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Biomedical subjects

R J Arnold

Publications and source records attributed to R J Arnold.

24 records · Page 2Linked to original sources
PubMed1979

The effects of food deprivation and re-feeding on bovine adipose-tissue glycogen synthase.

Bovine adipose-tissue glycogen metabolism was studied during food deprivation and re-feeding. Changes in the specific activity of adipose-tissue glycogen synthase paralleled changes in tissue glycogen content: both parameters increased during food deprivation and remained so during the first 10 days of re-feeding. The values for the A0.5 (activation constant) for glucose 6-phosphate of the freshly isolated enzyme from adipose tissue from fed and starved steers were 2.9 +/- 0.1 mM and 0.90 +/- 0.05 mM respectively. Additionally, whereas incubation of adipose-tissue extracts from fed steers did not activate endogenous glycogen synthase (through a presumed phosphoprotein phosphatase mechanism), the enzyme from starved or re-fed (up to 3 days re-feeding) steers was reversibly activated as measured by changes in the value for the A0.5 for glucose 6-phosphate. Thus activation of bovine adipose-tissue glycogen synthase during food deprivation appears to be related to expression of glycogen synthase phosphatase activity. These effects of food deprivation on bovine glycogen metabolism contrast markedly with the effects observed in rat adipose tissue.

Adipose Tissue↗
PubMedDate not supplied

Amino acid patterns of infants of very low birth weight. I. Characterization and clinical significance of change over time.

Plasma amino acid levels were determined in 40 premature, very low birth weight infants. All blood samples were drawn prior to parenteral nutrition and blood transfusions. Levels were taken from 0 to 90 hours after birth at approximately 12-hour intervals. Dextrose 5% or 10% in water was given intravenously, beginning shortly after birth, as the only caloric source. A total of 69 plasma amino acid determinations were used for statistical analysis of 25 amino acids versus time. Plasma amino acid profiles were separated into several time intervals. An analysis of covariance of the means of these intervals demonstrated a statistical difference (p less than or equal to 0.01 or better) for taurine, lysine, alanine, threonine, valine, tryptophan, cystine and free cysteine/cystine. Thus, plasma amino acid levels should be reviewed in relation to the hours after birth of sampling. By 12 hours after birth, a relatively stable pattern was observed for all amino acids except taurine. Taurine levels continued to decline throughout the observation period. No statistically significant correlations were observed between the plasma amino acid levels and gestational age.

Amino Acids↗
PubMedDate not supplied

Cost-effectiveness of antihypertensive agents in patients with reduced left ventricular function.

A pharmacoeconomic primer reviews current economic models used to analyze and synthesize information that may be considered in certain health-related policies or clinical decisions. Heightened budgetary pressures concomitant with mandates for demonstrable increases in efficacy and safety have fostered greater use of cost-effectiveness analyses (CEAs) throughout the health care industry. In the field of hypertension, major clinical trials of pharmacotherapeutic regimens generally demonstrated benefit of reducing blood pressure; CEAs supplied additional data concerning the optimum selection among alternative antihypertensive therapies. As interest has focused on the preservation of left ventricular (LV) function for the best prognosis, it has become increasingly evident that not all antihypertensive regimens affect LV function in the same way. Thus CEA may be an appropriate method to evaluate these effects and facilitate the identification of a regimen that minimizes deterioration of LV function.

Antihypertensive Agents↗