Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 95
Filtrar
1.
Geburtshilfe Frauenheilkd ; 76(8): 875-881, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-27582581

RESUMEN

INTRODUCTION: Endometriosis is a heterogeneous disease characterized by a range of different presentations. It is usually diagnosed when patients present with pain and/or infertility, but it has also been diagnosed in asymptomatic patients. Because of the different diagnostic approaches and diverse therapies, time to diagnosis can vary considerably and the definitive diagnosis may be delayed, with some cases not being diagnosed for several years. Endometriosis patients have many unmet needs. A systematic registration and follow-up of endometriosis patients could be useful to obtain an insight into the course of the disease. The validation of biomarkers could contribute to the development of diagnostic and predictive tests which could help select patients for surgical assessment earlier and offer better predictions about patients who might benefit from medical, surgical or other interventions. The aim is also to obtain a better understanding of the etiology, pathogenesis and progression of the disease. MATERIAL AND METHODS: To do this, an online multicenter documentation system was introduced to facilitate the establishment of a prospective multicenter case-control study, the IEEP (International Endometriosis Evaluation Program) study. We report here on the first 696 patients with endometriosis included in the program between June 2013 and June 2015. RESULTS: A documentation system was created, and the structure and course of the study were mapped out with regard to data collection and the collection of biomaterials. CONCLUSION: The documentation system permits the history and clinical data of patients with endometriosis to be recorded. The IEEP combines this information with biomaterials and uses it for scientific studies. The recorded data can also be used to evaluate clinical quality control measures such as the certification parameters used by the EEL (European Endometriosis League) to assess certified endometriosis centers.

2.
J Biomech ; 44(4): 600-6, 2011 Feb 24.
Artículo en Inglés | MEDLINE | ID: mdl-21130459

RESUMEN

Force-elongation responses of the human abdominal wall in the linea alba region were determined by tensile tests in which the linea alba was seen to exhibit a nonlinear elastic, anisotropic behavior as is frequently observed in soft biological tissues. In addition, the geometry of the abdominal wall was determined, based on MRI data. The geometry can be specified by principal radii of curvature in longitudinal of approximately 470 mm and in the transverse direction of about 200 mm. The determined radii agree with values found in other studies. Mechanical stresses, deformations and abdominal pressures for load cases above 6% elongation can be related using Laplace's formula and our constitutive and geometrical findings. Results from uni- and biaxial tensile tests can thus be compared using this model. Calculations confirm that abdominal pressures of approximately 20 kPa correspond to related biaxial forces of about 3.4N/mm in the transverse and 1.5 N/mm in the longitudinal direction. Young's moduli can be calculated with respect to the uniaxial as well as the biaxial loading. At these physiological loadings, a compliance ratio of about 2:1 between the longitudinal and transversal directions is found. Young's moduli of about 50 kPa occur in transversal direction and of about 20 kPa in longitudinal direction at transverse and longitudinal strains both in the order of 6%. These findings coincide with results from other investigations in which the properties of the abdominal wall have been examined.


Asunto(s)
Fascia/anatomía & histología , Fascia/fisiología , Modelos Biológicos , Pared Abdominal , Simulación por Computador , Módulo de Elasticidad/fisiología , Dureza/fisiología , Humanos , Técnicas In Vitro , Estrés Mecánico , Resistencia a la Tracción/fisiología
3.
Hum Reprod ; 22(3): 815-28, 2007 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-17114196

