Remission of Diabetes Mellitus during Pregnancy

Two cases are reported in which a remission of diabetes was sustained throughout pregnancy. This seemed to be due in part to improved β-cell function consequent on restoration of normoglycaemia before pregnancy, and in part to an increase in insulin sensitivity during pregnancy, which in the first case disappeared very rapidly after delivery.     

Regulation of collagen synthesis by ascorbic acid. Ascorbic acid increases type I procollagen mRNA

Ascorbic acid specifically stimulates collagen production in cultured human skin fibroblasts, an effect that appears to be independent of its cofactor role in prolyl and lysyl hydroxylation. In order to investigate the level of regulation of ascorbic acid on collagen synthesis, we have translated mRNA in a cell-free system derived from rabbit reticulocytes. Total RNA was prepared from normal human skin fibroblasts and similar fibroblasts which had been exposed to 100 uM ascorbic acid for four days. Ascorbic acid treatment resulted in a twofold stimulation of procollagen mRNA whereas non-collagenous mRNA was unchanged. These results reveal that ascorbic acid has a preferential stimulating effect on type I procollagen mRNA.     

Transfer of small DNA fragments from polyacrylamide gels to diazobenzyloxymethyl-paper and detection by hybridization with DNA probes.

A method for transferring small DNA fragments from composite polyacrylamide-agarose gels to diazobenzyloxymethyl (DBM)-paper is described. DNA fragments are separated by electrophoresis in polyacrylamide-agarose gels crosslinked with N,N′-diallyltartardiamide instead of N,N′-methylenebis-acrylamide. The crosslinks are cleaved by treating the gel with periodic acid after electrophoresis and the DNA is denatured with alkali. After neutralization, the single stranded DNA fragments are transferred to DBM-paper and detected by hybridization with labeled DNA probes. The procedure has been used to transfer and visualize unlabeled SV40 DNA fragments in the size range 28 to 1790 base pairs.     

Binding of N5,N10-methylene tetrahydrofolate and the inhibition of thymidylate synthesis by a folate-binding protein

A mixture of two ionic forms of a folate-binding protein purified from chronic myelogenous leukemia cells reversibly binds N⁵, N¹⁰-methylene tetrahydrofolate and prevents the coupling of this cofactor to thymidylate synthetase in a terniary complex with fluorodeoxyuridylate. The binding protein also inhibits the enzymic synthesis of thymidine monophosphate by preventing the methylation of deoxyuridylate. These findings suggest that one function of the folate-binding protein may be to regulate the intracellular concentration of free folate cofactors and, thereby, modulate their functional activity.