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Pharmacokinetic studies of N-butyric acid mono- and polyesters derived from monosaccharides.

The pharmacokinetics of seven butyric esters derived from monosaccharides were studied after iv administration of a bolus dose to rabbits. Results obtained showed that a constant plasma level of butyric acid is maintained due to the slow disappearance of butyric acid esters from the plasma in contrast to the case of salts, such as arginine butyrate, which are rapidly cleared. The maintenance of these covalent compounds in the body can increase concentrations of n-butyric acid in the tumor area for more efficient chemotherapy. These results seem to be directly related to the in vitro anticellular activity of butyric esters and the prolonged therapeutic protection in tumor-bearing animals.

Animals↗

A fluorometric determination method for D,L configurations of per-O-methylated monosaccharides by anomeric 2-methyl-2-beta-naphthyl-1,3-benzodioxole 4-carboxylation and high-performance liquid chromatography.

Per-O-methylated pentopyranoses and hexopyranoses were converted to their glycosyl chlorides and coupled with cesium salt of fluorescent chiral derivatization reagent, (+)-2-methyl-2-beta-naphthyl-1,3-benzodioxole-4-carboxylic acid [(+)-MND carboxylic acid], to afford their 1-O-(+)-MNB carboxylates. The D,L enantiomers were separated by normal-phase HPLC and determined at the picomolar level, and this methodology could be extended to the highly sensitive simultaneous determination of per-O-methylated monosaccharides.

Carboxylic Acids↗

Simultaneous determination of monosaccharides in glycoproteins by capillary electrophoresis.

A rapid, easy, and reproducible capillary electrophoretic method for the simultaneous determination of acidic, neutral, and amino sugars and sugar alcohols was developed. Underivatized mannuronic acid, glucuronic acid, galacturonic acid, N-glycolylneuraminic acid, N-acetylneuraminic acid, glucosamine, galactosamine, mannose, xylose, glucose, galactose, fucose, ribose, mannitol, sorbitol, xylitol, and inositol were simultaneously determined with indirect UV detection using 2,6-pyridinedicarboxylic acid as a background electrolyte. A highly alkaline pH condition was used in order to charge carbohydrates negatively and to promote migration toward the anode. Electroosmotic flow was reversed to the direction of the anode by adding cetyltrimethylammonium bromide to the electrolyte. The separation of the carbohydrates was investigated by optimizing the operating pH value and satisfactory resolution was obtained at pH 12.1. The relative standard deviations of the method for carbohydrates were between 0.02 and 0.33% for migration times and were greater than 2.7% for peak areas (n = 6). The minimum detectable level ranged from 23 to 71 microM with a 6-nl injection at a signal-to-noise ratio of 3. This method was applied to the composition analysis of monosaccharides in glycoprotein. After acid hydrolysis of fetuin under each optimum condition, sialo, neutral, and amino sugars were quantified under the same electrophoretic condition.

Animals↗

Characterization of multicomponent monosaccharide solutions using an enzyme-based sensor array.

We report the development of a sensor for rapidly and simultaneously measuring multiple sugars in aqueous samples. In this strategy, enzyme-based assays are localized within an array of individually addressable sites on a micromachined silicon chip. Microspheres derivatized with monosaccharide-specific dehydrogenases are distributed to pyramidal cavities anisotropically etched in a wafer of silicon (100) and are exposed to sample solution that is forced through the cavities by a liquid chromatography pumping system. Production of fluorescent reporter molecules is monitored under stopped-flow conditions when localized dehydrogenase enzyme systems are exposed to their target sugars. We demonstrate the capability of this analysis strategy to quantify beta-D-glucose and beta-D-galactose at low micromolar to millimolar levels, with no detectable cross-talk between assay sites. Analysis is achieved either through fluorescence detection of an initial dehydrogenase product (NADH, NADPH) or by production of a secondary fluorescent product created by hydride transfer from the reduced nicotinamide cofactor to a fluorogenic reagent. The array format of this sensor provides capabilities for redundant analysis of sugars and for monitoring levels of other solution components known to affect the activity of enzymes. The use of this strategy to normalize raw fluorescence signals is demonstrated by the determination of glucose and pH on a single chip. Alternatively, uncertainties in the activity of an immobilized enzyme can be accounted for using standard additions, an approach used here in the determination of serum glucose.

