[Osteoid osteoma of zygomatic bone: Case report and literature review]. / Ostéome ostéoïde du corps de l'os zygomatique : à propos d'un cas et revue de la littérature.

INTRODUCTION: Osteoid osteoma is a benign osseous tumor affecting mainly young men. Although it develops essentially in long bones, some cases occurring in face, mainly in mandible, were related. To our knowledge, only one single case was described in zygomatic bone. OBSERVATION: A 71-year-old man consulted for a right periorbital pain evolving since months with night recrudescence. The pain was not relieved by standard analgesics. Clinical examination was strictly normal. CT scan showed a low-density bone lesion surrounded by a peripheral osseocondensation line within the body of the right zygoma with intense uptake at bone scintigraphy. The patient benefited from surgical excision of the lesion. Pain stopped immediately. Histological examination assessed an osteoid osteoma. DISCUSSION: Zygomatic localization and late occurrence are rare concerning osteoid osteomas. Many ways of management have been reported but surgical excision remains the gold standard.

Lipoic acid stimulates bone formation in ovariectomized rats in a dose-dependent manner.

This study was undertaken to determine the osteotropic effect of different doses of lipoic acid (LA) on the mineralization of bone tissue in female Wistar rats with experimental osteopenia induced by bilateral ovariectomy. Fifty-six rats were randomly selected and submitted to either a sham operation (n = 8) or an ovariectomy (n = 48). The ovariectomized rats were randomly placed into two control groups, treated subcutaneously with either physiological saline or 17ß-estradiol in the dose of 4 µg/kg body mass per day, and four experimental groups that received LA subcutaneously in the doses of 12.5, 25, 50, and 100 mg/kg body mass per day (n = 8 in each group). After 28 days of experimental treatment, the rats were sacrificed, and body mass, total skeletal density, and body composition were recorded. Blood serum and isolated femora were stored for further analysis. Our results revealed that the osteoprotective effect of LA was dose-dependent and was observed in rats treated with 50 and 100 mg/kg of LA. Moreover, the LA applied to the ovariectomized rats in the dose of 50 mg/kg not only stopped the bone resorption, but stimulated its formation.

Aluminum and bone: Review of new clinical circumstances associated with Al(3+) deposition in the calcified matrix of bone.

Several decades ago, aluminum encephalopathy associated with osteomalacia has been recognized as the major complication of chronic renal failure in dialyzed patients. Removal of aluminum from the dialysate has led to a disappearance of the disease. However, aluminum deposit occurs in the hydroxyapatite of the bone matrix in some clinical circumstances that are presented in this review. We have encountered aluminum in bone in patients with an increased intestinal permeability (coeliac disease), or in the case of prolonged administration of aluminum anti-acid drugs. A colocalisation of aluminum with iron was also noted in cases of hemochromatosis and sickle cell anemia. Aluminium was also identified in a series of patients with exostosis, a frequent benign bone tumor. Corrosion of prosthetic implants composed of grade V titanium (TA6V is an alloy containing 6% aluminum and 4% vanadium) was also observed in a series of hip or knee revisions. Aluminum can be identified in undecalcified bone matrix stained by solochrome azurine, a highly specific stain allowing the detection of 0.03 atomic %. Colocalization of aluminum and iron does not seem to be the fruit of chance but the cellular and molecular mechanisms are still poorly understood. Histochemistry is superior to spectroscopic analyses (EDS and WDS in scanning electron microscopy).

Aplicación de los modelos mecanobiológicos en los procesos de regeneración ósea / Application of mechano-biological models in bone regeneration process

Los modelos computacionales constituyen una herramienta necesaria en las investigaciones científicas. En este trabajo se muestra la utilización de las nuevas tecnologías, a través del Método de los Elementos Finitos en la implementación de los modelos mecanobiológicos usados en ortopedia. Se exponen los principales modelos mecano-reguladores que aparecen en la bibliografía y se ejemplifican las ventajas que proporcionan las técnicas de modelación en el pronóstico de la formación de nuevo tejido óseo, como respuesta biológica del organismo debido a la aplicación de cargas externas(AU)

Computational models are a necessary tool in scientific researches. This paper deals with the use of new technologies, by using the Finite Element Method for the implementation of mechano-biological models used in orthopedic. Also the main mechano-regulator models are shown in this article, which are described in literature. On the other hand, the advantages provided by the modeling techniques during the prognosis of the new tissue formation, as a response of the organism to the application of external loads are stated by these authors(AU)

Les modèles informatisées constituent un outil nécessaire dans les recherches scientifiques. Dans ce travail, on montre lusage des nouvelles technologies, telle que la méthode des Éléments finis, dans la mise en application des modèles biomécaniques utilisés en orthopédie. On fait une révision des modèles mécano-régulateurs principaux apparus dans la littérature, et on met des exemples des bénéfices obtenus par les techniques de modélisation dans le pronostic de formation du nouveau tissu osseux comme réponse biologique du corps aux charges externes(AU)

Aplicación de los modelos mecanobiológicos en los procesos de regeneración ósea / Application of mechano-biological models in bone regeneration process / Mise en application des modèles biomécaniques dans les processus de régénération osseuse

Los modelos computacionales constituyen una herramienta necesaria en las investigaciones científicas. En este trabajo se muestra la utilización de las nuevas tecnologías, a través del Método de los Elementos Finitos en la implementación de los modelos mecanobiológicos usados en ortopedia. Se exponen los principales modelos mecano-reguladores que aparecen en la bibliografía y se ejemplifican las ventajas que proporcionan las técnicas de modelación en el pronóstico de la formación de nuevo tejido óseo, como respuesta biológica del organismo debido a la aplicación de cargas externas.

