogenases structures and conclude, taking into account corresponding characterizations by Fourier transform infrared spectroscopy (FTIR), that the Ni-A species contains oxidized cysteine and bridging hydroxide ligands instead of the peroxide ligand we proposed earlier. Our analysis was rendered difficult by the typical formation of mixtures of unready oxidized states that, furthermore, can be reduced by X-ray induced photoelectrons. The present study could be carried out thanks to the use of Desulfovibrio fructosovorans [NiFe]-hydrogenase mutants with special properties. In addition to the Ni-A state, crystallographic results are also reported for two diamagnetic unready states, allowing the proposal of a revised oxidized inactive Ni-SU model and a new structure characterized by a persulfide ion that is assigned to an Ni-'Sox' species.


Assuntos
Proteínas de Bactérias/química , Hidrogenase/química , Methylophilaceae/enzimologia , Substituição de Aminoácidos , Proteínas de Bactérias/genética , Domínio Catalítico , Cristalografia por Raios X , Hidrogenase/genética , Ferro/química , Modelos Moleculares , Níquel/química , Oxirredução , Espectroscopia de Infravermelho com Transformada de Fourier
12.
Langmuir ; 30(29): 9007-15, 2014 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-24988043

RESUMO

For the first time, respiratory complex I has been reconstituted on an electrode preserving its structure and activity. Respiratory complex I is a membrane-bound enzyme that has an essential function in cellular energy production. It couples NADH:quinone oxidoreduction to translocation of ions across the cellular (in prokaryotes) or mitochondrial membranes. Therefore, complex I contributes to the establishment and maintenance of the transmembrane difference of electrochemical potential required for adenosine triphosphate synthesis, transport, and motility. Our new strategy has been applied for reconstituting the bacterial complex I from Rhodothermus marinus onto a biomimetic membrane supported on gold electrodes modified with a thiol self-assembled monolayer (SAM). Atomic force microscopy and faradaic impedance measurements give evidence of the biomimetic construction, whereas electrochemical measurements show its functionality. Both electron transfer and proton translocation by respiratory complex I were monitored, simulating in vivo conditions.


Assuntos
Proteínas de Bactérias/química , Complexo I de Transporte de Elétrons/química , Ouro/química , Prótons , Rhodothermus/química , Proteínas de Bactérias/isolamento & purificação , Materiais Biomiméticos , Eletrodos , Transporte de Elétrons , Complexo I de Transporte de Elétrons/isolamento & purificação , Membranas Artificiais , Microscopia de Força Atômica , Rhodothermus/enzimologia , Reagentes de Sulfidrila/química
13.
Methods Mol Biol ; 1122: 95-106, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24639255

RESUMO

Absorption of infrared radiation by proteins gives important information about their structure and function. The most intense infrared bands correspond to the overlap of all the peptide bond absorption. Additionally, in many metalloproteins their prosthetic groups have intrinsic ligands or bind substrates/inhibitors that absorb intensively in the infrared. Here, we describe thoroughly several Fourier transform infrared methods for studying structure-function relationships in metalloproteins, using hydrogenases as an example.


Assuntos
Metaloproteínas/análise , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Trifosfato de Adenosina/farmacologia , Desulfovibrio/enzimologia , Hidrogenase/metabolismo , Proteínas Imobilizadas/metabolismo , Ralstonia/enzimologia
14.
Eur J Haematol ; 91(3): 236-41, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23679653

RESUMO

AIM: Few studies specifically focus on elderly splenectomized immune thrombocytopenia (ITP) patients. Older patients with ITP and excellent health are often excluded from surgery splenectomy. We aimed to compare the safety and efficacy of splenectomy in elderly and non-elderly ITP patients and to examine the effect of age on therapeutic response. MATERIAL AND METHODS: We carried out a retrospective analysis of a series of 218 patients who had undergone splenectomy for ITP. We compared the data from the elderly group (≥65 yrs, 57 patients) with the young group (<65 yrs, 162 patients). RESULTS: Surgical technique (laparoscopy or open laparotomy splenectomy) was comparable between the two age groups. The adjusted risk of major bleeding following splenectomy for elderly patients was three times that for young patients (OR 3.05, 95% CI: 1.44-6.52). The median duration of postoperative hospital stay was longer for elderly than for young patients (8 d vs. 4 d, P < 0.001). However, we identified a subgroup of elderly ITP patients, those aged between 65 and 70 yrs who had undergone laparoscopic splenectomy, with a low risk of postoperative complications. Of the 218 patients, 89% achieved a favorable response to splenectomy. A favorable response was significantly less common in elderly than in young people (79% vs. 92%, P = 0.005). However, we observed an acceptable long-term control of ITP in the elderly group, in which the probability of maintaining response for 14 yrs after splenectomy was 56%. CONCLUSIONS: Patients aged ≥65 yrs experienced negative effects on safety and efficacy outcomes of splenectomy for ITP, but further studies are needed to identify predictors of postsplenectomy outcomes in this group.


