Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 19 de 19
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Ann Med Surg (Lond) ; 84: 104812, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36536727

RESUMO

Objectives: To determine whether surgical technique has an effect on prognosis in coronary artery bypass grafting (CABG). Design: Retrospective observational. Setting: Single center. Participants: All the off-pump (OPCABG) and on-pump (ONCABG) patients at Turku University Central Hospital in 2018. Interventions: None. Measurements and main results: After propensity score matching, perioperative, 1-year and 3-year mortality did not differ between the groups. The ONCABG patients received more allogenic red blood cells (1.3 vs. 0.6 units, p = 0.020), autologous red blood cells (564 vs. 285 ml, p < 0.001) and crystalloids (3388 vs. 2808 ml, p < 0.001), and had higher postoperative values of troponin T (581 vs. 222, p = 0.001) and lactate (1.69 vs. 1.23, p < 0.001) than the OPCABG patients. Conclusions: The both techniques seem equally safe. However, there may be some benefits to avoiding using a heart-lung machine, such as lower infused fluid volumes. Myocardial damage may also be milder and postoperative hemodynamics more balanced in OPCABG patients, based on lower levels of troponin T and lactate.

2.
Materials (Basel) ; 14(18)2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34576360

RESUMO

Chemical modification of cellulose offers routes for structurally and functionally diverse biopolymer derivatives for numerous industrial applications. Among cellulose derivatives, cellulose ethers have found extensive use, such as emulsifiers, in food industries and biotechnology. Methylcellulose, one of the simplest cellulose derivatives, has been utilized for biomedical, construction materials and cell culture applications. Its improved water solubility, thermoresponsive gelation, and the ability to act as a matrix for various dopants also offer routes for cellulose-based functional materials. There has been a renewed interest in understanding the structural, mechanical, and optical properties of methylcellulose and its composites. This review focuses on the recent development in optically and mechanically tunable hydrogels derived from methylcellulose and methylcellulose-cellulose nanocrystal composites. We further discuss the application of the gels for preparing highly ductile and strong fibers. Finally, the emerging application of methylcellulose-based fibers as optical fibers and their application potentials are discussed.

3.
PLoS One ; 16(6): e0252626, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34097713

RESUMO

BACKGROUND: Spinal fusion surgery causes severe pain. Strong opioids, commonly used as postoperative analgesics, may have unwanted side effects. S-ketamine may be an effective analgesic adjuvant in opioid patient-controlled analgesia (PCA). However, the optimal adjunct S-ketamine dose to reduce postoperative opioid consumption is still unknown. METHODS: We randomized 107 patients at two tertiary hospitals in a double-blinded, placebo-controlled clinical trial of adults undergoing major lumbar spinal fusion surgery. Patients were randomly allocated to four groups in order to compare the effects of three different doses of adjunct S-ketamine (0.25, 0.5, and 0.75 mg ml-1) or placebo on postoperative analgesia in oxycodone PCA. Study drugs were administered for 24 hours postoperative after which oxycodone-PCA was continued for further 48 hours. Our primary outcome was cumulative oxycodone consumption at 24 hours after surgery. RESULTS: Of the 100 patients analyzed, patients receiving 0.75 mg ml-1 S-ketamine in oxycodone PCA needed 25% less oxycodone at 24 h postoperatively (61.2 mg) compared with patients receiving 0.5 mg ml-1 (74.7 mg) or 0.25 mg ml-1 (74.1 mg) S-ketamine in oxycodone or oxycodone alone (81.9 mg) (mean difference: -20.6 mg; 95% confidence interval [CI]: -41 to -0.20; P = 0.048). A beneficial effect in mean change of pain intensity at rest was seen in the group receiving 0.75 mg ml-1 S-ketamine in oxycodone PCA compared with patients receiving lower ketamine doses or oxycodone alone (standardized effect size: 0.17, 95% CI: 0.013-0.32, P = 0.033). The occurrence of adverse events was similar among the groups. CONCLUSIONS: Oxycodone PCA containing S-ketamine as an adjunct at a ratio of 1: 0.75 decreased cumulative oxycodone consumption at 24 h after major lumbar spinal fusion surgery without additional adverse effects.


