Enzymic colorimetric determination of phosphatidylglycerol in amniotic fluid.

1984 ◽  
Vol 30 (4) ◽  
pp. 534-537 ◽  
Author(s):  
J D Artiss ◽  
M W McGowan ◽  
D R Strandbergh ◽  
E Epstein ◽  
B Zak
Keyword(s):  
Amniotic Fluid ◽  
Fetal Lung ◽  
Aqueous Sample ◽  
Colorimetric Determination ◽  
Glycerol Phosphate ◽  
Ionic Detergent ◽  
Catalyzed Reactions ◽  
Enzyme Catalyzed Reactions ◽  
Hydrolysis Of

Abstract We describe a procedure for the enzymic, colorimetric determination of phosphatidylglycerol in amniotic fluid. After extraction into chloroform:methanol (2:1 by vol) and evaporation, the phospholipid-containing residue is redissolved in a non-ionic detergent, which thus provides an aqueous sample. The subsequent enzymic reaction sequence involves phospholipase-catalyzed hydrolysis of glycerol from its phospholipid. Subsequent enzyme-catalyzed reactions phosphorylate this glycerol and oxidize the resulting glycerol phosphate to produce hydrogen peroxide, which is reacted to produce an intense red chromogen in the peroxidase-catalyzed coupling of 4-aminoantipyrine and 2-hydroxy-3,5-dichlorobenzenesulfonate. When used in conjunction with previously reported enzymic techniques for determination of lecithin and sphingomyelin, this procedure may provide an accurate and precise "lung profile" for assessment of fetal lung maturity.

Enzymatic colorimetry of lecithin and sphingomyelin in aqueous solution.

1983 ◽  
Vol 29 (8) ◽  
pp. 1513-1517 ◽  
Author(s):  
M W McGowan ◽  
J D Artiss ◽  
B Zak
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Amniotic Fluid ◽  
Enzymatic Reaction ◽  
Detergent Solution ◽  
Enzymatic Determination ◽  
Red Color ◽  
Hydrolysis Of ◽  
Zwitterionic Detergent

Abstract A procedure for the enzymatic determination of lecithin and sphingomyelin in aqueous solution is described. The phospholipids are first dissolved in chloroform:methanol (2:1 by vol), the solvent is evaporated, and the residue is redissolved in an aqueous zwitterionic detergent solution. The enzymatic reaction sequences of both assays involve hydrolysis of the phospholipids to produce choline, which is then oxidized to betaine, thus generating hydrogen peroxide. The hydrogen peroxide is subsequently utilized in the enzymatic coupling of 4-aminoantipyrine and sodium 2-hydroxy-3,5-dichlorobenzenesulfonate, an intensely red color being formed. The presence of a non-reacting phospholipid enhances the hydrolysis of the reacting phospholipid. Thus we added lecithin to the sphingomyelin standards and sphingomyelin to the lecithin standards. This precise procedure may be applicable to determination of lecithin and sphingomyelin in amniotic fluid.

Rapid determination of fetal lung maturity from infrared spectra of amniotic fluid

1998 ◽  
Vol 178 (2) ◽  
pp. 234-241 ◽  
Author(s):  
Kan-Zhi Liu ◽  
Thomas C. Dembinski ◽  
Henry H. Mantsch
Keyword(s):  
Amniotic Fluid ◽  
Infrared Spectra ◽  
Rapid Determination ◽  
Fetal Lung ◽  
Fetal Lung Maturity ◽  
Lung Maturity

Determination of Sevin Insecticide Residues in Fruits and Vegetables

1964 ◽  
Vol 47 (2) ◽  
pp. 283-286
Author(s):  
D P Johnson
Keyword(s):  
Fruits And Vegetables ◽  
Collaborative Study ◽  
Colorimetric Determination ◽  
Average Recovery ◽  
Insecticide Residues ◽  
Chromogenic Agent ◽  
Hydrolysis Of ◽  
Concentration Levels ◽  
Good Agreement

Abstract Collaborative study of a method for Sevin insecticide residues was repeated with apples and lettuce as test crops. The method is based on alkaline hydrolysis of Sevin and colorimetric determination of the resulting 1-naphthol with p-nitrobenzenediazonium fluoborate as chromogenic agent. Data from 5 collaborators were in good agreement with an average recovery of 87.8% at 2 concentration levels. It is recommended that the method be adopted as official, first action.

Radial "high-performance" thin-layer chromatography used to assess fetal lung maturity

1990 ◽  
Vol 36 (5) ◽  
pp. 728-731 ◽  
Author(s):  
J R Mackenzie ◽  
M Truesdale
Keyword(s):  
Thin Layer ◽  
Amniotic Fluid ◽  
Thin Layer Chromatography ◽  
High Performance ◽  
Fetal Lung ◽  
Additional Method ◽  
Layer Chromatography ◽  
Hptlc Method ◽  
Lung Maturity

Abstract A radial "high-performance" thin-layer chromatographic (HPTLC) method is described by which the percentages and ratios of phosphatidylinositol, sphingomyelin, lecithin, phosphatidylethanolamine, phosphatidylglycerol, and dimethyl phosphatidylethanolamine may be determined simultaneously. An additional method for radial HPTLC determination of saturated phosphatidylcholine is described. We report results of application of these methods to greater than 2000 specimens of amniotic fluid from both diabetic and nondiabetic cases.

