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Results for “Glycodeoxycholic Acid”

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PubMed1987

Activation of erythrocyte membrane Ca2+-ATPase by calpain.

Ca2+-ATPase of erythrocyte membranes, prepared from erythrocytes substantially removed of contaminating leukocytes, was found to be activated by calpain isolated from the same source. Saponin or glycodeoxycholate treatment of membranes was essential for elicitation of the calpain response. Unlike the membrane bound ATPase, solubilized ATPase was inactivated by calpain. Digestion of membranes with the protease did not affect the Km (ATP) of Ca2+-ATPase though stimulation of the membrane ATPase by calmodulin could be partially substituted by calpain treatment. As compared with control, Ca2+-ATPase of calpain-digested membranes attained maximal activity at a lower free Ca2+ concentration.

Animals↗
PubMed1989

Ca2+-mediated activation of human erythrocyte membrane Ca2+-ATPase.

Ca2+-ATPase of human erythrocyte membranes, after being washed to remove Ca2+ after incubation with the ion, was found to be activated. Stimulation of the ATPase was related neither to fluidity change nor to cytoskeletal degradation of the membranes mediated by Ca2+. Activation of the transport enzyme was also unaffected by detergent treatment of the membrane, but was suppressed when leupeptin was included during incubation of the membranes with Ca2+. Stimulation of the ATPase by a membrane-associated Ca2+-dependent proteinase was thus suggested. Much less 138 kDa Ca2+-ATPase protein could be harvested from a Triton extract of membranes incubated with Ca2+ than without Ca2+. Activity of the activated enzyme could not be further elevated by exogenous calpain, even after treatment of the membranes with glycodeoxycholate. There was also an overlap in the effect of calmodulin and the Ca2+-mediated stimulation of membrane Ca2+-ATPase. While Km(ATP) of the stimulated ATPase remained unchanged, a significant drop in the free-Ca2+ concentration for half-maximal activation of the enzyme was observed.

Calcium↗
PubMed1986

Selective solubilization of physalaemin-type substance P binding sites from rat brain membranes by glycodeoxycholate and NaCl.

Active substance P binding sites were solubilized from rat brain membranes by treatment with 0.125% sodium glycodeoxycholate and 1 M NaCl. About 50% of the binding activity in membrane-bound binding sites was recovered in the solubilized fraction after centrifugation at 105,000 g for 1 h. [3H]Substance P absorbed extensively to glass tubes and glass filters, but the absorption was greatly reduced by siliconizing glass tubes and preincubating glass filters in a solution containing poly-D-lysine and bovine serum albumin. [3H]Substance P was found to bind the solubilized receptors in a saturable fashion with a Bmax of 145 fmol/mg protein and a Kd of 4.6 nM, and these bindings were completely replaced by low concentrations of unlabeled substance P and physalaemin.

Animals↗
PubMed1987

Binding characteristics of [3H]opioid ligands to active opioid binding sites solubilized from rat brain membranes by glycodeoxycholate and NaCl: the recovery of binding activity by dilution.

This paper describes the binding properties of [3H]peptidergic opioid ligands to binding sites solubilized from rat brain membranes by the treatment with 0.125% sodium glycodeoxycholate and 1 M NaCl. The highest amount of the specific binding of [3H]-[D-Ala2-, Met5]enkephalinamide was obtainable when 10-fold diluted solubilized preparations were incubated in the presence of 0.1 mM MnCl2 and 100 mM NaCl at 0 degree C (on ice) for 3 h. With this assay condition, the significant binding of following [3H]opioid ligands, which have been thought to be selective for receptor types, was also observed: [3H]-[D-Ala2, MePhe4, Gly-ol5]enkephalin (mu-type), [3H]-[D-Ala2, D-Leu5]enkephalin (delta-type) and [3H]dynorphin1-9 (kappa-type). The number of binding sites in solubilized preparations for each [3H]ligand corresponded to 40-50% recovery of original membrane-bound binding sites. The Scatchard plot of the concentration-saturation binding curve showed only one class of binding sites, with a high affinity for each [3H]ligand. Apparent dissociation constants between solubilized receptors and [3H]ligands were the same as membrane-bound ones, but the ligand specificity for each receptor-type, which was examined by binding inhibition tests with unlabeled ligands, decreased. Present results indicate that heterogeneous opioid receptors in rat brain membranes seem to be transformed into less heterogeneous forms through the treatment with glycodeoxycholate and NaCl and the dilution process.

