Serum Vitamin B12 Concentrations of Patients with Megaloblastic Anaemia After Treatment with Vitamin B12, Folic Acid, or Folinic Acid

The urinary excretion and tissue retention of cyanocobalamin by subjects given repeated parenteral doses

“…there is good evidence that urinary excretion is virtually complete within eight hours (Mollin and Ross, 1953). In general the results in this series confirm these findings, although in one patient (case 18) given repeated injections of 1,000 ug.…”

“…An increase in the proportion of injected cyanocobalamin which is excreted in urine with repeated injections has been reported in vitamin B12-deficient patients (Sokoloff, Sanneman, and Beard, 1952;Mollin and Ross, 1953), in normal subjects (Chesterman, Cuthbertson, and Pegler, 1951;Sokoloff et al, 1952;Estrada, Lang, and Chow, 1954), and in one rat (Harte, Chow, and Barrows, 1953). In all but one of these investigations the method adopted was to measure the urinary loss by microbiological assay after a single injection of vitamin B12, to give 'saturating' intramuscular doses ranging from 20 ,ug.…”

“…daily for two weeks (Chesterman et al, 1951) to 1,000 ,ug. daily for seven days (Mollin and Ross, 1953), and then to measure the urinary loss after a further injection of vitamin B12, the dose given being the same as that at the first injection. The conclusion that the proportion excreted increased as the body stores were augmented was based on the finding of a greater amount excreted after the second dose.…”

“…The conclusion that the proportion excreted increased as the body stores were augmented was based on the finding of a greater amount excreted after the second dose. The possibility that the amount excreted after each injection might vary from day to day was considered by Mollin and Ross (1953) but was not thought to constitute a significant variable. From the results shown in Figs.…”

Rapid Estimation of the Serum Vitamin B12 Level by a Microbiological Method

“…Most of the data concerning the serum level of vitamin B12 have been derived from measurement of the growth of the protozoon Euglena gracilis (Hutner et al, 1949;Ross, 1950;Mollin and Ross, 1953). This method is easy to carry out when the necessary apparatus is available, but its advantage to the clinician is lessened by the fact that results are not available within a week.…”