Miller A, Slingerland D W, Hall C A, Chu R C
Medical Service, VAMC, Boston, Massachusetts 02130, USA.
Am J Hematol. 1998 Sep;59(1):42-5. doi: 10.1002/(sici)1096-8652(199809)59:1<42::aid-ajh8>3.0.co;2-#.
This study was undertaken to determine whether measurements of serum total homocysteine (Hcys) and bound B12 absorption are useful in determining which patients with low- or low-normal levels of serum B12 are B12 deficient. In 40 patients with low or borderline serum levels of B12, food-bound B12 absorptions were determined using a body counter in an iron room, and were related to serum total Hcys levels. Food-bound B12 absorption was decreased in 16 patients and in an additional four, absorption of the free vitamin was also decreased. Homocysteine levels were elevated in four of the 16; in three of the four who had both decreased bound and free B12 absorptions, Hcys was elevated. If elevation of the Hcys level indicates tissue deficiency of B12, the 75% incidence of normal levels of Hcys in these patients with low food-bound B12 absorptions suggests the existence of a cohort of patients who may be at risk to develop, but have not yet developed, B12 deficiency. Only long term follow-up will reveal how many ultimately will become B12 deficient.
本研究旨在确定血清总同型半胱氨酸（Hcys）测量值和结合型维生素B12吸收情况是否有助于判定哪些血清维生素B12水平低或略低于正常水平的患者存在维生素B12缺乏。对40例血清维生素B12水平低或处于临界值的患者，在铁室中使用全身计数器测定食物结合型维生素B12的吸收情况，并将其与血清总Hcys水平相关联。16例患者的食物结合型维生素B12吸收降低，另有4例患者游离维生素的吸收也降低。16例中有4例同型半胱氨酸水平升高；在结合型和游离型维生素B12吸收均降低的4例患者中有3例Hcys升高。如果Hcys水平升高表明组织存在维生素B12缺乏，那么这些食物结合型维生素B12吸收低的患者中Hcys水平正常的发生率为75%，这表明存在一群可能有发生维生素B12缺乏风险但尚未发生缺乏的患者。只有长期随访才能揭示最终会有多少人出现维生素B12缺乏。