RESUMEN

BACKGROUND: Follicular fluid meiosis-activating sterol (FF-MAS) protects young oocytes from precocious chromatid separation (predivision). Reduced expression of cohesion and checkpoint proteins and predivision has been hypothesized to occur in age-related aneuploidy in oocytes. METHODS: To know whether FF-MAS also protects aged oocytes from predivision and from age-related non-disjunction, we analysed chromosome constitution in mouse oocytes matured spontaneously with or without 10 microM FF-MAS and in hypoxanthine (HX)-arrested young and aged oocytes induced to resume maturation by FF-MAS. Messenger RNA for checkpoint protein MAD2 and cohesion protein SMC1beta was compared between oocytes matured with or without FF-MAS. RESULTS: Aged oocytes possessed many bivalents with single distal chiasma at meiosis I. Predivision was especially high in aged oocytes cultured sub-optimally to metaphase II in alpha-minimum essential medium (alpha-MEM). FF-MAS reduced predivision significantly (P < 0.001) but neither reduced non-disjunction nor induced aneuploidy in aged oocytes. Polyploidy was high in FF-MAS-stimulated maturation, in particular in the aged oocytes (P > 0.001). Relative levels of Smc1beta mRNA appeared increased by maturation in FF-MAS, and mitochondrial clustering was restored. CONCLUSIONS: Sister chromatids of aged oocytes appear to be highly susceptible to precocious chromatid separation, especially when maturation is under sub-optimal conditions, e.g. in the absence of cumulus and FF-MAS. This may relate to some loss of chromatid cohesion during ageing. FF-MAS protects aged oocytes from predivision during maturation, possibly by supporting Smc1beta expression, thus reducing risks of meiotic errors, but it cannot prevent age-related non-disjunction. Aged oocytes appear prone to loss of co-ordination between nuclear maturation and cytokinesis suggesting age-related relaxed cell cycle control.


Asunto(s)
Colestenos/farmacología , Cromátides/fisiología , Segregación Cromosómica/fisiología , Meiosis/efectos de los fármacos , Oocitos/fisiología , Envejecimiento , Animales , Proteínas de Ciclo Celular/biosíntesis , Senescencia Celular , Segregación Cromosómica/efectos de los fármacos , Femenino , Hipoxantina/farmacología , Proteínas Mad2 , Ratones , Ratones Endogámicos CBA , Compuestos Orgánicos , Poliploidía
4.
Artículo en Inglés | MEDLINE | ID: mdl-17824173

RESUMEN

Gender differences in the development of cardiovascular disease suggested for a protective function of estrogens in heart disease. The negative or neutral outcome of clinical trials on hormone replacement therapy provides clear evidence that the role of female sex hormones in the cardiovascular system is more complex than previously thought. In particular, the function of estrogens can not be understood without detailed knowledge on the specific function of both estrogen receptor subtypes in the heart and in the vasculature. In here, we review recent studies on subtype selective ERalpha and ERbeta agonists in different animal models of hypertension, cardiac hypertrophy and vascular inflammation. The results indicate that the activation of specific ER subtypes confers specific as well as redundant protective effects in hypertensive heart disease that might ultimately translate into novel treatment options for hypertensive heart disease.


Asunto(s)
Sistema Cardiovascular/efectos de los fármacos , Receptor alfa de Estrógeno/agonistas , Receptor beta de Estrógeno/agonistas , Moduladores Selectivos de los Receptores de Estrógeno/farmacología , Animales , Cardiomegalia/tratamiento farmacológico , Receptor alfa de Estrógeno/fisiología , Receptor beta de Estrógeno/fisiología , Humanos , Hipertensión/tratamiento farmacológico , Ratas , Ratas Endogámicas SHR
5.
Biomed Tech (Berl) ; 49(9): 233-7, 2004 Sep.
Artículo en Alemán | MEDLINE | ID: mdl-15493130

RESUMEN

The subject of this paper is to present a technical description of a high-performance, modular research device, designed and constructed with the aim of enabling the non-invasive investigation of the passive electrical properties of biological tissue in the frequency range 1 kHz-1 MHz. The modular hardware- and software of the device makes the system highly flexible when it comes to applying a wide range of methods for the non-invasive analysis of the state and function of biological tissues and evaluating them in a clinical setting. Furthermore, the concept also makes it possible to combine the modules in new ways for new applications, to accommodate future developments in bio-impedance research.


Asunto(s)
Impedancia Eléctrica , Monitoreo Ambulatorio/instrumentación , Sistemas de Atención de Punto , Procesamiento de Señales Asistido por Computador/instrumentación , Análisis Espectral/instrumentación , Telemetría/instrumentación , Tomografía/instrumentación , Conversión Analogo-Digital , Computadores , Electrodos , Diseño de Equipo , Humanos , Programas Informáticos
6.
Biomed Tech (Berl) ; 49(7-8): 194-8, 2004 Aug.
Artículo en Alemán | MEDLINE | ID: mdl-15481406

RESUMEN

The use of impedance spectroscopy as a diagnostic tool for the investigation of biological objects involves the consideration of numerous parameters impacting on measuring accuracy. This paper describes a calibration method for multichannel instruments that reduces the non-inconsiderable influence of frequency response variations between the channels, thus significantly increasing measuring accuracy. The method is tested in a recently developed, high-resolution, multi-channel bio-impedance analyser. Reduction of the measuring error is demonstrated, and the magnitude and phase resolution is quantified. The advantage of this method lies in its applicability to existing systems. Furthermore, an additional calibration impedance is not needed.