Animals↗
PubMed1986

A model of hemorrhagic pancreatitis in cats--role of 16,16-dimethyl prostaglandin E2.

Acute edematous pancreatitis was induced in cats by perfusing activated pancreatic enzymes through their pancreatic ducts. The ducts had been made permeable to large molecules by one of two techniques. The cats either received ethanol (2 ml/kg every 8 h) and aspirin (25 mg/kg every 8 h) orally for 48 h or had their pancreatic ducts perfused for 1 h with 7.5 mM glycodeoxycholate. When the same procedure was followed, but using 16,16-dimethyl prostaglandin E2 (dmPGE2) (2 micrograms/kg X h infused intravenously for 1 h before and during ductal perfusion with activated enzymes), hemorrhagic pancreatitis developed instead. To investigate whether an increase in pancreatic blood flow or microvascular permeability (both caused by dmPGE2) was important in this phenomenon, we tested the effects of isoproterenol (which increased blood flow) and histamine (which increased microvascular permeability) in the model. Thus in similar experiments, either isoproterenol (0.3 micrograms/kg . min) or histamine phosphate (2 micrograms/kg . min) was infused instead of dmPGE2. The animals that received histamine also developed hemorrhagic pancreatitis. Those that received isoproterenol did not. These observations suggested that an increase in microvascular permeability in the pancreas converted edematous pancreatitis to hemorrhagic pancreatitis. These findings suggest also that clinical studies using prostaglandins to treat patients with pancreatitis should be approached with caution.

16,16-Dimethylprostaglandin E2↗
PubMed1992

Trypsinogen-activation peptides in experimental rat pancreatitis: prognostic implications and histopathologic correlates.

Intrapancreatic activation of trypsinogens is believed to occur either as a cause or a consequence of acute pancreatitis and to be associated with the more severe forms of the disease. Trypsinogen-activation peptides (TAPs) were measured in plasma, urine, and ascites of rats (n = 54) assigned to different pancreatitis-inducing regimens reproducing the entire spectrum of severity. Compared with survivors, nonsurvivors at 9 hours had significantly higher TAP levels in plasma at 3 hours (P = 0.0001), urine (peak, 1-4 hours) (P = 0.004), and ascites (P = 0.0001) after death. Stepwise discriminant analysis showed that TAP in urine and plasma were the most accurate predictors of outcome (88.2% of animals) compared with other routine laboratory parameters. Morphometric analysis showed that the best histopathologic correlates of TAP elevation were acinar necrosis and intrapancreatic hemorrhage. In a second series of experiments using a homogeneous technique of induction producing pancreatitis with a mortality of 55% at 48 hours, plasma TAP level at 3 hours (cutoff, 0.5 nmol/L) and/or urinary TAP level (peak, 1-6 hours; cutoff, 25 nmol/L) accurately predicted outcome in 85% of animals. It is concluded that the TAP assay gives an accurate early prediction of outcome in different pancreatitis models and correlates best with acinar necrosis and hemorrhage.

Acute Disease↗
PubMed1996

Microemulsion and micellar electrokinetic chromatography of steroids.

A mixture of ten steroids was separated by microemulsion and micellar (SDS and glycodeoxycholate) electrokinetic chromatography systems. Separations were done on a 50 cm (to the detector) x 50 microns I.D. fused-silica capillary. Complete separation of all the test compounds in the micellar mode was obtained with glycodeoxycholate (50 mM) in 25 mM borate buffer, pH 6.5, as the micelle-forming agent. The best results, however, were obtained using microemulsion electrokinetic chromatography in which higher aliphatic alcohols were used as the microemulsion-forming modifiers. The system consisted of n-hexanol (0.81%), SDS (3.31%) and n-butanol (6.61%) in 20 mM phosphate buffer, pH 10.0 (89.28%, w/w). In the microemulsion mode, linear calibration for steroid standards was obtained in the concentration range 3 x 10(-4)-3 x 10(-5) mol 1(-1) with a detection limit of 1 pmol. The method was validated and applied to an 11 beta-hydroxysteroid dehydrogenase assay in tissues.

