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1.
Acta Anaesthesiol Scand ; 61(9): 1133-1141, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28741744

RESUMO

BACKGROUND: Unintentional perioperative hypothermia causes serious adverse effects to surgical patients. Thermal suit (T-Balance® ) is an option for passive warming perioperatively. We hypothesized that the thermal suit will not maintain normothermia more efficiently than conventional cotton clothes when also other preventive procedures against unintentional hypothermia are used. METHODS: One hundred patients were recruited to this prospective, randomized trial. They were allocated to the Thermal Suit group or a Control group wearing conventional hospital cotton clothes. All patients received our institution's standard treatment against unintentional hypothermia including a warming mattress, a forced-air upper body warming blanket and a warming device for intravenous fluids. Eardrum temperature was measured pre-operatively. In the operating room and post-anaesthesia care unit temperatures were measured from four locations: oesophagus, left axilla, dorsal surface of the left middle finger and dorsum of the left foot. The primary outcome measure was temperature change during robotic-assisted laparoscopic radical prostatectomy. RESULTS: The temperatures of 96 patients were analysed. There was no difference in mean core temperatures, axillary temperatures or skin temperatures on the finger between the groups. Only foot dorsum temperatures were significantly lower in the Thermal Suit group. Intraoperative temperature changes were similar in both groups. In the post-anaesthesia care unit temperature changes were minimal and they did not differ between the groups. CONCLUSION: Provided that standard preventive procedures in maintaining normothermia are effective the thermal suit does not provide any additional benefit over conventional cotton clothes during robotic-assisted laparoscopic radical prostatectomy.


Assuntos
Anestesia Geral/métodos , Vestuário , Hipotermia/prevenção & controle , Complicações Intraoperatórias/prevenção & controle , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Roupas de Cama, Mesa e Banho , Temperatura Corporal , Humanos , Laparoscopia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Prostatectomia , Robótica , Temperatura Cutânea , Resultado do Tratamento , Adulto Jovem
2.
Anaesth Intensive Care ; 44(6): 729-733, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27832560

RESUMO

Dabigatran is a direct thrombin inhibitor, which is increasingly likely to be encountered in patients presenting for surgery. This study examines whether there is a consistent effect of dabigatran on the thromboelastogram (TEG) and whether this correlates with the effects of dabigatran on traditional coagulation parameters. Twenty patients taking dabigatran had blood sampled for kaolin-activated whole blood TEG analysis and routine coagulation testing. There was a statistically significant correlation between thrombin clotting time (TCT) and R-time (R=0.77, P=0.0001) and between activated partial thromboplastin time (APTT) and R-time (R=0.68, P=0.0013), but not between TCT and alpha-angle (R= -0.4232, P=0.071). Despite the moderate to high correlation between the TEG R-time and the TCT and APTT, there appeared to be no consistent effect of dabigatran on the TEG. These findings suggest that use of kaolin-activated whole blood TEG does not add additional benefit to traditional coagulation tests when monitoring the effect of dabigatran.


Assuntos
Antitrombinas/farmacologia , Dabigatrana/farmacologia , Caulim/farmacologia , Tromboelastografia , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tempo de Trombina
3.
Br J Anaesth ; 115(2): 258-66, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26137969

RESUMO

BACKGROUND: Concomitantly recorded Bispectral Index® (BIS) and Entropy™ values sometimes show discordant trends during general anaesthesia. Previously, no attempt had been made to discover which EEG characteristics cause discrepancies between BIS and Entropy. We compared BIS and Entropy values, and analysed the changes in the raw EEG signal during surgical anaesthesia with sevoflurane. METHODS: In this prospective, open-label study, 65 patients receiving general anaesthesia with sevoflurane were enrolled. BIS, Entropy and multichannel digital EEG were recorded. Concurrent BIS and State Entropy (SE) values were selected. Whenever BIS and SE values showed ≥10-unit disagreement for ≥60 s, the raw EEG signal was analysed both in time and frequency domain. RESULTS: A ≥10-unit disagreement ≥60 s was detected 428 times in 51 patients. These 428 episodes accounted for 5158 (11%) out of 45 918 analysed index pairs. During EEG burst suppression, SE was higher than BIS in 35 out of 49 episodes. During delta-theta dominance, BIS was higher than SE in 141 out of 157 episodes. During alpha or beta activity, SE was higher than BIS in all 49 episodes. During electrocautery, both BIS and SE changed, sometimes in the opposite direction, but returned to baseline values after electrocautery. Electromyography caused index disagreement four times (BIS > SE). CONCLUSIONS: Certain specific EEG patterns, and artifacts, are associated with discrepancies between BIS and SE. Time and frequency domain analyses of the original EEG improve the interpretation of studies involving BIS, Entropy and other EEG-based indices. CLINICAL TRIAL REGISTRATIONCLINICALTRIALSGOVIDENTIFIER: NCT01077674.


