Galactose solution

Other than the absorption at 1718 cm", the freeze-dried material from equilibrated solutions of D-mannose, D-glucose, and L-rhamnose shows only the absorptions characteristic of the respective, crystalline a- and 8-pyranose forms. The lyophilizate of D-galactose solution showed similar behavior, except for an absorption band at 921 cm". The lyophilizates of equilibrated solutions of D-lyxose and D-talose show a number of absorption bands not found in the spectra for the crystalline anomeric pairs. ... 

Method The principle of GEC involves the intravenous administration of galactose in excess substrate in order to assess the maximum rate of hepatic metabolization. This requires a galactose concentration of 0.5 g/kg BW (serum concentration of > 45 mg/dl for at least 45 minutes), which is injected within 4—5 minutes as a 40% pyrogen-free sterile galactose solution. The bladder has to be emptied immediately prior to the injection and subsequently the urine has to be collected for exactly 5 hours to assess the respective galactose excretion (in grams). Blood samples are taken from the fingertip (or from the cubital vein into an EDTA test tube) at 5, 25 and 45 minutes after injection. We have reported in detail on how to conduct this method as well as on the analysis of GEC. (67, 69)... 

The use of signal amplification with the help of ultrasound contrast medium provides a considerably improved depiction of portohepatic vessels as well as the perfusion of hepatic tumours. Microbubbles are used as a contrast medium. The echo signal is amplified by increased back-scattering of ultrasound waves caused by the microbubbles. This technique is based on observations made by the cardiologist C.R. Joyner, jr. (1966). Up to now, the medium of choice has been a galactose solution (99.9%) suspended in palmitic acid, the latter being used to stabilize the microbubbles. It is administered as a bolus injection or intravenously. (17,100)... 

Assay. The standard assay mixture for determination of the activator consists of 1 nmol ganglioside Gmi, [ H]-labeled in the terminal galactose moiety ( 100,000 cpm), 5 mU p-galactosidase and up to 25 p,l of the suitably diluted activator sample, in a total volume of 50 jil of 50 mM citrate buffer, pH 4.5. The assays are incubated for 1 h at 37°C and then transferred to an ice-bath, and 1 ml of an ice-cold 1 mM galactose solution is added. The mixtures are loaded onto small (0.5—1 ml) columns of DEAE-cellulose (in Pasteur pipettes) that have been washed with distilled water. Liberated [ HJgalactose is washed out with 2 x 1 ml of 1 mM aqueous galactose solution, the combined effluents are collected in scintillation vials, and, after addition of 10 ml of scintillation fluid, their radioactivity is measured in a liquid scintillation counter. Blanks run with water instead of activator solution are subtracted. 

Continuous hydrolysis of galactose is attempted by passing galactose solution through the column where aminated fiber, to which P-galactosidase firom the typhoid bacillus is fixed, is packed. After 12 days, there were few problems other than the plugging of the column. During the entire period, the flow rate was nearly constant and there was no sudden decrease in activity. The half-life was approximately one month [13]. 

The weights of other monosaccharides and reducing disaccharides which will reduce i ml. of this standard Fehling s solution are galactose, 0 00511 g- fructose. 0 00514 g.. mannose, 0 00431 g. lactose, 0 00678 g. maltose, 0 00807 g. 

The approximate times of osazone formation in minutes are given in Table 111,139. The product from mannose is the simple hydrazone and is practically white. Arabinose osazone separates first as an oil, whilst that from galactose is highly crystalline. Lactose and maltose give no precipitate from hot solution. 

Oxidation of galactose (or a galactose-containing sugar) to mucic acid. Dissolve 1 g. of galactose or lactose in a mixture of 10 ml. of water and 5 ml. of concentrated nitric acid contained in a small evaporating dish, and evaporate the solution to dryness on a water bath. Stir the cold residue with 10 ml. of cold water, filter off the mucic acid, wash it with cold water, dry and determine the m.p. (212-213° with decomposition). 

Gum ghatti is the calcium and magnesium salt of a complex polysaccharide which contains L-arabinose, D-galactose, D-mannose, and D-xylose and D-glucuronic acid (48) and has a molecular weight of approximately 12,000. On dispersion in water, gum ghatti forms viscous solutions of viscosity intermediate between those of gum arabic and gum karaya. These dispersions have emulsification and adhesive properties equivalent to or superior to those described for gum arabic. 

Sucralose is quite stable to heat over a wide range of pH. However, the pure white dry powder, when stored at high temperature, can discolor owing to release of small quantities of HCl. This can be remedied by blending it with maltodextrin (93) and other diluents. The commercial product can be a powder or a 25% concentrate in water, buffered at pH 4.4. The latter solution may be stored for up to one year at 40°C. At lower pH, there is minimal decomposition. For example, in a pH 3.0 cola carbonated soft drink stored at 40°C, there is less than 10% decomposition after six months. The degradation products are reported to be the respective chlorinated monosaccharides, 4-chloro-4-deoxy-galactose (13) and l,6-dichloro-l,6-dideoxy-fmctose (14) (94). 

The energy substrates are contraindicated in patients with hypersensitivity to any component of the solution. Dextrose solutions are contraindicated in patients with diabetic coma with excessively high blood sugar. Concentrated dextrose solutions are contraindicated in patients with increased intracranial pressure, delirium tremens (if patient is dehydrated), hepatic coma, or glucose-galactose malabsorption syndrome Alcohol dextrose solutions are contraindicated in patients with epilepsy, urinary tract infections, alcoholism, and diabetic coma... 

FIGURE 4-15 Cyclic voltanmiograms for 1.5 x 10 3 M ribose (a), glucose (b), galactose (c), and fructose (d) recorded at a Ru02-modified carbon-paste electrode. Dotted lines were obtained in carbohydrate-free solutions. (Reproduced with permission from reference 50.)... 

A number of complexes of copper with 1,1-dithiolenes are known they are interesting, inasmuch as they form (1) polynuclear species, e.g., [Cu4(i-mnt)3]2 . Recently, a copper(III) complex of 1,1-dicarboeth-oxy-2-ethylenedithiolate (DED ) was prepared (375) by oxidation of aqueous solutions of K2[Cu(DED)2] with a 10-15% excess of Cu(II) or H202, and of (BzPh3P)2[Cu(DED)2] with I2. The possibility of this system as a model for the Cu "/Cu. system in n-galactose oxidase has been pointed out. Lewis and Miller (113) also prepared M[Cu(S2C CHN02)2] (M = Cu, or Zn) and Cu[Cu S2C C(CN)2 2], and found that they are effective insecticides. 

The a anomers of 2-acetamido-2-deoxy-D-glucose and 2-acetamido-2-deoxy-D-galactose have the same nir c.d. bands in 1 1 methanol-water at 0° as the anomeric mixtures have in aqueous solution. This indicates that the anomeric configuration has little influence on the nir c.d. band. 

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