Chromatography↗
PubMed1994

Use of ionic detergents for enterovirus recovery from waste water.

Virus recovery from poliovirus-seeded waste water was attempted after treatment of the samples with ionic detergents in the presence of acoustic energy. Viral titers strongly fluctuated depending upon concentration and chemical structure of the detergent as well as upon the dissolved organic content of the aqueous samples. Supplementation of the cellular monolayers with an additional amount of cell culture medium or with a nonionic detergent in a subcytotoxic concentration 48 h after inoculation partly induced cytopathic effects in silent dilution steps. Since, in the presence of the same detergent, viral recovery rates varied with the type of waste water, titer-conditioning activity of detergents was suggested to depend upon their effective critical micellization concentration. Especially for virus recovery from concentrated waste water, treatment with strongly disruptive detergents such as sodium dodecylsulfate revealed to be much more efficient than with the less hydrophilic sodium N-laurylsarcosine, sodium glycodeoxycholate or lauryldimethylamine-oxide, whereas the opposite seemed to be the case if virus recovery from filtrate samples were to be optimized. The mechanisms by which viral particles become infectious for the cell appear to be triggered by general principles of equilibrium thermodynamics, which means that interactions between viral surface proteins and cellular receptor molecules seem to reflect the tendency of these reagents to assume the energetically most favored orientation.

Animals↗
PubMed2006

Structure of sodium glycodeoxycholate micellar aggregates from small-angle X-ray scattering and light-scattering techniques.

Small-angle X-ray scattering (SAXS) and dynamic light scattering (DLS) measurements were accomplished on sodium glycodeoxycholate (NaGDC) aqueous electrolyte solutions as a function of NaGDC and NaCl concentrations with the aim to determine with satisfactory approximation the NaGDC micellar aggregate structure at a gross molecular level, assuming monodispersity. Different conditions of interparticle interactions by varying ionic strength (NaCl concentration from 0 to 0.70 M) and NaGDC concentration (from 0.02 to 0.10 M) were studied. Smeared scattering intensities and electron pair distance distribution functions, radii of gyration, and aggregate heights are in satisfactory agreement with the corresponding functions calculated using a 2(1) helix as model. It is formed by trimers, each one composed by three NaGDC and nine H2O molecules related by a 3-fold rotation axis, and can be described by a hollow cylinder, probably filled by water molecules, characterized by a conventional radius of 23.7 A and a trimer repeat along the helical axis of 3.6 A. The helix is considerably inhomogeneous since the volume of the cylinder occupied by NaGDC molecules is less than one-third of the total. On the other hand, calculations performed with the average radial electronic density of the helix without water molecules or totally filled by water molecules (a NaGDC/H2O molecular ratio of about 1/50) or by using a three-shell average radial electronic density, independently evaluated on absolute scale, do not show significant differences, thus supporting the helical model. The aggregate size increases for all the samples by increasing either the NaCl or NaGDC concentration. The NaGDC low concentration (0.02 M) samples with NaCl within the range 0.30-0.70 M are characterized by short cylindrical aggregates that do not give rise to sensible interference effects. This assertion is supported by the satisfactory fit between the observed apparent mean hydrodynamic radii and the calculated ones by means of the method of Ortega and Garcia de la Torre (J. Chem. Phys. 2003, 119, 9914), valid for rods with a length-to-diameter ratio > or = 0.1 in dilute solution (noninteracting rods). The NaGDC moderate concentration (0.10 M) samples with NaCl within the range 0.20-0.60 M are characterized by cylindrical aggregates that, in the presence of repulsive Coulombic interactions progressively more and more screened, produce interference effects, due to the hard-body repulsion and attractive forces, but the agreement between observed and calculated SAXS data is satisfactory. The results of the low and moderate NaGDC concentration samples seem to indicate that the aggregation number increase, produced by adding 0.10 M NaCl, is constant within an ionic strength range and occurs by the addition of oligomers formed by trimers. The samples with a variable NaGDC concentration (0.02-0.10 M) at a fixed and high NaCl concentration (0.6 M) contain cylindrical aggregates that give rise to an attractive term effect prevailing on the hard-body repulsive one. The same situation seems to occur in the NaGDC moderate concentration samples.