Assuntos
Anestésicos Inalatórios/farmacologia , Monitores de Consciência , Eletroencefalografia , Entropia , Éteres Metílicos/farmacologia , Idoso , Anestesia , Eletromiografia , Feminino , Humanos , Pessoa de Meia-Idade , Monitorização Intraoperatória , Estudos Prospectivos , Sevoflurano
4.
Biomed Mater Eng ; 24(3): 1595-607, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24840198

RESUMO

BACKGROUND: Wood has been used as a model material for the development of novel fiber-reinforced composite bone substitute biomaterials. In previous studies heat treatment of wood was perceived to significantly increase the osteoconductivity of implanted wood material. AIM: The objective of this study was to examine some of the changing attributes of wood materials that may contribute to improved biological responses gained with heat treatment. METHODS: Untreated and 140°C and 200°C heat-treated downy birch (Betula pubescens Ehrh.) were used as the wood materials. Surface roughness and the effect of pre-measurement grinding were measured with contact and non-contact profilometry. Liquid interaction was assessed with a dipping test using two manufactured liquids (simulated blood) as well as human blood. SEM was used to visualize possible heat treatment-induced changes in the hierarchical structure of wood. RESULTS: The surface roughness was observed to significantly decrease with heat treatment. Grinding methods had more influence on the surface contour and roughness than heat treatment. The penetration of the human blood in the 200°C heat-treated exceeded that in the untreated and 140°C heat-treated materials. SEM showed no significant change due to heat treatment in the dry-state morphology of the wood. DISCUSSION: The results of the liquid penetration test support previous findings in literature concerning the effects of heat treatment on the biological response to implanted wood. Heat-treatment has only a marginal effect on the surface contour of wood. The highly specialized liquid conveyance system of wood may serve as a biomimetic model for the further development of tailored fiber-composite materials.


Assuntos
Sangue/metabolismo , Temperatura Alta , Madeira/química , Madeira/metabolismo , Absorção Fisico-Química , Betula , Materiais Biomiméticos/química , Materiais Biomiméticos/metabolismo , Substitutos Ósseos/química , Substitutos Ósseos/metabolismo , Humanos , Teste de Materiais , Propriedades de Superfície , Molhabilidade
5.
J Mater Sci Mater Med ; 24(5): 1145-52, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23440429

RESUMO

The purpose of this study was to investigate the effect of fiber orientation of a fiber-reinforced composite (FRC) made of poly-methyl-methacrylate (PMMA) and E-glass to the surface fabrication process by solvent dissolution. Intention of the dissolution process was to expose the fibers and create a macroporous surface onto the FRC to enhance bone bonding of the material. The effect of dissolution and fiber direction to the bone bonding capability of the FRC material was also tested. Three groups of FRC specimens (n = 18/group) were made of PMMA and E-glass fiber reinforcement: (a) group with continuous fibers parallel to the surface of the specimen, (b) continuous fibers oriented perpendicularly to the surface, (c) randomly oriented short (discontinuous) fibers. Fourth specimen group (n = 18) made of plain PMMA served as controls. The specimens were subjected to a solvent treatment by tetrahydrofuran (THF) of either 5, 15 or 30 min of time (n = 6/time point), and the advancement of the dissolution (front) was measured. The solvent treatment also exposed the fibers and created a surface roughness on to the specimens. The solvent treated specimens were embedded into plaster of Paris to simulate bone bonding by mechanical locking and a pull-out test was undertaken to determine the strength of the attachment. All the FRC specimens dissolved as function of time, as the control group showed no marked dissolution during the study period. The specimens with fibers along the direction of long axis of specimen began to dissolve significantly faster than specimens in other groups, but the test specimens with randomly oriented short fibers showed the greatest depth of dissolution after 30 min. The pull-out test showed that the PMMA specimens with fibers were retained better by the plaster of Paris than specimens without fibers. However, direction of the fibers considerably influenced the force of attachment. The fiber reinforcement increases significantly the dissolution speed, and the orientation of the glass fibers has great effect on the dissolving depth of the polymer matrix of the composite, and thus on the exposure of fibers. The glass fibers exposed by the solvent treatment enhanced effectively the attachment of the specimen to the bone modeling material.