Biosensing Techniques↗

Butyric acid and its monosaccharide ester induce apoptosis in the HL-60 cell line.

Butyric acid is a potent cell growth inhibitor and differentiation inducer (1-4). However, the short plasma half-life of this fatty acid limits its potential therapeutic use (5,6). The recent synthesis of several monosaccharide esters of butyric sodium salt (BuONa) with a prolonged plasma half-life and similar biological properties as the sodium salt opens new perspectives (7-12). We report here that the human myeloid HL-60 cell line can be induced to apoptosis when cultured with one of these esters, monoacetone glucose 3-butyrate (MAG = 3but) or BuONa. Cytospin slide preparations and flow cytometric studies showed that HL-60 cells treated with 1 mM MAG = 3but or BuONa exhibited a reduction in cell volume and condensation of nuclear structure characteristic of apoptosis, associated with monocytic differentiation. Time course studies demonstrated that DNA fragmentation, as determined by agarose gel electrophoresis, was detected 4 hours after incubation with the drugs, while morphologic signs appeared at day 3. Apoptotic cells increased with culture time and reached a maximum at day 6 of 20 +/- 5% with BuONa, 25 +/- 5% with MAG = 3but, and only 5 +/- 2% in controls. These findings suggest that these drugs may exert their actions, at least in part, through induction of apoptosis.

Antineoplastic Agents↗

The cell surface of a restrictive fenestrated endothelium. I. Distribution of lectin-receptor monosaccharides on the choriocapillaris.

The choriocapillaris is one example of a capillary bed lined by a fenestrated endothelium that is restrictive to exogenous tracers and endogenous plasma proteins. In this study we have examined the distribution of cell-surface monosaccharides utilizing biotinylated lectin-avidin ferritin cytochemistry. Receptors for wheat germ agglutinin were localized to the plasmalemma and diaphragms of some fenestrae, vesicles, and channels at the luminal endothelial front in amounts greater than seen for the other lectins employed. The absence of labeling following inhibition with N-acetylglucosamine and after tissue digestion with N-acetylhexosaminidase, but not after neuraminidase indicated that this lectin marked N-acetylglucosamine residues and not sialic acid. Wheat germ agglutinin receptors were not affected by pronase E or trypsin digestion, but were partially removed by proteinase K. The latter also removed many fenestral diaphragms. Wheat germ agglutinin receptors were cleaved with endoglycosidase D. The combined results indicate that the wheat germ agglutinin receptor is of the low-mannose type and part of a protein with hydrophobic properties. Receptors for concanavalin A (mannose) and Ricinus communis agglutinin (galactose) were also localized to the plasmalemma and endothelial diaphragms. The examination of sections at different tilt angles revealed that these lectins bound to the endothelium in a non-random distribution, encircling diaphragms of fenestrae and channels. Soybean agglutinin (N-acetylgalactosamine) marked endothelial structures sparsely. Following digestion with pronase E or trypsin, receptor sugars for the latter three lectins were completely removed, indicating their presence on protease susceptible glycoproteins. These findings demonstrate that the endothelium of the choriocapillaris bears carbohydrate moieties that are different than those described for permeable fenestrated endothelia.

Animals↗

Analysis of coenzyme Q systems, monosaccharide patterns of purified cell walls, and RAPD-PCR patterns in the genus Kluyveromyces.

