John E. Powe

Pulmonary accumulation of polymorphonuclear leukocytes in the adult respiratory distress syndrome

The polymorphonuclear leukocyte (PMN) plays an integral role in the development of permeability pulmonary edema associated with the adult respiratory distress syndrome (ARDS). This report describes 3 patients with ARDS secondary to systemic sepsis who demonstrated an abnormal diffuse accumulation of Indium (111In)-labeled PMNs in their lungs, without concomitant clinical or laboratory evidence of a primary chest infection. In one patient, the accumulation of the pulmonary activity during an initial pass suggested that this observation was related to diffuse leukoaggregation within the pulmonary microvasculature. A 4th patient with ARDS was on high-dose corticosteroids at the time of a similar study, and showed no pulmonary accumulation of PMNs, suggesting a possible reason for the reported beneficial effect of corticosteroids in human ARDS.

Three-phase bone scintigraphy. Asymmetric patterns in the upper extremities of asymptomatic normals and reflex sympathetic dystrophy patients.

Three-phase Tc-99m MDP scans of 61 patients with asymptomatic upper extremities randomly mixed with 17 studies of patients previously diagnosed with reflex sympathetic dystrophy were blindly interpreted by three observers. Asymmetry in any of the phases was recorded and a final diagnostic impression made. Thirteen of 17 reflux sympathetic dystrophy studies were rated abnormal by at least two observers. Mild to striking asymmetry was occasionally seen in all three phases in asymptomatic upper extremities. Twenty of 61 asymptomatic patients (33%) were rated abnormal by at least one observer, and 5 of 61 studies (8%) were rated abnormal by all observers. Asymmetries in normal patients occurred more commonly in the earlier phases, while asymmetry in the delayed images was mild in all but one. Tightening the criteria to exclude mild asymmetry in delayed images resulted in unacceptably low sensitivity for reflex sympathetic dystrophy (29%). Interob-server variability was most prominent in the flow and immediate images. In the diagnosis of reflex sympathetic dystrophy a greater reliance should be placed on the delayed images, which in themselves have an overall sensitivity of 94%. It is important, however, to recognize that occasional mild and rare moderate asymmetries in even the delayed images of normal individuals result in an overall lower specificity of 77%.

Functional results of gastric interposition following total esophagectomy.

Functional results of gastric interposition were evaluated in 35 patients at 3 to 84 months following esophagectomy. All patients were satisfied with the results of surgery, although 14 (40%) still experienced some degree of dysphagia. Transit times for radiolabeled solids across the cervical esophagus and anastomosis were not significantly different for the 14 symptomatic patients (mean 77 seconds) versus 21 asymptomatic patients (mean 55 seconds). Spontaneous emptying of the vagotomized intrathoracic stomach appeared complex, with mean percentage radionuclide clearances at 30 minutes (semisolid meal) calculated at 37% for 23 patients with early satiety (versus 42% asymptomatic) and at 38% for nine patients with reflux (versus 39% asymptomatic), all values comparable to emptying of the normal intra-abdominal stomach (35% clearance at 30 minutes). Our data suggest that the interposed stomach appears to retain its gastric identity rather than act as an inert conduit, and that although little correlation exists between postoperative symptoms and objective findings, the stomach remains a satisfactory esophageal substitute.

Pulmonary thallium-201 uptake following dipyridamole-exercise combination compared with single modality stress testing

Angiographic and clinical determinants of pulmonary uptake of thallium-201 were assessed in a laboratory setting where supine bicycle exercise is used for stress testing in the absence of limiting pharmacologic or physical factors, and where symptom-limited exercise is added to intravenous dipyridamole infusion in other cases. Angiographic correlation was available in 400 patients, including 130 tested with exercise, 94 in whom only handgrip or abbreviated bicycle exercise could be used after dipyridamole, and 176 in whom intravenous dipyridamole was combined with a significant level of exercise. For each test mode, lung/myocardial ratios on the immediate image were highly correlated (p less than or equal to 0.001) with a score based on the number of critical coronary artery stenoses, with grading by contrast ventriculography, and with the number of stenosed (greater than or equal to 50%) arteries; relationships (p less than 0.05) to history of myocardial infarction and to gender were also present. Multiple regression analysis showed the critical stenosis score and ventricular dysfunction to be the only significant determinants. When dipyridamole based tests were compared with exercise, curves of receiver-operating characteristics showed a tendency to better diagnostic performance. When dipyridamole is incorporated in stress testing, the value of increased lung uptake as an ancillary diagnostic sign is similar to that established for exercise.

Dipyridamole combined with symptom-limited exercise for myocardial perfusion scintigraphy: image characteristics and clinical role

Although dipyridamole can be used with myocardial scintigraphy to demonstrate reversible perfusion defects, combining exercise with the pharmacologic tool could improve image quality and information yield. The incidence of perfusion defects and the quality of thallium 201 images were reviewed in a series of 820 patients who had been assigned to a specific stress-test mode. Supine bicycle exercise alone was used (group 1) where no pharmacologic or physical factors (e.g., beta-blockers, arthritis) limited performance; otherwise, intravenous dipyridamole was followed by symptom-limited exercise (group II). Angiographic correlation was available in 57 patients in group I, and in 158 in group II; of these, 109 performed significant exercise (≥ 3 min at increasing workloads) following dipyridamole (group II A), whereas in 49 (group IIB) the exercise phase following dipyridamole was truncated. All test-mode groups were similar with respect to the incidence of ST segment depression during testing, patient throughput, and the sensitivity of perfusion defects. Chest pain and reversible defects were induced more frequently in group II than in group I. In group II A, splanchnic background activity was lower (P < 0.001) than in group II B, and the false-positive rate tended to be lower. Thus, combining exercise with dipyridamole in patients with non-cardiac limitations to exercise enabled the achievement of optimal results for perfusion scintigraphy.

Polymorphonuclear Leukocytes (PMNL)-Endothelium Interaction in Vitro: Effects of Isolation Techniques of PMNL

The hypothesis that polymorphonuclear leukocytes (PMNL) play a major role in the pathogenesis of vascular endothelial injury necessitates the need for techniques to isolate PMNL for subsequent experimental investigations. It has been suggested that various isolation protocols may alter the functional integrity of the isolated white blood cells. Extrapolation of this concept to the investigation of their role and mechanisms of interaction with vascular endothelium led this laboratory to investigate what effect in vitro isolation techniques had on aggregation response, oxygen radical chemiluminescence and the pattern of intracellular calcium response of stimulated PMNL.