Beukeveld G J, Bijleveld C M, Kuipers F, Kreeftenberg H G, Huizenga J R, te Velde K, Wolthers B G
Central Laboratory for Clinical Chemistry, University Hospital Groningen, The Netherlands.
Eur J Clin Chem Clin Biochem. 1995 Jul;33(7):453-62.
The Enterotest string test is an easy and non-invasive method for sampling duodenal fluid, which has been successfully used for the analysis of duodenal microflora, as well as biliary bile acid and lipid composition. The method was evaluated for determination of porphyrins in duodenal bile in normal subjects and subjects with porphyria, following cholecystokinin induced gall bladder contraction; it is known that analysis of biliary porphyrins is more discriminatory for the diagnosis of asymptomatic porphyria than their analysis in faeces or urine. Moreover, serial analysis of bile from patients with erythropoietic protoporphyria may help in establishing their ability to secrete protoporphyrin in bile and to assess effects of treatment. The binding of various porphyrins to Enterotest strings was investigated by incubating pieces of the string in different human bile samples with low to very high porphyrin concentrations, followed by HPLC analysis of porphyrins both in the native bile and in extracts obtained from the strings. No differences between porphyrin composition in native bile and extracts were observed. Duodenal fluid obtained by means of the Enterotest from volunteers not receiving cholecystokinin showed large variations in porphyrin patterns not resembling those of native bile. Mesoporphyrin, a secondary porphyrin derived from protoporphyrin by bacteria, was often detectable. These data indicate that the duodenal content without cholecystokinin injection does not reflect biliary porphyrin composition. The presence of mesoporphyrin in the whole intestinal tract, but not in serum and bile, suggests that there is no enterohepatic circulation of secondary porphyrins. There was close agreement between the porphyrin ratios found with the standard duodenal intubation technique and the Enterotest, performed simultaneously in one healthy volunteer after induction of gall bladder contraction by cholecystokinin. From these experiments, it was concluded that fluid adsorbed to the Enterotest string after gall-bladder contraction can be used to determine biliary porphyrin composition. Since duodenal bile is diluted gall bladder bile, variable porphyrin concentrations were found when applying the Enterotest in combination with cholecystokinin in the same subject on successive days. However, porphyrin ratios, such as the protoporphyrin to coproporphyrin I ratio, were relatively constant. In subjects with symptomatic variegate porphyria, the Enterotest showed highly aberrant porphyrin patterns, with increased protoporphyrin to coproporphyrin I ratios and, in addition, the presence of some unknown porphyrins. A deviating biliary protoporphyrin/coproporphyrin I ratio in one patient appeared to be a useful diagnostic index for the presence of latent variegate porphyria (or variegate porphyria in remission).(ABSTRACT TRUNCATED AT 400 WORDS)
肠内试验线试验是一种采集十二指肠液的简便、非侵入性方法，已成功用于分析十二指肠微生物群以及胆汁胆汁酸和脂质成分。该方法用于评估正常受试者和卟啉症患者在胆囊收缩素诱导胆囊收缩后十二指肠胆汁中卟啉的含量；已知胆汁卟啉分析对无症状卟啉症的诊断比粪便或尿液中的分析更具鉴别力。此外，对红细胞生成性原卟啉症患者胆汁的系列分析可能有助于确定他们在胆汁中分泌原卟啉的能力并评估治疗效果。通过将线的片段在不同卟啉浓度从低到非常高的人胆汁样本中孵育，然后对天然胆汁和从线中获得的提取物中的卟啉进行高效液相色谱分析，研究了各种卟啉与肠内试验线的结合。未观察到天然胆汁和提取物中卟啉组成的差异。通过肠内试验从未接受胆囊收缩素的志愿者获得的十二指肠液显示卟啉模式存在很大差异，与天然胆汁的模式不同。中卟啉是一种由细菌从原卟啉衍生而来的次级卟啉，经常可以检测到。这些数据表明，未注射胆囊收缩素时的十二指肠内容物不能反映胆汁卟啉组成。次级卟啉在整个肠道中存在，但不在血清和胆汁中，这表明次级卟啉不存在肠肝循环。在一名健康志愿者中，通过胆囊收缩素诱导胆囊收缩后，同时使用标准十二指肠插管技术和肠内试验发现的卟啉比率之间有密切一致性。从这些实验得出结论，胆囊收缩后吸附在肠内试验线上的液体可用于测定胆汁卟啉组成。由于十二指肠胆汁是稀释的胆囊胆汁，在同一受试者连续几天将肠内试验与胆囊收缩素联合应用时，发现卟啉浓度存在变化。然而，卟啉比率，如原卟啉与粪卟啉I比率，相对恒定。在有症状的杂合性卟啉症患者中，肠内试验显示卟啉模式高度异常，原卟啉与粪卟啉I比率增加，此外还存在一些未知卟啉。一名患者胆汁中原卟啉/粪卟啉I比率的偏差似乎是潜伏性杂合性卟啉症（或缓解期杂合性卟啉症）存在的有用诊断指标。（摘要截短于400字）
