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Biomedical subjects

F B Rudolph

Publications and source records attributed to F B Rudolph.

At least 73 records · Page 4Linked to original sources
PubMed1984

Involvement of dietary nucleotides in T lymphocyte function.

The data described above show clearly that absence of a dietary source of preformed purine or pyrimidine bases suppress T lymphocyte function. The heart allograft model assesses the T lymphocyte response to allografts. The SRBC sensitization assay indicates the activity of T effector cells is involved in delayed hypersensitivity. The mitogen assays clearly indicate a dietary effect on in vitro T cell response. The effect of dietary nucleotides on immune function should be of great importance in a number of clinical situations. These include management of organ transplant patients, in recovery from malnutrition, in various chemotherapeutic regimens and in treatment of T cell derived leukemias.

Animals↗
PubMed1984

Functional impairment of T-lymphocytes in mouse radiation chimeras by a nucleotide-free diet.

We examined the effect of a nucleotide-free diet on the immune function of mouse syngeneic bone marrow radiation chimeras. The graft-versus-host disease mortality assay revealed that GVH activity of spleen cells from radiation chimeras fed NFD (RCNFD) was reduced at 6-18 weeks after transplantation as compared with the radiation chimeras fed a control diet (RCCD). When tested 11-18 weeks after transplantation, the proliferative response of RCNFD spleen cells to phytohemagglutinin was significantly reduced at 11 and 13 weeks, the response to pokeweed mitogen (PWM) was significantly reduced at 11, 13, and 15 weeks, and the response to bacterial lipopolysaccharide remained virtually unaffected. At both six and eight weeks after transplantation, RCNFD and RCCD showed comparable numbers of CFUc/femur. RCNFD and RCCD did not differ significantly from each other in body weights or in spleen and bone marrow cellularity at 6-18 weeks after transplantation. These results suggest that dietary nucleotides are important for the normal function of mouse T-lymphocytes.

Animals↗
PubMed1982

Regulation of purine biosynthesis and interconversion in the chick.

In ureotelic species, such as the rat, adaptive changes in metabolic flux and enzyme levels occur in the purine metabolic pathway when cells are rapidly growing. This is observed in both regenerating liver and in malignant tissues. The enzymes P-Rib-PP amidotransferase and IMP dehydrogenase increase in activity in both situations. The level of purine biosynthesis is much higher in uricotelic species, such as the chick, when compared to ureotelic animals. By treating immature roosters with the hormone beta-estradiol, it is possible to induce rapid liver growth, allowing comparison of the regulation of purine biosynthesis and interconversion in high metabolic rate cells with different roles for purine metabolism. The tissue activities of P-Rib-PP amidotransferase, xanthine dehydrogenase, adenylosuccinate synthetase and lyase, AMP deaminase, IMP dehydrogenase, and GMP synthetase did not rise in livers from estradiol-treated chicks, as compared to controls. However, the rate of de novo purine synthesis triples and the intracellular level of P-Rib-PP doubles within 24 h of treatment. The biosynthesis of GMP is elevated at 12 and 24 h, but the levels of soluble nucleotide pools do not change. These data indicate that regulation of the de novo purine pathway in uricotelic species in a high metabolic situation is at the level of substrate availability (P-Rib-PP) and not due to changes in enzyme level or to feedback inhibition.

Animals↗
PubMed1981

Isotope exchange at equilibrium studies with rat kidney gamma-glutamylcysteine synthetase.

The kinetic binding mechanism of rat kidney gamma-glutamylcysteine synthetase has been evaluated by isotope exchange at equilibrium studies. The results are consistent with a Random BC mechanism as suggested previously (Yip, B. P., and Rudolph, F. B. (1976) J. Biol. Chem. 251, 3563-3568). The purification procedure for the enzyme was modified to remove contaminating adenylate kinase prior to isotope exchange studies.

Adenosine Diphosphate↗
PubMed1979

Effect of anthraquinone dyes and evaluation of the kinetic mechanism of yeast phosphoglycerate kinase.

Cibacron Blue 3G-A (CB3G-A, I) was investigated as a ternary complex analogue of lactate dehydrogenase and phosphoglycerate kinase as had been suggested earlier (Stellwagen, E. (1977) Accts. Chem. Res. 10, 92-98). CB3G-A and Procion Brilliant Blue (PBB, II), a structural isomer of the Cibacron dye without the sulfonated benzoyl moiety, were attached covalently to Sepharose CL-6B. The two enzymes were adsorbed to the columns and then eluted by substrates in various combinations. CB3G-A and PBB interact similarly with the two enzymes in spite of the structural differences between the dyes indicating that the specific structure of CB3G-A is not a ternary complex analogue. Inhibition studies of phosphoglycerate kinase by CB3G-A suggest that 2 molecules of dye bind per monomer and are consistent with multiple substrate binding sites. It is suggested that the kinetic mechanism of phosphoglycerate kinase is best described as steady state random.

Anthraquinones↗
PubMed1979

Biosynthesis of the pyrimidine moiety of thiamin in Escherichia coli: incorporation of stable isotope-labeled glycines.

Methods are described for the cleavage, extraction, and subsequent gas chromatographic-mass spectrometric analysis of the pyrimidine moiety of thiamin as 2-methyl-4-amino-5-[(ethylthio)methyl]pyrimidine. The methods are of a general nature and can be applied to any system. Using these methods to evaluate the incorporation of 13C-, 15N-, and 2H-labeled glycines into the pyrimidine moiety of thiamin by Escherichia coli, we established that the nitrogen and carbon atoms of glycine are incorporated as a unit into the pyrimidine. 13C- and 15N-labeled glycines are incorporated at greater than 60% but deuterium from [2-(2)H2]glycine was incorporated at only 18%. A detailed analysis of the mass fragmentation pattern of the pyrimidine derivative has established that the glycine nitrogen atom supplies the N-1 of the pyrimidine and that the C-1 and C-2 of the glycine supplies the C-4 and C-6 of the pyrimidine, respectively. This evidence is consistent with the substitution of a C2 unit between the C-5 and C-4 of the 4-aminoimidazole ribonucleotide precursor during the biosynthesis of the pyrimidine moiety of thiamin in E. coli.

Carbon Isotopes↗
PubMed1979

Purine biosynthesis in Helix aspersa: metabolic fate of labelled precursors.

1. The hepatopancreas of terrestial snails actively synthesizes purines from labelled formic acid. 2. The guanine nucleotides are initially labelled to the highest specific activity followed by adenine and hypoxanthine. 3. The labelling patterns suggest that uric acid synthesis is the primary catabolic process for nitrogen excretion while guanine excretion is due to an inability to reutilize the base.

Animals↗