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Biomedical subjects

S Edwards

Publications and source records attributed to S Edwards.

At least 271 records · Page 15Linked to original sources
PubMed1979

The effect of inhibitors on the oxygen kinetics of terminal oxidases of Acanthamoeba castellanii.

1. Respiration of growing cultures of Acanthamoeba castellanii is inhibited less than 60% by azide (35 mM); the respiration of early-exponential-phase cultures differs from that of late-exponential-phase cultures in being stimulated by up to 120% by low concentrations (less than 1 mM) of this inhibitor. Azide (0.5 mM) plus 1 mM-salicylhydroxamic acid gives 80% inhibition of respiration in early- or late-exponential-phase cultures. 2. Lineweaver-Burk plots of 1/v against 1/[O2] for growing and stationary-phase cultures give values of less than 1 muM for the apparent Km for oxygen. 3. These values are not significantly altered when determined in the presence of 1 mM-salicylhydroxamic acid. 4. Higher values (greater than 7 muM) for apparent Km values for oxygen were obtained in the presence of azide, which gives non-linear Lineweaver-Burk plots. 5. Competitive inhibition of respiration by CO occurs with Ki 2.4 muM. 6. The results are discussed in terms of the presence of three terminal oxidases in this organism, namely two oxidases with high affinities for oxygen (cytochrome c oxidase of the main phosphorylating electron-transport chain and the salicylhydroxamic acid-sensitive oxidase) and a third oxidase with a low affinity for oxygen, sensitive to inhibition by cyanide but not by azide or salicylhydroxamic acid. The relative contributions to oxygen utilization by these oxidases change during the growth of a batch culture.

Amoeba↗
PubMed1976

Relation of urinary total hydroxyproline: Creatinine ratio to height velocity in children with retarded growth.

The urinary total hydroxyproline:creatinine ratio was measured on samples collected from 18 boys and 11 girls referred to a children's hospital because of small stature. Any serious degree of growth hormone deficiency was excluded and each child's growth and development was recorded over the following year. The hypothesis that the average hydroxyproline:creatinine ratio on random urine samples may be used to predict height velocity was examined. Such a prediction would have been incorrect on 35% of occasions, and it is concluded that this investigation cannot be used reliability to predict growth in height; it is probably only useful with sequential studies of an individual child over short periods while monitoring therapy.

Adolescent↗