Altered purine and pyrimidine metabolism in erythrocytes with purine nucleoside phosphorylase deficiency

Purine and pyrimidine metabolism was compared in erythrocytes from three patients from two families with purine nucleoside phosphorylase deficiency and T-cell immunodeficiency, one heterozygote subject for this enzyme deficiency, one patient with a complete deficiency of hypoxanthine-guanine phosphoribosyltransferase, and two normal subjects. The erythrocytes from the heterozygote subject were indistinguishable from the normal erythrocytes. The purine nucleoside phosphorylase deficient erythrocytes had a block in the conversion of inosine to hypoxanthine. The erythrocytes with 0.07% of normal purine nucleoside phosphorylase activity resembled erythrocytes with hypoxanthine-guanine phosphoribosyltransferase deficiency by having an elevated intracellular concentration of PP-ribose-P, increased synthesis of PP-ribose-P, and an elevated rate of carbon dioxide release from orotic acid during its conversion to UMP. Two hypotheses to account for the associated immunodeficiency—that the enzyme deficiency leads to a block of PP-ribose-P synthesis or inhibition of pyrimidine synthesis—could not be supported by observations in erythrocytes from both enzyme-deficient families.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44134/1/10528_2004_Article_BF00484238.pd

Correspondentie David van Dantzig-Gerrit Mannoury : historische notitie SEN

Correspondence David van Dantzig--Gerrit Mannoury October 23rd 1917, after the second lecture in a course on analytical geometry David van Dantzig, student of chemistry, wrote a long letter to the professor of mathematics Gerrit Mannoury. It proved the starting point of a life-long symbiosis of pupil and master in mathematics, metamathematics and significs. Significs was the novel theory of intersubjective understanding. Gerrit Mannoury, 1867-1956, self-educated mathematician and communist was the central figure in the signific circle, a Dutch counterpart of the Vienna circle. David van Dantzig, 1900-1959, grew to be a successful mathematician. In the late 1930's he turned to applications and mathematical modelling. After the war Van Dantzig cofounded the CWI. He placed mathematical statistics on the mathematical agenda in the Netherlands. This historical note offers an inventory of their correspondence