Assuntos
Analgesia Controlada pelo Paciente/métodos , Ketamina/uso terapêutico , Vértebras Lombares/cirurgia , Oxicodona/uso terapêutico , Fusão Vertebral/métodos , Adulto , Idoso , Analgésicos/administração & dosagem , Analgésicos/uso terapêutico , Analgésicos Opioides/administração & dosagem , Analgésicos Opioides/uso terapêutico , Relação Dose-Resposta a Droga , Método Duplo-Cego , Esquema de Medicação , Feminino , Humanos , Ketamina/administração & dosagem , Região Lombossacral , Masculino , Pessoa de Meia-Idade , Avaliação de Resultados em Cuidados de Saúde/métodos , Avaliação de Resultados em Cuidados de Saúde/estatística & dados numéricos , Oxicodona/administração & dosagem , Medição da Dor/métodos , Dor Pós-Operatória/etiologia , Dor Pós-Operatória/prevenção & controle , Fusão Vertebral/efeitos adversos
4.
J Perioper Pract ; 31(9): 326-333, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33427064

RESUMO

Since 2013, rotational thromboelastometry has been available in our hospital to assess coagulopathy. The aim of the study was to retrospectively evaluate the effect of thromboelastometry testing in cardiac surgery patients. Altogether 177 patients from 2012 and 177 patients from 2014 were included. In 2014, the thromboelastometry testing was performed on 56 patients. The mean blood drainage volume decreased and the number of patients receiving platelets decreased between 2012 and 2014. In addition, the use of fresh frozen plasma units decreased, and the use of prothrombin complex concentrate increased in 2014. When studied separately, the patients with a thromboelastometry testing received platelets, fresh frozen plasma, fibrinogen and prothrombin complex concentrate more often, but smaller amounts of red blood cells. In conclusion, after implementing the thromboelastometry testing to the practice, the blood products were given more cautiously overall. The use of thromboelastometry testing was associated with increased possibility to receive coagulation product transfusions. However, it appears that thromboelastometry testing was mostly used to assist in management of major bleeding.


Assuntos
Procedimentos Cirúrgicos Cardíacos , Tromboelastografia , Coagulação Sanguínea , Humanos , Plasma , Estudos Retrospectivos
5.
Small ; 17(27): e2005205, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33491913

RESUMO

Because of their lightweight structure, flexibility, and immunity to electromagnetic interference, polymer optical fibers (POFs) are used in numerous short-distance applications. Notably, the incorporation of luminescent nanomaterials in POFs offers optical amplification and sensing for advanced nanophotonics. However, conventional POFs suffer from nonsustainable components and processes. Furthermore, the traditionally used luminescent nanomaterials undergo photobleaching, oxidation, and they can be cytotoxic. Therefore, biopolymer-based optical fibers containing nontoxic luminescent nanomaterials are needed, with efficient and environmentally acceptable extrusion methods. Here, such an approach for fibers wet-spun from aqueous methylcellulose (MC) dispersions under ambient conditions is demonstrated. Further, the addition of either luminescent gold nanoclusters, rod-like cellulose nanocrystals or gold nanocluster-cellulose nanocrystal hybrids into the MC matrix furnishes strong and ductile composite fibers. Using cutback attenuation measurement, it is shown that the resulting fibers can act as short-distance optical fibers with a propagation loss as low as 1.47 dB cm-1 . The optical performance is on par with or even better than some of the previously reported biopolymeric optical fibers. The combination of excellent mechanical properties (Young's modulus and maximum strain values up to 8.4 GPa and 52%, respectively), low attenuation coefficient, and high photostability makes the MC-based composite fibers excellent candidates for multifunctional optical fibers and sensors.


Assuntos
Ouro , Metilcelulose , Celulose , Módulo de Elasticidade , Fibras Ópticas
6.
Biomacromolecules ; 21(2): 830-838, 2020 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-31940433

