RESUMEN
After hip prosthetic replacement, a progressive enlargement in the radiolucent area has often been observed around the implant, leading to loosening of the prosthesis. The purpose of this study was to investigate the mechanism of the radiolucent area formation. Radiolucent areas can be classified into either linear type or the erosive type, and these two types were compared histologically and biochemically. Interface membranes were obtained from patients at the time of surgery for revision of either cemented THA or cementless bipolar endprosthetic replacement. Histological specimens were stained by H.E., tartrate-resistant acid phosphate, and by the immunohistochemical reagents anti-macrophage antibody (CD 68), anti-T-lymphocyte (CD 3, CD 4, CD 8, CD 43), anti-interleukin-1 beta polyclonal antibody, anti-interleukin-6 polyclonal antibody, and anti-tumor necrosis factor-alpha polyclonal antibody. Biochemically, interleukin-1 beta, IL-6, IL-8, TNF-alpha were assayed by ELISA in the supernatant of homogenized samples and in organ culture media. Prostaglandin E2 was assayed by radioimmunoassay. The interfaces of the erosive type contained more debris (cement, high density polyethylene and metal), macrophages and multinucleated giant cells than the linear type. The interfaces of the linear type showed mainly fibrosis and necrosis. The levels of IL-6 and IL-8 in the homogenates and culture media from the erosive type were significantly higher than those from the linear type. We concluded that the bone resorption around the implant after hip prosthetic replacement occurred by two different pathways. One pathway involved the stimulation of macrophages by various debris and micromovement to form foreign body granulomas, which produced cytokines, prostaglandin E2 and metalloproteinase to resorb bone. The erosive type would arise from this pathway. The other possible mechanism involved a biomechanically unstable implant which caused bone necrosis probably by mechanical stress. The linear type may arise from this pathway.
Asunto(s)
Resorción Ósea/diagnóstico por imagen , Prótesis de Cadera , Resorción Ósea/metabolismo , Citocinas/metabolismo , Fibrosis , Granuloma de Cuerpo Extraño/etiología , Humanos , Macrófagos/inmunología , Metaloendopeptidasas/metabolismo , Necrosis , Prostaglandinas E/metabolismo , Falla de Prótesis , Radiografía , Estrés MecánicoRESUMEN
In order to elucidate the etiology of the loose shoulder, biochemical characteristics of deltoid and major pectoral muscles and skin collagen from patients with loose shoulder have been investigated. Amounts of soluble collagen, reducible cross-links of collagen and their precursors in both muscles and skin from the loose shoulder were found to be higher than those in the control. These data suggest that soft tissues, especially deltoid muscles, of patients with loose shoulder contain relatively immature collagen fibers compared with normal shoulders. In re-operation cases of the loose shoulder, the collagen fibers in skin were more immature, which may reflect the clinical features of the disease.
Asunto(s)
Colágeno/metabolismo , Inestabilidad de la Articulación/etiología , Músculos/metabolismo , Articulación del Hombro , Piel/metabolismo , Adolescente , Adulto , Aminoácidos/análisis , Niño , Colágeno/análisis , Humanos , Inestabilidad de la Articulación/metabolismo , Inestabilidad de la Articulación/fisiopatologíaRESUMEN
The bioavailability of five capsules of cyclandelate that are commercially available in Japan was determined in ten healthy volunteers by measuring mandelic acid (a main metabolite of cyclandelate) excreted in the urine. Bioinequivalence among the five capsules was demonstrated. The relative cumulative excretion of mandelic acid of the most poorly bioavailable capsule was 38% of the most highly bioavailable capsule. The effect of food on the bioavailability of these two capsules was investigated by use of two different kinds of food, one containing fat and one containing high carbohydrates but very low fat. The bioavailability of the two capsules was increased when subjects consumed both types of food before drug administration, although there was a greater effect on bioavailability with food containing fat. This suggests that the absorption of cyclandelate was incomplete in fasting subjects, even from the capsule with the highest bioavailability. Bioinequivalence between the two capsules remained after postprandial drug administration.