Epstein M, Hoffman D, DeNunzio A G
Miner Electrolyte Metab. 1983 Mar-Apr;9(2):62-8.
It has been proposed that the functional adaptations of surviving nephrons in advancing chronic renal failure (CRF) are not random but characterized by an excretory response which varies inversely with the number of surviving nephrons ('magnification phenomenon'). Because validation of this hypothesis in man is incomplete, we undertook to characterize the excretory response to acute volume expansion in patients with CRF. In normals, water immersion to the neck (NI) results in a redistribution of blood volume with preferential central hypervolemia (CV) in the absence of plasma compositional change. NI was utilized, therefore, to assess the response to acute CV. 13 patients with CRF (GFR = 3-65 ml/min) were studied twice while ingesting a constant diet (60-150 mEq Na/day): during a seated control study (C) and during 4 h of NI. FENa was constant during C. In contrast, during NI, there was a prompt and marked increase in FENa which markedly exceeded that of 29 normal subjects undergoing an identical study. In the CRF group the extent of the augmentation of FENa during immersion varied inversely with GFR (r = -0.54; p less than 0.05). These results provide evidence that the 'magnification phenomenon' subtends renal sodium handling in patients with CRF.
有人提出，在慢性肾衰竭（CRF）进展过程中，存活肾单位的功能适应性并非随机的，而是以一种排泄反应为特征，这种反应与存活肾单位的数量呈反比（“放大现象”）。由于该假说在人体中的验证并不完整，我们着手研究CRF患者对急性容量扩张的排泄反应特征。在正常人中，颈部水浸（NI）会导致血容量重新分布，在血浆成分无变化的情况下，优先出现中心性高血容量（CV）。因此，采用NI来评估对急性CV的反应。13例CRF患者（肾小球滤过率[GFR]=3 - 65ml/分钟）在摄入恒定饮食（60 - 150mEq钠/天）的情况下接受了两次研究：一次是在坐位对照研究（C）期间，另一次是在NI的4小时期间。在C期间，滤过钠排泄分数（FENa）恒定。相比之下，在NI期间，FENa迅速且显著增加，明显超过了29名接受相同研究的正常受试者。在CRF组中，浸入期间FENa增加的程度与GFR呈反比（r = -0.54；p<0.05）。这些结果证明“放大现象”是CRF患者肾脏钠处理的基础。
