Neocarzinostatin (NCS) is mutagenic in bacteria, yeast, fungi, and mammalian cells. In cell-free systems, DNA strand breakage induced by NCS requires a reducing agent like 2-mercaptoethanol, unless very high (greater than 100 micrograms/ml) concentrations of NCS are used. In this study, we have investigated the role of the sulfhydryl compound glutathione (GSH), which is usually the most common ...

The aim of this study was to assess the effect of training loads on metabolic response of purine derivatives in highly trained sprinters (10 men, age range 20-29 yr) in a 1-yr cycle, compared with endurance-training mode in triathletes (10 men, age range 21-28 yr). A four-time measurement of respiratory parameters, plasma hypoxanthine (Hx) concentration, and erythrocyte hypoxanthine-guanine pho...

OBJECTIVES To study (a) purine metabolism during treatment with methotrexate (MTX) in patients with rheumatoid arthritis (RA) and (b) the relation of purine metabolism with efficacy and toxicity of MTX treatment. METHODS One hundred and three patients with active RA who started treatment with MTX were included. The initial MTX dosage was 7.5 mg/week and raised to a maximum of 25 mg weekly if ...

The intrachromosomal localization of three X-linked gene loci (PGK, HGPRT and G6PD) has been determined using a somatic cell genetic approach. A human cell line possessing an X/14 translocation was used as one parent in the formation of human/mouse hybrids. The translocation separates the human X into two parts: Xp and t(Xq14q). The data indicate that all three X-linked loci segregate with the ...

Hypoxanthine guanine phosphoribosyltransferases (HGPRTs) catalyze the conversion of 6-oxopurine bases to their respective nucleotides, the phosphoribosyl group being derived from phosphoribosyl pyrophosphate. Recombinant Plasmodium falciparum HGPRT, on purification, has negligible activity, and previous reports have shown that high activities can be achieved upon incubation of recombinant enzym...

The subcellular location of a protein is a critical factor in its physiological function and an important consideration in therapeutic paradigms that target the protein. Because Leishmania donovani cannot synthesize purine nucleotides de novo, they rely predominantly upon therapeutically germane phosphoribosyltransferase (PRT) enzymes, hypoxanthine-guanine PRT (HGPRT), adenine PRT (APRT), and x...

Autoantibody-secreting hybridomas were produced by somatic cell fusion of B lymphocytes from a patient with systemic lupus erythematosus with two different human myeloma lines. Selection of hybrids formed from one of these cell lines was performed by using aminopterine-containing culture medium as this cell line was deficient in hypoxanthine-guanine-phosphoribosyl transferase (HGPRT). The secon...