Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “GALACTOSE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,045 records · Page 58Linked to original sources
PubMed1988

Inhibition by cadmium of D-galactose and L-phenylalanine transport by rat intestine in vitro.

The effect of cadmium (CdCl2) on galactose and phenylalanine uptake by rat everted intestinal rings has been studied. The rings were preincubated (15 min) and incubated (5 min) in the presence of Cd. Galactose uptake (from 0.5 mM to 10 mM) was inhibited by 0.5 mM Cd about 25%. Only the phlorizin-dependent galactose transport was affected by cadmium, being a non-competitive type inhibition. A 15 min washing with saline solution significantly reduced the cadmium induced inhibition, which was practically reversed by washing with 5 mM EDTA. The uptake of 0.5 mM phenylalanine was not affected by 0.5 mM Cd but it was depressed by 1 mM Cd. Such inhibition was exerted on the sodium-dependent phenylaline transport. Washing with 5 mM EDTA diminished only slightly the inhibition of the transport by cadmium. It is suggested that the inhibition of intestinal transport of galactose and phenylalanine by cadmium may be due to its reversible interaction with metal-binding ligands, possibly sulfhydryl groups, related to the luminal transport systems.

Animals↗
PubMed1988

A trial of alloreactive T-cell depletion using biotinylated galactose oxidase for the prevention of acute graft-versus-host diseases.

Galactose oxidase was labelled onto the surface of mitomycin-C treated splenic lymphocytes from BALB/C mice (H-2d, Mlsb). Mouse splenic lymphocytes from DBA/2 (H-2d, Mlsa) mixed with the galactose oxidase labelled BALB/C lymphocytes allowed DBA/2 cells which recognized the Mlsb on the BALB/C cells to make direct contact with the galactose oxidase labelled BALB/C cells. By adding galactose, sodium iodide and catalase to the mixture, the contacting stimulator cells will generate hydrogen peroxide in the vicinity of the contacting responder cells and the iodine ions will exert a toxic effect on the responder cells while non-specific cytotoxicity was prevented by catalase. When fresh mitomycin-C treated BALB/C lymphocytes were added to the cell mixture, the mixed lymphocyte response against BALB/C cells by the treated DBA/2 lymphocytes was abolished. On the other hand, when fresh mitomycin-C treated lymphocytes from C57BL/6 mice (H-2b, Mlsb) were mixed with the treated DBA/2 cells, the mixed lymphocyte response against C57BL/6 cells by the treated DBA/2 lymphocytes was partially retained. Therefore, although some non-specific cytotoxicity was present, a method to deplete specific T-lymphocytes that recognize major histocompatibility antigen from a mixed cell population while maintaining immune responsiveness towards other antigens was developed. This method may have a beneficial effect on the control of post-transplant immunity and may be used as a prophylaxis of graft-versus-host disease.

Animals↗
PubMed1988

Effect of galactose on systemic hemodynamics and blood flow rate in normal and tumor tissues in rats.

The effect of galactose on systemic hemodynamics and blood flow rate of Walker 256 carcinomas and several normal tissues of unanesthetized, unrestrained female Sprague-Dawley rats was measured, using the radioactive microsphere technique, prior to and at 30 and 60 min after galactose administration (6 g/kg body weight, i.v.). Whereas heart rate remained unchanged following injection, cardiac output (CO) and cardiac index decreased by 35% (P less than 0.05). Mean arterial pressure immediately decreased during the injection but then increased reaching a value 10% (P less than 0.05) above the baseline 30 min following injection. Stroke volume (SV) decreased by 30% (P less than 0.05) and total peripheral resistance increased by 65% (P less than 0.05). Redistribution of blood flow, expressed as %CO, among normal tissues was seen to the brain, kidneys, liver, jejunum, and hindlimb muscle and away from the pancreas, stomach, and skin. Changes in %CO to the spleen, colon, forelimb muscle, and peritumor tissue were not significant. Blood flow rate in most normal tissues either decreased or remained constant following injection. An exception was in the liver where blood flow significantly increased. Blood flow significantly decreased in the tumor (approximately 60%) and this reduction in blood flow was larger than the reduction in CO. These results suggest that (a) the effect of galactose on systemic hemodynamics and blood flow rate are similar to those produced by glucose; (b) reduction in blood flow rate in tumors is due to both systemic and local effects; and (c) changes in blood flow to normal tissues should not be disregarded when using galactose in combination with hyperthermia and/or chemotherapy for cancer treatment.

