Biomedical subjects

S Lemeshow

Publications and source records attributed to S Lemeshow.

93 records · Page 6Linked to original sources

PubMedDate not supplied

Pathophysiology of superoxide radical as potential mediator of reperfusion injury in pig heart.

The role of oxygen-derived free radicals in myocardial reperfusion injury was studied using the isolated in situ pig heart model. The free radical scavengers, superoxide dismutase (SOD) and catalase, protected the ischemic pig heart subjected to one hour of normothermic regional ischemia followed by one hour of global hypothermic arrest and one hour normothermic reperfusion. A significant increase in thiobarbituric acid reactive material and oxidized glutathione appeared in the perfusate demonstrating free radical-mediated lipid peroxidation during reperfusion, and this was prevented by the addition of SOD plus catalase. The values of three important antioxidative enzymes, SOD, catalase, and glutathione peroxidase, showed reduced activities after 2 hours of ischemia. These values did not change significantly after 60 minutes of reperfusion following the 2 hours ischemic insult. The concentrations of high-energy phosphate compounds including creatine phosphate (CP), adenosine triphosphate (ATP), and total adenine nucleotide were reduced significantly during ischemia and reperfusion in hearts which were not protected by SOD and catalase. The plasma creatine phosphokinase levels were lowered appreciably as a result of SOD and catalase treatment. It may be concluded from these experiments that oxygen-derived free radicals are present during reperfusion and SOD and catalase play a significant role in the protection of ischemic myocardium from reperfusion injury.

Adenine Nucleotides↗

PubMedDate not supplied

Heavy smoking among a sample of employed women.

Understanding the phenomenon of heavy smoking among women and factors related to it is of considerable public health importance. Whereas lighter smokers have been more successful in their cessation attempts, the percentage of smokers who smoke more than 25 cigarettes per day has increased in recent years. This article examines the hypothesis that, compared to lighter smokers, female heavy smokers will report more responsiveness to internal cues to smoke, less interest in quitting, more difficulty with previous cessation attempts, more uncertainty about cessation strategies, and more concern about weight gain as a result of quitting. We collected data in 1984 through a self-administered survey completed by 874 women employed as nurses in acute care, chronic care, and home care nursing in Worcester, Massachusetts; we base our analyses on data collected from 158 light and moderate smokers and 67 heavy smokers. Our findings suggest that, compared to lighter smokers, heavy smokers may depend more on nicotine and are likely to respond to a broader array of cues to smoke, factors that appear to contribute to heavy smokers' greater difficulties with quitting. These female heavy smokers are just as likely as lighter smokers to have made previous attempts to quit and want to quit just as much. Major barriers to quitting for female heavy smokers include a lack of confidence in their ability to quit, insufficient tools to succeed with cessation attempts, and fear that weight gain will accompany quitting.

Adult↗

PubMedDate not supplied

A clinical comparison of potassium and magnesium-potassium crystalloid cardioplegia: metabolic considerations.

Controlled metabolic studies were used to gauge the relative efficacy of two cardioplegic solutions in 28 patients (14 in each group) undergoing multiple coronary artery bypass grafts. A solution containing magnesium-potassium (Plegisol) was compared to a standard potassium crystalloid cardioplegic solution. Measurements of coronary blood flow, coronary vascular resistance, coronary arteriovenous oxygen difference, myocardial oxygen consumption and extraction, and myocardial lactate and potassium extraction and release were all measured in the isolated, vented, paced, beating heart, before and for 15 minutes after a one hour arrest interval during which time revascularization was completed. During cardioplegic administration, the infusion flow rate, myocardial oxygen consumption and extraction, and lactate and potassium release and uptake were noted. The results indicate that during cardioplegic administration, the total oxygen consumed for both potassium and magnesium-potassium solutions did not significantly differ. The flow rate of the Mg-K solution was significantly higher than that of the potassium solution alone (510 vs. 398 ml/min). There was no lactate production during Mg-K administration, but 0.13 mEq/min of lactate was produced while potassium crystalloid cardioplegia was given. During myocardial reperfusion, oxygen extraction was maintained near prearrest levels in both groups. The only significant difference noted between the potassium and magnesium-potassium solutions were the higher coronary blood flow and oxygen consumption immediately upon reperfusion in the Mg-K group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