Assuntos
Substitutos Ósseos/química , Materiais Revestidos Biocompatíveis/síntese química , Resinas Compostas/síntese química , Vidro/química , Polimetil Metacrilato/química , Substitutos Ósseos/síntese química , Materiais Revestidos Biocompatíveis/química , Resinas Compostas/química , Teste de Materiais/instrumentação , Teste de Materiais/métodos , Microscopia Eletrônica de Varredura , Polímeros/síntese química , Polímeros/química , Polimetil Metacrilato/síntese química , Estresse Mecânico , Propriedades de Superfície , Resistência à Tração/fisiologia
6.
Acta Anaesthesiol Scand ; 57(3): 364-72, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22928590

RESUMO

BACKGROUND: Electroencephalogram (EEG)-based depth of anaesthesia monitoring is susceptible to contaminating electromyographic (EMG) activity. Many authorities have suggested that anaesthesiologists using these monitors should interpret the raw EEG waveform seen on the anaesthesia monitor. METHODS: In 34 patients anaesthetized with propofol using two doses of rocuronium (0.6 and 1.2 mg/kg), we studied whether the EMG arousal can be detected visually on the anaesthesia monitor. The Bispectral Index (BIS) and Entropy biosignals on the monitor were recorded with a video camera, and the one-channel EEG recorded by the Entropy strip was collected on a laptop computer. The recordings and the one-channel EEG were analyzed offline by two experts (anaesthesiologist and neurophysiologist), both with a long experience on anaesthesia-related EEG. RESULTS: EMG arousal existed in 14/34 and 13/33 patients in the BIS and Entropy biosignals, respectively. The anaesthesiologist detected EMG on the monitor in 7/14 patients with BIS (sensitivity 50%) and in 4/13 patients with Entropy (31%). The clinical neurophysiologist detected EMG in 6/14 (43%) patients with BIS and in 5/13 (38%) with Entropy. The specificity of the EMG analyses was 55 and 65% with BIS, and 85 and 90% with Entropy. EMG arousal was detected in BIS biosignal in 10/17 and 4/17 patients with 0.6 and 1.2 mg/kg doses of rocuronium (P = 0.04). CONCLUSIONS: In contrast to many EEG phenomena, EMG activity cannot be accurately detected visually from the raw EEG on the anaesthesia monitor. Further development in the quality of the anaesthesia monitors is warranted.


Assuntos
Anestesia , Nível de Alerta/fisiologia , Monitores de Consciência , Eletromiografia/instrumentação , Monitorização Intraoperatória/instrumentação , Adulto , Método Duplo-Cego , Eletroencefalografia , Determinação de Ponto Final , Entropia , Feminino , Procedimentos Cirúrgicos em Ginecologia , Humanos , Pessoa de Meia-Idade , Estudos Prospectivos , Reprodutibilidade dos Testes
7.
Bioresour Technol ; 128: 22-9, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23196217

RESUMO

Pyrolysis of pine and gasification of pine chars was studied in this work, focusing on the influence of organically bound metals. Selective leaching of the major ash-forming elements in pine wood was performed with different acids, namely, nitric, sulfuric, hydrochloric and oxalic acids. No other major changes in the chemical composition of the biomass were observed except the removal of the metals. The effect of organically bound sodium, potassium, magnesium and calcium was studied in both pyrolysis and gasification. Removal of the metals had a positive effect on the pyrolysis, resulting in higher bio-oil, lower char and gas yields.


