ABSTRACT
Se presenta la experiencia del Servicio de Partes Blandas y Tumores Oseos del Hospital Oncológico Padre Machado, de Caracas, en el manejo de los tumores del esqueleto, por un período de 20 años (1984-2003). la evaluación de la experiencia fue retrospectiva, con un análisis objetivo estadístico lineal, presentándose el espectro de la patología atendida, y la diversidad de alternativas terapéuticas quirúrgicas utilizadas. Se reporta una incidencia preferencial de esta patología en los miembros inferiores (58,58 por ciento), particularmente alrededor de la rodilla (fémur distal y tibia proximal). El grupo de tumores más frecuentemente observado fue el de formadores de tejido óseo (20,95 por ciento, seguido de los formadores de tejido cartilaginoso (14,79 por ciento), tumor de células gigantes (9,93 por ciento), y las lesiones pseudotumorales (5,85 por ciento). Entre los tumores formadores de tejido óseo llama la atención la alta incidencia de las variedades malignas (90,52 por ciento); miemtras que en los formadores de tejido cartilaginoso, las variedades benignas fueron las más frecuentes (69,80 por ciento). Entre los tipos de cirugía realizadas, una proporción importante tuvo finalidad diagnóstica (58,41 por ciento), aunque en muchas de ellas la intención fue simultánea o adicionalmente terapéutica (escisión, drenaje, relleno, etc.). Entre las cirugías con finalidad terapéutica, hay una amplia diversidad de opciones, destacándose, la posibilidad de la práctica de una cirugía preservadora, siempre que se respeten los principios oncológicos quirúrgicos. se resalta la importancia del manejo de esta patología en centros espeializados.
The experience of the Service of Solft Tissue and Bone Tumors, of the Oncology Hospital Padre Machado, Caracas, in the management of the tumors affecting the skeleton, for a period of 20 years (1984-2003), is presented. The evaluation of this experience was a retrospective revision, with an objective statistics lineal analysis, showing the spectrum of the pathology, and the therapeutic surgical alternatives utilized. The report shows a higher incidence of this pathology affecting the lower limbs (58,58 per cent), particular..around the knee joint (distal femur and proximal tibia). The most frequent type of tumor was the bone forming tumors group (20.95 per cent), followed by the cartilaginous tissue forming tumors group (14.79 per cent, giant cell tumors (9.93 per cent), and pseudotumoral lesions (5.85 per cent). Among the bone forming tumor group, called our attention the prevalence of the malignant variety (90.52 per cent); whereas in the cartilaginous tissue forming type, the bening options were seen more frequently (69.80 per cent). Looking at the performed surgeries, an important proportion had a diagnostic goal (58.41 per cent), although many of them allowed a therapeutic solution at the same time (resection, drainage, folling defects, etc). Among the surgical options with a therapeutic goal, we performed a very large variety of them, proposing limb presenvation when the surgical oncology principles could be respected. The importance of treating this pathology in specialized centers is underlined.
Subject(s)
Humans , Male , Female , Medicine , Neoplasms, Bone Tissue/surgery , Neoplasms, Bone Tissue/pathology , Osteochondroma/surgery , Osteochondroma/pathology , Biopsy/methods , Giant Cells/physiology , Orthopedic Equipment , Skeleton , Medical OncologyABSTRACT
Outward current oscillations associated with transient membrane hyperpolarizations were induced in murine macrophage polykaryons by membrane depolarization in the absence of external Na+. Oscillations corresponded to a cyclic activation of Ca2+ -dependent K+ currents (IKCa) probably correlated with variations in intracellular Ca2+ concentration. Addition of external Na+ (8mM) immediately abolished the outward current oscillations, suggesting that the absence of the cation is necessary not only for their induction but also for their maintenance. Oscillations were completely blocked by nisoldipine. Ruthenium red and ryanodine reduced the number of outward current cycles in each episode, whereas quercetin prolonged the hyperpolarization 2- to 15-fold. Neither low molecular weight heparin nor the absence of a Na+ gradient across the membrane had any influence on oscillations. The evidence suggests that Ca+ entry through a pathway sensitive to Ca2+ channel blockers is elicited by membrane depolarization in Na+ -free medium and is essential to initiate oscillations, which are also dependent on the cyclic release of Ca2+ from intracellular Ca2+ -sensitive stores; Ca2+ ATPase acts by reducing intracellular Ca2+, thus allowing slow deactivation of IKCa. Evidence is presented that neither a Na+/Ca2+ antiporter nor Ca2+ release from IP3 -sensitive Ca2+ stores participate directly in the mechanism of oscillation.