Summary. The vitamin B12 content of 17 tissues in 28 adults and 17 foetuses was measured by a Euglena gracilis bioassay. The former were taken after sudden deaths, many accidental, and the latter after therapeutic abortions for mild psychiatric reasons. In the adult, the liver had the highest level of vitamin B12 followed by the kidney, adrenal, pancreas and heart. The tissues of greatest vitamin B12 concentration in the foetus were the liver, adrenal, kidney and lung. Foetal spleen, lung and colon were significantly higher than their adult counterparts, while foetal liver, kidney, heart and brain were significantly lower in comparison with the adult. Differences in vitamin B12 levels may reflect adult and foetal differences in circulation, metabolic maturity or plasma vitamin B12 transport.

No abstract

No abstract

Levels of plasma folate, erythrocyte folate and serum vitamin B12 were measured in 106 essentially healthy persons grouped both as to race and economic--educational status. Whereas the mean values of the three assays did not differ significantly among groups, values of plasma folate below the usual limits of normal were more prevalent in the migrant worker and urban clinic groups. Persons with low plasma folate levels did not have symptomatic deficiency as evaluated by hematocrit, peripheral blood smears and erythrocyte folate levels. The interpretation of the plasma folate requires reference values from a healthy population selected to be comparable to the study group. The diagnosis of deficiency, or at least the degree of deficiency, requires clinical and laboratory evaluations beyond the plasma folate.