Asunto(s)
Algoritmos , Impedancia Eléctrica , Análisis Espectral/instrumentación , Análisis Espectral/métodos , Animales , Calibración , Humanos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
8.
Rev. Soc. Venez. Microbiol ; 23(2): 163-165, jul.-dic. 2003. tab
Artículo en Español | LILACS | ID: lil-412185

RESUMEN

La esporotricosis es la enfermedad causada por el hongo Sporothrix schenckii. El diagnóstico se obtiene por la demostración de los cuerpos asteroides en las lesiones, o por la identificación de S. schenkii en el cultivo. Existe una prueba, LA-SPOROTRIX ANTIBODY SYSTEM de IMMY, de aglutinación cualitativa de partículas de látex, para determinar la presencia de anticuerpos de tipo IgM a partir del suero en pacientes con esporotricosis. El objetivo de este estudio fue evaluar la utilidad de esta prueba en el diagnóstico certero de esporotricosis cutánea. Se analizaron 87 sueros, 10 con esporotricosis, 17 con leishmaniasis, 20 con paracoccidioidomicosis, 20 con histoplasmosis y 20 sueros de individuos sanos. La sensibilidad de la prueba fue del 100 por ciento con una especificidad del 54 por ciento. Esto sugiere que es una técnica útil para excluir el diagnóstico de esta enfermedad; sin embargo, no es la más apropiada para un diagnóstico confirmatorio


Asunto(s)
Diagnóstico , Sporothrix , Esporotricosis , Microbiología , Venezuela
9.
Hum Reprod ; 18(9): 1908-17, 2003 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-12923148

RESUMEN

BACKGROUND: Follicular fluid meiosis-activating sterol (FF-MAS) overcomes hypoxanthine (HX)-mediated meiotic arrest in mammalian oocytes. METHODS: In order to determine whether chromosome segregation was normal in oocytes matured in FF-MAS, the development, chromosomal constitution and chromosome alignment was analysed in spontaneously matured as well as HX-arrested mouse oocytes cultured in the absence or presence of FF-MAS. RESULTS: FF-MAS-induced meiotic maturation was significantly less effective compared with spontaneous maturation in supporting cytokinesis ( approximately 40 and approximately 90% polar body formation respectively). The majority of oocytes stimulated by FF-MAS to overcome the HX block developed to metaphase II (MII), but 23.4% of meiosis II oocytes were diploid. Chromosomes were well aligned on the spindle, and hyperploidy was low in spontaneously matured oocytes and HX-arrested oocytes cultured with or without FF-MAS. Unexpectedly, almost 40% of spontaneously matured MII oocytes contained chromatids/monads. Precocious loss of chromatid cohesion was significantly reduced in spontaneously matured as well as HX-arrested oocytes cultured in the presence of FF-MAS but not lanosterol. CONCLUSIONS: FF-MAS induces full nuclear maturation to MII, and chromosomes segregate with high fidelity. However, in delayed FF-MAS-stimulated meiotic maturation, anaphase I may occur in the absence of cytokinesis. FF-MAS appears to protect mammalian oocytes from precocious chromatid segregation.


Asunto(s)
Colestenos/farmacología , Segregación Cromosómica/efectos de los fármacos , Citoprotección , Oocitos/efectos de los fármacos , Oocitos/fisiología , Animales , Núcleo Celular/fisiología , Células Cultivadas , Senescencia Celular , Cromátides/efectos de los fármacos , Cromátides/fisiología , Cromosomas/efectos de los fármacos , Cromosomas/fisiología , Medios de Cultivo/farmacología , Diploidia , Femenino , Hipoxantina/farmacología , Meiosis/efectos de los fármacos , Ratones , Ratones Endogámicos CBA , Ploidias , Huso Acromático/efectos de los fármacos , Huso Acromático/fisiología , Factores de Tiempo
10.
Rev. Soc. Venez. Microbiol ; 22(2): 136-140, jul.-dic. 2002.
Artículo en Español | LILACS | ID: lil-356822

