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Biomedical subjects

P Burton

Publications and source records attributed to P Burton.

17 recordsLinked to original sources

A combination of electrocardiographic methods represents a further step toward the noninvasive identification of patients with syndrome X.

Identification of patients with angina but normal coronary arteriograms (syndrome X) using noninvasive means would be desirable. The ability of four established exercise electrocardiographic methods to identify angina patients with and without coronary artery disease was compared with that of a method based on a combination of the above (combined method). A treadmill score, a multivariate method, the ST segment recovery loop, the ST/heart rate adjustment, and the combined method were applied to 112 patients who had typical exertional angina and positive exercise tests (greater than 1 mm ST segment depression); 90 had documented coronary artery disease and 22 had syndrome X. The combined method and the treadmill score had a significantly higher diagnostic accuracy (both 81%, as 91 of the 112 patients were correctly identified by both methods) than the multivariate (66%) and ST segment recovery loop (64%) methods (p less than 0.05). The ST/heart rate adjustment had a lower sensitivity for syndrome X than any other method (1 of 22). Thus methods that involve the assessment of both ST and non ST segment variables have greater accuracy in separating syndrome X and coronary artery disease patients than methods relying more heavily on ST segment changes.

Adrenergic beta-Antagonists

Monitoring of occupational exposure to nitrous oxide.

The occupational exposure of operating room personnel to nitrous oxide was investigated by using multiple spot sampling, integrated personal sampling and end-tidal sampling in an operating room which had no ventilation system. The effect of passive scavenging on occupational exposure was determined. The study showed that all three methods to determine occupational exposure can yield representative time-weighted exposure patterns. However, the integrated personal sampling was considered the preferable method as it involved considerable saving of time and labour compared with taking and analyzing multiple end-tidal and spot samples. Passive scavenging of waste anaesthetic gases led to a three-fold to six-fold reduction of exposure of operating room personnel to nitrous oxide.

Air Pollutants

Thymic hormone-like restoration by human prealbumin of azathioprine sensitivity of spleen cells from thymectomized mice.

Gel filtration of fresh human serum revealed that over 95% of the thymic-hormone-like activity was present in the fraction representing the total albumin and prealbumin. Further studies demonstrated that the activity resided in the prealbumin fraction; albumin was inactive. Prealbumin was isolated from Cohn fraction IV-1 of pooled human plasma by extraction with aqueous buffer, fractionation with (NH4)2SO4, gel filtration on Sephadex G-150, and preparative disc gel electrophoresis. The final product was homogeneous by analytical gel electrophoresis was 40,000 times more active than the starting material in an azathioprine-sensitive rosette assay. Physical and chemical characterization studies showed that the isolated product was identical to authentic human plasma prealbumin. Isolation of the prealbumin fraction from sera of adult thymectomized mice revealed that the rosette activity was substantially lower than that isolated from sera of normal mice, suggesting a thymic dependence of the prealbumin activity. In vitro and in vivo bioassays of the fraction obtained prior to the final step of the purification procedure support the conclusion that prealbumin exhibits thymic hormone-like activity.

Animals

Magnesium and potassium content of normal heart muscle in areas of hard and soft water.

Concentrations of both magnesium and potassium were significantly increased in normal heart muscle samples from an area with a soft water supply compared with matched samples from an area with hard water. The zinc contrentration was also slightly increased in the soft water area. The magnesium/potassium ratio was significantly lower in the softwater area. This relative deficiency of magnesium may increase the risk of death after myocardial infarction in soft-water areas.

Adolescent

Effects of althesin anaesthesia and surgery on carbohydrate and fat metabolism in man.

The effects of Althesin anaesthesia alone, and associated with surgery, on carbohydrate and fet metabolism were studied in 36 patients by determining the plasma concentrations of cortisol, human growth hormone, insulin, free fatty acids, and blood sugar. The differences between the mean blood sugar and plasma cortisol concentrations before induction and during anaesthesia alone were not statistically significant. Blood sugar concentrations increased slightly during minor surgery and increased significantly during body surface and abdominal surgery. The plasma cortisol concentrations increased slightly during minor and body surface surgery but increased significantly during abdominal surgery. Plasma insulin and human growth hormone concentrations did not change appreciably during anesthesia and surgery. During Althesin anaesthesia alone and during minor surgery, a significant increase in plasma FFA concentration was observed at 15 min. The hyperglycaemia response in diabetic patients did not differ significantly from that in nondiabetic subjects. The clinical significance of the results is discussed.

Adolescent

Adrenocortical function related to Althesin anaesthesia and surgery in man.

Althesin anaesthesia alone had no significant effect on plasma cortisol concentration. When Althesin induction was followed by maintenance with N2O and halothane there was a statistically insignificant fall, but with N2O, pancuronium and I.P.P.V there was a tendency for plasma cortisol concentrations to rise. This, too, was statistically not significant. A significant elevation in the mean plasma cortisol concentration was only found in patients during abdominal surgery.

Abdomen