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Biomedical subjects

C H Miller

Publications and source records attributed to C H Miller.

At least 217 records · Page 12Linked to original sources

Myocardial sparing effect of fentanyl during halothane anaesthesia in dogs.

The cardiovascular effects of fentanyl (Sublimaze) were studied in seven mongrel dogs. A constant infusion of the drug was used to produce an apnoeic end-point while concomitant cardiovascular changes were monitored. After one hour the infusion was repeated while ventilation was controlled and atropine was given to eliminate the haemodynamic effect of changes in PaCO2 and heart rate. When PaCO2 was allowed to increase fentanyl reduced heart rate and mean arterial pressure markedly while left ventricular dp/dt was depressed moderately at the time of respiratory arrest. When heart rate and PaCO2 were kept constant there was little variation in the cardiovascular measurements during fentanyl infusion. We conclude that fentanyl allows relative myocardial sparing in dogs when used at clinically effective concentrations.

Anesthesia, Inhalation↗

Degradation of sucrose by whole cells and plaque of Actinomyces naeslundii.

Whole cells of Actinomyces naeslundii ATCC 12104, either in a dispersed form or in the form of plaque, enzymatically degraded sucrose to glucose and fructose. Washed whole cells expressed beta-fructofuranosidase specificity and hydrolyzed sucrose to essentially equimolar quantities of glucose and fructose. The cells readily hydrolyzed sucrose, raffinose, and Actinomyces viscosus or Aerobacter levanicum levan, but did not degrade melezitose, maltose, alpha-methyl-d-glucoside, melibiose, glucose-1-phosphate, or dextran T-500. Sucrose degradation occurred at a temperature optimum of 37 to 45 C and at a pH optimum of 5.7 to 6.0. The K(m) for sucrose was 0.05 M. Sucrose or raffinose in the growth medium resulted in cells with a specific activity that was fivefold greater than that of cells grown in medium supplemented with either glucose, fructose, maltose, lactose, or glucose and fructose, or grown in unsupplemented medium. Addition of sucrose to log-phase cells growing in glucose also increased the specific activity. Degradation of sucrose by whole cells in the form of plaque also occurred, but 6% less free fructose than free glucose was recovered. Sucrose-dependent synthesis of extracellular levan or glucan by whole cells or plaque could not be demonstrated. The ability of A. naeslundii to degrade sucrose and levan may be related to the pathogenic potential of this bacterium in plaque-associated oral diseases.

Actinomyces↗