Computational models are a necessary tool in scientific researches. This paper deals with the use of new technologies, by using the Finite Element Method for the implementation of mechano-biological models used in orthopedic. Also the main mechano-regulator models are shown in this article, which are described in literature. On the other hand, the advantages provided by the modeling techniques during the prognosis of the new tissue formation, as a response of the organism to the application of external loads are stated by these authors.

Les modèles informatisées constituent un outil nécessaire dans les recherches scientifiques. Dans ce travail, on montre l’usage des nouvelles technologies, telle que la méthode des Éléments finis, dans la mise en application des modèles biomécaniques utilisés en orthopédie. On fait une révision des modèles mécano-régulateurs principaux apparus dans la littérature, et on met des exemples des bénéfices obtenus par les techniques de modélisation dans le pronostic de formation du nouveau tissu osseux comme réponse biologique du corps aux charges externes.

Tejido óseo esponjoso esterilizado con gas óxido de etileno / Spongy bone tissue sterilized with ethylene oxide gas / Tissu osseux spongieux stérilisé à l'oxyde d'éthylène gazeux

Objetivo: comprobar las propiedades esterilizantes del gas óxido de etileno sobre el hueso esponjoso empleado como implante en la clínica médica, fundamentalmente su eficacia para determinados microorganismos y el tiempo necesario de su uso en autoclave industrial. Métodos: se prepararon 54 porciones de tejido óseo esponjoso en forma de cubo separados en 3 grupos de 18 porciones cada uno. El primer grupo se empleó para evaluar un método de contaminación bacteriológica con cepas de microorganismos conocidos. El segundo y tercer grupo una vez contaminados con los microorganismos conocidos se sometieron a la acción del gas óxido de etileno en subgrupos de 6, durante 60, 90 y 120 min. Resultados: en el primer grupo el 100 % de las muestras contaminadas se presentaron positivas. En los grupos segundo y tercero la efectividad del gas óxido de etileno resultó de 100 % a los 120 min. Conclusión: este método es seguro, por lo que es apropiado para el empleo en la clínica médica.

Objective: verify the sterilizing properties of ethylene oxide gas over the spongy bone used for implants in medical practice, mainly its efficacy against certain microorganisms and the time required for sterilization in industrial autoclaves. Methods: 54 cube-shaped spongy bone tissue samples were prepared and distributed into 3 groups, each with 18 samples. The first group was used to evaluate a bacteriological contamination method with strains of known microorganisms. Upon contamination with the known microorganisms, the second and third groups were subjected to the effect of ethylene oxide gas in subgroups of 6 samples during 60, 90 and 120 minutes. Results: in the first group 100 % of the samples contaminated were positive. In the second and third groups, the effectiveness of ethylene oxide gas was 100 % at 120 minutes. Conclusion: this is a safe method appropriate for use in medical practice.

Objectif: confirmer les propriétés stérilisantes de l'oxyde d'éthylène gazeux sur l'os spongieux utilisé comme implant dans la clinique médicale, notamment son efficacité contre certains microorganismes, et le temps nécessaire pour l'utiliser dans un autoclave industriel. Méthodes: cinquante-et-quatre portions de tissu osseux spongieux ont été préparées sous forme de cube, et séparées en 3 groupes de dix-huit portions chacun. Le premier groupe a été utilisé pour évaluer une méthode de contamination bactériologique à souches de microorganismes connus. Une fois contaminés par des microorganismes connus, les deuxième et troisième groupes ont été soumis à l'action de l'oxyde d'éthylène gazeux en sous-groupes de 6 au cours de 60, 90 et 120 minutes. Résultats: dans le premier groupe, 100 % des échantillons contaminés ont été positifs. Dans les deuxième et troisième groupes, l'efficacité de ce gaz a réussi 100 % à 120 minutes. Conclusion: cette méthode est sure, donc appropriée, pour la clinique médicale.

Tejido óseo esponjoso esterilizado con gas óxido de etileno / Spongy bone tissue sterilized with ethylene oxide gas

Objetivo: comprobar las propiedades esterilizantes del gas óxido de etileno sobre el hueso esponjoso empleado como implante en la clínica médica, fundamentalmente su eficacia para determinados microorganismos y el tiempo necesario de su uso en autoclave industrial. Métodos: se prepararon 54 porciones de tejido óseo esponjoso en forma de cubo separados en 3 grupos de 18 porciones cada uno. El primer grupo se empleó para evaluar un método de contaminación bacteriológica con cepas de microorganismos conocidos. El segundo y tercer grupo una vez contaminados con los microorganismos conocidos se sometieron a la acción del gas óxido de etileno en subgrupos de 6, durante 60, 90 y 120 min. Resultados: en el primer grupo el 100 por ciento de las muestras contaminadas se presentaron positivas. En los grupos segundo y tercero la efectividad del gas óxido de etileno resultó de 100 por ciento a los 120 min. Conclusión: este método es seguro, por lo que es apropiado para el empleo en la clínica médica(AU)

Objective: verify the sterilizing properties of ethylene oxide gas over the spongy bone used for implants in medical practice, mainly its efficacy against certain microorganisms and the time required for sterilization in industrial autoclaves. Methods: 54 cube-shaped spongy bone tissue samples were prepared and distributed into 3 groups, each with 18 samples. The first group was used to evaluate a bacteriological contamination method with strains of known microorganisms. Upon contamination with the known microorganisms, the second and third groups were subjected to the effect of ethylene oxide gas in subgroups of 6 samples during 60, 90 and 120 minutes. Results: in the first group 100 percent of the samples contaminated were positive. In the second and third groups, the effectiveness of ethylene oxide gas was 100 percent at 120 minutes. Conclusion: this is a safe method appropriate for use in medical practice(AU)