RESUMO

We show ionically cross-linked, temperature-responsive reversible or irreversible hydrogels of anionic cellulose nanocrystals (CNCs) and methacrylate terpolymers by mixing them homogeneously in the initially charge-neutral state of the polymer, which was subsequently switched to be cationic by cleaving side groups by UV irradiation. The polymer is a random terpolymer poly(di(ethylene glycol) methyl ether methacrylate)-rnd-poly(oligo(ethylene glycol) methyl ether methacrylate)-rnd-poly(2-((2-nitrobenzyl)oxycarbonyl)aminoethyl methacrylate), that is, PDEGMA-rnd-POEGMA-rnd-PNBOCAEMA. The PDEGMA and POEGMA repeating units lead to a lower critical solution temperature (LCST) behavior. Initially, homogeneous aqueous mixtures are obtained with CNCs, and no gelation is observed even upon heating to 60 °C. However, upon UV irradiation, the NBOCAEMAs are transformed to cationic 2-aminoethyl methacrylate (AEMA) groups, as 2-nitrobenzaldehyde moieties are cleaved. The resulting mixtures of anionic CNC and cationic PDEGMA-rnd-POEGMA-rnd-PAEMA show gelation for sufficiently high polymer fractions upon heating to 60 °C due to the interplay of ionic interactions and LCST. For short heating times, the gelation is thermoreversible, whereas for long enough heating times, irreversible gels can be obtained, indicating importance of kinetic aspects. The ionic nature of the cross-linking is directly shown by adding NaCl, which leads to gel melting. In conclusion, the optical triggering of the polymer ionic interactions in combination with its LCST phase behavior allows a new way for ionic nanocellulose hydrogel assemblies.


Assuntos
Celulose/efeitos da radiação , Hidrogéis/efeitos da radiação , Nanopartículas/efeitos da radiação , Raios Ultravioleta , Celulose/química , Cromatografia em Gel/métodos , Difusão Dinâmica da Luz/métodos , Hidrogéis/química , Nanopartículas/química , Temperatura
7.
Chem Commun (Camb) ; 55(78): 11739-11742, 2019 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-31513178

RESUMO

We synthesized permethylated maltoheptaose oligosaccharides, whose both ends, untrivially, have been functionalized with supramolecular binders 2-ureido-4[1H]-pyrimidinones (UPy) after single ring-opening of ß-cyclodextrin counterpart. In 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), they show lyotropic liquid crystallinity. In the dried state they allow linear saccharide-based supramolecular polymers by UPy-dimerization.

8.
Ultrasound Med Biol ; 45(2): 568-578, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30467033

RESUMO

We evaluated the relationships between regional myocardial strain measured by speckle tracking echocardiography and viability, fibrosis, hypertrophy and oxygen consumption in the infarcted or remote myocardium in a pig model of chronic myocardial infarction (MI). Thirteen farm pigs with surgical occlusion of the left anterior descending coronary artery and five sham-operated pigs were studied 3 mo post-MI. Computed tomography revealed significant left ventricle remodeling. Reduced radial or circumferential strain identified areas of transmural infarction (area under the curve: 0.82 and 0.79, respectively). In the remote non-infarcted area, radial strain correlated inversely with the amount of fibrosis (r = -0.66, p = 0.04) and myocyte hypertrophy (r = -0.68, p = 0.03). Radial strain rate inversely correlated with myocardial resting oxygen consumption assessed with 11C-labeled acetate positron emission tomography (r = -0.71, p = 0.006). In conclusion, myocardial strain and strain rate reflect fibrosis, hypertrophy and oxygen consumption of the remote areas after MI.


Assuntos
Ecocardiografia/métodos , Coração/diagnóstico por imagem , Coração/fisiopatologia , Infarto do Miocárdio/diagnóstico por imagem , Infarto do Miocárdio/fisiopatologia , Animais , Doença Crônica , Modelos Animais de Doenças , Masculino , Suínos
9.
Biomacromolecules ; 19(7): 2795-2804, 2018 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-29733648

RESUMO

We show that composite hydrogels comprising methyl cellulose (MC) and cellulose nanocrystal (CNC) colloidal rods display a reversible and enhanced rheological storage modulus and optical birefringence upon heating, i.e., inverse thermoreversibility. Dynamic rheology, quantitative polarized optical microscopy, isothermal titration calorimetry (ITC), circular dichroism (CD), and scanning and transmission electron microscopy (SEM and TEM) were used for characterization. The concentration of CNCs in aqueous media was varied up to 3.5 wt % (i.e, keeping the concentration below the critical aq concentration) while maintaining the MC aq concentration at 1.0 wt %. At 20 °C, MC/CNC underwent gelation upon passing the CNC concentration of 1.5 wt %. At this point, the storage modulus ( G') reached a plateau, and the birefringence underwent a stepwise increase, thus suggesting a percolative phenomenon. The storage modulus ( G') of the composite gels was an order of magnitude higher at 60 °C compared to that at 20 °C. ITC results suggested that, at 60 °C, the CNC rods were entropically driven to interact with MC chains, which according to recent studies collapse at this temperature into ring-like, colloidal-scale persistent fibrils with hollow cross-sections. Consequently, the tendency of the MC to form more persistent aggregates promotes the interactions between the CNC chiral aggregates towards enhanced storage modulus and birefringence. At room temperature, ITC shows enthalpic binding between CNCs and MC with the latter comprising aqueous, molecularly dispersed polymer chains that lead to looser and less birefringent material. TEM, SEM, and CD indicate CNC chiral fragments within a MC/CNC composite gel. Thus, MC/CNC hybrid networks offer materials with tunable rheological properties and access to liquid crystalline properties at low CNC concentrations.


