Changes in CD4+CD8-/CD4-CD8+ ratio and humoral immune functions in vitamin B12-deficient rats.

To clarify the role of vitamin B12 in the function of cell-mediated and humoral immune functions, the splenocytes expression of CD4, CD8 and serum C3, IgM, IgG concentrations were examined in vitamin B12-deficient rats, and the effect of the administration of methylcobalamin was also studied. The CD4+CD8-/CD4-CD8+ ratio in splenocytes was significantly higher in vitamin B12-deficient rats than in control rats (p < 0.05). The value in the 48 hours after methylcobalamin administration group, was within the normal range (p < 0.05). From these results, the elevation of the CD4+CD8-/CD4-CD8+ ratio by vitamin B12-deficiency was confirmed in rats. The serum C3, IgM and IgG concentrations were lower in the vitamin B12-deficient group than in the control group. These findings suggest that vitamin B12 plays a role in maintaining the immune function in rats.

Extremely low activity of methionine synthase in vitamin B-12-deficient rats may be related to effects on coenzyme stabilization rather than to changes in coenzyme induction.

Severely vitamin B-12 (B-12)-deficient rats were produced by feeding a B-12-deficient diet. The status of B-12 deficiency was confirmed by an increase in urinary methylmalonate excretion and decreases in liver B-12 concentrations and cobalamin-dependent methionine synthase activity. Rat liver methionine synthase existed almost exclusively as the holoenzyme. In B-12-deficient rats, the level of methionine synthase protein was lower, although the mRNA level was not significantly different from that of control rats. When methylcobalamin, the coenzyme for methionine synthase, was administered to the B-12-deficient rats, growth, liver B-12 concentrations and urinary excretion of methylmalonate were reversed although not always to control (B-12-sufficient) levels in a short period. During this recovery process, methionine synthase activity and its protein level increased, whereas the mRNA level was unaffected. We reported previously that rat apomethionine synthase is very unstable and is stabilized by forming a complex with methylcobalamin. Thus, the extremely low activity of methionine synthase in B-12-deficient rats may be related to effects on "coenzyme stabilization" (stabilization of the enzyme by cobalamin binding) rather than to changes in "coenzyme induction."

[Quantitative cineangiographic evaluation of the valvular regurgitant flow ratio by digital image processing technique (author's transl)].

By application of digital image processing technique to cineangiogram, possibility to calculate the valvular regurgitant flow ratio, especially in patents with aortic regurgitation, was examined. The image processor used was RT6404 made by Amast Computer CO, and the microcomputer to control the image processor was H68TR made by Hitachi Industrial Co. The image of the cineangiogram was photographed by televicamera, and the image processor converted the televi-signal to digitized image. Total volume and concentration of contrast medium in the ventricle was integrated in each systole and diastole. In patients without aortic regurgitation, the volume of contrast medium was not increased in the next diastole after the end of injection. On the contrary, in cases of aortic regurgitation, the volume of contrast medium was increased in the next diastole because of regurgitation. Thus, the regurgitant flow ratio could be calculated from the ejected volume in systole immediately before this diastole and the increased volume caused by the regurgitation.