Large-field trichromacy in protanopes and deuteranopes.

Protanopes and deuteranopes do not accept the classical dichromatic matches when field size extends to 8 degrees visual angle. Their unique matches of spectral yellow to a mixture of red and green are then mediated by the photoreceptors of small-field dichromacy interacting with a photoreceptor with the spectral sensitivity of rhodopsin. Our data suggest that large-field trichromacy is a general feature of protanopia and deuteranopia.

Volatile degradation products of l-dehydroascorbic acid.

Volatile degradation products were isolated from a solution of L-dehydroascorbic acid in phosphate buffer solution of pH 2,4,6 and 8 heated under reflux for 3 h or left at 25 degrees C for 200 h. The products were identified by comparison of their gas chromatographic retention data, infra-red and mass spectra with those of authentic compounds. Fifteen products were identified, among which 12 had not yet been reported as degradation products of L-dehydroascorbic acid.

Effect of field size on red--green color mixture equations.

Red-green color mixture equations were measured in 10 color-normal observers for fields of view varying from 30' to 10 degrees. The G/R mixture decreases continuously as field size is increased. The data are consistent with the interpretation that the cone visual photopigments decrease exponentially in effective optical density as the field size is increased.

Comparison of chromatographic methods for the analysis of glycerol esters.

Column, thin-layer and gel chromatography have been compared as methods for the analysis of glycerol esters. It was found that gel chromatography gave much easier and faster analyses of monoglyceride emulsifiers, while at the same time providing a satisfactory distribution of fractions and giving an accuracy of determination corresponding to that of the standard method for their analysis.

Lipid oxidation. Part 4. Products of thermooxidative polymerization of vegetable oils.

The thermal treatment of vegetable oils was studied by gel chromatography on packings of styrene-divinylbenzene copolymers. Unlike oils with a lower content of polyene acids, those with a high content of polyene acids contained a larger amount of higher oligomers of fatty acids. The gel chromatography of fatty acid methyl esters from heated oils allowed the determination of the ratio of intra- and intermolecular bonds arising by polymerization reactions.

Lipid oxidation. Part 3. Oxidation of egg phosphatidylethanolamine.

Phosphatidylamine isolated from egg yolk phospholipids was autoxidized at 60 degrees C. Oxidation products were separated by thin layer chromatography on silica gel and by column chromatography of DEAE-cellulose. The fractions were characterized by UV and IR spectra and by chemical analysis.

Nonenzymic browning. XV. Effect of unsaturation on browning reactions of oxidized lipids with protein.

The amount of pigments produced by interaction of oxidized lipids with albumin and the intensity of coloration increase with increasing degree of unsaturation of the lipid fraction.

Reactions of oxidized lipids with protein. XIII. Interactions of polar groups of lipids with nonlipidic substances.

Contrary to fresh lipids, oxidized lipids form chloroform-insoluble, but methanol-soluble compounds with cellulose. The amount of chloroform-insoluble lipids is significantly higher in mixtures containing cellulose impregnated with albumin. Polar groups of oxidized lipids formed nonextractable compounds with protein more readily than polar groups of a monoglyceride.

[Development of fish flavor by reaction of autoxidized lipids with amino acids and proteins].

The rancid fish-oil flavour of autoxidized tetraene, pentaene and hexaene fatty acid esters disappears during storage or heating with free amino acids or proteins. Simultaneously, a flavour of raw, roasted or fried fish develops. The development of this fish flavour is of particular intensity in mixtures containing lysine or some other amino acids.

Changes of sensory value by interaction of alkanals with amino acids and proteins.

Alkanals as carriers of rancid flavour of fat-containing foods were stored in mixtures with nonlipidic substances. The intensity of odour due to alkanals decreased with increasing time of storage, the changes being more pronounced in case of casein than in that of cellulose. Results of sensory tests did not depend on the molecular mass of aldehyde.

Lipid oxidation. Part 2. Oxidation products of olive oil methyl esters.

Olive oil was converted into methyl esters which were autoxidized at 60 degrees C. The composition of oxidized products was determined by the comparison of infrared spectra and NMR spectra of the original and acetylated samples, the sample reduced with potassium iodide and the acetylated reduced sample. Oxidized products were separated by preparative thin layer chromatography on silica gel and characterized by selective detection and by infrared spectrometry of the fractions.

Lipid oxidation. Part. 1. Effect of free carboxyl group on the decomposition of lipid hydroperoxide.

Hydroperoxido butyl oleate was decomposed by heating in excess palmitic acid at 60-120 degrees C. The decomposition followed the kinetics of a first order reaction with formation of both monomeric and oligomeric secondary products. The proportions of oligomers slightly increased with increasing reaction temperature and decreased with increasing concentration of hydroperoxide.

Incidence of ischaemic heart disease and prognostic importance of risk factors in agricultural and industrial populations.

A longitudinal epidemiological study of ischaemic heart disease (IHD) in men aged 40-59 years showed that the five-year incidence of the manifest form was 7.8% in agricultural workers and 9.7% in industrial employees.

Nonenzymic browning. XIV. Reaction of phospholipids with 1,4-benzoquinone.

Phosphatidylethanolamine reacts with 1,4-benzoquinone with the formation of a red unstable intermediary product consisting of one phosphatidylethanolamine residue and one 1,4-benzoquinone residue. The secondary reaction products are purple, violet, and reddish brown. Consequently, the absorption maximum shifts from 430 nm to 490 nm during the reaction.