Assuntos
Hidrogéis/química , Metilcelulose/química , Nanopartículas/química , Birrefringência , Elasticidade
10.
Nat Commun ; 8(1): 671, 2017 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-28939801

RESUMO

Material properties depend critically on the packing and order of constituent units throughout length scales. Beyond classically explored molecular self-assembly, structure formation in the nanoparticle and colloidal length scales have recently been actively explored for new functions. Structure of colloidal assemblies depends strongly on the assembly process, and higher structural control can be reliably achieved only if the process is deterministic. Here we show that self-assembly of cationic spherical metal nanoparticles and anionic rod-like viruses yields well-defined binary superlattice wires. The superlattice structures are explained by a cooperative assembly pathway that proceeds in a zipper-like manner after nucleation. Curiously, the formed superstructure shows right-handed helical twisting due to the right-handed structure of the virus. This leads to structure-dependent chiral plasmonic function of the material. The work highlights the importance of well-defined colloidal units when pursuing unforeseen and complex assemblies.Colloidal self-assembly is a unique method to produce three-dimensional materials with well-defined hierarchical structures and functionalities. Liljeström et al. show controlled preparation of macroscopic chiral wires with helical plasmonic superlattice structure composed of metal nanoparticles and viruses.


Assuntos
Ouro/química , Nanopartículas Metálicas/química , Nanofios/química , Proteínas Virais/química , Coloides/química , Nanopartículas Metálicas/ultraestrutura , Microscopia Eletrônica de Transmissão , Modelos Moleculares , Nanotubos/química , Nanotubos/ultraestrutura , Nanofios/ultraestrutura , Tamanho da Partícula , Espalhamento a Baixo Ângulo , Vírus do Mosaico do Tabaco/química , Vírus do Mosaico do Tabaco/ultraestrutura , Proteínas Virais/ultraestrutura , Difração de Raios X
11.
Biomacromolecules ; 18(4): 1293-1301, 2017 04 10.
Artigo em Inglês | MEDLINE | ID: mdl-28262019

RESUMO

Fiber spinning of anionic TEMPO-oxidized cellulose (TOCN) nanofibrils with polycations by interfacial polyelectrolyte complexation is demonstrated. The formed fibers were mostly composed of cellulose nanofibrils and the polycations were a minor constituent, leading to yield and ultimate strengths of ca. 100 MPa and ca. 200 MPa, and Young's modulus of ca. 15 GPa. Stretching of the as-formed wet filaments of TOCN/polycation by 20% increased the Young's modulus, yield strength, and ultimate tensile strength by approximately 45, 36, and 26%, respectively. Importantly, feasibility of compartmentalized wound bicomponent fibers by simultaneous spinning of two fibers of different compositions and entwining them together was shown. This possibility was further exploited to demonstrate reversible shape change of a bicomponent fiber directly by humidity change, and indirectly by temperature changes based on thermally dependent humidity absorption. The demonstrated route for TOCN-based fiber preparation is expected to open up new avenues in the application of nanocelluloses in advanced fibrous materials, crimping, and responsive smart textiles.


