DIURNAL VARIATION OF URINARY PH

这个子项目是许多利用 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 在尿酸结石患者中发现的最不变的特征是尿pH值异常低（<5.5）。间歇性地，这样的值在非结石形成者中被检测到，然而，在昼夜节律模式中发生的pH的周期性变化似乎保护正常受试者免于肾结石。 初步研究表明，尿酸结石形成者保持持续的低尿液pH值，没有昼夜波动，并且由于这种环境易于尿酸沉淀。 假设： 1)正常人尿液pH值、血浆和尿液酸碱参数存在昼夜变化。 2)部分昼夜变化是由于胃分泌。 3)这种昼夜节律在尿酸结石形成者中改变。 将通过实现以下目标来检验假设： 1)明确正常人尿pH和血浆/尿酸碱参数状态是否存在周期性变化，尿酸结石患者是否存在差异。 2)探讨昼夜变化是否是由于胃酸分泌，从而通过质子泵抑制剂的管理，无论是在正常受试者和尿酸结石形成者修改。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The most invariant feature found among uric acid stone formers is an abnormally low urinary pH (<5.5). Intermittently, such values are detected in non stone formers, however, cyclical variation in pH that occur in a circadian pattern appear to protect normal subjects from nephrolithiasis. Preliminary studies suggest that uric acid stone formers maintain a persistently low urine pH, without diurnal fluctuations, and because of this environment are predisposed to uric acid precipitation. Hypotheses: 1) There is a circadian variation in urine pH, and plasma and urinary acid-base parameters in normal subjects. 2) Part of the diurnal variation is due to gastric secretion. 3) This circadian profile is altered in uric acid stone formers. The hypotheses will be tested by achieving the following objectives: 1) define whether cyclic variation in urine pH and plasma/urine acid base parameters status exists in normal subjects and whether it differs in uric acid stone formers. 2) explore if the diurnal variation is due to gastric acid secretion and thus modified by the administration of a proton pump inhibitor, both in normal subjects and uric acid stone formers.