INVESTIGATIONS ON THE VITAMIN B₁₂ KINETICS OF DIPHYLLOBOTHRIASIS LATUM BY THE AID OF ⁵⁷Co-VITAMIN B₁₂-HUMAN GASTRIC JUICE AND ⁵⁸Co-VITAMIN B₁₂

Abstract

Tapeworm pernicious anemia is not so rare in the northern Europe. In Japan, no cases of tapeworm pernicious anemia have been reported, though cases of Diphyllobothriasis latum have been increasing recently. 11 cases of Diphyllobothriasis latum were given 0.25μg of ⁵⁷Co-vitamin B₁₂-human gastric juice (0.5μCi), and 0.25μg of ⁵⁸Co-vitamin B₁₂ (0.8μCi) through a Bilbao-Dotter tube inserted into the upper jejunum to know the vitamin B₁₂ kinetics. One hour later, a flushing dose of 1mg non-labelled vitamin B₁₂ was injected intramuscularly. The 24 hours urine was collected (Schilling test) to count ⁵⁷Co and ⁵⁸Co. 48 hours after the start of treatment, the modified method of Damaso de Rivas (Kihara) was performed to expell the worm, and the radioactivity (⁵⁷Co, ⁵⁸Co) of the worm was counted to evaluate the uptake rate of vitamin B₁₂ by the worm. The results of Schilling test were as follows. ⁵⁷Co-vitamin B₁₂-human gastric juice: 14.1±8.1% (x±SD), 5.8-25.3% (range), ⁵⁸Co-vitamin B₁₂: 20.9±10.2% (3.0-31.9%). Abnormal values under 10% were found in only two cases each. The uptake rate of vitamin B₁₂ by the worm varied considerably among 11 cases, e.g. ⁵⁷Co-vitamin B₁₂-human gastric juice: 8.6±8.4% (1.6-24.9%), ⁵⁸Co-vitamine B₁₂: 11.8 ± 15.5% (1.0-50.4%). It is suggested that because these VB₁₂ uptake rates by the tapeworm are so samll, Japanese patients with Diphyllobothriasis latum tend not to develop tapeworm pernicious anemia.