Hwang T I, Hill K, Schneider V, Pak C Y
Department of Internal Medicine, Southwestern Medical School, University of Texas Health Science Center, Dallas 75235.
J Clin Endocrinol Metab. 1988 Jan;66(1):109-12. doi: 10.1210/jcem-66-1-109.
The effect of prolonged bedrest immobilization on urinary risk factors for stone formation and on the propensity for the crystallization of calcium salts was examined in eight normal subjects. During 5 weeks of bedrest, the mean urinary calcium excretion rose during the first week and remained elevated (from 5.68 to approximately 7.50 mmol/day). Mean urinary phosphorus excretion increased by the second week of bedrest and remained elevated (from 2.70 to approximately 30.6 mmol/day). Urinary sodium and uric acid excretion rose slightly, as did urinary magnesium. Urinary pH, oxalate, and citrate changed slightly or not at all. Owing to these biochemical alterations, urinary saturation of calcium phosphate, calcium oxalate, and monosodium urate increased significantly during bedrest, but that of uric acid did not change. The inhibitor activity against the spontaneous nucleation of brushite (CaHPO4.2H2O) and calcium oxalate was not altered significantly by bedrest. Thus, the propensity for the crystallization of stone-forming calcium salts was enhanced by bedrest, suggesting that immobilization may confer increased risk for the formation of calcium-containing renal stones.
在八名正常受试者中，研究了长期卧床制动对结石形成的尿液危险因素以及钙盐结晶倾向的影响。在卧床休息的5周内，尿钙排泄量在第一周上升并持续升高（从5.68 mmol/天增至约7.50 mmol/天）。尿磷排泄量在卧床休息的第二周增加并持续升高（从2.70 mmol/天增至约30.6 mmol/天）。尿钠和尿酸排泄量略有上升，尿镁排泄量也是如此。尿液pH值、草酸盐和柠檬酸盐略有变化或无变化。由于这些生化改变，卧床休息期间磷酸钙、草酸钙和尿酸钠的尿液饱和度显著增加，但尿酸的尿液饱和度未改变。卧床休息对透钙磷石（CaHPO4·2H2O）和草酸钙自发成核的抑制活性没有显著改变。因此，卧床休息增强了形成结石的钙盐结晶倾向，提示制动可能增加含钙肾结石形成的风险。