Animals↗
PubMed1986

Influence of aerobic energy deficit, ouabain and harmaline on the phenylalanine and galactose active transport by snail intestine.

The effect of anaerobiosis (N2 bubbling of the medium) or 10(-4) M dinitrophenol on the penetration of 0.5 mM Phe in snail and rat everted intestine, in 2 min and 30 min incubation periods, has been studied. The aerobic energy deficit inhibits the amino acid net entry in both species, but whereas the active transport is annulled in rat, snail intestine is capable of continuing to accumulate Phe against a gradient. The prolonged action (30 min of preincubation) of 1 mM ouabain inhibits 0.1 mM Phe and 0.1 mM galactose entry in snail intestine. Amino acid uptake is far higher than the one obtained in the absence of Na+, in which condition Phe keeps accumulating against a gradient in the tissue water. Galactose active transport, instead, becomes null in the presence of the glucoside or in the absence of Na+. One mM harmaline is able to inhibit the initial entry of galactose into the tissue, while higher than 5 mM concentrations are required to inhibit that of Phe. Results confirm that snail intestine is capable of easily carrying out active transport processes with energy from anaerobic origin. On the other hand Phe transport is less sensitive to the absence of Na+, presence of ouabain or harmaline than that of galactose, so that contrary to what has been observed for the sugar, the active transport of the amino acid is not annulled in any of the three conditions.

Anaerobiosis↗
PubMed1986

1H NMR investigation of the binding of methyl-beta-D-galactoses with sialic acid residues on hepatic binding protein--the effect of divalent calcium ions.

The present study is a proton NMR investigation of the influence of Ca2+ on the interaction between the intact sialic acid residues on HBP (Hepatic Binding Protein) and methyl-beta-D-galactoses. The proton NMR spectra of HBP and methyl-beta-D-galactose mixing solution at different Ca2+ concentration have been measured. The analysis of the experimental results indicates that Ca2+ participates in the binding of sialic acid residues on HBP with methyl-beta-D-galactoses and this enables the galactose molecules to be in stable bound state. The proton NMR spectra of the samples containing EDTA have confirmed this conclusion.

Animals↗
PubMed1979

Carbohydrate transport in Moniliformis dubius (Acanthocephala). III. Post-absorptive fate of fructose, mannose, and galactose.

The initial metabolism of fructose, mannose, and galactose in Moniliformis dubius (M. moniliformis; Acanthocephala) was examined following brief aerobic incubations in 14C-labeled substrate. The pattern of incorporation of radioactivity from 14C-fructose and 14C-mannose into intermediates of hexose metabolism was indistinguishable from that reported elsewhere for the initial post-absorptive metabolism of 14C-glucose under comparable conditions; these hexoses were phosphorylated rapidly following their absorption, and much of the radioactivity absorbed as mannose or fructose was recovered in the nonreducing disaccharide trehalose [alpha-D-glucopyranosyl-(1 leads to 1)-alpha-D-glucopyranoside]. 14C-Galactose was phosphorylated less readily than the other hexoses. More than half of the radioactivity absorbed as galactose was incorporated into disaccharide; some of the galactose-derived disaccharide had properties suggesting the presence of a galactosyl moiety. Incorporation of radioactivity from any of the hexoses into glycogen was minimal. The extensive incorporation of hexose moieties into trehalose or a trehalose-like disaccharide rather than glycogen underscores the probable importance of trehalose metabolism to carbohydrate assimilation in Moniliformis. Physiological factors which might favor trehalose biosynthesis over glycogenesis are considered.

Absorption↗
PubMed1979

Galactose oxidase. An enzyme with lectin properties.

Galactose oxidase interacts with immobilized D-galactosyl residues and related immobilized and free sugars under the conditions of affinity electrophoresis in polyacrylamide gel and agglutinates sialidase-treated human erythrocytes. The agglutination is also inhibited by D-galactose and its derivatives and is temperature dependent. The sugar binding and hemagglutinating activity are preserved after removal of Cu2+ essential for enzymic activity. These properties are very similar to those of some typical lectins; however, a number of D-galactose specific lectins do not possess any detectable galactose oxidase activity.