Assuntos
Gases/síntese química , Incineração/métodos , Metais/química , Compostos Orgânicos/química , Pinus/química
8.
Acta Anaesthesiol Scand ; 56(4): 465-73, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22289106

RESUMO

BACKGROUND: Sugammadex is designed to antagonize neuromuscular blockade (NMB) induced by rocuronium or vecuronium. In clinical practice, we have noticed a rise in the numerical values of bispectral index (BIS) and Entropy, two electroencephalogram (EEG) - based depth of anesthesia monitors, during the reversal of the NMB with sugammadex. The aim of this prospective, randomized, double-blind study was to test this impression and to compare the effects of sugammadex and neostigmine on the BIS and Entropy values during the reversal of the NMB. METHODS: Thirty patients undergoing gynecological operations were studied. Patients were anesthetized with target-controlled infusions of propofol and remifentanil, and rocuronium was used to induce NMB. After operation, during light propofol-remifentanil anesthesia, NMB was antagonized with sugammadex or neostigmine. During the following 5 min, the numerical values of BIS, BIS electromyographic (BIS EMG) and Entropy were recorded on a laptop computer, as well as the biosignal recorded by the Entropy strip. The Entropy biosignal was studied off-line both in time and frequency domain to see if NMB reversal causes changes in EEG. RESULTS: In some patients, administration of sugammadex or neostigmine caused a significant rise in the numerical values of BIS, BIS EMG and Entropy. This phenomenon was most likely caused by increased electromyographic (EMG) activity. The administration of sugammadex or neostigmine appeared to have only minimal effect on EEG. CONCLUSION: The EMG contamination of EEG causes BIS and Entropy values to rise during reversal of rocuronium-induced NMB in light propofol-remifentanil anesthesia.


Assuntos
Eletroencefalografia/efeitos dos fármacos , Eletromiografia , Entropia , Neostigmina/farmacologia , Bloqueio Neuromuscular , gama-Ciclodextrinas/farmacologia , Adulto , Barreira Hematoencefálica , Método Duplo-Cego , Humanos , Pessoa de Meia-Idade , Estudos Prospectivos , Sugammadex
9.
J Long Term Eff Med Implants ; 21(2): 139-48, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22043972

RESUMO

The clinical and radiological outcomes of bioactive glass (BAG)-S53P4 and autograft bone (AB) used as bone-graft substitutes in depressed tibial plateau fractures were evaluated in a prospective randomized 11-year follow-up study. All patients (n = 29) had sustained tibial plateau fractures with a joint-line depression of >3 mm. Fifteen patients (5 patients the BAG group, 10 patients in the AB group) participated in this long-term follow-up. X-rays were taken preoperatively, postoperatively, and at the long-term follow-up, and computed tomography (CT) scans were made at the long-term follow-up for evaluation of the bone substitute, osteoarthritis, the tibial-femoral angle, and deviation of mechanical axes. No material-dependent adverse effects were seen in any patient. The means of the articular surface depression on X-rays at the long-term follow-up were 1.4 mm (range: 0-2 mm) in the BAG group and 1.4 mm (range: 0-4 mm) in the AB group, and on CT scans the means were 2.2 mm (range: 2-3 mm), and 2.1 mm (range: 0-3), respectively. No significant difference in the tibial-femoral angle or deviation of mechanical axes was observed between the two groups. BAG-S53P4 can be used as a bone substitute in depressed lateral tibial plateau fractures with good functional and radiological long-term results.


Assuntos
Substitutos Ósseos/uso terapêutico , Consolidação da Fratura , Ílio/transplante , Fraturas da Tíbia/cirurgia , Adulto , Idoso , Feminino , Seguimentos , Vidro , Humanos , Articulação do Joelho/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Medição da Dor , Estudos Prospectivos , Tomografia Computadorizada por Raios X , Transplante Autólogo
11.
Br J Anaesth ; 106(1): 69-76, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21051491

