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Biomedical subjects

G M Gray

Publications and source records attributed to G M Gray.

At least 91 records · Page 5Linked to original sources
PubMed1975

Mitochondria and nuclei of pig and human epidermis: isolation and lipid composition.

Pig and human epidermis were mechanically disrupted with a Polytron homogenizer and mitochondria and nuclei were isolated from homogenates in buffered sucrose and 2.5% citric acid solution, respectively, by differential and density-gradient centrifugation. Examination of the mitochondrial preparations by electron microscopy and the assay of several marker enzymes indicated that they consisted mostly of mitochondria with some microsomal contamination. The nuclear preparations were substantially free from contaminants as judged by particle counts with the aid of phase and electron microscopy. The lipid compositions of the mitochondria from both species were characterized by a high concentration of cardiolipin and low concentration of cholesterol and sphingomyelin and an absence of glycosphingolipids as compared with the lipid composition of the whole epidermal cell. The lipid compositions of the nuclei were characterized by a high proportion of phosphatidyl choline and an absence of glycosphingolipids. The neutral lipids accounted for an unusually high proportion of the total lipids especially in human epidermal nuclei. Although the technical difficulties in isolating subcellular organelles from mammalian epidermis limit the yield and quality of the mitochondria, these preparations as well as those of nuclei are superior to preparations reported previously and are pure enough for a valid comparison with other membrane systems of the epidermal cell.

Animals↗
PubMed1975

Lipid compositions of cells isolated from pig, human, and rat epidermis.

Epidermal slices from pig, human, and rat skin were treated with dilute buffered trypsin solution (0.005%, w/v), and suspensions of mixed basal and spinous cells were obtained in good yield. Total lipids accounted for approximately 8% of the pig, 10% of the human, and 20% of the rat epidermal cell (dry weight). Phospholipids in pig, human, and rat cells accounted for, respectively, 62%, 53%, and 35% of the total lipids. Phosphatidylcholine (34-38%), phosphatidylethanolamine (18-23%), and sphingomyelin (17-21%) were major compounds in all species. The major neutral lipids were sterols (mostly cholesterol) and triglycerides. Free fatty acids were a major lipid class in pig and human cells, whereas wax esters were a major component in rat epidermal cells. Nearly half (45%) of the sterols in rat cells but less than 10% of those in pig and human cells were esterified. Cholest-7-ene-3beta-ol accounted for 20% of the total sterols in rat cells. Cholesteryl sulfate and ceramide were minor lipids in the three species. The predominant glycosphingolipid (greater than 99%) was glucosylceramide, which accounted for 7% and 9%, respectively, of the total lipids in pig and human cells. A significant proportion (pig, 17%; human, 11%) of the fatty acids in the glucosylceramides were C26:0 and C28:0.

Animals↗
PubMed1975

Different populations of pig epidermal cells: isolation and lipid composition.

Preparations representing populations of (a) basal and spinous cells, (b) granular cells, and (c) stratum corneum cells were obtained by successive treatments of epidermal slices from pig skin with dilute buffered trypsin solutions. Total lipids accounted for about 8% of the cell dry weight in each of the three populations. Phospholipids, which predominated in the basal and spinous cells, accounted for only 21% of the total lipids in the granular cells and less than 0.1% in the stratum corneum. The latter cells contained more cholesterol (23% of total lipid) than either the granular cells (18%) or the basal and spinous cells (8%). The proportion of ceramide was also much higher in the stratum corneum (17%) and granular cells (9%) than in the basal and spinous cells (1%). The relative amounts of glycosphingolipid (glucosylceramide) and cholesteryl sulfate in the total lipids of stratum corneum cells were less than half those in the granular cells and basal and spinous cells. A novel phospholipid was a major component (26% of total) of the phospholipids from granular cells. The compound, which was partially characterized, contained phosphorus, fatty acids, and glycerol (molar ratio 1:3:2) and appeared to be a neutral derivative of phosphatidic acid.

Animals↗