Greater diagnostic sensitivity of treadmill versus cycle exercise testing of asymptomatic men with coronary artery disease.

Maximal hemodynamic and ventilatory responses using cycle and treadmill ergometer were compared in 52 asymptomatic patients with angiographically proved coronary artery disease. Moreover, test sensitivity with respect to ST-segment depression and typical angina pectoris were compared between exercise modes used. Exercise tests were performed on different days in randomized order. In 42 patients, exercise-induced myocardial ischemia, expressed as a fraction of left ventricular circumference, was assessed by thallium-201 scintigraphy. The main finding of this study was a significantly higher maximal oxygen uptake (1.87 +/- 0.4 vs 2.2 +/- 0.5 liters/min; p less than 0.001), heart rate (148 +/- 19 vs 158 +/- 18 beats/min; p less than 0.001) and rate-pressure product (28.3 +/- 5 x 10(3) vs 30.7 +/- 5 x 10(3); p less than 0.001) during treadmill walking than during cycling. Therefore, stress-induced myocardial ischemia was significantly more extensive after treadmill walking (31 +/- 37 degrees vs 45 +/- 40 degrees; p less than 0.001). Moreover, there were significantly more patients with signs of myocardial ischemia (ST-segment depression or typical angina pectoris, or both) during treadmill than during cycle ergometry (35 vs 25 patients; p less than 0.05). However, lactate levels measured at peak exercise (4.07 +/- 2.0 vs 4.38 +/- 1.9 mmol/liter) and 3 minutes into the recovery period (5.60 +/- 2.2 vs 5.80 +/- 2.2 mmol/liter) were comparable between both methods, indicating no significant difference in anaerobic energy production. These findings suggest that walking on a treadmill represents an exercise method with a greater ability than cycling to detect coronary artery disease.

Effect of corticosteroids on lung volume-pressure curves in bleomycin-induced lung injury in the rat.

In this study we investigated changes in volume-pressure curves at various stages after bleomycin induced lung injury (6 h, and 3, 7, and 28 days) and tested the ability of steroids to influence these changes. The most significant decreases in volume-pressure curves were observed at 3 days post bleomycin, a time point that correlates to the peak period of inflammation. Steroids as drugs of high antiinflammatory potency were used in order to modulate the inflammatory response and possibly the volume-pressure curve changes observed during the natural course of bleomycin induced lung injury. Dexamethasone treatment significantly inhibited the decreases in volume pressure curves observed at 3 days post bleomycin, whereas methylprednisolone did not. Also both steroids significantly inhibited inflammation as measured by histological evaluation and the presence of cells in the bronchoalveolar lavage fluid.

Correlation of changes in pulmonary surfactant phospholipids with compliance in bleomycin-induced pulmonary fibrosis in the rat.

Qualitative and quantitative analysis was performed on phospholipids isolated from bronchoalveolar lavage fluid during the development of pulmonary fibrosis in the rat. A single transtracheal injection of 2.0 units of bleomycin was administered to rats to induce lung injury. Animals were killed at 0, 3, 7, 14, 30, and 120 days after bleomycin treatment. Total lipid phosphorus in BAL from animals given bleomycin increased from 1.6 mumol/lung in normal animals to 3.2 mumol/lung at 14 and 30 days. The increase in phospholipids was primarily in phosphatidylcholine with minor increases in phosphatidylinositol and phosphatidylethanolamine. These quantitative changes were accompanied by qualitative changes that included an increase in the percentage of total phosphatidylcholine, disaturated phosphatidylcholine, and phosphatidylinositol. In contrast, the percentage of phosphatidylglycerol was significantly reduced. Plasma phospholipid analysis indicated that these alterations were not due to plasma contamination. The functional significance of the phospholipid changes was assessed by comparing air- and saline-filled compliance measurements at similar times after bleomycin. Abnormal compliance measurements were observed at 3, 7, and 14 days after bleomycin. At 3 and 7 days the predominant compliance defect was at the air-liquid interface; however, at 14 days, when phospholipids were significantly elevated, the defect was primarily due to tissue components.(ABSTRACT TRUNCATED AT 250 WORDS)