RESUMO

BACKGROUND: Entropy™, an anaesthetic EEG monitoring method, yields two parameters: State Entropy (SE) and Response Entropy (RE). SE reflects the hypnotic level of the patient. RE covers also the EMG-dominant part of the frequency spectrum, reflecting the upper facial EMG response to noxious stimulation. We studied the EEG, EMG, and Entropy values before and after skin incision, and the effect of rocuronium on Entropy and EMG at skin incision during sevoflurane-nitrous oxide (N2O) anaesthesia. METHODS: Thirty-eight patients were anaesthetized with sevoflurane-N2O or sevoflurane-N2O-rocuronium. The biosignal was stored and analysed off-line to detect EEG patterns, EMG, and artifacts. The signal, its power spectrum, SE, RE, and RE-SE values were analysed before and after skin incision. The EEG arousal was classified as ß (increase in over 8 Hz activity and decrease in under 4 Hz activity with a typical ß pattern) or δ (increase in under 4 Hz activity with the characteristic rhythmic δ pattern and a decrease in over 8 Hz activity). RESULTS: The EEG arousal appeared in 17 of 19 and 15 of 19 patients (NS), and the EMG arousal in 0 of 19 and 13 of 19 patients (P<0.01) with and without rocuronium, respectively. Both ß (n=30) and EMG arousals increased SE and RE. The δ arousal (n=2) decreased both SE and RE. A significant increase in RE-SE values was only seen in patients without rocuronium. CONCLUSIONS: During sevoflurane-N2O anaesthesia, both EEG and EMG arousals were seen. ß and δ arousals had opposite effects on the Entropy values. The EMG arousal was abolished by rocuronium at the train of four level 0/4.


Assuntos
Monitorização Intraoperatória/métodos , Fármacos Neuromusculares não Despolarizantes/farmacologia , Adolescente , Adulto , Androstanóis/farmacologia , Anestesia por Inalação , Procedimentos Cirúrgicos Dermatológicos , Eletroencefalografia/efeitos dos fármacos , Eletroencefalografia/métodos , Eletromiografia/efeitos dos fármacos , Eletromiografia/métodos , Entropia , Humanos , Pessoa de Meia-Idade , Rocurônio , Processamento de Sinais Assistido por Computador , Adulto Jovem
12.
J Mater Sci Mater Med ; 21(8): 2345-54, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20464458

RESUMO

Wood is a natural fiber reinforced composite. It structurally resembles bone tissue to some extent. Specially heat-treated birch wood has been used as a model material for further development of synthetic fiber reinforced composites (FRC) for medical and dental use. In previous studies it has been shown, that heat treatment has a positive effect on the osteoconductivity of an implanted wood. In this study the effects of two different heat treatment temperatures (140 and 200 degrees C) on wood were studied in vitro. Untreated wood was used as a control material. Heat treatment induced biomechanical changes were studied with flexural and compressive tests on dry birch wood as well as on wood after 63 days of simulated body fluid (SBF) immersion. Dimensional changes, SBF sorption and hydroxylapatite type mineral formation were also assessed. The results showed that SBF immersion decreases the biomechanical performance of wood and that the heat treatment diminishes the effect of SBF immersion on biomechanical properties. With scanning electron microscopy and energy dispersive X-ray analysis it was shown that hydroxylapatite type mineral precipitation formed on the 200 degrees C heat-treated wood. An increased weight gain of the same material during SBF immersion supported this finding. The results of this study give more detailed insight of the biologically relevant changes that heat treatment induces in wood material. Furthermore the findings in this study are in line with previous in vivo studies.


Assuntos
Fenômenos Biomecânicos/fisiologia , Precipitação Química , Temperatura Alta , Minerais/química , Madeira/química , Adsorção/fisiologia , Líquidos Corporais/metabolismo , Líquidos Corporais/fisiologia , Força Compressiva , Durapatita , Imersão , Técnicas In Vitro , Teste de Materiais , Microscopia Eletrônica de Varredura , Minerais/metabolismo , Propriedades de Superfície , Resistência à Tração , Madeira/metabolismo
13.
J Mater Sci Mater Med ; 21(5): 1685-92, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20162330

