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Biomedical subjects

M E Gray

Publications and source records attributed to M E Gray.

50 records · Page 3Linked to original sources
PubMed1979

Effect of epidermal growth factor on lung maturation in fetal rabbits.

Injection of epidermal growth factor (EGF) into 24-day rabbit fetuses (5 microgram, im or ip) induced accelerated maturation of the lung. On sacrifice at day 27, there was greater distensibility and stability on deflation associated with the appearance of a complement of type II cells approaching that of the rabbit at term. EGF treatment had no demonstrable effect on body weight or lung weight in this group of animals. Saline-injected control fetuses were not affected significantly.

Animals↗
PubMed1979

The effects of ACTH on lung maturation in fetal lambs.

The ability of adrenocorticotrophic hormone (ACTH) to induce lung maturation was evaluated in fetal lambs. One member of 14 twin pairs between 114 and 138 days of gestation was infused intravenously with 0.5 mg ACTH over 5 days. The lungs of treated versus control lambs were judged more mature by morphologic criteria by the use of light and electron microscopy and by biochemical criteria by the use of lamellar-body-rich cell fractions. None of 5 premature lambs treated with ACTH and allowed to breathe showed evidence of hyaline membrane disease, while 3 untreated control lambs showed typical hyaline membranes.

Adrenocorticotropic Hormone↗
PubMed1978

The lipid composition of isolated rat spermatids and spermatocytes.

The lipids composition of enriched fractions of spermatids and spermatocytes, isolated from rat testicular tissue, has been investigated. More than 20% of the total fatty acids of spermatids but only 10% of those of spermatocytes, isolated from testes of mature rats, was 4,7,10,13,16-docosapentaenoic acid. Spermatocyte-enriched fractions isolated from testes of immature rats had fatty acid compositions similar to those isolated from testes of mature rats. On the other hand, spermatids isolated from immature rats had a level of docosapentaenoic acid which was intermediate between the level found in spermatocytes and that of spermatids from mature rats. Major phospholipid classes and the triacylglycerols of spermatids contained much more of the docosapentaenoic acid than the corresponding lipid types from spermatocytes. Differences in content of total phospholipids, individual classes of phospholipids and triacylglycerols among spermatocytes, spermatids and late spermatids were also observed.

Aging↗
PubMed1978

Intracellular granules of the renal medulla in a case of potassium depletion due to renal potassium wasting. Electron microscopic comparison with renal medullary granules in the potassium-depleted rat.

An electron microscopic comparison was made of intracellular granules of the renal papilla and inner medulla in two types of potassium depletion: one in a 47-year-old white male with chronic potassium-wasting renal disease and the other in the experimentally depleted rat. The granules in both cases were composed of small and large vesicles; myelin figures; small particles; and dense bodies, with a partial, or complete, single limiting membrane. Ultrastructurally, the constituent elements of the granules were essentially the same in the two types of potassium depletion. It was concluded that the intracellular granules in the human tissue were the result of potassium depletion and a counterpart to those in the potassium-depleted rat.

Animals↗
PubMed1972

Role of plasma lipoproteins in cortisone-induced fat embolism.

The clinical syndrome of fat embolism can be a complication in patients who have suffered long-bone fracture, and has been associated with a number of conditions in which bone fracture is not a factor. The origin of embolic fat (bone marrow or depot fat versus plasma lipoproteins) has been debated. To test the hypothesis that alterations in the composition of plasma very-low-density lipoproteins (VLDL) could lead to their coalescence and subsequent impaction in pulmonary vasculature, New Zealand white rabbits were injected intramuscularly with 25 mg of cortisone twice a day for 2, 4, 6, 11 and 12 days. Blood samples were obtained from unanesthetized animals prior to the cortisone treatment and at sacrifice. Pulmonary fat embolism that was similar histologically to that found in the human patient with the clinical syndrome was produced in all rabbits treated for 4-12 days. After the fourth day, all animals were hyperlipidemic. There was a tenfold increase in plasma VLDL concentration and the mean particle diameter of the VLDL was increased from 620 A to 1016 A. The proportion of triglyceride (TG) was increased, protein (PR) and phospholipid (PL) were decreased and total cholesterol (TC) was unaltered (untreated controls: PR, 16.4%; TG, 58.5%; PL, 19.2%; TC, 6.7% and cortisone-treated: PR, 8.4%; TG, 75.1%; PL, 11%; TC, 6.4%). The lipid composition of pulmonary embolic fat from rabbits treated with cortisone for 6 or 11 days was TG, 81%; PL, 13% and TC, 6%. VLDL from similarly treated rabbits had a lipid composition of TG, 79%; PL, 14.5% and TC, 6.6%. The TC concentration of bone marrow and depot fat from animals treated with cortisone for 11 days was <1%, and the PL concentration was <2%. These data support the hypothesis that plasma lipoproteins, primarily the VLDL, when altered in size and composition can coalesce into globules of sufficient size to occlude peripheral capillaries.

Adipose Tissue↗