Kapadia C R, Bhat P, Jacob E, Baker S J
Gut. 1975 Dec;16(12):988-93. doi: 10.1136/gut.16.12.988.
The intraluminal fate of orally administered radioactive vitamin B12 has been studied in control subjects with normal vitamin B12 absorption and those with vitamin B12 malabsorption due to tropical sprue. In control subjects 1 to 21% of the dose was bound to sedimentable material and 37 to 75% was bound to immunoreactive intrinsic factor. In subjects with vitamin B12 malabsorption due to tropical sprue, the results were identical with the control subjects. Bacteriological studies showed a statistically significant correlation between both the number of flora in the jejunum and the number of bacteroides in both the jejunum and ileum and vitamin B12 malabsorption. In patients with tropical sprue who have normal intrinsic factor secretion, the vitamin B12 absorptive defect is not due to binding of the vitamin to bacteria or to alteration to the intrinsic factor vitamin B12 complex in the intestinal lumen. The lesion appears to be one of the mucosal cell receptors or of the cells themselves, possibly caused by bacterial toxins.
已对维生素B12吸收正常的对照受试者以及因热带口炎性腹泻导致维生素B12吸收不良的受试者口服放射性维生素B12后的管腔内转归进行了研究。在对照受试者中,1%至21%的剂量与可沉淀物质结合,37%至75%与免疫反应性内因子结合。在因热带口炎性腹泻导致维生素B12吸收不良的受试者中,结果与对照受试者相同。细菌学研究表明,空肠内菌群数量以及空肠和回肠内拟杆菌数量与维生素B12吸收不良之间存在统计学上的显著相关性。在具有正常内因子分泌的热带口炎性腹泻患者中,维生素B12吸收缺陷并非由于维生素与细菌结合或肠腔内维生素B12与内因子复合物发生改变所致。病变似乎是黏膜细胞受体或细胞本身的病变,可能由细菌毒素引起。