Analysis of the coenzyme Q system and the monosaccharide pattern of purified cell walls were used for species characterization in the genus Kluyveromyces. All the type strains of the genus possess coenzyme Q-6 and the mannose-glucose ('Saccharomyces type') cell wall sugar pattern. With the help of Random Amplified Polymorphic DNA-Polymerase Chain Reaction analysis 17 species were separated: K. aestuarii, K. africanus, K. Bacillisporus, K. blattae, K. delphensis, K. dobzhanski, K. lactis (anamorph Candida sphaerica), K. lodderae, K. marxianus (syn. K. fragilis, K. bulgaricus, K. cicerisporus, anamorphs Candida macedoniensis, C. pseudotropicalis, C. kefyr), K. phaffii, K. piceae, K. polysporus, K. sinensis, K. thermotolerans (syn. K. veronae, anamorph Candida dattila), K. waltii, K. wickerhamii, K. yarrowii (anamorph Candida tannotolerans). A strain of K. drosophilarum showed with the type strain of K. lactis only 63% similarity. The strain originally described as the type strain of K. cellobiovorus nom. nud. was excluded from the genus (Q-9), and found to be conspecific with the type strain of Candida intermedia.

Cell Wall↗

Protracted diarrhoea: secondary monosaccharide malabsorption and zinc deficiency with cutaneous manifestations during total parenteral nutrition.

Protracted diarrhoea in early infancy gives rise to many diagnostic and therapeutic problems. Jejunal biopsy often reveals villous atrophy of varying degrees. Severe reduction of small intestinal absorptive area causes secondary monosaccharide malabsorption, as well as secondary disaccharide deficiency, consequences which are relevant in any attempts at oral feeding. Morphologic, metabolic, endocrinological and microbiological studies have to be undertaken in order to establish a definitive diagnosis in protracted diarrhoea, but these studies often fail to reveal the aetiology of the disease. Immunologic abnormalities like phagocyte dysfunction, thymic atrophy and hypoplasia of B-cell regions in lymph nodes might be secondary events, but some types of immunodeficiency are of primary importance in the development of protracted diarrhoea. Total parenteral nutrition in many cases has to be instituted, with all its implications and hazards: septicaemia is the most dangerous of these. Zinc deficiency and acrodermatitis enteropathica may occur during total parenteral nutrition, and zinc deficiency secondarily contributes to the symptoms of diarrhoea. Parenteral administration of zinc is able to overcome these effects.

Acrodermatitis↗

Changes of monosaccharide availability of human hybridoma lead to alteration of biological properties of human monoclonal antibody.

The effect of glucose and other monosaccharide availability in culture medium on production of antibody by human hybridomas has been studied. Human hybridoma cells C5TN produce an anti lung cancer human monoclonal antibody, and the light chain is N-glycosylated at the variable region. When the cell line was grown in the presence of various concentrations of glucose, the antibodies produced changed their antigen-binding activities. Analysis of the light chains produced under these condition revealed that four molecular-mass variant light chains ranging from about 26 to 32 kDa were secreted. The twenty six-kDa species, which corresponds to a non-glycosylated form of the light chain, was recovered after enzymatic removal of all N-linked carbohydrate chains, indicating that the source of the heterogeneity of the light chain is due to the varied glycosylation. When the C5TN cells were cultured in medium containing either fructose, mannose or galactose instead of glucose, galactose elevated the antigen binding activity of the antibody more than the other sugars. These results suggest that change of glucose availability affects the antigen-binding activity of the antibody via the alteration of the glycosylation.

Antibodies, Monoclonal↗

Evolution and kinetics of monosaccharides, disaccharides and alpha-galactosides during germination of lentils.

The effect of light and seed rinsing during the germination of lentil seeds (Lens culinaris var. vulgaris, cultivar Magda-20) on the level of monosaccharides, disaccharides and alpha-galactosides (raffinose, ciceritol and stachyose) was investigated. The total soluble sugar content corresponded to about 9% of the mature seed weight, about 65% of which was alpha-galactosides. Germination brought about a large decrease in alpha-galactosides: 18% to 40% losses after 3 days and 100% after 6 days. However, glucose, which was not detected in ungerminated seeds, as well as fructose and sucrose gradually increased during germination. The content of alpha-galactosides decreased more rapidly when germinating seeds were given 6 h light per day, but under these conditions there was also a major reduction in the levels of fructose, glucose and sucrose. Seeds rinsed daily showed a greater reduction of alpha-galactosides and an increase in the levels of fructose, glucose and sucrose. When seeds were germinated for 10 days in the dark with daily rinsing, the content of alpha-galactosides decreased gradually during the first 4 days and they were not detected after 6 days. Under these conditions, fructose, glucose and sucrose, which represented about 3% of the mature seed weight, started increasing after day 2 and represented more than 13% of the germinated seed dry weight after 10 days.