An Automated Alkaline Phosphatase Assay with Phenolphthalein Monophosphate as Substrate

1967 ◽  
Vol 13 (4) ◽  
pp. 281-289 ◽  
Author(s):  
Kirsten Hviid
Keyword(s):  
Alkaline Phosphatase ◽  
Normal Values ◽  
Serum Alkaline Phosphatase ◽  
Colorimetric Determination ◽  
Alkaline Phosphatase Assay ◽  
Phosphatase Assay ◽  
Hydrolysis Of

Abstract The manual procedure of Babson et al. (1) for the determination of serum alkaline phosphatase has been automated. The assay is based on the colorimetric determination of phenolphthalein formed on hydrolysis of phenolphthalein monophosphate. The procedure utilizes 0.16 ml. of serum without dialysis. Blanks are required only for turbid sera. Results are compared with those obtained by the manual procedure, and data relating to sample interaction, precision, blank values, and normal values are presented.

THE PATTERN OF URINARY EXCRETION OF INDIVIDUAL 17-KETOSTEROIDS IN RHESUS MONKEYS

1971 ◽  
Vol 67 (4) ◽  
pp. 711-720 ◽  
Author(s):  
S. B. Pal
Keyword(s):  
Rhesus Monkeys ◽  
Enzyme Hydrolysis ◽  
Colorimetric Determination ◽  
Day Range ◽  
Extraction Separation ◽  
Normal Mean ◽  
The Individual ◽  
Hydrolysis Of ◽  
Steroid Conjugates

ABSTRACT A systematic procedure for the extraction, separation, purification and colorimetric determination of urinary individual 17-ketosteroids in normal rhesus monkeys is described. Dehydroepiandrosterone was extracted after hot hydrolysis of the urine at neutral pH and the remaining steroid conjugates were extracted at pH 2 by the addition of ammonium sulphate. The liberated steroids were extracted after enzyme hydrolysis and the ketonic steroids were separated from the non-ketones by the Girard T reaction. The 11-deoxy steroids were separated from the 11-oxygenated steroids on a Celite column. They were further separated by paper chromatography and after elution, the individual 17-ketosteroids were estimated by the Zimmermann reaction. Normal mean excretion values in 30 female monkeys for total neutral 17-ketosteroids were 1.8 mg/24 h (range 1.5–2.6); total 17-hydroxycorticosteroids, 3.1 mg/24 h (range 2.2–4.8); androsterone, 38.6 μg/kg/24 h (range 9.3–60.2); aetiocholanolone, 19.2 μg/kg/24 h (range 6.8–30.7); dehydroepiandrosterone, 30.8 μg/kg/24 h (range 13.4–50.6); 11-ketoandrosterone, 7.5 μg/kg/24 h (range 5.1–14.1); 11-ketoaetiocholanolone, 10.2 μg/kg/24 h (range 6.8–18.3); 11β-hydroxyandrosterone, 15.4 μg/kg/24 h (range 8.8–26.7); 11β-hydroxyaetiocholanolone, 19.6 μg/kg/24 h (range 12.2–33.1). For total neutral 17-ketosteroids in 20 males, they were 2.5 mg/day (range 2.3–4.1); total 17-hydroxycorticosteroids, 3.7 mg/day (range 2.8–5.3); androsterone, 51.5 μg/kg/24 h (range 12.3–76.7); aetiocholanolone, 22.6 μg/kg/24 h (range 8.7–42.3); dehydroepiandrosterone, 41.3 μg/kg/24 h (range 16.9–59.7); 11-ketoandrosterone, 9.6 μg/kg/24 h (range 6.4–16.3); 11-ketoaetiocholanolone, 12.3 μg/kg/24 h (range 8.2–20.5); 11β-hydroxyandrosterone, 17.5 μg/kg/24 h (range 11.7–29.2); 11β-hydroxyaetiocholanolone, 21.7 μg/kg/24 h (range 14.5–36.4).

Steady-State Kinetics of Enzyme Reactions in the Presence of Added Nucleophiles

1972 ◽  
Vol 50 (12) ◽  
pp. 1334-1359 ◽  
Author(s):  
Irwin Hinberg ◽  
Keith J. Laidler
Keyword(s):  
Specific Binding ◽  
Specific Binding Sites ◽  
Steady State Kinetics ◽  
Special Cases ◽  
Kinetics Of Formation ◽  
Catalyzed Reactions ◽  
Enzyme Catalyzed Reactions ◽  
Concentration Graphs ◽  
Kinetics Of ◽  
Hydrolysis Of

Many enzyme-catalyzed reactions, such as hydrolyses, give rise to two products P1 and P2 which are formed in different reaction steps. The second product P2 is frequently formed by hydrolysis of an intermediate such as an acyl-enzyme or a phosphoryl-enzyme. An alternative nucleophile N introduced into the system forms an additional product P3. The present paper is concerned with the kinetics of formation of P1, P2, and P3 in the presence of added nucleophiles. A number of alternative mechanisms are considered, and equations are derived for the rates of formation of the three products, and the Michaelis constant, as functions of nucleophile concentration. Graphs are presented showing the variations of these parameters with the concentration of N, for a variety of special cases. Special attention is given to the possibility of specific binding sites for the water and the nucleophile molecules.The data for a number of enzyme systems are discussed with reference to the treatment. For reactions catalyzed by alkaline phosphatase it is concluded that only one mechanism (mechanism VI) is consistent with the results.

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