Glycodeoxycholic Acid↗
PubMed1996

In-vivo buccal delivery of fluorescein isothiocyanate-dextran 4400 with glycodeoxycholate as an absorption enhancer in pigs.

Buccal delivery of fluorescein isothiocyanate labeled dextran 4400 (FD4) was investigated in-vivo in pigs. The delivery device consisted of an application chamber with a solution of FD4 and was adhered to the buccal mucosa for 4 h using an adhesive patch. A randomized crossover study including intravenous administration and buccal delivery without and with 10 mM sodium glycodeoxycholate (GDC) as absorption enhancer was performed in five pigs. After buccal administration, steady state plasma levels were rapidly reached. Coadministration of 10 mM GDC increased the absolute bioavailability of FD4 from 1.8 +/- 0.5% to 12.7 +/- 2.0%. Since FD4 is a macromolecular and hydrophilic compound such as peptide and protein drugs, buccal delivery would provide an adequate alternative to the parenteral administration of these drugs.

Absorption↗
PubMed1996

In vivo buccal delivery of the peptide drug buserelin with glycodeoxycholate as an absorption enhancer in pigs.

PURPOSE: To study the potential of buccal delivery of the peptide drug in pigs. METHODS: Intravenous administration and buccal delivery without and with 10 mM sodium glycodeoxycholate (GDC) as absorption enhancer were investigated as a randomised cross-over study in six pigs. The buccal delivery device consisted of an application chamber with a solution of buserelin and was attached to the buccal mucosa for 4 hours using an adhesive patch. RESULTS: Buccal administration of buserelin resulted in rapidly reached steady state plasma levels. The absolute bioavailability of the peptide after buccal delivery for 4 hours could be increased from 1.0 +/- 0.3 to 5.3 +/- 1.1% (mean +/- SD.) by co-administration of 10 mM GDC (0.45% w/v)). CONCLUSIONS: The results of this study demonstrate that buccal administration with the use of absorption enhancers is a useful approach for the delivery of peptide drugs such as buserelin.

Administration, Oral↗
PubMed1981

Specific one-stage method for assay of enterokinase activity by release of radiolabelled activation peptides from alpha-N-[3H]acetyl-trypsinogen and the effect of calcium ions on the enzyme activity.

We report a novel assay method for enterokinase capable of detecting approx. 1 fmol of enzyme. The method depends on quantification of the release of specifically radiolabelled activation peptides from bovine trypsinogen and is unaffected by trypsin inhibitors. The assay is applicable to biological fluids such as serum. The substrate was produced by selective epsilon-amidination of bovine trypsinogen followed by acetylation with [3H]acetic anhydride and deprotection. The assay has been used to study the effects of pH, Ca2+, ionic strength abd glycodeoxycholate on enterokinase activity.

Acetylation↗
PubMed1998

Leukocyte-endothelial adherence correlates with pancreatic nitric oxide production in early cerulein-induced pancreatitis in rats.

The role of nitric oxide (NO) in microcirculation during the development of acute pancreatitis was not clear. An in vivo microscopic technique was used for evaluating leukocyte-endothelial adherence in the pancreatic microcirculation after induction (cerulein) of acute pancreatitis. Microdialysis was performed to detect pancreatic nitrate concentration (NO level) by high-performance liquid chromatography. Cerulein caused significantly reduced flow velocity in 1 h (31 %) and increased the number of sticking leukocytes in 2 h; both persisted for at least 3 h. Pancreatic NO level was found to be significantly elevated (2.5-fold) in 1 h and also persisted for 3 h. Both microcirculatory changes and NO elevation were significantly alleviated in cerulein-induced animals pretreated with NO synthase inhibitor (NG-nitro-L-arginine), indicating that elevation of NO could precede and account for a major portion of the observed microcirculatory changes. Furthermore, there was a strong positive correlation between numbers of adherent leukocytes and pancreatic NO level, suggesting that during the development of acute pancreatitis, NO could play an adverse role in microcirculation.