Disaccharides↗

Kinetic constants for intestinal transport of four monosaccharides determined under conditions of variable effective resistance of the unstirred water layer.

Theoretical considerations have suggested that variations in the resistance of the unstirred water layer (UWL) have a profound effect on the kinetic constants of intestinal transport. In this study, a previously validated in vitro technique was employed to determine the unidirectional flux rate of glucose, galactose, 3-O-methyl glucose and fructose into the rabbit jejunum under carefully-defined conditions of stirring of the bulk phase known to yield different values for the effective resistance of the UWL. For each monosaccharide, uptake is much greater when the resistance of the UWL is low than when high. The maximal transport rate, Jd m, of glucose was half as large as the Jd m of galactose and 3-O-methyl glucose (3-O-MG), and was twice as great as the Jd m of fructose. The apparent affinity constant, Km * of glucose is less than that of fructose, which was lower than the Km * of galactose and 3-O-MG. The use of the Lineweaver-Burk double reciprocal plot is associated with an overestimation of both Jd m and Km *. This discrepancy between the true and apparent values of the kinetic constants is much greater for lower than for higher values of Jd m and Km *; variations in the resistance of the unstirred layer influences the magnitude and direction of the discrepancy. The apparent passive permeability coefficient is similar for each sugar, but because of the different values of Jd m, passive permeation contributes relatively more to the uptake of glucose and fructose than of galactose or 3-O-MG. Under conditions of high unstirred layer resistance, differences in uptake rates of the sugars are due to differences in their Jd m rather than their Km *. Kinetic analysis is compatible with the suggestion that the glucose carriers are predominantly near the tip of the villus, whereas those for galactose and 3-O-MG are located along the entire villus and the Km * of their carriers at the tip is lower than their Km * towards the base of the villus. It is proposed that there are multiple or heterogeneous intestinal carriers for glucose, galactose and 3-O-methyl glucose in the jejunum of the rabbit.

Animals↗

Growth of Candida utilis on a mixture of monosaccharides, acetic acid and ethanol as a model of waste sulphite liquor.

Candida utilis cultivated under batch conditions in a synthetic medium with a mixture of different carbon sources utilized first D-glucose and then D-galactose, D-mannose, D-xylose, L-arabinose, ethanol and acetic acid. The effect of acetic acid was primarily a function of pH and the physiological state of the inoculum. At pH 4.5, acetic acid at a concentration of 1 g/l increased the specific growth rate, reduced time of cultivation and increased yield of the yeast dry weight. The yield from acetic acid was 61%. In the presence of a higher content of acetic acid (3--6 g/l) the yield was only 18--26%. The yield calculated only from monosaccharides increased but the yield with respect to total carbon sources was lower. The specific growth rate decreased as well. The addition of ethanol also resulted in an increase of the production and yield of the yeast dry weight but the cultivation time was prolonged. The simultaneous utilization of carbon sources of the studied mixture modelling a sulphite fermentation medium with ethanol is advantageous. However, due to physiology of the yeast, it is most suitable to cultivate a strain adapted to utilizable carbon sources in a continuous way, in the presence of their limiting concentrations in the cultivation medium.

Acetates↗

Glucosamine, a naturally occurring amino monosaccharide, suppresses the ADP-mediated platelet activation in humans.