Carbohydrate Metabolism↗
PubMed1979

Quantitative gas-liquid chromatography of neutral sugars in human serum glycoproteins. Fucose, mannose, and galactose as predictors in ovarian and small cell lung carcinoma.

A precise and accurate gas-liquid chromatographic (GLC) method has been developed for the quantitative analysis of the neutral sugars L-fucose (6-deoxygalactose), mannose, galactose, and glucose in ethanol precipitates of human serum proteins. The chromatographic conditions and sample preparation resulted in short analysis time (20 min per run) and made routine analyses practicable (twelve samples per day). The alditol acetate derivatization yielded single derivatives for each sugar. Complete separation was achieved on a 2.0 m X 2 mm I.D. column with 2.0% Silar-7CP on Chromosorb W AW 80--100 mesh. The results of hydrolysis showed that the release of fucose and galactose preceded the release of mannose. Hydrolysis with AG 50 W-X8 (H+) ion-exchange resin in 0.5 N HCl at 100 degrees for 7 h optimized glycosidic bond cleavage with only minimal destruction of fucose, mannose and galactose. A combination of strong cation- and anion-exchange resin columns was used to remove chromatographic background of peptides, amino acids, amino sugars, and inorganic ions. An average R.S.D. of less than 4% with recovery of greater than 86% for the three sugars was achieved. The homogeneity of the chromatographic peaks for the neutral sugars of normal human serum glycoproteins was confirmed by GLC--mass spectrometry. Significantly elevated ratios of fucose, galactose, and mannose to serum protein were observed for patients with small cell lung and ovarian carcinomas.

Carcinoma↗
PubMed1983

Purification and properties of two enzymes catalyzing galactose transfer to GM2 ganglioside from rat liver Golgi.

An enzyme activity which catalyzed the transfer of galactose from UDP-galactose to GM2 ganglioside was demonstrated in rat liver homogenate and enriched 38-fold in specific activity by preparation of Golgi membranes. This activity could be solubilized from Golgi membranes by sonication and extraction with 1% Triton X-100. The solubilized activity catalyzed the formation of GM1 ganglioside and was completely dependent upon the addition of acceptor. The rate of galactose incorporation was constant for up to 5 h at 30 degrees C. This enzyme activity was further purified by gel filtration on Sepharose CL-6B and ion exchange chromatography on DEAE-Sepharose. The elution position on gel filtration corresponded to a molecular weight for the enzyme of 38,000 which was in good agreement with that obtained by sedimentation velocity studies. Ion exchange chromatography resolved GM2 ganglioside galactosyltransferase into two species. The more basic enzyme (I) comprising 28% of the recovered activity was not retarded by the column, whereas enzyme II was eluted from the resin following the application of a salt gradient. Net purification was 120- to 140-fold for each enzyme with a total recovery of 42%. Unlike the activity in the Golgi extract, the purified enzymes I and II were labile to freezing and could be stored at -20 degrees C only in the presence of 50% glycerol. Both enzymes I and II had similar molecular weights and Michaelis constants and both had a strict requirement for Mn2+. Properties which distinguish the two enzymes included pH optima (enzyme I 7.0, enzyme II 6.0) and surfactant requirements. Neither enzyme was active following removal of Triton X-100 from the preparation. Among a series of glycolipids tested for ability to serve as substrates for galactose transfer only GM2 and asialo-GM2 ganglioside served as acceptors.

Animals↗
PubMed1983

[Existence of UDP galactose: galactosyltransferase activity at the external surface of cultured neurons].

The existence of UDP-galactose:galactosyltransferase activities at the external surface of cultured neurons from chick embryo hemispheres, was demonstrated. [14C]-galactose was transferred upon cellular substrates present on the neuronal surface and upon exogenous substrates (ovomucoïd) bound to Sepharose beads. The activity of ectogalactosyltransferase was not due to a leakage of intracellular enzymes into the incubation medium nor to an intracellular enzymatic activity utilizing [14C]-galactose obtained from the hydrolysis of UDP-[14C]-galactose. Kinetics of these ectogalactosyltransferases were analysed. The results support the hypothesis of a communication and/or interaction among the nerve cell surfaces via glycoconjugates or their biosynthetic enzymes.