RESUMEN

La prueba de la ureasa constituye una de las pruebas preliminares destinadas al diagnóstico diferencial de las levaduras, para la misma se utiliza el medio de agar urea de Christensen, con la desventaja de que éste es un medio costoso y de compleja elaboración. El propósito de este estudio fue evaluar la utilidad del calcio urea de Stuart para realizar esta prueba, el cual es un medio ampliamente usado en el área de Bacteriología, y su elaboración en sencilla. Para tal fin, se estudió el comportamiento de 104 cepas de levaduras pertenecientes a los géneros Candida, Cryptococcus, Rhodotorula, Trichosporon y Saccharomyces, en ambos medios. Los resultados no mostraron diferencia alguna entre el uso de los dos medios.


Asunto(s)
Urea , Microbiología , Venezuela
11.
Mycoses ; 45(9-10): 351-7, 2002 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-12421280

RESUMEN

In pathogenicity studies of 31 Paracoccidioides brasiliensis isolates preserved using Castellani's method we intraperitoneally inoculated 104 young adult hamsters and found laminated concentric structures and calcified appearance that resembled Schaumann bodies, in 43 of them, especially in animals with apparently good condition. We characterized these structures histologically and histochemically using different stains (PAS, Grocott, haematoxylin-eosin, Von Kossa). The Von Kossa staining revealed calcium in these structures. Similar structures have been described in patients with sarcoidosis and also in hamsters inoculated with P. brasiliensis. We found no correlation between the presence of these calcifications and serum calcium levels.


Asunto(s)
Paracoccidioides/citología , Paracoccidioides/patogenicidad , Paracoccidioidomicosis/microbiología , Animales , Anticuerpos Antifúngicos/análisis , Calcinosis , Cricetinae , Modelos Animales de Enfermedad , Granuloma/inmunología , Granuloma/patología , Paracoccidioides/crecimiento & desarrollo , Paracoccidioides/inmunología , Paracoccidioidomicosis/patología , Coloración y Etiquetado/métodos
12.
Clin Biomech (Bristol, Avon) ; 16(8): 702-5, 2001 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11535352

RESUMEN

OBJECTIVE: A new design of intra-medullary nailing fixation is investigated in this study. The strength properties of the new design are compared to the standard fixation method. DESIGN: The bone-implant-compound is examined by using experimental methods. BACKGROUND: Failure of bone substance in the region of the interlocking screws is a complication in particular in treating fractures of osteoporotic bone. A new additional implant is investigated, which should improve the fracture fixation of the bone-implant-compound. METHODS: The experiments were performed by using an universal testing machine. The bone-implant-compound was loaded by different compressive forces and the stiffness of the bone-implant-compound was measured. The maximum force to failure was also determined by a destructive test. RESULTS: The experimental results indicate that the additional implant increases the stiffness of the bone-implant-compound. The highest stress concentrations occur at the drill holes of the interlocking screws. Failure of the bone-implant-compound occurs at higher maximum forces by using the additional implant. CONCLUSIONS: The additional implant improves the strength of the bone-implant-compound. In the case of osteoporotic bone, the use of the additional implant is recommended. RELEVANCE: In surgical treatment of fractured femurs, the fracture is bridged by a medullary nail fixed with interlocking screws. Failure of bone substance in the region of the interlocking screws is the most common complication in the treatment of osteporotic bone. With the aim of preventing this complication, a new additional implant is developed and investigated.


Asunto(s)
Clavos Ortopédicos , Fracturas del Fémur/fisiopatología , Fracturas del Fémur/cirugía , Fijación Intramedular de Fracturas/métodos , Fenómenos Biomecánicos , Humanos
13.
J Org Chem ; 66(19): 6339-43, 2001 Sep 21.
Artículo en Inglés | MEDLINE | ID: mdl-11559184

RESUMEN

The first rhodium-catalyzed intermolecular hydroamination of alkynes is presented. Terminal alkynes react efficiently with anilines in the presence of cationic rhodium(I) catalysts under very mild reaction conditions (e.g., base and acid free at room temperature) to yield up to 99% of the corresponding imines. An easy one-pot protocol for the synthesis of secondary amines was developed by combining this alkyne amination reaction with in situ addition of organolithium reagents.