OBJECTIVE: To evaluate the anti-thrombotic action of glucosamine, a naturally occurring amino monosaccharide, platelets were stimulated with ADP in the presence of glucosamine, and its effects on platelet functions were examined. MATERIALS AND METHODS: Human platelet-rich plasma was stimulated with 2.5 microM ADP in the presence of glucosamine (0.01 approximately 1 mM) or other aminosugars (N-acetyl-glucosamine, galactosamine or N-acetyl-galactosamine, 1 mM), and platelet aggregation was monitored. Furthermore, the effects of glucosamine on the thromboxane A2 production, release of granule contents, intracellular calcium mobilization and phosphorylation of Syk (a 72 kD protein tyrosine kinase) were evaluated following ADP-stimulation. In addition, the binding of [3H] ADP to its receptors was examined. RESULTS: Glucosamine (>0.01 mM) dose-dependently suppressed platelet aggregation in response to ADP (p < 0.05), whereas N-acetyl-glucosamine, galactosamine or N-acetyl-galactosamine (1 mM) did not affect the ADP-induced platelet aggregation. Furthermore, glucosamine (>0.1 mM) inhibited the extracellular release of granule contents (ATP and platelet factor 4) and production of thromboxane A2 from ADP-stimulated platelets (p < 0.05). Moreover, glucosamine significantly repressed the intracellular calcium mobilization at >0.1 mM and phosphorylation of Syk at >0.01 mM upon ADP-stimulation (p < 0.05). In addition, glucosamine (>0.1 mM) inhibited the binding of ADP to its receptors (p < 0.05). CONCLUSION: Glucosamine is able to suppress platelet aggregation, release of granule constituents, thromboxane A2 production, calcium mobilization and phosphorylation of Syk possibly via the inhibition of ADP-binding to the receptors. Glucosamine could be expected as a novel anti-platelet agent for thrombotic disorders due to its suppressive actions on platelets.

Adenosine Diphosphate↗

Interference by carbohydrate substrates, flavonoids, and monosaccharide derivatives on bacterial beta-D-glucuronidase assays.

Most commercially available test kits for water and foodstuffs use beta-galactosidase activity for coliforms and beta-glucuronidase activity for Escherichia coli. We tested the effects on the beta-glucuronidase activity of E. coli W3110 of substances usually present in foods and several synthetic pharmaceutical compounds. Thirteen substances were tested: three carbohydrates, four flavonoids, five monosaccharide derivatives, and dimethyl sulphoxide. In a minimum medium without any other carbon source, glucose (0.1 mM), quercetin (0.1 mM), silymarin (10 mg/L), D-gluconic acid (0.01 mM), D-gluconic acid lactone (0.01 mM), isopropyl-beta-D-thiogalacto pyranoside (1 mM), p-nitrophenyl beta-D-glucuronide (1 mM), and DMSO (1 M) completely inhibited E. coli glucuronidase activity at the above concentrations. However, the following compounds stimulated E. coli glucuronidase activity within the ranges of concentrations shown: glucose (0.0001-0.01 mM), lactose and sucrose (>0.1 mM), D-saccharic acid 1,4 lactone (0.0001-0.1 mM), p-nitrophenyl beta-D-glucuronide (0.001-0.01 mM) and DMSO (2-500 mM). In a rich culture medium that contained other carbon sources (lauryl tryptose broth) E. coli glucuronidase activity in the presence of the extra nutrients was unaffected by the test substances and therefore, under normal conditions in water or foods, they should not interfere with E. coli assays based on measurements of beta-glucuronidase activity.

Biological Assay↗

Localization of specific monosaccharides in cells of the brown alga Padina gymnospora and the relation to heavy-metal accumulation.

