BACKGROUND: At present, the researches on steroid-induced avascular necrosis of the femoral head are mostly concentrated on the treatment of formed necrosis. And there are fewer reports on how to prevent the ostoenecrosis of the femoral head in the course of steroid therapy.OBJECTIVE: To observe the effect of preventive medication on femoral head structure and blood flow in steroid-induced osteonecrosis.DESIGN: Randomized controlled experiment.SETTING: Department of Pharmacology, Department of Anatomy, Medical College of Shaoguan University; Department of Nuclear Medicine, Guangdong Province Yuebei People's Hospital.MATERIALS: Thirty adult New Zealand rabbits of either sex, whose body mass was (2.5±0.5) kg.METHODS: The experiment was carried out in the Central Laboratory,Medical College of Shaoguan University, the Department of Electron Microscope, the Northern Campus of Guangzhou, Sun Yat-sen University, and the Department of Nuclear Medicine, Guangdong Province Yuebei People's Hospital from April to July 2005. ①Thirty rabbits were divided randomly into 3 groups with 10 rabbits in each group: control group with intramuscular injection of 1 mL/kg normal saline twice a week and meanwhile, intragastric administration of normal saline(10 mL/d), steroid group with intramuscular injection of dexamethasone sodium phosphate(1 mL/kg) twice a week and meanwhile, intragastric administration of normal saline(10 mL/d),treatment group with intramuscular injection of dexamethasone sodium phosphate(1 mL/kg) twice a week and meanwhile, intragastric administration ofXuesaitong(25 mg/kg), Zhibituo(350 mg/kg) and alendronate(5 mg/kg)daily for 8 weeks. ②After 1 week of drug withdrawal, the blood flow of femoral head was measured in all the rabbits with radioactive microsphere technique, and the histological changes were observed under light microscope and electron microscope.MAIN OUTCOME MEASURES: ①Blood flow of the femoral head in each group.②Histological and morphological changes, and ultrastructure of the femoral head cartilage in each group.RESULTS: ①The blood flow in the treatment group was more than that in the steroid group[(0.261±0.042), (0.197±0.053) mL/(min·g), q=6.10,P ＜ 0.01]. Compared with the control group[(0.243±0.039) mL/(min ·g)],the difference was not significant. ②The number of empty bone lacunae in the treatment group was fewer significantly than that in the steroid group [(15.22±5.49), (24.78±7.87) pieces, q=6.35, P ＜ 0.01]. However, there was no difference between the treatment group and control gruop [(10.38±3.78)pieces].③In the treatment group, the bone cells were normal, the endoplasmic reticula were abundant and the cellular nuclei were of normal shape.In the steroid group, the bone cells contracted in volume, the pyknosis occurred, the chromatin gathered to the edge and the bone lacuna enlarged.CONCLUSION: While using steroid hormone for long, using Xuesaitong,Zhibituo and alendronate may elevate the blood flow of femoral head, improve the tissue structure of bone and prevent or lighten steroid-induced necrosis of femoral head.

OBJECTIVE To understand and use reasonably the strategy of prevention and management of overwhelming postsplenectomy infection(OPSI). METHODS According to intervention to patients with postsplenectomy by means of education,vaccination,antibotic prophylaxis after April 1998,clinical and follow-up data were reviewed and analyzed from 337 cases patients with traumatic splenectomy from Jan 1992 to Jan 2004,and correlative factors of four OPSI cases were further analyzed. RESULTS Incidence of OPSI descended obviously after intervention(P