Assuntos
Celulose Oxidada/química , Óxidos N-Cíclicos/química , Nanofibras/química , Polieletrólitos/química , Polietilenos/química , Compostos de Amônio Quaternário/química , Módulo de Elasticidade , Fenômenos Mecânicos , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Nanofibras/ultraestrutura , Reologia , Propriedades de Superfície , Resistência à Tração
12.
Biomaterials ; 121: 97-108, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-28081462

RESUMO

Currently, nanosystems have been developed and applied as promising vehicles for different biomedical applications. We have developed three lignin nanoparticles (LNPs): pure lignin nanoparticles (pLNPs), iron(III)-complexed lignin nanoparticles (Fe-LNPs), and Fe3O4-infused lignin nanoparticles (Fe3O4-LNPs) with round shape, narrow size distribution, reduced polydispersity and good stability at pH 7.4. The LNPs showed low cytotoxicity in all the tested cell lines and hemolytic rates below 12% after 12 h of incubation. Additionally, they induced hydrogen peroxide production in a small extent and time-dependent manner, and the interaction with the cells increased over time, exhibiting a dose-dependent cell uptake. Concerning the drug loading, pLNPs showed the capacity to efficiently load poorly water-soluble drugs and other cytotoxic agents, e.g. sorafenib and benzazulene (BZL), and improve their release profiles at pH 5.5 and 7.4 in a sustained manner. Furthermore, the BZL-pLNPs presented an enhanced antiproliferation effect in different cells compared to the pure BZL and showed a maximal inhibitory concentration ranging from 0.64 to 12.4 µM after 24 h incubation. Overall, LNPs are promising candidates for drug delivery applications, and the superparamagnetic behavior of Fe3O4-LNPs makes them promising for cancer therapy and diagnosis, such as magnetic targeting and magnetic resonance imaging.


Assuntos
Implantes Absorvíveis , Antineoplásicos/administração & dosagem , Preparações de Ação Retardada/administração & dosagem , Lignina/química , Nanocápsulas/química , Neoplasias Experimentais/tratamento farmacológico , Neoplasias Experimentais/patologia , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Preparações de Ação Retardada/química , Humanos , Lignina/administração & dosagem , Células MCF-7 , Nanocápsulas/administração & dosagem , Nanocápsulas/ultraestrutura , Resultado do Tratamento
13.
Cardiovasc Ultrasound ; 15(1): 1, 2017 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-28069008

RESUMO

BACKGROUND: We evaluated echocardiographic area-length methods to measure left ventricle (LV) volumes and ejection fraction (EF) in parasternal short axis views in comparison with cardiac computed tomography (CT) in pigs with chronic myocardial infarction (MI). METHODS: Male farm pigs with surgical occlusion of the left anterior descending coronary artery (n = 9) or sham operation (n = 5) had transthoracic echocardiography and cardiac-CT 3 months after surgery. We measured length of the LV in parasternal long axis view, and both systolic and diastolic LV areas in parasternal short axis views at the level of mitral valve, papillary muscles and apex. Volumes and EF of the LV were calculated using Simpson's method of discs (tri-plane area) or Cylinder-hemiellipsoid method (single plane area). RESULTS: The pigs with coronary occlusion had anterior MI scars and reduced EF (average EF 42 ± 10%) by CT. Measurements of LV volumes and EF were reproducible by echocardiography. Compared with CT, end-diastolic volume (EDV) measured by echocardiography showed good correlation and agreement using either Simpson's method (r = 0.90; mean difference -2, 95% CI -47 to 43 mL) or Cylinder-hemiellipsoid method (r = 0.94; mean difference 3, 95% CI -44 to 49 mL). Furthermore, End-systolic volume (ESV) measured by echocardiography showed also good correlation and agreement using either Simpson's method (r = 0.94; mean difference 12 ml, 95% CI: -16 to 40) or Cylinder-hemiellipsoid method (r = 0.97; mean difference:13 ml, 95% CI: -8 to 33). EF was underestimated using either Simpson's method (r = 0.78; mean difference -6, 95% CI -11 to 1%) or Cylinder-hemiellipsoid method (r = 0.74; mean difference -4, 95% CI-10 to 2%). CONCLUSION: Our results indicate that measurement of LV volumes may be accurate, but EF is underestimated using either three or single parasternal short axis planes by echocardiography in a large animal model of chronic MI.