The brown alga Padina gymnospora has been studied due to their ecological significance and biochemical characteristics, including its high capability of heavy-metal accumulation. It has been suggested that the fucans are among the main polysaccharides related to metal binding and precipitation in cell walls. The main purpose of this work was to determine the localization of specific monosaccharides in P. gymnospora cells. In this way, the lectins Ulex europaeus agglutinin and Canavalia ensiformis concanavalin A with specificity to alpha-L-fucose and to terminal residues of alpha-D-glucosyl and alpha-D-mannosyl, respectively, were applied in young individuals. These revealed a preferential distribution of alpha-L-fucose at cell walls near the external surface in cortical cells and near the plasmalemma in cortical and medullar cells. The distribution of alpha-L-fucose in cell walls indicates the distribution of sulfated polysaccharides (sulfated fucans) that colocalize with the heavy-metal granules (Zn and Cd) described in previous works. Therefore, our results suggest that alpha-L-fucose participates in the nucleation and immobilization of heavy metals in P. gymnospora cell walls. An intense labeling of U. europaeus agglutinin and a weak labeling of concanavalin A was also observed in physodes. X-ray microanalysis revealed the presence of zinc, sulfur, and calcium in physodes of algae collected in a heavy-metal-contaminated area. Besides the affinity between polyphenolic compounds and heavy metals, it is suggested that the mechanism of metal binding by physodes could be related to the presence of sulfated fucans.

Cell Wall↗

The changes in monosaccharide composition of immunoglobulin G in the course of rheumatoid arthritis.

The objective of this study was to determine whether galactosylation of immunoglobulin G (IgG) in patients with rheumatoid arthritis (RA) correlates with severity and duration of illness. Serum IgG glycosylation from 50 patients with RA in comparison with 30 healthy controls was analyzed. IgG from sera was isolated and monosaccharide composition was determined by means of gas chromatography. Ratio of galactose to mannose content was calculated. Patients were divided into groups according to three different criteria: disease duration, severity of RA (disease activity score index), and radiological degree of advancement of illness according to Steinbrocker. In patients with RA, significant decrease (p<0,01) of galactose ratio was observed in comparison with healthy control. In patients with long duration of RA (more than 15 years), significant decrease of galactose (p<0.05) ratio in comparison with patients who have had arthritis for less then 5 years was observed. For the group of patients with severe RA, we found reduction of galactose (p<0.001) ratio vs the group of patients in remission. For those patients who had radiological stage IV according to Steinbrocker, IgG galactose (p<0.01) content per oligosaccharide chain were also more decreased than in those patients who had stage I RA. Decreased galactosylation and of IgG in RA was observed. The lack of this carbohydrate component of IgG correlates with severity and duration of RA and could be used in monitoring the progression in early arthritis.

Adult↗

Chromogenic labeling of monosaccharides using 4'-N,N-dimethylamino-4-aminoazobenzene.

Twenty-three monosaccharides, e.g., D- or L-pentoses, D- or L-hexoses, heptose, 2- or 6-deoxyhexoses, 2-deoxy-2-aminohexoses, hexuronic acids, and N-acetylmuramic acid, were coupled to the azo dye 4'-N,N-dimethylamino-4-aminoazobenzene by reductive amination using sodium cyanoborohydride as reducing agent and in the presence of pentaerythritol. The structure of the colored glycamines was established by mass spectrometry. The average yield of the reaction was more than 80%. The sugar derivatives were separated either by silica-gel thin-layer chromatography or by high-performance liquid chromatography. Spectrophotometric quantitation was performed in the visible range at the picomole level. The method was applied to the determination of the sugar composition of the glycosphingolipid globotetraosyl ceramide and the human milk oligosaccharide lacto-N-fucopentaose I.

Amination↗

High-performance liquid chromatography of sialic acid-containing oligosaccharides and acidic monosaccharides.

Many sialic acid-containing oligosaccharides and five acidic monosaccharides have been separated by high-performance anion-exchange chromatography using a Dionex AS6 ion-exchange column eluted with aqueous 50 mM NaOH plus 50-175 mM sodium acetate. Using a pulsed amperometric detector, as little as 50 pmol oligosaccharide can be detected. Many factors, such as the presence of fucosyl groups or sialyl groups, glycosidic linkage positions, and branching structure, can have a tremendous influence on overall acidity of the oligosaccharide, which can lead to excellent separations and make this method an important addition to existing alternatives for the separation of sialic acid-containing oligosaccharides.

Carbohydrate Sequence↗