Animals↗
PubMed1984

[Separate factors influencing the interaction of carbohydrate- containing liposomes with galactose-specific lectins].

Some natural (Gal-Cer, Lac-Cer, desyalylated gangliosides) and synthetic (HMGal) glycolipids differing in the length of the bridge linking the terminal galactose with the hydrophobic moiety were incorporated into the liposome membranes. The precipitation of the thus obtained vesicles induced by galactose-specific lectin RCA was studied. It was shown that when the amount of the glycolipids used for the incorporation into the liposomes (1 mol. %) was the same, the vesicles with HMGal or Gal-Cer incorporated into them did not precipitate in the presence of lectin, whereas the liposomes with incorporated Lac-Cer or desyalylated gangliosides did precipitate. It was thus concluded that in order for galactose-containing liposomes precipitation by lectin RCA1 to be induced, galactose should be separated from the liposome membrane with a distance not less than 7 A. The nature of lectin-induced nonspecific precipitation of ganglioside-containing liposomes, ganglioside mycelles and cardiolipin-lecithine liposomes containing lactosylceramide was investigated. Some nonspecific ionic interactions of negatively charged liposomes and ganglioside mycelles with lectin were observed, which disappeared with a rise in the NaCl concentration up to 150-200 mM.

Animals↗
PubMedDate not supplied

Gastric emptying of lactose and glucose-galactose in patients with low intestinal lactase activity.

To test the hypothesis that in subjects with low intestinal lactase activity (LLA) lactose solutions leaves the stomach at an abnormally fast rate, we have measured the gastric emptying rate of solutions of lactose and glucose-galactose in patients with LLA (n = 9) and in control subjects with high intestinal lactase levels (n = 7) as proved by the assay of disaccharidases in specimens of intestinal mucosa. The volume of the test meals was 300 ml. Lactose solutions contain 50 g of disaccharide and glucose-galactose solutions contain 25 g of each monosaccharide. The volumes remaining in the stomach at different times after the intragastric instillation of the test meals were estimated by the double sampling test meal. In the control group, minor differences between lactose and glucose-galactose gastric emptying rates was found. By contrast, in LLA patients, the lactose meal left the stomach at a significantly faster rate than the glucose-galactose test meal. These findings support previous evidence obtained in patients with putatively low intestinal lactase activity and are consistent with the view that duodenal osmoreceptors, whose excitation results in inhibition of gastric emptying, lie deeper than the disaccharidases in intestinal mucosa. Thus, incomplete hydrolysis of lactose results in a faster than normal gastric emptying rate of the sugar and this may contribute to the symptoms found in LLA patients after milk ingestion.

Adult↗
PubMedDate not supplied

Systems for generating and detecting mutations in the galactose operon promoter region.

We discuss the use of plasmid systems which enable us to generate and detect mutations in the Escherichia coli galactose operon promoter region. We describe the isolation of mutants which map the galactose promoters and which pinpoint the sites for the binding of the cyclic AMP-binding protein (CRP) and the galactose repressor. Finally, we describe how such mutations can be transferred from the plasmid systems to the intact galactose operon on the host chromosome.

Bacterial Proteins↗
PubMedDate not supplied

[Congential malabsorption of glucose and galactose in 2 brothers].

Congeneeital glucose-galactose malabsorption is a rare clinical entity transmitted by autossomic recessive gen. The defect is in the small intestinal active transport system which is shared by glucose and galactose. Diarrhea and failure to thrive from the first week of life are the prominent symptoms. We report two sibs from consaguineous parents with diarrhea and failure to thrive since they were born. Both children had glucose and galactose malabsorption but tolerated well formula containing fructose as the only source of carbohydrate. They showed flat blood glucose curves when tested with glucose and galactose loads but normal increments of the sugar blood levels with fructose load. The small intestinal biopsy performed in both patients revealed normal villous pattern. When put under a diet containing fructose as the only source of carbohydrate, both patients had their symptoms subsided and reassumed the normal pattern of growth.

Body Weight↗
PubMed1980

Continuous-flow fluorometry of low galactose concentrations in blood or plasma.