Animals↗
PubMed2006

Characterization of fasted-state human intestinal fluids collected from duodenum and jejunum.

The solubility of drugs in the gastrointestinal tract is very challenging to simulate with artificial media due to the high complexity of human intestinal fluid (HIF). In particular, bile salt composition, pH and buffer capacity are very important characteristics of HIF, since they determine the solubility of drugs in-vivo. In this study, we have measured the concentrations of individual bile salts in human intestinal fluids (n=6) collected from two different locations (duodenum and jejunum) in the fasted state. Total bile salt concentrations ranged from 570 to 5,137 microM in the duodenum and from 829 to 5,470 microM in the jejunum. The following rank order of relative bile salt concentration in duodenum was observed: taurocholic acid > glycocholate >or= glycochenodeoxycholate > glycodeoxycholate > taurochenodeoxycholate > taurodeoxycholate. Cholic acid, tauroursodeoxycholate, chenodeoxycholic acid, and deoxycholic acid represented less than 1% of bile salts present in the samples. Ursodeoxycholate could not be detected in HIF. No statistically significant difference between bile salt composition of duodenal and jejunal aspirates was observed. The buffer capacity of HIF was compared with other media commonly used for solubility/dissolution determinations, indicating a relatively low buffer capacity of HIF (4-13 mmol L(-1)/pH). This low buffer capacity was reflected in the change in pH (between 4 and 9.5) that occurred in HIF after addition of model compounds covering a broad pK(a) range. Interindividual variability in pH, buffer capacity and bile salt contents of HIF will contribute to differences in the rate and extent of absorption of compounds for which dissolution/solubility is the rate limiting step. The variability observed warrants further research to explore the impact of intraluminal conditions on drug solubility.

Adult↗
PubMed2000

Rat hepatocellular apoptosis induced by glycodeoxycholate.

OBJECTIVE: To explore the relationship between glycodeoxycholate (GDC) and rat hepatocellular apoptosis. METHODS: GDC was used to treat rat hepatocytes cultured in vitro and the apoptotic cells were observed and analyzed with light microscope, transmission electron microscope, TUNEL in situ hybridization, DNA agarose gel electrophoresis and flow cytometry. RESULTS: When rat hepatocytes were incubated with GDC (final concentration of 100 micromol/L) for 2h, apoptotic hepatocytes were observed with light and transmission electron microscope, and TUNEL in situ hybridization. When the hepatocytes were incubated with GDC (final concentration of 50, 100, 150 micromol/L, respectively) for 2h, or with GDC (final concentration of 100 micromol/L) for 2, 4, 6, 8h, respectively, agarose gel electrophoresis of the hepatocytes DNA demonstrated the typical ladder patterns. CONCLUSION: GDC with final concentration of 50, 100, 150 micromol/L could induce rat hepatocellular apoptosis.

Animals↗
PubMed1982

Solubilization and characterization of active opiate binding sites from mammalian brain.

Active binding sites have been solubilized from cell membranes derived from mammalian brain. High affinity, stereospecific binding to soluble sites was demonstrable when membranes from rat brain, human frontal cortex and bovine corpus striatum were treated with digitonin or glycodeoxycholate, provided that the binding assay was conducted at 25 degrees C or below and in the presence of 50 to 100 mM NaCl. The yield of solubilized binding sites extracted from brain cell membranes was increased substantially (up to 43% yield from bovine striatum) when membranes were treated with detergent solutions containing 0.5 to 1.0 M NaCl. This effect was not observed when LiCl, KCl or (NH4)2SO4 were substituted for NaCl. Evidence for the solubility of the binding sites was provided by two criteria: nonsedimentation after 2 hr of centrifugation at 10(5) X g and an apparent molecular weight of 3 to 4 X 10(5) as determined by gel filtration.

Animals↗