Assuntos
Ecocardiografia/métodos , Ventrículos do Coração/diagnóstico por imagem , Infarto do Miocárdio/diagnóstico , Tomografia Computadorizada por Raios X/métodos , Animais , Doença Crônica , Modelos Animais de Doenças , Masculino , Reprodutibilidade dos Testes , Suínos
14.
Sci Rep ; 6: 29324, 2016 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-27381834

RESUMO

A straightforward solution-based method to modify the biofunctionality of stainless steel (SS) using heterobifunctional silane-polyethylene glycol (silane-PEG) overlayers is reported. Reduced nonspecific biofouling of both proteins and bacteria onto SS and further selective biofunctionalization of the modified surface were achieved. According to photoelectron spectroscopy analyses, the silane-PEGs formed less than 10 Å thick overlayers with close to 90% surface coverage and reproducible chemical compositions. Consequently, the surfaces also became more hydrophilic, and the observed non-specific biofouling of proteins was reduced by approximately 70%. In addition, the attachment of E. coli was reduced by more than 65%. Moreover, the potential of the overlayer to be further modified was demonstrated by successfully coupling biotinylated alkaline phosphatase (bAP) to a silane-PEG-biotin overlayer via avidin-biotin bridges. The activity of the immobilized enzyme was shown to be well preserved without compromising the achieved antifouling properties. Overall, the simple solution-based approach enables the tailoring of SS to enhance its activity for biomedical and biotechnological applications.


Assuntos
Avidina/metabolismo , Incrustação Biológica/prevenção & controle , Biotina/metabolismo , Polietilenoglicóis/metabolismo , Silanos/metabolismo , Aço Inoxidável/química , Propriedades de Superfície , Aderência Bacteriana , Interações Hidrofóbicas e Hidrofílicas , Ligação Proteica
15.
Front Pharmacol ; 7: 115, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27199757

RESUMO

The use of cardiopulmonary bypass (CPB) and aortic cross-clamping causes myocardial ischemia-reperfusion injury (I-RI) and can lead to reduced postoperative cardiac function. We investigated whether this injury could be attenuated by thymosin beta 4 (TB4), a peptide which has showed cardioprotective effects. Pigs received either TB4 or vehicle and underwent CPB and aortic cross-clamping for 60 min with cold intermittent blood-cardioplegia and were then followed for 30 h. Myocardial function and blood flow was studied by cardiac magnetic resonance and PET imaging. Tissue and plasma samples were analyzed to determine the amount of cardiomyocyte necrosis and apoptosis as well as pharmacokinetics of the peptide. In vitro studies were performed to assess its influence on blood coagulation and vasomotor tone. Serum levels of the peptide were increased after administration compared to control samples. TB4 did not decrease the amount of cell death. Cardiac function and global myocardial blood flow was similar between the study groups. At high doses a vasoconstrictor effect on mesentery arteries and a vasodilator effect on coronary arteries was observed and blood clot firmness was reduced when tested in the presence of an antiplatelet agent. Despite promising results in previous trials the cardioprotective effect of TB4 was not demonstrated in this model for global myocardial I-RI.

16.
J Nucl Cardiol ; 22(4): 655-65, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25698475

RESUMO

AIMS: Large animal models are needed to study disease mechanisms in heart failure (HF). In the present study we characterized the functional, metabolic, and structural changes of myocardium in a novel pig model of chronic myocardial infarction (MI) by using multimodality imaging and histology. METHODS AND RESULTS: Male farm pigs underwent a two-step occlusion of the left anterior descending coronary artery with concurrent distal ligation and implantation of a proximal ameroid constrictor (HF group), or sham operation (control group). Three months after the operation, cardiac output and wall stress were measured by echocardiography. Left ventricle (LV) volumes and mass were measured by computed tomography (CT). Myocardial perfusion was evaluated by [(15)O]water and oxygen consumption using [(11)C]acetate positron emission tomography, and the efficiency of myocardial work was calculated. Histological examinations were conducted to detect MI, hypertrophy, and fibrosis. Animals in the HF group had a large anterior MI scar. CT showed larger LV diastolic volume and lower ejection fraction in HF pigs than in controls. Perfusion and oxygen consumption in the remote non-infarcted myocardium were preserved in HF pigs as compared to controls. Global LV work and efficiency were significantly lower in HF than control pigs and was associated with increased wall stress. Histology showed myocyte hypertrophy but not increased interstitial fibrosis in the remote segments in HF pigs. CONCLUSIONS: The chronic post-infarction model of HF is suitable for studies aimed to evaluate LV remodeling and changes in oxidative metabolism and can be useful for testing new therapies for HF.


