Microspectrophotometric determination of desoxyribosenucleic acid in megaloblasts of pernicious anemia.

By EDWARD II. REISNER JR., M.D. AND ROY KORSON, M.D.* W ITt! THE ISOLATION of vitamin B12’ an(l its (lemonstration as the ad-ti\’e anti-pci-md-ions anemia substance of liver,2 attention ‘as focused on some of its biochemical properties. It was shown that in the growth redluirements of various micro-organisms, vitamin B12 could be replaced by various desoxyribosides,4 5 from which evidence its role in desoxyriboside and nucleic ack! synthesis could be inferredl. Pteroylglutamic acid (PGA) has been shown to be replaceable by thymine in the growth of certain bacteria6 and Shive7 has shown that both B12 and PGA are intimately involved in the synthesis of both amino acids and purine and pyrimid!ine bases. In man, the test-tube relationships Of PGA and thvmine have been reproduced clinically5 and thymidine in amounts UP td) 150 mg. has been showii to produce slight reticulocyte activity but has not been able to effect remission in pernicious anemia.#{176} From these studies it seemed possible that the deficiency state in pernicious anemia might lead to a (lecrea.se in the amount of diesoxyrihosenucleic acid in the megaloblast nucleus, andl that the paler staining properties of such nuclei might be attributable to a lack of that substance. The mici-ospectrophotometric technic originated by Caspersson’#{176} providles a valuable aid in the dfuantitative estimation of cellular constituents of the magflitli(les found in indlivid!ual cells. ThorelP’ #{149} ‘ has used this technic to determine the amounts of ribosenucleic acid! in maturing blood! cells by measuring their