RESUMO

Polymethylmethacrylate (PMMA) has been used in many orthopedic and dental applications since the 1960s. Biocompatibility of newly developed surface porous fiber reinforced (SPFR) PMMA based composite has not been previously proven in cell culture environment. Analysis of rat bone marrow stromal cells grown on the different test materials showed only little difference in normalized cell activity or bone sialoprotein (BSP) production between the test materials, but the osteocalcin (OC) levels remained higher (P < 0.015-0.005) through out the test with SPFR-material when compared to tissue culture poly styrene (TCPS). The cells grown on SP-FRC material also showed highest calcium depletion from the culture medium (P < 0.026-0.001) when compared to all other test substrates. SEM images of the cultured samples confirmed that all the materials enabled cell spreading and growth on their surface, but the roughened surface remarkably enhanced this process of cell attachment, division and calcified nodule formation. This study shows that the SP-FRC composite material does not elicit harmful/toxic reactions in cell cultures more than neutral TCPS and can be considered biocompatible. The material possesses good capabilities to form new mineralized tissue onto its surface, and through that a possibility to bond directly to bone. Rough surface seems to enhance osteoblast proliferation and formation of mineralized extracellular matrix.


Assuntos
Osteoblastos/citologia , Osteoblastos/metabolismo , Polimetil Metacrilato/química , Animais , Osso e Ossos/metabolismo , Proliferação de Células , Células Cultivadas , Matriz Extracelular/metabolismo , Vidro/química , Sialoproteína de Ligação à Integrina , Masculino , Osteocalcina/metabolismo , Polimetil Metacrilato/metabolismo , Ratos , Ratos Sprague-Dawley , Sialoglicoproteínas
14.
Acta Biomater ; 5(5): 1639-46, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19268643

RESUMO

A method has recently been developed for producing fibre-reinforced composites (FRC) with porous surfaces, intended for use as load-bearing orthopaedic implants. This study focuses on evaluation of the bone-bonding behaviour of FRC implants. Three types of cylindrical implants, i.e. FRC implants with a porous surface, solid polymethyl methacrylate (PMMA) implants and titanium (Ti) implants, were inserted in a transverse direction into the intercondular trabeculous bone area of distal femurs and proximal tibias of New Zealand White rabbits. Animals were sacrificed at 3, 6 and 12 weeks post operation, and push-out tests (n=5-6 per implant type per time point) were then carried out. At 12 weeks the shear force at the porous FRC-bone interface was significantly higher (283.3+/-55.3N) than the shear force at interfaces of solid PMMA/bone (14.4+/-11.0 N; p<0.001) and Ti/bone (130.6+/-22.2N; p=0.001). Histological observation revealed new bone growth into the porous surface structure of FRC implants. Solid PMMA and Ti implants were encapsulated mostly with fibrous connective tissue. Finite element analysis (FEA) revealed that porous FRC implants had mechanical properties which could be tailored to smooth the shear stress distribution at the bone-implant interface and reduce the stress-shielding effect.


Assuntos
Osso e Ossos/fisiologia , Vidro/química , Implantes Experimentais , Animais , Osso e Ossos/citologia , Análise de Elementos Finitos , Microscopia Eletrônica de Varredura , Polimetil Metacrilato/metabolismo , Porosidade , Coelhos , Estresse Mecânico , Propriedades de Superfície
15.
Acta Biomater ; 5(5): 1596-604, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19231305

RESUMO

Wood is a natural porous fibre composite, which has some structural similarities to bone. Recently, it has been used as a modelling material in developing synthetic fibre-reinforced composite to be used as load-bearing non-metallic artificial bone material. In this study, the behaviour of wood implanted into bone was studied in vivo in the femur bone of the rabbit. Wood was pre-treated by heat, which altered its chemical composition and structure, as well as the biomechanical properties. In the heat treatment, wood's dimensional stability is enhanced, equilibrium moisture content reduces and the biological durability increases. Cone-shaped implants were manufactured from heat-treated (at 200 and 140 degrees C) birch wood (Betula pubescens) and from untreated birch. A total of 62 implants were placed in the distal femur of 50 white New Zealand rabbits. The behaviour of the implants was studied at 4, 8 and 20 weeks with histological and histometrical analysis. Osteoconductive contact line and the presence of fibrous tissue and foreign body reaction were determined. The amount of fibrous tissue diminished with time, and the absence of foreign body reaction was found to be in correlation to the amount of heat treatment. Histologically found contact between the implant and the host bone at the interface was significantly more abundant in the 200 degrees C group (avg. 12.8%) vs. the 140 degrees C (avg. 2.7%) and the untreated groups (avg. 0.6%). It was observed that the heat treatment significantly modified the biological behaviour of the implanted wood. The changes of the wood by heat treatment showed a positive outcome concerning osteoconductivity of the material.


