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Biomedical subjects

R Farrell

Publications and source records attributed to R Farrell.

29 records · Page 2Linked to original sources

The removal of infused leucine after injury, starvation and other conditions in man.

1. To investigate the effects of starvation, elective surgery, accidental injury and other clinical conditions on the metabolism of branched-chain amino acids in man, we have measured the basal concentration of leucine and the removal of metabolic effects of infused L-leucine. 2. The blood concentration of leucine as significantly increased by surgery, starvation and accidental injury, and decreased in cirrhosis. It tended to increase in diabetes and was unaffected by muscular dystrophy. 3. The half-life of infused leucine was nearly doubled by 4 days of complete starvation, unaltered by surgery and decreased by severe accidental injury, Infusion with Intralipid, which increased free fatty acid and ketone-body concentrations, had no effect on the removal of a leucine load. The clearance rate of infused leucine was reduced in diabetes and muscular dystrophy and increased in cirrhosis. 4. The effects of infused leucine on blood glucose and ketone bodies differed according to the groups studied. 5. Since the traumatized patients were given sufficient energy and nitrogen and disposed of a leucine load at a different rate from the starved patients, the causes of the increase in blood concentration of leucine in these two conditions are different.

Adolescent↗

Corneal swelling at low atmospheric oxygen pressures.

Corneas of 28 human subjects were exposed to oxygen partial pressures, in a gas goggle, of either 6.9, 17.1, or 22.2 mm Hg, and the corneal swelling was measured by pachometry for 4 hr. Following an initial rise, the swelling stabilized after about 3 hr; in many subjects it was reversed, indicating an adaptation process. The average corneal swelling after 4 hr for the three oxygen partial pressures was 5.07%, 2.13%, and 1.66%, respectively. The average minimum oxygen requirement to prevent corneal swelling was at least 23 mm Hg and varied significantly among individuals. The variations in swelling responses were large enough to explain clinical differences in edema of patients wearing oxygen-permeable contact lenses, in the absence of adequate tear pumping.

Adaptation, Physiological↗

Muscle-protein catabolism after injury in man, as measured by urinary excretion of 3-methylhistidine.

1. Urinary excretion of 3-methylhistidine, an index of the rate of muscle breakdown, has been measured during the first 7 days in patients after elective surgery or accidental injury. 2. There was no major difference between the mean daily excretion after skin grafting or total hip replacement, or in injured patients who were hyperketonaemic for the first 24 h after admission. 3. The group of injured patients who did not develop hyperketonaemia had a mean urinary 3-methylhistidine excretion which was twice that of the other groups. 4. It is concluded that increased breakdown of muscle protein makes a major contribution to the greater urinary nitrogen excretion in the normoketonaemic group of injured patients.

Adolescent↗

Branched-chain amino acids, nitrogen excretion and injury in man.

1. Venous blood concentrations of the branched-chain amino acids, valine, leucine and isoleucine, and urinary nitrogen excretion have been measured in sixteen adult males, from 2 h to 7 days after injury, and in four adults after elective skin grafts. 2. In the injured group the concentrations of these amino acids rose significantly 24 h after injury and had doubled at 4 days and remained high; in contrast the skin-graft patients showed no significant change. 3. In those injured patients with initial hyperketonaemia, defined as more than 0-2 mmo1/1, the increase in concentrations of branched-chain amino acids at the fourth and seventh days after injury was significantly less than in those with normoketonaemia, and was accompanied by lower urinary nitrogen excretion throughout the whole period. 4. It is suggested that the changes in the concentration of branched-chain amino acids after injury indicate decreased uptake by muscle or excessive release due to an imbalance between protein synthesis and protein catabolism in this tissue.

Adolescent↗

Colonoscopy associated bacteremia.

Fifty-two patients undergoing uneventful diagnostic colonoscopy with or without polypectomy and biopsy were evaluated for evidence of bacteremia during and after the procedure. In only two instances was bacteremia noted. Positive findings were noted in patients with carcinomatosis and severe liver involvement. These data suggest that routine prophylactic antibiotic coverage is unnecessary in uncompromised patients. Further studies are warranted when patients have either severe liver involvement or impairment of normal host defense mechanisms.

Adult↗

Experience with the use of the Carboflator for establishing pneumoperitoneum.

Safe and adequate pneumoperitoneum is dependent upon intraperitoneal pressure and not upon the number of liters of gas insufflated. Volume of gas delivered depends upon the size of the patient and whether there is any possible leakage. The Carboflator is a useful instrument for establishing controlled insufflation of gas and fail-safe intraperitoneal pressure.

Laparoscopes↗

The effects of dilute epinephrine saline irrigation on the need for tourniquet use in routine arthroscopic knee surgery.

A prospective, randomized, double-blinded study was performed to determine whether dilute epinephrine saline irrigation (1 mg/l) delivered by gravity flow would significantly reduce the need for tourniquet use during routine arthroscopic surgery. One hundred five patients requiring straightforward arthroscopic knee surgery were randomly assigned to either an epinephrine group that received dilute epinephrine irrigation by gravity flow or to a placebo group that received normal saline irrigation by gravity flow. The need for tourniquet use and the tourniquet time, total operative time, and volume of irrigation fluid used were documented and compared between the two groups. A tourniquet was required 50% less often in the epinephrine group than in the placebo group. This difference was found to be statistically significant using the Student's t-test (P < 0.008, alpha < or = 0.05). If a tourniquet was required, the presence of dilute epinephrine in the irrigation fluid did not affect the overall tourniquet time or the ratio of tourniquet time to total operative time. We believe this study proved that dilute epinephrine irrigation is effective in decreasing the need for tourniquet use during routine arthroscopic knee surgery.

Adult↗