Assuntos
Modelos Animais de Doenças , Insuficiência Cardíaca/fisiopatologia , Consumo de Oxigênio , Disfunção Ventricular Esquerda/diagnóstico , Disfunção Ventricular Esquerda/fisiopatologia , Remodelação Ventricular , Animais , Doença Crônica , Ecocardiografia/métodos , Insuficiência Cardíaca/complicações , Insuficiência Cardíaca/diagnóstico , Ventrículos do Coração/patologia , Ventrículos do Coração/fisiopatologia , Masculino , Imagem de Perfusão do Miocárdio/métodos , Tomografia por Emissão de Pósitrons/métodos , Suínos , Tomografia Computadorizada por Raios X/métodos , Disfunção Ventricular Esquerda/etiologia
17.
Eur J Clin Pharmacol ; 65(1): 89-95, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18777173

RESUMO

PURPOSE: The effect of topical miconazole oral gel and systemic oral voriconazole on the pharmacokinetics of oral etoricoxib was studied in 12 healthy volunteers. METHODS: Plasma concentrations of etoricoxib, miconazole, voriconazole, and thromboxane B(2) generation were followed after ingestion of 60 mg etoricoxib without pretreatment, after topical administration of miconazole oral gel (85 mg x 3, 3 days), or after oral voriconazole (400 mg x 2, 1st day, 200 mg x 2, 2nd day). RESULTS: Etoricoxib area under the plasma concentration-time curve (AUC(0-00)) and maximum plasma concentration (C(max)) geometric mean ratios (GMR) with/without miconazole were 1.69 {90% confidence interval (CI); 1.46-1.92} and 1.12 (90% CI; 0.99-1.25), respectively, and corresponding GMRs with/without voriconazole were 1.49 (90% CI; 1.37-1.61) and 1.19 (90% CI; 1.08-1.31), respectively. CONCLUSIONS: Miconazole oral gel and oral voriconazole produced comparable increase in the exposure to etoricoxib, presumably via CYP3A inhibition.


Assuntos
Antifúngicos/administração & dosagem , Inibidores de Ciclo-Oxigenase/farmacocinética , Inibidores Enzimáticos/administração & dosagem , Miconazol/administração & dosagem , Piridinas/farmacocinética , Pirimidinas/administração & dosagem , Sulfonas/farmacocinética , Triazóis/administração & dosagem , Administração Oral , Administração Tópica , Adulto , Antifúngicos/sangue , Antifúngicos/farmacocinética , Biotransformação/efeitos dos fármacos , Estudos Cross-Over , Inibidores de Ciclo-Oxigenase/administração & dosagem , Inibidores de Ciclo-Oxigenase/sangue , Citocromo P-450 CYP3A , Inibidores das Enzimas do Citocromo P-450 , Sistema Enzimático do Citocromo P-450/metabolismo , Interações Medicamentosas , Inibidores Enzimáticos/sangue , Inibidores Enzimáticos/farmacocinética , Etoricoxib , Géis , Humanos , Masculino , Miconazol/sangue , Miconazol/farmacocinética , Piridinas/administração & dosagem , Piridinas/sangue , Pirimidinas/sangue , Pirimidinas/farmacocinética , Sulfonas/administração & dosagem , Sulfonas/sangue , Tromboxano B2/sangue , Triazóis/sangue , Triazóis/farmacocinética , Voriconazol , Adulto Jovem
18.
Fundam Clin Pharmacol ; 21(6): 651-6, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18034666

RESUMO

The nonsteroidal anti-inflammatory drug diclofenac is extensively metabolized by cytochrome P450 (CYP) enzymes, mainly by CYP2C9. Our objective was to study the effect of voriconazole, a potent inhibitor of several CYP enzymes, on the pharmacokinetics of diclofenac. This study had a two-way, open, crossover design and included 10 healthy Caucasian male subjects. In the control phase, the subjects ingested a single 50-mg oral dose of diclofenac. In the voriconazole phase, the subjects ingested voriconazole 400 mg twice daily on the first day and 200 mg twice daily on the second day, and 50 mg diclofenac was given 1 h after the last dose of voriconazole. Plasma diclofenac concentrations were determined for up to 24 h post-dose. In the voriconazole phase, the area under the plasma concentration-time curve of diclofenac was 178% (95% CI 143-212%; P < 0.001) and the peak plasma concentration was 214% (95% CI 128-300%; P < 0.05) of the respective control value. Voriconazole did not affect significantly the elimination half-life or time to maximum concentration of diclofenac. The renal clearance of diclofenac was decreased by 47% (95% CI -76% to -16%; P < 0.01) by voriconazole. In conclusion, voriconazole increased exposure to diclofenac, probably mainly by inhibition of its cytochrome P450 (CYP)-mediated metabolism. The inhibition of CYP2C9, and to some extent that of CYP3A4 and CYP2C19 enzymes during the first-pass metabolism of diclofenac seems to be involved in the interaction. The clinical importance of the interaction between voriconazole and diclofenac remains to be studied, but lower doses of diclofenac may be adequate for patients receiving voriconazole.


