Calcium metabolism evaluated by 47Ca kinetics: estimation of dermal calcium loss.
Calcium metabolism evaluated by 47Ca kinetics: estimation of dermal calcium loss.
复制标题
通过 47Ca 动力学评估钙代谢：估计真皮钙损失。
作者：
P. Charles;F. Taagehøj Jensen;L. Mosekilde;H. Hvid Hansen
在正常志愿者（n = 15）和骨质疏松症患者（n = 12）、原发性甲状旁腺功能亢进症（n = 8）、成骨不全症（n = 5）、甲状腺髓样癌（n = 4）、甲状腺毒症（n = 2）和肥胖肠旁路患者（n = 11）中进行了 77 项钙平衡和 47Ca 周转研究。静脉注射 20 微居里的 47Ca 后，获得两条 47Ca 保留曲线：R1(t) 直接在全身计数器上测量，R2(t) 根据尿液和粪便中 47Ca 的每日排泄量计算得出。将数据拟合到不断扩展的可交换钙池模型的修改中。根据血清 47Ca 比放射性曲线和两条保留曲线之间不断增加的差异来估计真皮钙损失。 77 项研究中真皮钙损失的中位数为 1.50 mmol 24 h-1 1.73 m-2（范围 0.13-4.60）。由于示踪剂的重新分布或最终尿液和粪便收集不足，可能会高估真皮钙损失。已经评估了这些错误的可能影响。原发性甲状旁腺功能亢进症患者的真皮钙流失（2.64 mmol；范围 0.80-4.50）高于对照组（1.38 mmol；范围 1.25-2.34）（P 小于 0.02）。
Seventy-seven calcium balance and 47Ca turnover studies were performed in normal volunteers (n = 15) and in patients with osteoporosis (n = 12), primary hyperparathyroidism (n = 8), osteogenesis imperfecta (n = 5), medullary carcinoma of the thyroid (n = 4), thyrotoxicosis (n = 2) and intestinal bypass for obesity (n = 11). After intravenous injection of 20 microCi of 47Ca two retention curves of 47Ca were obtained: R1(t) directly measured on a whole-body counter and R2(t) calculated from the cumulated daily excretions of 47Ca in urine and faeces. The data were fitted to a modification of the continuously expanding exchangeable calcium pool model. Dermal calcium loss was estimated from the serum 47Ca specific radioactivity curve and the constantly increasing difference between the two retention curves. The median dermal calcium loss in 77 studies was 1.50 mmol 24 h-1 1.73 m-2 (range 0.13-4.60). The dermal calcium loss might be overestimated by redistribution of tracer or by eventual insufficient collection of urine and faeces. The possible influences of these errors have been evaluated. Patients with primary hyperparathyroidism had a greater (P less than 0.02) dermal calcium loss (2.64 mmol; range 0.80-4.50) than a control group (1.38 mmol; range 1.25-2.34).