14.
Biomed Tech (Berl) ; 46(4): 91-5, 2001 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-11388040

RESUMEN

Two widely used electrical tomography systems, the Sheffield Mark I and the DAS-01P, were quantitatively evaluated and compared to the newly developed Goe-MF system. The performance was quantified using a hardware phantom which closely matches the real input and transfer impedances of the human thorax and allows measurements equivalent to different states of lung inflation. Our results demonstrate that adequate averaging is necessary for noise reduction for the Mark I and especially for the DAS-01P system to get meaningful results even in visualizing maximal respiratory manoeuvres. The Goe-MF system showed a notably improved signal-to-noise ratio which allows also dynamic measurements at low levels of lung volume changes, e.g., in intensive care lung injury patients.


Asunto(s)
Cardiografía de Impedancia/instrumentación , Ventilación Pulmonar/fisiología , Calibración , Cuidados Críticos , Humanos , Pulmón/fisiopatología , Lesión Pulmonar , Mediciones del Volumen Pulmonar/instrumentación , Modelos Cardiovasculares , Reproducibilidad de los Resultados , Procesamiento de Señales Asistido por Computador/instrumentación
15.
Mycopathologia ; 149(2): 63-8, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11265163

RESUMEN

Oropharyngeal candidiasis caused by various species of Candida is one of the most common infections in HIV seropositive or AIDS patients. Drug resistance among these yeasts is an increasing problem. We studied the frequency of resistance profile to fluconazole, itraconazole, ketoconazole, amphotericin B and terbinafine of 137 isolates of Candida sp. From HIV positive or AIDS patients with oropharyngeal candidiasis at Instituto de Inmunología, U.C.V. and the Hospital "Jose Ignacio Baldó", Caracas Venezuela, using the well diffusion susceptibility test (Magaldi et al.). We found that nearly 10% of C. albicans isolates were primarily fluconazole resistant, 45% of C. albicans isolates from patients with previous treatment were resistant to fluconazole, of which 93% showed cross-resistance to itraconazole, and even about 30% of C. tropicalis (n = 13) were resistant to fluconazole and/or itraconazole. To this respect, several recent reports have been described antifungal cross-resistance among azoles. Therefore, we consider that C. tropicalis should be added to the growing list of yeast in which antifungal drug resistance is common. This report could be useful for therapeutic aspect in AIDS patients with oral candidiasis.


Asunto(s)
Infecciones Oportunistas Relacionadas con el SIDA/microbiología , Antifúngicos/farmacología , Candida albicans/efectos de los fármacos , Candidiasis/microbiología , Seropositividad para VIH/microbiología , Enfermedades Faríngeas/microbiología , Síndrome de Inmunodeficiencia Adquirida/complicaciones , Síndrome de Inmunodeficiencia Adquirida/microbiología , Anfotericina B/farmacología , Azoles/farmacología , Candidiasis/complicaciones , Farmacorresistencia Microbiana , Seropositividad para VIH/complicaciones , Humanos , Pruebas de Sensibilidad Microbiana/métodos , Naftalenos/farmacología , Enfermedades Faríngeas/complicaciones , Terbinafina
17.
Biol Reprod ; 64(2): 418-24, 2001 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-11159342

RESUMEN

Meiosis-activating sterols (MAS) have been found to induce meiotic maturation in mouse oocytes in vitro. In the present study we have extended these observations by investigating the effects of follicular fluid MAS (FF-MAS) on rat oocyte maturation in vitro and ex vivo. Rat oocytes freed from their follicles were cultured with FF-MAS (0 microM, 1 microM, 3 microM, 10 microM, 30 microM) for 22 h in a medium containing the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX; 250 microM). A dose-dependent significant increase in germinal vesicle breakdown (GVB) was observed after adding FF-MAS to the culture medium in both cumulus-enclosed (CEO) and denuded (DO) oocytes. A time course study (0, 3, 8, 14, and 22 h) showed a significant increase in GVB after 14 h when DO and CEO were cultured in the presence of 10 microM FF-MAS + 250 microM IBMX. Furthermore immature rats were primed with eCG (20 IU) and 48 h later perfused ex vivo for 12 h in a recirculating system with either FF-MAS (0 microM, 10 microM, 30 microM, 60 microM), cholesterol (60 microM), or LH (0.2 microg/ml) in the presence of 200 microM IBMX, respectively. In addition, ovarian perfusion was carried out with FF-MAS (30 microM, 60 microM) or 0.2 microg/ml LH in the absence of IBMX. After 12 h, oocytes were freed from the ovaries and checked for GVB. By using the ex vivo perfused rat ovary, we found that FF-MAS, starting at 30 microM, was dose-dependently able to overcome IBMX-induced meiotic arrest leading to a comparable increase in GVB as was observed for LH. Furthermore, it was found that FF-MAS in the absence of IBMX was also able to induce meiotic maturation. Our data are consistent with the notion that the maturation-inducing effects of FF-MAS are mediated by different mechanisms compared to spontaneous maturation.