Assuntos
Anti-Inflamatórios não Esteroides/farmacocinética , Antifúngicos/farmacologia , Diclofenaco/farmacocinética , Pirimidinas/farmacologia , Triazóis/farmacologia , Adulto , Área Sob a Curva , Hidrocarboneto de Aril Hidroxilases/genética , Estudos Cross-Over , Citocromo P-450 CYP2C9 , Interações Medicamentosas , Meia-Vida , Humanos , Masculino , Voriconazol
19.
Antimicrob Agents Chemother ; 50(6): 1967-72, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16723553

RESUMO

Our objective was to study the effects of the antifungals voriconazole and fluconazole on the pharmacokinetics of S-(+)- and R-(-)-ibuprofen. Twelve healthy male volunteers took a single oral dose of 400 mg racemic ibuprofen in a randomized order either alone, after ingestion of voriconazole at 400 mg twice daily on the first day and 200 mg twice daily on the second day, or after ingestion of fluconazole at 400 mg on the first day and 200 mg on the second day. Ibuprofen was ingested 1 h after administration of the last dose of voriconazole or fluconazole. Plasma concentrations of S-(+)- and R-(-)-ibuprofen were measured for up to 24 h. In the voriconazole phase, the mean area under the plasma concentration-time curve (AUC) of S-(+)-ibuprofen was 205% (P < 0.001) of the respective control value and the mean peak plasma concentration (C(max)) was 122% (P < 0.01) of the respective control value. The mean elimination half-life (t(1/2)) was prolonged from 2.4 to 3.2 h (P < 0.01) by voriconazole. In the fluconazole phase, the mean AUC of S-(+)-ibuprofen was 183% of the control value (P < 0.001) and its mean C(max) was 116% of the control value (P < 0.05). The mean t(1/2) of S-(+)-ibuprofen was prolonged from 2.4 to 3.1 h (P < 0.05) by fluconazole. The geometric mean S-(+)-ibuprofen AUC ratios in the voriconazole and fluconazole phases were 2.01 (90% confidence interval [CI], 1.80 to 2.22) and 1.82 (90% CI, 1.72 to 1.91), respectively, i.e., above the bioequivalence acceptance upper limit of 1.25. Voriconazole and fluconazole had only weak effects on the pharmacokinetics of R-(-)-ibuprofen. In conclusion, voriconazole and fluconazole increased the levels of exposure to S-(+)-ibuprofen 2- and 1.8-fold, respectively. This was likely caused by inhibition of the cytochrome P450 2C9-mediated metabolism of S-(+)-ibuprofen. A reduction of the ibuprofen dosage should be considered when ibuprofen is coadministered with voriconazole or fluconazole, especially when the initial ibuprofen dose is high.


Assuntos
Analgésicos não Narcóticos/farmacocinética , Antifúngicos/farmacologia , Fluconazol/farmacologia , Ibuprofeno/farmacocinética , Pirimidinas/farmacologia , Triazóis/farmacologia , Adulto , Analgésicos não Narcóticos/efeitos adversos , Analgésicos não Narcóticos/sangue , Antifúngicos/farmacocinética , Área Sob a Curva , Estudos Cross-Over , Relação Dose-Resposta a Droga , Esquema de Medicação , Interações Medicamentosas , Fluconazol/farmacocinética , Meia-Vida , Humanos , Ibuprofeno/efeitos adversos , Ibuprofeno/sangue , Masculino , Pirimidinas/farmacocinética , Equivalência Terapêutica , Triazóis/farmacocinética , Voriconazol
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...