Biomedical subjects

W D Davidson

Publications and source records attributed to W D Davidson.

At least 37 records · Page 2Linked to original sources

PubMed1978

Ornithine as a possible marker of cancer.

The nonprotein amino acid ornithine is the major source of polyamines in mammalian physiological systems. Increased urinary polyamine levels have been demonstrated in humans with varied types of cancers. The metabolism of DL-[1-14C]ornithine monohydrochloride in rats with either Walker 256 carcinoma or chemically induced methylcholanthrene tumors was studied. Following the i.p. injection of 3 muCi[14C]ornithine per 100 g body weight, the decarboxylation of ornithine-yielding 14CO2 was monitored by utilizing the vibrating reed electrometer-ionization chamber model of Davidson and Schwabe. Tumor-bearing animals showed significant increases in ornithine metabolism as compared to controls; for Walker 256 the tumor-bearing animal to control ratio rose from 1.16 to 1.78, for methylcholanthrene implants it rose from 1.19 to 1.82, and for methylcholanthrene paintings it rose from 1.00 to 2.20. With tumor regression ornithine levels of metabolism in the tumor-bearing animals returned to base line or nearly base-line levels. These results encourage us in our attempt to develop ornithine as a biological marker of cancer.

Animals↗

PubMed1977

Lipid metabolism in plasma, liver, and adipose tissue of rats with experimental chronic nephrotic syndrome.

Plasma, liver, and adipose tissue lipid composition and synthesis from [1-14C] acetate were studied three months following induction of nephrotic syndrome in rats by injection of antiglomerular basement membrane protein. Plasma triglyceride concentrations and specific radioactivities were elevated, and the triglycerides contained increased proportions of oleic acid. Plasma cholesterol and phospholipid concentrations were also increased, but free fatty acid levels were not. Liver triglyceride concentrations were decreased and incorporation of [1-14] acetate into liver triglycerides was also depressed below that of normal controls. Nephrotic rat liver triglycerides contained a higher proportion of oleic acid and lower arachidonic acid than did controls. Incorporation of [1-14C] acetate into adipose tissue lipids of the nephrotic rats was increased, and the proportion of palmitic acid was decreased. In the chronic nephrotic rat, the major source of the increased plasma triglycerudes may be fatty acids mobilized from adipose tissue stores.

Acetates↗

PubMed1977

Kinetics of infused acetate and effect on plasma pyruvate and lipid concentrations in uremic and non-uremic dogs.

During acetate infusion at a rate of 10 millimoles/kg/hr arterial blood acetate levels rose progressively to maximums of 7.9 +/- 1.7 mM in uremic dogs and 10.8 +/- 1.4 mM in non-uremic dogs. Following cessation of infusion, removal of acetate followed first order kinetics. Acute uremia had no significant effect on mean clearance rates of acetate (1.28 +/- 0.28 L/kg/hr uremics vs 0.92 +/- 0.22 in non-uremics) or upon blood half-life of acetate following infusion (9.7 min. vs 10.9 min.). Plasma pyruvate levels rose during infusion from 1.5 to 4.4 mg/dl in the uremic dogs and following infusion rose further to 6.5 mg/dl. In the non-uremic dogs pyruvate was not significantly elevated until 30 min. post-infusion. Plasma free fatty acids increased from 79 to 131 mumoles/dl during acetate infusion in the uremic dogs, but did not change significantly in the non-uremic group. Plasma cholesterol and triglycerides increased after induction of uremia, but showed no significant changes as a result of acetate infusion in either group. These results suggest that the electrolyte and lipid abnormalities that occur in hemodialyzed uremic patients may be related to the acetate load these patients receive during dialysis.

Acetates↗

PubMed1974