Volume 100, Issue 1

This article describes the sensitivity and specificity of troponin I when compared to creatine kinase-MB (CK-MB) and electrocardiography (ECG) for diagnosing acute myocardial infarction (AMI). Two different lower levels for defining positive results with troponin I were evaluated. A retrospective study of 153 patients who presented to the emergency department of a community hospital supplied the pool of patients for this study. Patients included in this study were those for whom a CK-MB was ordered. The majority of these patients were evaluated for chest pain or symptoms suggesting an acute cardiac event. Of the 153 patients studied, CK-MB results were positive in 91 (59%) patients; ECG revealed AMI in 72 (47%) patients. There were 103 (67%) patients who had either positive CK-MB or ECG results. Ninety (59%) patients had a troponin I level greater than 2.0 ng/mL, and 18 (12%) patients had a troponin I level between 0.6 and 2.0 ng/mL. Seven patients whose troponin I level was between 0.6 and 2.0 ng/mL had negative CK-MB and ECG results. Therefore, 11 patients with troponin I between 0.6 and 2.0 ng/mL had AMI. Five patients with positive troponin I results (> 2.0 ng/mL) had negative CK-MB and ECG results. When a troponin I level greater than 0.6 ng/mL was used as a positive value, compared to CK-MB and ECG using either time zero or time 6 hours, the sensitivity was 94% and specificity was 81%. When troponin I greater than 2.0 ng/mL was used to define a positive test, the sensitivity was 85% and specificity was 91% when compared to CK-MB and ECG.

Leukotrienes are proinflammatory mediators with special significance in asthma. Released by numerous cell types, particularly after exposure to allergens, leukotrienes cause a potent contraction of bronchial smooth muscle, resulting in reduced airway caliber. Further, they cause plasma to leak from the vessels, resulting in edema, and enhance the secretion of mucus--both events that increase airway obstruction. Thus, leukotrienes have been a target of basic research in asthma. To date, a number of antileukotriene agents have been developed, and three are currently being used in clinical practice in the United States: zafirlukast and montelukast act by antagonizing the leukotriene receptor, and zileuton inhibits leukotriene synthesis. Studies have shown that these agents improve asthma symptoms, pulmonary function, and patient quality of life. Antileukotriene agents have generally been associated with a low incidence of side effects and good tolerability. Currently recommended for mild-to-moderate, persistent asthma, these agents have enabled patients to reduce their use of corticosteroids.