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Biomedical subjects

G B Phillips

Publications and source records attributed to G B Phillips.

At least 73 records · Page 4Linked to original sources
PubMed1968

Analysis of fatty acids of human red cells without lipid extraction.

Exposure of human red cells to 2 N HCl for 18-20 hr at 110 degrees C appears to release the total fatty acid, which can then be esterified for GLC analysis. This technique is simpler and may be more reliable than the conventional methods that depend on lipid extraction of the red cells.

Chromatography, Gas↗
PubMed1967

Laboratory design for microbiological safety.

Of the large amount of funds spent each year in this country on construction and remodeling of biomedical research facilities, a significant portion is directed to laboratories handling infectious microorganisms. This paper is intended for the scientific administrators, architects, and engineers concerned with the design of new microbiological facilities. It develops and explains the concept of primary and secondary barriers for the containment of microorganisms. The basic objectives of a microbiological research laboratory, (i) protection of the experimenter and staff, (ii) protection of the surrounding community, and (iii) maintenance of experimental validity, are defined. In the design of a new infectious-disease research laboratory, early identification should be made of the five functional zones of the facility and their relation to each other. The following five zones and design criteria applicable to each are discussed: clean and transition, research area, animal holding and research area, laboratory support, engineering support. The magnitude of equipment and design criteria which are necessary to integrate these five zones into an efficient and safe facility are delineated.

Animals↗
PubMed1967

Peroxidative hemolysis of red blood cells from patients with abetalipoproteinemia (acanthocytosis).

The effect of peroxidative stress on tissue was studied by exposure of red blood cells (RBC) from patients with abetalipoproteinemia to minute amounts of H(2)O(2)in vitro. Red blood cells from untreated patients showed a marked sensitivity to H(2)O(2), as evidenced by hemolysis and lipid peroxidation (peroxidative hemolysis). The appearance of lipid peroxidation products in sensitive cells after exposure to H(2)O(2) was indicated by 1) increases in the 2-thiobarbituric acid (TBA) reaction of trichloroacetic acid extracts, 2) increases in ultraviolet light absorbency of lipid extracts, and 3) decreases in polyunsaturated fatty acids. These changes were accompanied by a decrease in phosphatidyl ethanolamine and phosphatidyl serine in the RBC lipid extract. Similar lipid changes on exposure to H(2)O(2) were observed in the RBC from vitamin E-deficient rats. Treatment of the patients with d-alpha-tocopherol polyethylene glycol succinate by mouth, or addition of dl-alpha-tocopherol to the incubation medium protected the RBC from peroxidative hemolysis. Tocopherol appears to provide a primary biologic defense against peroxidative hemolysis. The presence of nitrite or carbon monoxide, which produced methemoglobin and carboxyhemoglobin, respectively, inhibited peroxidative changes, suggesting a catalytic role for oxy- or deoxyhemoglobin. Substances that prevented lipid peroxidation also prevented hemolysis; in addition, lipid peroxidation appeared to precede hemolysis. These observations suggested that hemolysis was a consequence of lipid peroxidation.

Abetalipoproteinemia↗
PubMed1967

Composition of phospholipids and of phospholipid fatty acids and aldehydes in human red cells.

Improved methods for lipid analysis that have been developed recently were employed to reevaluate the phospholipid composition, the fatty acid and fatty aldehyde composition of the total phospholipid, and the fatty acid composition of the individual phospholipids of normal human red cells. Thirty-three fatty acids and five fatty aldehydes were estimated and tentatively identified in the total phospholipid of normal human red cells. Additional minor components were evident. The major individual phospholipids were isolated by silicic acid thin-layer chromatography and quantified. The fatty acid compositions of phosphatidyl ethanolamine, phosphatidyl serine, lecithin, and sphingomyelin were determined. Each of these phospholipids showed a distinctive and characteristic fatty acid pattern.

Adult↗
PubMed1967

Composition of phospholipids and of phospholipid fatty acids of human plasma.

The composition of the phospholipids and of the total phospholipid fatty acids was determined in the plasma of 10 normal subjects. In addition the fatty acid composition of the plasma phosphatidyl ethanolamine, phosphatidyl serine, lecithin, sphingomyelin, and lysolecithin of 6 of the subjects was measured. A wide array of fatty acids was found in the plasma total phospholipid similar to that found previously in red cell total phospholipid. The fatty acid composition in the plasma phospholipids of a given subject reflected that in his red cell phospholipids. Each individual phospholipid displayed a distinctive fatty acid pattern, which was generally similar to that of the corresponding phospholipid of red cells, although some marked differences in individual fatty acid levels between the corresponding phospholipids of plasma and red cells were evident. The high percentage of unsaturated fatty acids found in plasma lysolecithin suggests that this phospholipid did not arise entirely through the enzymatic cleavage of the -fatty acid of lecithin.

Adult↗
PubMed1966

Autoxidation as a cause of altered lipid distribution in extracts from human red cells.

A characteristic alteration in the distribution of human red cell phospholipids represents an artifact due to autoxidation of the lipid extract. This alteration is manifested on silicic acid chromatography by a decrease mainly in the phosphatidyl ethanolamine and phosphatidyl serine fractions (probably because of their abundance of highly unsaturated fatty acids) and an increase in the phospholipid recovered with the more polar fractions, sphingomyelin and lysolecithin. No evidence was found for "lysocephalin" formation or plasmalogen breakdown in dry lipid extracts after autoxidation by exposure to air at room temperature for 24-35 hr. On thin-layer chromatography, however, the ninhydrin-positive streaking in the autoxidized samples may be erroneously attributed to the presence of "lyso" derivatives. When the alterations in lipid distribution described above are found, the possibility of this artifact should be considered.

Chromatography, Gas↗