Assuntos
Regeneração Óssea/fisiologia , Temperatura Alta , Madeira/química , Animais , Cor , Feminino , Fêmur/citologia , Fêmur/diagnóstico por imagem , Implantes Experimentais , Coelhos , Radiografia , Fatores de Tempo
16.
Br J Anaesth ; 102(2): 227-33, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19112059

RESUMO

BACKGROUND: Entropy is an anaesthetic EEG monitoring method, calculating two numerical parameters: State Entropy (SE, range 0-91) and Response Entropy (RE, range 0-100). Low Entropy numbers indicate unconsciousness. SE uses the frequency range 0.8-32 Hz, representing predominantly the EEG activity. RE is calculated at 0.8-47 Hz, consisting of both EEG and facial EMG. RE-SE difference (RE-SE) can indicate EMG, reflecting nociception. We studied RE-SE and EMG in patients anaesthetized without neuromuscular blockers. METHODS: Thirty-one women were studied in propofol-nitrous oxide (P) or propofol-nitrous oxide-remifentanil (PR) anaesthesia. Target SE value was 40-60. RE-SE was measured before and after endotracheal intubation, and before and after the commencement of surgery. The spectral content of the signal was analysed off-line. Appearance of EMG on EEG was verified visually. RESULTS: RE, SE, and RE-SE increased during intubation in both groups. Elevated RE was followed by increased SE values in most cases. In these patients, spectral analysis of the signal revealed increased activity starting from low (<20 Hz) frequency area up to the highest measured frequencies. This was associated with appearance of EMG in raw signal. No spectral alterations or EMG were seen in patients with stable Entropy values. CONCLUSIONS: Increased RE is followed by increased SE at nociceptive stimuli in patients not receiving neuromuscular blockers. Owing to their overlapping power spectra, the contribution of EMG and EEG cannot be accurately separated with frequency analysis in the range of 10-40 Hz.


Assuntos
Anestésicos Combinados/farmacologia , Anestésicos Inalatórios/farmacologia , Anestésicos Intravenosos/farmacologia , Músculos Faciais/efeitos dos fármacos , Monitorização Intraoperatória/métodos , Adolescente , Adulto , Eletroencefalografia/efeitos dos fármacos , Eletromiografia/efeitos dos fármacos , Eletromiografia/métodos , Entropia , Músculos Faciais/fisiologia , Feminino , Humanos , Intubação Intratraqueal , Laparoscopia , Pessoa de Meia-Idade , Bloqueio Neuromuscular , Óxido Nitroso/farmacologia , Piperidinas/farmacologia , Propofol/farmacologia , Estudos Prospectivos , Remifentanil , Processamento de Sinais Assistido por Computador , Adulto Jovem
17.
J Biomed Mater Res B Appl Biomater ; 87(1): 73-6, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18433009

RESUMO

In a study on 25 patients with verified benign bone tumors, bioactive glass (BG) and autogenous bone (AB) were used as bone-graft substitutes. The patients were randomized into two groups according to the filling material. Blood samples were taken both preoperatively, at 2 weeks, and 3, 8, 12, 24, and 36 months postoperatively, for evaluation of silicon concentration in blood. In the determination, direct current plasma atomic emission spectroscopy was used. No significant difference in blood silicon concentration between the BG group or the AB group could statistically be observed (p = 0.5400), and neither did the size of the bone tumor (p = 0.4259) nor the follow-up time affect the results (p = 0.2094). Concentration of osteocalcin in blood was significantly higher for large cysts (p < 0.0001). The filler material (BG or AB) did not affect the osteocalcin concentration level in blood.