Assuntos
Púrpura Trombocitopênica Idiopática/cirurgia , Esplenectomia , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias , Púrpura Trombocitopênica Idiopática/complicações , Púrpura Trombocitopênica Idiopática/mortalidade , Estudos Retrospectivos , Fatores de Risco , Esplenectomia/efeitos adversos , Resultado do Tratamento
15.
J Biol Inorg Chem ; 18(4): 419-27, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23468234

RESUMO

A combined experimental and theoretical study of the catalytic activity of a [NiFeSe] hydrogenase has been performed by H/D exchange mass spectrometry and molecular dynamics simulations. Hydrogenases are enzymes that catalyze the heterolytic cleavage or production of H2. The [NiFeSe] hydrogenases belong to a subgroup of the [NiFe] enzymes in which a selenocysteine is a ligand of the nickel atom in the active site instead of cysteine. The aim of this research is to determine how much the specific catalytic properties of this hydrogenase are influenced by the replacement of a sulfur by selenium in the coordination of the bimetallic active site versus the changes in the protein structure surrounding the active site. The pH dependence of the D2/H(+) exchange activity and the high isotope effect observed in the Michaelis constant for the dihydrogen substrate and in the single exchange/double exchange ratio suggest that a "cage effect" due to the protein structure surrounding the active site is modulating the enzymatic catalysis. This "cage effect" is supported by molecular dynamics simulations of the diffusion of H2 and D2 from the outside to the inside of the protein, which show different accumulation of these substrates in a cavity next to the active site.


Assuntos
Hidrogenase/química , Simulação de Dinâmica Molecular , Domínio Catalítico , Conformação Proteica , Enxofre/química
16.
Nat Chem Biol ; 9(1): 15-7, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23143415

RESUMO

We studied the mechanism of aerobic inactivation of Desulfovibrio fructosovorans nickel-iron (NiFe) hydrogenase by quantitatively examining the results of electrochemistry, EPR and FTIR experiments. They suggest that, contrary to the commonly accepted mechanism, the attacking O(2) is not incorporated as an active site ligand but, rather, acts as an electron acceptor. Our findings offer new ways toward the understanding of O(2) inactivation and O(2) tolerance in NiFe hydrogenases.


Assuntos
Hidrogenase/metabolismo , Oxigênio/metabolismo , Desulfovibrio/enzimologia , Técnicas Eletroquímicas , Espectroscopia de Ressonância de Spin Eletrônica , Hidrogenase/química , Espectroscopia de Infravermelho com Transformada de Fourier
17.
Proc Natl Acad Sci U S A ; 109(49): 19916-21, 2012 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-23169623

RESUMO

Nickel-containing hydrogenases, the biological catalysts of oxidation and production, reversibly inactivate under anaerobic, oxidizing conditions. We aim at understanding the mechanism of (in)activation and what determines its kinetics, because there is a correlation between fast reductive reactivation and oxygen tolerance, a property of some hydrogenases that is very desirable from the point of view of biotechnology. Direct electrochemistry is potentially very useful for learning about the redox-dependent conversions between active and inactive forms of hydrogenase, but the voltammetric signals are complex and often misread. Here we describe simple analytical models that we used to characterize and compare 16 mutants, obtained by substituting the position-74 valine of the -sensitive NiFe hydrogenase from Desulfovibrio fructosovorans. We observed that this substitution can accelerate reactivation up to 1,000-fold, depending on the polarity of the position 74 amino acid side chain. In terms of kinetics of anaerobic (in)activation and oxygen tolerance, the valine-to-histidine mutation has the most spectacular effect: The V74H mutant compares favorably with the -tolerant hydrogenase from Aquifex aeolicus, which we use here as a benchmark.


Assuntos
Biotecnologia/métodos , Desulfovibrio/enzimologia , Ativação Enzimática/genética , Hidrogenase/genética , Hidrogenase/metabolismo , Modelos Biológicos , Substituição de Aminoácidos/genética , Anaerobiose , Ativação Enzimática/fisiologia , Cinética , Mutação de Sentido Incorreto/genética , Oxirredução
18.
J Am Chem Soc ; 134(20): 8368-71, 2012 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-22540997

RESUMO

When enzymes are optimized for biotechnological purposes, the goal often is to increase stability or catalytic efficiency. However, many enzymes reversibly convert their substrate and product, and if one is interested in catalysis in only one direction, it may be necessary to prevent the reverse reaction. In other cases, reversibility may be advantageous because only an enzyme that can operate in both directions can turnover at a high rate even under conditions of low thermodynamic driving force. Therefore, understanding the basic mechanisms of reversibility in complex enzymes should help the rational engineering of these proteins. Here, we focus on NiFe hydrogenase, an enzyme that catalyzes H(2) oxidation and production, and we elucidate the mechanism that governs the catalytic bias (the ratio of maximal rates in the two directions). Unexpectedly, we found that this bias is not mainly determined by redox properties of the active site, but rather by steps which occur on sites of the proteins that are remote from the active site. We evidence a novel strategy for tuning the catalytic bias of an oxidoreductase, which consists in modulating the rate of a step that is limiting only in one direction of the reaction, without modifying the properties of the active site.


Assuntos
Desulfovibrio/enzimologia , Hidrogenase/metabolismo , Domínio Catalítico , Desulfovibrio/química , Desulfovibrio/genética , Hidrogenase/química , Hidrogenase/genética , Modelos Moleculares , Mutação , Oxirredução , Termodinâmica
20.
Pacing Clin Electrophysiol ; 25(5): 871-2, 2002 May.
Artigo em Inglês | MEDLINE | ID: mdl-12049386

RESUMO

Treatment of paroxysmal atrial fibrillation with flecainide acetate resulted in a 4-fold increase in ventricular capture thresholds. The detailed time course of the threshold increase and decrease was documented using the AutoCapture algorithm and graphic summary.


Assuntos
Antiarrítmicos/efeitos adversos , Fibrilação Atrial/terapia , Flecainida/efeitos adversos , Ventrículos do Coração/fisiopatologia , Marca-Passo Artificial , Idoso , Antiarrítmicos/uso terapêutico , Fibrilação Atrial/fisiopatologia , Falha de Equipamento , Flecainida/uso terapêutico , Humanos , Masculino
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA