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S R Powell

Publications and source records attributed to S R Powell.

41 records · Page 3Linked to original sources
PubMedDate not supplied

Salicylate trapping of .OH as a tool for studying post-ischemic oxidative injury in the isolated rat heart.

The use of salicylate as a chemical trap for .OH represents a simple and convenient alternative to the use of spin trapping techniques to study oxidative injury in isolated perfused organs. In these systems, salicylate is included in the perfusion buffer at concentrations ranging from 0.1 to 2 mM depending on the detection apparatus employed. In our studies, we have used a coulometric detector, which has a theoretical efficiency of 100% as compared to 1-5% for the standard glassy carbon electrode. We have been able to generate reproducible results by inclusion of only 100 microM salicylate, a concentration demonstrated not to affect pre- or post-ischemic cardiac function. In initial studies, we observed an increase in perfusate 2,5-dihydroxybenzoic acid consistent with an early post-ischemic burst of .OH, not unlike that reported using spin trapping techniques. Since then we and others have used this technique to examine possible relationships between .OH formation and treatments that alter post-ischemic cardiac functional recovery. For example, preischemic loading of hearts with copper results in increases in post-ischemic dysfunction and LDH release that were associated with an increase in 2,5-dihydroxybenzoate and by inference, .OH formation. Alternatively, we have reported that the nitroxide spin label, TEMPO, reputed to be a superoxide dismutase mimetic, decreased post-ischemic arrhythmias and 2,5-dihydroxybenzoate formation. Most recently, we have observed that preischemic loading of hearts with zinc-bis-histidinate results in improved post-ischemic cardiac function and decreased LDH release; changes that were associated with decreased 2,5-dihydroxybenzoate formation. These studies indicate that under certain conditions, salicylate is a valuable alternative to spin trapping techniques to probe the role of .OH in cardiac oxidative injury, particularly when applied to the isolated perfused heart preparation.

Animals↗
PubMedDate not supplied

Handling and acceptability of the Easi-Breathe device compared with a conventional metered dose inhaler by patients and practice nurses.

This study compared the handling and acceptability of the Easi-Breathe, a breath-actuated metered dose inhaler (MDI), with that of a conventional MDI. A total of 104 patients and 14 practice nurses took part in interviews at a central location. An additional 100 practice nurses were interviewed in a telephone study. Significantly more patients (86%) found Easi-Breathe easier than a conventional MDI to use correctly (p < or = 0.001). Overall, more patients preferred Easi-Breathe (82% vs 18%; p < or = 0.001), ease of use and confidence in successful dose delivery being the main reasons for their preference. Nurses thought that Easi-Breathe was easier for the vast majority of patients (97%) to use correctly, as well as being easier to teach and to use correctly in a crisis (p < or = 0.001). Overall, 79% of nurses preferred the Easi-Breathe to the conventional MDI (p < or = 0.001), ease of use and ease of teaching being the main reasons for their preference.

Adolescent↗