Assuntos
Neoplasias Ósseas/cirurgia , Substitutos Ósseos/uso terapêutico , Transplante Ósseo , Vidro , Substitutos Ósseos/química , Humanos , Estudos Longitudinais , Teste de Materiais , Osteocalcina/sangue , Silício/sangue , Nicho de Células-Tronco/patologia , Transplante Autólogo
18.
Cell Tissue Bank ; 5(4): 213-21, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15591824

RESUMO

The aim of this study was to describe and evaluate the significance of a porous surface with bioactive glass granules (S53P4) covering an artificial bulk material based on polymethylmetacrylate (PMMA) and fibre-reinforced composite (FRC) technology. Effort was focused particularly on characters of the porous surface and biomechanical properties of the material in vitro , and test in vivo the implant in reconstruction in an experimental long bone segment defect model. The defect, 10 mm in length, created in the shaft of rabbit tibia, was reconstructed by the implant and fixed by intramedullary K-wires. The implant was incorporated within 4 weeks by new bone growth from the host bone covering particularly its posterior surface and cortex/implant junctions with bridging trabecular bone. Later, at 8 weeks, new bone was found also at the cortex/implant interface and in the medullary canal of the implant. Histometric measurements revealed direct bone/implant surface contact in 34% at the interface. Bioactive glass granules in the porous surface evoked the most direct contact with bone. The implants manufactured from PMMA only served as a control group, and showed significantly lower osteoconductive properties. Biomechanical measurements in vitro of fibre-reinforced PMMA specimens revealed values for bending strength and the flexural modulus to match them to human bone. This artificial bulk bone material based on PMMA/FRC technology seems to have proposing properties to be used as a bone substitute on load-bearing conditions.


Assuntos
Substitutos Ósseos , Vidro , Polimetil Metacrilato , Teste de Materiais , Microscopia Eletrônica de Varredura , Próteses e Implantes
19.
J Mater Sci Mater Med ; 14(4): 365-72, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15348461

RESUMO

Bioactive glass granules of three different compositions, regarding particularly Si- and Al- content (S53P4, S59.7P2.5, S52P3) and of two different granule sizes (200-250 microm and 630-800 microm) were implanted for 4 and 8 weeks in the distal part of rabbit femur. The effect of glass composition and granule size on bone formation was studied. The results were evaluated using histology, computerized histomorphometry, scanning electron microscopy and energy dispersive X-ray analysis, and used for mathematical description of bone formation. The results showed that both the composition of the glass and the granule size of the granules, have influence on bone growth from the surrounding tissue. Glass S53P4, which from previous observations is known to be an effective bioactive glass and widely used in the Biomaterial Project of Turku, Finland, showed bone bonding and increasing bone growth between the granules. Glass S59.7P2.5 which due to its high Si-content should be inert, showed bone bonding. At 4 weeks the bone growth was significantly more abundant in bone defects filled with large granules (630-800 microm) than in defects filled with small granules (200-250 microm). Glass S52P3 with an alumina content of 3 wt %, showed good bone conduction, possibly even bone bonding for granules of 630-800 microm size. Granules of 200-250 microm with a high alumina content at the surface of the reaction layer, showed hardly any bone contact at all. This data, therefore, gives new information concerning bone bonding and osteoconduction of bioactive glasses with a high silica or alumina content.

20.
Chir Organi Mov ; 88(2): 143-8, 2003.
Artigo em Inglês, Italiano | MEDLINE | ID: mdl-14735821

RESUMO

An evaluation of the long-term survival rate of 25 osteoarticular allografts was made. Clinical analysis was based on the Mankin scale and the Musculoskeletal Tumor Society (MSTS) Grading system. After a mean follow-up time of 15 years 76% of the osteoarticular allografts had good or excellent rating. The MSTS scale revealed a mean score of 89% for those 20 grafts still functioning according to their primary purpose. Allograft related complications occurred in 32% of the cases being most common among malignant cases. Due to the rather good long-term results, osteoarticular allografts can still be recommended for hemicondylar allograft reconstruction in benign lesions.


Assuntos
Sobrevivência de Enxerto , Articulações/transplante , Adulto , Cadáver , Seguimentos , Humanos , Fatores de Tempo
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