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When radioactive B12 was added to normal serum, it was bound predominantly to beta globulin. Deficient binding was observed in the serum of five of ten patients with untreated pernicious anemia. Treatment of these patients with B12 restored the beta globulin B12 binding capacity toward normal. In one of the five patients there was virtually no beta globulin binding of added B12 before treatment. This patient exhibited a malabsorptive pattern Schilling test when first seen. Treatment with B12 was attended by an increase of beta globulin binding capacity, and by return of the ability to absorb oral B12 when given with intrinsic factor. It is possible that these two abnormalities are related in that the beta globulin may have an important role in the absorption and transport of B12.

57CoB12 was added to serum in vitro to study its binding by the three known serum B12-binders in patients with vitamin B12 deficiency and in normal controls. Gel filtration through columns of Sephadex G-200 was used to separate the low (beta) and high (alpha1 and beta) molecular weight B12-binding fractions. Electrophoresis on filter paper was used to separate the alpha1- and beta-globulins. The alpha1-globulin fraction in the serum of B12-deficient patients bound more of the added 57CoB12 than did this fraction in normal serum, presumably because this binder of the serum endogenous vitamin B12 is much less saturated in B12-deficiency. However, the total B12 binding capacity of the alpha1-globulin (for endogenous plus added vitamin B12) was lower in B12-deficient than in normal serum. The low molecular weight beta-binder bound more added 57CoB12 in B12-deficient than in normal serum, whereas the high molecular weight beta binder had a much lower B12-binding capacity in deficient than in normal serum. These abnormalities were independent of the cause of the vitamin B12 deficiency and disappeared after successful treatment with vitamin B12.

The binding of vitamin B12 by serum proteins was studied by separating Co57B12-enriched serum by Sephadex gel filtration, column chromatography with DEAE-cellulose, and paper electrophoresis. Each method of separation yielded two discrete B12-binding fractions. However, the analysis of each serum by all three separation technics indicated that one of the fractions was, in each case, bipartite. The "high" molecular weight B12-binding fraction defined by Sephadex gel filtration consisted of transcobalamin I and just part of the transcobalamin II fraction. The remaining portion of transcobalamin II was eluted from Sephadex gel in a "low" molecular weight fraction. Thus, transcobalamin II, equivalent to the β-globulin B12-binder, consisted of both "high" and "low" molecular weight components. This suggests that there are at least three serum proteins that can bind vitamin B12: two β-globulins, together comprising the transcobalamin II fraction and differing in molecular weight; and transcobalamin I.

Endogenous B12 in normal serum has been shown to be associated with α globulins (Pitney, Beard and Van Loon, 1954; Heinrich and Erdmann-Oehlecker, 1956; Mendelsohn, Watkin, Horbett and Fahey, 1958). When B12 has been added to normal serum, however, most or all of the added B12 has been associated with the β- and α2-globulins (Miller, 1958). In the present investigation with radioactive 57cobalt cyanocobalamin (B12*) added to serum, it was possible to define at least two B12-binding proteins (BP), a β-globulin, and an α1 globulin. B12* added to the serum of normal subjects migrated mainly with the β-globulins on electrophoresis, but when added to the serum of B12-deficient subjects, a small fraction of the B12* was also associated with the α2-globulins.

T ills report is concerned with the concentration of reduced glutathione (GSH) in the erythrocytes of patients with megaloblastic anemias. Other investigators have reported that the red cell GSH concentrations are low,’ normal2 or elevated35 in pernicious anemia. The present studies indicate that the level of erythrocyte GSH is increased.

A 35-year-old woman who was hospitalized for hematemesis secondary to alcoholic gastritis incidentally sustained knee trauma and developed a small bloody joint effusion. Routine X-ray stud...

Excerpt Megaloblastic anemia of pregnancy occurs characteristically during the last trimester of pregnancy or during the puerperium (1-3) and in temperate climates is usually secondary to folate de...