Influence of D-galactosamine on the synthesis of sugar nucleotides and glycoconjugates in rat hepatocytes.

Rat hepatocytes were incubated in the presence of a high concentration of the hepatopathogenic agent D-galactosamine (GalN), and the effect on the cellular concentrations of pyrimidine nucleotides and nucleotide sugars was determined. The UTP pool became depleted. The pools of UMP and CMP in RNA decreased to 72%, indicative for an inhibition of RNA synthesis.

The effect of increasing nucleotide-sugar concentrations on the incorporation of sugars into glycoconjugates in rat hepatocytes.

Treatment of rat hepatocytes with 0.5 mM concentrations of uridine and cytidine results in increased cellular concentrations of UTP, UDP-sugars and CTP, whereas that of CMP-N-acetylneuraminate remained unchanged [Pels Rijcken, Overdijk, Van den Eijnden and Ferwerda (1993) Biochem. J.

Pyrimidine nucleotide metabolism in rat hepatocytes: evidence for compartmentation of nucleotide pools.

Pyrimidine nucleotide metabolism in rat hepatocytes was studied by measurement of the labelling kinetics of the various intermediates after double labelling with [14C]orotic acid and [3H]cytidine, the precursors for the de novo and the salvage pathways respectively. For the uridine nucleotides, differences were found for the 14C/3H ratios in the UDP-sugars, in UMP (of RNA) and in their precursor UTP, suggesting the existence of separated flows of the radioactive precursors through the de novo and the salvage pathways. Higher ratios in the UDP-sugars, which are synthesized in the cytoplasm, and a lower ratio in UMP (of RNA) relative to the 14C/3H ratio in UTP indicated that UTP derived from orotic acid is preferentially used for the cytoplasmic biosynthesis of the UDP-sugars.

Pyrimidine metabolism and sugar nucleotide synthesis in rat liver.

With radioactive precursors, the labelling kinetics of the soluble pyrimidine nucleotides and of RNA were measured in rat liver to determine the contribution of the metabolic flows through synthesis de novo and the salvage pathway. To separate and quantify all pyrimidine nucleotides, an h.p.

[Reconstruction of the urinary bladder following cystectomy].

In 8 male patients a bladder substitute was made of 40 cm detubularized ileum after cystectomy done because of invasive bladder cancer (pT2-3N0M0). The results of this operation as regards bladder functions and morbidity were reasonably good, in accordance with data from the recent literature. Follow-up data over periods longer than 3 years are not yet available.

Glycosylation of three molecular forms of human alpha 1-acid glycoprotein having different interactions with concanavalin A. Variations in the occurrence of di-, tri-, and tetraantennary glycans and the degree of sialylation.

Human alpha 1-acid glycoprotein (AGP) was separated into a non-bound (AGP-A; 46%), a retarded (AGP-B; 39%) and a bound fraction (AGP-C; 15%) using concanavalin A (ConA)-Sepharose chromatography. The apparent molecular masses, as determined by SDS-PAGE, of the three fractions were 43.5, 42.

Treatment of chronic bacterial prostatitis with ciprofloxacin.

Thirty two patients with proven chronic bacterial prostatitis were treated with ciprofloxacin 500 mg twice daily orally for four weeks. The causative organisms, cultured from prostatic fluid were Enterobacteriaceae (19 patients), enterococci (9), staphylococci (4), streptococci (3), non-fermentative Gram-negative rods (2) and anaerobic bacteria (9). Nineteen patients had pure cultures, 13 mixed cultures.

Subcellular localization and tissue distribution of sialic acid-forming enzymes. N-acetylneuraminate-9-phosphate synthase and N-acetylneuraminate 9-phosphatase.

The activities of N-acetylneuraminate 9-phosphate synthase and N-acetylneuraminate 9-phosphatase, the two enzymes involved in the final steps of the biosynthetic pathway of N-acetylneuraminic acid, were measured with the substrates N-acetyl[14C]mannosamine 6-phosphate and N-acetyl[14C]neuraminic acid 9-phosphate respectively. Subcellular localization studies in rat liver indicated that both enzymes are localized in the cytosolic fraction after homogenization in sucrose medium. To test the possibility of misinterpretation due to the hydrolysis of N-acetylneuraminic acid 9-phosphate by non-specific phosphatases, the hydrolysis of various phosphate esters by the cytosolic fraction was tested.

Synthesis of N-acetylneuraminic acid and of CMP-N-acetylneuraminic acid in the rat liver cell.

Adult male rats, under starving and normal conditions, were injected intravenously with N-acetyl[3H]mannosamine and after various time intervals the specific radioactivities of free N-acetylneuraminic acid (NeuAc) and CMP-N-acetylneuraminic acid were determined in the liver. The specific radioactivity of free NeuAc was high even within 20s after injection; the maximum was reached between 7 and 10 min. The specific radioactivity of CMP-NeuAc showed a lag phase of approx.

Subcellular localization and tissue distribution of sialic acid precursor-forming enzymes.

The enzymes UDP-N-acetylglucosamine pyrophosphorylase, UDP-N-acetylglucosamine 2-epimerase, N-acetylmannosamine kinase, N-acetylglucosamine kinase and N-acetylglucosamine 2-epimerase, which are involved in the metabolism of N-acetylneuraminic acid, were studied in rat with regard to their subcellular localization and tissue distribution. The subcellular distribution studies in liver indicated that the enzymes are localized in the soluble cell fraction. In other tissues the comparison of enzyme activities in homogenates with that in high-speed supernatants led to a similar conclusion.

Turnover of free sialic acid, CMP-sialic acid, and bound sialic acid in rat brain.

Adult male rats were injected intraventricularly with N-[3H]acetylmannosamine. After different time intervals the rats were killed and free sialic acid, CMP-sialic acid, lipid- and protein-bound sialic acid were isolated from brain and the specific radioactivities determined. Maximal specific radioactivity was reached after approximately 4 h for CMP-sialic acid, after 10-12 h for free sialic acid and after approximately 42 h for lipid- and protein-bound sialic acid.

Immunological properties of glomerular basement membrane antigens solubilized by elastase digestion.

Glomerular basement membrane (GBM) was solubilized by hog pancreas elastase and fractionated on Bio-Gel P-2. The composition and antigenic properties of elastase-solubilized GBM were compared with those of whole GBM. Elastase-solubilized bovine GBM (ES-BoGBM) and whole bovine GBM (BoGBM) showed similar amino acid and carbohydrate compositions, suggesting that neither the glycoprotein nor the collagen component of the GBM was selectively solubilized.

Preparation and chemical characterisation of calf Tamm-Horsfall glycoprotein.

Tamm-Horsfall glycoprotein preparations were obtained from calf urine by 1.0 M NaCl precipitation followed by 4 M urea/Sepharose 4B chromatography. By using 0.

Experimental study on the mechanism of hyperphosphatasaemia in bile flow obstruction.

Extrahepatic bile flow obstruction is followed by a several-fold increase in alkaline phosphatase activity in the liver. This activity passes into the blood. The increase in the activity of the enzyme in the liver can be prevented by inhibitors of RNA and protein synthesis.

Epithelial basement membrane of bovine renal tubuli. Isolation and analysis of the carbohydrate chains.

The carbohydrate chains present in the tubular basement membrane of bovine kidney were studied. Digestion with collagenase followed with pronase resulted in a complete solubilization of the basement membrane. The different glycopeptides were purified by gel filtration and ion-exchange chromatography.