Pigment biosynthesis in the cyanobacterium, Anacystis nidulans, was examined in the presence of gabaculine (5-amino-1,3-cyclohexadienyl-carboxylic acid). At 20 micromolar, this inhibitor blocked the biosynthesis of both chlorophyll and phycocyanin. Analogs of gabaculine were not effective as inhibitors of chlorophyll or phycocyanin biosynthesis. Iron- and phosphate-deficient cultures were 2- to...

We have investigated the possible toxicity of nitrous oxide on vitamin B12 and its sequelae upon folic acid metabolism using the urine formiminoglutamic acid excretion test, an index of the functional state of folate metabolism. Ten control subjects not exposed to nitrous oxide and five patients receiving limb surgery under local anaesthesia excreted normal amounts of formiminoglutamic acid in ...

Metabolic acidosis is associated with poor outcomes in CKD. Because impaired renal ammonium excretion is important in the pathogenesis of acidosis, urine ammonium excretion might be a better and perhaps earlier acid-base indicator of risk than serum bicarbonate, particularly in patients without acidosis. We evaluated the association between baseline ammonium excretion and clinical outcomes in A...

OBJECTIVE Previous studies have demonstrated that the lower renal excretion of urates in patients with hyperuricaemia is inversely related to plasma very low-density lipoprotein (VLDL) levels, and the different genotypes of the apolipoprotein E gene are related to the plasma levels of lipids. The aim of this study was to determine the prevalence of apolipoprotein E in hyperuricaemic patients an...

The 24-hr urinary excretion of certain metabolites of tryptophan was measured in 22 patients with Hodgkin's disease and 18 patients with lymphosarcoma, following the P.O. administration of 2 g L-tryptophan. An assay of hepatic tryptophan pyrrolase activity was done on 15 patients with Hodgkin's disease and 15 patients with lymphosarcoma, and an assay of hepatic ky'hureninase was done on 11 and ...

Background. Skeletal fragility is a complication of phenylketonuria (PKU). A diet containing amino acids compared with glycomacropeptide reduces bone size and strength in mice. Objective. We tested the hypothesis that amino acid medical foods (AA-MF) provide a high dietary acid load, subsequently increasing urinary excretion of renal net acid, calcium, and magnesium, compared to glycomacropepti...

It is well known that the tissues of albino rats, without an external source of vitamin C, contain appreciable concentrations of ascorbic acid as measured by staining techniques, chemical titration, and biological assay. The relative distribution and absolute concentrations appear to be fairly constant and regulated by synthesis in vivo, under most conditions of dietary regimen, but extreme var...

Gout is a common rheumatic disease in humans which is characterized by elevation in serum uric acid levels, and deposition of uric acid crystals in the joint. Hyperuricaemia is the primary risk factor for the development of gout and primates have uniquely high levels of serum uric acid due to missense mutations in the uricase gene. Levels of serum uric acid are known to be highly heritable, and...

It is well known that the tissues of albino rats, without an external source of vitamin C, contain appreciable concentrations of ascorbic acid as measured by staining techniques, chemical titration, and biological assay. The relative distribution and absolute concentrations appear to be fairly constant and regulated by synthesis in vivo, under most conditions of dietary regimen, but extreme var...

The effects of aniso-osmotically and amino-acid-induced cell-volume changes on bile flow and biliary taurocholate excretion were studied in isolated perfused rat liver. With taurocholate (100 microM) in the influent perfusate, hypo-osmotic exposure (225 mosmol/l) increased taurocholate excretion into bile and bile flow by 42 and 27% respectively, whereas inhibition by 32 and 47% respectively wa...