Asunto(s)
Colestenos/farmacología , Meiosis/efectos de los fármacos , Oocitos/crecimiento & desarrollo , 1-Metil-3-Isobutilxantina/farmacología , Animales , Colesterol/farmacología , Relación Dosis-Respuesta a Droga , Femenino , Técnicas In Vitro , Oocitos/efectos de los fármacos , Ovario/fisiología , Perfusión , Inhibidores de Fosfodiesterasa/farmacología , Ratas , Estimulación Química
18.
Z Gerontol Geriatr ; 34(6): 509-16, 2001 Dec.
Artículo en Alemán | MEDLINE | ID: mdl-11828893

RESUMEN

UNLABELLED: We present an analysis of the risk factors, the origin and the nursing and medical practice of 140 deaths with high-grade pressure sores which had been detected by post-mortem examination before cremation. METHODS: All available nursing and medical records from nursing homes and hospitals were screened; in addition, relatives and head nurses were interviewed. The data sources were screened for individual risk factors, information about pressure sore prevention and treatment activities by nursing staff and general practitioners. Moreover, the utilization of pressure relieving devices for patients before and after development of the final decubitus was analyzed. RESULTS: More than 50% of the pressure ulcers had been incident in nursing homes. The mean duration of the disease was 307 days (median duration 123 days); the maximum duration ranged up to about 6 years. As far as it could be judged from the nursing records, there was a shortfall of nursing quality in terms of prevention efforts which appeared to be frequently inadequate in relation to the risk profile of the residents. Standardized pressure sore record files were missing in most of the cases. General practitioners were not involved in the treatment in 20% of all cases; some of them prescribed an obsolete wound management. In this study 52% of the patients had been classified into the maximum grade within the three-stage German nursing care insurance scheme. In cases of private care information about utilization of financial support and of professional help should be enforced. DISCUSSION: Being an indicator of nursing quality, shortfalls of prevention measures should be combatted by a broad pattern of quality management strategies which could be adapted from the clinical sector.


Asunto(s)
Úlcera por Presión/enfermería , Cuidado Terminal , Adulto , Anciano , Anciano de 80 o más Años , Medicina Familiar y Comunitaria , Femenino , Hogares para Ancianos , Humanos , Masculino , Persona de Mediana Edad , Casas de Salud , Personal de Enfermería en Hospital , Grupo de Atención al Paciente , Úlcera por Presión/etiología , Úlcera por Presión/prevención & control , Factores de Riesgo
19.
Biomed Tech (Berl) ; 46(12): 351-4, 2001 Dec.
Artículo en Alemán | MEDLINE | ID: mdl-11820162

RESUMEN

In the present study, the fixation system of a femoral medullary nail connection was investigated. In surgical treatment of fractured femurs, the fracture is bridged by a medullary nail that is fixed by interlocking screws in the bone. Bone failure around these screws is the most common complication associated with the treatment of fractures of osteoporotic bone. The present study analyses the stresses present in the region of the implant/bone system. Three-dimensional finite element models were generated, a nonlinear structure analysis performed, and the stresses at material interfaces investigated. The highest concentration of stresses is to be found in the middle of the interlocking screws and the holes drilled in the bone. This is in agreement with the results of experimental investigations.


Asunto(s)
Tornillos Óseos , Fracturas del Fémur/fisiopatología , Análisis de Elementos Finitos , Fijación Intramedular de Fracturas/instrumentación , Osteoporosis/fisiopatología , Fenómenos Biomecánicos , Gráficos por Computador , Análisis de Falla de Equipo , Fracturas del Fémur/cirugía , Fémur/fisiopatología , Fémur/cirugía , Humanos , Imagenología Tridimensional , Osteoporosis/cirugía
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA