allopurinol and Pheochromocytoma

Acute tumor lysis syndrome (ATLS), which occurs spontaneously, without cytotoxic therapy, is a rare condition. Spontaneous TLS (STLS) has been seen most commonly in lymphoma and leukemia. We report a series of 3 cases of STLS in patients with solid tumors who were hospitalized in our department during a 9-month period and suggest that STLS is probably more frequent than previously thought.

Topics: Adrenal Gland Neoplasms; Aged; Aged, 80 and over; Allopurinol; Bone Neoplasms; Colonic Neoplasms; Female; Fluid Therapy; Humans; Hydrogen-Ion Concentration; Liver Neoplasms; Male; Necrosis; Pheochromocytoma; Tomography, X-Ray Computed; Tumor Lysis Syndrome; Urine

Rat pheochromocytoma PC 12 cells are susceptible to the oxidative toxicity caused by H2O2, nitrofurantoin, dopamine, and xanthine/xanthine oxidase reaction. The cytotoxicities of these agents are greatly reduced by the simultaneous presence of 0.1 mM tetrahydrobiopterin (BH4), 3 units/ml horseradish peroxidase, 0.2 mM NADH, and 0.1 units/ml sheep liver dihydropteridine reductase (DHPR). Individually, BH4, NADH and DHPR have no protection against H2O2 toxicity in PC 12 cells. Peroxidase alone offers 58% of protection if cells are incubated in the medium but only 3% in Dulbecco's phosphate buffered saline. The efficiency of the BH4-mediated antioxidation system in PC 12 cells is equal to or better than ascorbic acid and catalase, depending on the source of the reactive O2 species (ROS). The reactions responsible for the BH4-antioxidation system may consist of the non-enzymatic and the peroxidase-catalyzed reduction of H2O2 to H2O by BH4 and the regeneration of BH4 by DHPR using NADH as the cofactor. The components of this defence mechanism against ROS are all normal cellular constituents and are ubiquitous in nature. This DHPR-catalyzed redox cycling of BH4 may constitute an as yet little-known antioxidation system in mammalian cells.

Topics: Adrenal Gland Neoplasms; Animals; Antioxidants; Biopterins; Dihydropteridine Reductase; NAD; Nitrofurantoin; Peroxidases; Pheochromocytoma; Rats; Tumor Cells, Cultured; Xanthine Oxidase

A now 45-year-old man with marked chronic tophous gout and recurrent nephrolithiasis has been followed for 12 years. First gouty symptoms appeared at age 18. Uric-acid reducing treatment freed the patient of symptoms, and bony and soft-tissue tophi in part regressed. The early onset and high urinary uric-acid excretion indicated increased uric-acid production. Decreased activity of the enzyme hypo-xanthine-guanine-phosphoribosyl transferase was demonstrated to be the cause of the hyperuricaemia, which led to an excessive purine synthesis. An almost complete loss of activity of this enzyme is the basis of the Lesch-Nyhan syndrome. In the described patient all of the neurological and behavioural disorders of the Lesch-Nyhan syndrome were absent. A pheochromocytoma was found to be the cause of malignant hypertension, which had been present for many years.

Topics: Adrenal Gland Neoplasms; Allopurinol; Gout; Humans; Hypertension, Malignant; Hypoxanthine Phosphoribosyltransferase; Kidney Calculi; Male; Middle Aged; Pheochromocytoma; Uric Acid

Topics: Blood; Blood Group Antigens; Carbon Isotopes; Catecholamines; Electrophoresis; Humans; Jejunum; Kidney; Liver; Metabolism; Pheochromocytoma; Purine-Pyrimidine Metabolism, Inborn Errors; Purines; Uric Acid; Urine; Xanthine Oxidase; Xanthines