Clearance of 0-100 mg/L concentrations of galactose from the blood depends on nutrient hepatic blood flow. We can measure such concentrations, which was not previously possible, by a continuous-flow method involving the use of galactose oxidase and peroxidase, the latter being coupled to a fluorogenic substrate, p-hydroxyphenylacetic acid. Interfering substances in the peroxidase reaction are removed by zinc/alkali precipitation. Sensitivity is maximized by using saturating concentrations of the enzymes and substrate. In prepared plasma test samples with galactose concentrations of 10, 40, 70, and 100 mg/L, the within-run CV's ranged from 2.1 to 8.6%, and day-to-day CV's from 2.2 to 17.2%, the largest CV's being for the 10 mg/L concentration. Normal subjects are shown to clear galactose more efficiently than subjects with moderate cirrhosis.

Anticoagulants↗
PubMed1980

Carbohydrate-mediated clearance of immune complexes from the circulation. A role for galactose residues in the hepatic uptake of IgG-antigen complexes.

The purpose of these experiments was to evaluate the hypothesis that galactose residues on IgG mediate the clearance of IgG.antigen complexes from the circulation. After 28 days of immunization of rats with bovine serum albumin (BSA), approximately 90% of anti-BSA antibody was IgG; the circulating half-life of trace amounts of BSA antigen in immunized rats was 6 min, compared to 24 h in nonimmunized rats. Similarly, soluble IgG.125I-BSA complexes formed in vitro, under conditions of antibody excess, had a circulating half-life of 4 min in normal rats. For both antigen in immunized rats, or IgG.125I-BSA complexes in normal animals, clearance was markedly inhibited by pre- or co-injection of asialofetuin, but was insensitive to large doses of fetuin, ovalbumin, or mannan. Liver parenchymal cells were the major site of uptake of complexes formed in vivo or in vitro. In vitro binding of IgG.125I-BSA complexes by isolated hepatocytes was effectively competed by asialofetuin, asialo-orosomucoid, galactose, and N-acetylgalactosamine, but was unaffected by fetuin, orosomucoid, ovalbumin, mannan, or mannose. These data suggest that antigen-induced conformational changes in IgG result in both recognition of galactose residues on IgG and clearance of IgG-immune complexes from the circulation by the galactose-specific receptor in hepatic parenchymal cells.

Animals↗
PubMed1980

[Age-dependence of fructose and galactose tolerance following intravenous loading in piglets].

Fructose tolerance tests were applied to 54 piglets, aged between zero and 20 hours, two and three, five and seven, as well as 20 and 30 days. Fructose injections per kilogram of body weight were 0.5 g and 1.0 g. Galactose tolerance tests were applied to 33 piglets, aged between zero and 20 hours as well as between five and seven or 20 and 35 days. The galactose dose per kilogram of body weight was 0.5 g. Very slow or no fructose elimination at all was recordable from the circulation of animals, aged between zero and 20 hours, yet, with elimination rates being accelerated along with growing age. Piglets, aged between 20 and 30 days, eliminated fructose from the blood just as fast as glucose (th = 0.49 +/- 0.11 hr). Fructose depressed the glucose levels in the blood in animals, aged between five and seven days, but it failed to do so in animals, aged between 20 and 30 days, Galactose was found to be eliminated speedily from the circulation, that is immediately after birth, a maximum being reached at an age between five and seven days (th = 0.11 +/- 0.02 hr). Fructose space in piglets, aged between five and seven or between 20 and 30 days, was found to be significantly below that recorded from the two younger age groups. Galactose space in piglets, aged between five and seven days, was significantly below that of the other two groups.

Aging↗
PubMed1994

Specific interaction of the Escherichia coli chaperone GroEL (60-KDA heat shock protein) with the liganded form of the galactose binding protein.

The Escherichia coli chaperone GroEL interacts more strongly with the liganded form of the galactose binding protein (the galactose binding protein-galactose complex), than with its unliganded form. This specific interaction is reflected by the stimulation of the ATPase activity of GroEL by the liganded galactose binding protein. Interactions between native proteins and chaperones could be more frequent than generally suspected, and may help to detect protein conformational changes.

Adenosine Triphosphatases↗