Centre of Biomedical Magnetic Resonance, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, India.
J Gastrointestin Liver Dis. 2009 Mar;18(1):27-32.
Evaluation of small intestinal permeability (SIP) is based on the estimation of the urinary excretion ratio of a large and a small molecule (lactulose and mannitol, L/M) after oral administration. We evaluated SIP using 1H-NMR spectroscopy.
In-vitro experiments on known concentration of mannitol and lactulose solutions were performed to measure accuracy and precession of quantification using 1H-NMR spectroscopy. Eighteen patients with malabsorption syndrome (MAS) and 28 healthy subjects (HS) underwent SIP evaluation using L/M excretion ratio over 6-h after oral administration of 15 mL (10g) lactulose and 5 g mannitol using 1H-NMR spectroscopy and trimethyl silyl propionic acid as external reference and for quantification.
Median errors of estimation of mannitol and lactulose were 5% (range 1.2 to 5) and 1.3% (range 0.2 to 1.3), respectively in-vitro. Patients with MAS excreted higher quantity of lactulose in urine than HS (median 0.33 mmol vs 0.12, 0 to .676 mmol, p<0.008). There was a trend towards lower urinary excretion of mannitol in patients with MAS than HS (median 3.58, range 0.61 to 15.77 mmol vs. 3.82, 1.34 to 16.42 mmol, p = ns). L/M ratio was higher among patients with MAS as compared to HS (median 0.1172 vs 0.045, p< 0.002). A cut-off value of L/M excretion ratio by receiver-operating characteristic (ROC) curve of 0.049 had a sensitivity and specificity of 72% and 61%, respectively; a cut-off value of 0.078 had a specificity of 90% but low sensitivity (67%). Area under ROC curve was 0.77.
1H-NMR spectroscopy is an analytical tool for assessment of SIP with reasonable sensitivity and specificity.
小肠通透性（SIP）的评估基于口服后大、小分子（乳果糖和甘露醇，L/M）尿排泄率的估计。我们使用 1H-NMR 光谱法评估 SIP。
对已知浓度的甘露醇和乳果糖溶液进行了体外实验，以测量使用 1H-NMR 光谱法进行定量的准确性和精度。18 例吸收不良综合征（MAS）患者和 28 例健康受试者（HS）在口服 15mL（10g）乳果糖和 5g 甘露醇后 6 小时内，使用 1H-NMR 光谱法、三甲基硅丙酸作为外参和定量，评估 L/M 排泄率。
体外实验中，甘露醇和乳果糖的估计中位数误差分别为 5%（范围 1.2 至 5）和 1.3%（范围 0.2 至 1.3）。MAS 患者尿液中乳果糖排泄量高于 HS（中位数 0.33mmol 对 0.12，0 至 0.676mmol，p<0.008）。MAS 患者的甘露醇尿排泄量呈下降趋势低于 HS（中位数 3.58，范围 0.61 至 15.77mmol 对 3.82，1.34 至 16.42mmol，p=ns）。与 HS 相比，MAS 患者的 L/M 比值较高（中位数 0.1172 对 0.045，p<0.002）。ROC 曲线的 L/M 排泄率截断值为 0.049，其敏感性和特异性分别为 72%和 61%；截断值为 0.078 时特异性为 90%，但敏感性较低（67%）。ROC 曲线下面积为 0.77。
1H-NMR 光谱法是一种具有合理敏感性和特异性的 SIP 评估分析工具。
