Subject(s)
Blood Volume/drug effects , Colloids/therapeutic use , Hydroxyethyl Starch Derivatives/therapeutic use , Plasma Substitutes/therapeutic use , Chemical Phenomena , Chemistry, Physical , Colloids/adverse effects , Colloids/chemistry , Humans , Hydroxyethyl Starch Derivatives/adverse effects , Hydroxyethyl Starch Derivatives/chemistry , Plasma Substitutes/adverse effects , Plasma Substitutes/chemistryABSTRACT
The structure of sinistrin from red squill (Urginea maritima) was determined by methylation analysis and 13C NMR spectroscopy, using the fructans from Pucinella peisonis and quack-grass (Agropyron repens) as reference substances. Application of the reductive cleavage method showed that, of the beta-D-fructofuranosyl residues in sinistrin, 33% were 1-linked, 19% were 6-linked, 25% were terminal, and 19% were 1,6-linked. The average dp was 31 and, of the 3.24% of alpha-D-glucopyranosyl residues, 0.54% were terminal and 2.70% were 6-substituted. The fructan of quack grass was also highly branched with a (2-->6)-linked backbone, terminal alpha-D-glucopyranosyl residues, and a dp of approximately 45. The fructan from Pucinella peisonis was slightly branched, with a dp of approximately 10 and a (2-->6)-linked backbone.
Subject(s)
Oligosaccharides/chemistry , Plants/chemistry , Carbohydrate Conformation , Carbohydrate Sequence , Carbon Isotopes , Glucose/analysis , Indicators and Reagents , Magnetic Resonance Spectroscopy/methods , Methylation , Molecular Sequence Data , Oligosaccharides/isolation & purificationABSTRACT
The 13C CPMAS n.m.r. spectrum of 4-O-beta-D-galactopyranosyl-D-fructose (lactulose) trihydrate, C12H22O11.3 H2O, identifies the isomer in the crystals as the beta-furanose. This is confirmed by a crystal structure analysis, using CuK alpha X-ray data at room temperature. The space group is P212121, with Z = 4 and cell dimensions a = 9.6251(3), b = 12.8096(3), c = 17.7563(4) A. The structure was refined to R = 0.031 and Rw 0.025 for 1929 observed structure amplitudes. All the hydrogen atoms were unambigously located on difference syntheses. The conformation of the pyranose ring is the normal 4C1 chair and that of the furanose ring is 4T3. The 1----4 linkage torsion angles are O-5'-C-1'-O-1'-C-4 = 79.9(2) degrees and C-1'-O-1'-C-4-C-5 = -170.3(2) degrees. All hydroxyls, ring and glycosidic oxygens, and water molecules are involved in the hydrogen bonding, which consists of infinite chains linked together by water molecules to form a three-dimensional network. There is a three-centered intramolecular, interresidue hydrogen bond from O-3-H to O-5' and O-6'. The n.m.r. spectrum of the amorphous, dehydrated trihydrate suggests the occurrence of a solid-state reaction forming the same isomeric mixture as was observed in crystalline anhydrous lactulose, although the mutarotation of the trihydrate when dissolved in Me2SO is very slow.
Subject(s)
Lactulose/chemistry , Carbohydrate Conformation , Carbohydrate Sequence , Crystallography , Hydrogen Bonding , Isomerism , Magnetic Resonance Spectroscopy , Models, Molecular , Molecular Sequence Data , Water/chemistryABSTRACT
The recent developed thin-layer electrophoresis on modified silanized silica gel was applied to the separation of hydroxyethyl starches (HES) and glycogen and of HES with different degrees of substitution. This method permits a rapid qualitative and semi-quantitative determination of HES in animal tissues such as liver, lung, heart and kidney after their disintegration with alkali and precipitation with ethanol.
Subject(s)
Electrophoresis/methods , Hydroxyethyl Starch Derivatives/metabolism , Animals , Glycogen/chemistry , Humans , Hydroxyethyl Starch Derivatives/blood , Lung/chemistry , Myocardium/chemistry , Rabbits , Silica Gel , Silicon Dioxide/chemistry , TemperatureABSTRACT
Two commercially available hydroxyethyl starch (HES) preparations (in clinical use as plasma expanders) specified with Mw = 450,000/MS = 0.7 and Mw = 200,000/MS = 0.5, respectively, and three experimental HES-samples (supposingly similar to the commercial product with the specification 450,000/0.7, except of one with MS = 0.5) were studied. The latter were prepared via acid or enzymatic hydrolysis of waxy-maize starch. Each of the samples was characterized by its intrinsic viscosity and molar substitution, and was studied with low-angle laser light scattering (LALLS) and with size exclusion chromatography (SEC) coupled with LALLS. The weight-average molecular weight Mw of the commercial samples was found to be 60-80% higher than the value given in the product declaration. This discrepancy can be explained by the argument that previous measurements were not carried out at sufficiently small scattering angles to enable reliable extrapolation to zero angle. The calibration functions Mw(v) of the individual HES-samples measured by SEC/LALLS-coupling are identical over a broad range of the elution volume v and are used for calibration of conventional SEC in a subsequent paper. The small, but detectable differences in the Mw(v)-functions indicate interesting differences between these HES-preparations with respect to the effective hydrodynamic density of the branched HES-molecules.
Subject(s)
Hydroxyethyl Starch Derivatives/analysis , Starch/analogs & derivatives , Chromatography, Gel , Light , Molecular Weight , Scattering, Radiation , ViscosityABSTRACT
32 volunteers, none of whom showed any symptoms for kidney, liver or pancreas disease, were given by infusion 500 ml of various type of hydroxyethyl starch (HES) at a concentration of 6% (450/0.7, 450/0.5, 450/0.3, 300/0.4) as well as of 10% (200/0.7, 200/0.5, 200/0.3, 200/0.1) over a period of 30 min. After infusion both the Mw and the Mn diminished. The rate of elimination of HES from serum entirely depended on molar substitution and not on Mw. The quotient Mw/Mn decreased considerably over the entire test period. The lower molecular weight limit in serum remained relatively the same at 60,000 Daltons. Maximum molecular weight limit of urine, too, was 60,000 Daltons.
